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2 PORGERA JOINT VENTURE ENVIRONMENTAL MONITORING JANUARY DECEMBER ANNUAL REPORT Prepared by: Environment Department PJV Communities & Environment Date: June 2010 Report No: PJV/ENV 1/10 Cover Photo: A magnificent male Ribbon-tailed Astrapia Bird of Paradise photographed by a Conservation International CI scientist within the proposed Mt Kaijende Wildlife Management Area WMA adjacent to the Porgera Gold Mine. Distinctive features include a greenish sheen on its head and breast, a pompom on the upper beak and a very long white ribbon tail. PJV provides funding and logistical support to CI for this important WMA project.

3 Land and Water New Illawarra Road, Lucas Heights NSW 2234 Locked Bag 2007 Kirrawee, NSW 2232, Australia Telephone: Facsimile: ABN Tim Omundsen Manager, Communities and Environment Porgera Joint Venture Enga Province Papua New Guinea 16 February 2011 Dear Tim, Re: Porgera 2009 Annual Environmental Report A CSIRO-led review team has reviewed a draft of the 2009 Porgera Annual Environmental Report and provided detailed comments for consideration. Overall, the report was found to be technically sound, however, as expected with a report of this size, a number of recommendations were made for improvement. Porgera Joint Venture PJV responded positively to most of the review team s recommendations and the final report has been modified in the light of these. Owing to time constraints, PJV elected not to address the following recommendations: i Inclusion of more details of field sampling and analytical methods; ii Use of advanced statistical methods to analyse data for trends; iii Inclusion of quality assurance/quality control data for all routinely measured chemical Parameters, and iv Suggested improvements to the way data are presented and summarised in the report. None of the above isssues constitute fatal flaws. We understand that these issues will be fully addressed in the 2010 Porgera Annual Environmental Report. Regards Dr Simon Apte Program Leader Contaminant Chemistry and Ecotoxicology Dr Graeme Batley Chief Research Scientist

4 2009 PJV Annual Environmental Report Executive Summary EXECUTIVE SUMMARY The 2009 Annual Environmental Report has been prepared by the Porgera Joint Venture PJV for the PNG Department of Environment and Conservation in accordance with PJV s Environmental Management Plan. The main highlights for 2009 are as follows: Hydrology and Sediment Transport Hydro-meteorological and sediment transport data collection continued during the year at stations within the mine site and on the downstream river system. Overall data recovery was 94%, which is a good improvement from the previous couple of years where recoveries were as low as 75%. Rainfall at the Anawe plant site and Open Pit mine were 11% and 24% above the longterm averages respectively, which was consistent with the pattern at other stations in the upper river system. River flows at all stations were also above long-term averages, as they have been for the last couple of years. Relatively little data pertaining to physical sedimentology were collected during the year due to law and order problems in areas where Environment staff were unable to operate, although monthly spot total suspended sediment TSS data were collected by the Chemistry section. However, four new profile cross sections were established in the Kaiya River for the purposes of monitoring aggradation due to sediment run-out from Anjolek Dump and valley wall erosion. In addition, existing profiles at SG2 and PF10 were re-surveyed adding valuable data to existing, long-term datasets. A review of sediment processes indicated that mine-derived inputs waste rock and tailings were generally low in 2009 compared to historic values. However, measured TSS values in mg/l at key stations along the river system, and the estimated suspended sediment load in Mt/y at SG3 were slightly elevated compared with predicted values and presumably resulted from the combined effect of high flows and a higher-than-normal rate of natural sediment input. Inspections of the erodible dumps and Kaiya, Pongema and Porgera Rivers showed no noteworthy change from the last reporting period. Both dumps appeared relatively stable and there was evidence that the rate of aggradation of the Kaiya River had slowed based on observations at Yuyan Bridge and the Kogai/Kaiya Junction. This was interpreted to mean that the pulse of sediment generated when the toe of Anlolek widened in 2007, had passed through the Kaiya River and had been flushed along the Porgera River. Cross sections undertaken at SG2 and PF10 both showed bed lowering. Four new cross sections were established in the Kaiya River for the purpose of monitoring channel change. Although the export of sediment from the erodible dumps could only be crudely estimated in the absence of monitoring data, it is noted that LiDAR surveys were conducted during the reporting period and it should be possible to undertake dump volume balance calculations in coming years to determine the loss of sediment downstream. PJV/ENV 1/10 ES-1

5 2009 PJV Annual Environmental Report Executive Summary Reviews of the 2009 hydrological and sediment transport data and monitoring were carried out by Chris Fink of CF Hydrometrics and Dr Andy Markham of Hydrobiology, respectively. Tailings Monitoring The average quantity of tailings discharged from the Process Plant during 2009 was 14,879 tonnes per day compared to the 2008 and 2007 average rates of 16,526 and 13,686 tonnes per day, respectively. As in previous years, monitoring of the tailings discharge was conducted on a daily basis during 2009 to independently check the automatic control systems and determine if the tailings neutralisation circuit was performing as designed. Tailings monitoring results for 2009 indicated that the neutralisation circuit operated efficiently during the year in detoxifying residual cyanide in the Process Plant tailings discharge. Dissolved concentrations of the various trace metals varied throughout The values for arsenic, copper and iron decreased while mercury increased. The noticeable decrease in copper is mostly likely due to a positive outcome of commissioning the Cyanide Destruction Plant CDP earlier in the year. All other dissolved metal values including cadmium, chromium, lead, nickel, silver and zinc showed no distinct trends. Over the 5-year period from , the dissolved concentrations of most metals decreased including arsenic, chromium, copper, iron, lead and nickel. Cadmium, mercury, silver and zinc showed no distinct trends over the same period. Total metal concentrations throughout 2009 showed no distinct trends with the exception of cadmium which decreased. Over the 5-year period from , there was no distinct trend for any metal. The concentrations of the various forms of cyanide in tailings, i.e. total, weak acid dissociable WAD, cyanide amenable to chlorination CAC and thiocyanate remained within acceptable limits during The most notable variations occurred in 2009 for total, WAD and CAC cyanide, and thiocyanate when the concentrations decreased noticeably due to the Cyanide Destruction Plant being commissioned in early Tailings ph mean values remained most of the time within the control limits ph during Compliance Monitoring at SG3 As in previous years, compliance monitoring was conducted during 2009 on the Upper Strickland River at Tumbudu, where the stream gauging station SG3 is located, to determine whether water quality compliance criteria set by the PNG Government were being met. Each month, a total of 16 samples was taken, i.e. one sample every 6 hours over a 4-day period and analysed for trace metals and other water quality parameters. All compliance criteria during 2009, as determined by the mean concentrations of the water samples analysed each month for various trace metals and other water quality parameters, were met in accordance with PNG Government requirements. PJV/ENV 1/10 ES-2

6 2009 PJV Annual Environmental Report Executive Summary Concentrations for all dissolved metals at SG3 remained relatively steady throughout 2009 with all values well below their respective compliance criteria. Sulphate concentrations showed no distinct trend during 2009 while the 5-year period from 2005 to 2009 showed a slight increase. Concentrations for dissolved ammonia remained steady at the detection limits for 2009 and from 2005 to The detection limit for ammonia dropped from 25µg/L to 5µg/L during 2009 due to analyses now being conducted at the NMI Lab in Sydney rather than the PJV Environmental Chemistry Lab. Statistical summary tables for trace metal concentrations at SG3 from 2000 to 2009 showed that the dissolved and total concentrations of mercury and silver decreased over the 10-year period while dissolved arsenic and zinc not total arsenic and zinc showed a similar decline. The dissolved and total concentrations of all other metals remained reasonably steady over the 10-year period. Summary tables for SG3 showing the results for 2009 and from 2000 to 2009 are shown on the following page. For 2009, the blank results for January indicate that no sampling was conducted due to Landowner concerns. PJV/ENV 1/10 ES-3

7 2009 PJV Annual Environmental Report Executive Summary Summary Table - Mean monthly trace metal concentrations at SG3 for 2009 all units in µg/l Month As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T Pb-D Pb-T Hg-D Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T Jan Feb < <1 122 < < < <1 180 < Mar < <1 81 < < < <1 105 < Apr < < < < <1 70 < May < < < < <1 104 < Jun < < < < <1 76 < Jul < < < < <1 120 < Aug < < < < <1 99 < Sep < < < < <1 51 < Oct < < < < <1 57 < Nov < < < < <1 78 < Dec < < < < <1 148 < Criterion NC 3 NC Note: D = dissolved; T = total; NC = no criterion Summary Table - Mean annual trace metals concentrations at SG3 since 2000 all units in µg/l except ph Year As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T Pb-D Pb-T Hg-D Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T ph-l < < < < <1 49 < < < < <1 67 < < < < < <1 58 < < < < <0.1 <0.1 <1 46 < < < < <0.1 < < < < < <0.1 < < < < < <0.1 <0.1 <1 59 < < < < <0.1 <0.1 <1 66 < < < < < <1 99 < Criterion NC 3 NC Note: D = dissolved; T = total; NC = no criterion; L = laboratory PJV/ENV 1/10 ES-4

8 2009 PJV Annual Environmental Report Executive Summary River Monitoring Water quality and bed sediment monitoring of the fate of trace metals from the Porgera operations was conducted during 2009 at a number of downstream locations from the mine site to Lake Murray. Off-river control sites on the Upper Lagaip River, Pori, Ok Om, Kuru, Baia and Tomu were included in the monitoring program. For each monitoring location, water quality samples were analysed for dissolved and total trace metals, and physical parameters, to assess water quality conditions in the Porgera/Lagaip/Strickland river system downstream of the mine. Bed sediment samples taken at the same locations along the river system were analysed for metals in the minus 63 micron <63µm size fraction and for total metals. This determined whether the trace metals were present in either the finer or coarser fraction. The mean dissolved concentrations of arsenic, chromium, copper, lead, nickel, silver and zinc for 2009 were below their SG3 compliance criteria at all downstream monitoring stations. Cadmium was below its SG3 criterion at all sites downstream of SG1. Total values of all trace metals decreased substantially from the SG1 monitoring station to the Lower Strickland River at SG5 due to dilution from natural suspended sediments from tributaries joining the main river. During 2009, the annual mean dissolved concentrations of all relevant trace metals at SG2 i.e. arsenic, cadmium, chromium, copper, lead, nickel, silver and zinc were lower than their respective compliance criteria set for SG3. This occurs even though SG2 is about one quarter the down-river distance to SG3 42km verses 165km. The 2009 mean annual value for copper at SG2 was 1.6µg/L, which is much lower than values obtained in previous years, and well below the SG3 compliance criterion of 10µg/L. This change is probably due to the commissioning of the Cyanide Destruction Plant within the process plant in December 2008 which has led to a decrease in the concentration of soluble metal cyanide complexes in mine tailings. Concentrations of all dissolve metals at SG3 now comply not only with the compliance criteria but with the stringent Australian and New Zealand water quality guidelines for ecosystem protection, indicating an absence of potential toxic effects, acute or chronic, on aquatic biota. In general, dissolved and total metals in the water column for arsenic, cadmium, chromium, copper, lead, mercury, nickel, silver and zinc have shown little change and display consistent trends downstream of the mine over the 10-year period from 2000 to For downstream bed sediments, particulate trace metal concentrations in the finer <63µm and total fractions showed considerable variability from the Porgera mine to SG5 in the Lower Strickland region. The values generally show a decrease as mine-derived sediments become diluted with the influx of natural sediments from tributaries along the river system. Sometimes this trend is difficult to see because of the relatively low number of samples taken during the year and the existence of background concentrations of metals in the natural sediments. For 2009, the dissolved and total concentrations for most metals decreased with increasing distance downstream of the mine. However, chromium showed no distinct trend for both the finer and coarser fractions, while nickel showed no distinct trend in the finer fraction only. PJV/ENV 1/10 ES-5

9 2009 PJV Annual Environmental Report Executive Summary Concentrations of dissolved metals in local creeks for 2009, in general, are similar to those obtained over the 5-year period from The higher results for some metals at 28 Level, Yakatabari Creek and Yunarilama Portal are due to discharges from the open pit and underground workings. The concentrations of dissolved zinc and cadmium, in particular, from the stable dumps for 2009 when compared with the 5-year period from show that metal leaching from minor sulphide oxidation within the dumps has remained reasonably steady and is currently not a concern. Metal leaching from the Kogai Stable Dump monitored at Kogai Toe has decreased over the past 10 years, probably due to a topsoil capping being put in place and thereby minimizing sulphide oxidation. In contrast, the Anawe North Stable Dump monitored at Wendako Creek, which has yet to be capped, continues to show signs of sulphide oxidation and subsequent metal leaching cadmium and zinc. This is expected to decrease, similar to the Kogai SD, once the Anawe North SD is capped. Total metal concentrations recorded for all local sites during 2009 were, in general, similar to those recorded for past five years from The results clearly show the predominance of total metals coming from the open pit and underground areas via 28 Level, Yakatabari Creek and Yunarilama Portal. All total metal values from these areas were relatively low and within acceptable limits. Dissolved metal concentrations in local creeks decrease rapidly downstream due to river dilution and adsorption onto natural sediments; however, total metals i.e. mainly metalbearing total suspended solids decrease by natural sediment dilution from landslides and tributaries of the Strickland River system. Local creek ph values for 2009 were generally consistent with historical monitoring data. The exception was the stream flowing from the lime plant, which was moderately alkaline ph Alkalinity measurements from the lime plant showed a range of results depending on plant operating conditions. Sulphate results showed elevated readings for water released from the starter dump A SDA toe, Yakatabari Creek and Yunarilama Portal as a result of minor sulphide oxidation in the open pit and underground areas. Wendako Creek downstream of the Anawe North dump also showed more significant elevated results from minor sulphide oxidation within the dump. Lake Murray Some mine-derived, metal-bearing sediment from the Strickland River enters the southern end of Lake Murray via the Herbert River, and deposition can occur within the lake. This results from flow reversals in the Herbert River approximately 15% of the time NSR, 1995, which are caused by high levels in the Strickland River from heavy rainfall in the mountains. In 2000, a significant natural breach of the western bank of the Strickland River occurred adjacent to the Mamboi River, which flows into Lake Murray. Sediment from the Strickland River, including some mine-derived sediment, has entered the southern end of Lake Murray via the Mamboi River since that time. As a consequence of Strickland River sediment entering Lake Murray, PJV is required to monitor the lake for the duration of the Porgera mine life. PJV s monitoring activities are concerned to a large extent with the origin, movement and fate of arsenic and mercury, while other trace metals and water quality parameters are also examined. PJV/ENV 1/10 ES-6

10 2009 PJV Annual Environmental Report Executive Summary Bed sediment results for arsenic concentrations in the finer <63µm size fraction showed a higher concentration of arsenic-bearing sediments in the southern region of the lake, with a downward progression heading north. This trend has resulted from arsenicbearing fine particulates entering Lake Murray from the Strickland River during reverse flows in the Herbert River. In contrast to arsenic, bed sediment results for mercury concentrations for the <63µm fraction were at or below the detection limit. Bed sediment results for other trace metals in the <63µm fraction varied considerably although copper, lead, nickel, silver and zinc showed higher concentrations in the southern end of the lake similar to arsenic. Iron and selenium showed lower values in the south while chromium showed no distinct trend. Cadmium concentrations were all at or below the detection limit. Bed sediments in the total size fraction showed higher concentrations of arsenic, copper, lead, nickel and zinc in the southern end of the lake. Chromium and selenium showed lower values in the southern end while chromium showed no distinct trend. Cadmium, mercury and silver values were at or below their respective detection limits. For water quality in Lake Murray, the concentrations of all dissolved metals except iron and zinc were at or below their respective detection limits. Iron showed no distinct trend while zinc showed a slight decrease in concentrations from north to south. Similarly, total concentrations for all the relevant metals, except iron, nickel and zinc were at or below their respective detection limits. Total zinc concentrations showed an obvious decrease from north to south while decreases for iron and nickel from north to south were slight. The analyses for sulphate showed a slight increase from north to south. The ph values showed no distinct trend, with all median results being slightly acid, ranging from 6.0 to 6.5. Chloride concentrations showed a slight decrease from north to south. Biological Monitoring The aims of the biological programs are twofold. Firstly, they provide specimens for tissue trace metal analyses that are useful for bio-monitoring and human metal intake studies via aquatic food consumption. Secondly, they generate data to assess changes in the species richness, abundance and condition state of health of fish, and some invertebrates, that may have resulted from mining activities. The sampling sites are divided into three sections: the Upper Catchment section Lagaip River at Wankipe and Wasiba, the Ok Om at Sisimin, and the Kuru and Pori Rivers; the Lowland Strickland section Strickland River at Bebelubi and Tiumsinawam, the Tomu River, Baia River and SG5; and the Lake Murray section at Maka, Pangoa and Miwa. SPECIES RICHNESS, ABUNDANCE AND CONDITION In the upper catchment, there was no evidence to suggest any mine-related impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year 2009, nor in rank correlation assessments of trends over the extent of available data between 2000 and 2009 at each site except for at Wasiba where a declining trend was detected for prawn numbers and biomass from 2000 to Standardised sampling is not currently undertaken at the reference sites at Kuru River and Pori River due to the lack of suitable sandbanks to perform seine netting. It is planned that during 2010 backpack electrofishing will be implemented at all upper catchment sites to increase the PJV/ENV 1/10 ES-7

11 2009 PJV Annual Environmental Report Executive Summary likelihood of achieving sample numbers for tissue collection and to give another standardised method to measure species richness, abundance, diversity and biomass. At lower Strickland River sites standardised gill and seine netting did not suggest any mine-related impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year There were no unmatched decreasing trends detected at sites downstream of the mine within the time period 2000 to Hydroacoustic sampling at lower Strickland off river water bodies and Lake Murray was undertaken in In 2009, fish density at Avu was found to be significantly greater than that observed at Maka, although it is thought that this was partly an artefact of the large amount of floating macrophyte racks at Avu. For the oxbow lakes, Levame, Oxbow 3 and Zongamange, no significant differences in fish density were detected. A comparison of fish density between sampling in 2008 and 2009 at each site detected significant differences for Avu, Maka and Zongamange. At Avu and Zongamange, fish density was found to have significantly decreased in 2009 when compared with data from 2008 while at Maka fish density observed in 2009 was significantly greater than that seen in While differences have been detected, the use of hydroacoustic sampling is still in its early stages and further years of sampling will be needed for full understanding of the natural variation that would be expected to be seen at these sites. Specimen condition in the upper catchment indicated a significant difference for the prawn M. handschini at Wasiba when compared with prawns collected at Pori River, indicating a possible mine-related effect. This trend was not observed between Wasiba and the other reference sites at Ok Om or Kuru River but should be closely monitored throughout 2010 monitoring. Spearman s rank correlations indicated that there were no significant decreasing trends for N. equinus or M. handschini at sites downstream of the mine within the time period 2000 to The condition of fish and prawns at lower Strickland River sites was not found to be significantly different between sites downstream of the mine and reference sites. However, a significant decreasing trend in the condition of P. macrorhynchus collected at Tiumsinawam was detected over the time period 2000 to TISSUE METAL CONCENTRATIONS Laboratory based quality assurance was acceptable for samples analysed in Quarters 2, 3 and 4, while laboratory duplicate samples in Quarter 1 where outside the required relative percent difference RPD values for arsenic, copper, chromium, mercury and nickel. The use of field blanks was a great improvement over recent years and the biological team should be commended for this effort. A total of 31 field blanks were used in 2009, a major improvement on 2008 where only seven field blanks were used. The analysis of the field blanks indicated that some contamination of samples is occurring during sample processing and possibly during sample preparation at the analytical laboratory. A review of sample processing during 2010 is recommended. The results of the field blank analysis indicated that a greater margin of error should be associated with the samples analysed in 2010 and the subsequent tissue metals analysis. PJV/ENV 1/10 ES-8

12 2009 PJV Annual Environmental Report Executive Summary Tissue sampling of target organisms was undertaken at all planned sites in 2009, except at Lake Murray where landowner intervention and unreasonable compensation demands prevented sampling for tissues from occurring. Sampling at sites in the Lower Strickland continued at the expanded number of sites which commenced in 2008 with both Bebelubi and the reference site at Baia River sampled for the fourth year in a row with plans to increase sampling at these sites from biannual to quarterly. The extent of mine-related and in some cases anomalous elevation of metal bioaccumulation is discussed in detail for each metal in Section 7.2 of this report, Tissue Metal Concentrations. The results of tissue metals analysis for samples collected in 2009 indicated that the patterns of elevation of metal bioaccumulation in the Lagaip River and the lower Strickland River region reported in previous editions of the Annual Biology Report has persisted. Significantly elevated concentrations of cadmium and lead have continued to be detected in prawn cephalothorax right down to SG5. For cadmium this pattern has remained in samples. Overall, these results demonstrated the persistence of the patterns of elevation and of metal bioaccumulation in the Lagaip River that had been reported previously and that the elevation of bioaccumulation of cadmium has continued to be widespread in the lower Strickland. Elevated bioavailability of arsenic was observed as far down the river system as SG5 in both prawn cephalothorax and flesh samples, while for mercury this was observed in both fish flesh and liver only at Bebelubi in the lower Strickland. While an increase in the prevalence of some metals and metalloids throughout the catchment can be inferred from the tissue metal concentration results, the contamination that was detected in the field blank samples needs to be taken into consideration. Concentrations of copper, zinc, selenium and mercury were found to be outside the acceptable quality assurance limits of the field blanks from each quarter. Therefore, the interpretation of the results needs to make allowance for this increased margin of error. Taking this into account the results of the tissue metals analysis were very similar to the results from 2007 and The results of the tissue metal concentrations for each tissue type and organism type were screened against the lowest observed concentration co-occurring with an effect LOEC from the effects database of Jarvinen and Ankley Sites where the ratio of results above:below the corresponding effects threshold for impact sites was found to be greater than for any of the corresponding reference sites where found at all impacted sites down to Tiumsinawam for cadmium in prawn cephalothorax and fish liver and also for mercury in fish liver and zinc in fish flesh. The use of literature LOEC values as a screening tool for the risk of adverse biological consequences of the observed patterns of metal bioaccumulation suggests that it was not possible to conclude that there was little risk of adverse consequences at least, as far downstream as the Strickland River at Tiumsinawam. However, this approach is at best an initial screen of potential risk and cannot be used to conclude that there is increased risk. A dedicated effort to collect prawns from the upper catchment for serum sorbitol dehydrogenase enzyme SDH marker analysis was undertaken in the 3 rd quarter of Samples were collected from the impacted sites in the Lagaip River at Wasiba and Wankipe and at the reference sites at Ok Om and Pori River. The results of the analysis on the prawn abdomen indicated significantly p=0.001 elevated hepatic cell PJV/ENV 1/10 ES-9

13 2009 PJV Annual Environmental Report Executive Summary damage in prawns collected from Wasiba and Wankipe when compared with prawns from the reference sites. This result is similar to that detected in 2006 where prawns from the impacted sites at Wasiba and Wankipe where observed to have increased levels of SDH compared with reference sites. It is not known whether the amount of hepatic cell damage reflected by these increased concentrations of SDH is tolerable by the prawn species sampled. Investigations into the relationship between these levels of SDH in the prawn abdomen and organism health would allow for a better understanding of the state of the population in the upper catchment. During 2010, the continuation of the SDH program in the upper catchment and the inclusion of sites in the lower Strickland region will further enhance the biological biomonitoring programs power to detect impacts at the population level before detrimental damage at the population level occurs. During 2009, a PhD project commenced with the aim to investigate the mechanisms for elevation of bioavailability of metals in the lower Strickland region. The project, run in partnership with CSIRO and Hydrobiology, will attempt to form an understanding of the mechanism of trace metal bioaccumulation, and whether or not this can be managed. Rehabilitation and Closure The total area disturbed by PJV operations at the end of 2009 was 1,443ha PJV Mine Dept. The increase since December 2006 was mainly due to the expansion of the waste rock dumps. The main focus of work in 2009 was continued revegetation of the Kogai stable dump. To date, 85% of the Kogai has been stabilised with ground cover establishment, with the remaining 15% used for operational purposes such as haul roads and stockpiles. A total of 15,358 tree seedlings, supplied by both contractors and raised from the environment nursery, was planted on the Kogai stable dump. Most were planted as replacements for dead trees and those uprooted by illegal miners and those that were suppressed by Desmodium grass. Erosion controls such as erosion bunds and silt traps were constructed on the Kogai and Anawe stable dumps while those constructed previously were desilted. The total competent waste rock in 2009 was approximately 12.3M tonnes. Competent waste rock was used for roads, sheeting and buttressing, with the remainder being placed at either the Kogai K80 or Anawe North stable dumps. Incompetent erodible waste rock to the two erodible dumps totalled 14.5M tonnes with Anawe receiving more than 8.7M tonnes in The erosion trial showed that rip rock slope battering and contouring grass seed mix at 1 metre intervals had the highest erosion rates over the four months. The best method of minimizing erosion on the slope was hand broadcasting grass seed mix with fertiliser DAP at 600kg/ha. Various shallow-rooted food crops, including sweet potato, cabbage, broccoli and beans were tested under different mine soil types for metal absorption. The results showed much variation and will be replicated again before reporting the findings in next year s 2010 report. PJV/ENV 1/10 ES-10

14 2009 PJV Annual Environmental Report Table of Contents Table of Contents Page Executive Summary ES Introduction Hydrology and Sediment Transport 2-1 Summary Introduction Major Tasks Undertaken during Year Instrumentation Upgrade Rating Curves Data Recovery Hydrometeorological Data Meteorology at Porgera Rainfall Summary of Stations in Strickland Catchment River Flows River Profiling Sediment Transport Issues and Fate of Sediment Hydrological Context Sources of Sediment Inputs Status of Erodible Dumps Riverbed Aggradation Sediment Transport Tailings Monitoring 3-1 Summary Introduction Methods Results and Discussion Arsenic Cadmium Chromium Copper Iron Lead Mercury Nickel Silver Zinc Cyanide Concentrations in Tailings ph in Tailings Total Suspended Solids TSS in Tailings 3-29 PJV/ENV 1/10 i

15 2009 PJV Annual Environmental Report Table of Contents Table of Contents cont Page 4.0 Compliance Monitoring 4-1 Summary Introduction Methods Trace Metals and Other Parameters Arsenic Cadmium Chromium Copper Iron Lead Mercury Nickel Silver Zinc Other Water Quality Parameters Free Cyanide Ammonia Sulphide Sulphate ph Measurement Sewage Treatment and Drinking Water Treatment Sewage Treatment Plant Analyses Drinking Water Treatment Analyses Permitted Waste Discharge Quantities Permitted Abstraction Quantities Quality Assurance / Quality Control QA/QC Introduction Data Analysis River Monitoring 5-1 Summary Introduction Trace Metals in the Downstream River System Arsenic in the River System Cadmium in the River System Chromium in the River System Copper in the River System Iron in the River System Lead in the River System Mercury in the River System Nickel in the River System Silver in the River System Zinc in the River System Physicochemical Parameters in Downstream River System ph Measurement 5-36 PJV/ENV 1/10 ii

16 2009 PJV Annual Environmental Report Table of Contents Table of Contents cont Page TSS in the River System Bed Sediment Sampling in the Downstream River System Local Creeks Water Quality Monitoring Quality Assurance / Quality Control QA/QC Introduction Data Analysis Lake Murray 6-1 Summary Introduction Methods Results Bed Sediments Water Quality Biological Monitoring 7-1 Summary Species Richness, Abundance and Condition Tissue Metal Concentrations Quality Assurance Temporal and Spatial Variation Recommendations Rehabilitation and Closure 8-1 Summary Introduction Progressive Rehabilitation Disturbed Areas Erosion Controls Progressive Revegetation Nursery Production Wood Chip Production Waste Rock Monitoring Waste Tonnages to Dumps Trials and Research Erosion Trial Erosion Trial Results Testing food crops for metal uptake in mine soil types 8-10 Appendix 1 Box Plots A1-1 Appendix 2 Biological Monitoring Technical Report A2-1 PJV/ENV 1/10 iii

17 2009 PJV Annual Environmental Report Table of Contents List of Figures Page 2-1 Location of environmental monitoring stations Overall data recovery at the monitoring stations Summary of Anawe weather station data Annual rainfall at Anawe plant site since Monthly rainfall at Anawe during 2009 against long-term average Annual rainfall at Open Pit since Rainfall at Open Pit during 2009 against long-term monthly means Rainfall and average dam level at Waile Creek Dam during Rainfall at Pongema during 2009 against long-term monthly means Rainfall at SG2 during 2009 against long-term monthly means Rainfall at Ok Om during 2009 against long-term monthly means Rainfall at SG3 during 2009 against long-term monthly means Rainfall at SG4 during 2009 against long-term monthly means Rainfall at SG5 during Comparison of long-term rainfall at sites in Strickland catchment Instantaneous daily flows at SAG Mill, Culvert and Pongema for Instantaneous daily flows at SG2, Ok Om and SG3 for Daily total flows at the SG3 compliance site for Flow at SG2 during Daily flow comparison between SG3 and SG4 for Profile comparison at SG Profile comparison at Profile Profile for Kaiya River downstream of Kogai confluence Profile for Kaiya River upstream of Yuyan bridge Profile for Kaiya River downstream of Yuyan Bridge Five-year means of annual rainfall at Anawe weather station Frequency of storm types over time at Anawe Comparison of annual flow volumes for main river gauging stations Mean annual specific yield for main river gauging stations Yearly spoil placed at Anawe since July 1989 tonnes Yearly spoil placed at Anjolek since July 1992 tones Total and cumulative tailings & waste rock sediment inputs to date year running means of dump rate Comp of rainfall totals & erodible dump placement rates, 5-year period Estimated rate of bed buildup at Yuyan bridge using historic photos Time series of minimum measured bed elevation, SG Time series of minimum measured bed elevation, PF Estimate of tailings and waste rock export from erodible dumps Relation between depth-integrated and gulp TSS at SG3, SG4 & Ok Om Variation of TSS for different flow rates full period of record Mean annual TSS values at key stations Measured & predicted suspended sediment for 2009, selected stations Estimated suspended sediment budget at SG3 since Estimated suspended sediment budget at SG3 as percentages A/B Boxplots of dissolved and total arsenic at SG A/B Boxplots of dissolved and total cadmium at SG3 4-5 PJV/ENV 1/10 iv

18 2009 PJV Annual Environmental Report Table of Contents List of Figures cont Page 4-3A/B Boxplots of dissolved and total chromium at SG A/B Boxplots of dissolved and total copper at SG A/B Boxplots of dissolved and total iron at SG A/B Boxplots of dissolved and total lead at SG A/B Boxplots of dissolved and total mercury at SG A/B Boxplots of dissolved and total nickel at SG A/B Boxplots of dissolved and total silver at SG A/B Boxplots of dissolved and total zinc at SG A/B Boxplots of dissolved ammonia at SG A/B Boxplots of sulphate at SG A/B Boxplots of ph at SG Shewart control charts for SG A/B Arsenic concentrations at downstream monitoring sites C Dissolved arsenic mean annual concs at downstream sites A/B Cadmium concentrations at downstream monitoring sites C Dissolved cadmium mean annual concs at downstream sites A/B Chromium concentrations at downstream monitoring sites C Dissolved chromium mean annual concs at downstream sites A/B Copper concentrations at downstream monitoring sites C Dissolved copper mean annual concs at downstream sites A/B Iron concentrations at downstream monitoring sites C Dissolved iron mean annual concs at downstream sites A/B Lead concentrations at downstream monitoring sites C Dissolved lead mean annual concs at downstream sites A/B Mercury concentrations at downstream monitoring sites C Total mercury mean annual concs at downstream sites A/B Nickel concentrations at downstream monitoring sites C Dissolved nickel mean annual concs at downstream sites A/B Silver concentrations at downstream monitoring sites C Dissolved silver mean annual concs at downstream sites A/B Zinc concentrations at downstream monitoring sites C Dissolved zinc mean annual concs at downstream sites ph measurements at downstream monitoring sites Metal content of < 63µm & Total fractions of bed sediments Local Creek Monitoring Stations Results for dissolved metals in local creeks Results for total metals in local creeks Physicochemical parameters of local creeks Shewart control charts for tailings, local creeks and downstream Sediment and water quality sampling locations within Lake Murray Between site arsenic concs. in sediment <63µm, Lake Murray Between site mercury concs in sediment <63µm, Lake Murray Between site metal concs in sediments <63µm, Lake Murray Between site total metal concs in sediments, Lake Murray Between site dissolved metal concs for water, Lake Murray PJV/ENV 1/10 v

19 2009 PJV Annual Environmental Report Table of Contents List of Figures cont Page 6.7 Between site total metal concs for water, Lake Murray Between site ph, sulphate & chlorides, Lake Murray Cadmium concentrations, various cephalothorax, liver & flesh samples Lead concentrations, various cephalothorax, liver & flesh samples Arsenic concentrations, various cephalothorax, liver & flesh samples SDH analysis results of prawns from various sites, upper catchment K80 dump surface area extension K71 semi-competent dump reclaimed by mine operations Erosion trial plot design Monthly erosion with various methods on K62 slopes Particle size distribution 8-11 List of Tables Page 2-1 Data % recovery from continuously recording stations last 5 years Summary of 2009 meteorological data at Anawe Plant site Rainfall summary at Anawe plant site since Summary of mean daily flows for riverine stations during Summary of mine inputs to river system during Previous estimates of particle size distribution of dump-toe material Summary of long-term dump mass balance from survey data Estimate of mine-derived suspended sediment for A Summary for dissolved and total arsenic in tailings for B Summary statistics for dissolved and total arsenic since A Summary for dissolved and total cadmium in tailings for B Summary statistics for dissolved and total cadmium since A Summary for dissolved and total chromium in tailings for B Summary statistics for dissolved and total chromium since A Summary for dissolved and total copper in tailings for B Summary statistics for dissolved and total copper since A Summary for dissolved and total iron in tailings for B Summary statistics for dissolved and total iron since A Summary for dissolved and total lead in tailings for B Summary statistics for dissolved and total lead since A Summary for dissolved and total mercury in tailings for B Summary statistics for dissolved and total mercury since A Summary for dissolved and total nickel in tailings for B Summary statistics for dissolved and total nickel since A Summary for dissolved and total silver in tailings for B Summary statistics for dissolved and total silver since PJV/ENV 1/10 vi

20 2009 PJV Annual Environmental Report Table of Contents List of Tables cont Page 3-10A Summary for dissolved and total zinc in tailings for B Summary statistics for dissolved and total zinc since A Summary for cyanide forms in tailings for B Summary statistics for cyanide concs in tailings A Monthly ph values in tailings for B Summary statics for ph values in tailings A Monthly TSS in tailings for 2009 % B Summary statistics for TSS in tailings Summary statistics for dissolved and total arsenic at SG3 since Summary statistics for dissolved and total cadmium at SG3 since Summary statistics for dissolved and total chromium at SG3 since Summary statistics for dissolved and total copper at SG3 since Summary statistics for dissolved and total iron at SG3 since Summary statistics for dissolved and total lead at SG3 since Summary statistics for dissolved and total mercury at SG3 since Summary statistics for dissolved and total nickel at SG3 since Summary statistics for dissolved and total silver at SG3 since Summary statistics for dissolved and total zinc at SG3 since Mean monthly trace metal concentrations at SG3 for Mean yearly trace metal concentrations at SG3 since Comparison of 2009 mean dissolved concentrations with guidelines Summary statistics for dissolved ammonia at SG3 since Summary statistics for sulphate at SG3 since Summary statistics for ph at SG3 since Results of sewage treatment plant analyses, Results of drinking water treatment plant analyses, Discharge quantities from Erodible Dumps and Tailings Abstraction Rates from Waile Creek Dam and Kogai Creek Statistical data of certified reference material Mean arsenic concentrations at downstream sites since Mean cadmium concentrations at downstream sites since Mean chromium concentrations at downstream sites since Mean copper concentrations at downstream sites since Mean iron concentrations at downstream sites since Mean lead concentrations at downstream sites since Mean mercury concentrations at downstream sites since Mean nickel concentrations at downstream sites since Mean silver concentrations at downstream sites since Mean zinc concentrations at downstream sites since Mean ph measurements at downstream sites since Mean TSS concentrations at downstream sites since Mean bed sediment metal concs. <63µm downstream since Mean bed sediment metal concs. total fraction downstream since Mean annual water quality data for local creeks Statistical data of certified reference material 5-72 PJV/ENV 1/10 vii

21 2009 PJV Annual Environmental Report Table of Contents 6-1 Metal concentrations in bed sediments at Lake Murray since Water quality at Lake Murray since Disturbed areas in hectares Number of seedlings produced for each species Waste rock tonnages dumped between List of Plates Page 2-1 Changes to the toe of Anjolek dump since Confluence of the Kogai and Kaiya Rivers Bed aggradation at Yuyan Bridge, Kaiya River Erosion bund on Anawe North dump Erosion bund below K71 rubbish dump Silt traps on Kogai dump Erosion bund below A Young pandanas tree on K62 rehabilitation site Producing wood chips Mixing soil with wood chips Trial plot with geofabric installed Silt catchment area Hand broad cast treatment Cleaning catchment area 8-9 PJV/ENV 1/10 viii

22 2009 PJV Annual Environmental Report - Introduction 1.0 INTRODUCTION This report has been prepared as a requirement of the Environment Permit WD-L3121 clause 42 and the Environment Permit WE-L391 clause 8, as agreed to between Porgera Joint Venture PJV and PNG Department of Environment and Conservation DEC. The report is in eight sections with two appendices and presents information pertaining to environmental management and monitoring at the Porgera gold mine and in the downstream river system during Section 2 of this report provides 2009 hydro-meteorological and sediment transport monitoring data for the Porgera local region and downstream along the Strickland River system to Lake Murray. This information is critical in assessing other factors including river dilution rates and predictions of material movement and suspended sediment. It also influences the erosion rates of erodible dumps and the total contribution of minederived material, including tailings, to the river system. Rainfall also influences the frequency of landslips and non-mine derived sediment to the river system. Section 3 presents 2009 monitoring data for tailings discharge which contributes both metal-bearing sediment and dissolved metals to the river system. The concentration of dissolved metals in tailings slurry and river dilution rates have considerable influence on the levels of dissolved metals, especially at the compliance point SG3, and in fish and prawns along the river system. The monitoring data also assess the potential effects downstream from Process Plant operational changes that can occur periodically. Section 4 summarises the 2009 SG3 compliance monitoring results at Tumbudu on the Upper Strickland River which marks the end of the tailings mixing zone set by the PNG Government, and it is important for PJV to verify compliance with permit conditions at this location. SG3 marks the end of the tailings and erodible waste rock compensation zone for people living downstream of the mine. Section 5 presents 2009 water quality and sediment results at various monitoring locations from the Porgera region along the Porgera/Lagaip/Strickland River system to upstream of the Fly River junction. Since mining operations began at Porgera in 1990, PJV has operated a comprehensive environmental monitoring program to assess riverine impacts caused by the disposal of tailings and incompetent waste rock from the mine. Section 6 presents 2009 sediment and water quality monitoring data for Lake Murray. Flow reversals from the Strickland River into Lake Murray via the Herbert River enable some mine-derived, metal-bearing sediment to enter the southern end of Lake Murray where deposition can occur. Lake Murray has relatively-high, naturally-occurring levels of mercury within the lake and the purpose of PJV s monitoring was to assess whether the small amount of mercury released from the mine would exacerbate the existing problem. PJV monitoring has confirmed that the mine operations have had no effect on mercury levels within the lake over the past 20 years. Section 7 is a summary report of the 2009 biological monitoring program downstream of the Porgera mine along the Strickland River system, including Lake Murray. The PJV/ENV 1/10 1-1

23 2009 PJV Annual Environmental Report - Introduction monitoring program provides specimens for tissue metal analysis for bio-monitoring and human metal intake studies via aquatic food consumption. The program also assesses potential changes in the species richness, abundance and condition of fish and invertebrates from the mining activities. The full biological report is presented as Appendix 2. Section 8 addresses the progress of rehabilitation and closure planning programs around the Porgera mine site during The programs include progressive landform rehabilitation during the operational phase, as well as progressive revegetation where required, especially on recently-disturbed ground. The closure planning component involves submitting a detailed mine rehabilitation program to the PNG Government five years prior to official shutdown of mining and processing activities. PJV/ENV 1/10 1-2

24 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 2.0 HYDROLOGY AND SEDIMENT TRANSPORT SUMMARY Hydro-meteorological and sediment transport data collection continued during the year at stations within the mine site and on the downstream river system. Overall data recovery was 94%, which is a good improvement from the previous couple of years where recoveries were as low as 75%. Rainfall at the Anawe plant site and Open Pit mine were 11% and 24% above the long-term averages respectively, which was consistent with the pattern at other stations in the upper river system. River flows at all stations were also above longterm averages, as they have been for the last couple of years. Relatively little data pertaining to physical sedimentology were collected during the year due to law and order problems in areas where Hydrology staff were unable to operate, although monthly spot total suspended sediment TSS data were collected by the Chemistry staff. However, four new profile cross sections were established in the Kaiya River for the purposes of monitoring aggradation due to sediment run-out from Anjolek Dump and valley wall erosion. In addition, existing profiles at SG2 and PF10 were re-surveyed adding valuable data to existing, long-term datasets. A review of sediment processes indicated that mine-derived inputs waste rock and tailings were generally low in 2009 compared to historical values. However, measured TSS values in mg/l at key stations along the river system, and the estimated suspended sediment load in Mt/y at SG3 were slightly elevated compared with predicted values and presumably resulted from the combined effect of high flows and a higher-than-normal rate of natural sediment input. Inspections of the erodible dumps and Kaiya, Pongema and Porgera Rivers showed no noteworthy change from the last reporting period. Both dumps appeared relatively stable and there was evidence that the rate of aggradation of the Kaiya River had slowed based on observations at Yuyan Bridge and the Kogai/Kaiya Junction. This was interpreted to mean that the pulse of sediment generated when the toe of Anlolek widened in 2007, had passed through the Kaiya River and had been flushed along the Porgera River. Cross sections undertaken at SG2 and PF10 both showed bed lowering. Four new cross sections were established in the Kaiya River for the purpose of monitoring channel change. Although the export of sediment from the erodible dumps could only be crudely estimated in the absence of monitoring data, it is noted that LiDAR surveys were conducted during the reporting period and it should be possible to undertake dump volume balance calculations in coming years to determine the loss of sediment downstream. Reviews of the 2009 hydrological and sediment transport data and monitoring were carried out by Chris Fink of CF Hydrometrics consultants and Dr Andy Markham of Hydrobiology, respectively. PJV/ENV - 1/10 2-1

25 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 2.1 Introduction Hydrological data are critical to the other environmental studies because they enable assessment of dilution rates and predictions of material and suspended sediment movement. Hydrology also influences erosion rates of erodible dumps and the total contribution of mine derived material including tailings to the river system. Heavy rain also influences the frequency of landslips and non-mine derived sediment to the river system. The rate of river flow has a great impact on total suspended solids in both the upper and lower river. This section overviews the hydro-meteorological and sediment transport data collected during 2009 as part of PJV s environmental management and monitoring program and, at local stations for operational and mine closure purposes. Figure 2-1 shows the key sites along the Porgera-Lagaip-Strickland Rivers system as well as the Ok Om control station. Meteorological data were collected at Anawe mine site meteorology station while rainfall data continued to be collected at either stand-alone stations or in tandem with river flow data collection. Sedimentation data collection during the year involved total suspended solids TSS as well as river profiling in the middle and low reaches only. Hydrology and sediment transport data collected during the year were reviewed by CF Hydrometrics and Hydrobiology consultants, respectively. This Chapter discusses hydrology and sediment transport issues, and data collection and analysis during PJV/ENV - 1/10 2-2

26 Nomad River 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport OK OM RIVER OK OM CONTROL STN Sisimin Wagiba LAGAIP Wankipe SG2 SG3 Tumbudu River Pori River Porgera River Line SG1 PORGERA MINE RIVER OK TEDI Gaiabi Tinahai Transmission Omemi Ok Tedi River Komagato Hides RIVER Baia River KIUNGA Tegena Bebelubi Buseki Upovia Upovia LAKE MURRAY Kukudobi Duale Undugumbi Wikikama Tiumsiniwam Tomu River SG4 FLY Boboa Herbert River STRICKLAND SG6 SG5 SG7 INDONESIA PAPUA NEW GUINEA RIVER SG8 PURUTU DARU GULF OF PAPUA Figure 2-1 Location of environmental monitoring stations PJV/ENV - 1/10 2-3

27 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 2.2 Major Tasks Undertaken during Year Law and order problems and tribal conflicts prevented many activities outside those required for compliance and licensing requirements. Some EMP activities i.e. cross section profiling along the Porgera River were not possible due to personal safety concerns Instrumentation Upgrade The phased program of monitoring equipment renewal was continued throughout 2009, with the replacement of aged and dated instrumentation at the Anawe weather station, Lapaip River at SG2, Ok Om at Sisimin, Strickland River at SG4 and SG5. All instrumentation logger, level sensor, solar and gas purge systems, etc. were replaced using modern, reliable technology that should last until 2015 and beyond. The satellite telemetry system is still in place, though is proving temperamental and requires updating in the near future, which would be an add on to the new equipment. Most sites are also fitted with backup logging capabilities for rainfall and water level. It is planned to complete the update in The new equipment is more flexible in its capabilities and expansion facilities than the current superseded and failing instrumentation. With the telemetry system in place, early warning of potential and existing problems can assist in minimizing data loss and/or deterioration in quality of the data Rating Curves Rating curves for key stations have been maintained throughout the year, with most sites receiving sufficient calibration checks gaugings to validate ratings. There is evidence of degradation scour of the bed level at SG2 below Lapaip - Porgera confluence, which would indicate, either that mine derived heavy sediments are concentrating in the Porgera River itself although this can t currently be checked due to inability to survey profiles due to unrest, or the above average rainfall and flows over the last four years is causing bedload to be carried further downstream to the flatter grades of river below SG2. There was however no evident change in ratings aggradation or degradation at the major riverine sites below SG2. New ratings where generated for the Kogai at Culvert bridge site, because of reengineering of the channel and at SG2 on the Lagaip due to a gradual scour of the channel profile by some 30cm over the last four to five years Data Recovery The overall data recovery rate of 94% during the year was a good result and above the notional target of 92% refer Table 2-1 and Figure 2-2 over. Generally, good data recovery was achieved at the main riverine stations with the majority of data loss attributable to ongoing vandalism and instrumentation failures. The instrumentation upgrade is having a marked effect on improved recovery and minimizing preventable data loss. Landowner issues still impact on data capture and need to be resolved to further improve and stabilize recovery rates, though current rates are extremely pleasing for a monitoring network in an extreme and isolated environment. PJV/ENV - 1/10 2-4

28 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Table 2-1 Data recovery % from continuously recording stations for previous 5 years Station Variable Comments 2009 data Open Pit Rainfall Waile Creek Rainfall Adit weir Water level poor quality data Kogai SAG Mill Water level Yunarilama Water level logger failure / CA issues Kogai-Culvert Water level logger failure Pongema Rainfall Water level logger failure SG2 Rainfall logger failure Water level Ok Om Rainfall Water level flood damage, etc. SG3 Rainfall Water level SG4 Rainfall Water level logger failure vandalism / theft SG5 Rainfall Water level river bank failure / instrument Anawe All climatic logger failure variables Overall Recovery Rate % Figure 2-2 Overall data recovery at monitoring stations previous 5 years PJV/ENV - 1/10 2-5

29 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 2.3 Hydrometeorological Data Meteorological data continued to be collected during the year at stations around the mine site and along the river system Meteorology at Porgera Meteorological data collection at Anawe plant site are a combination of time-based daily read data and continuous logger data rainfall, temperature, humidity and wind vectors, barometric pressure and solar radiation. The parameters monitored include rainfall, temperature maximum, minimum, dry and wet bulb, evaporation, wind speed and direction, wind run and sunshine duration. Table 2-2 and Figure 2-3 give a summary of the meteorology data collected during the year. From Table 2-2, daily maximum temperature range was 16 o C to 26 o C, while the daily minimum range was 7.8 o C to 23 o C with a daily mean of 15 o C. Minimal seasonal variability occurs throughout the year at Porgera. Table 2-2 Summary of meteorological data for 2009 at Anawe Plant site Parameter Yearly total 2009 Daily high Daily low Daily mean 2009 Long-term daily mean Max Temp o C Min Temp o C Mean Daily o C Sunshine hr 1, Evaporation mm 1, Wind Run km 15, Cloud cover is heavy over the Porgera valley and is mainly influenced by orographic effects. Sunshine hours for the year ranged from 0 to 9 hours with the daily average being 4.0 hours against long-term daily mean of only 3.7 hours. Evaporation at Porgera is relatively low compared to other parts of the highlands. The total evaporation of 1,042mm during the year was equivalent to about 25% of total rainfall 4,119mm. The long-term annual average evaporation is 952mm. As a contrast, evaporation in the lowlands of PNG is in the order of 2,300 to 2,400mm per annum McAlpine et al, Winds are low in the shelter of the Porgera valley and generally prevail from an easterly direction. There is minimal seasonal variation in wind direction, which is mainly katabatic drainage flow in nature. Total wind run during 2009 was equal to 15,925km an average of 0.5m/s. Daily wind run maximum 110km and wind speeds maximum gust of 4.8m/s recorded in the Porgera valley are highly variable and attributed to orographic related to increasing topography influence. PJV/ENV - 1/10 2-6

30 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 'Anawe' Automatic Weather Station Wind Run below 3m in Kilometres Period 1 Year Plot Start 00:00:00_01/01/2009 Interval 1 Day Plot End 00:00:00_01/01/ Rainfall Millimetres /03/ /06/ /09/ Dry Bulb Temperature Ambient Degrees Celsius Rainfall mm. Total /03/ /06/ /09/ Relative Humidity Percent Dry Temp. Deg.C Maximum Minimum :20_30/10/ :20_16/09/ /03/ /06/ /09/2009 Humidity % Maximum Minimum Evaporation from a U.S. Class A Pan Millimetres 20:40_28/05/ :40_16/09/ Evap.[US] mm. Total /03/ /06/ /09/ Figure 2-3 Summary of Anawe Plant site Pandadaka weather station data Note variation between Anawe daily read rainfall and the automatic station is due to resolution differences 0.2mm versus 0.5mm respectively. To maintain consistency with historical data, the daily read rainfall data is utilized for all analysis except short term intensities Rainfall Rainfall stations are either stand-alone or water level-combined data loggers with secondary logger backup. Additional data backup is provided by the telemetry system at equipped sites. Anawe Plant Site The historical rainfall at Anawe is shown in Figure 2-4 and Table 2-3. From Figure 2-4, there is little variability between the years with 1982, 1990 and 1997 being the driest years. The 5 wettest years on record with annual totals exceeding 4,000 mm were 1977, 1983, 1995, 2005 and The highest annual rainfall was 4,413mm in 1977 with the maximum daily rainfall on record being 89mm in August 1990 ARI of 1:10. The maximum daily rainfall for 2009 was 60.8mm on 21 st April and the maximum 6 minute intensity of 10.0mm was during the night of 13 th October. The highest hourly intensity was 32mm on 28 th May. Figure 2-5 shows rainfall at Anawe during the year against long-term monthly averages. Total rainfall of 4,119mm on 321 wet days was 10% above the long-term annual average rainfall of 3,730mm. From the long-term pattern, January to April and October are generally the wettest months in Porgera. PJV/ENV - 1/10 2-7

31 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Rainfall mm Years Annual Long-term Mean Figure 2-4 Annual rainfall at Anawe plant site since 1974 Rainfall mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2009 Long-term Mean Figure 2-5 Rainfall at Anawe plant site during 2009 against long term monthly means PJV/ENV - 1/10 2-8

32 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Table 2-3 Anawe Rainfall Summary since 1974 mm Mean Annual Year Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Monthly Total Max. Year Mean Mean Max Max Min Min % Dev Long Term Monthly Average: Wettest Year: 4413 mm in 1977 Long Term Annual Average: 3732 Dryest Year: 2505 mm in 1997 PJV/ENV - 1/10 2-9

33 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Open Pit Rainfall Rainfall data collection at this station commenced in Figure 2-6 shows the historical data over the years since 1988 with the wettest years having totals above 4,000 mm being 1989, 1995, 1999, 2000, 2003, 2005 and The annual longterm average of 3,713mm at the Open Pit gauge compares well with the Anawe plant site value of 3,730mm, the two stations being in close proximity, though quite different exposure conditions Rainfall mm A n n u a l L o n g -t e rm M e a n Figure 2-6 Annual rainfall at Open Pit since Rainfall at the Open Pit during 2009 compared to long-term monthly averages is shown in Figure 2-7. Total annual rainfall of 4,610mm during the year was 24% above the annual average of 3,713mm. The March monthly rainfall of 474mm was the highest for the year. The maximum daily rainfall was 87.5mm on 4 December, while the highest intensity storm of 11.5mm in 6 minutes occurred on the 27 th August. The highest hourly intensity was 36.5mm on 15 th October. Rainfall mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2009 Long-term Mean Figure 2-7 Rainfall at Open Pit during 2009 against long term monthly means PJV/ENV - 1/

34 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Waile Creek Rainfall and Reservoir Level Figure 2-8 shows monthly rainfall and the average reservoir water levels at the Waile Creek dam during the year. Total annual rainfall of 3,279mm mean daily of 9mm during the year was 16% above the annual average of 2,830mm. The February monthly rainfall of 355mm was the highest for the year while December recorded the lowest monthly rainfall of 170mm. The maximum daily rainfall was 39.5mm on 8 th June 2009, with the highest intensity being 11mm in 6 minutes on 12 th April. Highest hourly intensity was 25.5mm also on 12 th April. The reservoir exceeded 91% full 700ML for 90% of the time. The maximum level in January was 2.08m above spillway, i.e. equivalent to 770ML 102% full, and in November the level dropped to 0.47m, equivalent to 590ML or 75% of capacity. Rainfall mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Dam level above old spillway m Rainfall Dam level Figure 2-8 Rainfall mm and average dam level m at Waile Creek Dam during 2009 Pongema River Rainfall Figure 2-9 shows Pongema Suyan rainfall during 2009 against long-term monthly averages. Total annual rainfall of 3,577mm during the year is compared to a full year long term annual average of 2,990mm. February monthly rainfall of 488mm was the highest for the year. The maximum daily rainfall was 78mm on 3 rd August, with the highest intensity storm being 10.5mm in 6 minutes on 7 th January. The highest hourly intensity was 47.5mm also on 7 th January. Figure 2-9 Rainfall at Pongema during 2009 against long term monthly means PJV/ENV - 1/

35 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Lagaip River at SG2 Rainfall Figure 2-10 shows monthly rainfall at SG2 during the year against long-term monthly averages. Total annual rainfall of 2,717mm during the year 16 days missing is compared to a full year annual average of 1,912mm. The September monthly rainfall of 270mm was the highest for the year. The maximum daily rainfall was 55.5mm on 5 th June 2009, as was the highest intensity storm of 10mm in 6 minutes and the highest hourly intensity of 35.5mm. Rainfall mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2009 Long-term Mean Figure 2-10 Rainfall at SG2 during 2009 against long term monthly means Ok Om Control Station Rainfall Figure 2-11 shows monthly rainfall at Ok Om during the year. The total annual rainfall of 1,954mm during the year is comparable to an annual average of 2,096mm. The February monthly rainfall of 277mm was the highest for the year while May recorded the lowest rainfall of 99mm. The maximum daily rainfall was 47.5mm on 17 th January 2009, with the highest intensity storm of 9.5mm in 6 minutes occurring on the 16 th July and the highest hourly intensity of 31.5mm on the 26 th December. Figure 2-11 Rainfall at Ok Om during 2009 against long term monthly means PJV/ENV - 1/

36 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Strickland River at SG3 Rainfall Figure 2-12 shows monthly rainfall at SG3 during the year against long-term monthly averages. Total annual rainfall of 1,832mm during the year was below the annual average of 1,861mm. This correlates with patterns observed at Ok Om and SG2. The February monthly rainfall of 227mm was the highest for the year, with a maximum daily rainfall of 65mm on 4 th December 2009, while the highest 6-minute intensity of 8.5mm fell on the 7 th November, as did the highest hourly intensity of 38mm. Figure 2-12 Rainfall at SG3 during 2009 against long term monthly means Strickland River at SG4 Tomu Figure 2-13 shows annual rainfall during the year and the long term average since station established. Total rainfall recorded during the year at SG4 was 3,395mm pro-rated for 45 missing days compared to an annual average of 3,750mm. The January rainfall of 518mm was the highest recorded for the year. The maximum daily recorded rainfall was 118mm on 31 st December Figure 2-13 Rainfall at SG4 during 2009 against long term monthly means PJV/ENV - 1/

37 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Strickland River at SG5 d/s Lake Murray Figure 2-14 shows annual rainfall during the year for this station which was established in Total rainfall recorded during the year at SG5 was 2,540mm. The 5 year annual mean is 2,048mm. The March rainfall of 407mm was the highest for the year. The maximum daily rainfall was 82mm on 26 th March 2009, as was a storm with an intensity of 11mm in 6 minutes. The highest recorded hourly intensity was 41mm on 22 nd December Figure 2-14 Rainfall at SG5 during Summary of Stations in Strickland Catchment Figure 2-15 shows rainfall at stations in the middle and upper Strickland and indicates that rainfall at the riverine stations SG3, Ok Om and SG2 was lower than the upper catchment stations. The main reason is that these riverine stations are located in the shelter of steep ridges creating rain shadow effects, as well as orographic uplift affecting the upper stations. Conversely, rainfall in the Strickland lowlands tended to be considerably higher than in the upper Lagaip catchment and is probably caused by the orographic barrier of the Muller Range and Mt. Bosavi. 2 Note: Incomplete data set at SG2 Figure 2-15 Comparison of long-term annual rainfall at sites in the Strickland catchment PJV/ENV - 1/

38 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport River Flows The river systems directly impacted by the mine are primarily the Porgera, Lagaip and Strickland rivers. These can broadly be grouped into 3 regions of interest, these being; upper catchment Porgera valley, middle catchment SG2 to SG3 and lower catchment SG3 to lowlands/floodplain. Continuous river flow data were collected at the key stations along the river system and, at local sites within and in the vicinity of the mine site during the year. In general, flows were slightly above average, which is commensurate with rainfall being above average. A summary of river flow data collected at the operational stations during the year is given in Table 2-4, while plots of the main stations are presented in Figures 2-16 to Table 2-4 Summary of mean daily flows for riverine stations during 2009 Station Days lost Max. Daily Mean cumecs Min. Daily Mean cumecs Daily Mean cumecs Long-term Daily Mean SAG Mill Level Culvert Yunarilama # Pongema SG Ok Om SG SG SG # - insufficient data The Local Stations upper catchment Monitoring of flow data at the 28 Level Adit and the Portal are operational requirements for the pit and underground operations, while data from the Kogai stations are used for the Kogai stable waste dump water handling strategies and stability for closure scenarios. Pongema, as a main tributary of the Porgera River downstream of the Tailings outlet is monitored for its dilutory capacity and as a prospective hydroelectric site. Mean daily flows during the year for the SAG Mill Kogai Dump Toe and Pongema sites of 108ML and 807ML respectively were above long-term averages. Figure 2-16 over presents a comparison of flows at SAG Mill upstream extraction point, Kogai Ck. Alipis access road bridge and Pongema for the year. PJV/ENV - 1/

39 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Interval1 Day Plot E nd 00:00_01/01 / K oga S A G M ill M ax & M ind isch arge cum e cs K Culvert M ax & M indischarge cum ecs P ong em a M ax & M ind isch arge cum e cs Jan Feb M ar A pr M ay Jun Jul A ug Sep Oct Nov Dec Figure 2-16 Instantaneous flows daily at SAG Mill, Culvert and Pongema for 2009 Key Downstream River Stations middle catchment The combined flow of SG2 and Ok Om 32% and 13% respectively contribute approximately 45% of the total flow at SG3. The remaining 55% is contributed by intermediate catchments, primarily the Pori and Tumbudu rivers. Figure 2-17 shows a comparison of the mean flows at SG2, Ok Om and SG3 during the year. At SG2, the mean daily flow was 253 cumecs compared to a long term mean of 209 cumecs, while at Ok Om control site mean daily flow was 113 cumecs compared to a long term mean of 126 cumecs. At SG3, the mean daily flow for the year was 792 cumecs 68GL per day compared to a long-term value of 748 cumecs 64GL per day Interval1 Day Plot E nd 00:00_01/01 / S G 2 M ax & M ind isch arge C um e cs O k O m M ax & M ind isch arge C um e cs S G 3 M ax & M ind isch arge C um e cs Jan Feb M ar A pr M ay Jun Jul A ug Sep Oct Nov Dec Figure 2-17 Instantaneous flows daily at SG2, Ok Om and SG3 for 2009 PJV/ENV - 1/

40 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport SG3 compliance site The total flow for the year at SG3 of 24,980Gl was approximately 12% above the long-term average of 22,255GL. February with 2,992GL had the highest monthly flow while December with 1,406GL had the least. Figure 2-18 shows the daily total flows for the year at SG3 while Figure 2-19 shows total monthly flows against longterm monthly averages. 300 Period 1 Year Plot Start 00:00_01/01/ Interval 1 Day Plot End 00:00_01/01/ SG3 'Compliance Site' Daily Discharge Gl Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 2-18 Daily total flows at the SG3 compliance site for 2009 gigalitres Figure 2-19 Monthly flow at SG3 during 2009 PJV/ENV - 1/

41 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Downstream River Stations lower catchment SG4 and SG5 are monitored primarily for flow determination as applicable to the estimation of sediment and metals yields. SG4 data shows higher flow values and higher rainfall than stations in the upper and middle catchments, which is in accord with the PNG Flood Estimation Manual Model for the area. Specific yield i.e. the runoff per unit area for the catchment area contributing to SG4 is also higher than for all upstream gauging stations. In fact the catchment to the compliance point at SG3 only contributes approximately 25% of total flows passing SG4. Figure 2-20 shows the daily flow comparison between SG4 and SG3. Period 1 Year Plot Start00:00_01/01/ Interval1 Day Plot End 00:00_01/01/ SG4 Daily Flow Gl SG3 Daily Flow Gl Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 2-20 Daily flow comparison gigalitres between SG3 and SG4 for 2009 There is however, a relatively small increase in flow between SG4 and SG5. Primary reasons for this being minimal tributary inflow Tomu, Aiema and Herbert Rivers to the Strickland between the two gauging stations, and considerable floodplain storage that would tend to attenuate flood flows. Data recovery and quality continue to be a problem at both sites, with bank instability and vandalism accounting for the majority of losses at these insolated locations. The total flow for the year was 80,200Gl and 99,400Gl for SG4 and SG5 respectively both prorated for missing data, with a mean daily flow of 232Gl and 283Gl respectively. PJV/ENV - 1/

42 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport River Profiling A component of the monitoring program to access the impacts of the mine on locations downstream of the erodible dumps, etc., is the surveying of profiles cross section that are obtained at designated locations to evaluate changes in stream bed levels. Unfortunately over the last few years, it has not been possible to undertake these surveys due to civil unrest issues predominately in the Porgera valley. Profiles have however been possible at SG2 and at the downstream site below SG4, on the Strickland River. Comparisons of these recent surveys with those from past surveys indicate no discernable aggradation deposition at these 2 sites. It can in fact be confirmed that natural degradation scour has occurred at SG2, indicating that any impacts are confined to the Porgera River. As previously mentioned, this degradation at SG2 has necessitated a change in the rating curve and the result that the river has a greater carrying capacity that previously. The following figures illustrate changes at both SG2 and Profile 10 approx. 40km downstream from Tomu / Strickland confluence. Cross Section Plots Site SectID Date Type Section Name /10/2009Profile 20A Lagaip River at Tamako SG /02/2001Profile 0 Lagaip River at Tamako SG R L in metres Chainage in metres Figure 2-21 River profile comparison at SG2 The obvious change in relative level RL is confirmed by a comparable change in the stage-discharge relationship rating curve. PJV/ENV - 1/

43 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Cross Section Plots Site SectID Date Type Name A JAN09 25/01/2009Profile Strickland River at Profile A AUG00 01/08/2000Profile Strickland River at Profile R L in metres Chainage in metres Figure 2-22 Profile comparison at Profile 10 Following observed changes in the Kaiya River below the Anjolek erodible waste dump, 4 new profiles were established in Figures 2-23 to 2-25 below illustrate the current situation within the valley which will be compared to future surveys. Cross Section Plots Site SectID Date Type Name H JUN09 18/06/2009Profile Kaiya River downstream Kogai Creek R L in metres Chainage in metres Figure 2-23 River profile for Kaiya River downstream of Kogai confluence PJV/ENV - 1/

44 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Cross Section Plots Site SectID Date Type Name G JUN09 18/06/2009Profile Kaiya River upstream Yuyan Bridge R L in metres Chainage in metres Figure 2-24 River profile for Kaiya River upstream of Yuyan bridge Cross Section Plots Site SectID Date Type Name E JUN09 19/06/2009Profile Kaiya River downstream Yuyan Bridge R L in metres Chainage in metres Figure 2-25 River profile for Kaiya River downstream of Yuyan bridge PJV/ENV - 1/

45 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 2.4 Sediment Transport Issues and Fate of Sediment This section describes the inputs, transport, storage and fate of mine-derived sediment in the river system based on routine monitoring of sediment processes and visual observations. Routine monitoring included total suspended solids TSS data collection at key locations along the river system Relatively little data pertaining to physical sedimentology were collected during the year, although monthly spot TSS data were collected by the Chemistry Section. However, as previously discussed, four new profile cross sections were established in the Kaiya River for the purposes of monitoring aggradation due to sediment runout from Anjolek Dump and valley wall erosion. In addition, existing profiles at SG2 and PF10 were re-surveyed adding valuable data to existing, long-term datasets. Therefore, reporting for 2009 relied largely on historical trends and inferences from a limited dataset supported by visual observations. Data on the monthly dumping in the erodible dumps, which were compiled by the Mine Department, and the total tailings discharge for the year, are also presented Hydrological Context As previously discussed in the Hydrology section 2.3.2, 2009 was another wet year. Rainfall at the Anawe plant site and Open Pit mine site were approximately 11% and 24% above the long-term averages respectively, with similar patterns recorded elsewhere at stations in the immediate vicinity. While rainfall stations along the Strickland River showed below-average rainfall totals, river flows at most stations throughout the monitoring network were above long-term averages. Figure 2-26 shows mean annual rainfall totals at Anawe for five-year periods since The data show that the recent period recorded the highest 5-year rainfall for the period of record and is also the highest 5-year total for any period of five consecutive years. Therefore, rates of landscape erosion, delivery of sediment to the river network and its transport along the river system were expected to be high for both the 2009 reporting period and the recent five-year period The high rainfall of recent years is also demonstrated in Figure 2-27 which shows a residual mass plot of annual rainfall at Anawe. The plotted lines represent the cumulative deviation of each year s rainfall total from the overall mean of the dataset. To interpret the graph, a downward sloping line represents below-average years, while an upward sloping line represents above average years. This demonstrates that since 1997, rainfall was significantly higher than the period As discussed in last year s Annual Environmental Report, the frequency of both the short and long-duration rainfall types have also increased over recent years as would be expected given the increased rainfall totals of recent years. The frequency of the longer-duration events has increased markedly i.e. proportionally more of the annual rainfall totals for recent years consisted of the longer-duration events suggesting that the frequency of mass failures may have increased also. PJV/ENV - 1/

46 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 4,400 4,200 Rainfall total mm 4,000 3,800 3,600 3,400 3, year mean of annual totals Figure 2-26 Five-year means of annual rainfall totals at Anawe rainfall Station 500 Rainfall Cumulative Deviation from Mean Value mm About-average years Generally below-average years Generally above-average years Figure 2-27 Residual mass plot of rainfall totals at Anawe rainfall Station The trend for recent years for flow discharge at key gauging stations is presented in Figure 2-28, which confirms that flows were high for the reporting period as expected. Data from SG5 station are also presented on Figure 2-29 and show that the most significant downstream increase in discharge generally occurs between SG3 and SG4 refer following section. PJV/ENV - 1/

47 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 140,000 Annual Flow Volume million cubic metres 120, ,000 80,000 60,000 40,000 20, SG2 SG3 SG4 SG5 Figure 2-28 Comparison of annual flow volumes for main river gauging stations. The mean annual estimated specific yield for the main river gauging station is presented in Figure Specific yield is defined as runoff per unit area of contributing catchment. This is calculated separately for each gauging station so, for example, the specific yield for SG3 refers to the amount of water delivered to the river system from the catchment areas between SG2 and SG3, not the entire catchment area upstream from SG3. As described in previous Annual Reports, the specific yield for the contributing catchment between SG3 and SG4 is the highest recorded in the monitoring network. This means that proportionally more water is delivered to the river network between SG3 and SG4. This reflects high rainfall values in this area. Both figures 2-28 and 2-29 show the notable increase in discharge between SG3 and SG4. Historical data indicate that flow between SG4 and SG5 increases by a relatively small amount. Presumably this is partly due to the fact that there is minimal additional inflow to the Strickland between the two gauging stations, apart from the Tomu River which is relatively small compared to the mainstream flow. However, there is considerable floodplain storage between SG4 and SG5 which would affect the water balance between SG4 and SG5 to some degree. Compared with 2008, data for 2009 Figure 2-29 show that while flows at SG3 were similar, flows at SG4 and SG5 were lower than 2008 data. This was likely due to the above average rainfall in the sub-catchments around the mine site, and the below average rainfall in the Lagaip and Strickland River sub-catchments. In terms of sediment transport processes, figures 2-28 and 2-29 suggest that there is a notable increase in the capacity of the river to transport sediment between SG2 and SG4 and, given that there has been no observed aggradation of the river bed downstream of SG1, then aggradation between SG1 and SG4 appears unlikely. However, downstream of SG4 where discharge increases only by a small amount and the slope of the river flattens, deposition of sands and silts may be more likely. PJV/ENV - 1/

48 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 6,000 Mean Annual Specific Yield ML/km2/yr 5,000 4,000 3,000 2,000 1,000 0 SG1 SG2 SG3 SG4 Ok Om Figure Mean annual specific yield ML/km 2 /y for the main river gauging stations In summary, rainfall and flows were, again, above normal for the reporting period and it would therefore be expected that above-average rates of erosion and sediment transport would have occurred Sources of Sediment Inputs As discussed in previous Annual Reports, sediment in the Porgera-Lagaip and Strickland Rivers system is both natural and mine-derived. Natural sediment enters the river through landslides, rock avalanches and other mass failures from the steep terrain, and bank erosion, while mine-derived sediment enters the river system via the tailings and the erodible waste dumps. While input of mine derived sediments can be quantified with some certainty from the known tailings discharge rate and an annual mass balance of the erodible waste dumps, input from natural sources is variable in terms of size characteristic, quantity and timing and can only be estimated. The Porgera area is characterised by high rainfall rates, high rates of tectonic uplift, and high rates of weathering due to rock and soil types. The majority of sediment is likely delivered to the river systems from mass movements landslides and the like rather than by stream bank erosion or by fluvial processes. Saturated colluvium from such mass failures accumulates in channels where it remains mobile, initially moving as earth and mud flows. Ultimately, this material is entrained and transported downstream as sediment load Davies et al PJV/ENV - 1/

49 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Waste Rock and Tailings Inputs Dumping occurred to both erodible dumps during the reporting period. The total for Anjolek was 5,676,800 tonnes. This was 102% of the 2008 value. The total for Anawe was 8,649,740 tonnes. This was 97% of the 2008 value. Total tonnes to both dumps were generally low compared with historical values. Total tailing discharged to the Anawe Dump for 2009 was 5,430,659 tonnes dry solids, equivalent to a mean daily value of approximately 14,879 tonnes. This compared to a value of 16,571 tonnes per day for the 2008 reporting period and represents the eighth highest tailing discharge rate since Summaries of waste discharges are shown in Table 2-5, and in Figures 2-30 to Table 2-5 Summary of mine inputs to the river system during Total for 2009 tonnes Total To Date tonnes Anawe 8,649, ,742,510 Anjolek 5,676, ,643,923 Tailings 5,430,659 84,601,050 35,000, ,000,000 Tonnes per year 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 5,000, ,000, ,000, ,000,000 50,000,000 Tonnes - cumulative 0 0 Anawe Anawe cumulative Figure 2-30 Yearly spoil placed at Anawe since July 1989 values in tonnes PJV/ENV - 1/

50 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 30,000, ,000,000 25,000, ,000,000 Tonnes per year 20,000,000 15,000,000 10,000, ,000, ,000,000 Tonnes - cumulative 5,000,000 50,000, Anjolek Anjolek Cumulative Figure 2-31 Yearly spoil placed at Anjolek since July 1992 values in tonnes Tonnes per year 50,000,000 45,000,000 40,000,000 35,000,000 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 5,000, ,000, ,000, ,000, ,000, ,000, ,000,000 0 Tonnes cumulative Tailings Total from Erodible Dumps Cumulative Total Sediment Input Figure 2-32 Total and cumulative tailings and rock waste sediment inputs to date Dumping rates at Anawe for the past three years have been quite low in comparison with historical values. As the response time of the toe of Anawe to dumping is thought to be damped with respect to upstream loading/dumping i.e. the dump responds slowly, particularly in the toe area, to marked changes in dump rate, the current dump would be expected to be relatively stable due to the relatively low rates of input. PJV/ENV - 1/

51 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Dumping rates at Anjolek have also been relatively low over the past few years with the exception of Anjolek dump particularly the lower tract is thought to respond more rapidly to upstream loading than Anawe. Therefore, the high erosion rates at, and downstream of, the toe, the elevated sediment runout and the widening and aggradation along the Kaiya River observed in recent years were predicted to reduce if dumping rates continue to be low, and this appears to be evident in Figure 2-33 shows 3-year moving averages for dump rates for both Anjolek and Anawe, and shows the general decline of dump rates described above. 35,000,000 30,000,000 Tonnes Per Year Placed in Dump 25,000,000 20,000,000 15,000,000 10,000,000 5,000, Anawe 3-yr moving average Anjolek 3-year moving average Figure year running means of dump rate. The high rainfall of recent years and including the 2009 reporting period would have resulted in higher-than-average rates of sediment delivery to the channel network as previously described, from both natural and mine-derived sources, particularly from the erodible dumps, scouring of valley walls within the dump tracts, and elevated rates of runout from the dumps toes. Figure 2-34 presents a comparison of the 5- year totals for rainfall at Anawe and the amount of waste placed in the erodible dumps. PJV/ENV - 1/

52 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Figure 2-34 Comparison of rainfall totals & erodible dump placement rates, 5-year periods Status of the Erodible Dumps As reported in 2008, an aerial inspection of the Anawe Dump indicated little change since 2007, including the Maiapam spill area and the location of the toe. In fact it appeared that there had been some erosion of the toe based on visual observation only. The lower tract of the dump was well-vegetated and appeared stable. For the Anjolek Dump, significant changes occurred between 2007 and 2008 with widening and build-up in the lower tract near Apalaka as noted by the PJV s Geotechnical Consultant Mr. R. Goldsmith. Inspections undertaken during 2007 and May 2008 showed that the toe of Anjolek dump had changed quite markedly and the rate of coarse sediment export from the toe appeared to be increasing. This was evident from comparative photographs of the toe area that showed increased sedimentation depths Plate 2-1. In particular, the 2008 inspection showed that a low ridge that had previously extended into the channel from the south side below the toe had been inundated with sediment. It was thought that this ridge had previously acted as something of a coarse sediment barrier at the toe of the Anjolek dump. The 2009 inspection showed that these processes had continued with higher rates of sediment runout from the toe of Anjolek than had been observed prior to A helicopter inspection in March 2010 showed that the general geography of the toe area was similar to that observed in 2009 although some widening at the toe area was apparent. Over the past few years the transition between the dump toe and the Kaiya River has become less marked, with the toe flattening, widening and extending into the Kaiya River Plate 2-1. Elsewhere, there appeared to be little change across the dump generally compared with the results of the 2009 inspection, although isolated surface erosion appeared to have occurred as evidenced by terraces along the southern boundary. PJV/ENV - 1/

53 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Plate 2-1 Changes to the toe of Anjolek Dump since March 2005 February 2007 March 2009 March 2010 * Arrow shows the ridge that was present in 2007, but removed in 2008 and absent in the 2009 photo Riverbed Aggradation Once sediment is exported from the toes of the dumps, it is transported downstream by the flow. Coarser particles may settle out on the bed, on bars or on the floodplain from time to time along the river valley. Changes in riverbed level due to sediment deposition are monitored through cross section profiles, which are located along the Kaiya, Pongema and Porgera Rivers and at the main gauging stations. The cross sections along the Kaiya River and Porgera River are particularly important as these are potential sediment runout zones from the dump toes and significant changes to river morphology may be expected if dump movements occur. In the lower river, a single cross section PF10 is located 60km downstream from SG4. Unfortunately, the more extensive historical network of cross sections between the Mine and the Lagaip River has been significantly reduced over the years due largely to inadequate maintenance, land access issues and loss of critical benchmarks due to bank collapse or river aggradation. At the time of writing, profiles in the Porgera River are not being undertaken due to land access issues. However, as previously discussed, four new cross sections have been established along the Kaiya River, and surveys at SG2 and PF10 Strickland R. downstream of Tomu R. were completed. PJV/ENV - 1/

54 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Kaiya River between Anjolek Toe and Porgera River This reach of the Kaiya River has been subject to variable but persistent aggradation and valley widening. Between 2007 and 2009, the changes to the toe of Anjolek Dump described above have resulted increased rates of sediment delivery, aggradation and widening in the downstream reaches of the Kaiya River. Plate 2-2 shows aerial photographs of the junction of the Kogai River and Kaiya River taken in 2001, 2005, 2009 and 2010 respectively, which is a representative site along the Kaiya River between the toe of Anjolek and the Pongema River confluence. Some obvious areas of erosion were noted, in addition to ongoing widening of the Kaiya River in the upstream reach. The flow pattern and sedimentation patterns in the 2005 and 2009 images suggested that a wave of sediment runout was moving downstream from the Anjolek toe area. However, the 2010 photograph showed that there had been little obvious change since 2009 suggesting that the rate of sediment delivery from the toe of Anjolek had reduced. In 2008, the total aggradation at this location was estimated to be about 20 metres by R. Goldsmith of SMEC. Plate 2-2 Confluence of the Kogai and Kaiya Rivers. October 2001 March 2005 February 2009 March 2010 Significant and accelerated widening and aggradation occurred at Yuyan Bridge between 2007 and 2009 as the front of aggradation moved through the Kaiya River. The ongoing sedimentation can be seen in a series of photographs Plate 2-3. Although no surveys were conducted at this location up to 2009, the rate of aggradation was estimated by reference to the dimensions of the Bailey Bridge deck panels, which are approximately 1.6 metres deep, and by assuming that the average PJV/ENV - 1/

55 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport bed level of the channel is 0.5 m below the water surface. In late 2008, the bridge was raised by an unknown amount and the reference was lost. However, the concrete piers highlighted in the 2008 to 2010 photos appeared to be in the same position. The data are plotted on Figure 2-35 which clearly shows the increasing rate of change at this site, which accords with the changes noted at the toe of Anjolek Dump. However, observations during March 2010 indicated that no further aggradation had occurred and, in fact, approximately 0.2 metres of degradation had occurred under the bridge. This notwithstanding, bank erosion is a continual problem and it was noted that the bank and abutment protection works installed during 2008 had all but failed. Although ongoing aggradation and valley wall failures are to be expected along this reach of the Kaiya River, degradation of the bed may indicate that the wave of sediment released from the toe in 2007 has passed through the reach. PJV/ENV - 1/

56 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Plate 2-3 Bed aggradation at Yuyan Bridge, Kaiya River PJV/ENV - 1/

57 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport " # %& % # % Figure 2-35 Estimated rate of bed build-up at Yuyan Bridge using historic photographs. Further downstream, the confluence of the Kaiya River and Pongema River has also changed quite significantly in recent years due to runout from the dumps, and cross sections PF4 and PF5 have become inundated with sediment. Unfortunately, no cross section surveys were conducted in this reach during the reporting period. However, although the elevation of the bed is highly variable, the best estimate is that 3-5 m of aggradation has occurred at these sites and this agrees well with the aggradation observations at Yuyan Bridge. Based on observations at Yuyan Bridge and Anjolek toe March 2010, it seems likely that the rate of aggradation at this site may be slowing. Inspection of this reach by helicopter did not reveal any significant change since a similar inspection in Pongema River between Anawe Toe and Porgera River There were no significant changes noted along this reach compared with the results of the 2009 helicopter inspection. SG1 to SG2 Visual observations by helicopter in March 2010 suggested no significant change had occurred along the upper Porgera River. SG2 to SG4 As previously discussed, a cross section was measured at SG2 during October Results show that the bed lowering that has been observed previously has continued with downcutting of approximately 1.0 m occurring since 1982, for the lowest point RL of the bed. The reason for this downcutting is not known, but it is presumed that the river is incising or rejuvenating towards an equilibrium profile, possibly in response to localized uplift. A similar trend was also observed at profile PF6 Porgera PJV/ENV - 1/

58 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport River near the Tilia River Junction, but no surveys have been undertaken at this site since Further, the down-cutting trend was not observed at PF3 located between SG2 and PF6. Overall these results continue to suggest that no net buildup of mine-derived sediment is occurring in the lower Porgera River and the upper Lagaip River. A time-series of the minimum bed elevation for each survey for SG2 is shown in Figure Minimum RL, SG Assumed RL m Aug-76 Feb-82 Aug-87 Jan-93 Jul-98 Jan-04 Jul-09 Dec-14 Date Figure 2-36 Time series of minimum measured bed elevation, SG2. No net aggradation is expected to occur between SG2 and SG4 which includes the Lagaip River, and the Strickland River through the Strickland Gorge and the upper section of the Strickland River lowlands. The river through these reaches is fast flowing and subject to sediment inputs from many natural landslides. Apart from the gauging cross section at SG3, no cross sections are established between SG2 and SG4. SG4 to Everill s Junction Fly River As the river descends to the lowlands the Fly Platform from the upland areas, the velocity slows and temporary sediment deposition starts to occur in the form of transient gravel and sand bars. Further downstream, floodplain connections become better established and the bed material becomes predominantly sands and silts. A number of cross sections exist in this reach, including PF10 at SG4 60 km downstream from the Tomu River Junction. Two profile surveys were measured at PF10 in January and April A comparison of the minimum bed elevations RLs for all surveys showed a variable temporal pattern, but no clear evidence of ongoing aggradation or degradation Figure The results of Swanson et al, 2008 indicated that there is approximately a 13% longterm loss of total sediment load to the floodplain below this zone. PJV/ENV - 1/

59 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Minimum RL, 60km DS Tomu PF Assumed RL m Dec-99 Apr-01 Sep-02 Jan-04 May-05 Oct-06 Feb-08 Jul-09 Nov-10 Date Figure 2-37 Time series of minimum measured bed elevation, PF Sediment Transport Export of Sediment from Tailings and Erodible Dumps It is assumed that most of the tailings is discharged across Anawe Dump and to the river system. From visual observations, it is known that some tailings are stored in Anawe Dump but the amount is not known. For the purposes of this report, it was assumed that 5% of all tailings discharged are trapped and stored in the dump. It is also known that sediment inputs to the dump tracts also occur from bank erosion and eroded valley walls in addition to the dump tracts, this effect extends along the Kaiya River to the start of the Porgera River. Again, quantities are unknown. In order to estimate the discharge of silt, sand and gravel from the dumps, it is necessary to estimate the particle size distribution for material at the toe of the dump. A number of estimates of this parameter have been made in previous studies and there is considerable variability in the results. This is due to the difficulty of assigning a single grain size distribution to the very large range of particle sizes, and their spatial variability, at the dump toe. A summary of the various estimates of particle size distribution for the combined dump toes is presented in Table 2-6, which also shows the adopted size distribution used for the purposes of sediment transport calculations. Table 2-6 Previous estimates of particle size distribution of dump-toe material Reference Silt Sand Gravel 1. CSIRO review % 27% 15% 2. PJV 1995 samples average 30% 30% 40% 3. Anawe toe 1997 samples average 5% 35% 60% 4. Black Sed. Accelerated Weathering Tests 72% 20% 8% 5. Davies et al % 11% 13% Mean 1, 2, 4 and 5 59% 22% 19% PJV/ENV - 1/

60 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Although previous survey data and mass-balance calculations for the dumps indicated that approximately 50-60% of material input was lost downstream as a long-term average, more recent survey data suggested that this figure was about 20-30% over recent years Davies et al This is less than previously calculated based on older survey data but there remains considerable uncertainty over these estimates. Table 2-7 shows the adopted values for the long-term proportion of dump mass that is transported downstream, and the long-term sediment transport rates for each dump. Regular surveys and ongoing volume-difference calculations are the only reliable way to estimate sediment lost downstream from the dumps. Topographic LiDAR surveys of both dumps commenced during the 2009 reporting period, meaning that updated estimates of sediment lost downstream from the erodible dumps should be available in Although variable from year to year, historical survey data suggest that the long term mean value for loss of mass i.e. export of sediment from the erodible dumps combined is about 12 Mt per year refer Table 2-7. Table 2-7 Summary of long-term dump mass balance from survey data Approximate % of Total Dumped Material Released based on Survey Data Long term mean downstream transport rate Mt/y. Total mass exported downstream from survey data divided by number of years between survey Anjolek Anawe For 2009, the total estimated mine-derived export of sediment from the dumps was computed as 95% of the tailings added to an estimate of the material exported from the erodible dumps for that year. Table 2-8 presents an estimate of the suspended sediment component of the mine-derived sediment load that was discharged to the river system during Suspended sediment is that part of the total sediment load that travels in suspension in the water column but maintains occasional contact with the bed. Table 2-8 Estimate of mine derived suspended sediment for 2009 Source Tailings mill data Erodible Dumps long term mean value used Total Sediment Discharged Mt/y x 0.95 Suspended Sediment Component Mt/y x 0.95 Total Comments Assumes 95% of tailings is transported as suspended load and 5% remains stored in the Anawe Dump Assumes 59% silt fraction travels as suspended load Based on the above information, a year-by-year breakdown of sediment exported from the erodible dumps was made by using annual dumping and tailings discharge data and applying an annual weighting factor for rainfall variability to each year. It should be noted that this breakdown is a very crude estimate based on assumed PJV/ENV - 1/

61 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport annual variability of long-term parameters and supported by very little data. The results are shown in Figure Sediment Load Million Tonnes Period of reliable dump survey Estimated Export of Tailings from Anawe Dump Estimated Total Loss of Sediment less tailings from EWD Figure 2-38 Estimate of downstream tailings and waste rock export from Erodible Dumps. Transport of Sediment along the River System Sediment that is not deposited within the channel or overbank is transported downstream by the flow. Most of the mine-derived sediment that is transported along the river is referred to as suspended load which is that part of the total load that remains suspended in the flow most of the time. Total suspended solids TSS data were collected by the Chemistry Section at key sites throughout the reporting period for the purposes of estimating annual suspended sediment loads at different points in the river system. Over the past few years, correlations between TSS gulp method and TSS depthintegrated method have been established for SG3, Ok Om and SG4 which enable gulp samples taken from the side of the river to be adjusted to be more representative of the true cross section mean TSS value. These correlations are now well established and the only requirement for further depth-integrated samples at these stations will be to verify the existing relations. The established correlations are shown on Figure For 2009, SG3 provided the best overall flow and TSS dataset enabling the annual suspended sediment load to be calculated for that particular location. Annual loads at other stations could not be estimated due to insufficient sample numbers. However, the likely range of sediment load values has been estimated for all stations as a result of ongoing sampling over a number of years, although year-to-year analyses are not possible on these limited datasets. PJV/ENV - 1/

62 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Apart from the main river gauging stations, TSS samples were also taken from a number of local stations, mostly for the purposes of specific project work or mine layout changes. Summary statistics for TSS data are presented in the River Monitoring section of this Annual Report. 10,000 Depth Integrated TSS Value mg/l 1, DI TSS SG4 = Gulp R 2 = DI TSS SG3 = Gulp R 2 = DI TSS Ok Om = Gulp R 2 = ,000 10,000 Gulp TSS Value mg/l SG3 SG4 Ok Om Figure 2-39 Relationship between depth-integrated and gulp TSS at SG3, SG4 and Ok Om There is no clear relation between TSS concentrations and flow rate at any of the gauging stations. This is partly because the discharge of tailings remains relatively constant regardless of flow, and also that the processes of natural sediment delivery to the stream network and its transport once within the stream network are complex, and not driven by flow rate alone. Therefore it is not possible to estimate suspended sediment concentrations based on flow alone. Figure 2-40 shows the median TSS concentration for different flow bands at each of the main downriver gauging stations. For the stations closest to the mine, data show that TSS decreases with flow with the exception of the very highest flows when TSS is again high above a certain threshold. This indicates that for the very highest flows, much greater rates of sediment transport occur due to high rates of river bank and hillslope erosion, and the transport of this and coarser sands and finer gravels in suspension in the upper catchment. For the lower river gauging stations, where flood peaks are more gradual and rates of hillslope erosion lower due to the flatter terrain, such extreme and episodic sediment transport processes do not appear to occur. Rather, TSS values generally decrease with flow rate due to dilution. PJV/ENV - 1/

63 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 9,000 8,000 7,000 6,000 TSS mg/l 5,000 4,000 3,000 2,000 1,000 0 SG1 SG2 Ok Om SG3 SG > Figure 2-40 Variation of TSS for different flow rates full period of record Estimation of Sediment Load for SG3 using Measured Data Annual suspended sediment transport at SG3 was also estimated using actual TSS and flow data and the usual analysis procedure adopted for annual reporting. The method involved calculating daily loads for those days of the year where both TSS and flow data were available. The sum of the total daily loads for these days was then factored up according to the total flow volume for the year as recorded by data loggers. i.e.: Total Annual Suspended Sediment = MDL x LDF/MDF Where MDL = Measured daily load i.e. the sum of the daily loads measured on sampling days, LDF = Total flow volume from logger for the whole year and MDF = measured daily flow volume i.e. total of gauged flows on sampling days. These results were verified using a statistical adjustment to correct for discrepancies arising from irregularly sampled record and continuous record of flow refer CSIRO 1996 for details of this methodology. This method was derived specifically for PJV during the CSIRO 1996 review. Using the above methods, the calculated suspended sediment load for SG3 was 72 million tonnes for the reporting period which was somewhat higher than expected and was assumed to consist mostly of natural sediment. Using this value, the proportion of total suspended sediment load that was mine-derived during the reporting period 2009 at SG3 was estimated to be approximately 14% which compares to a long term mean value of approximately 32%. This latter figure agrees very well with the results of chemical analyses conducted as part of the NSF US National Science Foundation sponsored Margins Source to Sink Research PJV/ENV - 1/

64 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Program which reported that, by using silver and lead as tracers, the proportion of mine-derived sediment was 29% for SG3 and 12-13% for SG4. Insufficient data were collected at other stations for the purposes of computing the total annual suspended sediment loads. As discussed in previous reports, the suspended sediment load is expected to be similar between SG4 and SG5 although flow and sediment transport is complicated in this region due to floodplain storage and transfers. It is estimated that 13% of the river suspended sediment load discharges to the floodplain and in off-river water bodies. TSS data for 2009 show that values were generally the highest since 2004 despite the fact that both river flows and tailings discharged were slightly lower compared with 2008 values and tentatively suggest that the natural sediment inputs were very high Figure Suspended sediment concentration mg/l SG2 SG3 SG4 Figure 2-41 Mean annual TSS values at key stations Overall Summary An overall summary of the sediment suspended sediment results for 2009 is presented in Figure Suspended sediment loads were estimated based on longterm historical data. For SG3 only, it was also possible to estimate the annual sediment load based on collected TSS and flow data. It was not possible to apply this calculation to the other stations due to insufficient TSS data being collected over the reporting period. PJV/ENV - 1/

65 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport 100 Estimated suspended sediment load Mt/y SG1 SG2 Ok Om SG3 SG3 SG4 SG5 Background long term estimate Mine-Derived predicted Measured TSS and flow Figure 2-42 Measured and predicted suspended sediment for 2009 at selected stations. Figures 2-43 shows the estimated breakdown of the total suspended sediment load at SG3 since Figure 2-44 shows the same dataset presented in terms of the percentage contribution of tailings, waste rock and natural suspended sediment to the overall suspended sediment load. The 2009 data suggested that the tailings and waste rock comprised a relatively small proportion of the suspended sediment load at SG3 in comparison to previous years. This was due to the continued above-average flows and expected high rates of natural sediment input. PJV/ENV - 1/

66 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Suspended Sediment Load Million Tonnes Period of reliable dump survey Estimated Export of Tailings from Anawe Dump Estimated Suspended Load from Waste Rock Estimated Natural Suspended Sediment Load Figure 2-43 Estimated suspended sediment budget at SG3 since % Percentage of Total Suspended Sediment Load 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Estimated Suspended Load from Tailings Estimated Suspended Load from Waste Rock Estimated Natural Suspended Sediment Load NB: Erodible dump discharge estimated by multiplying annual truck dump figure by long term loss rate approximately 0.55 from dump survey, then multiplied by estimated fines fraction A weighting was also applied to the computed dump export figures to account for above average or below average rainfall. Figure 2-44 Estimated suspended sediment budget at SG3 presented as percentages PJV/ENV - 1/

67 2009 PJV Annual Environmental Report - Hydrology and Sediment Transport Bed Material Load The preceding discussion presents an annual budget for suspended sediment only fine sands, silts and clays. Bed material load coarse sands and gravels that are transported along the bed of the river comprises the remaining 41% of the material eroded from the dumps every year. It is difficult to verify the bed material load budget from field measurements as sampling is extremely difficult and can be hazardous. Estimates are complicated by the fact that some of the bed material load becomes washload during high flow events because higher flows can transport larger particles. Furthermore, abrasion of larger particles occurs during sediment transport along the river meaning that some of the gravels and boulders eroded from the dump are broken down into finer fractions by physical impacts with other particles. Generic rules of thumb derived from the literature suggest that about 10-15% of a river s total load may be comprised of bed material load. Based on this, the bed material input to the river from the erodible dumps would have been approximately 5.0 Mt per year 12.0.Mt x References CSIRO Review of Riverine Impacts. Prepared for PJV by CSIRO, December Davies, M., Parker, G., and Savigny, W Porgera Mine Erodible Dumps Review Panel Final Report, consultant report to the PJV. Davies, M., Mules, G., Markham, A., and Blong R Porgera Joint Venture Porgera Mine Erodible Dumps, Technical Review of Performance Relative to Planned Stage 6 Expansion, review panel report to the PJV. Klohn Crippen Erodible Dump Performance Model, Phase III: February 1999 Calibration, draft consultant report to the PJV. McAlpine, J.F. and Keig, G. with Falls, R. 1983, Climate of Papua New Guinea. CSIRO in association with ANU Press, Canberra. Swanson, K.M., Watson., E., Aalto, R., Wesley Lauer, J., Bera, M.T., Marshall, A., Taylor, M.P., Apte, S.C., and Dietrich, W Sediment Load and Floodplain Deposition Rates: Comparison of the Fly and Strickland Rivers, Papua New Guinea, Journal of Geophysical Research,. 113, F01S03. Parker, G. 1993, Site visit, June, Consultant s report to the PJV, June 9, PJV/ENV - 1/

68 2009 PJV Annual Environmental Report Tailings Monitoring 3.0 TAILINGS MONITORING SUMMARY The average quantity of tailings discharged from the Process Plant during 2009 was 14,879 tonnes per day compared to the 2008 and 2007 average rates of 16,526 and 13,686 tonnes per day, respectively. As in previous years, monitoring of the tailings discharge was conducted on a daily basis during 2009 to independently check the automatic control systems and determine whether the tailings neutralisation circuit was performing as designed. A summary of the results obtained for tailings monitoring is presented below: Tailings monitoring results for 2009 indicated that the neutralisation circuit operated efficiently during the year in detoxifying residual cyanide in the Process Plant tailings discharge. Dissolved concentrations for the various trace metals varied throughout The values for arsenic, copper and iron decreased while mercury increased. The noticeable decrease in copper is mostly likely due to a positive outcome of commissioning the Cyanide Destruction Plant CDP earlier in the year. All other dissolved metal values including cadmium, chromium, lead, nickel, silver and zinc showed no distinct trends. Over the 5-year period from , the dissolved concentrations of most metals decreased including arsenic, chromium, copper, iron, lead and nickel. Cadmium, mercury, silver and zinc showed no distinct trends over the same period. Total metal concentrations throughout 2009 showed no distinct trends with the exception of cadmium which decreased. Over the 5-year period from , there was no distinct trend for any metal. The concentrations of the various forms of cyanide in tailings, i.e. total, weak acid dissociable WAD, cyanide amenable to chlorination CAC and thiocyanate remained within acceptable limits during The most notable variations occurred in 2009 for total, WAD and CAC cyanide, and thiocyanate when the concentrations decreased significantly due to the Cyanide Destruction Plant being commissioned in early Tailings ph mean values remained for most of the time within the control limits 6.4 to 6.6 throughout PJV/ENV 1/10 3-1

69 2009 PJV Annual Environmental Report Tailings Monitoring 3.1 Introduction The riverine disposal of Porgera mine tailings contributes both metal-bearing sediment and dissolved metals to the river system. Tailings are discharged onto the Anawe erodible dump where a portion of the tailings previously trapped in the dump is also released into the river system each year as the dump erodes. The geochemistry of the tailings, the concentration of dissolved metals in the tailings liquor, and dilution rates along the river system have a great influence on the levels of dissolved metals in the water column, notably at the SG3 compliance point at the end of the mixing zone, and in metal levels in fish and prawns along the river system. These dissolved metal levels are tempered to a large extent by adsorption onto natural riverine suspended sediments and to a lesser extent by complexation with dissolved organic matter within the turbid river system. The treatment of tailings in the Process Plant, and in particular lime dosing to ensure that the ph is above 6.5, ensures that dissolved metal levels in the discharge are acceptable. This enables compliance to be achieved at SG3 and that metal levels in fish and prawns, which are present in the river system downstream of SG2, remain acceptable and within international food standard limits. The mean daily Process Plant treated tailings output in 2009 was 14,879 tonnes compared to 16,526 and 13,686 tonnes in 2008 and 2007, respectively. Tailings monitoring was conducted during 2009 on discharge pipe samples to determine whether the tailings neutralization circuit was operating as efficiently as designed by effectively detoxifying the Process Plant tailings before discharge. 3.2 Methods During 2009, the tailings neutralisation circuit was monitored for performance on a continuous basis. Online monitoring of ph was recorded in the Process Plant control room, with low level set points programmed to sound an alarm if the ph dropped below 6.3 for the initial alarm. Procedures are in place for senior Environmental and Process Plant personnel to be notified if the alarm is raised. Under normal operations, should the ph fall further below 6.0, the tailings neutralisation circuit is temporarily shut down and tailings discharge ceases until the problem is rectified. The problem, if it occurs, is normally short-term and involves either difficulties with lime addition for ph control, or temporary plant shutdown for maintenance. During 2009, hourly grab samples of tailings were collected and measured for ph and free cyanide by the Process Plant operators. PJV environmental staff collected two snap samples of tailings each day, morning and afternoon. Each sample was analysed inhouse for ph, total cyanide, weak acid dissociable cyanide WADCN, cyanide amenable to chlorination CAC, thiocyanate, total suspended solids, conductivity, sulphate and temperature. The two daily sample results were averaged for reporting purposes. The daily samples were made into a weekly composite that was analysed for dissolved defined as <0.45 µm filter size and total trace metals. Daily composites were prepared and analysed for sulphate as well as total and weak acid dissociable cyanide from the two snap samples. Each composite sample for dissolved metal analysis was preserved by acidifying with nitric acid and then analysed at the National Measurement Institute laboratory in Sydney formerly Australian Government Analytical Laboratory, AGAL. PJV/ENV 1/10 3-2

70 2009 PJV Annual Environmental Report Tailings Monitoring The results for dissolved and total trace metals as well as cyanide, ph and total suspended solids for 2009 are presented in Tables 3-1A to 3-13A. Summary statistical results for the metals and the other parameters mostly from 2000 to 2009 are presented in Tables 3-1B to 3-13B. 3.3 Results and Discussion Dissolved concentrations for the various trace metals varied throughout Details are provided in the sub-sections of Tailings Monitoring that follow. In summary, the 2009 values for arsenic, copper and iron decreased while mercury increased. All other dissolved metal values including cadmium, chromium, lead, nickel, silver and zinc showed no distinct trends. Over the 5-year period from , the dissolved concentrations of most metals decreased including arsenic, chromium, copper, iron, lead and nickel. Cadmium, mercury, silver and zinc showed no distinct trends over the same period. Total metal concentrations throughout 2009 showed no distinct trends with the exception of cadmium which decreased. Over the 5-year period from , there was no distinct trend for any metal. The concentrations of the various forms of cyanide in tailings, i.e. Total, WAD, CAC and Thiocyanate remained within acceptable limits during The most notable variations occurred in 2009 for total, WAD and CAC cyanide, and thiocyanate when the concentrations decreased noticeably due to the Cyanide Destruction Plant being commissioned in early The ongoing purpose of this plant is to reduce WAD cyanide in the tailings discharged to the environment to less than 0.5mg/L in accordance with the International Cyanide Management Code. Tailings ph mean values remained for most of the time within the control limits 6.4 to 6.6 throughout PJV/ENV 1/10 3-3

71 2009 PJV Annual Environmental Report Tailings Monitoring Arsenic Figure 3-1A shows the trends for dissolved and total arsenic for There is a no distinct trend for either dissolved or total arsenic during the year. The elevated total results for July were checked and found to be correct and are believed to be caused by a surge of arsenic minerals from the mine during that month. The 2009 mean monthly concentrations for arsenic are shown in Table 3-1A. " # % &' % % ' Figure 3-1A Boxplots of dissolved and total arsenic in tailings for #% &' ' % % " % " Figure 3-1B Boxplots of dissolved and total arsenic in tailings from PJV/ENV 1/10 3-4

72 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-1A Mean monthly concentrations mg/l for dissolved and total arsenic for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec As-D As-T Figure 3-1B presents the trends for dissolved and total arsenic in tailings from 2005 to Dissolved arsenic concentrations for 2005 were considerably higher that the much lower results obtained in recent years. Total concentrations were reasonably steady over the same period. Table 3-1B gives a statistical summary of arsenic annual concentrations in tailings for both dissolved and total fractions from Table 3-1B Summary statistics for dissolved and total arsenic concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved arsenic 2000 As-D < As-D As-D As-D As-D As-D As-D As-D As-D As-D Total arsenic 2000 As-T As-T As-T As-T As-T As-T As-T As-T As-T As-D Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved arsenic, T=Total arsenic, N=Number of analyses per year, Stdev=Standard Deviation. PJV/ENV 1/10 3-5

73 2009 PJV Annual Environmental Report Tailings Monitoring Cadmium Figure 3-2A shows the trends for dissolved and total cadmium in tailings for The dissolved and total values for cadmium showed no distinct trends throughout the year. The 2009 mean monthly concentrations for cadmium are shown in Table 3-2A. " # % &' &'& % % '& Figure 3-2A Boxplots of dissolved and total cadmium in tailings for &'#% %" &'& " '& % % # " % " Figure 3-2B Boxplots of dissolved & total cadmium in tailings from PJV/ENV 1/10 3-6

74 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-2A Mean monthly concentrations mg/l for dissolved and total cadmium for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Cd-D Cd-T In Figure 3-2B, dissolved and total cadmium in tailings for the period 2005 to 2009 are shown. There is no definite trend over the 5-year period in either case. Table 3-2B gives a statistical summary of cadmium annual concentrations in tailings for both dissolved and total fractions from Mean dissolved cadmium concentrations rose noticeably from 2000 to 2003 due to a ph trial but have since reduced to lower levels. Table 3-2B Summary statistics for dissolved and total cadmium concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved cadmium 2000 Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Total cadmium 2000 Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved cadmium, T=Total cadmium, N=Number of analyses per year, Stdev=Standard Deviation. PJV/ENV 1/10 3-7

75 2009 PJV Annual Environmental Report Tailings Monitoring Chromium Figure 3-3A shows the trends during 2009 for both dissolved and total chromium. All values for dissolved chromium were at or near the detection limit throughout the year with the exception of October. This elevated value has been checked as correct and the reason for this rise is unknown since the total value for October is not unusually high. Total concentrations showed no definite trend for the same period. The 2009 mean monthly concentrations for chromium are shown in Table 3-3A. " % % %" % % & &' " # % ' 3-3A Boxplots of dissolved and total chromium in tailings for &#% # # &' ' % % % % " Figure 3-3B Boxplots of dissolved & total chromium in tailings from PJV/ENV 1/10 3-8

76 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-3A Mean monthly concentrations mg/l for dissolved and total chromium for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Cr-D Cr-T Figure 3-3B shows boxplots of dissolved and total chromium in tailings from 2005 to Dissolved chromium concentrations were noticeably higher during before decreasing to lower levels in recent years. Total concentrations showed little variation over the 5-year period. Table 3-3B gives a statistical summary of chromium annual concentrations in tailings for both dissolved and total fractions from Table3-3B Summary statistics for dissolved and total chromium concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved chromium 2000 Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Total chromium 2000 Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved chromium, Total chromium, N=Number of analyses per year, Stdev=Standard Deviation 9PJV/ENV 1/10 3-9

77 2009 PJV Annual Environmental Report Tailings Monitoring Copper Figure 3-4A shows the trends during 2009 for both dissolved and total copper. Dissolved copper concentrations showed a downward step-change after January, mostly likely due to a positive outcome of commissioning of the Cyanide Destruction Plant CDP earlier in the year. Total concentrations showed no definite trend for the same period. The 2009 mean monthly concentrations for copper are shown in Table 3-4A. & &' ' % % % % Figure 3-4A Boxplots of dissolved and total copper in tailings for &#% %" &' % ' % % % " " " Figure 3-4B Boxplots of dissolved and total copper in tailings from PJV/ENV 1/

78 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-4A Mean monthly concentrations mg/l for dissolved and total copper for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Cu-D Cu-T Figure 3-4B shows boxplots of dissolved and total copper in tailings from 2005 to Dissolved copper concentrations showed a noticeable decrease in 2009, probably from the CDP, while total concentrations showed little variation over the 5-year period. Table 3-4B gives a statistical summary of copper annual concentrations in tailings for both dissolved and total fractions from The mean dissolved copper concentration decreased sharply in 2009 following the commissioning of the Cyanide Destruction Plant. Table 3-4B Summary statistics for dissolved and total copper concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved copper 2000 Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Total copper 2000 Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved copper, T=Total copper, N=Number of analyses per year, Stedv=Standard deviation. PJV/ENV 1/

79 2009 PJV Annual Environmental Report Tailings Monitoring Iron Figure 3-5A shows the trends during 2009 for both dissolved and total iron. Dissolved iron concentrations showed a noticeable downward trend throughout the year, while total concentrations showed no distinct trend. The 2009 mean monthly concentrations for iron are shown in Table 3-5A. " &' % ' # % " Figure 3-5A Boxplots of dissolved and total iron in tailings for #% &' % ' " # % " " Figure 3-5B Boxplots of dissolved and total iron in tailings from PJV/ENV 1/

80 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-5A Mean monthly concentrations mg/l for dissolved and total iron for 2009 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Fe-D Fe-T Figure 3-5B shows boxplots of dissolved and total iron in tailings from 2005 to Dissolved iron concentrations showed consistently low results for the 5-year period. Total concentrations showed no distinct trend over the same period. Table 3-5B gives a statistical summary of iron annual concentrations in tailings for both dissolved and total fractions from 2000 to Table 3-5B Summary statistics for dissolved and total iron concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved iron 2000 Fe-D Fe-D Fe-D Fe-D Fe-D Fe-D Fe-D Fe-D Fe-D Fe-D Total iron 2000 Fe-T Fe-T Fe-T Fe-T Fe-T Fe-T Fe-T Fe-T Fe-T Fe-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved iron, T=Total iron, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

81 2009 PJV Annual Environmental Report Tailings Monitoring Lead Figure 3-6A shows the trends during 2009 for both dissolved and total lead. Dissolved lead concentrations were at or near the detection level throughout the year. Total lead concentrations varied throughout the year with no distinct trend. The 2009 mean monthly concentrations for lead are shown in Table 3-6A. " # % ' &'& % %" % % " '& Figure 3-6A Boxplots of dissolved and total lead in tailings for '#% % &'& # '& % # % " % " Figure 3-6B Boxplots of dissolved and total lead in tailings from PJV/ENV 1/

82 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-6A Mean monthly concentrations mg/l for dissolved and total lead for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Pb-D Pb-T Figure 3-6B shows boxplots of dissolved and total lead in tailings from 2005 to Dissolved lead concentrations showed a downward trend for the 5-year period. Total concentrations showed no distinct trend over the same period. Table 3-6B gives a statistical summary of lead annual concentrations in tailings for both dissolved and total lead over the 10-year period. Table 3-6B Summary statistics for dissolved and total lead concentration in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved lead 2000 Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Total lead 2000 Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved lead, T=Total lead, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

83 2009 PJV Annual Environmental Report Tailings Monitoring Mercury Figure 3-7A shows the trends during 2009 for both dissolved and total mercury. Dissolved mercury concentrations showed a noticeable increase in December but remained very low. Total mercury concentrations varied throughout the year with no distinct trend. The 2009 mean monthly concentrations for mercury are shown in Table 3-1A. % * &' ' # " % % Figure 3-7A Boxplots of dissolved and total mercury in tailings for *#% # &' # ' % # % % % " Figure 3-7B Boxplots of dissolved and total mercury in tailings from PJV/ENV 1/

84 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-7A Mean monthly concentrations mg/l for dissolved and total mercury for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Hg-D Hg-T Figure 3-7B shows boxplots of dissolved and total mercury in tailings from 2005 to Both dissolved and total mercury concentrations have remained consistent over the 5- year period. Table 3-7B gives a statistical summary of mercury annual concentrations in tailings for both dissolved and total fractions from 2000 to Table 3-7B Summary statistics for dissolved and total mercury concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved mercury 2000 Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Total mercury 2000 Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved mercury, T=Total mercury, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

85 2009 PJV Annual Environmental Report Tailings Monitoring Nickel Figure 3-8A shows the trends during 2009 for both dissolved and total nickel. Both dissolved and total nickel concentrations varied throughout the year and remained low with no noticeable trend. The 2009 mean monthly concentrations for nickel are shown in Table 3-8A. + % &' ' % " " # % Figure 3-8A Boxplots of dissolved and total nickel in tailings for #% " &' ' # " % # % " Figure 3-8B Boxplots of dissolved and total nickel in tailings from PJV/ENV 1/

86 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-8A Mean monthly concentrations mg/l for dissolved and total nickel for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Ni-D Ni-T Figure 3-8B shows boxplots of dissolved and total nickel in tailings from 2005 to Dissolved nickel concentrations showed a slight decrease over the 5-year period while total nickel showed no distinct trend. Table 3-8B gives a statistical summary of nickel annual concentrations in tailings for both dissolved and total fractions from 2000 to Table 3-8B Summary statistics for dissolved and total nickel concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved nickel 2000 Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Total nickel 2000 Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved nickel, T=Total nickel, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

87 2009 PJV Annual Environmental Report Tailings Monitoring Silver Figure 3-9A shows the trends during 2009 for both dissolved and total silver. Dissolved silver concentrations were at or below the detection level throughout the year. Total silver concentrations varied throughout the year with no distinct trend. The 2009 mean monthly concentrations for silver are shown in Table 3-9A. % % &' % % %" % % " ' Figure 3-9A Boxplots of dissolved and total silver in tailings for #% &' % ' % " # % " " Figure 3-9B Boxplots of dissolved and total silver in tailings from PJV/ENV 1/

88 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-9A Mean monthly concentrations mg/l for dissolved and total silver for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Ag-D Ag-T Figure 3-9B shows trend analyses for dissolved and total silver in tailings from 2005 to Dissolved silver concentrations rose in 2005 but have decreased to very low levels in recent years. Total concentrations showed no distinct trend over the 5-year period. Table 3-9B gives a statistical summary of silver annual concentrations in tailings for both dissolved and total fractions from 2000 to Table 3-9B Summary statistics for dissolved and total silver concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved silver 2000 Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Total silver 2000 Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved silver, T=Total silver, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

89 2009 PJV Annual Environmental Report Tailings Monitoring Zinc Figure 3-10A shows the trends during 2009 for both dissolved and total zinc. Both dissolved and total zinc concentrations varied throughout the year with no distinct trends. The 2009 mean monthly concentrations for zinc are shown in Table 3-10A., &'* # # '* % % % % Figure 3-10A Boxplots of dissolved and total zinc in tailings for 2009.,#% &'* '* " # % " # % " Figure 3-10B Boxplots of dissolved and total zinc in tailings from PJV/ENV 1/

90 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-10A Mean monthly concentrations mg/l for dissolved and total zinc for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Zn-D Zn-T Figure 3-10B shows boxplots of dissolved and total zinc in tailings from 2005 to Both dissolved and total zinc concentrations showed no distinct trend over the 5-year period. Table 3-10B gives a statistical summary of zinc annual concentrations in tailings for both dissolved and total fractions from 2000 to Mean dissolved zinc concentrations rose significantly from 2000 to 2003 due to a ph trial but have since reduced to much lower levels. Table 3-10B Summary statistics for dissolved and total zinc concentrations in tailings since 2000 results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved zinc 2000 Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Total zinc 2000 Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved zinc, T=Total zinc, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

91 2009 PJV Annual Environmental Report Tailings Monitoring 3.4 Cyanide Concentrations in Tailings Cyanide detoxification takes place in the tailings neutralisation circuit. Free cyanide in the circuit forms insoluble metal complexes with iron, copper, nickel, lead, zinc, cadmium and silver. The cyanide complexation process with metal species in solution maximizes the reduction of free cyanide levels before discharge. As a check on Process Plant operations during 2009, two daily snap samples were collected morning and afternoon from the tailings discharge by PJV Environment personnel and analysed for total cyanide TCN, weak acid dissociable cyanide WADCN, cyanide amendable to chlorination CAC, and thiocyanate concentrations SCN. TCN and WADCN analyses were conducted on unfiltered samples, while CAC and SCN required the analyses to be conducted on filtered samples. Figure 3-11A shows the concentrations for the various forms of cyanide in tailings, i.e. total, WAD, CAC and thiocyanate for The most notable variations occurred earlier in the year for total and WAD cyanide when the concentrations decreased due to the Cyanide Destruction Plant CDP being commissioned in early The CDP uses the INCO process whereby sulphur dioxide SO 2 is introduced in gas/ liquid form or as sodium metabisulphite at Porgera to oxidize cyanide and thiocyanate into cyanate, which together with metal cyanide complexes are broken down resulting in precipitation of both metal hydroxides and retro cyanide solid precipitates. The reaction is catalysed by the addition of copper as copper sulphate plus POX acid at Porgera with air addition or oxygen at Porgera, and caustic soda to control ph in the range The process takes place in a stirred tank reactor and is straightforward to operate and monitor its performance. % # % # #*' '&,'& " " " # % ++'& ++-'+&'''.',-','&'& Figure 3-11A Monthly concentrations for the various cyanide forms during PJV/ENV 1/

92 2009 PJV Annual Environmental Report Tailings Monitoring Table 3-11A shows the mean monthly results for the various forms of cyanide for Again, the most notable variations occurred earlier in the year with the commissioning of the Cyanide Destruction Plant. Table 3-11A Mean monthly concentrations for the various cyanide forms during Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec TCN WCN CAC SCN TCN= total cyanide, WCN= weak acid dissociable cyanide, CAC= cyanide amenable to chlorination, SCN= thiocyanate Figure 3-11B shows the concentrations for the various forms of cyanide in tailings, i.e. total, WAD, CAC and thiocyanate from 2005 to The concentrations of total, WAD and CAC cyanide showed a sharp decrease in 2009 after the Cyanide Destruction Plant was commissioned earlier in the year. &*'#% % '& " ++'& # " # %,'& % " " Figure 3-11B Mean annual concentrations for various cyanide forms from Table 3-11B Summary statistics for cyanide concentrations from mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Total cyanide 2000 TCN TCN TCN TCN TCN TCN TCN TCN TCN TCN PJV/ENV 1/

93 2009 PJV Annual Environmental Report Tailings Monitoring Year Parameter N Mean Median Stdev Min Max Q1 Q3 Weak acid dissociable cyanide 2000 WADCN WADCN WADCN WADCN WADCN WADCN WADCN WADCN WADCN WADCN Cyanide amenable to chlorination 2000 CAC < CAC < CAC < CAC < CAC < CAC < CAC < CAC < CAC < CAC < Thiocyanate 2000 SCN SCN SCN SCN SCN SCN SCN SCN SCN SCN Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value TCN=Total cyanide, WADCN=Weak Acid Dissociable cyanide, FCN=Free cyanide, SCN=Thiocyanate, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

94 2009 PJV Annual Environmental Report Tailings Monitoring 3.5 ph of Tailings During 2009, regular measurements of tailings ph were conducted on snap samples collected twice daily in the Process Plant, morning and afternoon, by PJV environmental personnel. These results were compared with the digital ph recorder located in the vicinity where the samples were taken. The digital recorder values are the official ph values while those measured on the composite samples in the laboratory are for verification purposes. In previous years, a discrepancy or bias in ph readings was observed between ph values at the tailings discharge point and the results obtained in the environmental laboratory. By the time the tailings samples were taken, then delivered to the laboratory and analysed, the ph of the samples would always be higher than the actual tailings discharge ph from the digital recorder due to continuing chemical reactions within the sample. This situation was corrected in 2001 by simply taking the recorded Process Plant values as the official results rather than those from the environmental laboratory. From Table 3-12A, ph monthly results remained reasonably consistent throughout 2009 and were for most of the time within the operating limits of ph variation Figure 3-12A Monthly ph values for ''0' '&''/ "'0'0' From Table 3-12A, the mean monthly values for ph were mainly between and remained within the ph operating criteria of 6.4 to 6.6. Table 3-12A Mean monthly ph values for Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec ph PJV/ENV 1/

95 2009 PJV Annual Environmental Report Tailings Monitoring From Figure 3-12B, most of the ph values were between 6.5 to 6.6, and the majority of the outliers were above ph 6.6, i.e. towards the conservative alkaline side. #% ''0' '&''/ "'0'0' " Figure 3-12B Monthly ph values from 2005 to In Table 3-12B, ph values over a 10-year period are shown. The years of the ph trial from mid-2000 to late-2003 are clearly seen when the ph was lowered to 6.0. Table 3-12B Summary statistics for ph in tailings from 2000 to Year Parameter N Mean Median Stdev Min Max Q1 Q ph ph ph ph ph ph ph ph ph ph Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value ph=ph units of measurement, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

96 2009 PJV Annual Environmental Report Tailings Monitoring 3.6 Total Suspended Solids TSS in Tailings During 2009, snap samples were collected within the Process Plant at regular times, morning and afternoon, by PJV Environment personnel to monitor for TSS in the tailings discharge. From Figure 3-13A, the median monthly TSS values for 2009 varied between 14-19%. # - % % Figure 3-13A Monthly TSS levels in tailings for 2009 %. From Table 3-13A, the mean monthly results for 2009 remained relatively consistent throughout the year, varying between 15-18%. Table 3-13A Mean monthly TSS levels in tailings for 2009 % Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec % TSS PJV/ENV 1/

97 2009 PJV Annual Environmental Report Tailings Monitoring From Figure 3-13B, the median yearly values for TSS in tailings from 2005 to 2009 showed little variation over the 5-year period. '''#% # # - % % " Figure 3-13B Monthly TSS levels in tailings from 2005 to 2009 %. From Table 3-13B, the mean TSS results have shown a distinct downward trend, decreasing steadily from 23% in 2000 to 17% in Table 3-13B Summary statistics for TSS values in tailings from 2000 to 2009 %. Year Parameter N Mean Median Stdev Min Max Q1 Q TSS TSS TSS TSS TSS TSS TSS TSS TSS TSS Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

98 2009 PJV Annual Environmental Report Compliance Monitoring 4.0 COMPLIANCE MONITORING SUMMARY As in previous years, compliance monitoring was conducted during 2009 on the Upper Strickland River at Tumbudu, where the stream gauging station SG3 is located, to determine whether water quality compliance criteria set by the PNG Government were being met. Each month, a total of 16 samples was taken, i.e. one sample every 6 hours over a 4-day period and analysed for trace metals and other water quality parameters. A summary of the results obtained for compliance monitoring is presented below: All compliance criteria during 2009, as determined by the mean concentrations of the water samples analysed each month for various trace metals and other water quality parameters, were met in accordance with PNG Government requirements. Concentrations of all dissolved metals at SG3 remained relatively steady throughout 2009 with all values well below their respective compliance criteria. Over the 5-year period from , only dissolved arsenic and chromium concentrations decreased with all other metals showing no distinct trends. Concentrations of total metals decreased for mercury and silver during 2009 with all other metals showing no distinct trends. Over the 5-year period from , zinc increased slightly while all other metals were relatively steady. Sulphate concentrations showed no distinct trend during 2009 while the 5-year period from 2005 to 2009 showed a slight increase. Concentrations for dissolved ammonia remained steady at the detection limits for 2009 and from 2005 to The detection limit for ammonia dropped from 25µg/L to 5µg/L during 2009 due to analyses now being conducted at the NMI Laboratory in Sydney rather than the PJV Environmental Chemistry Laboratory. Statistical summary tables for trace metal concentrations at SG3 from 2000 to 2009 showed that the dissolved and total concentrations of mercury and silver decreased over the 10-year period while dissolved arsenic and zinc not total arsenic and zinc showed a similar decline. The dissolved and total concentrations of all other metals remained reasonably steady over the 10-year period. PJV/ENV - 1/10 4-1

99 2009 PJV Annual Environmental Report Compliance Monitoring 4.1 Introduction Compliance monitoring station SG3 marks the end of the mixing zone for PJV. It also marks the end of the tailings and erodible rock compensation zone for people living along the river. It is important for PJV to verify compliance with permit conditions, and to anticipate and mitigate the risk of future non-compliance. This section summarizes the 2009 results for compliance monitoring at SG3 on the Upper Strickland River at Tumbudu. Boxplots of trace metals and other water quality parameters are compared to compliance criteria set by the PNG Government. 4.2 Methods During 2009, water sampling at SG3 each month involved the collection of 16 samples total, i.e. one sample every 6 hours over a 4-day period. Samples were preserved in the field except samples for total metals and ammonia/sulphate and taken to PJV s Environmental Chemistry Laboratory at Porgera for analysis of total suspended solids TSS, cyanide, ammonia, sulphate and sulphide. Samples for total metals did not require preservation, while those for ammonia/sulphate were analysed soon after arriving at the laboratory. Temperature, ph and conductivity were measured in the field immediately after each sample was taken. Samples for dissolved metals were filtered in the PJV Environment Lab using a 0.45µm acid-washed polycarbonate filter and holder 250mL, and preserved with ultra-pure grade nitric acid before shipment to a contract laboratory in Australia. Samples for total metals were neither filtered nor preserved before shipment. The contracted laboratory is the National Measurement Institute laboratory formerly AGAL in Sydney. Results of monthly compliance monitoring that were reported to the PNG Department of Environment and Conservation DEC on a quarterly basis included ph, cyanide and ammonia, as well as dissolved arsenic, cadmium, chromium, copper, lead, nickel, silver and zinc. Additional non-compliance parameters reported to the DEC included total suspended solids, river flow, total mercury and sulphide. There is no compliance value for dissolved mercury at SG3 because the mean values have always been at or below the detection limit since operations began. The PNG Government has requested that PJV measure total mercury at SG3 as an indicator of the mercury loading in the river system from natural sources and the Porgera mine. 4.3 Trace Metals and Other Parameters The 2009 data for dissolved and total metal concentrations and other parameters for SG3 are presented as trend analyses in Figures 4-1A to 4-13A. Also presented are 5- year trend graphs from Figures 4-1B to 4-13B. The analyses were performed on individual sample results using MINITAB software to show boxplots for each trace metal and other parameters. An explanation on how to interpret boxplots is presented in Appendix 1. The results of previous years that summarise the statistics for each variable are presented as comparison tables in Tables 4-1 to PJV/ENV - 1/10 4-2

100 2009 PJV Annual Environmental Report Compliance Monitoring Arsenic Monthly dissolved arsenic concentrations remained consistently low during Despite dissolved arsenic results rising noticeably in April, May and October, all results were well below the compliance criterion of 50µg/L Figure 4-1A. Concentrations of total arsenic remained relatively consistent throughout the year. " " "" "%&' #" Figure 4-1A Boxplots of dissolved and total arsenic at SG3 for % " #" # + + * " + * Figure 4-1B Boxplots of dissolved and total arsenic at SG3 from PJV/ENV - 1/10 4-3

101 2009 PJV Annual Environmental Report Compliance Monitoring The 5-year trends for both dissolved and total arsenic from are shown in Figure 4-1B. A slight downward trend over 5 years is noted for dissolved arsenic while no obvious trend is seen for total arsenic. Annual mean dissolved and total arsenic concentrations from 2000 to 2009 are shown in Table 4-1. Dissolved mean arsenic concentrations have remained consistently low since Total mean arsenic concentrations have shown no obvious trend over the past 10 years. Table 4-1 Summary statistics for dissolved and total arsenic concentrations from 2000 to 2009 at SG3 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved arsenic 2000 As-D < As-D As-D As-D As-D As-D As-D As-D As-D As-D Total arsenic 2000 As-T As-T As-T As-T As-T As-T As-T As-T As-T As-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved arsenic, T=Total arsenic, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/10 4-4

102 2009 PJV Annual Environmental Report Compliance Monitoring Cadmium Monthly dissolved cadmium concentrations remained at the detection level of 0.2µg/L throughout 2009 and well below the compliance criterion of 1.0 µg/l Figure 4-2A. Total cadmium concentrations varied throughout the year without showing a distinct trend. & #,,,,*, " " "", "%&' * + #" Figure 4-2A Boxplots of dissolved and total cadmium at SG3 during &%, " * #" +, #,,*, + * " + * Figure 4-2B Boxplots of dissolved and total cadmium at SG3 from PJV/ENV - 1/10 4-5

103 2009 PJV Annual Environmental Report Compliance Monitoring Dissolved concentrations for cadmium remained consistently at or below the detection limit of 0.2µg/L from as shown in Figure 4-2B. Total concentrations showed a slight upward trend during the same period. Annual mean dissolved and total cadmium concentrations from 2000 to 2009 are shown in Table 4-2. Mean dissolved concentrations have remained steady since The mean total cadmium concentrations have remained consistently low for the past 10 years. Table 4-2 Summary statistics for dissolved and total cadmium concentrations from 2000 to 2009 at SG3 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved cadmium 2000 Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Cd-D Total cadmium 2000 Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Cd-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved cadmium, T=Total cadmium, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/10 4-6

104 2009 PJV Annual Environmental Report Compliance Monitoring Chromium Monthly dissolved chromium concentrations were either at or below the detection limit of 1µg/L throughout 2009, and well below the compliance criterion of 10µg/L Figure 4-3A. Total chromium concentrations varied throughout 2009 without showing any distinct trend., " #", " "" "%&' #,,*, Figure 4-3A Boxplots of dissolved and total chromium at SG3 during %, " #", #,,*, + * " + * Figure 4-3B Boxplots of dissolved and total chromium at SG3 from Dissolved chromium concentrations were either at or below the detection limit over the 5-year period from as shown in Figure 4-3B. Total chromium concentrations showed consistent results during the same period. PJV/ENV - 1/10 4-7

105 2009 PJV Annual Environmental Report Compliance Monitoring Annual mean dissolved and total chromium concentrations from 2000 to 2009 are shown in Table 4-3. The dissolved concentrations have remained at 1µg/L since The total chromium concentrations have shown relatively consistent results over the past 10 years. Table 4-3 Summary statistics for dissolved and total chromium concentrations from 2000 to 2009 at SG3 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved chromium 2000 Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Cr-D Total chromium 2000 Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Cr-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved chromium, T=Total chromium, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/10 4-8

106 2009 PJV Annual Environmental Report Compliance Monitoring Copper The monthly dissolved copper concentrations during 2009 were low and showed little variation, remaining well below the compliance value of 10µg/L Figure 4-4A. One isolated result during the year 26µg/L was dismissed as a contaminated sample. Total copper concentrations varied noticeably throughout 2009 without causing any concern. '' # " " #" Figure 4-4A Boxplots of dissolved and total copper at SG3 during ''% " #" # + + * " + * Figure 4-4B Boxplots of dissolved and total copper at SG3 from PJV/ENV - 1/10 4-9

107 2009 PJV Annual Environmental Report Compliance Monitoring Both dissolved and total copper concentrations showed little systematic variation at SG3 over the 5-year period from as shown in Figure 4-4B. Annual mean dissolved copper concentrations at SG3 showed little variation from 2000 to 2009, ranging from 1-2µg/L as shown in Table 4-4. The total copper values varied during the same period but within acceptable limits Table 4-4. Table 4-4 Summary statistics for dissolved and total copper concentrations from 2000 to 2009 at SG3 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved copper 2000 Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Cu-D Total copper 2000 Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Cu-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved copper, T=Total copper, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/

108 2009 PJV Annual Environmental Report Compliance Monitoring Iron Both monthly dissolved and total iron concentrations varied noticeably throughout 2009 Figure 4-5A. " #" # + Figure 4-5A Boxplots of dissolved and total iron at SG3 for % * " #" + # + * " + * Figure 4-5B Boxplots of dissolved and total iron at SG3 for PJV/ENV - 1/

109 2009 PJV Annual Environmental Report Compliance Monitoring Both dissolved and total iron concentrations have shown little systematic variation over the 5-year period from as shown in Figure 4-5B. Annual mean dissolved iron concentrations have remained consistently low since 2003 Table 4-5. Mean total iron concentrations have increased over the same period. Table 4-5 Summary statistics for dissolved and total iron concentrations at SG3 from 2003 to 2009 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved iron 2003 Fe-D Fe-D Fe-D Fe-D Fe-D Fe-D Fe-D Total iron 2003 Fe-T Fe-T Fe-T Fe-T Fe-T Fe-T Fe-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved iron, T=Total iron, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/

110 2009 PJV Annual Environmental Report Compliance Monitoring Lead Monthly dissolved lead concentrations were at or below the detection limit of 0.5µg/L throughout 2009, and well below the compliance criterion of 3µg/L as shown in Figure 4-6A. Total lead concentrations varied throughout the year with no distinct trend. &, " #" #,,,*, " "", "%&' Figure 4-6A Boxplots of dissolved and total lead at SG3 during 2009., &% " #", #,,*, + * " + * Figure 4-6B Boxplots of dissolved and total lead at SG3 from PJV/ENV - 1/

111 2009 PJV Annual Environmental Report Compliance Monitoring Dissolved lead concentrations have been at or below the detection limit of 0.5µg/L for the 5-year period from , as shown in Figure 4-6B. Total lead concentrations remained relatively steady during the same period. Annual mean dissolved and total lead concentrations at SG3 from 2000 to 2009 are shown in Table 4-6. The dissolved lead concentrations have remained steady at 0.5µg/L since The total lead concentrations have remained relatively steady for the past ten years. Table 4-6 Summary statistics for dissolved and total lead at SG3 from 2000 to 2009 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved lead 2000 Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Pb-D Total lead 2000 Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Pb-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved lead, T=Total lead, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/

112 2009 PJV Annual Environmental Report Compliance Monitoring Mercury Monthly dissolved mercury concentrations at SG3 were at or below the detection limit of 0.1µg/L during 2009 Figure 4-7. Total mercury concentrations remained low with a slight upward trend occurring towards the latter part of the year. #,,,, *, ",,,*,+,,,,,, #" Figure 4-7A Boxplots of dissolved and total mercury at SG3 during % " #",, #,,,,,+, *,,, + *, " + * Figure 4-7B Boxplots of dissolved and total mercury at SG3 from PJV/ENV - 1/

113 2009 PJV Annual Environmental Report Compliance Monitoring Dissolved mercury concentrations were at or below the detection limit of 0.1µg/L at SG3 during the 5-year period from Figure 4-7B. Total mercury concentrations have remained consistently low during the same period. Annual mean dissolved mercury concentrations have shown little variation from 2000 to 2009 as shown in Table 4-7. Total mercury concentrations have decreased noticeably over the same period. This confirms observations that there is less mercury within the ore body with increasing depth in the open pit. Table 4-7 Summary statistics for dissolved and total mercury concentrations at SG3 from 2000 to 2009 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved mercury 2000 Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Hg-D Total mercury 2000 Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Hg-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved mercury, T=Total mercury, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/

114 2009 PJV Annual Environmental Report Compliance Monitoring Nickel Monthly dissolved nickel concentrations for nickel were at or below the detection limit of 1µg/L during 2009 Figure 4-8A. Concentrations for total nickel varied throughout 2009 without showing any specific trend., "- #"- #,,,*, " "" "%&' Figure 4-8A Boxplots of dissolved and total nickel at SG3 during %, "- #"-, #,,,, + * " + * Figure 4-8B Boxplots of dissolved and total nickel at SG3 from PJV/ENV - 1/

115 2009 PJV Annual Environmental Report Compliance Monitoring With the exception of 2005, dissolved nickel concentrations at SG3 from 2005 to 2009 were at or below the detection limit of 1µg/L Figure 4-8B. Total nickel concentrations remained reasonably steady over the same 5-year period. Mean dissolved nickel concentrations have shown no change at SG3 from 2000 to 2009 Table 4-8. In contrast, total nickel concentrations have varied between 41-99µg/L over the same period. Table 4-8 Summary statistics for dissolved and total nickel at SG3 from 2000 to 2009 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved nickel 2000 Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D Ni-D < Total nickel 2000 Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Ni-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved nickel, T=Total nickel, N=Number of analyses per year, Stdev=Standard deviation PJV/ENV - 1/

116 2009 PJV Annual Environmental Report Compliance Monitoring Silver Monthly dissolved silver concentrations at SG3 were at or below the detection limit of 0.2µg/L throughout 2009 Figure 4-9A. Total silver concentrations showed a slight upward trend during the same period., " #" #,,,*, " "", "%&' Figure 4-9A Boxplots of dissolved and total silver at SG3 during %, " * #", +,,*, + * " + *. Figure 4-9B Boxplots of dissolved and total silver at SG3 from PJV/ENV - 1/

117 2009 PJV Annual Environmental Report Compliance Monitoring Dissolved silver concentrations at SG3 from were at or below the detection limit of 0.2µg/L Figure 4-9B. Total silver concentrations for the same period were relatively consistent. From Table 4-9, annual mean dissolved silver concentrations were at a peak of 0.6µg/L in 2000 before a drop to a steady low level of 0.2µg/L. Mean total silver concentrations followed a similar trend, declining to 1 µg/l over the same period. Table 4-9 Summary statistics for dissolved and total silver at SG3 from 2000 to 2009 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved silver 2000 Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Ag-D Total silver 2000 Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Ag-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved silver, T=Total silver, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV - 1/

118 2009 PJV Annual Environmental Report Compliance Monitoring Zinc Monthly dissolved zinc concentrations varied noticeably throughout 2009 with all results well below the compliance criterion of 50µg/L Figure 4-10A. One isolated result during the year 60µg/L was dismissed as a contaminated sample. Total zinc concentrations varied throughout the year with no distinct trend. # * + ". " + + #". Figure 4-10A Boxplots of dissolved and total zinc at SG3 during % ". + #". # + + * " + * Figure 4-10B Boxplots of dissolved and total zinc at SG3 from PJV/ENV - 1/

119 2009 PJV Annual Environmental Report Compliance Monitoring Dissolved zinc concentrations at SG3 showed no distinct trend from 2005 to 2009 as shown in Figure 4-10B. Total zinc concentrations showed a very slight upward trend during the same period. Mean dissolved zinc concentrations from 2000 to 2009 showed a distinct downward trend as shown in Table 4-10, while mean total zinc concentrations were varied with no specific trend over the same period. Table 4-10 Summary statistics for dissolved and total zinc concentrations at SG3 from 2000 to 2009 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q3 Dissolved zinc 2000 Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Zn-D Total zinc 2000 Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Zn-T Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved zinc, T=Total zinc, N=Number of analyses per year, Stdev=Standard deviation. Summary of metals data The following tables, Tables 4-11 and Table 4-12, show the SG3 results of all metals compared to the PNG Government compliance criteria for 2009 and from , respectively. No samples were obtained during January 2009 due to Landowner concerns. PJV/ENV - 1/

120 2009 PJV Annual Environmental Report Compliance Monitoring Table 4-11 Summary Table - Mean monthly trace metal concentrations at SG3 for 2009 all units in µg/l Month As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T Pb-D Pb-T Hg-D Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T Jan Feb < <1 122 < < < <1 180 < Mar < <1 81 < < < <1 105 < Apr < < < < <1 70 < May < < < < <1 104 < Jun < < < < <1 76 < Jul < < < < <1 120 < Aug < < < < <1 99 < Sep < < < < <1 51 < Oct < < < < <1 57 < Nov < < < < <1 78 < Dec < < < < <1 148 < Criterion NC 3 NC Note: D = dissolved; T = total; NC = no criterion PJV/ENV - 1/

121 2009 PJV Annual Environmental Report Compliance Monitoring Table 4-12 Summary Table - Mean annual trace metals concentrations at SG3 since 2000 all units in µg/l except ph Year As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T Pb-D Pb-T Hg-D Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T ph-l < < < < <1 49 < < < < <1 67 < < < < < <1 58 < < < < <0.1 <0.1 <1 46 < < < < <0.1 < < < < < <0.1 < < < < < <0.1 <0.1 <1 59 < < < < <0.1 <0.1 <1 66 < < < < < <1 99 < Criterion NC 3 NC Note: D = dissolved; T = total; NC = no criterion; L = laboratory PJV/ENV - 1/

122 2009 PJV Annual Environmental Report Compliance Monitoring General Discussion With the introduction of the cyanide destruction plant, dissolved metal concentrations at the compliance site, SG3, not only now meet the PNG compliance criteria, but are also below the stringent Australian and New Zealand water quality guidelines for ecosystem protection ANZECC/ARMCANZ, 2000 as shown in Table This is based only on the dissolved metal concentrations, and without the allowed consideration of metal bioavailability. The bioavailable metals concentration would be even lower than the dissolved values indicating that at this site and all downstream sites there are likely to be no acute or chronic impacts on aquatic biota. Table 4-13 Comparison of 2009 mean dissolved metals concentrations at SG3 with Australian and New Zealand water quality guideline trigger values Metal Mean Dissolved Metals at SG3 in 2009 PNG Compliance Value ANZECC/ARMCANZ Trigger Value * µg/l Arsenic AsIII Cadmium < Chromium <1 1 1 CrVI Copper Lead < Mercury < Nickel < Silver < Zinc * * Guidelines for Cu, Pb, Cd, Ni and Zn are hardness dependent. These values are for 30 mg/l CaCO 3 hardness 4.4 Other Water Quality Parameters Free Cyanide During 2009, all free cyanide analyses of river samples at SG3 were below the analytical detection limit of 20µg/L and assumedly below the compliance criterion of 5µg/L Ammonia Ammonia levels at SG3 were either at or below the detection limits during 2009 and for the period from 2005 to 2009 as shown in Figures 4-11A & B and in Table Note that the detection limit for ammonia improved from 25µg/L to 5µg/L during This is due to ammonia analyses now being conducted by the NMI Lab in Sydney instead of PJV Environmental Chemistry Lab where the detection limit is considerably lower. PJV/ENV 1/

123 2009 PJV Annual Environmental Report Compliance Monitoring # Figure 4-11A Trend analysis for dissolved ammonia at SG3 during % # + * Figure 4-11B Trend analysis for dissolved ammonia at SG3 from Table 4-14 Summary statistics for dissolved ammonia at SG3 from 2003 to 2009 all results in µg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q NH 3 -D 192 < <25 <25 <25 < NH 3 -D 192 < <25 <25 <25 < NH 3 -D 190 < <25 <25 <25 < NH 3 -D 191 < <25 <25 <25 < NH 3 -D 178 < <25 <25 <25 < NH 3 -D 176 < <25 <25 <25 < NH 3 -D 176 <5 <5 0 <5 <5 <5 <5 Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved NH3, N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

124 2009 PJV Annual Environmental Report Compliance Monitoring Sulphide For 2009, all results for sulphide concentrations at SG3 were at or below the detection limit of 10µg/L. Currently, there is no compliance criterion for sulphide at SG Sulphate The monthly trend for sulphate concentrations at SG3 showed no obvious trend for 2009 Figure 4-12A. There is no compliance criterion for sulphate at SG3. Annual values show a slight upward trend for the 5-year period from in Figure 4-12B. Little variation is seen in the mean annual results from as presented in Table * &&' + Figure 4-12A Trend analysis for sulphate concentrations at SG3 during * ' % + + * " Figure 4-12B Trend analysis for sulphate at SG3 from mg/l. PJV/ENV 1/

125 2009 PJV Annual Environmental Report Compliance Monitoring Table 4-15 Summary statistics for sulphate concentrations at SG3 from 2001 to 2009 all results in mg/l. Year Parameter N Mean Median Stdev Min Max Q1 Q SO 4 -D SO 4 -D SO 4 -D SO 4 -D SO 4 -D SO 4 -D SO 4 -D SO 4 -D SO 4 -D Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value D=Dissolved SO 4, N=Number of analyses per year, Stdev=Standard deviation ph Measurement During 2009, the median monthly values for ph at SG3 varied between 8.0 and 8.3 Figure 4-13A, and well within the compliance criteria of 6.0 to 9.0., ', "/"""+, "0", ',,, Figure 4-13A Trend analysis for ph measurement at SG3 during PJV/ENV 1/

126 2009 PJV Annual Environmental Report Compliance Monitoring, '%, ' *, *, +, + * " Figure 4-13B Trend analysis for median ph values at SG3 from The median ph values for the 5-year period from showed little variation Figure 4-13B. From 2000 to 2009, mean ph values indicated a stable river system with values varying in the limited range from 7.8 to 8.2 Table Table 4-16 Summary statistics for ph measurement at SG3 from 2000 to 2009 all results in ph units. Year Parameter N Mean Median Stdev Min Max Q1 Q ph ph ph ph ph ph ph ph ph ph Q1 Lower Quartile 25% of data below this value; Q3 Upper quartile 75% of the data below this value N=Number of analyses per year, Stdev=Standard deviation. PJV/ENV 1/

127 2009 PJV Annual Environmental Report Compliance Monitoring 4.5 Sewage Treatment and Drinking Water Treatment Sewage Treatment Plant Analyses Results for the five onsite sewage treatment plants for 2009 are shown in Table The main parameters tested in the onsite PJV Environmental Lab were for faecal coliforms, biochemical oxygen demand over 5 days BOD 5 and total suspended solids TSS. QA/QC was conducted on the BOD 5 samples using certified reference material supplied by Graham B Jackson P/L of Australia, and which originated from the Analytical Products Group in the USA. As shown in the table, ongoing maintenance problems with the sewage treatment plants were resolved by June, allowing the faecal coliform results to be within compliance. Further maintenance is required to bring the TSS values within compliance. For the most part, BOD 5 results were within compliance. Table 4-17 Results of Sewage Treatment Plant Analyses for 2009 Sites Parameter Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Alipis 2 Faecal Coliform* nil nil nil nil nil nil nil nil nil nil BOD TSS Yoko Faecal Coliform* No Flow nil nil nil nil nil nil nil nil nil BOD 5 nil TSS Tawasakali Faecal Coliform* nil nil nil nil nil nil nil nil nil BOD TSS Plantsite Faecal Coliform* 500 nil nil nil nil nil nil nil 100 nil BOD TSS Suyan Faecal Coliform* nil nil 150 nil nil nil nil nil BOD TSS * Units in counts/100ml. Units for BOD 5 and TSS in mg/l Notes: Compliance for faecal coliforms = 200 counts/100ml Compliance for BOD 5 = 100 mg/l Compliance for TSS = 30 mg/l Drinking Water Treatment Analyses Results for the three onsite drinking water treatment plants for 2009 are shown in Table The two main parameters tested were for faecal and total coliforms which are a measure of biological contamination. PJV/ENV 1/

128 2009 PJV Annual Environmental Report Compliance Monitoring Table 4-18 Results of Drinking Water Treatment Plant Analyses 2009 Sites Parameter Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Counts/100ml Suyan Faecal Coliforms nil nil nil nil nil nil nil nil nil nil nil nil Total Coliforms nil nil nil nil nil nil nil nil nil nil nil nil Anawe Faecal Coliforms nil nil nil nil nil nil nil nil nil nil nil nil Total Coliforms nil nil nil nil nil nil nil nil nil nil nil nil Tawisakale Faecal Coliforms nil nil nil nil nil nil nil nil nil nil nil nil Total Coliforms nil nil nil nil nil nil nil nil nil nil nil nil Note: Compliance for faecal coliforms = zero counts/100ml Compliance for total coliforms = 3 counts/100ml Permitted Waste Discharge Quantities Annual permitted waste discharge quantities from the mine site include the Process Plant tailings and waste rock discharges from the Anjolek and Anawe erodible dumps. Table 4-19 presents the respective discharge rates for 2009 compared to the permitted quantities. Table 4-19 Discharge quantities from Erodible Dumps and Tailings Mm 3 /a* Discharge Site Discharge Quantity 2009 Permitted Quantity Anjolek Erodible Dump Anawe Erodible Dump Tailings Slurry Ex-pipe * Mm 3 /a = million cubic metres per annum Permitted Abstraction Quantities Permitted abstraction quantities are in place for water drawn from Waile Creek dam, and from Kogai Creek at the toe of the Kogai Stable Dump for makeup water required in the process plant. Abstraction quantities and permitted amounts are shown in Table Table 4-20 Abstraction rates from Waile Creek Dam and Kogai Creek Mm 3 /a* Abstraction Site Abstraction Quantity 2009 Permitted Quantity Waile Creek Dam Kogai Creek at Kogai toe * Mm 3 /a = million cubic metres per annum PJV/ENV 1/

129 2009 PJV Annual Environmental Report Compliance Monitoring 4.7 Laboratory Quality Assurance and Quality Control Report Accurate data are critical to the credibility of the environmental monitoring programs. All samples are collected by trained personnel following best practice sampling protocols and accurate analysis is confirmed through quality assurance principles. The PJV environmental chemistry laboratory is certified to PNGLAS Papua New Guinea Laboratory Accreditation Scheme, Registration Number 0036 and all offsite samples are analyzed by National Measurement Institute laboratory NATA accredited in Sydney. The objective of this section of the report is to verify the reliability of data for QC samples as a means to accept the compliance data at the SG3 monitoring point. The following key characteristics were used in the verification process: Accuracy closeness of the measured value to the true value for the sample. Accuracy is determined using analysis of reference materials Precision random error introduced by using the test method, a general term for the variability between repeated tests Introduction Three QC samples, supplied as natural water concentrates and used in 2009, were sourced from Graham B Jackson P/L in Australia. The samples were originally supplied by Environmental Resource Associates ERA of the USA which took over the Analytical Products Group in The samples were found to be homogenous at 95% confidence level and certified by evaluation through inter-laboratory round-robin programs. Certified reference material CRM No /7 was employed between January and March while CRM No was employed between April and August and CRM No was between September and December of Test data were plotted on quality control charts to accept data for the individual sample batches and check performance of laboratory. The dissolved metals; arsenic, cadmium, chromium, copper, lead, mercury, nickel, silver and zinc were monitored for this purpose. Basic statistical calculations of mean, standard deviation STDEV, percent relative standard deviation %RSD=STDEVx100/mean and per cent recovery analytical mean x100/true mean were done on individual metals and results are presented below in Tables 4-20 A, B and C. PJV/ENV - 1/

130 2009 PJV Annual Environmental Report Compliance Monitoring Data Analysis Accuracy and precision tests were done on QC samples data where accuracy is expressed as percentage of recovery %R and precision as % relative standard deviation %RSD. The accepted recoveries for metals are between %. Statistical data summaries are given in Tables 4-20 A, B and C and respective scatter plots are presented in Figure Analytical mean values for all metals were within the acceptable limits. Percent recoveries and relative standard deviation for all metals fall within acceptable ranges of % and 0-9.6% respectively except for Hg. The recovery for the first and last samples were 73% and 70% respectively while precision was poor for all the three lots. The poor recovery and precision may be due to loss of Hg during transition or any errors associated with the analytical processes. For all metals, 98.4% of the data fall within the acceptance limits while 1.6% of data fall outside of the limits. For the purpose of this report, there was good accuracy and precision for the QC samples employed by the laboratory in 2009 and water quality data for SG3 was accepted. Table 4-21A Statistical data of certified reference material No /7 Certified values Measured values Metals Mean 1 Accepted Limits 2 Mean 3 % RSD 4 % Recov 5 ug/l ug/l ug/l As-D Cd-D Cr-D Cu-D Pb-D Hg-D Ni-D Ag-D Zn-D Mean 1 = Analytical Product Group APG certified mean, Accepted Limits 2 = APG accepted limits, Mean 3 =Analytical mean, %RSD 4 = per cent relative standard deviation, % Recov 5 = per cent recovery PJV/ENV - 1/

131 2009 PJV Annual Environmental Report Compliance Monitoring Table 4-21B Statistical data of certified reference material No Certified values Measured values Metals Mean 1 Accepted Limits 2 Mean 3 % RSD 4 % Recov 5 ug/l ug/l ug/l As-D Cd-D Cr-D Cu-D Pb-D Hg-D Ni-D Ag-D Zn-D Mean 1 = Analytical Product Group APG certified mean, Accepted Limits 2 = APG accepted limits, Mean 3 =Analytical mean, %RSD 4 = per cent relative standard deviation, % Recov 5 = per cent recovery Table 4-21C Statistical data of certified reference material No Certified values Measured values Metals Mean 1 Accepted Limits 2 Mean 3 % RSD 4 % Recov 5 ug/l ug/l ug/l As-D Cd-D Cr-D Cu-D Pb-D Hg-D Ni-D Ag-D Zn-D Mean 1 = Analytical Product Group APG certified mean, Accepted Limits 2 = APG accepted limits, Mean 3 =Analytical mean, %RSD 4 = per cent relative standard deviation, % Recov 5 = per cent recovery PJV/ENV - 1/

132 2009 PJV Annual Environmental Report Compliance Monitoring "# % & ' % % * +,*- *.,&& *.%+,%+. Figure 4-14 Dissolved Arsenic trends of QC samples PJV/ENV - 1/

133 2009 PJV Annual Environmental Report Compliance Monitoring %&% %&% %&% %&% "# % & ' /% %&%* +,* - %&%*.,&& %&%*.%+,%+. Figure 4-14 cont Dissolved Cadmium trends of QC samples PJV/ENV - 1/

134 2009 PJV Annual Environmental Report Compliance Monitoring -%&% -%&% -%&% -%&% "# % & ' % % -%&%* +,*- -%&%*.,&& -%&%*.%+,%+. Figure 4-14 cont Dissolved Chromium trends of QC samples PJV/ENV - 1/

135 2009 PJV Annual Environmental Report Compliance Monitoring "# % & ' % % * +,*- *.,&& *.%+,%+. Figure 4-14 cont Dissolved Copper trends of QC samples PJV/ENV - 1/

136 2009 PJV Annual Environmental Report Compliance Monitoring "# % & ' % % * +,*- *.,&& *.%+,%+.. Figure 4-14 cont Dissolved Lead trends of QC samples PJV/ENV - 1/

137 2009 PJV Annual Environmental Report Compliance Monitoring %&0 *&0 *&0 *&0 "# % & ' % % * &0 * +,*- * &0 *.,&& * &0 *.%+,%+. Figure 4-14 cont Dissolved Mercury trends of QC samples PJV/ENV - 1/

138 2009 PJV Annual Environmental Report Compliance Monitoring "# % & ' % % 1* +,*- 1*.,&& 1*.%+,%+. Figure 4-14 cont Dissolved Nickel trends of QC samples PJV/ENV - 1/

139 2009 PJV Annual Environmental Report Compliance Monitoring "# % & ' % % * +,*- *.,&& *.%+,%+. Figure 4-14 cont Dissolved Silver trends of QC samples PJV/ENV - 1/

140 2009 PJV Annual Environmental Report Compliance Monitoring "# % & ' % % 2* +,*- 2*.,&& 2*.%+,%+. Figure 4-14 cont Dissolved Zinc trends of QC samples PJV/ENV - 1/

141 2009 PJV Annual Environmental Report River Monitoring 5.0 RIVER MONITORING SUMMARY Water quality and bed sediment monitoring of the fate of trace metals from the Porgera operations was conducted during 2009 at a number of downstream locations from the mine site to Lake Murray comprising SG1, SG2, Wankipe, SG3, Bebelubi, SG4, SG5 and SG6 on the Herbert River. It was only possible to obtain one set of samples at SG1 during 2009 due to landowner concerns. Off-river control sites on the Upper Lagaip River, Pori R., Ok Om, Kuru R., Baia R. and Tomu R. were included in the monitoring program. For each monitoring location, water quality samples were analysed for dissolved and total trace metals, and physical parameters, to assess water quality conditions in the Porgera/ Lagaip/Strickland river system downstream of the mine. Bed sediment samples taken at the same locations along the river system were analysed for metals in the minus 63 micron <63µm size fraction and for total metals. This determined whether the trace metals were present in either the finer or coarser fractions. A summary of the results obtained for river monitoring is presented below: The mean dissolved concentrations of arsenic, chromium, copper, lead, nickel, silver and zinc for 2009 were below their SG3 compliance criteria at all downstream monitoring stations. Cadmium was below its SG3 criterion at all sites downstream of SG1. Total values of all trace metals decreased substantially from the SG1 monitoring station to the Lower Strickland River at SG5 due to dilution from natural suspended sediments from tributaries joining the main river. During 2009, the annual mean dissolved concentrations of all relevant trace metals at SG2 i.e. arsenic, cadmium, chromium, copper, lead, nickel, silver and zinc were lower than their respective compliance criteria set for SG3. This occurs even though SG2 is about one quarter the down-river distance to SG3 42km vs 165km. The 2009 mean annual value for copper at SG2 was 1.6µg/L, which is much lower than values obtained in previous years and well below the SG3 compliance criterion of 10µg/L. This change is probably due to the Cyanide Destruction Plant CDP which was commissioned within the process plant in early The CDP was installed to reduce WAD cyanide levels in tailings but it also had the additional effect of reducing some dissolved metals at SG2, especially copper. Dissolved and total metals in the water column for arsenic, cadmium, chromium, copper, lead, mercury, nickel, silver and zinc have generally shown little change downstream of the mine over the 10-year period from 2000 to For downstream bed sediments, trace metal concentrations in the <63µm and total fractions showed considerable variability from the Porgera mine to SG5 in the Lower Strickland region. The values generally have decreased as mine-derived sediments become diluted with the influx of natural sediments from tributaries along the river system. Sometimes this trend is difficult to see because of the relatively low number of samples taken during the year and the existence of background levels of metals in the natural sediments. For 2009, the dissolved and total concentrations for most metals decreased, PJV/ENV 1/10 5-1

142 2009 PJV Annual Environmental Report River Monitoring as expected, with increasing distance downstream of the mine. However, chromium showed no distinct trend for both the finer and total fractions, while nickel showed no distinct trend in the finer fraction only. Concentrations of dissolved metals in local creeks for 2009, in general, were similar to those obtained over the 5-year period from The higher results for some metals at 28 Level, Yakatabari Creek and Yunarilama Portal are due to discharges from the open pit and underground workings. The levels of dissolved zinc and cadmium, in particular, from the stable dumps for 2009 when compared with the 5-year period from show that metal leaching from minor sulphide oxidation within the dumps has remained reasonably steady and is currently not a concern. Metal leaching from the Kogai Stable Dump monitored at Kogai Toe has decreased over the past 10 years, probably due to a topsoil capping being put in place and thereby minimizing sulphide oxidation. In contrast, the Anawe North Stable Dump monitored at Wendako Creek, which has yet to be capped, continues to show signs of sulphide oxidation and subsequent metal leaching cadmium and zinc. This is expected to decrease, similar to the Kogai SD, once the Anawe North is capped. Total metal concentrations recorded for all local sites during 2009 were, in general, similar to those recorded for past five years from The results clearly show the predominance of total metals coming from the open pit and underground areas via 28 Level, Yakatabari Creek and Yunarilama Portal. All total metal values from these areas are relatively low and within acceptable limits. Dissolved metal concentrations in local creeks decrease rapidly downstream due to river dilution and adsorption onto natural sediments; however, total metals i.e. mainly metalbearing total suspended solids decrease by natural sediment dilution from landslides and tributaries of the Strickland River system. Local creek ph values for 2009 were generally consistent with historical monitoring data. The exception was the stream flowing from the lime plant, which was moderately alkaline ph Alkalinity measurements from the lime plant showed a range of results depending on plant operating conditions. Sulphate results showed elevated readings for water released from the SDA toe, Yakatabari Creek and Yunarilama Portal as a result of minor sulphide oxidation in the open pit and underground areas. Wendako Creek downstream of the Anawe North dump also showed more significant elevated results from minor sulphide oxidation within the dump. PJV/ENV 1/10 5-2

143 2009 PJV Annual Environmental Report River Monitoring 5.1 Introduction PJV has operated a comprehensive riverine monitoring program since the start of operations in 1990 to assess riverine impacts caused by the disposal of tailings and incompetent waste rock to the river system. The principal aims of the program are to verify compliance with permit conditions and to improve understanding of the impacts of riverine disposal on the Strickland River System. This in turn will enable management strategies to be developed to reduce riverine impacts. This section overviews the 2009 riverine monitoring programs and discusses data trends. Water quality and bed sediment samples for trace metals downstream of the Porgera mine were collected monthly at a number of downstream monitoring locations, including the Lagaip River at SG2 and Wankipe, the upper Strickland River at the SG3 compliance monitoring station, and the control reference sites on the upper Lagaip River, upstream of the Porgera/ Lagaip junction, and away from the main river system at Pori River, Ok Om and Kuru River. It was only possible to obtain one set of samples from the Porgera River at SG1 in 2009 due to ongoing Landowner concerns. Lower Strickland River sites at Bebelubi, SG4 and SG5 were sampled quarterly as well as the control sites at Baia River and Tomu River. SG6 on the Herbert River was also sampled. These locations are shown on the following map, which is a reproduction of Figure 2-1 for convenience. For each monitoring location, water quality samples were analysed for dissolved and total concentrations of arsenic, cadmium, chromium, copper, iron, lead, mercury, nickel, silver and zinc, as well as for ph and total suspended solids TSS. Bed sediment samples taken at various locations along the river system were analysed for the above metals, plus selenium, in the minus 63 micron <63µm size fraction and for total metals. Samples for dissolved metals were filtered in the PJV Environment Lab at Porgera using a 0.45µm acid-washed polycarbonate filter and holder 250mL, and preserved with ultra-pure grade nitric acid before shipment. Samples for total metals were neither filtered nor preserved before shipment. All samples were sent to the National Measurement Institute NMI laboratory in Sydney. The sediment samples were collected as duplicates in the field then returned to the onsite laboratory where they were temporarily stored in a refrigerator before shipment to NMI. A duplicate sample was included with every seven samples sent to NMI, and the QA/QC on these batches was conducted by NMI. 5.2 Trace Metals in the Downstream River System Dissolved and total trace metal results are summarized in both graphical box plot and tabular statistical summary forms in this section. In addition, dissolved annual mean concentrations for metals for 2009 are presented as data maps to indicate the extent and effectiveness of dissolved metals decrease downstream of the Porgera mine. The boxplot graphical presentations show the 2009 results as boxplots of the trace metals and physical parameter at the various downstream monitoring sites. A brief description of how to interpret box plots is presented as Appendix 1. PJV/ENV 1/10 5-3

144 2009 PJV Annual Environmental Report River Monitoring In general, a decreasing trend in dissolved and total trace metal concentrations that occurs downstream of the mine is an indication of increased river flow and sediment accumulation, and hence dilution of these potential contaminants, as tributaries progressively join the main river system. Tabular presentations are restricted to the results for dissolved and total trace metals at the various monitoring locations over time, from 2000 to Detailed results and discussions for the trace metals and physical parameters at the downstream monitoring sites are presented in the following sub-sections. PJV/ENV 1/10 5-4

145 2009 PJV Annual Environmental Report River Monitoring OK OM RIVER OK OM CONTROL STN Sisimin LAGAIP Wankipe Wagiba SG2 SG3 Tumbudu River Pori River River Porgera SG1 PORGERA MINE Line RIVER OK TEDI Gaiabi Tinahai Transmission Omemi Komagato Hides Ok Tedi River KIUNGA Tegena RIVER Bebelubi Baia River Buseki Upovia Upovia LAKE MURRAY Kukudobi Duale Wikikama Tiumsiniwam Nomad River Undugumbi Tomu River SG4 FLY Boboa Herbert River STRICKLAND SG6 SG5 SG7 INDONESIA PAPUA NEW GUINEA RIVER SG8 PURUTU DARU GULF OF PAPUA Strickland River system showing downstream monitoring locations and Lake Murray. PJV/ENV 1/10 5-5

146 2009 PJV Annual Environmental Report River Monitoring Arsenic in the River System During 2009, all dissolved arsenic concentrations were low and well below the SG3 compliance of 50µg/L at all downstream monitoring sites. Total arsenic concentrations showed a strong downward trend from SG1 to SG5 due mainly to the dilution effect of downstream tributaries Figure 5-1A. Concentrations of dissolved and total arsenic, from 2005 to 2009 Figure 5-1B, showed similar trends to those obtained in From the results for 2000 to 2009 in Table 5-1, the mean annual dissolved arsenic concentration remained relatively low at SG1 compared to previous years. Total arsenic concentrations at downstream sites were consistent with previous years except for SG1 which was higher than recent years. % && '& & " # # " " # # " Figure 5-1A Arsenic concentrations at downstream locations during # %&&'& & " " # " # # " Figure 5-1B Arsenic concentrations at downstream locations from 2005 to PJV/ENV 1/10 5-6

147 2009 PJV Annual Environmental Report River Monitoring Table 5-1 Mean annual arsenic concentrations at downstream sites from 2000 to 2009 µg/l. Dissolved arsenic Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 1.0 Total arsenic Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 1.0 PJV/ENV 1/10 5-7

148 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe "*"+, " Tiumsinawam # # " Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-1C Mean dissolved arsenic concentrations at downstream sites from The above graph within Figure 5-1C shows the decrease in the mean dissolved arsenic concentrations at the various monitoring stations downstream of the mine. All concentrations are very low and well below the SG3 compliance criterion of 50µg/L. PJV/ENV 1/10 5-8

149 2009 PJV Annual Environmental Report River Monitoring Cadmium in the River System Dissolved cadmium concentrations for 2009 were low and well below the compliance criterion of 1µg/L. The total metal concentration decrease from SG1 to SG5 was due to dilution effects from natural sediments with distance downstream of the mine Figure 5-2A. The corresponding graphs for show similar trends to those for From Table 5-2, the mean annual dissolved value for 2009 increased noticeably over recent years and was more in line with values obtained in the early 2000s. The mean annual dissolved and total cadmium concentrations from 2000 to 2009 beyond SG1 have shown little variation over the years " # " % && '' ' +. " # # " Figure 5-2A Cadmium concentrations at downstream locations during "- %&&'' " ' #- # #- # - - # " # " Figure 5-2B Cadmium concentrations at downstream locations from 2005 to PJV/ENV 1/10 5-9

150 2009 PJV Annual Environmental Report River Monitoring Table 5-2 Mean annual cadmium values at downstream sites from 2000 to 2009 µg/l Dissolved cadmium Porgera at SG Lagaip at SG Lagaip at Wankipe < Strickland at SG Strickland at Bebelubi Strickland at SG < < Strickland at SG Upper Lagaip <0.1 <0.1 < Pori River Ok Om <0.1 < Kuru River Baia River Tomu River SG6 0.2 Total cadmium Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 0.2 < = Limit of Reporting National Measurement Institute, Sydney PJV/ENV 1/

151 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe "- "*"+, "- #- #- Tiumsinawam - - # " Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-2C Mean dissolved cadmium concentrations at downstream sites from The graph within Figure 5-2C shows a rapid decrease in the dissolved cadmium concentration at SG1 to considerably lower values at monitoring stations further downstream. All dissolved cadmium concentrations downstream of SG1 are at or near the detection limit of 0.2µg/L. The concentration at SG3 is well below the compliance criterion of 1µg/L. PJV/ENV 1/

152 2009 PJV Annual Environmental Report River Monitoring Chromium in the River System Dissolved chromium concentrations during 2009 were very low with all values at or below the detection limit of 1µg/L. Total chromium values decreased noticeably downstream of SG2. The Kuru River control site showed anomalously higher readings in that area for reasons unknown Figure 5-3A. The results for in Figure 5-3B were similar to those for Mean annual dissolved chromium concentrations from 2000 to 2009 Table 5-3 remained low over the 10-year period. #- #-" # %&&'/ # ". " # / # " Figure 5-3A Chromium concentrations at downstream locations during %&&'/ # / " " # # " # " Figure 5-3B Chromium concentrations at downstream locations from 2005 to PJV/ENV 1/

153 2009 PJV Annual Environmental Report River Monitoring Table 5-3 Mean annual chromium concentrations at downstream sites from 2000 to 2009 all results in µg/l. Dissolved chromium Porgera at SG <1 <1 <1 nd Lagaip at SG <1 <1 <1 <1 Lagaip at Wankipe 0.7 <1 < <1 <1 <1 <1 <1 Strickland at SG <1 <1 <1 <1 <1 <1 <1 <1 Strickland at Bebelubi 1 <1 <1 Strickland at SG4 < <1 <1 <1 <1 Strickland at SG5 0.2 <1 <1 <1 <1 <1 Upper Lagaip < <1 <1 <1 <1 Pori River 0.6 <1 <1 <1 1.1 Ok Om 0.8 <1 0.9 < <1 <1 <1 <1 Kuru River <1 1.1 Baia River <1 <1 <1 Tomu River 0.2 <1 <1 <1 <1 SG6 <1 Total chromium Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 1.0 nd = no data available; < = Limit of Reporting National Measurement Institute, Sydney PJV/ENV 1/

154 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe "- "*"+, #- #- - Tiumsinawam - # " Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-3C Mean dissolved chromium concentrations at downstream sites from The above graph within Figure 5-3C showed consistently low values for dissolved chromium concentrations downstream of Porgera. All values shown for 2009 are well below the SG3 compliance criterion of 10µg/L. PJV/ENV 1/

155 2009 PJV Annual Environmental Report River Monitoring Copper in the River System Both dissolved and total copper concentrations during 2009 showed relatively higher results for SG1 but declined rapidly downstream at SG2 and beyond Figure 5-4A. The results for Figure 5-4B were much the same. From Table 5-4, the 2009 mean dissolved concentrations at SG1 and SG2 were very much lower than in previous years, most likely due to the addition of a Cyanide Destruction Unit within the Process Plant. All other 2009 results for both dissolved and total concentrations were consistent with previous years. +. " # %&&' "" # " # " # " Figure 5-4A Copper concentrations at downstream locations during "" %&&' " " " # # # # " # " Figure 5-4B Copper concentrations at downstream locations from PJV/ENV 1/

156 2009 PJV Annual Environmental Report River Monitoring Table 5-4 Mean annual copper concentrations at downstream sites from 2000 to 2009 all results in µg/l. Dissolved copper Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi <1 Strickland at SG Strickland at SG <1 Upper Lagaip <1 Pori River <1 Ok Om <1 Kuru River <1 Baia River <1 Tomu River <1 SG6 <1 Total copper Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 <1 < = Limit of Reporting National Measurement Institute, Sydney PJV/ENV 1/

157 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe " "" "*"+, # # Tiumsinawam # " Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-4C Mean dissolved copper concentrations at downstream sites from The graph within Figure 5-4C shows a dramatic decrease in concentrations of dissolved copper beyond SG1, which is influenced by mine discharge. PJV/ENV 1/

158 2009 PJV Annual Environmental Report River Monitoring Iron in the River System Dissolved iron concentrations downstream of the mine were relatively low and showed no obvious trend during Total iron declined noticeably compared to the various other downstream monitoring sites Figure 5-5A. Similar results were obtained from 2005 to From Table 5-5, both mean annual dissolved and total iron concentrations downstream of the mine have varied noticeably over the years with no distinct trends. % && ' " " # # # " # " Figure 5-5A Iron concentrations at downstream monitoring sites during %&&' " " # # # " # " Figure 5-5B Iron concentrations at downstream locations from 2005 to PJV/ENV 1/

159 2009 PJV Annual Environmental Report River Monitoring Table 5-5 Mean annual iron concentrations at downstream sites from 2000 to 2009 all results in µg/l. Dissolved iron Porgera at SG nd Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 39 Total iron Porgera at SG nd Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG nd = no data available PJV/ENV 1/

160 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe #" "*"+, # Tiumsinawam " # " Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-5C Dissolved Iron mean concentrations at downstream sites from The above graph within Figure 5-5C shows that dissolved iron is widespread throughout the Strickland River system and its tributaries. Catchment areas that are unaffected by mine operations, such as Upper Lagaip River, Tomu and Ok Om, generally showed higher levels than downstream of the mine. PJV/ENV 1/

161 2009 PJV Annual Environmental Report River Monitoring Lead in the River System Dissolved lead concentrations for 2009 at downstream monitoring stations were at or below the detection limit of 0.5µg/L. The total lead concentration at SG1 was relatively high but declined rapidly at SG2 and beyond due to the dilution effect of downstream tributaries Figure 5-6A. Similar patterns were seen for the From Table 5-6, mean annual dissolved and total lead concentrations for showed similar results to previous years # " %&&''. " # # " ' Figure 5-6A Lead concentrations at downstream locations during Lead levels Dissolved lead Total lead µg/l # " # STATIONS " 0 Figure 5-6B Lead concentrations at downstream locations from 2005 to PJV/ENV 1/

162 2009 PJV Annual Environmental Report River Monitoring Table 5-6 Mean annual lead concentrations at downstream sites from 2000 to 2009 all results in µg/l. Dissolved lead Porgera at SG <0.5 Lagaip at SG <0.5 <0.5 <0.5 Lagaip at Wankipe <0.5 Strickland at SG <0.5 Strickland at Bebelubi <0.5 Strickland at SG <0.5 Strickland U/S Oxbow # 5 <0.5 Oxbow # 3 <0.5 Strickland U/S Herbert <0.5 Strickland at SG <0.5 Zongamange <0.5 Avu <0.5 Upper Lagaip <0.5 Pori River <0.5 Ok Om <0.5 Kuru River <0.5 Baia River <0.5 Tomu River <0.5 Herbert River at SG6 <0.5 Total lead Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland U/S Oxbow # 5 18 Oxbow # Strickland U/S Herbert 13 Strickland at SG Zongamange <0.5 Avu <0.5 Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River Herbert River at SG6 0.6 nd= no data available, < = Limit of Reporting National Measurement Institute, Sydney PJV/ENV 1/

163 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe #- "*"+, #- #-" # Tiumsinawam -" - # " Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-6C Mean dissolved lead concentrations at downstream sites from The graph within Figure 5-6C showed varied results across the river catchments downstream of Porgera. The highest value was for the control site, Pori, which is not influenced by mine discharge, and the reason why the level at Wankipe is higher than SG1 is not clear. All mean values shown in Figure 5-6C are well below the SG3 compliance criterion of 3µg/L. PJV/ENV 1/

164 2009 PJV Annual Environmental Report River Monitoring Mercury in the River System Dissolved mercury concentrations at all downstream monitoring locations for 2009 were at or below the detection limit of 0.1µg/L Figure 5-7A. Total mercury concentrations were very low except for SG2 and Wankipe Figure 5-7A which is most likely due to mercury spilled from alluvial mining activities along the Porgera River downstream of the mine. Dissolved mercury concentrations for Figure 5-7B were at or near the detection limit while the total values were similar to those for Mean annual dissolved concentrations for 2009 Table 5-7 were below detection levels at all locations while total values were similar to those in previous years. # -# -#" -# -. - % && ' 0 0 #- # " #- #- #-" # " - # " Figure 5-7A Mercury concentrations at downstream locations during M erucry levels %&&' µg/l SG1 SG2 Wan kipe SG3 Strick/Bebel ubi SG4 SG5 Upp er La gaip Pori Ri ver Ok Om Kuru River Baiya River Tomu River SG6 5 0 STATIONS SG1 SG2 Wankipe SG3 Strick/Bebelubi SG4 SG5 Upp er La gaip Pori River Ok Om Kuru River Baiya River Tomu River SG6 Figure 5-7B Mercury concentrations at downstream locations from 2005 to PJV/ENV 1/

165 2009 PJV Annual Environmental Report River Monitoring Table 5-7 Mean annual mercury concentrations at downstream monitoring sites from 2000 to 2009 all results in µg/l. Dissolved mercury Porgera at SG <0.1 <0.1 <0.1 nd Lagaip at SG <0.1 <0.1 <0.1 <0.1 Wankipe <0.1 <0.1 <0.1 <0.1 Strickland at SG3 0.2 <0. <0. <0. <0. <0. <0.1 <0.1 <0.1 <0.1 Strickland at Bebelubi <0.1 <0.1 <0.1 Strickland at SG <0.1 <0.1 <0.1 <0.1 Strickland U/S Oxbow # 5 <0.1 Oxbow # 3 <0.1 Strickland U/S Herbert <0.1 Strickland at SG <0.1 <0.1 <0.1 Zongamange <0.1 Avu <0.1 Upper Lagaip <0.1 <0.1 <0.1 Pori River <0.1 <0.1 <0.1 Ok Om <0.1 <0.1 <0.1 Kuru River <0.1 <0.1 <0.1 Baia River <0.1 <0.1 <0.1 Tomu River <0.1 <0.1 <0.1 Herbert River at SG6 <0.1 Total mercury Porgera at SG nd Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi <0.1 Strickland at SG <0.1 Strickland U/S Oxbow # 5 <0.1 Oxbow # 3 <0.1 Strickland U/S Herbert <0.1 Strickland at SG <0.1 Zongamange <0.1 Avu <0.1 Upper Lagaip <0.1 Pori River <0.1 Ok Om Kuru River Baia River <0.1 Tomu River <0.1 Herbert River at SG6 <0.1 nd = no data available; < = Limit of Reporting National Measurement Institute, Sydney PJV/ENV 1/

166 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe %% "*"+, " Tiumsinawam # # " 0 Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-7C Mean total mercury concentrations at downstream sites from The graph within Figure 5-7C shows the consistent low values for total mercury concentrations beyond SG1 downstream of the Porgera mine. Dissolved mercury is not shown because all levels, including SG1, are at or near the detection limit. PJV/ENV 1/

167 2009 PJV Annual Environmental Report River Monitoring Nickel in the River System Dissolved nickel concentrations were at or below the detection limit at monitoring stations below SG2 during 2009 and well below compliance criterion of 50µg/L. The total nickel concentration at SG1 was relatively high but the level at other stations decreased rapidly further downstream. The Kuru River control showed anomalously high values Figure 5-8A. With the exception of SG1, dissolved nickel values for were at or near the detection limit Figure 5-8B while total values were similar to those obtained for Mean annual dissolved and total nickel values for 2009 were consistent with those obtained in previous years Table 5-8. & - - "- "- #- #- %&& ' # " +. " # # " Figure 5-8A Nickel concentrations at downstream locations during Nickel levels Dissolved nickel 5000 Total nickel µg/l SG1 SG2 Wanki pe SG 3 Strick/Bebelubi SG4 SG5 Upper Lagaip Pori River Ok Om Kuru River Baiya River T omu Ri ver SG STATIONS SG1 SG2 Wanki pe SG3 Strick/Bebelubi SG4 SG 5 Upper Lagaip Pori River Ok Om Kuru River Baiya River To mu River SG6 Figure 5-8B Nickel concentrations at downstream locations from 2005 to PJV/ENV 1/

168 2009 PJV Annual Environmental Report River Monitoring Table 5-8 Mean annual nickel concentrations at downstream sites from 2000 to 2009 all results in µg/l. Dissolved nickel Porgera at SG nd Lagaip at SG Lagaip at Wankipe <1 Strickland at SG <1 Strickland at Bebelubi 1 1 <1 Strickland at SG <1 Strickland at SG <1 Upper Lagaip <1 Pori River <1 Ok Om <1 Kuru River <1 Baia River 1 1 <1 Tomu River <1 SG6 <1 Total nickel Porgera at SG Lagaip at SG Strickland at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 <1 nd = no data available; < = Limit of Reporting National Measurement Institute, Sydney PJV/ENV 1/

169 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe # & "*"+, #" # Tiumsinawam " # " Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-8C Mean dissolved nickel concentrations at downstream sites from The graph within Figure 5-8C indicates a relatively high dissolved nickel concentration at SG1 with a sharp decrease at other monitoring stations further downstream. All mean values, including SG1, are well within the SG3 compliance criterion of 50µg/L. PJV/ENV 1/

170 2009 PJV Annual Environmental Report River Monitoring Silver in the River System Dissolved silver concentrations for 2009 were very low with all results at or below the detection limit, and well below the SG3 compliance of 4µg/L Figure 5-9A. Total silver concentrations decreased rapidly from SG1 to other downstream monitoring locations due to the dilution effect of downstream tributaries Figure 5-9A. For , dissolved silver values were at or below the detection limit except for SG1. The downward trend for total values for was similar to those obtained for Mean annual dissolved and total silver concentrations for 2009 Table 5-9 showed little variation with those of previous years with the exception of total silver at SG1. %&&'& & -" # #" -"" # -" -#. -# # " " # " Figure 5-9A Silver concentrations at downstream locations during "- % && '& & # #" # "- #- #- - - # " " # " Figure 5-9B Silver concentrations at downstream locations from 2005 to PJV/ENV 1/

171 2009 PJV Annual Environmental Report River Monitoring Table 5-9 Mean annual silver concentrations at downstream sites from 2000 to 2009 results in µg/l. Dissolved silver Porgera at SG nd Lagaip at SG <0.2 Lagaip at Wankipe <0.2 Strickland at SG <0.2 Strickland at Bebelubi <0.2 Strickland at SG <0.2 Strickland at SG <0.2 Upper Lagaip <0.2 Pori River <0.2 Ok Om <0.2 Kuru River <0.2 Baia River <0.2 Tomu River <0.2 SG6 <0.2 Total silver Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG <0.2 Upper Lagaip Pori River <0.2 Ok Om <0.2 Kuru River Baia River <0.2 Tomu River <0.2 SG6 <0.2 nd = no data available; < = Limit of Reporting National Measurement Institute, Sydney PJV/ENV 1/

172 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe - "*"+, " Tiumsinawam -# - # " 0 Note: Upper Lagaip, Pori, OkOm, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-9C Mean dissolved silver concentrations at downstream sites from The above graph within Figure 5-9C shows the very low dissolved silver concentrations downstream of the Porgera mine, and well below the SG3 compliance criterion of 4µg/L. PJV/ENV 1/

173 2009 PJV Annual Environmental Report River Monitoring Zinc in the River System Dissolved zinc concentrations for 2009 decreased steadily downstream of the mine. Total zinc concentrations declined rapidly beyond SG1 due to the dilution effect of downstream tributaries Figure 5-10A. For , dissolved and total values showed similar trends to those for 2009 Figure 5-10B. Mean annual dissolved and total zinc concentrations were in line with previous years Table ' " " %&&'1 # #" # 1 # # # " " # " Figure 5-10A Zinc concentrations at downstream monitoring sites during ' # %&&'1 1 " " # " # # " Figure 5-10B Zinc concentrations at downstream locations from 2005 to PJV/ENV 1/

174 2009 PJV Annual Environmental Report River Monitoring Table 5-10 Mean annual zinc concentrations at downstream sites from 2000 to 2009 all results in µg/l. Dissolved zinc Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 6 Total zinc Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip Pori River Ok Om Kuru River Baia River Tomu River SG6 43 PJV/ENV 1/

175 2009 PJV Annual Environmental Report River Monitoring OK Om Upper Lagaip SG3 Wankipe SG2 SG1 Porgera Tailings Ex-pipe "*"+, " Tiumsinawam # # " 0 Note: Upper Lagaip, Pori, Ok Om, Kuru, Baia and Tomu are monitoring control sites not affected by the Porgera mine. Figure 5-10C Dissolved Zinc mean concentrations at downstream sites from The graph within Figure 5-10C indicates the rapid decline in concentrations of dissolved zinc downstream of SG1 for The Upper Lagaip control site shows a surprisingly high zinc value. Values at all sites, including SG1, are below the SG3 compliance criterion of 50µg/L. PJV/ENV 1/

176 2009 PJV Annual Environmental Report River Monitoring 5.3 Physicochemical Parameters in the Downstream River System ph Measurement The 2009 median ph values at monitoring and control sites downstream of the mine are shown in Figure The variability is caused mainly by the differing water quality of the tributaries as they enter the main river system. The ph range is indicative of natural river values throughout the region. Mean ph values obtained from 2000 to 2009 Table 5-11 indicate the relatively consistent, slightly alkaline nature of the entire Porgera-Lagaip-Strickland River system downstream of the Porgera mine. - " - " % # " Figure 5-11 ph measurements at downstream monitoring sites during Table 5-11 Mean annual ph measurements at downstream sites from 2000 to 2009 all results in ph units. Location Porgera at SG nd Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip River* Pori River* Ok Om* Kuru River* Baia River* Tomu River* nd = no data available; * = control sites PJV/ENV 1/

177 2009 PJV Annual Environmental Report River Monitoring Total Suspended Solids TSS in the River System Table 5-12 shows the general decrease in TSS in the Strickland River system from 2000 to 2009 from the mine site Porgera at SG1 to SG5. The decrease results from the deposition of coarser suspended material as the river profile flattens in its lower reaches, and as a result of natural dilution from various tributaries along the river system. Table 5-12 Mean total suspended solids concentrations at downstream sites from 2000 to 2009 all results in mg/l Location Porgera at SG Lagaip at SG Lagaip at Wankipe Strickland at SG Strickland at Bebelubi Strickland at SG Strickland at SG Upper Lagaip River* Pori River* Ok Om* Kuru River* Baia River* Tomu River* * = control sites PJV/ENV 1/

178 2009 PJV Annual Environmental Report River Monitoring 5.4 Bed Sediment Sampling in the Downstream River System Bed sediment samples were collected during 2009 at the main downstream monitoring locations along the Porgera/Lagaip/Strickland River system using a plastic scoop to skim off the top 2 cm of recently-deposited sediment from sandbars or from river banks. The sediment samples were collected as duplicates in the field then returned to the onsite laboratory where they were temporarily stored in a refrigerator before shipment to NMI. A duplicate sample was included with every seven samples sent to NMI, and the QA/QC on these batches was conducted by NMI. The bed sediment samples were taken monthly at SG2, Wankipe and SG3, as well as the Upper Lagaip, Pori, Ok Om and Kuru control sites. Only one sediment samples was collected at SG1 due to Landowner concerns. Further downstream, bed sediment samples were taken on a 2-monthly basis at Bebelubi, SG4 and SG5, including the Baia and Tomu control sites. The analytical results are presented in Figure Metal contents in both the <63µm and total fractions of the bed sediments showed considerable variability in trace metal content from the mine site to SG5 in the Lower Strickland region. In general, the concentrations of trace metals should show a downward trend downstream of Porgera as mine-derived sediments become diluted with natural sediments along the course of the Lagaip/Strickland river system and their tributaries. However, such a trend is often difficult to determine because of the relatively low number of samples taken during the year, and the existence of background levels of metals in natural sediments derived from various sources within the river catchment. With some metals, the Baia and Tomu control sites appear to be influenced by ancient volcanic activity to the east, especially Mt Bosavi in the case of Tomu. % " 2&*3 " 2&*4 " " # # # # # " * # " Figure 5-12 Metal content in the <63µm and total size fraction of bed sediment samples at downstream sites during PJV/ENV 1/

179 2009 PJV Annual Environmental Report River Monitoring % 5'*3 # 5'*4 " # # " " * # " % " 5*3 " 5*4 # " # # # # " * # " Figure 5-12 cont. Metal content in the <63µm and total size fraction of bed sediment samples at downstream sites during PJV/ENV 1/

180 2009 PJV Annual Environmental Report River Monitoring ""% 5*3 5*4 " " # # " # " # * # " % " 4*3 + 4*4 #. # # " " * # " Figure 5-12 cont. Metal content in the <63µm and total size fraction of bed sediment samples at downstream sites during PJV/ENV 1/

181 2009 PJV Annual Environmental Report River Monitoring % + *3 *4. " " # # " # * # " # % # " -# Figure 5-12 cont. 6*3 # " " -" * 6*4 # " Metal content in the <63µm and total size fraction of bed sediment samples at downstream sites during PJV/ENV 1/

182 2009 PJV Annual Environmental Report River Monitoring &% 7*3 " 7*4 " " # # # # " * # " % "- *3 "-" *4 "- #- #- - Figure 5-12 cont. # " #-. #- #-" # * # " Metal content in the <63µm and total size fraction of bed sediment samples at downstream sites during PJV/ENV 1/

183 2009 PJV Annual Environmental Report River Monitoring % 2*3-2*4 - - " # # " "- "- #- #- - * # " '% " " # # # Figure 5-12 cont. 8*3 " # # # #" # " * # 8*4 " Metal content in the <63µm and total size fraction of bed sediment samples at downstream sites during In general, the finer sediment fraction for metal-bearing sediments possesses more downstream mobility from river turbulence, and is likely to be transported more readily to the Fly River delta; however, these sediments are also more susceptible to overbank deposition on the floodplain during high river flows. PJV/ENV 1/

184 2009 PJV Annual Environmental Report River Monitoring From Figure 5-12, the <63µm and total concentrations for most metals showed, as expected, a downward trend with increasing distance downstream of the mine. However, chromium showed no distinct trend for both the finer and total fractions, while nickel showed no distinct trend in the finer fraction only. Table 5-13 Mean metal concentrations in the <63µm fraction at downstream sites. All sites from SG1 to SG3 including the control sites are sampled monthly. Those further downstream are sampled every two months. Results are in mg/kg. Station Year As Cd Cr Cu Fe Pb Hg Ni Se Ag Zn SG SG Wankipe SG ANZECC/ARMCANZ trigger value Bebelubi PJV/ENV 1/

185 2009 PJV Annual Environmental Report River Monitoring Table 5-13 cont. Mean metal concentrations in the <63µm fraction at downstream sites. All sites from SG1 to SG3 including the control sites are sampled monthly. Those further downstream are sampled every two months. Results are in mg/kg. Station Year As Cd Cr Cu Fe Pb Hg Ni Se Ag Zn SG SG Upper nd 85 Lagaip* Pori* Ok Om* Kuru* Notes: * = control site; nd = no data PJV/ENV 1/

186 2009 PJV Annual Environmental Report River Monitoring Table 5-13 cont. Mean metal concentrations in the <63µm fraction at downstream sites. All sites from SG1 to SG3 including the control sites are sampled monthly. Those further downstream are sampled every two months. Results are in mg/kg. Station Year As Cd Cr Cu Fe Pb Hg Ni Se Ag Zn Baia* Tomu* SG From Table 5-13, the mean concentrations of arsenic, cadmium, lead, silver and zinc in the <63 µm sediment fraction over the years have consistently shown a decrease with distance downstream of SG1. This trend is not obvious for results presented for chromium, copper, mercury, nickel and selenium. PJV/ENV 1/

187 2009 PJV Annual Environmental Report River Monitoring Table 5-14 Mean total metal content of bed sediments at downstream sites. All sites from SG1 to SG3 including the control sites are sampled monthly. Those further downstream are sampled every two months. Results are in mg/kg. Station Year As Cd Cr Cu Fe Pb Hg Ni Se Ag Zn SG SG Wankipe SG Bebelubi PJV/ENV 1/

188 2009 PJV Annual Environmental Report River Monitoring Table 5-14 cont. Mean total metal content of bed sediments at downstream sites. All sites from SG1 to SG3 including the control sites are sampled monthly. Those further downstream are sampled every two months. Results are in mg/kg. Station Year As Cd Cr Cu Fe Pb Hg Ni Se Ag Zn SG SG Upper Lagaip* Pori* Ok Om* Kuru* PJV/ENV 1/

189 2009 PJV Annual Environmental Report River Monitoring Table 5-14 cont. Mean total metal content of bed sediments at downstream sites. All sites from SG1 to SG3 including the control sites are sampled monthly. Those further downstream are sampled every two months. Results are in mg/kg. Station Year As Cd Cr Cu Fe Pb Hg Ni Se Ag Zn Baia* Tomu* SG6 Herbert Notes: * = control site; nd = no data As with the results shown for the finer fraction in Table 5-13, the mean total concentrations of arsenic, cadmium, lead, silver and zinc are similar and have consistently shown a decrease with distance downstream of SG1 Table This trend is not obvious for results presented for chromium, copper, mercury, nickel and selenium. PJV/ENV 1/

190 2009 PJV Annual Environmental Report River Monitoring 5.5 Local Creeks Water Quality Monitoring The following local creeks, situated within the Special Mining Lease SML area, are monitored regularly each month for dissolved and total metals including arsenic, cadmium, chromium, copper, iron, lead, mercury, nickel, silver and zinc, as well as for ph, sulphate and total alkalinity: Anjolek starter dump A SDA toe Kaiya River upstream of Anjolek erodible dump Kaiya River downstream of Anjolek erodible dump Kaiya River at Yuyane Bridge Yunarilama at Portal for drainage tunnel 28 Level underground water discharge at adit Yakatabari Creek downstream of 28 Level discharge Kogai stable dump toe area Wendako Creek downstream of Anawe North stable dump Aipulungu River at road bridge near Porgera Station Aipulungu River upstream of lime plant and quarry Lime plant discharge upstream of Aipulungu River The Kaiya River upstream of the Anjolek erodible dump is a control site for the waste dump fluvial. Within the mine s influence, the Kaiya River is monitored downstream of the Anjolek erodible dump toe and further downstream at Yuyane. Yakatabari Creek is monitored downstream of 28 Level underground water discharge before flowing into Kogai Creek, which then joins the Kaiya River further downstream. Kogai Creek downstream of the dump is monitored in the dump toe area. Aipulungu River is monitored upstream and downstream of the lime plant and quarry to determine its effect on water quality, especially in the vicinity of Porgera Station. The lime plant discharge before flowing into Aipulungu River is also monitored monthly. Monthly water sampling at Yunarilama commenced late in 2001 at the exit of the underground and open pit drainage tunnel. Regular monitoring was also commenced at Wendako Creek downstream of the Anawe North stable dump. Sample collection, filtration and analysis details are presented in Section 5.1, Introduction. Stream flow is measured at the time of each sample collection either by means of a spot gauging or the respective record from a stream gauging continuous recording instrument. The flow measurements concurrently with sample collection commenced in late 2003, with the objective of calculating the mass flux of contaminants discharged from waste rock dumps, the open pit and underground mines and general mine area runoff. Control sites, that are unaffected by mine operation are included to provide background water quality. The location of local monitoring sites is presented in Figure Data from monitoring in 2009 are presented in Figures 5-14 to 5-16, and compared with previous years in Table PJV/ENV 1/

191 2009 PJV Annual Environmental Report River Monitoring PJV/ENV 1/

192 2009 PJV Annual Environmental Report River Monitoring " # # & %&&'& %2 0%29 0:; 0 " ; ; ' :5 2: 2 % 029 " # * %&&'' %2 0%29 0:;0 " ; ; ' :5 2: 2 % 029 & +% +. %&&'& # #" # %&&'' " # %2 0%29 0:;0 " ; ; ' :5 2 : 2 : 2 % 029 " * %2 0%29 0:;0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-14 Results for dissolved metals in local creeks. PJV/ENV 1/

193 2009 PJV Annual Environmental Report River Monitoring. " # & "" %&&'/ %2 0%29 0 :;0 " ; ; ' :5 2: 2 % 0 29 " # * %&&' %2 0%29 0:;0 " ; ; ' :5 2: 2 % 029 & ""+%. %&&'/ %&&' " " # %2 0%29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 # * %2 0%29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-14 cont. Results for dissolved metals in local creeks. PJV/ENV 1/

194 2009 PJV Annual Environmental Report River Monitoring & " %&&' %&&'' " # " # %2 0%29 0:; 0 " ; ; ' :5 2 : 2 % 029 # %2 0 %29 * 0:; 0 " ; ; ' :5 2 : 2 % 0 29 &+% %&&' " %&&''. # # " # %2 0%29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 * %2 0%29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-14 cont. Results for dissolved metals in local creeks. PJV/ENV 1/

195 2009 PJV Annual Environmental Report River Monitoring & & -# %&&'0 #" %&&' # -#" -# -. - %2 0 %29 0:;0 " ; ; ' :5 2 : 2 % 029 " * %2 0 %29 0:;0 " ; ; ' :5 2 : 2 % 029 & &+% - %&&'0 %&&' "- "- #- #- " - - %2 0 %29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 # * %2 0 %29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-14 cont. Results for dissolved metals in local creeks. PJV/ENV 1/

196 2009 PJV Annual Environmental Report River Monitoring & -" %&&'& # # %&&'1 -"" #" # -" -#. -# %2 0 %29 0:;0 " ; ; ' :5 2 : 2 % 029 " * %2 0 %29 0:;0 " ; ; ' :5 2 : 2 % 029 &+% -" %&&'& " %&&'1 -"" # -" # -#. -# %2 0%29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 * %2 0%29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-14 cont. Results for dissolved metals in local creeks. PJV/ENV 1/

197 2009 PJV Annual Environmental Report River Monitoring Box plots for dissolved metals in local creeks for 2009 are shown in Figure In general, concentrations of dissolved metals at most sites for 2009 were similar to those obtained over the 5-year period from The higher results for some metals at 28 Level, Yakatabari Creek and Yunarilama Portal are due to discharges from the open pit and underground workings. The levels of dissolved zinc and cadmium, in particular, from the stable dumps for 2009 when compared with the 5-year period from show that metal leaching from minor sulphide oxidation within the dumps has remained reasonably steady and is currently not a concern. Metal leaching from the Kogai Stable Dump monitored at Kogai Toe has decreased over the past 10 years, probably due to a topsoil capping being put in place and thereby minimizing sulphide oxidation. In contrast, the Anawe North Stable Dump monitored at Wendako Creek, which has yet to be capped, continues to show signs of sulphide oxidation and subsequent metal leaching cadmium and zinc. This is expected to decrease, similar to the Kogai SD, once the Anawe North is capped. PJV/ENV 1/

198 2009 PJV Annual Environmental Report River Monitoring &%% " &. ' # # %2 0%29 0:; 0 " ; ; ' :5 2 : 2 % 029 " # * %2 0%29 0:; 0 &%% +% " ; ; ' :5 2 : 2 % 029 & # ' " # " %2 0%29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 * %2 0%29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-15 Results for total metals in local creeks. PJV/ENV 1/

199 2009 PJV Annual Environmental Report River Monitoring &%% "" # / #" # " %2 0%29 0:; 0 " ; ; ' :5 2 : 2 % 029 " * %2 0%29 0:; 0 " ; ; ' :5 2 : 2 % 029 &%% ""+% " / " # " # # %2 0%29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 # * %2 0 %29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-15 cont. Results for total metals in local creeks. PJV/ENV 1/

200 2009 PJV Annual Environmental Report River Monitoring &%% #" # ' " " # %2 0%29 0:; 0 " ; ; ' :5 2 : 2 % 029 * %2 0%29 0:; 0 " ; ; ' :5 2 : 2 % 029 &%%+% " #" # ' " # # " %2 0%29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 * %2 0 %29 0 :;0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-15 cont. Results for total metals in local creeks. PJV/ENV 1/

201 2009 PJV Annual Environmental Report River Monitoring &%% & +. " # %2 0%29 0:; 0 0 " ; ; ' :5 2 : 2 % " # %2 0 %29 * 0:; 0 " ; ; ' :5 2 : 2 % 0 29 &%% &+% " 0 # " #" # # # %2 0%29 0:; 0 " ; ; ' :5 2 : 2: 2 % 0 29 " * %2 0%29 0:; 0 " ; ; ' :5 2 : 2: 2 % 0 29 Figure 5-15 cont. Results for total metals in local creeks. PJV/ENV 1/

202 2009 PJV Annual Environmental Report River Monitoring &%% # & # 1 #" # " %2 0 %29 0:; 0 " ; ; ' :5 2 : 2 % 0 29 " * %2 0 %29 0:; 0 " ; ; ' :5 2 : 2 % 029 &%%+% & 1 # " #" # # # " %2 0%29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 * %2 0%29 0:; 0 " ; ; ' :5 2 : 2 : 2 % 029 Figure 5-15 cont. Results for total metals in local creeks. PJV/ENV 1/

203 2009 PJV Annual Environmental Report River Monitoring From Figure 5-15, total metal values recorded for all local sites during 2009 were, in general, similar to those recorded for past five years from The box plots clearly show the predominance of total metals coming from the open pit and underground areas via 28 Level, Yakatabari Creek and Yunarilama Portal. All total metal values from these areas are relatively low and within acceptable limits. Dissolved metal concentrations in local creeks decrease rapidly downstream due to river dilution from tributaries and adsorption onto natural sediments. However, total metals ie metal-bearing total suspended solids mainly decrease by natural sediment dilution from landslides throughout the catchment and from sediment-laden tributaries of the Porgera/Lagaip/ Strickland River system. PJV/ENV 1/

204 2009 PJV Annual Environmental Report River Monitoring #" &" ## " % # +. %2 0% 29 0:;0 " ; ; ' :5 2: * 2 % 0 29 # &"+% #" ## " % # +. %2 0%29 0:; 0 " ; ; ' :5 2: 2: * 2 % 029 Figure 5-16 Major water quality parameters of local creeks PJV/ENV 1/

205 2009 PJV Annual Environmental Report River Monitoring, "% " " # # %2 0%29 0:; 0 " ; ; ' :5 2: * 2 % 029, "%% " " # # %2 0%29 0:;0 " ; ; ' :5 2: 2: * 2 % 029 Figure 5-16 cont. Major water quality parameters of local creeks PJV/ENV 1/

206 2008 PJV Annual Environmental Report River Monitoring " %&% # # %2 0%29 0:; 0 " ; ; ' :5 2: * 2 % 029 %&%+% " # # %2 0%29 0:;0 " ; ; ' :5 2: 2: * 2 % 029 Figure 5-16 cont. Major water quality parameters of local creeks PJV/ENV 1/

207 2008 PJV Annual Environmental Report River Monitoring Loca l cre e ks TS S le ve ls in 2009 mg/l " # SDA Toe Kaiya D/S A nj Yuyane 28 Level Yakatabari Yunarilama Wendako Kogai Toe Culvert Stn Waile Limeplant S ITES Aipulungu Creek U/S W aile Dam Kaiya U/S Anj Pongema Loca l cre e ks TSS le ve ls from 2005 to mg/l SDA Toe Kaiya D/S Anj Yuyane 28 Level Yakatabari Yunarilama Wendako Kogai Toe Culvert Stn W aile Limeplant SITES A ipulungu U/S Waile Dam Kaiya U/S Anj Pongema Figure 5-16 cont. Major water quality parameters of local creeks PJV/ENV 1/

208 2008 PJV Annual Environmental Report River Monitoring Data from Figure 5-16 show that ph values for 2009 were generally consistent in the local creeks. The exception was the stream flowing from the lime plant, which was moderately alkaline. Alkalinity measurements from the lime plant showed a range of results ph depending on plant operating conditions. Sulphate results showed elevated readings for water released from the SDA toe, Yakatabari Creek and Yunarilama Portal as a result of minor sulphide oxidation in the open pit and underground areas. Wendako Creek downstream of the Anawe North dump also showed more significant elevated results from minor sulphide oxidation within the dump. From Table 5-15, mean annual water quality data for local creeks collected from 2005 to 2009 showed the considerable variability in results. It is difficult to determine from these results whether trends are occurring over time. PJV/ENV 1/

209 2008 PJV Annual Environmental Report River Monitoring Table 5-15 Mean annual water quality data for local creeks All metals concentrations in µg/l Locations Kogai Toe Yakatabari Creek Kaiya River at Yuyane Wendako Year As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T ' Pb-D Pb-T Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T ph TSS* SO4-D* ALK-T* Note: D= dissolved metals; T= total metals; *units in mg/l PJV/ENV 1/

210 2008 PJV Annual Environmental Report River Monitoring Table 5-15 cont d Mean annual water quality data for local creeks All metals concentrations in µg/l Locations Kaiya D/S of Anjolek Dump Kaiya U/S of Anjolek Dump SDA Toe Yunarilama Portal Year As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T ' Pb-D Pb-T Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T ph TSS* SO4-D* ALK-T* Note: D= dissolved metals; T= total metals, * units in mg/l PJV/ENV 1/

211 2008 PJV Annual Environmental Report River Monitoring Table 5-15 cont d Mean annual water quality data, local creeks µg/l Year As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T ' Pb-D Pb-T Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T ph TSS* SO4-D* ALK-T* Note: D= dissolved metals; T= total metals; * units in mg/l PJV/ENV 1/

212 2009 PJV Annual Environmental Report River Monitoring 5.6 Quality Assurance and Quality Control Report As explained in the previous section in 4.7, this section also presents the 2009 quality assurance report for the tailings, local creeks, rivers and Lake Murray water samples. Samples were analyzed by the National Measurement Institute NMI laboratory in Sydney and were used to verify the reliability of the water quality data and the performance of the NMI laboratory during the period Introduction As explained in section 4.7.1, the same lots of reference samples were used for the tailings, local creeks, rivers and Lake Murray water samples in Data Analysis Summary of statistical data for mean, % RSD and % recovery are presented in Tables 5-16 A, B and C. All data were plotted against control charts as shown in Figure As in section only accuracy and precision calculations were done on the QC samples employed. There was good agreement between the certified and analytical means of all metals. All metals showed good recoveries and were within acceptable ranges 75%-120% except for Hg, 69% and 70% for the first and last QC samples respectively. The % RSD for most metals were between % except Hg. Overall 97.5% of the QC data fall within the acceptable control limits within ±3SD while 2.5% of the data fall outside of the limits. The overall statistical data for the QC samples analyzed in 2009 demonstrated that the NMI laboratory performed well and results produced were acceptable with good accuracy and precision. For the purpose of this report, all water quality data for samples monitored were accepted. Table 5-16A Statistical data of certified reference material No /7 Certified values Statistics Metals Mean 1 Accepted Limits 2 Mean 3 % RSD 4 % Recov 5 ug/l ug/l ug/l As-D Cd-D Cr-D Cu-D Pb-D Hg-D Ni-D Ag-D Zn-D Mean 1 = Analytical Product Group APG certified mean, Accepted Limits 2 = APG accepted limits, Mean 3 = Analytical mean, %RSD 4 = per cent relative standard deviation, % Recov 5 = per cent recovery. PJV/ENV 1/

213 2009 PJV Annual Environmental Report River Monitoring Table 5-16B Statistical data of certified reference material No Certified values Statistics Metals Mean 1 Accepted Limits 2 Mean 3 % RSD 4 % Recov 5 ug/l ug/l ug/l As-D Cd-D Cr-D Cu-D Pb-D Hg-D Ni-D Ag-D Zn-D Mean 1 = Analytical Product Group APG certified mean, Accepted Limits 2 = APG accepted limits, Mean 3 = Analytical mean, %RSD 4 = per cent relative standard deviation, % Recov 5 = per cent recovery. Table 5-16C Statistical data of certified reference material No Certified values Statistics Metals Mean 1 Accepted Limits 2 Mean 3 % RSD 4 % Recov 5 ug/l ug/l ug/l As-D Cd-D Cr-D Cu-D Pb-D Hg-D Ni-D Ag-D Zn-D Mean 1 = Analytical Product Group APG certified mean, Accepted Limits 2 = APG accepted limits, Mean 3 = Analytical mean, %RSD 4 = per cent relative standard deviation, % Recov 5 = per cent recovery.. PJV/ENV 1/

214 2009 PJV Annual Environmental Report River Monitoring "# %%%&' %%%& ** *+'' *+ + Figure 5-17 Dissolved As trends of QC materials. PJV/ENV 1/

215 2009 PJV Annual Environmental Report River Monitoring &'& &'& &'& &'& "# %%%&' %%%& &'&** &'&* +'' &'&*+ + Figure 5-17 cont Dissolved Cd trends of QC materials. PJV/ENV 1/

216 2009 PJV Annual Environmental Report River Monitoring,&'&,&'&,&'&,&'& "# %%%&' %%%&,&'&**,&'&* +'',&'&*+ + Figure 5-17 cont Dissolved Cr trends of QC materials. PJV/ENV 1/

217 2009 PJV Annual Environmental Report River Monitoring "# %%%&' %%%& ++** ++* +'' ++*+ + Figure 5-17 cont Dissolved Cu trends of QC materials. PJV/ENV 1/

218 2009 PJV Annual Environmental Report River Monitoring "# %%%&' %%%& ** * +'' *+ + Figure 5-17 cont Dissolved Pb trends of QC materials. PJV/ENV 1/

219 2009 PJV Annual Environmental Report River Monitoring &'- *'- *'- *'- "# %%%&' %%%& *'- ** *'- * +'' *'- *+ + Figure 5-17 cont Dissolved Hg trends of QC materials. PJV/ENV 1/

220 2009 PJV Annual Environmental Report River Monitoring.... "# %%%&' %%%&.**.* +''.*+ + Figure 5-17 cont Dissolved Ni trends of QC materials. PJV/ENV 1/

221 2009 PJV Annual Environmental Report River Monitoring "# %%%&' %%%& ** * +'' *+ + Figure 5-17 cont Dissolved Ag trends of QC materials. PJV/ENV 1/

222 2009 PJV Annual Environmental Report River Monitoring 0 / / / "# %%%&' %%%& ** * +'' *+ + Figure 5-17 cont Dissolved Zn trends of QC materials. PJV/ENV 1/

223 2009 PJV Annual Environmental Report Lake Murray 6.0 LAKE MURRAY SUMMARY Some mine-derived, metal-bearing sediment from the Strickland River enters the southern end of Lake Murray via the Herbert River, and deposition can occur within the lake. This is caused by flow reversals in the Herbert River approximately 15% of the time NSR, 1995, which are caused by high levels in the Strickland River from heavy rainfall in the mountains. In 2000, a significant natural breach of the western bank of the Strickland River occurred adjacent to the Mamboi River, which flows into Lake Murray. Sediment from the Strickland River, including some mine-derived sediment, has entered the southern end of Lake Murray via the Mamboi River since that time. As a consequence of Strickland River sediment entering Lake Murray, PJV is required to monitor the lake for the duration of the Porgera mine life. PJV s monitoring activities are concerned to a large extent with the origin, movement and fate of arsenic and mercury, while other trace metals and water quality parameters are also examined. A summary of the Lake Murray monitoring results for 2009 is presented below: Bed sediment results for arsenic concentrations in the finer <63µm size fraction showed a higher concentration of arsenic in the southern region of the lake, with a downward progression heading north. This trend has resulted from arsenicbearing fine particulates entering Lake Murray from the Strickland River during reverse flows in the Herbert River. In contrast to arsenic, bed sediment results for mercury concentrations for the <63µm fraction were at or below the detection limit. Bed sediment results for other trace metals in the <63µm fraction varied considerably although copper, lead, nickel, silver and zinc showed higher concentrations in the southern end of the lake similar to arsenic. Iron and selenium showed lower values in the south while chromium showed no distinct trend. Cadmium concentrations were all at or below the detection limit. Bed sediments in the total size fraction showed higher concentrations of arsenic, copper, lead, nickel and zinc in the southern end of the lake. Chromium and selenium showed lower values in the southern end while chromium showed no distinct trend. Cadmium, mercury and silver values were at or below their respective detection limits. For water quality in Lake Murray, the concentrations of all dissolved metals except iron and zinc were at or below their respective detection levels. Iron showed no distinct trend while zinc showed a slight decrease in concentrations from north to south. Similarly, total concentrations for all the relevant metals, except iron, nickel and zinc were at or below their respective detection limits. Total zinc concentrations showed an obvious decrease from north to south while downward trends for iron and nickel from north to south were slight. The analyses for sulphate showed a slight increasing trend from north to south. The ph values showed no distinct trend, with all median results being slightly acid. Chloride concentrations showed a slight decrease from north to south. PJV/ENV 1/10 6-1

224 2009 PJV Annual Environmental Report Lake Murray 6.1 Introduction PJV has maintained an extensive monitoring program on Lake Murray since the start of operations to verify that the practice of riverine disposal of tailings and waste rock is not having a detrimental effect on the Lake Murray ecosystem or the health of approximately 3,000 people who live near the lake. The Lake Murray people rely on the lake as an important source of fish. These people have naturally high levels of mercury bioaccumulated in their bodies through the food chain and there was concern prior to mining that mine-derived sediment could enter Lake Murray and exacerbate this problem. Lake Murray is an off-river water body in the Lower Strickland River region. The lake normally drains via the Herbert River into the Strickland River. However, flow reversals occur in the Herbert River approximately 15% of the time NSR, Lake Murray Mercury and Arsenic Loads, 1995 when the Strickland River rises after heavy rainfall in the mountains, and the water level of the Lower Strickland is higher than that of the lake. This situation allows sediment from the Strickland River, including some mine-derived material, to enter the southern region of the lake where deposition of the sediment can occur. The presence of mine-derived, metal-bearing sediment in Lake Murray necessitates PJV to regularly monitor the lake for the duration of the Porgera mine life. The metals of concern are arsenic and mercury, and much of PJV s monitoring activities at Lake Murray are centred around the origin, movement and fate of these trace metals. Measurements of trace metals within the lake were conducted on bed sediments, water and biota. The analyses of sediment and biota are the most important because they provide time-integrated concentrations that are generally much higher than in water. Results of these analyses are grouped into three categories according to location, i.e. into the southern, central and northern regions of the lake. Bed sediment and water samples were collected at a number of locations throughout the lake Figure 6-1. Metal concentrations in bed sediments and water are presented as box plots in Figures 6-2 to 6-7 for monitoring conducted during A brief description of how to interpret box plots is presented in Appendix 1 of this report. Other parameters including ph, sulphate and chlorides are presented in Figure 6-8. Results from 2003 to 2009 for bed sediments and water quality for the southern, central and northern regions of the lake are presented in Tables 6-1 and 6-2, respectively. The results of biota samples collected at Lake Murray during 2009 are presented separately in Section Methods Bed sediments were collected using a grab sampler made of stainless steel. The main objective in sampling was to collect as much of the sediment layer top 2cm as possible without losing the fines. No sieving was conducted on the samples. The samples were taken and packed into sealable plastic bags immediately after collection and stored in freezer boxes. Trace metal analyses were then conducted at the National Measurement Institute NMI laboratory in Sydney. The samples were analysed for trace metal concentrations in the minus 63 micron <63µm size fraction and for total PJV/ENV 1/10 6-2

225 2009 PJV Annual Environmental Report Lake Murray metals. The trace metals analysed included arsenic, cadmium, chromium, copper, iron, lead, mercury, nickel, silver and zinc. Lake Murray water samples were collected at the same locations as bed sediments. The samples were then sent to NMI and analysed for dissolved and total trace metals, and other parameters. Trace metals analysed included those mentioned in the previous paragraph. PJV/ENV 1/10 6-3

226 2009 PJV Annual Environmental Report Lake Murray Figure 6-1 Sediment and water quality sampling locations within Lake Murray Northern Region N30 N28 N26 N25 N6 N18 N10 N9 Central Region N21 N20 N1 S7 S6 S5 Southern Region X7 X6 X5 X4 X3 S4 S3 S2 X2 S1 X1 PJV/ENV 1/10 6-4

227 2009 PJV Annual Environmental Report Lake Murray 6.3 Results Bed Sediments Arsenic Bed sediment results for arsenic concentrations in the finer <63µm size fraction for 2009 are presented as a box plot diagram in Figure 6-2. The <63µm fraction was chosen because most metal-bearing sediments in Lake Murray are in the finer fraction. The results showed a higher concentration of arsenic-bearing sediments in the southern region of the lake, with a downward progression of concentrations heading north. This trend has resulted from arsenic-bearing fine particulates entering Lake Murray from the Strickland River during reverse flows of the Herbert River. Figure 6-2 Between site differences in arsenic concentrations of <63 µm sediment fractions in Lake Murray for PJV/ENV 1/10 6-5

228 2009 PJV Annual Environmental Report Lake Murray Mercury Bed sediment results for mercury concentrations for the finer <63µm size fraction are presented in Figure 6-3. In contrast to arsenic, mercury concentrations were very low and either at or below the detection limit. Figure 6-3 Between site differences in mercury concentrations of <63µm sediment fractions at Lake Murray for Other Metals Apart from arsenic and mercury, other trace metal concentrations in the <63 µm fraction of bed sediments for 2009 are shown in Figure 6-4. The results varied considerably although copper, lead, nickel, silver and zinc showed higher concentrations in the southern end of the lake similar to arsenic. Iron and selenium showed lower values in the south while chromium showed no distinct trend. Cadmium concentrations were all at or below the detection limit of 0.5 µg/g. Figure 6-5 shows total trace metal concentrations in bed sediments for Arsenic, copper, lead, nickel and zinc showed higher concentrations in the southern end of the lake. Chromium and selenium showed lower values in the southern end while chromium showed no distinct trend. Cadmium, mercury and silver values were at or below their respective detection limits. Mean annual bed sediment metal concentrations for the <63 µm and total fractions in the southern, central and northern regions of Lake Murray from 2004 to 2009 are presented in Table 6-1. PJV/ENV 1/10 6-6

229 2009 PJV Annual Environmental Report Lake Murray ""# % # &'# ##% # *%& Figure 6-4 Between site differences in metal concentrations of <63µm sediment fraction in Lake Murray for All metals are measured in mg/kg dry weight. PJV/ENV 1/10 6-7

230 2009 PJV Annual Environmental Report Lake Murray +,#%& ""# + % + # + -# &. + &'# + ##% + # + *%& Figure 6-5 Between site differences in total metal concentrations in sediments at Lake Murray for All metal concentrations are measured in mg/kg dry weight. PJV/ENV 1/10 6-8

231 2009 PJV Annual Environmental Report Lake Murray Table 6-1 Bed sediment mean concentrations in North, Central and South regions of Lake Murray All concentrations in ug/g. REGIONS NORTH CENTRAL SOUTH Year As As-T Cd Cd-T Cr Cr-T Cu Cu-T Fe Fe-T Pb Pb-T Hg Hg-T Ni Ni-T Se Se-T Ag Ag-T Zn Zn-T = <63 µm fraction T= total fraction PJV/ENV 1/10 6-9

232 2009 PJV Annual Environmental Report Lake Murray Water Quality Concentrations of dissolved metals in Lake Murray water for 2009 are presented as box plots in Figure 6-6 for all the relevant metals. The concentrations of all metals except iron and zinc were at or below their respective detection levels. Iron showed no distinct trend while zinc showed a slight decrease in concentrations from north to south. Similar to above, total concentrations for all the relevant metals, except iron, nickel and zinc were at or below their respective detection limits Figure 6-7. Total zinc concentrations showed an obvious downward trend from north to south while downward trends for iron and nickel from north to south were slight. Annual mean concentrations from 2003 to 2009 for dissolved and total metals and other water quality parameters for the southern, central and northern regions of the lake are presented in tabular form in Table 6-2. All these results were very low and no specific trends can be seen. The analyses for sulphate showed a slight increasing trend from north to south. The ph values showed no distinct trend, with all median results being slightly acid. Chloride concentrations showed a slight downward trend from north to south Figure 6-8. PJV/ENV 1/

233 2009 PJV Annual Environmental Report Lake Murray /,,#,#%& /,,#& /,,#& /,,#&""# /,,# % /,,## /,,## &. /,,#%&'# /,,#,# /,,#0%& Figure 6-6 Between site differences in dissolved metal concentrations for water samples in Lake Murray for PJV/ENV 1/

234 2009 PJV Annual Environmental Report Lake Murray 1,#%& 1& 1& 1&""# 1 % 1# 1# &. 1%&'# 1,# 10%& Figure 6-7 Between site differences in total metal concentrations for water samples in Lake Murray for 2009 PJV/ENV 1/

235 2009 PJV Annual Environmental Report Lake Murray /,,#,"1# /,,#& # " Figure 6-8 Between site differences in ph, sulphate and chloride of water samples in Lake Murray for 2009 PJV/ENV 1/

236 2009 PJV Annual Environmental Report Lake Murray Table 6-2 Water quality mean values in North, Central and South Regions of Lake Murray All metal concentrations in ug/l. REGIONS YEAR As-D As-T Cd-D Cd-T Cr-D Cr-T Cu-D Cu-T Fe-D Fe-T Pb-D Pb-T Hg-D Hg-T Ni-D Ni-T Ag-D Ag-T Zn-D Zn-T NORTH CENTRAL SOUTH D= Dissolved T= Total PJV/ENV 1/

237 2009 PJV Annual Environmental Report Lake Murray Table 6-2 cont. Water quality mean values in North, Central and South Regions of Lake Murray All metal concentrations in ug/l. REGIONS NORTH CENTRAL SOUTH YEAR ph Cond TSS Ca-D Mg-D Na-D K-D Cl-D SO 4-D units µs/cm mg/l mg/l mg/l mg/l mg/l mg/l mg/l D= Dissolved PJV/ENV 1/

238 2009 PJV Annual Environmental Report Biological Monitoring 7.0 Biological Monitoring Summary This report summarises the biological data collected between 1 January and 31 December The full report on biological monitoring is presented as Appendix 2 of this report. The aims of the biological programs are twofold. Firstly, they provide specimens for tissue trace metal analyses that are useful for biomonitoring and human metal intake studies via aquatic food consumption. Secondly, they generate data to assess changes in the species richness, abundance and condition state of health of fish, and some invertebrates, that may have resulted from mining activities. The sampling sites are divided into three sections: the Upper Catchment section Lagaip River at Wankipe and Wasiba, the Ok Om at Sisimin, and the Kuru and Pori Rivers; the Lowland Strickland section Strickland River at Bebelubi and Tiumsinawam, the Tomu River, Baia River and SG5; and the Lake Murray section at Maka, Pangoa and Miwa. 7.1 SPECIES RICHNESS, ABUNDANCE AND CONDITION In the upper catchment, there was no evidence to suggest any mine-related impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year 2009, nor in rank correlation assessments of trends over the extent of available data between 2000 and 2009 at each site except for at Wasiba where a declining trend was detected for prawn numbers and biomass from 2000 to Standardised sampling is not currently undertaken at the reference sites at Kuru River and Pori River due to the lack of suitable sandbanks to perform seine netting. It is planned that during 2010 backpack electrofishing will be implemented at all upper catchment sites to increase the likelihood of achieving sample numbers for tissue collection and to give another standardised method to measure species richness, abundance, diversity and biomass. At lower Strickland River sites standardised gill and seine netting did not suggest any minerelated impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year There were no unmatched decreasing trends detected at sites downstream of the mine within the time period 2000 to Hydroacoustic sampling at lower Strickland off river water bodies and Lake Murray was undertaken in In 2009, fish density at Avu was found to be significantly greater than that observed at Maka, although it is thought that this was partly an artefact of the large amount of floating macrophyte racks at Avu. For the oxbow lakes, Levame, Oxbow 3 and Zongamange, no significant differences in fish density were detected. A comparison of fish density between sampling in 2008 and 2009 at each site detected significant differences for Avu, Maka and Zongamange. At Avu and Zongamange, fish density was found to have significantly decreased in 2009 when compared with data from 2008 while at Maka fish density observed in 2009 was significantly greater than that seen in While differences have been detected, the use of hydroacoustic sampling is still in its early stages and further years of sampling will be needed for full understanding of the natural variation that would be expected to be seen at these sites. Specimen condition in the upper catchment indicated a significant difference for the prawn M. handschini at Wasiba when compared with prawns collected at Pori River, indicating a possible mine-related effect. This trend was not observed between Wasiba and the other reference sites at Ok Om or Kuru River but should be closely monitored throughout 2010 monitoring. Spearman s rank correlations indicated that there were no significant decreasing PJV/ENV-1/10 7-1

239 2009 PJV Annual Environmental Report Biological Monitoring trends for N. equinus or M. handschini at sites downstream of the mine within the time period 2000 to The condition of fish and prawns at lower Strickland River sites was not found to be significantly different between sites downstream of the mine and reference sites. However, a significant decreasing trend in the condition of P. macrorhynchus collected at Tiumsinawam was detected over the time period 2000 to TISSUE METAL CONCENTRATIONS Quality Assurance Laboratory based quality assurance was acceptable for samples analysed in Quarters 2, 3 and 4, while laboratory duplicate samples in Quarter 1 where outside the required RPD values for arsenic, nickel, copper, chromium and mercury. The use of field blanks was a great improvement over recent years and the biological team should be commended for this effort. A total of 31 field blanks were used in 2009, a major improvement on 2008 where only seven field blanks were used. The analysis of the field blanks indicated that some contamination of samples is occurring during sample processing and possibly during sample preparation at the analytical laboratory. A review of sample processing during 2010 is recommended. The results of the field blank analysis indicated that a greater margin of error should be associated with the samples analysed in 2010 and the subsequent tissue metals analysis Temporal and Spatial Variation Tissue sampling of target organisms was undertaken at all planned sites in 2009, except at Lake Murray where landowner intervention and unreasonable compensation demands prevented sampling for tissues from occurring. Sampling at sites in the Lower Strickland continued at the expanded number of sites which commenced in 2008 with both Bebelubi and the reference site at Baia River sampled for the fourth year in a row with plans to increase sampling at these sites from biannual to quarterly. The extent of mine-related and in some cases anomalous elevation of metal bioaccumulation is discussed for each metal in turn below: Cadmium: The prevalence of cadmium in tissues from prawns and fish from both the upper catchment and the lower Strickland River region has increased in All samples of prawn cephalothorax from all sites downstream of the mine were found to be significantly elevated compared with samples from all reference sites. Other tissue types that were found to contain significantly elevated concentrations of cadmium compared with all reference sites were prawn flesh at Wankipe, Wasiba and Tiumsinawam and fish liver at Bebelubi Figure 7-1. Tissue types where sites downstream of the mine were found to have significantly elevated average cadmium concentrations when compared with at least one of the reference sites was for prawn flesh at Tiumsinawam and fish liver at Wankipe and Wasiba. Increasing trends in cadmium concentrations at possible impact sites that were not matched at reference sites were also detected for a number of tissues, including fish liver at Tiumsinawam and Bebelubi over the longer term and Tiumsinawam over the shorter term and prawn flesh at Wasiba and Tiumsinawam over the shorter term. PJV/ENV-1/10 7-2

240 2009 PJV Annual Environmental Report Biological Monitoring Cd [mg/kg] a Wasiba Wankipe Ok Om Pori Kuru Cd [mg/kg] b Wasiba Wankipe Ok Om Pori Kuru Cd [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia Cd [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia c d Cd [mg/kg] Bebelubi Tiumsinawam Tomu Baia Cd [mg/kg] Bebelubi Tiumsinawam Tomu Baia e Figure 7-1 Average concentrations of cadmium observed for a M. handschini cephalothorax, b N. equinus liver, c M. rosenbergii cephalothorax, d M. rosenbergii flesh, e M. latidactylus cephalothorax, f P. macrorhynchus liver. f Copper: Average concentrations of copper were found to be significantly elevated in fish flesh at Tiumsinawam when compared with both reference sites while copper concentrations in prawn cephalothorax at Wasiba and Tiumsinawam were significantly higher than at least one of the reference sites and prawn flesh was found to have elevated levels of copper at Wankipe and Tiumsinawam compared with at least one reference site. Increasing trends in copper concentrations at potentially mine impacted sites that were not matched at corresponding reference sites were detected for fish flesh at Wasiba over the shorter term, at Bebelubi in prawn flesh over the longer term, at Tiumsinawam in prawn cephalothorax and fish liver over the longer term, at Bebelubi in fish flesh over the longer term and at Tiumsinawam in fish flesh over the shorter term. PJV/ENV-1/10 7-3

241 2009 PJV Annual Environmental Report Biological Monitoring Lead: Concentrations of lead were found to be significantly elevated in prawn cephalothorax at Wasiba and Wankipe when compared with all reference sites, at Wankipe in prawn flesh compared with all reference sites and fish liver at Bebelubi compared with all reference sites Figure 7-2. Possible impact sites that were found to have significantly elevated concentrations of lead compared with at least one of the reference sites was prawn cephalothorax collected from Tiumsinawam, SG5 and Bebelubi, prawn flesh at Tiumsinawam and fish liver at Wankipe and Wasiba. There were no significant increasing trends detected at potential impact sites for lead in all tissue types over both the short and long term data available. Pb [mg/kg] a Wasiba Wankipe Ok Om Pori Kuru Pb [mg/kg] b Wasiba Wankipe Ok Om Pori Kuru Pb [mg/kg] Bebelubi Tiumsinawam Tomu Baia c Figure 7-2 Average concentrations of lead for a M. handschini cephalothorax, b M. handschini flesh, c P. macrorhynchus liver. Zinc: Average concentrations of zinc were found to be significantly elevated in prawn cephalothorax at SG5 compared with all reference sites and in fish liver at Bebelubi compared with all reference sites. Other potentially impacted sites that have been found to be elevated when compared with at least one of the reference sites were Tiumsinawam, SG5 and Bebelubi for prawn cephalothorax, Tiumsinawam for prawn flesh and Wankipe and Wasiba for fish liver. Increasing trends that were detected for zinc concentrations in tissues at potentially mine impacted sites that were not matched at reference sites included prawn flesh at Wasiba over the longer term, fish flesh at Wankipe over both the longer and shorter term and in prawn cephalothorax, fish flesh and fish liver at Tiumsinawam over the longer term PJV/ENV-1/10 7-4

242 2009 PJV Annual Environmental Report Biological Monitoring Selenium: Selenium concentrations that were found to be significantly elevated at potentially impacted sites compared with all reference sites included prawn flesh at Tiumsinawam, fish liver at Bebelubi and fish flesh at Wasiba and Bebelubi. Other sites that were found to have significantly elevated concentrations of selenium compared with at least one of the reference sites included Wasiba, Wankipe and SG5 for prawn flesh, Wasiba for fish liver and Wankipe for fish flesh. Increasing trends that were detected at sites downstream of the mine that weren t matched at reference sites included fish flesh at Wankipe, Tiumsinawam and Bebelubi over the longer term, prawn flesh at Tiumsinawam and SG5 over the shorter term, prawn cephalothorax at Tiumsinawam and Bebelubi over the longer term and at Tiumsinawam for fish liver over the longer term. Selenium was found to be increasing for a number of tissue types at both reference and impact sites in the upper catchment and the lower Strickland River region. Arsenic: Average concentrations of arsenic were found to be significantly elevated in prawn cephalothorax at Wasiba, Wankipe and SG5 and prawn flesh at SG5 compared with all reference sites Figure 3. Significant increasing trends at sites downstream of the mine that were not matched by reference sites were observed at Wasiba for prawn cephalothorax and flesh over the long term, at SG5 for prawn cephalothorax over the shorter term and at Tiumsinawam and Bebelubi for fish liver over the longer term As [mg/kg] a Wasiba Wankipe Ok Om Pori Kuru As [mg/kg] Bebelubi Tiumsinawam SG5 Tomu b Figure 7-3 Average concentrations of arsenic for a M. handschini cephalothorax, b M. rosenbergii flesh, c P. macrorhynchus liver. Baia Mercury: Nickel: Average concentrations of mercury were found to be elevated at the impacted site Bebelubi for both fish liver and flesh when compared with all reference sites. Significant increasing trends for mercury concentrations at impacted sites that were not matched at reference sites included prawn cephalothorax at Wasiba over the short term, prawn cephalothorax at Tiumsinawam over the longer term and fish flesh at Bebelubi over the longer term. Concentrations of nickel that were observed to be significantly elevated at impact sites compared with at least one reference sites included Tiumsinawam and SG5 for prawn cephalothorax samples. Significant increasing trends observed at impacted sites that were not matched at reference sites occurred at Tiumsinawam for prawn cephalothorax over the longer term and at Tiumsinawam for prawn flesh over the shorter term. The results of tissue metals analysis for samples collected in 2009 indicated that the patterns of elevation of metal bioaccumulation in the Lagaip River and the lower Strickland River region reported in previous editions of the Annual Biology Report has persisted. PJV/ENV-1/10 7-5

243 2009 PJV Annual Environmental Report Biological Monitoring Significantly elevated levels of cadmium and lead have continued to be detected in prawn cephalothorax right down to SG5. For cadmium this pattern has remained in samples. Overall, these results demonstrated the persistence of the patterns of elevation and of metal bioaccumulation in the Lagaip River that had been reported previously and that the elevation of bioaccumulation of cadmium has continued to be widespread in the lower Strickland. Elevated bioavailability of arsenic was observed as far down the river system as SG5 in both prawn cephalothorax and flesh samples, while for mercury this was observed in both fish flesh and liver only at Bebelubi in the lower Strickland. While an increase in the prevalence of some metals and metalloids throughout the catchment can be inferred from the tissue metal concentration results, the contamination that was detected in the field blank samples needs to be taken into consideration. Concentrations of copper, zinc, selenium and mercury were found to be outside the acceptable quality assurance limits of the field blanks from each quarter. Therefore, the interpretation of the results needs to make allowance for this increased margin of error. Taking this into account the results of the tissue metals analysis were very similar to the results from 2007 and The results of the tissue metal concentrations for each tissue type and organism type were screened against the lowest observed concentration co-occurring with an effect LOEC from the effects database of Jarvinen and Ankley The ratio of results above:below the corresponding effects threshold for impact sites was found to be greater than for any of the corresponding reference sites at all impacted sites down to Tiumsinawam for cadmium in prawn cephalothorax and fish liver and also for mercury in fish liver and zinc in fish flesh. The use of literature LOEC values as a screening tool for the risk of adverse biological consequences of the observed patterns of metal bioaccumulation suggests that it was not possible to conclude that there was little risk of adverse consequences at least, as far downstream as the Strickland River at Tiumsinawam. However, this approach is at best an initial screen of potential risk and cannot be used to conclude that there is increased risk. A dedicated effort to collect prawns from the upper catchment for serum sorbitol dehydrogenase enzyme marker analysis was undertaken in the 3 rd quarter of Samples were collected from the impacted sites in the Lagaip River at Wasiba and Wankipe and at the reference sites at Ok Om and Pori River. The results of the analysis on the prawn abdomen indicated significantly p=0.001 elevated hepatic cell damage in prawns collected from Wasiba and Wankipe when compared with prawns from the reference sites. This result is similar to that detected in 2006 where prawns from the impacted sites at Wasiba and Wankipe where observed to have increased levels of SDH compared with reference sites. It is not known whether the amount of hepatic cell damage reflected by these increased levels of SDH are tolerable by the prawn species sampled. Investigations into the relationship between these levels of SDH in the prawn abdomen and organism health would allow for a better understanding of the state of the population in the upper catchment. PJV/ENV-1/10 7-6

244 2009 PJV Annual Environmental Report Biological Monitoring 400 SDH Activity mu/g tissue Pori Ok Om Wasiba Wankipe Site Figure 7-4 Results of SDH analysis of prawns collected from sites in the upper catchment in 2009 During 2010, the continuation of the SDH program in the upper catchment and the inclusion of sites in the lower Strickland region will further enhance the biomonitoring programs power to detect impacts at the population level before detrimental damage at the population level occurs. During 2009, a PhD project commenced with the aim to investigate the mechanisms for elevation of bioavailability of metals in the lower Strickland region. The project, run in partnership with CSIRO and Hydrobiology, will attempt to form an understanding of the nature of the bioavailable fractions, and whether or not this can be managed. 7.3 REFERENCES Jarvinen A.W. and Ankley G.T Linkage of Effects to Tissue Residues: Development of a Comprehensive Database for Aquatic Organisms Exposed to Inorganic and Organic Chemicals. SETAC Press, Pensacola. PJV/ENV-1/10 7-7

245 2009 PJV Annual Environmental Report Rehabilitation & Closure 8.0 REHABILITATION & CLOSURE SUMMARY The total area disturbed by PJV operations at the end of 2009 was 1,444 hectares PJV Mine Dept. The increase since December 2006 was mainly due to the expansion of the waste rock dumps. The main focus of work in 2009 was continued revegetation of the Kogai stable dump. To date, 85% of the Kogai has been stabilised with ground cover establishment, with the remaining 15% used for operational purposes such as haul roads and stockpiles. Additional works conducted during 2009 are summarised as follows: A total of 15,358 tree seedlings, supplied by both contractors and raised from the environment nursery, was planted on the Kogai stable dump. Most were planted as replacements for dead trees, those uprooted by illegal miners and those that were suppressed by Desmodium grass Erosion controls such as erosion bunds and silt traps were constructed on Kogai and Anawe stable dumps while those constructed previously were desilted. The total competent waste rock in 2009 was approximately 12.3 M tonnes. Some competent waste rock was used for roads, sheeting and buttressing, with the remainder being placed at either the Kogai K80 or Anawe North stable dumps. Incompetent erodible waste rock to the two erodible dumps totalled 14.5 M tonnes with the Anawe receiving more than 8.7 M tonnes in The erosion trial showed that rip rock slope battering and contouring grass seed mix at 1 metre interval had the highest erosion rates over the four months. The best method of minimizing erosion on the slope was hand broadcasting grass seed mix with fertiliser DAP at 600 kg/ha. Various shallow-rooted food crops, including sweet potato, cabbage, broccoli and beans were tested under different mine soil types for metal absorption. The results showed much variation and will be replicated again before reporting the findings in next year s 2010 report. PJV/ENV 1/10 8-1

246 2009 PJV Annual Environmental Report Rehabilitation & Closure 8.1 Introduction The rehabilitation and closure work programs are governed by three environment permit conditions under rehabilitation. Condition 12. The permit holder shall undertake progressive landform rehabilitation during the operational phase, including soil conservation and rehabilitation of disperse soil, stockpiles, quarry extraction sites, etc. Condition 13. The permit holder shall undertake progressive vegetation regeneration work on construction sites including access road, stockpiles, quarry extraction sites, underground and process facilities sites etc. Condition 14. The permit holder shall submit a detailed Mine Rehabilitation Program to the Director five 5 years prior to the official closure date of the mining activity. 8.2 Progressive Rehabilitation Disturbed Areas The total surface mine footprint at the end of 2009 was 1444 hectares, up from 1,393 ha in 2008 Table 8-1. These values were obtained from PJV Mine Dept and based on satellite imagery. A total of 46 ha Figure 8-2 was reclaimed through mine operation on K71 semi-competent dump. Table 8-1 Disturbed areas in hectares Year Previously disturbed and unreclaimed New disturbed and unreclaimed Previously Reclaimed New reclaimed Reclaimed and released Total ha PJV/ENV 1/10 8-2

247 2009 PJV Annual Environmental Report Rehabilitation & Closure Figure 8-1 K80 Dump surface area extension Figure 8-2 K71 semi-competent dump reclaimed by mine operations PJV/ENV 1/10 8-3

248 2009 PJV Annual Environmental Report Rehabilitation & Closure Erosion Controls In 2009, several soil erosion bunds and silt traps were constructed to minimise and control soil washed from the dump slopes and benches. Several erosion bunds were constructed at the base of Anawe North stable dump to control and minimise soil particles washed into the drains below A10 dump toe entering the Pongema River. Silt traps were cleaned out on Kogai stable dump and a new erosion bund constructed below the Kogai landfill dump to control excess waste and runoff from the landfill dump entering the main drains Plates 8-1 to 8-4. Plate 8-1 Erosion bund on Anawe North dump Plate 8-2 Erosion bund below K71 rubbish dump Plate 8-3 Silt traps on Kogai stable dump Plate 8-4 Erosion bund below A Progressive Revegetation In 2009, 29,245 new trees and Saranga species were planted covering an area of ha. Reforesting was confined to areas within the new security fence line, primarily to avoid illegal trespassers from uprooting and chopping trees. The primary objective for the rehabilitation of Kogai stable dump is to develop a forest ecosystem that resembles the natural adjacent forest. Therefore, the main focus has been on planting mainly local tree species as well as other locally preferred plants on Kogai dump K62 and K65. An introduced tree species planted was Eucalyptus pelita and a total of 1,450 E. pelita seedlings were planted among the native species. The native species included were Nothofagus, Lithocarpus, Castanopsis, Prunus, Syzyguim, Garcenia, Podocarpus and Drydicidulum nidylidum, Dodonea viscosae and Dysoxylum, totaling 4,950 seedlings. Each tree was planted at a spacing of 2m x 3m, covering 3.84 ha. A total of 23,845 Pandanus Saranga suckers purchased from local suppliers were planted among the tree seedlings. Each sucker was planted at a spacing of 2m x 2m. The Pandanus planted on K65, K62 and K58 covered 9.53 ha Plate 8-5. Other minor tree and shrub species such as ferns, piper, vines and non-woody plants were uprooted from the Kogai forest K80 and planted directly on K62, K65 and K58 rehabilitation sites. PJV/ENV 1/10 8-4

249 2009 PJV Annual Environmental Report Rehabilitation & Closure The Pandanus plant Saranga species is a highly valued non-woody plant in the Porgera area and other high altitude areas in the Highlands of PNG. This plant has many uses including edible high protein nuts for food human and pig, leaves for house roofing and mat weaving, and trunk for house walls and flooring. Various local groups were engaged to collect Pandanus suckers from their respective forests. A total of 23,845 suckers collected were purchased and planted on the Kogai stable dump. Plate 8-5 Young Pandanas tree on K62 rehabilitation area Grass seeding was minimal in 2009 as no new areas were available. A total of 0.22 ha along the new fence line was seeded with 220 kg of environmental seed mix together with DAP-fertilizer in the last quarter of Nursery Production There were no seedlings produced from the Yoko nursery in 2009 as it was undergoing maintenance from a slump around the nursery beds. Most of the nursery activity was from Alipis 3 or the core shed nursery. Also, more than 15,000 polybags were packed with soil for raising native and exotic tree seedlings. Local contractors were engaged to do the soil sieving and packing. A total of 4,500 undergrowth seedlings wildings were collected from Kumbi forest and raised in the polybags while the rest were from seeds germinated in the nursery. The seedling production in the year totaled 15,358. The different tree species raised and the total produced are given in Table 8-2. PJV/ENV 1/10 8-5

250 2009 PJV Annual Environmental Report Rehabilitation & Closure Table 8-2 Number of seedlings produced for each species. Seedling Production Tree Species Total produced Nothofagus spp 950 Syzygium spp 270 Castanopsis acuminatissima 102 Dodonea viscosae 5435 Lithocarpus 344 Harpullia arborea 146 Prunus schlechteri 40 Dysoxylum gaudichaudianum 182 Caladcluvia 70 Sloanea sogerensis 160 Myristica spp 14 Acaccia mangium 566 Eucalyptus peliata 2579 Wildings 4500 Total 15,358 Seedlings were supplied by local suppliers, identified and supervised by PJV officers. These locally raised seedlings supplement planting shortfalls with nursery grown seedlings. Mature and well-raised seedlings were selected and brought on to site for planting. Each hardwood species was priced at K1.50 and the soft wood species at K1.00 each. The difference in price was to encourage an increase in the supply of hardwood species to meet the planting target of the hardwoods on the Kogai stable dump Wood Chip Production A 12 horsepower shredder was bought early in This shredder was taken to the adjacent forest at Kogai to produce chips during the second and third quarter. Chips were produced from twinges, branches and medium size timbers Plate 8-6. An estimated 5 tonnes of chips were produced and stored at the Alipis 3 nursery yard. The wood chips will be used on the dump slopes and benches as organic cover material to protect the soil from erosion. The wood chips will also encourage volunteer seedlings, when mixed with soil for tree-seedling raised in the nursery and applied with seeds on the dumps, to create a suitable growth medium for plant establishment Plate 8-7. Plate 8-6 Producing wood chips Plate 8-7 Mixing soil with wood chips PJV/ENV 1/10 8-6

251 2009 PJV Annual Environmental Report Rehabilitation & Closure 8.3 Waste Rock Monitoring Waste Rock Tonnages to Dumps A total of 5.4 and 6.8 million tonnes of competent waste rock was placed on Anawe North stable dump and Kogai stable dump, respectively. Anawe erodible dump received 8.7 million tonnes in 2009 while Anjolek erodible dump received 5.8 million tonnes Table 8-3. Table 8-3 Waste rock dumped between 2004 and 2009 tonnes Year Qtr Anawe Erodible Anawe Stable Anjolek Erodible Kogai Stable Q1 6,896,320 4,836, , Q2 8,707,620 4,656,440 3,460 60,060 Q3 6,819,045 4,526, , ,280 Q4 3,600,165 2,974,125 2,135, ,820 Q1 5,494,220 2,478, , , Q2 5,646,933 1,892,720 1,093,520 32,480 Q3 2,758, ,440 5,331,980 4,820 Q4 3,537, ,040 4,930,120 62,440 Q1 1,800, ,020 3,491, , Q2 2,052, ,060 4,962, ,950 Q3 1,120,365 59,530 3,923, ,840 Q4 1,334, ,426,370 1,282,695 Q1 1,055,980 1,398,760 3,324,305 1,099, Q2 1,018,110 1,594,340 3,568, ,720 Q3 1,071,615 1,341,305 5,079,455 1,503,410 Q4 4,033,650 3,594,600 1,222, ,575 Q1 3,614,560 3,835,765 2,180, , Q2 2,498,850 3,728,945 2,133,360 28,130 Q3 1,466,655 3,886,635 1,656, ,020 Q4 2,483,030 2,757,510 1,607,185 1,306,865 Q1 2,811,960 1,631,545 1,451,865 2,555, Q2 1,946,115 1,090,370 2,292, ,440 Q3 2,255, ,440 1,491,740 1,395,240 Q4 1,651,845 1,774, ,905 1,940,130 PJV/ENV 1/10 8-7

252 2009 PJV Annual Environmental Report Rehabilitation & Closure 8.4 Trials and Research Erosion Trial Erosion models have received little attention internationally due to their low practicality, high cost and varying topography. Consequently, many governments, institutions, industries and farmers have resorted to easier methods to measure hill-slope erosion within reasonable time and cost. The method used at Porgera to measure slope erosion was adapted from Dissmeyer 1982 and Robichaud 2002 using the Silt Fence technique to measure soil erosion rates on the Kogai stable dump under various forms of slope cover. The project aim was to: Adapt and evaluate the Silt Fence technique for Porgera land rehabilitation Measure the effectiveness of soil erosion on revegetated sites and non-revegetated areas Measure monthly soil erosion from various forms of slope cover Assess the effectiveness of mulching on slopes using shredded mulch to reduce erosion. Stakes Treatment Area 1 m 5 m m Catchment Area Geofabric Figure 8-3 Erosion trial plot design The erosion trial was established on K62 slope by removing all vegetation and tilling the soil before erosion methods were trialled. The plots were lined up from east to west and faced north on a 35 degree slope. The main slope cover was comprised mainly of brown weathered mudstone. The contributing area was 50 sq metres. A 2 metre barrier between each treatment was set in place to control water flow and silt from outside the trial area. The catchment area was 5m x 0.3m x 0.4m or 0.6 sq metres. The geofabric silt mat was faced uphill to collect silt Plates 8-8 and 8-9. Periodic cleanout of the silt fences was carried out to obtain reliable measurements of the erosion rate. Cleaning the silt fences after each rainfall period improved the predictions on erosion. Care was taken to avoid tearing the fabric Plate PJV/ENV 1/10 8-8

253 2009 PJV Annual Environmental Report Rehabilitation & Closure Direct measurement of the total weight of the sediment collected was seen to be the most accurate way of assessing the erosion rate. The sediment was weighed and recorded in the field using plastic bags. A hand trowel was used to scrape the deposited sediment into the container or plastic bags. Wet weight was measured in the field and the sub-sample dried in the oven at 105 C for 24 hours before carrying out particle size analysis. The dry weight was taken and gravimetric water content measured. The weather station about 200 m from the trial site provided all the meteorology data required. Plate 8-8 Trial plot with geofabric mat installed Plate 8-9 Silt catchment area Plate 8-10 Hand broad cast treatment Plate 8-11 Cleaning catchment area PJV/ENV 1/10 8-9

254 2009 PJV Annual Environmental Report Rehabilitation & Closure Erosion Trial Result The trial was observed over four months only, due to complete coverage of grass on areas broadcast, while other areas were slow to establish vegetation cover. The monthly erosion rates for August, September, October and July were kg, kg, kg and 5.40 kg, respectively. Mean total rainfall for the four months was 231 mm, while the total rainfall for the months was 225 mm, mm, 220 mm and mm in order of increasing erosion recorded. The highest rainfall recorded in July mm had significant impact on the treatment rip rock battering with 2.87 kg eroding from the slope. Rip rock surface was seen to increase the surface collection area for rainfall thus causing erosion and small gullies down the slope. In other months, rip rock battering, contouring and control zero treatment had poor erosion control and was considered a poor practice to use on large scale mining areas Figure 8-4. Methods with the best ground cover minimised erosion and had low erosion per square metre 50 m 2 while methods with poor ground cover had high erosion rates per square metre. Rip rock slope battering and contouring grass seed mix at 1 metre intervals had the highest erosion rates over the four months. The best method of minimizing erosion on the slope was hand broadcasting grass seed mix with fertiliser DAP at 600 kg/ha Plate Figure 8-4 Monthly erosion with various methods on K62 slope Testing food crops for metal uptake in mine soil types Various shallow-rooted food crops, including sweet potato, cabbage, broccoli and beans were tested under different mine soil types for metal absorption. The results showed much variation and will be replicated again before reporting the findings in next year s 2010 report. PJV/ENV 1/

255 2009 PJV Annual Environmental Report Rehabilitation & Closure " # % &&' Figure 8-5 Particle Size Distribution Particle sizes that were most susceptible to erosion were those retained on the 1.4 mm sieve size. High erosion rates were obtained by broadcasting on the slope, 1 m contouring and control with zero treatment. The trial demonstrated that it is important to have some form of groundcover over the mine disturbed areas quickly. The use of rip rock battering on slopes must be covered quickly to minimise soil erosion. The surface created by the rock increases the area for water to collect and run off, thus increasing erosion on the slope. References: Dissmeyer, G. E How to use fabric dams to compare erosion from forest practices. Forestry Rep. SA-FR 13. Atlanta, GA: U.S. Department of Agriculture, Forest Service, Southeast areas. 11p. Nearing, Mark A.; Gover, Gerard; Norton,L.Darell Variability in soil erosion data from replicated plots. Soil science society of America Journal. 63: Robichaud, P.R; McCool, D.K.; Pannkuk,C. D.; Brown, R. E.; Mutch, P. W Trap efficiency of silt fences used in hillslope erosion studies. In: Ascough, J. C.,II; Flannagan, D.C., eds. Soil erosion research for the 21 st century, proceedings; 2001; Honululu, HI. St. Joseph, MI: American Society of Agricultural Engineers: PJV/ENV 1/

256 2009 PJV Annual Environmental Report Appendix 1 APPENDIX 1 Interpretation of Box Plots Box Plots In a box plot, the centre horizontal line within the box marks the median value of the sample. The length of the box shows the range within which the central 50% of the values fall, with the box edges called hinges at the first and third quartiles Q1 and Q3. To describe the information contained in a box plot, a few terms must first be defined. H-spread is the inter-quartile range or mid-range Q3-Q1. Fences define outside and far outside values and are defined as follows: Lower inner fence = Q1-1.5 x H-spread Upper inner fence = Q x H-spread Lower outer fence = Q1-3 x H-spread Upper outer fence = Q3 + 3 x H-spread ο Extreme Outlier Mild Outlier Third Quartile Q3 First Quartile Q1 Median Value The whiskers show the range of observed values that fall within the inner fences. In other words, they show the range of values that fall within 1.5 H-spreads of the hinges. Because the whiskers extend to observed values and the fences need not correspond to observed values, the whiskers do not necessarily extend all the way to the inner fences. Values between the inner and outer fences mild outliers are plotted with asterisks. Values beyond the outer fences, called extreme outliers, are plotted with empty circles. PJV/ENV 1/10 A1-1

257 APPENDIX 2 BIOLOGICAL MONITORING TECHNICAL REPORT 1 JANUARY 31 DECEMBER 2009 A2-1

258 PORGERA Joint Venture BIOLOGICAL MONITORING TECHNICAL REPORT 2009 Prepared by: PJV Biology with assistance from Hydrobiology Date: June 2010 Report No: PJV/ENV 1/10

259 EXECUTIVE SUMMARY This report summarises the biological data collected between 1st January and 31st December The aims of the biological programs are twofold. Firstly, they provide specimens for tissue trace metal analyses that are useful for bio-monitoring and human metal intake studies via aquatic food consumption. Secondly, they generate data to assess changes in the species richness, abundance and condition state of health of fish, and some invertebrates, that may have resulted from mining activities. The sampling sites are divided into three sections: the Upper Catchment section Lagaip River at Wankipe and Wasiba, the Ok Om at Sisimin, and the Kuru and Pori Rivers; Lowland Strickland section Strickland River at Bebelubi and Tiumsinawam, the Tomu River, Baia River and SG5, and Lake Murray at Maka, Pangoa and Miwa. SPECIES RICHNESS, ABUNDANCE AND CONDITION In the upper catchment, there was no evidence to suggest any mine-related impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year 2009, nor in rank correlation assessments of trends over the extent of available data between 2000 and 2009 at each site except for at Wasiba where a declining trend was detected for prawn numbers and biomass from 2000 to Standardised sampling is not currently undertaken at the reference sites at Kuru River and Pori River due to the lack of suitable sandbank to perform seine netting. It is planned that during 2010 backpack electrofishing will be implemented at all upper catchment sites to increase the likelihood of achieving sample numbers for tissue collection and to give another standardised method to measure species richness, abundance, diversity and biomass. At lower Strickland River sites standardised gill and seine netting did not suggest any mine-related impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year There were no unmatched decreasing trends detected at sites downstream of the mine within the time period 2000 to Hydroacoustic sampling at lower Strickland off river water bodies and Lake Murray was undertaken in In 2009, fish density at Avu was found to be significantly greater than that observed at Maka, although it is thought that this was partly an artefact of the large amount of floating macrophyte racks at Avu. For the oxbow lakes, Levame, Oxbow 3 and Zongamange, no significant differences in fish density were detected. A comparison of fish density between sampling in 2008 and 2009 at each site detected significant differences for Avu, Maka and Zongamange. At Avu and Zongamange, fish density was found to have significantly decreased in 2009 when compared with data from 2008 while at Maka fish density observed in 2009 was significantly greater than that seen in While differences have been detected, the use of hydroacoustic sampling is still in its early stages and further years of sampling will be needed for full understanding of the natural variation that would be expected to be seen at these sites. Specimen condition in the upper catchment indicated a significant difference for the prawn M. handschini at Wasiba when compared with prawns collected at Pori River, indicating a possible mine-related effect. This trend was not observed between Wasiba and the other reference sites at Ok Om or Kuru River but should be closely monitored throughout 2010 monitoring. Spearman s rank correlations indicated that there were no significant decreasing trends for N. equinus or M. handschini at sites downstream of the mine within the time period 2000 to 2009.

260 The condition of fish and prawns at lower Strickland River sites was not found to be significantly different between sites downstream of the mine and reference sites. However, a significant decreasing trend in the condition of P. macrorhynchus collected at Tiumsinawam was detected over the time period 2000 to TISSUE METAL CONCENTRATIONS Quality Assurance Laboratory based quality assurance was acceptable for samples analysed in Quarters 2, 3 and 4, while laboratory duplicate samples in Quarter 1 where outside the required RPD values for arsenic, nickel, copper, chromium and mercury. The use of field blanks was a great improvement over recent years and the biological team should be commended for this effort. A total of 31 field blanks were used in 2009, a major improvement on 2008 where only seven field blanks were used. The analysis of the field blanks indicated that some contamination of samples is occurring during sample processing and possibly during sample preparation at the analytical laboratory. A review of sample processing during 2010 is recommended. The results of the field blank analysis indicated that a greater margin of error should be associated with the samples analysed in 2010 and the subsequent tissue metals analysis. Temporal and Spatial Variation Tissue sampling of target organisms was undertaken at all planned sites in 2009, except at Lake Murray where landowner intervention and unreasonable compensation demands prevented sampling for tissues from occurring. Sampling at sites in the Lower Strickland continued at the expanded number of sites in 2008 with both Bebelubi and the reference site at Baia River sampled for the fourth year in a row with plans to increase sampling at these sites from biannual to quarterly. The extent of mine-related and in some cases anomalous elevation of metal bioaccumulation is discussed for each metal in turn below: Cadmium: The prevalence of cadmium in tissues from prawns and fish from both the upper catchment and the lower Strickland River region has increased in All samples of prawn cephalothorax from all sites downstream of the mine were found to be significantly elevated compared with samples from all reference sites. Other tissue types that were found to contain significantly elevated concentrations of cadmium compared with all reference sites were prawn flesh at Wankipe, Wasiba and Tiumsinawam and fish liver at Bebelubi. Tissue types where sites downstream of the mine were found to have significantly elevated average cadmium concentrations when compared with at least one of the reference sites included prawn flesh at Tiumsinawam and fish liver at Wankipe and Wasiba. Increasing trends in cadmium concentrations at possible impact sites that were not matched at reference sites were also detected for a number of tissues, including fish liver at Tiumsinawam and Bebelubi over the longer term and Tiumsinawam over the shorter term and prawn flesh at Wasiba and Tiumsinawam over the shorter term. Copper: Average concentrations of copper were found to be significantly elevated in fish flesh at Tiumsinawam when compared with both reference sites while copper concentrations in prawn cephalothorax at Wasiba and Tiumsinawam were significantly higher than at least one of the reference sites and prawn flesh was found to have elevated levels of copper at Wankipe and Tiumsinawam compared with at least one reference site.

261 Increasing trends in copper concentrations at potentially mine impacted sites that were not matched at corresponding reference sites were detected for fish flesh at Wasiba over the shorter term, at Bebelubi in prawn flesh over the longer term, at Tiumsinawam in prawn cephalothorax and fish liver over the longer term, at Bebelubi in fish flesh over the longer term and at Tiumsinawam in fish flesh over the shorter term. Lead: Zinc: Concentrations of lead were found to be significantly elevated in prawn cephalothorax at Wasiba and Wankipe when compared with all reference sites, at Wankipe in prawn flesh compared with all reference sites and fish liver at Bebelubi compared with all reference sites. Possible impact sites that were found to have significantly elevated concentrations of lead compared with at least one of the reference sites included prawn cephalothorax collected from Tiumsinawam, SG5 and Bebelubi, prawn flesh at Tiumsinawam and fish liver at Wankipe and Wasiba. There were no significant increasing trends detected at potential impact sites for lead in all tissue types over both the short and long term data available. Average concentrations of zinc were found to be significantly elevated in prawn cephalothorax at SG5 compared with all reference sites and in fish liver at Bebelubi compared with all reference sites. Other potentially impacted sites that have been found to be elevated when compared with at least one of the reference sites were Tiumsinawam, SG5 and Bebelubi for prawn cephalothorax, Tiumsinawam for prawn flesh and Wankipe and Wasiba for fish liver. Increasing trends that were detected for zinc concentrations in tissues at potentially mine impacted sites that were not matched at reference sites included prawn flesh at Wasiba over the longer term, fish flesh at Wankipe over both the longer and shorter term and in prawn cephalothorax, fish flesh and fish liver at Tiumsinawam over the longer term Selenium: Selenium concentrations that were found to be significantly elevated at potentially impacted sites compared with all reference sites included prawn flesh at Tiumsinawam, fish liver at Bebelubi and fish flesh at Wasiba and Bebelubi. Other sites that were found to have significantly elevated concentrations of selenium compared with at least one of the reference sites included Wasiba, Wankipe and SG5 for prawn flesh, Wasiba for fish liver and Wankipe for fish flesh. Increasing trends that were detected at sites downstream of the mine that weren t matched at reference sites included fish flesh at Wankipe, Tiumsinawam and Bebelubi over the longer term, prawn flesh at Tiumsinawam and SG5 over the shorter term, prawn cephalothorax at Tiumsinawam and Bebelubi over the longer term and at Tiumsinawam for fish liver over the longer term. Selenium was found to be increasing for a number of tissue types at both reference and impact sites in the upper catchment and the lower Strickland River region Arsenic: Average concentrations of arsenic were found to be significantly elevated in prawn cephalothorax at Wasiba, Wankipe and SG5 and prawn flesh at SG5 compared with all reference sites. Significant increasing trends at sites downstream of the mine that were not matched by reference sites were observed at Wasiba for prawn cephalothorax and flesh over the long term, at SG5 for prawn cephalothorax over the shorter term and at Tiumsinawam and Bebelubi for fish liver over the longer term.

262 Mercury: Nickel: Average concentrations of mercury were found to be elevated at the impacted site Bebelubi for both fish liver and flesh when compared with all reference sites. Significant increasing trends for mercury concentrations at impacted sites that were not matched at reference sites included prawn cephalothorax at Wasiba over the short term, prawn cephalothorax at Tiumsinawam over the longer term and fish flesh at Bebelubi over the longer term. Concentrations of nickel that were observed to be significantly elevated at impact sites compared with at least one reference sites included Tiumsinawam and SG5 for prawn cephalothorax samples. Significant increasing trends observed at impacted sites that were not matched at reference sites occurred at Tiumsinawam for prawn cephalothorax over the longer term and at Tiumsinawam for prawn flesh over the shorter term. The results of tissue metals analysis for samples collected in 2009 indicated that the patterns of elevation of metal bioaccumulation in the Lagaip River and the lower Strickland River region reported in previous editions of the Annual Biology Report has persisted. Significantly elevated levels of cadmium and lead have continued to be detected in prawn cephalothorax right down to SG5. For cadmium this pattern has remained in samples. Overall, these results demonstrated the persistence of the patterns of elevation and of metal bioaccumulation in the Lagaip River that had been reported previously and that the elevation of bioaccumulation of cadmium has continued to be widespread in the lower Strickland. Elevated bioavailability of arsenic was observed as far down the river system as SG5 in both prawn cephalothorax and flesh samples, while for mercury this was observed in both fish flesh and liver only at Bebelubi in the lower Strickland. While an increase in the prevalence of some metals and metalloids throughout the catchment can be inferred from the tissue metal concentration results, the contamination that was detected in the field blank samples needs to be taken into consideration. Concentrations of copper, zinc, selenium and mercury were found to be outside the acceptable quality assurance limits of the field blanks from each quarter. Therefore, the interpretation of the results needs to make allowance for this increased margin of error. Taking this into account the results of the tissue metals analysis were very similar to the results from 2007 and The results of the tissue metal concentrations for each tissue type and organism type were screened against the lowest observed concentration co-occurring with an effect LOEC from the effects database of Jarvinen and Ankley Sites where the ratio of results above:below the corresponding effects threshold for impact sites was found to be greater than for any of the corresponding reference sites where found at all impacted sites down to Tiumsinawam for cadmium in prawn cephalothorax and fish liver and also for mercury in fish liver and zinc in fish flesh. The use of literature LOEC values as a screening tool for the risk of adverse biological consequences of the observed patterns of metal bioaccumulation suggests that it was not possible to conclude that there was little risk of adverse consequences at least, as far downstream as the Strickland River at Tiumsinawam. However, this approach is at best an initial screen of potential risk and cannot be used to conclude that there is increased risk. A dedicated effort to collect prawns from the upper catchment for serum sorbitol dehydrogenase enzyme marker analysis was undertaken in the 3 rd quarter of Samples were collected from the impacted sites in the Lagaip River at Wasiba and Wankipe and at the reference sites at Ok Om and Pori River. The results of the analysis on the prawn abdomen indicated significantly p=0.001 elevated hepatic cell damage in prawns collected from Wasiba and Wankipe when compared with prawns from the reference sites. This result is similar to that detected in 2006 where prawns

263 from the impacted sites at Wasiba and Wankipe where observed to have increased levels of SDH compared with reference sites. It is not known whether the amount of hepatic cell damage reflected by these increased levels of SDH are tolerable by the prawn species sampled. Investigations into the relationship between these levels of SDH in the prawn abdomen and organism health would allow for a better understanding of the state of the population in the upper catchment. During 2010 the continuation of the SDH program in the upper catchment and the inclusion of sites in the lower Strickland region will further enhance the biological biomonitoring programs power to detect impacts at the population level before detrimental damage at the population level occurs. During 2009 a PhD project commenced with the aim to investigate the mechanisms for elevation of bioavailability of metals in the lower Strickland region. The project, run in partnership with CSIRO and Hydrobiology, will attempt to form an understanding of the nature of the bioavailable fractions, and whether or not this can be managed. RECOMMENDATIONS Implement electrofishing sampling at upper catchment and lower Strickland region sites to enhance the current methods used to monitor catch and to ensure adequate prawn samples are collected for tissue and SDH analysis; Continue to investigate and negotiate with landowners in the Nomad and Rentoul River systems to establish one more reference site in the lower Strickland region; Continue to increase the use of field blank samples and ensure the cleanliness of the biology laboratory when processing samples to limit the chance of contamination; Continue SDH analysis of upper catchment prawns as well as expanding the program to include prawns from the lower Strickland region; Implement a program to benchmark the effect levels of the elevated bioavailability of metals to the prawns in the upper catchment in terms of the observed SDH and the impacts this may be having on the biological processes of the organisms; Consider other sub-organism and organisms level effect markers in areas where SDH analyses demonstrate increased hepatic cell loss rates. Such markers could include histopathological examination of selected tissues and markers of fecundity, such as the gonado-somatic index. Development of this approach could be done in collaboration with the existing research being conducted jointly with CSIRO and Hydrobiology; Implement seine netting at SG5 and trial fyke nets in an effort to increase prawn catches.

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268 1 INTRODUCTION This report summarises the Biological Sampling Programs BSP carried out by Porgera Joint Venture PJV from January 2009 to December 2009 along the Lagaip and Strickland River System and sites located at Lake Murray. The aims of the BSP are twofold. Firstly, they provide specimens for tissue trace metal analyses that are useful for bio-monitoring and human metal intake studies via aquatic food consumption. The trace metal biomonitoring is the largest component of the BSP in terms of both effort and budget. It aims to monitor any mine-related changes in the bioavailability of metals in the Strickland River system via analysis of metal concentrations in selected tissue types from selected species collected from sampling sites that are either downstream of the mine or in reference locations in each major section of the river system. Secondly, the BSP generate data to assess changes in the species richness, abundance and condition state of health of fish, and some invertebrates, that may have resulted from mining activities. The sampling sites are divided into three sections: the Upper Catchment section Lagaip River at Wankipe and Wasiba, the Ok Om at Sisimin, and the Kuru and Pori Rivers; Lowland Strickland section Strickland River at Bebelubi and Tiumsinawam, the Tomu River, and the Baia River, and Lake Murray at Maka, Pangoa and Miwa. Hydroacoustic sampling has been introduced to the BSP to replace the previously used gill net and purse seine net sampling for catchability of fishes in Lake Murray and to extend fish density monitoring to selected Strickland River floodplain water bodies. In May 2004, Hydrobiology with the aid of PJV undertook a pilot study to determine the applicability of hydroacoustics in Lake Murray and off river water body sites in the Lower Strickland River Smith and West 2004, PJV It was concluded from this study that Hydroacoustic sampling of sites in Lake Murray and the Lower Strickland was a useful tool for mapping fish densities and that the advantages of Hydroacoustic sampling outweighed any disadvantages when compared with gill and purse seine netting. These advantages being: It is non-destructive. No fish are actually collected, so there is no risk of sampling effort affecting the fish stocks being monitored. The sample volume is very large. This tends to reduce the variability of the density estimates, and provide greater statistical power. Behavioural information is gained that is difficult to obtain by more traditional sampling methods. In 2004 diurnal vertical migrations of fishes were observed using hydroacoustics sampling. Other behavioural information could be gained using hydroacoustics sampling as the location of fishes is recorded in three dimensions to high resolution. Fish densities can be mapped in three dimensions within timeframes not possible for net sampling of fishes. In practical terms for floodplain sampling, hydroacoustics sampling is not depth limited. Purse seining can only be carried out in water depths up to 6 m for the net that PJV uses. At greater depths fish will escape under the net where it does not reach the lake bed, making density estimates inaccurate. Hydroacoustic sampling was continued in 2009 in Strickland River off river water bodies but due to landowner intervention sampling was not completed in Lake Murray.

269 2 METHODS 2.1 Abundance Sampling A detailed description of the methods is provided in the Biology Procedures Manual PJV 2004b. These sampling procedures were largely followed during A brief description of the major sampling techniques is provided below, with notes regarding any substantial deviations from the standard methods Beach seining Beach seine net sampling in the Lagaip/Ok Om river system is difficult, as the nature and extent of exposed sand and/or gravel bars suitable for this sampling technique are highly dependent on the river level at the time of sampling. Lower than normal river levels for seine net sampling may result in the only available sand bars having silt deposits below the water line. Higher than normal riverlevels may result in no exposed sand bars at all, or very limited extents of suitable areas. The standardised beach seine sampling involves collection of six replicate hauls per site. All prawns and juvenile fish caught in each net haul are put into separate polyethylene sample bags, taken to the laboratory or field processed for remote sites and sorted by species, counted, measured and weighed. Prawns may be kept alive for purging of gut contents for tissue sampling see below. Braille poles are attached to the net, and the net is hauled perpendicular to the bank to full stretch, with the central cod end downstream. It is then hauled fully open for approximately 10 m, and then swept to the bank to cover an area of approximately 100 m 2. Beach seine sampling in the Strickland River at Tiumsinawam is done similarly, using the same net, but with a 20 m haul length. Figure 1 Hauling in a beach seine net at a site in the upper catchment.

270 2.1.2 Hook-and-line Hook-and-line sampling is used only to provide specimens for tissue samples. It is not used as a method for assessing population densities or relative abundance because it is not based on standardised effort. Fishing lines, consisting of approximately 20 m of approximately 6 kg breaking strain nylon monofilament fishing line, a size 6 fishing hook, usually of a mustard, suicide, or O Shaughnessy style, and a small lead sinker, are given to local villagers. The villagers are then instructed to collect bait and use the fishing lines to collect the target species from the sampling site area. Although it is known to be a variable effort procedure, it is effective at meeting the objective of catching sufficient numbers of the targeted fish species for tissue metal concentration analysis, which is otherwise difficult to achieve. Supervision of the villagers is sometimes required to ensure that the sampled fish have in fact originated from the sampling site. Care is taken to ensure that the origin of the catch is known, so fish caught by villagers from other areas or streams are not included in the specimens collected for tissue sampling. This is routinely checked by interviewing the fishers when they return with their catch, but is confirmed where possible by direct observation of their activities. All mountain tandans Neosilurus equinus are put into polyethylene sample bags, and brought to the laboratory where they are measured, weighed and dissected to remove tissue samples, or are processed in the field. Figure 2 Hook-and-line sampling of mountain tandan Gill netting The standard sampling effort for gill nets differs between sites. However, the standard effort for gill net sampling for all sites involves one set period only. If the nets remain in the water after this time, it is recorded as non-standard effort, and used for tissue specimen collection only. An unreplicated net set incorporating a greater range of mesh sizes was used up to 1995 at the Lake Murray sites and 1997 at Tiumsinawam and the Tomu River. Replicated gill net sampling at Tiumsinawam/Tomu since 1997 has consisted of up to three sets containing one each of 76, 90 and 100 mm stretched mesh size gill nets. Three replicate sets have been used consistently since 2001, but fewer than three sets were typically used before The nets are set for a 24 h period, with smaller meshed nets set upstream of the larger nets. Each net is firmly tied to the bank in an area away from the main current, or at the upstream

271 end of a backwater where available. The net is set approximately 30 to the bank, and a float tied to the end of the head-rope, and a weight to the end of the lead-line. In Lake Murray gill net sampling targets only large fish species, with monofilament nets of 130, 150 and 175 mm stretched mesh used. Nominally, three sets containing one of each mesh size are used. The nets are set overnight between 1600 and 0800 at each site, rather than for a full 24 h period, to permit combining gill net sampling and purse seine sampling on the one day. The nets are set perpendicular to the lake shoreline in sheltered bays at each sampling site. Methods of setting are similar to those for the Strickland River sites, except that the nets are set perpendicular to the bank. Solid objects can be difficult to locate on the lake shore, so floating grasses or bamboo poles are often used as anchoring points. In some instances, it has been simplest to tie both ends of the net to bamboo poles, rather than relying on a weight to hold the distal end in place. The bamboo poles are cut to a length greater than the depth of the water to be sampled, and sharpened at the thickest end. They are then driven into the bed sediments, and checked that they are held firmly in place before the nets are tied to them. Figure 3 Gill net sampling in the Tomu River Prawn trapping Prawn trap sampling commenced as a routine sampling method in Collapsible box traps, mm, with funnel openings at each end, are used to collect prawns, Macrobrachium spp., at the upper catchment and lower Strickland region sites. The traps are baited, usually with tinned fish, and deployed around snags and backwaters. The traps are left for varying periods depending on water conditions and catch rates, to obtain sufficient specimens for tissue sampling, with checking of the catch occurring in the morning and periodically during the day and night between other sampling activities. Ten traps are set at each site. Prawn trap sampling is not conducted in a quantitative manner, and is not used for comparison of catch rates between sites.

272 Figure 4 Collapsible box traps, with funnel openings at each end, and a bait pocket used to collect prawns. Two prawns can be seen in the trap Hydroacoustics Sampling was conducted between the 12 th and 17 th of May Sampling was conducted using a Biosonics DTX split-beam echosounder with a frequency of 200 khz and a beam angle of 6. A differential GPS unit was used to achieve accurate position recording for the transducer for all pings. The hydroacoustic equipment, which is powered by a 12 V battery, was set up in a PJV 6 m fibreglass dinghy. A portable transducer mount was fixed to the gunwale by clamps, and the sounder and signal processing equipment housing placed on a wooden crate to keep them above the bilge water. The boat was equipped with a tarpaulin to provide the instrumentation with shelter during rain storms. Figure 5 shows the instrumentation setup. The transducer was set at a shallow angle downward from horizontal, to maximise the effective range that could be sampled, while maintaining sufficient echo-signal strength from the bottom for reliable bottom detection. Typically this angle was from horizontal. Therefore, range in subsequent analyses is correlated with depth, but is not equivalent to depth from the water surface.

273 Figure 5 Typical Hydroacoustic set up for sampling Hydroacoustic sampling at each floodplain site consisted of establishing a standard transect track in a part of the lake that was found to be as clear of macrophytes and snags as possible, and then at least five night-time transects were recorded along that track. Selection of the sites was based on those sampled during the 2004 project and whether access was possible for the floodplain oxbow sites. The PJV house at the SG5 gauging station was used as a base-camp for the lower Strickland River floodplain sampling. The only site that could be sampled at Lake Murray Maka was sampled on the 17 th of May 2009 and the Strickland River floodplain sites, Oxbow 3, Zongamange, Avu and Levame, were sampled on 12 th, 13 th, 14 th and 15 th of May, During the afternoon of each day of sampling the team moved out to the area of each site where GPS coordinates for a 15 minute transect were recorded. In 2009 the site in Lake Murray was not able to be sampled in the area that has been historically sampled using purse seine netting due to landowner intervention. Another site was sampled in the Maka area away from the village. The average speed of the dinghy during data collection was approximately kt/h equating to approximately 1100 to 1400 m transects. The data were analysed using Visual Analyzer Version Biosonics This program allows the user to visually check the files for accurate bottom tracking to ensure fish at the bottom of the water-body are recognised and any objects that remained stationary between transects these are discounted as being snags or macrophytes. After the files were adjusted for bottom tracking and stationary objects an analysis of fish density in grams per cubic metre g/m 3 was undertaken. Between-site and between-year comparisons were made using ANOVA designs with the S-Plus statistical software Insightful 2007, using plots of residuals to check the assumptions of homogeneity of variance and normality of residuals. 2.2 Tissue sampling Fish Sampling of liver and muscle tissue from fish was done in the field in most instances for Lake Murray and the Strickland/Tomu samples, but mountain section samples were generally returned to the laboratory for dissection but field processing is not uncommon. Fish dissections were

274 performed on fresh polyethylene sheets. Precautions were taken during dissection to prevent contamination of tissues by changing scalpel blades between fish batches, having the dissector and assistants wear vinyl surgical gloves, and washing all tissues and dissecting equipment with distilled/deionised water before and after each dissection. Liver samples were collected by first using a lint-free cloth and/or tissue paper to remove surface slimes. The body cavity was opened with a clean surgical stainless steel scalpel blade or stainless steel knife, taking care to avoid touching the liver. Stainless steel forceps were used to expose the liver. A clean surgical stainless steel scalpel, rinsed in high purity water, was used to remove the liver. The excised liver was placed in a newly labelled plastic bag and frozen. Usually, the whole liver was removed for analysis. Approximately, 5-50 g of the dorso-lateral muscular tissue of targeted fish species was dissected after the skin was removed Prawns Prawn samples were prepared in two ways. All prawns were individually washed in clean water at the sampling location. Some samples, particularly specimens that died or were damaged during collection, were individually bagged and frozen immediately. These samples are referred to as unpurged and were not used in this report. Specimens in good condition were held in aerated containers of water from the collection site for 48 h after collection. After purging the specimens were individually bagged and labelled. These samples, collected after evacuation of the gut contents, are referred to as purged samples. Prawn samples were dissected while partially frozen, so that thawed fluid from individual tissues did not mix. The cephalothorax was separated from the abdomen, and then the exoskeleton was removed from the latter. After separation, the tissues were thoroughly rinsed with distilled/deionised water, weighed separately, and packed individually in plastic bags before refreezing. The frozen samples were transported back to the laboratory on ice and then forwarded to the National Measurement Institute in Sydney for tissue metal concentration analysis 2.3 Laboratory Analysis & QA/QC All tissue samples were submitted to the National Measurement Institute Laboratories NMI, formerly the Australian Government Analytical Laboratories, AGAL in Sydney. At the NMI laboratory, tissue samples were freeze-dried and microwave digested using double distilled nitric acid, prior to chemical analysis. The concentrations of the nine elements of concern were measured using Inductively Coupled-Plasma Mass Spectrometry ICP-MS. NMI internal standard reference material samples were included by NMI in the sample batches submitted during The percentage of the expected metal concentration was recorded for each standard reference material analysis. Additionally, the standard reference material samples were analysed in duplicate by the laboratory as part of their quality control program. For the duplicate analyses, for each metal the relative proportional difference RPD between the analyses was calculated as: 2 determination 1 determination 2 RPD = determination 1 + determination 2 As a primary acceptance criterion, an up to 35% variation was considered acceptable for analyses more than three times the detection level. As a secondary acceptance criterion, a batch of duplicates was considered acceptable provided no more than one of the samples or 10% exceeded the primary criterion, whichever was the greater.

275 Blank samples and sample matrix spike samples were reported by NMI for each sample batch. Up to 25% variation in recovery of the spiked concentration was considered acceptable. 2.4 Data Analysis Abundance and diversity calculations were restricted to data collected by standard sampling methods at each site. For the purpose of statistical analysis on seine net catches, the area sampled was standardised to 100 m 2 in the upper catchment and to 200 m 2 in the lower Strickland region. Fish and prawn condition were calculated by use of the fish condition factor, K=weight g/length mm 3 x10,000 as used by PJV The data used in these calculations were not restricted to standard sampling methods, but also included fish and prawns caught using additional sampling at each site. Most statistical analyses were performed using the SPlus for Windows statistical package Insightful Inc Unless otherwise stated, a significance level of =0.05 was used in all cases. Correlation analyses used the Spearman rank correlation coefficient, which tests for monotonic rather than strictly linear relationships. One-tailed tests were used for the rank correlations to test whether or not the catches had declined. Where multiple rank correlations were performed simultaneously for a section, Bonferroni transformations were used to control the overall Type I error rate. The fit of data to ANOVA and ANCOVA model assumptions was checked by visual examination of plots of residuals. When significant differences between means were found for linear models, post-hoc multiple range tests were used to distinguish between groups of means using the best.fast procedure of SPlus. As most of the ANOVAs were unbalanced, where closely proximal means in rank order gave conflicting contrasts with a third mean, preference was given to the mean with greatest N. Some data were neither normally nor log-normally distributed. When the assumptions of the linear modelling procedures were not met and any covariates were not significant, the non-parametric Kruskal-Wallis or Wilcoxon tests were used. Where the assumptions of the ANCOVA model were not met, but the covariate or covariate main effect interaction term was significant, quasi-likelihood models were fitted where the variance was not correlated with the independent variable, otherwise an appropriate nonparametric procedure was applied to the dominant size class to remove the covariate effect. The tissue metal concentrations were log transformed prior to analysis, as metals may accumulate with age, and length is related to age by a growth curve, usually of the form: Length Kt Length Length e = Lengthmax max 0. age. class Where t is age and K is the instantaneous growth rate. Thus, where metal concentration is linearly correlated with age, it would be log-correlated with length. Therefore, length was included as a covariate in the analyses with log transformed metal as the dependent variable. The assumptions of traditional ANCOVA, equality of variance and normality of the residual variance, were checked by examination of graphs of the residuals against the model values, and normal probability plots of the residuals. In the trend analyses, extreme outlier values from years prior to 2009, as determined by graphical inspection, were excluded from the analyses.

276 3 RESULTS 3.1 Fish Abundance Upper Catchment Sampling in the Upper Catchment was achieved at all sites for each quarter during Table 1 shows the dates that sampling was undertaken at Upper Catchment sites. Table 1 Dates sampling was undertaken at Upper Catchment sites during Site 1 st Quarter 2 nd Quarter 3 rd Quarter 4 th Quarter Wasiba /03/ /05/ /08/ /11/2009 Wankipe 15 21/03/ /06/ /08/ /11/2009 Ok Om 80 04/01/ /05/ /08/ /12/2009 Kuru River /01/ /05/ /09/ /12/2009 Pori River /03/ /06/ /08/ /11/2009 Table 2 presents the total catch of aquatic species from the upper catchment sites in The three reference sites recorded the greatest species richness, followed by Wankipe and Wasiba. Mountain tandans, Neosilurus equinus, and freshwater prawns, Macrobrachium handschini, the species targeted for tissue sampling, were the most abundant species caught at each site. A total of 110 fish and prawns were caught in the Lagaip River at Wasiba by seining, trapping and angling during single day sampling trips in Mountain tandans and freshwater prawns were the main two species caught. N. equinus was the dominant species caught, comprising 38% by numbers and 94% by weight of the total catch, while M. handschini comprised 41% of the catch by number and 4% by weight. A spearman rank correlation of biomass and number of prawns caught at Wasiba from 2000 to 2009 indicated a significant declining trend indicating that less prawns are being caught at this site Figure 6. Whether this is an artefact of the variability of catches at this site due to the very limited areas of suitable sand bars for beach seining exposed during extreme high and low flows, resulting in lower catches will hopefully be identified with the use of different techniques in At Wankipe, standardised seine netting and non-standardised prawn trapping and angling caught a total of 197 fishes and prawns, comprising four species. Mountain tandans, N. equinus, and the freshwater prawn, M. handschini were the dominant species caught during the 2009 sampling period. M. handschini constituted 39% of the catch by numbers and 3% by weight, while N. equinus constituted 50% of the total catch by numbers and 81% by weight. By Kruskal-Wallis rank sum test, species richness, abundance and biomass of fish and prawns caught by standardised seine netting have not changed over time. For fish and prawns, the average number caught in 2009 was no different from that caught during the previous eight sampling periods. Spearman s rank correlation found no significant correlations over the period 2000 to At the Ok Om reference site, a total of 238 fish and prawn specimens were caught by both standardised and non-standardised sampling. Mountain tandans, N. equinus and freshwater prawns, M. handschini, were the dominant species caught. N. equinus comprised 66% of the total catch by numbers and 90% by weight, while M. handschini comprised 20% of the total catch by numbers and 2% by weight. Standardised sampling at Ok Om during 2009 was no different from sampling undertaken in the previous eight years of monitoring, except for 2008 where standardised

277 sampling did not catch any fish or prawns due to low flows and was also hindrance by land-owner disruption. At the Kuru River reference site, a total of 159 specimens were caught by the non-standardised sampling methods of trapping and angling during N. equinus and M. handschini, were the dominant species caught. N. equinus comprised 75% of the total catch by number and 93% by weight, while M. handschini constituted 9% of the catch and 0.5% by weight. No standardised seine net sampling is carried out at this site because there are no sandbars. At the Pori reference site, a total of 300 fish and prawns were caught during the 2009 sampling period. Freshwater prawns, M. handschini and, mountain tandans, N. equinus, were the dominant species caught. M. handschini comprised 34% of the total catch by numbers and 7% by weight, while Mountain tandans comprised 39% of the total catch by numbers and 77% by weight. Standardised seine net sampling is not possible at this site because there are no sandbars. Table 2 Species richness, abundance and biomass of aquatic species caught in the upper catchment during Site Wasiba Wankipe Ok Om Kuru River Pori River Site No Genera Number of species Number of specimens Biomass kg

278 Figure 6 Abundance and biomass of fish in standard seine net catches at the three main upper catchment sites over time.

279 Figure 7 Abundance and biomass of prawns in standard seine net catches at the three main upper catchment sites over time Lower Strickland ;;4,& & 777 < 7 & & < Table 3 shows the dates that sampling was undertaken at Lower Strickland River sites throughout Sampling at Bebelubi and Baia River were only completed in the second and fourth quarter of 2009.

280 Table 3 Dates sampling was undertaken at Lower Strickland sites during Site 1 st Quarter 2 nd Quarter 3 rd Quarter 4 th Quarter Tiumsinawam 19 30/01/ /04/ /07/ /10/2009 Bebelubi /04/ /10/2009 Tomu /02/ /04/ /07/ /10/2009 Baia /04/ /10/2009 Table 4 summarises the total catches at the four lower Strickland sites quantitatively sampled during 2009, and indicates that more species and genera were caught at Tiumsinawam than the Tomu River, Bebelubi and Baia River sites. The giant freshwater prawn, Macrobrachium rosenbergii, was the numerically dominant species caught from the Strickland River at Tiumsinawam, comprising 56% by numbers and 1% of the total weight. The next most abundant species was the sharp-snouted catfish, Potamosilurus macrorhynchus, which constituted 10% by numbers and 34% by weight of the total catch. Potamosilurus robertsi was the most numerically abundant species caught at the upstream Strickland River site, Bebelubi, comprising 25% of the catch by numbers, and 34% of the total weight. The prawn, Macrobrachium lorentzi, was the second most commonly caught species, contributing 19% by numbers and 0.2% by weight In the Tomu River, cross-fingered prawn, M. latidactylus was the most abundant species caught, contributing 45% of the total catch by numbers and 0.4% by weight. P. macrorhynchus was the most abundant caught species by weight from the Tomu River, constituting 12% by numbers and 27% by weight. In the Baia River, the upstream Strickland River reference site, Macrobrachium lorentzi was the most abundant species, comprising 48% by numbers and contributing 1.5% of the catch by weight, with the prawn, M. latidactylus, the second most abundant species, contributed 23% by numbers and 0.3% by weight. Table 4 Biomass and species richness for aquatic species caught in the lower Strickland River sites in Sampling site Tiumsinawam Bebelubi Tomu Baia Site No Genera Number of species Number of specimens Biomass kg

281 Gill Net Sampling Gill net sampling in the lower Strickland region was conducted in the Strickland River at Tiumsinawam, Tomu River, Baia River and Bebelubi during There were no significant between-site differences in the number of species, Margalef s diversity, number of fish caught per net set or the average biomass per set Figure 8. Figure 8 Gill net catches per standard set of three nets for the Strickland River at Tiumsinawam and the Tomu River during The catches for both Tomu River and Tiumsinawam were typical of the majority of catches in recent years Figure 9. There was significant decreasing trend detected for the number of species caught at Tiumsinawam and the biomass from 2000 to 2009 using Spearman s rank correlation test which was matched by the reference site at Tomu River.

282 Figure 9 Gill net catches per standard set of three nets for the Strickland River at Tiumsinawam and the Tomu River during over the period 2000 to Beach Seine Sampling Beach seine net sampling in the lower Strickland River region during 2009 was conducted at Tiumsinawam, Baia and Bebelubi but specimens were only caught at Tiumsinawam Figure 10 and Figure 11. Therefore, between site comparisons were not undertaken. Rank correlations of the number of species of fish per haul, Margalef s diversity index per haul, and the number and biomass of fish per standardised haul 200 m 2 were carried out for the period 2000 to No significant correlations were detected for fish in standardised seine net catches at Tiumsinawam from 2000 to 2009.

283 "# "# # # Figure 10 Number of species, Margalef s diversity, number and biomass of fish in beach seine sampling at Tiumsinawam between 2000 and As prawns were not identified to species before , Spearman s rank correlations on number of specimens and biomass of prawns per standardised haul were conducted only for the 2003 to 2009 period. Rank correlations indicated no significant trends for number of prawns and biomass for standardised seine net sampling at Tiumsinawam between 2003 and Before this time, Macrobrachium rosenbergii was recognised, but all other species were identified as Macrobrachium sp.

284 # # # # Figure 11 Number of species, Margalef s diversity, number and biomass of prawns in beach seine sampling at Tiumsinawam between 2000 and Conclusions Evidence of a possible mine related impact was detected at Wasiba for prawn number and biomass in rank correlation assessments off catches from 2000 to No evidence supporting a mine-related impact to the species richness, diversity abundance or biomass of fish or prawns was found for any of the other sites for the year 2009, nor in rank correlation assessments of trends over the time period 2000 to Lower Strickland Off River Water Bodies and Lake Murray Hydroacoustic sampling was undertaken at Maka, in Lake Murray and at the Strickland River off river water bodies, Oxbow 3, Avu, Levame and Zongamange in May Results for the hydroacoustics fish density studies of the two blocked valley lakes are presented in Table 5. Table 5 Average fish density g/m 3 for blocked valley lake sites Site Density g/m 3 Avu Maka

285 A test of goodness of fit of the lakes data using a Kolmogorov-Smirnov test indicated that the observations were not considered to be from the same distribution p= Therefore the analysis for between-site differences was undertaken using a Kruskal-Wallis rank sum test, the results of which indicated that fish density was significantly higher p=0.009 at Avu compared with Maka Figure 12. It should be noted that there were a lot of floating patches of macrophytes at Avu, which can interfere with measurement of fish density, and that this may be the cause for the higher density value recorded. Fish density g/m Avu Site Maka Figure 12 Fish density g/m 3 for blocked valley lake sites Results for the hydroacoustics fish density studies of the oxbow lake sites are presented in Table 6. Table 6 Average fish density g/m 3 for oxbow sites Site Density g/m 3 Levame Oxbow Zongamange Fish density between the oxbow sites was tested using a Kruskal-Wallis rank sum test with the results indicating that there were no significant differences between any of the sites Figure 13. Differences in fish density between years for sampling undertaken in 2008 and 2009 were investigated using two sample t tests or Kruskal-Wallis rank sum tests. At the lake site, Avu, fish density was seen to be significantly greater p= during 2008 when compared with As has been stated previously, this lake is shallow and contains racks of free floating macrophytes which may interfere with the mapping of fish density. In future sampling trips an effort to ensure that the plotted transect is clear of such debris should reduce this interference in the sampling. Maka was also observed to have significantly different p=0.003 fish density between years with 2009 fish density greater than that observed in Fish density at Zongamange was also significantly different p= between years with 2008 fish density greater than that seen in No significant difference was detected between years for sites Levame and Oxbow 3.

286 The results from the hydroacoustic sampling from 2009 indicated that the potentially impacted site upstream of the Herbert River confluence at Oxbow 3 showed similar, if not higher, fish density, indicating no mine derived effect. Fish density g/m Levame Oxbow_3 Zongamange Site Figure 13 Fish density g/m 3 for oxbow lake sites 3.2 Fish Condition Upper Catchment Figure 14 presents box plots of the condition index K for specimens of mountain tandan, Neosilurus equinus and fresh water prawn, Macrobrachium handschini from the upper catchment during By ANOVA, significant differences p<0.05 were detected between sites for N. equinus but none indicated mine related impacts due to the Lagaip River fish having better condition than those from the reference sites. For M. handschini, significant differences were detected between sites for samples collected at Wasiba where the condition of the prawns were significantly p<0.001 lower than the condition of the prawns collected from the reference site at Pori River. No significant differences were observed between the prawns from Wasiba and the other reference sites, particularly site Ok Om, but this should be noted for follow up in 2010 reporting and monitoring.

287 #*## %&'& +#& %&'& Figure 14 Box-plots of condition index K values for mountain tandans, Neosilurus equinus, and fresh water prawns, Macrobrachium handschini, from upper catchment sites. 0 & D Table 7 presents the significant Spearman s rank correlation results for mountain tandans and freshwater prawn condition for the period 2000 to Figure 15 shows dot plots of condition index by year for mountain tandans and freshwater prawns. There were no significant decreasing trends in specimen condition at any of the impact sites. Table 7 Spearman s rank correlation analysis results of significant correlations in fish and prawn conditions for period 2000 to 2009 in the upper catchment sites. Species Wankipe Wasiba Ok Om Kuru River Pori River Neosilurus equinus Macrobrachium handschini

288 #*## #*## %&'& %&'& #*## +#& %&'& %&'& +#& +#& %&'& %&'& Figure 15 Dot plots of condition index K values for mountain tandans, Neosilurus equinus, and freshwater prawns, Macrobrachium handschini, over the period of 2000 to 2009 or where data were available at Wankipe, Wasiba and Ok Om Lower Strickland Figure 16 and Figure 17 show box plots of the condition index for sharp-snouted catfish, Potamosilurus macrorhynchus, broad-snouted catfish, P. latirostris, thick-lipped catfish, Pachyula crassilabris, giant freshwater prawns, Macrobrachium rosenbergii, and cross-fingered prawns, Macrobrachium latidactylus, from the Strickland River at Tiumsinawam and Bebelubi, and the reference sites in the Tomu and Baia Rivers. By ANOVA, the average condition index for all species analysed from Strickland River sites indicated no significant mine related impact for specimens collected in 2009.

289 # ## %&'& %&'& #+ %&'& Figure 16 Box plots of condition index K for sharp-snouted catfish, P. macrorhynchus, broadsnouted catfish, P. latirostris and thick-lipped catfish, Pachyula crassilabris from the Strickland River at Tiumsinawam and Bebelubi, and reference sites Tomu and Baia rivers in & D +#+ +#&# %&'& %&'& Figure 17 Box plots of condition index K for giant freshwater prawn, Macrobrachium rosenbergii, and cross-fingered prawn, Macrobrachium latidactylus, from the Strickland River at Tiumsinawam and Bebelubi, and reference sites Tomu and Baia rivers in & D Figure 18 and Figure 19 show dot plots of condition index for fish and prawns in the period 2000 to Table 8 presents the significant Spearman s rank correlation results for fish and prawns in the lower catchment sites. Significant decreasing trends were observed at Tiumsinawam for P. crassilabris and M. rosenbergii that were matched by decreasing trends for samples from Tomu River. P. macrorhynchus collected from Tiumsinawam were observed to have a significant

290 decreasing trend in average condition which was not observed in samples collected from the Tomu River over the same time period. While this indicates there may be some mine related impact on the condition of P. macrorhynchus at Tiumsinawam this was not reflected by the between site analysis of specimen condition for 2009, but should be noted for follow up in the 2010 analysis and reporting. # # %&'& %&'& ## ## %&'& %&'& #+ #+ %&'& %&'& Figure 18 Dot plots for between year differences in condition index K for sharp-snouted catfish, Potamosilurus macrorhynchus, blunt-snouted catfish, P. latirostris and thick-lipped catfish, Pachyula crassilabris in the Strickland River at Tiumsinawam and Tomu River over the period 2000 to 2009.Table 8 Spearman s rank correlation analysis results of significant correlations in fish and prawn conditions for period 2000 to 2009 or where data was available at lower Strickland sites.

291 Specimen Tiumsinawam Tomu Potamosilurus latirostris Potamosilurus macrorhynchus Pachyula crassilabris Macrobrachium latidactylus Macrobrachium rosenbergii #+ +#&# %&'& %&'& +#+ +#&# %&'& %&'& Figure 19 Dot plots for between year differences in condition index K for giant freshwater prawn, Macrobrachium rosenbergii, and cross-fingered prawn Macrobrachium latidactylus at Tiumsinawam and Tomu River for the period 2000 to Conclusions In the upper catchment, there was a significant decline observed for prawn condition at Wasiba when compared with prawns from Pori River but no difference was detected when compared with the other two reference sites. Fish condition was not found to be different between reference and impact sites in 2009 and no decreasing trend in fish and prawn condition at impact sites was observed for specimens collected from 2000 to In the lower Strickland, there were no significant differences detected between sites indicating reduced condition of fish and prawns at Strickland River sites. A decreasing trend in condition was observed for P. macrorhynchus at Tiumsinawam that was not mirrored at the reference site at

292 Tomu River. This is the first time this trend has been detected and should be further investigated if it occurs again in Tissue Analysis Quality Assurance As has happened in previous years, tissue samples collected during 2009 were sent to NMI in four separate batches, covering samples collected from each quarter of the calendar year respectively. Laboratory quality control sample results were provided separately for each batch. For Quarter 1, the laboratory analysis included four blank samples, four laboratory control samples, six duplicate samples and nine matrix spike recoveries. All results from these samples were within acceptable quality limits. Duplicate samples were found to be outside the required RPD value for a range of metals. This included arsenic and nickel on two occasions, and copper, chromium and mercury on one occasion. All matrix spike analyses, conducted on the same samples as the duplicate analyses, had recoveries within the acceptable range. Overall, the laboratory quality control for this batch was acceptable according to the criteria specified in Section 2.3. For Quarters 2, 3 and 4, four blank samples and four laboratory control samples, six duplicate samples and eight matrix samples were analysed in each. All duplicate analyses were within the acceptable RPD limits. All matrix spike analyses on these duplicate samples had recoveries within the acceptable range. Overall, the laboratory quality control for these batches was acceptable according to the criteria specified in Section 2.3. The use of field blanks in 2009 was a major improvement on recent years with 31 samples submitted as field blanks throughout the year compared with seven in This level of field blanks need to be at least maintained if not increased for future programs, with an aim to achieve at least 10 field blanks per quarter. During quarter 1 and half of quarter 2, samples of Potamosilurus macrorhynchus where submitted for analysis as field blanks, while for the remainder of quarter 2 and quarters 3 and 4 samples of Lates calcarifer samples where submitted for analysis as field blanks. The original sample of P. macrorhynchus was collected from Tiumsinawam on the 24 th of August 2008 and the data used to compare with the field blank samples submitted during 2009 was the results of the analysis of this sample as a field blank during Although this is not ideal, the use of the data from 2008 allowed for the calculation of upper and lower limits to assess the quality of the 2009 field blanks. The sample of L. calcarifer was collected from Miwa on the 21 st of May 2009 for the sole purpose of being used as a field blank. Enough material was collected for use as field blanks for a number of years. Six samples were submitted for metal analysis to establish the upper and lower limits for comparison with field blanks submitted with samples throughout the remainder of Results of field blanks used in 2009 were variable, with indications of possible contamination during sample processing and analysis laboratory sample handling and analysis instrumentation variation although, as seen above, most laboratory QA/QC was considered acceptable. Table 9 outlines the results that were outside the acceptable QA/QC limits for field blanks as outlined in Section 3.3. The complete field blank data set are presented in Appendix 4. While some contamination has been detected in the field blanks used in 2009, the effort to use field blanks greatly improved compared with previous years and should be maintained. The contamination seen in samples at low levels may be due to the repeated thawing and freezing of the fish flesh used for field blanks. Where field blanks were found to be above the 85 th percentile, results for those metals should be interpreted with caution as confidence in these results would be lower than expected. Future tissue sampling will need to be done with extra care to avoid this type of contamination.

293 Table 9 Field blank results outside of acceptable QA/QC limits for all quarters of 2009 " # " # 3.4 Tissue Concentration Analysis Graphs of tissue metal concentrations for all species, metals and tissue types sampled and analysed in 2009 are presented in Appendix 1. The following sections present the findings of the analysis of the tissue metal concentrations for the upper catchment and the lower Strickland River sites Upper Catchment The sites used for collection of samples from the upper catchment during 2008 were those used since 2004 PJV 2005, 2006, 2007, 2008, 2009 being, the reference sites, Ok Om, Pori River and Kuru River and the impacted Lagaip River sites, Wasiba and Wankipe Prawn Macrobrachium handschini cephalothorax and abdomen flesh Macrobrachium handschini cephalothorax samples collected from the sites downstream of the mine of Wankipe and Wasiba in 2009 were found to have significantly elevated average or lengthadjusted average concentrations of arsenic, cadmium and lead compared with the reference sites at Ok Om, Pori River and Kuru River Figure 20. Average copper concentrations in cephalothorax samples collected from Wasiba were found to be significantly elevated compared with those collected from Ok Om and Kuru while zinc and selenium length-adjusted concentrations were found to be significantly elevated at Wankipe and Wasiba when compared with those from Pori River Figure 20. The results of stepwise between-site ANCOVA analyses of metal concentrations in purged prawn cephalothorax samples are provided in Appendix 2.

294 As [mg/kg] Cd [mg/kg] Wasiba Wankipe Ok Om Pori Kuru 0 Wasiba Wankipe Ok Om Pori Kuru 100 Wasiba 50 Pb [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Zn mg/kg Pori Kuru Length Wankipe Ok Om Wasiba Wasiba Pori Wankipe Pori Wankipe Cu mg/kg Se mg/kg Kuru Ok Om 0 Kuru Ok Om Length Length Figure 20 Concentrations in M. handschini cephalothorax samples collected during 2009 for metals discussed in the text. E The average concentrations of cadmium for abdomen flesh samples collected from Wankipe and Wasiba during the year were significantly greater than for any of the reference sites Figure 21. For lead, average concentrations at Wankipe were found to be significantly greater than those at all reference sites, selenium and zinc length-adjusted average concentrations at Wankipe and Wasiba were found to be significantly elevated compared with those at Pori River while copper average concentrations were significantly elevated at Wankipe compared with samples from Pori River Figure 21. No other metals had between-site differences that were potentially indicative of mine-related alteration of metal bioavailability. The results of stepwise between-site ANCOVA

295 analyses of metal concentrations in purged prawn abdomen flesh samples are provided in Appendix Cd [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Pb [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Se [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Wasiba Cu [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Zn mg/kg Pori Kuru Length Wankipe Ok Om Figure 21 Concentrations in M. handschini abdomen flesh samples collected during 2009 for metals discussed in the text. E Trends in prawn tissue metal concentrations were examined by use of Spearman s rank correlation for data bracketed in the time periods 2006 to 2009 and for the last two years of sampling, 2008 and This tests for overall monotonic that is, consistent in terms of direction trends without any assumption of linearity of that trend. The results are summarised in Table 10. For M. handschini cephalothorax samples over the longer time period, the only significant correlations at a Lagaip River site that were not matched by a similar trend at least at one reference site were increasing trends in arsenic and mercury at Wasiba. The trend for unmatched increasing average arsenic at Wasiba was also observed in the abdomen flesh. An increase in average zinc concentrations in abdomen flesh from Wasiba was also unmatched by any of the reference sites. Average selenium concentrations were seen to increase over the longer time period at all sites for the cephalothorax samples but not for the flesh samples. An unmatched short term trend was observed in Wankipe prawn cephalothorax samples for average arsenic and also for average cadmium in prawn flesh samples collected at Wasiba. In contrast to what was observed last year where the declining trend for a number of average metal concentrations at both the reference and impact sites over 2007 and 2008 for prawn abdomen flesh samples where no increasing trend was detected was reversed for the 2008 to 2009 period which saw a number of metals increase at both reference and impact sites. As was observed over the longer time period the concentrations of selenium in both cephalothorax and flesh samples had an increasing trend at most sites.

296 Table 10 Direction of Spearman s rank correlation coefficients for average metal concentrations in M. handschini cephalothorax and abdomen flesh samples over the full period of collection of purged samples and for the last two years of sampling. D indicates declining trend. U indicates upward trend. 0 indicates no significant trend. indicates insufficient variance for analysis. Cephalothorax Reference Impact Reference Impact Metal Ok Om Pori Kuru Wankipe Wasiba Ok Om Pori Kuru Wankipe Wasiba Cu U 0 0 D 0 U 0 0 D D Cd 0 U 0 U U 0 U Pb D D D D 0 0 D Zn U U Cr D 0 0 D Ni U 0 U U 0 0 D Se U U U U U U 0 U U 0 As D D 0 0 U U 0 Hg 0 D 0 0 U D Abdomen Flesh Reference Impact Reference Impact Metal Ok Om Pori Kuru Wankipe Wasiba Ok Om Pori Kuru Wankipe Wasiba Cu 0 0 U 0 0 U 0 U U U Cd - U 0 0 U U Pb Zn U U 0 0 U U Cr D D 0 0 Ni D 0 U Se U 0 U U U As D U 0 U 0 U U Hg

297 Mountain Tandan Neosilurus equinus liver and flesh For N. equinus liver samples significant differences between sites downstream of the mine and reference sites were detected for a number of metals but for no metal were both downstream sites significantly elevated compared with all reference sites. Average cadmium and length-adjusted average lead concentrations were significantly elevated at both Wankipe and Wasiba compared with Pori River and Kuru River but not Ok Om Figure 22. The length-adjusted average selenium concentration for Wasiba samples was found to be significantly higher than the levels detected in samples from Pori River Figure 22. The results of stepwise between-site ANCOVA analyses of average metal concentrations in mountain tandan liver samples are provided in Appendix Wasiba 0.1 Cd [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Pb mg/kg Pori Kuru Length Wankipe Ok Om Wasiba Pori Wankipe Se mg/kg 6 3 Kuru Ok Om Length Figure 22 Concentrations in N. equinus liver samples collected during 2009 for metals discussed in the text. E

298 For N. equinus flesh samples, significant differences between Wasiba and all three reference sites were detected for concentrations of selenium while flesh samples from Wankipe contained higher selenium concentrations than Pori River samples Figure 23. The only other difference observed between reference and impact sites for N. equinus flesh samples was for zinc concentrations at both Wasiba and Wankipe compared with samples collected from Kuru River Figure 23. The results of stepwise between-site ANCOVA analyses of metal concentrations in mountain tandan flesh samples are provided in Appendix Wasiba 12 Wasiba Se mg/kg 0.0 Pori Wankipe Zn mg/kg Pori Wankipe Kuru Ok Om Kuru Ok Om Length Length Figure 23 Concentrations in mountain tandan flesh samples during 2009 for metals discussed in the text. Trends in N. equinus tissue metal concentrations were examined by use of Spearman s rank correlation over the time periods 2000 to 2009 and for the last two years of sampling, 2008 and The results are summarised in Table 11. For liver samples there were no unmatched increasing trends seen for any metals over the longer and shorter term where most metals either remained steady or decreased in concentration. For flesh samples, unmatched inclining trends at downstream sites and not reference sites were seen for zinc and selenium at Wankipe over the longer period of data collection similar to that seen in the previous year data. Over the shorter term, increasing trends in copper concentrations at Wasiba and zinc concentrations at Wankipe were not matched at any of the reference sites.

299 Table 11 Direction of Spearman rank correlation coefficients for metal concentrations in N. equinus liver and flesh samples between 2000 and 2009 and for the last two years of sampling. D indicates declining trend. U indicates upward trend. 0 indicates no significant trend. indicates insufficient variance for analysis. Liver Reference Impact Reference Impact Metal Ok Om Pori Kuru Wankipe Wasiba Ok Om Pori Kuru Wankipe Wasiba Cu D D D D Cd 0 D 0 D 0 U D Pb D 0 0 D 0 U Zn U D D 0 D D 0 Cr D 0 D D D 0 0 Ni U 0 0 D U Se 0 0 D 0 D D D As 0 U U D U Hg U 0 D D Flesh Reference Impact Reference Impact Metal Ok Om Pori Kuru Wankipe Wasiba Ok Om Pori Kuru Wankipe Wasiba Cu D 0 U 0 U 0 0 D 0 U Cd D Pb D 0 0 D Zn D 0 0 U U 0 Cr D 0 D D 0 D 0 D 0 0 Ni 0 U U U 0 U Se U 0 U 0 U U 0 As 0 0 D D 0 0 D Hg D 0 D U Sorbitol dehydrogenase analysis It had been recommended on several occasions PJV 2003, 2004, 2005, 2006; Bunn et al 2006 that in light of continued evidence for enhanced bioavailability of some metals in the Lagaip River that effort should be made to look for any evidence of detrimental effects to the resident biota resulting from that elevation. The measurement of increased bioaccumulation of metals is merely a measurement of exposure to increased bioavailability of metals, and does not necessarily imply that there were any adverse consequences. The primary effects monitoring tool for the Biological Monitoring Programs is assessment of diversity and abundance of fish and prawns, but power analyses of this sampling program by PJV 2005 demonstrated that as implemented that program had little statistical power to detect effects short of catastrophic changes to the resident populations. In 2006 SDH analysis was undertaken on prawns collected from the upper Lagiap River sites, Wasiba and Wankipe and the reference sites, Ok Om and the Kuru River. It was found that the prawns collected from the impacted sites had elevated levels of SDH in abdomen flesh, which is an indicator of hepatocellular death caused by exposure to bioavailable contaminants. During 2009 a dedicated effort was made to collect prawns from the upper catchment sites for use in SDH analysis. Prawns were collected from Wasiba, Wankipe, Ok Om and Pori River and were sent to Curtin University in Western Australia where they underwent analysis. The results of the analysis are presented in Figure 24. A report of the investigation can be seen in Appendix 3, where the procedures for methods and analysis are given.

300 400 SDH Activity mu/g tissue Pori Ok Om Wasiba Wankipe Site Figure 24 Results of SDH analysis of prawns collected from sites in the upper catchment in 2009 The results of the analysis of SDH levels indicated that the prawns from the sites downstream of the mine had significantly greater levels of SDH in abdomen flesh than prawns collected from the reference sites. Therefore, the prawns at Wankipe and Wasiba are considered to be incurring a greater rate of hepatocellular death than those at Ok Om and Pori River. At this stage it is not known whether or not this level of hepatocellular damage is tolerable by the prawns Conclusions The tissue metal concentration analyses for samples from the upper catchment during 2009 demonstrated continued elevation of metal bioaccumulation in samples from the Lagaip River compared with the reference sites. Average cadmium was relatively elevated at both Wankipe and Wasiba in prawn cephalothorax and flesh samples and in mountain tandan liver samples as was found in the 2007 and 2008 Biology Annual Reports. Average copper was not found to be as relatively elevated in both prawn and fish samples, which differed from the findings of the 2007 and 2008 Biology Annual Reports where average copper was found to be elevated in prawn cephalothorax samples. Average lead was relatively elevated at both Wankipe and Wasiba in prawn cephalothorax and at Wasiba in prawn abdomen flesh samples and also in fish liver samples. Average selenium was elevated at both Wasiba in mountain tandan flesh and average zinc samples when compared with Pori River samples, while average zinc was elevated at Wasiba in both prawn cephalothorax and flesh when compared with Pori River samples and average arsenic was elevated at both Wasiba and Wankipe in prawn cephalothorax samples when compared with all the reference sites. An analysis of significant trends in the data collected from 2000 to present and for the last two years showed a number of decreases in metal concentrations in prawn and fish tissue types. Downward trends were detected for average copper in M. handschini cephalothorax samples at both the downstream sites for the short term analysis and for Wankipe only for the long term analysis. Other metals in prawn cephalothorax from Wankipe that had significant long term downward trends were average lead and average chromium while the only other downward trends for prawn cephalothorax samples was the short term trend for average mercury at Wasiba. Prawn abdomen flesh samples showed only one significant downward trend being long term average nickel data in samples collected from Wankipe. No other decreasing trends were detected at impact sites for prawn abdomen flesh. For the fish, N. equinus, significant decreasing trends were detected in liver tissue from the longer term data for the metals copper, zinc and selenium at Wasiba and for the metals copper, cadmium, lead, chromium, arsenic and mercury for Wankipe. Over the shorter time period average copper and selenium were seen to decrease at Wasiba while at Wankipe copper, zinc, nickel and

301 selenium were found to be decreasing. For N. equinus flesh samples collected from Wankipe downward trends were detected in the long term data for the metals cadmium, lead, chromium and arsenic. No other decreasing trends were detected for the impact sites in both the long and short term data. Upward trends in prawn cephalothorax were detected for metals cadmium, zinc, selenium, arsenic and mercury at Wasiba for the long term data while no increasing trends were found for the shorter term data. At Wankipe long term trends were observed for metals cadmium, nickel and selenium and for selenium and arsenic for the short term data. Abdomen flesh saw increasing trends evident at Wasiba for both the long and short term datasets for cadmium, zinc and arsenic and increasing short term trends for copper and selenium. There were no observed increasing trends in abdomen flesh at Wankipe in the long term data but the short term data indicated significant increasing trends for copper, zinc, selenium and arsenic. Increasing trends for the fish, N. equinus, were observed in liver samples collected from Wasiba for average arsenic in the longer term data and for average nickel in the shorter term data while no increasing trends were detected for Wankipe. Flesh samples were found to have increasing trends over the longer period for average copper at Wasiba and zinc and selenium at Wankipe while over the shorter term copper and nickel were observed to be increasing at Wasiba and zinc and selenium at Wankipe. Overall, these results demonstrate a continued persistence of mine-related elevation of bioavailability of cadmium, copper, lead, zinc, selenium and arsenic in the Lagaip River with trends in both prawns and fish indicating that for all tissue types except prawn cephalothorax that metal concentrations have remained constant. Prawn cephalothorax metal concentrations continue to increase at Wasiba with SDH enzyme analysis confirming that the prawns are under sub-organism stress. While the increasing trend of mercury in tandan flesh samples has abated in 2009 this upward trend is still occurring for selenium at Wankipe. The question of relevance of this to the status of the populations of aquatic biota was partially addressed for the first time during 2006 PJV 2007, via the use of the SDH enzyme marker of hepatic cell damage. This demonstrated elevated rates of hepatopancreas cell damage in prawns from both the Lagaip Sites compared with specimens from the reference sites, particularly the Ok Om. The SDH program was undertaken again in 2009 with prawn samples from the upper sites analysed for SDH activity. The results were similar to those observed in 2006 with the prawns from the impacted sites, Wankipe and Wasiba, having significantly elevated levels of SDH in their abdomen flesh compared with samples from Ok Om and Pori River demonstrating elevated rates of cell damage and therefore potentially inhibition of metabolic activities Lower Strickland Strickland River sites at Tiumsinawam, Bebelubi and SG5 were sampled in 2009 along with reference sites in the Tomu and Baia Rivers Giant freshwater prawn Macrobrachium rosenbergii cephalothorax and abdomen flesh Giant freshwater prawns were collected from the Strickland River at Bebelubi, the Baia River, the Strickland River at Tiumsinawam, the Tomu River and the Strickland River at SG5, during The results of stepwise between-site ANCOVA analyses of metal concentrations in giant freshwater prawn cephalothorax samples are provided in Appendix 2. Length-adjusted average cadmium concentrations in M. rosenbergii cephalothorax samples were found to be significantly higher at all the impacted sites, Tiumsinawam, Bebelubi and SG5, when compared with both reference sites, Tomu River and Baia River Figure 25. The average concentrations of lead that were detected at Tiumsinawam and SG5 were found to be significantly elevated compared with those samples collected from the Tomu River Figure 25. Length-

302 adjusted average zinc concentrations in samples from SG5 were significantly greater than samples from Baia River and Tomu River while Tiumsinawam samples were higher in zinc than Baia River only Figure 25. Average nickel concentrations were also found to be elevated at both SG5 and Tiumsinawam when compared with samples from Tomu River Figure 25. Samples collected at SG5 were also found to be significantly elevated in average arsenic concentrations compared with samples from Baia River and Tomu River Figure 25. Pb [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia Ni [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia As [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia SG5 SG Tiumsinawam Tomu Tiumsinawam Tomu Zn mg/kg Cd mg/kg Baia Bebelubi Baia Bebelubi Length Length Figure 25 Concentrations in M. rosenbergii cephalothorax samples collected during 2009 for metals discussed in the text. E The results of stepwise between-site ANCOVA analyses of average metal concentrations in giant freshwater prawn abdomen flesh samples indicated that there were significant differences between reference and impact sites for the metals copper, cadmium, selenium and arsenic. Average length-adjusted copper concentrations were detected at elevated levels at Tiumsinawam when compared with both the reference sites Figure 26. Tiumsinawam sample average cadmium concentrations were also found to be elevated compared with Tomu River samples Figure 26. It should be noted that the variance observed between the SG5 samples was greater than that seen for both reference sites both p values <0.001 which is often a precursor to significant differences between sites. This trend should be followed up in the 2010 Annual Biology Report. Average selenium levels in flesh samples from Tiumsinawam were found to be significantly elevated compared with both reference sites while SG5 was found to have significantly elevated concentrations when compared with Baia River only Figure 26. Samples collected from SG5 were also found to have significantly elevated length-adjusted average arsenic concentrations than both the reference sites Figure 26.

303 Cd [mg/kg] Se [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia 0.0 Bebelubi Tiumsinawam SG5 Tomu Baia SG5 SG Tiumsinawam Tomu Tiumsinawam Tomu Cu mg/kg 10 As mg/kg Baia Bebelubi 0 Baia Bebelubi Length Length Figure 26 Concentrations in M. rosenbergii abdomen flesh samples collected during 2009 for metals discussed in the text. E Spearman s rank correlation was used to identify trends in average metal concentrations in M. rosenbergii tissues collected from the Lower Strickland region over the time periods 2006 to 2009 and 2008 to The results are summarised in Table 12. Significant trends at sites downstream of the mine that were not matched by similar trends at reference sites for cephalothorax tissue included: Copper at Tiumsinawam decreased over the shorter time period; Lead and nickel decreased at Bebelubi over the shorter time period; Lead at Tiumsinawam decreased over the longer time period; Chromium decreased at both Bebelubi and SG5 over the shorter time period; and Arsenic at SG5 increased over the shorter time period. And for abdomen flesh: Copper increased at Bebelubi over the longer term; Arsenic decreased at Bebelubi over the longer term; Cadmium, nickel and selenium all increased at Tiumsinawam over the shorter term; and,

304 Selenium and arsenic increased at SG5 over the shorter term. Table 12 Direction of Spearman rank correlation coefficients for metal concentrations in M. rosenbergii cephalothorax and abdomen flesh samples between 2006 and 2009 and for the last two years of sampling. D indicates declining trend. U indicates upward trend. 0 indicates no significant trend. indicates insufficient variance for analysis. Cephalothorax Reference Impact Reference Impact Metal Tomu Baia Tiumsinawam Bebelubi SG5 Tomu Baia Tiumsinawam Bebelubi SG5 Cu D 0 0 Cd U U U 0 U 0 Pb 0 U D D 0 Zn U U U Cr 0 U D 0 D D Ni D D 0 Se U U U U U U U U U 0 As U Hg U D 0-0 Abdomen Flesh Reference Impact Reference Impact Metal Tomu Baia Tiumsinawam Bebelubi SG5 Tomu Baia Tiumsinawam Bebelubi SG5 Cu U 0 U 0 U 0 0 Cd D U 0 0 Pb Zn D Cr D U 0 U 0 0 D 0 D D Ni 0 U U 0 0 Se D D D D D 0 0 U 0 U As U U 0 D 0 U U 0 0 U Hg Cross-fingered prawn Macrobrachium latidactylus cephalothorax and abdomen flesh Cross-fingered prawns were collected from the Strickland River at Tiumsinawam, the Strickland River at Bebelubi, the Baia River and the Tomu River during The results of stepwise between-site ANCOVA analyses of metal concentrations in M. latidactylus cephalothorax samples are provided in Appendix 2. Average length-adjusted cadmium concentrations in M. latidactylus cephalothorax samples collected from both Tiumsinawam and Bebelubi were significantly elevated when compared with samples from both Tomu River and Baia River Figure 27. Average copper and zinc and lengthadjusted lead concentrations in samples collected from Tiumsinawam were significantly elevated when compared with samples from Baia River Figure 27. Average length-adjusted lead concentrations were also found to be elevated in samples from Bebelubi when compared with Tomu River samples Figure 27.

305 Cu [mg/kg] Bebelubi Tiumsinawam Tomu Baia Zn [mg/kg] Bebelubi Tiumsinawam Tomu Baia Se [mg/kg] Bebelubi Tiumsinawam Tomu Baia Tiumsinawam Tomu Tiumsinawam Tomu Cd mg/kg Baia Bebelubi Pb mg/kg Baia Bebelubi Length Length Figure 27 Concentrations in M. latidactylus cephalothorax samples collected during 2009 for metals discussed in the text. E Average copper concentrations in M. latidactylus abdomen flesh samples at Tiumsinawam were higher than the reference site Tomu River and average length-adjusted selenium concentrations in samples collected at Tiumsinawam were significantly elevated compared with those from Baia River Figure Tiumsinawam Tomu 0.4 Cu [mg/kg] Bebelubi Tiumsinawam Tomu Baia Se mg/kg Length Figure 28 Concentrations in M. latidactylus prawn abdomen flesh samples collected during 2009 for metals discussed in the text. E Spearman s rank correlation was used to identify trends in average metal concentrations in M. latidactylus tissues collected from the Lower Strickland region over the time periods 2006 to Baia Bebelubi 0.2

306 and 2008 to The results are summarized in Table 13. Significant trends at sites downstream of the mine that were not matched by similar trends at reference sites for cephalothorax tissue included: Copper, zinc, chromium, nickel, selenium arsenic and mercury at Tiumsinawam increased over the longer time period; Selenium increased at Bebelubi over the linger time period; Arsenic at Tiumsinawam decreased over the longer time period; Chromium increased at Tiumsinawam over the shorter time period; Lead and arsenic decreased at Tiumsinawam over the shorter time period; and Copper, lead and nickel all decreased at Bebelubi over the shorter time period. And for abdomen flesh: Cadmium, lead and arsenic decreased over the longer time period at Tiumsinawam; Chromium increased at Bebelubi over the longer time period; Arsenic decreased at Tiumsinawam over the shorter time period; and, Copper, cadmium and chromium all decreased over the shorter time period at Bebelubi.

307 Table 13 Direction of Spearman rank correlation coefficients for metal concentrations in M. latydactylus cephalothorax and abdomen flesh samples between 2006 and 2009 and for the last two years of sampling. D indicates declining trend. U indicates upward trend. 0 indicates no significant trend. indicates insufficient variance for analysis. Cephalothorax Reference Impact Reference Impact Metal Tomu Baia Tiumsinawam Bebelubi Tomu Baia Tiumsinawam Bebelubi Cu 0 0 U D Cd U 0 D 0 0 D D 0 Pb D 0 D D 0 Zn 0 D U 0 0 D 0 0 Cr 0 0 U U 0 Ni 0 0 U D Se 0 0 U U U As 0 0 D 0 U 0 D 0 Hg 0 0 U 0 D Abdomen Flesh Reference Impact Reference Impact Metal Tomu Baia Tiumsinawam Bebelubi Tomu Baia Tiumsinawam Bebelubi Cu U U 0 0 D Cd 0 - D 0 U - 0 D Pb U 0 D Zn 0 D D 0 D Cr U U 0 0 D Ni D 0 D Se 0 D 0 0 U D 0 0 As U 0 D U U 0 D 0 Hg Sharp-snouted catfish Potamosilurus macrorhynchus liver and flesh Sharp-snouted catfish samples were collected from the Strickland River at Bebelubi, the Strickland River at Tiumsinawam, Tomu River and Baia River in The results of stepwise ANCOVA analysis of between-site comparisons are provided in Appendix 2 for liver and flesh samples. Average length-adjusted selenium and mercury concentrations in flesh samples of P. macrorhynchus from Bebelubi were found to be significantly elevated compared with those from both reference sites Figure 29. This seems to be driven by two larger fish caught at Bebelubi and upon analysis excluding these specimens no significant differences between Bebelubi and the reference sites were detected. No other between-site significant differences were detected for flesh samples collected in 2009.

308 Tiumsinawam Tomu Tiumsinawam Tomu Se mg/kg Baia Bebelubi Hg mg/kg Baia Bebelubi Length Length Figure 29 Concentrations in P. macrorhynchus flesh samples collected during 2009 for metals discussed in the text. Liver samples taken from P. macrorhynchus collected from Bebelubi were found to be significantly elevated in average concentrations of length-adjusted cadmium, lead, selenium and mercury and also for average zinc concentrations when compared to samples collected from both reference sites Figure 30. No other significant between site differences were detected. Spearman s rank correlation was used to identify trends in average metal concentrations in P. macrorhynchus tissues collected from the Lower Strickland region over the time periods 2000 to 2009 and 2008 to The results are summarised in Table 14 Significant trends at sites downstream of the mine that were not matched by similar trends at reference sites for flesh tissue included: Longer term data indicates an increase in zinc and selenium concentrations at Tiumsinawam; Copper, selenium and mercury at Bebelubi increased over the longer period; Lead, chromium and arsenic at Tiumsinawam decreased over the longer time period; Arsenic decreased at Bebelubi over the longer time period; Copper, zinc and selenium increased at Tiumsinawam over the shorter time period; and, Selenium increased at Bebelubi over the shorter time period. And for liver tissue: Copper, cadmium, zinc, selenium and arsenic increased at Tiumsinawam over the longer time period; Cadmium and arsenic increased at Bebelubi over the longer time period; Chromium decreased at Tiumsinawam over the longer time period; Cadmium at Tiumsinawam increased over the shorter time period.

309 Tomu Tomu Tiumsinawam Tiumsinawam Cd mg/kg 7 3 Pb mg/kg Bebelubi Bebelubi Length Length Tomu Tomu Tiumsinawam Tiumsinawam Se mg/kg 10 5 Hg mg/kg 10 4 Bebelubi 0 Bebelubi Length Length Zn [mg/kg] Bebelubi Tiumsinawam Figure 30 Concentrations in P. macrorhynchus liver samples collected during 2009 for metals discussed in the text. E Tomu Baia

310 Table 14 Direction of Spearman s rank correlation coefficients for metal concentrations in P. macrorhynchus liver and flesh samples between 2000 and 2009 and for the last two years of sampling. 1 5 & ;7E77 7 Liver Reference Impact Reference Impact Metal Tomu Baia Tiumsinawam Bebelubi Tomu Baia Tiumsinawam Bebelubi Cu 0 0 U Cd 0 0 U U 0 - U 0 Pb D Zn 0 0 U Cr U - D Ni Se 0 0 U As 0 0 U U Hg U 0 U U Flesh Reference Impact Reference Impact Metal Tomu Baia Tiumsinawam Bebelubi Tomu Baia Tiumsinawam Bebelubi Cu D 0 0 U 0 - U 0 Cd Pb 0 - D Zn D 0 U U 0 Cr 0 0 D Ni U Se 0 0 U U 0 - U U As 0 0 D D Hg U Conclusions As has been observed in the past three editions of the Annual Biology Report PJV 2007, PJV 2008, PJV 2009, bioaccumulation of cadmium in freshwater prawn at sites downstream of the mine in the lower Strickland River is occurring to a greater extent than at reference sites. Significantly elevated levels of cadmium were detected in the cephalothorax of M. latidactylus and in both cephalothorax and abdomen flesh samples of M. rosenbergii. Cadmium elevation was also detected in liver samples of P. macrorhynchus. The continued detection of elevated bioaccumulation of cadmium in prawn tissues in the lower Strickland River is again consistent with a persistent mine-related alteration of cadmium bioavailability. Bioaccumulation of lead in the cephalothorax of both M. rosenbergii and M. latidactylus and liver samples of P. macrorhynchus in the Strickland River has continued to occur in Arsenic was again detected at elevated levels in prawn tissues from downstream of the mine, but unlike 2007 and 2008, levels where only higher in M. rosenbergii cephalothorax and flesh at SG5 compared with both reference site samples Selenium concentrations were found to be elevated at Strickland River sites in almost all tissues types sampled. Elevated selenium was detected in samples from Tiumsinawam in the cephalothorax and flesh of M. latidactylus and the flesh of M. rosenbergii, while liver and flesh samples of P. macrorhynchus collected from Bebelubi where elevated in selenium also. Rank correlations of selenium concentrations over several years indicated a general increasing trend for

311 most tissues collected at most sites, the cause of this phenomenon is not certain but should continue to be monitored. It is hoped that the study undertaken by CSIRO will go some way to explaining this occurrence. Zinc was also found to be at elevated concentrations in all three species sampled during 2009 at Strickland River sites when compared with the reference sites Lake Murray Sites at Lake Murray were not sampled during 2009 due to landowner intervention. It is unknown whether this sampling will be allowed to occur in the future. 3.5 Comparisons with Effects Levels The measured tissue metal concentrations for 2009 were compared against the lowest observed concentration co-occurring with an effect LOEC for each tissue type and organism type fish or prawn for each metal in the effects database of Jarvinen and Ankley 1999 Table '. Table gives the results of non-reference sites where the proportion of samples found to have metal concentrations above the corresponding LOEC is greater than that found for all reference sites. Table 15 Lowest observed effect concentration for each tissue type and organism collated from Jarvinen and Ankley 1999 Fish post-larval Prawn Metal Flesh Liver Gill Whole Whole Cadmium Mercury Copper Selenium Zinc Arsenic Lead Nickel The screening of tissue metal concentrations against the LOEC values of Jarvinen and Ankley 1999 cannot be used to prove increased adverse ecological effects of metal bioaccumulation, rather it is unlikely that concentrations below the LOEC would result in detrimental effects. The patterns of increased proportions of samples above the corresponding LOECs described in this section suggest an increased potential for there being some additional risk of detrimental impact, but determining whether or not any actual detriment has occurred would require measurement of effects. Table 16 Sites where the ratio of above:below for impact sites is greater than for any reference site using the recorded tissue metal concentrations above the LOEC values of Jarvinen and Ankley Species Tissue Type Metal Sites Recorded Macrobrachium handschini Cephalothorax Cd Wasiba Neosilurus equinus Liver Cd Wankipe, Wasiba Potomosiluris macrorhynchus Liver Cd Bebelubi, Tiumsinawam Liver Hg Bebelubi, Tiumsinawam Flesh Zn Bebelubi

312 4 GENERAL CONCLUSIONS 4.1 Species Richness, Abundance and Condition In the upper catchment, there was no evidence to suggest any mine-related impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year 2009, nor in rank correlation assessments of trends over the extent of available data between 2000 and 2009 at each site except for at Wasiba where a declining trend was detected for prawn numbers and biomass from 2000 to Standardised sampling is not currently undertaken at the reference sites at Kuru River and Pori River due to the lack of suitable sandbank to perform seine netting. It is planned that during 2010 backpack electrofishing will be implemented at all upper catchment sites to increase the likelihood of achieving sample numbers for tissue collection and to give another standardised method to measure species richness, abundance, diversity and biomass. At lower Strickland River sites standardised gill and seine netting did not suggest any mine-related impacts to the species richness, diversity, abundance or biomass of fish or prawns for the year There were no unmatched decreasing trends detected at sites downstream of the mine within the time period 2000 to Hydroacoustic sampling at lower Strickland off river water bodies and Lake Murray was undertaken in In 2009, fish density at Avu was found to be significantly greater than that observed at Maka, although it is thought that this was partly an artefact of the large amount of floating macrophyte racks at Avu. For the oxbow lakes, Levame, Oxbow 3 and Zongamange, no significant differences in fish density were detected. A comparison of fish density between sampling in 2008 and 2009 at each site detected significant differences for Avu, Maka and Zongamange. At Avu and Zongamange, fish density was found to have significantly decreased in 2009 when compared with data from 2008 while at Maka fish density observed in 2009 was significantly greater than that seen in While differences have been detected, the use of hydroacoustic sampling is still in its early stages and further years of sampling will be needed for full understanding of the natural variation that would be expected to be seen at these sites. Specimen condition in the upper catchment indicated a significant difference for the prawn M. handschini at Wasiba when compared with prawns collected at Pori River, indicating a possible mine-related effect. This trend was not observed between Wasiba and the other reference sites at Ok Om or Kuru River but should be closely monitored throughout 2010 monitoring. Spearman s rank correlations indicated that there were no significant decreasing trends for N. equinus or M. handschini at sites downstream of the mine within the time period 2000 to The condition of fish and prawns at lower Strickland River sites was not found to be significantly different between sites downstream of the mine and reference sites. However, a significant decreasing trend in the condition of P. macrorhynchus collected at Tiumsinawam was detected over the time period 2000 to Tissue Metal Concentrations Quality Assurance Laboratory based quality assurance was acceptable for samples analysed in Quarters 2, 3 and 4, while laboratory duplicate samples in Quarter 1 where outside the required RPD values for arsenic, nickel, copper, chromium and mercury. The use of field blanks was a great improvement over recent years and the biological team should be commended for this effort. A total of 31 field blanks were used in 2009, a major improvement on 2008 where only seven field blanks were used. The analysis of the field blanks indicated that some contamination of samples is occurring during sample processing and possibly during sample

313 preparation at the analytical laboratory. A review of sample processing during 2010 is recommended. The results of the field blank analysis indicated that a greater margin of error should be associated with the samples analysed in 2010 and the subsequent tissue metals analysis Temporal and Spatial Variation Tissue sampling of target organisms was undertaken at all planned sites in 2009, except at Lake Murray where landowner intervention and unreasonable compensation demands prevented sampling for tissues from occurring. Sampling at sites in the Lower Strickland continued at the expanded number of sites in 2008 with both Bebelubi and the reference site at Baia River sampled for the fourth year in a row with plans to increase sampling at these sites from biannual to quarterly. The extent of mine-related and in some cases anomalous elevation of metal bioaccumulation is discussed for each metal in turn below: Cadmium: The prevalence of cadmium in tissues from prawns and fish from both the upper catchment and the lower Strickland River region has increased in All samples of prawn cephalothorax from all sites downstream of the mine were found to be significantly elevated compared with samples from all reference sites. Other tissue types that were found to contain significantly elevated concentrations of cadmium compared with all reference sites were prawn flesh at Wankipe, Wasiba and Tiumsinawam and fish liver at Bebelubi. Tissue types where sites downstream of the mine were found to have significantly elevated average cadmium concentrations when compared with at least one of the reference sites included prawn flesh at Tiumsinawam and fish liver at Wankipe and Wasiba. Increasing trends in cadmium concentrations at possible impact sites that were not matched at reference sites were also detected for a number of tissues, including fish liver at Tiumsinawam and Bebelubi over the longer term and Tiumsinawam over the shorter term and prawn flesh at Wasiba and Tiumsinawam over the shorter term. Copper: Average concentrations of copper were found to be significantly elevated in fish flesh at Tiumsinawam when compared with both reference sites while copper concentrations in prawn cephalothorax at Wasiba and Tiumsinawam were significantly higher than at least one of the reference sites and prawn flesh was found to have elevated levels of copper at Wankipe and Tiumsinawam compared with at least one reference site. Increasing trends in copper concentrations at potentially mine impacted sites that were not matched at corresponding reference sites were detected for fish flesh at Wasiba over the shorter term, at Bebelubi in prawn flesh over the longer term, at Tiumsinawam in prawn cephalothorax and fish liver over the longer term, at Bebelubi in fish flesh over the longer term and at Tiumsinawam in fish flesh over the shorter term. Lead: Zinc: Concentrations of lead were found to be significantly elevated in prawn cephalothorax at Wasiba and Wankipe when compared with all reference sites, at Wankipe in prawn flesh compared with all reference sites and fish liver at Bebelubi compared with all reference sites. Possible impact sites that were found to have significantly elevated concentrations of lead compared with at least one of the reference sites included prawn cephalothorax collected from Tiumsinawam, SG5 and Bebelubi, prawn flesh at Tiumsinawam and fish liver at Wankipe and Wasiba. There were no significant increasing trends detected at potential impact sites for lead in all tissue types over both the short and long term data available. Average concentrations of zinc were found to be significantly elevated in prawn cephalothorax at SG5 compared with all reference sites and in fish liver at Bebelubi

314 compared with all reference sites. Other potentially impacted sites that have been found to be elevated when compared with at least one of the reference sites were Tiumsinawam, SG5 and Bebelubi for prawn cephalothorax, Tiumsinawam for prawn flesh and Wankipe and Wasiba for fish liver. Increasing trends that were detected for zinc concentrations in tissues at potentially mine impacted sites that were not matched at reference sites included prawn flesh at Wasiba over the longer term, fish flesh at Wankipe over both the longer and shorter term and in prawn cephalothorax, fish flesh and fish liver at Tiumsinawam over the longer term Selenium: Selenium concentrations that were found to be significantly elevated at potentially impacted sites compared with all reference sites included prawn flesh at Tiumsinawam, fish liver at Bebelubi and fish flesh at Wasiba and Bebelubi. Other sites that were found to have significantly elevated concentrations of selenium compared with at least one of the reference sites included Wasiba, Wankipe and SG5 for prawn flesh, Wasiba for fish liver and Wankipe for fish flesh. Increasing trends that were detected at sites downstream of the mine that weren t matched at reference sites included fish flesh at Wankipe, Tiumsinawam and Bebelubi over the longer term, prawn flesh at Tiumsinawam and SG5 over the shorter term, prawn cephalothorax at Tiumsinawam and Bebelubi over the longer term and at Tiumsinawam for fish liver over the longer term. Selenium was found to be increasing for a number of tissue types at both reference and impact sites in the upper catchment and the lower Strickland River region Arsenic: Mercury: Nickel: Average concentrations of arsenic were found to be significantly elevated in prawn cephalothorax at Wasiba, Wankipe and SG5 and prawn flesh at SG5 compared with all reference sites. Significant increasing trends at sites downstream of the mine that were not matched by reference sites were observed at Wasiba for prawn cephalothorax and flesh over the long term, at SG5 for prawn cephalothorax over the shorter term and at Tiumsinawam and Bebelubi for fish liver over the longer term. Average concentrations of mercury were found to be elevated at the impacted site Bebelubi for both fish liver and flesh when compared with all reference sites. Significant increasing trends for mercury concentrations at impacted sites that were not matched at reference sites included prawn cephalothorax at Wasiba over the short term, prawn cephalothorax at Tiumsinawam over the longer term and fish flesh at Bebelubi over the longer term. Concentrations of nickel that were observed to be significantly elevated at impact sites compared with at least one reference sites included Tiumsinawam and SG5 for prawn cephalothorax samples. Significant increasing trends observed at impacted sites that were not matched at reference sites occurred at Tiumsinawam for prawn cephalothorax over the longer term and at Tiumsinawam for prawn flesh over the shorter term. The results of tissue metals analysis for samples collected in 2009 indicated that the patterns of elevation of metal bioaccumulation in the Lagaip River and the lower Strickland River region reported in previous editions of the Annual Biology Report has persisted. Significantly elevated levels of cadmium and lead have continued to be detected in prawn cephalothorax right down to SG5. For cadmium this pattern has remained in samples. Overall, these results demonstrated the persistence of the patterns of elevation and of metal bioaccumulation in the Lagaip River that had been reported previously and that the elevation of bioaccumulation of cadmium has continued to be widespread in the lower Strickland. Elevated bioavailability of arsenic was observed as far down the river system as SG5 in both prawn cephalothorax and flesh samples, while for mercury this was observed in both fish flesh and liver only at Bebelubi in the lower Strickland. While an increase in the prevalence of some metals and metalloids throughout the catchment can be inferred from the tissue metal concentration results, the contamination that was detected in the field blank samples needs to be taken into consideration. Concentrations of copper, zinc, selenium

315 and mercury were found to be outside the acceptable quality assurance limits of the field blanks from each quarter. Therefore, the interpretation of the results needs to make allowance for this increased margin of error. Taking this into account the results of the tissue metals analysis were very similar to the results from 2007 and The results of the tissue metal concentrations for each tissue type and organism type were screened against the lowest observed concentration co-occurring with an effect LOEC from the effects database of Jarvinen and Ankley Sites where the ratio of results above:below the corresponding effects threshold for impact sites was found to be greater than for any of the corresponding reference sites where found at all impacted sites down to Tiumsinawam for cadmium in prawn cephalothorax and fish liver and also for mercury in fish liver and zinc in fish flesh. The use of literature LOEC values as a screening tool for the risk of adverse biological consequences of the observed patterns of metal bioaccumulation suggests that it was not possible to conclude that there was little risk of adverse consequences at least, as far downstream as the Strickland River at Tiumsinawam. However, this approach is at best an initial screen of potential risk and cannot be used to conclude that there is increased risk. A dedicated effort to collect prawns from the upper catchment for serum sorbitol dehydrogenase enzyme marker analysis was undertaken in the 3 rd quarter of Samples were collected from the impacted sites in the Lagaip River at Wasiba and Wankipe and at the reference sites at Ok Om and Pori River. The results of the analysis on the prawn abdomen indicated significantly p=0.001 elevated hepatic cell damage in prawns collected from Wasiba and Wankipe when compared with prawns from the reference sites. This result is similar to that detected in 2006 where prawns from the impacted sites at Wasiba and Wankipe where observed to have increased levels of SDH compared with reference sites. It is not known whether the amount of hepatic cell damage reflected by these increased levels of SDH are tolerable by the prawn species sampled. Investigations into the relationship between these levels of SDH in the prawn abdomen and organism health would allow for a better understanding of the state of the population in the upper catchment. During 2010 the continuation of the SDH program in the upper catchment and the inclusion of sites in the lower Strickland region will further enhance the biological biomonitoring programs power to detect impacts at the population level before detrimental damage at the population level occurs. During 2009 a PhD project commenced with the aim to investigate the mechanisms for elevation of bioavailability of metals in the lower Strickland region. The project, run in partnership with CSIRO and Hydrobiology, will attempt to form an understanding of the nature of the bioavailable fractions, and whether or not this can be managed. 5 RECOMMENDATIONS Implement electrofishing sampling at upper catchment and lower Strickland region sites to enhance the current methods used to monitor catch and to ensure adequate prawn samples are collected for tissue and SDH analysis; Continue to investigate and negotiate with landowners in the Nomad and Rentoul River systems to establish one more reference site in the lower Strickland region; Continue to increase the use of field blank samples and ensure the cleanliness of the biology laboratory when processing samples to limit the chance of contamination; Continue SDH analysis of upper catchment prawns as well as expanding the program to include prawns from the lower Strickland region;

316 Implement a program to benchmark the effect levels of the elevated bioavailability of metals to the prawns in the upper catchment in terms of the observed SDH and the impacts this may be having on the biological processes of the organisms; Consider other sub-organism and organisms level effect markers in areas where SDH analyses demonstrate increased hepatic cell loss rates. Such markers could include histopathological examination of selected tissues and markers of fecundity, such as the gonado-somatic index. Development of this approach could be done in collaboration with the existing research being conducted jointly with CSIRO and Hydrobiology; Implement seine netting at SG5 and trial fyke nets in an effort to increase prawn catches.

317 6 REFERENCES ANZECC/ARMCANZ Australia and New Zealand Environment and Conservation Council/Agriculture and Resource Management Council of Australia and New Zealand 2000a. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Agriculture and Resource Management Council of Australia and New Zealand: Canberra. Bunn, S.E., Apte, S.C., Bentley, K., Hart, B.T. and Smith, R.E.W Porgera Riverine Monitoring Program Review and Optimisation. Porgera Joint Venture. Fujino et al Bulletin of the Japanese Society of Scientific Fisheries 46: Hydrobiology An ecological assessment of the aquatic and terrestrial habitats of the Willawong remediation site. Hydrobiology Pty Ltd, Brisbane. Hydrobiology 2005a. Lane Xang Minerals Limited Aquatic Biomonitoring Report. Wet Season Hydrobiology Pty Ltd, Brisbane. Hydrobiology 2005b. Lane Xang Minerals Limited Aquatic Biomonitoring Report. Dry Season Hydrobiology Pty Ltd, Brisbane. Hydrobiology 2005c. A biological assessment of Oxley and Blunder Creeks. Hydrobiology Pty Ltd, Brisbane. Insightful Inc S-Plus 6.2 for Windows Insightful Inc, Seattle. Jarvinen A. W. and Ankley G. T Linkage of Effects to Tissue Residues: Development of a Comprehensive Database for Aquatic Organisms Exposed to Inorganic and Organic Chemicals. SETAC Press, Pensacola. Lang, R Enzyme der Monosaccharidumwandlung bei dem Flußkrebs Orconectes limosus. J. Comparat. Physiol. A. 733: Porgera Joint Venture 2003 PJV Environmental Monitoring 2002 Annual Report January- December PJV/ENV-1/03. Porgera Joint Venture 2004 Porgera Joint Venture Biological Monitoring Technical Report 1 January 31 December PJV/ENV-2/04. Porgera Joint Venture 2004b Sustainable Development Dept Environment Section Biology Procedures Manual. Controlled document, Version 1.1, Release Date Feb Porgera Joint Venture 2005 Biological Monitoring Technical Report. 01 January 31 December PJV/ENV-2/05 Porgera Joint Venture 2006 Biological Monitoring Technical Report. 01 January 31 December PJV/ENV-2/06 Porgera Joint Venture 2007 Biological Monitoring Technical Report. 01 January 31 December PJV/ENV2/07 Porgera Joint Venture 2008 Biological Monitoring Technical Report. 01 January 31 December PJV/ENV-2/08 Travlos GS, Morris RW, Elwell MR, Duke A, Rosenblum S & Thompson MB Frequency and relationships of clinical chemistry and liver and kidney histopathology findings in 13-week toxicity studies in rats. Toxicol 107:

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319 Kuru Kuru Kuru Pori Pori Pori Ok Om Ok Om Ok Om Wasiba Wankipe Wasiba Wankipe Wasiba Wankipe Kuru Pori Ok Om 4 3 Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Wasiba Wankipe Kuru Pori Ok Om Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] 20 Wasiba Wankipe Ok Om Pori Kuru Wasiba Wankipe Kuru Pori Ok Om Se [mg/kg] As [mg/kg] Hg [mg/kg] 1.0 Wasiba Wankipe Ok Om Pori Kuru Wasiba Wankipe 0.0 Macrobrachium handschini - cephalothorax Black line - detection limits

320 Kuru Kuru Kuru Pori Pori Pori Ok Om Ok Om Ok Om Wasiba Wankipe Wasiba Wankipe Wasiba Wankipe Kuru Pori Ok Om Wasiba Wankipe Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] 4 2 Wasiba Wankipe Ok Om Pori Kuru Kuru Pori Ok Om Wasiba Wankipe Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] 5 Wasiba Wankipe Ok Om Pori Kuru Kuru Pori Ok Om Wasiba Wankipe 0.8 Se [mg/kg] As [mg/kg] Hg [mg/kg] Wasiba Wankipe Ok Om Pori Kuru 0.0 Macrobrachium handschini - flesh Black line - detection limits

321 Kuru Kuru Kuru Pori Pori Pori Ok Om Ok Om Ok Om Wasiba Wankipe Wasiba Wankipe Wasiba Wankipe Kuru Pori Ok Om Wasiba Wankipe Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Kuru Pori Ok Om Wasiba Wankipe Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] Wasiba Wankipe Ok Om Pori Kuru Kuru Pori Ok Om Wasiba Wankipe Se [mg/kg] As [mg/kg] Hg [mg/kg] Wasiba Wankipe Ok Om Pori Kuru 0 Neosilurus equinus - liver Black line - detection limits

322 Kuru Kuru Kuru Pori Pori Pori Ok Om Ok Om Ok Om Wasiba Wankipe Wasiba Wankipe Wasiba Wankipe Kuru Pori Ok Om Wasiba Wankipe Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] 0.1 Wasiba Wankipe Ok Om Pori Kuru Kuru Pori Ok Om Wasiba Wankipe Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] 4 2 Wasiba Wankipe Ok Om Pori Kuru Kuru Pori Ok Om Wasiba Wankipe Se [mg/kg] As [mg/kg] Hg [mg/kg] Wasiba Wankipe Ok Om Pori Kuru 0.0 Neosilurus equinus - flesh Black line - detection limits

323 Baia Baia Baia Tomu Tomu Tomu SG5 SG5 SG5 Bebelubi Tiumsinawam Bebelubi Tiumsinawam Bebelubi Tiumsinawam Baia Tomu SG5 Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] Bebelubi Tiumsinawam Baia Tomu SG5 SG5 Tomu Baia Bebelubi Tiumsinawam Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia Bebelubi Tiumsinawam Baia Tomu SG Se [mg/kg] As [mg/kg] Hg [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia Bebelubi Tiumsinawam 0.0 Macrobrachium rosenbergii - cephalothorax Black line - detection limits

324 Baia Baia Baia Tomu Tomu Tomu SG5 SG5 SG5 Bebelubi Tiumsinawam Bebelubi Tiumsinawam Bebelubi Tiumsinawam Baia Tomu SG5 Bebelubi Tiumsinawam Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] Bebelubi Tiumsinawam SG5 Tomu Baia Baia Tomu SG5 Bebelubi Tiumsinawam Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] 5 Bebelubi Tiumsinawam SG5 Tomu Baia Baia Tomu SG5 Bebelubi Tiumsinawam Se [mg/kg] As [mg/kg] Hg [mg/kg] 0.1 Bebelubi Tiumsinawam SG5 Tomu Baia 0.0 Macrobrachium rosenbergii - flesh Black line - detection limits

325 Baia Baia Baia Tomu Tomu Tomu Bebelubi Tiumsinawam Bebelubi Tiumsinawam Bebelubi Tiumsinawam Baia Tomu 0.6 Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] 10 Bebelubi Tiumsinawam Tomu Baia Bebelubi Tiumsinawam Baia Tomu 0.7 Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] 20 Bebelubi Tiumsinawam Tomu Baia Bebelubi Tiumsinawam Baia Tomu Se [mg/kg] As [mg/kg] Hg [mg/kg] Bebelubi Tiumsinawam Tomu Baia Bebelubi Tiumsinawam 0.0 Macrobrachium latidactylus - cephalothorax Black line - detection limits

326 Baia Baia Baia Tomu Tomu Tomu Bebelubi Tiumsinawam Bebelubi Tiumsinawam Bebelubi Tiumsinawam Baia Tomu Bebelubi Tiumsinawam Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] 4 2 Bebelubi Tiumsinawam Tomu Baia Baia Tomu Bebelubi Tiumsinawam Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] 5 Bebelubi Tiumsinawam Tomu Baia Baia Tomu Bebelubi Tiumsinawam Se [mg/kg] As [mg/kg] Hg [mg/kg] 0.1 Bebelubi Tiumsinawam Tomu Baia 0.0 Macrobrachium latidactylus - flesh Black line - detection limits

327 Baia Baia Baia Tomu Tomu Tomu Bebelubi Tiumsinawam Bebelubi Tiumsinawam Bebelubi Tiumsinawam Baia Tomu Bebelubi Tiumsinawam 12 8 Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] Bebelubi Tiumsinawam Tomu Baia Baia Tomu Bebelubi Tiumsinawam Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] Baia Tomu Bebelubi Tiumsinawam Bebelubi Tiumsinawam Tomu Baia Se [mg/kg] As [mg/kg] Hg [mg/kg] Bebelubi Tiumsinawam Tomu Baia 0 Potamosilurus macrorhynchus - liver Black line - detection limits

328 Baia Baia Baia Tomu Tomu Tomu Bebelubi Tiumsinawam Bebelubi Tiumsinawam Bebelubi Tiumsinawam Baia Tomu Bebelubi Tiumsinawam Cu [mg/kg] Cd [mg/kg] Pb [mg/kg] Bebelubi Tiumsinawam Tomu Baia Baia Tomu Bebelubi Tiumsinawam Zn [mg/kg] Cr [mg/kg] Ni [mg/kg] 5 Bebelubi Tiumsinawam Tomu Baia Baia Tomu Bebelubi Tiumsinawam Se [mg/kg] As [mg/kg] Hg [mg/kg] Bebelubi Tiumsinawam Tomu Baia 0.0 Potamosilurus macrorhynchus - flesh Black line - detection limits

329

330 Upper Catchment 3 7 B 0 6: 7& 9 9 ;;4 Metal Factor Multiple Comparisons Cu Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Site:Length Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logcu.wet Cd Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logcd.wet Pb Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logpb.wet

331 Metal Factor As Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Multiple Comparisons Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba Zn Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Site:Length Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-009 Length e-011 Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logas.wet simultaneous 95 % confidence limits, Tukey method response variable: logzn.wet simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

332 3 7 B0 6: 7& ;;4 Metal Factor Multiple Comparisons Cu Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logcu.wet Cd Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logcd.wet Pb Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-007 Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logpb.wet

333 Metal Factor Zn Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Multiple Comparisons Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logzn.wet Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

334 3 7 B0 6: 7 99 ;;4 Metal Factor Multiple Comparisons Cd Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-007 Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logcd.wet Pb Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logpb.wet Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

335 3 7 B0 6: ;;4 Metal Factor Multiple Comparisons Zn Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logzn.wet Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-010 Length e-006 Residuals Kuru-Ok Om Kuru-Pori Kuru-Wankipe Kuru-Wasiba Ok Om-Pori Ok Om-Wankipe Ok Om-Wasiba Pori-Wankipe Pori-Wasiba Wankipe-Wasiba simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

336 Lower Strickland 3 7 B0 6: 77& & 9 9 ;;4 Metal Factor Multiple Comparisons Cd Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Site:Length Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG5 Pb Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-007 Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG simultaneous 95 % confidence limits, Tukey method response variable: logcd.wet simultaneous 95 % confidence limits, Tukey method response variable: logpb.wet As Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-008 Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG simultaneous 95 % confidence limits, Tukey method response variable: logas.wet

337 Metal Factor Zn Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Multiple Comparisons Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG simultaneous 95 % confidence limits, Tukey method response variable: logzn.wet Ni Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-007 Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG simultaneous 95 % confidence limits, Tukey method response variable: logni.wet

338 3 7 B0 6: 77& & ;;4 Metal Factor Multiple Comparisons Cu Baia-Bebelubi Type III Sum of Squares Baia-Tiumsinawam Df Sum of Sq Mean Sq F Value PrF Baia-Tomu Baia-SG5 Site Bebelubi-Tiumsinawam Bebelubi-Tomu Length Bebelubi-SG5 Site:Length Tiumsinawam-Tomu Tiumsinawam-SG5 Residuals Tomu-SG5 Cd As Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site e-006 Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG5 Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG5 Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Baia-SG5 Bebelubi-Tiumsinawam Bebelubi-Tomu Bebelubi-SG5 Tiumsinawam-Tomu Tiumsinawam-SG5 Tomu-SG simultaneous 95 % confidence limits, Tukey method response variable: logcu.wet simultaneous 95 % confidence limits, Tukey method response variable: logcd.wet simultaneous 95 % confidence limits, Tukey method response variable: logas.wet simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

339 3 7 B0 6: 77& 9 9 ;;4 Metal Factor Multiple Comparisons Cu Baia-Bebelubi Type III Sum of Squares Baia-Tiumsinawam Df Sum of Sq Mean Sq F Value PrF Baia-Tomu Bebelubi-Tiumsinawam Site Bebelubi-Tomu Tiumsinawam-Tomu Residuals Cd Pb Zn Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Site:Length Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu simultaneous 95 % confidence limits, Tukey method response variable: logcu.wet simultaneous 95 % confidence limits, Tukey method response variable: logcd.wet simultaneous 95 % confidence limits, Tukey method response variable: logpb.wet simultaneous 95 % confidence limits, Tukey method response variable: logzn.wet simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

340 3 7 B0 6: 77& ;;4 Metal Factor Multiple Comparisons Cu Baia-Bebelubi Type III Sum of Squares Baia-Tiumsinawam Df Sum of Sq Mean Sq F Value PrF Baia-Tomu Bebelubi-Tiumsinawam Site Bebelubi-Tomu Tiumsinawam-Tomu Residuals Cd Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu simultaneous 95 % confidence limits, Tukey method response variable: logcu.wet simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

341 3 7 B0 6: ;;4 Metal Factor Multiple Comparisons Cd Type III Sum of Squares Baia-Bebelubi Df Sum of Sq Mean Sq F Value PrF Baia-Tiumsinawam Baia-Tomu Site Bebelubi-Tiumsinawam Bebelubi-Tomu Length Tiumsinawam-Tomu Residuals Pb Hg Zn Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Residuals Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu simultaneous 95 % confidence limits, Tukey method response variable: logcd.wet simultaneous 95 % confidence limits, Tukey method response variable: logpb.wet simultaneous 95 % confidence limits, Tukey method response variable: loghg.wet simultaneous 95 % confidence limits, Tukey method response variable: logzn.wet simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

342 3 7 B0 6: ;;4 Metal Factor Multiple Comparisons Zn Type III Sum of Squares Baia-Bebelubi Df Sum of Sq Mean Sq F Value PrF Baia-Tiumsinawam Baia-Tomu Site e-010 Bebelubi-Tiumsinawam Bebelubi-Tomu Length e-013 Tiumsinawam-Tomu Residuals Se Type III Sum of Squares Df Sum of Sq Mean Sq F Value PrF Site Length Residuals Baia-Bebelubi Baia-Tiumsinawam Baia-Tomu Bebelubi-Tiumsinawam Bebelubi-Tomu Tiumsinawam-Tomu simultaneous 95 % confidence limits, Tukey method response variable: loghg.wet simultaneous 95 % confidence limits, Tukey method response variable: logse.wet

343 "#%&'

344 "#" % SORBITOL DEHYDROGENASE SDH IN PRAWN TAILS, 2009 Introduction In the liver of vertebrates, the enzyme sorbitol dehydrogenase SDH performs the metabolism of fructose into sorbitol. Normally, SDH is contained into the cytoplasm of hepatocytes, and its concentration is negligible in the bloodstream. When necrosis of the hepatocytes occur, the content of the cytoplasm is released into the bloodstream and SDH might be at this point detectlable in the bloodstream Ozetric and Krajnovic-Ozetric, Consequently, SDH activity is a biomarker of biologically relevant effect. The livers of organisms that have experienced cellular injuries related to xenobiotic exposure are less capable of performing metabolic activities Holdway et al SDH activity is not affected by conditions such as reproductive status which often are confounding factors in the interpretation of other biomarkers. Most invertebrates do not have a well defined liver but instead, have an hepatopancreas which functions much as a liver. Invertebrates such as prawns are highly vulnerable to hepatocellular injury related to xenobiotic exposure, especially exposure to metals. Previous studies have shown that while SDH activity is detectable in the hepatopancreas of prawns, the activity of this enzyme in the tail flesh is able to discriminate better the exposure history of the organism. SDH activity has been determined in related invertebrates such as the crayfish Orconectes limosus [Lang R., Z. Vgl. Physiol. 73: ] and abalone Haliotis discus [Fujino et al. Bull. Japan. Soc. Fis. 46: ]. Procedures Thirty-eight 38 prawn tails have been received frozen on dry ice. The tissues were thawed slowly, and homogenized with Trizma / EDTA physiological buffer that was supplemented with phenylmethylsulfonyl fluoride PMSF as a protease inhibitor. Following high speed centrifugation under refrigerated conditions, the supernatant was isolated and used immediately for the SDH assay. SDH activity was measured by following the rate of decrease in absorbance A over one minute at 340 nm on a spectrophotometer, using the kinetic continuous reading of the cuvette absorbance. The enzymatic activity is reported in milli-international Unit mu per gram of tissue. One International Unit U of an enzyme is defined as the amount which will convert 1M of substrate into product per minute in this case, fructose is converted to sorbitol. Statistical analysis The study comprised two reference sites Ok Om and Pori and two exposed sites Wankipe and Wasiba. All data were log-transformed to comply with the assumptions of normality and homoscedasticity. Initially, the two reference sites were compared using a t-test, which confirmed that the two reference sites were statistically similar. The data from the two sites were therefore pooled to compare to the two exposed sites. The pooling of the two reference sites provides a better statistical power to establish differences between reference and exposed locations. A one-way ANOVA, with origin as a classification factor, was performed on the logtransformed data using Dunnett as a post-hoc test. The advantage of using the Dunnett test is that is allows for the identification of a reference group to which all other groups are compared, providing a better discriminatory power. The statistical analysis has been performed on SPSS version 17.0, at α = 0.05 after. Details of statistical results are provided in Appendix 1.

345 "#" % Prawn SDH activity results The SDH activity, according to the location where prawns were collected, is described in Table 1. ** &+,* %&* # -, &. *# %& /,± "'± % 3 7 ; 2;±2 8 ; ""±'+ 8 ; "±"+ The prawns sampled at Ok Om and at Pori had statistically similar SDH activity in their tissue p = The data from these two sites were combined in order to compare the SDH activity observed under reference conditions to the SDH activity at the exposed sites. SDH activity observed at Wankipe was found to be statistically higher p < than at the reference sites. Similarly, the SDH activity in prawn collected at Wasiba was higher than that of the reference sites p = SDH activity in prawn tails SDH Activity mu/g tissue Ok Om Pori Wankipe Wasiba ORIGIN 2,%&/* 34,+ 1#5 + * 6+++* /*1 +

346 "#" % The observed SDH activity in the prawns collected in 2009 at Ok Om, Wankipe and Wasiba follows similar trends to the SDH activity previously observed in prawn flesh from these locations. If considered on a unit basis i.e. in mu per gram of flesh, the SDH activity is slightly lower in the 2009 prawns compared to the previously collected 2006 prawns. This might be due to the time of the year where collection took place, rather than changes in the bioavailable contaminants, since the SDH activity at the reference site is also slightly reduced.

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