ORICA VILLAWOOD ONGOING GROUNDWATER MONITORING. December Orica Australia Pty Ltd. Revision 1

Transcription

1 ORICA VILLAWOOD ONGOING GROUNDWATER MONITORING December 2010 Orica Australia Pty Ltd Revision 1 Groundwater Monitoring Plan 1 6 December 2010

2 1 INTRODUCTION SITE DESCRIPTION AND HISTORY PREVIOUS INVESTIGATIONS ASSESSMENT CRITERIA PROJECT OBJECTIVES PROJECT SCOPE GROUNDWATER SAMPLING AND ANALYSIS... 7 Groundwater Monitoring Plan 2 6 December 2010

3 1 INTRODUCTION Orica Australia Pty Ltd (Orica) is required to undertake ongoing groundwater monitoring at the Orica Villawood Site to meet the requirements of Remediation Order (RO) No 23019, Area 3200, issued by the NSW Environment Protection Authority on 2 November Site Description and History Item Details Site Owner Orica Australia Pty Limited Site Address 2 Christina Road, Villawood, NSW 2163 Lot and DP Numbers Lot 1 in Deposited Plan (DP) City, County and Parish Local Government Authority Site Area City of Bankstown, Parish of Liberty Plains, County of Cumberland Bankstown City Council Approximately 12.6 hectares (ha) The Site was initially part of a larger chemical manufacturing complex owned by the Commonwealth of Australia and was used for the manufacturing of munitions, including trinitrotoluene (TNT), during World War II. The Site was subsequently purchased by Taubmans in 1946, who manufactured a range of chemicals including (mono) chlorobenzene (MCB) and DDT (degradation products of which include DDD and DDE) until the southern portion of the Site was purchased by Imperial Chemical Industries of Australia and New Zealand Pty Limited (ICIANZ) in ICIANZ (and later Orica) continued to manufacture a wide range of agricultural and pharmaceutical chemicals on the Site until its closure in The geology in the vicinity of the Site comprises four principle elements; fill materials, residual clay on-site, alluvial clay off-site and basal Bringelly Shale. The uppermost unit on-site and off-site comprises fill material of reworked clay. Residual clay on-site is likely to be weathered Bringelly Shale which is mottled orange/grey, moist and has moderate to high plasticity. Highly weathered shale underlies the Site at depths greater than 1 metre. 1.2 Previous Investigations Groundwater has been monitored at the site since 2000 in a number of field investigations. The majority of wells installed across the Site and in off-site areas intersect the shallow portion of the aquifer. The water table elevation reflects the regional and local topography and indicates that groundwater in the northern and western portion of the Site flows in a westerly direction. Groundwater from the southern and eastern portion of the Site generally flows in a south-westerly direction towards the Byrnes Creek concrete lined channel. A number of investigations pertaining to the contamination status of the Site have been completed. These include: Groundwater Monitoring Plan 3 6 December 2010

4 A.D. Laase Hydrologic Consulting, June Groundwater Flow and Contaminant Transport Modelling; URS, Human Health and Environmental Risk Assessment (HHERA), Orica Villawood site, 22 June Ref ; and HLA ENSR, 2010, Remedial Action Plan, 2 Christina Road, Villawood. Report S _Final_RAP_Dec10. AECOM, RAP Addendum, 2 Christina Road, Villawood. Report S _Final_RAP_9July09. AECOM, Round 1 Groundwater Monitoring Event, 2 Christina Road, Villawood. Report S41070_RPT_Draft_29Oct09. AECOM, Round 2 Groundwater Monitoring Event, 2 Christina Road, Villawood. Report S41418_Draft_RPT_27July210. A summary of the nature and extent of soil and groundwater contamination are contained within the RAP (HLA ENSR, 2010). 1.3 Assessment Criteria The HHERA for the site (URS 2010) provide a summary of the RBGCs derived for the off-site areas. RBGCs have been derived for COPC identified in off-site groundwater. The calculated risks from the RBGCs meet the target risk levels defined above for both long-term on-site workers and intrusive workers. The RBGC for off site areas are as follows: COPC Calculated RBGC (mg/l) hexachlorobenzene (HCB) ,2-dichloroethane (EDC) 120 vinyl chloride 6 chloroform 100 trichloroethene (TCE) 200 tetrachloroethene (PCE) 30 1,1,2-trichloroethane 3.5 chlorobenzene 200 benzene 50 toluene 6 a-hch (a-bhc) 44 b-hch (b-bhc) 0.11 d-hch (d-bhc) 0.11 g-hch (g-bhc or lindane) 16 Dieldrin 0.33 DDX (sum of DDT, DDE and DD 0.3 Groundwater Monitoring Plan 4 6 December 2010

5 Groundwater analytical results obtained during the investigation will also be assessed against the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC, 2000), which provides trigger values for chemicals within water. Trigger levels represent the best current estimates of the concentrations of chemicals that should have no significant effects on the aquatic ecosystem. Given the proximity of the Byrnes Creek channel (which is likely to discharge relatively fresh surface water runoff), groundwater results are compared to the Trigger Levels for Fresh Waters. Trigger levels with a 95% level of species protection are adopted. The ANZECC 2000 trigger values indicate that an exceedence of a trigger value does not necessarily indicate that there is an inherent risk; rather that further assessment and monitoring may be required prior to implementing appropriate management actions. Where high reliability guideline trigger values (95%) are not available, the low reliability trigger levels will be used. 2 PROJECT OBJECTIVES The objectives of the groundwater monitoring are to assess: Groundwater quality on- and off-site to ensure acceptable risk to workers in on- and off-site areas, and to confirm the findings of the groundwater modelling (A.D. Laase Hydrologic Consulting, June 2007). Groundwater elevations on- and off-site to ensure the conceptual hydrogeological model remains valid for the Site; Groundwater quality on- and off-site to ensure acceptable risk to aquatic ecosystems (Byrnes Creek concrete channel); and Groundwater quality to ensure that the spatial extent and maximum contaminant concentrations in source areas and the perimeter of the plumes remain stable or decrease. 3 PROJECT SCOPE The scope of works for the monitoring program is as follows: Activity/Item Monitoring Frequency and Duration Standing Water Level Measurement (all wells listed) Groundwater Sampling and Analysis Details Sampling is to occur annually prior to remediation (2011) and twice in the first year following completion of the remedial action. Monitoring will then be undertaken annually for a minimum period of 3 years. In the event that groundwater water table levels are reported to change significantly during the monitoring program, the frequency of monitoring events may need to be modified to assess for any related changes to the fate and transport of CoC at the Site. On Site Wells - MW13, MW14, MW15, MW16, MW17, MW18, MW19, MW20, MW21, MW22, MW25, MW26, MW27, MW28, MW30, MW31, MW32, MW33, MW34, MW35, MW36, MW37, MW38, MW39, MW40, MW41, MW42, MW43A/B/C, MW44A/B/C, MW45, MW46A/B/C, MW47, MW48, MW49, MW50, MW51, MW52, MW53A/B/C, MW77, and MW78. Off Site Wells - OS01A/B, OS03A/B; OS04A, OS05A, OS06A/B/C, OS07A/B, OS08, MW301, MW303, and MW304. As per Section 3.1 Groundwater Monitoring Plan 5 6 December 2010

6 Activity/Item Monitoring Parameters Details Monitoring will include the following: Groundwater depth (converted to metres Australian Height Datum, m AHD); and Field parameters (including temperature, electrical conductivity, ph, dissolved oxygen and redox potential). Laboratory Analysis for the following (as per Section 3.1): VHCs and s (ultra trace). Well Gauging Well Surveying Well Purging and Sampling Process Decontamination Procedure Monitoring wells will be gauged using a calibrated water level probe. The probe will be decontaminated between each measurement. Water levels will be gauged from the surveyed point on the casing. Details of the gauging dates and depths recorded will be provided as part of reporting requirements. If monitoring well heads change, a licensed surveyor will be engaged to resurvey the location and elevation of groundwater monitoring wells to mahd. All groundwater monitoring wells will be purged using low flow (such as Micropurge) pumping prior to sampling, using new disposable low-density polyethylene (LDPE) bladders, in conjunction with flow cells as necessary and dedicated LDPE tubing. Measurement of field water parameters will be conducted continuously and purging continued until groundwater field quality parameters have stabilised. Monitoring and sampling equipment will be decontaminated according to the following procedure: Wash with Decon 90 or similar decontaminant / water solution and rinse. Triple wash with laboratory supplied clean deionised water. Sample Method and Preservation Disposal of Purged Groundwater Analytical Laboratories Quality Assurance / Quality Control (QA/QC) Following stabilisation of field parameters, samples will be placed into laboratory-supplied bottles containing appropriate preservatives for the selected analytical testing. Samples will be immediately chilled and stored at a temperature of 4 C or less prior to transit to the laboratory. Purged groundwater will be disposed off-site to a licensed waste receiving facility. Purged groundwater may be placed in drums for temporary storage in an on-site, dedicated area. ALS has undertaken analysis on this site previously and Orica s preference is to remain consistent and use ALS as the primary laboratory. The secondary laboratory will also be accredited by NATA for the analyses undertaken. QA/QC samples collected for quality control purposes during each round of groundwater sampling will include the following: One intra-laboratory (same laboratory as primary samples) field duplicate; One inter-laboratory (different laboratory as primary samples) field triplicate; and One equipment rinsate blank per day. Discussion of the laboratory and field quality assurance/quality control and analytical data validation will be included in the reporting requirements. Sample Nomenclature Assessment Criteria Sample nomenclature will be consistent with the previous monitoring well nomenclature. Groundwater assessment criteria are to be consistent with the Risk-Based Groundwater Concentrations (RBGC) derived from the HHERA (URS 2010). See Section 1.3 Groundwater Monitoring Plan 6 6 December 2010

7 Activity/Item Details Data Reporting All data to be loaded into an appropriate database. A report will be prepared as per the project program (Section 4). The report will include the following: Details of groundwater monitoring program methodology and scope of works; Construction details and logs of any new or replaced groundwater monitoring wells; Results of groundwater monitoring well levels, field parameters and laboratory analysis, including NATA certified laboratory reports and chain of custody records; Comment on laboratory and field quality assurance / quality control program and analytical data validation; Comparison of groundwater data to historical groundwater concentrations (tabulated) and trend analysis; Interpretation of the data, including quality of groundwater with respect to the relevant RBGCs and interpretation of groundwater elevation contours; and Conclusions and recommendations. Documentation will be supported by figures produced using GIS. 3.1 Groundwater Sampling and Analysis Groundwater sampling will be undertaken at 18 well locations, including five multi level bundle piezometers and two dual level piezometers, at both on-site and off-site areas as shown on Figure F5 (attached). Groundwater samples will be submitted to a National Association of Testing Authorities (NATA) accredited laboratory for the following analysis (as indicated in the table below): Standard VHC analysis 31 samples (including 3 QA/QC samples); Standard analysis - 8 samples (including 1 QA/QC sample); and Ultra-trace analysis - 13 samples (including 2 QA/QC sample) The rationale for the selection of monitoring wells and analyses at each location are as follows: Proposed Monitoring Location BP Sampling Ports Site Area and Groundwater Plume Analysis Rationale for Monitoring BP106 8 & 10 m Onsite Plume 1 BP208 6 & 8 m Onsite Plume 2 MW27 - On-site Plumes 1 and 2 MW46A - On-site Plume 3 VHC and VHC and VHC and VHC and Near source of plume monitor CoPC Near source of plume monitor CoPC Near western perimeter of plumes monitor groundwater levels and CoPC Near source of plume monitor groundwater levels and CoPC Groundwater Monitoring Plan 7 6 December 2010

8 Proposed Monitoring Location BP Sampling Ports Site Area and Groundwater Plume Analysis Rationale for Monitoring MW48 - On-site Plume 4 VHC Near source of plume monitor groundwater levels and CoPC MW77 - On-site Plume 4 VHC Outside southern perimeter of plume monitor groundwater levels and CoPC BP , 5.8 & 7.8 m On-site Plume 1 VHC Near source of plume monitor CoPC OS03A/B (two wells) - Off-site Plumes 1 and 2 Within plumes monitor groundwater levels and CoPC OS05A - Off-site Plumes 1 and 2 OS10A - Off-site Plumes 1 and 2 OS08 - Off-site Plume 1 VHC VHC Within plumes monitor groundwater levels and CoPC Within plumes monitor groundwater levels and CoPC Within plume near southern perimeter monitor groundwater levels and CoPC BP108 2, 6 & 10 m Off-site Plume 1 and 2 Beyond south-western perimeter of plumes monitor CoPC BP , 9.5 & 13.5 m Off-site Plume 1 VHC Beyond southern perimeter of plume monitor CoPC MW301 - Off-site Plumes 1 and 2 MW303 - Off-site Plume 3 MW304 - Off-site Plume 3 Beyond south-western perimeter of plumes monitor CoPC Beyond Southern perimeter of plume - monitor groundwater levels and CoPC South-western perimeter of plume- monitor groundwater levels and CoPC OS07A/B (two wells) - Off-site Plume 3 North-western perimeter of plume- monitor groundwater levels and CoPC MW24 - Off-site Plume 3 VHC and Centre of plume- monitor groundwater levels and CoPC Attachments: Figure F5 Groundwater Monitoring Well Locations Groundwater Monitoring Plan 8 6 December 2010

9 Figures Groundwater Monitoring Plan 9 6 December 2010

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