8.0 WATER QUALITY 8.1 INTRODUCTION

Transcription

1 8.0 WATER QUALITY 8.1 INTRODUCTION This chapter describes the baseline water quality environment within the study area. The purpose of the baseline water quality sampling program was to characterize the pre-project water quality conditions, such that impacts from construction and operation of the Project on the receiving water quality can be predicted and monitored. The impacts of the proposed Deltaport Third Berth Project on water quality in the study area are assessed and mitigation measures identified to ameliorate any potential impacts. This chapter is based on a report by EVS Environment Consultants-Golder Associates Ltd. titled Water Quality Report - Roberts Bank Expansion Project (2004), which is presented in full in Technical Volume STUDY AREA The study area was within a 5 to 7 km radius of the existing port facilities including reference sites. It was limited to the northwest by the influence of the main arm of the Fraser River and to the southeast by the existing BC Ferries terminal causeway. The study area is shown in Figure 8.1. Environmental Assessment Application Page 219

2 Figure 8.1 Water Quality Sampling Locations

3 8.3 METHODOLOGY The purpose of the baseline water quality sampling program was to characterize the pre-project water quality conditions, such that post-project impacts on these can be predicted and monitored. The water quality sampling program assessed the following questions regarding baseline water quality conditions in the Roberts Bank surface water: What is the pre-project range of values for water quality parameters in the surface waters around the Roberts Bank terminal, relative to the range of values at reference sites remote from the terminal? How do the values for water quality parameters vary spatially and temporally (i.e., seasonally) in the waters of the study area and at reference sites? How do the values for water quality parameters at the study and reference sites compare with established water quality guidelines (WQG)? Monthly water samples were taken at eight monitoring sites between Canoe Pass and the Ferry Terminal Causeway, and two reference sites off Westham Island, remote from the Roberts Bank terminal. The ten sampling stations were arranged in five pairs, each consisting of a nearshore station, on the landward side of the 5 m depth contour at the edge of Roberts Bank, and a farshore station on the open water side of the 5-m depth contour. At each station, one water sample was collected from immediately below the water surface ( surface samples), and one sample was taken from a location 2 m above the bottom ( deep samples). In October 2004 two locations were sampled in order to obtain additional data regarding nutrient inputs into the area between the BC Ferries and Roberts Bank port causeways. One sample was obtained at the outlet of an agricultural drainage ditch near the base of the BC Ferries causeway, and another sample was obtained from within the ditch itself. The water sample locations are shown on Figure 8.1. Specific water quality parameters considered in the study were: dissolved oxygen (DO) concentration, ph, Environmental Assessment Application Page 221

4 water temperature, turbidity, salinity, total suspended solids (TSS), ammonia nitrogen (NH 4 -N), nitrate nitrogen (NO 3 -N), nitrite nitrogen (NO 2 -N), dissolved ortho-phosphorus (ortho-p), and; chlorophyll a. Polycyclic aromatic hydrocarbons (PAHs) were included as a parameter for the October monitoring cycle Literature Review A literature review was undertaken to assist with determining appropriate water quality parameters and to determine historical data trends Field Surveys Sampling was conducted on May 5, June 2-3, June 30, August 12, and September 29- October 6, 2004, at or near the time of high tide. Water samples were collected and processed at each station according to standard procedures described in Environment Canada (1994) and the Puget Sound Estuary Program (PSEP) protocols (PSEP, 1987, 1997). At each of the monitoring and reference stations, one water sample was collected from immediately below the water surface ( surface samples), and one sample was taken from a location 2 metres (m) above the bottom ( deep samples). At nearshore stations, deep samples were taken at water depths of m, whereas at farshore stations, deep samples were taken at depths of m. Environmental Assessment Application Page 222

5 On September 29 and October 6, water samples were taken at depths of 0, 2, 4, 6, 8, 10, and 12 m at stations RB1b, RB2b, and RB3b, to assess the degree to which various water quality parameters varied with water depth. All water samples were collected using a 3-L Van Dorn sampler. The sampler was attached to a cable 2 m above a lead cannonball to prevent contamination of the water sample due to bottom disturbance. The sampler was triggered once the cannonball reached the bottom. From each 3-L water sample, the following containers were filled: one 250-mL amber glass jar for NH4-N (field preserved with sulphuric acid); one 500-mL high-density polyethylene (HDPE) bottle for NO3-N, and NO2- N,dissolved ortho-p, and TSS; and one wide-mouth plastic bottle for on-site measurement of DO, ph, and temperature using appropriate portable meters. Water samples for chlorophyll a analysis were field-filtered through a cellulosefibre filter using a portable filter system, preserved with magnesium carbonate and wrapped in tin foil. All the water chemistry sample containers were be packed in insulated coolers with freezer packs to maintain a temperature of approximately 4 degrees Celsius while on board the vessel and during storage and transport to the analytical laboratories. Sample collection log sheets contained observations of the time of collection, weather conditions (precipitation, wind speed and direction), tidal height, vessel drift and direction, vessel position during water sampling, and depth. Field water measurements conducted during the sampling event included the following parameters: DO was measured in situ using an Orion 835A dissolved oxygen meter set to the observed sample salinity. The meter has a resolution of 0.1 mg/l. ph was determined using a Horiba D-22 meter, which has a resolution of 0.01 relative ph units. Environmental Assessment Application Page 223

6 Concurrent temperature measurements were made with either the DO or the ph meter. Salinity was measured using a YSI 85 meter. Turbidity was measured using a Hach DR-890, which has a resolution of 1 FAU Laboratory Measurements All bulk water chemical analyses were performed by ALS Environmental, Vancouver, BC. Each water sample was analyzed for chlorophyll a; NH4-N, NO3-N, NO2-N, dissolved ortho-p, and TSS. A subset of samples (October 2004) was analyzed for polycyclic aromatic hydrocarbons (PAH). 8.4 EXISTING WATER QUALITY CONDITIONS Existing Water Quality Roberts Bank Dissolved oxygen (DO) (Figure 8.2) and temperature (Figure 8.3) were lower at deep stations than at surface stations. Surface DO and temperature concentrations did not vary noticeably between nearshore and farshore stations, but deep samples taken from farshore stations were generally cooler and had lower DO concentrations than deep samples from nearshore stations. In general, temperature and DO on Roberts Bank decrease with increasing depth. Because much of the DO in marine waters enters the water column from the surface, it is not surprising that surface waters are more oxygenated than deeper waters. Similarly, in the absence of mixing, the temperature of sun-warmed surface waters is expected to be higher than the water temperature at depth, provided the air temperature exceeds the water temperature. Environmental Assessment Application Page 224

7 A Dissolved oxygen (mg/l) Surface Depth 5 May 04 2 Jun Jun Aug 04 6 Oct 04 B Dissolved oxygen (mg/l) Surface Depth 5 May 04 2 Jun Jun Aug 04 6 Oct 04 Reference: Figure 2 EVS 2004 Note: Columns represent mean values for all stations at a given depth, and error bars indicate ranges of measured values. Figure 8.2 DO concentration at surface and depth locations (A: nearshore stations; B: farshore stations)

8 A Temperature ( C) Surface Depth 0 5 May 04 2 Jun Jun Aug 04 6 Oct 04 B Temperature ( C) Surface Depth 5 May 04 2 Jun Jun Aug 04 6 Oct 04 Reference: Figure 3 EVS 2004 Note: Columns represent mean values for all stations at a given depth, and error bars indicate ranges of measured values. Figure 8.3 Temperature at surface and depth locations (A: nearshore stations; B: farshore stations)

9 Turbidity (Figure 8.4) and TSS (Figure 8.5) were highly variable over the five-month sampling period, but were generally highest from May-late June, and declined during the August- September period. This reflects the influence of turbid Fraser River water on Roberts Bank, with the amount of turbidity and TSS reflecting the seasonal variation in river flow. Variation in turbidity and TSS among stations and sampling dates also reflects pre-sampling rainfall events, and wave-generated turbidity. Turbidity was generally highest in surface water samples, except for samples from Station RB5a, at which the highest turbidity measurements were observed. This station is located furthest north, and is more influenced by the Fraser River than the other stations. Salinity varied among stations, and this variability was most pronounced among nearshore stations (Figure 8.6). In general, salinity was greater at deep sites than at surface sites, and this reflects the influence of freshwater from the Fraser River and the estuarine character of the Roberts Bank environment. In estuaries, the less dense freshwater typically floats on top of the heavier salt water. Salinity was higher at the southernmost sampling stations, which are farthest away from the freshwater influence of the Fraser River. NH 4 -N and ortho-p concentrations were generally similar across stations and depths, whereas NO 3 -N concentrations were up to five times higher at the farshore stations than at nearshore stations (Figure 8.7). NO 2 -N concentrations were below detection limits in all samples taken. NO 3 -N concentrations were lowest at stations RB1a and RB1b, southeast of the Deltaport terminal, whereas ortho-p concentrations appeared to decrease slightly from north to south. Chlorophyll a concentrations were consistently higher at nearshore stations than at farshore stations, particularly during the June 2 sampling event (Figure 8.8). There do not appear to be any strong relationships between any of the individual nutrients concentrations and chlorophyll a concentration (Figure 8.9). Polycyclic aromatic hydrocarbons (PAHs) from all sample locations were recorded at levels below laboratory detection limits. Environmental Assessment Application Page 227

10 A Surface Depth Turbidity (FAU) May 04 2 Jun Jun Aug 04 6 Oct 04 B Surface Depth Turbidity (FAU) May 04 2 Jun Jun Aug 04 6 Oct 04 Reference: Figure 4 EVS 2004 Note: Columns represent mean values for all stations at a given depth, and error bars indicate ranges of measured values. Figure 8.4 Turbidity at surface and depth locations (A: nearshore stations; B: farshore stations)

11 A Total suspended solids (mg/l) May 04 2 Jun Jun Aug 04 6 Oct 04 B Total suspended solids (mg/l) May 04 2 Jun Jun Aug 04 6 Oct 04 Reference: Figure 5 EVS 2004 Note: Columns represent mean values for all stations at a given depth, and error bars indicate ranges of measured values. Figure 8.5 Total suspended solids (TSS) at surface and depth locations (A: nearshore stations; B: farshore stations)

12 A Surface Depth Salinity (ppt) May 04 2 Jun Jun Aug 04 6 Oct 04 B Salinity (ppt) Surface Depth 5 May 04 2 Jun Jun Aug 04 6 Oct 04 Reference: Figure 6 EVS 2004 Note: Columns represent mean values for all stations at a given depth, and error bars indicate ranges of measured values. Figure 8.6 Salinity at surface and depth locations (A: nearshore stations; B: farshore stations)

13 A Nitrogen/phosphorus (mg/l) May 04 2 Jun Jun Aug 04 6 Oct 04 Ammonia Nitrate Nitrite Ortho-P Nitrogen/phosphorus (mg/l) B May 04 2 Jun Jun Aug 04 6 Oct 04 Ammonia Nitrate Nitrite Ortho-P Reference: Figure 7 EVS 2004 Note: The column represents the mean value for all stations at a given depth, and the error bars indicate the range. Figure 8.7 Nutrients at depth (A: nearshore stations; B: farshore stations)

14 Chlorophyll a (µg/l) A May 04 2 Jun Jun Aug 04 6 Oct 04 B 6.0 Chlorophyll a (µg/l) May 04 2 Jun Jun Aug 04 6 Oct 04 Reference: Figure 8 EVS 2004 Note: The column represents the mean value for all stations at a given depth, and the error bars indicate the range. Figure 8.8 Chlorophyll a at depth (A: nearshore stations; B: farshore stations)

15 0.06 Ammonia-N (mg/l) May 04 2 Jun Jun Aug 04 6 Oct Nitrate-N (mg/l) May 04 2 Jun Jun Aug 04 6 Oct 04 Ortho-P (mg/l) Chlorophyll a (µg/l) 5 May 04 2 Jun Jun Aug 04 6 Oct 04 Reference: Figure 9 EVS 2004 Figure 8.9 Correlation between nutrient and chlorophyll a concentrations, Roberts Bank, Delta, BC

16 8.4.2 Water Quality In and Near the Agricultural Ditch Temperature, ph, TSS, salinity, and concentrations of DO, NH4-N, NO3-N, NO2-N, and dissolved ortho-p measured at station RB6 (near the agricultural ditch outflow) on October 6, 2004 were within the range of values obtained at sites elsewhere on Roberts Bank on the same date. However, the concentration of chlorophyll a at station RB6 was lower than at any of the other sites sampled. TSS, NH4-N, NO3-N, NO2-N, and dissolved ortho-p were measured within the drainage ditch on October 6, Values for all of these parameters were much higher than those measured at any of the Roberts Bank stations, including those at station RB5, near the mouth of the ditch. Although water in the ditch is very nutrient-enriched relative to the waters of Roberts Bank, the ditch s inflow did not appear to be affecting the water quality in the intercauseway area on October 6, nor did it appear to be causing increased algal production (as measured by the concentration of chlorophyll a in the water) Comparison of Roberts Bank Water Quality to Agency Objectives/Guidelines Water quality objectives (WQO) or water quality guidelines exist for several of the parameters measured during the Roberts Bank water sampling program. Twenty-four of the 99 DO measurements were below the chronic WQO of 8.0 mg/l (mean of 5 samples collected within a 30-d period) set by Swain et al. (1998), but none of the measurements were below the instantaneous minimum of 5.0 mg/l. All of the low DO measurements were taken from deep samples. Based on these measurements, harm to DO-sensitive species (e.g., salmonids) is not expected. For water temperatures of 15 C, salinity of 20 ppt, and ph of 8.0, the maximum allowable ammonia concentration is 9.8 mg/l and the allowable 30-d average concentration is 1.5 mg/l (BCMWLAP 1998). All measured ammonia-n concentrations were non-detectable or below half of the 30-day average guideline. Therefore, ammonia related toxicity is not expected Comparison with Historical Water Quality Data Historical data for Roberts Bank and environs were available from data compilations conducted by Triton (2001) and Swain et al. (1998). All parameters were within the range reported for Environmental Assessment Application Page 234

17 sampling stations at the Brandrith Pump Station (located between the Roberts Bank and BC Ferries jetties), Roberts Bank and Sturgeon Bank. At present the data is not adequate to assess any long-term or seasonal changes in water quality. 8.5 ASSESSMENT OF IMPACTS Assessment of Impacts During Construction Terminal land will be created through dredging and landfill operations. The terminal area to be filled will be surrounded by a system of containment dykes. Dredge material will be pumped into the contained area where the solids settle out. Decant water and suspended silt material will be completely contained during the landfill process and will be re-pumped via submerged pipeline to approved Environment Canada ocean disposal sites. The dykes surrounding the fill area will be built above high tide, thereby fully containing all materials and preventing spillover into surrounding foreshore areas. Concentrations of metals and PAHs in the study area sediments meet the Interim Contaminant Testing Guidelines as per the Canadian Environmental Protection Act (CEPA). Similarly, total organic carbon (TOC), sulphur and sulphides are at low concentrations. These potential impacts are discussed in Chapter 9 Sediment Quality. Therefore disturbance of sediment during the proposed dredging operations and remobilisation of these low concentrations of contaminants to the water column is likely to cause negligible risk to human health or the environment. Dredging operations and construction activities have the potential to increase TSS levels in the water column. To mitigate the effects of construction activities, dredging guidelines have been established by DFO for the protection of marine resources susceptible to TSS levels at Roberts Bank: No dredging is permitted in waters less than -5m (CD) deep from March 1 to August 15 for the protection of juvenile salmon unless the works area is adequately isolated from fish bearing waters to the satisfaction of DFO. Further construction phases in the intertidal zone are concentrated to occur during the winter to minimize disruption to eelgrass and to intertidal mudflats which makes these habitats less susceptible to increased TSS levels. Environmental Assessment Application Page 235

18 Other potential impacts to water quality during construction could result from accidents and malfunctions, namely spills and leaks, from construction equipment. These potential impacts are discussed in Chapter 19 Accidents and Malfunctions Assessment of Impacts During Operation During operation, treated sewage effluent is discharged from the Deltaport terminal as well as stormwater effluent, which has the potential to contain contaminants and to impact water quality. The Deltaport terminal sanitary sewers collect domestic and industrial wastewater generated in building facilities and wash down areas. The proposed increase in sewage output generated by the Project is low, and will fall within the current operating requirements of the existing Deltaport sanitary sewage treatment plant. The Deltaport sanitary sewage treatment plant was constructed as part of the initial Deltaport container terminal development in 1997 and provides secondary sewage treatment. The sewage treatment plant is permitted under a Ministry of Water Land and Air Protection (MWLAP) effluent permit PE to discharge treated effluent into the Deltaport ship berth at a depth of 12 metres below mean low water. The maximum authorized rate of discharge is 44 cubic metres per day and the characteristics of the discharge are: 5-day biochemical oxygen demand (BOD 5 ) 45 mg/l, maximum Total suspended solids (nonfilterable residue) 45 mg/l, maximum Toxicity, LT hours, minimum. Although disinfection of the effluent is not require at this time, the Deltaport sewage treatment plant has been designed to accommodate disinfection facilities in the future. Storm water from the Deltaport terminal will pass through an oil interceptor and sedimentation tank to collect possible contaminants prior to discharge of storm water effluent to the ocean. The eight existing storm outfalls, located along the northern perimeter of Deltaport, will be decommissioned and replaced by five new storm outfalls. In addition the new storm outfalls will be fitted with shut-off valves to terminate flow from the Project should a sizeable spill occur on the terminal and enter the storm water system. Environmental Assessment Application Page 236

19 Accidents and malfunctions that could possibly occur during Project operation have the potential to impact on water quality. These accidents and malfunctions include: spills and leaks (which include those from Project fuelling operations and from terminal operations); transportation of dangerous goods; and waste management. In addition liquid emissions from ships, including ballast water and bilge water discharges, also have the potential to impact on water quality. These potential impacts are discussed in Chapter 19 Accidents and Malfunctions. 8.6 MITIGATION MEASURES Construction The mitigation measures to address potential water quality impacts during construction are discussed in the Construction EMP, located in Chapter 21 Environmental Management Program Operation The operation of the Deltaport Third Berth is anticipated to have minimal effects on water quality in the study area. Once operational, terminal activities are to be conducted in accordance with the Operation EMP to prevent contamination or degradation of the water quality from operational activities. The mitigation measures to address potential water quality impacts during operation are discussed in the Operation EMP located in Chapter 21 Environmental Management Program. 8.7 RESIDUAL EFFECTS Provided the safeguards included in this chapter and the plans outlined Chapter 21 Environmental Management Program are undertaken, no significant environmental impacts on water quality are likely to occur. Environmental Assessment Application Page 237

20 9.0 SEDIMENT QUALITY 9.1 INTRODUCTION Construction of the proposed Deltaport Third Berth Project requires dredging for wharf construction, ship channel extension, terminal land construction and material sourcing of fill for terminal land (borrow areas). The dredging volumes provided herein should be considered preliminary as they will require further engineering assessment. An additional geotechnical investigation program is on-going and the sediment information collected will be used to refine the dredge volumes as part of final engineering design. It is estimated that up to 2 million cubic metres of the total dredge volume (approximately 3.5 million cubic metres) would be unsuitable for use as onsite fill. The VPA will use the unsuitable silt fill material, where possible, for beneficial use as part of the proposed habitat compensation measures. However, a large portion of the waste silt and excess dredged materials will require ocean disposal at nearby historic ocean disposal sites that will be re-activated for the Project, as shown on Figure 9.1. A sediment quality assessment was undertaken by Hemmera Envirochem Inc. in August 2004 to address the requirement to obtain a Disposal at Sea Permit for Dredged Material from Environment Canada, as per the Canadian Environmental Protection Act (CEPA). The sediment sampling report, Deltaport Third Berth Sediment Sampling Program (2004), is presented in full in Technical Volume 4. In addition to meeting the information requirements for the Disposal at Sea Permit for Dredged Material, the sediment sampling report was also used in order to assist with assessing potential impacts on sediment quality associated with the construction and operation of the proposed Deltaport Third Berth Project. The potential impacts to sediment quality are described later in this chapter. Environmental Assessment Application Page 238

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22 9.2 THE STUDY AREA The study area for the sediment quality assessment corresponds to the proposed Deltaport Third Berth Project dredging areas. Dredging is required for wharf construction, ship channel extension, terminal land construction and borrow areas. Dredging volume estimates are provided below and are described in more detail in Chapter 2 Project Description. The dredging program will require further engineering assessment and the estimated volumes given below should be considered preliminary. Dredging for Reclamation (terminal fill): 2,000,000 m 3 Dredging under Caissons and Terminal: 1,220,000 m 3 Dredging for Ship Channel Extension: 250,000 m 3 The dredging, disposal and terminal fill activities are proposed to take place from August 2005 through to November A detailed construction schedule showing the breakdown of construction activities is provided in Chapter 2 Project Description. Preliminary dredging area locations are provided on Figure 9.2. Environmental Assessment Application Page 240

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24 9.3 METHODOLOGY The sampling program and sampling methodology was developed with input from Environment Canada through their review of the draft sediment sampling work plan. Sediment samples, which consisted of both core and surface grab samples, were collected from the study area by barge and by boat. Sediment sampling locations were coordinated with the geotechnical drilling program which involved six cone penetration tests (CPTs) in the wharf and terminal area and 10 boreholes (BH) as described below and shown in Figure 9.3: BH201 to BH203 in the terminal area with a depth of m below mud line (dredge depth in this area could be up to 40 metres below mud line); and BH204 to BH210 in the existing shipping channel (north end) and in the turning basin area with a sample depth up to 15 m (dredge depth in this area could be up to 15 m below mud line). A total of 45 sediment samples were collected (25 core samples and 20 surface grab samples) as shown on Figure 9.3. The 25 core samples were collected from the 10 geotechnical borehole locations and the 20 surface grab samples were collected from the 10 geotechnical borehole locations, two at the CPT locations and eight other surface grab locations. Environmental Assessment Application Page 242

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26 At the time of collection the following sediment sample characteristics were recorded: sediment texture (e.g., sandy silt); colour and odour; anthropogenic and non-anthropogenic sediment sample characteristics; and visual evidence of contamination. As per Environment Canada s Ocean Disposal Regulations and Interim Contaminant Testing Guidelines, each sample was analysed in the laboratory for: total organic carbon (TOC); PAHs; total metals, including cadmium and mercury; and grain size. In addition to the Environment Canada required parameters, fifteen samples were analysed for total sulphur and total sulphides to assist with material characterization in support of proposed sediment use for habitat compensation features. There are no criteria for total sulphur and sulphide levels in marine sediments. These results will be used in conjunction with other sediment analyses, including particle size and TOC, to determine salt marsh and eelgrass bed preparation requirements as part of the detailed design of the habitat compensation features, in the event that this material is used for beneficial use. 9.4 EXISTING ENVIRONMENT Sediment Quality Sediment quality results were compared to the Environment Canada disposal at sea criteria, presented below in Table 9.1. Environmental Assessment Application Page 244

27 Table 9.1 Minimum Analysis for Dredged Material Trace Metals Parameter Mercury Cadmium Disposal at Sea Regulation (Dry Weight) 0.75 µg/g 0.6 µg/g Organics PAH 2.5 µg/g Others Total Organic Carbon (TOC) Particle Size No criteria No criteria The sediment sampling results are summarised below and are presented in two categories: core sample results and surface sample results. The complete laboratory results for all samples, including the QA/QC program, are included in the sediment sampling report, Technical Volume 4. Core Samples Mercury concentrations ranged between 0.1 µg/g and 0.05 µg/g in the core samples. Cadmium concentrations ranged between <0.2 µg/g and 0.5 µg/g; and PAH concentrations ranged between 0.06 µg/g and 0.12 µg/g. A summary of the core sample results, along with the disposal at sea criteria is presented below in Table 9.2. Environmental Assessment Application Page 245

28 Table 9.2 Summary of Core Sample Results Trace Metals Parameter Minimum Result Maximum Result Disposal at Sea Regulation (Dry Weight) Mercury (µg/g) µg/g Cadmium (µg/g) < µg/g Organics PAH (µg/g) µg/g Others Total Organic Carbon (TOC) % <0.5 % 1.39 % No criteria Particle Size n/a n/a No criteria Beneficial Use Total Suphides (µg/g) No criteria Sulphur (%) 0.06 % 0.16% No criteria All of the core samples collected in the study area had concentrations of trace metals and PAHs that met the disposal at sea criteria as per CEPA. Concentrations of TOC in the study area were generally low, ranging from <0.5 % to 1.39 %. Most core sediment samples contained less than 0.5% TOC. Sediment grain size varied from sand with some silt to sandy silt. The total sulphide concentrations in the core samples ranged from 8.6 to 315 µg/g and sulphur content ranged from 0.06 to 0.16 %. Surface Sediment Samples Mercury concentrations ranged between 0.02 µg/g and 0.07 µg/g in surface sediment. Cadmium concentrations ranged between <0.2 µg/g and 0.4 µg/g; and PAH concentrations ranged between 0.06 µg/g and 1.13 µg/g. A summary of the surface grab sample results, along with the disposal at sea criteria is presented below in Table 9.3. Environmental Assessment Application Page 246

29 Table 9.3 Summary of Surface Sample Results Trace Metals Parameter Minimum Result Minimum Result Disposal at Sea Regulation (Dry Weight) Mercury (µg/g) µg/g Cadmium (µg/g) < µg/g Organics PAH (µg/g) µg/g Others Beneficial Use Total Organic Carbon (TOC) % < No criteria Particle Size n/a n/a No criteria Total Suphides No criteria (µg/g) Sulphur (%) 0.11 % 0.48 % No criteria All of the surface grab samples collected in the study area had concentrations of trace metals and PAHs that met the disposal at sea criteria as per CEPA. Concentrations of TOC in the study area are generally low, ranging from <0.5 % to 1.55 %. Grain size analyses indicate that surface sediment ranged from sand with trace silt to sandy silt. The total sulphide concentrations ranged from 87.4 to 1160 µg/g and sulphur content ranged from 0.11% to 0.48 %. The total sulphide and sulphur concentrations observed from the surface grab samples were higher than those observed in the core samples. 9.5 ASSESSMENT OF IMPACTS Assessment of Impacts During Construction Terminal land will be created through dredging and landfill operations. The terminal area to be filled will be surrounded by a system of containment dykes. Dredge material will be pumped into the contained area where the solids settle out. Decant water and suspended silt material will be completely contained during the landfill process and will be re-pumped via submerged pipeline to approved Environment Canada ocean disposal sites. The dykes surrounding the fill area will be built above high-tide, thereby fully containing all materials and preventing spill-over into surrounding foreshore areas. Environmental Assessment Application Page 247

30 Concentrations of metals and PAHs in the study area meet the Interim Contaminant Testing Guidelines as per CEPA. Similarly, TOCs, sulphur and sulphides are at low concentrations. Therefore disturbance of sediment during the proposed dredging operations and remobilisation of these low concentrations of contaminants is likely to cause negligible risk to human health or the environment. Once the sediment is deposited at the ocean disposal sites, Environment Canada s Disposal at Sea Program is responsible for monitoring the disposal sites. Potential impacts to sediment quality during construction could result from accidents and malfunctions, namely spills and leaks, from construction equipment. These potential impacts are discussed in Chapter 19 Accidents and Malfunctions Assessment of Impacts During Operation Potential accidents and malfunctions that could occur during Project operation have the potential to impact sediment quality. These accidents and malfunctions include: spills and leaks (which include those from Project fuelling operations, liquid emissions from ships (ballast water and bilge water) and from terminal operations); transportation of dangerous goods; and waste management. These potential impacts are discussed in Chapter 19 Accidents and Malfunctions. In addition to accidents and malfunctions, stormwater, which has the potential to contain contaminants, has the potential to impact sediment quality. Stormwater from the terminal will pass through an oil interceptor and sedimentation tank to collect possible contaminants prior to discharge of storm water effluent to the ocean. The eight existing storm outfalls, located along the northern perimeter of Deltaport, will be decommissioned and replaced by five new storm outfalls. In addition the new storm outfalls will be fitted with shut-off valves to terminate flow from the Project should a sizeable spill occur on the terminal and enter the stormwater system. Environmental Assessment Application Page 248

31 Wastewater discharges are not anticipated to impact sediment quality as the wastewater will be treated at the existing on-site wastewater treatment facility. 9.6 MITIGATION MEASURES Construction The mitigation measures to address potential sediment quality impacts during construction are discussed in the Construction EMP, located in Chapter 21 Environmental Management Program Operation The operation of the Deltaport Third Berth is anticipated to have minimal effects on sediment quality in the study area. Once operational, terminal activities are to be conducted in accordance with the Operation EMP to prevent sediment contamination from operational activities. The mitigation measures to address potential sediment quality impacts during operation are discussed in the Operation EMP located in Chapter 21 Environmental Management Program. 9.7 RESIDUAL EFFECTS AND CONCLUSION Provided the safeguards included in this chapter and the plans outlined Chapter 21 Environmental Management Program are undertaken, no significant environmental impacts from sediments are likely to occur. All of the sediment samples collected in the study area had concentrations of trace metals and PAHs that met the disposal at sea criteria as per CEPA. Environmental Assessment Application Page 249