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4.0 Results and Discussion

In this section, both water column and sediment parameters will be compared with existing water quality objectives established for the Burrard Inlet (see Appendix I) (Nijman and Swain 1990), or the applicable water/sediment quality guidelines in those instances where objectives have not been established. For the purposes of determining compliance with guidelines and objectives, the water uses that are being protected in the Burrard Inlet include: sensitive aquatic life and wildlife, and primary (e.g. swimming, water skiing) and secondary (e.g. canoeing, boating) contact recreation. In False Creek, both aquatic life and wildlife values are protected, as well as primary contact near the mouth of the creek.

4.1 Water Column

Water samples were collected at six sites throughout the Burrard Inlet (English Bay at Locarno Park, Vancouver Harbour at Clarke Drive, Vancouver Harbour at Vancouver Wharves, Second Narrows Chevron, Port Moody IOCO and Indian Arm at Cable Crossing), as well as one site in False Creek (False Creek East End), and analyzed for chlorophenols, PCBs, metals and nutrients. Samples were also collected at five other sites (Vancouver Yacht Club in English Bay, Granville Island in West False Creek, Mosquito Creek, Port Moody Arm at Reed Point and Deep Cove) and analyzed for MTBE only. One sample was collected at Coal Harbour and analyzed for both the general chemical parameters (chlorophenols, PCBs, metals and nutrients) as well as MTBE. Water quality results from these sites are included in Appendix II.

4.1.1 PCBs and Chlorophenols

All of the PCBs sampled at these eight sites were present in concentrations below detection limits (<0.1 µg/L), as were both tetra- and pentachlorophenol (detection limits of <0.005 µg/L 2,3,4,5 - tetrachlorophenol, <0.002 µg/L 2,3,4,6 - tetrachlorophenol, and <0.005 µg/L pentachlorophenol). However, although there are currently no water quality objectives proposed for PCB concentrations in water in the Burrard Inlet, the guidelines for the protection of freshwater and marine aquatic life from PCBs range between 0.00025 ng/L for 3,3',4,4',5-pentachlorobiphenyl and 0.04 ng/L for 3,3',4,4'-tetrachlorobiphenyl, and the total concentration of all PCB's should not exceed 0.1 ng/L. Therefore, the detection limits for the analytical method used to measure this parameter were too high by a factor of at least 1000, and so it is not possible to determine if PCB's are a concern at these sites.

A water quality objective of a maximum of 0.2 µg/L has been proposed for the total concentration of chlorophenols in the Burrard Inlet between 1st and 2nd Narrows. The detection limits for both tetra- and pentachlorophenol are well below this objective. Therefore, chlorophenols are not a concern at present at these sites.

4.1.2 Metals

Concentrations of aluminum at the seven marine sites ranged from below detection limits (<0.06 mg/L) at Port Moody Arm, Indian Arm, Second Narrows Chevron and Coal Harbour to a maximum of 0.19 mg/L at Vancouver Harbour at Vancouver Wharves. The concentration of aluminum measured at the False Creek East End site was 0.12 mg/L.

There is currently no water quality guideline for aluminum concentrations in marine waters, and no objective has been proposed for either Burrard Inlet or False Creek.

A water quality objective of 0.01 mg/L is in place for arsenic in waters between 1st Narrows and Roche Point. Arsenic concentrations measured at all of the sites were below detection limits (<0.06 mg/L); however, this detection limit is six times the water quality objective limit, making it impossible to interpret the data relative to the objective value. It is recommended that future analyses of water samples collected at these sites use a method with a detection limit of lower than 0.01 mg/L, preferably 0.001 mg/L.

A water quality objective has been proposed for barium concentrations between 2nd Narrows and Roche Point. The objective is that maximum total barium concentrations should not exceed 0.5 mg/L. As concentrations of this metal ranged between 0.003 mg/L at Vancouver Harbour - Vancouver Wharves to a maximum of 0.01 mg/L at Locarno Park, it does not appear that this metal is a concern.

Boron concentrations measured at the seven sites ranged from 2.45 mg/L at the Indian Arm site to 3.25 mg/L at Coal Harbour. While there is no water quality objective for this metal, the water quality guideline for the protection of marine aquatic life is a maximum value of 5 mg/L, and so it appears that boron concentrations are not a concern.

Total cadmium concentrations were below detection limits (<0.006 mg/L) at all of the sites monitored, and therefore well below the 0.043 mg/L maximum objective for waters between the 1st Narrows and Port Moody Arm.

A water quality objective of a maximum of 0.05 mg/L exists for total chromium concentrations in False Creek as well as between 2nd Narrow and Port Moody Arm. The majority of sites monitored in 2000 had concentrations below detection limits (<0.006 mg/L), although the Indian Arm at Cable Crossing site had a concentration equal to the detection limit (0.006 mg/L), and the Port Moody IOCO site had a concentration of 0.009 mg/L. These values are well below the objective, and so chromium does not appear to be a concern in the waters of Burrard Inlet.

Concentrations of both total cobalt and total copper were below detection limits (<0.006 mg/L for both metals) for all samples collected. There is no guideline for cobalt concentrations in marine waters. However, the objective for copper concentrations in the Burrard Inlet is an average value not exceeding 0.002 mg/L and a maximum value not exceeding 0.003 mg/L. Therefore, the detection limit used to analyze copper concentrations is too high to determine if the water quality objective is being exceeded. Preferably, an analytical method with a detection limit of 0.0002 mg/L would be used to analyze copper.

A water quality objective of 0.3 mg/L has been proposed for total iron concentrations in the majority of Burrard Inlet, except for the reach between 2nd Narrows and Roche Point. Iron concentrations measured at the eight monitoring locations ranged between 0.06 mg/L at Port Moody IOCO to a maximum of 0.185 mg/L at Locarno Park in English Bay, and were therefore below the maximum objective value.

Lead concentrations were below detection limits (<0.06 mg/L) at all sites. However, the water quality objective for lead concentrations in Burrard Inlet is an average value of 0.002 mg/L and a maximum of 0.14 mg/L. While the maximum value was met in all instances, the detection limit was too high to determine if the average objective was exceeded. A minimum of five samples in a 30-day period are required to calculate an average, and so if this sampling frequency is ever met, the analytical method used to determine lead concentrations should have a detection limit significantly lower than 0.002 mg/L (preferably 0.0002 mg/L).

Nickel concentrations were also below detection limits at all sites (<0.02 mg/L), but again, while the detection limit is below the maximum objective (0.075 mg/L) it exceeds the average objective of 0.008 mg/L. Again, should sampling frequencies increase to the point where an average value could be calculated, a more sensitive analytical method should be employed.

The final objective for metals concentrations in the Burrard Inlet water column applies to zinc. The objective for a maximum concentration is 0.095 mg/L, while the average objective is to be 0.086 mg/L. Zinc concentrations were below both of these limits at all of the sites, ranging from 0.032 mg/L at Indian Arm to a maximum of 0.046 mg/L at Coal Harbour.

4.1.3 MTBE

In early December 2000, water samples were collected at the Vancouver Yacht Club, Granville Island in West False Creek, Mosquito Creek and Coal Harbour in the Vancouver Harbour, the Reed Point Marina in Port Moody Arm, and the Deep Cove Yacht Club in Indian Arm and analyzed for MTBE. Concentrations of MTBE in all of these samples was below detection limits (<0.001 mg/L). The most stringent guideline for this parameter is 0.02 mg/L to protect primary contact recreation, and so MTBE is not a concern at these sites.

4.2 Sediment Quality

In December 2000, Phleger core samples were collected at 11 different sampling locations throughout the Burrard Inlet, and Ponar grab samples were collected at another five locations. Sediment cores were split into upper and lower portions (0-15 cm depth and 15-30 cm depth), to give an indication if long-term changes are occurring in the concentrations of contaminants. Sediment quality results from these sites are included in Appendix III.

4.2.1 Sediment Composition

The majority of the sites sampled had sediment compositions that were classified as loams, ranging from silt loams at the Vancouver Yacht Club in English Bay, Mosquito Creek and Port Moody Reed Point sites through silt-clay loams at Coal Harbour Site 2, sandy loams at Vancouver Harbour Vancouver Wharves, and simply loams at Coal Harbour Site 1. The Port Moody IOCO site had sediments classified as clays, while the Second Narrows Chevron and Vancouver Harbour at Clarke Drive sites were classified as sands.

4.2.2 PCBs and Chlorophenols

The majority of samples analyzed for PCBs had concentrations below detection limit (<0.005 µg/g). Exceptions to this were Aroclor 1254 and Aroclor 1260, which were present in measurable concentrations at number of the sites. Concentrations of Aroclor 1254 were measurable at five of the seven sites, with values ranging from a 0.015 µg/g to a maximum of 0.074 µg/g. Aroclor 1260 was measurable at two of the sites (False Creek East End in the shallow core sample, and Coal Harbour in the grab sample), with a maximum concentration of 0.068 µg/g. The current water quality objective for PCBs in sediment in the Burrard Inlet is a maximum of 0.03 µg/g dry weight, and this objective was exceeded in four of the seven samples analyzed for these parameters (Port Moody IOCO, Coal Harbour, Vancouver Harbour at Clarke Drive and False Creek East End in the shallow core sample). The highest concentration of total PCBs was 0.101 µg/g at the Coal Harbour site.

Concentrations of tetrachlorophenol were below detection limits (<0.0005 µg/g) at all of the sites where it was tested, and concentrations of pentachlorophenol were below detection limits (<0.0002 µg/g) at four of the seven sampling locations. Concentrations of pentachlorophenol in the remaining three samples ranged from 0.0006 µg/g at Vancouver Harbour at Clarke Drive to 0.0008 µg/g at Vancouver Harbour at Vancouver Wharves. The water quality objective (applicable only for the Burrard Inlet between the 1st and 2nd Narrows) is a maximum chlorophenol concentration of 0.01 µg/g dry weight, and so the two Vancouver Harbour samples had concentrations less than the objective. Therefore, it does not appear that chlorophenol concentrations are a concern in the Burrard Inlet.

4.2.3 Polycyclic Aromatic Hydrocarbons (PAHs)

PAH concentrations were above detection limits for almost all samples and for almost all species of PAH. The objectives apply to almost the entire Burrard Inlet, with the exception of Indian Arm. Because of this exclusion, sediment quality data for PAHs in Indian Arm is not considered in this section. A total of 27 samples were collected at the other sites, including all of the Ponar grab samples and both the deep and shallow core portions of the Phleger cores collected at the remaining sites.

The long-term objective for acenaphthylene concentrations in the Burrard Inlet is a maximum of 0.06 µg/g. This objective was exceeded in seven of the 27 samples collected, with a maximum concentration of 0.23 µg/g at the Port Moody Reed Point Site 2 in the deeper segment of the core sample. The fact that concentrations of this PAH were almost invariably higher in the deeper core sample at all sites indicates that it may be decreasing in recent years.

The sediment quality objective for acenaphthene in the Burrard Inlet is 0.05 µg/g dry weight. This objective was exceeded by six of 27 samples, with values ranging from 0.06 µg/g to 0.12 µg/g at Vancouver Harbour at Vancouver Wharves. Again, concentrations appear to be generally higher in the deeper sediment cores, suggesting that concentrations may be decreasing.

Anthracene concentrations exceeded the sediment quality objective of 0.1 µg/g for Burrard Inlet in 16 of 27 samples collected, with values ranging from 0.11 to 0.38 µg/g. The highest concentration was recorded in the deeper core sample from the Vancouver Yacht Club in English Bay Site 2.

The sediment quality objective for benzo(a)anthracene is 0.13 µg/g for the Burrard Inlet. This value was exceeded by 18 of the 27 samples collected, with a maximum value of 1.04 µg/g recorded at the shallower core sample collected at the Vancouver Yacht Club at English Bay Site 2.

Concentrations of benzo(a)pyrene ranged from 0.04 µg/g in the deeper cores from Mosquito Creek Site 1 and Coal Harbour Site 1 to a maximum of 0.82 µg/g in the deeper core segment from the Vancouver Yacht Club at English Bay Site 2. The objective for this parameter is 0.16 µg/g, and this value was exceeded by 18 of 27 samples. The maximum recorded value occurred in the deeper core sample from the Vancouver Yacht Club at English Bay Site 2.

The sediment quality objective for benzofluoranthenes in Burrard Inlet sediments is a maximum of 0.32 µg/g. This objective was exceeded by 20 of 27 values, with a maximum concentration of 2.41 µg/g in the deeper core sample from the Vancouver Yacht Club in English Bay Site 2.

The sediment quality objective of 0.07 µg/g for benzo(g,h,i)perylene was exceeded by 26 of the 27 samples collected, with a maximum concentration of 0.32 µg/g measured in both the shallow portion of the core from the False Creek East End site and the shallow core from the Granville Island in West False Creek Site 2.

Twenty-two of the 27 samples collected throughout the Burrard Inlet had chrysene concentrations exceeding the objective of 0.14 µg/g. The maximum concentration (1.83 µg/g) was measured in the deeper core of the sample collected at the Vancouver Yacht Club Site 2.

The sediment quality objective for dibenz(a,h)anthracene was exceeded by relatively few of the samples, with only nine of 27 values higher than the objective value of 0.06 µg/g. The maximum exceedence occurred at Coal Harbour Site 1, in the shallow portion of the Phleger core collected.

A total of 25 of the 27 samples collected in the Burrard Inlet had fluoranthene concentrations exceeding the sediment quality objective of 0.14, with a maximum concentration of 1.39 µg/g occurring in the shallow core portion of the sample collected at the Vancouver Yacht Club at English Bay Site 2.

The sediment quality objective for fluorene in the Burrard Inlet is only 0.05 µg/g, and 15 of the 27 samples collected had concentrations higher than this. The highest concentration (0.16 µg/g) was found in the deeper core portion of the sample from the Vancouver Yacht Club at English Bay Site 2.

Almost all (26 of 27 samples) had indeno(1,2,3-c,d)pyrene concentrations exceeding the sediment quality objective of 0.06 µg/g, with a maximum value of 0.38 µg/g measured in the shallow portion of the core collected from Granville Island in West False Creek Site 2.

The sediment quality objective for naphthalene (0.2 µg/g) was exceeded by 10 of 27 samples collected at the sites throughout the Burrard Inlet. The maximum concentration was almost five times the objective value, at 0.97 µg/g, and was found in the deeper portion of the core collected at Granville Island in West False Creek Site 2.

The maximum phenanthrene objective of 0.15 µg/g was exceeded in 25 of the 27 samples, with a maximum value of 0.78 µg/g in the deeper core portion of the sample from the Vancouver Yacht Club in English Bay Site 2.

The final PAH measured in all of the sediment samples was pyrene, which has a maximum objective of 0.26 µg/g for the Burrard Inlet excluding Indian Arm. Concentrations of this PAH were generally extremely high, with 23 of the 27 samples exceeding the objective and the maximum concentration an extremely high 4.11 µg/g in the deeper core sample collected at Vancouver Yacht Club in English Bay Site 2.

It is obvious from this discussion that PAHs continue to be a significant concern throughout the Burrard Inlet, and especially in the English Bay and Granville Island areas. Of the fifteen PAHs analyzed in this section, the sites sampled at the Vancouver Yacht Club in English Bay tested higher than all other locations a total of nine times. The Granville Island in West False Creek was a distant second, with the highest concentration for a total of three of the 15 PAHs analyzed.

4.2.4 Metals

Sediment quality objectives proposed for all metals apply to the entire Burrard Inlet except for Indian Arm. This represents a total of 27 samples from the various sites, including Ponar grabs and Phleger cores, and considers the upper and lower portions of the cores as separate samples.

The sediment quality objective for arsenic concentrations in the Burrard Inlet is a maximum of 20 µg/g dry weight. This value was exceeded by only one of the 27 samples, with a concentration of 23 µg/g at the Granville Island in West False Creek Site 2 (deeper core segment). Concentrations at the remaining sites ranged between below detection limits (<8 µg/g) and 19 µg/g.

The second metal for which a sediment quality objective exists is cadmium. The long-term objective for this metal is a maximum of 1.0 µg/g dry weight. The objective was exceeded by 17 of 27 samples, with a maximum concentration of 2.5 µg/g found in the Ponar grab sample collected from Vancouver Harbour at Vancouver Wharves.

Concentrations of total chromium in sediment ranged from 24 µg/g in the Ponar grab sample from Vancouver Harbour at Clarke Drive to 68.8 µg/g the Port Moody Arm Reed Point Site 1 in the deeper sediment core. The maximum sediment quality objective for this metal is 60 µg/g dry weight, and this objective was exceeded by six of the 27 samples collected at the various sites.

A long-term total copper sediment concentration objective of 100 µg/g dry weight exists for the Burrard Inlet. A total of 18 of the 27 samples analyzed for this metal had concentrations exceeding this objective, with a maximum concentration of 985 µg/g at Vancouver Harbour at Vancouver Wharves. This value (almost ten times the objective value) was considerably higher than the next highest value, 239 µg/g, measured at the Coal Harbour Site 2 in the deeper portion of the core. However, the highest concentrations of copper were almost invariably found at the sites located between 1st and 2nd Narrows.

There is currently no sediment quality guideline for total iron concentrations in marine sediments. Concentrations at the various sites monitored in the Burrard Inlet ranged from 15,900 µg/g at Vancouver Harbour at Clarke Drive to 48,800 µg/g in the deeper portion of the core collected at Granville Island in West False Creek Site 2.

The sediment quality objective for total lead concentrations in the Burrard Inlet is a maximum of 30 µg/g dry weight. This value was exceeded by all samples save one (the deeper core from the False Creek East End site, which had a concentration of 24 µg/g). The maximum concentration measured was about nine times the objective value, at 269 µg/g, and occurred at Granville Island in West False Creek Site 1, in the deeper core segment.

No sediment quality objective or guideline for sediments exists for manganese concentrations in the Burrard Inlet. Concentrations at the various Burrard Inlet sites ranged from 95.5 µg/g at Vancouver Harbour - Clarke Drive to 450 µg/g at the Mosquito Creek Site 1 (deeper core).

The sediment quality objective for mercury in Burrard Inlet is 0.15 µg/g dry weight. Mercury concentrations were measured only in the Ponar grab samples and the core samples collected at the False Creek East End site. Six of the seven samples had concentrations exceeding the objective, with a maximum concentration of 1.76 µg/g measured at the Vancouver Harbour at Clarke Drive site.

Concentrations of total nickel in sediments ranged from 23 µg/g in the grab sample collected at the Second Narrows Chevron to a maximum of 52 µg/g measured at both the Vancouver Yacht Club in English Bay Site 2 (shallow core) and the Granville Island in West False Creek Site 2 (shallow core). No objective has been proposed for this metal in the Burrard Inlet, but the lowest effects limit guideline for nickel in marine waters is 30 µg/g (Nagpal et al. 1998). The guideline value was exceeded by 22 of the 27 samples analyzed throughout the Burrard Inlet (excluding Indian Arm).

While no objective exists for silver concentrations in Burrard Inlet sediments, a marine low-effects guideline of 1.0 µg/g dry weight has been developed (Nagpal et al. 1998). All of the samples measured had concentrations below the detection limit (<2 µg/g) with the exception of Vancouver Harbour at Clarke Drive, where a concentration of 4 µg/g was measured. However, because the detection limit used for this metal is twice the guideline value, no useful interpretation of these data can be made.

A sediment quality objective of 150 µg/g dry weight has been proposed for zinc concentrations in Burrard Inlet sediments. Concentrations of zinc measured at the various sites ranged from 73.7 µg/g in the deeper core collected from the False Creek East End site to 575 µg/g at the Vancouver Harbour at Vancouver Wharves site. A total of 19 of the 27 samples had concentrations exceeding the sediment quality objective for zinc.

4.3 False Creek East End - Special Case Study

In addition to the water and sediment samples collected at the False Creek East End site that have already been discussed in the previous sections, additional Phleger core sediment samples were collected at nine sub-sites at the False Creek East End. These samples were divided into upper and lower segments (0-15 cm depth and 15-30 cm depth) in the same manner as samples collected for the main study. Sediment samples were analyzed for PAHs and total metals concentrations.

4.3.1 Sediment Texture

The composition of all sediment cores collected at the False Creek sites ranged between loams and silt-clay loams at all sites. This is similar to the composition of sediments collected at the Burrard Inlet sites (see Section 4.2.1).

4.3.2 PAHs

PAH concentrations in sediment cores collected from the nine sites in False Creek showed an extremely consistent pattern. All values for all of the PAH species exceeded the applicable objectives for the protection of aquatic life, by factors ranging between about 4 and 2500 times. The highest single exceedence was for phenanthrene, where a maximum concentration of 385 µg/g was measured at Site 6 in the deeper core segment, compared to a sediment quality objective value for the Burrard Inlet (including False Creek) of only 0.15 µg/g. A distribution pattern was also clear, with the highest concentrations of all PAHs occurring almost invariably at sites 1, 2, 6 and 7 and lowest at Site 9 (compare total PAH values, Appendix IV). At the sites where PAH concentrations were highest, a comparison of values in the upper and lower segments shows a dramatic increase in PAH concentrations in the deeper sediment cores, suggesting that PAH depositions are decreasing at these sites. At sites 4 and 5 this trend appears to be reversed, with concentrations almost twice as high in the surface sediment core than in the deeper core. False Creek passes through a heavily industrialized area, and is subject to considerable contamination from PAHs. One matter that is somewhat confusing is the fact that Site 4 (which is surrounded by sites 1, 2, 6, and 7) does not show high concentrations of PAHs. The reason for this is unclear. While PAHs are obviously a considerable threat to aquatic life in False Creek, it appears that concentrations of these substances may be decreasing over time.

4.3.3 Metals

Arsenic concentrations at the nine False Creek sites ranged from 12 µg/g at Site 9 in the deeper core to 41 µg/g at Site 3 in both the shallow and deep cores. A total of six of the 18 samples collected and analyzed had concentrations of arsenic exceeding the sediment quality objective of 20 µg/g dry weight, including both samples from sites 3 and 6, and the deeper core sample only from sites 1 and 2.

Cadmium concentrations were as high or higher than the maximum objective value of 1.0 µg/g dry weight for all samples collected at the nine False Creek sites. Values ranged from 1 µg/g in the deeper core from Site 5 to 6.2 µg/g in the deeper core from Site 2. The majority of samples had concentrations two to three times the objective value.

The sediment quality objective for chromium in False Creek is 60 µg/g dry weight, a value that was exceeded by 10 of the 18 sub-samples collected. The maximum chromium concentration measured was approximately 1.5 times the objective value (91.4 µg/g) and occurred in the deeper core segment from Site 2. Other sites with higher-than-average chromium concentrations were sites 4 and 6. There was no obvious trend as to whether chromium concentrations are increasing or decreasing over time in False Creek sediments.

Sixteen of the 18 sub-samples collected at the nine False Creek Sites had copper concentrations exceeding the maximum sediment quality objective of 100 µg/g for Burrard Inlet. The two values below the objective value were 79.1 µg/g (at the deeper core from Site 5) and 99.3 µg/g (at the deeper core from Site 9). Concentrations at the other sites ranged from 103 µg/g in the deeper core segment from Site 3 to 238 µg/g in the shallow core from Site 2. This implies that copper continues to be deposited. Site 6 also had relatively high sediment copper concentrations.

No sediment quality objective exists for iron concentrations in Burrard Inlet sediments, nor is there a guideline. Concentrations ranged from 31,200 µg/g in the deeper core from Site 5 to 44,800 µg/g measured at both the deeper core from Site 2 and the shallow core from Site 6.

Concentrations of lead measured in the False Creek sediments exceeded the sediment quality objective value of 30 µg/g by a minimum of a factor of four in all instances. Values ranged from 123 µg/g in the deeper portion of the Site 5 core to a maximum of 355 µg/g in the deeper core from Site 2. Site 6 also had high lead concentrations in the sediment collected there.

Mercury were not measured in the sediments, and therefore it cannot be determined if concentrations exceeded the objective of 0.15 µg/g for False Creek.

No sediment quality objective exists for nickel concentrations in False Creek sediments, but the guideline is 30 µg/g. Concentrations at the nine sites ranged from 30 µg/g in the deeper portion of the Site 3 core to 48 µg/g in the deeper portion of the Site 2 core. Therefore, all but the lowest value exceeded the guideline for nickel. Nickel values seem to be at about the same concentration in both the surface and deep samples from the same sites.

Silver concentrations were generally below detection limits (<2 µg/g) at the various False Creek sites. Exceptions to this were two values equal to the detection limit (2 µg/g) in the deeper core from Site 7 and the shallow core from Site 9, a value of 6 µg/g in the deeper core from Site 5, and a maximum value of 11 µg/g in the deeper core from Site 2. No objective exists for silver concentrations in Burrard Inlet sediments, but the guideline for the protection of aquatic life gives a lowest effects level value of 1.0 µg/g. Therefore, while this guideline was definitely exceeded by four of the samples, a more sensitive analytical methodology is necessary to determine if exceedences also occurred at the other sites.

Zinc concentrations at the nine False Creek sites invariably exceeded the sediment quality objective of 150 µg/g, with values ranging between 274 µg/g in the deeper Site 5 core to a maximum of 1010 µg/g in the deeper Site 2 core.

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