Key Findings and Next Steps
During Phases 1 (2015-2017) and 2 (2018-2020), both legacy pollutants and emerging contaminants of concern were measured in sediment and mussels coast wide. Results are summarized below.
Phases 1 and 2
Pollution Tracker was designed to determine the relative state of marine pollution in coastal British Columbia over space and time and to provide:
- Information on contaminant hot spots along the BC coast;
- An early warning platform for new contaminants of potential concern;
- A foundation for more detailed site-, contaminant-, or species-specific assessments to inform priority setting and management initiatives; and,
- An opportunity for additional research projects, such as the evaluation of risks to southern resident killer whales and other aquatic biota from contaminant exposure.
Pollution Tracker Phase 1 (2015-2017) and Phase 2 (2018-2020) provide a high-quality coast wide baseline dataset. The pollutants detected in Phase 1 and 2 samples reflect a variety of sources, including local urban and industrial inputs to the marine environment (e.g., wastewater and effluent discharges, road run-off, stormwater inputs, shipping activities, pesticide use), external inputs (e.g., contaminants carried from other places via oceanic and atmospheric transport), and oceanographic factors (e.g., currents, water depth, bottom substrate). More detailed assessments of contaminant distributions and sources are underway.
Polychlorinated biphenyls (PCBs) were detected in all sediment and mussel samples, with the highest levels found in industrialized and port areas. The highest levels of PCBs were found in Victoria Harbour and Prince Rupert Harbour, reflecting historical activities and discharges to the marine environment, as well as oceanographic conditions (e.g., water depth, levels of water circulation and sedimentation). Total PCB levels in sediment at all sites were above the BC Lower Working Sediment Quality Guideline considered protective of killer whales (0.0037 μg/kg dry weight), indicating the potential for effects on killer whales and other marine mammals (not shown on bar graphs due to scale). Given that British Columbia’s killer whales are among the most PCB-contaminated marine mammals in the world, it is important that we give further attention to PCBs in their habitat.
Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), or dioxins/furans, were detected in all sediment and mussel samples analyzed, with the highest levels found in industrialized and port areas. For comparison to environmental quality guidelines, data are expressed on a toxicity equivalent (TEQ) basis, which incorporates a measure of the toxicity of individual compounds relative to the most toxic dioxin/furan compound: 2,3,7,8-TCDD. In sediment, levels in Victoria Harbour were above the probable effects level for marine invertebrates, the level above which adverse effects are likely. In mussels, levels were relatively high in Victoria Harbour and around Metro Vancouver, possibly due to past pulp mill discharges in these regions.
Polycyclic aromatic hydrocarbons (PAHs) were detected in all sediment and mussel samples analyzed. With a few exceptions, PAH levels were highest in industrialized and urban areas (e.g., Victoria Harbour, Prince Rupert Harbour), reflecting the multitude of PAH sources in these areas. Levels in mussels showed greater variability, with relatively high levels also measured in less populated coastal areas. Environmental quality guidelines are not available for total PAHs, though guidelines exist for certain individual PAH compounds. Additional ‘fingerprinting’ analysis of PAH data is being conducted, which will help distinguish between different PAH sources.
Polybrominated diphenylethers (PBDEs) were detected in all sediment and mussel samples analyzed. PBDE levels were highest in industrialized and port areas (Prince Rupert Harbour and Victoria Harbour). Levels were also relatively high in mussels collected from less industrialized areas of the coast, reflecting the tendency of PBDEs to bioaccumulate in marine foods webs. Total PBDE levels in sediment at many sites were above the BC Lower Working Sediment Quality Guideline considered protective of killer whales (1 μg/kg dry weight), indicating the potential for effects on killer whales and other marine mammals (not shown on bar graphs due to scale).
Tetrabromobisphenol A (TBBPA) was only detected in one sediment sample in Phase 1 and two sediment samples in Phase 2 and was not detected in mussels. These results suggest that despite its widespread use as a flame retardant, TBBPA is not found in appreciable quantities in sediment or mussels. It is, however, found in both industrial and relatively remote locations (e.g., Namu). Future sampling and analysis of sediment from remote areas will help confirm Phase 2 results. A marine sediment guideline is not currently available for TBBPA.
Hexabromocyclododecane (HBCD) was detected mainly in industrialized and port areas, with the highest sediment levels in Victoria Harbour. Mussel results, however, showed relatively high levels in some less industrialized areas (e.g., Fulford Harbour). These results suggest that this flame retardant is generally localized around urban areas where it is likely to be used in the construction and materials sectors. For context, all levels were well below Canadian Environmental Quality Guidelines protective of marine sediment-dwelling organisms and mammals that consume aquatic biota.
Cadmium, Lead, Mercury
Cadmium, lead, and mercury were detected in almost all samples analyzed. Levels measured in many samples exceeded sediment quality guidelines protective of marine benthic invertebrates.
- Cadmium levels in sediment from several sites on the central coast and north coast exceeded the probable effects level for marine invertebrates, the level above which adverse effects are likely. Cadmium concentrations in mussels were comparable coast wide. These results may reflect a wide geological (natural) source of this metal, rather than human activities.
- Lead levels were markedly higher in both sediment and mussel samples from Victoria Harbour and Prince Rupert Harbour relative to samples from the rest of the coast. This likely reflects localized urban and industrial activities.
- Mercury levels in sediment from Victoria Harbour were above the probable effects level for marine invertebrates, with relatively high levels also measured in Burrard Inlet, Prince Rupert Harbour, and Haida Gwaii. In mussels, mercury levels were similar coast wide. While some of this mercury can be attributed to natural geological sources, human activities both locally (e.g., pulp mills) and internationally (artisanal and small-scale gold mining, coal-fired generating stations) likely contribute.
Perfluorinated compounds (PFCs) were found in sediment and mussels from a relatively small percentage of sites but were detected in all regions of the coast. The distribution of PFCs was more widespread in Phase 2 when additional compounds were analyzed (29 or 30 compounds in Phase 2 vs. 13 compounds in Phase 1). While not detected at all sites, the persistence of PFCs underscores concerns about their effects in the marine environment and the need to continue to monitor this contaminant class.
Alkylphenols were detected coast wide, with the highest levels in sediment from industrialized areas (e.g., Victoria Harbour, Burrard Inlet, Prince Rupert). In mussels, alkylphenols were detected in most of the samples analyzed, with relatively high levels reported in both industrialized and port areas. These findings indicate that alkylphenols are released from many sources in coastal British Columbia.
Organotin levels in sediment were highest in Burrard Inlet and Victoria Harbour but were also detected in more remote locations (e.g., Haida Gwaii). Of the mussel samples analyzed, organotins were only detected in Victoria Harbour and Pender Harbour (one sample in Phase 1; three samples in Phase 2). Given the widespread presence of tributyltin (TBT) documented in shellfish in southwestern British Columbia in the 1990s,1,2 these results suggest that while TBT and other organotins continue to persist in the marine environment, levels may be decreasing since implementation of the 2002 ban on anti-fouling paints in Canada.
Legacy organochlorine pesticides were detected in samples coast wide. In sediment, the highest levels were found in Victoria Harbour, Burrard Inlet, Prince Rupert Harbour, and Esquimalt Harbour. In general, dichlorodiphenyltrichloroethane (DDT) was dominant in sediments. Levels of legacy pesticides in mussels were comparable among sites coast wide, with the highest levels measured in Victoria Harbour and Namu. DDT was dominant in mussels at most sites. These results highlight the persistence of organochlorine chemicals in the marine environment long after being banned, as well as possible new inputs from other parts of the world (where they are still in use) via atmospheric and oceanic transport.
Current Use Pesticides
Current use pesticides (CUPs) were detected coast wide. Results varied considerably between Phase 1 and Phase 2. In sediment, the highest Phase 1 levels were found in samples from Burrard Inlet and Tsawwassen, while in Phase 2 levels were relatively high in Victoria Harbour, Patricia Bay, Nanaimo, Prince Rupert Harbour, and the southernmost site in Haida Gwaii. Differences in Burrard Inlet CUP levels between Phase 1 and 2 are attributed to organonitrogen CUPs, which were dominant in Phase 1 but were not analyzed in many Burrard Inlet samples in Phase 2. In general, pendimethalin, flutriafol and alachlor were dominant in sediments. In mussels, the highest CUP levels were found in Nanaimo and Comox Harbour where permethrin, pendimethalin, and butylate were dominant. Pendimethalin, alachlor, and butylate are herbicides; permethrin is an insecticide; and flutriafol is a fungicide.
Pharmaceutical and personal care products (PPCPs) were detected in sediment and mussel samples coast wide. In Phase 1, PPCP analysis consisted of 12 compounds with only the antibacterial agent triclocarban detected, while in Phase 2 samples were analyzed for up to 90 compounds. Therefore, total PPCP concentrations are not comparable between Phase 1 and 2.
In Phase 2 sediment, the highest level was found near Nanaimo where only one PPCP (furosemide) was detected. While the PPCPs detected in sediment varied, triclocarban was most common. In mussels, the highest levels were found at Fulford Harbour and Sechelt, where virginiamycin M1 was the dominant PPCP at both sites. Virginiamycin M1 is an antibiotic used for livestock and is occasionally used to prevent microbial contamination of ethanol fuels.
Phase 1 results have been summarized in Noel et al. 2022 (under review) and will be posted once published. Key results include:
- Microplastics averaged 32.6 ± 5.3 particles per kg in sediment and 0.38 ± 0.04 particles per individual mussel
- Victoria Harbour and the North Coast were microplastics hotspots along the BC coast
- Polyester and polyethylene dominated the polymer patterns in sediment and mussels
Analysis of Phase 2 microplastics samples and interpretation of results is in progress.
Phase 3 of Pollution Tracker launched in 2021. It will build on Phase 1 and Phase 2 results at dedicated Pollution Tracker sites, expand the project’s spatial coverage and continue to lay the foundation for coast wide temporal and spatial trend analyses.
1. Horiguchi T, Li Z, Uno S, Shimizu M, Shiraishi H, Morita M, Thompson JAJ, Levings CD. 2004. Contamination of organotin compound and imposex in molluscs from Vancouver, Canada. Marine Environmental Research. 57: 75-88.
2. Stewart C, and Thompson JAJ. 1994. Extensive Butyltin Contamination in Southwestern Coastal British Columbia, Canada. Marine Pollution Bulletin. 28: 601-606.