Green/Cheakamus watersheds: Water quality report for the 2024 dry season

Executive summary

Water is essential for life, and steps are needed to understand, protect and restore its health in fish habitat throughout British Columbia. The Raincoast Healthy Waters program was launched in 2023 to establish community-oriented water pollution monitoring in select BC watersheds. Two Healthy Waters sampling events take place every year in each watershed – the first in the dry season (summer), and the second being in the wet season (winter). 

While the Healthy Waters program typically focuses its work within singular watersheds, this partnership featured two Whistler area watersheds: the Green River, which drains through the Lillooet and Fraser Rivers into the Strait of Georgia (watershed area of 875 km²) and the Cheakamus River which drains south via the Squamish River to Howe Sound (watershed area of 1,034 km²). Combined, these watersheds cover an area of 1,909 km². This report highlights results from the second dry (summer) season sampling carried out with the support and participation of the Whistler Lakes Conservation Foundation (WLCF). 

Briefly, the Healthy Waters – WLCF team determined basic water properties (temperature, conductivity, pH, dissolved oxygen and turbidity) in situ at sampling sites on August 20, 2024. Water samples were collected from five water categories, including source water (2 samples), stream and river water (7 samples), road runoff (6 samples), tap water (10 samples – pooled into a single composite sample) and marine water (one sample). The sampled were pooled into composite by category and then analysed for coliform, nutrients (6), physical parameters, metals (37), pesticides (62), polycyclic aromatic hydrocarbons (PAHs; 76), pharmaceuticals and personal care products (PPCPs; 141), polychlorinated biphenyls (PCBs; 209), alkylphenol ethoxylates (APEs; 4), bisphenols (BPs; 6), per- and poly-fluoroalkyl substances (PFAS; 40), and sucralose. Analysis of 6PPD-Quinone is pending.

We detected 91 contaminants out of 573 measured in the stream and river category – i.e. fish habitat – for the in the Green/Cheakamus watersheds, excluding nutrients, fecal coliform and physical parameters. Overall, the Green/Cheakamus watersheds had relatively good water quality in the dry season, but additional sampling and analysis will provide additional insight into contamination impacts from forest fires, domestic wastewater, industrial chemicals and road runoff on the health of this valued watershed. 

The Green/Cheakamus Watershed

Key findings

• This assessment of water quality in the Green/Cheakamus watersheds reflects the third of several site visits; our understanding of water quality in these watersheds will grow with additional sampling.
• We collected  composite water samples in the Green/Cheakamus River watersheds during the dry season (August 20, 2024).
• We analysed 587 contaminants in each water sample.
• Road runoff was the most contaminated water category in the dry season; it had the highest concentrations of E. coli, PFAS, PCBs, PAHs, and PPCPs.
• Source water was the second most contaminated water category in the dry season; it had the highest concentration of pesticides and bisphenols.
• The stream and river water and marine water samples were less contaminated than the above water categories in the dry season.
• Tap water was the least contaminated water category in the dry season.
• Overall, the Green/Cheakamus watersheds had relatively good water quality in this third sampling event, the second for the dry season:
  • There were two exceedances of Canadian Environmental Quality Guidelines (Exceedances of aluminum guideline for the protection of aquatic life in the stream and river and road runoff samples) .
  • There were no exceedances of Health Canada Drinking Water Quality Guidelines.

Background

Raincoast’s Healthy Waters Program (www.raincoast.org/waters/) delivers high-resolution, community-oriented water quality analysis to watersheds across southern British Columbia. The goal of Healthy Waters is to empower communities with the understanding of the status of water quality in their watersheds, to allow for local stewardship regarding both point and nonpoint source pollution. 

The Whistler Lakes Conservation Foundation (WLCF) studies, informs and acts to protect the waters in the Whistler area, including Alpha, Nita, Alta, Lost and Green Lakes, and their tributaries. The WLCF partnered with the Raincoast Healthy Waters team in 2023/24 to generate an analysis of contaminants of past, current and emerging concern in local waters. Water samples were collected from sites within two Whistler area watersheds: the Green River which drains northeast via the Lillooet and Fraser Rivers down into the Strait of Georgia and the Cheakamus River which drains south via the Squamish River to Howe Sound. Combined, these watersheds cover an area of 1,909 km².

A watershed based approach to sampling

We collect samples from five different categories of water in each of our partner watersheds: from source water, upstream of human impacts, down to the marine environment. 

Source water serves as an upstream reference sample, allowing us to determine which contaminants are being introduced as water traces its path down through the watershed. 

Stream and river samples allow us to investigate the quality of fish habitat directly, by collecting samples from streams, creeks, and rivers used by salmon and other fish species (either currently or historically). 

Road runoff serves as an impacted sample category of current concern, as many contaminants, including  PAHs, metals, surfactants and chemicals such as 6-PPD quinone can be washed off roadways and into fish habitat during rain events. 

We include tap water samples in our analysis as a way to bring our homes into the conversation – we borrow water from the environment in the form of municipal or well water, and generally return it to aquatic habitats in a more-degraded state in the form of storm and sewage effluent (treated or untreated).

Marine water samples provide insight into those contaminants that may degrade fish and whale habitat in the ocean, and enable an understanding of the contribution of land-based pollutants from the adjacent watershed to the marine environment.

Collectively, the lessons learned from our partnering watersheds will contribute to a greater understanding of threats to water quality across British Columbia, and ultimately what policy changes can be implemented to preserve the quality of water for the future of salmon, whales, and people.

References

Berthiaume, A., Galarneau, E., & Marson, G. (2021). Polycyclic aromatic compounds (PACs) in the Canadian environment: Sources and emissions. Environmental Pollution, 269, 116008.

B.C. Ministry of Water, Land, and Resource Stewardship. 2025. 6PPD-quinone Water Quality Guidelines – Freshwater Aquatic Life. Water Quality Guideline Series, WQG-24. Prov. B.C., Victoria B.C.

Ding, Y., Hayward, S. J., Westgate, J. N., Brown, T. N., Lei, Y. D., & Wania, F. (2023). Legacy and current-use pesticides in Western Canadian mountain air: Influence of pesticide sales, source proximity, and altitude. Atmospheric Environment, 308, 119882.

Environment and Climate Change Canada (ECCC), 2023. Update on Canada’s National Implementation plan – Under the Stockholm Convention on Persistent Organic Pollutants. https://www.canada.ca/content/dam/eccc/documents/pdf/cepa/En14-517-2023-eng.pdf.  Accessed in May 2024. 

Environment and Climate Change Canada (ECCC) and Health Canada, 2023. Draft State of Per and polyfluoroalkyl substances (PFAS). https://www.canada.ca/en/environment-climate-change/services/evaluating-existing-substances/draft-state-per-polyfluoroalkyl-substances-report.html. Accessed in May 2024. 

 

Government of Canada, Environment and Climate Change Canada and Health Canada, 1994. Canadian Environmental Protection Act – Priority substances list assessment report – Polycyclic Aromatic Hydrocarbons. https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/contaminants/psl1-lsp1/hydrocarb_aromat_polycycl/hydrocarbons-hydrocarbures-eng.pdf. Accessed in May 2024.

Government of Canada, 2017. Toxic substances list – hexachlorobenzene (HCB). https://www.canada.ca/en/environment-climate-change/services/management-toxic-substances/list-canadian-environmental-protection-act/hexachlorobenzene.html. Accessed in May 2024. 

Harris K.A., Dangerfield N., Woudneh M., Brown T.G., Verrin S., Ross P.S. 2008. Partitioning of current-use and legacy pesticides in salmon habitat in British Columbia, Canada. Environ Toxicol Chem 27:2253-2262.

Health Canada, 2007. Pesticides and Health. https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/contaminants/pesticides-eng.pdf. Accessed in May 2024. 

Health Canada, 2010. Polychlorinated biphenyls. https://www.canada.ca/en/health-canada/services/chemical-substances/fact-sheets/chemicals-glance/polychlorinated-biphenyls.html. Accessed in May 2024. 

Health Canada, 2011. Discontinuation of endosulfan. https://publications.gc.ca/collections/collection_2011/sc-hc/H113-5-2011-1-eng.pdf. Accessed in May 2024.

Health Canada, 2016. Special review of simazine: proposed decision for consultation. https://publications.gc.ca/collections/collection_2016/sc-hc/H113-5-2016-9-eng.pdf. Accessed in May 2024.

Marvin, C. H., Berthiaume, A., Burniston, D. A., Chibwe, L., Dove, A., Evans, M., … & Tomy, G. T. (2021). Polycyclic aromatic compounds in the Canadian Environment: Aquatic and terrestrial environments. Environmental Pollution, 285, 117442.

Morales-Caselles, C., Yunker, M.B., and Ross, P.S. 2017. Identification of spilled oil from the MV Marathassa (Vancouver, Canada 2015) using alkyl PAH isomer ratios. Archives of Environmental Contamination and Toxicology 73: 118-130.

Lo, B. P., Marlatt, V. M., Liao, X., Reger, S., Gallilee, C., Ross, A. R. S., Brown, T. M. (2023). Acute Toxicity of 6PPD-Quinone to Early Life Stage Juvenile Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) Salmon. Environmental Toxicology and Chemistry, 42(4), 741-947. 

Morales-Caselles, C., Yunker, M.B., and Ross, P.S. 2017. Identification of spilled oil from the MV Marathassa (Vancouver, Canada 2015) using alkyl PAH isomer ratios. Archives of Environmental Contamination and Toxicology 73: 118-130.

Noël, M., Dangerfield, N., Hourston, R. A., Belzer, W., Shaw, P., Yunker, M. B., & Ross, P. S. (2009). Do trans-Pacific air masses deliver PBDEs to coastal British Columbia, Canada?. Environmental Pollution, 157(12), 3404-3412.

Othman, N., Ismail, Z., Selamat, M. I., Sheikh Abdul Kadir, S. H., & Shibraumalisi, N. A. (2022). A review of polychlorinated biphenyls (PCBs) pollution in the air: where and how much are we exposed to? International Journal of Environmental Research and Public Health, 19(21), 13923.

Ross, P. S., Ellis, G. M., Ikonomou, M. G., Barrett-Lennard, L. G., & Addison, R. F. (2000). High PCB concentrations in free-ranging Pacific killer whales, Orcinus orca: effects of age, sex and dietary preference. Marine Pollution Bulletin, 40(6), 504-515.

Schulz, R. (2004). Field studies on exposure, effects, and risk mitigation of aquatic nonpoint‐source insecticide pollution: A review. Journal of environmental quality, 33(2), 419-448.

Tian et al. (2021). A ubiquitous tire rubber–derived chemical induces acute mortality in coho salmon. Science 371,185-189. DOI:10.1126/science.abd6951

UNEP. 2025. United Nations Environment Programme: Stockholm Convention on Persistent Organic Pollutants. Accessed June 2025: https://www.pops.int/partners/unep/overview/tabid/255/default.aspx

van Elsas, J.D., Semenov, A.V., Costa, R., Trevors, J.T. Survival of Escherichia coli in the environment: fundamental and public health aspects, The ISME Journal, Volume 5, Issue 2, February 2011, Pages 173–183, https://doi.org/10.1038/ismej.2010.80

van Stempvoort, D.L., Brown, S.J. Spoelstra, J., Garda, D., Robertson, W.D., and Smyth, S.A.. 2020. Variable persistence of artificial sweeteners during wastewater treatment: Implications for future use as tracers. Water Research 184: 116124. https://doi.org/10.1016/j.watres.2020.116124.