Juvenile chinook salmon in the Fraser River estuary have been found to contain a variety of chemicals, including pharmaceuticals and flame retardants, according to a recent study. Researchers collected samples from hundreds of fish over a two-year period and identified more than 80 contaminants in the salmon tissue alone, with the main sources believed to be industrial and wastewater sites upstream. Water samples from salmon habitat were also analyzed, revealing the presence of 130 contaminants.
The research team expressed concerns that these chemicals could be negatively impacting the growth, behavior, and overall health of the chinook salmon. David Scott, the lower Fraser research and restoration director for the Raincoast Conservation Foundation (RCF), highlighted the broad range of pollutants discovered in the study, ranging from pharmaceuticals and personal care products to pesticides and flame retardants.
The study, which focused on organic chemicals, identified 16 priority contaminants with potential adverse effects, including PBDE-penta-total, a flame retardant found in salmon tissue samples. Additionally, 15 other priority contaminants, such as cocaine and pesticides, were detected in habitat water samples. Eight more “watchlist” chemicals posing elevated biological risks were found in salmon tissue samples, including pesticides, pharmaceuticals, and other organic chemicals.
Funded primarily by the Department of Fisheries and Oceans and conducted in collaboration with the RCF and Simon Fraser University, the study also emphasized the likelihood of additional unmeasured chemicals affecting the fish. Tanya Brown, a study co-author and assistant professor at Simon Fraser University, stressed the alarming combination of chemicals to which the fish are exposed, citing the vast number of high-volume use chemicals in the marketplace.
Similar research in Washington state’s Puget Sound has shown that synthetic organic chemicals may inhibit chinook growth, potentially leading to long-term impacts on the salmon population. Molly Shuman-Goodier, a research scientist with the Washington Department of Fish and Wildlife, highlighted the importance of documenting these effects in the field to understand their implications on salmon growth and return rates.
Furthermore, concerns were raised about the impact on marine mammals, particularly southern resident killer whales that feed on chinook salmon. These whales have some of the highest contaminant loads among marine mammals. The study’s findings may influence the management of chemicals through public policies and individual actions, such as proper disposal of pharmaceuticals to mitigate environmental impacts.