Juvenile chinook salmon in the Fraser River estuary have been found to contain a range of chemicals, including pharmaceuticals and flame retardants, according to a recent study. Researchers gathered samples from hundreds of fish over a two-year period and identified over 80 contaminants in the salmon tissue alone, with the likely source being industrial and wastewater sites upstream. Water samples from the salmon habitat revealed 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 presence of pollutants such as pharmaceuticals, personal care products, pesticides, and flame retardants in the fish.
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, including cocaine and pesticides, were detected in habitat water samples. Eight “watchlist” chemicals posing biological risks were also found in salmon tissue samples, comprising pesticides, pharmaceuticals, and other organic chemicals.
Funded largely by the Department of Fisheries and Oceans, the study was conducted in collaboration with the Raincoast Conservation Foundation and Simon Fraser University. Tanya Brown, a study co-author and assistant professor at Simon Fraser University, emphasized the need for further monitoring, as there may be additional unexamined chemicals affecting the fish.
Similar research has been conducted in Washington state’s Puget Sound, where contaminants in fish habitat have been monitored for over three decades. Molly Shuman-Goodier, a research scientist with the Washington Department of Fish and Wildlife, highlighted the inhibitory effects of synthetic organic chemicals on chinook growth and the potential long-term impacts on salmon populations.
The study’s findings have implications for marine mammals like southern resident killer whales, which feed on chinook salmon. These killer whales have some of the highest contaminant levels among marine mammals. The presence of organic chemicals in Puget Sound chinook exceeded human health thresholds set by the Washington State Department of Health.
Researchers on both sides of the border suggest that the study could influence chemical management practices, whether through public policies or individual actions. Brown emphasized the importance of responsible pharmaceutical disposal at the individual level, given the detection of high-priority pharmaceuticals in the study.