Aiding salmon recovery by uncovering sources of toxic chemicals

Toxics researcher Alex Gipe collects samples from the Snohomish River to detect sources of flame retardants.

New research sheds light on how toxic flame retardants, known as PBDEs, accumulate in the Snohomish River watershed and threaten juvenile Chinook salmon—a key food source for endangered orcas.

Washington Department of Ecology | April 23, 2025

Spring is here, and tiny, young Chinook salmon will begin their incredible journey from the Snohomish River to the ocean. The young salmon are making their way downstream, swimming fast, passing towns…they are ocean-bound. 

Their journey is not an easy one. They face many challenges, from natural causes like predation or competition for food to human causes like pollution, including toxic chemicals.

One group of toxic chemicals called polybrominated diphenyl ethers – or PBDEs – are known to affect the health and survival of juvenile Chinook salmon. 

PBDEs are a group of flame retardants used in furniture, car seats, electronics, plastics, and children’s toys to meet fire safety standards. These chemicals remain in the environment for a long time, eventually building up in food webs and making their way from Chinook salmon to endangered orca whales that eat salmon. 

But how do the chemicals make their way into the bodies of Chinook salmon?

To answer this question, we studied how PBDEs flow through and accumulate in the Snohomish River watershed. We published our findings in a report titled “Assessing Sources of Toxic Chemicals Impacting Juvenile Chinook Salmon.”