Salmon spend a portion of their early life history in freshwater streams and rivers. Research in the Green and Lower Duwamish rivers and in the urban streams of Puget Sound has demonstrated that salmon there are exposed to and affected by toxic contaminants from road runoff and other sources. These toxic contaminants may adversely impact salmon health and reduce their overall survival. Because no information on contaminant tissue concentrations of juvenile salmon is available for Water Resource Inventory Areas (WRIAs) 7 and 8, this effort will help fill a significant data gap and provide a baseline to build our knowledge of how juvenile salmon, specifically coho (Oncorhynchus kisutch), in these watersheds might be impacted by toxic chemicals.

A combination of electrofishing by backpack or cataraft, dip nets, and minnow traps will be used to sample juvenile coho salmon at targeted locations in the tributaries of WRIAs 7 and 8 between July and October 2020. The King County Environmental Lab will analyze all coho tissue samples. Chemicals targeted for analysis will include chlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFAS), and mercury.