Monitoring toxic contaminants

Juvenile coho or cutthroat trout
Photo by WDFW

Aquatic life in Puget Sound is exposed to thousands of chemicals that can affect their health, reproduction, and survival. Nearly all of these toxic chemicals can be classified into two main types: persistent organic pollutants (POPs), which do not easily break down in the environment, are able to travel long distances, and accumulate up the food web; or contaminants of emerging concern(CECs), which are not currently regulated and include chemicals such as pharmaceuticals, personal care products, cleaners, and agricultural compounds, and whose impacts may not yet be fully known.

TBiOS conducts routine monitoring of toxic contaminants in indicator species to help identify areas of greatest exposure, track trends over time, determine if cleanup efforts are effective, and identify what types of contamination remain a concern for health. The four main habitat types studied include river estuaries, the nearshore, benthic (seafloor), and pelagic (open water).

In the river estuaries, we monitor seaward migrating juvenile Chinook salmon. Contaminants found in juvenile salmon represent in-river exposure as well as contaminant exposure while rearing in the estuary. Estuaries represent the interface between salt and fresh water, and are frequently surrounded by highly developed areas. 

Nearshore habitats are monitored using caged native bay mussels every two years. This habitat is an area of high primary productivity, and also an area with high contaminant inflow through sources such as stormwater and river inputs. 

Benthic habitats are monitored using English sole, with monitoring studies done every two years. Many persistent organic pollutants accumulate in sediments, making English sole a good indicator for analyzing the success of cleanup efforts.

In pelagic areas, adult Chinook salmon (both returning and resident Blackmouth) are monitored, as is Pacific herring. This habitat is known to have high PCB concentrations, and monitoring is critical in helping inform seafood safety.