Uptake of aromatic and chlorinated hydrocarbons by juvenile chinook salmon (Oncorhynchus tshawytscha) in an urban estuary

A study was conducted to assess the potential for uptake of toxic chemicals by down-stream migrant salmon in an urban estuary. Juvenile chinook salmon (Oncorhynchus tshawytscha) were collected from the Duwamish Waterway (located in Seattle, Washington) and from the Nisqually River (a reference site). The mean concentrations of aromatic hydrocarbons and polychlorinated biphenyls (PCBs) in the stomach contents (food organisms) of salmon from the Duwamish Waterway were approximately 650 times and 4 times, respectively, higher than those in salmon from the Nisqually River. Similarly, the mean concentration of bile metabolites of aromatic compounds which fluoresce at benzo[a]pyrene wavelengths was 24 times higher in the urban salmon compared to the reference salmon, whereas the mean concentration of PCBs in liver of urban salmon was 3 times higher than that in reference salmon. The study clearly demonstrated that, during their residency in this urban estuary, juvenile chinook salmon bioaccumulate substantial levels of toxic chemicals. The possible effects of these chemical exposures on the health and survival of this species are not presently known.