Bioaccumulation of PCBs in Southern Resident Killer Whales in the Salish Sea

Chemical contaminants are a threat to Southern Resident Killer Whales (SRKW). The contribution of polychlorinated biphenyls (PCBs) in local sediments to the bioaccumulation of PCBs in SRKW was investigated. The temporal and spatial trends of concentrations of PCBs in sediment, Chinook salmon and SRKW were assessed. The half – lives of PCBs were estimated using a food web bioaccumulation model and the concentrations of PCBs in Chinook salmon and SRKW were estimated using Biota Sediment Accumulation Factors. There were no significant temporal declines in the concentrations of PCBs in sediment, Chinook salmon or SRKW as would be expected given the half – lives. The concentrations of PCBs in sediment could bioaccumulate to the levels observed in SRKW. Some similarities in the PCB congener composition were observed in sediment, salmon and SRKW. The results suggest that local environmental sources of PCBs in the Salish Sea could contribute to the PCBs observed in SRKW.