Identifying sources of polychlorinated biphenyls to the Southern Resident killer whales within the Salish Sea using passive sampling and chemical activity analysis

One of the main threats to the endangered Southern Resident killer whale population is environmental contaminants. Among the contaminants of greatest concern are polychlorinated biphenyls (PCBs), a legacy persistent organic pollutant. Recent studies suggest that PCBs are still being released into the environment today. The objective of this study is to determine sources of PCBs to the killer whales. Passive sampling of air and water was used to measure current levels of PCBs and combined with concentration data of PCBs in sediment and biota in a chemical activity analysis. The results identify a number of local sources of PCBs to air, but that overall PCBs in the atmosphere are not a source to the Salish Sea. The study illustrates the application of passive sampling and chemical activity analysis as a useful approach to link sources of PCBs to the body burdens of PCBs in salmon and killer whales.