Predicted polybrominated diphenyl ether (PBDE) and polychlorinated biphenyl (PCB) accumulation in southern resident killer whales

摘要

ABSTRACT: Persistent organic pollutants (POPs) are anthropogenic contaminants that bioaccumulate in upper trophic level species. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are POPs of particular concern because they can induce immunotoxicity, neurotoxicity, and reproductive impairment. Killer whales Orcinus orca can accumulate high concentrations of POPs because they are long-lived apex predators. Southern resident killer whales (SRKWs) are an endangered fish-eating population that consists of 3 pods (J, K, and L) with a geographic range from central California, USA, to the Queen Charlotte Islands, Canada. An individual-based modeling approach was used to predict the accumulation of sum PBDEs (ΣPBDEs) and sum PCBs (ΣPCBs) in specific individuals in the SRKW population. Model predictions for the current concentrations corresponded closely to the concentrations measured in biopsies collected from known individuals. The predicted ΣPBDE concentrations over the life-span of individual killer whales were consistent with a doubling time of ~3 to 4 yr, highlighting the rapid emergence of PBDEs as a priority concern in these animals. J pod individuals had the highest predicted ΣPBDE and ΣPCB concentrations, likely due to their increased residence time near industrial centers. Modeled historical ΣPCB concentrations did not increase substantially over time or with age in males born after 1970, whereas the ΣPBDE concentrations increased over time and with age. In general, modeled future projections indicated that the average male and female had similar ΣPBDE trends with age, time, and diet scenario. Future ΣPCBs are predicted to slowly decline; however, SRKWs will continue to be exposed for several generations.