Remote locations, such as the Arctic, are often sinks for persistent contaminants which can ultimately bioaccumulate in local wildlife. Assessing temporal contaminant trends in the Arctic is important in understanding whether restrictions on legacy persistent organic pollutants (POPs) have led to concentration declines. Beluga whale (Delphinapterus leucas) tissue samples were collected from two subpopulations (Cook Inlet, Alaska and the eastern Chukchi Sea) between 1989 and 2006. Several POPs (i.e., polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethane and related compounds (DDTs), chlordanes, hexachlorocyclohexanes (HCHs), pentachlorobenzene, mirex, heptachlor epoxide, and polybrominated diphenyl ethers (PBDEs)) were measured in blubber from 70 individual animals and mercury (Hg) was measured in liver from 68 of those individuals. Legacy POPs (PCBs, chlordanes, DDTs, and HCHs) were the predominant organic compound classes in both subpopulations, with overall median concentrations of 2190 ng/g lipid and 1830 ng/g lipid for PCBs (sum of 80 congeners) and DDTs (sum of 6 DDT-related compounds), respectively. PCBs, DDTs, chlordanes, pentachlorobenzene, heptachlor epoxide, and Hg were significantly (p < 0.05) higher in the eastern Chukchi Sea belugas than belugas from Cook Inlet. In contrast, eastern Chukchi Sea belugas were significantly lower in PBDE concentrations than belugas from Cook Inlet (p < 0.0001). Overall, a significant temporal increase in blubber tissue concentrations for both Cook Inlet and the eastern Chukchi Sea belugas was seen only for PBDEs (sum of 8 congeners) (p=0.0012 and p < 0.0001, respectively). Aside from a decreasing temporal trend of HCHs (p=0.011) in eastern Chukchi Sea belugas, significant temporal decreases in the legacy POPs were not observed, indicating either a lagging response of the Arctic to source reductions or the maintenance of concentrations by unregulated sources.
Citation: Science of the Total Environment
Pub Type: Journals
Persistent organic contaminants, Arctic, Alaska, Beluga whale, Temporal trends