Shaw, SD, Berger, ML, Weijs, L Päpke, O, Covaci, A. (2014). Polychlorinated Biphenyls Still Pose Significant Health Risks to Northwest Atlantic Harbor Seals. Science of the Total Environment, 27 May 2014, 10.1016/j.scitotenv.2014.05.011

Abstract:

Polychlorinated biphenyls (PCBs) have been detected at relatively high concentrations in harbor seals, apex predators in the northwest Atlantic. As part of an ongoing assessment of the effects of PCBs on population health, we analyzed tri- to deca-PCBs in liver of 56 harbor seals (6 adult males, 50 pups) and in 11 blubber samples (4 adult males, 7 pups) and examined tissue-specific accumulation patterns, biomagnification potential, and toxic implications of current PCB concentrations. Hepatic Σ₃₀PCB concentrations (overall mean ± standard deviation: 76860 ± 111800 ng/g lipid weight, lw) were higher than blubber concentrations (48180 ± 69420 ng/g lw). Regional trends were suggestive of fresh PCB inputs from the industrialized, densely populated southern coast of New England versus the rural north. The lack of temporal trends confirmed that tissue concentrations of PCBs have plateaued since the early 1990s. Tissue distribution of PCBs varied significantly by age and, surprisingly by gender among the pups. Principal component analysis (PCA) revealed that lighter PCBs are selectively transferred from mother to pup blubber in relation to lipid solubility (log K_ow), but heavier PCBs may be efficiently transferred during late lactation from mother to pup liver. Biomagnification factors (BMFs) for Σ₆PCBs from prey fish to adult male seals ranged from 90 to 547 in liver and 88 to 532 in blubber, and suggested that molecular structure and metabolic capacity were more important influences than log K_ow on the retention of PCBs. Blubber concentrations of Σ₃₀PCBs in 87% of the pups were an order of magnitude higher than recent toxic reference values (TRVs) calculated for Σ₁₅₄PCBs in nursing harbor seals, suggesting that the pups are at risk for PCB-mediated toxicity at a vulnerable stage of development. Given the recurring pattern of epizootics in these seals, the health of the population is of concern.