title: Polychlorinated biphenyls still pose significant health risks to northwest Atlantic harbor seals.
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 the 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 ∑30PCB concentrations (overall mean±standard deviation: 76,860±111,800 ng/g lipid weight, lw) were higher than blubber concentrations (48,180±69,420 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 Kow), but heavier PCBs may be efficiently transferred during late lactation from mother to pup liver. Biomagnification factors (BMFs) for ∑6PCBs from prey fish to adult male seals ranged from 90 to 547 in the liver and 88 to 532 in the blubber, and suggested that molecular structure and metabolic capacity were more important influences than log Kow on the retention of PCBs. Blubber concentrations of ∑30PCBs in 87% of the pups were an order of magnitude higher than recent toxic reference values (TRVs) calculated for ∑154PCBs 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.
authors.affiliation: Marine Environmental Research Institute, Center for Marine Studies, P.O. Box 1652, Blue Hill, ME 04614, USA; Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, P.O. Box 509, Albany, NY 12201-0509, USA. Electronic address: sshaw@meriresearch.org.
authors.forename: Susan D
authors.initials: SD
authors.lastname: Shaw
authors.affiliation: Marine Environmental Research Institute, Center for Marine Studies, P.O. Box 1652, Blue Hill, ME 04614, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Berger
authors.affiliation: Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Weijs
authors.affiliation: Eurofins-ERGO, Neuländerkamp 1, 21079 Hamburg, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Päpke
authors.affiliation: Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Adrian
authors.initials: A
authors.lastname: Covaci
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D004784:Environmental Monitoring; D005260:Female; D008297:Male; D009511:New England; D046049:Phoca / Q000378:metabolism*; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Biomagnification/biotransformation; Lactational transfer; Metabolism; PCB congeners; Seal epizootics; Sublethal effects