Organochlorine exposure and bioaccumulation in the endangered Northwest Atlantic right whale (Eubalaena glacialis) population

Abstract Exposure to toxicants is one factor hypothesized to influence population growth of the northern right whale. Organo-chlorines in right whale skin, feces, and prey were measured and used to identify factors influencing exposure and bioaccumulation. Concentrations of 30 polychlorinated biphenyls (PCBs) (5.7 ± 8.9 μg/g lipid) and 20 pesticides (11.4 ± 15.4 μg/g lipid) in skin biopsies were consistent with other baleenopterids. Concentrations in feces and prey were two orders of magnitude less than in biopsies. In principal component analysis, organochlorines in biopsies matched those from Bay of Fundy, Canada, zooplankton, whereas feces were like Cape Cod, USA, copepods. Year of biopsy collection was the principal factor associated with differential accumulation of nonmetabolizable PCBs, 4,4′-DDE, and dieldrin. Biopsies collected during winter had lower concentrations of lipid and metabolizable compounds than biopsies collected during summer. Concentrations of metabolizable PCBs increased with age in males. The bioaccumulation patterns implied that blubber burdens change annually because of the ingestion of different prey or prey from distinct locations and the release of some organochlorines stored in blubber during lipid depletion in winter. Because biopsy concentrations were lower than those found in marine mammals affected by PCBs and DDTs, we do not have evidence that the endangered whales bioaccumulate hazardous concentrations of organochlorines.