Web Release Date: February 23,
Enantiomer-Specific Accumulation of PCB Atropisomers in the Bowhead Whale (Balaena mysticetus)
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Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6, Department of Wildlife Management, North Slope Borough, Barrow, Alaska 99723, and Environment Canada, National Water Research Institute, Burlington, Ontario, Canada L7R 4A6
Received for review October 25, 2001
Revised manuscript received January 16, 2002
Accepted January 24, 2002
Abstract:
Blubber (n = 40) and liver (n = 20) samples from the bowhead whale (Balaena mysticetus) were collected during the 1997-1998 Native (Inuit) subsistence harvests in Barrow, AK. Bowhead tissues and zooplankton were analyzed for polychlorinated biphenyl (PCB) concentrations and the enantiomeric fractions (EFs) of eight chiral PCB congeners (PCB-91, 95, 135, 136, 149, 174, 176, and 183) to quantify the enantiomer-specific accumulation of PCBs in this cetacean. PCB concentrations in bowhead blubber were low (mean ± 1 SE: 610 ± 54 ng g-1 lipid) relative to other cetaceans. The accumulation of several chiral PCBs (PCB-91, 135, 149, 174, 176, and 183) in bowhead blubber was enantiomer-specific relative to bowhead liver and zooplankton, suggesting that biotransformation processes within the bowhead whale are enantioselective. The EFs for PCB-95 and 149 were significantly correlated with body length in male and female whales, while EFs for PCB-91 correlated with length in males only. Despite evidence for enantioselective biotransformation, all three congeners bioaccumulated in the bowhead relative to PCB-153. Results suggest that enantioselective accumulation of PCB-91, 95, and 149 is influenced by PCB concentrations, age, and/or the modification of an uncharacterized stereoselective process (or processes) during sexual maturity.
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