PARENT SESSION
SP8 - Environmental Contaminants in Marine Mammals
Chair: Krahn, Margaret¹, ¹ 2725 Montlake Boulevard East, Seattle, WA, USA
Co-chair: Kucklick, John², ² 219 Fort Johnson Road, Charleston, SC, USA
2:10 PM to 5:30 PM - Sunday, 17 November 2002
Room Ballroom C

(145) Halogenated Phenolic Pollutants and Metabolites in the Killer Whale (Orcinus orca).

Bennett, Erin^*,1, Ross, Peter², Letcher, Robert¹, ¹ Great Lakes Institute, University of Windsor, Windsor, Ontario, Canada² Institute of Ocean Science, Dept Of Contaminant Sciences, Sidney, British Columbia, Canada

ABSTRACT- It has been shown that polyhalogenated aromatic hydrocarbon (PHAH) contaminants are potentially toxic and accumulate in the large lipid reserves of mammals, especially marine mammals. However, PHAHs, such as PCBs, are biotransformed to retained or persistent metabolites, in some cases with appreciable biological half-lives. For example, persistent aryl sulfone PCB (MeSO₂-PCB) and retained hydroxylated PCB (OH-PCB) have been reported in marine mammals, but there is no data on these compounds in killer whale (Orcinus orca). The objective of this study was to determine the levels of PHAH metabolites in a single blood sample collected from a killer whale as they relate to their parent compounds. The blood sample was collected from an adult female killer whale, that was held in captivity at the Vancouver Aquarium Marine Science Centre, British Columbia, Canada, which had been fed a diet of wild Pacific herring (Clupea pallasi). The sample was extracted and analyzed for PCBs, organochlorine pesticides (OCs), MeSO₂-PCBs, OH-PCBs and 4-OH-HpCS (a metabolite of octachlorostyrene and pentachlorophenol). Of the analytes detected (w/w), PCBs (12.5 ng/g) were the major contaminant followed by DDTs (2.87 ng/g) and OH-PCBs (2.04 ng/g). The PCB congener pattern in blood was similar to patterns previously observed in blubber biopsies collected from free-ranging killer whales in British Columbia. These results suggest that certain PCBs are selectively retained, irrespective of dietary patterns, and blood may be a useful surrogate tissue for measuring PCBs in killer whale. To our knowledge, this is the first report on PCB and other PHAH metabolites in the blood of killer whales. Assuming there is no accumulation from the fish diet, our results indicate that killer whales are able to form OH-PCB and 4-OH-HpCS metabolites. The presence of high levels of these metabolites may present health risks to free-ranging killer whales since these compounds have been shown to elicit estrogenic and thyroidogenic effects

Key words: Killer Whale, PCBs, Biotransformation, OH-PCBs