PARENT SESSION
PW7 - Biotransformation / Metabolisms / Degradation
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P790) Methyl Sulfone and Hydroxylated PCB Metabolites in Blood Versus Adipose of Greenland Polar Bears.

Sandala, Greg¹, Sonne-Hansen, Christian², Muir, Derek³, Dietz, Rune², Bennett, Erin¹, Letcher, Robert^*,1, ¹ Great Lakes Institute, University of Windsor, Windsor, Ontario, Canada² National Environmental Research Institute, Dept. of Arctic Environment, Roskilde, Denmark³ Environment Canada, Burlington, Ontario, Canada

ABSTRACT- Persistent methyl sulfone (MeSO₂) PCB metabolites are major contaminant residues in polar bear (Ursus maritimus) from the Canadian Arctic. In Canadian and Norwegian populations of polar bear, OH-PCB metabolites have also been identified in blood. These PCB metabolites are potentially estrogenic and/or thyroidogenic disrupting active. In the present study, the congener patterns and relative importance (formation, mobilization, etc.) of the two PCB metabolite classes versus the parent PCBs was investigated in polar bears from Scoresby Sound area of Eastern Greenland. In polar bear adipose samples (n = 19), 42 PCB congeners and 20 MeSO₂-PCBs were determined. In whole blood, 21 OH-PCB congeners were determined in addition to PCBs and MeSO₂-PCBs. Regardless of age and sex, in both adipose and blood the MeSO₂-PCB congener pattern was dominated by 3'- and 4'- MeSO₂-CB49, -CB101 and CB87, and 4- MeSO₂-CB149 (about 70% of the sum () MeSO₂-PCBs). Overall differences in the MeSO₂-PCB congener pattern between blood and adipose were observed, which suggests a possible dependency of mobilization and/or deposition on metabolite structure. -MeSO₂-PCB concentrations ranged from 125 to 4000 ng/g (lipid weight) and 4 to 52 ng/g (wet weight) in the adipose and blood, respectively, whereas the -PCB concentrations were 2800 to 19000 ng/g (lipid weight) and 39 to 256 ng/g (wet weight), respectively. In the whole blood (n = 5), the -PCB, -OH-PCB and -MeSO₂-PCB concentrations ranged from 39 to 256, 90 to 313, and 4 to 52 ng/g (wet weight), respectively. To our knowledge, this is the first study to examine in a wildlife species the relative importance of MeSO₂-PCB and OH-PCB metabolite formation and PCBs in the blood versus adipose tissue.

Key words: PCB metabolites, polar bear, Greenland, blood and adipose