Title

Xenobiotic-metabolizing enzymes and biotransformation of polybrominated diphenyl ether and polychlorinated biphenyl contaminants in beluga whales (Delphinapterus leucas) from the St. Lawrence River estuary and western Hudson Bay, Canada.

Date of Award

2004

Degree Type

Thesis

Degree Name

M.Sc.

Department

Chemistry and Biochemistry

First Advisor

Letcher, Robert,

Keywords

Environmental Sciences.

Rights

CC BY-NC-ND 4.0

Abstract

The highly contaminated St. Lawrence Estuary beluga whale (SLB) population exhibits health problems and various pathologies possibly associated with pollutant exposure, which are not found in less exposed Canadian Arctic belugas (CAB). Biotransformation mediates contaminant fate and effects through conversion to less persistent, more excretable products (detoxification) and through formation of retained/persistent, secondary contaminants (bioactivation). In this thesis, the metabolic potential of these two differentially exposed beluga populations towards PCBs and PBDEs was investigated. Qualitatively similar hepatic xenobiotic-metabolizing enzyme profiles (cytochromes P4501A, 2B, 3A, 2E, epoxide hydrolase and UDP-glucuronosyl transferase) were immunochemically detected between SLB and CAB, indicating that CAB can be used to model contaminant biotransformation in the endangered SLB. The results suggest contaminant bioactivation through formation of retained/persistent and potentially toxic PCB (and possibly PBDE) metabolites. Evidence of possible bioactivation mechanisms via biotransformation supports the association between contaminant exposure and health problems in the endangered SLB population. (Abstract shortened by UMI.)Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .M355. Source: Masters Abstracts International, Volume: 43-05, page: 1689. Adviser: Robert Letcher. Thesis (M.Sc.)--University of Windsor (Canada), 2004.