PCB-related exposure and effects in ringed seals (Pusa hispida) frequenting a locally-contaminated marine environment in Labrador

Supervisory Committee Dr Caren C. Helbing (Department of Biochemistry and Microbiology) Supervisor Dr Caroline E. Cameron (Department of Biochemistry and Microbiology) Departmental Member Dr Juan Ausio (Department of Biochemistry and Microbiology) Departmental Member Dr Robie W. Macdonald (School of Earth and Ocean Sciences) Outside Member Dr Ken J. Reimer (Royal Military College of Canada, Department of Chemistry and Chemical Engineering) Additional Member The release of 260 kg of polychlorinated biphenyls (PCBs) by a military radar station into Saglek Bay (Labrador) in the eastern Canadian Arctic contaminated adjacent marine sediments, and some fish, seabirds, and ringed seals. However, attributing the PCBs found in high trophic level and highly mobile marine mammals to any point source is, in most cases, impossible. This thesis demonstrated the extent to which a local PCB source at Saglek Bay led to the contamination and health effects in ringed seals. The dominance of PCBs at this contaminated marine site afforded a unique opportunity to evaluate the effects of this single class of industrial chemical in a manner that has not been previously possible in marine mammals. We used a variety of tools to characterize the contribution of local PCB contamination in the Labrador ringed seal food web. These tools included: 1) univariate and multivariate statistical exploration of contaminant patterns; 2) stable isotope ratios and fatty acid