Environmental contaminants in wild mink in the Northwest Territories, Canada

• Published in: The Science of the total environment 1995-01, Vol.160-161, p.473-486
• Main Authors: Poole, K.G., Elkin, B.T., Bethke, R.W.
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Carnivora - metabolism; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; Environmental Pollutants - metabolism; Freshwater; Fundamental and applied biological sciences. Psychology; Heavy metals; Hydrocarbons, Chlorinated - metabolism; Mammalia; Metals - metabolism; Mink; Mink - metabolism; Mustela vison; Northwest Territories; Organochlorines; Polychlorinated biphenyls; Polychlorinated Biphenyls - metabolism; Seasons
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/0048-9697(95)04381-A

As a top trophic level species that readily bioaccumulates environmental pollutants, the mink (Mustela vison) is considered to be a sensitive indicator of ecosystem health. Here we report on the first 2 years of a 4-year program established to examine organochlorine and heavy metal residues in wild mink from western Northwest Territories (NWT), Canada. Tissue samples taken from up to 24 mink harvested from each of five sites in 1991-92 and 1992-93 were analyzed for residues of a suite of 63 organochlorines in fat and liver samples, including 43 polychlorinated biphenyl (PCB) congeners and 20 pesticides, and residues of 10 heavy metals in liver and kidney samples. Overall, contaminant levels were low in comparison with level in other mink studied in North America. ΣPCB residues (sum of 43 congeners) ranged from a mean of 5.32 ng/g wet weight in the livers of Inuvik mink (the most northerly collection site) to 27.67 ng/g in mink from Fort Smith (the most southerly collection site). There appeared to be no differences in organochlorine burden between sexes. Heavy metal residues were also comparatively low, with the exception of total mercury, which was at moderate levels (community means of 1.16-3.30 μg/g wet wt. in liver samples). There was a distinct trend of decreasing organochlorine contaminant burdens with increasing latitude, but no trend in heavy metal burdens was evident. There was a doubling of mean ΣPCB levels in Inuvik mink from 5.32 ng/g wet weight in 1991-92 to 10.69 ng/g in 1992-93. Population indices derived from age and sex ratios of the harvest, coupled with comparatively low levels of contaminants, suggest little or no effects on mink reproduction or population health as a result of these contaminants. Long-range atmospheric transport is probably the major source of most of the contaminants. Additional collections will further elucidate spatial and temporal trends in contaminant levels in NWT mink.