Temporal trends in “legacy” organochlorine contaminants in blubber of ringed seals (Phoca hispida) from Ulukhaktok, NT, Canada between 1972 and 2010

• Published in: The Science of the total environment Vol. 466-467; pp. 564 - 576
• Main Authors: Addison, R.F., Muir, D.C., Ikonomou, M.G., Harwood, L., Smith, T.G., Alikamik, J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2014
• Subjects: Adipose Tissue - chemistry; Animals; Arctic; Arctic Regions; Chromatography, Gas; Environmental Exposure; Environmental Monitoring; Female; Hydrocarbons, Chlorinated - metabolism; Insecticides - metabolism; Male; Northwest Territories; Organochlorines; Persistent; Phoca - metabolism; Polychlorinated Biphenyls - metabolism; Ringed seals; Seasons; Trend; Water Pollutants, Chemical - metabolism; Northwest Territories; Arctic Regions; Trend; Persistent; Arctic; Ringed seals; Organochlorines
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2013.07.079

In blubber of ringed seals (Phoca hispida) from Ulukhaktok, NT, residues of DDT, other organochlorine pesticides, and PCBs declined between 1972 and 2010. The rate of decline varied: concentrations of the DDT-group began to fall after 1981, whereas those of PCBs fell rapidly between 1972 and 1981, and then slowed. Concentrations of cis- and trans-chlordane and of HCB in both sexes, and of cis-nonachlor in males, declined slowly between 1978 and 2010; those of other organochlorine pesticides remained steady. Exponential half-lives of p,p′-DDT and p,p′-DDE in female seals are about 9 and 36y (corresponding to initial declines of 7.8% and 1.9% per year, respectively) and those of PCB congeners from about 20 to 60y (declines of 3.2% to <1.5% per year); the more refractory residues may be detectable for centuries to come. Exploratory PCA of PCB congener distribution identified temporal changes apparently not related to molecular structure. •This is an analysis of the longest available time-series of POPs in Arctic seals (38y).•Levels of DDT did not change between 1972 and 1981, but then began to decline.•PCB levels fell rapidly between 1972 and 1981, and then declined more slowly.•Levels of some minor organochlorine pesticides have been steady since 1978.•Some refractory residues will probably persist in Arctic seals for centuries.