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TitleRecent trends and source(s) of atmospheric Pb deposition in the Canadian High Arctic documented from ice cores and lake sediments
AuthorZdanowicz, C; Shotyk, W; Zheng, J; Krachler, M; Outridge, P; Stern, G; Fisher, D
SourceNorthern Contaminants Program Results Workshop, Program with abstracts; 2005, 1 pages
Alt SeriesEarth Sciences Sector, Contribution Series 20080620
MeetingNorthern Contaminants Program Results Workshop; Victoria, B.C.; CA; September 27 - 29, 2005
NTS48E; 48F; 48G; 48H; 58E; 58H
AreaDevon Island; Devon ice cap
Lat/Long WENS-92.0000 -80.0000 76.0000 74.0000
Subjectsenvironmental geology; surficial geology/geomorphology; snow; ice; ice conditions; core analysis; cores; pollutants; pollution; lead; heavy metals contamination; environmental studies; environmental impacts
AbstractSnow and glacial ice samples as well as lake sediment cores from the Canadian High Arctic were analyzed for Pb content and isotopic ratios in order to test the reliability of these natural archives that are widely used to quantify atmospheric metal inputs to northern environments. Lead concentrations, enrichment factors and isotopic ratios in ancient ice strata and modern snow from the Devon Ice Cap (Devon Island, 1830 masl) reveal that anthropogenic Pb inputs have dominated atmospheric deposition at this site since well before the 1923 introduction of Pb-alkyl additives in gasoline, and continue to dominate to the present day. Furthermore, the post-1850 depositional history of Pb in the Ice Cap differs from that on central Greenland by a slower post-1970 decline, suggesting that the Canadian High Arctic continues to receive some atmospheric Pb from sources other than those (predominantly North American) affecting Greenland. These other sources are most probably of Eurasian origin. In contrast to the high-altitude glacial ice and snow record, Pb profiles in two coastal lake sediments from Cornwallis and Devon Islands show no detectable inputs of anthropogenic Pb, either in terms of recent concentration increases or shifts in the Pb isotopic composition. Reasons for this discrepancy will be discussed.