CGRG Bibliography of Canadian Geomorphology
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Author : Cooke, C.; Michelutti, N.; Simonetti, A.; Creaser, R.; and Wolfe, A.
Date : 2007.
Title : Spatial and temporal trends of atmospheric metal deposition in the eastern Canadian Arctic.
Publication : 37th Annual International Arctic Workshop. May 2-4, 2007. Skaftafell, Iceland. Institute of Earth Sciences, University of Iceland, Askja, Iceland.
Issue : Program and Abstracts.
Page(s) : 72
Abstract
We measured trace metals and Pb isotopic ratios in a suite of surface sediment samples from lakes extending northward along the east coast of Baffin Island, with the goal of documenting the geographic extent and source of atmospheric metal pollution reaching the eastern Canadian Arctic. In addition, we analyzed a lake-sediment core spanning the last three millennia to gain a temporal perspective on trace-metal and Pb isotopic accumulation histories. Our surface sediment data show an overall trend of decreasing enrichment factors and increasing 206Pb/207Pb ratios with latitude. The lake core data reveal pronounced decreases in 206Pb/207Pb ratios in the most recent sediments, the timing of which corresponds to the introduction of alkyllead additives to gasoline in 1923 (Figure 1). Enrichment factors (relative to pre-industrial sediments) indicate that ~30% of the Pb in the labile fraction in the most recent sediments (deposited between 2001-2005 AD) is from anthropogenic inputs. A two component mixing model indicates that the Pb isotopic composition of the anthropogenic component closely matches the composition of USA Mississippi Valley Type Pb. Coeval increases in enrichment factors for other metals, including As, Co, Cu, Ni, and Zn, provide independent evidence that the natural geochemistry of this remote lake is being altered by anthropogenic pollution. Based on both the spatial and lake core data, we conclude that the most likely source of anthropogenic pollution in this region of the Arctic is from North America. These data are the first to demonstrate that North American industrial emissions can be a dominant source of Pb pollution in the Canadian high Arctic.
Bibliography of Canadian Geomorphology