CGRG Bibliography of Canadian Geomorphology
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Author : Forsythe, K.W.; and Dekryger, J.
Date : 2008.
Title : Analysis of metal and organic contaminants in Lake Ontario sediments: 1968 to 1998.
Publication : 2008 Annual Meetings of the Canadian Association of Geographers, Ontario Division and the American Association of Geographers, East Lakes Division. October 17-19, 2008. Brock University. St. Catharines, Ontario.
Issue :
Page(s) :
Abstract
This research utilized surficial sediment core sample data collected under the Environment Canada Great Lakes Sediment Assessment Program. The first survey for Lake Ontario was conducted in 1968; followed by a second in 1998. Contaminants were measured at 278 and 70 sampling locations respectively. Eight metals (arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc) and two organic pollutants (Dieldrin, PP'DDE) were directly comparable between years. The ordinary kriging spatial interpolation technique as implemented in the ArcGIS software was employed to create individual prediction maps based on the sample values. One of the adva ntages of utilizing this technique is that statistical validation of the prediction surfaces is possible. The results show improvements in some contaminant concentrations over time; however large areas within the lake still exceed sediment quality guidelines in terms of the Threshold Effect Level (TEL) and the Probable Effect Level (PEL) as defined by the Canadian Council of Ministers of the Environment. Higher pollutant concentrations were generally found in depositional basins and were also associated with annualized lake circulation patterns. Contaminated sediments are an important factor to consider when examining the health of lake ecosystems. The interpolated kriging surfaces are more informative than i.e., conventional dot and/or proportional circle maps in the amount of information they present. They also provide an increased understanding of both the spatial distribution and temporal trends in sediment contamination for Lake Ontario.
Bibliography of Canadian Geomorphology