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PT06 Organic, Metallic, Organometallic Pollutants
(PT080) Historical palladium deposition in dated lake sediment cores from remote lakes in Eastern North America and the Arctic.
Yang, F.1, Wang, X.1, Nguyen, N.1, Pienitz, R.2, Vincent, W.3, Smol, J.3, Douglas, M.4, Muir, D.C.G.1, 1 National Water Research Institute, Burlington, ON, Canada2 Département de géographie, Université Laval, Québec, QC, Canada3 Département de biologie, Université Laval, Québec, QC, Canada4 Dept. of Biology, Queens University, Kingston, ON, Canada
ABSTRACT- Use of the platinum group elements (PGEs) particularly platinium (Pt), palladium (Pd), and Rh (Rhodium), in autocatalysts has increased enormously in the past 25 years since the introduction of automobile catalytic converters in 1975. Sediment cores have proven to be particularly useful for tracking inputs of PGEs to the aquatic environment but there have been few studies of remote lakes. In this study dated lake sediment cores were used to examine historical Pd deposition over a 40 degree latitude north-south transect in Canada and USA. The selected lakes, for the most part, were located in remote areas, therefore the input of anthropogenic Pd would be primarily from atmospheric deposition. Pd concentrations in surface slices of each core varied from 0.06 to 0.18 ug/g (dry wt). Pt was at or near detection limits (0.01 ug/g) in these cores. Depth profiles showed that Pd was enriched in recent sediment horizons of mid-latitude lakes but not in Arctic Lakes. Enrichment factors (EFs) for Pd, defined as the ratio of concentration in recent sediments (generally in 1990s to the mean concentration in pre-1900 horizons, were found to be in the range of 0.8 -2.6. Generally higher EFs were found in lakes in southeastern Ontario, southern Quebec and northern New England states. The results suggest Pd is undergoing short range and regional atmospheric transport to these remote water bodies.
Key words: platinum, palladium, sediments, lakes
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