image: Pictured is the rosette system for trace metal-clean sampling of seawater with Canadian Geotraces team members during one of the 2015 Arctic cruises. view more
Credit: Kathryn Purdon (University of Victoria, Victoria, Canada).
A study reports lead pollution in the remote western Arctic Ocean. Anthropogenic lead contamination is widespread in the natural environment. However, anthropogenic sources are thought to be negligible contributors to lead in Canadian Arctic seawater. Bridget A. Bergquist and colleagues isolated dissolved lead from seawater samples collected on Canadian Arctic cruises, which were part of an international program to study marine cycling of trace elements, at depths ranging from the surface to 3,500 meters, and measured lead isotopes to determine their provenance. The results revealed that an average of 60% of lead throughout the water column of the Canada Basin came from anthropogenic sources. Based on the isotope analysis, a major source of the anthropogenic lead in seawater was historic lead from Europe and Russia deposited in the Arctic region during the peak of lead emissions in the 20th century. The 20th-century Eurasian lead signature was strongest in the top 1,000 meters over and closest to the continental shelf, suggesting that historic lead pollutants are being remobilized and released into seawater from resuspension of shelf materials and coastal erosion. Thus, the acceleration of melting permafrost and ice and increasing coastal erosion are likely to result in continued remobilization of historic contaminants, and lead isotopes can be a sensitive tracer of contaminants in Arctic seawater, according to the authors.
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Article #2021-00023: "Anthropogenic lead pervasive in Canadian Arctic seawater," by Joan De Vera et al.
MEDIA CONTACT: Bridget A. Bergquist, University of Toronto, CANADA; tel: 647-988-7638; email: <bergquist@es.utoronto.ca>
Journal
Proceedings of the National Academy of Sciences