Stable Pb isotope ratios in aerosols, precipitation, and size-fractionated particulate matter in the Gulf of Maine, Scotian Shelf, and Labrador Sea

Measurements of Pb isotopes in aerosols, precipitation, and size-fractionated particulate matter from the Gulf of Maine, Scotian Shelf and Labrador Sea are used to investigate the source of Pb. The Pb-206/Pb-207 ratio in aerosols and precipitation collected at New Castle, NH suggests that anthropogenic Pb is a mixture of US and Canadian sources. Pb-206/Pb-207 ratios in >53 mu m particulate matter from the Gulf of Maine and Scotian Shelf slope waters are consistent with contaminant Pb inputs predominantly from US and Canadian sources, while in shelf waters Pb-206/Pb-207 ratios in >0.4 mu m and >53 mu m particles are consistent with a mixture of US and Canadian sources, as well as Pb associated with resuspended surface sediment. Pb-206/Pb-207 ratios in particulate matter (>0.4 mu m, 10-53 mu m, and >53 mu m) from Labrador Sea surface waters range from 1.165 to 1.211 and are a mixture of Pb derived from ore compositions consistent with Broken Hill, Australia and southeast Missouri, US sources. (C) 2010 Elsevier Ltd. All rights reserved.