Pyrogenic Inputs of Anthropogenic Pb and Hg to Sediments of the Hood Canal, Washington, in the 20th Century: Source Evidence from Stable Pb Isotopes and PAH Signatures

详细信息    查看全文

• 作者：Patrick Louchouarn ; Li-Jung Kuo ; Jill M. Brandenberger ; Franco Marcantonio ; Charity Garland ; Gary A. Gill ; Valerie Cullinan
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：June 5, 2012
• 年：2012
• 卷：46
• 期：11
• 页码：5772-5781
• 全文大小：415K
• 年卷期：v.46,no.11(June 5, 2012)
• ISSN：1520-5851

文摘

Combustion-derived PAHs and stable Pb isotopic signatures (²⁰⁶Pb/²⁰⁷Pb) in sedimentary records assisted in reconstructing the sources of atmospheric inputs of anthropogenic Pb and Hg to the Hood Canal, Washington. The sediment-focusing corrected peak fluxes of total Pb and Hg (1960鈥?0s) demonstrate that the watershed of Hood Canal has received greater atmospheric inputs of these metals than its mostly rural land use would predict. The tight relationships between the Pb, Hg, and organic markers in the cores indicate that these metals are derived from industrial combustion emissions. Multiple lines of evidence point to the Asarco smelter, located in the Main Basin of Puget Sound, as the major emission source of these metals to the watershed of the Hood Canal. The evidence includes (1) similar PAH isomer ratios in sediment cores from the two basins, (2) the correlations between Pb, Hg, and Cu in sediments and previously studied environmental samples including particulate matter emitted from the Asarco smelter鈥檚 main stack at the peak of production, and (3) Pb isotope ratios. The natural rate of recovery in Hood Canal since the 1970s, back to preindustrial metal concentrations, was linear and contrasts with recovery rates reported for the Main Basin which slowed post late 1980s.