Mercury Isotope Signatures in Contaminated Sediments as a Tracer for Local Industrial Pollution Sources

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• 作者：Jan G. Wiederhold ; Ulf Skyllberg ; Andreas Drott ; Martin Jiskra ; Sofi Jonsson ; Erik Bj枚rn ; Bernard Bourdon ; Ruben Kretzschmar
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：January 6, 2015
• 年：2015
• 卷：49
• 期：1
• 页码：177-185
• 全文大小：339K
• ISSN：1520-5851

文摘

Mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) may cause characteristic isotope signatures of different mercury (Hg) sources and help understand transformation processes at contaminated sites. Here, we present Hg isotope data of sediments collected near industrial pollution sources in Sweden contaminated with elemental liquid Hg (mainly chlor-alkali industry) or phenyl-Hg (paper industry). The sediments exhibited a wide range of total Hg concentrations from 0.86 to 99 渭g g^鈥?, consisting dominantly of organically-bound Hg and smaller amounts of sulfide-bound Hg. The three phenyl-Hg sites showed very similar Hg isotope signatures (MDF 未²⁰²Hg: 鈭?.2鈥?to 鈭?.5鈥? MIF 螖¹⁹⁹Hg: 鈭?.05鈥?to 鈭?.10鈥?. In contrast, the four sites contaminated with elemental Hg displayed much greater variations (未²⁰²Hg: 鈭?.1鈥?to 0.6鈥? 螖¹⁹⁹Hg: 鈭?.19鈥?to 0.03鈥? but with distinct ranges for the different sites. Sequential extractions revealed that sulfide-bound Hg was in some samples up to 1鈥?heavier in 未²⁰²Hg than organically-bound Hg. The selectivity of the sequential extraction was tested on standard materials prepared with enriched Hg isotopes, which also allowed assessing isotope exchange between different Hg pools. Our results demonstrate that different industrial pollution sources can be distinguished on the basis of Hg isotope signatures, which may additionally record fractionation processes between different Hg pools in the sediments.