| Equilibrium mercury isotope fractionation between dissolved Hg(II) species and thiol-bound Hg. | |
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MedLine Citation:
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PMID: 20443581 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Stable Hg isotope ratios provide a new tool to trace environmental Hg cycling. Thiols (-SH) are the dominant Hg-binding groups in natural organic matter. Here, we report experimental and computational results on equilibrium Hg isotope fractionation between dissolved Hg(II) species and thiol-bound Hg. Hg(II) chloride and nitrate solutions were equilibrated in parallel batches with varying amounts of thiol resin resulting in different fractions of thiol-bound and free Hg. Mercury isotope ratios in both fractions were analyzed by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). Theoretical equilibrium Hg isotope effects by mass-dependent fractionation (MDF) and nuclear volume fractionation (NVF) were calculated for 14 relevant Hg(II) species. The experimental data revealed that thiol-bound Hg was enriched in light Hg isotopes by 0.53 per thousand and 0.62 per thousand (delta(202)Hg) relative to HgCl(2) and Hg(OH)(2), respectively. The computational results were in excellent agreement with the experimental data indicating that a combination of MDF and NVF was responsible for the observed Hg isotope fractionation. Small mass-independent fractionation (MIF) effects (<0.1 per thousand) were observed representing one of the first experimental evidences for MIF of Hg isotopes by NVF. Our results indicate that significant equilibrium Hg isotope fractionation can occur without redox transition, and that NVF must be considered in addition to MDF to explain Hg isotope variations. |
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Authors:
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Jan G Wiederhold; Christopher J Cramer; Kelly Daniel; Ivan Infante; Bernard Bourdon; Ruben Kretzschmar |
Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Environmental science & technology Volume: 44 ISSN: 0013-936X ISO Abbreviation: Environ. Sci. Technol. Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-05-27 Completed Date: 2010-07-19 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0213155 Medline TA: Environ Sci Technol Country: United States |
Other Details:
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Languages: eng Pagination: 4191-7 Citation Subset: IM |
Affiliation:
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Institute of Biogeochemistry and Pollutant Dynamics, Soil Chemistry, and Institute of Geochemistry and Petrology, Isotope Geochemistry, ETH Zurich, Switzerland. wiederhold@env.ethz.ch |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Isotopes
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chemistry* Mercury / chemistry* Solubility Sulfhydryl Compounds / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Isotopes; 0/Sulfhydryl Compounds; 7439-97-6/Mercury |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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