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首页> 外文期刊>Environmental Science & Technology >Mercury Isotope Fractionation during Aqueous Photoreduction of Monomethylmercury in the Presence of Dissolved Organic Matter
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Mercury Isotope Fractionation during Aqueous Photoreduction of Monomethylmercury in the Presence of Dissolved Organic Matter

机译：溶解有机物存在下单甲基汞光还原过程中的汞同位素分馏

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摘要

Monomethylmercury (MMHg) is a toxic pollutant that bioaccumulates in aquatic food webs. A major mechanism that limits MMHg uptake by biota is photodemethylation in surface waters. Recently, the extent of mass-independent fractionation (MIF) of Hg isotopes preserved in fish is being used to quantify this MMHg sink. Here, the effects of different types and amounts of DOM on Hg MIF during MMHg photodemethylation were investigated to assess how variable MIF enrichment factors may be with respect to changing DOM binding sites. From experiments conducted with varying amounts of reduced organic sulfur (S_(red)-DOM), the extent and signature of MIF is likely dependent on whether MMHg is dominantly bound to S_(red)- DOM. Similar enrichment factors were observed for low MMHg:S_(red)- DOM experiments, where S_(red)-DOM was in far excess of MMHg. In contrast, significantly lower and variable enrichment factors were observed for experiments with higher MMHg:S_(red)-DOM ratios. Additionally the relationship between the two odd Hg isotopes that display MIF (△~(199)Hg/△~(201)Hg) was consistent for the low MMHg:S_(red)-DOM experiments, while lower △~(199)Hg/ △~(201)Hg relationships were observed for the higher MMHg:S_(red)-DOM experiments. These results suggest that both the extent and signature of MMHg MIF are sensitive to different ligands that bind MMHg in nature.
机译：单甲基汞（MMHg）是一种有毒污染物，会在水生食物网中生物累积。限制生物群吸收MMHg的主要机制是地表水中的光脱甲基化。最近，鱼类中保存的Hg同位素的质量独立分级分离（MIF）的程度已用于量化此MMHg汇。在这里，研究了MMHg光脱甲基化过程中不同类型和数量的DOM对Hg MIF的影响，以评估可变的MIF富集因子相对于DOM结合位点的变化可能如何。从使用不同数量的还原有机硫（S_（red）-DOM）进行的实验中，MIF的程度和特征可能取决于MMHg是否主要与S_（red）-DOM结合。在低MMHg：S_（red）-DOM实验中观察到相似的富集因子，其中S_（red）-DOM远远超过MMHg。相反，对于具有较高MMHg：S_（red）-DOM比的实验，观察到明显较低且富集的可变因子。另外，在低MMHg：S_（red）-DOM实验中，显示MIF的两个奇数Hg同位素（△〜（199）Hg /△〜（201）Hg）之间的关系一致，而△〜（199）Hg较低在较高的MMHg：S_（red）-DOM实验中观察到/△〜（201）Hg关系。这些结果表明，MMHg MIF的范围和特征都对自然界中结合MMHg的不同配体敏感。

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  • 来源
    《Environmental Science & Technology》 |2015年第1期|259-267|共9页
  • 作者

    Priyanka Chandan; Sanghamitra Ghosh; Bridget A. Bergquist;

  • 作者单位

    University of Toronto, Department of Earth Sciences, 22 Russell Street, Toronto, Ontario M5S 3B1, Canada;

    Indian Institute of Technology, School of Earth, Ocean and Climate Sciences, Bhubaneswar, Odisha 751 007, India;

    University of Toronto, Department of Earth Sciences, 22 Russell Street, Toronto, Ontario M5S 3B1, Canada;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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