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首页> 外文期刊>Environmental Science & Technology >Role of Settling Particles on Mercury Methylation in the Oxic Water Column of Freshwater Systems
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Role of Settling Particles on Mercury Methylation in the Oxic Water Column of Freshwater Systems

机译：沉淀颗粒对淡水系统含氧水塔中汞甲基化的作用

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摘要

As the methylation of inorganic mercury to neurotoxic methylmercury has been attributed to the activity of anaerobic bacteria, the formation of methylmercury in the oxic water column of marine ecosystems has puzzled scientists over the past years. Here we show for the first time that methylmercury can be produced in particles sinking through oxygenated water column of lakes. Total mercury and methylmercury concentrations were measured in the settling particles and in surface sediments of the largest freshwater lake in Western Europe (Lake Geneva). While total mercury concentration differences between sediments and settling particles were not significant, methylmercury concentrations were about ten-fold greater in settling particles. Methylmercury demethylation rate constants (k_d) were of similar magnitude in both compartments. In contrast, mercury methylation rate constants (k_m) were one order of magnitude greater in settling particles. The net potential for methylmercury formation, assessed by the ratio between the two rate constants (k_m k_d~(-1)), was therefore up to ten fold greater in settling particles, denoting that in situ transformations likely contributed to the high methylmercury concentration found in settling particles. Mercury methylation was inhibited (～80%) in settling particles amended with molybdate, demonstrating the prominent role of biological sulfate-reduction in the process.
机译：由于无机汞甲基化为神经毒性甲基汞的原因是厌氧细菌的活性，因此，过去几年中海洋生态系统含氧水柱中甲基汞的形成使科学家感到困惑。在这里，我们首次表明，通过湖泊氧化水柱沉没的颗粒中会产生甲基汞。测量了西欧最大的淡水湖（日内瓦湖）的沉降颗粒和表面沉积物中的总汞和甲基汞浓度。尽管沉积物和沉降颗粒之间的总汞浓度差异不明显，但沉降颗粒中的甲基汞浓度大约高十倍。在两个隔室中，甲基汞的脱甲基速率常数（k_d）大小相似。相反，在沉降颗粒中，汞甲基化速率常数（k_m）大一个数量级。因此，通过两个速率常数（k_m k_d〜（-1）之间的比率）评估，甲基汞形成的净潜能高出沉降颗粒的十倍之多，这表明原位转化可能有助于发现高浓度的甲基汞。在沉降颗粒中。在用钼酸盐修正的沉降颗粒中，汞的甲基化被抑制（〜80％），这表明在该过程中生物硫酸盐还原的重要作用。

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  • 来源
    《Environmental Science & Technology》 |2016年第21期|11672-11679|共8页
  • 作者

    Elena Gascon Diez; Jean-Luc Loizeau; Claudia Cosio; Sylvain Boucher; Thierry Adatte; David Amouroux; Andrea G. Bravo;

  • 作者单位

    Department F.-A. Forel for Environmental and Water Sciences, University of Geneva, Boulevard Carl-Vogt 66, 1211 Geneva 4, Switzerland;

    Department F.-A. Forel for Environmental and Water Sciences, University of Geneva, Boulevard Carl-Vogt 66, 1211 Geneva 4, Switzerland;

    Department F.-A. Forel for Environmental and Water Sciences, University of Geneva, Boulevard Carl-Vogt 66, 1211 Geneva 4, Switzerland;

    Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-Chimie pour I'Environnement et Ies Materiaux, UMR 5254 CNRS, Universite de Pau et des Pays de l'Adour, Helioparc, 64053 Pau, France;

    Institute of Earth Sciences (ISTE), University of Lausanne, 1015 Lausanne, Switzerland;

    Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-Chimie pour I'Environnement et Ies Materiaux, UMR 5254 CNRS, Universite de Pau et des Pays de l'Adour, Helioparc, 64053 Pau, France;

    Limnology Department, Evolutionary Biology Centre, EBC, Norbyvagen 18D, 75236 Uppsala, Sweden;

  • 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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