摘要:
汞是环境中存在的一种重要污染物质,其毒性与之化学形态密切相关。环境中的汞主要以无机汞形态存在,然而无机汞可以通过甲基化作用转化为毒性更强的甲基汞,从而给受到暴露的生物及人类带来更高的健康风险。沉积物是汞在水生环境系统中的主要分布相,也是无机汞甲基化过程发生的主要场所。沉积物中汞的甲基化过程受到生物种类、汞的生物可利用性等生物因素及温度、含硫化合物、有机质、氧化还原条件等环境理化性质的影响。本文对汞在沉积物中甲基化过程的作用机制及其影响因素的研究现状及最新进展进行了总结,并对未来更深入的研究进行了展望。
关键词:
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汞
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沉积物
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甲基化
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生物可利用性
Abstract:
Mercury is an important contaminant existed in the environment, and the toxicity of mercury strongly depends on its chemical species. Mercury exists in the natural environment mainly as inorganic mercury, however, inorganic mercury could be transformed to methylmercury (a more toxic form) via methylation process, thus pose higher health risk to the exposed biota and human beings. Sediments are often considered as the major sink of mercury in aquatic environment, and it is also the major site where mercury methylation occurs. Mercury methylation processes in sediments are controlled by various biotic (e. g., biological species and Hg bioavailability) and abiotic factors (e. g., temperature, sulfur compound, organic matter and redox conditions). The present article summarizes the research history and recent progresses in studying the mechanisms underlying mercury methylation in sediments and its influencing factors, and further draw some perspectives for future research.
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