Celo Valbona, Lean David R S, Scott Susannah L
Department of Chemistry, University of Ottawa, Ottawa, ON, Canada.
Sci Total Environ. 2006 Sep 1;368(1):126-37. doi: 10.1016/j.scitotenv.2005.09.043. Epub 2005 Oct 14.
Methylation of inorganic mercury in the aquatic environment has been considered to be largely the result of biological processes, primarily involving sulfate-reducing bacteria. However, these processes cannot account for all of the methylmercury that is formed naturally. A growing body of evidence suggests that chemical reactions represent another possible pathway for mercury methylation in the aquatic environment. In order to assess the abiotic contribution to mercury methylation in the water column, and specifically the conditions under which this contribution may be significant, the current state of knowledge about environmentally significant methylation reactions is reviewed. Results of our laboratory-based investigations of aqueous mercury reactions with some potential methyl donors, including MeCo(dmg)(2)(H2O), a simple model for methylcobalamin, various methyltin compounds and methyl iodide, are presented. In each reaction, the yield of methylmercury and the rate of methylation depend strongly on environmental factors such as pH, temperature, and the presence of complexing agents, especially chloride.
水生环境中无机汞的甲基化在很大程度上被认为是生物过程的结果，主要涉及硫酸盐还原菌。然而，这些过程并不能解释所有自然形成的甲基汞。越来越多的证据表明，化学反应是水生环境中汞甲基化的另一种可能途径。为了评估水柱中汞甲基化的非生物贡献，特别是这种贡献可能显著的条件，本文综述了有关具有环境意义的甲基化反应的现有知识。本文还介绍了我们基于实验室的关于汞与一些潜在甲基供体（包括甲基钴胺素的简单模型MeCo(dmg)(2)(H2O)、各种甲基锡化合物和甲基碘）的水相反应的研究结果。在每个反应中，甲基汞的产率和甲基化速率在很大程度上取决于环境因素，如pH值、温度以及络合剂（尤其是氯化物）的存在。
