Department of Land, Air, and Water Resources, University of California, Davis, Davis, CA 95616, USA.
Sci Total Environ. 2011 Jan 1;409(3):631-7. doi: 10.1016/j.scitotenv.2010.10.030. Epub 2010 Nov 13.
The presence of inorganic mercury (IHg) and methylmercury (MeHg) in surface waters is a health concern worldwide. This study assessed the removal potential use of metal-based coagulants as a means to remove both dissolved IHg and MeHg from natural waters and provides information regarding the importance of Hg associations with the dissolved organic matter (DOM) fraction and metal hydroxides. Previous research indicated coagulants were not effective at removing Hg from solution; however these studies used high concentrations of Hg and did not reflect naturally occurring concentrations of Hg. In this study, water collected from an agricultural drain in the Sacramento-San Joaquin Delta was filtered to isolate the dissolved organic matter (DOM) fraction. The DOM was then treated with a range of coagulant doses to determine the efficacy of removing all forms of Hg from solution. Three industrial-grade coagulants were tested: ferric chloride, ferric sulfate, and polyaluminum chloride. Coagulation removed up to 85% of DOM from solution. In the absence of DOM, all three coagulants released IHg into solution, however in the presence of DOM the coagulants removed up to 97% of IHg and 80% of MeHg. Results suggest that the removal of Hg is mediated by DOM-coagulant interactions. There was a preferential association of IHg with the more aromatic, higher molecular weight fraction of DOM but no such relationship was found for MeHg. This study offers new fundamental insights regarding large-scale removal of Hg at environmentally relevant regarding large-scale removal of Hg at environmentally relevant concentrations.
无机汞（IHg）和甲基汞（MeHg）在地表水中的存在是一个全球性的健康关注点。本研究评估了使用基于金属的混凝剂去除天然水中溶解的 IHg 和 MeHg 的去除潜力，并提供了有关 Hg 与溶解有机物（DOM）部分和金属氢氧化物结合的重要性的信息。先前的研究表明，混凝剂不能有效地从溶液中去除 Hg；然而，这些研究使用了高浓度的 Hg，并没有反映出自然存在的 Hg 浓度。在这项研究中，从萨克拉门托-圣华金三角洲的农业排水中采集的水被过滤以分离溶解的有机物（DOM）部分。然后用一系列混凝剂剂量处理 DOM，以确定从溶液中去除所有形式 Hg 的效果。测试了三种工业级混凝剂：三氯化铁、硫酸铁和聚合氯化铝。混凝剂可去除高达 85%的溶解有机物（DOM）。在不存在 DOM 的情况下，三种混凝剂都会将 IHg 释放到溶液中，但在存在 DOM 的情况下，混凝剂可去除高达 97%的 IHg 和 80%的 MeHg。结果表明，Hg 的去除是由 DOM-混凝剂相互作用介导的。IHg 优先与 DOM 的更具芳香性、更高分子量部分结合，但对于 MeHg 则没有这种关系。这项研究提供了有关在环境相关浓度下大规模去除 Hg 的新的基本见解。
