Transformation of arsenic in offshore sediment under the impact of anaerobic microbial activities.
Transformation of arsenic in offshore sediment under the impact of anaerobic microbial activities.
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DOI：
10.1016/j.watres.2011.10.041
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发表时间：
2011-12
期刊：
影响因子：
12.8
通讯作者：
Liying Xu;Zhixi Zhao;Shaofeng Wang;R. Pan;Yongfeng Jia
中科院分区：
文献类型：
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作者：
Liying Xu;Zhixi Zhao;Shaofeng Wang;R. Pan;Yongfeng Jia
沉积物中的砷在迁移和埋藏过程中通常会发生相变。本工作研究了近海沉积物中厌氧微生物介导的砷形态变化，并监测了羟基氧化物缔合砷酸盐向硫化物缔合形式的转化过程。砷的命运和可能的转化途径进行了讨论的基础上定量分析的水和固体砷和铁，定性表征，使用X射线吸收近边光谱（XANES）。砷的释放和减少后，缺氧条件的发展，但后来被requestered的自生矿物。沉积物中的大部分砷被转化为类砷物质。硫化物在砷的再分配过程中可能起着双重作用，即早期促进砷从宿主羟基氧化物中释放，后期以硫化砷的形式将砷从溶液中去除。研究结果表明，砷转化的途径时，砷酸盐的运输和埋藏在近海沉积物的氧化还原边界以下。
Sediment bound arsenic usually undergoes phase transformation processes when it is transported and buried in deeper settings. This work investigated anaerobic microbial mediated speciation change of the arsenic in offshore sediment and monitored the transformation process of oxyhydroxide associated arsenate to sulfide associated forms. The fate of arsenic and possible pathways of transformation were discussed based on quantitative analysis of aqueous and solid arsenic and iron, and qualitative characterization using X-ray absorption near edge spectroscopy (XANES). Arsenic was released and reduced upon development of anoxic conditions but was resequestered by authigenic minerals later. Most of the arsenic in the sediment was converted to orpiment-like material. Sulfide may have played double roles in arsenic redistribution process, i.e. promoting arsenic release from host oxyhydroxides in early stage and removal of arsenite from solution in the form of arsenic sulfide in later stage. The findings have implications about the pathways of arsenic transformation when arsenate is transported and buried below redox boundaries in offshore sediment.