Speciation change and redistribution of arsenic in soil under anaerobic microbial activities.
Speciation change and redistribution of arsenic in soil under anaerobic microbial activities.
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DOI：
10.1016/j.jhazmat.2015.09.030
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发表时间：
2016-01
影响因子：
13.6
通讯作者：
Liying Xu;Xi Wu;Shaofeng Wang;Zidan Yuan;F. Xiao;Ming Yang;Yongfeng Jia
中科院分区：
文献类型：
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作者：
Liying Xu;Xi Wu;Shaofeng Wang;Zidan Yuan;F. Xiao;Ming Yang;Yongfeng Jia
土壤中砷的形态和行为受到氧化还原条件的强烈影响。本文研究了厌氧条件下砷在土壤中的形态转化和再分布。通过向培养体系中添加硫酸盐，考察了微生物硫化作用对这些过程的影响。在厌氧培养过程中，As(III)是溶液中的主要砷形态。溶解砷浓度随培养时间的变化曲线呈“M”型，如添加硫酸盐的体系在24小时和240小时左右出现两个峰值。在孵化初期，砷被释放并还原为As(III)，然后再进入固相。在产生过量硫化物后，再提取的砷通过形成硫代亚砷酸盐再次释放(可能是由于溶解的硫化物离子溶解了AsS)。在孵化过程结束时，大部分溶解的砷被再次从溶液中去除。这些发现可能对被淹的富硫土壤中砷的命运有重要的影响。
Arsenic speciation and behavior in soil are strongly affected by redox conditions. This work investigated speciation transformation and redistribution of arsenic in soil under anaerobic conditions. The effect of microbial sulfidogenesis on these processes was examined by addition of sulfate to the incubation systems. As(III) was found to be the dominant arsenic species in solution during the process of anaerobic incubation. The change of dissolved As concentration with incubation time showed “M” shaped profiles, e.g. the curves displaying two peaks at approximately 24 h and 240 h for the system with added sulfate. Arsenic was released and reduced to As(III) in the early stage of the incubation, and then resequestered into the solid phase. After excess sulfide was generated, the resequestered arsenic was released again (probably due to the dissolution of arsenic sulfide by dissolved sulfide ions) via the formation of thioarsenite. At the end of the incubation process, most of the dissolved arsenic was removed again from solution. The findings may have important implications to the fate of arsenic in flooded sulfur-rich soils.