Coupling of arsenic mobility to sulfur transformations during microbial sulfate reduction in the presence and absence of humic acid
Coupling of arsenic mobility to sulfur transformations during microbial sulfate reduction in the presence and absence of humic acid
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DOI：
10.1016/j.chemgeo.2013.02.005
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发表时间：
2013-04-08
期刊：
影响因子：
3.9
通讯作者：
Planer-Friedrich, Britta
中科院分区：
文献类型：
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作者：
Burton, Edward D.;Johnston, Scott G.;Planer-Friedrich, Britta
在砷污染的地下环境中，微生物硫酸盐还原是一个重要的末端电子接受过程。腐植酸在这样的环境中普遍存在，但人们对它们在硫酸盐还原条件下对砷移动性的影响知之甚少。在这项研究中，我们通过一系列的平流柱实验考察了微生物硫酸盐还原和腐植酸对砷的活化作用。这些实验中的初始固相由石英砂组成，石英砂上覆盖有吸附了As(III)的针铁矿(α-FeOOH)。通过比较不含腐植酸和存在腐植酸的人工地下水柱对腐植酸的影响来评价腐植酸的影响，同时通过比较接种硫酸盐还原细菌普通脱硫弧菌(ATCC菌株7757)的柱和非生物对照柱来考察微生物硫酸盐还原的效果。无论是非生物柱还是接种柱(硫酸盐还原)，高浓度腐植酸的存在本身并不能提高砷的总体释放程度。这与过滤至两者的孔隙水中的砷浓度相似。
Microbial sulfate reduction is an important terminal electron accepting process in arsenic-contaminated subsurface environments. Humic acids are ubiquitous in such environments, yet their impact on arsenic mobility under sulfate-reducing conditions is poorly understood. In this study, we examined the effects of microbial sulfate reduction and humic acid on arsenic mobilization via a series of advective-flow column experiments. The initial solid-phase in these experiments comprised quartz sand that was coated with As(III)-sorbed goethite (alpha-FeOOH). The effect of humic acid was assessed by comparing columns that received artificial groundwater in which humic acid was either absent or present at 100 mg L-1, whilst the effect of microbial sulfate reduction was investigated by comparing columns that were inoculated with the sulfate-reducer Desulfovibrio vulgaris (ATCC strain 7757) versus abiotic control columns. The presence of high concentrations of humic acid alone did not enhance the overall extent of arsenic release from either the abiotic or the inoculated (sulfate reducing) columns. This is consistent with similar arsenic concentrations in porewaters filtered to both