Microbial mobilization of arsenic from sediments of the Aberjona Watershed
Microbial mobilization of arsenic from sediments of the Aberjona Watershed
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DOI：
10.1021/es970124k
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发表时间：
1997-10-01
影响因子：
11.4
通讯作者：
Morel, FMM
中科院分区：
文献类型：
--
作者：
Ahmann, D;Krumholz, LR;Morel, FMM
水生沉积物中的砷迁移是一个令人关切的问题，因为水载砷可以迁移到原始地区，危及水生生物和人类。这种动员在阿伯乔纳流域分布在整个河流和湖泊沉积物中的砷近20吨。为了了解可能的生物机制，有助于这种运输，动员固相砷进行了调查，在上阿伯乔纳沉积物微观世界。微宇宙催化砷从砷酸铁中快速溶解，砷酸铁是沉积砷的固相替代物，动员了20-28%的砷。消毒阻止了这种转变。砷酸盐还原为亚砷酸盐的过程伴随着砷酸铁的溶解，表明还原是溶解的驱动力。沉淀条件，过滤灭菌培养基显示没有砷转化活性。硫酸盐还原菌的天然富集培养物具有五分之一的微观世界活性，而菌株MIT-13，一种天然的砷酸盐还原微生物，表现出更大的活性，溶解了38%的砷。此外，菌株MIT-13动员砷预消毒，未经修正的上阿伯乔纳沉积物。这些结果表明，微生物对沉积物中的砷具有直接的动员作用，表明MIT-13菌株是一种强的砷转化菌，并表明异化砷还原作用可能有助于Aberjona流域砷污染最严重地区缺氧沉积物中砷的通量。
Arsenic mobilization from aquatic sediments is an issue of concern, as water-borne arsenic can migrate into pristine areas, endangering aquatic organisms and people. Such mobilization in the Aberjona Watershed has distributed nearly 20 t of arsenic throughout river and lake sediments. To gain an understanding of possible biological mechanisms contributing to this transport, mobilization of solid-phase arsenic was investigated in upper Aberjona sediment microcosms. Microcosms catalyzed rapid dissolution of arsenic from iron arsenate, a solid-phase surrogate for sedimentary arsenic, mobilizing 20-28% of the arsenic present. Sterilization prevented this transformation. Reduction of arsenate to arsenite accompanied iron arsenate dissolution, suggesting that reduction was driving dissolution. Sediment-conditioned, filter-sterilized medium showed no arsenic-transforming activity. A native enrichment culture of sulfate-reducing bacteria possessed one-fifth of the microcosm activity, while strain MIT-13, a native arsenate-reducing microorganism, showed much greater activity, dissolving 38% of the arsenic present. Furthermore, strain MIT-13 mobilized arsenic from presterilized, unamended upper Aberjona sediments. These observations indicate that a direct microbial arsenic-mobilizing activity exists in the sediments, show that strain MIT-13 is a strong arsenic-transforming a gent native to the sediments, a nd suggest th at dissimilatory arsenic reduction may contribute to arsenic flux from anoxic sediments in the most arsenic-contaminated region of the Aberjona Watershed.