The role of indigenous bacteria in mobilization of sediment bound arsenic (As) into groundwater is investigated using subsurface sediment from Brahmaputra River Basin (BRB) and the Bacillus sp. strain IIIJ3-1, an indigenous species to BRB. Anaerobic sediment microcosms with varying organic carbon sources and terminal electron acceptors (TEAs) are used to illustrate the role of the test bacterium in As mobilization. The aquifer sediment shows an asymmetric distribution of As and Fe in its different phases. Among the TEAs added, NO3 amendment promotes higher cell growth, oxalic acid production and maximum release of sediment bound As. X-ray diffraction analysis further suggests that weathering of As bearing secondary minerals through bacterial action enhances As bioavailability, followed by dissimilatory reduction and thus promotes its mobilization into aqueous phase. Co-release pattern of other elements from the sediment indicates that release of As is decoupled from that of Fe. This study confirms that microbe-mediated mineral weathering followed by respiratory reduction of As facilitates mobilization of sediment hosted As into aqueous phase, and provides a better insight into the catabolic ability of groundwater bacteria in mobilization of sediment hosted As in BRB region.

中文翻译：

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基于微观世界的芽孢杆菌砷释放潜力分析。不同氧化还原条件下的菌株 IIIJ3-1

使用来自雅鲁藏布江盆地 (BRB) 和芽孢杆菌的地下沉积物研究了土著细菌在将沉积物结合的砷 (As) 迁移到地下水中的作用。菌株 IIIJ3-1，BRB 的本地物种。具有不同有机碳源和末端电子受体 (TEA) 的厌氧沉积物微观世界被用来说明测试细菌在 As 动员中的作用。含水层沉积物显示出不同相中 As 和 Fe 的不对称分布。在添加的 TEA 中，NO3 修正促进了更高的细胞生长、草酸的产生和沉积物结合 As 的最大释放。X 射线衍射分析进一步表明，通过细菌作用使含砷的次生矿物风化提高了砷的生物利用度，然后是异化还原，从而促进其迁移到水相中。沉积物中其他元素的共释放模式表明 As 的释放与 Fe 的释放脱钩。该研究证实，微生物介导的矿物风化以及 As 的呼吸还原有助于将 As 沉积物移动到水相中，并提供对地下水细菌在 BRB 区域沉积物沉积物移动中的分解代谢能力的更好见解。