Microbial Reductive Transformation of Phyllosilicate Fe(III) and U(VI) in Fluvial Subsurface Sediments
Microbial Reductive Transformation of Phyllosilicate Fe(III) and U(VI) in Fluvial Subsurface Sediments
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DOI：
10.1021/es204528m
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发表时间：
2012-04-03
影响因子：
11.4
通讯作者：
Phillips, Jerry L.
中科院分区：
文献类型：
--
作者：
Lee, Ji-Hoon;Fredrickson, James K.;Phillips, Jerry L.
研究了浅层含水层沉积物中Fe（III）和U（VI）的微生物还原;收集自华盛顿州哥伦比亚河汉福德河段附近的地下洪水沉积物。增加0.5 N盐酸可提取的铁（II），观察到在孵育的沉积物和Fe-57穆斯堡尔谱显示，铁（III）与层状硅酸盐和辉石被还原为铁（II）。含水铀（VI）的浓度下降，在地下沉积物中培养含硫酸盐的合成地下水的速率和程度更大的沉积物与有机碳修正。生物还原沉积物的X-射线吸收光谱表明，67 - 77%的U信号是U（VI），可能是一个吸附的物种与一个新的或修改的活性矿物相。系统发育内的Deltaproteobacteria是更常见的汉福德沉积物中孵育U（VI）比没有，在U（VI）-免费的孵育，梭菌目的成员占主导地位的硫酸盐还原菌类型更常见的硫酸盐修正的沉积物。这些结果表明，在汉福德潜水含水层沉积物和生物转化涉及减少和吸附导致水U浓度降低的层状硅酸盐铁（III）和硫酸盐厌氧还原的潜力。
The microbial reduction of Fe(III) and U(VI) was investigated in shallow aquifer sediment; collected from subsurface flood deposits near the Hanford Reach of the Columbia River in Washington State. Increases in 0.5 N HCl-extractable Fe(II) were observed in incubated sediments and Fe-57 Mossbauer spectroscopy revealed that Fe(III) associated with phyllosilicates and pyroxene was reduced to Fe(II). Aqueous uranium(VI) concentrations decreased in subsurface sediments incubated in sulfate-containing synthetic groundwater with the rate and extent being greater in sediment amended with organic carbon. X-ray absorption spectroscopy of bioreduced sediments indicated that 67-77% of the U signal was U(VI), probably as an adsorbed species associated with a new or modified reactive mineral phase. Phylotypes within the Deltaproteobacteria were more common in Hanford sediments incubated with U(VI) than without, and in U(VI)-free incubations, members of the Clostridiales were dominant with sulfate-reducing phylotypes more common in the sulfate-amended sediments. These results demonstrate the potential for anaerobic reduction of phyllosilicate Fe(III) and sulfate in Hanford unconfined aquifer sediments and biotransformations involving reduction and adsorption leading to decreased aqueous U concentrations.