Microbial Reductive Transformation of Phyllosilicate Fe(III) and U(VI) in Fluvial Subsurface Sediments

作者：Lee Ji Hoon; Fredrickson James K^*; Kukkadapu Ravi K; Boyanov Maxim I; Kemner Kenneth M; Lin Xueju; Kennedy David W; Bjornstad Bruce N; Konopka Allan E; Moore Dean A; Resch Charles T; Phillips Jerry L

来源：Environmental Science & Technology, 2012, 46(7): 3721-3730.

DOI：10.1021/es204528m

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.

• 出版日期2012-4-3