Differential Arsenic Mobilization from As-Bearing Ferrihydrite by Iron-Respiring Shewanella Strains with Different Arsenic-Reducing Activities

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• 作者：Shenghua Jiang ; Ji-Hoon Lee ; Donghun Kim ; Robert A. Kanaly ; Min-Gyu Kim ; Hor-Gil Hur
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：August 6, 2013
• 年：2013
• 卷：47
• 期：15
• 页码：8616-8623
• 全文大小：441K
• 年卷期：v.47,no.15(August 6, 2013)
• ISSN：1520-5851

文摘

Arsenic immobilization and release in the environment is significantly influenced by bacterial oxidation and reduction of arsenic and arsenic-bearing minerals. In this study, we tested three iron-reducing bacteria, Shewanella oneidensis MR-1, Shewanella sp. HN-41, and Shewanella putrefaciens 200, which have diverse arsenate-reducing activities with regard to reduction of an As-bearing ferrihydrite slurry. In the cultures of S. oneidensis MR-1 and Shewanella sp. HN-41, which are not capable of respiratory reduction of As(V) to As(III), arsenic was maintained predominantly in its pentavalent form, existing in particulate poorly crystalline As-bearing ferrihydrite and formed small quantities of a stable ferrous arsenate [Fe₃(AsO₄)₂] precipitate. However, in the culture of the As(V) reducer, S. putrefaciens 200, As(V) was reduced to As(III) and a small fraction of As-bearing ferrihydrite was transformed into ribbon-shaped siderite that subsequently re-released arsenic into the liquid phase. Our results indicated that release of arsenic and formation of diverse secondary nanoscale Fe鈥揂s minerals are specifically closely related to the arsenic-reducing abilities of different bacteria. Therefore, bacterial arsenic reduction appears to significantly influence As mobilization in soils, minerals, and other Fe-rich environments.