Microbial Populations Associated with the Reduction and Enhanced Mobilization of Arsenic in Mine Tailings
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- 作者：Richard E. Macur ; Jacob T.Wheeler ; Timothy R. McDermott ; and William P. Inskeep
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：September 15, 2001
- 年：2001
- 卷：35
- 期：18
- 页码：3676 - 3682
- 全文大小：125K
- 年卷期：v.35,no.18(September 15, 2001)
- ISSN：1520-5851
文摘
Microbial reduction of arsenate [As(V)] to arsenite[As(III)] and the subsequent effects on As mobilization incontaminated mine tailings were studied under transportconditions. Molecular analysis of bacterial populations andtraditional isolation techniques were used in conjunctionwith column experiments designed to observe relationshipsamong pH (limed vs unlimed treatments), redox potential(Pt electrode), and mobilization of As. Liming increased pHvalues from approximately 4 to 8, resulting in a 5-foldincrease in total As eluted from sterile columns. Elution ofAs from limed columns was further enhanced by microbialactivity. As(III) was the predominant As species eluted fromoxic, nonsterile columns. Conversely, in sterile treatments,As(V) was the predominant valence state in columneffluent. Denaturing gradient gel electrophoresis coupledwith sequence and phylogenetic analysis of 16S rRNA genesegments revealed that liming of the mine tailingsstimulated specific Caulobacter-, Sphingomonas-, andRhizobium-like populations. Pure culture isolates of thesebacteria demonstrated the ability to rapidly reduceAs(V) in aerated serum bottles. An intracellular Asdetoxification pathway was implicated in the reduction of As(V) by these isolates. These results indicate that microbialreduction of As(V) in As-contaminated soils may occurunder aerobic conditions over relatively short time scalesresulting in enhanced As mobilization.