Reductive Dissolution of Tl(I)鈥揓arosite by Shewanella putrefaciens: Providing New Insights into Tl Biogeochemistry

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• 作者：Christina M. Smeaton ; Gillian E. Walshe ; Brian J. Fryer ; Christopher G. Weisener
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：October 16, 2012
• 年：2012
• 卷：46
• 期：20
• 页码：11086-11094
• 全文大小：448K
• 年卷期：v.46,no.20(October 16, 2012)
• ISSN：1520-5851

文摘

Thallium (Tl) is emerging as a metal of concern in countries such as China due to its release during the natural weathering of Tl-bearing ore deposits and mining activities. Despite the high toxicity of Tl, few studies have examined the reductive dissolution of Tl mineral phases by microbial populations. In this study we examined the dissolution of synthetic Tl(I)鈥搄arosite, (H₃O)_0.29Tl_0.71Fe_2.74(SO₄)₂(OH)_5.22(H₂O)_0.78, by Shewanella putrefaciens CN32 using batch experiments under anaerobic circumneutral conditions. Fe(II) concentrations were measured over time and showed Fe(II) production (4.6 mM) in inoculated samples by 893 h not seen in mineral and dead cell controls. Release of aqueous Tl was enhanced in inoculated samples whereby maximum concentrations in inoculated and cell-free samples reached 3.2 and 2.1 mM, respectively, by termination of the experiment. Complementary batch Tl/S. putrefaciens sorption experiments were conducted under experimentally relevant pH (5 and 6.3) at a Tl concentration of 35 渭M and did not show significant Tl accumulation by either live or dead cells. Therefore, in contrast to many metals such as Pb and Cd, S. putrefaciens does not represent a sink for Tl in the environment and Tl is readily released from Tl鈥搄arosite during both abiotic and biotic dissolution.