Smeaton Christina M, Fryer Brian J, Weisener Christopher G
Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada, N9B 3P4.
Environ Sci Technol. 2009 Nov 1;43(21):8086-91. doi: 10.1021/es901629c.
Jarosites (MFe(3)(SO(4))(2)(OH)(6)) are precipitated in the Zn industry to remove impurities during the extraction process and contain metals such as Pb and Ag. Jarosite wastes are often confined to capped tailings ponds, thereby creating potential for anaerobic reductive dissolution by microbial populations. This study demonstrates the reductive dissolution of synthetic Pb-jarosite (PbFe(6)(SO(4))(4)(OH)(12)) by a subsurface dissimilatory Fe reducing bacterium (Shewanella putrefaciens CN32) using batch experiments under anaerobic circumneutral conditions. Solution chemistry, pH, Eh, and cell viability were monitored over time and illustrated the reduction of released structural Fe(III) from the Pb-jarosite to Fe(II). Inoculated samples containing Pb-jarosite also demonstrated decreased cellular viability coinciding with increased Pb concentrations. SEM images showed progressive nucleation of electron dense nanoparticles on the surface of bacteria, identified by TEM/EDS as intracellular crystalline precipitates enriched in Pb and P. The intracellular precipitation of Pb by S. putrefaciens CN32 observed in this study provides potential new insight into the biogeochemical cycling of Pb in reducing environments.
黄钾铁矾（MFe(3)(SO(4))(2)(OH)(6)）在锌工业的萃取过程中沉淀以去除杂质，并且含有铅和银等金属。黄钾铁矾废料通常被限制在加盖的尾矿池中，因此存在被微生物群体进行厌氧还原溶解的可能性。本研究通过在厌氧近中性条件下进行的批次实验，证明了一种地下异化铁还原细菌（腐败希瓦氏菌CN32）对合成铅黄钾铁矾（PbFe(6)(SO(4))(4)(OH)(12)）的还原溶解作用。随着时间的推移监测了溶液化学、pH值、氧化还原电位（Eh）和细胞活力，结果表明从铅黄钾铁矾释放的结构铁（III）被还原为铁（II）。含有铅黄钾铁矾的接种样品也显示细胞活力下降，同时铅浓度增加。扫描电子显微镜（SEM）图像显示细菌表面有电子致密纳米颗粒的逐步成核，通过透射电子显微镜/能谱仪（TEM/EDS）鉴定为富含铅和磷的细胞内结晶沉淀。本研究中观察到的腐败希瓦氏菌CN32对铅的细胞内沉淀作用，为还原环境中铅的生物地球化学循环提供了潜在的新见解。
