Zhang Lin, Lu Jin-Suo
School of Environmental and Municipal Engineering, Xi'an University of Architecture & Technology, Xi'an 710055, China.
Huan Jing Ke Xue. 2017 Sep 8;38(9):3937-3943. doi: 10.13227/j.hjkx.201701115.
Soil contamination with co-existing arsenic (As) and antimony (Sb) has become a serious environmental problem worldwide. Microorganisms play a dominant role in the redox transformation and mobilization of As and Sb. As and Sb belong to the same family; they are alike in nature and have related microbial oxidation-reduction mechanisms. However, limited knowledge is available about the impact of As-reducing bacteria on the fate of As and Sb in their co-existing soils. The purpose of this study was to explore the redox transformation and release of As and Sb in the presence of an carrier, sp. IMH, which has high As(Ⅴ)-reducing capability. In addition to the IMH incubation system, the dead cell system and abiotic control experiments were conducted. The results showed that the IMH incubation reduced all soluble As(Ⅴ) (72.7 μg·L) to As(Ⅲ) form, whereas soluble Sb(Ⅴ) (364.8 μg·L) was not reduced, indicating that the As (V)-reducing pathway mediated by genesis was not able to reduce Sb(Ⅴ). The amounts of total As (506.8 μg·L) and total Sb (821.1 μg·L) in the dead cell system were approximately four times higher than in the living cell system (As=155.2 μg·L; Sb=364.8 μg·L) and the abiotic control (As=57.6 μg·L; Sb=271.1 μg·L) because of the biomolecules released from the dead cells which enhanced the release of As and Sb. The correlation analysis of dissolved As and Sb showed that the release of total As and Sb was correlated (<0.05) in three systems. Our study shed new light on the impact of bacteria on the fate of As and Sb in soils.
土壤中砷（As）和锑（Sb）共存造成的污染已成为全球严重的环境问题。微生物在砷和锑的氧化还原转化及迁移中起主导作用。砷和锑属于同一家族；它们性质相似且具有相关的微生物氧化还原机制。然而，关于砷还原菌对共存土壤中砷和锑归宿的影响，目前了解有限。本研究的目的是探究在具有高砷（Ⅴ）还原能力的嗜铁钩端螺旋菌（Leptospirillum ferriphilum）sp. IMH存在的情况下，砷和锑的氧化还原转化及释放情况。除了IMH培养系统外，还进行了死细胞系统和非生物对照实验。结果表明，IMH培养将所有可溶性砷（Ⅴ）（72.7μg·L）还原为砷（Ⅲ）形态，而可溶性锑（Ⅴ）（364.8μg·L）未被还原，这表明由嗜铁钩端螺旋菌介导的砷（Ⅴ）还原途径无法还原锑（Ⅴ）。由于死细胞释放的生物分子增强了砷和锑的释放，死细胞系统中总砷（506.8μg·L）和总锑（821.1μg·L）的含量大约是活细胞系统（砷=155.2μg·L；锑=364.8μg·L）和非生物对照（砷=57.6μg·L；锑=271.1μg·L）中的四倍。溶解态砷和锑的相关性分析表明，在三个系统中总砷和总锑的释放具有相关性（<0.05）。我们的研究为细菌对土壤中砷和锑归宿的影响提供了新的见解。
