高砷地下水系统中铁还原菌及其铁还原-砷释放的生物地球化学动力学

Geogenic high arsenic (As) groundwater is a worldwide environmental geological issue and attracting sustained attention of the international hydrogeological community. The formation process of high arsenic groundwater is closely related to the activity of iron reducing bacteria. However, both the distribution of the active iron reducing bacteria that determines the reduction of iron oxide minerals in the high arsenic aquifer and the interaction between the indigenous active iron reducing bacteria and iron oxide minerals are poorly understood. We select the Hangjinhouqi area in Inner Mongolia, a typical geogenic As contaminated aquifer in China, as the research area. Based on systematic investigation of groundwater chemistry and sediment geochemistry, and metatranscriptome analysis of community structure of active iron reducing bacteria, key groups of active iron reducing bacteria and its key environmental control factors can be obtained. The reduction of different As-bearing iron oxide minerals and characteristics of arsenic release kinetics during enrichment culture of key groups of iron reducing bacteria in both laboratory and in situ environment will be investigated to illuminate the dynamic character of As release induced be the key groups of active iron reducing bacteria. This research not only enhances the understanding of the mechanism of arsenic enrichment in groundwater, but also provides important basic data and scientific evidence for the prediction and treatment of high arsenic groundwater, as well as the planning and management of water resources .

原生高砷地下水是国际水文地质界持续关注的重大环境地质问题,其形成过程与铁氧化物矿物的还原密切相关。然而对于决定铁氧化物矿物还原的活性铁还原菌在高砷含水层中的分布、活性铁还原菌-铁氧化物矿物相互作用及动力学特征却并不清楚。这些科学问题的揭示有利于从根本上解决高砷地下水形成机理的难题。项目以内蒙古河套盆地为研究区，拟深入调查高砷地下水的水化学特性和沉积物特征，通过宏转录组学获得活性铁还原菌优势类群，确定对砷分布起决定作用的活性铁还原菌关键类群及关键环境控制因子。针对活性铁还原菌关键类群进行实验室微环境的富集培养，并结合现场原位实验，探究活性铁还原菌关键类群作用下不同铁氧化物矿物还原和砷释放动力学特征。该研究不仅加深对地下水富砷机理的理解，也是为原生高砷地下水的预测和治理，水资源规划与管理等提供重要的基础资料和科学依据。

原生高砷地下水是国际水文地质界持续关注的重大环境地质问题,其形成过程与铁氧化物矿物的还原密切相关。然而对于决定铁氧化物矿物还原的活性铁还原菌在高砷含水层中的分布、活性铁还原菌-铁氧化物矿物相互作用及动力学特征却并不清楚。这些科学问题的揭示有利于从根本上解决高砷地下水形成机理的难题。项目以内蒙古河套盆地为研究区，调查了高砷地下水的水化学特性和沉积物特征，通过分析地下水和沉积物微生物基因组特征、总微生物和活性铁还原菌优势类群等，获得以下主要结论：（1）发现地下水和沉积物中的活性砷和铁还原微生物群落均可驱动含水层砷的富集，但地下水中砷铁还原相关活性微生物可能是决定地下水砷富集程度的关键；（2）微生物作用下砷的还原和含砷铁矿物的还原性溶解导致砷迁移，但氨氧化铁还原可能是被忽略的导致地下水砷富集的重要机制；（3）活性铁还原微生物介导下高砷地下水沉积物和不同成因的富砷铁氧化物的铁还原和砷释放动力学特征表明，生物成因铁矿物形成的还原可显著提高砷的在含水层的迁移。该研究不仅加深对地下水富砷机理的理解，也是为原生高砷地下水的预测和治理，水资源规划与管理等提供重要的基础资料和科学依据。