Role of microbiogeochemical processes in mobilization of As in the aquifer sediments of the Bengal Delta Plain (BDP): an experimental approach

在孟加拉三角洲平原（BDP），由于长期饮用高砷含量的地下水，数百万人受到慢性砷中毒的影响。尽管在理解这场灾难背后的地球化学过程中取得了进展，但地下水中高As浓度的最终原因仍不清楚，阻碍了有效缓解措施的实施。有一个受过教育的猜测，细菌和相关的生物地球化学过程中可能发挥了关键作用，动员作为从含水层沉积物，但这一假设的有效性仍然在很大程度上未经探索，直到现在。拟议的项目旨在通过微生物学家、地球化学家、地质学家和化学家在联合实验室和现场实验中的协同合作，评估和量化微生物在这一过程中的作用。含水层沉积物和地下水收集的两个钻孔在高和低的网站将地球化学和微生物的特点和材料将被用于柱实验，以调查动员的氧化还原过程中介导的不同菌株的微生物。现场实验包括抽水和注入试验，再加上水化学监测超过2年的目的是破译复杂的相互作用之间的广泛的水开采，含水层曝气，微生物活动，和高砷含量的地下水。

In the Bengal Delta Plain (BDP) millions of people are exposed to chronic As poisoning due to prolonged consumption of groundwater with high As contents. Despite progresses in understanding the geochemical processes behind this calamity, the ultimate cause of the high As concentrations in groundwater is still unclear, impeding the implementation of efficient mitigation measures. There is an educated guess that bacteria and related biogeochemical processes may play a key role in the mobilization of As from the aquifer sediments, but the validity of this hypothesis remained largely unexplored until now. The proposed project aims to assess and quantify the role of microbes in this process by a synergetic co-operation among microbiologists, geochemists, geologists and chemists in joint laboratory and field experiments. Aquifer sediments and groundwater collected from two drillings at a high and a low As site will be geochemically and microbiologically characterized and the material will be used in column experiments to investigate the mobilization of As during redox processes mediated by different strains of microbes. Field experiments consisting of pumping and injection tests coupled with a hydrochemical monitoring over 2 years aim at deciphering the complex interaction among extensive water exploitation, aquifer aeration, microbial activity, and high As contents in groundwater.