Genetic and molecular basis of organic-arsenic-microbe interactions in arsenic prone aquifers (GOAM)

地下天然存在的砷污染地下水，在墨西哥、中国、匈牙利、阿根廷、智利、柬埔寨、印度（西孟加拉邦）和孟加拉国等国造成了全球公共卫生危机，并被称为人类历史上“最大的集体中毒”。砷从这些沉积物中释放的机制一直是国际上激烈争论的话题。然而，微生物介导的由砷（最有可能是砷酸盐）吸附到铁氧氢氧化物的组合的还原已经获得共识，这是将砷动员到这些地下水中最可能的方法，尽管释放的确切机制仍有待确定。仍然存在的关键问题包括：(i)催化该过程的生物的身份；（ii）导致电子向细胞外Fe/As矿物组合转移的生理机制；（iii）激活金属还原和释放的有机物质的性质（和输送途径）；（iv）其他相互竞争的过程之间的相互作用，如氧化、硫化和吸附，这些过程可以在原位减弱过程。通过将前沿微生物学、高通量分子生态学（元组学）、地球化学和矿物学技术与直接从两个高砷地下水对比现场获得的样品相结合，GOAM是一个假设驱动的研究项目，旨在确定导致这种环境灾难的关键分子尺度因素，同时为最小化其影响的策略提供信息。一个成熟的国际合作网络将为我们的实地相关活动、为水文地球化学模型提供分子尺度数据的转移以及随后与孟加拉国和柬埔寨等国的主要利益攸关方的知识交流提供支持。

Contamination of groundwater from naturally occurring arsenic (As) in the subsurface poses a global public health crisis in countries including Mexico, China, Hungary, Argentina, Chile, Cambodia, India (West Bengal), and Bangladesh and has been termed "the largest mass poisoning" in human history. The mechanism of arsenic release from these sediments has been a topic of intense international debate. However, microbially-mediated reduction of assemblages comprising arsenic (most likely as arsenate) sorbed to ferric oxyhydroxides has gained consensus as the most likely method of mobilization of arsenic into these groundwaters, although the precise mechanism of release remains to be identified. Critical questions that remain include (i) the identity of the organisms that catalyse the process; (ii) the physiological mechanism that leads to electron transfer to the extracellular Fe/As mineralogical assemblage; (iii) the nature (and delivery route) of the organic material that activates metal reduction and release; and (iv) the interplay between other competing processes such as oxidation, sulfidation and sorption that can attenuate the process in situ. By focusing the combination of cutting edge microbiological, high throughput molecular ecology (meta-omics), geochemical and mineralogical techniques against samples obtained directly from two contrasting field sites with high arsenic groundwaters, GOAM is a hypothesis driven research programme that aims to identify the critical molecular scale factors causing this environmental disaster, while informing strategies to minimise their impact. A mature network of international collaborations will underpin our field related activities, transfer of molecular scale data to inform hydrogeochemical models and subsequent knowledge exchange with key stakeholders in countries including Bangladesh and Cambodia.