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

地下水中天然存在的砷（As）污染在墨西哥、中国、匈牙利、阿根廷、智利、柬埔寨、印度（西孟加拉）和孟加拉国等国家造成了全球公共卫生危机，并被称为人类历史上“最大规模的中毒”。这些沉积物中砷的释放机制一直是国际上激烈争论的话题。然而，微生物介导的减少组合物包括砷（最有可能作为砷酸盐）吸附到羟基氧化铁已获得共识，作为最有可能的方法动员砷进入这些地下水，虽然确切的释放机制仍有待确定。关键问题包括：（i）催化该过程的生物体的身份;（ii）导致电子转移到细胞外Fe/As矿物组合的生理机制;（iii）Fe/As矿物组合的性质。活化金属还原和释放的有机材料的释放（和递送途径）;以及（iv）其它竞争过程如氧化、硫化和吸附之间的相互作用，这些过程可在原位削弱该过程。通过将尖端微生物学，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计划，旨在确定导致这种环境灾难的关键分子尺度因素，同时通知战略，以尽量减少其影响。一个成熟的国际合作网络将支持我们的现场相关活动，转移分子尺度数据，为水文地球化学模型提供信息，并随后与孟加拉国和柬埔寨等国家的主要利益相关者进行知识交流。

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.