1.State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,China;2.State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment,Beijing Normal University,Beijing,China;3.Institute for Global Food Security, School of Biological Sciences,Queen’s University Belfast,Belfast,UK;4.Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,China;5.Key Laboratory of Urban Environment and Health, Institute of Urban Environment,Chinese Academy of Sciences,Xiamen,China
Abstract:
Arsenic (As) is a pervasive environmental toxin and carcinogenic metalloid. It ranks at the top of the US priority List of Hazardous Substances and causes worldwide human health problems. Wetlands, including natural and artificial ecosystems (i.e. paddy soils) are highly susceptible to As enrichment; acting not only as repositories for water but a host of other elemental/chemical moieties. While macroscale processes (physical and geological) supply As to wetlands, it is the micro-scale biogeochemistry that regulates the fluxes of As and other trace elements from the semi-terrestrial to neighboring plant/aquatic/atmospheric compartments. Among these fine-scale events, microbial mediated As biotransformations contribute most to the element’s changing forms, acting as the ‘switch’ in defining a wetland as either a source or sink of As. Much of our understanding of these important microbial catalyzed reactions follows relatively recent scientific discoveries. Here we document some of these key advances, with focuses on the implications that wetlands and their microbial mediated transformation pathways have on the global As cycle, the chemistries of microbial mediated As oxidation, reduction and methylation, and future research priorities areas.
