Contrasting sorption behaviours affecting groundwater arsenic concentration in Kandal Province,Cambodia

作     者：Laura A. Richards Maria J. Casanueva-Marenco Daniel Magnone Chansopheaktra Sovann Bart E. van Dongen David A. Polya 

作者机构：School of Earth and Environmental Sciences and Williamson Research Centre for Molecular Environmental ScienceThe University of ManchesterWilliamson BuildingOxford RoadManchesterM13 9PLUK Department of Analytical ChemistryInstitute of BiomoleculesFaculty of SciencesUniversity of CádizCádizSpain School of GeographyUniversity of LincolnBrayford PoolLincolnLincolnshireLN6 7TSUK Department of Environmental ScienceRoyal University of Phnom PenhPhnom PenhCambodia 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2019年第10卷第5期

页      面：1701-1713页

核心收录：

学科分类：07[理学] 

基　　金：funded by a NERC(Natural Environment Research Council, UK) Standard Research Grant(NE/J023833/1)to DAP, BEvD and C.J.Ballentine(now at University of Oxford) a NERC PhD studentship(NE/L501591/1) to DM receipt of a University of Cadiz(UCA) Postdoctoral Bridge Contract award the support of The Leverhulme Trust (UK)(ECF2015-657) 

主　　题：Arsenic Groundwater Partial equilibrium Sorption Water-rock interactions Cambodia 

摘      要：Natural arsenic (As) contamination of groundwater which provides drinking water and/or irrigation supplies remains a major public health issue,particularly in South and Southeast Asia.A number of studies have evaluated various aspects of the biogeochemical controls on As mobilization in aquifers typical to this region,however many are predicated on the assumption that key biogeochemical processes may be deduced by sampled water *** validity of this assumption has not been clearly established even though the role of sorption/desorption of As and other heavy metals onto Fe/Mn (hydr) oxides is an important control in As ***,selective chemical extractions of sand-rich and clay-rich sediments from an As-affected aquifer in Kandal Province,Cambodia,were undertaken to explore the potential role of partial re-equilibrium through sorption/desorption reactions of As and related solutes (Fe,Mn and P) between groundwater and the associated solid aquifer *** general,groundwater As is strongly affected by both pH and Eh throughout the study ***,contrasting sorption behaviour is observed in two distinct sand-dominated (T-Sand) and clay dominated (T-Clay) transects,and plausibly attributed to differing dominant lithologies,biogeochemical and/or hydrogeological ***/desorption processes appear to be re-setting groundwater As concentrations in both transects,but to varying extents and in different *** T-Sand,which is typically highly reducing,correlations suggest that dissolved As may be sequestered by sorption/re-adsorption to Fe-bearing mineral phases and/or sedimentary organic matter;in T-Clay Eh is a major control on As mobilization although binding/occlusion of Fe-bearing minerals to sedimentary organic matter may also *** linear regression analysis was conducted with groups categorised by transect and by Eh,and the output correlations support the contrasting sorption behaviours encountered in this study area.I