Effect of irrigation on Fe(III)–SO42− redox cycling and arsenic mobilization in shallow groundwater from the Datong basin, China: Evidence from hydrochemical monitoring and modeling

摘要: Summary Seasonal hydrochemical monitoring has been conducted at a well-known arsenic (As) contaminated site to understand the critical controlling processes on As mobilization and enrichment in groundwater. The results indicate that water chemistry studied is mainly controlled by evaporates dissolution, redox reactions during irrigation non-irrigation periods, respectively. measured redox-sensitive components groundwater experienced periodic changes from periods an enhanced reducing environment prevailed period. observed high concentration strong positive correlation between Fe support conclusion oxides/hydroxides reduction sulfide oxidation releases However, relatively low close inverse As, SO 4 2− show Fe(III) accompanied formation of precipitates, retains periods. geochemical modeling performed for selected wells confirms oxide/hydroxide dissolution as well siderite precipitation are dominant related evolution pre-irrigation period, while immobilize post-irrigation In general, combined Fe(III)–SO cycling induced practices controls this site.