title: Process-based reactive transport model to quantify arsenic mobility during aquifer storage and recovery of potable water.
abstract: Aquifer storage and recovery (ASR) is an aquifer recharge technique in which water is injected in an aquifer during periods of surplus and withdrawn from the same well during periods of deficit. It is a critical component of the long-term water supply plan in various regions, including Florida, USA. Here, the viability of ASR as a safe and cost-effective water resource is currently being tested at a number of sites due to elevated arsenic concentrations detected during groundwater recovery. In this study, we developed a process-based reactive transport model of the coupled physical and geochemical mechanisms controlling the fate of arsenic during ASR. We analyzed multicycle hydrochemical data from a well-documented affected southwest Floridan site and evaluated a conceptual/numerical model in which (i) arsenic is initially released during pyrite oxidation triggered by the injection of oxygenated water (ii) then largely complexes to neo-formed hydrous ferric oxides before (iii) being remobilized during recovery as a result of both dissolution of hydrous ferric oxides and displacement from sorption sites by competing anions.
authors: School of the Environment, Flinders University, Adelaide, GPO Box 2100, SA 5001, Australia. ilka.wallis@csiro.au
authors: Ilka
authors: I
authors: Wallis
authors: Henning
authors: H
authors: Prommer
authors: Thomas
authors: T
authors: Pichler
authors: Vincent
authors: V
authors: Post
authors: Stuart B
authors: SB
authors: Norton
authors: Michael D
authors: MD
authors: Annable
authors: Craig T
authors: CT
authors: Simmons
mesh_terms: D001151:Arsenic / Q000032:analysis*; D002138:Calibration; D003198:Computer Simulation; D060766:Drinking Water / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D009038:Motion; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis; D013997:Time Factors; D035501:Uncertainty; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification; D014881:Water Supply / Q000032:analysis*
chemical_list: D060766:Drinking Water; D014874:Water Pollutants, Chemical; D001151:Arsenic; D010100:Oxygen