Role of competing ions in the mobilization of arsenic in groundwater of Bengal Basin: Insight from surface complexation modeling

Biswas, Ashis; Gustafsson, Jon-Petter; Neidhardt, Harald; Halder, Dipti; Kundu, Amit K.; Chatterjee, Debashis; Berner, Zsolt; Bhattacharya, Prosun

doi:10.1016/j.watres.2014.02.002

Research article2014Peer reviewedOpen access

Role of competing ions in the mobilization of arsenic in groundwater of Bengal Basin: Insight from surface complexation modeling

Biswas, Ashis; Gustafsson, Jon-Petter; Neidhardt, Harald; Halder, Dipti; Kundu, Amit K.; Chatterjee, Debashis; Berner, Zsolt; Bhattacharya, Prosun

Abstract

This study assesses the role of competing ions in the mobilization of arsenic (As) by surface complexation modeling of the temporal variability of As in groundwater. The potential use of two different surface complexation models (SCMs), developed for ferrihydrite and goethite, has been explored to account for the temporal variation of As(III) and As(V) concentration, monitored in shallow groundwater of Bengal Basin over a period of 20 months. The SCM for ferrihydrite appears as the better predictor of the observed variation in both As(III) and As(V) concentrations in the study sites. It is estimated that among the competing ions, PO4^3-is the major competitor of As(III) and As(V) adsorption onto Fe oxyhydroxide, and the competition ability decreases in the order PO4^3- >> Fe(II) > H4SiO4 = HCO^-(3.) It is further revealed that a small change in pH can also have a significant effect on the mobility of As(III) and As(V) in the aquifers. A decrease in pH increases the concentration of As(III), whereas it decreases the As(V) concentration and vice versa. The present study suggests that the reductive dissolution of Fe oxyhydroxide alone cannot explain the observed high As concentration in groundwater of the Bengal Basin. This study supports the view that the reductive dissolution of Fe oxyhydroxide followed by competitive sorption reactions with the aquifer sediment is the processes responsible for As enrichment in groundwater. (C) 2014 Elsevier Ltd. All rights reserved.

Keywords

Bengal Basin; Groundwater; Arsenic mobilization; Temporal variability; Competing ions; Surface complexation modeling

Published in

Water Research
2014, volume: 55, pages: 30-39
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

Gustafsson, Jon-Petter
- Department of Soil and Environment, Swedish University of Agricultural Sciences

Global goals (SDG)

SDG6 Clean water and sanitation

UKÄ Subject classification

Geochemistry

Publication identifier

DOI: https://doi.org/10.1016/j.watres.2014.02.002

Permanent link to this page (URI)

https://res.slu.se/id/publ/56125