Jump to main content
Jump to site search

Issue 8, 2016
Previous Article Next Article

Chemical controls on abiotic and biotic release of geogenic arsenic from Pleistocene aquifer sediments to groundwater

Author affiliations

Abstract

Over 150 million people in South and Southeast Asia consume unsafe drinking water from arsenic-rich Holocene aquifers. Although use of As-free water from Pleistocene aquifers is a potential mitigation strategy, such aquifers are vulnerable to geogenic As pollution, placing millions more people at potential risk. The goal of this research was to define chemical controls on abiotic and biotic release of geogenic As to groundwater. Batch incubations of sediments with natural chemical variability from a Pleistocene aquifer in Cambodia were conducted to evaluate how interactions among arsenic, manganese and iron oxides, and dissolved and sedimentary organic carbon influenced As mobilization from sediments. The addition of labile dissolved organic carbon produced the highest concentrations of dissolved As after >7 months, as compared to sediment samples incubated with sodium azide or without added carbon, and the extent of As release was positively correlated with the percent of initial extractable Mn released from the sediments. The mode of As release was impacted by the source of DOC supplied to the sediments, with biological processes responsible for 81% to 85% of the total As release following incubations with lactate and acetate but only up to 43% to 61% of the total As release following incubations with humic and fulvic acids. Overall, cycling of key redox-active elements and organic-carbon reactivity govern the potential for geogenic As release to groundwater, and results here may be used to formulate better predictions of the arsenic pollution potential of aquifers in South and Southeast Asia.

Graphical abstract: Chemical controls on abiotic and biotic release of geogenic arsenic from Pleistocene aquifer sediments to groundwater

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 16 Jun 2016, accepted on 18 Jul 2016 and first published on 19 Jul 2016


Article type: Paper
DOI: 10.1039/C6EM00359A
Citation: Environ. Sci.: Processes Impacts, 2016,18, 1090-1103
  •   Request permissions

    Chemical controls on abiotic and biotic release of geogenic arsenic from Pleistocene aquifer sediments to groundwater

    E. C. Gillispie, E. Andujar and M. L. Polizzotto, Environ. Sci.: Processes Impacts, 2016, 18, 1090
    DOI: 10.1039/C6EM00359A

Search articles by author