Issue 8, 2016

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

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

Supplementary files

Article information

Article type
Paper
Submitted
16 юни 2016
Accepted
18 юли 2016
First published
19 юли 2016

Environ. Sci.: Processes Impacts, 2016,18, 1090-1103

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

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements