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Arsenic in Groundwater of Asia               

               

Project:  Deciphering Processes Responsible for the Arsenic-Induced Largest Mass Poisoning in History
Primary researchers:  Ben Kocar, Matt Polizzotto, Jason Stuckey, Sam Ying, Shawn Benner (Boise State Univ.), Scott Fendorf

As many as one hundred million people living in the large river deltas of South and Southeast Asia (e.g., West Bengal India, Bangladesh, Cambodia, Myanmar, and Vietnam) routinely consume well water with unsafe arsenic levels (often 20 to 50 times, and up to more than 100 times, the recommended limit set by the World Health Organization). While there is general agreement that arsenic is naturally derived, the processes governing aqueous concentrations in groundwater remain unresolved, limiting our ability to predict arsenic concentrations in space (between wells) and time (future concentrations) and to assess the impact of human activities on the arsenic problem. Long-term exposure to high levels of arsenic has resulted in arsenicosis and cancers. However, because most surface water sources are contaminated with pathogens, people continue to drink well water, forced to choose arsenic poisoning over surface water-borne (pathogen) diseases.

In our field work, we seek to determine the hydrologic and biogeochemical processes operative within the aquifer systems of Asia.  Integrating our knowledge gained from laboratory studies with a determination of the field conditions, we aim to develop the capacity to predict, spatially and temporally, shifts in groundwater arsenic concentration with land use change (e.g., irrigation, development, river alterations).  

Our main research area is in the Mekong River Delta of Cambodia where we have established an approximately 50 square kilometer site in partnership with Resource Development International, Cambodia. We are continuing to measure the distribution of chemical parameters (including arsenic) of groundwater and surface water, monitored hydraulic heads to establish groundwater flow paths, and analyzed soils and sediments in order to understand the sources and controls on arsenic in groundwater.  We are paralleling these efforts with detail biogeochemical studies of soils and near-surface sediments, and with an analysis of land use changes (current and impending). 

   ->Scott Fendorf featured in July 24th Nature Podcast <- Click to listen

Publications:

Benner, S.G., M.L. Polizzotto, B. D. Kocar, S. Ganguly, K. Phan, K. Ouch, M. Sampson, and S. Fendorf. 2008. Groundwater flow in an arsenic-contaminated aquifer, Mekong Delta, Cambodia.  Appl. Geochem.  23: 30723087.

Kocar, B.D., M.L. Polizzotto, S.G. Benner, S. Ying, M. Ung, K. Ouch, S. Samreth, B. Suy, K. Phan, M. Sampson, and S. Fendorf. 2008. Integrated biogeochemical and hydrologic processes driving arsenic release from shallow sediments to groundwaters of the Mekong Delta.  Appl. Geochem.  23: 3059-3071.

Polizzotto, M. L., S. G. Benner, B. D. Kocar, M. Sampson, and S. Fendorf.  2008.  Near-surface wetland sediments as a source of arsenic release to groundwater in Asia.  Nature  454: 505-508.

Polizzotto, M. L., C. F. Harvey, G.-C. Li, B. Badruzzman, M. Newville, and S. Fendorf.  2006. Solid-phases and desorption processes of arsenic within Bangladesh sediments.   Chemical Geology.  228: 97-111.

Polizzotto, M. L., C. F. Harvey, S. R. Sutton, and S. Fendorf. 2005.  Processes conducive to the release and transport of arsenic into aquifers of Bangladesh.  Proc. Nation. Acad. Sci.  102: 18819-18823.


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