Doctoral Dissertation Enhancement Project: Deciphering Arsenic Migration Pathways within the Mekong Delta, Cambodia

Stanford University, Stanford CA

Investigators

Abstract

0751701 Fendorf This award supports a doctoral dissertation enhancement project between Dr. Scott Fendorf, his student and Dr. Michael Sampson, Director, Resource Development International in Phnom Penh, Cambodia. The project will involve deciphering Arsenic migration pathways within the Mekong Delta in Cambodia. Arsenic, a toxic and carcinogenic metalloid found throughout the earth's crust, is adversely affecting millions of individuals worldwide. Many individuals in Southeast Asia are exposed to drinking water contaminated with arsenic. Despite the widespread poisoning and resulting attention on subsurface arsenic sources, biophysicochemical processes leading to Arsenic groundwater remain unresolved. The researchers propose to define the processes responsible for releasing Arsenic into the aqueous phase within the sedimentary basins of Southeast Asia. The Mekong Delta of Cambodia will serve as a model system for the study. In accomplishing this project they will utilize a suite of field measurements, intact core leaching experiments, and sediment incubations with native microbial communities. Once completed, they will provide a specific illustration of arsenic release and transport within sediments, which will constrain predictions of where Arsenic is a problem contaminant. Such predictions are desperately needed to combat the current health crisis associated with the widespread ingestion of arsenic contaminated waters, especially in the developing nations of Southeast Asia. The results of this study will provide a mechanistic description of Arsenic release from near-surface tropical sediments, inclusive of relevant biological, chemical, and hydrologic processes. The biochemical conditions with sediments conductive to Arsenic release will be constrained, and this disseminated information will be used to better predict locations which may be at higher risk of elevated Arsenic concentrations within Southeast Asia. The project will train the U.S. graduate student, as well as some young Cambodian scientists, to acquire and analyze field data, adding to the intellectual base now depleted by many years of the civil war. The project will also provide the U.S. graduate student with a global research experience. It is anticipated that the student will maintain scientific connections with his Cambodian collaborators for many years after the project is completed.