Mekong Delta - Groundwater Arsenic Occurrence and Land Subsidence

Project Leads

Laura Erban
Steven Gorelick
Howard Zebker and Scott Fendorf

Student capturing water samples from pipe

In the Mekong Delta, millions rely on a groundwater system that is widely contaminated with arsenic. As in similarly arsenic-affected river basins throughout Southeast Asia, untreated groundwater is widely self-provisioned by the rural poor. Reliance on the Delta’s groundwater resources continues to rise in both rural and urban areas, in step with societal welfare improvements of the post-conflict period. While groundwater exploitation is, in some ways, beneficial to current development in the Delta, it is also introducing large populations to new risks, among them to exposure to arsenic.

This body of research covers two topics. The first is analysis of the spatial variability of groundwater arsenic in Vietnam based on an unprecedented data set of over 42,000 measurements collected by the Vietnamese government. Our published analysis shows the spatial patterns of and information about the probability of occurrence arsenic contaminated groundwater. In addition, deep arsenic (~300 m) over a 1000 sq. km. region was discovered in violation of the drinking water standard, and we proposed a yet unknown mechanism that explains this occurrence. In addition, we analyzed the coupled impacts of land subsidence due to excessive groundwater pumping and projected sea level rise to evaluate the future inundation hazard in Vietnam.

Publications
Erban, L.E., S.M. Gorelick, and H.A. Zebker, 2014, Groundwater extraction, land subsidence, and sea-level rise in the Mekong Delta, Vietnam. Environmental Research Letters, 9 (8), 084010, doi:10.1088/1748-9326/9/8/084010

Erban, L., S.M. Gorelick, and S. Fendorf, 2014, Arsenic in the multi-aquifer system of the Mekong Delta, Vietnam: Analysis of large-scale spatial trends and controlling factors, Environmental Science and Technology, 48 (11), pp. 6081-6088, doi/, 48 (11), pp 6081–6088 doi/10.1021/es403932t

Erban, L., S.M. Gorelick, H.A. Zebker, and S. Fendorf, 2013, Release of arsenic to deep groundwater in the Menkong Delta, Vietnam, linked to pumping-induced land subsidence, Proc. National Academy of Sciences, doi/10.1073/pnas.1300503110