Abstract

Arsenic contamination of groundwaters in South/Southeast Asia is a major threat to public health. Understanding
the source and age of the groundwaters is critically important to understanding the controls on arsenic mobilization in these aquifers. Utilizing a suite of isotopic tracers, we have determined various site-specific recharge mechanisms, and estimated recharge source contributions. Tritium-helium age determinations show that the groundwater in this area is modern, indicating relatively fast recharge even in the absence of large-scale groundwater abstraction. The relationship between apparent age and depth indicates a strong vertical control on hydrology, which may influence preferential flow paths and ultimately arsenic release in these aquifers.