Collaborative Research: Enhancing the Sustainability of Groundwater Pumping from Low-Arsenic Aquifers in Southern Asia - A Case-study in Vietnam South of Hanoi
DESCRIPTION: Analytical methods will be used to better determine whether dissolved or particulate organic carbon drives microbial dissolution of Fe oxyhydroxides and to what extent absorption and precipitation of As attenuate the impact of high-As water drawn into low-As aquifers. The methods will include 14C-analysis of phospholipid fatty acids, 3H-3He dating, and optically-stimulated luminescence dating of quartz.
OUTCOMES: Found evidence that DOC may modify the redox state of Fe oxides on a significant scale and therefore the release of As. Also found that orange sands seem to be converted to grey by As advection. The As front in Van Phuc moves 10-20 times more slowly than the water. Found that sandy aquifers more than 10,000 years old generally don't have high-As ground water, unlike younger ones.