Superfund Research Program

Hydrogeology Core

Project Leader: Alexander F. van Geen
Grant Number: P42ES010349
Funding Period: 2000-2021

Project-Specific Links

Final Progress Reports

Year:   2020  2016  2010  2005 

Detailed knowledge of groundwater flow is essential for understanding geochemical processes in the subsurface. Identification of recharge and discharge areas and mechanisms, as well as flow lines are essential for delineating trends in geochemical evolution, including changes in arsenic concentrations, and to quantify reaction rates. Depressurization of the deep, low-arsenic aquifer below our study area of Araihazar in Bangladesh by massive pumping for the municipal water supply of Dhaka has been the focus of research supported under the Hydrogeology Core Laboratory. The research team has shown that the vast majority of 900+ deep community wells installed throughout Araihazar currently provide water which meets the WHO guideline for arsenic in drinking water (Mihajlov et al., 2016; van Geen et al. 2016) but this may not remain the case. Some deep wells can no longer be used by the local population with a simple hand-pump because of the cone depression extending east of Dhaka (Knappett et al., 2016). Researchers have also shown that vertical head gradients resulting from Dhaka pumping could potentially induce downward flow of shallow high-arsenic groundwater (Khan et al., 2016). Conversely, research conducted with support from the Hydrogeology Core Laboratory demonstrated with leak tests and deployments of a downhole camera that only a small proportion of deep wells in the HEALS area have been improperly installed (Choudhury et al., 2016). This core also supported the analysis of 30 groundwater samples for tritium and over 1500 samples for the stable isotopes of hydrogen and oxygen.