Peter Knappett, assistant professor of hydrogeology at Texas A&M, and colleagues have had their work published in the current issue of Nature Communications. This publication represents what their team of scientists have accomplished in the most recent first four years of a sixteen year major project. Knappett has been going to Bangladesh since 2008 to conduct his research.

Many of the world’s megacities depend on groundwater from aquifers that are threatened by contamination. A team of international scientists, and our own Texas A&M researcher, Dr. Peter Knappett, have studied groundwater pumping under urban landscapes and how it poses drinking water contamination problems that have the potential to kill millions of people. The group focused on the widespread naturally occurring arsenic in shallow deltas of the Ganges-Bramhaputra-Meghna river delta in aquifers underlying Dhaka, the capital of Bangladesh. With a large population, like the 15 million people in Dhaka, intense pumping occurs may pull the arsenic-contaminated shallow groundwater down into deep groundwater. The intensive urban pumping will cause the toxic shallow and deep groundwater to mix. Dhaka shares many of the water management problems common to other major cities.

Using computer models and field observations, the team is demonstrating how important it is for Dhaka to minimize their impact on deep aquifer water levels by slowing their pumping rates and installing wells that are farther away from the city, as well as develop the capacity to treat abundant surface water for drinking. In general, intensive urban groundwater pumping can cause an incredible amount of change in the chemistry of the aquifer, in some cases making it toxic to drink. Cities can deplete the quantity and quality of water through numerous sources of pollution, as they have a regional footprint.

Future research in the study area will include monitoring water levels and water chemistry and studying how this will impact the area in terms of viable water sources for drinking and human exposure to arsenic. The study was funded by the National Institutes for Environmental Health Superfund Research Program.

Journal Reference:

Mahfuzur R. Khan, Mohammad Koneshloo, Peter S. K. Knappett, Kazi M. Ahmed, Benjamin C. Bostick, Brian J. Mailloux, Rajib H. Mozumder, Anwar Zahid, Charles F. Harvey, Alexander van Geen, Holly A. Michael. Megacity pumping and preferential flow threaten groundwater quality. Nature Communications, 2016; 7: 12833 DOI: 10.1038/ncomms12833