Abstract
Arsenic contaminated groundwater is poisoning millions of people in Bangladesh and West Bengal in what is generally agreed to be the "largest mass poisoning in human history." Becca has produced groundbreaking results from her research in Bangladesh where she has recently directed a field program directed towards understanding and solving the arsenic contamination problem. Becca constructed a system of sensors at a field site in Bangladesh to investigate how biogeochemical and hydrologic processes control the concentration of arsenic in recharge to aquifers that supply drinking-water wells. Becca designed and built the sensor system from the electronics, through field-installation, to chemical analysis. She found that contaminated groundwater originates from constructed ponds -- infiltration through the sediments on the bottom of ponds carries dissolved organic carbon into the aquifer where it drives the biogeochemical processes that liberate arsenic from sediments that compose the aquifer. Becca demonstrated that, in contrast to ponds, irrigated rice fields supply water that remains uncontaminated as if flows through the aquifer. These results have changed the way many think about contamination of groundwater in Southeast Asia, challenging the view held by many researchers that groundwater chemistry is largely a function of local mineral content in the aquifer. Her work has also lead to new ideas for providing safe water, such as installing shallow wells beneath rice fields where groundwater appears to be safe. Indeed, her work, showing the relation of land-use to groundwater quality, has important implications for agriculture and water management throughout the world.
