High‐Arsenic Groundwater in the Southwestern Bengal Basin Caused by a Lithologically Controlled Deep Flow System

Elevated arsenic in Bengal Basin aquifers threatens human health. Most deep (>150 m) groundwater in Pleistocene aquifers is low in arsenic; however higher concentrations have been reported in the southwest border region. Here, we establish that this extensive arsenic contamination at depth is not associated with well failure. A combination of geochemistry and flow modeling constrains the factors that contribute to arsenic contamination at...