Sustaining Irrigation Supplies through Immobilization of Groundwater Arsenic In Situ

Geogenic arsenic (As) in groundwater is widespread, affecting drinking water and irrigation supplies globally, with food security and safety concerns on the rise. Here, we present push-pull tests that demonstrate field-scale As immobilization through the injection of small amounts of ferrous iron (Fe) and nitrate, two readily available agricultural fertilizers. Such injections into an aquifer with As-rich (200 ± 52 μg/L) reducing groundwater led to the formation of a regenerable As reactive filter in situ, producing 15 m