Geochemical transformations beneath man-made ponds: Implications for arsenic mobilization in South Asian aquifers.

ABSTRACT: The role of man-made ponds on arsenic mobilization was examined in Bangladesh. Here, we describe a field experiment that shows how recharge from a newly constructed pond creates a reactive front that moves downward into the underlying aquifer, but only advances slowly, less than 8 cm/year. We found that pond recharge introduces organic carbon that likely drives the reduction of sulfate and solid-phase iron. However, over the six-year period of the study the pond did not drive arsenic contamination of the underlying groundwater. An electron balance indicates that significant precipitation of ferrous iron and sulfide minerals may immobilize arsenic despite the shift towards more reducing conditions, explaining the very low observed aqueous arsenic concentrations. We additionally found that t

SUBMITTER: Stahl MO 

PROVIDER: S-EPMC9435115 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature