Reactive Transport Modeling of Arsenic Mobilization in Groundwater of the Red River Floodplain, Vietnam

Abstract

The arsenic content in groundwater of the Red River floodplain decreases with the burial age of the aquifer sediment over a 6000 year period. This decrease is caused by diminishing reactivities of both sedimentary organic carbon, Fe-oxides as well as CaCO₃. Here we present a 1-D reactive transport model developed in PHREEQC-3 that quantifies the resulting changes in groundwater bulk chemistry as well as arsenic content over the last six millennia.