Quantifying Subsurface Reactive Transport of Arsenic Using a Combination of Hydrogeologic, Geochemical, and Biological Approaches

To elucidate the processes that govern arsenic cycling in aquifer systems, we have applied a combination of hydrogeologic studies of groundwater flow, geochemical investigations of the interaction between dissolved and solid components, and experimental studies of the interaction of arsenic with biota. This combined approach has been applied to quantify arsenic release and transport within a variety of systems, including soils, aquifers, streams, and the hyporheic zone. Case studies on quantifying arsenic release from minerals under abiotic and biotic conditions, arsenic adsorption to minerals, biotransformation of organoarsenic compounds, and the control of redox conditions on arsenic cycling will be presented. These studies have yielded results that can be used to calculate arsenic source terms for use in solute transport models.