Arsenic is an emerging water quality issue in Iowa’s groundwater. According to the Iowa Department of Natural Resources, there are 69 public water supplies that utilize groundwater with arsenic concentrations greater than the recommended limit and in as recent survey of 473 private wells in Iowa, 48% were found to contain arsenic. This study will help address the issue of arsenic in groundwater by conducting laboratory experiments to better understand the geochemical processes controlling the release of arsenic from soils to groundwater. This project will build on previous work that developed analytical methods for measuring arsenic and investigating the reduction of arsenic by common soil minerals. The objectives of this study are to 1) determine the extent of arsenic incorporation and release from iron minerals commonly found in Iowa aquifers, and 2) measure the release of iron and arsenic from Iowa aquifer materials where arsenic has been identified in the groundwater.