Determining the Elemental Composition of Naturally Reduced Sediments at Old Rifle Aquifers

• Large uranium plumes still persist in groundwater at legacy Department of Energy (DOE) due to past uranium extraction and processing. • At Old Rifle, >34 million gallons of groundwater is contaminated with uranium. •Naturally reduced zones (NRZ) are areas in the aquifer that contains highly reduced content. •The mobility of uranium depends on its valence state: oxidized U(VI) is highly soluble and reduced U(IV) precipitates easily.