Numerical inverstigations of the transport behavior of U(+6) in groundwater
Uranium is a main contaminant in groundwater of a number of US Department of Energy (DOE) sites what were used for the processing of uranium and other radio nuclides. Under oxic and sub-oxic redox conditions uranium is predominantly present as soluble and thus mobile species in the redox state +6. However, its mobility is strongly controlled by adsorption to mineral surfaces. Besides the reactive surface area of the aquifer material, the adsorption strength depends mainly on the prevailing groundwater composition, especially pH, alkalinity and calcium concentration. Investigations carried out in the Integrated Field-Scale Subsurface Research Challenge (IFRC) project of the DOE are focused on the transport behavior of uranium(VI) under complex hydrological and hydrogeochemical conditions at the field scale. Intensive field, laboratory and numerical studies are carried out for the contaminated DOE sites Hanford 300A, Washington and Old Rifle, Colorado. The aims are (i) to identify and quantity the principal processes that control the field scale behavior of uranium(VI) and (ii) to predict the natural attenuation potential of the studied sites and the efficiency of potential remediation schemes.
The activities of the working group Hydrogeology and Landscape Hydrology at the University of Oldenburg focus on numerical studies and scenario modeling. They are a continuation of the numerical studies on reactive transport of uranium(VI) at the Hanford 300A site that were carried out at CSIRO Land and Water, Australia.
CSIRO Land and Water, Australia; University of Alabama, USA; China University of Geosciences, China; Pacific North West National Laboratory, USA, Lawrence Berkeley National Laboratory, USA
Greskowiak, J., Hay, M. B., Prommer, H., Liu, C., Post, V.E.A., Ma, R., Davis, J. A., Zheng, C., Zachara, J. M. (2011). Simulating adsorption of U(VI) under transient groundwater flow and hydrochemistry - Physical versus chemical non-equilibrium model, Water Resour. Res., 47, W08501, doi:10.1029/2010WR010118
Yin, J., R. Haggerty, D. L. Stoliker, D. B. Kent, J. D. Istok, J. Greskowiak, and J. M. Zachara (2011). Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments, Water Resour. Res., 46, W09509, doi:10.1029/2009WR008781
Greskowiak, J., Prommer, H., Liu, C., Post, V.E.A., Ma, R., Zheng, C., Zachara, J. M. (2010), Comparison of parameter sensitivities between a laboratory and field scale model of uranium transport in a dual domain, distributed-rate reactive system, Water Resour. Res., W09509, doi:10.1029/2009WR008781
Ma, R., Zheng C., Prommer, H.,Greskowiak, J., Liu, C., Zachara, J. M., and Rockhold, M. L. (2010). A Field-Scale Reactive Transport Model for U(VI) Migration Influenced by Coupled Multi-Rate Mass Transfer and Surface Complexation Reactions, Water Resour. Res., 46, W05509, doi:10.1029/2009WR008168
Ma, R., Zheng, C., Liu, C., Greskowiak, J., Prommer, H., Zachara, J. (2014): Influence of calcite on uranium(VI) reactive transport in the groundwater-river mixing zone, Water Resour. Res., doi: 10.1002/2013WR013835
Ma, R., Liu, C., Greskowiak, J., Prommer, H., Zachara, J., Zheng, C. (2014): Influence of calcite on uranium(VI) reactive transport in the groundwater-river mixing zone, J. Cont. Hydrol.,156, 27-37