Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments
Article first published online: 5 APR 2011
Copyright 2011 by the American Geophysical Union.
Water Resources Research
Volume 47, Issue 4, April 2011
How to Cite
2011), Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments, Water Resour. Res., 47, W04502, doi:10.1029/2010WR009369., , , , , , and (
- Issue published online: 5 APR 2011
- Article first published online: 5 APR 2011
- Manuscript Accepted: 18 JAN 2011
- Manuscript Revised: 2 DEC 2010
- Manuscript Received: 27 MAR 2010
- groundwater–surface water interaction;
- multirate mass transfer
 In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry.