Mine Water and the Environment

, Volume 28, Issue 2, pp 84–93

Comparing Approaches for Simulating the Reactive Transport of U(VI) in Ground Water


    • US Geological Survey
  • Matthias Kohler
    • Department of Civil and Environmental EngineeringUniversity of Maine
  • James A. Davis
    • US Geological Survey
Technical Article

DOI: 10.1007/s10230-009-0064-x

Cite this article as:
Curtis, G.P., Kohler, M. & Davis, J.A. Mine Water Environ (2009) 28: 84. doi:10.1007/s10230-009-0064-x


The reactive transport of U(VI) in a well-characterized shallow alluvial aquifer at a former U(VI) mill located near Naturita, CO, was predicted for comparative purposes using a surface complexation model (SCM) and a constant Kd approach to simulate U(VI) adsorption. The ground water at the site had U(VI) concentrations that ranged from 0.01 to 20 µM, alkalinities that ranged from 2.5 to 18 meq/L, and a nearly constant pH of 7.1. The SCM used to simulate U(VI) adsorption was previously determined independently using laboratory batch adsorption experiments. Simulations obtained using the SCM approach were compared with simulations that used a constant Kd approach to simulate adsorption using previously determined site-specific Kd values. In both cases, the ground water flow and transport models used a conceptual model that was previously calibrated to a chloride plume present at the site. Simulations with the SCM approach demonstrated that the retardation factor varied temporally and spatially because of the differential transport of alkalinity and dissolved U(VI) and the nonlinearity of the U(VI) adsorption. The SCM model also simulated a prolonged slow decline in U(VI) concentration, which was not simulated using a constant Kd model. Simulations using the SCM approach and the constant Kd approach were similar after 20 years of transport but diverged significantly after 60 years. The simulations demonstrate the need for site-specific geochemical information on U(VI) adsorption to produce credible simulations of future transport.


Reactive transportUraniumEnvironmental geochemistryGeochemical modeling

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© Springer-Verlag 2009