Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions
Article first published online: 7 APR 2006
Copyright 2006 by the American Geophysical Union.
Water Resources Research
Volume 42, Issue 4, April 2006
How to Cite
2006), Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions, Water Resour. Res., 42, W04404, doi:10.1029/2005WR003979., , and (
- Issue published online: 7 APR 2006
- Article first published online: 7 APR 2006
- Manuscript Accepted: 3 JAN 2006
- Manuscript Revised: 19 NOV 2005
- Manuscript Received: 21 JAN 2005
- reactive transport;
- solute transport;
 The reactive transport of U(VI) in a shallow alluvial aquifer beneath a former U(VI) mill located near Naturita, CO, was simulated using a surface complexation model (SCM) to describe U(VI) adsorption. The groundwater had variable U(VI) concentrations (0.01–20 μM), variable alkalinity (2.5–18 meq/L), and a nearly constant pH equal to 7.1. U(VI) KD values decreased with increasing U(VI) and alkalinity, and these parameters were more important than sediment variability in controlling KD values. Reactive transport simulations were fit to the observed U(VI) and alkalinity by varying the concentration of U(VI) and alkalinity in recharge at the source area. Simulated KD values varied temporally and spatially because of the differential transport of U(VI) and alkalinity and the nonlinearity of U(VI) adsorption. The model also simulated the observed U(VI) tailing, which would not be expected from a constant KD model. The simulated U(VI) concentrations were sensitive to the recharge flux because of the increased flux of U(VI) to the aquifer. The geochemical behavior of U(VI) was most sensitive to the alkalinity and was relatively insensitive to pH.