|
Read Full Article (file size: 966214 bytes) Cited by
WATER RESOURCES RESEARCH,
VOL. 42,
W04404,
doi:10.1029/2005WR003979,
2006
Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions
Gary P. Curtis
U.S. Geological Survey, Menlo Park, California, USA
James A. Davis
U.S. Geological Survey, Menlo Park, California, USA
David L. Naftz
U.S. Geological Survey, West Valley City, Utah, USA
Abstract
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.
Received 21
January
2005;
accepted 3
January
2006;
published 7
April
2006.
Keywords: adsorption;
reactive transport;
solute transport;
uranium.
Index Terms: 1009 Geochemistry: Geochemical modeling (3610, 8410); 1803 Hydrology: Anthropogenic effects (4802, 4902); 1831 Hydrology: Groundwater quality; 1832 Hydrology: Groundwater transport.
Read Full Article (file size: 966214 bytes) Cited by
Citation: Curtis, G. P., J. A. Davis, and D. L. Naftz
(2006),
Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions,
Water Resour. Res.,
42,
W04404,
doi:10.1029/2005WR003979.
This paper is not subject to U.S. copyright. Published in 2006 by the
American Geophysical Union.
|