Movement of metal contaminants in ground water in the Pinal Creek Basin, Arizona: model assessment and simulation of reactive transport
PublisherThe University of Arizona.
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AbstractCopper-mining activities in the Pinal Creek basin have generated a plume of acidic ground water in the regional aquifer in Pinal Creek basin. From 1984 to 1994, contaminant concentrations decreased in response to contaminant source removal, remedial pumping, and uncontaminated recharge. Two multi-species reactive transport models, PHREEQC and HYDROGEOCHEM, were assessed to determine which would best aid in analysis of physical and chemical processes that control contaminant concentrations. Only PHREEQC successfully simulated transport accompanied by oxidation-reduction reactions. Reactive transport was simulated with a one-dimensional PHREEQC mixing-cell model that accounted for advection, dispersion, precipitation, dissolution, diffuse double layer adsorption, and the oxidation and reduction of iron and manganese, respectively. Simulated and measured chemistry differed in part because ground water was at times undersaturated or supersaturated with respect to gypsum. Oxidation-reduction reactions may be slow relative to advection and the water may not be in equilibrium with redox minerals.
Degree ProgramGraduate College
Hydrology and Water Resources