Existing concentrations of radionuclides and arsenic in a uranium tailings pond and groundwater, and hydrogeologic and mass transport parameters were utilized in a Galerkin-based finite element mass transport model to predict future migration potential for discrete chemical species. Field and laboratory data and the results of computer modeling indicate that movement of chemical species of interest at the subject site is mitigated by chemical reaction with in situ soils including precipitation, coprecipitation, and ion exchange. The study showed that among the hydrogeologic and mass transport parameters, distribution coefficients are the major controlling factor in determining the extent of attenuation of radionuclides and arsenic. These coefficients are specific to individual chemical species and are highly dependent on groundwater pH conditions and particular soil characteristics.