U.S. Department of Energy


Date of this Version



Environ. Sci, Technol. 1993, 27, 1937-1939


The fate of radionuclides in the subsurface is of critical importance to the planning, siting, and evaluation of repositories for radioactive wastes. Mathematical models are an integral component of this process. An accurate understanding of radionuclide transport is required to successfully formulate and use these models. It is well-known that the subsurface is both physically and chemically heterogeneous. Recent research has shown that the resultant spatial variability of hydraulic conductivity and of sorption capacity can significantly affect solute transport in the subsurface. The impact of hydraulic conductivity variability and sorption capacity variability on the transport of radionuclides is, therefore, of great interest. Very few well-controlled, experimentally based laboratory investigations of the transport of radionuclides in physically and chemically heterogeneous porous media have been reported in the literature. The purpose of this paper is to report the preliminary results of such an investigation. We present results obtained for transport of Co2+ in a column packed with two media of differing hydraulic conductivities and sorption capacities. In addition to being influenced by these heterogeneities, transport of the Co2+ is also influenced by rate-limited diffusive mass transfer and non-equilibrium sorption.