AbstractA one dimensional mathematical model has been developed to predict pollutant migration in soil-leachate systems. Adsorption and Ion exchange has been modelled using the Lapidus Amundson linear steady state isotherm. The concept of dispersion as a lumped parameter has been used. The effect of biological organisms has been incorporated in a decay term. The equation and boundary conditions have been nondlmensionalised. Three nondimensional groups have been obtained. These groups relate rate of diffusion. rate of convection, rate of biological transformation and rate of chemical adsorption. Parametric studies have been done to determine the influence of these groups on the pollutant attenuation capability of the soil. Variation of concentration profiles with time have been found. Mass of pollutant diffusing and convecting into the soil layers and relative portions that are chemically adsorped and biologically transformed have been found as functions of time.Experiments have been carried out to determine the pollutant attenuation capability of the soil beneath a specific landfill. Migration patterns of eight different cations (Cu, Zn, Mn, Fe, Cr, Ca, Cd, Co) have been predicted using the mathematical model developed.Parametric studies indicate that the soli-leachate system in which a cation is least mobile corresponds to the case where the rate of convection Is more than ten times the rate of diffusion, the rste of biological transformation Is hundred times or more than the rate of convection and the concentration in the sorbed phase is hundred times more than that in the solution phase.