The effects of the cationic competition on the retarding factor (fr) and the dispersion-diffusion coefficient (D) were evaluated with conducting metal mobility trials in leaching columns submitted to a saturated and steady flow. Solutions of zinc (700 mg L-1), copper (200 mg L-1) and zinc plus copper in the same concentrations, were used to obtain elution curves. Soil materials from the A, B and C horizons of Oxisol (LVa) and of Ultisol (PVc), collected in Viçosa, MG, were used. In all soil materials used, copper presented higher retarding factor values than zinc, which indicates a higher copper-soil interaction. The low velocities of the solutions resulted in low dispersion-diffusion coefficient values. Cationic competition decreased the soil retention capacity for the cations.
heavy metals; miscible displacement; pollutant dispersion
