The objective of this work was to evaluate the variation in the electrical conductivity and the mobilization of ions present in reject brine from desalination plant of brackish well water in three types of soil. The mobilization of the contaminant ions in the reject brine was studied in glass percolation columns, which were filled with soil of contrasting textures (eutrophic CAMBISOL, typic dystrophic Red OXISOL, ENTISOL Quartzipsamment). Experiments ware repeated three times each, and the initial and final concentrations of the ion contaminants were analyzed. The pollution potential of this residue was determined by the retardation factor and dispersion-diffusion coefficient of Ca 2+ and Mg 2+ , besides the variation of electrical conductivity along the profile of each soil studied. In the Red Oxisol, Ca 2+ and Mg 2+ ions move with greater ease resulting in possibility largest of potential of ground water contamination. In Entisol Quartzipsamment presented higher Mg 2+ (R) ion advancement speed, that is, higher subsurface contamination power for these ions. The eutrophic Cambisol presented low diffusion-dispersion coefficient in all the evaluated ions and, therefore, lower mobility of the ions in the soil profile, and consequently, a greater possibility of contamination when irrigated with reject brine.

-Percolation columns constructed in the Laboratory can predict the degree of contamination in soil due to reject brine disposal and can be a tool for reducing environmental impacts. This study aim to evaluate the mobilization of ions in reject brine from desalination process by reverse osmosis. The mobilization of the contaminant ions in the saline waste was studied in glass percolation columns, which were filled with soil of contrasting textures (eutrophic CAMBISOL, typic dystrophic Red OXISOL, ENTISOL Quartzipsamment). Experiments ware repeated three times each, and the initial and final concentrations of the ion contaminants were analyzed. The pollution potential of this wastewater was determined by the retardation factor and dispersion-diffusion coefficient of K + , Cl -and Na + for each studied soil. The differences in the displacement curves of the ions present in the saline waste among various soil types were analyzed. The Entisol Quartzipsamment showed a higher forward speed of the ions K + and Cl -(greater retardation factor, i.e., greater power of the subsurface contamination for these ions). In typic dystrophic Red OXISOL, the ions move with greater ease and therefore produced greater groundwater contamination. In eutrophic CAMBISOL, the low coefficient of diffusion-dispersion in all ions was evaluated (i.e., reduced ion mobility is directly influenced by their exchangeable levels).Keywords: Semi-arid. Water reuse. Reverse osmosis. POTENCIAL CONTAMINANTE DE ÍONS ESPECÍFICOS EM SOLOS TRATADOS COM

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