Hydrogeochemical simulation and experimental determination of Zn transport in sediments at Mar del Plata, Argentina.

MASCIOLI S. AND MARTÍNEZ D.E.

Groundwater and human development

Balkema

Lugar: Leiden, The Netherlands; Año: 2005; p. 207 - 216

Abstract. Infiltration experiments of undisturbed sediments in columns have been performed with the goal of calibrating a 1D reactive transport model to be applied to Zn2+ mobility. The essays were carried out on sediments from A hilly region to the north of Mar del Plata City, Argentina. The sediments were carefully taken, driving the columns into the soil in order to minimize possible disturbances. The adjustment of the experimental breakthrough curves for chloride essays to the curves obtained using the code Phreeqc 2.0 for transport modeling were used to calibrate the model parameters. The obtained values were 0.01 m and 0.35 for dispersivity and porosity, respectively. A volume of a ZnCl2 solution equivalent to six times the pore volume of the column was passed through the columns, measuring Zn2+ concentration after each 0.5 pore volume arrival. To achieve a satisfactory agreement between the observed and simulated Zn2+ curves it was necessary to consider the adsorption in exchange surfaces and the equilibrium with the solid phase Zn(OH)2 in the numerical model. The results obtained show that at the end of the experiment the main proportion of Zn2+ is adsorbed, remaining in the first 5 cm of the columns.Infiltration experiments of undisturbed sediments in columns have been performed with the goal of calibrating a 1D reactive transport model to be applied to Zn2+ mobility. The essays were carried out on sediments from A hilly region to the north of Mar del Plata City, Argentina. The sediments were carefully taken, driving the columns into the soil in order to minimize possible disturbances. The adjustment of the experimental breakthrough curves for chloride essays to the curves obtained using the code Phreeqc 2.0 for transport modeling were used to calibrate the model parameters. The obtained values were 0.01 m and 0.35 for dispersivity and porosity, respectively. A volume of a ZnCl2 solution equivalent to six times the pore volume of the column was passed through the columns, measuring Zn2+ concentration after each 0.5 pore volume arrival. To achieve a satisfactory agreement between the observed and simulated Zn2+ curves it was necessary to consider the adsorption in exchange surfaces and the equilibrium with the solid phase Zn(OH)2 in the numerical model. The results obtained show that at the end of the experiment the main proportion of Zn2+ is adsorbed, remaining in the first 5 cm of the columns.