Modelling of contaminant migration in unsaturated soils

Abstract

Laboratory studies are useful for understanding the behaviour of chemical contaminants in soil, although such investigations do not always relate directly to field conditions. This paper reports an application of a model in order to investigate the migration of nitrates through the soil. The model calibration was carried out using the experimental data obtained from two different soil samples collected in the countryside of Catania (Italy). The device used for laboratory scale study was a permeameter loaded with the soil samples; acqueous solutions containing different percentage of nitrate were used as chemical contaminant. Two software products, SEEP/W and CTRAN/W, are used in tandem to analyze the contaminant transport for unsaturated conditions: SEEP/W computes the water flow velocity, volumetric water content, and water flux; CTRAN/W uses these parameters to compute the contaminant migration. Unsaturated zone models are useful tools in predicting the effects of measures and can be used to optimise agricultural practice aiming to minimise the impact on the environment. © 2007 WIT Press.