Simultaneous heat, moisture and DNAPL transport due to diurnal soil-atmosphere interaction in four different unsaturated land elements is investigated by one-dimensional numerical simulation. SALSA coupled with DNAPL transport equations predicts its migration in subsoil from the initially top contaminated layer. The results indicated the significance of vegetation cover and other soil properties on soil heat and moisture budgets and hence DNAPL volatilization and migration to higher soil depth. Forest and porous pavement elements respectively showed the minimum and maximum fluctuations in soil temperatures and water contents. DNAPL in aqueous phase penetrated to relatively deeper soils in forest element. This penetration depth decreased for short grass, bare soil and porous pavement elements respectively. The gas phase transport into the lower soil is comparatively smaller. However, the tendency of downward transport is similar to that in liquid phase.
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