The concern over groundwater contamination has focused attention on the processes that influence the fate of chemicals in soil water systems. A major concern of groundwater contamination is the passage of these chemcials through the unsaturated zone and the relatively thin cover layers overlying the aquifers. Pollution due to diffuse sources is probably the most difficult to model. This is because the loads are usually non-homogeneous and they are also governed by spatially and temporally non-homogeneous, but dynamic, processes of chemical and biochemical phenomena.In this book, the...