ABSTRACT
In the previous chapters, various causes that give rise to differences in environmental concentrations of contaminants and their partitioning over the different phases (e.g. solid, liquid, gas, adsorbed, and dissolved phases) have been discussed. These causes include spatial and temporal variation in 1) the natural background concentration of contaminants, 2) the amounts and rates of contaminant inputs, and 3) the transport and chemical transformation processes the contaminants are subject to. The natural background concentration of chemicals in soil and the vadose zone depends on factors such as the natural composition of the parent material and the nature and intensity of soil-forming processes (see Section 1.3.2).
