ABSTRACT
A wide diversity of physical and chemical processes control the distribution of species in waters in the vadose zone above the water table, and in the saturated zone below. The mineralogical composition of rocks or sediments, chemical reactions between solid, aqueous and gas phases, and oxidation/reduction (redox) processes are principal factors that influence the chemical composition of vadose-zone, ground-and surface waters, and the concentrations and mobilities of individual species.
