ABSTRACT
Contaminants are “unnatural” substances introduced in the subsurface that degrade natural or existing groundwater quality. When a contaminant is introduced at the ground surface, it must migrate through the unsaturated zone toward the aquifer. Hence, contaminants will move through soil, sediment, fractured rock, man-made conduits, or other pathways on their way to the saturated zone. Obviously a complete list of contaminants is beyond this discussion; however, the following list of contaminant groups is presented. Solubility is the degree and ease to which the chemical or compound will dissolve in water. Solubility determines the concentration present in water and if the contaminant will interact with other chemicals and to the extent that they become molecularly or ionically dispersed in the solvent to form a true solution. Vapor pressure can be considered related to the solubility of the compound in air from the liquid phase.
