ABSTRACT
This chapter describes concepts, uses, and limitations of state-of-the-art mathematical environmental pollutant fate modeling for use in hydrocarbon fate studies and analyses of environmental quality. Models are available for organic dissolved compounds, immiscible fluids, and inorganic compounds. Major transport and transformation processes for organic dissolved contaminants are advection, dispersion, sorption and retardation, and chemical and biological transformation. Physical processes affecting dissolved organic compound fate in soil systems are mainly: advection, dispersion, volatilization; and sorption, ion-cation exchange. Chemical processes affecting dissolved contaminant migration are mainly ionization, hydrolysis, oxidation/reduction, and complexation. Biological processes affecting dissolved contaminant migration are mainly bioaccumulation and biodegradation. Model selection, application, and validation are issues of major concern in mathematical soil and groundwater dissolved pollutant modeling. Important interactions of dissolved aqueous inorganic species occur with soils. In general, soil/ground water modeling concepts deal mainly with point source pollution and can be categorized into unsaturated soil zone, saturated soil zone, geochemical, and ranking.
