ABSTRACT
Industrial waste discharges to the environment are universally associated with degradation of water quality and risk to human and ecological health. Many chemicals in industrial effl uents do not persist because of physical removal, chemical reaction, or biodegradation to less harmful by-products. The factors that differentiate compounds that are recalcitrant and compounds that are assimilated into environmental systems without appreciable consequences are called contaminant fate and transport properties. Fate and transport properties describe the propensity for a chemical to volatilize, photo-oxidize, adsorb, hydrolyze, or biodegrade and, if the chemical survives these fates, how it may advect, diffuse, or otherwise migrate through soil, groundwater, surface water, and air. These processes not only eliminate some compounds and retard the movement of others, but also affect the phase in which the chemical is present (gas, liquid, or solid). Some compounds are relatively immune to degradation and will persist in the environment for long periods of time. If released in suffi cient mass, those contaminants that are persistent, mobile, and also toxic constitute the greatest potential threat to drinking water resources.
