ABSTRACT
Environmental transport and dispersion modeling is a highly developed field of study; in fact, it is several highly developed fields of study, since transport in each of the different environmental media is the realm of a different discipline. A difficulty for exposure assessment is that environmental transport models have not, in general, been developed to estimate human exposure, but to estimate environmental concentrations at some distance from the source, often for regulatory analysis. Preliminary exposure assessments for hazard assessments or preliminary risk assessments may focus on the single largest or most probable route of exposure. The sophistication of the dose-response model clearly should be considered in selecting the exposure models. Principal exposure pathways usually require concentrations to be determined at water supply intakes, points of irrigation water withdrawal, and at bathing beaches.
