A software package that includes two major computational modules (PRZM and VADOFT) for generating a deterministic simulation of the fate of agricultural pesticides. Taking management practices into account, PRZM-2 simulates the transport and transformation of field-applied pesticides in the crop-root zone and the underlying unsaturated zone. By accounting for the variability in natural systems as well as uncertainties in system properties and processes, the program provides probabilistic estimates of exposure concentrations. The program can model multiple pesticides or parent/daughter relationships. Concentration estimates can be generated for various media for use in exposure assessments.