A unified approach to exposure assessment by computer models for degradation reactions and soil accumulation: The triazine herbicide example

A comprehensive approach to exposure assessment of chemicals must include metabolites of the initial compounds. We present here an approach that combines a knowledge-based system for the prediction of degradation pathways with an analytical soil transport model. The performance of this combination of systems is illustrated with an analysis of seven s-triazine herbicides and their 35 degradation products. In a ranking procedure using the Hasse diagram technique, the relationships between chemical structure and the hazard potential in a loam soil scenario is analyzed. Sequences of chemical structures with comparable and non-comparable hazard potentials are identified.