Model of the Uptake of Pesticides by Plant

Abstract

The government agencies for pesticide registration in USA and EU are now adopting a tiered approach to evaluate pesticides. In this system, they are beginning to allocate important roles to computer simulation models as a screening tool, in order to handle the vast number of pesticides waiting to be registered or re-registered. To date, a number of plant uptake models for pesticides have been published, although no plant uptake model is in practical use in risk assessment for regulatory purpose. Recently, EU authorities reported the usage of the PlantX model developed by Trapp et al. in the European Union System for Evaluation of Substances (EUSES). With this as a foothold, it is well predicted that the increasing demand for more accurate plant uptake models will evolve in the future. The basic concept adopted in these models is the partition-based theory which expresses translocation and distribution of the pesticides via changes in the equilibrium of concentration between different phases or adjacent compartments. This review will summarize the foundation of the partition theory including fugacity as well as applications to these models.