Pesticide risk indicators for surface water and their validation: Example of the I-PHY indicator

Abstract

The implementation of solutions to the problem of non-point source pollution due to pesticides requires the development of assessment tools of the risk associated to the application of those products. If pesticides risks indicators are currently recognised for the environmental assessment of farmers'practices, numerous studies during the last decade did not enable to conclude about their validity. The article aims at presenting results of an experimental validation of the surface water component of the I-Phy indicator from measurements of pesticide concentration in water. After a brief review of different types of indicators, we present the surface water component of the I-Phy indicator which was developed at INRA Colmar in the frame of the INDIGO® method. The construction is based on decision rules using fuzzy logic. In the surface water component, variable describing fields conditions, sensitivity to runoff and drift play a major role. In a second part, we present and discuss results of experimental validation using dataset of concentration measurement of active ingredient from three locations (Rouffach, Le Ruiné, Baslieux-sous-Châtillon). They yield a medium quality of prediction which can be partially explained by the upscaling of the indicator to watershed level.