Résumé
Modern agriculture is based on the increasing use of pesticides. Environmental contamination by pesticides as well as thehealth impacts are now proven. The transfer of these products into surface waters or groundwater could lead to exposure of thegeneral population living near agricultural areas. The study aims to provide a useful methodology to characterize the pollution riskresulting from the direct application of plant protection products and their transfer by runoff within a watershed. This methodologyis tested on two areas where intense rainfall are causing major runoff, one in Languedoc-Roussillon ( France) and the other in theextreme north of Cameroon. The first step is to quantify the pest pressure within the municipalities in the studied areas with theTreatment Frequency Index (IFT). Then in a second time a hydrological analysis, based on the adaptation of the cartographicmethod IRIP (Indicator of the flood hazard by Intense Pluvial runoff), allows a characterization of areas suitable for the productionor accumulation of runoff. Finally, the use of a Geographic Information System (GIS) allows, by matching the IFT and the streamingareas to define different levels of pollution hazard within the watershed. This study should refine the definition of human exposure inepidemiological analyzes in the general population. However, the lack of consideration of the air and underground propagationof these products is one of its major limitations. Finally, it could be supplemented by the inclusion of underground water transfers tobetter assess the pollution in the river system.