Three Methods to Assess Levels of Farmers’ Exposure to Pesticides in the Urban and Peri-urban Areas of Northern Benin

Small farmers in urban and peri-urban areas of Northern Benin use pesticides without respect of hygiene rules and any personal protective equipment (PPE). Based on observation of the local practices in Djougou, Gogounou and Parakou,field trials have been carried out under similar conditions to evaluate contamination and exposure levels of farmers, using three usual sampling methods (Visual Method, Patch Method and Whole Body Method). Both Visual and Patch Methods used dye and ghost ink as tracers. In the Whole Body trials, deltamethrin (PLAN D 25 EC) was used as insecticide treatment. Deposits were observed on the protective equipment and on the collectors. Tartrazine was determined by colorimetry and deltamethrin by gas chromatography with ECD detector (GC-ECD). The examination of protective equipment (Visual Method) showed that the whole body could be potentially exposed to pesticides. Hands were contaminated during the preparation and the loading of mixture up to sprayer rinsing. The Patch Method was not perfectly able to predict the contamination pattern on the farmers’ body. The Whole Body Method results appeared to be more variable and influenced by the skill of each operator compared to the Patch Method. The contamination levels observed were rather higher than the value estimated with a theoretical model (from 368 to 2867 mg of deltamethrin at the total/body). With PPE, the average exposure reached 3.25 mg/kg bw/day. Without PPE, the potential exposure was equal to 32.52 mg/kg bw/day. Both values far exceed the AOEL of deltamethrin (0.0075 mg/kg bw/day) indicating a high risk level for the operator. The theoretical used model (UK-POEM) was unable to predict the potential exposure outcomes measured in these trials.