[Exposure to residues on plant surfaces following the use of organophosphate insecticides in agricultural apple orchards].

Pesticides based on dimethoate, methamidophos and parathionmethyl are largely used in apple growing centres from the end of May to July. Initial residue concentrations (0.39, 1.4 and 0.4 micrograms.cm-2, respectively) and the degradation of these residues are described together with the relevant half-life periods. They are related to safety margins for residues on leaf surfaces to standardise dermal exposition, respective reentry times being discussed. On the basis of the concentration of active ingredients in the air and of residues on leaf surfaces it is estimated that dermal exposition is predominant on harvest and cultivation in treated apple orchards.