Abstract The regulatory risk assessment for pesticides in the European Union follows guidance provided by the European Food Safety Authority (EFSA). They recently updated their guidance on the risk assessment for birds and mammals (B&M), which now includes a new scenario for medium herbivorous mammals feeding on cereals at BBCH stages 30–39. A key input in the exposure assessment is the residue unit dose (RUD), the residue concentration on food items for B&M to be expected after spray application of 1 kg/ha of a substance in a crop. These RUD values depend on the size and morphology of a food item, and usually the RUD is lower, the larger the sprayed plant is. Residue trials evaluated for RUDs in EFSA 2009 excluded cereals at BBCH stages ≥30 because larger cereal plants were not supposed to be preferred as food item by the small and medium sized mammals for which the regulatory risk assessment is performed. A geomean RUD of 47.2 mg/kg for monocotyledonous plants is now established by EFSA (2023) based on 218 data points, and shall be used also for herbivorous mammals eating cereal plants during BBCH 30–39. However, only 22 of these 218 data points come from trials with application in cereals at these BBCH stages. In the present evaluation, we collected residues values from 692 trials, conducted with 47 active substances, in cereals at BBCH stage 30–39, to provide a more robust database. We found an overall geomean RUD of 24.59 mg/kg for cereals at BBCH stages 30–39 and propose to merge our dataset with the 22 residue values from Annex C of EFSA (2023) in order to derive a robust default RUD value for cereals at BBCH 30–39 which can be used for risk assessment purposes. The resulting combined overall geomean RUD value is 25.05 mg/kg.
Ebeling et al. (Fri,) studied this question.