Environmental Risk Assessment for Veterinary Medicinal Products Part 4. Exposure assessment scenarios

Residues of veterinary medicinal products reach the environment through spreading of slurry on agricultural soil. In this report animal husbandry, slurry handling and environmental conditions throughout Europe are considered in order to define realistic worst case scenarios, in conjunction with environmental distribution models. Given the variability in manure management a straightforward approach for the manure model was selected. Realistic worst case conditions are proposed in a simple scenario assuming single treatment per place, standard European nitrogen production values, application of the a manure application rate of 170 kg N/ha/year in one time, with a manure production volume of one month containing the full residue, no dissipation during storage, and incorporation into 5 cm soil. Risk reduction measures related to manure management and manure treatment cannot be assessed using the proposed methodology. Scenarios and models for distribution to surface and groundwater provided by FOCUS are considered suitable for veterinary drugs. Additionally, for run-off and erosion in Mediterranean regions a river-catchment model is designed