Abstract
Environmental risks from plant protection products (PPPs) need to be assessed to ensure safe use. The risk assessments are generally carried out using the common vole as a focal species with conservative theoretical estimates of external exposure. These are then compared to dose-related toxicity endpoints established in toxicity studies, often with laboratory species. The aim of the present study was to determine the actual internal dosimetry of PPPs' active ingredients (AIs) in a population of common voles to provide the basis for informed higher tier risk assessment. As a proof of concept, two fungicidal AIs (fludioxonil and cyprodinil) were investigated using a range of application methodologies. Individuals were treated using oral gavage application (AI dose: 100/200 mg/kg) and fed treated grass (AI sprayed at 2 kg/ha) under laboratory, semi-natural, and natural conditions. Our results show that demographic factors play a significant role in the individual residue profile and that age structure is a key aspect that determines the overall exposure risk of a population. These results are consistent from laboratory to field conditions. Future approaches could establish dose-residue relationships that are reflective of natural food intake rates in wild common vole populations in the risk assessment of PPPs.