The input of anthropogenic trace substances into the environment, such as human and veterinary pharmaceutical residues or industrial chemicals, has increasingly become the focus of scientific and social attention in recent years. Modern analytical methods allow the detection of these anthropogenic contaminants even in low concentration ranges, and thus numerous drug findings in the various environmental compartments are reported in the literature. Various studies in recent years have also demonstrated a number of negative effects of these substances on humans, animals and the environment. One of the main sources of residues of veterinary medicinal products in the (aquatic) environment is the application of fertilisers to agricultural land. Within the framework of the planned research project, this input path will be investigated and quantitatively evaluated by means of laboratory and field experiments on different scales. The aim is to generate a new understanding of the processes involved in the degradation and transport behaviour of veterinary pharmaceuticals in the environmental compartments of groundwater and soil, and to transfer this understanding to practical application, for example by means of a concept for the sustainable use of agricultural fertilisers. With regard to the protection of water resources, the environmental relevance of frequently used veterinary medicinal products will be assessed and key parameters that significantly influence the behaviour of these substances will be identified.