Many drugs used in human medicine are detectable in surface waters from the low to the very low microgram/L concentration range. In drinking waters only some of these substances were detected, the concentrations are usually an order of magnitude below the concentrations found in surface waters. A risk assessment of long time effects caused by a permanent intake of these low concentrations of drug residues cannot be done at this time. Hormonally active substances in surface waters may present an ecotoxicological risk, there are many investigations currently under way to assess this problem. Our investigations show for the first time that residues of the commonly used veterinary drugs tetracycline and chlortetracycline can be detected in the surface of soil (0-40 cm) fertilized with animal slurry. The maximum concentrations found were 32.3 micrograms/kg and 26.4 micrograms/kg respectively. Leaching of these compounds into seeping water sampled at a depth of 80-140 cm could not be detected with the methods employed. The significance of the detected antibiotic residues in soil samples for the quality of food of animal origin or any ecotoxicological consequences needs further investigations. The knowledge about the concentrations of veterinary drug residues resulting from animal husbandry in the environment is the first step for such a risk assessment.