The risk related to the presence of residues in food of animal origin has to be carefully evaluated and it is important to distinguish between the residues of veterinary drugs and environmental contaminants. The first are easily monitored and only difficultly and occasionally exceed MRL concentrations, whereas the second ones can have prolonged and high level exposures. The Safety Margins of environmental contaminants are thus lower, and the risk increases for high level consumers. It is therefore important to ovoid transfer of pollutants to food of animal origin, especially when local contamination occur.