Chemical contaminants: their metabolism and their residues

Chemical contaminants which food animals may be exposed to include agricultural chemicals (e.g. insecticides, herbicides, fungicides, fumigants), industrial chemicals, metals and natural toxins (e.g. mycotoxins, phytotoxins, bacterial toxins). In the past, most intoxications of food animals resulted from natural toxicants. However, rapid development and usage of synthetic chemicals, while greatly benefitting society, have also provided new sources of potential chemical contamination. Various sources of contamination exist, but generally at least 80% of all residues in food animals are estimated to occur through the feed. Residues from water contamination or other sources occur less frequently. This paper reviews the sources, metabolism and residue problems created by various contaminants and outlines factors and therapeutic approaches utilized in alleviating some of the common chemical residues in food animals.