Abstract
'Dioxins' is the generic term given to polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar-PCB. Dioxins are produced during various combustion processes and also unwanted by-products of the manufacture of certain chlorinated compounds. As a result, dioxins are ubiquitous environmental contaminants and are generally present in very low concentrations in all foods including cows' milk and beef. It is currently considered that food is the primary source of human exposure to dioxins. The pathways of entry into food chains include the atomospheric transport of emissions and their subsequent deposition on plants, soil, and water. The major food sources seem to be fat-containing animal products in Europe and America, and seafoods in Japan, where animal products are the second important source. Dioxin concentration in retail cow's milk in Japan seems to be as same as that in England. Generally, dioxins and other lipophilic compounds are not little absorbed and translocated by plants, so residues in foods and feeds derived from seeds should be negligible. Animals that ingest high-roughage diets are the most likely to accumulate dioxins from the environment. Still, however, there are many unclear points on dioxins. So, the conclusion that forage is a maior source of animal exposure to dioxins requires verification by appropriate forage sampling and field investigation. We must appeal to society for reductions in the gross discharge of dioxins, while at the same time attempt our own technological innovation.
