Food Exposures to Polychlorinated Biphenyls

The PCB family of industrial chemicals has been used in a number of useful and beneficial ways for more than 40 years. PCBs have been used in capacitors, as transformer fluids, as heat transfer agents, in plasticizers and adhesives, and in sealants and printing inks. Needless to say, they have no place in the nation's food supply. The scientific community has been aware of the potential hazard of the PCBs since at least 1966. Reports in the foreign literature at that time indicated the detection of this chemical in fish and birds. However, the status of the analytical detection method for organochlorine pesticide residues in reference to PCBs was not perfected until early 1969, after it was discussed in FDA's pesticide analytical workshop and the former Division of Pesticides improved the analytical method, so that it was satisfactory for routine analysis. We know that as a toxic substance PCBs are a potential but not immediate health hazard and that their environmental background level is not high. We do not know how long-term exposure to PCBs might affect human health, and we cannot yet explain the inconsistent presence of the chemical in certain areas of the environment. We have been faced recently with PCB adulteration of food from accidental sources and from untraceable environmental sources. The exact routes of contamination are subject to speculation. Some theories point to the industrial wastes from plants using PCB, leaching of PCB from plastic objects in waste disposal (burning at waste incineration plants or run-off from landfills into streams), and