Exposure of man to environmental PCBs--an exposure commitment assessment.

Polychlorinated biphenyls have been widely used in industry, but because of recognised environmental and human health hazards are now mostly restricted to closed electrical systems. PCBs are extremely stable compounds and are persistent in the environment once released. Representative values of PCB concentrations in the background environment and in man are selected from available data and a pathway analysis is performed utilizing the exposure commitment method. Dietary intake of PCBs is quite variable depending primarily on consumption of contaminated fish. Representative intake of 24 micrograms d -1 may be associated with concentrations in man of 0.35 mgkg -1 of body weight, from which a mean residence time in the body of 3 years may be inferred. Diminished intake and body concentrations should eventually become evident, reflecting reduced industrial usage and releases to the environment of PCBs. The exposure evaluation accounts also for secondary pathways to man from PCBs in air and drinking water. The analysis provides a framework for assessment of PCB movements through the environment in pathways to man. The estimates of transfer factors obtained from representative background levels should be generally relevant and may be applied to more specific cases of exposure.