The Joint FAO/WHO Expert Committee on Food Additives (JECFA) recently attempted
to evaluate PCBs (FAO/WHO 1990). The Committee concluded that, due to the
limitations of the available data, it was impossible to establish a precise numerical value
for a tolerable intake for humans. However, it was concluded that the monkey was the
most appropriate animal for use in studies with PCBs and that 0.04 mg/kg b.w./day was a
no effect level in the monkey studies considered. It was also noted that some PCB
mixtures were hepatocarcinogenic in rodent bioassays, but that available studies in
humans were inconclusive with respect to an association between exposure to PCB and
increased mortality due to cancer.