Consideration of the possible carcinogenicity of some pesticides.

The sophistication, sensitivity, and the predictability of carcinogenesis bioassays using small rodents is reviewed. Bioassays were conducted using both sexes of mice (B6C3F1:C57BL/6xC3H F1 hybrid) and rats (Osborne-Mendel or Fisher 344). Chemicals tested included three acaracides, two fungicides, two fumigants, four herbicides, twelve chlorinated insecticides, and five organo-phosphorus insecticides. The tumor response of each test strain and sex to the above chemicals is discussed, as well as the spontaneous tumor incidence of each strain. The results suggest caution when interpreting the data from bioassays.