Synergistic, additive, and antagonistic mutagenic responses to binary mixtures of benzo(a)pyrene and benzo(e)pyrene as detected by strains TA98 and TA100 in the Salmonella/microsome assay.

Binary mixtures of benzo(a)pyrene (B(a)P) and benzo(e)pyrene (B(e)P) produce synergistic mutagenic (comutagenic) responses in Salmonella typhimurium strain TA98 (a frameshift detector). The optimum enhancement (25 X) was found at B(a)P concentration of 0.3 microgram/plate and B(e)P concentration of 1.5 microgram/plate. The response of strain TA100 (mostly a base-substitution detector) is opposite that of TA98, showing antagonism and additivity in similar concentration ranges.