High sensitivity of Salmonella TA102 in detecting hexavalent chromium mutagenicity and its reversal by liver and lung preparations.

The recently developed strain TA102, particularly suited to the detection of oxidative mutagens (Levin et al., 1983), was the most sensitive out of 9 strains of S. typhimurium his- in revealing the mutagenicity of Cr(VI) compounds (sodium dichromate, calcium chromate and chromium trioxide). The rank of sensitivity was the following: TA102, TA100, TA97, TA92, TA1978, TA98, TA1538 and TA1537, TA1535 being the only insensitive strain. Cr(III) compounds (chromic acetate, chromic nitrate and chromic potassium sulfate) were totally inactive with all strains. The direct mutagenicity of Cr(VI) was markedly decreased, through NADPH-requiring mechanisms, by rat-liver S9 fractions and, to a lower extent, by human lung S12 fractions, which supports the hypothesis of a metabolically regulated threshold in chromium pulmonary carcinogenicity.