Mutation analyses of a series of TNT-related compounds using the CHO-hprt assay

Trinitrotoluene (TNT) and related compounds were tested for induction of mutation in the CHO-hprt mutation assay. The parent compound, TNT, was consistently found to be mutagenic at concentrations above 40 microg ml(-1), whether or not S9 activating enzymes were added. Five TNT metabolites gave statistically significant but small increases in mutation frequency over solvent controls: 4-amino-2,6 dinitrotoluene, 2,4',6,6'-tetranitro-2',4-azoxytoluene, 2,2',6,6'-tetranitro-4,4'-azoxytoluene, 2',4,6,6'-tetranitro-2,4'-azoxytoluene and triaminotoluene. Clear dose-response relationships could not be established for the mutagenic response of these compounds. They are considered as very weak mutagens in this mammalian test system. Five compounds did not produce statistically significant mutation frequencies at the levels tested: 2-amino-4,6-dinitrotoluene, 2,4-diamino-6-nitrotoluene, 1,3,5-trinitrobenzene, 2,6-diamino-4-nitrotoluene and 4,4',6,6'-tetranitro-2,2'-azoxytoluene. The results indicate that none of the TNT metabolites tested pose a significant mutational health risk, at least as judged by the CHO-hprt assay.