The mutagenic properties of hexachloroacetone in short-term bacterial mutagen assay systems

Hexachloroacetone, CCl3--CO--CCl3, reverts the Ames strains TA98 and TA100 but not the non-plasmid strains TA1537, TA1535 and TA1538. In the absence of solvent, the number of revertant colonies is 5 times the spontaneous reversion rate for TA100 and 10 times the spontaneous reversion rate for TA98 with 26 mg hexachloroacetone per plate. This effect is seen in the absence of rat liver microsomes. In dimethylsulfoxide (DMSO) solution a more complicated pattern is seen. In DMSO solution cooled between 18 and 20 degrees C, The maximum nuber of revertants is similar to that found in the absence of DMSO, but only 1.75 mg hexachloroacetone per plate is needed. When DMSO solution of hexachloroacetone is warmed above 20 degrees C, a yellow color develops and the solution becomes more toxic to the test bacteria. The maximum number of revertants is then produced at about 0.5 mg hexachloroacetone per plate. Hexachloroacetone is found to be active, without microsomal activation, in the E. coli WP-2 and E. coli rec-BC test systems. Hexachloroacetone readily reacts with water in DMSO solutions to form the non-mutagenic hexachloroacetone hydrate.