pH-Sensitive mutagenic activity of ozone-treated 1,2-dimethylhydrazine in the Salmonella/microsome assay

Treatment with ozone inactivates the mutagenicity of many carcinogens in aqueous solution. The colon carcinogen, 1,2-dimethylhydrazine (DMH) has been reported an exception; ozone treatment convenrts dimethylhydrazine from a non-mutagen into a mutagen. In the Salmonella/microsone assay, the mutagenicity of ozone-treated dimethylhydrazine was dependent on pH. The ozonation product was a strong mutagen in acidic but was not mutagenic in basic solution. The mutagenicity of the acidic ozonation product was inactivated by raising the pH of the solution. Unlike untreated dimethylhydrazine, its ozonation product in basic solution was not converted to a mutagen in this ozone-low pH system.