The Evaluation of Genotoxicity Using DNA Repairing Test for Chemicals Produced in Chlorination and Ozonation Processes

The umu-test which can detect the induction of DNA repair is applied in order to analyze the genotoxicity of by-products of chlorination and ozonation. In this research work, the genotoxicities of 37 comnercial chemicals which are expected to be involved in the by-products of chlorination and ozonation processes are checked and evaluated by the umu-test. The genotoxicities of the following organic halogenated compounds are clearly detected: Without microsomal activation; m-dichlorobenzene, 1,2,4-trichlorobenzene and bromoform: With microsomal activation; m-dichlorobenzene, dichloroacetic acid, trichloroacetic acid and chloral are detected. From the results on some compounds which are expected to be produced by ozonation, formaldehyde and ionone show positive genotoxicities without microsomal activation, and 5 compounds have positive genotoxicities with microsomal activation; formaldehyde, furfrol, carvone, glyoxal and acrolein. The effects of the concentration on genotoxicities of those chemicals are discussed and compared with the results obtained in other bacterial assays. Some of the selected organic compounds, chloroform and so on, are identified positive genotoxic, which were reported not to be mutagenic in other bacterial assays. As the Quantitative evaluation for genotoxicity on chemical dose, the time of DNA repairing on damaged spots by SOS genes and the induction rate of umu gene are experimentally evaluated.