First evaluation of genotoxicity of strong bases and zwitterions in treated household effluents

Various genotoxic substances in household effluents have not been sufficiently studied. The purpose of this study is to evaluate them using the umu test after dividing them based on the acid-base properties of their functional groups by solid-phase extraction cartridges. The results of the samples concentrated with reverse-phase cartridges showed that the substances with acid functional groups had stronger genotoxicity as 4.1–12.1 ng-4-NQO/mL without S9 enzyme and 17.4–51.8 ng-2-AA/mL with S9 enzyme, while the basic substances also showed a certain degree of toxicity. The results of dividing the effluents by acid-base properties using ion-exchange cartridges showed that chemical substances with strong acid functional groups did not demonstrate genotoxicity. It was found that the genotoxicity of chemicals with functional groups of weak acids was half of that of the total amount. The genotoxicity of the neutral substance was not strong, and the genotoxicity of the weak basic substances was negligible. The zwitterions and substances with strong basic functional groups showed about half the total genotoxicity. This is the first report that has investigated the genotoxicity of zwitterions in effluents. [Display omitted] •First evaluation of genotoxicity of strong bases and zwitterions in effluents.•Ion-exchange cartridge could divide the acid-base properties of genotoxicants.•Strong bases and zwitterions contributed to 46.9% of the total genotoxicity.•The contribution ratio of weak acids was 50.7% of the total genotoxicity.