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(132) Performance of bacterial genotoxicity tests on effluents; comparison of Mutatox- , SOS-chromo-, and UmuC-test. De Maagd, Gert-Jan1, Eisentraeger, Adolf2, Rila, Jean Paul2, Hamers, Timo3, Klamer, Hans4, Kroon, Sander5, Van Ommen, Ben 6, 1 2 3 4 5 6 ABSTRACT- Whole-Effluent Assessment (WEA) is an instrument that helps to assess the hazard of unknown compounds and mixtures by determining toxic potencies of the whole effluent. In order to concretize the parameter genotoxicity within WEA three bacterial genotoxicity tests: Mutatox- , SOS-chromo-, and UmuC, where evaluated. All three tests quantify primary DNA damage, which is measured as induction of the SOS-DNA repair system, either by a reporter gene, as for the SOS-chromo-, and UmuC-test,or by the restoration of luminescence as for the Mutatox-test. Selection of one of these tests for routinely testing of effluents was performed based on the criteria sensitivity, fitness for quantitative use, reproducibility, practicality, and cost-efficiency. To compare the tests the genotoxicity of five concentrated effluent samples and one concentrated surface water sample were quantified at different concentrations with and without metabolic activation.The results showed that the UmuC-test seems best fit for further use for its higher quantitative sensitivity compared to the SOS-chromo-test. The Mutatox-test is regarded unfit for the routine quantitative assessment of effluents in its current form. This is mainly based on its low reproducibility and the interference of growth with the obtained maximum response, leading to dose-response curves that are hard to interpret.Furthermore, the study showed that the existing UmuC protocols can be improved, especially concerning the additional requirements introduced with effluent testing. Suggested improvements concern color correction, constant solvent concentrations, and the application of Dunnetts test for data interpretation. Key words: effluents, genotoxicity, Whole Effluent Assessment |
