Statistical analysis for the Ames and Zimmerman test and interpretation of the results
Genotoxic activities for both tests were expressed as induction factors (induction factor of reversions and conversions) i.e. as multiples of the background levels. Statistical significance was evaluated with Kruskal-Walis test (non-parametric ANOVA) for differences between treatment groups and Dunnett’s C multiple comparison for differences to the negative control.
The interpretation of the Ames test results followed OECD 471 guidelines24 and EPA Health Effects Tests Guidelines (OPPTS 870.5265)25 for genotoxicity testing of chemicals. The results of the Zimmermann test were interpreted according to the EPA Health Effects Tests Guidelines (OOPTS 870.5575) and as described by Zimmermann.12,26