this conclusion. In our study non of the results of the Ames test (+S9 and –S9) exceeded the critical value 2.0 and all the quotients ranged below 1.6, therefore no mutagenic activity was observed in any of drinking water samples. However an increase in induction factor can be seen in presence of S9 homogenate (+S9), but the statistical significances of genotoxic potentials in any of the water samples according to the negative control were not proven (p > 0.05).
According to EPA guidelines and Zi