Application of an alternative approach for using the SOS chromotest to screen complex indeterminate mixtures.

We report on the application of an alternative approach to screen two complex indeterminate mixtures for genotoxic activity with the SOS chromotest, a simple quantitative colorimetric short-term bacterial genotoxicity assay. Considering the mixtures as a complex matrix, we evaluated the shape of the dose response curve of the direct acting reference genotoxin 4-nitroquinoline-1-oxide (4-NQO) with and without the matrix and found for one mixture a previously unrecognized genotoxic potential.