Genotoxicity of degradation products of textile dyes evaluated with rec-assay after PhotoFenton and ligninase treatment.

Fourteen textile and biological dyes, belonging to the azo, triphenylmethane, anthraquinone, heterocyclic, oxazine, and methine/polymethine groups, were degraded using the PhotoFenton treatment (PFT) and the Phanerochaete chrysosporium crude ligninase enzyme (ED) treatment. The genotoxicity of the dyes and of their degradation products were assessed with the rec-assay. We found that the genotoxicity depended on the dye and on the method of degradation. In general, PFT was better than ED in decreasing the genotoxicity. Basic dyes showed complete or maximum loss of genotoxicity, whereas the vat group was more resistant. The azo group showed varied results. Crystal Violet was the only dye whose genotoxicity increased after PFT. Our results suggest that PFT and ED are two effective treatment methods to reduce the genotoxicity of dyes in waste waters.