Toxicity evaluation of the azo dyes disperse red 1, disperse orange 1 and disperse red 13 as well as their chlorinated by products using the salmonella mutagenicity assay and cell culture

Abstract

The release of mutagenic dyes in the environment by dying processing plants is a great concern all over the world, mainly when these compounds reach the intake of drinking water treatment plants (DWTP). Recently, a Japanese group shows the formation of non colored mutagenic compounds generated by the reaction of chlorine and azo dyes (PBTAs), with potency around 50 times higher than the original dye. The toxicity of azo compounds depends on the nature and position of the substituent with respect to both the aromatic rings and the amino nitrogen atom. Because minor changes in the molecule can drastically modify their mutagenic and carcinogenic activities, it is important that each azo dye released into the market is adequately tested. The mutagenicity salmonella assay, using strains that are sensitive to different chemical classes and exogenous metabolic systems can be used not only for the mutagenic evaluation, but also to elucidate the role of different enzymes in the mutagenicity as well as the possible target organs of this effect. The HepG2 cells are useful tool to the toxicity evaluation because they can be used for the detection of micronucleus and apoptosis cell death. Also, these cells can be used as exogenous metabolic system in order to simulate the activity of human liver. This project proposes the preliminary toxicity evaluation using the bioassays with salmonella and HepG2 cells to verify the mutagenic activity, ability to induce apoptosis and the elucidation of the possible target organs of the dyes disperse red 1, disperse orange 1 e disperse red 13. (AU)