| Abstract: | The release of mutagens from 7 carbon black-based leather dyes and from leather samples at various stages of finishing was determined. After vigorous treatment with toluene, 4 commercial dyes yelded mutagenic extracts on Salmonella typhimurium in the presence of microsomal enzymes. Only in one case were the responsible chemicals identified as polycyclic aromatic hydrocarbons. The low bioavailability of mutagens contained in carbon black and their low mutagenic activity suggest that the risk associated with the use of these dyes is probably negligible. Soxhlet extracts with ethanol from finished leather were mutagenic on strain TA98 of Salmonella typhimurium in the absence of S9 mix. Analysis of extracts of leather samples at various intermediate stages of processing showed that mutagenic activity was detectable after the colouring process. The responsible compound was identified as a nitroazo dye (Colour Index: Acid Brown 83), with a mutagenic potential of about 4 revertant/micrograms. Eighteen commercial tannins containing mainly Cr(III) sulphates were assessed for genotoxicity. Most were contaminated with Cr(VI), a known mutagenic and carcinogenic agent, at levels sufficient to induce an increased frequency of SCE (sister chromatid exchanges) in mammalian cells (CHO, chinese hamster ovary) tested in vitro. |
