Alizarin Dye: Toxicity, Genotoxicity, and Histopathological Alterations in Model Organisms

Alizarin is an anthraquinone red dye from natural or synthetic sources, widely used in textiles. Effluents of this activity can contain residual dyes, which may contaminate the aquatic environment. Studies report alizarin's aquatic toxicity, mutagenic, and carcinogenic effects. This study aimed to complement the aquatic toxicity evaluation and confirm its ability to cause genotoxicity in alternative models. Acute toxicity was performed with crustaceans, mussels, and fish embryos, while chronic toxicity was assessed in algae. Light effects on toxicity were evaluated using Daphnia similis. Histopathological effects on the gonads of Mytilus galloprovincialis and somatic mutations and sperm genotoxicity in Parhyale hawaiensis were investigated. Mutagenicity was confirmed using a miniaturized Ames test. The effect concentration 50% (EC₅₀) for D. similis was 90.3, 105, and 68.6 μg L^-1 for photoperiod (16 h light:8 h dark), light and dark, respectively. For Danio rerio embryos, the lethal concentration 50% (LC₅₀) was 45.8 μg L^-1, and an EC₁₀ of 20.8 μg L^-1 was calculated for sublethal effects. In vivo exposures caused alterations in the digestive gland and gonads of M. galloprovincialis, even in a short-term exposure, and increased the frequency of micronuclei and DNA damage in hemocytes and spermatozoids, respectively, of P. hawaiensis. It was mutagenic in the miniaturized Ames test using strain TA1537 (10% and 30% S9). Alizarin can be classified as a Category 1 acute aquatic toxicity according to the globally harmonized system (GHS). Due to adverse histopathological and DNA effects on reproductive systems in model organisms, it is considered a potential germ cell mutagen.