Tartrazine (TZ) is a widely used synthetic azo dye with high aqueous stability, resulting in persistence in wastewater. Photoreactive nanomaterials, principally zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles (NPs), are frequently employed for dye removal under light-exposed conditions; nevertheless, their ecotoxicological consequences are frequently overlooked. The present study evaluates the environmental implications of TZ exposure in a biologically relevant context, establishing a correlation between dye removal practices and oxidative stress in aquatic organisms. Mediterranean mussels (Mytilus galloprovincialis) were subjected to acute 96-h in vivo exposures, including TZ alone (0.2, 2, and 20 mg/L) and in combination with ZnO-NPs (0.02, 0.2, and 2 mg/L) or TiO2-NPs (0.2, 2, and 20 mg/L), across three independent experimental sets. Biomarkers of oxidative stress, namely superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S-transferase (GST), were measured in gill and digestive gland tissues. The results of the study demonstrated that the levels of enzyme activity exhibited significant variation depending on the type and concentration of the exposure (p 2-NPs co-exposure, corresponding to the strongest separation along the primary PCA axis. TiO2-NPs co-exposure elicited the most significant oxidative responses, particularly at elevated concentrations, while ZnO co-exposure generated tissue-specific biochemical profiles with distinctive patterns at high doses. Principal component analysis (PCA) was utilized to validate these patterns, with PC1 accounting for 59.5%-75.5% of the total variance. These findings underscore the necessity of acknowledging potential ecological impacts on nontarget aquatic organisms, despite the apparent reduction of TZ through NP-dye interactions under light exposure. The study emphasizes the necessity to integrate dye degradation efficiency with ecotoxicological assessment, thus providing a framework for more environmentally responsible NP-assisted wastewater treatment strategies.
Can et al. (Sun,) studied this question.