Environmental risk of titanium dioxide nanoparticle and cadmium mixture: developmental toxicity assessment in zebrafish (Danio rerio)

The environmental health impact of titanium dioxide nanoparticles (TiO2 NPs) is of emerging concern, but their effects and ecotoxicity resulting from the interaction between TiO2 NPs and metals, such as cadmium (Cd), on aquatic organisms remain limited. Thus, the current study aimed to evaluate the ecotoxic effects of TiO2 NPs and Cd (alone or in co-exposure) on zebrafish embryos and larvae, based on using multiple biomarkers. Embryos were exposed to environmentally relevant TiO2 NPs (0.1, 1.0, and 10 µg L−1) and Cd (10 µg L−1) concentrations, either alone or in a mix, for 168 h, whereas the control group was kept in reconstituted water. Results showed that the isolated TiO2 NPs have low toxicity to zebrafish embryos and larvae. However, Cd — alone or in co-exposure with TiO2 NPs — induced toxic effects in zebrafish, such as cardiotoxicity, as well as morphological and morphometric changes. The present study has shown TiO2 NPs/Cd interactive effects, including decreased toxicity, on the assessed models. Results have evidenced the potential environmental risk of the nanoparticle and metal mixtures, mainly at early vertebrate developmental stages. Graphical abstract