Investigation of the effects of metal oxide nanoparticle mixtures on Danio rerio and Xenopus laevis embryos

ABSTRACT In this study, the toxic effects of single TiO2, ZnO and Fe2O3 nanoparticles (NPs) and their binary and ternary combinations on the embryonic development of Xenopus laevis and Danio rerio were evaluated. It was aimed to determine the median lethal concentrations, growth retardation and developmental malformation effects and the effects of mixed nanoparticle exposure to selected enzyme biomarkers resulting from the exposure of embryos to NPs. The results showed that ZnO NPs, which are the most toxic according to the highest lethality level, cause developmental delay and malformations. The Fe2O3 and TiO2 NPs caused growth retardation only in D. rerio embryos. It was determined that double and triple combinations of NPs did not cause significant lethality in both species. Biochemical markers showed that mixed NPs could lead to greater toxicity compared to single exposures. The results also revealed that TiO2 or Fe2O3 NPs caused an increase in toxicity when co-existing with ZnO NP due to additive effects. Overall, the results showed that D. rerio was more susceptible to NP exposure in terms of growth and mortality than X. laevis. However, studies that are more comprehensive are needed to better understand the toxicity mechanism of metal oxide NP mixtures.