Engineered nanomaterials released from commercial nano-enabled products affect the morphology and behaviour of the zebrafish (D. rerio) embryo

Abstract

The increasing use of nano-enabled products (NEPs) is contributing to nanopollution, with product-released engineered nanomaterials (PR-ENMs) posing varying risks to aquatic organisms. However, data on their environmental biological impacts remain limited. This study investigates the ecotoxicological effects of PR-ENMs, specifically nTiO₂, nZnO, and nAg, released from commercially available NEPs (sunscreens, topical creams, and socks) using zebrafish (Danio rerio) embryos as a vertebrate model. PR-ENMs were generated through simulated consumer-use scenarios and characterised for size, charge and elemental composition to determine their physicochemical profiles. The zebrafish embryo toxicity test was employed to evaluate mortality, developmental abnormalities, and behavioural responses, providing a multi-endpoint assessment. PR-ENMs induced concentration- and material-dependent toxic effects. PR-nZnO and PR-nAg notably triggered both morphological deformities and significant alterations in both spontaneous and stimulus-induced movement, suggesting neurodevelopmental disruption. Ion release contributed substantially to toxicity, with ionic and particulate forms eliciting comparable responses. The integration of behavioural and morphological endpoints enabled the early detection of sublethal effects and provided mechanistic insights into PR-ENM toxicity. These results emphasise the need to incorporate early detection strategies in nanomaterial hazard assessment and highlight the ecological relevance of realistic exposure scenarios. Overall, this study advances the understanding of PR-ENMs' interactions with aquatic biota and supports more predictive and ethically responsible toxicological evaluations. Further studies are, however, recommended to elucidate the effects in complex environmental systems.