Life cycle exposure to titanium dioxide nanoparticles (TiO2-NPs) induces filial toxicity and population decline in the nematode Caenorhabditis elegans.

Titanium dioxide nanoparticle (TiO₂-NP) exposure has raised significant concern due to their potential toxicity and adverse ecological impacts. Despite their ubiquitous presence in various environmental compartments, the long-term consequences of TiO₂-NPs remain poorly understood. In this study, we combined data of in vivo toxicity and modeling to investigate the potential negative impacts of TiO₂-NP exposure. We employed the nematode Caenorhabditis elegans, an environmental organism, to conduct a full life cycle TiO₂-NP toxicity assays. Moreover, to assess the potential impact of TiO₂-NP toxicity on population dynamics, we applied a stage-constructed matrix population model (MPM). Results showed that TiO₂-NPs caused significant reductions in reproduction, survival, and growth of parental C. elegans (P0) at the examined concentrations. Moreover, these toxic effects were even more pronounced in the subsequent generation (F1) when exposed to TiO₂-NPs. Furthermore, parental TiO₂-NP exposure resulted in significant toxicity in non-exposed C. elegans progeny (TiO₂-NPs free), adversely affecting their reproduction, survival, and growth. MPM analysis revealed decreased transition probabilities of surviving (Pi), growth (Gi), and fertility (Fi) in scenarios with TiO₂-NP exposure. Additionally, the population growth rate (λ_max) was found to be less than 1 in both P0 and F1, indicating a declining population trend after successive generations. Sensitivity analysis pinpointed L1 larvae as the most vulnerable stage, significantly contributing to the observed population decline in both P0 and F1 generations under TiO₂-NP exposure. Our findings provide insight into the potential risk of an environmental organism like nematode by life cycle exposure to TiO₂-NPs. [ABSTRACT FROM AUTHOR]