Behavior of Titanium Dioxide Nanoparticles in the Presence of Common Contaminant Bisphenol a

TiO₂ possesses the ability to transform organic compounds, making it a valuable tool for water treatment and remediation. However, before employed for such applications, it is necessary to characterize the fate of these nanomaterials, namely their potential toxicity and the interactions in which they may be involved. In this work coexposures of bisphenol A (BPA) with various TiO₂ nanomaterials (anatase, rutile, 70% anatase/30% rutile, and manganese-doped) were evaluated. The reactions between these NPs and bisphenol A, a model for a common water contaminant, were characterized by dynamic light scattering (DLS, Malvern Instruments). DLS measurements were size behavior and change in zeta potential. Solutions in .02 um filtered fish water of 10mg/L TiO₂ and varying concentrations of 0, 10 and 20 mg/L BPA were analyzed over a 24hour period by DLS. Results suggest that bisphenol A and TiO2 react in common fishwater. Additionally, environmental impact in biological systems was assessed in an embryonic zebrafish model. Dechorionated embryos were exposed to 2, 6, 10, 16, and 20 mg/L of BPA with 10mg/L of each nanomaterial, then sublethal endpoints and mortality were assessed at 24hpf and 120hpf. These data suggest the reaction between bisphenol A and TiO2 NPs led to an increased toxicity to the dechorionated embryos at endpoints 24 and 120 hpf. We hypothesize that there is a concentration-dependent interaction between BPA and TiO₂ nanomaterials, which causes the rapid change in particle size and altered toxicity to developing zebrafish embryos.