Photocatalytic degradation of benzo(a)pyrene by titanium dioxide nanoparticles results in increased toxicity to zebrafish (Danio rerio)
Wednesday, October 9, 2013
Nicholas School Doctoral Student
Division of Environmental Sciences and Policy
Abstract: Titanium dioxide nanoparticles (TiO2 NPs) are currently being investigated for use as a remediation aid at sites contaminated with organic compounds such as polycyclic aromatic hydrocarbons (PAHs). TiO2 NPs have the ability to produce reactive oxygen species when exposed to UV light in aqueous solution which quickly oxidize organic compounds. Little is known about the potential toxicity of the resultant degradation products. The goal of this study was to determine the effects of TiO2 NP photocatalysis on the toxicity of benzo(a)pyrene (BaP) to larval zebrafish. Solutions of BaP, TiO2 NP, and combinations of BaP + TiO2 NP were exposed to simulated sunlight (UV) or low UV incubator lighting (no UV). 5 day post fertilization zebrafish were then exposed to the resultant solutions. In solutions treated with UV, BaP + TiO2 NPs induced more CYP activity than BaP alone. In addition, at higher concentrations, BaP + TiO2 NPs caused mortality in a dose responsive fashion. These results indicate that BaP degraded by TiO2 NP photocatalysis could result in a degradation profile that is more toxic to larval zebrafish than that of un-catalyzed BaP photodegradation or BaP in the absence of UV. Identification of degradation products is currently underway.