Influence of humic acid on titanium dioxide nanoparticle toxicity to developing zebrafish.
Titanium dioxide nanoparticle (TiO2NP) suspension stability can be altered by adsorption of dissolved organic matter (DOM). This is expected to impact their environmental fate and bioavailability. To date, the influence of DOM on the toxicity of TiO2NPs to aquatic vertebrates has not been reported. We examined the impact of Suwannee River humic acid (HA) on the toxicity of TiO2NPs to developing zebrafish (Danio rerio) in the dark and under simulated sunlight illumination. Adsorption of HA increased suspension stability and decreased TiO2NP exposure. TiO2NPs were more toxic in the presence of HA. In the absence of simulated sunlight, a small but significant increase in lethality was observed in fish exposed to TiO2NPs in the presence of HA. Under simulated sunlight illumination, photocatalytic degradation of HA reduced suspension stability. Despite the lower concentrations of Ti associated with fish in the treatments containing HA, under simulated sunlight illumination, median lethal concentrations were lower and oxidative DNA damage was elevated relative to fish exposed to TiO2NPs in the absence of HA. This study demonstrates the importance of considering environmental factors (i.e., exposure to sunlight, adsorption of DOM) when assessing the potential risks posed by engineered nanomaterials in the environment.
Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin 53706, USA.
Sarah P
SP
Yang
Ofek
O
Bar-Ilan
Richard E
RE
Peterson
Warren
W
Heideman
Robert J
RJ
Hamers
Joel A
JA
Pedersen
D000818:Animals; D004777:Environment; D006812:Humic Substances; D053768:Metal Nanoparticles / Q000633:toxicity*; D014025:Titanium / Q000633:toxicity*; D015027:Zebrafish
D006812:Humic Substances; C009495:titanium dioxide; D014025:Titanium