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Impact of solar UV radiation on toxicity of ZnO nanoparticles through photocatalytic reactive oxygen species (ROS) generation and photo-induced dissolution
Citation:
Ma, H., L. Wallis, S. Diamond, S. Li, J. Canas-Carrell, AND A. Parra. Impact of solar UV radiation on toxicity of ZnO nanoparticles through photocatalytic reactive oxygen species (ROS) generation and photo-induced dissolution. ENVIRONMENTAL POLLUTION. Elsevier Science Ltd, New York, NY, 193:165-172, (2014).
Impact/Purpose:
The present study demonstrates the importance of solar UV radiation as an environmental factor on the toxicity of engineered ZnO nanoparticles, through both photocatalytic ROS generation and photo-enhanced dissolution. Our findings suggest that hazard and risk assessment for ZnO nanoparticles must take into consideration of solar UV radiation.
Description:
The present study investigated the impact of solar UV radiation on ZnO nanoparticle toxicity through photocatalytic ROS generation and photo-induced dissolution. Toxicity of ZnO nanoparticles to Daphnia magna was examined under laboratory light versus simulated solar UV radiation (SSR). Photocatalytic ROS generation and particle dissolution were measured on a time-course basis. Two toxicity mitigation assays using CaCl2 and N-acetylcysteine were performed to differentiate the relative importance of these two modes of actions. Enchanced ZnO nanoparticle toxicity under SSR was in parallel with phorocatalytic ROS generation and enhanced particle dissolution. Toxicity mitigation by CaCl2 to a less extent under SSR than under lab light demonstrates the role of ROS generation in ZnO toxicity. Toxicity mitigation by N-acetylcysteine under both irradiation conditions confirms the role of particle dissolution and ROS generation. These findings demonstrate the importance of considering environmental solar UV radiation when assessing ZnO nanoparticle toxicity and risk in aquatic systems.
