Non-monotonic concentration–response relationship of TiO2 nanoparticles in freshwater cladocerans under environmentally relevant UV-A light

Title
Non-monotonic concentration–response relationship of TiO2 nanoparticles in freshwater cladocerans under environmentally relevant UV-A light
Author
윤태현
Keywords
Filter apparatus; Non-monotonicity; Oxidative stress; Reactive oxygen species
Issue Date
2014-02
Publisher
Elsevier B.V
Citation
Ecotoxicology and Environmental Safety, 2014, 101, P.240-247
Abstract
The effects of UV-A on the toxicity of TiO2 nano-particles (NPs) were evaluated using Moina macrocopa and Daphnia magna under environmentally relevant level of UV-A. The waterfleas were exposed to TiO2 NPs with different sizes of ~298 nm, ~132 nm, or ~72 nm for up to 48 h, with or without UV-A light. Whole body reactive oxygen species and transcription of antioxidant enzyme genes were measured, as well as the survival of the waterflea. In the presence of UV-A, the survival rates of M. macrocopa significantly decreased in concentration dependent way until ~1 mg/L TiO2 NPs, but the survivals were reversed at greater concentrations. This peculiar non-monotonic trend of concentration?response relationship might be explained by changes of particle size under different light conditions. TiO2 NPs within a certain size range could be trapped in the filter apparatus and exert toxicity, and the NPs of greater size were subject to either precipitation or ingestion leading to no or little toxicity. Observed TiO2 toxicity was associated with oxidative stress in the filter apparatus. The results of this study showed that the size change due to UV-A irradiation should be considered in evaluation of ecological risks of TiO2 NP.
URI
https://www.sciencedirect.com/science/article/pii/S0147651314000050?via%3Dihubhttp://repository.hanyang.ac.kr/handle/20.500.11754/73311
ISSN
0147-6513
DOI
10.1016/j.ecoenv.2014.01.002
Appears in Collections:
COLLEGE OF NATURAL SCIENCES[S](자연과학대학) > CHEMISTRY(화학과) > Articles
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