Zhang Hong, Huang Qing, Xu An, Wu Lijun
a Institute of Technical Biology and Agriculture Engineering, Key Laboratory of Ion Beam Bioengineering, Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province, Hefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei , China , and.
b National Synchrotron Radiation Laboratory, and School of Nuclear Science and Technology, University of Science & Technology of China , Hefei , China.
Nanotoxicology. 2016 Oct;10(8):1177-87. doi: 10.1080/17435390.2016.1196252. Epub 2016 Jun 20.
Zinc oxide nanoparticles (ZnO NPs) are one of the most abundantly applied nanomaterials in nanotechnology-based industries and they may cause unexpected environmental and health risks with their physicochemical transformations in the environment. Currently, there is still a lack of the in-depth understanding of the toxicity of aged ZnO NPs to aquatic organisms, particularly demanding quantitative analysis of the physicochemical transformations to distinguish their contributions in the toxicity assessment. For this purpose, therefore, we initiated the study of the toxicity of aged ZnO NPs to the model aquatic microalga, i.e. Chlorella vulgaris, and with the aid of spectroscopic tools for characterization and quantification of the physicochemical transformations, we scrutinized the toxicity variations for ZnO NPs with different aging times. As a result, we found that the toxicity altered in an abnormal manner with the aging time, i.e. the toxicity of aged ZnO NPs for 30 days showed the higher toxicity to the green alga than the fresh ZnO NPs or the ZnO NPs aged for longer time (e.g. 120 and 210 days). Through spectroscopic tools such as XRD, FTIR and Raman spectroscopy, we made both the qualitative and quantitative assessments of the physicochemical changes of the ZnO NPs, and confirmed that in the early stage, the toxicity mainly stemmed from the release of zinc ions, but with longer aging time, the neoformation of the nanoparticles played the critical role, leading to the overall reduced toxicity due to the less toxic hydrozincite and zinc hydroxide in the transformed compounds.
氧化锌纳米颗粒（ZnO NPs）是纳米技术产业中应用最为广泛的纳米材料之一，它们在环境中的物理化学转化可能会带来意想不到的环境和健康风险。目前，对于老化的ZnO NPs对水生生物的毒性仍缺乏深入了解，尤其需要对物理化学转化进行定量分析，以区分它们在毒性评估中的作用。因此，为了实现这一目的，我们开展了老化的ZnO NPs对模式水生微藻——普通小球藻毒性的研究，并借助光谱工具对物理化学转化进行表征和定量，仔细研究了不同老化时间的ZnO NPs的毒性变化。结果发现，毒性随老化时间呈异常变化，即老化30天的ZnO NPs对绿藻的毒性高于新鲜的ZnO NPs或老化时间更长（如120天和210天）的ZnO NPs。通过XRD、FTIR和拉曼光谱等光谱工具，我们对ZnO NPs的物理化学变化进行了定性和定量评估，并证实早期毒性主要源于锌离子的释放，但随着老化时间延长，纳米颗粒的新形成起关键作用，由于转化产物中低毒性的水锌矿和氢氧化锌，导致整体毒性降低。
