U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN, USA.
U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN, USA.
Environ Pollut. 2015 Oct;205:327-32. doi: 10.1016/j.envpol.2015.06.020. Epub 2015 Jun 26.
As a semiconductor with wide band gap energy, TiO2 nanoparticles (nano-TiO2) are highly photoactive, and recent efforts have demonstrated phototoxicity of nano-TiO2 to aquatic organisms. However, a dosimetry model for the phototoxicity of nanomaterials that incorporates both direct UV and photo-activated chemical toxicity has not yet been developed. In this study, a set of Hyalella azteca acute toxicity bioassays at multiple light intensities and nano-TiO2 concentrations, and with multiple diel light cycles, was conducted to assess how existing phototoxicity models should be adapted to nano-TiO2. These efforts demonstrated (a) adherence to the Bunsen-Roscoe law for the reciprocity of light intensity and time, (b) no evidence of damage repair during dark periods, (c) a lack of proportionality of effects to environmental nano-TiO2 concentrations, and (d) a need to consider the joint effects of nano-TiO2 phototoxicity and direct UV toxicity.
作为一种具有宽能带隙能量的半导体，TiO2 纳米粒子（纳米-TiO2）具有很高的光活性，最近的研究表明纳米-TiO2 对水生生物具有光毒性。然而，目前还没有开发出一种将直接紫外线和光激活化学毒性都包含在内的纳米材料光毒性剂量测定模型。在这项研究中，进行了一系列的 Hyalella azteca 急性毒性生物测定，在多个光强度和纳米-TiO2 浓度下，并进行了多个昼夜光周期，以评估现有的光毒性模型应该如何适应纳米-TiO2。这些努力表明：（a）光强度和时间的互易性符合本生-罗胥克定律；（b）在黑暗期没有证据表明有损害修复；（c）对环境纳米-TiO2 浓度的影响没有比例关系；（d）需要考虑纳米-TiO2 光毒性和直接紫外线毒性的联合效应。
