Institute of Chemistry, UNICAMP, PO Box 6154, 13083-970, Campinas, SP, Brazil.
J Hazard Mater. 2012 Apr 15;211-212:436-42. doi: 10.1016/j.jhazmat.2011.12.075. Epub 2012 Jan 9.
Currently, there are a large number of products (sunscreen, pigments, cosmetics, plastics, toothpastes and photocatalysts) that use TiO(2) nanoparticles. Due to this large production, these nanoparticles can be released into the aquatic, terrestrial and aerial environments at relative high concentration. TiO(2) in natural water has the capacity to harm aquatic organisms such as the Daphnia (Cladocera) species, mainly because the photocatalytic properties of this semiconductor. However, very few toxicity tests of TiO(2) nanoparticles have been conducted under irradiation. The aim of this study was to evaluate anatase and rutile TiO(2) toxicity to Daphnia similis exploring their photocatalytic properties by incorporating UV A and visible radiation as a parameter in the assays. Anatase and rutile TiO(2) samples at the highest concentration tested (100 mg L(-1)) were not toxic to D. similis, neither in the dark nor under visible light conditions. The anatase form and a mixture of anatase and rutile, when illuminated by a UV A black light with a peak emission wavelength of 360 nm, presented photo-dependent EC50 values of 56.9-7.8 mg L(-1), which indicates a toxicity mechanism caused by ROS (reactive oxygen species) generation.
目前，有大量的产品（防晒霜、颜料、化妆品、塑料、牙膏和光催化剂）使用 TiO(2)纳米颗粒。由于这种大规模的生产，这些纳米颗粒可能会以相对较高的浓度释放到水、陆和空气环境中。TiO(2)在天然水中具有伤害水生物如枝角类（甲壳纲）物种的能力，主要是因为这种半导体的光催化特性。然而，在光照条件下，TiO(2)纳米颗粒的毒性测试非常少。本研究的目的是评估锐钛矿和金红石 TiO(2)对 Daphnia similis 的毒性，通过将紫外 A 和可见光辐射作为实验参数来探索它们的光催化特性。在最高测试浓度（100 mg L(-1))下，锐钛矿和金红石 TiO(2)样品对 D. similis 既没有在黑暗中也没有在可见光条件下产生毒性。当用峰值发射波长为 360nm 的紫外 A 黑光照射时，锐钛矿形式和锐钛矿与金红石的混合物呈现出光依赖性 EC50 值为 56.9-7.8mg L(-1)，这表明 ROS（活性氧）生成引起的毒性机制。
