ISTerre, Université de Grenoble 1, CNRS, 38041 Grenoble, France.
European Synchrotron Radiation Facility, Beamline ID21, Grenoble, France.
J Hazard Mater. 2014 May 30;273:17-26. doi: 10.1016/j.jhazmat.2014.03.014. Epub 2014 Mar 24.
Engineered TiO2 nanoparticles (TiO2-NPs) are present in a large variety of consumer products, and are produced in largest amount. The building industry is a major sector using TiO2-NPs, especially in paints. The fate of NPs after their release in the environment is still largely unknown, and their possible transfer in plants and subsequent impacts have not been studied in detail. The foliar transfer pathway is even less understood than the root pathway. In this study, lettuces were exposed to pristine TiO2-NPs and aged paint leachate containing TiO2-NPs and microparticles (TiO2-MPs). Internalization and in situ speciation of Ti were investigated by a combination of microscopic and spectroscopic techniques. Not only TiO2-NPs pristine and from aged paints, but also TiO2-MPs were internalized in lettuce leaves, and observed in all types of tissues. No change in speciation was noticed, but an organic coating of TiO2-NPs is likely. Phytotoxicity markers were tested for plants exposed to pristine TiO2-NPs. No acute phytotoxicity was observed; variations were only observed in glutathione and phytochelatin levels but remained low as compared to typical values. These results obtained on the foliar uptake mechanisms of nano- and microparticles are important in the perspective of risk assessment of atmospheric contaminations.
工程化的 TiO2 纳米颗粒（TiO2-NPs）存在于大量的消费产品中，并且其产量最大。建筑行业是使用 TiO2-NPs 的主要领域，特别是在涂料中。纳米颗粒在环境中释放后的命运仍然很大程度上未知，它们在植物中的可能转移及其随后的影响也没有得到详细研究。叶部转移途径甚至比根部途径了解得更少。在这项研究中，生菜暴露于原始 TiO2-NPs 和含有 TiO2-NPs 和微粒（TiO2-MPs）的老化涂料浸出物中。通过微观和光谱技术的结合，研究了 Ti 的内化和原位形态。不仅原始和老化涂料中的 TiO2-NPs，而且 TiO2-MPs 也被生菜叶片内化，并在所有类型的组织中观察到。没有注意到形态的变化，但可能存在 TiO2-NPs 的有机涂层。对暴露于原始 TiO2-NPs 的植物进行了植物毒性标志物测试。没有观察到急性植物毒性；仅观察到谷胱甘肽和植物螯合肽水平的变化，但与典型值相比仍然较低。这些关于纳米和微粒叶部摄取机制的研究结果对于大气污染风险评估具有重要意义。
