title: Comparative toxicity of nanoparticulate/bulk Yb₂O₃ and YbCl₃ to cucumber (Cucumis sativus).
abstract: With the increasing utilization of nanomaterials, there is a growing concern for the potential environmental and health effects of them. To assess the environmental risks of nanomaterials, better knowledge about their fate and toxicity in plants are required. In this work, we compared the phytotoxicity of nanoparticulate Yb(2)O(3), bulk Yb(2)O(3), and YbCl(3)·6H(2)O to cucumber plants. The distribution and biotransformation of the three materials in plant roots were investigated in situ by TEM, EDS, as well as synchrotron radiation based methods: STXM and NEXAFS. The decrease of biomass was evident at the lowest concentration (0.32 mg/L) when exposed to nano-Yb(2)O(3), while at the highest concentration, the most severe inhibition was from YbCl(3). The inhibition was dependent on the actual amount of toxic Yb uptake by the cucumber plants. In the intercellular regions of the roots, Yb(2)O(3) particles and YbCl(3) were all transformed to YbPO(4). We speculate that the dissolution of Yb(2)O(3) particles induced by the organic acids exuded from roots played an important role in the phytotoxicity. Only under the nano-Yb(2)O(3) treatment, YbPO(4) deposits were found in the cytoplasm of root cells, so the phytotoxicity might also be attributed to the Yb internalized into the cells.
authors.affiliation: Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Ma
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiao
authors.initials: X
authors.lastname: He
authors.forename: Zhi
authors.initials: Z
authors.lastname: Guo
authors.forename: Renzhong
authors.initials: R
authors.lastname: Tai
authors.forename: Yayun
authors.initials: Y
authors.lastname: Ding
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Chai
mesh_terms: D000704:Analysis of Variance; D018533:Biomass; D002712:Chlorides / Q000493:pharmacokinetics / Q000633:toxicity*; D018553:Cucumis sativus; D017348:Microscopy, Electron, Scanning Transmission; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000633:toxicity*; D018517:Plant Roots / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D036226:Seedlings / Q000187:drug effects* / Q000378:metabolism; D013052:Spectrometry, X-Ray Emission; D056928:X-Ray Absorption Spectroscopy; D015018:Ytterbium / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D002712:Chlorides; C044841:ytterbium trichloride; D015018:Ytterbium