Van Koetsem Frederik, Xiao Yi, Luo Zhuanxi, Du Laing Gijs
Laboratory of Analytical Chemistry and Applied Ecochemistry, Department of Applied Analytical and Physical Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, Belgium.
Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, China.
Environ Sci Pollut Res Int. 2016 Mar;23(6):5277-87. doi: 10.1007/s11356-015-5708-8. Epub 2015 Nov 13.
In this study, the potential association of (citrate-stabilized) Ag (14.1 ± 1.0 nm) and CeO2 (6.7 ± 1.2 nm) engineered nanoparticles (ENPs), or their ionic counterparts, with the submerged aquatic plant Elodea canadensis, was examined and, in particular, parameters affecting the distribution of the nanoparticles (or metal ions) between plant biomass and the water phase were assessed using five distinct aqueous matrices (i.e. tap water, 10 % Hoagland's solution and three natural surface water samples). Individual plants were exposed to varying concentrations of Ag and CeO2 ENPs or Ag(+) and Ce(3+) ions during 72-h-lasting batch experiments. A dose-dependent increase of silver or cerium in plant biomass was observed for both the nanoparticles and the ions, whereby exposure to the latter systematically resulted in significantly higher biomass concentrations. Furthermore, the apparent plant uptake of CeO2 ENPs appeared to be higher than that for Ag ENPs when comparing similar exposure concentrations. These findings suggest that association with E. canadensis might be affected by particle characteristics such as size, composition, surface charge or surface coating. Moreover, the stability of the ENPs or ions in suspension/solution may be another important aspect affecting plant exposure and uptake. The association of the nanoparticles or ions with E. canadensis was affected by the physicochemical characteristics of the water sample. The silver biomass concentration was found to correlate significantly with the electrical conductivity (EC), dry residue (DR) and Cl(-), K, Na and Mg content in the case of Ag ENPs or with the EC, inorganic carbon (IC) and Cl(-), NO3 (-), Na and Mg content in the case of Ag(+) ions, whereas significant relationships between the cerium biomass concentration and the EC, DR, IC and Ca content or the pH, EC, DR, IC and Cl(-), Ca and Mg content were obtained for CeO2 ENPs or Ce(3+) ions, respectively. Results also indicated that the Ag ENPs and Ag(+) ions might potentially be toxic towards E. canadensis whereas no evidence of phytotoxicity was noted in the case of CeO2 ENPs or Ce(3+) ions.
在本研究中，考察了（柠檬酸盐稳定的）银（14.1±1.0纳米）和二氧化铈（6.7±1.2纳米）工程纳米颗粒（ENPs）或其离子对应物与沉水水生植物加拿大伊乐藻之间的潜在关联，特别是使用五种不同的水性基质（即自来水、10%霍格兰溶液和三个天然地表水样品）评估了影响纳米颗粒（或金属离子）在植物生物量和水相之间分布的参数。在持续72小时的批次实验中，将单株植物暴露于不同浓度的银和二氧化铈ENPs或银离子（Ag(+)）和铈离子（Ce(3+)）中。对于纳米颗粒和离子，均观察到植物生物量中银或铈呈剂量依赖性增加，其中暴露于离子时系统性地导致生物量浓度显著更高。此外，当比较相似的暴露浓度时，二氧化铈ENPs在植物中的表观吸收似乎高于银ENPs。这些发现表明，与加拿大伊乐藻的关联可能受颗粒特性如尺寸、组成、表面电荷或表面涂层的影响。此外，ENPs或离子在悬浮液/溶液中的稳定性可能是影响植物暴露和吸收的另一个重要方面。纳米颗粒或离子与加拿大伊乐藻的关联受水样的物理化学特性影响。发现银生物量浓度与银ENPs情况下的电导率（EC）、干残渣（DR）以及Cl(-)、K、Na和Mg含量显著相关，或者与银离子（Ag(+)）情况下的EC、无机碳（IC）以及Cl(-)、NO3 (-)、Na和Mg含量显著相关，而对于二氧化铈ENPs或铈离子（Ce(3+)），分别获得了铈生物量浓度与EC、DR、IC和Ca含量之间，或者与pH、EC、DR、IC和Cl(-)、Ca和Mg含量之间的显著关系。结果还表明，银ENPs和银离子（Ag(+)）可能对加拿大伊乐藻具有潜在毒性，而在二氧化铈ENPs或铈离子（Ce(3+)）情况下未发现植物毒性的证据。
