Fate of CuO and ZnO Nano- and Microparticles in the Plant Environment
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- 作者：Christian O. Dimkpa ; Drew E. Latta ; Joan E. McLean ; David W. Britt ; Maxim I. Boyanov ; Anne J. Anderson
- 刊名：Environmental Science & Technology (ES&T)
- 出版年：2013
- 出版时间：May 7, 2013
- 年：2013
- 卷：47
- 期：9
- 页码：4734-4742
- 全文大小：419K
- 年卷期：v.47,no.9(May 7, 2013)
- ISSN：1520-5851
文摘
The environmental fate of metal oxide particles as a function of size was assessed by comparing the behavior of CuO or ZnO nanoparticles (NPs) to that of the corresponding microparticles (MPs) in a sand matrix, with and without wheat (Triticum aestivum L.) growth. After 14 days of incubation in the planted sand, the CuO and ZnO NPs were increased from their nominal sizes of <50 nm and <100 nm, to 317 nm and 483 nm, respectively. Accordingly, the negative surface charge of colloids present in aqueous extracts from the sand amended with CuO (鈭?7.0 mV) and ZnO (鈭?0.0 mV) NPs was reduced by the presence of plants, to 鈭?9.8 mV and 鈭?.0 mV, respectively. The surface charge of the MPs was not influenced by plants. Plant growth increased dissolution of NPs and MPs of both metal oxides in the sand from <0.3 mg/kg to about 1.0 mg/kg for the CuO products, and from 鈮?.6 mg/kg to between 1.0 and 2.2 mg/kg for the Zn products. The NP or MP products reduced wheat root length by 60% or 50% from control levels; CuO was more toxic than ZnO. X-ray absorption spectroscopy (XAS) analysis showed that treatments with MPs or NPs of ZnO led to similar accumulations of Zn鈥損hosphate species in the shoots, likely from dissolution of ZnO. Exposure to CuO NPs or MPs resulted in similar XAS spectra for Cu in the shoots explained by plant accumulation of both CuO and CuI鈥搒ulfur complexes. These findings demonstrate the similarities between commercial NPs and MPs of CuO or ZnO in wheat plants, with greater root toxicity correlating with smaller particle size. Factors from the sand and the plant modified the aggregation or dissolution of both types of particles, thus, influencing their environmental fates.