title: MITIGATION OF Cu(II) PHYTOTOXICITY TO RICE (ORYZA SATIVA) IN THE PRESENCE OF TiO₂ AND CeO₂ NANOPARTICLES COMBINED WITH HUMIC ACID.
abstract: Engineered nanoparticles (NPs) and natural organic matter (NOM) in the environment may interact with background contaminants such as heavy metals and modify their bioavailability and toxicity. In the present study, the combined influences of 2 common NPs (TiO2 and CeO2 ) and humic acid (HA; as a model NOM) on Cu(II) phytotoxicity to rice were investigated by a 3-d root elongation assay performed on filter paper media. The results showed that the adsorption coefficients of bare TiO2 and CeO2 NPs (100 mg/L) toward Cu(2+) are 2.65 and 4.37, respectively, at an initial concentration of 10 mg/L, suggesting that Cu(II) could be strongly adsorbed by NPs, whereas HA-coated TiO2 and CeO2 NPs further enhanced the adsorption coefficients to 4.37 and 6.85, respectively. In addition, compared with Cu-alone treatment, the addition of bare TiO2 and CeO2 NPs (1000 mg/L) increased the length of rice root by 32.5% and 39.0%, respectively; however, the presence of HA-coated TiO2 and CeO2 NPs increased the root length by 90.2% and 100.1%, respectively, which indicated that the mitigation effect of HA-coated NPs on Cu(II) phytotoxicity was more visible than that of bare NPs. The results demonstrated that coexistence of NPs and HA significantly alleviated Cu(II) phytotoxicity as a result of a decrease in bioavailable soluble Cu(II) concentration, which contributes to an understanding of the potential behavior of NPs in the environment.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Peng
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Huaxiang
authors.initials: H
authors.lastname: Fang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Hai
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Jiabei
authors.initials: J
authors.lastname: Feng
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Dechao
authors.initials: D
authors.lastname: Duan
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Jiyan
authors.initials: J
authors.lastname: Shi
mesh_terms: D000327:Adsorption; D001682:Biological Availability; D002563:Cerium / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry / Q000633:toxicity*; D006812:Humic Substances / Q000032:analysis / Q000633:toxicity*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D012275:Oryza / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D014025:Titanium / Q000737:chemistry; D018675:Toxicity Tests
chemical_list: D004785:Environmental Pollutants; D006812:Humic Substances; C009495:titanium dioxide; D002563:Cerium; C030583:ceric oxide; D003300:Copper; D014025:Titanium
keywords: CeO2; Copper; Humic acid; Nanoparticles; Phytotoxicity; TiO2