title: Nano-TiO2affects Cu speciation, extracellular enzyme activity, and bacterial communities in sediments.
abstract: In aquatic ecosystems, titanium dioxide nanoparticles (nano-TiO2) coexist with heavy metals and influence the existing forms and toxicities of the metal in water. However, limited information is available regarding the ecological risk of this coexistence in sediments. In this study, the effect of nano-TiO2on Cu speciation in sediments was investigated using sequential extraction. The microcosm approach was also employed to analyze the effects of the coexistence of nano-TiO2and Cu on extracellular enzyme activity and bacterial communities in sediments. Results showed that nano-TiO2decreased the organic matter-bound fraction of Cu and increased the corresponding residual fraction Cu. As a result, speciation of exogenous Cu in sediments changed. During the course of the 30-day experiment, the presence of nano-TiO2did not affect Cu-induced changes in bacterial community structure. However, the coexistence of nano-TiO2and Cu restrained the activity of bacterial extracellular enzymes, such as alkaline phosphatase and β-glucosidase. The degree of inhibition also varied because of the different properties of extracellular enzymes. This research highlighted the importance of understanding and predicting the effects of the coexistence of nanomaterials and other pollutants in sediments.
authors.affiliation: Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China. Electronic address: fanwh@buaa.edu.cn.
authors.forename: Wenhong
authors.initials: W
authors.lastname: Fan
authors.affiliation: Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
authors.forename: Ruishuang
authors.initials: R
authors.lastname: Peng
authors.affiliation: Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
authors.forename: Yilin
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D001419:Bacteria / Q000201:enzymology; D002681:China; D003300:Copper / Q000737:chemistry / Q000633:toxicity*; D017753:Ecosystem; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D060106:Lakes / Q000737:chemistry / Q000382:microbiology; D019216:Metals, Heavy / Q000737:chemistry / Q000633:toxicity; D059013:Microbial Consortia / Q000187:drug effects; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*; D001617:beta-Glucosidase / Q000378:metabolism*
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D003300:Copper; D014025:Titanium; D000469:Alkaline Phosphatase; D001617:beta-Glucosidase
keywords: Bacterial communities; Cu speciation; Extracellular enzyme activity; Nano-TiO(2); Sediment