Nanomaterials have attracted considerable interest owing to their unique physicochemical properties.The wide application of nanomaterials has raised many concerns about their potential risks to human health and the environment.Metal oxide nanopartides（MONPs）,one of the main members of nanomaterials,have been applied in various fields,such as food,medicine,cosmetics,and sensors.This review highlights the bio-toxic effects of widely applied MONPs and their underlying mechanisms.Two main underlying toxicity mechanisms,reactive oxygen species（ROS）-and non-ROS-mediated toxidties,of MONPs have been widely accepted.ROS activates oxidative stress,which leads to lipid peroxidation and cell membrane damage.In addition,ROS can trigger the apoptotic pathway by activating caspase-9 and-3.Non-ROS-mediated toxicity mechanism includes the effect of released ions,excessive accumulation of NPs on the cell surface,and combination of NPs with specific death receptors.Furthermore,the combined toxicity evaluation of some MONPs is also discussed.Toxicity may dramatically change when nanomaterials are used in a combined system because the characteristics of NPs that play a key role in their toxicity such as size,surface properties,and chemical nature in the complex system are different from the pristine NPs.
In this study, we have investigated the degradation and primary radiolytic degradation mechanism of 4-tert-octylphenol (4-t-OP) by using of electron beam (EB) -irradiation. The results show that at an absorbed dose of 10 kGy and an initial concentration of 25 mg·L -1 , the degradation of 4-t-OP in a methanol/water reduction system is higher than in a acetonitrile/water oxidation system by 19.4% and higher than in an acetone/water system by 26.8%, which is due to both of ·OH and e aq - playing an important role in the decomposition of 4-t-OP, although the latter is more effective. The degradation rate of 4-t-OP will decrease with increment of absorbed dose in a methanol/water solution, and increase with decrement of initial concentration at a constant absorbed dose. The degradation efficiency will also decrease with the addition of anions and H 2 O 2 into the solution. A system saturated with N 2 will make an increment in the degradation of 4-t-OP. The pH value of solution has been also found to affect the degradation efficiency, while the degradation is more efficient in alkaline conditions. Finally, the initial products involved in degradation reaction have been determined to be ethylbenzene, styrene, bicyclo[4.2.0]octa-1,3,5-triene, 2,2,4-trimethylpentane and p-tert-butyl-phenol, which may arise from e aq - attack at the position of the alkyl side chain of 4-t-OP molecule. The results have been revealed that EB irradiation is a promising method for degradation of 4-t-OP, and e aq - may be main reactive species to attack at the position of the alkyl side chain of 4-t-OP.
WANG Liang WU Minghong XU Gang LIN Ning BU Tingting ZHENG Jisan TANG Liang
Ambient coarse particles （diameter 1.8-10 μm）, fine particles （diameter 0.1-1.8 μm）, and ultrafine particles （diameter 〈 0.1 μm） in the atmosphere of the city of Shanghai were sampled during the summer of 2008 （from Aug 27 to Sep 08）. Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy （SEM/EDX）. Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence （SRXRF）. Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 ± 2.18, 8.82 ± 3.52, and 2.02 ± 0.41 μg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.
Senlin LuRui ZhangZhenkun YaoFei YiJingjing RenMinghong WuMan FengQingyue Wang
An analytical method is presented for the quantification of seven Polybrominated Diphenyl Ethers （PBDEs） in ur...
Minghong Wu 1 , Zuyi Chen 1 , Jing Ma 1 , Jianqiu Lei 2 1 School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China 2 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, P. R. China
Bioreactivity of single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) was assessed...
Senlin LU 1 , Jingjing REN 1 , Fei YI 1 , Xiaojie HAO 1 , Shinich YONEMOCHI 2 , Xiaoju WANG 2 1.School of Environmental Sciences and Chemical Engineering Shanghai University Shanghai 200444, China 2.Center for Environmental Science in Saitama, Saitama 374-0115, Japan
