Chuan Fu

Heavy Metal Contamination in the Water-Level Fluctuating Zone of the Yangtze River within Wanzhou Section, China

The distribution, potential ecological hazards, and homologous relativity of heavy metals in the water-level fluctuating zone (WLFZ) of the Yangtze River within the Wanzhou Section (YRWS) were investigated. The heavy metal content (Cd, Cu, Cr, and Ni) of the surface soil was analysed via atomic absorption spectroscopy. The potential ecological hazards of the heavy metals in the WLFZ soil of YRWS were also evaluated using the classical Lars Hakanson potential ecological risk index method, and the relevance of the heavy metals in the soil was investigated. The average Cd, Cr, Cu, and Ni concentrations were 2.14, 35.43, 18.47, and 34.52xa0mg/kg, respectively. The Cd and Ni contents in the soil exceeded the reference values in China by about 28.6- and 1.1-fold, respectively. Correlation analysis shows a highly significant correlation between Cd and Cr, indicating that their sources were the same. The major pollutant was Cd, which reached a very strong ecological hazard level. The potential ecological risk individual coefficients of the four heavy metals were ranked as follows: Cd (802.61) > Cu (4.43) > Ni (4.15) > Cr (1.23). The risk levels in the different regions were ranked as follows: Zhuxi River > mainstream > Mixi valley. The potential ecological risk in the WLFZ within the Zhuxi River was the highest among the regions and poses a certain health risk.

Effect of zinc incorporation manner on a Cu–ZnO/Al2O3 glycerol hydrogenation catalyst

A systematic study was undertaken to investigate the effects of zinc incorporation manner on the textural properties, bulk and surface phase compositions, reduction behaviors, and surface acidity of a copper based glycerol hydrogenation catalyst. The catalyst samples were characterized by N2 physisorption, X-ray photoelectron spectroscopy (XPS), X-ray diffraction, transmission electron microscopy, air thermal gravimetric analysis (air-TGA), H2 thermal gravimetric analysis (H2-TGA), and NH3 temperature-programmed desorption. The glycerol hydrogenation performance of the catalysts was studied in a fixed-bed reactor. The characterization results indicated that the zinc promoter incorporated by using the co-precipitation method could improve the dispersion of copper oxide, and decrease the particle size of the copper oxide. The zinc incorporated with the impregnation method is enriched on the catalyst surface. The catalyst prepared by adding zinc using the co-precipitation method provides higher glycerol conversion and 1,2-propanediol selectivity, and lower selectivity to acetol.

Total nitrogen and pH-controlled chemical speciation, bioavailability and ecological risk from Cd, Cr, Cu, Pb and Zn in the water level-fluctuating zone sediments of the Three Gorges Reservoir

Abstract We investigated the distribution and chemical speciation of Cd, Cr, Cu, Pb and Zn in the water level-fluctuating (WLF) zone of the main stream (MS) and tributaries (ZX and MX) of the Three Gorges Reservoir. We evaluated the ecological risk and pollution level from heavy metals based on the Potential Ecological Risk Index (RI), Risk Assessment Code (RAC), and Ratio of Secondary Phase and Primary Phase (RSP). Our results indicated that the total and bio-available heavy metal contents were higher in the tributaries than in the MS. Moderate pollution from Cd and light pollution from Pb were observed both at the MS and ZX sites, whereas the MX site exhibited a pattern of heavy Cd pollution and light Cr and Pb pollution. In our study area, the results indicated that Cd exhibited a higher ecological risk than did the other heavy metals. Finally, the pH and nitrogen content of sediments may play a key role in controlling the amount of heavy metal bioavailability, further inducing a higher potential ecological risk.

Mobility and potential risk of sediment-associated heavy metal fractions under continuous drought-rewetting cycles

Ecological decline in the water level fluctuating (WLF) zone of the Three Gorges Reservoir (TGR) has been well established over the past decades. However, the effect of heavy metal fractions present in the sediment and their potential ecological risk under the anti-seasonal hydrological regime are still unclear. The Pengxi River is a tributary of the Yangtze River and it has a typical annual water level fluctuation ranging from 145 to 175m above sea level. The current study examined heavy metal fractions in sediments containing Cr, Cd, Cu, Pb and Mn collected along the WLF zone using the Tessier sequential extraction scheme. The total organic carbon (TC), total nitrogen (TN), carbon/nitrogen ratio (C/N), pH, particle size composition and content of nitrate (NO3--N), and ammonium (NH4+-N) differed dramatically among the sampled altitudes and depths and was significantly correlated with the flooding time of the WLF zone. At lower altitudes of the WLF zone, the amounts of the exchangeable (EXC), carbonate-bound (CA) and total heavy metal contents of the surface sediment were much higher compared to those of higher altitudes of the WLF zone. The risk assessment code (RAC) for Cd and Mn showed an opposite trend to that of Cr, Cu, and Pb and mainly depended on the organic matter-bound fraction (OM). The modified RAC (mRAC) indicated a very high potential adverse effect for the whole WLF zone, although the risk value was much lower at the lower altitudes and upper depths of the WLF zone. Our results showed that the positive response of the loosely bound fractions (LOS) of heavy metals to the drought-rewetting (DRW) process minimizes the risk of heavy metals in the WLF zone sediment.

SYNTHESIS, CRYSTAL STRUCTURES, AND ANTIBACTERIAL ACTIVITY OF A SERIES OF HYDRAZONE COMPOUNDS DERIVED FROM 4-METHYLBENZOHYDRAZIDE

ABSTRACT A series of hydrazone compounds, 4-methyl- N’ -(4-nitrobenzylidene)benzohydrazide methanol solvate ( 1 ), N’ -(4-hydroxy-3-nitrobenzylidene)-4-methylbenzohydrazide dimethanol solvate ( 2 ), and N’ -(3,5-dibromobenzylidene)-4-methylbenzohydrazide ( 3 ), derived from 4-methylbenzohydrazide with different benzaldehydes, were synthesized and characterized by physico-chemical methods and single crystal X-ray diffraction. Crystals of the compounds are stabilized by intermolecular hydrogen bonds, as well as π···π stacking interactions. Antibacterial activity of the compounds against Staphylococcus aureus , Escherichia coli , and Klebsielle pneumoniae strains was studied. Compounds 1 and 2 have moderate minimum inhibition concentration values on the tested bacteria strains. Compound 3 , with the Br-substituent groups, showed the highest activity on the bacterial strains. Keywords: Synthesis; crystal structure; hydrazone compound; hydrogen bonding; antibacterial activity. 1 INTRODUCTION

QSPR Study on n-Octanol/Water Partition Coefficient of PCDD/Fs by Three-Dimensional Holographic Vector of Atomic Interaction Field

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a group of important persistent organic pollutants. Quantitative structure–property relationship (QSPR) modeling is a powerful approach for predicting the properties of environmental organic pollutants from their structure descriptors. In this study, a QSPR model is established for estimating n-octanol/water partition coefficient (log KOW) of PCDD/Fs. Three-dimensional holographic vector of atomic interaction field (3D-HoVAIF) is used to describe the chemical structures, SMR-PLS QSAR model has been created and good correlation coefficients and cross-validated correlation coefficient is obtained. Predictive capability of the models has also been demonstrated by leave-one-out cross-validation. Moreover, the estimated values have been presented for those PCDD/Fs which are lack of experimentally data by the optimum model.

Chemical Characteristics of Precipitation in a Typical Urban Site of the Hinterland in Three Gorges Reservoir, China

Major water-soluble ions were analyzed for two-year precipitation samples in Wanzhou, a typical urban site of the hinterland of Chinese Three Gorges Reservoir. The pH values of the precipitation were in the range of 4.0 to 8.3, and the volume-weighted mean (VWM) value was 5.0. The concentration order of anions and cations was as follows: and , respectively. Good correlations were found between and , and Ca2

Synthesis and structures of two hydrazone compounds derived from 4-methylbenzohydrazide

Two hydrazone compounds N′-(2,4-dichlorobenzylidene)-4-methylbenzohydrazide monohydrate (1) and 2-chloro-5-nitro-N′-(4-methylbenzylidene)benzohydrazide (2) derived from 4-methylbenzohydrazide with different benzaldehydes are synthesized and characterized by physicochemical methods and single crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 4.714(2) Å, b = 13.093(3) Å, c = 24.754(3) Å, V = 1527.9(8) Å3, Z = 4, R1 = 0.0812, and wR2 = 0.1623. Compound 2 crystallizes in the monoclinic space group Cc with unit cell parameters a = 11.564(2) Å, b = 13.271(2) Å, c = 9.462(2) Å, β = 96.860(2)°, V = 1441.7(4) Å3, Z = 4, R1 = 0.0461, and wR2 = 0.0896. The crystals of the compounds are stabilized by intermolecular hydrogen bonds as well as π…π stacking interactions.

Effects of DOM on the Migration of Cr (VI) in Soils

Dissolved organic matter is an important and active component in both terrestrial and aquatic ecosystem. It has become a hotspot in environment science, with active functional groups such as carboxyl, hydroxyl, amino that can influence adsorption and migration of heavy metal contaminants in soil system. Through soil column leaching experiment the article demonstrates that Cr (VI) is dominated by physical adsorption in soils. By using DOM eluent and distilled water to leach at different temperatures in soil, this article shows that release ability of Cr increases with temperature rising, while its deposition capacity increases with temperature decreasing in Water Level Fluctuating Zone. Combined with Gibbs theory, Cr (VI) may take complexation reaction with DOM in soil medium. Thus, new substances appear under the proof of XRD graph.

Estimation of the physicochemical properties of PCDD/Fs using three-dimensional holographic vector of atomic interaction field

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a group of important persistent organic pollutants. In the present study, the three-dimensional holographic vector of atomic interaction field (3D-HoVAIF) method is used to describe the chemical structures of PCDD/Fs. After variable screening using a stepwise multiple regression (SMR) technique, the linear relationships among six physicochemical properties of PCDD/Fs and 3D-HoVAIF descriptors are built using a partial least-squares (PLS) regression model. The results show that the 3D-HoVAIF descriptors can be used to express the quantitative structure–property relationships of PCDD/Fs. The predictive capabilities of the models have also been confirmed by leave-one-out cross-validation. The optimum model has been used to estimate values for PCDD/Fs for which no experimental data on physicochemical properties are available. Supplemental materials are available for this article. Go to the publishers online edition of Journal of Environmental Science and Health: Part A to view the free supplemental file.