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Zhao Z.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Xia L.,Nanjing Institute of Industry Technology | Wang F.,CAS Nanjing Institute of Soil Science | Jiang X.,CAS Nanjing Institute of Soil Science | Gao Y.,Nanjing Agricultural University
Environmental Monitoring and Assessment | Year: 2012

In this study, we screened for an economic, rapid, and efficient hypotoxic pretreatment method for organochlorine pesticides in soil samples for gas chromatography (GC) analysis. The analytical extraction efficiencies of 11 different extractants, nine types of solid-phase purification (SPP) cartridge packings, and three types of eluents for 13 organochlorine pesticides (OCPs) in spiked and natural Chinese red soil (Hydragric Acrisols) were evaluated using an ultrasonic extraction and solid-phase purification method. High percent recoveries (85-106%) were obtained for the 13 organochlorine pesticides in soil when petroleum ether/acetone/water (10:5:2, v/v) was used an extractant. They were purified using celite SPP cartridge packing and eluted with 9 mL of dichloromethane/petroleum ether (1:9, v/v). The OCPs purification pretreatment of Hydragric Acrisols, using the above method, meets the GC analysis requirements. Compared with other traditional pretreatment methods for OCPs in soil samples, this method has several advantages, such as a short extraction time, reducing the amount of solvent, having no emulsion phenomenon, and hypotoxicity to the laboratory technicians. The concentrations of 1,1,1,-trichloro-2(p-chlorophenyl)-2-(o-chlorophenyl) ethane (DDTs; 3.42-8.08 ng g -1) in field soils were higher than the hexachlorocyclohexane concentration (2.94-6.12 ng g -1). The 1,1-dichloro-2,2-bis(p- chlorophenyl) ethylene (p,p′-DDE)+1, 1-dichloro-2,2-bis(p-chlorophenyl)- ethane (p,p′-DDD)/p,p'-DDT ratio in this field soil was approximately 2.7, suggesting that no new DDT pollution source was introduced into the sampling site. © Springer Science+Business Media B.V. 2011. Source


Zhao Z.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Zhao Z.,Hohai University | Jiang Y.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Mi T.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | And 3 more authors.
Communications in Soil Science and Plant Analysis | Year: 2012

The adsorption and specific activities of acid phosphatase on soil colloids and minerals in oxalate systems with different pH values were studied using the batch method. Results indicated that the amount of phosphatase adsorption decreased in the following order: goethite ≫ yellow-brown soil (YBS) > kaolinite > latosol, and the specific activities of immobilized phosphatase were goethite > latosol > kaolinite > YBS. The profiles of enzymatic adsorption and specific activity on soil minerals were bell shaped, and their change tendencies were out of sync. The optimal pH for phosphatase adsorption was located between the isoelectric point of phosphatase and the zero point of charge of the studied soil minerals, and the optimal pH for the specific activity of the immobilized enzyme either did not change or shifted toward alkalinity. Enzymatic adsorption amounts and specific activities were greater when the enzyme was added before oxalate than when enzyme was added after oxalate. © 2012 Copyright Taylor and Francis Group, LLC. Source


Zhu Z.F.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Zhu Z.F.,Hohai University | Zhu J.Z.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Zhu J.Z.,Hohai University | Wang C.Y.,Yancheng Environmental Monitoring Center
Advanced Materials Research | Year: 2013

Recently, using biological ceramsite to treat wastewater has received wide attention. In this study, use of fly ash, cement, calcium oxide, gypsum, expanded perlite as main components, magnetic powder and sodium bicarbonate as complex additive and sodium silicate solution as binder, a novel biological ceramsite was developed by steam curing method. Density, piled density, apparent density and void fraction of the biological ceramsite were tested. The optimal percentage of main components was obtained through the orthogonal experiments. In addition, the main affecting factors were also analyzed on the properties of the biological ceramsite. The results showed that the optimal percentage of magnetic powder, sodium bicarbonate, cement and expanded perlite was 10%, 10%, 10% and 5% respectively.The analysis of the results disclosed that the affecting factors of the density, the piled density, the apparent density and the void fraction were the expanded perlite, magnetic powder, cement (and magnetic powder), sodium bicarbonate, respectively. © (2014) Trans Tech Publications, Switzerland. Source


Zhao Z.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Zhao Z.,CAS Nanjing Institute of Soil Science | Zhao Z.,Hohai University | Jiang Y.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | And 7 more authors.
Environmental Science and Pollution Research | Year: 2014

The distribution and interactions of phytoplankton and 14 polychlorinated biphenyls (PCBs) were investigated using canonical correspondence analysis in autumn in the Qinhuai River, Nanjing, China. Concentrations of PCBs in water and algal samples ranged from 33.78 to 144.84 ng/L and from 0.21 to 19.66 ng/L (0.06 to 3.04 ng/mg biomass), respectively. The predominant residual species of PCBs in water samples were tri- through hexachlorobiphenyls, and the predominant residuals in algae were tri-, tetra-, and heptachlorobiphenyls. The degree of eutrophication affected phytoplankton composition and PCB bioaccumulation, and led to sample site- and algal species specificity of PCB residues in the study area. Chlorophyta, Bacillariophyta, and Euglenophyta had strong capacities to take up PCBs, whereas Cyanophyta was less involved in the transfer of these compounds. Bioaccumulation of PCBs by algae may be affected by water quality, chlorination, phytoplankton composition, and the structure of the PCBs and the algal cell walls. © 2013 Springer-Verlag Berlin Heidelberg. Source


Chen G.H.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Chen G.H.,Hohai University | Zhu J.Z.,Key Laboratory for Integrated Regulation and Resources Exploitation on Shallow Lakes | Zhu J.Z.,Hohai University
Applied Mechanics and Materials | Year: 2013

The solidification method is a significant and resultful method for the disposal of dredged sediment. Solidified agents can be employed to improve the unconfined compressive strength (UCS) of sediment solidification. In this work, considering of economy and practicability, three kinds of optimized compound additives are selected and investigated on the effects of UCS of sediment solidification. 7d., 14d.and 28d. solidification stadium were taken to test the UCS of samples. Results showed that the activator had the best effect on increasing the UCS. The comparative tests also indicated that adding any kind of additive into the cement-based materials could improve the UCS of sediment solidification, the highest value of UCS was 11.02MPa (SCAHR). By means of scan electron microscope (SEM) technology, the microstructure images of the raw sample and solidified sample were obtained, which help to understand the development of UCS of the solidified sediments. © (2013) Trans Tech Publications, Switzerland. Source

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