Dam construction alters natural flow regimes which,in turn,cause significant changes in fish communities during and after impoundment. The construction of the Three Gorges Reservoir,from impoundment of the Changjiang(...Dam construction alters natural flow regimes which,in turn,cause significant changes in fish communities during and after impoundment. The construction of the Three Gorges Reservoir,from impoundment of the Changjiang(Yangtze) River,China,may have affected native fish species. Thus,the status of two lotic freshwater fish species,Coreius heterodon and C.guichenoti,were monitored in the Three Gorges Reservoir,including fish abundance,individual composition,growth,condition,and mortality. Data on both species were gathered from upstream,midstream and downstream areas of the reservoir and,where available,from studies published before and after dam construction. Lower abundance,slower growth,a less diversified age structure,poorer fish condition(indicated by hepatosomatic index) and higher mortalities were recorded in sites nearest the dam compared with upstream areas. Furthermore,after final impoundment,individual Coreius species inhabiting the area changed,with young individuals becoming more abundant,while upstream of the reservoir the two Coreius species became smaller at a given age. The results show that the status of the two Coreius species was subject to dramatic changes after impoundment.展开更多
Recovery of copper ions from wastewater using a hollow fiber supported emulsion liquid membrane (HFSELM) was studied with LIX984N as carrier, kerosene as diluents, and sulfuric acid solution as stripping phase. Effect...Recovery of copper ions from wastewater using a hollow fiber supported emulsion liquid membrane (HFSELM) was studied with LIX984N as carrier, kerosene as diluents, and sulfuric acid solution as stripping phase. Effects of compositions of feed and emulsion liquid phase, flow rates on both sides of membrane, and hollow fiber module parameters were investigated. The stability of the emulsion liquid phase without surfactant and the effect of buffer in the feed phase on the extraction rate were also evaluated. It is found that the stability of the emulsion phase without surfactant is poor. Higher flow velocity gives shorter residence time for the emulsion liquid phase on the tube side, reducing the effect of particle coalescence on the separation process. The extraction rate increases with the increase of feed phase pH, carrier concentration, hydrogen ion concentration in the stripping phase, and ef- fective hollow fiber area. The phase ratio in the emulsion liquid phase has a negative effect on extraction rate. The flow rates on both sides have little influence on the extraction performance of the HFSELM, while buffer addition in the feed solution improves the extraction efficiency.展开更多
The engineering geology and hydrogeology in the southern slope of Chengmenshan copper mine are very complicated,because there is a soft-weak layer between two kinds of sandstones.Field investigations demonstrate that ...The engineering geology and hydrogeology in the southern slope of Chengmenshan copper mine are very complicated,because there is a soft-weak layer between two kinds of sandstones.Field investigations demonstrate that some instability problems might occur in the slope.In this research,the southern slope,which is divided into six sections(I-0,I-1,I-2,II-0,II-1 and II-2),is selected for slope stability analysis using limit equilibrium and numerical method.Stability results show that the values of factor of safety(FOS) of sections I-0,I-1 and I-2 are very low and slope failure is likely to happen.Therefore reinforcement subjected to seismic,water and weak layer according to sections were carried out to increase the factor of safety of the three sections,two methods were used;grouting with hydration of cement and water to increase the cohesion(c) and pre-stressed anchor.Results of reinforcement showed that factor of safety increased more than 1.15.展开更多
The Taihu Lake region in East China has become prone to soil acidification, which changes heavy metals such as copper(Cu) in soil into water-soluble species and increases the mobility and contamination risks of heavy ...The Taihu Lake region in East China has become prone to soil acidification, which changes heavy metals such as copper(Cu) in soil into water-soluble species and increases the mobility and contamination risks of heavy metals in the biological environment. In this study, the kinetics of Cu2+sorption by the bulk soil and the aggregate size fractions of an acidic paddy soil collected from the Taihu Lake region, the effects of temperature on Cu2+sorption, and the p H changes of the solution were investigated by static sorption and magnetic stirring. The aggregate size fractions were prepared by low-energy ultrasonic dispersing and freeze-drying. The total sorption amounts of the bulk soil and the aggregate size fractions for Cu2+followed a descending order of clay > coarse sand > bulk soil > silt> sand, corresponding to those of organic matter content, free iron oxide content, free aluminum oxide content, and cation exchange capacity. The kinetic sorption curves of Cu2+by the bulk soil and the aggregates, which were divided into two stages(rapid and slow sequentially), were well fitted by the first-order equation, the diffusion equation, and the Elovich equation, showing significant correlations(P < 0.05). Specific and non-specific sorption dominated in the fast and slow stages, respectively, and the former was predominant throughout the sorption process. The specific sorption accelerated and the non-specific sorption decelerated with rising temperature. The p H of the solution decreased significantly during the specific sorption and remained unchanged or increased slightly during the non-specific sorption. When the specific sorption terminated, the p H of the solution was minimized nearly simultaneously.The sorption progress of Cu2+by the bulk soil significantly preceded that by the aggregates. Therefore, heavy metal contamination may be another factor reducing soil p H and metal sorption forms should be taken into consideration in studies of mitigating soil heavy metal pollution or determining environmental capacity of heavy metal in soil.展开更多
基金Supported by the National Key Technology Research and Development Program of China(No.2012BAD25B08)the China Three Gorges Corporation Project(No.CT-12-08-01)the State Key Laboratory of Freshwater Ecology and Biotechnology(No.2014FBZ04)
文摘Dam construction alters natural flow regimes which,in turn,cause significant changes in fish communities during and after impoundment. The construction of the Three Gorges Reservoir,from impoundment of the Changjiang(Yangtze) River,China,may have affected native fish species. Thus,the status of two lotic freshwater fish species,Coreius heterodon and C.guichenoti,were monitored in the Three Gorges Reservoir,including fish abundance,individual composition,growth,condition,and mortality. Data on both species were gathered from upstream,midstream and downstream areas of the reservoir and,where available,from studies published before and after dam construction. Lower abundance,slower growth,a less diversified age structure,poorer fish condition(indicated by hepatosomatic index) and higher mortalities were recorded in sites nearest the dam compared with upstream areas. Furthermore,after final impoundment,individual Coreius species inhabiting the area changed,with young individuals becoming more abundant,while upstream of the reservoir the two Coreius species became smaller at a given age. The results show that the status of the two Coreius species was subject to dramatic changes after impoundment.
基金Supported by the National Natural Science Foundation of China （20676023）
文摘Recovery of copper ions from wastewater using a hollow fiber supported emulsion liquid membrane (HFSELM) was studied with LIX984N as carrier, kerosene as diluents, and sulfuric acid solution as stripping phase. Effects of compositions of feed and emulsion liquid phase, flow rates on both sides of membrane, and hollow fiber module parameters were investigated. The stability of the emulsion liquid phase without surfactant and the effect of buffer in the feed phase on the extraction rate were also evaluated. It is found that the stability of the emulsion phase without surfactant is poor. Higher flow velocity gives shorter residence time for the emulsion liquid phase on the tube side, reducing the effect of particle coalescence on the separation process. The extraction rate increases with the increase of feed phase pH, carrier concentration, hydrogen ion concentration in the stripping phase, and ef- fective hollow fiber area. The phase ratio in the emulsion liquid phase has a negative effect on extraction rate. The flow rates on both sides have little influence on the extraction performance of the HFSELM, while buffer addition in the feed solution improves the extraction efficiency.
基金support of Jiangxi Copper Company Limited (Chengmenshan Copper Mine)China Nerin Engineering Co.,Ltd.supported by the National Natural Science Foundation of China (No.11372363)
文摘The engineering geology and hydrogeology in the southern slope of Chengmenshan copper mine are very complicated,because there is a soft-weak layer between two kinds of sandstones.Field investigations demonstrate that some instability problems might occur in the slope.In this research,the southern slope,which is divided into six sections(I-0,I-1,I-2,II-0,II-1 and II-2),is selected for slope stability analysis using limit equilibrium and numerical method.Stability results show that the values of factor of safety(FOS) of sections I-0,I-1 and I-2 are very low and slope failure is likely to happen.Therefore reinforcement subjected to seismic,water and weak layer according to sections were carried out to increase the factor of safety of the three sections,two methods were used;grouting with hydration of cement and water to increase the cohesion(c) and pre-stressed anchor.Results of reinforcement showed that factor of safety increased more than 1.15.
基金the Science and Technology Support Project of Jiangsu Province(Project No.BE2013711)for financially supporting this study
文摘The Taihu Lake region in East China has become prone to soil acidification, which changes heavy metals such as copper(Cu) in soil into water-soluble species and increases the mobility and contamination risks of heavy metals in the biological environment. In this study, the kinetics of Cu2+sorption by the bulk soil and the aggregate size fractions of an acidic paddy soil collected from the Taihu Lake region, the effects of temperature on Cu2+sorption, and the p H changes of the solution were investigated by static sorption and magnetic stirring. The aggregate size fractions were prepared by low-energy ultrasonic dispersing and freeze-drying. The total sorption amounts of the bulk soil and the aggregate size fractions for Cu2+followed a descending order of clay > coarse sand > bulk soil > silt> sand, corresponding to those of organic matter content, free iron oxide content, free aluminum oxide content, and cation exchange capacity. The kinetic sorption curves of Cu2+by the bulk soil and the aggregates, which were divided into two stages(rapid and slow sequentially), were well fitted by the first-order equation, the diffusion equation, and the Elovich equation, showing significant correlations(P < 0.05). Specific and non-specific sorption dominated in the fast and slow stages, respectively, and the former was predominant throughout the sorption process. The specific sorption accelerated and the non-specific sorption decelerated with rising temperature. The p H of the solution decreased significantly during the specific sorption and remained unchanged or increased slightly during the non-specific sorption. When the specific sorption terminated, the p H of the solution was minimized nearly simultaneously.The sorption progress of Cu2+by the bulk soil significantly preceded that by the aggregates. Therefore, heavy metal contamination may be another factor reducing soil p H and metal sorption forms should be taken into consideration in studies of mitigating soil heavy metal pollution or determining environmental capacity of heavy metal in soil.
