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Li H.,Qingdao Agricultural University | Li H.,China Agricultural University | Wang C.,China Agricultural University | Li X.,China Agricultural University | Xiang D.,CAS Research Center for Eco Environmental Sciences
Biology and Fertility of Soils | Year: 2013

Earthworms and arbuscular mycorrhizal fungi (AMF) are important macrofauna and microorganisms of the rhizosphere. The effect of the inoculation of soil with earthworms (Aporrectodea trapezoides) and mycorrhiza (Rhizophagus intraradices) on the community structure of mycorrhizal fungi and plant nutrient uptake was determined with split plots in a maize field. Maize plants were inoculated or not inoculated with AMF, each treated with or without earthworms. Wheat straw was added as a feed source for earthworms. Inoculating AMF significantly increased maize yield (p < 0.05), and the yield was further enhanced by the addition of earthworms. Alkaline phosphomonoesterase activities, soil microbial biomass carbon (SMBC) and nitrogen (SMBN) increased with the addition of both earthworms and AMF. Soil inorganic N and available K were positively affected by earthworms, while available P showed a negative relationship with AMF. Treatment with both AMF and earthworms increased shoot and root biomass as well as their N and P uptake by affecting soil phosphomonoesterase and urease activities, SMBC, SMBN, and the content of available nutrients in soil. The applied fungal inoculants were successfully traced by polymerase chain reaction with novel primers (AML1 and AML2) which target the small subunit rRNA gene. The amplicons were classified by restriction fragment length polymorphism and sequencing. Moreover, field inoculation with inocula of non-native isolates of R. intraradices appeared to have stimulated root colonization and yield of maize. Adding earthworms might influence native AMF community, and the corresponding abundance increased after earthworms were inoculated, which has positive effects on maize growth. © 2013 Springer-Verlag Berlin Heidelberg.

Zhang X.,Fujian Normal University | Lin Y.-m.,Fujian Normal University | Shan X.-q.,CAS Research Center for Eco Environmental Sciences | Chen Z.-l.,Fujian Normal University
Chemical Engineering Journal | Year: 2010

The degradation of 2,4,6-trinitrotoluene (TNT) in wastewater using nanoscale zero-valent iron (nZVI) was investigated. The results showed that >99% TNT was degraded when the initial TNT concentration was 80 mg L-1 after degradation for 3 h by 5 g L-1 of nZVI at pH 4, 40 °C using a rotary oscillation incubator operating at 200 rpm. The Langmuir-Hinshelwood kinetics model fit the kinetics of TNT degradation by nZVI well. Fourier transform infrared (FT-IR) and ultraviolet-visible spectrophotometry showed that TNT was adsorbed on the surface of nZVI, and this reduced TNT in aqueous solution. X-ray diffraction (XRD) demonstrated that the surface of nZVI changed during the degradation of TNT. © 2010 Elsevier B.V. All rights reserved.

Li L.,Sinopec | Pan G.,CAS Research Center for Eco Environmental Sciences
Journal of Applied Phycology | Year: 2015

A new environmental friendly method was developed for cyanobacterial bloom mitigation using local lake shore soil modified by protein with high isoelectric point (pI) and chitosan jointly. Results suggested that 5 mg L−1 lysozyme- (pI ≈11) and 100 mg L−1 bromelain (pI ≈9.5)-modified 10 mg L−1 soil can both reduce the surface charge of Microcystis aeruginosa, the dominant species forming cyanobacterial blooms, from −26 to −10 mV and remove 73 and 60 % of algal cells in 30 min, respectively. The limited improvement of removal efficiency was due to the small flocs (<60 μm) formed by charge neutralization, which need more than 90 min to settle in static condition. However, when the small flocs were linked and bridged by the other modifier, chitosan with long polymer chain, large flocs of about 800 and 300 μm were formed and more than 80 % of algal cells were removed in 5 and 30 min by lysozyme-chitosan-modified soil and bromelain-chitosan-modified soil, respectively. The lower removal ability of bromelain-modified soil was due to the lower charge density leading to less powerful in destabilization of algal cells. Depending on the bicomponent modification mechanism including charge neutralization of proteins with high pI and netting and bridging function of chitosan with long polymer chain, it is possible to flocculate cyanobacterial blooms in natural waters effectively using locally available materials. © 2015 Springer Science+Business Media Dordrecht

Yan M.,Peking University | Wang D.,CAS Research Center for Eco Environmental Sciences | Korshin G.V.,University of Washington | Benedetti M.F.,University Paris Diderot
Water Research | Year: 2013

This study introduces the concept of consistent examination of changes of log-transformed absorbance spectra of dissolved organic matter (DOM) at incrementally increasing concentrations of heavy metal cations such as copper, cadmium, and aluminum at environmentally relevant concentrations. The approach is designed to highlight contributions of low-intensity absorbance features that appear to be especially sensitive to DOM reactions. In accord with this approach, log-transformed absorbance spectra of fractions of DOM from the Suwannee River were acquired at varying pHs and concentrations of copper, cadmium, and aluminum. These log-transformed spectra were processed using the differential approach and used to examine the nature of the observed changes of DOM absorbance and correlate them with the extent of Me-DOM complexation. Two alternative parameters, namely the change of the spectral slope in the range of wavelengths 325-375 nm (DSlope325-375) and differential logarithm of DOM absorbance at 350 nm (DLnA350) were introduced to quantify Cu(II), Cd(II), and Al(III) binding onto DOMs. DLnA350 and DSlope325-375 datasets were compared with the amount of DOM-bound Cu(II), Cd(II), and Al(III) estimated based on NICA-Donnan model calculations. This examination showed that the DLnA350 and DSlope325-375 acquired at various pH values, metal ions concentrations, and DOM types were strongly and unambiguously correlated with the concentration of DOM-bound metal ions. The obtained experimental results and their interpretation indicate that the introduced DSlope325-375 and DLnA35 parameters are predictive of and can be used to quantify in situ metal ions interactions with DOMs. The presented approach can be used to gain more information about DOM-metal interactions and for further optimization of existing formal models of metal-DOM complexation. © 2013 Elsevier Ltd.

Li B.,Tsinghua University | Qiu Y.,Tsinghua University | Glidle A.,University of Glasgow | McIlvenna D.,University of Glasgow | And 4 more authors.
Analytical Chemistry | Year: 2014

Bacterial growth inhibition tests have become a standard measure of the adverse effects of inhibitors for a wide range of applications, such as toxicity testing in the medical and environmental sciences. However, conventional well-plate formats for these tests are laborious and provide limited information (often being restricted to an end-point assay). In this study, we have developed a microfluidic system that enables fast quantification of the effect of an inhibitor on bacteria growth and survival, within a single experiment. This format offers a unique combination of advantages, including long-term continuous flow culture, generation of concentration gradients, and single cell morphology tracking. Using Escherichia coli and the inhibitor amoxicillin as one model system, we show excellent agreement between an on-chip single cell-based assay and conventional methods to obtain quantitative measures of antibiotic inhibition (for example, minimum inhibition concentration). Furthermore, we show that our methods can provide additional information, over and above that of the standard well-plate assay, including kinetic information on growth inhibition and measurements of bacterial morphological dynamics over a wide range of inhibitor concentrations. Finally, using a second model system, we show that this chip-based systems does not require the bacteria to be labeled and is well suited for the study of naturally occurring species. We illustrate this using Nitrosomonas europaea, an environmentally important bacteria, and show that the chip system can lead to a significant reduction in the period required for growth and inhibition measurements (<4 days, compared to weeks in a culture flask). © 2014 American Chemical Society.

Feng X.M.,CAS Research Center for Eco Environmental Sciences | Zhao Y.S.,University of Chinese Academy of Sciences
Ecological Indicators | Year: 2011

Steppe, an important belt to protect North China from dust storms, is vulnerable and has been degraded in recent decades because of climatic change and heavy grazing. In order to improve steppe management, this study presents a framework for the monitoring of grazing intensity in Xilingol steppe of middle Inner Mongolia, northern China, by integrating the CENTURY ecosystem model-based simulation and remotely sensed MODIS data-based inversion. The CENTURY model worked well after calibrations using field data 1991-1995 of Xilinhaote and Zhenglan Banner observation stations (the correlation coefficient between simulated and observed above ground biomass (AGB) is 0.85). In order to run CENTURY spatially, regional input were formulated including data such as temperature, precipitation, AGB and soil water content (SWC) at the beginning of growing season in 2002, vegetation cover and land use. The modeled AGB at the end of the growing season in 2002 was compared with that inverted from MODIS data. The spatial variation of grazing in the research area was estimated with an iterative adjusting method. Results showed that grazing is variable throughout the study area. Grazing intensity is high and concentrated in the southwest and middle of Abarger Banner, and is low and extensive on the south of Xilinhaote, west of West Ujumchin Banner and northwest of Keshiketeng Banner. This result is comparable with the field conditions. From this work, it can be concluded that human activities such as livestock grazing can be monitored at broad scales with the integration of ecosystem modeling and remote sensing approaches. © 2009 Elsevier Ltd.

Zhan A.,CAS Research Center for Eco Environmental Sciences | Zhan A.,University of Windsor | Bailey S.A.,Canadian Department of Fisheries and Oceans | Heath D.D.,University of Windsor | Macisaac H.J.,University of Windsor
Molecular Ecology Resources | Year: 2014

Metabarcode surveys of DNA extracted from environmental samples are increasingly popular for biodiversity assessment in natural communities. Such surveys rely heavily on robust genetic markers. Therefore, analysis of PCR efficiency and subsequent biodiversity estimation for different types of genetic markers and their corresponding primers is important. Here, we test the PCR efficiency and biodiversity recovery potential of three commonly used genetic markers - nuclear small subunit ribosomal DNA (18S), mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (mt16S) - using 454 pyrosequencing of a zooplankton community collected from Hamilton Harbour, Ontario. We found that biodiversity detection power and PCR efficiency varied widely among these markers. All tested primers for COI failed to provide high-quality PCR products for pyrosequencing, but newly designed primers for 18S and 16S passed all tests. Furthermore, multiple analyses based on large-scale pyrosequencing (i.e. 1/2 PicoTiter plate for each marker) showed that primers for 18S recover more (38 orders) groups than 16S (10 orders) across all taxa, and four vs. two orders and nine vs. six families for Crustacea. Our results showed that 18S, using newly designed primers, is an efficient and powerful tool for profiling biodiversity in largely unexplored communities, especially when amplification difficulties exist for mitochondrial markers such as COI. Universal primers for higher resolution markers such as COI are still needed to address the possible low resolution of 18S for species-level identification. © 2014 John Wiley & Sons Ltd.

Carlton E.J.,University of California at Berkeley | Liang S.,University of Florida | McDowell J.Z.,Emory University | Li H.,U.S. Center for Disease Control and Prevention | And 2 more authors.
Bulletin of the World Health Organization | Year: 2012

Objective To estimate the disease burden attributable to unsafe water and poor sanitation and hygiene in China, to identify high-burden groups and to inform improvement measures. Methods The disease burden attributable to unsafe water and poor sanitation and hygiene in China was estimated for diseases resulting from exposure to biologically contaminated soil and water (diarrhoeal disease, helminthiases and schistosomiasis) and vector transmission resulting from inadequate management of water resources (malaria, dengue and Japanese encephalitis). The data were obtained from China's national infectious disease reporting system, national helminthiasis surveys and national water and sanitation surveys. The fraction of each health condition attributable to unsafe water and poor sanitation and hygiene in China was estimated from data in the Chinese and international literature. Findings In 2008, 327 million people in China lacked access to piped drinking water and 535 million lacked access to improved sanitation. The same year, unsafe water and poor sanitation and hygiene accounted for 2.81 million disability-adjusted life years (DALYs) and 62 800 deaths in the country, and 83% of the attributable burden was found in children less than 5 years old. Per capita DALYs increased along an east-west gradient, with the highest burden in inland provinces having the lowest income per capita. Conclusion Despite remarkable progress, China still needs to conduct infrastructural improvement projects targeting provinces that have experienced slower economic development. Improved monitoring, increased regulatory oversight and more government transparency are needed to better estimate the effects of microbiologically and chemically contaminated water and poor sanitation and hygiene on human health.

Yang X.,Florida State University | Chen L.,CAS Research Center for Eco Environmental Sciences
International Journal of Applied Earth Observation and Geoinformation | Year: 2010

Landslides are a major type of geohazards claiming thousands of casualties and billions of dollars in property damages every year. Catastrophic landslide activities are often triggered by some extreme events such as earthquakes, excessive precipitations, or volcanic eruptions. Quickly identifying the spatial distribution of landslides induced by these extreme events is crucial for coordinating rescue efforts and planning in situ investigations. In this study, we propose an automated method for detecting the spatial distribution of earthquake-triggered landslides by examining after-event vegetation changes. Central to this method is the use of pre- and post-event remote sensor images covering the same area. Geometric correction and radiometric normalization are performed before deriving a vegetation index from each image. Then, an image differencing procedure is applied to the two derived indices. With the resultant difference image, an initial landslide distribution map is generated by highlighting the pixels with a threshold percentage decrease in the brightness values as a direct result of the image subtraction. The threshold percentage value is interactively determined by using a visual interpretation method. The final landslide distribution map is produced after using a modal filter to suppress boundary errors in the initial map. This method has been implemented in a test site, approximately 30 km from the epicenter of the Sichuan earthquake (7.9. Ms) that struck on 12 May 2008. A pre-event Thematic Mapper image and a post-event Advanced Spaceborne Thermal Emission and Reflection Radiometer scene are used. The thematic accuracy assessment indicates that 90% of the landslides have correctly been mapped. Given the relatively simple procedures and the good mapping accuracy, the image processing and change detection method identified in this study seems to be promising from an operational perspective. © 2010 Elsevier B.V.

Tuanmu M.-N.,Michigan State University | Vina A.,Michigan State University | Roloff G.J.,Michigan State University | Liu W.,Michigan State University | And 3 more authors.
Journal of Biogeography | Year: 2011

Aim Temporal transferability is an important issue when habitat models are used beyond the time frame corresponding to model development, but has not received enough attention, particularly in the context of habitat monitoring. While the combination of remote sensing technology and habitat modelling provides a useful tool for habitat monitoring, the effect of incorporating remotely sensed data on model transferability is unclear. Therefore, our objectives were to assess how different satellite-derived variables affect temporal transferability of habitat models and their usefulness for habitat monitoring. Location Wolong Nature Reserve, Sichuan Province, China. Methods We modelled giant panda habitat with the maximum entropy algorithm using panda presence data collected in two time periods and four different sets of predictor variables representing land surface phenology. Each predictor variable set contained either a time series of smoothed wide dynamic range vegetation index (WDRVI) or 11 phenology metrics, both derived from single-year or multi-year (i.e. 3-year) remotely sensed imagery acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS). We evaluated the ability of models obtained with these four variable sets to predict giant panda habitat within and across time periods by using threshold-independent and threshold-dependent evaluation methods and five indices of temporal transferability. Results Our results showed that models developed with the four variable sets were all useful for characterizing and monitoring giant panda habitat. However, the models developed using multi-year data exhibited significantly higher temporal transferability than those developed using single-year data. In addition, models developed with phenology metrics, especially when using multi-year data, exhibited significantly higher temporal transferability than those developed with the time series. Main conclusions The integration of land surface phenology, captured by high temporal resolution remotely sensed imagery, with habitat modelling constitutes a suitable tool for characterizing wildlife habitat and monitoring its temporal dynamics. Using multi-year phenology metrics reduces model complexity, multicollinearity among predictor variables and variability caused by inter-annual climatic fluctuations, thereby increasing the temporal transferability of models. This study provides useful guidance for habitat monitoring through the integration of remote sensing technology and habitat modelling, which may be useful for the conservation of the giant panda and many other species. © 2011 Blackwell Publishing Ltd.

Zhang L.,Beijing University of Chemical Technology | Rong W.,Beijing University of Chemical Technology | Chen Y.,Beijing University of Chemical Technology | Lu C.,Beijing University of Chemical Technology | Zhao L.,CAS Research Center for Eco Environmental Sciences
Sensors and Actuators, B: Chemical | Year: 2014

This work developed a facile and effective sensor for the determination of acetone, the diabetic biomarker, which was based on cataluminescence (CTL) emission on the surface of layered double oxide (LDO) that is a layered nanomaterial with easy preparation and environmental friendliness. Under the optimized conditions, the linear range of the CTL intensity versus concentration of acetone was 0.1-16 mM with the detection limit of 0.02 mM (S/N = 3). The relative standard deviation (RSD) for 50 repeated measurements of 1.0 mM acetone was 3.6%. Interestingly, there was no or weak response to seven common volatile organic compounds (VOCs), including ethanol, heptanal, ethyl acetate, methanol, formaldehyde, acetic acid and toluene. Furthermore, the proposed CTL sensor was successfully used for sensing acetone in human plasma samples of diabetes patients with a satisfactory recovery. The results demonstrated that the proposed CTL sensor had a promising capability for the sensing of acetone in diabetes diagnosis. The possible CTL mechanism from the oxidation of acetone on the surface of LDO was also discussed. © 2014 Elsevier B.V.

Kong F.,Harbin Institute of Technology | Wang A.,Harbin Institute of Technology | Liang B.,Harbin Institute of Technology | Liu W.,CAS Research Center for Eco Environmental Sciences | Cheng H.,Harbin Institute of Technology
Bioresource Technology | Year: 2013

Bioelectrochemical system (BES) that removes recalcitrant pollutant out of wastewater is of special interest for practice. This study modified the configuration of BES to be a sleeve-type with compact structure. Azo dye (acid orange 7, AO7) in the outer cathode chamber performed a complete decolorization by electrons supplied from acetate oxidized with electricigens in the inner anode chamber. The AO7 decolorization efficiency (DEAO7) was enhanced to be higher than 98% from 0.14 to 2.00mM. Electrochemical impedance spectroscopy (EIS) analysis showed that the internal resistance of anode, cathode and the whole cell was 26.4, 38.3, and 64.6Ω, respectively, indicating that the modified configuration with large area and small distance between anode and cathode can result in a lower internal resistance and higher decolorization performance. This is the first study for azo dye decolorization using sleeve-type configuration with highly efficient decolorization by abiotic cathode BES. © 2013 Elsevier Ltd.

Zhou Q.,CAS Research Center for Eco Environmental Sciences
Nanoscale | Year: 2011

Polymeric nanocapsules with nanometre-thin walls offer a promising platform for controlled cellular delivery of therapeutic or diagnostic agents. Therefore, their biocompatibility is crucial for future applications in the human body. However, there is little knowledge about their interaction with biological systems. In this study, polymeric nanocapsules containing different amounts of lipids and representing different scenarios for handling and storing nanocapsules are investigated. We find that all nanocapsules in our study can enter human cells and the presence of an outer lipid shell facilitates the process. These nanocapsules do not inhibit cell proliferation at concentrations up to 200 μg mL(-1) of nanocapsules. No cellular ROS, apoptosis or cell cycle perturbation is detected at this dose. These comprehensive examinations demonstrate that polymeric nanocapsules are promising nano-carriers for cellular delivery.

Wei Y.,Tongji University | Wei Y.,Changzhou University | Chu H.-Q.,Tongji University | Dong B.-Z.,State Key Laboratory of Pollution Control and Resource Reuse | And 3 more authors.
Desalination | Year: 2011

A new PVDF-TiO2 nanowire hybrid ultrafiltration membrane was prepared via phase inversion by dispersing TiO2 nanowires in PVDF casting solutions. The characteristics of the hybrid membranes, i.e., crystal structure, thermal stability, morphology, hydrophilicity, permeation performance, and mechanical properties, were investigated. Results of X-ray diffraction (XRD), thermal gravitational analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the interaction existed between TiO2 nanowires and PVDF and the thermal stability of the hybrid membrane had been improved by the addition of TiO2 nanowires. Concurrently, dynamic contact angles indicated that the hydrophilicity of the hybrid membranes was enhanced by the addition of TiO2 nanowires. The effects of the TiO2 nanowires in the PVDF on the permeation properties, membrane strength, and antifouling performance were examined. The experimental results indicated that PVDF-TiO2 nanowire hybrid membranes exhibited significant differences in surface properties and intrinsic properties due to TiO2 nanowires addition. Most importantly, PVDF-TiO2 nanowire hybrid membrane can avoid some of the drawbacks of PVDF-TiO2 nanoparticle hybrid membrane, such as, aggregate and leak out of TiO2 nanoparticles, also declining elongation ratio. © 2011.

Ma Y.,CAS Research Center for Eco Environmental Sciences | Hashi Y.,Shimadzu Global COE for Application and Technical Development | Ji F.,Shimadzu Global COE for Application and Technical Development | Lin J.-M.,Tsinghua University
Journal of Separation Science | Year: 2010

In this study, a simple, rapid and sensitive method for the determination of five phthalates including dimethyl phthalate, diethyl phthalate, dipropyl phthalate, benzyl butyl phthalate, and dicyclohexyl phthalate in fruit jellies by LC coupled with MS has been developed. Samples were pretreated by a dispersive SPE method, termed QuEChERS, which is an acronym for quick, easy, cheap, effective, rugged, and safe. The standard calibration curves were linear for all the analytes over the concentration range of 10-250 ng/mL, and the correlation coefficients ranged from 0.9976 to 0.9991. The LODs and LOQs were in the ranges of 0.09-3.68 ng/mL and 0.28-11.25 ng/mL, respectively. The accuracy of this method was evaluated by measuring the recovery from spiked samples. The recoveries of all five phthalates from samples spiked at three different concentrations (0.01, 0.03, and 0.05 mg/kg), were in the ranges of 83.5-103.9%, 86.7-95.8%, and 87.1-95.2%, respectively. The RSD values for the samples spiked at 0.01, 0.03 , and 0.05 mg/kg ranged from 2.0-7.6%, 1.4-6.4%, and 1.2-3.8%, respectively. The method has been used for the analysis of real samples and BBP and DEP were found in real samples. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.

Colombo C.,University of Molise | Palumbo G.,University of Molise | He J.-Z.,CAS Research Center for Eco Environmental Sciences | Pinton R.,University of Udine | Cesco S.,Free University of Bozen Bolzano
Journal of Soils and Sediments | Year: 2014

Purpose: The rationale of this paper is to review the state of the art regarding the biotic and abiotic reactions that can influence Fe availability in soils. In soil, the management-induced change from oxic to anoxic environment results in temporal and spatial variations of redox reactions, which, in turn, affect the Fe dynamics and Fe mineral constituents. Measuring the Fe forms in organic complexes and the interaction between bacteria and Fe is a major challenge in getting a better quantitative understanding of the dynamics of Fe in complex soil ecosystems. Materials and methods: We review the existing literature on chemical and biochemical processes in soils related with the availability of Fe that influences plant nutrition. We describe Fe acquisition by plant and bacteria, and the different Fe-organic complexes in order to understand their relationships and the role of Fe in the soil carbon cycle. Results and discussion: Although total Fe is generally high in soil, the magnitude of its available fraction is generally very low and is governed by very low solubility of Fe oxides. Plants and microorganisms can have different strategies in order to improve Fe uptake including the release of organic molecules and metabolites able to form complexes with FeIII. Microorganisms appear to be highly competitive for Fe compared with plant roots. Crystalline Fe and poorly crystalline (hydro)oxides are also able to influence the carbon storage in soil. Conclusion: The solubility of crystalline Fe minerals in soil is usually very low; however, the interaction with plant, microbes, and organic substance can improve the formation of soluble FeIII complexes and increase the availability of Fe for plant growth. Microbes release siderophores and plant exudates (e.g., phytosiderophores, organic acids, and flavonoids), which can bind and solubilize the Fe present in minerals. The improved understanding of this topic can enable the identification of effective solutions for remedying Fe deficiency or, alternatively, restricting the onset of its symptoms and yield's limitations in crops. Therefore, development and testing of new analytical techniques and an integrated approach between soil biology and soil chemistry are important prerequisites. © 2013 Springer-Verlag Berlin Heidelberg.

Wu Y.,CAS Nanjing Institute of Geography and Limnology | Xiang Y.,CAS Nanjing Institute of Geography and Limnology | Wang J.,CAS Nanjing Institute of Geography and Limnology | Zhong J.,CAS Nanjing Institute of Geography and Limnology | And 2 more authors.
Environmental Microbiology Reports | Year: 2010

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) communities within the surface sediments of Lake Taihu, a large eutrophic freshwater lake in China, were investigated using molecular approaches targeting the ammonia monooxygenase subunit A (amoA) gene. Large intra-lake variability in the composition and the relative abundance of both groups of ammonia-oxidizing prokaryotes was observed. Archaeal amoA far outnumbered bacterial amoA at most sites except those located in the Eastern Taihu Bay. This bay, which is used for intensive pen aquaculture, harboured the most unique AOA communities but was dominated by AOB in terms of relative abundance. Accumulation of organic substances rather than presence of submersed macrophytes significantly influenced the relative abundance of AOA. In contrast, shifts in the abundance of AOB were not found to be significantly related to the investigated environmental parameters. Phylogenetic analysis showed that all archaeal amoA sequences fell within either the Crenarchaeotal Group (CG) I.1b or the CG I.1a subgroup, and all AOB clustered exclusively with the genus Nitrosomonas. These findings represent the first detailed survey of AOA in eutrophic freshwater lake sediments by demonstrating that AOA dominate the ammonia-oxidizing communities, and are negatively correlated with the accumulation of organic substances. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Iron reduction is an important biogeochemical process in paddy soils, yet little is known about the microbial coupling between nitrogen and iron reduction. Here, we investigated the shift of acetate-metabolizing iron-reducers under long-term nitrogen fertilization using 13C-acetate-based ribosomal RNA (rRNA)-stable isotope probing (SIP) and pyrosequencing in an incubation experiment, and the shift of putative iron-reducers in original field samples were investigated by 16S rRNA gene-based pyrosequencing. During SIP incubations, in the presence of iron(III) oxyhydroxides, more iron(II) formation and less methane production were detected in nitrogen-fertilized (N) compared with non-fertilized (NF) soil. In 13C-rRNA from microcosms amended with ferrihydrite (FER), Geobacter spp. were the important active iron-reducers in both soils, and labeled to a greater extent in N (31% of the bacterial classified sequences) than NF soils (11%). Pyrosequencing of the total 16S rRNA transcripts from microcosms at the whole community level further revealed hitherto unknown metabolisms of potential FER reduction by microorganisms including Pseudomonas and Solibacillus spp. in N soil, Dechloromonas, Clostridium, Bacillus and Solibacillus spp. in NF soil. Goethite (GOE) amendment stimulated Geobacter spp. to a lesser extent in both soils compared with FER treatment. Pseudomonas spp. in the N soil and Clostridium spp. in the NF soil may also be involved in GOE reduction. Pyrosequencing results from field samples showed that Geobacter spp. were the most abundant putative iron-reducers in both soils, and significantly stimulated by long-term nitrogen fertilization. Overall, for the first time, we demonstrate that long-term nitrogen fertilization promotes iron(III) reduction and modulates iron-reducing bacterial community in paddy soils.The ISME Journal advance online publication, 29 August 2014; doi:10.1038/ismej.2014.159.

Zhang M.L.,CAS Research Center for Eco Environmental Sciences
Environmental technology | Year: 2011

A bacterial strain was isolated from Lake Dianchi (China) and its degradability and degradative pathways of the cyanobacterial toxin microcystin-LR (MC-LR) were studied. On the basis of morphological, physiological and biochemical tests, the strain was identified as Ralstonia solanacearum. The acute oral toxicity tests showed that Ralstonia solanacearum belongs to a non-toxic class. This bacterium degraded MC-LR at the rate of 9.4 mg/L per day, which was higher than those of the other bacterial strains reported in the literature. As for the degradative pathways, the results showed that the Adda-Arg peptide bond of MC-LR was initially hydrolysed by Ralstonia solanacearum to form a linear molecule as an intermediate. The intermediate product subsequently underwent a cyclisation reaction via dehydration to form a final product with a small peptide ring at one end of the molecule. These biodegradative pathways were different from those reported with other bacterial strains, suggesting that MC-LR may undergo different transformations, and different products were formed due to different compositions of bacteria present in natural lakes and reservoirs. These results suggest that there is a significant potential for Ralstonia solanacearum as a degrader for MC-LR removal from wastewater.

Huang C.,National Chiao Tung University | Lin J.-L.,National Chiao Tung University | Lee W.-S.,National Chiao Tung University | Pan J.R.,National Chiao Tung University | Zhao B.,CAS Research Center for Eco Environmental Sciences
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2011

Coagulation is an effective pre-treatment process in membrane filtration for recycling spent filter backwash water (SFBW). To optimize the operation of the coagulation/filtration process for SFBW recycling, it is important to understand the critical role of coagulation mechanism on membrane filtration. In this study, SFBW samples were coagulated with polyaluminum chloride (PACl), followed by a dead-end microfiltration (MF), and the mean permeate flux and permeate quality were determined. The results showed that pre-coagulation improved the flux decline and the degree of the improvement was closely related to coagulation mechanisms. The permeate flux was enhanced most effectively by precipitation charge neutralization (PCN) coagulation, followed by charge neutralization and then sweep flocculation. Close examination of cake properties indicated that the reduced cake resistance (Rc) was subjected to the coagulated SFBW flocs in response to different coagulation mechanism. Smaller flocs, induced by PCN, were more compact and stronger, forming less compressible cake, which facilitated membrane filtration, while slower membrane filtration was observed when more compressible cake formed from larger flocs of looser and weaker structure. Coagulation mechanism also governed the size distribution of SFBW floc, which is strongly related to the subsequent cake compressibility as well as membrane permeability in membrane filtration. © 2011 Elsevier B.V.

Li Y.,Nanyang Technological University | Zhu G.,CAS Research Center for Eco Environmental Sciences | Ng W.J.,Nanyang Technological University | Ng W.J.,Nanyang Environment and Water Research Institute | Tan S.K.,Nanyang Technological University
Science of the Total Environment | Year: 2014

This paper presents a comprehensive review of the current state of research activities on the application of constructed wetlands for removing pharmaceutical contaminants from wastewater. The focus of the review was placed on the application of constructed wetlands as an alternative secondary wastewater treatment system or as a wastewater polishing treatment system. The design parameters of the reported constructed wetlands including the physical configuration, hydraulic mode, vegetation species, and targeting pharmaceuticals were summarized. The removal efficiencies of pharmaceuticals under different conditions in the wetlands were evaluated at the macroscopic level. In addition, the importance of the three main components of constructed wetlands (substrate, plants and microbes) for pharmaceutical removal was analyzed to elucidate the possible removal mechanisms involved. There is a general consensus among many researchers that constructed wetlands hold great potential of being used as an alternative secondary wastewater treatment system or as a wastewater polishing treatment system for the removal of pharmaceuticals, but relevant reported studies are scarce and are not conclusive in their findings. Current knowledge is limited on the removal efficiencies of pharmaceuticals in constructed wetlands, the removal mechanisms involved, the toxicity to constructed wetlands caused by pharmaceuticals, and the influences of certain important parameters (configuration design, hydraulic mode, temperature and seasonality, pH, oxygen and redox potential, etc.). This review promotes further research on these issues to provide more and better convincing evidences for the function and performance of larger laboratory-scale, pilot-scale or full-scale constructed wetlands. © 2013 Elsevier B.V.

Li H.,China Agricultural University | Xiang D.,CAS Research Center for Eco Environmental Sciences | Wang C.,China Agricultural University | Li X.,China Agricultural University | Lou Y.,China Agricultural University
Biology and Fertility of Soils | Year: 2012

A pot experiment was conducted to investigate the effect of epigeic earthworm (Eisenia fetida) and arbuscular mycorrhizal (AM) fungi (Glomus intraradices) on soil enzyme activities and nutrient uptake by maize, which was grown on a mixture of sterilized soil and sand. Maize plants were grown in pots inoculated or not inoculated with AMF, treated or not treated with earthworms. Wheat straw was added as a feed source for earthworms. Mycorrhizal colonization of maize was markedly increased in AM fungi inoculated pots and further increased by addition of epigeic earthworms. AM fungi and epigeic earthworms increased maize shoot and root biomass, respectively. Soil acid phosphatase activity was increased by both earthworms and mycorrhiza, while urease and cellulase activities were only affected by earthworms. Inoculation with AM fungi significantly (p < 0. 001) increased the activity of soil acid phosphatase but decreased soil available phosphorus (P) and potassium (K) concentrations at harvest. Addition of earthworms alone significantly (p < 0. 05) increased soil ammonium-N content, but decreased soil available P and K contents. AM fungi increased maize shoot weight and root P content, while earthworms improved N, P, and K contents in shoots. AM fungi and earthworm interactively increased maize shoot and root biomass through their regulation of soil enzyme activities and on the content of available soil N, P, and K. © 2012 Springer-Verlag.

Nguyen D.L.,Korea Institute of Science and Technology | Nguyen D.L.,Korean University of Science and Technology | Kim J.Y.,Korea Institute of Science and Technology | Shim S.-G.,Korea Institute of Science and Technology | And 2 more authors.
Atmospheric Environment | Year: 2011

The first ever shipboard measurements of atmospheric gaseous elemental mercury (GEM) over the Yellow Sea were carried out. Ground measurements were also performed at background and urban sites surrounding the Yellow Sea during 2007-2008. The GEM mean concentrations obtained from ground measurements at Ningbo, Chengshantou, and Deokjeok, and from shipboard measurements for the routes of Incheon-Qingdao, Incheon-Weihai, and Incheon-Jeju were 3.79 ± 1.29, 2.07 ± 0.91, 1.79 ± 0.80, 1.82 ± 0.51, 2.03 ± 0.66, and 2.43 ± 0.59 ng m-3, respectively. Compared with the GEM background concentration in the northern hemisphere, the slightly higher GEM regional background concentration of 2.08 ± 0.85 ng m-3 over the Yellow Sea region, based on shipboard measurements and ground measurements at background sites, gave implications for the impact of anthropogenic mercury sources surrounding the Yellow Sea. Shipboard measurements over the Yellow Sea showed a decrease of mercury concentration compared with aircraft measurements during ACE-ASIA campaign in 2001, though it was still generally higher than those from other seas or oceans around the world. The contrasting patterns in seasonal and diurnal variations of GEM concentration between background and urban sites were apparent due to the influence of different sources; for example, natural sources, such as vegetative and foliar emissions in background area, and local anthropogenic sources, such as coal combustion in urban area. The significantly elevated GEM concentrations at Deokjeok, a Korean background site, during the spring of 2008 were attributed to the long-range transport from the southern part of Liaoning province, one of the heaviest mercury-polluted areas in China. © 2010 Elsevier Ltd.

Hou Y.,University of Wisconsin - Milwaukee | Zhang B.,CAS Research Center for Eco Environmental Sciences | Wen Z.,University of Wisconsin - Milwaukee | Cui S.,University of Wisconsin - Milwaukee | And 3 more authors.
Journal of Materials Chemistry A | Year: 2014

Cost-effective catalysts are the key to the successful deployment of microbial electrolysis cells (MECs) for hydrogen production from organic wastes. Herein, we report a novel catalyst for hydrogen evolution in MECs based on a 3D hybrid of layered MoS2/nitrogen-doped graphene nanosheet aerogels (3D MoS2/N-GAs) that were prepared by a facile hydrothermal approach. A high output current density of 0.36 mA cm-2 with a hydrogen production rate of 0.19 m3 H2 m-3 d -1 was achieved for the hybrid at a 0.8 V bias, significantly higher than that of MoS2 nanosheets and N-GAs alone and comparable to that of the Pt/C catalyst when being applied in MECs. The outstanding performance of the hybrid benefits from its 3D conductive networks, porous structure, and strong synergic effects between MoS2 nanosheets and N-GAs, making it a promising catalyst for hydrogen production from wastewater through bio-electrochemical reactions. This journal is © the Partner Organisations 2014.

Mu Q.,Shandong University | Mu Q.,Fred Hutchinson Cancer Research Center | Mu Q.,University of Washington | Jiang G.,CAS Research Center for Eco Environmental Sciences | And 5 more authors.
Chemical Reviews | Year: 2014

A recently reported incident of severe pulmonary fibrosis caused by inhaled polymer nanoparticles in seven female workers obtained much attention. In addition to the release of ENM waste from industrial sites, a major release of ENMs to environmental water occurs due to home and personal use of appliances, cosmetics, and personal products, such as shampoo and sunscreen. Airborne and aqueous ENMs pose immediate danger to the human respiratory and gastrointestinal systems. ENMs may enter other human organs after they are absorbed into the bloodstream through the gastrointestinal and respiratory systems. Practically, a thorough understanding of the fundamental chemical interactions between nanoparticles and biological systems has two direct impacts. First, this knowledge will encourage and assist experimental approaches to chemically modify nanoparticle surfaces for various industrial or medicinal applications.

Chen B.,Beijing Normal University | Wang R.,CAS Research Center for Eco Environmental Sciences
Ecological Indicators | Year: 2014

The editorial section of the special issue of Ecological Indicators focuses on describing integrated ecological indicators for sustainable urban ecosystem evaluation and management. It probes we aim to probe into the regulation measures to optimize the configuration of water resources and realize the integration of the fundamental research innovation and the management practice, thus providing decision support for the integration of water security, ecological security and sustainable socio-economic development of cities and regions. A group of researchers introduces a new multi-layered indicator set for urban metabolism studies, which is designed to gather information on the definition, biophysical characteristics, and metabolic flows of megacities.

Zhao F.-J.,Nanjing Agricultural University | Zhao F.-J.,Rothamsted Research | Moore K.L.,University of Oxford | Lombi E.,University of South Australia | And 2 more authors.
Trends in Plant Science | Year: 2014

To maintain cellular homeostasis, concentrations, chemical speciation, and localization of mineral nutrients and toxic trace elements need to be regulated. Imaging the cellular and subcellular localization of elements and measuring their in situ chemical speciation are challenging tasks that can be undertaken using synchrotron-based techniques, such as X-ray fluorescence and X-ray absorption spectrometry, and mass spectrometry-based techniques, such as secondary ion mass spectrometry and laser-ablation inductively coupled plasma mass spectrometry. We review the advantages and limitations of these techniques, and discuss examples of their applications, which have revealed highly heterogeneous distribution patterns of elements in different cell types, often varying in chemical speciation. Combining these techniques with molecular genetic approaches can unravel functions of genes involved in element homeostasis. © 2013 Elsevier Ltd.

Pan G.,CAS Research Center for Eco Environmental Sciences | Chen J.,CAS Yantai Institute of Coastal Zone Research | Anderson D.M.,Woods Hole Oceanographic Institution
Harmful Algae | Year: 2011

A new method was developed for marine harmful algal bloom (HAB) mitigation using local beach sand or silica sand modified with chitosan and polyaluminum chloride (PAC). Untreated sand was ineffective in flocculating algal cells, but 80% removal efficiency was achieved for Amphidinium carterae Hulburt and Chlorella sp. in 3min (t80=3min) using 120mgL-1 sand modified with 10mgL-1 PAC and 10mgL-1 chitosan. After several hours 92-96% removal was achieved. The t80 for removing A. carterae using the modifiers only (PAC and chitosan combined) was 60min and for Chlorella sp. 120min, which are much slower than with the corresponding modified sand. Sands were critical for speeding up the kinetic processes of flocculation and sedimentation of algal flocs. PAC was helpful in forming small flocs and chitosan is essential to bridge the small flocs into large dense flocs. Chitosan was also important in inhibiting the escape of cells from the flocs. Chitosan and PAC used together as modifiers make it possible to use local beach sands for HAB mitigation in seawater. Economical and environmental concerns could be reduced through the use of sands and biodegradable chitosan, but the potential impacts of PAC need further study. © 2011 Elsevier B.V.

Liu Y.,Environment Canada | Liu Y.,CAS Research Center for Eco Environmental Sciences | Huang L.,Environment Canada | Li S.-M.,Environment Canada | And 2 more authors.
Atmospheric Chemistry and Physics | Year: 2014

A particle-phase relative rates technique is used to investigate the heterogeneous reaction between OH radicals and tris-2-butoxyethyl phosphate (TBEP) at 298K by combining aerosol time-of-flight mass spectrometry (C-ToFMS) data and positive matrix factor (PMF) analysis. The derived second-order rate constants (k2) for the heterogeneous loss of TBEP is (4.44 ± 0.45)× 10-12 cm3 molecule-1 s-1, from which an approximate particle-phase lifetime was estimated to be 2.6 (2.3-2.9) days. However, large differences in the rate constants for TBEP relative to a reference compound were observed when comparing internally and externally mixed TBEP/organic particles, and upon changes in the RH. The heterogeneous degradation of TBEP was found to be depressed or enhanced depending upon the particle mixing state and phase, highlighting the complexity of heterogeneous oxidation in the atmosphere. The effect of gas-particle partitioning on the estimated overall lifetime (gas + particle) for several organophosphate esters (OPEs) was also examined through the explicit modeling of this process. The overall atmospheric lifetimes of TBEP, tris-2-ethylhexyl phosphate (TEHP) and tris-1,3-dichloro-2-propyl phosphate (TDCPP) were estimated to be 1.9, 1.9 and 2.4 days respectively, and are highly dependent upon particle size. These results demonstrate that modeling the atmospheric fate of particle-phase toxic compounds for the purpose of risk assessment must include the gas-particle partitioning process, and in the future include the effect of other particulate components on the evaporation kinetics and/or the heterogeneous loss rates. © Author(s) 2014.

Zhang Y.,Chinese University of Hong Kong | Lin H.,Chinese University of Hong Kong | Chen C.,Chinese Academy of Sciences | Chen L.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Environmental Research Letters | Year: 2011

The objective of this work is to estimate chlorophyll-a (chl-a) concentration in the Pearl River estuary in China. To test the performance of algorithms for the estimation of the chl-a concentration in these productive turbid waters, the maximum band ratio (MBR) and near-infrared-red (NIR-red) models are used in this study. Specific focus is placed on (a)comparing the ability of the models to estimate chl-a in the range 1-12 mg m-3, which is typical for coastal and estuarine waters, and (b) assessing the potential of the Moderate Resolution Imaging Spectrometer (MODIS) and Medium Resolution Imaging Spectrometer (MERIS) to estimate chl-a concentrations. Reflectance spectra and water samples were collected at 13 stations with chl-a ranging from 0.83 to 11.8 mg m-3 and total suspended matter from 9.9 to 21.5 g m-3. A close relationship was found between chl-a concentration and total suspended matter concentration with the determining coefficient (R2) above 0.89. The MBR calculated in the spectral bands of MODIS proved to be a good proxy for chl-a concentration (R2 > 0.93). On the other hand, both the NIR-red three-band model, with wavebands around 665, 700, and 730nm, and the NIR-red two-band model (with bands around 665 and 700nm) explained more than 95% of the chl-a variation, and we were able to estimate chl-a concentrations with a root mean square error below 1 mg m -3. The two-and three-band NIR-red models with MERIS spectral bands accounted for 93% of the chl-a variation. These findings imply that the extensive database of MODIS and MERIS images could be used to quantitatively monitor chl-a in the Pearl River estuary. © 2011 IOP Publishing Ltd.

Zhang G.,Beijing University of Technology | Ruan Z.,Beijing University of Technology | Ji S.,Beijing University of Technology | Liu Z.,CAS Research Center for Eco Environmental Sciences
Langmuir | Year: 2010

In this article, a layer-by-layer (LbL)-assembled coordination multilayer on planar and 3D substrates was explored by the alternate deposition of a transition-metal-containing polyelectrolyte and a ligand-containing polymer via the formation of complexes. The metal-ligand coordination between the building blocks of Co2+-exchanged poly(styrene sulfonate) (PSS) and poly(4-vinyl pyridine) (P4 VP) has been demonstrated using UV-vis, FTIR, and XPS. The film thickness, structure, and morphology as well as the wettability as a function of bilayer number have been systematically investigated by profilometry, SEM, AFM, and contact angle analyzers. For the purpose of separation applications, the metal-ligand-coordinated multilayer was assembled on both flat sheet and hollow fiber polymeric porous substrates using a dynamic pressure-driven LbL technique. It was demonstrated that the LbL-assembled PSS(Co)1/2/P4 VP multilayer membrane had high dehydration performance with respect to different solvent-water mixtures; it also had aromatic compound permselectivity from aromatic-aliphatic hydrocarbons and water-softening capacity. Meanwhile, the successful assembly of multilayers on hollow fibers indicates that the dynamic pressure-driven LbL technique is a unique approach to the construction of multilayers on porous 3-D substrates. Therefore, the metal-ligand-coordinated self-assembly could emerge as a powerful technique for the preparation of a range of separation membranes in different types of modules. © 2009 American Chemical Society.

Yang M.,CAS Research Center for Eco Environmental Sciences | Zheng S.,Beijing Normal University
Biomass and Bioenergy | Year: 2014

Microbial single-cell-protein (SCP) production from high-organic-strength industrial wastewaters is considered an attractive method for both wastewater purification and resource utilization. In the last two decades, pollutant removal-oriented yeast SCP production processes, i.e., yeast treatment processes, have attracted a great deal of attention from a variety of research groups worldwide. Different from conventional SCP production processes, yeast treatment processes are characterized by higher pollutant removal rates, lower production costs, highly adaptive yeast isolates from nature, no excess nutrient supplements, and are performed under non-sterile conditions. Furthermore, yeast treatment processes are similar to bacteria-dominated conventional activated sludge processes, which offer more choices for yeast SCP production and industrial wastewater treatment. This review discusses why highly adaptive yeast species isolated from nature are used in the yeast treatment process rather than commercial SCP producers. It also describes the application of yeast treatment processes for treating high-carboxyhydrate, oil-rich and high-salinity industrial wastewater, focusing primarily on high-strength biodegradable organic substances, which usually account for the major fraction of biochemical oxygen demand. Also discussed is the biodegradation of xenobiotics, such as color (including dye and pigment) and toxic substances (including phenols, chlorophenols, polycyclic aromatic hydrocarbons, etc.), present in industrial wastewater. Based on molecular information of yeast community structures and their regulation in yeast treatment systems, we also discuss how to maintain efficient yeast species in yeast biomass and how to control bacterial and mold proliferation in yeast treatment systems. © 2014 Elsevier Ltd.

Zhang S.-M.,Beijing Institute of Radiation Medicine | Song M.,CAS Research Center for Eco Environmental Sciences | Yang T.-Y.,Beijing Institute of Radiation Medicine | Fan R.,Beijing Institute of Radiation Medicine | And 2 more authors.
Cell Cycle | Year: 2012

HIV-1 Tat triggers intrinsic and extrinsic apoptosis pathways in both infected and uninfected cells and plays an important role in the pathogenesis of AIDS. Knocking down Tip60, an interactive protein of Tat, leads to the impairment of cell cycle progression, indicating a key role of Tip60 in cell cycle control. We found that Tip60 interacts with Plk1 through its ZnF-MYST domain, and that this interaction is enhanced in the G2/M phase. In addition, cyclin B1 was confirmed to interact with the ZnF domain of Tip60. Immunofluorescence imaging showed that Tip60 co-localizes with both Plk1 and cyclin B1 at the centrosome during the mitotic phase and to the mid-body during cytokinesis. Further experiments revealed that Tip60 forms a ternary complex with Plk1 and cyclin B1 and acetylates Plk1 but not cyclin B1. HIV-1 Tat likely forms a quaternary complex with Tip60, cyclin B1 and Plk1. Fluorescent microscopy showed that Tat causes an unscheduled nuclear translocation of both cyclin B1 and Plk1, causing their co-localization with Tip60 in the nucleus. Tat, Tip60, cyclin B1 and Plk1 interactions provide new a mechanistic explanation for Tat-mediated cell cycle dysregulation and apoptosis. © 2012 Landes Bioscience.

Recknagel F.,University of Adelaide | Ostrovsky I.,Israel Oceanographic And Limnological Research | Cao H.,University of Adelaide | Zohary T.,Israel Oceanographic And Limnological Research | Zhang X.,CAS Research Center for Eco Environmental Sciences
Ecological Modelling | Year: 2013

The hybrid evolutionary algorithm (HEA) was implemented to model and analyze population dynamics of the different phytoplankton phyla (chlorophyta, bacillariophyta, cyanophyta and dinophyta) in relation to physical, chemical, and biological determinants and their combinations in a large lake. Biweekly measurements over a 12-year period were used as input. The validation of models obtained with HEA showed the best results for bacillariophyta and dinophyta resulting in coefficients of determination (r2) between the modeled and measured data of 0.54-0.79 and 0.29-0.76 for these phyla, respectively, suggesting good predictability of their dynamics. The lowest adequacy of HEA models was found for cyanophyta (r2 of 0.28-0.46). Models that combined physical, chemical and biological inputs scored highest, whilst zooplankton-based models scored lowest in all experiments and indicated that top-down control of algal biomass could have only secondary effect. The input sensitivity analysis was used for testing the best phytoplankton models with threshold values determining high or low algal biomass and inhibitory-excitatory effects of specific parameters. Wavelets were tested to analyze two extreme cases of dinophyta dynamics in years of its exceptionally high and low developments to gain insights into lag times between the exert of key factor and algae response. Lag times extracted from daily interpolated data of highly correlated inputs of dinophyta in 1998 varied between 2 and 4 days. © 2013.

Zhou W.,CAS Research Center for Eco Environmental Sciences | Cadenasso M.L.,University of California at Davis
Landscape Ecology | Year: 2012

Landscape ecology links landscape pattern to ecological function. Achieving this goal hinges on accurate depiction and quantification of pattern, which is frequently done by visually interpreting remotely sensed imagery. Therefore, understanding both the accuracy of that interpretation and what influences its accuracy is crucial. In addition, imagery is pixel-based but landscape pattern exists, more realistically, as irregularly shaped patches. Patches may contain only one feature type such as trees, but, in some landscapes, patches may contain several different types of features such as trees and buildings. Using a patch-based approach, this paper investigates two types of variables-whole-patch and within-patch-that are hypothesized to influence the accuracy of visually estimating the cover of features within patches. A highly accurate reference map, obtained from object-based classification, was used to evaluate the accuracy of visual estimates of cover within patches. The effects of the variables on the accuracy of these estimates were tested using logistic regressions and multimodel inferential procedures. Though all variables significantly affected the accuracy, the within-patch configuration of features is the most significant factor. In general, errors of cover estimates are more likely to occur when patches are smaller or have more complex shapes, and features within a patch are (1) more diverse; (2) more fragmented; (3) more complex in shape; and (4) physically less connected. These results provide an important first step towards a quantitative, spatially explicit model for predicting error of cover estimates and determining under what circumstances estimation error is most likely to occur. © 2012 Springer Science+Business Media B.V.

Wu S.,Zhejiang University of Technology | Zhang L.,CAS Research Center for Eco Environmental Sciences | Chen J.,Zhejiang University of Technology
Applied Microbiology and Biotechnology | Year: 2012

Paracetamol (4'-hydroxyacetanilide, N-acetyl-paminophenol, acetaminophen, and paracetamol) is a widely used over-the-counter analgesic and antipyretic drug. Paracetamol and structural analogs are ubiquitous in the natural environment and easily accumulate in aquatic environment, which have been detected in surface waters, wastewater, and drinking water throughout the world. Paracetamol wastewater is mainly treated by chemical oxidation processes. Although these chemical methods may be available for treating these pollutants, the harsh reaction conditions, the generation of secondary pollutants, and the high operational cost associated with these methods have often made them not a desirable choice. Biodegradation of paracetamol is being considered as an environmentally friendly and low-cost option. The goal of this review is to provide an outline of the current knowledge of biodegradation of paracetamol in the occurrence, degrading bacteria, and proposed metabolic/ biodegrading pathways, enzymes and possible intermediates. The comprehensive understanding of the metabolic pathways and enzyme systems involved in the utilization of paracetamol means will be helpful for optimizing and allowing rational design of biodegradation systems for paracetamol-contaminated wastewater. © Springer-Verlag Berlin Heidelberg 2012.

Wang C.,Beijing Normal University | Wang Z.,Beijing Normal University | Lin L.,Beijing Normal University | Tian B.,CAS Research Center for Eco Environmental Sciences | Pei Y.,Beijing Normal University
Journal of Hazardous Materials | Year: 2012

Effects of low molecular weight organic acids (LMWOAs; citric acid, oxalic acid and tartaric acid) on phosphorus (P) adsorption by ferric-alum water treatment residuals (FARs) were studied. Both batch and column experiments indicated that the effects of LMWOAs on P adsorption were closely related to adsorption time. Initially, all acids presented inhibitory function on P adsorption. The inhibition became weaker with time, eventually promoting P adsorption for citric acid and tartaric acid. In the column experiment with a 61-day duration, high P adsorption rates (>55%) were observed for the test groups containing citric acid and tartaric acid. Interestingly, higher pH likely enhanced P adsorption with the effects of LMWOAs and a distinct relationship between LMWOAs' effects on P adsorption and their concentrations was not observed. Moreover, fractionation of the adsorbed P from the FARs demonstrated that oxalic acid reduced P adsorption capacity, while citric acid and tartaric acid increased. Based on the forms of Fe and Al existing in the FARs and Fourier transform infrared spectroscopy analyses, LMWOAs can promote P adsorption through activating crystalline Fe/Al and preventing crystallization of amorphous Fe/Al to increase P adsorption sites, and can also inhibit P adsorption by competition with adsorption sites. © 2011 Elsevier B.V.

Khan S.,Chinese Institute of Urban Environment | Khan S.,University of Peshawar | Cao Q.,CAS Research Center for Eco Environmental Sciences
Journal of Soils and Sediments | Year: 2012

Purpose: Polycyclic aromatic hydrocarbons (PAH) are persistent, toxic, and carcinogenic contaminants present in soil ecosystem globally. These pollutants are gradually accumulating in wastewater-irrigated soils and lead to the contamination of vegetables. Food chain contamination with PAH is considered as one of the major pathways for human exposure. This study was aimed to investigate the concentrations of PAH in soils and vegetables collected from wastewater-irrigated fields from metropolitan areas of Beijing, China. Origin of PAH, daily intake, and health risks of PAH through consumption of contaminated vegetables were studied. Materials and methods: Soil samples were collected from the upper horizon (0-20 cm) of both wastewater-irrigated and reference sites and sieved (<2 mm mesh) and then followed by freeze-drying at -50°C and 123 ± 2 Pa. Standing vegetables were also collected from the same sites used for soil sampling and divided into roots and shoots, thoroughly washed with deionized water, and freeze-dried. PAH were extracted using the Soxhlet method with 200 mL DCM for 24 h, and the extracts were cleaned with silica adsorption chromatography prepared with silica gel, alumina, and capped with anhydrous sodium. The final concentrated extracts (soil and vegetable) were analyzed using gas chromatography-mass spectrometry (Agilent 6890). Bioaccumulation factors, daily intake of PAH, and carcinogenicity of PAH were calculated by different statistical equations. Results and discussion: Results indicate that the soils and grown vegetables were contaminated with all possible carcinogenic PAH (declared by USEPA 2002) except indeno[1,2,3-c,d]pyrene. The highest concentration (242.9 μg kg-1) was found for benzo(k)fluoranthene (BkF), while lowest (79.12 μg kg-1) for benzo[a]pyrene (BaP). The emission sources of PAH were both pyrogenic and petrogenic in nature. However, the total concentrations of PAH were lower than the permissible limits set by different countries like Canada, Denmark and Germany. Highest total PAH concentration was found in the shoots of Spinacia oleracea L., while lowest in the roots of Raphanus sativus. In this study, the values of total toxic BaP equivalent (TEQ) through consumption of vegetables were found in order of S. oleracea L. > Lactuca sativa L. > Brassica oleracea L. > Brassica napus > Brassica juncea L. > R. sativus L. The data indicate that the daily intake of BaP through consumption of vegetables for adults were lower than virtually safe dose set by the Dutch National Institute for Public Health and the Environment. Conclusions: Our findings indicate that PAH concentrations in soil and vegetables were lower than their respective permissible limits set by different organizations. However, the highest intake of total PAH was estimated through consumption of S. oleracea L. for both adults and children. © 2011 Springer-Verlag.

Hartono S.B.,University of Queensland | Qiao S.Z.,University of Queensland | Liu J.,University of Queensland | Jack K.,University of Queensland | And 4 more authors.
Journal of Physical Chemistry C | Year: 2010

Organo-functionalized FDU-12 type silicas exhibiting large pore sizes and ordered mesoporous structures were synthesized at low reaction (15 °C) and high hydrothermal (160 °C) temperatures via the co-condensation of tetraethoxysilane (TEOS) with a suite of organosilanes, i.e., 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltrimethoxysilane (MPTMS), vinyltrimethoxysilane (VTMS), and phenyltrimethoxysilane (PTMS), in the presence of structure directing micelles formed using the surfactant pluronic F127 and the pore enlarging reagent trimethylbenzene (TMB). Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) confirmed that all synthesized materials possessed a face-centered cubic mesostructure (space group Fm3̄ m), while nitrogen sorption analyses showed that the synthesized materials had extra large pores with cavity sizes of up to 25.4 nm and entrance sizes of up to 10.8 nm. X-ray photoelectron spectroscopy (XPS) and 13C solid-state magic-angle spinning nuclear magnetic resonance (13C-MAS NMR) measurements verified the incorporation of the different organosilanes into the silica network and more importantly on the inner and outer surfaces of the materials. As-obtained mesoporous silicas were tested in protein immobilization studies using bovine serum albumin and the cellulose-hydrolyzing enzyme cellulase, which in itself is a mixture of three large enzymes. Enzyme immobilization efficiency, activity, and stability varied significantly with organic functionality due to size exclusion effects at pore entries, electrostatic and hydrophobic interactions between the organo-functionalized surfaces and the enzymes, and conformational changes of the enzymes which can occur on some of the material surfaces. As a result, phenyl (PTMS)- and thiol (MPTMS)-functionalized FDU-12 mesoporous silicas had a very low adsorption capacity of proteins because of their small pore sizes. Amino (APTES)-functionalized FDU-12 mesoporous silica showed the highest adsorption amount of proteins yet the lowest activity of immobilized cellulase. Cellulase immobilization on vinyl (VTMS)-functionalized FDU-12 mesoporous silica appeared to be the most promising approach, since it occurred with high efficiency, maintained enzyme activity, and provided temporal enzyme stability. © 2010 American Chemical Society.

Gao Y.,CAS Chengdu Institute of Mountain Hazards and Environment | Gao Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhu B.,CAS Chengdu Institute of Mountain Hazards and Environment | Wang T.,CAS Chengdu Institute of Mountain Hazards and Environment | Wang Y.,CAS Research Center for Eco Environmental Sciences
Journal of Hydrology | Year: 2012

Bioavailable phosphorus (P) losses due to agriculture activity in a purple soil watershed in the Sichuan Basin of Southwestern China were monitored to define the hydrological controls of P transport. Our results indicate that the proportion of P that was transported in particulate form increased in the rainy season, and that the mass of total bioavailable P (BAP) loads exhibited seasonal fluctuations, wherein the majority (over 90%) was observed to have been exported between June and September. The proportion of bioavailable dissolved P (BDP) in the BAP discharge budget in the watershed varied between 11% and 15% during the monitoring period. The bioavailable particulate P (BPP) and BDP concentrations of stream water under rainstorm events increased by over 40% in comparison to their annual mean concentrations, and the annual BAP load was primarily dominated by the loads that occurred during rainstorm events in the study year. BAP concentration in groundwater significantly fluctuated with the seasons, and the ratio of total BAP in groundwater to that in surface water gradually increased during the rainy season. Thus, the impact of agriculture on the water quality of this watershed becomes clearly evident. © 2011 Elsevier B.V.

Sun M.,CAS Research Center for Eco Environmental Sciences | Kim G.,Kyungpook National University
Journal of Hydrologic Engineering | Year: 2016

An empirical statistical system for quantitative forecasting of monthly precipitation in Korea has been developed using the cyclostationary empirical orthogonal function s(CSEOF) and the canonical correlation analysis (CCA) with sea surface temperature (SST) data as the predictor. Monthly Korean precipitation and SST data are comprehensively analyzed using the empirical orthogonal function (EOF) technique and the CSEOF technique, respectively, and the CSEOF technique can exhibit the spatial distribution and temporal evolution characteristics of variability along with recurrent seasons of precipitation in Korea. Through a multivariate regression method, the CCA technique is used to forecast precipitation with different lead times, and the forecasting results indicate that the CSEOF-CCA forecasting model agrees well with the observation data and is particularly useful in forecasting seasonal precipitation variations in Korea. © 2015 American Society of Civil Engineers.

Koken M.,Middle East Technical University | Constantinescu G.,University of Iowa | Blanckaert K.,CAS Research Center for Eco Environmental Sciences
Journal of Geophysical Research: Earth Surface | Year: 2013

Sharply curved open channel flow with a flat bed is investigated with eddy-resolving numerical simulations that complement laboratory experiments. The focus is on the role of coherent flow structures, how these structures contribute to shear stresses and the capacity of the flow to pick up sediment at the boundaries, and on changes resulting from increasing the Reynolds number between typical values for laboratory model studies and for field conditions. In sharply curved bends, secondary flow leads to a transverse component of the bed shear stress that is of comparable magnitude as the streamwise component. Just downstream of the bend entrance, the locus of highest velocities migrates outward and separates from the inner bank. A highly energetic thin shear layer containing large-scale eddies develops at the interface between the core of high streamwise velocities and the retarded fluid moving close to the inner bank. Highly energetic Streamwise-Oriented Vortices (SOVs) develop in the zone of retarded flow. Turbulence, the boundary shear stress, and the sediment pickup capacity are considerably increased by the SOVs and the large-scale eddies inside the shear layer. These large-scale turbulent structures are amplified and become more coherent with increasing Reynolds number. The results indicate that flow processes in scaled laboratory flumes and natural rivers are qualitatively similar, although some quantitative Reynolds-number-induced scale effects exist. The paper also discusses application of several improved methods to estimate mean sediment pickup rates for flow in sharply curved bends. Such methods try to account in an approximate way for the effects of large-scale turbulence in numerical simulations that do not resolve these structures. Key Points Reynolds number affects coherent structures and boundary stresses Streamwise oriented vortical cells affect distribution of boundary stress Sediment entrainment is underpredicted if effect of large eddies is neglected ©2013. American Geophysical Union. All Rights Reserved.

Zhao Q.,Shanxi University | Lv Q.,Shanxi University | Wang H.,CAS Research Center for Eco Environmental Sciences
Analytical Chemistry | Year: 2014

Aptamer-based fluorescence anisotropy (FA) assay combines the advantages of affinity aptamers in good stability, easy generation, and facile labeling and the benefits of FA in homogeneous analysis, such as robustness, simplicity, and high reproducibility. By using a fluorophore-labeled aptamer, FA detection of a small molecule is not as easy as detection of protein because the binding of a small molecule cannot cause significant increase of molecular weight of the dye-labeled aptamer. The intramolecular interaction between labeled tetramethylrhodamine (TMR) and DNA aptamer bases dramatically affects the local rotation and FA of TMR. This intramolecular interaction can be altered by aptamer conformation change upon target binding, leading to a significant change of FA of TMR. Taking this unique feature of a TMR-labeled aptamer, we described a noncompetitive aptamer-based fluorescence anisotropy assay for detection of small molecules by using ochratoxin A (OTA) as a model. We successfully identified the specific TMR-labeling sites of aptamers with sensitive FA response to OTA from the 5′-end, 3′-end and the internal thymine (T) bases. The aptamer with a TMR labeled on the 10th T base exhibited a remarkable FA reduction response to OTA (Δr = 0.078), without requiring any proteins or nanomaterials as FA signal enhancers. This FA approach for OTA showed high sensitivity with a detection limit of 3 nM, a dynamic range from 3 nM to 3 μM, and good selectivity over the tested compounds with similar structures to OTA. The new strategy allowed the detection of OTA in diluted red wine and urine samples. © 2013 American Chemical Society.

Yang J.,University of South Australia | Zou L.,University of South Australia | Song H.,Beijing University of Chemical Technology | Hao Z.,CAS Research Center for Eco Environmental Sciences
Desalination | Year: 2011

Capacitive deionization (CDI) is a technology for desalination and water purification that charged ions are electrosorbed on the porous electrodes, thus its performance largely affected by choice of electrodes. In this paper, the MnO2/nanoporous carbon composites were prepared and used as electrodes in CDI. Salt removal efficiency for the MnO2/nanoporous carbon was 16.9μmol/g which was higher than 5.4μmol/g of the commercially available activated carbon (AC). The nanoporous carbons were synthesised using silica templates while their composites were prepared by a co-precipitation method and were characterised carefully. The capacitance of the MnO2/carbon composites (204.7F/g) was higher than the AC (98.6F/g). The capacitance increase may be attributed to the high surface area and suitable pore size distribution properties. Moreover, the MnO2 film provided a high surface adsorption capability and an effective cation intercalation. © 2011 Elsevier B.V.

Xue P.,Chinese Institute of Urban Environment | Yan C.,Chinese Institute of Urban Environment | Sun G.,CAS Research Center for Eco Environmental Sciences | Luo Z.,Chinese Institute of Urban Environment
Environmental Science and Pollution Research | Year: 2012

Introduction: Ceratophyllum demersum L. is a widespread submerged macrophyte in aquatic environments. Methods: Simulation experiments were conducted in the laboratory to investigate arsenic (As) accumulation, speciation, and efflux of C. demersum exposed to arsenate and arsenite solutions. Results: Plant shoots showed a significant accumulation of As with a maximum of 862 and 963 μg As g-1 dry weight after 4 days of exposure to 10 μM arsenate and arsenite, respectively. Regardless of whether arsenate or arsenite was supplied to the plants, arsenite was the predominant species in plant shoots. Furthermore, a dramatically higher influx rate of arsenate compared with arsenite was observed in C. demersum exposed to As solutions without the addition of phosphate (P). Arsenate uptake was considerably inhibited by P in this study, suggesting that arsenate is taken up by C. demersum via the phosphate transporters. However, arsenite uptake was unaffected by P and markedly reduced in the presence of glycerol and antimonite (Sb), indicating arsenite shares the aquaporin transport pathway. In addition, C. demersum rapidly reduces arsenate to arsenite in the shoot of the plant and extrudes most of them (>60 %) to the external solutions. The efflux of arsenite was much higher than that of arsenate; the former is supposed to be both active and passive processes, and the latter through passive leakage. Conclusion: C. demersum is a strong As accumulator and an interesting model plant to study As uptake and metabolism due to the lack of a root-to-shoot translocation barrier. © 2012 Springer-Verlag.

Xiu F.-R.,Fujian University of Technology | Xiu F.-R.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling | Zhang F.-S.,CAS Research Center for Eco Environmental Sciences
Journal of Hazardous Materials | Year: 2012

In this work, an effective and size-controlled process for preparing Cu2O nanomaterials from waste PCBs by supercritical water (SCW) combined with electrokinetic (EK) technique was developed. SCW was used for the pretreatment of waste PCBs, and highly uniform and monodisperse Cu2O nanoparticles with different sizes were prepared successfully from waste PCBs in EK process. Cu2O nanoparticles with average sizes of 5, 11, 25 and 40nm could be prepared in the presence of nanoparticles stabilizer (PVP) with the concentrations of 40, 30, 20 and 10g/L, respectively. The average size of Cu2O nanoparticles decreased from 49.5 to 18.2nm when current density increased from 10 to 20mA/cm2, and the size uniformity of nanoparticles was improved distinctly at a higher current density. The size of Cu2O nanoparticles increased with the increase of EK time, and agglomeration of particles was observed after 8h EK reaction. Up to 90wt% of the Cu in waste PCBs could be recovered as Cu2O nanoparticles under optimized condition. It is believed that the process developed in this study is simple and practical for size-controlled preparation of nanomaterials from waste PCBs or other Cu-rich solid wastes. © 2012 Elsevier B.V.

Zuo X.,Nanjing University of Information Science and Technology | Liu Z.,CAS Research Center for Eco Environmental Sciences | Chen M.,Nanjing University of Information Science and Technology
Bioresource Technology | Year: 2016

This study investigated effect of H2O2 concentrations on copper removal using H2O2 modified hydrothermal carbonization Cymbopogon schoenanthus L. Spreng (HLG). Sorption behaviors of Cu (II) on the modified HLG by 20% H2O2 (mHLG2) could be the most desirable. Based on Langmuir isotherm, the maximum amount of Cu (II) uptake was in the sequence of mHLG2 (53.8 mg g-1) > mHLG1 (44.2 mg g-1) > mHLG3 (42.0 mg g-1) > mHLG0 (35.8 mg g-1), which was higher than the results from majority of previous studies, suggesting that H2O2 modification advanced sorption capacity of hydrothermal biochars evidently. Effect mechanisms exploration indicated that the difference of Cu (II) removal by biochars before and after the modification was mainly related to functional groups. Carboxylic group was responsible for the best sorption property of Cu (II) by mHLG2, which was attributed to its significant relationships with H2O2 modification and Cu (II) removal. © 2016 Elsevier Ltd.

He C.,Beijing Normal University | Tian J.,Georgia Southern University | Shi P.,Beijing Normal University | Hu D.,CAS Research Center for Eco Environmental Sciences
Landscape and Urban Planning | Year: 2011

Based on the existing Urban Expansion Dynamic (UED) model, this paper develops a geographic information system (GIS)-based model that can be used to assess the current and potential spatial stress on a regional wetland ecosystem due to urban expansion. Synthetically utilizing the simulation capability of the UED model and the spatial analysis power of a GIS, this new model takes into account the present disturbance by ongoing urban expansion, the potential disturbance by future urban expansion, the accessibility via the transportation network, and the neighborhood stability. The model is used in particular to simulate the spatial stress on the major wetlands in Beijing from 1991 to 2004. The simulation results are found to be consistent with the actual remote sensing observations: a relatively high spatial stress normally leads to an eventual conversion into urban use. With the future urban lands predicted by the UED model, this model is used to further assess the potential spatial stress of urban expansion on the major wetlands in Beijing by 2015. Moreover, the spatially stressed wetland fringe areas in Beijing are identified based on the total spatial stress combining the current and the potential. These areas are found to be mainly distributed in downtown Beijing and the plains areas that have relatively easy accessibility via the transportation network. Effective measures should be taken to protect such areas from being further disturbed in order to achieve the goal of a more effective conservation of the wetland ecosystems in Beijing. © 2011 Elsevier B.V.

Yan M.,Peking University | Yan M.,University of Washington | Korshin G.,University of Washington | Wang D.,CAS Research Center for Eco Environmental Sciences | Cai Z.,University of Washington
Chemosphere | Year: 2012

High-performance liquid chromatography-size exclusion chromatography (HPLC-SEC) coupled with a multiple wavelength absorbance detector (200-445nm) was used in this study to investigate the apparent molecular weight (AMW) distributions of dissolved organic matter (DOM). Standard DOM, namely humic acid, fulvic acid and hydrophilic acid, from the Suwannee River were tested to ascertain the performance and sensitivity of the method. In addition to four compounds groups: humic substances (Peak 1, AMW 16kD), fulvic acids (Peak 2, AMW 11kD), low AMW acids (Peak 3, AMW 5kD), and low AMW neutral and amphiphilic molecules, proteins and their amino acid building blocks (Peak 4, AMW 3kD), an new group that appears to include low AMW, 6-10kD, humic substances was found based on investigating the spectra at various elution times. The spectroscopic parameter S >365 (slope at wavelengths >365nm) was determined to be a good predictor of the AMW of the DOM. The detector wavelength played an important role in evaluating the AMW distribution. For some fractions, such as the humic and low AMW non-aromatic substances, the error in measurement was ±30% as determined by two-dimensional chromatograms detected at an artificially selected wavelength. HPLC-SEC with multiple wavelength absorbance detection was found to be a useful technique for DOM characterization. It characterized the AMW distributions of DOM more accurately and provided additional, potentially important information concerning the properties of DOM with varying AMWs. © 2012 Elsevier Ltd.

Sun G.-X.,CAS Research Center for Eco Environmental Sciences | Wang X.-J.,China Academy of Transportation Science | Hu Q.-H.,University of Texas at Arlington
Environmental Pollution | Year: 2011

Lead isotopes and heavy metal concentrations were measured in two sediment cores sampled in estuaries of Xiangjiang and Lishui Rivers in Hunan province, China. The presence of anthropogenic contribution was observed in both sediments, especially in Xiangjiang sediment. In the Xiangjiang sediment, the lower 206Pb/ 207Pb and higher 208Pb/ 206Pb ratio, than natural Pb isotope signature (1.198 and 2.075 for 206Pb/ 207Pb and 208Pb/ 206Pb, respectively), indicated a significant input of non-indigenous Pb with low 206Pb/ 207Pb and high 208Pb/ 206Pb. The corresponding concentrations of heavy metals (As, Cd, Zn, Mn and Pb) were much higher than natural values, suggesting the contaminations of heavy metals from extensive ore-mining activities in the region. © 2011 Elsevier Ltd. All rights reserved.

Dou X.,Beijing Forestry University | Li R.,Beijing Forestry University | Zhao B.,CAS Research Center for Eco Environmental Sciences | Liang W.,Beijing Forestry University
Journal of Hazardous Materials | Year: 2010

Galvanic couples composed of zero-valent iron and activated carbon (Fe0/AC) were investigated for As(V) removal from water. The effects of Fe0 to AC mass ratio (FCR), solution pH, ionic strength and co-existing anions (phosphate, carbonate, silicate, nitrate, chloride and sulfate) and humic acid (HA) on As(V) removal were evaluated. The results showed that the optimum mass ratio was 1:1, and Fe0/AC with this ratio was more effective for As(V) removal than Fe0 and AC alone at pH of 7 and ion strength of 0.03M NaCl. The enhanced performance for As(V) removal was fulfilled through an accelerated corrosion process of Fe0, which meant more corrosion products for efficient As(V) removal. The As(V) removal followed a pseudo-first order reaction. The rate constants (k) for 1:1 Fe0/AC and Fe0 alone were 0.802 and 0.330h-1, respectively. Potentiodynamic polarization scans further confirmed that Fe0 corrosion was promoted when Fe0 was coupled with AC. Except silicates, other co-existing anions promoted As(V) removal. No reduction form of As (As(III) or As(0)) could be detected on iron corrosion products (ICPs) and in solutions. Identified ICPs included poorly crystallized lepidocrocite (γ-FeOOH) and magnetite/maghemite (Fe3O4/γ-Fe2O3) for both of Fe0/AC and Fe0 systems. In conclusion, the Fe0/AC couple exhibited higher As removal performance than that of Fe0 alone from water. © 2010 Elsevier B.V.

Liu Y.,Environment Canada | Liu Y.,CAS Research Center for Eco Environmental Sciences | Liggio J.,Environment Canada
Atmospheric Chemistry and Physics | Year: 2014

The mixed-phase relative rates approach for determining aerosol particle organic heterogeneous reaction kinetics is often performed utilizing mass spectral tracers as a proxy for particle-phase reactant concentration. However, this approach may be influenced by signal contamination from oxidation products during the experiment. In the current study, the mixed-phase relative rates technique has been improved by combining a positive matrix factor (PMF) analysis with electron ionization aerosol mass spectrometry (unit-mass resolution), thereby removing the influence of m / z fragments from reaction products on the reactant signals. To demonstrate the advantages of this approach, the heterogeneous reaction between OH radicals and citric acid (CA) was investigated using a photochemical flow tube coupled to a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS). The measured heterogeneous rate constant (k2) of citric acid toward OH was (3.31 ± 0.29) × 10−12 cm3 moleculeg'1 sg'1 at 298 K and (30 ± 3)% relative humidity (RH) and was several times greater than the results utilizing individual m / z fragments. This phenomenon was further evaluated for particulate-phase organophosphates (triphenyl phosphate (TPhP), tris-1,3-dichloro-2-propyl phosphate (TDCPP) and tris-2-ethylhexyl phosphate (TEHP)), leading to k2 values significantly larger than previously reported. The results suggest that heterogeneous kinetics can be significantly underestimated when the structure of the products is highly similar to the reactant and when a non-molecular tracer is measured with a unit-mass resolution aerosol mass spectrometer. The results also suggest that the heterogeneous lifetime of organic aerosol in models can be overestimated due to underestimated OH uptake coefficients. Finally, a comparison of reported rate constants implies that the heterogeneous oxidation of aerosols will be dependent upon a number of factors related to the reaction system, and that a single rate constant for one system cannot be universally applied under all conditions.

Li X.,CAS Research Center for Eco Environmental Sciences | Li X.,Smithsonian Environmental Research Center | Weller D.E.,Smithsonian Environmental Research Center | Jordan T.E.,Smithsonian Environmental Research Center
Journal of Hydrology | Year: 2010

Recent advances in optimizing watershed model calibration have focused mainly on incorporating multiple objective measures of model performance and improving optimization algorithms. However, some parameters vary widely among different calibration locations. We present a watershed model calibration method that combines multi-objective optimization with averaging across multiple calibration sites. Model parameters were first estimated by multi-objective optimization at each calibration site, and then finalized by weighted averaging the parameter values across sites. The weight for each site was calculated from the prediction error at that site. The calibration framework was applied to estimate 16 hydrological and nutrient parameters of the General Watershed Loading Function (GWLF) watershed model at the Rhode River basin, in Maryland, United States of America. When calibrated to a single watershed, GWLF gave reasonable predictions for monthly streamflow (r2 = 0.71-0.78), monthly total nitrogen (TN) loads (r2 = 0.55-0.65), annual streamflow (r2 = 0.80-0.91), and annual TN loads (r2 = 0.67-0.86); but success for total phosphorus (TP) loads varied among watersheds (r2 = 0.41-0.68 for monthly TP loads and r2 = 0.47-0.79 for annual TP loads). In comparison to the single-site calibrations, the multi-site weighted average approach combined with multi-objective optimization reduced the relative cumulative error of predictions in validation watersheds by 3.5-7.4% for monthly streamflow, 3.2-6.3% for monthly TN loads, and 4.3-5.9% for monthly TP loads, respectively. © 2009 Elsevier B.V. All rights reserved.

Zhang M.,Shaanxi Normal University | Guo S.,Shaanxi Normal University | Zheng L.,Shaanxi Normal University | Zhang G.,Shaanxi Normal University | And 3 more authors.
Electrochimica Acta | Year: 2013

Spinel nickel manganese oxide with large specific surface area and suitable pore size has been prepared from an epoxide-driven sol-gel process and followed by calcining treatment. The structural evolution of the samples obtained at different stages has been characterized by XRD, TEM, XPS, IR and N2 adsorption-desorption. The nickel manganese oxide aerogel is firstly obtained and propylene oxide plays an important role in its formation. The nickel manganese oxide aerogel is calcined at 300 °C for 5 h, it transforms into spinel nickel manganese oxide (NiMn2O4 (300)) with a mesoporous structure, and the specific surface area is 201 m2 g -1 and the pore size is around 8-10 nm. The electrochemical properties are characterized by cyclic voltammetry in 1 mol L-1 Na2SO4 electrolyte. The prepared NiMn2O 4 (300) material not only exhibits an ideal capacitive behavior, but also shows good cycling stability in a neutral electrolyte system. The value of specific capacitance reaches as high as 243 F g-1 at a low scan rate (5 mV s-1), and a specific capacitance of 169 F g-1 is obtained and the initial capacitance value of 96% can be maintained after 5000 cycles of the operation at the scan rate of 20 mV s-1. © 2012 Elsevier Ltd.

Zhang Y.,Shandong University | Zhang Y.,Yeshiva University | Bai Y.,Shandong University | Jia J.,Shandong University | And 5 more authors.
Chemical Society Reviews | Year: 2014

Nanotechnology is having a tremendous impact on our society. However, societal concerns about human safety under nanoparticle exposure may derail the broad application of this promising technology. Nanoparticles may enter the human body via various routes, including respiratory pathways, the digestive tract, skin contact, intravenous injection, and implantation. After absorption, nanoparticles are carried to distal organs by the bloodstream and the lymphatic system. During this process, they interact with biological molecules and perturb physiological systems. Although some ingested or absorbed nanoparticles are eliminated, others remain in the body for a long time. The human body is composed of multiple systems that work together to maintain physiological homeostasis. The unexpected invasion of these systems by nanoparticles disturbs normal cell signaling, impairs cell and organ functions, and may even cause pathological disorders. This review examines the comprehensive health risks of exposure to nanoparticles by discussing how nanoparticles perturb various physiological systems as revealed by animal studies. The potential toxicity of nanoparticles to each physiological system and the implications of disrupting the balance among systems are emphasized. © 2014 the Partner Organisations.

Lu F.,CAS Research Center for Eco Environmental Sciences
Mitigation and Adaptation Strategies for Global Change | Year: 2014

Straw incorporation (SI) is a common practice in China and has important implications for agricultural sustainability. This study aimed to quantitatively summarise the response of top soil (0-20 cm) carbon (C) to SI under different agricultural management regimes. Results indicated that compared with straw removal (SR), SI significantly increased soil C storage by 12 %. Moreover, incorporation of chopped straw with tillage treatment (ploughing and rotary tillage) increased C storage compared to unchopped straw without tillage treatment. SI implementation with upland cropping, in the northwest and northeast resulted in higher C storage compared with rice cropping, and in the northern and southern regions. Changes in soil C were observed based on SI variables, including tillage and straw amounts in fine-textured soils, however straw amount rather than tillage treatment exhibited a greater influence on soil C in coarse-textured soils. We concluded SI implementation with increased amounts of chopped straw for a longer duration was favourable to soil C sequestration in Chinese croplands. Furthermore, we estimated if SI was popularised across all of China's agricultural regions, soil C sequestration potential would reach 48.2 ~ 56.2 Tg C year-1. SI practices should therefore be encouraged. © 2014 Springer Science+Business Media Dordrecht.

Jin X.,Tianjin University of Technology | Wang X.,Tianjin University of Technology | Yue J.,Tianjin University of Technology | Cai Y.,CAS Research Center for Eco Environmental Sciences | Zhang H.,Tianjin University of Technology
Electrochimica Acta | Year: 2010

Ordinary electrolysis developed spontaneously to contact glow discharge electrolysis (CGDE) at sufficiently high voltage, with glow discharge taking place around a thin platinum anode which was in contact with electrolyte solution. During this transition, the critical voltage (VD) was an important parameter for the onset of CGDE. The results indicated that V D decreased with the increasing conductivity and then maintained a certain value. The different dimension and material of cathode had little effect on VD. When the electrolyte conductivity was 5.0 mS/cm, V D was hardly affected by electrolyte composition. And the concentrations of H2O2 producing in the anolyte were close in different inert electrolyte. However, the concentrations of H 2O2 in NaCl, NaAc, Na2CO3 and NaHCO3 solution were lower than that in Na2SO4 solution. And the concentration of H2O2 in the anolyte was also decreased by adding a minute amount of CH3OH. © 2010 Elsevier Ltd. All rights reserved.

Zhao J.,Chinese Institute of Urban Environment | Xie D.,Chinese Institute of Urban Environment | Wang D.,Chinese Institute of Urban Environment | Deng H.,CAS Research Center for Eco Environmental Sciences
Environmental Management | Year: 2011

Forest certification is a mechanism involving the regulation of trade of forest products in order to protect forest resources and improve forest management. Although China had a late start in adopting this process, the country has made good progress in recent years. As of July 31, 2009, 17 forest management enterprises and more than one million hectares of forests in China have been certified by the Forest Stewardship Council (FSC). Several major factors affect forest certification in China. The first set is institutional in nature. Forest management in China is based on centralized national plans and therefore lacks flexibility. A second factor is public awareness. The importance and value of forest certification are not widely understood and thus consumers do not make informed choices regarding certified forest products. The third major factor is the cost of certification. Together these factors have constrained the development of China's forest certification efforts. However, the process does have great potential. According to preliminary calculations, if 50% of China's commercial forests were certified, the economic cost of forest certification would range from US0.66-86.63 million while the economic benefits for the forestry business sector could exceed US150 million. With continuing progress in forest management practices and the development of international trade in forest products, it becomes important to improve the forest certification process in China. This can be achieved by improving the forest management system, constructing and perfecting market access mechanisms for certificated forest products, and increasing public awareness of environmental protection, forest certification, and their interrelationship. © 2011 Springer Science+Business Media, LLC.

Suragani R.N.V.S.,Harvard-MIT Division of Health Sciences and Technology | Zachariah R.S.,Harvard-MIT Division of Health Sciences and Technology | Velazquez J.G.,Harvard-MIT Division of Health Sciences and Technology | Liu S.,Harvard-MIT Division of Health Sciences and Technology | And 4 more authors.
Blood | Year: 2012

Heme-regulated eIF2α kinase (Hri) is necessary for balanced synthesis of heme and globin. In addition, Hri deficiency exacerbates the phenotypic severity of β-thalassemia intermedia in mice. Activation of Hri during heme deficiency and in β-thalassemia increases eIF2α phosphorylation and inhibits globin translation. Under endoplasmic reticulum stress and nutrient starvation, eIF2α phosphorylation also induces the Atf4 signaling pathway to mitigate stress. Although the function of Hri in regulating globin translation is well established, its role in Atf4 signaling in erythroid precursors is not known. Here, we report the role of the Hri-activated Atf4 signaling pathway in reducing oxidative stress and in promoting erythroid differentiation during erythropoiesis. On acute oxidative stress, Hri -/-erythroblasts suffered from increased levels of reactive oxygen species (ROS) and apoptosis. During chronic iron deficiency in vivo, Hri is necessary both to reduce oxidative stress and to promote erythroid differentiation. Hri -/- mice developed ineffective erythropoiesis during iron deficiency with inhibition of differentiation at the basophilic erythroblast stage. This inhibition is recapitulated during ex vivo differentiation of Hri -/- fetal liver erythroid progenitors. Importantly, the HrieIF2αP-Atf4 pathway was activated and required for erythroid differentiation. We further demonstrate the potential of modulating Hri-eIF2αP-Atf4 signaling with chemical compounds as pharmaceutical therapies for β-thalassemia. © 2012 by The American Society of Hematology.

Shi X.,CAS Institute of Tibetan Plateau Research | Wu L.,Zhejiang University | Wu L.,University of California at Riverside | Chen W.,CAS Research Center for Eco Environmental Sciences | Wang Q.,CAS Institute of Soil and Water Conservation
Soil Science Society of America Journal | Year: 2011

Transfer of agrochemicals from the soil surface to overland flow is a key process governing pollutant transport from soil to surface waters. Simulation models are effective tools for predicting pollutant loads from overland flow to surface water. In this study, we reviewed and summarized experimental observations to assess the factors that affect this transfer process, including: rainfall, topography, soil hydraulic properties, initial water and solute conditions, and management practices. Th eoretical frameworks and models for describing the transfer process were also reviewed. The existing models were classified into four categories based on their principles: mixing-layer models, interfacial diff usion-controlled models, interfacial-diffusion and rainfall-dispersion models, and empirical models. The assumptions, parameters, applications, limitations or potential issues, and further improvements for each category of the models were discussed. It is recommended that new experimental methods be developed and current theoretical frameworks be further refined by considering the effects of other environmental factors and transport mechanisms on solute transfer from the soil surface to overland flow so that the models can be applied to a wider range of practical field conditions. © Soil Science Society of America.

Feng F.,Chinese Academy of Inspection and Quarantine | Zhao Y.,Chinese Academy of Inspection and Quarantine | Yong W.,Chinese Academy of Inspection and Quarantine | Sun L.,Chinese Academy of Inspection and Quarantine | And 2 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2011

A method combining solid phase extraction with high performance liquid chromatography-electrospray ionization tandem mass spectrometry was developed for the highly sensitive and accurate screening of 40 dyes, most of which are banned in foods. Electrospray ionization tandem mass spectrometry was used to identify and quantify a large number of dyes for the first time, and demonstrated greater accuracy and sensitivity than the conventional liquid chromatography-ultraviolet/visible methods. The limits of detection at a signal-to-noise ratio of 3 for the dyes are 0.0001-0.01. mg/L except for Tartrazine, Amaranth, New Red and Ponceau 4R, with detection limits of 0.5, 0.25, 0.125 and 0.125. mg/L, respectively. When this method was applied to screening of dyes in soft drinks, the recoveries ranged from 91.1 to 105%. This method has been successfully applied to screening of illegal dyes in commercial soft drink samples, and it is valuable to ensure the safety of food. © 2011 Elsevier B.V.

Luo W.,CAS Research Center for Eco Environmental Sciences | Luo W.,VU University Amsterdam | Verweij R.A.,VU University Amsterdam | Van Gestel C.A.M.,VU University Amsterdam
Environmental Pollution | Year: 2014

This study aimed at assessing the bioavailability and toxicity of lead to Eisenia andrei in shooting range soils representing different land uses (forest, grassland, bullet plot). Soils contained 47-2398 mg Pb/kg dry weight (dw), but also had different pH-CaCl2 (3.2-6.8) and organic matter contents (3.8-13%). Therefore artificial soils with different pH and organic matter contents and two natural soils were included as control soils. Earthworms were exposed for 28 days and toxicity and uptake of Pb were related to total, water and 0.01 M CaCl2 extractable and porewater Pb concentrations as well as to soil characteristics. Pb uptake in the earthworms linearly increased with increasing soil concentrations. At >2000 mg Pb/kg dw and pH 3.3-3.5, high earthworm mortality with significant weight loss and complete inhibition of reproduction were recorded. At <1000 mg/kg dw, earthworm reproduction was more related to differences in pH and other soil characteristics than to Pb. © 2013 Elsevier Ltd. All rights reserved.

Gu G.,Shandong University | Fang M.,Shandong University | Du Y.,CAS Research Center for Eco Environmental Sciences
Carbohydrate Research | Year: 2011

A practical method for the efficient and selective cleavage of chloroacetyl protecting group using tetra-n-butylammonium fluoride (TBAF) in THF solution at rt was disclosed. © 2011 Elsevier Ltd. All rights reserved.

Zhang L.,Wuhan University | Liang Y.,Jianghan University | Liang Y.,CAS Research Center for Eco Environmental Sciences | Meng L.,Wuhan University
Polymers for Advanced Technologies | Year: 2010

Thermo-sensitive amphiphilic copolymers, PVCL-PTrpAMT and PVCL-PVP-PTrpAMT of hydrophilic N-vinylcaprolactam (VCL), N-vinylpyrrolidone (NVP), and hydrophobic N-t-Boc-tryptophanamido-N'-methacryl thioureas (TrpAMT) monomers, were synthesized and characterized by 1H NMR, UV-spectroscopy, and GPC-MALLS. The cloud point (CP) measurement showed that hydrophobic PTrpAMT and hydrophilic PVP segments significantly altered the phase transition temperature of PVCL with comparable molecular weight in aqueous solution. The CP of PVP-PTrpAMT solution was 38.0°C, lower by 5.0°C than that of unmodified PVCL. In the presence of phosphate buffer saline (PBS), the CP value of the PVCL polymer decreased by ~2.0°C in comparison to that of the aqueous solution. Fluorescent spectroscopy and TEM studies revealed that PVCL-PTrpAMT and PVCL-PVP-PTrpAMT self-assembled into the spherical micelles, 30-70 nm in diameter, at concentrations over their CMCs in an aqueous solution. Cytotoxicity tests demonstrated that the PVCL copolymers were not harmful to cell viability, which may favor the use of the copolymers as potential thermo-sensitive polymers in pharmaceutical applications. © 2009 John Wiley & Sons, Ltd.

Qu J.,CAS Research Center for Eco Environmental Sciences | Fan M.,University of Wyoming
Critical Reviews in Environmental Science and Technology | Year: 2010

This paper summarizes and presents an overview of the current state of water pollution, as well as recent progress and the potential future development of water pollution control technology, in China. Although China has made significant strides in water environmental protection over the past decades, analysis reveals that water pollution in the nation is still not sufficiently controlled, with a number of surface waters currently suffering varying degrees of pollution. High nitrogen and phosphorous concentrations in many great lakes have caused eutrophication problems, and the frequency of blue algal bloom has increased. Likewise, river pollution has not been effectively controlled. Nitrogen, phosphorous, organic compounds, and heavy metals are ubiquitous in China's rivers, with up to 80% of urban rivers contaminated to varying degreesa situation that continues to deteriorate. Next, eutrophication has occurred in many large reservoirs, with numerous toxic substances negatively affecting water quality. Finally, over-exploitation has caused groundwater quality to deteriorate, and pollution from heavy metals, nitrates, fluorine, and random organic matter has become a primary water quality issue. To resolve these complex environmental problems, water pollution controls and quality improvement technologies have been rapidly developed in China in recent years. Ecological restoration, biological disposal, advanced chemical oxidation, high-efficiency adsorption, and flocculation technologies have been especially prominent in these efforts. Not only have these developments introduced practical innovation to the core technologies, they have also prioritized their systematic integration and application. In order to prevent and control the pollution of lakes and rivers, improve general water quality, and ensure the safety of drinking water supplies, China must perform systematic research on management, pollution control and treatment, ecological restoration, and related water treatment and purification technologies over the next 5 to 15 years through a series of major technology initiatives. These programs will supply the scientific foundation and technological support for achieving the optimum improvement of China's water quality. Copyright © Taylor & Francis Group, LLC.

Wang L.,Beijing University of Chemical Technology | Zhang H.,Beijing University of Chemical Technology | Lu C.,Beijing University of Chemical Technology | Zhao L.,CAS Research Center for Eco Environmental Sciences
Journal of Colloid and Interface Science | Year: 2014

CdTe quantum dots (QDs) can provide high-intensity and photostable luminescent signals when they are used as labeling materials for sensing trace amounts of bioanalytes. However, a major concern is whether the capping ligands of CdTe QDs cause toxic effects in living systems. In the current study, we address this problem through the complete ligand transformation of CdTe QDs from toxic thiolglycolic acid (TGA) to green citrate, which is attributed to the Cd. S bond breaking and the Au. S bond formation. The highly efficient depletion of S atom from the surface of the CdTe QDs occurs after the addition of fluorosurfactant (FSN)-capped gold nanoparticles into TGA-capped CdTe QDs, accompanying with the rapid aggregation of FSN-capped gold nanoparticles via noncrosslinking mechanism in the presence of high salt. After the ligand transformation, negligible differences are observed on both photoluminescence spectra and luminescent quantum yield. In addition, the cytotoxicity of the original and new-born CdTe QDs is detected by measuring cell viability after the nanoparticle treatment. In comparison with the original TGA-capped QDs, the new-born CdTe QDs can induce minimal cytotoxicity against human hepatocellular liver carcinoma (HepG2) cells even at high dosages. Our study indicates that the extremely simple method herein opens up novel pathways for the synthesis of green CdTe QDs, and the as-prepared citrate-capped CdTe QDs might have great potential for biological labeling and imaging applications. © 2013 Elsevier Inc.

Wang H.-F.,CAS Research Center for Eco Environmental Sciences | MacGregor-Fors I.,Institute Ecologia | Lopez-Pujol J.,University of Barcelona
Plant Ecology | Year: 2012

Urbanization is one of the most environmentally damaging of human activities, producing large alterations in ecosystem structure, function, species composition and interactions. In this study, we performed a systematic investigation of the plant species richness and density in the city of Beijing, China. We also assessed which socio-economic factors have most influence on plant diversity. Within the city, we found 551 plant species of 313 genera and 103 families, of which 118 were trees, 99 shrubs, and 296 herbs. Nearly half (48. 3 %) of the total plant species were aliens. Species richness and density were positively correlated both for tree/shrub and herb taxa, which indicate that although some species predominate in our study area, there is an important array of species in relation to their densities. As expected, most of the socio-economic variables studied showed to be related to at least one of the four plant diversity variables (i. e., herb richness, herb density, tree/shrub richness, and tree/shrub density). Land-use showed a significant relationship in all four cases, which generally had lower values in cultural and education areas (areas that in Beijing are generally characterized by large extensions of urbanized land). The year of establishment was also largely related to plant diversity, with higher values for recently developed areas. This was an expected result given the dynamics of the urban development of Beijing during the last 60 years, which consisted of intense urban sprawling, followed by more environmentally-friendly urbanization practices during the 2000s related to the greening of the city for the olympic games. This dynamics also explained the negative relationship found between the distance to the city center and both tree/shrub species richness and density. © 2012 Springer Science+Business Media B.V.

Xie W.-Y.,Chinese Institute of Urban Environment | Su J.-Q.,Chinese Institute of Urban Environment | Zhu Y.-G.,Chinese Institute of Urban Environment | Zhu Y.-G.,CAS Research Center for Eco Environmental Sciences
Applied and Environmental Microbiology | Year: 2015

The phyllosphere of floating macrophytes in paddy soil ecosystems, a unique habitat, may support large microbial communities but remains largely unknown. We took Wolffia australiana as a representative floating plant and investigated its phyllosphere bacterial community and the underlying driving forces of community modulation in paddy soil ecosystems using Illumina HiSeq 2000 platform-based 16S rRNA gene sequence analysis. The results showed that the phyllosphere of W. australiana harbored considerably rich communities of bacteria, with Proteobacteria and Bacteroidetes as the predominant phyla. The core microbiome in the phyllosphere contained genera such as Acidovorax, Asticcacaulis, Methylibium, and Methylophilus. Complexity of the phyllosphere bacterial communities in terms of class number and α-diversity was reduced compared to those in corresponding water and soil. Furthermore, the bacterial communities exhibited structures significantly different from those in water and soil. These findings and the following redundancy analysis (RDA) suggest that species sorting played an important role in the recruitment of bacterial species in the phyllosphere. The compositional structures of the phyllosphere bacterial communities were modulated predominantly by water physicochemical properties, while the initial soil bacterial communities had limited impact. Taken together, the findings from this study reveal the diversity and uniqueness of the phyllosphere bacterial communities associated with the floating macrophytes in paddy soil environments. © 2015, American Society for Microbiology.

Wei M.-Y.,West Virginia University | Guo L.-H.,CAS Research Center for Eco Environmental Sciences | Famouri P.,West Virginia University
Microchimica Acta | Year: 2011

Strategies for electrochemical sensing of DNA can be classified into label-free and label-based approaches, categories of which include enzyme-, nanomaterial- and redox labels that are attached to DNA either by covalent or non-covalent means. Metallointercalators represent one group of small molecule redox labels that non-covalently enter the groove of a DNA. The metallointercalator plays a dual-role in acting as a structure indicator (for hybridization) and a signal generator. Labeling is not needed, and electrochemical measurements can be carried out in a label-free solution of an electrolyte. However, such metallointercalators lack the option of catalytic signal generation as in the case of enzyme- and nanomaterial-based labels. Therefore, signal amplification becomes crucial. We first survey here recent progress in this area. A signal-amplifying system is presented that relies on the electroatalytic oxidation of a metallointercalator ruthenium(II)bipyridine/phenoxazine complex in the presence of electron donor species such as oxalate, DNA bases, or tripropylamine. Recent work on such DNA sensors is discussed. Results suggest that such metallointercalator-based DNA sensors represent a viable platform for developing high-throughput and automated PCR/lab-on-a-chip devices as well as visualized multifunctional DNA sensors. © 2010 Springer-Verlag.

Shi Y.-J.,Shandong University | Wang X.-H.,Shandong University | Yu H.-B.,Shandong University | Xie H.-J.,Shandong University | And 4 more authors.
Bioresource Technology | Year: 2011

In this study, the granulation of nitrifying-denitrifying via nitrite process in a sequencing batch reactor (SBR) as well as N2O emission patterns was investigated. After 60days of operation, 0.8mm granules were obtained, and partial nitrification was achieved after NH4+-N was raised to 350mg/L. Fluorescence In-Situ Hybridization (FISH) analysis indicated that a fairly large proportion of ammonia-oxidizing bacteria (AOB) was close to the surface but nitrite-oxidizing bacteria (NOB) were rarely found. Batch experiments showed that 64.0% of NH4+-N in influent was transformed into NO2--N, which showed the granules had excellent partial nitrification ability. Inhibition of free ammonia (FA) and limited DO diffusion within granules may contribute to the development and stabilization of partial nitrification. This process did not simultaneously lead to increased N2O production. N2O emissions at the anoxic and aerobic phases were 0.06 and 13.13mg N2O/cycle, respectively. © 2010 Elsevier Ltd.

Yan M.,Peking University | Liu C.,Changan University | Wang D.,CAS Research Center for Eco Environmental Sciences | Ni J.,Peking University | Cheng J.,Changan University
Langmuir | Year: 2011

In this paper, a quartz crystal microbalance with dissipation monitoring (QCM-D) is used to investigate humic acid (HA) adsorption onto alumina (Al 2O 3). The amount of adsorption and layer structures of HA were determined by the real-time monitoring of resonance frequency and energy dissipation changes (Δf and ΔD). The effect of HA concentration, HA molecular characteristics (molecular weight and polarity), and pH on HA adsorption onto Al 2O 3 were investigated. The mass of HA adsorption increases as the concentration of HA increases. The masses are about 24, 60, and 87 ng cm -2 as the concentration of DOC is 1.0, 4.85, and 92.0 mg L -1, respectively. The adsorbed layer of HA is more nonrigid, and the mass of HA adsorption is higher at weakly acidic pH values. It was 20, 80, 65, and 45 ng cm -2 at pH values of 4.5, 5.5, 6.5, and 8.0, respectively. This reveals that efficient HA removal by coagulation at weakly acidic pH values is not just due to the hydrolysis of Al ions as previously presumed. The adsorbed layer of hydrophobic HA is more nonrigid than hydrophobic HA (fractionated by Amberlite XAD-8 resin), and the mass adsorption for the hydrophobic fraction is about four times higher than the hydrophilic fraction (120 ng cm -2 and 30 ng cm -2). The method is of value in the research to establish a quantified calculation model for the coagulation process. © 2011 American Chemical Society.

Liang X.,Inner Mongolia University | Zha J.,CAS Research Center for Eco Environmental Sciences
Comparative Biochemistry and Physiology - Part D: Genomics and Proteomics | Year: 2016

Rare minnow (Gobiocypris rarus), a Chinese native species, are an excellent emerging model organism for aquatic toxicity testing and chemical safety assessment. "Big data" omics approaches (i.e., genomics, proteomics, and metabolomics) to inform mechanistic toxicology are now applied to studies in rare minnows to better understand toxicity and molecular pathways perturbed by chemicals. This review highlights recent applications of toxicogenomics to study changes in the gene and protein expression profiles in rare minnows in response to chemicals. Here we briefly describe studies that utilized cDNA microarrays in characterization of the cellular effects of rare minnows in single and mixed chemical exposures. Then we compare gel-based proteomics studies in liver of rare minnows following treatment with endocrine disrupting chemicals including 17β-estradiol, 17α-methyltestosterone, pentachlorophenol, and perfluorooctanoic acid. A total of 90 proteins identified in these studies were functionally annotated and categorized. These responsive proteins have roles in biological processes that include metabolism (37.8%), response to oxidation/chemicals (16.7%), signal transduction (11.1%), transport (10%), cytoskeleton (6.7%) and others (17.8%). In addition, recent investigations of endocrine disrupting effects and neurotoxicity of benzotriazole, an emerging contaminant, are summarized. The objective is to continue to enrich genome and protein databases for this species and to integrate molecular datasets to consider temporal effects and complex regulation at the level of the genome and proteome. © 2016.

Sun G.-X.,CAS Research Center for Eco Environmental Sciences | Van De Wiele T.,Ghent University | Alava P.,Ghent University | Tack F.,Ghent University | Du Laing G.,Ghent University
Environmental Pollution | Year: 2012

Rice, used as staple food for half of the world population, can easily accumulate arsenic (As) into its grain, which often leads to As contamination. The health risk induced by presence of As in food depends on its release from the food matrix, i.e., its bioaccessibility. Using an in vitro gastrointestinal simulator, we incubated two types of cooked rice (total As: 0.389 and 0.314 mg/kg). Arsenic bioaccessibility and speciation changes were determined upon gastrointestinal digestion. Washing with deionized water and cooking did not result in changes of As speciation in the rice although the arsenic content dropped by 7.1-20.6%. Arsenic bioaccessibility of the cooked rice in the small intestine ranged between 38 and 57%. Bioaccessibility slightly increased during digestion in the simulated small intestine and decreased with time in the simulated colon. Significant speciation changes were noted in the simulated colon, with trivalent monomethylarsonate (MMA III) becoming an important species. © 2011 Elsevier Ltd. All rights reserved.

Lu C.,Beijing University of Chemical Technology | Li Q.,Beijing University of Chemical Technology | Chen S.,Beijing University of Chemical Technology | Zhao L.,CAS Research Center for Eco Environmental Sciences | Zheng Z.,Chinese Research Academy of Environmental Sciences
Talanta | Year: 2011

In this study, gold nanorods were firstly found to exhibit a tremendously higher catalytic activity towards luminol chemiluminescence (CL) than spherical gold nanoparticles. More importantly, ultra-trace aminothiols can cause a great CL decrease in the gold nanorod-catalyzed luminol system by the formation of Au-S covalent bonds on the ends of gold nanorods. Aminothiols can occupy the active sites of gold nanorods, and further interrupt the generation of the active oxygen intermediates. Other biomolecules including 19 standard amino acids, alcohols, organic acids and saccharides have no effect on gold nanorod-catalyzed luminol CL signals. Moreover, in order to evaluate the applicability and reliability of the proposed method, it was applied to the determination of glutathione in the cell extracts of Saccharomyces cerevisiae. Good agreements were obtained for the determination of glutathione in the cell extracts of S. cerevisiae between the present approach and a standard Alloxan method. The recoveries of glutathione were found to fall in the range between 96 and 105%. The calibration curve for glutathione was found to be linear from 0.05 to 100 nM, and the detection limit (S/N = 3) was 0.01 nM. The relative standard deviation (RSD) for five repeated measurements of 5.0 nM glutathione was 2.1%. © 2011 Elsevier B.V. All rights reserved.

Deng L.,Shaanxi Normal University | Wang J.,Shaanxi Normal University | Zhu G.,Shaanxi Normal University | Kang L.,Shaanxi Normal University | And 5 more authors.
Journal of Power Sources | Year: 2014

Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance electrochemical capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g-1 has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F g-1 obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2·xH2O while 60 wt% of RuO2 can be saved. A symmetrical electrochemical capacitor based on the RuGR46 electrode is assembled with 0.5 mol L-1 H 2SO4 solution as the electrolyte in a voltage of 0-1.2 V. It can give a high energy density of 20.28 Wh kg-1 at a power density of 600 W kg-1. Moreover, it presents a high power density (14.03 Wh kg-1 at 12 kW kg-1) and excellent cycle performance. © 2013 Elsevier B.V. All rights reserved.

Chu H.,Tongji University | Cao D.,National Engineering Research Center for Urban Pollution Control | Dong B.,Tongji University | Qiang Z.,CAS Research Center for Eco Environmental Sciences
Water Research | Year: 2010

This work investigated the feasibility of treating micro-polluted surface water for drinking water production with a bio-diatomite dynamic membrane reactor (BDDMR) at lab-scale in continuous-flow mode. Results indicate that the BDDMR was effective in removing CODMn, DOC, UV254, NH3-N and trihalomethanes' formation potential (THMFP) at a hydraulic retention time (HRT) of 3.5 h due to its high concentrations of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS). The removal of pollutants was mainly ascribed to microbial degradation in BDDMR because the dynamic membrane alone was much less effective in pollutant removal. Though the diatomite particles (5-20 μm) were much smaller in size than the aperture of the stainless steel support mesh (74 μm), microorganisms and their extracellular polymer substances could bind these particles tightly to form bio-diatomite particles which were completely retained by the support mesh. The analysis of molecular weight (MW) distribution by gel permeation chromatography (GPC) shows that the BDDMR could effectively remove the hydrophilic fraction of dissolved organic materials present in the raw water. © 2009 Elsevier Ltd. All rights reserved.

Wei M.-Y.,West Virginia University | Wei M.-Y.,University of Texas at Arlington | Famouri P.,West Virginia University | Guo L.-H.,CAS Research Center for Eco Environmental Sciences
TrAC - Trends in Analytical Chemistry | Year: 2012

Label-free electrochemical (EC) protein biosensors that derive electrical signal from redox-active amino acid (AA) residues can avoid disruption of delicate protein structures, and thus provide a great opportunity to reveal valid information about protein functions. However, the challenge is that such a signal is usually very limited due to the sluggish EC reaction of free AAs on most common electrodes and slow electron-transfer rates from the deeply-buried AA residues in a protein to the electrode. Signal enhancement therefore becomes crucial. We first survey recent progress in this area.We present a signal-enhancing system that relies on the electrocatalytic oxidation of tyrosine mediated by osmium bipyridine or phenoxazine complexes. We describe several applications of label-free protein EC biosensors based on this detection principle for the analysis of protein functions, including the monitoring of protein-conformation change, study of ligand/protein binding, and detection of protein oxidative damage and protein phosphorylation.We describe related works on protein-function analysis using other signal-enhancing methods. The results suggest that label-free EC protein biosensors are suitable for the rapid survey of protein functions due to their fast response, ease of integration, cost effectiveness and convenience. Proof-of-concept work on the application of our system is paving the way for bio-analytical detections and protein-function analysis in future work. © 2012 Elsevier Ltd.

Sun Q.,South China Normal University | Wang Y.,South China Normal University | Li L.,South China Normal University | Bing J.,CAS Research Center for Eco Environmental Sciences | Yan H.,South China Normal University
Journal of Hazardous Materials | Year: 2015

Comparative experiments were conducted to investigate the catalytic ability of MnOx/SBA-15 for the ozonation of clofibric acid (CA) and its reaction mechanism. Compared with ozonation alone, the degradation of CA was barely enhanced, while the removal of TOC was significantly improved by catalytic ozonation (O3/MnOx/SBA-15). Adsorption of CA and its intermediates by MnOx/SBA-15 was proved unimportant in O3/MnOx/SBA-15 due to the insignificant adsorption of CA and little TOC variation after ceasing ozone in stopped-flow experiment. The more remarkably inhibition effect of sodium bisulfite (NaHSO3) on the removal of TOC in catalytic ozonation than in ozonation alone elucidated that MnOx/SBA-15 facilitated the generation of hydroxyl radicals (OH), which was further verified by electron spin-resonance spectroscopy (ESR). Highly dispersed MnOx on SBA-15 were believed to be the main active component in MnOx/SBA-15. Some intermediates were indentified and different degradation routes of CA were proposed in both ozonation alone and catalytic ozonation. The amounts of small molecular carboxylic acids (i.e., formic acid (FA), acetic acid (AA) and oxalic acid (OA)) generated in catalytic ozonation were lower than in ozonation alone, resulting from the generation of more OH. © 2014 Elsevier B.V..

Liu K.,CAS Dalian Institute of Chemical Physics | Liu K.,CAS Research Center for Eco Environmental Sciences | Wang A.,CAS Dalian Institute of Chemical Physics | Zhang T.,CAS Dalian Institute of Chemical Physics
ACS Catalysis | Year: 2012

Preferential oxidation of CO (PROX) is an important reaction for removing small amounts of CO to a parts-per-million level from the hydrogen-rich stream, which will be ultimately supplied as a fuel to polymer-electrolyte membrane fuel cells. The key to the application of PROX is to develop a highly active and selective catalyst that operates well in a wide temperature window (e.g., 80-180 °C) and has good resistance to CO 2 and steam. In the past decades, various catalyst formulations have been developed, among which platinum group metal catalysts, including Pt, Ru, and Ir - in particular, those modified with promoters such as alkali metals and reducible metal oxides - have received a great deal of attention for their significantly improved catalytic activities in the low-temperature range. In this minireview, the recent advances of the platinum group metal catalysts for the PROX reaction are summarized, including performances of unpromoted and promoted catalysts, reaction mechanisms, and kinetics. In addition, the important roles of hydroxyl groups in the PROX reaction are also discussed. © 2012 American Chemical Society.

Xiu F.-R.,Fujian University of Technology | Xiu F.-R.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling | Qi Y.,Fujian University of Technology | Zhang F.-S.,CAS Research Center for Eco Environmental Sciences
Waste Management | Year: 2013

Waste printed circuit boards (PCBs) contain a large number of metals such as Cu, Sn, Pb, Cd, Cr, Zn, and Mn. In this work, an efficient and environmentally friendly process for metals recovery from waste PCBs by supercritical water (SCW) pre-treatment combined with acid leaching was developed. In the proposed process, waste PCBs were pre-treated by SCW, then the separated solid phase product with concentrated metals was subjected to an acid leaching process for metals recovery. The effect of SCW pre-treatment on the recovery of different metals from waste PCBs was investigated. Two methods of SCW pre-treatment were studied: supercritical water oxidation (SCWO) and supercritical water depolymerization (SCWD). Experimental results indicated that SCWO and SCWD pre-treatment had significant effect on the recovery of different metals. SCWO pre-treatment was highly efficient for enhancing the recovery of Cu and Pb, and the recovery efficiency increased significantly with increasing pre-treatment temperature. The recovery efficiency of Cu and Pb for SCWO pre-treatment at 420. °C was 99.8% and 80%, respectively, whereas most of the Sn and Cr were immobilized in the residue. The recovery of all studied metals was enhanced by SCWD pre-treatment and increased along with pre-treatment temperature. Up to 90% of Sn, Zn, Cr, Cd, and Mn could be recovered for SCWD pre-treatment at 440. °C. © 2013 Elsevier Ltd.

Zheng M.-Z.,Chinese Institute of Urban Environment | Zheng M.-Z.,Wuyi University | Li G.,Chinese Institute of Urban Environment | Sun G.-X.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Plant and Soil | Year: 2013

Background and aims: Efficient accumulation of arsenic (As) in rice (Oryza sativa L.) poses a potential health risk to rice consumers. The aim of this study was to investigate the mechanisms of uptake, transport and distribution of inorganic arsenic (Asi) and dimethylarsinic acid (DMA) in rice plants. Methods: Rice was exposed to Asi (As(V)) and DMA in hydroponics. High-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and synchrotron X-ray fluorescence (SXRF) microprobe were used to determine As concentration and the in situ As distribution. Results: DMA induced abnormal florets before flowering and caused a sharp decline in the seed setting rate after flowering compared to Asi. Rice grains accumulated 2-fold higher DMA than Asi. The distribution of Asi concentration (root > leaf > husk > caryopsis) in As(V) treatments was different from that of the DMA concentration (caryopsis > husk > root ≥ leaf) in DMA treatments. SXRF showed that Asi mainly accumulated in the vascular trace of caryopsis with limited distribution to the endosperm, whereas DMA was observed in both tissues. Conclusions: DMA tended to accumulate in caryopsis and induced higher toxicity to the reproductive tissues resulting in markedly reduced grain yield, whereas Asi mainly remained in the vegetative tissues and had no significant effect on yield. DMA is more toxic than Asi to the reproductive tissues when both of them are at similar concentrations in nutrient solution. © 2012 Springer Science+Business Media B.V.

Wang L.,Copenhagen University | Feng Z.,CAS Research Center for Eco Environmental Sciences | Schjoerring J.K.,Copenhagen University
Agriculture, Ecosystems and Environment | Year: 2013

Wheat is one of the world's most important crops and further increase in wheat yields is required to meet the food demand of the growing global population. It is therefore crucial to know how future climate changes affect wheat yields. The present study quantitatively synthesizes effects of elevated atmospheric CO2 concentration ([CO2]) on wheat (Triticum aestivum L.) physiology and yield by meta-analysis of 59 peer-reviewed papers. The results show that elevated [CO2] (450-800ppm) significantly increased wheat grain yield by 24% with 95% bootstrapped confidence intervals of 20-28% across all studies. The increase was dependent on experimental conditions, such as CO2 exposure method (44% less yield increase in free-air CO2 enrichment than in enclosure studies), rooting system (smaller response in field compared to pot experiments) and possible coinciding stress factors (low nitrogen and drought). The yield stimulation by elevated [CO2] was driven by increased photosynthesis (33%) despite reduced stomatal conductance (-23%), Rubisco total activity (-26%) and content (-14%). Also the foliar chlorophyll (-7.5%) and soluble protein content (-11%) declined significantly and the N concentration in the whole-shoot was reduced by 23%. These changes along with remarkably increased aboveground biomass (28%) demonstrate that the increased growth rates accompanying elevated [CO2] were not matched by increased N acquisition and N assimilation, leading to a dilution of shoot N. The obtained results are discussed in relation to uncertainties associated with up-scaling of wheat yield responses to elevated [CO2]. It is concluded that current predictions of [CO2]-stimulated yield increases may be overstated. Key targets for future plant breeding programs are to select new wheat genotypes which have higher sink capacity for photosynthetic products and are capable of increasing nitrogen uptake under elevated [CO2]. © 2013 Elsevier B.V.

Kong F.,Harbin Institute of Technology | Wang A.,Harbin Institute of Technology | Wang A.,CAS Research Center for Eco Environmental Sciences | Ren H.-Y.,Harbin Institute of Technology
Bioresource Technology | Year: 2014

This modular design could be scalable with successive modules for BES scale-up. This study developed and optimized a modular biocathode materials design in bioelectrochemical system (BES) using composite metal and carbon-based materials. The 4-chlorophenol (4-CP) dechlorination could be improved with such composite materials. Results showed that stainless steel basket (SSB) filled with graphite granules (GG) and carbon brush (CB) (SSB/GG/CB) was optimum for dechlorination, followed by SSB/CB and SSB/GG, with rate constant k of 0.0418±0.0002, 0.0374±0.0004, and 0.0239±0.0002h-1, respectively. Electrochemical impedance spectroscopy (EIS) demonstrated that the composite materials with metal can benefit the electron transfer and decrease the charge transfer resistance to be 80.4Ω in BES-SSB/GG/CB, much lower than that in BES-SSB (1674.3Ω), BES-GG (387.3Ω), and BES-CB (193.8Ω). This modular cathode design would be scalable with successive modules for BES scale-up, and may offer useful information to guide the selection and design of BES materials towards dechlorination improvement in wastewater treatment. © 2014 Elsevier Ltd.

Kong F.,Harbin Institute of Technology | Wang A.,Harbin Institute of Technology | Cheng H.,CAS Research Center for Eco Environmental Sciences | Liang B.,Harbin Institute of Technology
Bioresource Technology | Year: 2014

In this study, BES with bioanode and biocathode was applied to decolorize an azo dye Congo red (CR). Results showed that the Congo red decolorization efficiency (CR-DE) within 23. h in a combined bioanode-biocathode single chamber BES was 98.3. ±. 1.3%, significantly higher than that of mixed solution in a dual chamber BES (67.2. ±. 3.5%) (. P<. 0.005). Various electrodes deployments (horizontal, vertical and surrounding) in the combined bioanode-biocathode BES were further compared based on the decolorization performance and electrochemical characterization. Results indicated that CR-DE within 11. h improved from 87.4. ±. 1.3% to 97.5. ±. 2.3%, meanwhile the internal resistance decreased from 236.6 to 42.2. Ω as modifying the horizontal deployment to be a surrounding deployment. It proved that the combination of bioanode and biocathode with suitable electrodes deployment could accelerate the decolorization of azo dye Congo red, which would be great potential for the application of bioelectrochemical technology in azo dye wastewater treatment. © 2013 Elsevier Ltd.

Huang Y.Z.,Agro Environmental Protection Institute | Zhong M.,CAS Research Center for Eco Environmental Sciences
Atmospheric Environment | Year: 2015

The open top chamber (OTC) method was used in combination with real-time quantitative PCR and terminal restriction fragment length polymorphism (T-RFLP) techniques in the wheat field to study the influence of different levels of O3 concentrations (ambient air filtered by activated carbons, 40ppb, 80ppb and 120ppb) on the quantity and community structure of methanotrophic bacteria. O3 stress can influence the potential methane oxidation rate (PMOR) and potential methane production rate (PMPR) in the farmland soil. O3 treatment of 40ppb improved significantly the 16S rRNA gene copy number in the total methanotrophic bacteria pmoA, and type I and type II methanotrophic bacteria in the soil depth of 0-20cm. When the O3 concentration reached 120ppb, the 16S rRNA gene copy number in the total methanotrophic bacteria pmoA and type I methanotrophic bacteria decreased significantly as compared to the control treatment in 10-20cm layer. The 16s rRNA gene copy number of total methanotrophic bacteria pmoA and type I and type II methanotrophic bacteria were influenced by different O3 concentration and soil depth. The T-RFLP analysis indicated that O3 stress influenced significantly the community structure of the methanotrophic bacteria in soil, causing potential threat to the diversity of methanotrophic bacteria. It seems to imply that the rise of O3 concentration could produce an impact on the carbon cycling and the methane emission of the wheat field soil by changing the community structure and diversity of methanotrophic bacteria, which then influences the global climate change. © 2015 Elsevier Ltd.

Li J.,Beijing University of Chemical Technology | Li Q.,Beijing University of Chemical Technology | Lu C.,Beijing University of Chemical Technology | Zhao L.,CAS Research Center for Eco Environmental Sciences
Analyst | Year: 2011

Fluorosurfactant (FSN)-capped gold nanoparticles (GNPs), which exhibit higher stability at a wider pH range and high ionic strength, were utilized for investigating the chemiluminescence (CL) effect on the reaction between high concentration carbonate (∼0.3 M) and peroxynitrous acid. When the pH of the colloidal solution was 10.2 by dropwise addition of 0.05 M NaOH, FSN-capped GNPs offer an enhanced CL intensity. Based on the CL spectra, XPS spectra and the quenching effect of reactive oxygen species, a possible CL mechanism is proposed. The tolerance of FSN-capped GNPs towards salt concentrations (salt proofing effect) within a large pH range is an interesting feature, compared to the other previously reported work on nanoparticles CL systems. The CL intensity is proportional to the concentration of nitrite in the range from 0.1 to 100 μM. The detection limit (S/N = 3) is 0.036 μM and the relative standard deviation (RSD) for seven repeated measurements of 0.5 μM nitrite was 2.4%. This method has been successfully applied to determine nitrite in tap waters with recoveries of 97-106%. © 2011 The Royal Society of Chemistry.

Deng H.,CAS Research Center for Eco Environmental Sciences | Deng H.,Chinese Institute of Urban Environment
Journal of Environmental Sciences (China) | Year: 2012

The impact of decreased biodiversity on ecosystem stability, or the diversity-stability (D-S) relationship, is one of the major concerns of modern ecological studies. Studies on the D-S relationship for soil microbial communities began in 2000 when the fumigation method was developed to generate different levels of soil microbial biodiversity. The studies used various measures and levels of biodiversity, and covered several functional parameters. Due to the lack of general concepts and reliable approaches to define microbial species, studies on the D-S relationship of soil microbial communities concentrate on genetic diversity and functional diversity more than species diversity. Contradictory results were observed in various studies on D-S relationship with possible factors affecting or even changing the directions of the D-S relationship including: (1) the methods of stability measurement, (2) the techniques in microbial diversity measurement, (3) the measures and levels of diversity, (4) the type and strength of disturbance, (5) the traits of functions, and (6) the hidden treatments stemming from diversity manipulation. We argue that future studies should take diversity, species composition and interaction, and soil environmental conditions holistically into account in D-S studies to develop modeling to predict soil functional stability. We also suggest that studies should be carried out on a wider range of disturbance types and functional parameters, and efforts be shifted towards long-term field studies. © 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Chen H.,Zhejiang University | Yan S.,Zhejiang University | Ye Z.,Chinese Institute of Urban Environment | Meng H.,Zhejiang University | And 2 more authors.
Environmental Science and Pollution Research | Year: 2012

Purpose: Urbanization and industrialization in China has resulted in a dramatic increase in the volume of wastewater and sewage sludge produced from wastewater treatment plants. Problems associated with sewage sludge have attracted increasing attention from the public and urban planners. How to manage sludge in an economically and environmentally acceptable manner is one of the critical issues that modern societies are facing. Methods: Sludge treatment systems consist of thickening, dewatering, and several different alternative main treatments (anaerobic digestion, aerobic digestion, drying, composting, and incineration). Agricultural application, landfill, and incineration are the principal disposal methods for sewage sludge in China. However, sewage sludge disposal in the future should focus on resource recovery, reducing environmental impacts and saving economic costs. Results: The reuse of biosolids in all scenarios can be environmentally beneficial and cost-effective. Anaerobic digestion followed by land application is the preferable options due to low economic and energy costs and material reuse. Conclusion: It is necessary to formulate a standard suitable for the utilization of sewage sludge in China. © 2012 Springer-Verlag.

Ottevanger W.,Technical University of Delft | Blanckaert K.,Technical University of Delft | Blanckaert K.,Ecole Polytechnique Federale de Lausanne | Blanckaert K.,Leibniz Institute of Freshwater Ecology and Inland Fisheries | And 2 more authors.
Geomorphology | Year: 2012

Insight is provided in hydrodynamic processes governing the velocity redistribution in sharp river bends based on simulations of three recent experiments by means of Blanckaert and de Vriend's (2003, 2010) reduced-order nonlinear model without curvature restrictions. This model successfully simulated the flow redistribution and the secondary flow in all three experiments. The results indicate that the flow redistribution is primarily governed by topographic steering, curvature variations and secondary flow, in a broad range of different configurations, including mildly to sharply curved bends, narrow to shallow bends, smooth to rough bends, bends with additional complexities such as horizontal recirculation zones or patches of riverbed vegetation. The relative importance of these three dominant processes is case dependent, and controlled by the parameters C f -1H/B, R/B and streamwise curvature variations. The first parameter characterizes a river reach, whereas the second and third parameters are characteristics of individual bends. Major differences exist between the hydrodynamic processes in mildly and sharply curved bends. First, velocity redistribution induced by curvature variations is negligible in mildly curved bends, but the dominant process in sharp bends. This result is relevant, because most meander models are based on the assumption of weak-curvature variations. Second, nonlinear hydrodynamic interactions play a dominant role in sharp bends, where mild-curvature models overpredict the secondary flow and in some cases even falsely identify it as the dominant process governing the velocity redistribution, which leads to unsatisfactory flow predictions. The reduction in secondary flow strength provoked by the nonlinear hydrodynamic interactions is accompanied by a reduction in the transverse bed slope, which reduces the effect of topographic steering. © 2011 Elsevier B.V..

Chen W.,CAS Research Center for Eco Environmental Sciences | Chen W.,University of California at Riverside | Hou Z.,Shihezi University | Wu L.,University of California at Riverside | And 2 more authors.
Plant and Soil | Year: 2010

The influences of different N fertilization rates and soil salinity levels on the growth and nitrogen uptake of cotton was evaluated with a pot experiment under greenhouse conditions. Results showed that cotton growth measured as plant height was significantly affected by the soil salinity and N-salinity interaction, but not by N alone. Cotton was more sensitive to salinity during the emergence and early growth stages than the later developmental stages. At low to moderate soil salinity, the growth inhibition could be alleviated by fertilizer application. Soil salinity was a dominated factor affecting cotton's above-ground dry mass and root development. Dry mass of seed was reduced by 22%, 52%, and 84% respectively, when the soil salinity level increased from control level of 2.4 dS m -1 to 7.7 dS m -1, 12.5 dS m -1 and to 17.1 dS m -1, respectively. N uptake increased with N fertilization at adequate rates at both low and medium soil salinities but was not influenced by over N fertilization. At higher salinities, N uptake was independent of N rates and mainly influenced by soil salinity. The uptake of K decreased with soil salinity. The concentration of Na, Cl and Ca in plant tissues increased with soil salinity with highest concentrations in the cotton leaf. © The Author(s) 2009.

Qiu G.,Chinese Academy of science | Feng X.,Chinese Academy of science | Jiang G.,CAS Research Center for Eco Environmental Sciences
Science of the Total Environment | Year: 2012

China has become the largest contributor of anthropogenic atmospheric mercury (Hg) in the world owing to its fast growing economy and the largest of populations. Over the last two decades, Hg has become of increasing environmental concern in China and much has been published on its distribution, transportation, methylation, and bioaccumulation in aquatic systems and areas of geologic resource extraction contaminated sites, such as coal-fired power plants, non-ferrous smelters, Hg mining and retorting sites, Au amalgam, landfills, chemical plants, etc.. Environmental compartments, like soil, water, air, and crop from areas of geologic resource extraction contamination, especially from Hg mining regions, exhibit elevated values of total-Hg and MMHg. Risk assessments indicate that the consumption of rice, which has a high bioaccumulation of MMHg, has become the dominant pathway of MMHg exposure of inhabitants living in Hg mining areas. Low concentrations less than 5ngl -1 in total-Hg can be observed in rivers from remote areas, however, high concentrations that reached 1600ngl -1 in total-Hg can be found in rivers from industrial and urban areas. The studies of hydropower reservoirs of southwest China indicated the old reservoirs act as net sinks for total-Hg and net sources of MMHg, while newly established ones act as net sinks for both total-Hg and MMHg, which is in sharp contrast to the evolution of biomethylation in reservoirs established in the boreal belt of North America and Eurasia. Fish from those reservoirs have relatively low levels of total-Hg, which do not exceed the maximum total-Hg limit of 0.5mgkg -1 recommended by WHO. Currently, however, there is still a large data gap regarding Hg even in the areas mentioned above in China, which results in poor understanding of its environmental biogeochemistry. Moreover, for a better understanding of human and environmental health effects caused by the fast growing economy, long-term Hg monitoring campaigns are urgently needed. © 2011 Elsevier B.V.

Liu C.,ShenYang Agricultural University | Li X.,ShenYang Agricultural University | Li X.,CAS Research Center for Eco Environmental Sciences
Urban Forestry and Urban Greening | Year: 2012

Urban forests can play an important role in mitigating the impacts of climate change by reducing atmospheric carbon dioxide (CO 2). Quantification of carbon (C) storage and sequestration by urban forests is critical for the assessment of the actual and potential role of urban forests in reducing atmospheric CO 2. This paper provides a case study of the quantification of C storage and sequestration by urban forests in Shenyang, a heavily industrialized city in northeastern China. The C storage and sequestration were estimated by biomass equations, using field survey data and urban forests data derived from high-resolution QuickBird images. The benefits of C storage and sequestration were estimated by monetary values, as well as the role of urban forests on offsetting C emissions from fossil fuel combustion. The results showed that the urban forests in areas within the third-ring road of Shenyang stored 337,000t C (RMB92.02 million, or $ 13.88 million), with a C sequestration rate of 29,000t/yr (RMB7.88 million, or $ 1.19 million). The C stored by urban forests equaled to 3.02% of the annual C emissions from fossil fuel combustion, and C sequestration could offset 0.26% of the annual C emissions in Shenyang. In addition, our results indicated that the C storage and sequestration rate varied among urban forest types with different species composition and age structure. These results can be used to help assess the actual and potential role of urban forests in reducing atmospheric CO 2 in Shenyang. In addition, they provide insights for decision-makers and the public to better understand the role of urban forests, and make better management plans for urban forests. © 2011 .

Gondal M.A.,King Fahd University of Petroleum and Minerals | Chang X.,King Fahd University of Petroleum and Minerals | Chang X.,Nanjing University of Aeronautics and Astronautics | Sha W.E.I.,University of Hong Kong | And 2 more authors.
Journal of Colloid and Interface Science | Year: 2013

The work presented here deals with the photoreduction in metallic silver nanoparticles onto the surface of Ag3PO4 and resulting photocatalytic activity enhancement toward degradation of dye molecules, namely Rhodamine B (Rh. B) as a model compound, from aqueous solution under UV or visible light irradiation. Our results clearly indicated that the photoactivity of Ag3PO4 was significantly enhanced by depositing an optimum amount of silver nanoparticles, even though the adsorption kinetics rate and capacity decreased after the silver nanoparticles agglomerate extensively. The surface plasmon resonance (SPR) excited between the silver nanoparticles and Rh. B interface is a physical origin and responsible for the boosted photoactivity, which strongly depends on the specific wavelength of the incident light. This work provides and suggests a novel scheme for Ag/Ag3PO4 composites having plasmonic effect on the interface with detailed experimental and theoretical study. © 2012 Elsevier Inc.

Blanckaert K.,Ecole Polytechnique Federale de Lausanne | Blanckaert K.,CAS Research Center for Eco Environmental Sciences
Water Resources Research | Year: 2010

The bed topography and associated flow field are investigated in a laboratory configuration with parameters that are representative for sharp natural meander bends. Zones of inward mass transport are characterized by a quasi-linear transverse bed profile, whereas zones of outward mass transport, induced by pronounced curvature variations, are characterized by a quasi-horizontal shallow point bar at the inside of the bend, a deep pool at the outside, and an increase in overall cross-sectional area. These quasi-bilinear bed profiles can be attributed to the curvature-induced secondary flow that is confined to the pool. Topographic steering, mainly due to mass conservation, concentrates the major part of the discharge over the deepest zones of the bend. But the pattern of depth-averaged velocities, which is relevant with respect to the development of the bed topography, does not show maximum values over the deepest zones. A term-by-term analysis of the depth-averaged streamwise momentum equation reveals that the water surface gradient is the principal mechanism with respect to flow velocity redistribution, although inertia and secondary flow are also processes of dominant order of magnitude. A required condition for the occurrence of adverse pressure gradients and flow recirculation due to planform curvature variations is established. A different type of flow recirculation, due to a subtle feedback between the flow and the bed topography, occurs over the point bar. The neglect of the influence of vertical velocities impinging on the bed in models for sediment transport is identified as a major shortcoming in the modeling of the morphodynamics of meandering river channels. Copyright 2010 by the American Geophysical Union.

Sun H.,Curtin University Australia | Liang H.,Curtin University Australia | Liang H.,CAS Research Center for Eco Environmental Sciences | Zhou G.,Curtin University Australia | Wang S.,Curtin University Australia
Journal of Colloid and Interface Science | Year: 2013

Cobalt oxides (Co) and Al2O3-, SiO2-, and TiO2-supported cobalt oxide catalysts were prepared by an aqueous combustion method using urea and glycine as fuels. Their catalytic performance in activation of OXONE® for phenol degradation in aqueous solution was investigated. It was found that unsupported Co oxide and supported Co oxide presented different mechanisms in activation of OXONE® for phenol degradation. The supported Co catalysts presented higher activity in activation of OXONE® for phenol degradation due to higher dispersion of Co3O4 on the supports and Co(II) coordination sites. The major oxidizing radicals were identified to be SO4- by competitive radical reactions. The Co oxides synthesized from urea or glycine showed a similar activity; however, the supported Co catalysts prepared by glycine fuel exhibited better activity than those prepared by urea. For Al2O3-, SiO2-, and TiO2-supported Co catalysts, Co/TiO2 presented a higher activity in phenol degradation compared with Co/SiO2 and Co/Al2O3. But, Co/SiO2 showed the best stability among the catalysts. Total organic carbon could be reduced by 80%, 72%, and 45% on Co/TiO2, Co/SiO2, and Co/Al2O3, respectively, at 30ppm phenol. Phenol degradation was found to follow the zero-order kinetics. The causes of deactivation were investigated, and the regeneration methods were proposed. © 2012 Elsevier Inc.

Shi H.,Missouri University of Science and Technology | Qiang Z.,CAS Research Center for Eco Environmental Sciences | Adams C.,Utah State University
Chemosphere | Year: 2013

This manuscript addresses identification, analysis, formation and occurrence of key disinfection byproducts (DBPs) formed during chlorination and/or ozonation of both natural seawater (NSW), and synthetic high- and low-bromide saltwater (HBSW and LBSW, respectively). In this study, several groups of water disinfection byproducts were studied, including haloacetic acids (HAAs), halonitromethanes (HNMs), bromate and iodate. Three different water systems were studied including filtered natural seawater (NSW, ca. 64.9mgL-1 Br-), a high-bromide (Br-) saltwater (HBSW, ca. 24.8mgL-1 Br), and low-Br- saltwater (LBSW, ca. 4.3mgL-1Br). Because ozone reacts with Cl- to form free chlorine in seawater and salt water systems, similar DBP patterns were observed for both chlorine and ozone oxidants. The results revealed that some HAAs and HNMs are formed at greater than 100μgL-1 concentrations and are greatly affected by water constituents and formulations when treated with chlorine and ozone. The results showed that in low-Br- water salt water, chlorinated HAAs and HNMs predominated, while much greater concentrations of brominated HAAs and HNMs were produced in both natural and synthetic higher Br- saltwater. Concentrations of bromate and iodate were strongly impacted by factors other than Br- and I- concentrations including whether the system was open or closed. © 2012 Elsevier Ltd.

Ololade I.A.,CAS Research Center for Eco Environmental Sciences
Bulletin of Environmental Contamination and Toxicology | Year: 2010

The study underscores the use of equilibrium partitioning (EqP) to determine bioavailability and the narcosis theory to estimate toxicity of PAHs to benthic invertebrates. Eight PAHs (anthracene, azuleno(2,1-b)thiophene, benz(a)anthracene, carbazole, dibenzothiophene, benz(a)azulene, dibenzo(a,h)anthracene and phenanthrene) were identified with phenanthrene and carbazole recording the highest (6.29 μg/g) and least (0.06 μg/g) concentrations at both seasons. Based on EqP and Narcosis model, the sum of PAHs toxic unit (Σ TU), at both sites is «1, suggesting no likelihood of PAHs toxicity to benthic invertebrates. The study suggests continuous PAH monitoring especially with aquatic species due to their transfer to human via food chain. © Springer Science+Business Media, LLC 2010.

Zhang L.,CAS Research Center for Eco Environmental Sciences
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2012

Based on the archaeal 16S rRNA gene phylogenetic tree, the archaeal domain is divided into two major phyla, Euryarchaeota and Crenarchaeota. During the past 20 years, diverse groups of archaea have been found to be widely distributed in moderate environments with the rapid development and application of molecular techniques in microbial ecology. Increasing evidence demonstrated that these archaea, especially ammonia-oxidizing archaea, play a major role in biogeochemical cycles of nitrogen and carbon elements. These mesophilic archaea were placed initially as a sister group of the Crenarchaeota and named as "non-thermophilic Crenarchaeota". More recently, phylogenetic analyses based on more SSU and SLU rDNA sequences suggested that the non-thermophilic Crenarchaeota constituted a separate phylum of the Archaea that branched off before the separation of Crenarchaeota and Euryarchaeota. The Thaumarchaeota (the Greek "Thaumas", meaning wonder) was therefore proposed for a novel phylum, as the third archaeal phylum. More studies based on r-proteins and comparative genomics confirm that the Thaumarchaeota are distinct from Crenarchaeota. In this paper, we gave a translated Chinese name for Thaumarchaeota and reviewed the recent progress on the phylogeny position, genetics, ecology and physiology of the Thaumarchaeota.

Xie H.Q.,CAS Research Center for Eco Environmental Sciences
Environmental health perspectives | Year: 2013

Deficits in cognitive functioning have been reported in humans exposed to dioxins and dioxin-like compounds. Evidence suggests that dioxins induce cholinergic dysfunction mediated by hypothyroidism. However, little is known about direct effects of dioxins on the cholinergic system. We investigated the action of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on acetylcholinesterase (AChE), a key enzyme in cholinergic neurotransmission. We used SK-N-SH human-derived neuronal cells to evaluate the effect of dioxin exposure on AChE. We consistently found a significant decrease in enzymatic activity of AChE in cultured neurons treated with TCDD. We also found that, unlike organophosphate pesticides that directly act on the catalytic center of AChE, the suppressive effect of dioxin was through transcriptional regulation. The addition of CH223191, an inhibitor of the aryl hydrocarbon receptor (AhR)-dependent pathway, counteracted the TCDD-induced suppression of AChE, suggesting involvement of the AhR-dependent pathway. The existence of putative dioxin-responsive element (DRE) consensus sequences in the human ACHE promoter region further supported this hypothesis. Consistent with the absence of DRE elements in mouse or rat ACHE promoter regions, suppression of AChE by TCDD did not occur in rat neuronal cells, indicating a potential species-specific effect. In SK-N-SH cells, dioxin suppressed the activity of neuronal AChE via AhR-mediated transcriptional down-regulation. This is the first study to report direct interference by dioxin with the cholinergic neurotransmission system.

Zhang H.,Beijing University of Chemical Technology | Zhang L.,Beijing University of Chemical Technology | Lu C.,Beijing University of Chemical Technology | Zhao L.,CAS Research Center for Eco Environmental Sciences | Zheng Z.,Chinese Research Academy of Environmental Sciences
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

It was found that CdTe semiconductor nanocrystals (NCs) can induce a great sensitized effect on chemiluminescence (CL) emission from peroxynitrous acid (ONOOH)-Na 2CO 3 system. CL spectra, fluorescence (FL) spectra, and the quenching effect of reactive oxygen species were used to investigate the CL reaction mechanism. The CL intensity was proportional to the concentration of nitrite in the range from 0.05 to 50 μM. The detection limit (S/N = 3) was 0.024 μM and the relative standard deviation (RSD) for five repeated measurements of 0.5 μM nitrite was 4.2%. This method has been successfully applied to determine nitrite in well water samples with recoveries of 94.0-100.5%. This was the first work for direct (not inhibition effect) determination of analytes using semiconductor NCs-based CL sensor. © 2011 Elsevier B.V. All rights reserved.

Yu D.,CAS Research Center for Eco Environmental Sciences | Han S.,CAS Shenyang Institute of Applied Ecology
Ecosystem Services | Year: 2016

The natural reserves are vital to human well-being, but are also highly sensitive to natural and human-induced disturbances. This paper takes the Changbai Mountain Natural Reserve (CMNR) in Northeastern China as a case to investigate the temporal-spatial variability of ecological capital of natural reserves. The method of Specifications for Assessment of Forest Ecosystem Service in China (LY/T1721-2008) was employed to quantify multiple ecosystem services in the CMNR from 1985 to 2010. Considering the particular requirements of forest ecosystem services and the availability of relevant basic data in the CMNR, this study selected four ecosystem services for 1985, 1997 and 2010 land-use/land-cover conditions: carbon fixation and oxygen release, soil conservation, water conservation and nutrient accumulation. The results show a mix of increases in services (carbon fixation and oxygen release, nutrient accumulation) and decreases in services (water conservation and soil conservation) from 1985 to 2010. Furthermore, we combined quantified and modeled ecosystem services to generate a suite of indices to identify ecosystem services and land-use/land-cover type that need to be targeted for conservation and mitigation. Our assessment can be used by land managers and policy makers in exploring multiple management scenarios and their implications for ecosystem services in natural reserves. © 2016 Elsevier B.V.

Blanckaert K.,Ecole Polytechnique Federale de Lausanne | Blanckaert K.,CAS Research Center for Eco Environmental Sciences | Duarte A.,Ecole Polytechnique Federale de Lausanne | Schleiss A.J.,Ecole Polytechnique Federale de Lausanne
Advances in Water Resources | Year: 2010

Boundary shear stress and flow variability due to its interaction with main flow and secondary currents were investigated under conditions that extend previous research on trapezoidal channels. Secondary currents that scale with the flow depth were found over the entire width in all experiments. These findings contradict the widespread perception that secondary currents die out at a distance of 2.5 times the flow depth from the bank, a perception which is largely based on experiments with smooth boundaries. The reported results indicate that a stable pattern of secondary currents over the entire channel width can only be sustained over a fixed horizontal bed if the bed's roughness is sufficient to provide the required transverse oscillations in the turbulent shear stresses. Contrary to laboratory flumes, alluvial river bed always provide sufficient roughness. The required external forcing of this hydrodynamic instability mechanism is provided by the turbulence-generated near-bank secondary currents. The pattern of near-bank secondary currents depends on the inclination and the roughness of the bank. In all configurations, secondary currents result in a reduction of the bed shear stress in the vicinity of the bank and a heterogeneous bank shear stress that reaches a maximum close to the toe of the bank. Moreover, these currents cause transverse variability of 10-15% for the streamwise velocities and 0.2u* 2-0.3u*- 2 for the bed shear stress. These variations are insufficient to provide the flow variability required in river restoration projects, but nevertheless must be accounted for in the design of stable channels. © 2010 Elsevier Ltd.

Suo Z.,Yantai University | Ma C.,CAS Research Center for Eco Environmental Sciences | Liao W.,Yantai University | Jin M.,Yantai University | Lv H.,Yantai University
Fuel Processing Technology | Year: 2011

Monometallic Au, Pd and bimetallic Au-Pd catalysts supported on SiO 2 were prepared by an impregnation method. Their activities on thiophene hydrodesulfurization (HDS) at atmospheric pressure are found to be as a function of calcination temperature of these catalysts. The bimetallic catalyst calcined in air at 400 °C gives the highest activity among them. The techniques including nitrogen physical adsorption, X-ray diffraction, transmission electron microscopy, and X-ray absorption near edge structure were employed to characterize the structure of these catalysts. The results indicate that the effect of gold particles in AuPd/SiO 2 catalyst can facilitate the reduction of PdO phase as well as inhibit the formation of less active Pd 4S phase. The promotional effect of partially oxidative gold and a little of Pd 0 in AuPd/SiO 2 catalyst is suggested to enhance the HDS activity. The formation of Au xPd y alloy phase improves the resistance to sulfur-poisoning of the bimetallic catalyst. The presence of partially oxidized gold particles is considered to be due to the inter-atomic charge transfer from the Au 5d to the Pd 5d band. © 2011 Elsevier B.V. All rights reserved.

Fang J.,Zhejiang GongShang University | Xu M.-J.,Zhejiang GongShang University | Wang D.-J.,CAS Nanjing Institute of Soil Science | Wen B.,CAS Research Center for Eco Environmental Sciences | Han J.-Y.,Zhejiang GongShang University
Water Research | Year: 2013

This study aims to explore the mechanisms governing the transport and retention kinetics of TiO2 nanoparticle aggregates (NPAs) in flow-through columns of packed sand, particularly under unsaturated conditions. The study was carried out at different pHs (2.6, 7.1, and 9.6) and ionic strengths (ISs) (1.0, 10, and 50 mM). A two-site kinetic attachment model was used to describe transport behaviors of TiO2 NPAs. At low ISs (i.e., 1.0 and 10 mM) and in neutral/alkaline conditions, high mobility of TiO2 NPAs was observed in both saturated and unsaturated conditions. However, the retention of TiO2 NPAs was substantially enhanced at the high IS (50 mM) and in extremely acidity condition (pH = 2.6), because of increased aggregation and straining of TiO2 NPAs during their transport course. The breakthrough curves (BTCs) of TiO2 NPAs under unsaturated and saturated conditions almost overlapped, suggesting that decreasing the water saturation did not enhance the retention of TiO2 NPAs in sand columns. This was probably due to the repulsive interactions existed between negatively charged air-water and TiO2 NPAs systems that resulted in unfavorable attachment conditions. The two-site kinetic attachment model provided a good description for the BTCs of TiO2 NPAs both in saturated and unsaturated conditions. The fitted parameters could successfully explain the transport behaviors of TiO2 NPAs under various solution chemistries. © 2012 Elsevier Ltd.

Yu X.,Catalonia Institute for Energy Research IREC | Yu X.,CAS Institute of Process Engineering | Shavel A.,Catalonia Institute for Energy Research IREC | An X.,University College London | And 5 more authors.
Journal of the American Chemical Society | Year: 2014

Cu2ZnSnS4, based on abundant and environmental friendly elements and with a direct band gap of 1.5 eV, is a main candidate material for solar energy conversion through both photovoltaics and photocatalysis. We detail here the synthesis of quasi-spherical Cu 2ZnSnS4 nanoparticles with unprecedented narrow size distributions. We further detail their use as seeds to produce CZTS-Au and CZTS-Pt heterostructured nanoparticles. Such heterostructured nanoparticles are shown to have excellent photocatalytic properties toward degradation of Rhodamine B and hydrogen generation by water splitting. © 2014 American Chemical Society.

Chen X.,Southwest University | Zhou J.,CAS Research Center for Eco Environmental Sciences
Environmental Earth Sciences | Year: 2013

The particle size distribution in small watershed changes under different land uses and affects soil erodibility. The aims of this study were (1) to investigate the volume fractal dimension of particle size distribution under different land uses in a typical small watershed of purple soil, (2) to estimate soil erodibilities of various land uses utilizing the Erosion-Productivity Impact Calculator (EPIC) model and the nomogram (NOMO) model, and (3) to relate volume fractal dimension with the soil erodibility used in the Universal Soil Loss Equation (USLE) in purple soil areas. Laser diffractions and double-logarithmic model were used to measure and calculate volume fractal dimension values. The results show that soil volume fractal dimensions were well linearly fitted to the double-logarithmic model with high correlation coefficients of 0.902-0.936 under six land uses in the small watershed. The averaged volume fractal dimension values under different land uses, from high to low were in the order of Zea mays L, Ipomoea batatas, Citrus reticulata Blanco, Setaria viridis, Robinia pseudoacacia L, Pinus massoniana Lamb. The volume fractal dimension was positively correlated to clay particle fraction (R = 0.933). The average soil erodibility values under different land uses from high to low were in the order of Setaria viridis, Citrus reticulata Blanco, Pinus massoniana Lamb, Zea mays L, Ipomoea batatas, Robinia pseudoacacia L while average soil erodibilities from high to low values were in the order of Setaria viridis, Citrus reticulata Blanco, Zea mays L, Ipomoea batatas, Pinus massoniana Lamb, Robinia pseudoacacia L. The soil erodibilities calculated by the two models were similar, and positively correlated (R = 0.630-0.877). The volume fractal dimension values of six land uses were negatively correlated to both soil erodibility estimated by EPIC and by NOMO models. Moreover, the correlations of the volume fractal dimension values of Zea mays L, Ipomoea batatas and Citrus reticulata Blanco estimated by EPIC or NOMO were lower than those of Pinus massoniana Lamb, Robinia pseudoacacia L and Setaria viridis. Further research is needed to determine the influence of volume fractal dimension on the soil erodibility under different land use and managements. © 2013 Springer-Verlag Berlin Heidelberg.

Wang R.,CAS Research Center for Eco Environmental Sciences
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

This paper investigated the ecological reason of unbalanced, inharmonious and unsustainable problems existed in China's fast social-economic development, and summarized the theoretical and methodological progress in Social-Economic- Natural Complex Ecosystem Study after its emergence 30 years ago. The paper explained the concept and approach of ecological integrity, and the scientific foundation, system approach and integrative technology for incorporating ecological civilization into all aspects and the whole process of advancing economic, political, cultural, and social progress. The study also pointed out that the target of ecological research is transformed from components to contexts, from material to information, from structure to function and from academic interests to social wellbeing; and the approach is transformed from quantity measurement to functional order measurement, from optimization to adaptation. Moderately prosperous society, ecological harmonization, and great scientific wisdom are the objectives of China's ecological civilization by 2020.

Shi X.,CAS Research Center for Eco Environmental Sciences | Zhuge H.,CAS Institute of Computing Technology | Zhuge H.,Southwest University
Concurrency Computation Practice and Experience | Year: 2011

Exploring the laws of the nature and the rules of human society is the grand challenge of sciences. The Internet, Web, various communication networks and digital devices are connecting each other to form an enormous cyber space. The cyber space gradually connects the natural physical space via various cyber-physical interfaces to form Cyber Physical Systems. Interacting with humans, Cyber Physical Systems will connect human society to form a new world-Cyber Physical Society. Humans' daily life and work will become increasingly relying on the new world. Billions of years' evolution creates the most elegant and efficient natural ecosystem. It will be ideal if the Cyber Physical Society can be an ecosystem that harmoniously evolves with society, economy, culture, sciences and technologies. The natural ecosystem gives us inspiration to ensure the harmony of the Cyber Physical Society. From ecosystem point of view, this paper proposes the notion, method, scientific issues, general architecture and resource management of Cyber Physical Society. The study of the Cyber Physical Socio Ecology (CPSE) could lead to a new branch of sciences. Copyright © 2010 John Wiley & Sons, Ltd.

Zhang L.-S.,Chinese University of Hong Kong | Wong K.-H.,Chinese University of Hong Kong | Yip H.-Y.,Chinese University of Hong Kong | Hu C.,CAS Research Center for Eco Environmental Sciences | And 3 more authors.
Environmental Science and Technology | Year: 2010

Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr - Ag - Bi2WO6 nanojunction system as a catalyst under visible light (λ ≥ 400 nm) irradiation. The visible-light-driven (VLD) AgBr - Ag - Bi2WO6 nanojunction could completely inactivate 5 x 107 cfu mL-1 E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi 2WO6 superstructure, Ag - Bi2WO6 and AgBr - Ag - TiO2 composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr - Ag - Bi2WO6 nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr - Ag - Bi2WO6 nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K+) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection. © 2010 American Chemical Society.

Shan G.,Nankai University | Ye M.,Nankai University | Zhu B.,CAS Research Center for Eco Environmental Sciences | Zhu L.,Nankai University
Chemosphere | Year: 2013

Chlorinated phenols and perfluoroalkyl acids (PFAAs) are two kinds of pollutants which are widely present in the environment. Considering liver is the primary toxic target organ for these two groups of chemicals, it is interesting to evaluate the possible joint effects of them on liver. In this work, the combined toxicity of pentachlorophenol (PCP) and perfluorooctane sulfonate (PFOS) or perfluorooctanoic acid (PFOA) were investigated using HepG2 cells. The results indicated that PFOS and PFOA could strengthen PCP's hepatotoxicity. Further studies showed that rather than intensify the oxidative stress or promote the biotransformation of PCP, PFOS (or PFOA) might lead to strengthening of the oxidative phosphorylation uncoupling of PCP. By measuring the intracellular PCP concentration and the cell membrane properties, it was suggested that PFOS and PFOA could disrupt the plasma membrane and increase the membrane permeability. Thus, more cellular accessibility of PCP was induced when they were co-exposed to PCP and PFOS (or PFOA), leading to increased cytotoxicity. Further research is warranted to better understand the combined toxicity of PFAAs and other environmental pollutants. © 2013.

Blanckaert K.,CAS Research Center for Eco Environmental Sciences | Blanckaert K.,Ecole Polytechnique Federale de Lausanne | Blanckaert K.,Technical University of Delft
Journal of Geophysical Research: Earth Surface | Year: 2011

The migration rate of sharp meander bends exhibits large variance and indicates that some sharply curved bends tend to stabilize. These observations remain unexplained. This paper examines three hydrodynamic processes in sharp bends with fixed banks and discusses their morphological implications: secondary flow saturation, outer-banks cells, and inner-bank flow separation. Predictions from a reduced-order hydrodynamic model show that nonlinear hydrodynamic interactions limit the growth of the secondary flow. This process is called the saturation of the secondary flow. For outer-bank cells and inner-bank flow separation, the analysis relies on experimental findings from flume studies in channels with fixed and mobile beds. The experiments reveal that outer-bank cells exist near steep as well as shelving banks and amplify with increasing steepness and roughness of the outer bank, and especially with increasing curvature. The effects of flow separation at the inner bank are found to be strongly conditioned by flow-sediment interactions, which lead to an increased scour depth near the outer bank and increased velocities near the toe of that bank. Overall the results suggest that secondary flow saturation and outer-bank cells tend to inhibit meander migration, whereas inner-bank separation may enhance migration. The relative importance of these three hydrodynamic processes depends on hydraulic, geometric, and sedimentologic conditions, which is consistent with the large variance in observed migration rates. The results suggest that large shallow rivers have the most dynamic meandering behavior, while the occurrence of stabilized meanders seems to be favored in narrow rivers. Copyright 2011 by the American Geophysical Union.

Zhang L.,Zhejiang University of Technology | Zhang L.,CAS Research Center for Eco Environmental Sciences | Hu J.,Zhejiang University of Technology | Zhu R.,Zhejiang University of Technology | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2013

Three bacterial strains utilizing paracetamol as the sole carbon, nitrogen, and energy source were isolated from a paracetamol-degrading aerobic aggregate, and assigned to species of the genera Stenotrophomonas and Pseudomonas. The Stenotrophomonas species have not included any known paracetamol degraders until now. In batch cultures, the organisms f1, f2, and fg-2 could perform complete degradation of paracetamol at concentrations of 400, 2,500, and 2,000 mg/L or below, respectively. A combination of three microbial strains resulted in significantly improved degradation and mineralization of paracetamol. The co-culture was able to use paracetamol up to concentrations of 4,000 mg/L, and mineralized 87.1 % of the added paracetamol at the initial of 2,000 mg/L. Two key metabolites of the biodegradation pathway of paracetamol, 4-aminophenol, and hydroquinone were detected. Paracetamol was degraded predominantly via 4-aminophenol to hydroquinone with subsequent ring fission, suggesting new pathways for paracetamol-degrading bacteria. The degradation of paracetamol could thus be performed by the single isolates, but is stimulated by a synergistic interaction of the three-member consortium, suggesting a possible complementary interaction among the various isolates. The exact roles of each of the strains in the consortium need to be further elucidated. © 2012 Springer-Verlag.

Zhang G.,China Agricultural University | Cao Z.-P.,China Agricultural University | Hu C.-J.,CAS Research Center for Eco Environmental Sciences
Chinese Journal of Applied Ecology | Year: 2011

Soil organic carbon is of heterogeneity in components. The active components are sensitive to agricultural management, while the inert components play an important role in carbon fixation. Soil organic carbon fractionation mainly includes physical, chemical, and biological fractionations. Physical fractionation is to separate the organic carbon into active and inert components based on the density, particle size, and its spatial distribution; chemical fractionation is to separate the organic carbon into various components based on the solubility, hydrolizability, and chemical reactivity of organic carbon in a variety of extracting agents. In chemical fractionation, the dissolved organic carbon is bio-available, including organic acids, phenols, and carbohydrates, and the acid- hydrolyzed organic carbon can be divided into active and inert organic carbons. Simulated enzymatic oxidation by using KMnO4 can separate organic carbon into active and non-active carbon. Biological fractionation can differentiate microbial biomass carbon and potential mineralizable carbon. Under different farmland management practices, the chemical composition and pool capacity of soil organic carbon fractions will have different variations, giving different effects on soil quality. To identify the qualitative or quantitative relationships between soil organic carbon components and carbon deposition, we should strengthen the standardization study of various fractionation methods, explore the integrated application of different fractionation methods, and sum up the most appropriate organic carbon fractionation method or the appropriate combined fractionation methods for different farmland management practices.

Zhou X.,CAS Research Center for Eco Environmental Sciences | Zhou X.,Taiyuan University of Technology | Li Y.,Taiyuan University of Technology | Zhao Y.,Taiyuan University of Technology | Yue X.,Taiyuan University of Technology
Journal of Chemical Technology and Biotechnology | Year: 2013

Background: Biological treatment efficiency of coking wastewater is rather poor, especially for chemical oxygen demand (COD) and ammonia-nitrogen (NH4 +}-N) removal due to its complex composition and high toxicity. Results: A pilot-scale anaerobic/anoxic/oxic/oxic (A2/O2) biofilm system has been developed to treat coking wastewater, focusing attention on the COD and NH4 +}-N removal efficiencies. Operational results over 239 days showed that hydraulic retention time (HRT) of the system had a great impact on simultaneous removals of COD and NH4 +}-N. At HRT of 116 h, total removal efficiencies of COD and NH4 +}-N were 92.3% and 97.8%, respectively, reaching the First Grade discharge standard for coking wastewater in China. Adequate HRT, anoxic removal of refractory organics and two-step aerobic bioreactors were considered to be effective measures to obtain satisfactory coking effluent quality using the A2/O2 biofilm system. The correlation between removal characteristics of pollutants and spatial distributions of biomass along the height of upflow bioreactors was also revealed. CONCLUSION: The study suggests that it is feasible to apply the A2/O2 biofilm process for coking wastewater treatment, achieving desirable effluent quality and steady process performance. © 2012 Society of Chemical Industry.

Luo X.,Nanchang Hangkong University | Ding L.,Nanchang Hangkong University | Luo J.,CAS Research Center for Eco Environmental Sciences
Journal of Chemical and Engineering Data | Year: 2015

Metal organic frameworks (MOFs) have been regarded as robust adsorbents for the adsorptive removal of organic pollutants because of their unique characteristics. However, the application of MOFs in the removal of metals from water is still rare. In this paper, amino-functionalization of Cr-based MOFs MIL-101 are modified through coordination bonding of unsaturated Cr metal centers with the -NH2 group in ethylenediamine (ED), and we demonstrate their excellent performance for the removal of Pb(II) ions from water. The Fourier transform infrared verifies that the ethylenediamine was grafted successfully on MIL-101. Furthermore, the results of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy show that the structure of ED-MIL-101 with an appropriate amount of ED almost does not collapse and retains the original performance of MIL-101. The adsorption capacity of ED-MIL-101, which is more than five times that of MIL-101, is 81.09 mg·g-1 for Pb(II) ions from aqueous samples. The selectivity coefficients of ED-MIL-101 for Pb(II)/Cu(II), Pb(II)/Zn(II), Pb(II)/Co(II), and Pb(II)/Ni(II) are 6.92, 24.02, 15.69, and 14.53, respectively. The adsorption kinetics of Pb(II) ions shows that the process fits well with a pseudo-second-order model, and the adsorption equilibrium time is only about 30 min. Moreover, the practical application of ED-MIL-101 achieves almost 97.22% removal efficiency for Pb(II) ions. These results indicate that ED-MIL-101 has great potential in selectively removing Pb(II) ions from water environment. © 2015 American Chemical Society.

Wu C.,Hong Kong Baptist University | Ye Z.,Sun Yat Sen University | Shu W.,Sun Yat Sen University | Zhu Y.,CAS Research Center for Eco Environmental Sciences | Wong M.,Hong Kong Baptist University
Journal of Experimental Botany | Year: 2011

Root aeration, arsenic (As) accumulation, and speciation in rice of 20 different genotypes with regular irrigation of water containing 0.4 mg As l -1 were investigated. Different genotypes had different root anatomy demonstrated by entire root porosity (ranging from 12.43% to 33.21%), which was significantly correlated with radial oxygen loss (ROL) (R=0.64, P<0.01). Arsenic accumulation differed between genotypes, but there were no significant differences between Indica and Japonica subspecies, as well as paddy and upland rice. Total ROL from entire roots was correlated with metal tolerance (expressed as percentage mean of control straw biomass, R=0.69, P<0.01) among the 20 genotypes; total As concentration (R=-0.67, P<0.01) and inorganic As concentration (R=-0.47, P<0.05) in rice grains of different genotypes were negatively correlated with ROL. There were also significant genotype effects in percentage inorganic As (F=15.8, P<0.001) and percentage cacodylic acid (F=22.1, P<0.001), respectively. Root aeration of different genotypes and variation of genotypes on As accumulation and speciation would be useful for selecting genotypes to grow in areas contaminated by As. © 2011 The Author(s).

Fu B.,CAS Research Center for Eco Environmental Sciences
Acta Geographica Sinica | Year: 2014

Geography is a subject which perceptibly reveals integration and regionalism. The integration means that the diversiform subjects in which geography is involved, and that the regionalism of geography is reflected by the regional differentiation. Through the comprehensive study of the interrelationships among the constituent elements of earth system and the relationship between natural and human systems, it helps us understand the variations of the past, present and future of earth system, and grasp the essence of these changes. Pattern helps us to understand the external features of the world and the process is conducive to the understanding of the internal biophysical mechanism of the world. On the basis of field observations and long- term comprehensive surveys, coupling of patterns and processes at different spatiotemporal scales is an effective way to understand and solve the problems in the field of geography. By analysis of the case studies in the Loess Plateau, the methods of coupling the patterns and processes in the integrated research of geography are discussed and explored. ©, 2014, Science Press. All right reserved.

Zhao Q.,Shanxi University | Geng X.,Shanxi University | Wang H.,CAS Research Center for Eco Environmental Sciences
Analytical and Bioanalytical Chemistry | Year: 2013

We explored a fluorescent strategy for sensing ochratoxin A (OTA) by using a single fluorophore-labeled aptamer for detection of OTA. This method relied on the change of the fluorescence intensity of the labeled dye induced by the specific binding of the fluorescent aptamer to OTA. Different fluorescein labeling sites of aptamers were screened, including the internal thymine bases, 3′-end, and 5′-end of the aptamer, and the effect of the labeling on the aptamer affinity was investigated. Some fluorophore-labeled aptamers showed a signal-on or signal-off response. With the fluorescent aptamer switch, simple, rapid, and selective sensing of OTA at nanomolar concentrations was achieved. OTA spiked in diluted red wine could be detected, showing the feasibility of the fluorescent aptamer for a complex matrix. This method shows potential for designing aptamer sensors for other targets. [Figure not available: see fulltext.] © 2013 Springer-Verlag Berlin Heidelberg.

Zhang S.,CAS Research Center for Eco Environmental Sciences
PloS one | Year: 2012

Ant-aphid mutualism is known to play a key role in the structure of the arthropod community in the tree canopy, but its possible ecological effects for the forest floor are unknown. We hypothesized that aphids in the canopy can increase the abundance of ants on the forest floor, thus intensifying the impacts of ants on other arthropods on the forest floor. We tested this hypothesis in a deciduous temperate forest in Beijing, China. We excluded the aphid-tending ants Lasius fuliginosus from the canopy using plots of varying sizes, and monitored the change in the abundance of ants and other arthropods on the forest floor in the treated and control plots. We also surveyed the abundance of ants and other arthropods on the forest floor to explore the relationships between ants and other arthropods in the field. Through a three-year experimental study, we found that the exclusion of ants from the canopy significantly decreased the abundance of ants on the forest floor, but increased the abundance of beetles, although the effect was only significant in the large ant-exclusion plot (80*60 m). The field survey showed that the abundance of both beetles and spiders was negatively related to the abundance of ants. These results suggest that aphids located in the tree canopy have indirect negative effects on beetles by enhancing the ant abundance on the forest floor. Considering that most of the beetles in our study are important predators, the ant-aphid mutualism can have further trophic cascading effects on the forest floor food web.

Liu Y.,CAS Institute of Geographical Sciences and Natural Resources Research | Fu B.,CAS Research Center for Eco Environmental Sciences
Ecological Indicators | Year: 2016

Sedimentological connectivity is an important issue in soil erosion and sediment transport. Landscape patterns, in combination with the rainfall regime, are known to shape such sedimentological connectivity. The quantification of sedimentological connectivity provides a link between sediment delivery and landscape pattern. There are two categories of connectivity: structural connectivity, which describes the physical coupling of landscape units, and functional connectivity, which delineates the linkage among landscape elements maintained by material transport. To quantify sedimentological connectivity, both the physical coupling of, and material transfer between, the various landscape components need to be assessed. This study quantifies the sedimentological connectivity of a headwater catchment in the Loess Plateau of China using the soil erosion and sediment delivery model (WATEM/SEDEM). Based on the model, two indicators of connectivity were developed: the area of sedimentologically effective catchment area (SEA) that contributes sediment to the sinks, and the minimum sediment output of locations on the flow path that link sources and sinks. This approach effectively represents the annual status of catchment-scale sedimentological connectivity and, furthermore, the simple structure and readily available input data make it highly practicable. However, for larger river systems in which sediment transport between sources and sinks occur over longer time scales and larger spatial scales, we suggest different techniques for quantifying the sediment flux and parameters delineating the physical coupling of landscape units. © 2016 Elsevier Ltd. All rights reserved.

Ren W.,Auburn University | Tian H.,Auburn University | Tao B.,Auburn University | Huang Y.,CAS Institute of Botany | And 2 more authors.
Global Change Biology | Year: 2012

Much concern has been raised about how multifactor global change has affected food security and carbon sequestration capacity in China. By using a process-based ecosystem model, the Dynamic Land Ecosystem Model (DLEM), in conjunction with the newly developed driving information on multiple environmental factors (climate, atmospheric CO 2, tropospheric ozone, nitrogen deposition, and land cover/land use change), we quantified spatial and temporal patterns of net primary production (NPP) and soil organic carbon storage (SOC) across China's croplands during 1980-2005 and investigated the underlying mechanisms. Simulated results showed that both crop NPP and SOC increased from 1980 to 2005, and the highest annual NPP occurred in the Southeast (SE) region (0.32 Pg C yr -1, 35.4% of the total NPP) whereas the largest annual SOC (2.29 Pg C yr -1, 35.4% of the total SOC) was found in the Northeast (NE) region. Land management practices, particularly nitrogen fertilizer application, appear to be the most important factor in stimulating increase in NPP and SOC. However, tropospheric ozone pollution and climate change led to NPP reduction and SOC loss. Our results suggest that China's crop productivity and soil carbon storage could be enhanced through minimizing tropospheric ozone pollution and improving nitrogen fertilizer use efficiency. © 2012 Blackwell Publishing Ltd.

Sheng F.,Shandong Agricultural University | Wang Y.,Jiangsu Academy of Agricultural Sciences | Zhao X.,CAS Research Center for Eco Environmental Sciences | Tian N.,Shandong Agricultural University | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2014

Purple pigments were isolated from mulberry extracts using preparative high-speed countercurrent chromatography (HSCCC) and identified by ESI-MS/MS and high performance liquid chromatography (HPLC) techniques. The solvent system containing methyl tert-butyl ether, 1-butanol, acetonitrile, water, and trifluoroacetic acid (10:30:10:50:0.05; %, v/v) was developed in order to separate anthocyanins with different polarities. Cyanidin 3-O-(6′-O- α-rhamnopyranosyl-β-galactopyranoside) (also known as keracyanin) is the major component present in mulberry (41.3%). Other isolated pigments are cyanidin 3-O-(6′-O-α-rhamnopyranosyl-β-glucopyranoside) and petunidin 3-O-β-glucopyranoside. The binding characteristics of keracyanin with human serum albumin (HSA) were investigated by fluorescence and circular dichroism (CD) spectroscopy. Spectroscopic analysis reveals that HSA fluorescence quenched by keracyanin follows a static mode. Binding of keracyanin to HSA mainly depends on van der Waals force or H-bonds with average binding distance of 2.82 nm. The results from synchronous fluorescence, three-dimensional fluorescence, and CD spectra show that adaptive structure rearrangement and decrease of α-helical structure occur in the presence of keracyanin. © 2014 American Chemical Society.

Li J.,University of Alberta | Wang W.,University of Alberta | Moe B.,University of Alberta | Wang H.,CAS Research Center for Eco Environmental Sciences | Li X.-F.,University of Alberta
Chemical Research in Toxicology | Year: 2015

Halobenzoquinones (HBQs), a new class of disinfection byproducts (DBPs), occur widely in treated drinking water and recreational water. The main concern regarding human exposure to DBPs stems from epidemiological studies that have consistently linked the consumption of chlorinated drinking water with an increased risk of developing bladder cancer. The U.S. Environmental Protection Agency and Health Canada have set regulations on the amount of DBPs in drinking water to minimize the risk. However, these regulated DBPs do not account for the increased risk of bladder cancer because they have different target organs or lower magnitudes of risk based on animal carcinogenesis studies. Because of the pervasive exposure to DBPs, identification of DBPs relevant to human health has become one of the important research targets to address DBP-associated health concerns. Quantitative structure-toxicity relationship (QSTR) analysis has predicted HBQs to be potential bladder carcinogens. Therefore, this perspective focuses on the chemical and toxicological characterization of HBQs. In vitro cytotoxicity experiments have shown that HBQs induce greater cytotoxicity and/or greater developmental toxicity than most of the regulated DBPs. Cellular mechanistic studies indicate that HBQs are capable of producing reactive oxygen species (ROS) either within cells or in solution, depleting cellular glutathione levels, and influencing cellular antioxidant enzymes, which further induces oxidative stress and oxidative damage to cellular proteins and DNA. Oxidative damage to DNA was demonstrated in the form of significant increases in cellular levels of 8-hydroxydeoxyguanosine (8-OHdG), DNA strand breaks, and apurinic/apyrimidinic (AP) sites. HBQs can also form DNA adducts, affect genome-wide DNA methylation, and inhibit DNA repair enzymes. These findings demonstrate that HBQs are highly cytotoxic and potentially genotoxic and carcinogenic, although in vivo data corroborating this is not available. To fully understand the potential adverse health effects and cancer risk due to HBQ exposure, multidisciplinary research is required regarding human exposure, health risk assessment, and toxicological mechanisms of HBQs. © 2015 American Chemical Society.

Han X.B.,CAS Research Center for Eco Environmental Sciences | Han X.B.,Shenzhen Water Group Co. | Yuen K.W.Y.,University of Hong Kong | Wu R.S.S.,University of Hong Kong
Environmental Pollution | Year: 2013

Polybrominated diphenyl ethers (PBDEs) have been commonly used as flame retardants and now become ubiquitous in the global environment. Using zebrafish as a model, we tested the hypothesis that PBDEs may affect the reproduction and development of fish. Zebrafish were exposed to environmentally relevant concentrations of DE-71 (a congener of PBDE commonly found in the environment) throughout their whole life cycle, and the effects of DE-71 on gonadal development, gamete quality, fertilization success, hatching success, embryonic development and sex ratio were investigated. Despite gonadal development was enhanced, reductions in spawning, fertilization success, hatching success and larval survival rate were evident, while significant increases in malformation and percentage of male were also observed in the F1 generation. Our laboratory results suggest that PBDEs may pose a risk to reproductive success and alter the sex ratio of fish in environments highly contaminated with PBDEs. © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

Luo W.,CAS Research Center for Eco Environmental Sciences | Luo W.,VU University Amsterdam | Verweij R.A.,VU University Amsterdam | van Gestel C.A.M.,VU University Amsterdam
Journal of Hazardous Materials | Year: 2014

Understanding bioavailability and toxicity is essential for effective ecological assessment of contaminated soils. Total, water and 0.01M CaCl2 extractable and porewater Pb concentrations and soil properties in different shooting field soils were investigated. Three artificial soils containing different pH and organic matter contents and two natural soils were included as controls. Survival, reproduction and avoidance responses of Folsomia candida exposed to these soils as well as internal Pb concentrations were measured. In the shooting range soils, total Pb concentrations were 47-2398mg/kgdw, pHCaCl2 3.2-6.8 and organic matter content 3.8-7.0%. Pb concentrations in F. candida linearly increased with increasing Pb concentrations in the soils. Acid forest soils caused significantly higher collembolan mortality and avoidance responses and significantly lower reproduction than the neutral grassland soils, which could be attributed to differences in pH and especially CaCl2 extractable Pb concentrations. Soil properties significantly affected bioavailability and toxicity of Pb, but overall the collembolans seemed more sensitive to pH than to Pb in soils. This study shows the importance of selecting proper reference soils for assessing the effects of field soils. © 2014 Elsevier B.V.

Liang H.,Curtin University Australia | Liang H.,CAS Research Center for Eco Environmental Sciences | Sun H.,Curtin University Australia | Patel A.,University of Queensland | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2012

Mesoporous α-MnO 2 and its supported Co 3O 4 nanoparticles were synthesized, characterized and tested in heterogeneous activation of peroxymonosulfate (PMS) for phenol degradation in aqueous solution. α-MnO 2 supported Co 3O 4 presented as nanorod particles and showed H 2 redox reduction at low temperature. Bulk α-MnO 2 and Co 3O 4 could activate peroxymonosulfate to generate sulfate radicals for phenol degradation but at low activity. Co 3O 4/MnO 2 nanoparticles exhibited much high activity in peroxymonosulfate activation for phenol degradation with 100% conversion in 20min and 3wt% is the optimum Co loading. Phenol degradation followed a first order kinetics. Stability tests also showed that Co 3O 4/MnO 2 presented stable performance in phenol degradation in several runs. © 2012 Elsevier B.V.

Zhou J.L.,East China Normal University | Kang Y.,CAS Research Center for Eco Environmental Sciences
Journal of Separation Science | Year: 2013

This paper describes the matrix effect during the analysis of ten antibiotic compounds in water by SPE followed by HPLC-ESI-MS/MS. The target analytes were tetracycline, oxytetracycline (tetracyclines), sulfathiazole, sulfamethazine, sulfadiazine (sulfonamides), erythromycin-H2O, roxithromycine, spiramycin (macrolides), ofloxacin, and norfloxacin (quinolones). The matrix effect was examined for internal standards and the target analytes in five different water matrixes, with signal suppression being increased in the order: ultrapure water, tap water, river water, sewage effluent, and sewage influent. A combined application of the internal standards and matrix-matched extract calibration was shown to be successful in compensating the matrix effect for the analytes. The procedural recovery of the target compounds in sewage effluents and influents was higher than in river water samples, which was further enhanced by sample acidification to pH 2. The validity of the internal standard based matrix-matched calibration approach was verified by the standard addition method. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xiong L.-Y.,Nanjing Normal University | Tang G.-A.,Nanjing Normal University | Li F.-Y.,Nanjing Normal University | Yuan B.-Y.,CAS Institute of Geology and Geophysics | Lu Z.-C.,CAS Research Center for Eco Environmental Sciences
Geomorphology | Year: 2014

The evolution of loess-covered landforms is largely controlled by the pre-Quaternary underlying bedrock terrain, which is one of the most important factors in understanding the formation mechanism of the landforms. This study used multiple data sources to detect 1729 outcropping points of underlying terrain, in order to construct a digital elevation model (DEM) of the paleotopography of an area of the Loess Plateau subject to severe soil erosion. Four terrain characteristics, including terrain texture, slope gradient, the hypsometric curve, and slope aspect, were used to quantify topographic differences and reveal the loess-deposition process during the Quaternary. A loess thickness map was then created to show the spatial distribution of loess deposits in the test area. Finally, the geomorphological inheritance characteristics of the loess-covered landforms were evaluated in different landform divisions. The results showed the significant inheritance of modern topography from the underlying topography with a similar general relief trends. The average thickness of loess deposits was computed to be 104.6. m, with the thickest part located in the Xifeng loess tableland area. In addition, the slope aspects of the North and Northwest seem to have favored Quaternary loess deposition, which supported the hypothesis of an eolian origin for loess in China. The modern surface has lower topographic relief compared to the underlying terrain due to loess deposition. © 2013.

Zhou W.,CAS Research Center for Eco Environmental Sciences
IEEE Geoscience and Remote Sensing Letters | Year: 2013

Digital surface models (DSMs) derived from light detection and ranging (LiDAR) data have been increasingly integrated with high-resolution multispectral satellite/aerial imagery for urban land cover classification. Fewer studies, however, have investigated the usefulness of LiDAR intensity in aid of urban land cover classification, particularly in highly developed urban settings. In this letter, we use an object-based classification approach to investigate whether a combination of LiDAR height and intensity data can accurately map urban land cover. We further compare the approach to a method that uses multispectral imagery as the primary data source, but LiDAR DSM as ancillary data to aid in classification. The study site is a suburban area in Baltimore County, MD. The LiDAR data were acquired in March 2005, from which DSM and two intensity layers (first and last returns), with 1-m spatial resolution were generated, respectively. Four classes were included: 1) buildings; 2) pavement; 3) trees and shrubs; and 4) grass. Our results indicated that the object-based approach provided flexible and effective means to integrate LiDAR height and intensity data for urban land cover classification. A combination of the LiDAR height and intensity data proved to be effective for urban land cover classification. The overall accuracy of the classification was 90.7%, and the overall Kappa statistics equaled 0.872, with the user's and producer's accuracies ranging from 86.8% to 93.6%. The accuracy of the results were far better than those using multispectral imagery alone, and comparable to using DSM data in combination with high-resolution multispectral satellite/aerial imagery. © 2004-2012 IEEE.

Zhang L.,Zhejiang University of Technology | Zhang L.,CAS Research Center for Eco Environmental Sciences | Zhang C.,Zhejiang University of Technology | Cheng Z.,Zhejiang University of Technology | And 2 more authors.
Chemosphere | Year: 2013

A new strain Mycobacterium cosmeticum byf-4 able to simultaneously degrade benzene, toluene, ethylbenzene, and o-xylene (BTE(o-)X) compounds has been isolated and identified previously in our laboratory. We further report here the extent of degradation of every BTE(o-)X component, and unravel the initial mechanism involved in BTE(o-)X degradation. This organism efficiently degrades all the BTE(o-)X components when these compounds are added either individually or as a composite mixture, and has a preference for toluene followed by benzene, ethylbenzene and then o-xylene. The significantly high carbon recovery indicated that the predominant fate for BTE(o-)X compounds was mineralization and incorporation into cell materials. The presence of BTE compounds in binary or ternary mixtures consistently had a negative effect on o-xylene degradation. The initial steps involved in the degradation of BTE(o-)X were investigated by isolation of metabolites and assay of reverse transcription RT-PCR. Isolation of metabolites suggested that the BTE(o-)X compounds were initially converted by a dioxygenase to their respective catechols. The gene sequence of the PCR amplicons revealed that this isolate contained a 454-bp toluene dioxygenase (TOD) fragment. The BTE(o-)X-specific induction of the genes encoding TOD was confirmed by RT-PCR analysis. These results indicated that TOD was possibly responsible for the initial steps of BTE(o-)X catabolism in M. cosmeticum byf-4. © 2012.

Zhang B.,CAS Research Center for Eco Environmental Sciences | Wen Z.,University of Wisconsin - Milwaukee | Ci S.,University of Wisconsin - Milwaukee | Chen J.,University of Wisconsin - Milwaukee | He Z.,Virginia Polytechnic Institute and State University
RSC Advances | Year: 2014

Nitrogen-doped activated carbon was investigated as an alternative cathode catalyst for hydrogen production in microbial electrolysis cells (MECs). Both electrochemical and MEC tests confirmed that nitrogen doping was an effective method in improving the catalytic activity of activated carbon towards the hydrogen evolution reaction (HER). This improvement was attributed to the increased nitrogen content in activated carbon, as a higher content of nitrogen would facilitate the Volmer step in HER. Although the overall performance of the nitrogen-doped activated carbon was lower than the platinum-based catalysts, its low cost and (potentially) long-term stability would compensate for a low hydrogen production rate. This journal is © the Partner Organisations 2014.

Kaiser D.,Leibniz Center for Tropical Marine Ecology | Unger D.,Leibniz Center for Tropical Marine Ecology | Qiu G.,Guangxi Mangrove Research Center | Qiu G.,CAS Research Center for Eco Environmental Sciences
Continental Shelf Research | Year: 2014

Estuarine particle fluxes are an integral part of land-ocean-connectivity and influence coastal environmental conditions. In areas with strong anthropogenic impact they may contribute to coastal eutrophication. To investigate the particulate biogeochemistry of a human affected estuary, we sampled suspended, sedimentary and plant particulate matter along the land-ocean continuum from Nanliu River to Lianzhou Bay in southern China. Riverine particle fluxes exceed inputs from land based pond aquaculture. Elemental (C/N) and isotopic composition of particulate organic carbon (δ13C) and total nitrogen (δ15N) showed that suspended and sedimentary organic matter (OM) mainly derive from freshwater and marine phytoplankton, with minor contributions from terrestrial and aquaculture derived particles. Amino acid composition indicates subseasonal variability of production and freshness of phytoplankton OM. Strongest compositional changes of suspended particles are associated with storm-related extreme precipitation events, which introduce soil derived OM. High concentrations of chlorophyll a reflect eutrophic conditions in riverine and coastal waters. Human impact results in high δ15N signals in suspended, sedimentary and plant particulate matter. Using these in a comparison with two little affected sites shows that anthropogenic influence disperses from the Nanliu River to remote estuaries and mangrove areas. Our results suggest that autochthonous production binds anthropogenic nutrients in particles that are transported along the coast. © 2014 Elsevier Ltd.

Yu Y.,Chinese Academy of Forestry | Yu Y.,CAS Research Center for Eco Environmental Sciences | Jia Z.Q.,Chinese Academy of Forestry | Jia Z.Q.,Qinghai Gonghe Desert Ecosystem Research Station
Solid Earth | Year: 2014

The Gonghe Basin is a sandified and desertified region of China, but the distribution of soil organic carbon (SOC) and total nitrogen (TN) along the cultivation chronosequence across this ecologically fragile region is not well understood. This study was carried out to understand the effects of restoration with Salix cheilophila for different periods of time (6, 11, 16, 21 years) to test whether it enhanced C and N storage. Soil samples, in four replications from seven depth increments (0-10, 10-20, 20-30, 30-50, 50-100, 100-150 and 150-200 cm), were collected in each stand. Soil bulk density, SOC, TN, aboveground biomass and root biomass were measured. Results indicated that changes occurred in both the upper and deeper soil layers with an increase in revegetation time. The 0-200 cm soil showed that the 6-year stand gained 3.89 Mg C ha-1 and 1.00 Mg N ha-1, which accounted for 40.82% of the original SOC and 11.06% of the TN of the 0-year stand. The 11-year stand gained 7.82 Mg C ha-1 and 1.98 Mg N ha-1 in the 0-200 cm soil layers, accounting for 58.06% of the SOC and 19.80% of the TN of the 0-year stand. The 16-year stand gained 11.32 Mg C ha-1 and 3.30 Mg N ha-1 in the 0-200 cm soil layers, accounting for 66.71% of the SOC and 21.98% of the TN of the 0-year stand. The 21-year stand gained 13.05 Mg C ha-1 and 5.45 Mg N ha-1 from the same soil depth, accounting for 69.79% of the SOC and 40.47% of the TN compared with the 0-year stand. The extent of these changes depended on soil depth and plantation age. The results demonstrated that, as stand age increased, the storage of SOC and TN increased. These results further indicated that restoration with S. cheilophila has positive impacts on the Gonghe Basin and has increased the capacity of SOC sequestration and N storage. The shrub's role as carbon sink is compatible with system management and persistence. The findings are significant for assessing C and N sequestration accurately in semi-arid degraded high, cold sandy regions in the future. © Author(s) 2014.

Chen H.-M.,National Cheng Kung University | Zhu B.-Z.,CAS Research Center for Eco Environmental Sciences | Chen R.-J.,National Cheng Kung University | Wang B.-J.,National Cheng Kung University | And 2 more authors.
PLoS ONE | Year: 2014

Pentachlorophenol (PCP) has been used extensively as a biocide and a wood preservative and has been reported to be immunosuppressive in rodents and humans. Tetrachlorohydroquinone (TCHQ) is a major metabolite of PCP. TCHQ has been identified as the main cause of PCP-induced genotoxicity due to reactive oxidant stress (ROS). However, the precise mechanisms associated with the immunotoxic effects of PCP and TCHQ remain unclear. The aim of this study was to examine the effects of PCP and TCHQ on the induction of ROS and injury to primary mouse splenocytes. Our results shown that TCHQ was more toxic than PCP and that a high dose of TCHQ led to necrotic cell death of the splenocytes through induction of massive and sudden ROS and prolonged ROS-triggered ERK activation. Inhibition of ROS production by N-acetyl-cysteine (NAC) partially restored the mitochondrial membrane potential, inhibited ERK activity, elevated caspase-3 activity and PARP cleavage, and, eventually, switched the TCHQ-induced necrosis to apoptosis. We suggest that prolonged ERK activation is essential for TCHQ-induced necrosis, and that ROS play a pivotal role in the different TCHQ-induced cell death mechanisms. © 2014 Chen et al.

Chen W.,CAS Research Center for Eco Environmental Sciences | Hou Z.,Shihezi University | Wu L.,University of California at Riverside | Liang Y.,Shihezi University | Wei C.,Shihezi University
Agricultural Water Management | Year: 2010

In arid and semi-arid regions, salinity is a serious and chronic problem for agriculture. A 3-year field experiment in the arid environment of Xinjiang, northwest China, was conducted to study the salinity change in soil resulting from deficit irrigation of cotton with non-saline, moderate saline and high saline water. The salinity profile distribution was also evaluated by an integrated water, salinity, and nitrogen model, ENVIRO-GRO. The simulated and observed salinity distributions matched well. Results indicated that after 3 years of cotton production, the average salinity in the 1.0-m soil profile was 336% and 547% of the original soil profile, respectively, for moderate saline and high saline water irrigation. If the practices continued, the average soil salinity (ECe) in the 1.0-m soil profile would approach a steady level of 1.7, 10.8, and 14.7dSm-1, respectively, for the treatments receiving irrigation waters of 0.33, 3.62, and 6.71dSm-1. It was concluded that deficit irrigation of saline water in this region was not sustainable. Model simulation showed that a big flood irrigation after harvest can significantly reduce the salt accumulation in the soil profile, and that this practice was much more efficient for salinity control than applying the same extra amount of water during the growing season. © 2010 Elsevier B.V.

Weia H.,University of Illinois at Chicago | Yang R.,University of Illinois at Chicago | Yang R.,CAS Research Center for Eco Environmental Sciences | Li A.,University of Illinois at Chicago | And 2 more authors.
Journal of Chromatography A | Year: 2010

The gas chromatographic (GC) retention times of 180 polybrominated diphenyl ethers (PBDEs) were obtained under different operational conditions on two types of commonly used capillary columns, Restek Rtx-1614 and J&W DB-5MS, of different dimensions. The relative retention times (RRTs) for PBDEs were calculated by normalizing the retention times of individual congeners to the sum of those of BDEs 47 and 183. In clear contrast to polychlorinated biphenyls (PCBs), the elution of PBDEs has few cross-homolog overlaps, and this observation is discussed in terms of molecular conformation with regard to co-planarity. Within a homolog, ortho substitution in PBDEs tends to decrease GC retention, and such an effect is stronger for higher homologs. With the RRT database established in this work, a simple approach is evaluated for the identification of all mono to hepta PBDEs from the RRTs of 39 congeners under various GC conditions to facilitate the identification of unknown PBDE peaks for which chemical standards are not available. © 2010 Elsevier B.V.

He G.,University of California at Davis | Zhao B.,University of California at Davis | Zhao B.,CAS Research Center for Eco Environmental Sciences | Denison M.S.,University of California at Davis
Environmental Toxicology and Chemistry | Year: 2011

Leachate from rubber tire material contains a complex mixture of chemicals previously shown to produce toxic and biological effects in aquatic organisms. The ability of these leachates to induce Ah receptor (AhR)-dependent cytochrome P4501A1 expression in fish indicated the presence of AhR active chemicals, but the responsible chemicals and their direct interaction with the AhR signaling pathway were not examined. Using a combination of AhR-based bioassays, we have demonstrated the ability of tire extract to stimulate both AhR DNA binding and AhR-dependent gene expression and confirmed that the responsible chemicals were metabolically labile. The application of CALUX (chemical-activated luciferase gene expression) cell bioassay-driven toxicant identification evaluation not only revealed that tire extract contained a variety of known AhR-active polycyclic aromatic hydrocarbons but also identified 2-methylthiobenzothiazole and 2-mercaptobenzothiazole as AhR agonists. Analysis of a structurally diverse series of benzothiazoles identified many that could directly stimulate AhR DNA binding and transiently activate the AhR signaling pathway and identified benzothiazoles as a new class of AhR agonists. In addition to these compounds, the relatively high AhR agonist activity of a large number of fractions strongly suggests that tire extract contains a large number of physiochemically diverse AhR agonists whose identities and toxicological/biological significances are unknown. © 2011 SETAC.

Luo W.,CAS Research Center for Eco Environmental Sciences | Luo W.,VU University Amsterdam | Verweij R.A.,VU University Amsterdam | van Gestel C.A.M.,VU University Amsterdam
Soil Biology and Biochemistry | Year: 2014

Variation in soil properties may cause substantial differences in metal bioavailability and toxicity to soil organisms. In this study, lead bioavailability and toxicity to Enchytraeus crypticus was assessed after 21 days exposure to soils from different landscapes of a shooting range containing 47-2398mgPb/kgdry weight (dw). Soils had different pHCaCl2 (3.2-6.8) and organic matter contents (3.8-13% OM), therefore artificial soils with different pH and OM contents and two natural reference soils were included as controls. Effects on survival and reproduction and the uptake of Pb in E.crypticus were related to soil properties and total, water- and CaCl2-extractable and porewater Pb concentrations in the soils. Forest soils with pHCaCl2<3.5 and total Pb concentrations ≥2153mg/kgdw had the highest bioavailability and toxicity of Pb to E.crypticus. At pHCaCl2 3.2 adult survival was inhibited and no juveniles were produced, while at pHCaCl2 3.8 reproduction was also reduced. Bioaccumulation of Pb linearly increased with increasing total soil Pb concentrations. The grassland soils with pHCaCl2>6.5 and total Pb concentrations 355-656mg/kgdw were least toxic. This study shows that E.crypticus was very sensitive to acidic soils with pHCaCl2≤3.8, suggesting that the toxic effects in the most contaminated forest soils may have been due to the low soil pH rather than the high Pb concentrations. © 2014 Elsevier Ltd.

Sang Y.,University of Kiel | Sang Y.,CAS Research Center for Eco Environmental Sciences | Xiong G.,University of Kiel | Maser E.,University of Kiel
Journal of Steroid Biochemistry and Molecular Biology | Year: 2012

The presence of steroid hormones in the aquatic environment is potentially threatening the population dynamics of all kinds of sea animals and public health. Environmental estrogens in water have been reported to be associated with abnormal sexual development and abnormal feminizing responses in some animals. New approaches for the bioremediation of steroid hormones from the environment are therefore urgently sought. We have previously isolated a steroid degrading bacterial strain (H5) from the Baltic Sea, at Kiel, Germany. In the present investigation, 16S rRNA analysis showed that marine strain H5 belongs to the genus Vibrio, family Vibrionaceae and class Gamma-Proteobacteria. To enable identification of steroid inducible genes from bacterial strain H5, a library was constructed of H5 chromosomal DNA fragments cloned into a fluorescent reporter (pKEGFP-2). A reporter plasmid pK3α-4.6-EGFP3 containing the estrogen-inducible gene 3α-hydroxysteroid dehydrogenase/carbonyl reductase (3α-HSD/CR) from Comamonas testosteroni (C. testosteroni) was created as a positive control. Steroid induction could be detected by a microplate fluorescence reader, when the plasmids were transformed into Escherichia coli (E. coli) HB101 cells. With our meta-genomic pKEGFP-2 approach, we identified two estradiol-inducible genes from marine strain H5, which are obviously involved in steroid degradation. Sequencing of the pKEGFP-2 inserts and data base research at NCBI revealed that one gene corresponds to 3-ketosteroid-delta- 1-dehydrogenase from several Mycobacterium strains, while the other showed high similarity to carboxylesterase in Sebadella termitidis and Brachyspira murdochii. Both 3-ketosteroid-delta-1-dehydrogenase and carboxylesterase are one of the first enzymes in steroid degradation. In addition, we identified a strain H5 specific DNA sequence of 480 bp which allows sensitive PCR detection and quantification of strain H5 bacteria in "unknown" seawater samples. Currently, the exact characterization and systematic classification of the marine steroid degrading bacterial strain H5 is envisaged, which might be used for the bioremediation of steroid contaminations in seawater. Article from a special issue on steroids and microorganisms. © 2010 Elsevier Ltd. All rights reserved.

CAS Research Center for Eco Environmental Sciences | Date: 2011-11-09

Disclosed is a Ce-based composite oxide catalyst for selective catalytic reducing nitrogen oxides with ammonia, which comprises Ce oxide and at least one oxide of transition metal except Ce. The Ce-based composite oxide catalyst is prepared by a simple method which uses non-toxic and harmless raw materials, and it has the following advantages: high catalytic activity, and excellent selectivity for generating nitrogen etc. The catalyst can be applied in catalytic cleaning plant for nitrogen oxides from mobile and stationary sources.

Kong F.,Harbin Institute of Technology | Wang A.,Harbin Institute of Technology | Wang A.,CAS Research Center for Eco Environmental Sciences | Ren H.-Y.,Harbin Institute of Technology
Bioresource Technology | Year: 2015

A new integrated system, embedding a modular bioelectrochemical system (BES) with surrounding electrode deployment into an anaerobic sludge reactor (ASR), was developed to improve azo dye decolorization. Results demonstrated that the AO7 decolorization and COD removal can be improved without co-substrate in such system. The kinetic rate of decolorization (0.54h-1) in integrated system was 1.4-fold and 54.0-fold higher than that in biocathode BES (0.39h-1) and ASR (0.01h-1), respectively. COD can be removed after cleavage of azo bond, different from biocathode BES. The combined advantages of this integrated system were achieved by the cooperation of biocathode in modular BES and sludge in ASR. Biocathode was a predominant factor in AO7 decolorization, and anaerobic sludge contributed negligibly to AO7 reduction decolorization but mostly in the COD removal. These results demonstrated the great potential of integrating a BES module with anaerobic treatment process for azo dye treatment. © 2014 Elsevier Ltd.

Hao Z.,University of Burgundy | Hao Z.,China Agricultural University | Hao Z.,CAS Research Center for Eco Environmental Sciences | Fayolle L.,University of Burgundy | And 5 more authors.
Journal of Experimental Botany | Year: 2012

The ectoparasitic dagger nematode (Xiphinema index), vector of Grapevine fanleaf virus (GFLV), provokes gall formation and can cause severe damage to the root system of grapevines. Mycorrhiza formation by Glomus (syn. Rhizophagus) intraradices BEG141 reduced both gall formation on roots of the grapevine rootstock SO4 (Vitis berlandieri×V. riparia) and nematode number in the surrounding soil. Suppressive effects increased with time and were greater when the nematode was post-inoculated rather than co-inoculated with the arbuscular mycorrhizal (AM) fungus. Using a split-root system, decreased X. index development was shown in mycorrhizal and non-mycorrhizal parts of mycorrhizal root systems, indicating that both local and systemic induced bioprotection mechanisms were active against the ectoparasitic nematode. Expression analyses of ESTs (expressed sequence tags) generated in an SSH (subtractive suppressive hybridization) library, representing plant genes up-regulated during mycorrhiza-induced control of X. index, and of described grapevine defence genes showed activation of chitinase 1b, pathogenesis-related 10, glutathione S-transferase, stilbene synthase 1, 5-enolpyruvyl shikimate-3-phosphate synthase, and a heat shock proein 70-interacting protein in association with the observed local and/or systemic induced bioprotection against the nematode. Overall, the data suggest priming of grapevine defence responses by the AM fungus and transmission of a plant-mediated signal to non-mycorrhizal tissues. Grapevine gene responses during AM-induced local and systemic bioprotection against X. index point to biological processes that are related either to direct effects on the nematode or to protection against nematode-imposed stress to maintain root tissue integrity. © 2012 The Author.

Sun R.,CAS Research Center for Eco Environmental Sciences | Zhang B.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Environmental Earth Sciences | Year: 2016

Understanding topographic effects on surface air temperature (SAT) is essential in developing an accurate prediction model in complex mountain environment. A nonlinear topographic regression model is developed to predict the spatial SAT pattern using latitude, elevation, slope, and aspect. Monthly SAT data have been collected from 14 meteorological stations between 1960 and 2010 in the Daqing Mountains of China. Topographic data are acquired from a 30 m resolution digital elevation model of the study region. Results show that: (1) the SAT models are able to explain 89–95.8 % of the spatial variation in different months. Elevation has the strongest effect on the SAT variation in all months (average 84.78 %). (2) The combined contribution of slope and aspect to SAT variations is larger (average 9.14 %) than that of latitude (average 6.07 %). (3) The combined effect of slope and aspect on SAT variations is higher in winter than in summer. The introduction of slope and aspect optimizes the SAT modeling in different months. In further studies, the accuracy of SAT model might be improved by introducing alternative topographic factors to capture the vegetation and weather condition. © 2016, Springer-Verlag Berlin Heidelberg.

Ye J.,Chinese Institute of Urban Environment | Rensing C.,University of Arizona | Rosen B.P.,Florida International University | Zhu Y.-G.,Chinese Institute of Urban Environment | Zhu Y.-G.,CAS Research Center for Eco Environmental Sciences
Trends in Plant Science | Year: 2012

Arsenic (As) is a ubiquitous element that is widespread in the environment and causes numerous health problems. Biomethylation of As has implications for its mobility and toxicity. Photosynthetic organisms may play a significant role in As geochemical cycling by methylating it to different As species, but little is known about the mechanisms of methylation. Methylated As species have been found in many photosynthetic organisms, and several arsenite S-adenosylmethionine (SAM) methyltransferases have been characterized in cyanobacteria and algae. However, higher plants may not have the ability to methylate As. Instead, methylated arsenicals in plants probably originate from microorganisms in soils and the rhizosphere. Here, we propose possible approaches for developing 'smart' photosynthetic organisms with an enhanced and sensitive biomethylation capacity for bioremediation and safer food. © 2011 Elsevier Ltd.

Zhang T.,King Abdullah University of Science and Technology | Li W.,CAS Research Center for Eco Environmental Sciences | Croue J.-P.,King Abdullah University of Science and Technology
Applied Catalysis B: Environmental | Year: 2012

Oxalate is usually used as a refractory model compound that cannot be effectively removed by ozone and hydroxyl radical oxidation in water. In this study, we found that ceria supported CuO significantly improved oxalate degradation in reaction with ozone. The optimum CuO loading amount was 12%. The molar ratio of oxalate removed/ozone consumption reached 0.84. The catalytic ozonation was most effective in a neutral pH range (6.7-7.9) and became ineffective when the water solution was acidic or alkaline. Moreover, bicarbonate, a ubiquitous hydroxyl radical scavenger in natural waters, significantly improved the catalytic degradation of oxalate. Therefore, the degradation relies on neither hydroxyl radical oxidation nor acid assistance, two pathways usually proposed for catalytic ozonation. These special characters of the catalyst make it suitable to be potentially used for practical degradation of refractory hydrophilic organic matter and compounds in water and wastewater. With in situ characterization, the new surface Cu(II) formed from ozone oxidation of the trace Cu(I) of the catalyst was found to be an active site in coordination with oxalate forming multi-dentate surface complex. It is proposed that the complex can be further oxidized by molecular ozone and then decomposes through intra-molecular electron transfer. The ceria support enhanced the activity of the surface Cu(I)/Cu(II) in this process. © 2012 Elsevier B.V.

Luo L.,Nanjing University of Aeronautics and Astronautics | Shen K.,Nanjing University of Aeronautics and Astronautics | Xu Q.,Nanjing Southeast University | Zhou Q.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Journal of Alloys and Compounds | Year: 2013

Multiferroic Co substituted BiFeO3 (BiFe0.95Co 0.05O3) compound was synthesized by complex sol-gel method and its potential application as an efficient magnetic adsorbent in sorption removal of organic contaminants (like Rhodamine B as a model compound) was investigated. The XRD, Raman, and PPMS measurement revealed that Co substituted BiFeO3 enhances magnetic properties dramatically at room temperature without inducing any impurity phase. This aspect is very useful for many applications of Co substituted BiFeO3 especially in magnetic separation of this catalyst after its utilization in water purification. The adsorption kinetics, isotherm, thermodynamic as well as the possible sorption mechanism was studied through batch experiments. Almost no negative effect on the sorption performance (i.e. the sorption rate and saturated sorption capacity) was found after substitution of Co in BiFeO3. In addition, this substitution give rise to much higher coercive force of BiFe 0.95Co0.05O3 which can be recycled more easily by magnetic separation technology. © 2012 Elsevier B.V. All rights reserved.

Blanckaert K.,Ecole Polytechnique Federale de Lausanne | Blanckaert K.,Technical University of Delft | Blanckaert K.,CAS Research Center for Eco Environmental Sciences | De Vriend H.J.,Technical University of Delft
Journal of Geophysical Research: Earth Surface | Year: 2010

Despite the rapid evolution of computational power, simulation of meander dynamics by means of reduced and computationally less expensive models remains practically relevant for investigation of large-scale and long-term processes, probabilistic predictions, or rapid assessments. Existing meander models are invariantly based on the assumptions of mild curvature and slow curvature variations and fail to explain processes in the high-curvature range. This article proposes a nonlinear model for meander hydrodynamics without curvature restrictions. It provides the distribution of the main flow, the magnitude of the secondary flow, the direction of the bed shear stress, and the curvature-induced additional energy losses. It encompasses existing mild curvature models, remains valid for straight flow, and agrees satisfactorily with experimental data from laboratory experiments under conditions that are more demanding than sharp natural river bends. The proposed model reveals the mechanisms that drive the velocity redistribution in meander bends and their dependence on the river's roughness Cf, the flow depth H, the radius of curvature R, the width B, and bathymetric variations. It identifies C f -1H/R as the major control parameter for meander hydrodynamics in general and the relative curvature R/B for sharp curvature effects. Both parameters are small in mildly curved bends but O(1) in sharply curved bends, resulting in significant differences in the flow dynamics. Streamwise curvature variations are negligible in mildly curved bends, but they are the major mechanisms for velocity redistribution in sharp bends. Nonlinear feedback between the main and secondary flow also plays a dominant role in sharp bends: it increases energy losses and reduces the secondary flow, the transverse bed slope, and the velocity redistribution. Copyright © 2010 by the American Geophysical Union.

Veresoglou S.D.,Free University of Berlin | Chen B.,CAS Research Center for Eco Environmental Sciences | Rillig M.C.,Free University of Berlin
Soil Biology and Biochemistry | Year: 2012

Nitrogen is a major nutrient that frequently limits primary productivity in terrestrial ecosystems. Therefore, the physiological responses of plants to soil nitrogen (N) availability have been extensively investigated, and the study of the soil N-cycle has become an important component of ecosystem ecology and biogeochemistry. The bulk of the literature in these areas has, however, overlooked the fact that most plants form mycorrhizal associations, and that nutrient uptake is therefore mediated by mycorrhizal fungi. It is well established that ecto- and ericoid mycorrhizas influence N nutrition of plants, but roles of arbuscular mycorrhizas in N nutrition are less well established; perhaps even more importantly, current conceptual models ignore possible influences of arbuscular mycorrhizal (AM) fungi on N-cycling processes. We review evidence for the interaction between the AM symbiosis with microbes and processes involved in soil N-cycling. We show that to date investigations have rather poorly addressed such interactions and discuss possible reasons for this. We outline mechanisms that could potentially operate with regards to AM fungal - N-cycling interactions, discuss experimental designs aimed at studying these, and conclude by pointing out priorities for future research. © 2011 Elsevier Ltd.

Li J.,Shanxi University | Zhou X.,Shanxi University | Yan J.,Shanxi University | Li H.,Shanxi University | He J.,CAS Research Center for Eco Environmental Sciences
Applied Soil Ecology | Year: 2015

The aim of this study was to evaluate the influence of reclaimed scenarios on soil enzyme activities and microbial community in a reclaimed surface coal mine on the Northwest Loess Plateau of China. Soil samples were collected from a bare land (CK), and a plantation (PL) and four mixed forests (MF1-4). Soil physicochemical characteristics, four enzyme activities and microbial abundance and T-RFLP (terminal restriction fragment length polymorphism) profiles were measured. Effects of reclaimed scenarios on soil nutrients content, enzyme activities and microbial community were pronounced. Soil organic carbon could be well used to predict the major differences in enzyme activities, and microbial abundance and composition. Soil enzyme activities were more significantly correlated with fungal abundance than bacterial and archaeal ones. The higher soil nutrient content, enzyme activities, and microbial abundance and diversity were from mixed forests and the lowest ones were from CK, which suggested mixed forests would be feasible scenarios in semi-arid Loess Plateau. Soil bacteria, archaea and fungi evolved with reclaimed process, but the influences of reclaimed scenarios on each domain of microbial abundance, diversity and composition were different. These findings suggested that soil bacteria, archaea and fungi play different ecological roles during restoration process. © 2014 Elsevier B.V.

Li H.,CAS Research Center for Eco Environmental Sciences | Zhang Y.,CAS Research Center for Eco Environmental Sciences | Yang M.,CAS Research Center for Eco Environmental Sciences | Kamagata Y.,Japan National Institute of Advanced Industrial Science and Technology
Frontiers of Environmental Science and Engineering in China | Year: 2013

The effects of hydraulic retention time (HRT) on the nitrification activities and population dynamics of a conventional activated sludge system fed with synthetic inorganic wastewater were investigated over a period of 260 days. When the HRT was gradually decreased from 30 to 5 h, the specific ammonium-oxidizing rates (SAOR) varied between 0. 32 and 0. 45 kg NH4 + -N (kg mixed liquor suspended solids (MLSS)·d)-1, and the specific nitrate-forming rates (SNFR) increased from 0. 11 to 0. 50 kg NO3 - -N (kg MLSS·d)-1, showing that the decrease in HRT led to a significant increase in the nitrite oxidation activity. According to fluorescence in situ hybridization (FISH) analysis results, the proportion of ammonia-oxidizing bacteria (AOBs) among the total bacteria decreased from 33% to 15% with the decrease in HRT, whereas the fraction of nitrite-oxidizing bacteria (NOBs), particularly the fast-growing Nitrobacter sp., increased significantly (from 4% to 15% for NOBs and from 1. 5% to 10. 6% for Nitrobacter sp.) with the decrease in HRT, which was in accordance with the changes in SNFR. A short HRT favored the relative growth of NOBs, particularly the fast-growing Nitrobacter sp., in the conventional activated sludge system. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Feng X.M.,CAS Research Center for Eco Environmental Sciences | Sun G.,U.S. Department of Agriculture | Fu B.J.,CAS Research Center for Eco Environmental Sciences | Su C.H.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Hydrology and Earth System Sciences | Year: 2012

The general relationships between vegetation and water yield under different climatic regimes are well established at a small watershed scale in the past century. However, applications of these basic theories to evaluate the regional effects of land cover change on water resources remain challenging due to the complex interactions of vegetation and climatic variability and hydrologic processes at the large scale. The objective of this study was to explore ways to examine the spatial and temporal effects of a large ecological restoration project on water yield across the Loess Plateau region in northern China. We estimated annual water yield as the difference between precipitation input and modelled actual evapotranspiration (ET) output. We constructed a monthly ET model using published ET data derived from eddy flux measurements and watershed streamflow data. We validated the ET models at a watershed and regional levels. The model was then applied to examine regional water yield under land cover change and climatic variability during the implementation of the Grain-for-Green (GFG) project during 1999-2007. We found that water yield in 38% of the Loess Plateau area might have decreased (1-48 mm per year) as a result of land cover change alone. However, combined with climatic variability, 37% of the study area might have seen a decrease in water yield with a range of 1-54 mm per year, and 35% of the study area might have seen an increase with a range of 1-10 mm per year. Across the study region, climate variability masked or strengthened the water yield response to vegetation restoration. The absolute annual water yield change due to vegetation restoration varied with precipitation regimes with the highest in wet years, but the relative water yield changes were most pronounced in dry years. We concluded that the effects of land cover change associated with ecological restoration varied greatly over time and space and were strongly influenced by climatic variability in the arid region. The current regional vegetation restoration projects have variable effects on local water resources across the region. Land management planning must consider the influences of spatial climate variability and long-term climate change on water yield to be more effective for achieving environmental sustainability. © Author(s) 2012.

Chen X.,CAS Research Center for Eco Environmental Sciences | Chen X.,University of Chinese Academy of Sciences | Zhang L.-M.,CAS Research Center for Eco Environmental Sciences | Shen J.-P.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Biology and Fertility of Soils | Year: 2011

Nitrification is essential to the nitrogen cycle in paddy soils. However, it is still not clear which group of ammonia-oxidizing microorganisms plays more important roles in nitrification in the paddy soils. The changes in the abundance and composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated by real-time PCR, terminal restriction fragment length polymorphism, and clone library approaches in an acid red paddy soil subjected to long-term fertilization treatments, including treatment without fertilizers (CT); chemical fertilizer nitrogen (N); N and potassium (NK); N and phosphorus (NP); N, P, and K (NPK); and NPK plus recycled crop residues (NPK+C). The AOA population size in NPK+C was higher than those in CT, while minor changes in AOB population sizes were detected among the treatments. There were also some changes in AOA community composition responding to different fertilization treatments. Still few differences were detected in AOB community composition among the treatments. Phylogenetic analysis showed that the AOA sequences fell into two main clusters: cluster A and cluster soil/sediment. The AOB composition in this paddy soil was dominated by Nitrosospira cluster 12. These results suggested that the AOA were more sensitive than AOB to different fertilization treatments in the acid red paddy soil. © 2011 Springer-Verlag.

Wang M.,CAS Research Center for Eco Environmental Sciences | Bai Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Chen W.,CAS Research Center for Eco Environmental Sciences | Markert B.,International Institute of Higher Education, Zittau | And 2 more authors.
Environmental Pollution | Year: 2012

Ecological risks of heavy metals in urban soils were evaluated using Beijing, China as an example. Cadmium, Cu, Zn, Pb, Cr and Ni contents of 233 surface soils sampled by 1 min latitude × 1 min longitude grid were used to identify their spatial distribution patterns and potential emission sources. Throughout the city, longer the duration of urbanization greater was the accumulations of heavy metals especially, Cd, Cu, Pb, and Zn. The soil Zn mainly came from the wears of vehicular tires. Point source emissions of heavy metals were few and far in the downwind south-east quadrant of Beijing. The calculated risk indices showed potential median eco-risks in the ancient central city. No potential high eco-risk due to soil-borne heavy metals was found. The potential medium eco-risk areas in Beijing would expand from the initial 24 to 110 km 2 if soil pH were to reduce by 0.5 units in anticipation. © 2011 Elsevier Ltd. All rights reserved.

Wang M.,CAS Research Center for Eco Environmental Sciences | Markert B.,International Institute of Higher Education, Zittau | Chen W.,CAS Research Center for Eco Environmental Sciences | Peng C.,CAS Research Center for Eco Environmental Sciences | Ouyang Z.,CAS Research Center for Eco Environmental Sciences
Environmental Monitoring and Assessment | Year: 2012

In order to evaluate the current state of the environmental quality of soils in Beijing, we investigated contents of 14 metals in Beijing urban soils inside the 5th ring road by even grids sampling. Statistic analyses were conducted to identify possible heavy metal pollutants, as well as the effects of land uses on their accumulation. Our results revealed that the urban soils in Beijing were contaminated by Cd, Pb, Cu, and Zn. Land uses and urbanization ages affected the accumulation of the four heavy metals in soils significantly. Soils in industrial areas have the highest average Cu and Zn contents, while Pb contents in park areas and Cd in agricultural areas are the highest. The accumulations of Pb and Zn in urban soils increase significantly with sampling plots approaching the city center. And Pb, Cd, and Zn contents in soils in traffic areas also tend to increase in the city center. However, residential areas have the lowest contents of all the four heavy metals. © Springer Science+Business Media B.V. 2012.

Wang X.,CAS Research Center for Eco Environmental Sciences | Liu J.,CAS Research Center for Eco Environmental Sciences | Ren N.-Q.,Harbin Institute of Technology | Duan Z.,AECOM Technology Corporation
Bioresource Technology | Year: 2012

Stringent new legislation for wastewater treatment plants (WWTPs) is currently motivating innovation and optimization of wastewater treatment technologies. Evaluating the environmental performance of a wastewater treatment system is a necessary precursor before proposing implementation of WWTPs designed to address the global requirements for reduced resource use, energy consumption and environmental emissions. However, developing overly-sophisticated treatment methods may lead to negative environmental effects. This study was conducted to employ a process modeling approach from a life cycle perspective to construct and evaluate six anaerobic/anoxic/oxic wastewater treatment systems that include a water line, sludge line and bioenergy recovery system and was designed to meet different treatment standards in China. The results revealed that improved treatments optimized for local receiving watercourses can be realized at the cost of higher resource consumption and greenhouse gas emissions. Optimal Scenarios were also identified from different positive perspectives. © 2012 Elsevier Ltd.

Feng Z.,CAS Research Center for Eco Environmental Sciences | Hu E.,CAS Research Center for Eco Environmental Sciences | Wang X.,CAS Research Center for Eco Environmental Sciences | Jiang L.,CAS Research Center for Eco Environmental Sciences | Liu X.,China Agricultural University
Environmental Pollution | Year: 2015

Ground-level ozone (O3) pollution has become one of the top environmental issues in China, especially in those economically vibrant and densely populated regions. In this paper, we reviewed studies on the O3 concentration observation and O3 effects on food crops throughout China. Data from 118 O3 monitoring sites reported in the literature show that the variability of O3 concentration is a function of geographic location. The impacts of O3 on food crops (wheat and rice) were studied at five sites, equipped with Open Top Chamber or O3-FACE (free-air O3 concentration enrichment) system. Based on exposure concentration and stomatal O3 flux-response relationships obtained from the O3-FACE experimental results in China, we found that throughout China current and future O3 levels induce wheat yield loss by 6.4-14.9% and 14.8-23.0% respectively. Some policies to reduce ozone pollution and impacts are suggested. © 2015 Elsevier Ltd. All rights reserved.

Han Y.,Beijing Forestry University | Fan Y.,Chinese Academy of Agricultural Sciences | Yang P.,China Agricultural University | Wang X.,CAS Research Center for Eco Environmental Sciences | And 4 more authors.
Geoderma | Year: 2014

This study provides a new understanding to sources of nitrogen (N), and may serve as a foundation for further exploration of anthropogenic effects on N inputs. Estimation of net anthropogenic nitrogen inputs (NANI) was based on an inventory of atmospheric N deposition, N fertilizer use, N in human food and animal feed, seeding N and N fixation. This study took a step forward to calculate NANI in detail on a regional scale, and analyzed its temporal variations and geographic differences. Over the past 28years, NANI increased significantly in Mainland China, from 2360kgNkm-2yr-1 to 5013kgNkm-2yr-1. On a geographical basis, NANI was higher in southeast where China's eight major watersheds are located than in northwest, and the largest NANI, 26160kgNkm-2yr-1, appeared in Shanghai. The administrative regions corresponding to Haihe watershed, Huaihe watershed and Tai lake watershed have the largest NANI. N input of fertilizer is the largest source of NANI, followed by atmospheric N deposition and N fixation. The primary factor in relation to the change in NANI is total population density, followed by cultivated land area and total grain yield. In those densely populated large cities and watersheds, reasonably allocating the social resources to reduce the existing population density is the most effective way to address the problem of high N inputs, while in those agriculture-dominated regions and watersheds, the most effective way for reducing NANI is to improve fertilizer utilization efficiency in agriculture. © 2013 Elsevier B.V.

Ma C.,CAS Research Center for Eco Environmental Sciences | Xue W.,CAS Research Center for Eco Environmental Sciences | Li J.,CAS Research Center for Eco Environmental Sciences | Xing W.,China University of Petroleum - East China | Hao Z.,CAS Research Center for Eco Environmental Sciences
Green Chemistry | Year: 2013

A series of ordered mesoporous carbon (OMC)-supported Au catalysts were successfully prepared by nano-replication, followed by colloidal gold deposition method. Structural analysis showed that the mesopore sizes of the catalysts can be tuned controllably in the range of 3.2-7.6 nm by adjusting the dosage of boric acid used to prepare the carbon supports. TEM observations revealed that the Au nanoparticles were dispersed uniformly in the mesopore channels of the carbon supports. These Au/OMC catalysts were tested for the aerobic oxidation of glucose to produce gluconic acid at 40°C and pH 9. As demonstrated by the structural analysis and reaction results, the activities of these catalysts were closely related to their mesopore sizes. The catalyst with a mesopore size of 5.4 nm exhibited a superior catalytic activity with a TOF of 4.308 mol glucose molAu -1 s-1 to the catalysts reported previously by other researchers. This high activity was mainly ascribed to its unique structure, consisting of 5.4 nm mesopore channels incorporated with 3.3 nm Au nanoparticles, which facilitates contact between glucose molecules and Au nanoparticles. Besides, the abundant active oxygen species existing on this catalyst surface also promote glucose oxidation. © 2013 The Royal Society of Chemistry.

Wang S.,CAS Research Center for Eco Environmental Sciences | Wang S.,University of Science and Technology Beijing | Wang Y.,CAS Research Center for Eco Environmental Sciences | Feng X.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2011

With the rapid development of ammonia-synthesizing industry, the ammonia-nitrogen pollution in wetlands acting as the sink of point and diffuse pollution has been increased dramatically. Most of ammonia-nitrogen is oxidized at least once by ammonia-oxidizing prokaryotes to complete the nitrogen cycle. Current research findings have expanded the known ammonia-oxidizing prokaryotes from the domain Bacteria to Archaea. However, in the complex wetlands environment, it remains unclear whether ammonia oxidation is exclusively or predominantly linked to Archaea or Bacteria as implied by specific high abundance. In this research, the abundance and composition of Archaea and Bacteria in sediments of four kinds of wetlands with different nitrogen concentration were investigated by using quantitative real-time polymerase chain reaction, cloning, and sequencing approaches based on amoA genes. The results indicated that AOA distributed widely in wetland sediments, and the phylogenetic tree revealed that archaeal amoA functional gene sequences from wetlands sediments cluster as two major evolutionary branches: soil/sediment and sediment/water. The bacteria functionally dominated microbial ammonia oxidation in different wetlands sediments on the basis of molecule analysis, potential nitrification rate, and soil chemistry. Moreover, the factors influencing AOA and AOB abundances with environmental indicator were also analyzed, and the results addressed the copy numbers of archaeal and bacterial amoA functional gene having the higher correlation with pH and ammonia concentration. The pH had relatively great negative impact on the abundance of AOA and AOB, while ammonia concentration showed positive impact on AOB abundance only. These findings could be fundamental to improve understanding of the importance of AOB and AOA in nitrogen and other nutrients cycle in wetland ecosystems. © 2011 Springer-Verlag.

Qian H.,University of Illinois at Springfield | Chen S.,Nanjing Institute of Environmental Sciences | Chen S.,CAS Research Center for Eco Environmental Sciences | Mao L.,CAS Institute of Botany | And 2 more authors.
Global Ecology and Biogeography | Year: 2013

Aim: Ecologists have generally agreed that β-diversity is driven at least in part by ecological processes and mechanisms of community assembly and is a key determinant of global patterns of species richness. This idea has been challenged by a recent study based on an individual-based null model approach, which aims to account for the species pool. The goal of the present study is twofold: (1) to analyse data sets from different parts of the world to determine whether there are significant latitude-β-diversity gradients after accounting for the species pool, and (2) to evaluate the validity of the null model. Location: Global. Methods: A total of 257 forest plots, each being 0.1 ha in size and having 10 0.01-ha subplots, were used. We conducted four sets of analyses. A modified version of Whittaker's β-diversity index was used to quantify β-diversity for each forest plot. A randomization procedure was used to determine expected β-diversity. Results: The number of individuals per species, which characterizes species abundance distribution, alone explains 56.8-84.2% of the variation in observed β-diversity. Species pool (γ-diversity) explained only an additional 2.6-15.2% of the variation in observed β-diversity. Latitude explains 18.6% of the variation in raw β deviation in Gentry's global data set, and explains 11.0-11.6% of the variation in standardized β deviation in the global and three regional analyses. Latitude explains 33.2-46.2% of the variation in the number of individuals per species. Main conclusions: Species abundance distribution, rather than species pool size, plays a key role in driving latitude-β-diversity gradients for β-diversity in local forest communities. The individual-based null model is not a valid null model for investigating β-diversity gradients driven by mechanisms of local community assembly because the null model incorporates species abundance distributions, which are driven by mechanisms of local community assembly and in turn generate β-diversity gradients. © 2012 John Wiley & Sons Ltd.

Sun G.-X.,CAS Research Center for Eco Environmental Sciences | Liu X.,CAS Research Center for Eco Environmental Sciences | Liu X.,University of Aberdeen | Williams P.N.,CAS Research Center for Eco Environmental Sciences | And 3 more authors.
Environmental Science and Technology | Year: 2010

Selenium, an essential micronutrient for humans, is insufficient in dietary intake for millions of people worldwide. Rice as the most popular staple food in the world is one of the dominant selenium (Se) sources for people. The distribution and translocation of Se from soil to grain were investigated in a Se-rich environment in this study. The Se levels in soils ranged widely from 0.5 to 47.7 mg kg-1. Selenium concentration in rice bran was 1.94 times higher than that in corresponding polished rice. The total Se concentrations in the rice fractions were in the following order: straw > bran > whole grain > polished rice > husk. Significant linear relationships between different rice fractions were observed with each other, and Se in the soil has a linear relationship with different rice fractions as well. Se concentration in rice can easily be predicted by soil Se concentrations or any rice fractions and vice versa according to their linear relationships. In all rice samples for Se speciation, SeMet was the major Se species, followed by MeSeCys and SeCys. The average percentage for SeMet (82.9%) and MeSeCys (6.2%) was similar in the range of total Se from 2.2 to 8.4 mg kg-1 tested. The percentage of SeCys decreased from 6.3 to 2.8%, although its concentration elevated with the increase in total Se in rice. This could be due to the fact that SeCys is the precursor for the formation of other organic Se compounds. The information obtained may have considerable significance for assessing translocation and accumulation of Se in plant. © 2010 American Chemical Society.

Li J.,Beijing Normal University | Wang Z.,CAS Research Center for Eco Environmental Sciences | Ma M.,CAS Research Center for Eco Environmental Sciences | Peng X.,CAS Guangzhou Institute of Geochemistry
Bulletin of Environmental Contamination and Toxicology | Year: 2010

A battery of in vitro recombinant yeast bioassays was conducted to assess the estrogen receptor, androgen receptor, progesterone receptor and thyroid receptor ant/agonistic activities of effluents collected from Datansha wastewater treatment plant (WWTP), furthermore to evaluate the removal efficiencies of endocrine disrupting chemicals in the WWTP. The results showed that estrogenic, anti-androgenic, anti-progesteronic and anti-thyroidic activities were observed in influent. The removal efficiencies of these compounds were more than 80%, which suggested that the present wastewater treatment processes were good enough to remove most of all kinds of endocrine disruption chemicals. © Springer Science+Business Media, LLC 2010.

Luo Y.,CAS Research Center for Eco Environmental Sciences | Wang X.,CAS Research Center for Eco Environmental Sciences | Zhang X.,The Nature Conservancy China Program | Booth T.H.,CSIRO | Lu F.,CAS Research Center for Eco Environmental Sciences
Forest Ecology and Management | Year: 2012

Using a new above-ground biomass (AGB) and below-ground biomass (BGB) dataset of 649 paired observations from China's forests, root:shoot ratios (RSRs) and BGB-AGB models (where BGB is a function of AGB) were analyzed by forest groups, phylogenies, leaf habits and forest origins. RSRs were lower in coniferous forests than broadleaved forests. RSRs were also lower in evergreen forests than deciduous forests, and lower in plantations than natural forests. Decreasing RSRs with mean annual temperature (MAT) were found in the whole dataset as well as in three separate forest types (coniferous forests, deciduous broadleaved forests and evergreen broadleaved forests) and three genera (Cunninghamia, Pinus and Quercus). However, RSRs showed different trends with mean annual precipitation (MAP) across different groups including: a U-shaped pattern for coniferous forests, Larix forest and Pinus forest covering wide MAP ranges; a decreasing trend for deciduous broadleaved forests and Quercus forest covering ranges with low MAP; and no trend for evergreen broadleaved forest and Cunninghamia forest covering ranges with high MAP. Our results support the existence of different AGB-BGB allocation strategies for optimum tree growth which are in line with optimal partitioning theory applied at a broad scale. © 2012 Elsevier B.V.

Lan H.,CAS Research Center for Eco Environmental Sciences | Wang A.,Beijing Jiaotong University | Liu R.,CAS Research Center for Eco Environmental Sciences | Liu H.,CAS Research Center for Eco Environmental Sciences | Qu J.,CAS Research Center for Eco Environmental Sciences
Journal of Hazardous Materials | Year: 2015

Fe2O3 supported on activated carbon fiber (Fe2O3/ACF) was prepared via an impregnation method and characterized by X-ray diffraction, scanning electron microscopy and BET analysis. The results indicated that Fe2O3 with small particle size was highly dispersed on the surface of the ACF and the introduction of Fe2O3 did not change the ACF pore structure. Fe2O3/ACF exhibited a higher Fenton efficiency for the degradation of acid red B (ARB), especially under simulated solar irradiation. Complete decoloration of the ARB solution and 43% removal of TOC could be achieved within 200min under optimal conditions. It was verified that more OH radicals were generated in the photo-assisted Fenton process and involved as active species in ARB degradation. FTIR analysis indicated that the degradation of ARB was initiated through the cleavage of NN, followed by hydroxylation and opening of phenyl rings to form aliphatic acids, and further oxidation of aliphatic acids would produce CO2 and H2O. Moreover, Fe2O3/ACF maintained its activity after being reused 4 times and the release of iron from the catalyst was found to be insignificant during the Fenton and photo-Fenton processes, indicating that Fe2O3/ACF had good long-term stability. © 2014.

Yin R.,CAS Research Center for Eco Environmental Sciences | Liu S.,CAS Research Center for Eco Environmental Sciences | Zhao C.,CAS Research Center for Eco Environmental Sciences | Lu M.,CAS Research Center for Eco Environmental Sciences | And 3 more authors.
Analytical Chemistry | Year: 2013

Acrolein (Acr), a ubiquitous environmental pollutant, can react directly with genomic DNA to form mutagenic adducts without undergoing metabolic activation. To sensitively and accurately quantify Acr-DNA adducts (including structural isomers and stereoisomers) in human leukocytes, we developed an enhanced stable isotope dilution ultrahigh performance liquid chromatography (UHPLC)-tandem mass spectrometry (MS/MS) method using ammonium bicarbonate (NH4HCO3), which is thermally unstable and degrades readily to carbon dioxide and ammonia in heated gas phase. Interestingly, ammonium bicarbonate (as an additive to the mobile phase) not only improves the protonation of AcrdG adducts but also suppresses the formation of MS signal-deteriorating metal-AcrdG complexes during electrospray ionization, leading to the enhancement of their MS detection by 2.3-8.7 times. In contrast, routinely used ammonium salts (ammonium acetate and ammonium formate) and formic acid do not show similar enhancement. The developed method is potentially useful for enhancing ESI-MS detection of other modified 2′- deoxyribonucleosides that have difficulty in protonation and may form excess metal complexes during electrospray ionization. The limits of detection (LODs, S/N = 3) are estimated to be about 40-80 amol. By the use of the developed method, we found that the Acr adducts of three nucleotides (dG, dA, and dC) can be detected in human leukocytes. In addition to the known γ-AcrdG, α-AcrdA is also identified as an Acr-adduct of high abundance (2.5-20 adducts per108 nts). © 2013 American Chemical Society.

Zhang S.,CAS Research Center for Eco Environmental Sciences | Zhang Y.,CAS Research Center for Eco Environmental Sciences | Ma K.,CAS Research Center for Eco Environmental Sciences
Journal of Ecology | Year: 2016

In the past, it was widely accepted that herbivory decreased with latitude. However, several empirical studies have failed to support this hypothesis, leading to strong debate. In addition to providing a quantitative assessment of the latitudinal gradient in herbivory, our study aims to provide new information about the role of climatic factors in shaping the latitudinal gradient in herbivory. Through the collection and analysis of published data on herbivory, we tested the latitudinal herbivory hypothesis (LH hypothesis) and the relationship of temperature and precipitation to herbivory. Based on 1890 data points distributed world-wide from more than 1000 plant species, our results show that herbivory decreased with latitude and increased with temperature only in the Northern Hemisphere. In contrast, in the Southern Hemisphere, herbivory did not have a relationship with latitude and tended to decrease with temperature. Synthesis. This study shows the LH hypothesis is supported only in the Northern Hemisphere and highlights the importance of temperature in explaining the pattern of herbivory at the global scale. These possible hemispheric asymmetries in herbivory should not be overlooked in future studies. © 2016 The Authors. Journal of Ecology © 2016 British Ecological Society

Zhang T.,King Abdullah University of Science and Technology | Li W.,CAS Research Center for Eco Environmental Sciences | Croue J.-P.,King Abdullah University of Science and Technology
Environmental Science and Technology | Year: 2011

The cerium supported palladium oxide (PdO/CeO 2) at a low palladium loading was found very effective in catalytic ozonation of oxalate, a probe compound that is difficult to be efficiently degraded in water with hydroxyl radical oxidation and one of the major byproducts in ozonation of organic matter. The oxalate was degraded into CO 2 during the catalytic ozonation. The molar ratio of oxalate degraded to ozone consumption increased with increasing catalyst dose and decreasing ozone dosage and pH under the conditions of this study. The maximum molar ratio reached around 1, meaning that the catalyst was highly active and selective for oxalate degradation in water. The catalytic ozonation, which showed relatively stable activity, does not promote hydroxyl radical generation from ozone. Analysis with ATR-FTIR and in situ Raman spectroscopy revealed that 1) oxalate was adsorbed on CeO 2 of the catalyst forming surface complexes, and 2) O 3 was adsorbed on PdO of the catalyst and further decomposed to surface atomic oxygen (*O), surface peroxide (*O 2), and O 2 gas in sequence. The results indicate that the high activity of the catalyst is related to the synergetic function of PdO and CeO 2 in that the surface atomic oxygen readily reacts with the surface cerium-oxalate complex. This kind of catalytic ozonation would be potentially effective for the degradation of polar refractory organic pollutants and hydrophilic natural organic matter. © 2011 American Chemical Society.

Wang J.,CAS Nanjing Institute of Geography and Limnology | Wang J.,CAS Research Center for Eco Environmental Sciences | Shen J.,CAS Nanjing Institute of Geography and Limnology | Wu Y.,CAS Nanjing Institute of Soil Science | And 7 more authors.
ISME Journal | Year: 2013

Increasing evidence has emerged for non-random spatial distributions of microbes, but knowledge of the processes that cause variation in microbial assemblage among ecosystems is lacking. For instance, some studies showed that deterministic processes such as habitat specialization are important, while other studies hold that bacterial communities are assembled by stochastic forces. Here we examine the relative influence of deterministic and stochastic processes for bacterial communities from subsurface environments, stream biofilm, lake water, lake sediment and soil using pyrosequencing of the 16S ribosomal RNA gene. We show that there is a general pattern in phylogenetic signal in species ecological niches across recent evolutionary time for all studied habitats, enabling us to infer the influences of community assembly processes from patterns of phylogenetic turnover in community composition. The phylogenetic dissimilarities among-habitat types were significantly higher than within them, and the communities were clustered according to their original habitat types. For communities within-habitat types, the highest phylogenetic turnover rate through space was observed in subsurface environments, followed by stream biofilm on mountainsides, whereas the sediment assemblages across regional scales showed the lowest turnover rate. Quantifying phylogenetic turnover as the deviation from a null expectation suggested that measured environmental variables imposed strong selection on bacterial communities for nearly all sample groups. For three sample groups, spatial distance reflected unmeasured environmental variables that impose selection, as opposed to spatial isolation. Such characterization of spatial and environmental variables proved essential for proper interpretation of partial Mantel results based on observed beta diversity metrics. In summary, our results clearly indicate a dominant role of deterministic processes on bacterial assemblages and highlight that bacteria show strong habitat associations that have likely emerged through evolutionary adaptation. © 2013 International Society for Microbial Ecology All rights reserved.

He G.,CAS Research Center for Eco Environmental Sciences | Lu Y.,CAS Research Center for Eco Environmental Sciences
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2011

Abstract; With an increase in environmentally harmful accidents and amplification in their impact, the concept of environmental risk assessment and management has been formally acknowledged and applied for the last 30 years. As environmental risks have become more complex and relevant scientific knowledge has increased in its degree of detail, guidelines for the implementation of existing environmental risk assessment and risk management frameworks are needed. More and more international organizations and countries have developed and applied approaches to environmental risk assessment and risk management. The United States and Canada are two pioneers in the field. Although China faces various environmental risks and environmental accidents in the midst of its rapid social, economic and political transitions, for a long time, it has been lacking an environmental management system. After a series of accidents, especially SARS in 2003 and water pollution of Songhuajiang River in 2005, the setting-up of a national risk management system in China was initiated. However, it has not been systematically developed and falls short of guidelines for its implementation as well as practical and suitable methods for environmental risk assessment and risk management. With the aim of learning from the experiences of the two pioneers of environmental risk assessment and risk management, the authors conducted a literature and document review, email exchanges and telephone interviews, and applied comparative analysis methods from February to October 2009, focusing on experiences of environmental, ecological, and human health risk assessment and management methodology. This article reviews more than 50 sets of environmental, ecological and human health risk assessment and management approaches currently being applied by agencies of the United States and Canada. Out of them, 24 frameworks are selected and their characteristics are described. Among these, 10 frameworks are analyzed in detail. We compare their basis and limitations, strengths and weaknesses, their application to case studies, as well as specific issues addressed by the frameworks. Based on the above analysis, we identified seven common elements that should be included in an effective and comprehensive framework to assess environmental, human health and work-related health risks. The seven elements are; risk formulation, involvement of stakeholders in this process, risk communication to stakeholders, quantitative risk assessment, reiteration and evaluation of the process, decision-making based on sound science, and flexibility of the environmental and ecological risk assessment and management framework. Strategies to develop risk management objectives are also discussed based on the experiences in the United States and Canada. This study concludes that decision makers in China should foremost focus on the formulation of objectives for environmental and ecological risk management. Other concerns include a sound scientific basis for environmental and ecological risk management, encouragement of stakeholders' involvement and effective risk communication using multiple communication channels, and the application of suitable and practical approaches for Chinese environmental risk management. This conclusion leads to the above mentioned strategies with the help of which environmental authorities may effectively support decision making processes and may not be marginalized or isolated inthe process.

Di H.J.,Lincoln University at Christchurch | Cameron K.C.,Lincoln University at Christchurch | Sherlock R.R.,Lincoln University at Christchurch | Shen J.-P.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Journal of Soils and Sediments | Year: 2010

Purpose: Nitrous oxide (N2O) is a potent greenhouse gas and, in grazed grassland systems where animals graze outdoor pastures, most of the N2O is emitted from animal urine nitrogen (N) deposited during grazing. Recently, ammonia-oxidizing archaea (AOA) were found to be present in large numbers in soils as well in the ocean, suggesting a potentially important role for AOA, in addition to ammonia-oxidizing bacteria (AOB), in the nitrogen cycle. The relationship between N2O emissions and AOB and AOA populations is unknown. The objective of this study was to determine the quantitative relationship between N2O emissions and AOB and AOA populations in nitrogen-rich grassland soils. Materials and methods: We determined N2O emissions and the abundance and activity of AOB and AOA in four different soils as affected by the applications of animal urine N and dicyandiamide (DCD) as a nitrification inhibitor. Relationships were then determined between N2O emissions and the AOB and AOA populations. Results and discussion: Total N2O emissions from the urine N applied at 1,000 kg N ha-1 varied significantly in these soils, from 13.9 to 39.8 kg N2O-N ha-1. The DCD treatment reduced these N2O emissions to between 2.8 and 15.3 kg N2O-N ha-1. The average emission factor of the urine N (EF3) was 2.2% and this was decreased to 0.8%, representing a 64% reduction. Total N2O emissions were significantly related to the amoA gene copy numbers of the AOB population and to the amount of nitrate-N in the soil, but not related to the abundance of AOA. Conclusions: These results demonstrate that the N2O flux is mainly associated with the dynamics of the AOB population rather than the AOA in these nitrogen-rich grassland soils, and therefore, it is the AOB that should be the target of inhibition when mitigating N2O emissions using nitrification inhibitors. © 2010 Springer-Verlag.

Li K.,University of Chinese Academy of Sciences | Bai Z.,CAS Research Center for Eco Environmental Sciences | Zhang H.,University of Chinese Academy of Sciences
Extremophiles | Year: 2015

Pyrosequencing and quantitative polymerase chain reaction of small subunit rRNA genes were used to provide a comprehensive examination of bacterial, cyanobacterial, and eukaryotic communities in the biological soil crusts (BSCs) of Gurbantünggüt Desert sand dunes (China). Three succession stages were recognized based on the analyses of eukaryotic communities: a late succession stage of BSCs in a swale with eukaryotes mainly related to the Bryophyta clade, an initial succession stage in a slope with barely any eukaryotic phototrophic microorganisms detected, and an intermediate succession type detected from both the swale and slope BSCs dominated by the phylum Chlorophyta. Moreover, the cyanobacterial community dominated all of the BSCs (48.2–69.5 % of the total bacteria) and differed among the three succession stages: sequences related to Microcoleussteenstrupii and the genus Scytonema were abundant in the later succession stage, whereas both the initial and intermediate stages were dominated by Microcoleus vaginatus. Compared with swales, BSCs from slopes are exposed to a harsher environment, e.g., higher irradiance and lower water availability, and thus may be restricted from developing to a higher succession stage. Other disturbances such as wind and grazing may explain the different succession stages observed in swales or slopes. However, no clear differences were detected from non-phototrophic bacterial communities of the three succession stages, and sequences related to Alphaproteobacteria and Actinobacteria were most abundant in all the BSCs. The closest matches for the most frequent non-phototrophic bacterial genera were mainly derived from harsh environments, indicating the robustness of these genera. © 2014, Springer Japan.

Wang Y.,CAS Research Center for Eco Environmental Sciences | Wang Y.,Tsinghua University | Holler S.,Wuppertal Institute for Climate