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Liu Y.,Sichuan Agricultural University | Liu Y.,Chengdu Environmental Monitoring Center | Lin L.,Yaan Soil and Water Conservation Monitoring Substation | Jin Q.,Sichuan Agricultural University | Zhu X.,Sichuan Agricultural University
Environmental Progress and Sustainable Energy | Year: 2015

Advances in phytoremediation research require the selection of new hyperaccumulators or accumulators and investigations of their tolerance and accumulation of heavy metals. Two concentration gradient experiments (preliminary and verification), involving the same soil Cd concentrations (0, 25, 50, 75, 100, and 125 mg kg-1), were conducted to study Cd accumulation and tolerance in Capsella bursa-pastoris. In the preliminary and verification concentration gradient experiments, the Cd content in shoots of C. bursa-pastoris exceeded 100 mg kg-1 at a soil Cd concentration of 50 mg kg-1, and the maxima of Cd contents in shoots were 307.67 and 369.20 mg kg-1 at 125 mg kg-1 Cd in soil, respectively. The shoot bioconcentration factor of C. bursa-pastoris was greater than 1, but the translocation factor was less than 1.0 in the preliminary and verification concentration gradient experiments. In the verification concentration gradient experiment, the malondialdehyde content and the activities of superoxide dismutase, peroxidase, and catalase increased compared with the control. Therefore, C. bursa-pastoris is a Cd-accumulator with strong tolerance to Cd, and could be used to remediate Cd-contaminated farmland soil in winter. © 2014 American Institute of Chemical Engineers Environ Prog.

PubMed | Renmin University of China, Chengdu Environmental Monitoring Center, Tianjin University, CAS Institute of Tibetan Plateau Research and 2 more.
Type: | Journal: The Science of the total environment | Year: 2016

The Tibetan Plateau (TP) has been the subject of study on water circulation and global climate change. Given the environmental processes related to water outflows, there could be massive nutrient losses in the land surface of TP. In this study, we analyzed the nitrogen discharges of the major rivers flowing out of the TP based on the 5-year monitoring data. According to our calculation, the majority of nitrogen outflows were discharged through the upper Yangtze River and upper Huanghe River, representing ~29% and ~17% of total riverine outflows, respectively. In the entire nitrogen deficit in TP land surface, about 2.7 10(5)Mg/year was lost through riverine discharges. Due to the global warming, the changes of hydrologic processes in TP would possibly accelerate the riverine nitrogen outflows in the future.

Leng G.,Sichuan University | Lui G.,Chengdu Environmental Monitoring Center | Chen Y.,Chengdu Environmental Monitoring Center | Yin H.,Chengdu Environmental Monitoring Center | Dan D.,Sichuan University
Journal of Separation Science | Year: 2012

A simple, rapid, and efficient method, vortex-assisted extraction followed by dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in sediment samples prior to analysis by high performance liquid chromatography fluorescence detection. Acetonitrile was used as collecting solvent for the extraction of PAHs from sediment by vortex-assisted extraction. In DLLME, PAHs were rapidly transferred from acetonitrile to dichloromethane. Under the optimum conditions, the method yields a linear calibration curve in the concentration range from 10 to 2100 ng g-1 for fluorene, anthracene, chrysene, benzo[k]fluoranthene, and benzo[a]pyrene, and 20 to 2100 ng g-1 for other target analytes. Coefficients of determinations ranged from 0.9986 to 0.9994. The limits of detection, based on signal-to-noise ratio of three, ranged from 2.3 to 6.8 ng g-1. Reproducibility and recoveries was assessed by extracting a series of six independent sediment samples, which were spiked with different concentration levels. Finally, the proposed method was successfully applied in analyses of real nature sediment samples. The proposed method extended and improved the application of DLLME to solid samples, which greatly shorten the extraction time and simplified the extraction process. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li Z.-A.,Sichuan University | Tan Q.,Chengdu Environmental Monitoring Center | Hou X.,Sichuan University | Hou X.,University of Sichuan | And 2 more authors.
Analytical Chemistry | Year: 2014

A simple and sensitive approach is proposed and evaluated for determination of ultratrace Zn and Cd in limited amounts of samples or tens of cells based on a novel single drop (5-20 μL) solution electrode glow discharge assisted-chemical vapor generation technique. Volatile species of Zn and Cd were immediately generated and separated from the liquid phase for transporting to atomic fluorescence or atomic mass spectrometric detectors for their determination only using hydrogen when the glow discharge was ignited between the surface of a liquid drop and the tip of a tungsten electrode. Limits of detection are better than 0.01 μg L-1 (0.2 pg) for Cd and 0.1 μg L-1 (2 pg) for Zn, respectively, and comparable or better than the previously reported results due to only a 20 μL sampling volume required, which makes the proposed technique convenient for the determination of Zn and Cd in limited amounts of samples or even only tens of cells. The proposed method not only retains the advantages of conventional chemical vapor generation but also provides several unique advantages, including better sensitivity, lower sample and power consumption, higher chemical vapor generation efficiencies and simpler setup, as well as greener analytical chemistry. The utility of this technique was demonstrated by the determination of ultratrace Cd and Zn in several single human hair samples, Certified Reference Materials GBW07601a (human hair powder) and paramecium cells. (Graph Presented). © 2014 American Chemical Society.

Li M.,China National Environmental Monitoring Center | Jia L.,Beijing Municipal Research Institute of Environmental Protection | Zhang F.,China National Environmental Monitoring Center | Hu M.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | And 2 more authors.
Atmospheric Pollution Research | Year: 2016

Statistical analyses were carried out on the characteristics of haze weather and their relation with air quality and meteorological factors using data recorded by the national air quality and meteorological monitoring network of Chongqing, China in 2013. The results showed that the hourly occurrence rate of haze in Chongqing was 81.3% and that 67.2% of the total number of haze hours was at the level of mild to light haze. Haze was more likely to occur in autumn and winter (67.2% of the total number of hours; occurrence rate 97.5%) and was more likely to occur between 22:00 and 10:00. Haze mainly occurred when the wind speed was <1.2 m s−1 and the relative humidity was >50%. Haze rarely occurred when the wind speed was >3.0 m s−1 and the relative humidity was <30%. There was a positive correlation between temperature and visibility. The occurrence rate was higher with positive variations in the 24-h temperature records. The main factor affecting haze was the level of PM2.5 pollution. Haze mainly occurred when ρ(PM2.5) was between 35 and 250 μg m−3, accounting for 86.4% of the total number of hours of haze. When ρ(PM2.5) was >75 μg m−3, the occurrence rate of haze was 100.0%. The mean value of ρ(PM2.5)/ρ(PM10) during the hours of haze was 72.9%, 17.7% higher than that at other times. The number of hours with air pollution accounted for 48.8% of the total number of hours, far less than the occurrence of haze. When the ambient air quality was excellent or good, haze was present in 65.4% of hours. We suggest that there are differences between the assessment of air quality and the definition of haze used in China. The relationship between haze and air quality would be better matched if we used the World Meteorological Organization's definition of haze (visibility < 5.0 km). © 2016 Turkish National Committee for Air Pollution Research and Control

Leng G.,University of Sichuan | Yin H.,Chengdu Environmental Monitoring Center | Li S.,University of Sichuan | Chen Y.,Chengdu Environmental Monitoring Center | Dan D.,University of Sichuan
Talanta | Year: 2012

A simple and fast solvent microextraction method termed vortex-assisted liquid-liquid microextraction (VALLME) coupled with high-performance liquid chromatography-vapor generation atomic fluorescence spectrometry (HPLC-CVAFS) has been developed for the trace analysis of methylmercury (MeHg), ethylmercury (EtHg) and inorganic mercury (Hg2) in sediment samples. Carbon tetrachloride was used as collecting solvent for the extraction of mercury species from sediment by a vortex-assisted extraction. In VALLME, 100 μL 1% (m/v) l-Cysteine were used as extraction solvent and were injected into 4 mL carbon tetrachloride. The extraction solvent dispersed into carbon tetrachloride under vigorously shaking by a vortex agitator. The fine droplets could extract mercury species within few minutes because of the shorter diffusion distance and larger specific surface area. After centrifugation, the floating extractant phase restored its initial single microdrop shape and was used for HPLC-CVAFS analysis. The parameters affecting the extraction efficiency of the proposed VALLME such as extraction solvent, vortex time, volumes of extraction solvent and salt addition etc. were investigated. Under the optimum conditions, linearity was found in the concentration range from 0.1 to 25 ng g-1 for MeHg, 0.2 to 65 ng g-1 for EtHg, and 0.1 to 30 ng g-1 for Hg2. Coefficients of determination (R2) ranged from 0.9938 to 0.9972. The limits of detection (LODs, signal-to-noise ratio (S/N)=3) were 0.028 ng g-1 for MeHg, 0.057 ng g-1 for EtHg, and 0.029 ng g-1 for Hg2. Reproducibility and recoveries were assessed by testing a series of 6 sediment samples, which were spiked with different concentration levels. Finally, the proposed method was successfully applied in analyses of real nature sediment samples. In this work, VALLME was applied to the extraction of mercury species in sediment samples for the first time. Using l-Cys as extraction solvent, the extraction process is sensitive and environmentally friendly and could be achieved within 3 min. © 2012 Elsevier B.V.

Hou X.,University of Sichuan | Hou X.,Chengdu Environmental Monitoring Center | Ai X.,University of Sichuan | Jiang X.,University of Sichuan | And 3 more authors.
Analyst | Year: 2012

A new, miniaturized and low power consumption photochemical vapor generation (PVG) technique utilizing an ultraviolet light-emitting diode (UV-LED) lamp is described, and further validated via the determination of trace mercury. In the presence of formic acid, the mercury cold vapor is favourably generated from Hg 2+ solutions by UV-LED irradiation, and then rapidly transported to an atomic fluorescence spectrometer for detection. Optimum conditions for PVG and interferences from concomitant elements were investigated in detail. Under optimum conditions, a limit of detection (LOD) of 0.01 μg L -1 was obtained, and the precision was better than 3.2% (n = 11, RSD) at 1 μg L -1 Hg 2+. No obvious interferences from any common ions were evident. The methodology was successfully applied to the determination of mercury in National Research Council Canada DORM-3 fish muscle tissue and several water samples. © 2012 The Royal Society of Chemistry.

Yin H.,University of Sichuan | Yin H.,Chengdu Environmental Monitoring Center | Tan Q.,Chengdu Environmental Monitoring Center | Chen Y.,Chengdu Environmental Monitoring Center | And 3 more authors.
Microchemical Journal | Year: 2011

Burken's "donut ring" model was solved correctly, which was developed based upon the anatomy structure and the flow patterns of the tree. The correction of the model solution was validated by our field experimental data statistically. The vertical PAHs in sapwood is described as a carbon-nitrogen-water interaction process, which is companied with the allocation of photosynthate and other non-structure carbon. It could be found that the vertical translocation is related to the height of the sampling position closely. The anisotropy result of the estimated D z and D r is in agreement with the structure of trunk tissue, suggesting that the radial diffusion is much difficult. Although the estimated D z and D r are confirmed to depend upon Kow (the partition coefficient of PAHs in octanol/water), the different dominant factors are demonstrated in our result. Although the metabolism and degradation in Burken's model were neglected, the evidence of degradation presents in this work. 2-Chloro-Nap might be the degradation product of Nap by adding Cl to Nap rings, for 2-chloro-Nap only contains in trunk samples. This result was validated by the first-order degradation equation. The initial degradation reaction mechanism was also discussed briefly. © 2010 Elsevier B.V.

Yin H.,University of Sichuan | Yin H.,Chengdu Environmental Monitoring Center | Tan Q.,Chengdu Environmental Monitoring Center | Chen Y.,Chengdu Environmental Monitoring Center | And 2 more authors.
Microchemical Journal | Year: 2011

Retrospective monitoring of polycyclic aromatic hydrocarbons (PAHs) pollution levels was demonstrated by analyzing the annual rings of gingko (Gingko biloba L.) sampled from the Chengdu plain of southwest China. The samples of gingko trunk section, leaf, bark and its host soil were analyzed for PAHs by gas chromatography/mass spectrometry (GC/MS) after optimized accelerated solvent extraction (ASE). Compared to ultrasonic or soxhlet, ASE has high extraction efficiency thus meaningful contamination information contained in trunk tissue. The distribution of PAHs in gingko trunk, leaf and its host soil indicates that the main uptake pathway might be gaseous and particles-bound deposition via foliage with the exception of two-ring compounds from root, such as Nap and 2-methyl-Nap. PAHs in gingko trunk could be used to reveal the regional and historical contamination information, which is consistent with the environmental history of events (straw incineration) in Chengdu. © 2010 Elsevier B.V.

Zou Y.,University of Sichuan | Zou Y.,Chengdu Environmental Monitoring Center | Yin H.,University of Sichuan | Yin H.,Chengdu Environmental Monitoring Center | And 4 more authors.
Microchemical Journal | Year: 2011

Further interesting information about contamination recorded in gingko annual rings is revealed in this paper. The degradation degrees of varied PAHs in gingko trunk, range 2.4 to 3.4%, are evaluated by using regression analysis and confirmed to depend upon their molecular sizes and chemical properties. For other lipophilic compounds, the translocation and diffusion behaviors conform to our donut model of PAHs in previous work, while for hydrophilic contaminants, the translocation and diffusion are more complicated owing to the second uptake pathways by roots. Further, the gingko tree exhibits selective absorption to heavy metals, such as Cu, Cd, Zn, Cr, Pb, Ni, Fe, and Mn. The relative accumulation degrees of these heavy metals are estimated by comparing to Fe in the soil and the gingko tree, and the result suggests that the gingko accumulates Cr, Cd and Pb from the soil. However, the metals in annual rings might not reflect historical environment changes for their diffusive nature in water-sapwood. © 2011 Elsevier B.V.

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