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Wu R.,Nanjing Institute of Environmental Sciences | Ge S.,CAS Nanjing Institute of Geography and Limnology | Xu L.,CAS Nanjing Institute of Geography and Limnology | Huaqing Z.,Qinghai Environmental Monitoring Center
Research of Environmental Sciences | Year: 2015

In the field of sanitary landfill technology, it is vital to choose the landfill bio-cover materials. The present study investigated the methane oxidation capacity of bio-cover (aged refuse+cow dung+sawdust) and factors including disposal age of aged refuse, temperature, moisture content and initial CH4 and O2 concentrations. The result showed that the disposal year of aged refuse was greatly important to the efficiency of CH4 oxidation. The rates of CH4 oxidation bio-cover B (10 a) and C (15 a) were much higher than bio-cover A (5 a). The optimum temperature and moisture content of CH4 oxidation capacity was 30℃ and 35%. Based on the Michaelis-Menten model, with the correlation coefficient R2=0.993, the maximum rate of methane oxidation Vmax was 5.21 μmol/(g·h) and the Michaelis-Menten constant Km was 5.48%. The bio-cover material even reduced CH4 in anaerobic condition, though the rate was slower compared to the aerobic condition. Approximately 83% of the CH4 was removed during 20 d incubation. Moreover, the bio-cover material produced N2O (a greenhouse gas) during drying-wetting cycle events. The N2O fluxes in the bio-cover with 70% (WPFS) were 1.96 times more than that of 46% (WPFS). The result suggests that landfill bio-cover materials which are mixed by refuse, cow dung and sawdust could efficiently reduce CH4, and the maximum rate of methane oxidation is one or two orders of magnitude faster than other commonly used materials. Therefore, new landfill bio-cover material can be applied to small and medium-sized landfill to reduce emissions of CH4. ©, 2015, Editorial department of Molecular Catalysis. All right reserved. Source


Zhao X.D.,Gansu Agricultural University | Zhang D.G.,Gansu Agricultural University | Shi L.N.,Qinghai Normal University | Yang Y.S.,Qinghai Environmental Monitoring Center
Advanced Materials Research | Year: 2013

The depth variations of soil physicochemical properties in the degraded native grasslands and the artificially restored grasslands were studied in the Three-river headwater areas of Qinghai-Tibetan plateau, China. The results showed: (1) With the increase of the gradient of restoration years, soil water content, total chemical properties, total potassium, phosphorus, available phosphorus and potassium were increased thereafter in the artificial grasslands. (2) With the increase of grassland degradation gradient, soil water content was gradually reduced, and the total N, K, the organic matter didn't gradually reduced also. (3) Both restoration years and degradation degree didn't influence the nutrient distribution in soil. (4) The organic matter, total N and K of degraded grassland were increased by artificial grassland construction. Therefore, artificial grassland construction canbe used as an effective measure of ecological projects in the Three-river headwater area. © (2013) Trans Tech Publications, Switzerland. Source


Lina S.,CAS Northwest Institute of Plateau Biology | Lina S.,University of Chinese Academy of Sciences | Fei R.,CAS Northwest Institute of Plateau Biology | Fei R.,University of Chinese Academy of Sciences | And 3 more authors.
JAOCS, Journal of the American Oil Chemists' Society | Year: 2010

The seed oil of Microula sikkimensis had been intensively studied due to its pharmacological actions. In the present study, seed oil of Microula sikkimensis was extracted using supercritical fluid extraction (SFE). Determinations of the extracts composition were performed by gas chromatography (GC). An orthogonal array design (OAD), OA9 (34, was employed for optimization of the supercritical fluid extraction of the compound with regard to the various parameters. Four factors, namely pressure (21.0-27.0 MPa), the dynamic extraction time, temperature, and Co2 flow rate of the supercritical fluid, were studied and optimized by a three-level OAD. The effects of the parameters on the yieId of seed oil were studied using analysis of variance (ANOVA). The results revealed that the pressure had a significant effect on the yield of seed oil (p < 0.05), while the other three factors, i.e., Co2 flow rate, dynamic extraction time and temperature, were not identified as significant factors under the selected conditions based on ANOVA. The results show that the best values for the extraction condition of seed oil was pressure 24.0 MPa, extraction time 3 h, temperature 45 °C and a Co2 flow rate 20 L/h in the 20-L vessel. © AOCS 2010. Source


Shi L.N.,Qinghai Normal University | Xu X.,Qinghai Environmental Monitoring Center | Zhao X.D.,Qinghai Environmental Monitoring Center | Dou X.Y.,Qinghai Environmental Monitoring Center | Zhao Q.Q.,Haixi Mongolian
Advanced Materials Research | Year: 2014

The human risks of As and heavy metals (Cu, Ni, Cr, Pb, Cd and Hg) in fine particulate matter (PM2.5) in Xining, China is investigated here in this study. Cu, As and Pb are the most abundant elements in stationary monitoring station for atmospheric pollution and mountain Najia. As, Pb and Cr are the most abundant elements in the park of organisms and Xining Special Steel between the studied metals and metalloids in PM2.5. Pb and As showed a higher bio-accessibility. It has been shown that the carcinogenic risks of As, Cd, Cr and Ni in PM2.5 via dermal contact and inhalation exposure are within the acceptable level(<1×10-4) for both children and adults, but there is a potential carcinogenic risk posed by Pb via ingestion. As for non-carcinogenic health risks, the hazard index values for all the studied elements suggested no health risks via ingestion and dermal contact, but a potential one via inhalation of adults. Values of hazard quotient and hazard index indicated the non-carcinogenic risks from the studied metals and metalloids to children via ingestion, dermal contact and inhalation pathways during heating period in Xining given the present air quality. © (2014) Trans Tech Publications, Switzerland. Source


Shi L.N.,Qinghai Normal University | Xu X.,Qinghai Environmental Monitoring Center | Dou X.Y.,Qinghai Environmental Monitoring Center | Zhao X.D.,Qinghai Environmental Monitoring Center
Advanced Materials Research | Year: 2014

PM2.5 is one of the most important components in air pollution. It is also the focus of the most closely watched at home and abroad. Based on its small size, complex components, and strongenvironmental activity, it can be used as a carrier for chemicals, heavy metals, bacteria, toxins and carcinogens into the body. Then, as a result, it will affect Human Body Health. Heavy metals are important components of PM2.5, and the long-term accumulation of heavy metals in PM2.5 poses a great threat on human health and the environment. This paper reviewed the sources, distribution methods,chemical form, detection methods, disposal way, research progress of heavy metals in PM2.5. As a result, it provided a reference for in-depth study on the future. © (2014) Trans Tech Publications, Switzerland. Source

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