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Wang B.,University of Sichuan | Wang B.,Mianyang Normal University | Zheng C.-B.,University of Sichuan | Wang J.-W.,Sichuan Environmental Monitoring Center | And 4 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2012

A novel method for the determination of trace amounts of mercury in sediments by sequential injection cold vapor atomic fluorescence spectrometry coupled with microwave assisted digestion was developed in this paper. Satisfactory results were found when the digestion was carried out at 140°C for 5 min by using 10%HCl-50%HNO 3-40%H 2O or 30%HCl-20%HNO 3-50%H 2O media. The linear range was 0.02~30 ng·mL -1 with detection limit of 0.5 ng·g -1. Relative standard deviation for the complete procedure of the analysis of 10 digested sediment samples was 3.7%. Recoveries of the spiked samples were between (91.2±4.3)% and (96.5±4.6)%. The analytical results for three certified reference materials GSD-2, GSD-9 and GSD-10 were consistent with the certified values. The method has been successfully applied to six natural sediment samples. The results indicated that the method was rapid, highly sensitive and precision, and suitable for the determination of trace amounts of mercury in sediment samples. Source

Leng G.,Sichuan University | Feng L.,Sichuan University | Li S.-B.,Sichuan University | Qian S.,Sichuan Environmental Monitoring Center | Dan D.-Z.,Sichuan University
Environmental Forensics | Year: 2013

A simple and rapid method has been developed for the determination of total Hg in drainage sediment. The method is performed by using a sequential injection (SI) system with cold vapor generation atomic fluorescence spectrometry (CVAFS) after a closed microwave assisted digestion. Digestion was carried out at a temperature of 140°C for 5 minutes using a mixture of 10% HCl + 50% HNO3 +40% H2O as digestion acid media. Stability experiment revealed that the extracted samples were stable in 24 hours. The SI-CVAFS system was well optimized. At optimized conditions, the detection limit of the method was 0.5 ng/g-1. Relative standard deviation (RSD) for the complete procedure by the analysis of the 10 digestions was 3.7%. The method was validated against 3 drainage sediment certified reference materials: GSD-2, GSD-9, and GSD-10 and successfully applied to the determination of Hg in the sediment of Pi River, China. © 2013 Copyright Taylor and Francis Group, LLC. Source

Zeng Y.G.,Chengdu University of Technology | Li L.,Chengdu University of Technology | Zhao H.,Sichuan Environmental Monitoring Center
Advanced Materials Research | Year: 2014

The chemical oxygen demand and permanganate index in 2012 in jiuzhaigou water environment were discussed, and their mutual relations were researched. Theoretical references for the establishment of river water pollution prevention mechanisms were provided. The ratio of chemical oxygen demand and permanganate index is 2.71:1 and their linear regression equation is "y = 3.337× 0.7519". © (2014) Trans Tech Publications, Switzerland. Source

Chen Y.,Peking University | Chen Y.,Capital University of Economics and Business | Luo B.,Sichuan Environmental Monitoring Center | Xie S.-D.,Peking University
Atmospheric Environment | Year: 2015

Chengdu is an inland megacity in the Sichuan Basin, where dust influence remained an open question. During a one-year haze campaign, two dust events were identified in March 2013, indicating that desert dust can be transported to Chengdu and impacted local air quality strongly. The suggested low SO2/PM10, NO2/PM10 and PM2.5/PM10 ratios of 0.15, 0.27 and 0.40 could be used as immediate indicators for dust days. On typical dust day of March 12, PM10 was as high as 359.1 μg m-3, and crustal matter contributed 80.5% to total PM2.5 mass (106.6 μg m-3). Enrichment factors of most elements have decreased due to the dilution effect except for Ca and Mg. The dust was mainly from western and northern dust regions in China, including the "Northerly Mongolia Path", "Western Desert Path" and "Northwestern Desert Path". Due to the obstruction of Qinghai-Tibet Plateau on the west, the dust air to Chengdu was mostly from the northeastward direction after passing over Qinling Mountain. Moreover, the air experienced obvious elevation from its source regions driven by the cold front synoptic pattern. The spatial distribution of high AOD (Aerosol Optical Depth) values over 1.2 but low Ångström exponent of 0.5-0.6 around Chengdu verified the coarse pollution patterns. However, the dust pollution was not serious in nearby Chongqing and Guizhou and exhibited weak regional feature, a result different from those in Beijing and Shanghai. © 2015 Elsevier Ltd. Source

Chen Y.,Peking University | Xie S.,Peking University | Luo B.,Sichuan Environmental Monitoring Center | Zhai C.,Chinese Research Academy of Environmental Sciences
Atmospheric Environment | Year: 2014

The Sichuan Basin is a low visibility area in southwest China, where the hilly and basin topography, plus humid and stagnant weather, lead to unique pollution patterns. To identify the characteristics and sources of carbonaceous aerosols, one-year record of 24-h PM2.5 samples were analyzed for organic carbon (OC) and elemental carbon (EC) content following the thermal/optical transmission protocol at three cities (Chengdu (CD), Neijiang (NJ), and Chongqing (CQ)) in the region during May 2012 to April 2013. The annual average concentrations were 19.0±13.3μgOCm-3 and 4.6±2.6μgECm-3 in CD, 18.3±8.4μgOCm-3 and 4.1±1.8μgECm-3 in NJ, and 15.2±8.4μgOCm-3 and 4.0±1.6μgECm-3 in CQ, respectively. Organic matter (1.6OC) plus EC contributed about 40% of PM2.5 mass and displayed weak regional uniformity. Relatively high ratios of OC to EC were observed in the region with 4.3 for CD, 4.6 for NJ, and 3.8 for CQ, respectively. OC and EC pollution in the region exhibited interesting season-dependent characteristics with the lowest concentrations and OC/EC ratios in summer, but higher levels in other seasons. Higher OC/EC ratios in spring and autumn resulted from biomass burning, and in winter were from the enhanced secondary organic aerosol formation under favorable conditions. The exceptionally high OC and EC levels in May and October, mostly notable in CD, resulted from the burning of agricultural residues during harvest period. The high K+ concentrations and the high Kexcess/EC ratios implied the persistent influence of biomass burning throughout the year. Using a novel technique combing the EC tracer method and potassium mass balance in the aerosols, a K/EC ratio of 1.22 was used to retrieve the OC from biomass burning and the estimated contributions were 30.8%, 28.3%, and 21.9% in CD, NJ, and CQ, respectively, while secondary OC contributions to OC were 26.7%, 24.6%, and 25.7% in CD, NJ, and CQ, respectively. © 2014 Elsevier Ltd. Source

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