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He Q.,Taiyuan University of Technology | Ren Y.,Hubei Geological Research Laboratory | Mohamed I.,Benha University | Mohamed I.,Huazhong Agricultural University | And 3 more authors.
Soil and Water Research | Year: 2013

Four sequential extraction procedures (Sposito, Tessier, Silveira and Bureau Communautaire de Reference (BCR)) were used to evaluate the distribution of some metals (Fe, Cu, Cd and Zn) in a contaminated soil around a mining area. The results showed that Fe and Zn were mainly recovered in the recalcitrant soil fractions, while Cd was primarily localized in the exchangeable fraction. Soil Cu was highly associated with organic matter fraction. The amorphous Fe fraction in Silveira could be recognized as part of the Fe-Mn oxide fraction in Tessier and BCR procedures, while the crystalline Fe oxide fraction was classified into the residual fraction in Sposito, BCR and Tessier schemes. Although the same reagent was used to extract target fraction, less carbonate-bound Cu, Cu and Zn were extracted in Tessier procedure as compared to Silveira method, while Tessier scheme yielded a higher proportion of Fe, Cu and Zn in the Fe-Mn oxide fraction than BCR method. Due to the lack of uniformity of experimental conditions and the differences in extraction reagents, the extraction efficiency of metal species varied with the sequential extraction schemes. Therefore, care should be taken when comparing the results obtained by different sequential extraction procedures. Source

Cheng Z.,Chinese Academy of Geological Sciences | Xie X.,Chinese Academy of Geological Sciences | Yao W.,Chinese Academy of Geological Sciences | Feng J.,Bureau of Geology and Mineral Exploration and Development of Guizhou Province | And 2 more authors.
Journal of Geochemical Exploration | Year: 2014

The 76-element Geochemical Mapping (76 GEM) Project was undertaken in southwestern China in 2000 and in southeastern China in 2008. In this project, 5244 composite samples of stream sediment at a density of one composite sample for each 1:50,000-scale map sheet were prepared from sample archives of the China Regional Geochemistry-National Reconnaissance (RGNR) Project, which have been available since 1978. The 76 elements were analyzed by using inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). In the present study, a new quality-control method known as the visualized standard map method was applied to the results of the 76 GEM project. Mean value and background value, which indicate the average concentration of the 76 elements in southern China, were derived from statistical data. Moreover, geochemical maps were compiled to demonstrate the distribution of the 76 elements in southern China. © 2013 The Authors. Source

Zhao Z.-F.,Wuhan University | Zhao Z.-F.,Hubei Geological Research Laboratory | Chu Q.,Hubei Geological Research Laboratory | Xiang Z.,Hubei Geological Research Laboratory | And 2 more authors.
Yejin Fenxi/Metallurgical Analysis | Year: 2012

A method for simultaneous determination of tungsten, molybdenum and copper in ores was established by inductively coupled plasma mass spectrometry after sodium peroxide fusion-citric acid complex with tungsten-hydrochloric acid acidification. The conditional experiments of flux dosage, citric acid dosage and hydrochloric acid dosage were carried out to obtain sample treatment method. The instrumental parameters for analysis were optimized. The measuring conditions of instrument were selected. The accuracy and precision of analytical method were verified by certified reference material. The relative errors were smaller than 4%. The relative standard deviations (RSD, n=12) were smaller than 5%. The rapid simultaneous determination of tungsten, molybdenum and copper was realized in the same system. The detection range of method was applicable to the analysis of macro and micro amount of tungsten, molybdenum and copper. Source

Li M.,China Geological Survey | Li M.,Chinese Academy of Geological Sciences | Xi X.,China Geological Survey | Xiao G.,China Geological Survey | And 5 more authors.
Journal of Geochemical Exploration | Year: 2014

Since 1999, a new geochemical mapping project, the National Multi-Purpose Regional Geochemical Survey (NMPRGS), has been carried out in the agriculturally and industrially developed regions of China, covering mainly the plains of the eastern and central parts of the country. The primary purpose of this project is to generate systematic multi-medium geochemical data that can be used by subject-matter experts to support the development of policies for protecting the surface environment, improving the efficiency of agriculture and supporting land use planning. Surface (0-20cm) soils were collected at a density of 1 sample/km2 and deep soils (150-180cm) were taken at a density of 1 sample/4km2. Samples from 4km2 for surface soils, 16km2 for deep soils, were composited for chemical analysis. Additionally, lake sediments and near-shore sediments were collected at a lower density. Each sample was analyzed for total content of 52 components (Ag, As, Au, B, Ba, Be, Bi, Br, Cd, Ce, Cl, Co, Cr, Cu, F, Ga, Ge, Hg, I, La, Li, Mn, Mo, N, Nb, Ni, P, Pb, Rb, S, Sb, Sc, Se, Sn, Sr, Th, Ti, Tl, U, V, W, Y, Zn, Zr, SiO2, Al2O3, TFe2O3, MgO, CaO, Na2O, K2O and total carbon), organic carbon and pH. As of the end of 2012, sampling of 1.7millionkm2 has been completed and samples from 1.5millionkm2 have been analyzed. Preliminary achievements have been made in the studies of geochemical variations, the establishment of the natural background and eco-geochemical assessment. An encouraging progress has been made in the application of geochemical knowledge to protecting the surface environment, improving the efficiency of agriculture and promoting sustainable land use. © 2013. Source

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