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Liu S.,National Research Center for Geoanalysis | Liu S.,Key Laboratory of Ecological Geochemistry | Wang H.,China University of Geosciences | Song J.,China University of Geosciences | And 2 more authors.
Communications in Computer and Information Science | Year: 2013

Ion-absorbing Type Rare Earths Ore mining caused a series of environmental problems. The thesis focused on the study of the district for heavy rare earth in Longnan County, Jiangxi Province, South China. It examined characteristics of spatial-temporal variation for vegetation fraction (vf) in study area by 10 images of Landsat TM and ETM+ during 1988 to 2009. The results supported that: (1) there were spatial-temporal differences of vf in each mineral district and the areas for medium to high vf dominated in mineral districts, but low vf distributed on concentrated mining districts; (2) dynamic variation for vf differentiated in each mining area each stage, no change areas dominated in mineral districts, but negative change areas only distributed on concentrated mining districts; (3) the history of production, various technologies and preventive measures were the main factors caused spatial-temporal differences of vf in mineral districts. © Springer-Verlag Berlin Heidelberg 2013. Source

Yang Z.,China University of Geosciences | Yang Z.,Key Laboratory of Ecological Geochemistry | Yu T.,China University of Geosciences | Hou Q.,China University of Geosciences | And 6 more authors.
Journal of Geochemical Exploration | Year: 2014

The evaluation of land quality is fundamental for land use planning. The geochemical evaluation of land quality in China is a basic part of the Multi-purpose Regional Geochemical Survey Project, which classifies land quality based on soil nutrients (e.g., N, P, and K), harmful elements (e.g., As, Cd, Cr, Hg, and Pb), pH, and soil organic carbon content. This project also classifies land quality using indicators, such as air quality, irrigation water quality, and agricultural products safety, and accordingly evaluates land management. This study introduces the scale, unit, indicators, criteria, and grade classification of the evaluation system. Taking the geochemical evaluation of national land quality as an example, we introduce the results for soil nutrient, soil environment, and comprehensive geochemical classifications of land quality in the primary farming areas of China. The results indicate that the proportions of high quality and excellent soil are 47.5% and 38.1% of the total study area, respectively, which are widely distributed in the major grain-producing areas of China. These results can be widely applied for land use planning, improvement of land production potential, and for the prevention and control of endemic diseases. The geochemical evaluation of land quality in China is still in its infancy. Thus, the evaluation methods need further improvement. In addition, some problems arise in the integration of these methods with the existing agricultural land classification and grading systems in China. Many aspects of the current evaluation system, such as methods for obtaining and interpreting results, need to be improved to fully reflect the quality of cultivated land in China and to be in accordance with developed countries worldwide. © 2013 Elsevier B.V. Source

Yu T.,China University of Geosciences | Yang Z.,China University of Geosciences | Yang Z.,Key Laboratory of Ecological Geochemistry | Lv Y.,China University of Geosciences | And 6 more authors.
Journal of Geochemical Exploration | Year: 2014

Mianyang City, located in the Fujiang River Basin, Sichuan Province, is a Se-rich area of China. The distribution of Selenium (Se) in the Mianyang area was studied based on assay data obtained from soil, irrigation water, fertilizer, and rice (grain and stem) samples. The ratio between natural and anthropogenic sources in the area was derived by analyzing the concentrations and spatial distributions of multiple elements (such as Se, cadmium, arsenic, and mercury) in the soil. The controlling factors affecting Se concentration in the soil were also investigated. We established a geochemical model of the Se cycle among the different media (i.e., the atmosphere, water, soils, and plants). We then calculated the annual Se flux caused by various inputs' (such as precipitation, fertilization, and irrigation) and outputs' (such as infiltration, crop harvest, removal of straws from cropland, and volatilization) pathways in the topsoil. We discuss the contribution of different pathways to the Se cycle and provide evidence for exploring Se-rich land in the study area. © 2013 Elsevier B.V. Source

Liu S.W.,Key Laboratory of Ecological Geochemistry | Liu X.D.,Key Laboratory of Ecological Geochemistry | Fan X.L.,China University of Geosciences | Yuan X.,Key Laboratory of Ecological Geochemistry
Advanced Materials Research | Year: 2014

The ion-absorbed rare earth deposit occurred in the South of China is unique all over the world. Since the 1970s, rare earth in Longnan, South China has begun to be mined with leaching methods using oxalates and ammonium sulfate. Although this kind of methods is simple and economic, its presence in the environmental causes a growing environmental problems, especially changes in regional hydrochemical environment. In this paper typical ion-absorbed rare earth deposit-the Longnan rare earth mine, Jiangxi Provence, South China was selected as the study object, where the surface water and groundwater samples were collected. Analytic results show that the mining activities have affected the regional hydrochemical environment, which are expressed in the decreased pH(pH 3-4) the enrichment of REE and heavy metal Pb in water with the maximum of 44760.1 μgL-1and 1550 μgL-1 respectively, and the sulfate(214-1121 mgL-1) ammonium(33.7-268 mgL-1)and nitrate ions(90-468 mgL-1) far beyond the background value. The impaction of the mining area surface hydrochemical environment is severest, then around the mining area, and the main rivers and groundwater in the study area have not been affected yet. © (2014) Trans Tech Publications, Switzerland. Source

Liu S.,Key Laboratory of Ecological Geochemistry | Fan X.,China University of Geosciences | Tian M.,China University of Geosciences
WIT Transactions on Ecology and the Environment | Year: 2014

To probe the environment change of the Badain Jaran Desert during the Last Interglacial, the representative Barunbaoritaolegai outcrop in the southeast of the desert is selected as the research object. The geochemical characteristics of sediment and changed trend of climatic proxies CIA, ICV, silicon-aluminium ratios, silicon-aluminium-iron ratios and paleotemperature, support that the chemical weathering of the researched region is weak and sensitive to climate and environmental change. We believe that the study area has undergone roughly moderately dry weather during 106.4-99.6ka BP, cold wet weather during 99.6- 90.6ka BP and moderately dry weather during 90.6-67.2ka BP since the Last Interglacial. © 2013 WIT Press. Source

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