Xi X.,China Geological Survey |
Yang Z.,China University of Geosciences |
Cui Y.,Heilongjiang Institute of Geological Survey |
Sun S.,Jilin Institute of Geological Survey |
And 2 more authors.
Geoscience Frontiers | Year: 2011
Employing the Unit Soil Carbon Amount (USCA) approach, soil carbon storage was calculated across the Northeast Plain of China based on the Multi-purpose Regional Geochemical Survey conducted in 2004-2006 (MRGS). The results indicated that the soil organic carbon (SOC) storage in topsoil (0-0.2 m), subsoil (0-1 m) and deep soil (0-1.8 m) was 768.1 Mt, 2978.4 Mt and 3729.2 Mt with densities of 3327.8 t/km2, 12,904.7 t/km2 and 16,157.5 t/km 2, respectively. These values were consistent with national averages, whereas the soil carbon densities showed a clear increasing trend from the southern area of the Northeast Plain (Liaoning), to the middle (Jilin) and the northern Plain (Heilongjiang) - particularly in terms of topsoil carbon density, which increased from 2284.2, to 3436.7 and 3861.5 t/km2, respectively. In comparison to carbon data obtained from the Second National Soil Survey in 1984-1986 (SNSS), the topsoil SOC storage values from the MRGS were found to have decreased by 320.59 Mt (29.4%), with an average annual decline of 16.0 Mt (l.73%) over the 20 years. In the southern, middle and northern areas of the plain, soil carbon densities decreased by 1060.6 t/km 2, 1646.4 t/km2 and 1300.2 t/km2, respectively, with an average value of 1389.0 t/km2 for the whole plain. These findings indicate that the decrease in soil carbon density varied according to the different ecosystems and land-use types. Therefore, ratios of soil carbon density were calculated in order to study the carbon dynamic balance between ecosystems, and to further explore distribution characteristics, as well as the sequestration potential of SOC. © 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.
Hao L.,Jilin University |
Tian M.,Jilin University |
Zhao X.,Jilin University |
Zhao Y.,Jilin University |
And 2 more authors.
Geoderma | Year: 2016
Trace elements As, Cd, Cu, Hg, and Pb in soils originate from both natural and anthropogenic sources, and intense anthropogenic activity can lead to excessive trace element levels, which are harmful to the environment. We investigated the trace elements in the topsoil of Changchun, China, using stochastic models and the indicator kriging method. The influence of anthropogenic and natural variables on the distribution of trace elements was evaluated, with the proportions of background and anthropogenic sources identified using stochastic models. High-risk maps were constructed using indicator kriging. The results showed that the anthropogenic variables significantly influenced the spatial variations of trace elements. The relative influence of natural variables differed for the different elements. The median values of background As, Cd, Cu, Hg, and Pb were 10.55 mg kg-1, 0.114 mg kg-1, 21.80 mg kg-1, 0.036 mg kg-1, and 25.88 mg kg-1, respectively; while the threshold values were 12.90 mg kg-1, 0.200 mg kg-1, 29.40 mg kg-1, 0.046 mg kg-1, and 29.49 mg kg-1, respectively. The relative contributions of background values to total values of As, Cd, and Cu were greater than 95%, while those for Pb were 91%. In contrast, Hg showed serious pollution, with less than 75% of the total Hg derived from background sources. The geographically extensive Hg pollution is likely influenced by emissions from coal-fired plants and boilers, while other trace elemental pollutants primarily originate from factory emissions. Furthermore, the atmospheric diffusion of Pb and Hg is significant, resulting in their migration to agricultural areas. © 2016 Elsevier B.V.
Wang D.-Y.,Jilin University |
Li Y.-F.,Jilin University |
Bai R.-J.,Jilin Institute of Geological Survey |
Xu Q.,Jilin University
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2011
Based on systematic field investigations and sample collection and test of soil and apple-pear in Yanbian area, by using methods of statistical comparison and correlation analysis, we studied on the spatial differences of soil total calcium, soil exchangeable calcium and calcium in fruit, calcium's convert-absorption characteristics in soil-fruit system and the effect on fruit quality. The aim of the research is to reveal calcium's migration and transformation law and its ecological effect serving for land use. The results show that total calcium is generally lacked in soil of Yanbian area, and calcium's convert-absorption in soil-fruit system differs a lot in different areas. The results also show that calcium's absorption in a variable range has a significant negative correlation with the content of exchangeable calcium in soil. Our results indicate that the exchangeable calcium of soil has a significantly positive correlation with pH of soil and also correlates with the four indexes representing fruit quality, rich content of calcium is helpful to fruit quality.
Cheng H.,Institute of Geophysical and Geochemical Exploration |
Cheng H.,Chinese Academy of Geological Sciences |
Li M.,China Geological Survey |
Zhao C.,Institute of Geophysical and Geochemical Exploration |
And 22 more authors.
Journal of Geochemical Exploration | Year: 2015
A systematic geochemical lake sediment survey has been carried out in major freshwater lakes in China. Surface lake sediment (0-20cm) at a density of 1sample/4km2 and deep lake sediment (150-180cm) at a density of 1sample/16km2 were collected and analyzed with standard procedures. This overview provides a current ecological risk assessment for toxic metal contamination (As, Cd, Cr, Cu. Hg, Ni, Pb, and Zn) in the surface sediments of major freshwater lakes in China. Lake sediment in China poses a moderate ecological risk on a nationwide basis using a potential ecological risk index (PERI). Mercury ranked as presenting the greatest ecological risk, followed by Cd, As, Pb, Cu, Ni, Cr, and Zn. Liangzi Lake was classified as having high ecological risk; Dalonghu Lake, Dianchi Lake, Dongting Lake, Fuxian Lake, and Qilu Lake as having moderate ecological risk; while the other surveyed lakes were classified as having low ecological risk. Uncertainties of risk assessment are also discussed by considering geochemical background, the eco-toxicity of metals and the sensitivities of local benthic communities. These comprehensive findings have provided valuable information for improvement of lake management and pollution prevention and control in China. © 2015 Elsevier B.V..