Time filter

Source Type

Lu H.,Nanjing University | Zhao C.,Nanjing University | Mason J.,University of Wisconsin - Madison | Yi S.,Nanjing University | And 5 more authors.
Holocene | Year: 2011

Previous palaeoclimatic studies in the northeastern Qinghai-Tibetan Plateau (NETP) during the Holocene, mainly using lake sediments, have deepened our understanding of the climatic system in this remote region. The timing and forcing mechanisms of climatic change in this region are still controversial, however. Aeolian sand and silt deposits, which are widely distributed in the NETP, can be readily dated by optically stimulated luminescence (OSL) techniques and reveal the sensitive response of the landscape to climatic change. In this study, aeolian sand and loess at six sites around Qinghai Lake were studied to reconstruct millennial-scale climatic changes during the Holocene. Multiproxy data along with 24 OSL age determinations show that low effective moisture and aeolian activity occurred at c. 13 ka, 10-9.1 ka, and 8.9-7.8 ka. Periods of greater effective moisture may have occurred at ~11 ka and 9 ka, and there is evidence for a previously undocumented wet climate at 4-3 ka. These results show that millennial-scale Holocene palaeoclimatic changes in the NETP cannot be explained simply as direct responses to changes in monsoon precipitation forced by summer insolation. We suggest that changes in effective moisture were determined by the balance between monsoon-induced rainfall and evaporation loss (mainly controlled by temperature). Thus, climatic change in the NETP may have been influenced by complex interactions between the monsoon circulation and local convection/evaporation effects, in addition to large-scale change in the Asian monsoon and the westerlies. © The Author(s) 2010.

Ma R.,Institute of Hydrogeology and Environmental Geology | Shi J.,Institute of Hydrogeology and Environmental Geology | Liu J.,Institute of Hydrogeology and Environmental Geology | Gui C.,Institute of Hydrogeology and Environmental Geology
Journal of Earth Science | Year: 2014

Understanding the controlling factor of groundwater quality can enhance promoting sustainable development of groundwater resources. To this end, multivariate statistical analysis (MA) and hydrochemical analysis were introduced in this work. The results indicate that the canonical discriminant function with 7 parameters was established using the discriminant analysis (DA) method, which can afford 100% correct assignation according to the 3 different clusters (good water (GW), poor water (PW), and very poor water (VPW)) obtained from cluster analysis (CA). According to factor analysis (FA), 8 factors were extracted from 25 hydrochemical elements and account for 80.897% of the total data variance, suggesting that groundwater with higher concentrations of sodium, calcium, magnesium, chloride, and sulfate in southeastern study area are mainly affected by the natural process; the higher level of arsenic and chromium in groundwater extracted from northwestern part of study area are derived by industrial activities; domestic and agriculture sewage have important contribution to copper, iron, iodine, and phosphate in the northern study area. Therefore, this work can help identify the main controlling factor of groundwater quality in North China plain so as to make better and more informed decisions about how to achieve groundwater resources sustainable development. © China University of Geosciences and Springer-Verlag Berlin Heidelberg 2014.

Zhang Y.,Institute of Hydrogeology and Environmental Geology | Ma R.,Institute of Hydrogeology and Environmental Geology | Li Z.,Institute of Hydrogeology and Environmental Geology
Environmental Monitoring and Assessment | Year: 2014

Groundwater quality significantly affects public health. In order to better understand groundwater suitability, a total of 887 shallow groundwater samples were collected from the Hetao Plain (HP), Inner Mongolia, China; the maximum and minimum health guideline values of each element were established in this work. Subsequently, the desirability functions (DFs) theory was employed to evaluate the human health risk of groundwater. The results indicate that 780 of the samples were unsuitable for drinking purposes due to the iron, total dissolved solids (TDS), arsenic, strontium, fluoride, and manganese concentrations present, all of which exceeded their maximum guideline value (MaGV). Only 107 samples were suitable for drinking use; however, these samples also have adverse effects on human health to some extent, due to the extremely lower concentrations of nutrient elements and existence of non-nutrient elements. Based on the observed results, groundwater that is unsuitable for drinking use must undergo bacteriological treatment prior to consumption. It was necessary for residents in the western, central, and northeastern parts of the study area are required to be supplied with certain nutrient elements, such as iron, iodine, molybdenum, manganese, and lithium. According to the human health risk assessment of groundwater, the general public can safely and reasonably consume the groundwater for drinking, agriculture irrigation, and industrial purposes. © 2014 Springer International Publishing.

Qiang W.,China University of Mining and Technology | Yuanzhang L.,China University of Mining and Technology | Yuanzhang L.,Beijing Institute of Hydrogeology and Engineering Geology | Liu Y.,Institute of Hydrogeology and Environmental Geology
Mine Water and the Environment | Year: 2011

Water inrush through a mine floor is a complicated nonlinear phenomenon, which is controlled by multiple factors. Different coal seams can have different vulnerabilities, even if they are in the same mine and the same district. To assess the differences in vulnerability between multiple coal seams, we used data from three coal seams of the Tashan Coal Mine. Analysing the results indicates that the vulnerable index method, which incorporates GIS, has many potential advantages in evaluating the likelihood of water inrushes compared to the water inrush coefficient method that has traditionally been used in China. © 2010 Springer-Verlag.

Zhang L.,Institute of Hydrogeology and Environmental Geology | Chen Z.,Institute of Hydrogeology and Environmental Geology
Advanced Materials Research | Year: 2011

The relation between isotopic compositions of precipitation and surface air temperature provides an unique tool for paleoclimate studies. Ananysis was conducted of monthly and annual mean δ18O content of precipitation and surface air temperature for spatial and a fixed location by using the the data of China (1985∼2002) in Global Network of Isotopes in Precipitation (GNIP) Database.This study shows that there is a positive correlation between δ18O of precipitation and surface air temperature for those stations whose latitude is higher than 34 °∼ 36 °N. The seasonal δ18O-temperature gradient derived from the monthly data of 12 stations in northern China is about 0.34%°C -1. The δ18O-temperature gradient, however, derived from the longterm annual mean data of 13 stations, is about 0.52%°C -1 which is substantially larger than the seasonal gradient. This longterm annual δ18O-temperature gradient could be used as the isotope thermometer for palaeoclimate reconstruction in mid- and high-latitude regions in China. © (2011) Trans Tech Publications, Switzerland.

Ma R.,Institute of Hydrogeology and Environmental Geology | Shi J.,Institute of Hydrogeology and Environmental Geology | Liu J.,Institute of Hydrogeology and Environmental Geology
Acta Geologica Sinica | Year: 2012

The complexity of alluvial-pluvial fan depositional systems makes the detailed characterization of their heterogeneity difficult, yet such a detailed characterization is commonly needed for construction of reliable groundwater models. Traditional models mainly focus on using a single aquifer property to qualitatively or semi-quantitatively characterize the heterogeneity of aquifer, so that they are unable to quantitatively reflect the synthetic heterogeneity of all aquifer properties. In this paper, we propose the heterogeneity synthetic index (HSI) for quantitative characterization of synthetic heterogeneity of an aquifer. The proposed calculation process involves four steps: (1) estimation of the hydraulic conductivity of a sediment sample using the cloud-Markov model, (2) establishment of the sedimentary microfacies distribution model through the Markov chain, (3) characterization of the distribution model of hydrogeological parameters using the improved sequential simulation method according to the "facies-controlled modeling" technique, and (4) application of the entropy weight method to calculate the weight coefficient of the above aquifer properties. The HSI of an aquifer is calculated by superposition of these models according to the corresponding weight coefficient. This approach was applied to the Luancheng aquifer deposit in the southeast Hutuo River alluvial-pluvial fan in the North China Plain (NCP). The results have demonstrated that aquifer 3 which was formed in the middle Pleistocene has the strongest heterogeneity, with an HSI of 0.25-0.75. Aquifer 4 formed in the early Pleistocene shows an intermediate heterogeneity, with the HSI ranging 0.35-0.75. The weakest heterogeneity was found in aquifers 1 and 2 formed in the Holocene and late Pleistocene, with HSI values of 0.40-0.75 and 0.400.80, respectively. The heterogeneity of all the four aquifers is relatively strong in the radial direction of the Huai River alluvial-pluvial fan due to the abrupt change of microfacies. In contrast, in the radial direction of the Hutuo River alluvial-pluvial fan, the microfacies change mildly, and the continuity of hydrogeological parameters is better, which has resulted in weaker heterogeneity of the four aquifers in this direction. Findings suggest that the sedimentary environment has significant effects on the aquifer heterogeneity. Considering that there are many aquifer properties, HSI can quantitatively characterize the synthetic heterogeneity of the aquifer and describe the influence of each aquifer property on the synthetic heterogeneity of the aquifer according to its weight coefficient. Thus the HSI approach can be successfully used to deal with the spatial heterogeneity of aquifer and provide a foundation for studies on contaminant transport.

Ma F.,Institute of Hydrogeology and Environmental Geology | Ma F.,Wuhan University | Chen G.,Wuhan University | Hu C.,Wuhan University | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011

The intelligent drillhole optical imager is employed to analyze the fracture of drill holes. Based on the model for fracture materials, change of permeability tensors can be got by calculating the fracture. Influential factors and errors are aroused when the permeability tensors are characterized. The influence of statistical parameters on the permeability tensors is analyzed. Some methods for reducing the errors are proposed. The method is used in the project of Huangdao Water-Sealed Underground Oil Tank, and it has special superiority in the analysis of permeability tensors and is practical.

Zhang Y.,Institute of Hydrogeology and Environmental Geology | Sun J.,Institute of Hydrogeology and Environmental Geology | Huang G.,Institute of Hydrogeology and Environmental Geology
Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment | Year: 2012

Arsenic exists widely in nature and displays complicated geochemical properties. In atmosphere, soil and water systems, transfer and accumulation of different forms of arsenic are influenced by many physicochemical factors, and different forms of arsenic affect toxicity levels in the environment. Source of arsenic, current state of arsenic in different environmental media and influence on ecology environment by arsenic contamination were summarized in this paper. It is proposed that the existing states of arsenic should be known before removal of arsenic by various treatment methods in order to decrease the hazards to human health and ecology environment. © 2012 Taylor & Francis Group.

Zuo H.-Y.,Institute of Hydrogeology and Environmental Geology | Zhang L.,Institute of Hydrogeology and Environmental Geology
2010 4th International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2010 | Year: 2010

A novel method extracting with ether, deriving by methanol, deteminating with gas chromatography-mass spectrometry (GC-MS) for analyzing 8 kinds of acid herbicide residues in water has been established. The optimum experimental conditions were as follows: Adding 8 drops of concentrated sulfuric acid; adding 1.0 mL methanol; deriving 60.0 min. Linear of all herbicides is good in the range of 0.05 to 2.5 μg/L, and the detection limit were under or equal to 0.02 μg/L. the results gained from method were accurate and stable, and the recoveries of all herbicides were between 82.07∼116.99%at 0.10, 0.50 , 1.00, 1.50μg/L, and the relative standard deviations were below 7.68%. The method is reliable and stable, and so selective that there is no interference in determination of herbicides residues in water. © 2010 IEEE.

He Y.,Institute of Hydrogeology and Environmental Geology | Wang G.,Institute of Hydrogeology and Environmental Geology | Lin W.,Institute of Hydrogeology and Environmental Geology | Zhang W.,Institute of Hydrogeology and Environmental Geology
Open Fuels and Energy Science Journal | Year: 2015

The geothermal resources in sedimentary basin are affected by many factors because the characteristic of geothermal reservoirs is very complex, so the heat storage capacities are hard to calculate. This paper took Dunhuang Basin as an example to analyze the geological structure, stratigraphic structure and the formation mechanism of geothermal water based on the formation characteristics of the geothermal resources. The analysis results showed the geothermal reservoir parameters, including the area, thickness and temperature of the geothermal reservoir and porosity, etc. Based on geothermal reservoir model, the conclusion was that the geothermal resource of Dunhuang basin was 7.75E+16kJ. The results provided an advice for the exploitation of geothermal resources in sedimentary basins. © He et al.; Licensee Bentham Open.

Loading Institute of Hydrogeology and Environmental Geology collaborators
Loading Institute of Hydrogeology and Environmental Geology collaborators