Pollution of mercury in soil and some plants of Guiyang City, China     

《中国地球化学学报》2006,25(B08):240-241

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Environmental behaviors of mercury and lead in the soil of polymetallic deposit areas in western Hunan Province     

Yonghua LI Linsheng YANG Wuyi WANG 《中国地球化学学报》2006,25(B08):244-244

Western Hunan Province is one of the most typical assembling areas of cryogenic metallic deposit in China, as well as a main ore-forming zone for some heavy metals. In the region, Hg and Pb pollution was caused by abnormally high concentrations of Hg, Pb in the natural environment and Hg, Pb exploiting/smelting and other human activities, which make the damage to human health more complicated. Generally, heavy metal pollutants in soil are often long-lasting and consequent, with their emission and/or transport into the environment, resulting in growing hazards to human health posed by elevated heavy metal concentrations in air, water, and food. Therefore, monitoring and understanding their behaviors in soil environment is the most important and urgent task. In this paper, the environmental behaviors and pollution characteristics of soil polluted by Hg and Pb in typical Hg and Pb mining areas in western Hunan were studied. Main results are presented as follows： （1） Western Hunan Province is a high regional geochemical abnormal region on Hg and Pb. The concentrations of Hg and Pb in soils in mercury mining areas were 1 315 and 3. l times higher than the average background of soils in China, respectively. While those in soils in lead mining areas are 14.1 and 6.1 times higher. By using the index of geoaccumulation （Igeo）, it was found that either mercury mining area or lead mining area in western Hunan Province has been polluted by the two elements, the majority of soils in mercury mining areas are seriously polluted by Hg, moderately or light polluted by Pb, while the majority of soils in lead mining areas are moderately or moderately-highly polluted by Pb and moderately-highly polluted by Hg. （2） By the BCR extraction procedures, both Hg and Pb in soils are dominated by residual form, followed by organic-sulfide form. Fe-Mn oxides and acid-exchangeable form are rather low. The total concentrations and each species of Hg and Pb in soils show positive correlations with the concentrations of sands, and negative ones with the concentrations of clays in soils.  相似文献   

Chasing rainbows： The elusive normal and lognormal distribution in geochemistry     

Robert C. Szava-Kovats 《中国地球化学学报》2006,25(B08):248-249

For decades geochemists have debated the nature of the distribution of geochemical dements. The general observation is that major elements tend to approach normal distribution, whereas trace elements tend towards lognormal distribution. In order to establish geochemical baselines and anomalies, the distr/bution of geochemical （typically univariate） data is often compared to normal or lognormal distribution. Geochemical data--particularly when the data set is large-usually fails to fit either distribution. Departures from these distributions are commonly attributed to outliers or mixtures of different geochemical populations. This approach fails for two reasons. First, formal tests for normality are a function of power and effect size. For large data sets, even small departures from normality can result in statistical significance, but not necessarily in practical significance. Second, and more importantly, distr/bution tests on ＂raw＂ or log-transformed data fail to recognize the nature of compositional data. Such data are by definition constrained to positive values whose components （variables） are closed to sum to 100%. Components are not independent, i.e., any variation in any component must be compensated by changes in other components. Log-ratio transformations, developed by John Aitchison to deal with these constraints, have existed for over 25 years, but geochemists continue largely to ignore or dismiss the problem of closure. Log-ratio techniques rid compositional data of their component dependence and the constraint of closure by allowing data to assume any value in Euclidean space. We examined the issue of geochemical data distribution with a large set of stream sediments. The logratio transformation not only reconciles the apparent differences between major and trace element distributions, but also more readily enables the recognition of potentially contaminating populations. Moreover, observations below detection limits, which usually cause pronounced skew in ＂raw＂ or log-transformed data, are readily accommodated with a substitution method, typically decreasing skewness.  相似文献   

Contamination and distribution of heavy metals in urban soil in Zhangzhou City, Fujian, China     

Zhengyu BAO Shengying QIAO Yueming HOU 《中国地球化学学报》2006,25(B08):4-4

The urban environment quality is of vital importance as the majority of people now live in cities. Due to the continuous urbanization and industrialization with rapidly increasing economy in China, metals are continuously emitted into soils, imposing a great threat on human health. Urban soils might be affected by industrial activities, transport, agricultural practice, and waste disposal. An extensive survey was conducted in the highly urbanized Zhangzhou City （Fujian Province, China） using a systematic sampling strategy. Concentrations of Hg, Cd, Pb, Zn, Cu, As, Cr and Ni were measured on 108 topsoil samples collected from parks （0-15 cm）, residential areas and suburban agricultural soils. Statistic approach （cluster analysis） was adopted for identification of natural and anthropogenic influence on heavy metal contents. The maps of metal concentrations in surface soils were made based on geographical information system （GIS） data. All of these aim at assessing the distribution of these heavy metals in the urban environment.  相似文献   

Trends in atmospheric Cd deposition recorded in a 64-meter long ice-core and a 5-m snow pit record from Devon Island, Nunavut, Canada     

Yaping WANG Chunxue XU Suming WANG Ziyi AN 《中国地球化学学报》2006,25(B08):15-15

Along with the rapid development of science and technology, natural matter and energy are further exploited and used. The pollution imposed on nature has also sharply increased. Only do we know the pollution history, can we make a correct appraisal of local environment, get the hold of the main cause of environmental pollution, and then take the effective measures to control the environment？ The evolution of heavy metal concentrations with time in the soil environment in the southern suburbs of Beijing were studied by using annual growth rings of trees. The absorption of 12 elements by different tree species in the same soil type was studied according to their absorption coefficients. The study indicated the differences in adsorption of elements by different species of trees. The adsorption coefficients of the elements Zn, Cd and P are higher. The correlations of nine elements （Na, K, Cu, Zn, As, Sr, Cd, Ba and Pb） in growth rings of poplar trees and those in soils near their roots show that the element contents in growth rings have a positive correlation with the contents in soils near the roots. Based on the logarithmic linear correlation model, the evolution of the contents of the elements Cu, Zn, As, Cd, Ba and Pb in soils from 1982 to 2004 was deduced. The trees have the characters of confirming year precisely, long life and widespread distribution. They are the ideal objects of study on environmental pollution changes. At present, research in China in this aspect is less, and the field of research is expected to further expand. This method can be used to provide richer and more scientific information on the history of environmental pollution and changes during modem urbanization in the past few decades and predicting the evolutionary trend of pollution change.  相似文献   

Discussion on exploitation of mineral resources and ecological environmental issues in Wenquan, Wushan     

Zhenming WEI Guodong ZHENG Yaling CHOU 《中国地球化学学报》2006,25(B08):44-45

Through elementary geophysical prospecting, chemical exploration and geological exploration, there are above 100000 t Mo reserves in Wenquan Wushan, Northwest China. Presently, the molybdenum mine has gone deploitation and construction. Data from drillings indicated many associated elements such as Cu, Pb, Zn, etc. with Mo. Through complete water quality analysis, we found water here comes up to drinking-water standard. This paper investigated the environmental geochemistry characteristics and evaluated water quality in mine field under existing conditions, which may present reference for forecasting the trends of environmental pollution change, underwater environmental monitoring and protection after exploitation. In exploitation of mineral areas, the surroundings of ore areas and groundwater environmental quality are affected correspondingly. The paper analyzed benefication process and tailing disposal process, and consequently, predicted pollution sources, pollution pathway and post-effect that may come along. Also, the interactions between water and rocks with human activity are discussed.  相似文献   

Mercury in coal from the People＇s Republic of China     

Harvey E. Belkin Susan J. Tewalt Robert B. Finkelman Baoshan ZHENG Daishe WU Shehong LI Jianming ZHU Binbin WANG 《中国地球化学学报》2006,25(B08):52-52

The Peoples＇ Republic of China produces and consumes the largest quantity of coal in the world; about 2.19 billion tons of coal were produced in 2005. It is estimated that coal consumption will reach 7 billion tons by 2020. Although the nationwide percentage of electrical production from coal is falling due to increased coal-fired power generation efficiency and alternative sources, China will bum more coal than any other country for the foreseeable future. China also is estimated to be the largest producer of Hg emissions （Dastoor and Larocque, 2004, Atmos. Envirn. 38：147-161）. A recent comprehensive study of anthropogenic Hg emissions in China （Streets et al., 2005, Atmos. Envirn. 39：7789-7806） produced a figure of 536 tons of Hg for the year 1999 with coal combustion （all types） accounting for 38% of the total. Atmospheric Hg emission is an international problem as the upper atmosphere provides effective global transport of mercury. Although the estimates vary, China produces about three times more Hg/t of coal burnt than the USA because of the lack of modem technology for pollution control and limited use of cleaned coal. Knowledge of the mercury content, mode of occurrence, and regional distribution in Chinese coal is vital in order to assess the global atmospheric contribution from Chinese coal combustion.  相似文献   

Geochemistry of heavy metals in soils of the Bogota River Basin, Colombia     

《中国地球化学学报》2006,25(B08):63-63

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Moessbauer and XRD characterization of contaminated sediments by coal mining drainage in Neath Canal, South Wales, UK     

Guodong ZHENG Akihito Kuno Talib Abdulameer Mahdi David J. Evans Masaaki Miyahara Yoshio Takahashi Motoyuki Matsuo Hiroshi Shimizu 《中国地球化学学报》2006,25(B08):137-138

Sediment cores were collected from the upstream of the Neath Canal in South Wales and characterized for their mineral compositions and iron speciation in order to understand the influence of sedimentary properties on the contaminants of heavy metals. The sediments in the canal have been polluted by ocherous precipitate with heavy metals such as arsenic since a major mine water discharge in spring 1993. The sediment core was obtained just from the discharge point in the canal and distinguished into three layers in the field regarding to their physical properties including visible color, sediment particle composition and dryness. X-ray diffraction （XRD） and M6ssbauer spectroscopy revealed vertical variations of minerals and iron species in depth of the sediment profile. The upper layer, reddish-brown, is wet muddy precipitant and is very fine in particle size, consisting mainly of iron oxide and hydroxide. Arsenic is rich in this layer; probably the sorption on iron oxide surface is the main mechanism. The middle layer, 22.0-27.0 cm, is soft deposit in a yellow color and contains sheet silicate, calcite and goethite. The lower part below 27.0 cm is gray to dark gray in color and contains quartz, pyrite, coal particles that are much more similar to normal aquatic sediment. The upper two layers in brown and yellow colors as newly precipitated mud from AMD contain high concentrations of As, Ni under oxic conditions. The lower part as the old canal sediments under reducing conditions contains high Cu and Zn. Chromium is enriched in the limited part of the low layer, just beneath the boundary between the middle and low parts of the sedimentary column, where the redox conditions shifted from oxic to anoxic. It is clear that the distribution of these heavy metals is closely associated with the redox condition reflected in the iron speciation. Thus different treatments are necessary for each layer of the sediment since different mineral and geochemical properties of the sediment will give different impacts on the heavy metals.  相似文献   

Research on surface water environment planning of urban forest conservation in Jiufeng of Wuhan     

Qi AN Shenggao CHENG Gang ZHU 《中国地球化学学报》2006,25(B08):94-94

Conservation of Urban Forest Site in Jiufeng is constructed as an ecotourism function urban forest conservation combining mountain and vegetation resource around. According to fieldwork, the conservation is located in the outskirts of the city where non-point pollution is dominant. In order to master the source intensity and its distribution, data from Quickbird remote sensing in 2004 and field collection are adopted to establish the environment database including data layers of districts, land use, map, soil map, DEM, water and road systems, soil property and economy. Traditional quantitative analysis of non-point pollution intensity has encountered with the following difficulties： （1） Large area of vegetation landscape reconstruction will create tremendous ecological benefits, but calculation of pollution decrease brought by reconstruction is difficult to achieve. （2） In conservation reconstruction will be implemented in the residential are step by step, i.e., of moving, repairing and centralization, which is a complex project with wide time span, leading to inaccurate prediction. （3） Construction of the conservation will speed up the development of local tourism, thus if a single society index is chosen to predict the pollution intensity, the development trend of the region could not be figured out completely. Consequently acreage of different planning land use is counted and models of urban and rural areas respectively help to compute unit pollution load. In the urban area, the pollution load of the same land use is regarded as the function of population density, clean frequency and precipitation, while in the rural area, SCS model, universal soil loss equation （USLE） and pollution transfer model are applied to compute unit pollution load of TN and TP. The results of total pollution load are TN 179.706 kg/a and TP 33.814 kg/a. For impracticability of routine planning measures, the project applies measures of distribution controlling against water erosion and soil loss and concentrated-dispersive controlling to lighten non-point pollution brought by living sewage.  相似文献