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841.
Air Pollution Studies in Central Russia (Tver and Yaroslavl Regions) Using the Moss Biomonitoring Technique and Neutron Activation Analysis 总被引:1,自引:0,他引:1
E. V. Ermakova M. V. Frontasyeva S. S. Pavlov E. A. Povtoreiko E. Steinnes Ye N. Cheremisina 《Journal of Atmospheric Chemistry》2004,49(1-3):549-561
Data of 34 elements, including heavy metals, halogens, rare earth elements, U, and Th in 139 moss samples, collected in Central Russia in 2000–2002 in the Tver and Yaroslavl regions and in the northern part of the Moscow region, are presented. Factor analysis with VARIMAX rotation was applied to identify possible sources of the elements determined in the mosses. The seven resulting factors represent crust, vegetation and anthropogenic components. Some of the factors were interpreted as being associated with ferrous smelters (Fe, Zn, Sb, Ta); combination of non-ferrous smelters and other industries (Mn, Co, Mo, Cr, Ni, W); an oil-refining plant, and oil combustion at the thermal power plant (V, Ni). The geographical distribution patterns of the factor scores are also presented. Dependency equations of elemental content in mosses versus distance from the source were derived. 相似文献
842.
天津市东丽区第四系Ⅱ组深层淡水在长期较强开采状态下未发生水位持续下降及大面积深层淡水成化污染,十余年来地层沉降基本消失.该地多年来中更新统淡水及上更新统、全新统咸水水位具有同步不等幅的动态,证明它们之间联系密切,地层中渗透系数小于10-3m/d的历次海侵沉积层及压实的粘土层具有半透膜特性,咸水越流补给第Ⅱ承压含水组的是淡水.适量加大Ⅱ组淡水开采强度,使其产生越流系统,稳定后不会再加大地面沉降.最终使全新统地下水下入渗水位降低,夺取潜水蒸发的水量.在有咸水分布区,地表入渗水是尚没有引起足够重视的可持续利用地下淡水的补给来源. 相似文献
843.
Operator splitting techniques are widely used in atmospheric modeling in order to reduce the cost of time integration and allow more flexibility by treating each operator separately. However, this is not error free and the magnitude of the error depends on whether the splitted operators commute or not and the magnitude of the splitting time step. In multiphase models, the gas and the aqueous phase chemistries are related through the gas-droplet mass transfer processes. In the present paper, we show that splitting the gas chemistry operator from the aqueous chemistry and mass transfer operator is not appropriate and leads to errors beyond the tolerated thresholds. Analytical expressions for the splitting errors are derived and numerical experiments are conducted. The LAMP chemical mechanism is employed. Time integration is performed with LSODE. 相似文献
844.
地浸采铀矿山地下水污染碱性中和清洗法治理研究 总被引:1,自引:0,他引:1
地浸采矿方法可引起地下水环境的严重污染,文章对地下水污染过程及治理机理进行了阐明,针对地浸铀矿山的污染特点,提出了碱性中和清洗治理方法的设想,并对碱性中和清洗法治理地浸铀矿山的地下水环境污染的方法及治理效果进行了实验研究,采用水文地球化学模式PHREEQC1.6来模拟计算中和清洗液的最佳pH值,提出了对现场清洗治理具有重要意义的一个重要指标——清洗比,实验结果表明,碱性中和清洗法对治理地浸矿山的地下水污染治理效果明显.为我国地浸矿山地下水污染治理工作的开展进行了探索性研究。 相似文献
845.
Water quality in rural areas of the Czech Republic: Key study Slapanka River catchment 总被引:1,自引:0,他引:1
The article evaluates the water quality in rural areas in the Czech part of Labe River catchment using the example of Slapanka River catchment. This river drains a typical landscape of Ceskomoravska Highland. Water quality in rural areas is still very low and the attention is paid to organic substances and nutrients. Increased amount of them in streams is caused mainly by agriculture and production of municipal wastewater resulting in increased eutrophication. A significant part of the article consists in the evaluation of point and non-point sources of water pollution. Identifying the type of the pollution source is helped by regression analysis using data from the public monitoring network. Eleven sampling sites were selected for evaluating the water quality. Physical and chemical analyses were made 12 times during the field monitoring in the years 2001–2003.In long-term development water quality has improved in all monitored parameters during the last 15 years. Least significant improvement has been found with the concentration of nitrate nitrogen. The water quality within the whole catchment area still remains low.To reduce the influence of pollution sources, we recommend the sanitation of diffuse sources of pollution from small settlements with less than 2000 inhabitants, and a successive change from agricultural management and intensive mass production to extensive ways, especially in mountain and sub-mountain areas. 相似文献
846.
847.
LI Chengcai MAO Jietai Alexis K. H. Lau YUAN Zibing WANG Meihua LIU Xiaoyang 《中国科学D辑(英文版)》2005,48(Z2)
The direct correlation between NASA MODIS aerosol optical depth (AOD) products and the air pollution index (API) in Beijing was found relatively low based on the long-term comparison analysis. The correlation improved to some extent after taking account of the seasonal variation of scale height and the vertical distribution of aerosols. The correlation coefficient further improved significantly after considering the influencing factor of Relative Humidity (RH). This study concluded that satellite remote-sensing could serve as an efficient tool for monitoring the spatial distribution of particulate pollutants on the ground-level, as long as corrections have been made in the two aforementioned processes. Taking advantage of the MODIS information, we analyzed a pollution episode occurring in October 2004 in Beijing. It indicated that satellite remote-sensing could describe the formation process of the ground-level pollution episode in detail, and showed that regional transport and the topography were crucial factors to air quality in Beijing. The annual averaged distribution in the urban area of Beijing and its surroundings could be also obtained from the high-resolution retrieval results, implicating that high-resolution satellite remote-sensing might be potential in monitoring the source distribution of particulate pollutants. 相似文献
848.
P. Kumar 《Journal of Earth System Science》2005,114(5):565-571
Based on the inherent property of symmetry of air pollution models, a Symmetrical Air Pollution Model Index (SAPMI) has been
developed to calibrate the accuracy of predictions made by such models, where the initial quantity of release at the source
is not known. For exact prediction the value of SAPMI should be equal to 1. If the predicted values are overestimating then
SAPMI is <1 and if it is underestimating then SAPMI is >1. Specific design for the layout of receptors has been suggested
as a requirement for the calibration experiments. SAPMI is applicable for all variations of symmetrical air pollution dispersion
models. 相似文献
849.
The study of hydrogeochemical data sets frequently calls for statistical dimension reducing techniques. It is well known that
hydrochemical parameters are compositions and, for this type of data, the direct application of classical statistical methods
based on the correlation matrix yield spurious results. But new results on compositional data analysis have identified the
sampling space, the simplex, with an Euclidean space, a fact that allows us to define a simplicial factor analysis strategy,
thus overcoming the problem. For illustration, we use samples from the Llobregat River and its tributaries (NE Spain). Three
unobservable or latent factorial components are extracted, which are identified with pristine waters, potash-mining influence
and urban sewage influence. These three factorial components or compositional factors are plotted in a factorial ternary diagram,
which reflects the relative influence of each one of these factors on each observation. 相似文献
850.
The development and propagation of a pollution gradient in the marine boundary layer over the Arabian Sea during the Intensive
Field Phase of the Indian Ocean Experiment (1999) is investigated. A hypothesis for the generation of the pollution gradient
is presented. Infrared satellite images show the formation of the pollution gradient as the leading edge of a polluted air
mass in the marine boundary layer and also its propagation over the Arabian Sea and the northern Indian Ocean. Aerosol data
measured from two research vessels over the Arabian Sea show a variation in the concentrations caused by the passage of this
pollution gradient. Depth of the pollution gradient was found to be about 800 m. A numerical model was used to simulate the
development of this gradient and its propagation over the ocean. Results show that its formation and structure are significantly
influenced by the diurnal cycle of coastal sea-land breeze circulations along India’s west coast. Transport of aerosols and
gases over the Arabian Sea in the lower troposphere from land sources appears to be through this mechanism with the other
being the elevated land plume. 相似文献