共查询到20条相似文献,搜索用时 15 毫秒
1.
Geochemistry and Genesis of Fluoride-Containing Ground Waters in India 总被引:13,自引:0,他引:13
B. K. Handa 《Ground water》1975,13(3):275-281
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Widely applied bioindication methods are analyzed based on the survey data of 1980–1996 for over 400 lakes and 300 watercourses in the northeastern Fennoscandia known to experience anthropogenic impact (toxification, acidification, eutrophication, and thermofication). Representative results of hydrobiological analysis of the quality of surface waters in areas with mixed toxic pollution (or anthropogenic acidification) may be obtained if methods are applied, different from the bioindication methods that are now accepted as standard for Russia, along with methods of biotesting natural waters. The saprotoxibity index, Kola biotic index, acidification estimation scale, biotesting methods were developed and adapted to regional conditions. 相似文献
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Major Ion Characterization of Coastal Saline Ground Waters 总被引:1,自引:0,他引:1
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Results of studying Fe(III) hydrolysis and sorption of heavy metal compounds by organic matter of bottom sediments are discussed. The rate of Fe(III) hydrolysis is found to be largely determined by the concentration of dissolved organic substances. Values of kinetic parameters are obtained for heavy metal compounds sorption under static and dynamic conditions. Calculating the solubility of Fe, Cu, Cd, Zn, and Pb sulfides allowed the assessment of the amount of metals lost by bottom sediments due to the formation of metal complexes with dissolved organic substances contained in natural waters. 相似文献
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Joint Management of Surface and Ground Water Supplies 总被引:10,自引:0,他引:10
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In the Rhode River estuarine/watershed area, increased acidity of precipitation from atmospheric acidic deposition has deleterious effects on the freshwater ecosystems. One of the characteristics of an acidic watershed is the mobilization of aluminum from soils to aquatic environment. Increased concentrations of aluminum in surface waters are toxic to living organisms. Detection of long-term changes of acidity and elevated Al concentrations in surface and soil waters is a central issue. In this present paper, the dynamics ofAl speciation in the shallow ground waters from Rhode River watershed 110 (la) were investigated. This research provides a unique, regional analysis of important controls on the transport of Al speciation through the rural watershed of the Chesapeake Bay. 相似文献
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A Survey of Techniques for Predicting Earthquake Ground Motions for Engineering Purposes 总被引:2,自引:0,他引:2
Over the past four or five decades many advances have been made in earthquake ground-motion prediction and a variety of procedures
have been proposed. Some of these procedures are based on explicit physical models of the earthquake source, travel-path and
recording site while others lack a strong physical basis and seek only to replicate observations. In addition, there are a
number of hybrid methods that seek to combine benefits of different approaches. The various techniques proposed have their
adherents and some of them are extensively used to estimate ground motions for engineering design purposes and in seismic
hazard research. These methods all have their own advantages and limitations that are not often discussed by their proponents.
The purposes of this article are to: summarise existing methods and the most important references, provide a family tree showing
the connections between different methods and, most importantly, to discuss the advantages and disadvantages of each method.
相似文献
John DouglasEmail: |
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A method for determining the critical loads of acid fallout for surface waters is described. Adaptation of the method for estimating the degree of water acidification in the Kola North is demonstrated in the process of large-scale investigations carried out in this region. The limiting value of the acid-neutralizing capacity of waters needed for preventing the aquatic ecosystems from degradation is substantiated. The loads of acid fallout in 17% of 460 examined water systems are found to exceed the critical limits and create the conditions for further development of adverse processes in water systems. 相似文献
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地震反应分析中输入界面选取合理与否对设计地震动参数有重要影响。基于唐山地区钻孔剖面,分别选取剪切波速为500m/s的硬黏土和800m/s的岩石顶面作为基岩输入界面,采用一维等效线性化方法讨论中硬场地输入界面的选取对地表地震动参数的影响,结果表明:(1)地表峰值加速度放大倍数及地表加速度反应谱特征周期都随输入界面深度的增加而递增,且这种递增与输入地震动的强度及频谱特性都有密切联系;(2)随着输入界面深度的增加,地表加速度反应谱几乎全频段内增大,仅在短周期内出现减小的情况,但幅度十分有限;(3)中硬场地地震反应分析中基岩输入界面宜取剪切波速为800m/s的土层顶面。 相似文献
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Ammonium Ion, Humic Materials, and Trihalomethane Potential in Northeastern Kansas Ground Waters 总被引:1,自引:0,他引:1
Glacial buried-valley aquifers serve as primary sources of potable ground water in northeastern Kansas. A long known problem, however, is that a large percentage of well waters in this region exceed the U.S. Environmental Protection Agency (EPA) limits for nitrate (NO−3). A detailed study of the hydrogeology and water quality of the buried valleys has confirmed the nitrate problem and led to a recognition that some well waters with low ( 5 mg/l) NO−3 concentrations have anomalous ( 0.5 mg/l) ammonium ion (NH+4) levels, with an NH+4 range from <0.1 to 4.8 mg/l. The extractable NH+4 concentrations in related glacial sediments range up to approximately 75 mg/kg, and the amounts generally increase from an average of 2 mg/kg in the topsoil downward to bedrock. Migration of brines from subjacent Permian or Pennsylvanian bedrock into the unconsolidated sediments locally may cause desorption of NH+4 and an increase in its levels in the associated ground waters. Numerous test holes drilled in the study area showed a black scum on the fluid and cuttings, which may be from buried humic materials. Recently measured total organic carbon (TOC) contents of the ground waters confirm a significant level in some areas, with a range from 0.1 to 2.4 mg/l as C. Chlorination of water with dissolved organics may lead to production of halogenated compounds. Two public-water-supply well waters contained total trihalomethane (TTHM) levels close to the maximum contaminant level (MCL) of 100 /μg/l in chlorinated samples quenched after one week. The presence of NH+4 inhibits the formation of THMs, but it also can give rise to odor and taste problems in the finished water. The inhibition of THM formation by NH+4 is achieved by reactions which compete with the organics for combination with chlorine. These reactions make maintaining appropriate chlorine residuals difficult and also may lead to production of undesirable side products. Present efforts to evaluate the regional water-quality problems are focused in Nemaha County, Kansas. 相似文献
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Thorsten Christian Rudolf J. Schneider Harald A. Frber Dirk Skutlarek Michael T. Meyer Heiner E. Goldbach 《洁净——土壤、空气、水》2003,31(1):36-44
In the last years more and more often detections of antimicrobially active compounds (“antibiotics”) in surface waters have been reported. As a possible input pathway in most cases municipal sewage has been discussed. But as an input from the realm of agriculture is conceivable as well, in this study it should be investigated if an input can occur via the pathway application of liquid manure on fields with the subsequent mechanisms surface run‐off/interflow, leaching, and drift. For this purpose a series of surface waters, soils, and liquid manures from North Rhine‐Westphalia (Northwestern Germany) were sampled and analyzed for up to 29 compounds by HPLC‐MS/MS. In each of the surface waters antibiotics could be detected. The highest concentrations were found in samples from spring (300 ng/L of erythromycin). Some of the substances detected (e.g., tylosin), as well as characteristics in the landscape suggest an input from agriculture in some particular cases. In the investigation of different liquid manure samples by a fast immunoassay method sulfadimidine could be detected in the range of 1…2 mg/kg. Soil that had been fertilized with this liquid manure showed a content of sulfadimidine extractable by accelerated solvent extraction (ASE) of 15 μg/kg dry weight even 7 months after the application. This indicates the high stability of some antibiotics in manure and soil. 相似文献
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Concept of Water Resources System Management Based on the Combined Use of Surface and Subsurface Waters 总被引:2,自引:0,他引:2
A conceptual basis is proposed for the solution of management problem of water economy systems based on the combined use of surface and subsurface waters. Specific features of the development of groundwater deposits in the context of this problem are discussed. Management of cooling systems of power plants based on the combined management of surface and subsurface water resources is considered as an example. 相似文献
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E. E. Prepas T. P. Murphy G. Lawrence P. A. Chambers R. D. Robarts W. M. Tonn J. M. Burke S. Reedyk 《湖泊科学》1998,10(S1):25-30
Surface waters in western Canada often experience eutrophication-related problems with water quality, specifically high internal phosphorus loading rates and excessive phytoplankton and macrophyte production, that lead to water column anoxia and restricted fisheries habitat. A group of researchers from across Canada were involved for a seven-year period in cooperative programs for surface water quality management in western Canada, based at the University of Alberta. This paper summarises information on two techniques, hypolimnetic oxygenation and lime (Ca2CO3 and Ca(OH)2) application, used in western Canada (specifically, the province of Alberta) to manage eutrophication in standing waters (lakes and reservoirs). 相似文献