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1.
The decrease in Aral Sea area, which started in the 1960s, caused considerable changes in the hydrological, chemical, and biological structure of sea water. Regular observations of Aral water chemistry ceased in the early 1990s. There were no observations of the concentrations of biogenic element compounds in water (the so-called “first-day analyses”). During expeditions of the Institute of Oceanology, RAS, in September 2012 and October 2013, integrated hydrochemical observations were carried out, including measuring the concentrations of biogenic element compounds, dissolved oxygen, hydrogen sulfide, and carbonate equilibrium components. An objective of this study was to develop methods of hydrochemical studies under high water salinity (mineralization). In addition to the standard hydrochemical complex, water samples were taken to determine total water mineralization and the concentration of dissolved and suspended metal forms. The results of these studies are given.  相似文献   

2.
In search for a suitable and fast analytical method for assessing kinds of activated carbon for water purification there were carried out investigations with hydrogen peroxide. According to their catalytic activity, the various kinds of activated carbon are capable of decomposing hydrogen peroxide to different degrees and at different rates. The released oxygen can be determined volumetrically. The results of investigation obtained on always fresh carbon samples with acid and basic groups were discussed on the basis of the velocity constants of the oxygen development. An assessment of quality would be possible, in principle, but the surface characteristic of the kinds of carbon is considerably superimposed by influences of morphology, so that applying this method is advised against.  相似文献   

3.
Long-term data (1945–1989) collected during regular observations of water temperature on a network of Roshydromet stations in different types of water bodies in Northwestern European Russia are generalized. A number of mathematical expressions, which are relatively simple and acceptable for wide circles of researchers, are proposed for the assessment of the thermal state of water bodies. Empirical dependences of the thickness of epilimnion, the depth to thermocline, the type of thermal stratification, seasonal variations in the temperature of water surface, and individual characteristics of the “biological summer” on various geographic factors are established. Elements of thermal regime are calculated for the database of ecological-geographical typification of Karelian water bodies.  相似文献   

4.
Identification of contaminants, determination of their biological hazard and content in water are important practical tasks while assessing water quality in sources of drinking water supply of large cities. Presented herein is a review regarding pharmaceutical pollution of waters in various countries. Given are original data concerning contamination of water objects—sources of water supply of Moscow with components of pharmaceuticals and metabolites of therapeutic agents. Worked out is a retrieval and calculation technology of assessing hazards of substances. Proposed is the use of “structure-activity” calculation technologies for prediction of side effects of pharmaceuticals and pharmacological activity of other organic xenobiotics not used in medicine. Certain ways of decreasing pharmaceutical pollution are recommended.  相似文献   

5.
The lignite coal researched by this study was subjected to a two‐stage activation process performed in the scope of obtaining active carbon from domestic resources. “Activation” and “carbonization” stages were used in the experiments. The modified lignite was produced by impregnating lignite with KOH and washing the activation product with 15% HCl solution after thermal treatment. Increasing KOH dosage also increased the removal efficiency. The variables investigated in adsorption experiments were contact time, initial concentration, pH, and sorbent dosage. Adsorption kinetics was fitted by using the pseudo‐first‐order equation, pseudo‐second‐order equation, and intra‐particle diffusion. Isotherm modeling was carried out using Langmuir, Freundlich, and Dubinin–Radushkevich equations. Selected target compound in this work is common environmental pollutant in waters. A commonly known effect of chloroform is its carcinogenic effect. Therefore, removal of these compounds from water is considerably important. Chloroform removal of 97% for was achieved by the use of Konya region activated lignite.  相似文献   

6.
This study evaluates the performance of two low cost and high performance adsorption materials, i.e., activated carbon produced from two natural waste products: Bamboo and coconut shell, in the removal of three pesticides from drinking water sources. Due to the fact that bamboo and coconut shell are abundant and inexpensive materials in many parts of the world, they respond to the “low‐cost” aspect. The adsorption capacities of two local adsorbents have been compared with commercial activated carbon to explore their potential to respond to the “high quality” aspect. Two pesticides were selected, namely dieldrin and chlorpyrifos, because they are commonly used in agriculture activities, and may remain in high concentrations in surface water used as drinking water sources. The results indicate that the adsorption of pesticides on activated carbons is influenced by physico‐chemical properties of the activated carbon and the pesticides such as the presence of an aromatic ring, and their molar mass. The activated carbon produced from bamboo can be employed as low‐cost and high performance adsorbent, alternative to commercial activated carbon for the removal of pesticides during drinking water production. The performance of activated carbon from bamboo was better due to its relatively large macroporosity and planar surface. The effect of adsorbent and pesticide characteristics on the performance was derived from batch experiments in which the adsorption behavior was studied on the basis of Freundlich isotherms.  相似文献   

7.
Numerical experiments are used in this study to systematically investigate the effects of convergence rate, crustal rheological strength, and lithospheric thermal structure on the dynamics of continental collision. The study focuses on the types, conditions and processes of unstable continental subduction. Modelling results suggest that the development of unstable continental subduction can be promoted by conditions that tend to decrease rheological strength of the lithosphere, such as low crustal rheological strength, “hot” thermal structure of the lithosphere, or low convergence rate. Unstable subduction mode can be further categorized into three types: (1) multi-stage slab breakoff, (2) continuously “flowing” of fluid-like slab into the upper mantle, and (3) large-scale detachment of the thickened orogenic root. These three types of unstable continental subduction are respectively associated with (1) a low convergence rate, (2) “hot” thermal structure of the lithosphere with a high convergence rate, and (3) moderate-high crustal rheological strength with a low convergence rate. It is also revealed that the evolution of crustal melting is dominated by the deformation pattern of continental collision, which is mainly controlled by crustal rheological strength. The modelling results have important implications for understanding of continental subduction mode selection under specific geodynamic conditions.  相似文献   

8.
The calculation of runoff and infiltration parameters is a fundamental task for water budget estimation and water resources management. The “Kenessey method” allows these values to be calculated and its use is widespread among water scientists and practitioners. Due to language barriers and inefficient translation in past decades, the method has undergone some misinterpretations and is now far from its original usefulness and purpose. The use of the modified method can give unreal results for specific climatic zones. The purpose of this paper is to point out these methodological variations and to return to the original approach, improving it with modern technology.  相似文献   

9.
1937年菏泽7级地震是中国近代地震史上具有特殊历史价值的地震:(1)菏泽地震的原始资料有4类载体:文字记载、震区"地震调查表"、地震波记录以及现场老照片,说明这次地震既有历史地震学属性,也有近代地震学属性,体现了中国历史地震学向近代地震学进展转化的时代特色。(2)由于抗日战争全面爆发等多方面原因,菏泽地震后政府基本没有实施有效的救灾行动,灾区陷于困难境地,只有上海华洋义赈会于震后一个月到灾区进行了有限的救助活动。菏泽地震是战争时期发生的灾难性地震,由此提示,在战时发生地震等严重自然灾害的应对问题应引起事先重视。  相似文献   

10.
The existing approaches to and methods for bioassessment of water quality are critically analyzed. The significance of the methodological approach under the concept of ecosystem “health” as the most integral numerical method for assessing pollution effects. Comparative analysis is given to the significance of criteria based on the state of individuals, populations, and communities. The results of practical testing of the methods developed for biological assessment of water quality for some water bodies are presented. Critical levels are established based on the construction of dose-effect dependences. The basic principles for limiting surface water pollution are formulated.  相似文献   

11.
Long-term observation data were used to carry out comparative analysis of variations in the biogenic matter runoff of the Dnestr River over a period of fifty years. Based on data of weekly monitoring in 2002–2004, annual dynamics of biogenic matter runoff was analyzed for the Dnestr River and for Dnestr Liman. It was found out that, in spite of the “buffer” role of the latter, the contribution of biogenic substances, finding their way in the sea with the Dnestr River water, to the eutrophication of the northwestern Black Sea remains appreciable (about 60 thousand ton year?1). Dissolved organic compounds account for 70% of the present-day biogenic matter runoff of the Dnestr River.  相似文献   

12.
以四川省地理环境条件为研究背景,根据相关单位提供的资料,对四川省滑坡危险性等级进行了区划研究。将地形地貌、地层岩性、断裂构造、河流水系、降雨量、地震烈度等6项作为滑坡的主要影响因素,采用模式识别方法进行滑坡危险性等级区划,对算法中所涉及到的危险系数计算公式、因子权重分析、阈值选取等进行了一系列控制试验,验证了算法的可行性以及降低算法中存在的不确定性。采用“识别率”和“改变率”2个准则来判断“分类结果作为新的训练集”,即RTS试验的收敛性,从而给出识别率高、改变率稳定的分类结果,以及能合理反映识别结果的最佳参数。通过3次逐级识别分类,将四川省滑坡危险度划分为7个等级,区划结果与实际滑坡发生情况吻合。本文方法同样适用于其它地区的滑坡危险性等级区划。  相似文献   

13.
Data on the Ruza and Mozhaisk reservoirs are used to analyze the applicability of different sampling methods and bioindication systems for rapid water quality assessment. The collected data were analyzed with the use of twelve biotic indices and their modifications. The mean water quality estimate in the coastal zones of both reservoirs varied from “moderate” to “good” and corresponded to α-mesosaprobic zone. The best performance in saprobity assessment was demonstrated by Pantle–Buck index modified by M.V. Chertoprud in the coastal zone and Balushkina index in soft soils in the central zones of the reservoirs. It is proposed to extend the number of indicator taxa in Pantle–Buck index modified by M.V. Chertoprud by incorporating taxa typical of soft soils, in particular, Chironomid larvae from Chironomus plumosus group. Recommendations are given for carrying out express-monitoring of the state of reservoirs.  相似文献   

14.
In addition to traditional degassing of the melt in the subsurface magma chambers of the “dormant” El’brus volcano, alsodegassing through pores and microcracks that occur in the top of magma chambers has also been detected. It is proven by studies of compactness, porosity, and permeability of the rocks. The speeds at which gases (H, He, H2S, CO2, F, and Cl) pass through gneiss and volcanic rocks were estimated. Magma chambers on the ground surface are expressed in stable thermal anomalies revealed by night-time thermal sounding from an NOAA satellite. The presence of magma chambers at depths of 2–12 km was proven by magnetotelluric sounding [Sobisevich et al., 2003] and gravity studies. In addition to occasional “columns” of bright-white fluorescence above the thermal anomalies, aerosol “clouds” and hydrogen flows were detected by lidar and hydrogen surveying [Alekseev et al., 2007, 2009]. Observation at the same sites detected steam outbursts occurring periodically, the snow-ice cover thaws and the smell of hydrogen sulfide is felt. Geochemical characteristics of degassing were studied by snow sampling from up to 1 m deep pits. They were taken within contours of the thermal anomalies, above active fault zones, in the sites of bright-white fluorescence “columns,” and on a new fumarole locality. It is shown that the degassing of melt was accompanied by the gas transporting many elements (Li, B, Si, P, S, Ca, Zn, Pb, Mo, Ba, W, Hg, Ag, U, Th, I, Au, and Pt) in a fine-grained state (a few microns or possibly nanometers) with an active participation of F and Cl. Native platinum, chalcopyrite, halite, sylvite, barite, gypsum, zircon, opal, chlorinated organics, etc. were for the first time discovered in the Mt. El’brus area using electron microscope studies of solid residue from dehydrated snow samples. “Hidden” ore mineralization genetically related to degassing of melts enriched in ore elements may be supposedly found in paleo- and present-day areas of volcanic activity.  相似文献   

15.
Bair ES  Metheny MA 《Ground water》2002,40(6):657-668
Remediation of ground water and soil contamination at the Wells G & H Superfund Site, Woburn, Massachusetts, uses technologies that reflect differences in hydrogeologic settings, concentrations of volatile organic compounds (VOCs), and costs of treatment. The poorly permeable glacial materials that overlie fractured bedrock at the W.R. Grace property necessitate use of closely spaced recovery wells. Contaminated ground water is treated with hydrogen peroxide and ultraviolet (UV) oxidation. At UniFirst, a deep well completed in fractured bedrock removes contaminated ground water, which is treated by hydrogen peroxide, UV oxidation, and granular activated carbon (GAC). The remediation system at Wildwood integrates air sparging, soil-vapor extraction, and ground water pumping. Air stripping and GAC are used to treat contaminated water; GAC is used to treat contaminated air. New England Plastics (NEP) uses air sparging and soil-vapor extraction to remove VOCs from the unsaturated zone and shallow ground water. Contaminated air and water are treated using separate GAC systems. After nine years of operation at W.R. Grace and UniFirst, 30 and 786 kg, respectively, of VOCs have been removed. In three years of operation, 866 kg of VOCs have been removed at Wildwood. In 15 months of operation, 36 kg of VOCs were removed at NEP. Characterization work continues at the Olympia Nominee Trust, Whitney Barrel, Murphy Waste Oil, and Aberjona Auto Parts properties. Risk assessments are being finalized that address heavy metals in the floodplain sediments along the Aberjona River that are mobilized from the Industri-Plex Superfund Site located a few miles upstream.  相似文献   

16.
Ozonation is a treatment step which was first applied in the 1960s in pool water treatment for disinfection as well as for oxidation of pool water contaminants. Contact time between ozone and pool water was identified to be of significance with an increased elimination efficiency regarding chloramines, trihalogenmethane formation potential and the permanganate index for longer reaction times. Oxidation via OH radicals might be the dominating pathway. In this study ozonation was compared with the ozone based advanced oxidation processes ozone/UV and ozone/hydrogen peroxide regarding the elimination efficiency of both disinfection by‐products (DBPs) and DBP precursors. It was observed that AOPs in comparison to ozonation showed an increased elimination efficiency regarding total organic carbon (TOC), the organically bound halogens adsorbable on activated carbon (AOX) and AOX formation potential. A contact time of 3 minutes between pool water and oxidant turned out to be practically sufficient. Just for the trihalomethane (THM) formation potential ozonation showed a slight advantage compared to the AOPs because ozonation is a highly selective oxidant and OH radical reactions are known to produce small reactive molecules which are easier transformed to THMs. Combination of membrane filtration and AOPs resulted in an elimination of 10 to 90 % of the DBPs and their precursors. The ozone/hydrogen peroxide process is suggested for pool water treatment because of the higher elimination rates compared to ozonation and of economic reasons compared to the ozone/UV process.  相似文献   

17.
Several field studies in bays and estuaries have revealed pronounced subsurface maxima in the vertical profiles of the current amplitude of the principal tidal harmonic, or of its vertical shear, over the water column. To gain fundamental understanding about these phenomena, a semi-analytical model is designed and analysed, with focus on the sensitivity of the vertical structure of the tidal current amplitude to formulations of the vertical shape of the eddy viscosity. The new analytical solutions for the tidal current amplitude are used to explore their dependence on the degree of surface mixing, the vertical shape of eddy viscosity in the upper part of the water column and the density stratification. Sources of surface mixing are wind and whitecapping. Results show three types of current amplitude profiles of tidal harmonics, characterised by monotonically decreasing shear towards the surface, “surface jumps” (vertical shear of tidal current amplitude has a subsurface maximum) and “subsurface jets” (maximum tidal current amplitude below the surface), respectively. The “surface jumps” and “subsurface jets” both occur for low turbulence near the surface, whilst additionally the surface jumps only occur if the eddy viscosity in the upper part of the water column decreases faster than linearly to the surface. Furthermore, “surface jumps” take place for low density stratification, while and “subsurface jets” occur for high density stratification. The physics causing the presence of surface jumps and subsurface jets is also discussed.  相似文献   

18.
The roles of oxygen and its activated species (superoxide radicals, hydrogen peroxide, hydroxyl radicals), as well as that of sulfur compounds, are considered in relation to biological quality and the self-cleaning capacity of freshwater aquatic systems. The effects on the aquatic redox-processes are discussed in terms of atmospheric fallout of sulfur compounds, bottom sediment composition, and input of wastewaters containing reducing substances. It is shown that the totality of anthropogenic influences, and/or unfavourable natural geochemical conditions, as well as climatic effects in a region can increase the significance of one-electron transfer processes in bio-geochemical cycles of oxygen, sulfur and manganese, compared with the significance of two-electron transfer processes. The resulting, reactive intermediate products of one-electron transfer processes are very important with respect to the composition and properties of aquatic systems. Examples are given of practical applications of wastewater treatment, using hydrogen peroxide and UV-irradiation, and of regulation of consumers’ activities which affect natural waters.  相似文献   

19.
By means of UV spectra of cyclohexane extracts from aquatic sediments it is possible to distinguish: “normal” mineral oil aromatics (e. g. of the middle distillation fraction), used oils, and highboiling raffinates, tar oils, and — as representative of aromatics listed in the German drinking water ordinance — fluoranthene. Starting with less selective extractants and the basic UV spectra, it is shown that spectra of higher orders frequently allow a quantitative determination of fluoranthene. If it is justified to assume a constant conversion factor, the result of the measurement can be used to calculate the contents of the whole group of aromatics listed in the German drinking water ordinance. A comparison with other methods (HPLC etc.) and with results from other laboratories showed good agreement. Finally, the diagnostic capacity (fingerprint) of derived spectra is pointed out.  相似文献   

20.
ABSTRACT

Droughts have long impacted humans with adverse consequences, hindering the achievement of the United Nations Sustainable Development Goals. To reduce vulnerability, multiple ways of adaptation have been developed, most of which, historically, focused on “hard-path” implementation of infrastructure. However, since water consumption plays a major role in the supply–demand balance, “soft-path” solutions focusing on the control of water use have recently intensified. Furthermore, due to the dynamic interaction between humans and water, changes might occur over time, requiring adaptation measures to be continually reshaped. We assess the dynamic nature of human adaptation to droughts in the semi-arid Extended Jaguaribe Basin, Brazil. We explore the shift from hard, supply-oriented measures to soft governance, and its causes: natural and socio-economic processes not anticipated in the original water resources policy. The observed phenomenon and discussion of its causes help to build knowledge on human–water interactions that are applicable more generally.  相似文献   

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