A sonoluminescent method for on-line monitoring of the natural water quality

Ultrasonic impact on natural waters was applied to identify hydrochemical anomalies from the changes in the characteristics of sonoluminescence generated by ultrasonic cavitation in a flowing water sample. Sonoluminescence excitation spectra characteristic for various natural water pollutants were obtained for the first time. The suitability of changes in the sonoluminescence intensity and in the shape of the sonoluminescence excitation spectra as indicators of hydrochemical anomalies was elucidated.     

Environmental State of Water in the Blagopoluchiya Bay of Solovetskii Island According to Hydrochemical and Hydrobiological Parameters

The results of hydrochemical and hydrobiological studies performed in October 2009, July 2010, and July 2016 in the Blagopoluchiya Bay of Solovetsky Island are given. The concentrations of petroleum hydrocarbons, phenols, oxygen, nutrients, and chlorophyll a, BOD₅, and qualitative and quantitative compositions of phytoplankton have been determined. The integrated pollution and eutrophication indices have been calculated, and the up-to-date water quality in the Blagopoluchiya Bay has been assessed; increased level of seawater pollution has been revealed. The obtained results are important from both scientific and practical viewpoints with respect to environmental safety of the community facilities in the study region.

     

Understanding the groundwater dynamics in the Southern Rift Valley Lakes Basin (Ethiopia): multivariate statistical analysis method, oxygen (δ 18O) and deuterium (δ 2H)

Multivariate statistical analysis is very important to classify waters of different hydrochemical groups. Statistical techniques, such as cluster analysis, can provide a powerful tool for analyzing water chemistry data. This method is used to test water quality data and determine if samples can be grouped into distinct populations that may be significant in the geologic context, as well as from a statistical point of view. Multivariate statistical analysis method is applied to the geochemical data in combination with δ ¹⁸O and δ ²H isotopes with the objective to understand the dynamics of groundwater using hierarchical clustering and isotope analyses. The geochemical and isotope data of the central and southern rift valley lakes have been collected and analyzed from different works. Isotope analysis shows that most springs and boreholes are recharged by July and August rainfalls. The different hydrochemical groups that resulted from the multivariate analysis are described and correlated with the geology of the area and whether it has any interaction with a system or not.     

Assessment of the Climate Change Impact on the Quality and Quantity of Drinking Water Sources in Armenia

Nowadays the climate change impact on water resources has become evident worldwide. More vulnerable are freshwater resources, the feeding of which depends on atmospheric precipitation and snowmelt water. Freshwater reduction deteriorates water supply and increases water demand. In the recent decade, a significant reduction of the river run-off against the base period has been recorded in Armenia. The reduced river run-off has affected the hydrochemical balance of water resources.In the present work, we have studied the changes in the river run-off and hydrochemical parameters in the water sources of the Geghi, Meghriget, Marmarik, and Gegharot rivers in Armenia. The resulting data have shown that the climate change reduces the water resources and changes the chemical composition of the river water. The sources of the investigated rivers became enriched with calcium, and the concentrations of iron and manganese in the Gegharot river extremely rise in autumn and exceed the WHO drinking water standards.     

Environmental isotope-based integrated hydrogeological study of some Ethiopian rift lakes

Environmental isotope (²H and ¹⁸O) techniques supported by hydrochemical surveying, water balance and conventional hydrogeological mapping were used to study the hydrogeological system of four major lakes located in a closed central Ethiopian rift basin. The focus of attention is the groundwater and surface water interaction and the subsurface hydraulic connection of the lakes. The result shows that despite their geographic proximity, the lakes have highly variable isotopic and hydrochemical signature owing to geological and geomorphological factors. Two of the lakes are alkaline and found to be terminal from both surface water and groundwater point of view. They are in the state of high evaporation with respect to present day precipitation. The groundwater flow converges from all sides of the basin and plays very important role in the water balance of all the lakes. Major flow system in the rift and the hydraulic connection of the lakes is strongly controlled by the direction and extent of the extensional normal faults.     

Water migration of elements in Ornithogenic ecosystems of the North Pacific islands

Specific features of the chemical composition of surface water and water migration of elements in North Pacific islands with large population of marine colonial birds were analyzed. Ornithogenic factor was found to be determining in the composition of surface water in such ecosystems. The concentrations of nutrients (N, P, S, K) are informative hydrochemical parameters reflecting the effect of birds on the intensity of their migration in water. Spacious areas subjected to biogeochemical impact are formed around the islands populated by seabird colonies.     

Chemometric and trend analysis of water quality of the South Chennai lakes: an integrated environmental study

In order to bring out the nature of the factors influencing lake water composition, multivariate statistical analysis and trend analysis were performed based on the hydrochemical data of the study area, namely, South Chennai. Change in land use pattern and settlements along the banks of the lakes alters the quality and quantity of the surface water. In the present study, the R‐mode factor analysis and cluster analysis were applied to the geochemical parameters of the water to identify the factors affecting the chemical composition of the lake water. Dendograms of both the seasons give three major clusters, reflecting the groups of unpolluted to moderately polluted, polluted, and heavily polluted stations. The movement of stations from one cluster to another clearly brings out the seasonal variation in the chemical composition of the lake water. The complex hydrochemical data of the surface water were interpreted by condensing them into three major factors. Factor score analysis was used successfully to delineate the stations under study and the role of the contributing factors, and the nature of factors responsible for the variation in chemical composition of the water has been clearly brought out. Results of trend analysis using ArcGIS clearly indicate that the trend in water quality is deteriorating at a faster rate in the eastern part of the study area. It is understood that although natural shifts probably can account for some of the variation, it is most likely that human activities play a major role in affecting the water quality on a regional scale. Copyright © 2014 John Wiley & Sons, Ltd.     

Examination of the disinfecting properties of calcium peroxide and its suitability for improving hydrodynamic characteristics of surface water bodies

The fundamental possibility of using solid peroxides of alkaline-earth metals for water disinfection purposes was explored. The maximum peroxide concentration in solution is achieved with addition of a mixture of boric and phosphoric acids. Water treatment with calcium peroxide leads to stable dissolved oxygen levels and improves some hydrochemical characteristics of surface water bodies.     

Spectrophotometric determination of polymeric flocculants in waters of different types

Previously studied reactions of the formation of ion associates between polyallyldimethylammonium chloride (PADAC) and triphenylmethane dyes were used in the determination of the residual concentration of polymeric flocculants. Rapid procedures were developed for analyzing hydrochemical objects of different types without the separation of PADAC and the effect of interferents was taken into account. The analysis of process solutions of water treatment was performed using the reaction with Xylenol Orange; the analysis of potable water and purified sewage waters was based on the reaction with Erythrosine. The precision of the procedures is at a level of RSD ≤ 20%. The systematic error does not exceed the tolerable level if the concentrations of metals and surfactants in the studied water are lower than their maximum permissible concentrations.     

Determination of microgram amounts of arsenic in geological materials and waters by wavelength-dispersive x-ray fluorescence spectrometry

Microgram quantities of arsenic are determined in geological materials or water samples by coprecipitating the analyte with elemental selenium and using x-ray fluorescence directly on the precipitate. The coprecipitation step removes elemental interferences and converts the sample to a thin film. The selenium matrix enhances the fluorescent emission of arsenic which enables 0.2 μg g^?1 to be determined. The method is applied to a series of geological reference materials and a seawater sample.     

Harrington’s desirability function for natural water quality assessment

The theoretical analysis of the possible application of Harrington’s desirability function for the state of natural ecosystems assessment was made. It was shown that the desirability function with double limiting should be used for water quality objects assessment. The function makes it possible to eliminate arbitrary rule while the number of quality classes at different ways of optimization (typification, classification etc.) of information was determined. This resulted in mathematically valid limitation to the maximum 5 types of the first level. It was underlined that if even one particular response or a particular desirability function does not satisfy the requirements, the general estimation should be considered unsatisfactory, in spite of the fact that the other parameters (properties) of the studied system were satisfied. The tables were made which gave the possibility to assess the up-to-date state of the Rybinsk Reservoir ecosystem according to the content of nutrients and organic matters on the basis of future mesurments. The seasonal pattern of hydrophysical, hydrochemical and hydrobiological processes should be taken into account in order to make more accurate the water quality assessment at the concrete time in the definite site in the Rybinsk Reservoir area.     

An intercomparison exercise for trace metal monitoring in oxygen-rich and anoxic Baltic waters

Seawater samples for a laboratory intercomparison of trace metal concentrations (Mn, Fe, Ni, Cu, Cd, Pb) in the dissolved (<0.4 μm filtered) and particle-bound phases as well as total and reactive Hg were collected in the Gotland Basin, a region in the Baltic Sea with trace metal gradients in the halocline and the redox boundary. Two laboratories took part in this exercise, each laboratory analysing samples from two vertical profiles collected using ”clean” sampling techniques. The hydrographic and hydrochemical situation was determined to characterise the water column and help interpret the results. An estimation of the conformity of the two laboratories was performed by comparing the results with international intercalibration exercises and certified reference materials. For all metals the characteristic vertical distribution and the concentration range of the data were comparable to other results published for the region. The concentration differences in the amount contents of Mn, Fe, Ni, Cu, Cd, Pb and Hg determined between both laboratories were better than the confidence intervals given by an ICES (International Council for the Exploration of the Sea) international comparison exercise for Baltic waters. Differences for Ni in the anoxic water body are attributed to the sulphidic matrix and their influence on the different methods used by the laboratories. For Pb and Hg the concentrations were near the detection limit of our methods, low level contamination was possibly responsible for the concentration differences. Small differences for dissolved Mn were attributed to different sampling techniques. We conclude that sampling and sample handling are still weak links in the trace metal analysis of anoxic seawater and that the analytical methods we used for this exercise are satisfactory for the accurate determination of Cd, Cu, Pb, Mn, Fe, and also for studying biogeochemical cycling of these trace metals in oxygen-rich and anoxic water bodies. Received: 8 February 2001 Accepted: 8 August 2001     

Dehydration of polymeric hydrogels designed for gelcasting method in ceramics

Key issue in the gelcasting method is the way water is released from the ceramic–hydrogel system. It is the first step to the formation of ceramic materials called green body. The purpose of the presented investigations is to establish the range of temperatures in which dehydration of the various hydrogels takes place, and at what temperatures the eight prepared hydrogels are disintegrated. The set of hydrogels polymers was obtained by radical polymerization from ionic and non-ionic monomers. The polymers were solved in water causing formation of clear gels. The dehydration and thermal decomposition of the obtained hydrogel samples was studied using thermal analysis techniques. The amount of water contained in hydrogels was determined as well as the temperature and products of polymer disintegration. Enthalpies of dewatering were also determined.     

Features of the Hydrochemical Regime of Water Bodies of Urbanized Areas in Summer: I. Biogenic and Organic Substances

Russian Journal of General Chemistry - The article summarizes the results of long-term studies of the hydrochemical regime of some lakes of the Kiev city as an example of the urbanized area water...     

Reactivity of Water and Alcohols toward Carbocations Generated in the Photolysis of 2,2,4,6-Tetramethyl-1,2-dihydroquinoline

The rate constants of the decay of carbocation generated in the photolysis of 2,2,4,6-tetramethyl-1,2-dihydroquinoline and the composition of reaction products were studied as a function of solvent composition in the mixtures H₂O–ROH and MeOH–ROH (R = Et, n-Pr, and i-Pr). The rate constants of carbocation decay in alcohols are more than 20 times higher than the corresponding rate constants in water. As follows from the composition of the products obtained in the photolysis in the alcohol–water mixtures, MeOH is only 1.4 times more reactive than water, and EtOH and n-PrOH are even less active than water. The inconsistency in the product composition in the mixtures and the values of the observed rate constants in these solvents was explained by the two-step mechanism of the reaction: the reversible formation of an adduct of the carbocation with the solvent components and subsequent proton transfer to the solvent to form the final product, with the first step determining the product composition and the second step determining the rate of carbocation decay. The relative rate constants of alcohols and water were determined for the two steps. The preferred solvation of the carbocation with water also contributes significantly to the reaction kinetics and the product composition in the water–alcohol solutions.     

Implementation of solid-phase microextraction with micellar desorption method for priority phenolic compound determination in natural waters

Eleven phenolic compounds considered by the Environmental Protection Agency to be priority pollutants are extracted and determined in different water samples. The method involves the extraction and clean-up step of target compounds by solid-phase microextraction and micellar desorption (SPME-MD) and a second step of determination by liquid chromatography with diode array detection. Different fibers and surfactants are evaluated for the analysis of these target analytes in water samples. In the optimum conditions for the SPME process, recoveries for the target compounds are between 80% and 109%; relative standard deviations are lower than 10%, and detection limits are in the range 0.3-3.5 ng/mL. The main advantages of this method are the combination of time and efficiency, safety, and an environmentally friendly process for sample extraction prior to instrumental determination. This demonstrates that SPME-MD can be used as an alternative to traditional methods for the extraction and determination of priority phenolic compounds in natural waters from different origins.     

The state of water in different forms of sulfo ion-exchange fiber

The state of water in the copper, zinc, and cobalt forms of VION KS-3 ion-exchange fiber is investigated by derivatography. The presence of differently bound water is found. For each step of water removal, hydration numbers of the fiber are determined. It is shown that the amount of water in the fiber depends on its ionic form.     

Hydration mechanism of polysaccharides: A comparative study

Water sorption was studied at 20 °C on films composed of different natural polymers. Three polysaccharides were investigated: chitosan, cellulose, and alginate. The major differences between these polymers, from a structural point of view, lay in the substitution of an OH group by an NH₂ function for chitosan and by an ionic COO^?Na⁺ group for alginate. An analysis of the experimental water sorption isotherms, expressed as the number of water molecules sorbed per repeating unit in the amorphous phase, associated with an analysis of the enthalpy profile related to the water sorption allowed us to propose a water sorption mechanism in two steps for all the polymers: water sorption on polymer‐specific sites in the first step and water clustering around the first sorbed water molecules in the second step. It was determined that two water molecules interacted with the polymer chains for cellulose and chitosan, whereas four water molecules were bonded to alginate chains. The specific sorption sites were identified as OH groups for cellulose, OH and NH₂ groups for chitosan, and ionic and OH groups for alginate. A systematic reduction of the half‐sorption time was observed in the activity range corresponding to this first sorption step, and it was explained by a water plasticization effect. On the other hand, an increase in the half‐sorption time was observed in the second sorption step, at a high activity (>0.8), for chitosan and alginate. A modelization associating the Guggenheim–Anderson–de Boer model and the clustering theory, applied to our systems, allowed us to relate the occurrence of this last phenomenon to the formation of water clusters containing more than two water molecules. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 48–58, 2005     

Synthesis and properties of residual graphite nitrate obtained by treatment of graphite nitrate with water

The possibility of obtaining residual graphite nitrate by water treatment of graphite nitrate and its subsequent drying was studied. The expansion coefficients were determined in the temperature range 500–900°C with a step of 100°C for the samples obtained.     

Getrennte Bestimmung von organischen Halogenoder Schwefelverbindungen in W?ssern nach Adsorption an Aktivkohle und schrittweiser partieller Desorption

Summary A method is described for the separation of mixtures of halogenated hydrocarbons, adsorbed on charcoal, by controlled thermal desorption. In a second step the desorbed species are burned. The generated halogenide ions are determined coulometrically. The method was applied to real water samples. It can also be applied to determine organic thiocompounds. Thiobenzamide and 2-mercapto-ethanol were used as model substances.

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Herrn Prof. Dr. G. Tölg zum 60. Geburtstag gewidmet