scholarly journals Nature of chemical composition diversity of the East Ttransbaikalia salt lakes (Russia)

2019 ◽  
Vol 98 ◽  
pp. 01003 ◽  
Author(s):  
Svetlana Borzenko
Keyword(s):  
Chemical Composition ◽  
Catchment Area ◽  
Soda Lakes ◽  
Salt Lakes ◽  
Great Role ◽  
Migration Ability ◽  
Geochemical Environment ◽  
Geochemical Conditions ◽  
Ph Values ◽  
Extensive Field

We have developed a new concept for the formation of geochemical types of salt lakes which explains the nature of their different chemical composition under close landscape-climatic and geological-geochemical conditions. The extensive field hydrogeochemical material and thermodynamic calculations demonstrate that in addition to evaporation, the interaction with rocks plays a great role in the formation of the composition of lakes. This interaction begins in the catchment area of a particular lake and continues directly in the lake. Such processes are most widespread in soda lakes, which is confirmed by the presence of the highest pH values (9.0-10.7). Besides, one of the most important processes is sulfate reduction, which results in hydrogen sulphide in lakes fundamentally changes the geochemical environment from oxidizing to reducing one and leads to a change in the oxidation state of many elements, changing their migration ability and, therefore, the ability for concentration or binding by secondary minerals. The presence of an oxidizing environment and sulphides in rocks gives additional sources for sulfates, which ensures the formation of sulfate-type lakes.

ECOLOGICAL AND PHYSIOLOGICAL ASSESSMENT OF CHEMICAL COMPOSITION OF DRINKING TAP WATER IN KHANTY-MANSIYSK AND SALEKHARD

2020 ◽  
pp. 159-167
Author(s):  
V.V. Lapenko ◽  
L.N. Bikbulatova ◽  
E.M. Ternikova
Keyword(s):  
Drinking Water ◽  
Chemical Composition ◽  
Water Samples ◽  
Tap Water ◽  
Iron Concentration ◽  
Absorption Spectrometry ◽  
Northern Region ◽  
Transport Processes ◽  
Magnesium Concentration ◽  
Geochemical Environment

Water is very important for humans, as it is a solvent for metabolic products. Moreover, it is necessary for metabolism, biochemical and transport processes. The elemental status in persons depends on the geochemical environment and consumption of bioelements with food and water. The aim of the paper is to conduct a comprehensive assessment of chemical composition of drinking tap water in Khanty-Mansiysk and Salekhard. Materials and Methods. The chemical composition of 100 samples of drinking tap water was analyzed by atomic absorption spectrometry, spectrophotometry and capillary electrophoresis. All in all, there were 50 samples from Khanty-Mansiysk and 50 samples from Salekhard. The results were compared with Sanitary Rules and Norms 2.1.4.1074-01. Results. Drinking tap water in Salekhard contains a significantly higher concentration of iron, which is much above the maximum allowable concentration, if compared to water samples in Khanty-Mansiysk (p=0.03). In the cities under consideration, the water undergoes high-quality reagent-free treatment. However, the deterioration of the water supply networks in Salekhard is 3 times as high as in Khanty-Mansiysk. Calcium and magnesium concentration in water samples from Khanty-Mansiysk is 5.6 and 3.9 times lower than the MAC; in water samples from Salekhard calcium concentration is 6.3 (p=0.008) and magnesium concentration 4.6 (p<0.001) times lower than the MAC. Conclusion. The consumption of ultra-fresh drinking water leads to low intake of bioelements, which are a part of enzymes contributing to the human antioxidant defense and can result in manifestation of cardiovascular diseases. This is especially true for Salekhard with very soft drinking water and high iron concentration, which excess can exhibit prooxidant properties. Keywords: tap water, bioelements, northern region, antioxidants. Вода является важнейшим соединением для человека: необходима в качестве растворителя продуктов метаболизма и протекания обменных, биохимических и транспортных процессов. Элементный статус организма человека зависит от геохимического окружения и поступления биоэлементов с пищей и водой. Цель. Провести комплексную оценку химического состава водопроводной воды городов Ханты-Мансийск и Салехард. Материалы и методы. Методами атомно-абсорбционной спектрометрии, спектрофотометрии и капиллярного электрофореза проанализирован химический состав 100 проб водопроводной воды: по 50 из Ханты-Мансийска и Салехарда. Результаты сравнивали с СанПиН 2.1.4.1074-01. Результаты. В водопроводной воде Салехарда установлена превышающая ПДК и достоверно более высокая концентрация железа сравнительно с водой Ханты-Мансийска (р=0,03). При условии качественной безреагентной водоподготовки в изучаемых городах это обусловлено изношенностью водопроводных сетей в Салехарде, более чем в 3 раза превышающей этот показатель в Ханты-Мансийске. Концентрация кальция и магния в воде Ханты-Мансийска в 5,6 и 3,9 раза ниже ПДК; в воде Салехарда – в 6,3 (р=0,008) и 4,6 (р<0,001) раза ниже ПДК соответственно. Заключение. Употребление ультрапресной питьевой воды на фоне очень малого поступления с водой биоэлементов, входящих в состав ферментов антиоксидантной защиты организма человека, может привести к манифестации кардиоваскулярных заболеваний. Это особенно актуально для г. Салехарда с очень мягкой питьевой водой с повышенным содержанием железа, избыток которого может проявлять прооксидантные свойства. Ключевые слова: водопроводная вода, биоэлементы, северный регион, антиоксиданты.

Spatial and Temporal Variability of Surface Snowfall and Snowpack Chemistry in Central Ontario

1985 ◽  
Vol 7 ◽  
pp. 185-190 ◽  
Author(s):  
R.S. Schemenauer ◽  
P.W. Summers ◽  
H.A. Wiebe ◽  
K.G. Anlauf
Keyword(s):  
Chemical Composition ◽  
Chemical Structure ◽  
Precipitation Chemistry ◽  
Spatial And Temporal Variability ◽  
Vertical Variation ◽  
Ph Values ◽  
Pollutant Concentrations ◽  
The One ◽  
Physical And Chemical ◽  
Annual Deposition

The physical and chemical structure of the snowpack near North Bay, Ontario was examined during the winter of 1984. precipitation chemistry measurements were also made. A marked areal uniformity was noted in the layered structure of the snowpack and in the vertical variation of the chemical composition. In late January, pH values of the snowpack varied from ∼4.1 at the surface to ∼4.8 near the ground. After rain and a major thaw in February the pH was near 4.8 throughout. Nitrate concentrations exceeded those of sulfate in the snowpack. The molar concentration ratio of / was typically 0.5. Samples of precipitation from six sites had pH values ranging from 3.4 to 5.2. to equivalent ratios were &lt;1 in snow and near 1 or &gt;1 in rain. The chemical composition of the precipitation was closely related to the airmass trajectory. Southerly trajectories yielded the lowest pH values and highest pollutant concentrations. The one-month period from 20 January to 21 February had a deposition of 0.2 g m−2 and a deposition of 0.35 g m−2. For , this deposition would be about one-twelfth the expected annual deposition and for about one-fifth.

Effect of carbonation and probiotic addition on the physicochemical, microbiological and sensory characteristics of whey dairy beverage

2020 ◽  
Vol 87 (2) ◽  
pp. 255-258
Author(s):  
Carla Salete Jadão Alves ◽  
Simone Andreoti Mendes Floriano ◽  
Verônica Parassen Voltarelli ◽  
Christiane Maciel Vasconcellos Barros de Rensis ◽  
Tatiana Colombo Pimentel ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Lactobacillus Casei ◽  
Physicochemical Characteristics ◽  
Passion Fruit ◽  
Sensory Acceptance ◽  
Ph Values ◽  
Carbonation Process ◽  
Hedonic Scale ◽  
The Impact ◽  
Dairy Beverages

AbstractThis research communication addresses the impact of the addition of Lactobacillus casei and/or carbonation (CO2) on the chemical composition, physicochemical characteristics, probiotic survival, and sensory acceptance of passion-fruit flavored whey dairy beverages (70% milk/30% whey) during storage (30 d/4°C). The addition of Lactobacillus casei and/or carbonation did not impact on the chemical composition, pH values, and acceptance (flavor and overall impression) of the products, but increased the acidity, and decreased the aroma acceptance. The carbonation process did not affect the probiotic survival but decreased the acidity of the products during storage. It can be concluded that it is possible to develop a probiotic passion-fruit flavored carbonated whey dairy beverage with suitable chemical composition, acidity, sensory acceptance (>6 in 9-point hedonic scale) and probiotic viability (>7 log cfu/ml) that could be refrigerated stored for 30 d. This is the first report considering a probiotic non-fermented carbonated whey dairy beverage.

Chemical composition of salt lakes in East Transbaikalia (Russia)

2019 ◽  
Vol 103 ◽  
pp. 72-84 ◽  
Author(s):  
Svetlana V. Borzenko ◽  
Stepan L. Shvartsev
Keyword(s):  
Chemical Composition ◽  
Salt Lakes

scholarly journals Chemical equilibrium of groundwater with minerals of the host rocks in Upper Jurassic sediments (Arctic regions of Western Siberia)

2019 ◽  
Vol 98 ◽  
pp. 01037 ◽  
Author(s):  
Dmitry A. Novikov
Keyword(s):  
Chemical Composition ◽  
Chemical Equilibrium ◽  
Western Siberia ◽  
Upper Jurassic ◽  
The Arctic ◽  
Geochemical Environment ◽  
Rock System ◽  
Arctic Regions ◽  
Host Rocks ◽  
Mineral Changes

The results of thermodynamic calculations for a water-rock system in the Upper Jurassic deposits of the Arctic regions of Western Siberia are presented. In the area under investigation the groundwaters have been identified with mineralization up to 63.3 g/L and various chemical composition and genesis. Despite the long interaction with the rock (150-160 ma) equilibrium with endogenous minerals (albite, microcline and anorthite) is practically not observed. At the same time, groundwaters are in equilibrium with clay minerals and micas, such as: Caand Na-montmorillonites, kaolinite, paragonite, margarite, illite, muscovite and Mg-chlorite. The establishment of a balance of groundwater with primary aluminosilicate minerals is also affected by interactions with carbonate minerals. The differences in composition of groundwater in equilibrium with certain aluminosilicates and carbonates indicate that the mineral changes are formed from a solution of a strictly defined chemical composition in an appropriate geochemical environment.

scholarly journals Corrosive Environment Assessment and Corrosion-Induced Rockbolt Failure Analysis in a Costal Underground Mine

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qifeng Guo ◽  
Jiliang Pan ◽  
Min Wang ◽  
Meifeng Cai ◽  
Xun Xi
Keyword(s):  
Chemical Composition ◽  
Corrosion Rate ◽  
Time Dependent ◽  
Gold Mine ◽  
System Failure ◽  
Corrosive Environment ◽  
Support Design ◽  
Ph Values ◽  
Environment Assessment

As an effective ground-reinforcing system, rockbolts have been widely used in underground excavations. Corrosion of rockbolts has been one of the most reasons for rockbolts system failure. In this paper, the chemical composition and pH values of the groundwater in Sanshandao Gold mine are first tested. Corrosion of the slotted rockbolts used in roadways of the mine is analysed. The corrosion rate of rockbolts is evaluated based on experimental results from similar corrosive conditions. A time-dependent analytical model on anchoring force degradation caused by corrosion of the rockbolt is developed. Furthermore, the effects of corrosion rate and geometric parameters of the slotted rockbolts on anchoring force degradation are discussed. Suggestions on rockbolts support design in corrosive conditions are given. It has been found that, with the corrosion time increasing, the anchoring force between the rock and the rockbolt gradually decreases. The larger the corrosion rate is, the faster the anchoring force decreases. For long-term service roadways under corrosive conditions, a slotted rockbolt with a smaller radius and thicker wall can enhance the anchoring force.

Effects of pH Values of Hydrogen Peroxide Bleaching Agents on Enamel Surface Properties

2011 ◽  
Vol 36 (5) ◽  
pp. 554-562 ◽  
Author(s):  
B Xu ◽  
Q Li ◽  
Y Wang
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Composition ◽  
Ph Value ◽  
Negative Control ◽  
Enamel Surface ◽  
Control Group ◽  
Solution Ph ◽  
Peroxide Bleaching ◽  
Color Changes ◽  
Ph Values

SUMMARY This study investigated the influence of pH values of bleaching agents on the properties of the enamel surface. Sixty freshly extracted premolars were embedded in epoxy resin and mesiodistally sectioned through the buccal aspect into two parts. The sectioned slabs were distributed among six groups (n=10) and treated using different solutions. Group HCl was treated with HCl solution (pH=3.0) and served as a positive control. Group DW, stored in distilled water (pH=7.0), served as a negative control. Four treatment groups were treated using 30% hydrogen peroxide solutions with different pH values: group HP3 (pH=3.0), group HP5 (pH=5.0), group HP7 (pH=7.0), and group HP8 (pH=8.0). The buccal slabs were subjected to spectrophotometric evaluations. Scanning electron microscopy investigation and Micro-Raman spectroscopy were used to evaluate enamel surface morphological and chemical composition alterations. pH value has a significant influence on the color changes after bleaching (p&lt;0.001). Tukey's multiple comparisons revealed that the order of color changes was HP8, HP7&gt;HP5, HP3&gt;HCl&gt;DW. No obvious morphological alterations were detected on the enamel surface in groups DW, HP7, and HP8. The enamel surface of groups HCl and HP3 showed significant alterations with an erosion appearance. No obvious chemical composition changes were detected with respect to Micro-Raman analysis. Within the limitations of this study, it was concluded that no obvious morphological or chemical composition alterations of enamel surface were detected in the neutral or alkaline bleaching solutions. Bleaching solutions with lower pH values could result in more significant erosion of enamel, which represented a slight whitening effect.

scholarly journals Growth and Characterization of Organic Marine Dye Compound: 6-Amino-8α-methoxy-5-methyl-4,7-dioxo-1,1a, 2,4,7,8,8a,8b-octahydroazireno[2',3':3,4] pyrrolo[1,2-α]indol- 8-yl]methyl Carbamate

2011 ◽  
Vol 8 (4) ◽  
pp. 1797-1801
Author(s):  
M. Jayandran ◽  
V. Balasubramanian
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
Single Crystals ◽  
Harmonic Generation ◽  
Grown Crystal ◽  
Second Harmonic ◽  
Slow Evaporation ◽  
Ph Values ◽  
Crystalline Nature

Single crystals of 6-amino-8α-methoxy-5-methyl-4,7-dioxo-1,1a, 2,4,7,8,8a,8b-octahydroazireno[2',3':3,4]pyrrolo[1,2-α]indol-8-yl]methyl carbamate (Mitomycin), an organic marine dye material has been grown from solution by slow evaporation at ambient temperature. The growth of crystals has been carried out at various pH values and the growth was confirmed at pH 6. The chemical composition of the grown crystals was determined by the FTIR spectra. The crystalline nature and its various planes of reflections were observed by the powder XRD. The grain size is found to be 500 microns using SEM studies and the NLO activity of the grown crystal has been checked by second harmonic generation (SHG) test.

Sign in / Sign up

Export Citation Format

Share Document