New Data on Hydrogeochemical and Isotopic Composition of Natural Waters of the Baidar Valley (Crimean Peninsula)

—Results of study of natural waters of the Baidar valley (southwestern Crimean Peninsula) obtained during the 2018–2019 field works are presented. Major groundwater resources of the study area are confined to the Upper Jurassic aquifer complex, which serves as a recharge source for the aquifer systems of the Plain Crimean and the Azov–Kuban’ artesian basins and hydrogeologic folded region of the Crimean Mountains mega-anticlinorium. The regional waters are fresh and ultrafresh, predominantly of calcium bicarbonate composition, with TDS varying from 208 to 1269 mg/dm3. The study enabled their classification into eight geochemical groups: (1) waters of a regional fracture zone in carbonate-terrigenous rocks affected by continental salinization; (2) waters of a regional fracture zone affected by leaching of aluminosilicates and sulfide oxidation; (3) waters of a regional fracture zone dominated by sodium aluminosilicates in the fracture filling (long-term interaction in the water–rock system), affected by continental salinization; (4) regional fracture zones dominated by sodium aluminosilicates affected by anthropogenic continental salinization; (5) groundwaters in fracture–vein aquifers affected by leaching of aluminosilicates and sulfide oxidation; (6) fracture–vein aquifers affected by leaching of sodium aluminosilicates (long-term interaction in the water–rock system); (7) waters in fractured karst aquifers; and (8) surface waters subjected to continental salinization. Fracture karst waters, which were found to be most protected against human impact and continental salinization processes, are slightly alkaline (pH = 7.7), fresh (with average TDS = 444 mg/dm3), with low silicon concentrations (2.23 mg/dm3), and of calcium bicarbonate composition. Waters residing in regional fracture and fracture–vein zones are affected by continental salinization and anthropogenic load and are neutral to alkaline (pH = 7.1–8.6), predominantly fresh (TDS = 269–1269 mg/dm3), with average silicon concentrations of 4.61–4.70 mg/dm3, of calcium bicarbonate composition, with high concentrations of sulfate ion, magnesium, and sodium. The waters of the Chernaya River, Chernorechensk reservoir, and lakes, which are also affected by continental salinization, are slightly alkaline (pH = 8.3), brackish (TDS = 207–364 mg/dm3), with an average silicon concentration of 1.18 mg/dm3, of calcium bicarbonate composition, with high concentrations of chlorine ion, magnesium, and sodium. The calculated intensity of chemical-element migration in waters of the background composition follows the descending order: very strong, I17.7 > Br14.4; strong, Se2.83 > B2.22 > Sr1.46 > Sb1.12 > Be1.07 > Hg1.06; moderately strong, Zn0.74 > Mo0.50 > Li0.46 > Sc0.41 > Ag0.18 > As0.16 > Si0.123 > Ba0.122; weak, Cr0.10 > Cu0.096 > Bi0.080 > Sn0.068 > Tl0.067 > P0.062 > Ni0.043 > Ta0.040 > Ge0.034 > Cd0.028 > Fe0.026 > Rb0.024 > Co0.023 > Pb0.020 > W0.017 > V0.012; very weak (inert), Nb0.008 > Hf0.0033 > Mn0.0031 > La0.0029 > Cs0.0022 > Ti0.0018 > Ga0.0016 > Y0.0013 > Al0.0008 > Zr0.0008. All the studied waters are found to be of atmospheric origin and located along the global (GMWL) and local (LMWL) meteoric water lines. Their δ18O value varies from –9.9 to –3.3‰, and δD value, from –64.2 to –32.5‰. Sedimentary carbonate rocks, atmospheric carbon dioxide, organic compounds, and hydrolysis of aluminosilicate minerals serve as the source of δ13C bicarbonate ion in natural waters of the Baidar valley. Surface waters have a heavier carbon isotope composition (δ13C = –9.2 to –6.2‰), which is due to atmospheric CO2, plant growth, and associated microbial activity. Fracture karst waters are characterized by a lighter carbon isotope composition (δ13C = –12.8 to –11.0‰) because of their interaction with dispersed organic matter. Waters of the regional fracture and fracture–vein zones display the widest variation in δ13C (–15.5 to –6.9‰), which is associated with a mixed type of “isotope supply” to the waters. A complex hydrogeochemical field that has formed in the Baidar valley tends to be increasingly affected by the anthropogenic factor.

Virucidal Effect of the Mesoscopic Structure of CAC-717 on Severe Acute Respiratory Syndrome Coronavirus-2

Here, the virucidal effect of calcium bicarbonate with a mesoscopic structure (CAC-717) on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was determined. Assays showed that CAC-717 had a strong virucidal effect on all examined SARS-CoV-2 isolates, including variant strains. The viral infectivity decreased within 15 s, and the virucidal activity of CAC-717 at a 1:49 ratio was similar to that of ethanol disinfectant. CAC-717 neutralization eliminated this virucidal effect, indicating that the alkaline condition of CAC-717 is important for virus inactivation and is an indicator of its mesoscopic structure and virucidal activity. The virucidal effect was observed in the presence of organic matter (bovine serum albumin). CAC-717 is a non-invasive and non-flammable substance with a low environmental burden, and its usefulness as a novel disinfectant has been confirmed.

Groundwater chemistry: a case study of the Mesta River Basin

The present study describes the hydrochemistry of ground waters found in the Mesta River Basin, located in the south-western part of Bulgaria. The groundwater’s composition can be expressed as follows: Ca2+ > Na+ > Mg2+ > K+; Ca2+ > Mg2+ > Na+ > K+ in equivalent units for the cations, and HCO3– > SO42– > Cl– in equivalent units for the anions. The chemical composition of the studied groundwater can be described as calcium-bicarbonate. The calcium ions make up from 17.90% to 38.62% (30.18% on average), and the bicarbonate ions make up from 35.30% to 48.98% (43.70% on average) of all ions. Taken together, the calcium and bicarbonate ions make up from 61.44% to 87.60% (73.88% on average) of all ions. The groundwater itself is of slightly alkaline nature, having pH of 7.3 to 8.6, and TDS of 67 mg/l to 611 mg/l. One groundwater sample from the Mesta River catchment area was found to be of the low-mineralized type (TDS = 193 mg/l) alkaline water (pH = 9.8) in the Mesta Lowlands – the Banichan groundwater mineral source. The water can be described as sodium-bicarbonate, with sodium ions making up to 93.5% of the cations, and bicarbonate ions – 69.6% of the anions. Out of all ions, the sodium ions were found to be 48%, and the bicarbonate ions – 33.86%. The sequence of ions is in the following order: Na+ > Ca2+ > Mg2+ > K+, and HCO3– > Cl– > SO42– > CO32–.

Electrolytes in the ICU

Electrolyte disorders is an imbalance of certain ionized salts (sodium, potassium, calcium, bicarbonate, chloride) in the blood. Healthcare providers should be familiar with the principles of electrolyte physiology and pathophysiology. Disturbances in sodium homeostasis are primarily caused by volume abnormalities leading to primarily neurologic symptoms. Dyskalemias frequently present with cardiac manifestations therefore should be treated promptly before evaluating its cause. Ion deficiencies such as hypocalcemia, hypomagnesemia and hypophosphatemia should be corrected as they are associated with increased adverse events in critically ill patients.

Hydrogeochemistry and hydrogeology of a fractured urban aquifer in the metropolitan region of Florianópolis, Southern Brazil

This paper was carried out through database of hydrogeological information of tubular wells based on the Groundwater Information System (SIAGAS) from the Geological Survey of Brazil (CPRM). The geology of the study area shows two main domains, a complex Crystalline Precambrian Shield partially covered by Quaternary sediments. Two main regional directions of tectonic lineaments were defined using satellite images with NE-SW and NW-SE orientations. The average discharges and specific capacities of the wells show values of 13.1 m 3 /h and 0.59 m 3 /h/m respectively. NW-SE linear structures were more productive than NE-SW, however the highest discharge values and the highest average (15.6 m 3 /h) are related to abstractions influenced by both directions simultaneously. Serra do Tabuleiro Granite is the lithology with the greatest productive potential in the region, followed by São Pedro de Alcântara Granite and the Granite-Gneiss-Migmatitic Complex. Sodium bicarbonate and calcium bicarbonate waters are the two main hydrochemical groups that occur in the region. The dissolution of calcium carbonate filling the fractures of the rocks is the main source responsible for the alkalinity of the water. The cationic proportion is defined by Na + > Ca 2+ > Mg 2+ > K + . In some wells, the increasing of Total Dissolved Solids (TDS) is probably related to the contribution of adjacent Quaternary porous aquifers deposited under marine influence.

NICKEL AND COPPER MIGRATION FORMS OF ULTRAFRESH WATERS IN THE KOLA REGION CENTRAL PART

The article presents the waters study results, the composition of which is formed in various hydrogeochemical and ecological conditions. All investigated waters are ultrafresh: TDS of streams and springs does not exceed 30 mg/l, water of Lake Imandra at sampling points is 40 and 73 mg/l. All waters are calcium bicarbonate, but the lake’s waters have an increased content of sulfate ion, chloride ion, and especially sodium. This composition is due to the influence of wastewater from the Kola MMC. It is shown that the 7 km stream is mainly groundwater discharge; however, judging by the concentrations of heavy metals and aluminum, the lateral soil water runoff also takes part in the formation of the stream’s water composition. For all studied waters, the gross concentrations of Ni and Cu hardly change after filtration through a membrane filter with a pore size of 0.45 μm, that is, these metals migrate in a dissolved form (a combination of colloidal and truly dissolved forms). The similarity of the results of determining the migratory forms of Ni and Cu in ultra-fresh waters by experimental and calculation methods is shown. Therefore, according to the assessment of the ratio of suspended, colloidal and truly dissolved forms of copper and nickel based on the results of an experiment using filtration and equilibrium dialysis, in the waters under consideration, the truly dissolved form of migration of Ni and Cu is predominant. The application of physicochemical modeling using the HydroGeo software package made it possible to show that nickel migrates mainly in the form of the Ni2+ ion, and copper in combination with the organic ligands Cu(FА) and Cu(FА2)2-. In addition, it was found that with an increase in the pH value of waters, the proportion of complex compounds increases and the amount of simple ions Ni2+ and Cu2+ decreases

The Effect of Long-Term Antihypertensive Therapy on the Change in Secretion and Calcium, Bicarbonate and Phosphate Ion Concentration in Non-Stimulated and Stimulated Saliva

Objective: The aim of this study was to evaluate the amount of saliva secreted and calcium, bicarbonate, and phosphate ion concentration in patients receiving antihypertensive for five years or over five years (patient group) and in healthy patients (control group). Material and methods: The patient or experimental group included 31 subjects who were admitted to a cardiovascular clinic and had been receiving an antihypertensive drug therapy for more than five years. The control group included 31 healthy subjects. The measured amount of saliva was further used to determine the calcium, phosphate and bicarbonate ion concentration values. Calcium and phosphate ions were determined spectrophotometrically, while bicarbonate ions were determined by titration. Results: A two-waytest (Student’s test) was used to compare the values of variables. The amount of excreted saliva was statistically significantly lower in the patient group in non-stimulated (1.739 mL/5 min) and stimulated saliva (3.594 mL/5 min). Calcium ion concentration was statistically significantly lower in patient group in resting saliva (6.143 mg/dL). Bicarbonate and phosphate ion concentration in patient group was statistically significantly higher in non-stimulated (bicarbonate ion = 14.041 mmol/L, phosphate ion = 2.818 mmol/L) and stimulated saliva (bicarbonate ion = 10.872 mmol/L, phosphate ion = 1.454 mmol/L), respectively. Conclusion: A reduced amount of saliva and calcium ion concentration indicates the possibility of a higher frequency of hard dental tissue demineralization process. On the contrary, the increase in the phosphate and bicarbonate ion concentration in the patient group affects the regulation of acid-base balance, thus having a preventive effect.

A review of the geology and origin of CO2 in mineral water springs in east Belgium

Naturally CO2-rich mineral water springs (pouhons) in east Belgium occur in the context of the Rhenohercynian domain of the Variscan fold-and-thrust belt, mostly within the Cambro-Ordovician Stavelot-Venn Massif. The origin of the CO2 is still unclear, although different hypotheses exist. In this review study, we show pouhon waters are of the calcium bicarbonate type (~310 mg/l HCO3- on average), with notable Fe (~15 mg/l) and some Ca (~43 mg/l). Pouhon waters are primarily meteoric waters, as evidenced by H and O isotopic signature. The δ13C of CO2 varies from -7.8 to +0.8‰ and contains up to ~15% He from magmatic origin, reflecting a combination of carbonate rocks and mantle as CO2 sources at depth. Dinantian and Middle Devonian carbonates at 2–6 km depth could be potential sources, with CO2 generated by dissolution. However, carbonates below the Stavelot-Venn Massif are only predicted by structural models that assume in-sequence thrusting, not by the more generally accepted out-of-sequence thrust models. The mantle CO2 might originate from degassing of the Eifel magmatic plume or an unknown shallower magmatic reservoir. Deep rooted faults are thought to act as preferential pathways. Overall low temperatures of pouhons (~10 °C) and short estimated residence times (up to 60 years) suggest magmatic CO2 is transported upwards to meet infiltrating groundwater at shallower depths, with partial to full isotopic exchange with carbonate rocks along its path, resulting in mixed magmatic-carbonate signature. Although the precise role and interaction of the involved subsurface processes remains debatable, this review study provides a baseline for future investigations.

The analysis of planktonic algae structure in the Volga and Kama rivers (Republic of Tatarstan)

The paper presents the results of a comparative analysis of planktonic algae structure in the Volga and Kama rivers at the confluence of the Kuibyshev reservoir. The author has also assessed the trophic state of the studied river sections in 2012. The hydrochemical regime of the Kuibyshev reservoir is heterogeneous and is determined by the chemical composition of the Volga and Kama waters, which differ in the ratio of ions and mineralization. The ionic composition of the Kama waters is often dominated by sulfates. The salinity depending on the season and water content of the year ranges from 168 to 674 mg/l. The Volga waters contain calcium bicarbonate and have a lower mineralization (120130 mg/l). The variability of the incoming water, the amount of runoff, the degree of volume drawdown within water bodies and groundwater inflows primarily affect the conditions for planktonic algae existence. In the phytoplankton of the Volga and Kama rivers (areas before their confluence in the Kuibyshev Reservoir), 123 taxa of algae were identified during the 2012 growing season. The waters of the Volga River have a higher species diversity (107 species). The phytoplankton of the Kama River is less diverse (76 species). In the seasonal dynamics of phytoplankton in the studied river sections, two peaks of abundance and biomass are observed by the middle of summer and at the end of it, when the maximum values of abundance and biomass are reached. The waters of the investigated sections of the Volga River is characterized by a complex of phytoplankton of blue-green, diatoms and green algae, while the Kama River is dominated by diatom phytoplankton. In summer and autumn the blooming of water in both rivers is due to the massive development of blue-green algae of the genera Microcystis, Aphanizomenon, Anabaena, Oscillatoria. The waters of the Volga and Kama rivers in 2012 during the study period corresponded to the mesasaprobic type and moderately polluted zone; the waters of the Kama River had higher saprobity indices. The trophic status of the rivers under consideration in the study area was mostly related to the eutrophic type; during the periods of maximum reproduction of blue-green algae to the hypereutrophic type.