Magnesium Ion Concentration Research Articles

Assessment of sachet water quality in Kumasi, Ghana

This study assessed the physicochemical and microbiological quality of sachet drinking water samples in Kumasi, a major city in Ghana. Samples were collected from various sources within the city. Physicochemical properties, including pH, total dissolved solids, and concentrations of calcium, sodium, potassium, and magnesium ions, were analyzed following established protocols. Additionally, fluoride concentration was determined. The assessment criteria for water quality were based on the World Health Organization’s and the Ghana Standards Authority’s recommended standards for drinking water. The samples were also subjected to microbial analysis to detect the presence of E. coli and coliforms, and to evaluate microbial quality. The findings indicated that most physicochemical properties of the samples met the World Health Organization’s standards for safe drinking water, except for the slightly acidic pH. Total dissolved solids and the concentrations of calcium, sodium, potassium, fluoride and magnesium ions were within acceptable ranges. Strong positive correlations were observed among various physicochemical parameters of sachet water. However, microbial analysis revealed that 67% of the samples were contaminated with pathogenic microorganisms, including E. coli and coliforms, indicating poor microbiological quality. While sachet water samples generally meet physicochemical safety standards, addressing microbial quality is essential to ensure the safety of drinking water in Kumasi.

Systematic Review and Meta-Analysis to Estimate a Reference Range for Circulating Ionized Magnesium Concentrations in Adult Populations

BackgroundThere is a lack of consensus on a reference range for ionized magnesium (iMg2+) in blood as a measure of the status of circulating iMg2+ for the screening of populations. ObjectivesWe estimated the reference range of iMg2+ levels for healthy adult populations and the ranges for populations with cardiovascular disease (CVD), type 2 diabetes, hypertension, and renal disease. We also estimated 95% ranges for circulating magnesium (Mg) in healthy and those with cardiometabolic diseases. MethodsWe searched Ovid MEDLINE, Cochrane Central Register of Controlled Trials, and Embase through 24 July, 2020 to identify articles. We included English, peer-reviewed, randomized controlled trials, prospective and retrospective cohort studies, case-control studies, and cross-sectional studies that measured iMg2+ in blood or circulating Mg at baseline. The protocol was registered on PROSPERO (CRD42020216100). Estimated ranges were calculated by employing a frequentist random-effects model using extracted (or calculated) means and SDs from each included study. We determined the 95% confidence interval of the pooled mean. ResultsA total of 95 articles were included with 53 studies having data for healthy participants and 42 studies having data for participants with cardiometabolic diseases. The estimated reference range for iMg2+ for healthy populations was 0.40–0.68 mmol/L, 0.38–0.64 mmol/L for CVD, 0.34–0.66 mmol/L for type 2 diabetes, 0.39–1.04 mmol/L for hypertension, and 0.40–0.76 mmol/L for renal disease. For circulating Mg, the estimated range was 0.72–1.0 mmol/L for healthy adults, 0.56–1.05 mmol/L for CVD, 0.58–1.14 mmol/L for type 2 diabetes, 0.60–1.08 mmol/L for hypertension, and 0.59–1.26 mmol/L for renal disease. ConclusionsEstimated reference ranges for cardiometabolic disease states for both iMg2+ and circulating Mg were broad and overlapped with the estimated range for healthy populations (0.40–0.68 mmol/L). Further studies should evaluate whether iMg2+ can be used as a biomarker of cardiometabolic disease.

EXAMINATION OF THE CHEMICAL COMPOSITION OF SPRING WATERS IN AKETI VILLAGE OF LANCHKHUTI MUNICIPALITY


 
 
 
 For the first time the hydrochemical examination of the spring waters of the village of Aketi of Lanchkhuti municipality was conducted. The content of magnesium and calcium ions, hydrocarbonate ions, chloride ions, sulfate ions, dry balance, permanganate oxidation, total iron ions, dissolved oxygen and carbon dioxide is determined. The content of total iron ions, dissolved oxygen and carbon dioxide. Relatively simple and fast chemical and physico-chemical methods with good reproducibility were selected for determination. Biogenic substances were determined by the photometric method.
 Objective: We aimed to study the chemical composition of the spring waters of Aketi village of Lanchkhuti municipality. We determined the following: the content of magnesium and calcium ions, hydrocarbonate ions, chloride ions, sulfate ions, dry balance, permanganate oxidation, total iron ions, dissolved oxygen and carbon dioxide in the spring waters of Aketi village of Lanchkhuti municipalityThe relevance of the issue lies in the fact that the content of the above-mentioned ions was determined for the first time in the given waters, for which highly sensitive methods were selected.
 
 
 

Enhanced strategies for phosphate recovery from urine by magnesium galvanic process

Magnesium galvanic process (MGP) can be applied to recover phosphate from source-separated urine. However, information on how the urine matrix affects MGP performance is limited. Therefore, this study investigated the mechanism of phosphate recovery by MGP in synthetic and real urine matrixes. Our results showed that the major components in urine (i.e., NH4+, Cl−, and HCO3−) all exhibited acceleration effects on corrosion of Mg plate. However, the underlying action mechanism of each component was distinct. Ammonium facilitated the conversion from MgO to Mg(OH)2, chloride complexed with Mg2+ ions, and bicarbonate led to complexation as well as formation of MgCO3. Furthermore, our results revealed an interesting aspect where although bicarbonate alone accelerated the corrosion of Mg plate, its coexistence with other ions inhibited overall performance due to the blocking effect of formed MgCO3 on chloride penetration and reduction in free magnesium ion concentration. After elucidating the interaction of NH4+, Cl−, and HCO3− on the passive layer of the Mg plate, we proposed to pretreat urine with HCl, which resulted in a significant enhancement in current production and phosphate recovery. This improved MGP was further tested in a continuous flow reactor, which recovered over 95% of phosphate in real urine for more than 1 h. The phosphate precipitates were confirmed as high purity struvite. Generally, the improved MGP, which simultaneously produced Mg2+, dihydrogen, and electricity with no energy input, is a promising sustainable and green alternative for phosphate recovery from source-separated urine.

The Stability of Analytes of Ionized Magnesium Concentration and Its Reference Range in Healthy Volunteers.

This study aimed to determine the stability of refrigerated analytes of iMg concentration at different time intervals and to establish iMg reference range in a cohort of healthy Omani volunteers (≥18 years). The concentrations of iMg were measured using the direct ion-selective electrode technique. Pearson's and Lin's concordance correlation coefficients along with the Bland-Altman plot were used to assess the levels of agreement between iMg concentrations of fresh and refrigerated blood samples at different time intervals. The study included 167 volunteers (51% females) with a median age of 21 (range: 20-25) years. The median, 2.5th, and 97.5th percentiles for fresh iMg reference ranges were 0.55, 0.47, and 0.68 mmol/L, respectively. The overall agreement between the fresh and refrigerated iMg concentrations was poor (rho-c = 0.51; p < 0.001). However, according to Altman's definition, iMg concentrations of the refrigerated samples for a period of ≤1 h had an excellent correlation with the fresh iMg concentrations (Lin's rho-c = 0.80), with a small average bias difference of 0.009 (95%CI; -0.025-0.043). A cut-off refrigeration period within ≤1 h at 2-8 °C can be considered an alternate time frame for the gold standard measurement (fresh or within 0.5 h).

A SAM analogue-utilizing ribozyme for site-specific RNA alkylation in living cells

Post-transcriptional RNA modification methods are in high demand for site-specific RNA labelling and analysis of RNA functions. In vitro-selected ribozymes are attractive tools for RNA research and have the potential to overcome some of the limitations of chemoenzymatic approaches with repurposed methyltransferases. Here we report an alkyltransferase ribozyme that uses a synthetic, stabilized S-adenosylmethionine (SAM) analogue and catalyses the transfer of a propargyl group to a specific adenosine in the target RNA. Almost quantitative conversion was achieved within 1 h under a wide range of reaction conditions in vitro, including physiological magnesium ion concentrations. A genetically encoded version of the SAM analogue-utilizing ribozyme (SAMURI) was expressed in HEK293T cells, and intracellular propargylation of the target adenosine was confirmed by specific fluorescent labelling. SAMURI is a general tool for the site-specific installation of the smallest tag for azide-alkyne click chemistry, which can be further functionalized with fluorophores, affinity tags or other functional probes.

The combined effect of highly variable DC current – Simulated from solar irradiance data – And electrolyte quality on zinc electrowinning

This paper is the second in a series of two papers focusing on the applicability of highly variable direct current (DC) for the production of high quality cathodes by electrowinning. Different current profiles were simulated from solar irradiance data and then applied to electrowinning cell using a precision programmable power supply. The simulated DC current was applied to the zinc electrowinning process, which was chosen as a case study due to its intensive energy consumption. The present work discusses the combined effect of highly variable current with the concentration of magnesium ions (Mg2+) in the zinc sulfate electrolyte. The impact of this impurity is relevant due to the complex mineralogy of the zinc ores available for processing (i.e., magnesium is one of the major elements contained in low-grade silicate ores). The results showed that even over a wide range of applied current densities (highest average value = 697 A m−2; highest peak value = 1486 A m−2), the average values of current efficiency calculated for the process, according to the different types of solar irradiance variability, are comparable. The lowest value (90.3% for intermittent day) could be explained by high amplitude variations in the intensity of the current density, which enhances the hydrogen evolution rate. The average values of current efficiency decreased with increasing impurity concentration in the electrolyte; decreases of 0.8–2.0% units in the average value of current efficiency were calculated at 15 g L−1 Mg2+. At this concentration, an increase of 2.1–6.8% in the average values of specific energy consumption was calculated, which was explained by the observed decrease in current efficiency and a slight increase in the cell voltage due to a decrease in the electrolyte conductivity. The deposits formed in the presence of 15 g L−1 and 30 g L−1 Mg2+ in the electrolyte showed a relatively greater number of pores, which, however, did not cause them to fracture or break during stripping.

Effects of saline water with different concentrations of calcium and magnesium ions on emitter clogging in drip irrigation integrated water–fertilizer system

AbstractThe application of saline water in drip irrigation is severely constrained due to its high salt content, which causes precipitation and emitter clogging. Therefore, the effects of calcium and magnesium ions at 100, 150 and 200 mg/L in saline water coupled with humic acid nitrogen fertilizer on emitter clogging were studied. Compared with ground saline water, all treatments significantly increased the emitter clogging risk. In the calcium and magnesium ion treatment groups, clogging fouling increased by 23.94–58.35 and 14.55–51.21 mg/cm2, the discharge variation ratio (Dra) decreased by 22%–59% and 14%–49%, and the Christiansen coefficient of uniformity (CU) decreased by 29%–79% and 15%–74%, respectively. Higher ion concentrations caused more clogging. Saline water with a high calcium content caused more clogging. Under similar concentration conditions, the Dra and CU in high magnesium saline water were 9%–32% and 8%–51% higher, respectively. In addition, the increase in magnesium ion concentration changed the crystal form of carbonate, slowed the formation rate of precipitated dirt and significantly reduced the carbonate content by 19%–40%. Our results provide support for the popularization of saline water drip irrigation systems.

Catalytic Transfer Hydrogenation Performance of Magnesium-Doped ZrO2 Solid Solutions

This is the first study to investigate the activity of a solid solution containing magnesium ions in a zirconia matrix in the catalytic transfer hydrogenation (CTH) of acetophenone with 2-pentanol. The results have shown that magnesium oxide is very highly active in CTH when physically mixed with zirconia. However, the same concentration of Mg2+ ions (Mg:Zr = 3:97) inserted into a zirconia lattice did not yield high activity in CTH. A higher concentration of Mg2+ ions (5%) was also tested in the two types of systems, i.e., a physical mixture of oxides and a solid solution. The increase in the concentration of Mg2+ ions in the physical mixture led to a pronounced increase in the activity of the system, whereas in the case of the solid solution it led to a slight decrease in activity. The impact of the zirconyl salt used in the synthesis was also examined, but showed little effect on the properties and activity of the systems. The study has also shown that the increase of the concentration of magnesium ions caused a decrease in the m-ZrO2 to t-ZrO2 ratio. Nevertheless, the rate of heating had an even bigger effect on this ratio.

Fabrication of Electrochemical Sensor for the Detection of Mg(II) Ions Using CeO2 Microcuboids as an Efficient Electrocatalyst

In human blood serum, the concentration of magnesium ions typically ranges from 0.7 mM to 1.05 mM. However, exceeding the upper limit of 1.05 mM can lead to the condition known as hypermagnesemia. In this regard, a highly sensitive and selective electrochemical sensor for Mg(II) ion detection was successfully fabricated by immobilizing cerium oxide (CeO2) microcuboids, synthesized via microwave radiation method, onto the surface of glassy carbon electrode (GCE). Cyclic voltammetry studies revealed the exceptional electrocatalytic effect of CeO2 microcuboid-modified GC electrode, particularly in relation to the irreversible reduction signal of Mg(II). The microcuboid-like structure of CeO2 microparticles facilitated enhanced adsorption of Mg(II) ion (Γ=2.17×10−7mol cm−2) and electron transfer (ks=8.94 s−1) between the adsorbed Mg(II) ions and GCE. A comprehensive analysis comparing the performance characteristics of amperometry, differential pulse voltammetry, cyclic voltammetry, and square wave voltammetry was conducted. The square wave voltammetry-based Mg(II) sensor exhibited remarkable sensitivity of 2.856 μA mM−1, encompassing a broad linear detection range of 0–3 mM. The detection and quantification limits were impressively low, with values of 19.84 and 66.06 μM, respectively. Remarkably, the developed electrode showed a rapid response time of less than 140 s. Multiple linear regression and partial least squares regression models were employed to establish a mathematical relationship between magnesium ion levels and electrochemical parameters. Notably, the proposed sensor exhibited excellent anti-interferent ability, repeatability, stability, and reproducibility, enabling the fabricated electrode to be used effectively for Mg(II) ion sensing in real-world samples.

Optimization of Biomass Cultivation from Tuber borchii and Effect of Additives on Triterpenoid Production

Edible fungi are renowned for producing biologically active secondary metabolites that possess anti-tumor activity, protect the liver and have other benefits. The cultivation of truffle mycelia through submerged fermentation has gained interest in the production of metabolites for bio-medicinal purposes. In the present study, Tuber borchii was cultivated by submerged fermentation to produce both biomass and triterpenoids. Various additives, including palmitic acid, stearic acid, linoleic acid, chitosan, CaCl2 and limonene, were investigated to enhance triterpenoid production. It was observed that increasing the medium’s linoleic acid concentration to 1 g/L increased the production of triterpenoids to 129.29 ± 6.5 mg/L, which was 2.94 times higher than the control. A number of variables, including potassium and magnesium ion concentrations and carbon and nitrogen sources and concentrations, were considered to ascertain the ideal conditions for T. borchii growth in submerged fermentation. The best concentrations for glucose, yeast extract, peptone, malt extract, KH2PO4 and MgSO4·7H2O in submerged fermentation were 19.45, 4.58, 7.91, 5.3, 0.58 and 0.82 g/L, respectively, according to response surface methodology. Validation analysis revealed that the experimental values and the predicted values were in good agreement. Under ideal circumstances, the maximum dry cell weight (2.980.18 g/L), which was 1.39 times greater than the control, was attained. Finally, the addition of 1.5 g/L linoleic acid on day 14 to the optimal medium elevated the triterpenoid production to 212.63 ± 16.58 mg/L, which was a 4.84-fold increase compared to the control.

NaBH4-Mediated Co-Reduction Synthesis of Glutathione Stabilized Gold/Silver Nanoclusters for Detection of Magnesium Ions

The content of magnesium ions (Mg2+) in drinking water is relatively high and the excessive Mg2+ ingestion may lead to pathological lesions in the human body system. At present, the detection of Mg2+ still relies on costly devices or/and complex organic fluorescence probes. To solve this problem, this work proposed a NaBH4-mediated co-reduction strategy for the synthesis of glutathione-stabilized bimetallic AuAg nanoclusters (GSH@AuAg NCs) with performance recognition to Mg2+. The preparation of GSH@AuAg NCs was simple and rapid and could be performed at mild conditions. The reaction parameters and sampling orders were optimized to understand the formation mechanism of GSH@AuAg NCs. The GSH@AuAg NCs exhibited a sensitive “light on” fluorescence response to Mg2+ due to the re-molding of the interfacial physicochemical environment following the Mg2+ coordination, which affected the surface charge transfer process, and thus led to a novel method for fluorescence detection of Mg2+ with admirable selectivity for Mg2+. The proposed method showed a detection limit of 0.2 μM, and its practical utility for the detection of Mg2+ in a real sample of purified drinking water was also demonstrated, confirming its practicability in monitoring the Mg2+ concentration in drinking water.

Compost Made from Cow Dung and Sawdust Improves the Physicochemical and Biochemical Properties of the Soil, the Production and the Nutritional Quality of Tomatoes (Lycopersicon esculentum Mill.)

The effect of a compost based on cow dung and sawdust on the production and nutritional quality of tomatoes was evaluated. The compost was prepared by mixing the different constituents in variable mass/mass proportions: 25/75, 50/50, 75/25 and 100/0. The experimental device for growing tomatoes in pots was made in completely randomized random blocks with 5 repetitions, and 3 compost/soil mass/mass proportions (5%, 10% and 15%) for each variant. The physicochemical, biological and biochemical parameters of the compost and amended soils, the production and the nutritional quality of the fruits were evaluated. The C3 variant of compost showed the highest pH (9.88 ± 0.01); C4 presented the highest C/N ratio (21.45 ± 0.42); C2 showed the highest contents of nitrogen, phosphorus, magnesium, calcium, potassium, and sodium, the highest values of bacterial and fungal flora and cellulase, protease, β-glucosidase, acid and alkaline phosphatase activities. Analysis of amended soils showed that: C2 (15%) has the highest pH. C1 (10%) presented the highest C/N ratio (42.12 ± 3.98) and C3 (15%) the highest contents of nitrogen, magnesium ions and calcium. C4 (15%) presented the highest potassium and sodium content. The compost significantly improved tomato production. The C2 (15%) compost was the most productive with 154 ± 3.00 fruits, 10 times more than the tomato produced with chemical fertilizer (15.00 ± 1.00 fruits). The Biological tomato showed higher proportions of ash, total sugars, lycopene, vitamin C and polyphenols than the chemical tomato. The results show that the organic treatment improved the physicochemical, biological and biochemical properties of the soil, the production and the nutritional quality of the tomato. The compost constitutes therefore an efficient method for sustainable agriculture.

Proximate, Nutrient Composition and Glycemic Index of Pearl Millet-Acha-Moringa Blend

Globally, grains can be regarded as the daily source of diets for many populations. They constitute cereals, pseudocereals and legume and are majorly the seeds of plants. They are made up of a wide variety of macronutrients that are vital to human diet, those nutrients are not limited to carbohydrates, but also proteins lipids and micronutrients such as vitamins and minerals. Grains can be consumed as a source of dietery fibre and bioactives. This research is aimed at formulating a diet using whole grains and cray fish and also to determine the nutrients composition of the diet and its Glycemic Index. A diet was formulated using whole Pearl millet, whole Hungary rice, moringa leaves and cray fish. The Glycemic Index of the diet and the nutrients composition of the formulated diet such as % Fat, % Ash, % Moisture, %Fiber and Vitamin E were determined. Iron and magnesium ions concentration was determined using Atomic Absorption Spectrophotometry while calcium ion was determined using Flame Photometry. The result showed that the blend contains 6.31% moisture, 1.24% ash, 1.50% fat, 12.06% protein, 3.22% fibre, 75.66% carbohydrate, 50.22 mg Vitamin E, 1.37 mg Magnesium (Mg), and the Glycemic Index was 67.7%.

XdfA, a novel membrane-associated DedA family protein of Xanthomonas campestris, is required for optimum virulence, maintenance of magnesium, and membrane homeostasis.

Xanthomonas campestris is an important member of the Xanthomonas group of phytopathogens that causes diseases in crucifers. In X. campestris, several virulence-associated functions, including some belonging to unknown predicted functions, have been implicated in the colonization and disease processes. However, the role of many of these unknown predicted proteins in Xanthomonas-host interaction and their exact physiological function is not clearly known. In this study, we identified a novel membrane-associated protein belonging to the DedA super family, XdfA, which is required for virulence in X. campestris. The DedA family of proteins are generally ubiquitous in bacteria; however, their function and actual physiological role are largely elusive. Characterization of ∆xdfA by homology modeling, membrane localization, and physiological studies indicated that XdfA is a membrane-associated protein that plays a role in the maintenance of membrane integrity. Furthermore, functional homology modeling analysis revealed that the XdfA exhibits structural similarity to a CorA-like magnesium transporter and is required for optimum growth under low magnesium ion concentration. We report for the first time that a putative DedA family of protein in Xanthomonas is required for optimum virulence and plays a role in the maintenance of membrane-associated functions and magnesium homeostasis. IMPORTANCE Bacterial DedA family proteins are involved in a range of cellular processes such as ion transport, signal transduction, and cell division. Here, we have discussed about a novel DedA family protein XdfA in Xanthomonas campestris pv. campestris that has a role in membrane homeostasis, magnesium transport, and virulence. Understanding membrane and magnesium homeostasis will aid in our comprehension of bacterial physiology and eventually will help us devise effective antimicrobial strategies to safeguard horticulturally and agriculturally important crop plants.

The effect of addition of K2ZrF6 on the structures and properties of AZ31 magnesium alloy MAO coating

It is a challenge to improve the corrosion rate and blood compatibility of biomedical magnesium alloy implants in human body. Scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) were used to study the Properties of K2ZrF6 modified AZ31 magnesium alloy composite coating. The corrosion behavior of the sample in simulated body fluid (SBF) was evaluated by hydrogen evolution corrosion, potentiodynamic polarization cur ve and electrochemical impedance spectroscopy. The results show that the corrosion resistance of magnesium alloy is significantly improved by composite coating. The wettability test shows that K2ZrF6 greatly improves the biocompatibility of MAO coating on magnesium alloy. The hemolysis test shows that the composite coating makes magnesium alloy have low hemolysis rate. The increase of PH value and magnesium ion concentration in solution caused by corrosion of magnesium alloy can be adjusted by adding K2ZrF6. The corrosion resistance mechanism of MAO coating on K2ZrF6 modified magnesium alloy was discussed. In this experiment, the optimum amount of K2ZrF6 is 4 g/L.

Novel polylactic acid porous scaffold reinforced with oriented magnesium wires for potential bone repair application

Polylactic acid porous scaffold oriently reinforced by magnesium wires (PLA-Mg) for bone repair was proposed in this paper. Ca-P deposition layer formed on the surface of Mg wires in PLA-Mg after immersion, which illustrated that PLA-Mg had good ability of mineralization in vitro. In PLA-Mg, the corrosion of the Mg wire end was higher than that of the middle regions in Mg wire during immersion. Uniform and long-term release of Mg2+ in PLA-Mg followed exponential rules of decline, which could be predicted that the final concentration of magnesium ions (C(Mg2+)) of PLA-Mg during immersion could reach 42.14 ppm, which was among the range of normal physiological and pathological conditions. Besides, the effect of pH on the hydrolysis of PLA in PLA-Mg surpassed that of C(Mg2+), improving the crystallinity of PLA in immersed PLA-Mg with an increase of 39.6 % compared to that in the unsoaked PLA. Compressive strength of PLA-Mg could reach 2.07 ± 0.25 MPa, which was greatly improved in contrast to that of pure PLA. After immersion, the stability of Mg wires in immersed PLA-Mg was higher than that in the unsoaked one. These results could provide references for developing potential porous composite scaffolds towards bone repair.

Influence of the Invasive Earthworm Eisenia nana (Lumbricidae) on the Content of Water-Soluble Forms of Cations (NH4+, K+, Na+, Mg2+, Ca2+) in Soil

Using a field simulation experiment in mesocosms, the influence of epi-endogeic earthworms was assessed, invasive E. nana and native E. nordenskioldi (in monopopulations and when kept together), on the availability of cations (NH4+, K+, Na+, Mg2+, Ca2+) in soil. A significant effect of both species on the increase in the content of sodium ions in the 10–15 cm soil layer relative to the control without worms, differences between the E. nana and E. nordenskioldi monovariants in the content of magnesium and calcium ions in the 0–5 cm layer, and a significant effect of the interaction of species on an increase in the availability of ammonium in the 20–30 cm layer.

HYDROCHEMISTRY OF THE ZEYA RESERVOIR IN HIGH-WATER YEARS

The results of studying the chemical composition of the waters of the Zeya reservoir in high-water years (2013, 2021) are presented. It is shown that a signifi cant infl ow of water into the reservoir during these years caused in its waters a uniform distribution of concentrations of dissolved substances in the water area and depth in the summer- autumn period and extremely uneven in winter. The maximum values of mineralization, concentrations of calcium, magnesium, bicarbonate and sulfate ions, ammonium nitrogen, organic substances and dissolved iron were established in winter in the estuarine areas of the Argi and Zey regions as a result of the infl uence of cryogenic processes and fl ooding of the marshes of the Upper Zey plain. In the dam and canyon parts of the reservoir in winter, there were no large diff erences in mineralization values (28,4–41,9 mg/dm3), low content of ammonium nitrogen (&lt; 0,03 mg N/dm3), increased values of water color (62–87°), concentrations of dissolved iron (0,35–0,74 mg/dm3) and organic matter (10,0–13,3 mg O/dm3). An assumption is made about the receipt of large amounts of dissolved substances in the Amur River in winter due to increased water consumption of the Zeyskaya HPP

Excessive use of chemical fertilizers in catchment areas raises the seasonal pH in natural freshwater lakes of the subtropical monsoon climate region

In recent years, the pH of some oligotrophic natural freshwater lakes in the subtropical monsoon climate region has generally reached an extremely high level of approximately 9.0 during the summer and autumn. It has not been proven that the explanation for why carbon assimilation in productive lakes exceeds carbon supply and causes a rise in pH also applies to oligotrophic freshwater lakes. Regardless, this may have been caused by changes in the solute composition of inflowing rivers as a result of changes in land use in catchment areas. Beimiao Reservoir in Baoshan City, Yunnan Province, where pH has increased significantly in summer and fall over the past few years, was chosen for this research in order to verify this hypothesis. This paper evaluates the status quo of water quality and nutrition in this reservoir. In addition, this paper analyzes the effects of water temperature, the metabolism of aquatic organisms, and river input on the horizontal and vertical spatial differences, diurnal variations, seasonal changes, and annual changes in the pH of the reservoir. It was discovered that one of the primary causes of the pH increase in natural freshwater lakes in the subtropical monsoon climate region during summer and autumn can be summarized as follows: A large amount of nitric acid and sulfuric acid are produced in the soil when chemical fertilizers are overused in runoff areas, particularly during intensive horticultural crop cultivation. Therefore, the subtropical monsoon climate region's soil loses calcium and magnesium ions, whose combined equivalent concentrations significantly exceed those of bicarbonate ions. The combined equivalent concentrations of calcium ions and magnesium ions in the inflowing rivers in summer and autumn are also significantly higher than those in the lake, resulting in the depletion of free carbon dioxide caused by calcium carbonate precipitation and an increase in pH. The conclusion of this research casts new light on the preservation and treatment of the ecological environment of lake water with similar issues.