Bicarbonate Water Research Articles

Review on the Impacts of the Samalas Eruption (1257 CE) to the Hydrogeological Conditions of Mataram, Lombok, Indonesia

This paper examines the local impacts of the 1257 CE Samalas eruption in the Mataram plain in relation to the hydrogeological conditions. Data from several previous studies in the Mataram plain is summarized and then reinterpreted. Data collected from new fieldwork is also presented. This review summarizes hydrogeological conditions into several categories, i.e. stratigraphy, aquifer formation, groundwater quality, and evolution. Two coring data were evaluated, which showed that Mataram plain has a relatively thick alluvial layer with a dominant material of sand mixed with pumice from the reworked deposit of the 1257 CE Samalas eruption. The sediment from this eruption formed a freshwater aquifer layer up to ~18 m deep. Using resistivity data, the aquifer layers in the studied area were characterized as unconfined aquifer, aquitard, and semi-unconfined aquifer. Seven water samples show that the groundwater in the studied area is in good condition, which indicates the bicarbonate water type. The results of the analysis show that the impact of the 1257 CE Samalas eruption on the hydrogeology of Mataram is considered a positive impact, i.e. forming an unconfined aquifer containing freshwater that is good for domestic uses.

Activation of periodate by CNT for selective catalytic oxidation: The overlooked significant role of residual metal species as catalytic sites

Carbon nanotubes (CNTs) catalyzed activation of peroxides has been extensively investigated, while the role of residual metal species in CNT in the catalysis is largely overlooked. In the study, calcination treatment of pristine CNT at high temperatures was employed as an approach to gain an insight into the role of residual metal species as catalytic sites in promoted catalytic activation of periodate (PI). Firstly, the calcination treatment at 500–1100 °C significantly promoted PI activation by calcined CNT. By constructing the quantitative structure–activity relationships (QSARs) between several surface and bulk properties of CNT (such as total surface oxygen content, surface carbonyl group, bulk defect and residual metal species) and PI activation performance, the residual metal species were identified as the catalytic sites. Moreover, the purification method of pristine CNT in the concentrated HNO3 was confirmed to be not efficient to remove these residual metals. The calcination treatment can tune the electronic structure of residual metal species, and promote their exposure and electron donation capacity for PI activation, thus significantly improving PI activation performance. Moreover, IO3• was identified as the dominant reactive species in CNT/PI system via a line of approaches including quenching experiments, PI decomposition in the presence/absence of organic pollutants, electrochemical testes, high selectivity in degradation of organic pollutants, QSARs of substituted phenols, and analysis of degradation products of 4-bromophenol. Furthermore, the CNT/PI system exhibited a wide pH application range of 3–11, high anti-interference to bicarbonate, chloride and phosphate in water. The study advances the understanding on the residual metal species in CNT and its overlooked catalytic role in PI activation, and also provides a high-performance oxidation process for wastewater purification.

Iron Toxicity in Plants: A Review

Iron (Fe) is an essential micronutrient for plant growth and development. However, increased absorption of iron leads to iron toxicity. This leads to damage to plant cell membranes, decreased growth, productivity, and thus general health. The presence of free iron in cells can lead to an imbalance Redox in cells Pro-oxidant state, thus generating oxidative stress. In plants, iron is involved in chlorophyll synthesis, and is therefore essential for maintaining the structure and function of chloroplasts. Micronutrients in the soil can limit plant growth, even if all other nutrients are available in sufficient quantities. Micronutrient deficiencies are widespread due to the nature of the soil, high pH, low organic matter, salt stress, and persistent drought. High levels of bicarbonate in irrigation water, as well as unbalanced use of fertilizers. Iron (Fe) toxicity is a widespread nutritional disorder. It grows in acidic, sulphurous soils, as well as low sandy soils (i.e. iron is easily reducible) that contain a high percentage of organic matter. Iron toxicity can be reduced by using rice that is tolerant to high levels of iron.

Characterization of Geochemical and Isotopic Profiles in the Southern Zone Geothermal Systems of Mount Seulawah Agam, Aceh Province, Indonesia

The Seulawah Agam geothermal area exhibits significant potential as a source of energy for power generation, with an estimated capacity of 130 MW. Geological and geochemical investigations indicate that the Seulawah Agam geothermal system is part of the extensive Sumatra Fault. Analysis of the geochemical composition of geothermal water at the South Zone manifestation location of Mount Seulawah Agam, Aceh Province-Indonesia, involves examining cation (K+, Na+, Ca2+, and Mg2+), anion (Cl-, HCO3-, and SO42-), and isotope (δD and δ18O) contents. This data aids in estimating reservoir temperatures using geothermometer equations. Surface characteristics of the South Zone manifestation reveal neutral to alkaline pH values (6.02 to 8.68), relative temperatures (29.97 to 42.57 ºC), conductivity (49.8 to 100.7 mV), and TDS (Total Dissolved Solids) ranging from 352.6 to 497.0 mg/L. The dominant water composition is sodium–calcium–bicarbonate (Ca–Na–HCO3), indicating a bicarbonate water type. Average temperature depths in the South Zone manifestation of Mount Seulawah Agam are estimated as follows: Alue Ie Seu’um around 288.84 ± 2.19 ºC, Alue Ie Masam around 304.17 ± 20.9 ºC, Alue PU around 290.02 ± 6.85ºC, and Alue Teungku around 265±11.39 ºC. Isotope data (δD and δ18O) suggest meteoric water as the source for this manifestation. Fluid geochemical analysis indicates the potential for utilizing the geothermal manifestations of the South Zone of Mount Seulawah Agam for geothermal development or the construction of a geothermal power plant, given its high enthalpy system with an average temperature exceeding 225 ºC. Further research, including data drilling, is essential to gather precise subsurface data. Additionally, the Aceh Provincial Government should formulate policies to identify strategic areas for geothermal development, leveraging the existing exploitable potential.

THE CHEMICAL ORIGIN AND GEOTHERMOMETERY OF HOT SPRINGS WATERS IN THE REGION OF KHENCHELA, ALGERIA

Our study is carried out on the trio of thermomineral waters in the region of Khenchela - Hammam Salhin, Hammam Knif, and Hammam Djaarir - Northeast of Algeria. The purpose of this study is to determine the physicochemical and geothermal origin of the thermal spring (temperature, pH, and electrical conductivity). The temperatures of the thermal water samples which were being studied varied from 38 to 72°C; therefore, this variation has a direct relation to the climatic conditions and/or the combination of the water which is derived from various sources in the formation of the thermal spring. Additionally, the pH value of the spring under study is of a neutral to slightly alkaline quality, while its electric conductivities are high, ranging from 3059 μS/Cm to 5007 μS/Cm. The Piper diagrams presented the domination of sodium chloride (Na-Cl) and sodium sulfate (Na-SO4) facies as two types of water in the hydrochemical facies. These facies indicate the mineral composition of the thermal waters, a product from the reservoir by way of geological formations in the subsurface. This is a plausible reason from the chemical changes observed in the fluids and can well be associated with the high influence of water-rock interaction, that is, the formation of sodium bicarbonate water to sodium-chlorinated water formation, where it is linked with the effects of dissolution and salinity in the formation of saliva found in regions with semi-arid climatic conditions. Evaporation would play a major role in increasing the sodium content, while the IIRG plots closer to the industry "α" standard than the other plots. These are the characteristic features of an evaporation-based system. The crucial parameter C serves as a strong indicator of circulation in carbonate reservoirs subject to evaporation.

Исследование химического состава воды подземного источника, расположенного на пойменном участке реки Малка в нижнем течении

The analysis of an undergroundsourcewaterchemicalcomposition located inthe floodplain oftheMalka River,the largestriver flowing through the territory of the Kabardino-Balkarian Republic, is presented. Data on the quantitativecontent of the groundwater ion-saltcomposition components serve as indicators to identify background concentrations of pollutants in river waters. The observation results of the intra-annual dynamics of flow, temperature, transparency, pH, mineralization, hardness, permanent oxidability, concentrations of carbonates, bicarbonates, chlorides, sulfates, nitrites, nitrates, and total iron are presented. The qualitative trace element composition has been determined. The results of sanitary and microbiological analysis are presented. The theoretical analysis allows us to conclude that the chemical composition of the water under study follows general patterns. The constancy of the underground source waters temperature indicates the deep occurrence of aquifers. The chemical composition of water is determined by the composition of minerals and rocks, which it comes into contact with, remains almost constant throughout the year and, to a small extent, depends on climatic conditions on the surface. Data on the concentration of components of the ion-salt composition and microflora characterizing the water quality of an underground source were obtained. The water of an underground source refers to neutral, fresh, medium hardness, bicarbonate waters that are not contaminated with pathogenic microflora.

Biogas Upgrading by Wild Alkaliphilic Microalgae and the Application Potential of Their Biomass in the Carbon Capture and Utilization Technology

Although biogas is a renewable energy source alternative to natural gas, it contains approximately 40 vol% CO2 and, hence, a low calorific value. The sequestration of CO2 from biogas is, therefore, essential before its widespread use. As CO2 can be easily solubilized as carbonate and bicarbonate in alkaline water, in this study, we isolated and characterized alkaliphilic wild microalgae that grow under high-level CO2 conditions and evaluated their application potential in CO2-removal from biogas. For this purpose, freshwater samples were enriched with 10 vol% CO2 and an alkaline culture medium (pH 9.0), wherein almost free CO2 was converted to carbonate and bicarbonate to yield alkaliphilic and high-level CO2-tolerant microalgae. Ten microalgal strains of Micractinium, Chlorella, Scenedesmus/Tetradesmus, or Desmodesmus spp. were isolated, some of which demonstrated good growth even under conditions of >pH 10 and >30 vol% CO2. All algal strains grew well through fixing biogas-derived CO2 in a vial-scale biogas upgrading experiment, which reduced the CO2 level in biogas to an undetectable level. These strains yielded antioxidant carotenoids, including lutein, astaxanthin, zeaxanthin, and β-carotene, particularly rich in lutein (up to 7.3 mg/g dry cells). In addition, these strains contained essential amino acids, accounting for 42.9 mol% of the total amino acids on average, and they were rich in unsaturated fatty acids (comprising 62.2 wt% of total fatty acids). The present study identified strains that can contribute to biogas upgrading technology, and the present findings suggest that their biomass can serve as useful raw material across the food, nutraceutical, and feed industries.

Geophysical, hydrogeological and laboratory assessment of groundwater quality and its health implication in some urban communities in cross river state

The electrical resistivity technique which involved the Schlumberger depth sounding method, electrical resistivity tomography and geochemical analyses of water samples collected from boreholes were used to investigate the quality of groundwater in some urban communities in Cross River State, also the health implication of the said groundwater was also investigated. Forty nine electrical resistivity data were collected, modeled, and interpreted after calibration with lithologic logs. Ten electrical resistivity tomography data was were also collected, modeled and interpreted. Forty nine borehole water samples were collected and analyzed to determine anion, cation concentrations and some physical and chemical parameters, such as water colour, temperature, total dissolved solids, and electrical conductivity. The results show that the lithostratigraphy of the study area is composed of sands, sandstones (fractured, consolidated and loosed), siltstones, shales (compacted and fractured) of the Asu River Group, Eze-Aku Formation which comprises the aquifer units, and the Nkporo Shale Formation. The aquifer conduits are known to be rich in silicate minerals, and the groundwater samples in some locations show a significant amount of Ca2+, Mg2+, and Na+. These cations balanced the consumption of H+ during the hydrolytic alteration of silicate minerals. The geochemical analysis of groundwater samples revealed dominant calcium–magnesium–carbonate– bicarbonate water faces. The groundwater quality was observed to be influenced by the interaction of some geologic processes but was classified to be good to excellent, indicating its suitability for domestic and irrigation purposes.

Groundwater dilution and flow conditions in sulfuric acid caves: the case study of Frasassi (Italy)

This study analyzes the dilution process of the sulfidic groundwater in the Frasassi caves due to the recharge of O2-rich freshwater and its influence on the sulfuric acid speleogenesis and morphogenesis. The drainage pattern and the seasonal changes of the chemo-physical characteristics of the groundwater through a year-long monitoring and the measurements of the groundwater levels are presented. The inflow of water infiltrating from the karst surface influenced the sulfidic groundwater parameters, reflecting the seasonal meteoric cycle. On the contrary, the Sentino River, which represents the local base level, directly influenced the groundwater only in the most external part of the cave. The water level measurements evidenced a low hydraulic gradient (~3‰), due to the high karstification, and also some differences in the permeability depending on the drainage direction. Most cave pools are isolated on the surface and connected to each other through a network of submerged passages. In the present conditions, a surface layer of bicarbonate water forms above the sulfidic water in a large part of the cave, where it impedes subaerial corrosion by released acidic gases. Conversely, the distribution of residual gypsum deposits and corrosional wall features in the upper old cave levels demonstrate that large interfaces between sulfidic water and cave atmosphere existed during some periods of the cave history. Here, the release of acidic gases (CO2 and H2S) and the production of H2SO4 from H2S oxidation caused the widespread subaerial corrosion which significantly contributed to the morphogenesis. The comparison between these residual morphologies and the active processes shows that morphogenesis in the cave has evolved through time, influenced by hydrodynamic conditions, in turn depending on the general morphological and hydrogeological setting of the whole karst area.

Reagentless reduction of hydrogen carbonate-calcium hardness of water: equilibrium states and kinetics

The equilibrium states and kinetics of changes in the concentrations of carbonate system components in water with different calcium hardness are analyzed and the possibility of reducing this indicator by an environmentally friendly method, aeration, is evaluated. Changes in the concentrations of dissolved carbon dioxide, calcium ions, hydrogen ions (pH), bicarbonate and carbonate ions in water depending on the partial pressure of carbon dioxide in soil and atmospheric air and the kinetics of reducing the bicarbonate-calcium hardness of water during its natural and forced aeration were traced. It is shown that water purification by a stream of atmospheric air microbubbles with an average radius of 50 m and a flow rate of 10 l/min can reduce the hydrogen carbonate-calcium hardness from 8 mg-eq/l to 1 mg-eq/l in 100 liters of water in 20 minutes. In the paradigm of "green chemistry", this method is more rational, environmentally friendly, and economical than ion exchange or reverse osmosis, which are currently practiced to reduce hardness in decentralized water supply systems.

Water quality, geochemistry and human health risk of groundwater in the Vyeboom region, Limpopo province, South Africa

This study focuses on the evaluation of trace metals as well as microbial contamination of groundwater. Groundwater samples were collected from 17 boreholes. The microbial quality was tested using membrane filtration method. Higher levels of contamination for both E. coli and total coliform was recorded in the wet season. Majority of the boreholes had nitrate levels above the regulatory guideline value of the World health Organisation and the South African National Standards. The water type was established by Piper plot which showed the predominance of a magnesium bicarbonate water type, with alkaline earth metals dominating the alkali metals, as well as the weaker acids (bicarbonates) dominating the stronger ones (Sulphates and chlorides). Most of the trace metals detected were in compliance with the regulatory standard except for aluminium (0.41–0.88 mg/L). The hazard quotient and Hazard indice exceeded 1 mostly for children in both season which implies a possible non-carcinogenic health risk is associated with the continuous consumption of the water resource. The estimations of carcinogenic risk (CRing) for Cr and Pb exceeded the carcinogenic indices of 10−6 and 10−4 which could pose adverse effects on human health for both children and adults. Therefore, it is recommended that measures should be implemented to reduce the risk.

Impact of complementary irrigation on soil properties in the Argentine Pampas

The growing application of complementary irrigation in extensive agricultural systems in the Pampas region (Argentina) has increased the frequency of disturbed soil cases. Irrigation management requires appropriate indicators for decision-making in order to avoid disturbance in soil quality. Among these indicators, the use of the sodium adsorption ratio adjusted by the dilution factor (SARdf), which considers the contributions of irrigation water and rainfall during the period projected, could be a sensitive tool. Based on studies conducted under extensive conditions of agricultural production, the objectives of this work were to (i) quantify the changes in the soil chemical and physical properties caused by the use of complementary irrigation with sodium bicarbonate water; (ii) establish relationships between the changes in the chemical and physical properties of the soil; (iii) validate the use of SARdf as a tool to help manage complementary irrigation; and (iv) identify the threshold values to be considered when monitoring and analyzing the evolution of soil properties in areas under complementary irrigation. Twenty-three sites under dryland and irrigated conditions were evaluated. With increasing SARdf, an increase was also recorded in surface bulk density (r = 0.59), subsurface bulk density (r = 0.50), electrical conductivity (r = 0.30; 0.41), pH (r = 0.56; 0.70) and exchangeable sodium ratio (ESR) (r = 0.45; 0.77), measured in the layers up to 0.10 m and up to 0.20 m in depth. The ESR was evaluated as a sensitive indicator of the effects of irrigation on the physical and chemical properties of soils. In the predominant Typic Argiudoll conditions of the Pampas region, it is advisable to avoid the complementary application of water with a SAR dilution factor greater than 3.0. This threshold value was associated with a > 60% reduction in basic infiltration. In climate change scenarios, the use of SARdf can help plan the proper management of complementary irrigation.

Facile and green synthesis, crystal structure, antibacterial activity, Hirshfeld surface analysis, and computational investigation of a novel lithium(I) complex: Comparisons of theoretical and experimental analyses

A novel monovalent lithium complex, [Li(C6H4NO3)(H2O)2] (1), was prepared via a simple one-pot green reaction of 2-hydroxypyridine-3-carboxylic acid (2-hpca) with lithium carbonate and aminoguanidine (Amgu) bicarbonate in water. Complex 1 was investigated using elemental, ultraviolet–visible, Fourier transform infrared (FT-IR), thermal, and single-crystal X-ray diffraction (SC-XRD) measurements. We found that 1 crystallized in the monoclinic C2/m space group with a = 12.800(2) Å, b = 6.6657(13) Å, and c = 9.4687(19) Å. The Li ion exhibited four coordinates with a distorted square planar geometry. That is, the ion was surrounded by four oxygen atoms, of which two were derived from two water molecules, one was from the carboxylate group, and one was from the keto group of the 2-oxo-1,2-dihydropyridine-3-carboxylate ligand. Simultaneous thermogravimetry–differential thermal analysis of 1 exhibited dehydration followed by continuous low-temperature (∼400 °C) decomposition to produce lithium oxide as the end product in an air atmosphere. Furthermore, density functional theory (DFT) analysis was conducted to compare the theoretical and experimental data collected via SC-XRD. In addition, DFT was used to analyze the frontier molecular orbital energy levels and energy gaps. Moreover, we conducted Hirshfeld surface studies with respect to 1 to differentiate between the intermolecular hydrogen bond contacts. Energy frameworks for 1 were produced by analyzing the energy interactions between intermolecular hydrogen bonds to investigate the prevailing interactions involved in molecular packing. The in silico results showed that 1 has high potential for the development of antimicrobial drugs. Molecular docking studies were also conducted to determine the binding energy of 1 with Staphylococcus aureus (5CZZ) and Escherichia coli (3T88). The results were consistent with the experimental data obtained from the antibacterial activity of 1 with respect to Staphylococcus aureus and Escherichia coli.

Conceptual model of groundwater flow in a volcanic-sedimentary aquifer system of the Andean region of Chimborazo, Ecuador

The Chimborazo volcano is located in Ecuador's northern Andes and is one of the world's tallest mountains. The central valley of Riobamba's morphology, structure, and groundwater flow networks are all influenced by the evolution of this stratovolcano. Both the urban and rural populations in this area rely on groundwater extracted from volcano-sedimentary aquifers. This study presents a conceptual model of the groundwater flow system in the lower Chambo River basin (LCRB) based on the interpretation of geological, hydrogeological, hydrochemical, and stable isotope (δ18O and δ2H) data from 23 wells, 10 springs, two sources of surface water, and rainwater. The Tertiary-Quaternary volcanic-sedimentary infill of the Inter-Andean Valley, that overlies the Jurassic-Cretaceous metamorphic bedrock of the Eastern and Western cordilleras, gave rise to three multilayer aquifers (Llo-Guano, Riobamba, and Yaruques). In these aquifers, groundwater flows from the recharge of Chimborazo glaciers to deep circulation zones of low-elevation lands in Riobamba. In this pathway, groundwater evolves from acidic - low temperature - low electric conductivity bicarbonate waters to alkaline - high temperature - high electric conductivity sulfate waters discharged in the Chambo River. The stable isotope data confirmed the hypothesis of different types of water changing and interacting in the flow direction, demonstrating a dynamic hydrogeological system that evolves from the recharge area in Chimborazo, Igualata, and Altar volcanoes to the discharge area in the Chambo River.

HPLC with Post-Column Derivatization with Alizarin for Determination of OATD-02, an Anticancer Arginase Inhibitor in Clinical Development

The aim of this study was to develop an analytical method for selective determination of OATD-02 by high-performance liquid chromatography (HPLC) with post-column derivatization and fluorescence detection (FLD). OATD-02, a new boronic acid derivative, is a highly potent anticancer arginase inhibitor in clinical development. Chromatographic analysis of OATD-02 poses problems because this molecule has weak ultraviolet absorption. The derivatization reaction was based on the reaction between boronic acid from OATD-02 and alizarin solution. The optimized mobile phase consisted of a mixture of sodium bicarbonate in water and acetonitrile at a flow rate of 0.50 mL/min. Alizarin solution in methanol was delivered at a flow rate of 0.50 mL/min. The fluorescent complexes were detected by a fluorescence detector (excitation and emission wavelengths at 470 and 580 nm, respectively). The present method demonstrated proper values for selectivity, linearity, recovery (>99%), precision (RSD: 0.6%), sensitivity (LOD: 20 µg/mL and LOQ: 50 µg/mL), stability of solutions, and robustness.

Experimental precipitation of cryogenic carbonate

Cryogenic cave carbonates (CCC) represent a specific type of speleothem precipitating from freezing water in caves. Over the past decade, considerable progress has been made concerning cryogenic calcite petrography, crystallography and geochemistry. Uncertainties remain, however, as the cave waters from which ancient cryogenic calcites form are not preserved. The present study provides an experimental approach to re-calculate the isotopic composition of the precipitating solution using CCC data. Calcium-rich bicarbonate water prepared by bubbling CO2 gas with a very low δ13C value (∼ −35 ‰) into the water was cooled under controlled laboratory conditions to account for the water chemistry changes during freezing. The experiments yielded cryogenic calcite and vaterite precipitating at temperatures of +1, +0, −0.5, −0.7, −1 and − 2 °C, with complete freezing occurring at −0.7, −1 and − 2 °C and partial freezing at −0.5 °C. The δ18Owater and δ13CDIC values, pH, electrical conductivity and alkalinity were recorded before and after the experiments. Our work documents an increase in pH, suggesting CO2 degassing eventually reaches supersaturation with calcite, leading to CaCO3 precipitation. Calcite precipitation rates are lower at the longer experiment (> 45 days). This is further confirmed by the decreasing calcite saturation index (SIcc) with time. Carbon isotope analyses of the water and carbonates revealed kinetic effects during rapid freezing. A large increase in Δ13CDIC values of the water (up to about 30 ‰) was found between the start and end of the experiments. Reasons may include CO2 degassing with increasing time leading to a markedly 13C-enriched solution. Based on our experimental data, the cryogenic crystal morphotypes are related to the precipitation sequence. Sharp-edged rhombohedra (calcite) precipitate first. Subsequently, spherulitic (vaterite) morphotypes precipitate from almost completely frozen water characterised by a high SIcc. This first experimental work dealing with cryogenic carbonate precipitates and their stable isotope composition sheds light on the origin of these peculiar speleothems and provides constraints to interpret morphologies and isotopic compositions of ancient CCCs.

Hydrogeochemistryof groundwater in Es-Sbikhat El-Mahmel basin, Khenchela (NE Algeria)

Es-Sbikhat El-Mahmel basin, located at the southeastern piedmont of Aures massif (Northeastern Algeria), is characterized by a semi arid condition . The sampling process was realized within 39 boreholes and wells during May 2015. Results of analysis data projected on the PCA (Principal Componet Analysis) plan which express 52.70% of variance has shown a chemical facies evolution from calcium bicarbonate water into calcium chloride water, going through a transition facies marked by calcium-sulfate to magnesium-sulfate water.Thermodynamic analysis corroborated that water rock interaction is the main process that control mineralization (dissolution precipitation, cationic exchange and anthropogenic pollution).

Chemical Characteristics and Controlling Factorsof Groundwater in Chahannur Basin

This paper studies the spatial distribution characteristics and controlling factors of groundwater chemistry in the Chahannur Basin. One hundred and seventy shallow groundwater samples (50 m shallow) are collected, and seven ions, pH, TDS, TH, iron, manganese, COD, barium and other indicators, are detected. Piper triplex graph, Gibbs model, ion ratio, analysis of variance and Kriging interpolation are used to carry out the research. The results show that bicarbonate water is the main water chemical type in the Chahannur Basin, in which bicarbonate water accounts for 65.23%, chloride water accounts for 15.15% and sulfate water accounts for 19.62%. Bicarbonate water is mainly distributed in the mountainous areas in the north and south of the basin, and the main controlling factor is rock weathering. Sulfate-type water is mainly distributed in the lower reaches of the northern mountains of the basin, and the main controlling factors are rock weathering and evaporation concentration. The chloride water is mainly distributed in the Chahannur Lake area and the shallow groundwater buried area in the central region of the basin. The main controlling factors are evaporation concentration and human influence. Na+ is mainly derived from atmospheric precipitation and rock salt leaching, Ca2+ and Mg2+ are mainly derived from carbonate minerals leaching, and silicate minerals leaching is less. The pH of groundwater in the basin ranges from 6.3 to 9.18, with an average value of 7.50. The TDS in the basin ranges from 227 to 22,700 mg/L, with an average of 1661 mg/L. Iron in the catchment ranges from 0.01 to 15.343 mg/L, with a mean of 0.837 mg/L. The manganese content in the basin ranges from 0.005 to 3.802 mg/L, with an average value of 0.254 mg/L. COD in the basin ranges from 0.71–32.72 mg/L, with an average value of 3.49 mg/L. Barium in the basin ranges from 0.005 to 0.312 mg/L, with an average of 0.075 mg/L. The research results provide basic scientific data support for groundwater hydrochemistry research in the Chahannur Basin and show that the types of water chemistry in the study area are complex and diverse, and although the distribution is still controlled by terrain and geological conditions, the area affected by human activities accounts for a high proportion, so attention should be paid to the impact of human activities on groundwater in this area.

ANÁLISIS HIDROGEOQUÍMICO DE LA CALIDAD DE AGUAS SUPERFICIALES EN UNA ZONA MINERA EN EL FLANCO OESTE DE LA CORDILLERA OCCIDENTAL DE LOS ANDES

This study used the hydrogeochemical properties of surface waters surrounding a mining project in Peru to compare them with the environmental quality standards established in Supreme Decree 004-2017-MINAM, focusing on category 3 for vegetable irrigation and animal drinking. Physical-chemical, inorganic, microbiological and parasitic parameters were evaluated in lagoons and springs. The results determined the presence of slightly alkaline deposits with a pH of 9.59 and slightly acidic deposits with a pH of 5.33, as well as deposits with high content of iron, manganese, and zinc. To ensure the reliability of the chemical analysis, an ionic balance of the main dissolved cations and anions was performed. The Piper diagram determined the predominant calcic sulfate waters, as well as the presence of a calcic bicarbonate water deposit. On the other hand, the Stiff diagram determined sulfate (SO42-) as the predominant ion. This study concludes that the different stations comply with the environmental quality standards, although deposits with high levels of iron, manganese, and zinc were found in surface waters. Different treatments were determined to control pH levels and to decrease the amount of such ions present.

Bicarbonate waters in hydrogeological complexes of the hypergenesis zone of the Southern Cis-Urals

The article deals with the formation and distribution of bicarbonate groundwater in the hydrogeological complexes of the hypergenesis zone of the Southern Cis-Urals. Particular attention is paid to the issues of the distribution of bicarbonate groundwater in the hydrogeological section, which are of the greatest practical importance for the purposes of drinking water supply in the region. On the basis of long-term complex field and experimental studies, it has been established that the formation of the chemical composition and distribution of these waters in hydrogeological complexes is subject to the laws of vertical hydrogeodynamic and gas-hydrochemical zonality. The influence of technogenesis on the qualitative composition of these waters is noted.