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The Arctic river basins, among the most sensitive regions to climate warming, are experiencing rapid temperature rise and permafrost thawing that profoundly affect their hydrological and hydrochemical systems. However, our understanding of chemical export from Arctic basins to oceans remains limited due to scarce data, particularly in permafrost-dominated regions. This study examines the spatiotemporal variations and seasonal dynamics of major ions (Na+, K+, Mg2+, Ca2+, Cl−, SO42−) and dissolved organic carbon (DOC) concentrations across three river basins with varying permafrost extents: the Severnaya Dvina (2006–2008, 2012–2014), the Pechora (2016–2019) and the Taz Rivers (2016–2020). All the data were sourced from published Chemical Geological researches and were taken from Mendeley and PANGAEA datasets. Our results showed that DOC concentrations ranged from 1.75 to 26.40 mg/L, with the Severnaya Dvina River exhibiting the highest levels of DOC concentrations, alongside significantly elevated ion concentrations compared to the other two basins. A positive correlation was observed between DOC concentrations and river discharge, with peaks during the spring flood and summer baseflow due to leaching processes. The Severnaya Dvina and Pechora Rivers exhibited the highest DOC values during the spring flood, reaching 26.40 mg/L and 8.07 mg/L, respectively. In contrast, the Taz River had the highest runoff during the spring flood season, but the DOC concentration reached its highest value of 11.69 mg/L in the summer. Specifically, a 1% increase in river discharge corresponded to a 1.25% rise in DOC concentrations in the Severnaya Dvina River and a 1.04% increase in the Pechora River, while there was no significant correlation between runoff and DOC concentrations in the Taz River. Major ion concentrations demonstrated a negative correlation with river discharge, remaining relatively high during winter low-flow period. A robust power-law relationship between river discharge and concentration of DOC and major ions was observed, with distinct variations across the three river basins depending on permafrost extent. The Pechora and Taz Rivers, characterized by extensive permafrost, exhibited increasing trends in river discharge and DOC concentrations, accompanied by decreasing major ion concentrations, whereas the non-permafrost-dominated Severnaya Dvina River basin showed the opposite pattern. The Taz River, with the most extensive permafrost, also displayed a delayed DOC peak and more complex seasonal ion concentration patterns. These findings highlight the importance of varying permafrost extents and their implications for water quality and environmental protection in these vulnerable regions. [ABSTRACT FROM AUTHOR]

Abstract Clean river water is an essential and life-sustaining asset for all living organisms. The upper Ganga and Yamuna river system has shown signs of rejuvenation and tremendous improvement in the water quality following the nationwide lockdown due to the coronavirus pandemic. All the industrial and commercial activity was shut down, and there was negligible wastewater discharge from the industries. This article addresses the water quality assessment from the study area, which is based on the original data of physical parameters, major and trace elements, and stable isotopes (hydrogen and oxygen) systematics during the nationwide lockdown. The impact of the lockdown could be seen in terms of an increase in dissolved oxygen (DO). Water samples were collected from the Upper Ganga and Yamuna river basins (Alaknanda, Bhagirathi, and Tons rivers) during an eight-week lockdown in Uttarakhand, India. We discussed the signs of rejuvenation of riverine based on physical parameters, major ions, trace elements, isotopic ratios, and water pollution index (WPI). Results reveal that the water quality of the entire upper basins of the Ganga has significantly improved by 93%, reflecting the signs of self-rejuvenation of the rivers. Multivariate analysis suggests a negative factor loading for an anthropogenic element ( $${NO}_{3}^{-}$$ NO 3 - ), implying that they contribute little to the river water during the lockdown. Further, bicarbonate ( $${HCO}_{3}^{-}$$ HCO 3 - ) is a dominant element in both river basins. The geochemical facies are mainly characterized by the ( $${{Ca}^{2+} :{Mg}^{2+} : HCO}_{3}^{-}$$ Ca 2 + : Mg 2 + : H C O 3 - ) type of water, suggesting that silicate rock weathering dominates with little influence from carbonate weathering in the area. The positive factor loadings of some cations, like $${HCO}_{3}^{-}$$ HCO 3 - , $${Ca}^{2+}$$ Ca 2 + , and $${Mg}^{2+}$$ Mg 2 + reflect their strong association with the source of origin in the lockdown phases. Stable isotopic reveals that the glaciated region contributed the most to the river basin, as evidenced by the low d-excess in riverine water compared to anthropogenic contributions. Rivers can self-rejuvenate if issues of human influence and anthropogenic activities are adequately resolved and underline our responsibility for purifying the ecosystem. We observed that this improvement in the river water quality will take a shorter time, and quality will deteriorate again when commercial and industrial activity resumes.

Clean river water is an essential and life-sustaining asset for all living organisms. The upper Ganga and Yamuna river system has shown signs of rejuvenation and tremendous improvement in the water quality following the nationwide lockdown due to the coronavirus pandemic. All the industrial and commercial activity was shut down, and there was negligible wastewater discharge from the industries. This article addresses the water quality assessment from the study area, which is based on the original data of physical parameters, major and trace elements, and stable isotopes (hydrogen and oxygen) systematics during the nationwide lockdown. The impact of the lockdown could be seen in terms of an increase in dissolved oxygen (DO). Water samples were collected from the Upper Ganga and Yamuna river basins (Alaknanda, Bhagirathi, and Tons rivers) during an eight-week lockdown in Uttarakhand, India. We discussed the signs of rejuvenation of riverine based on physical parameters, major ions, trace elements, isotopic ratios, and water pollution index (WPI). Results reveal that the water quality of the entire upper basins of the Ganga has significantly improved by 93%, reflecting the signs of self-rejuvenation of the rivers. Multivariate analysis suggests a negative factor loading for an anthropogenic element ( NO 3 - ), implying that they contribute little to the river water during the lockdown. Further, bicarbonate ( HCO 3 - ) is a dominant element in both river basins. The geochemical facies are mainly characterized by the ( Ca 2 + : Mg 2 + : H C O 3 - ) type of water, suggesting that silicate rock weathering dominates with little influence from carbonate weathering in the area. The positive factor loadings of some cations, like HCO 3 - , Ca 2 + , and Mg 2 + reflect their strong association with the source of origin in the lockdown phases. Stable isotopic reveals that the glaciated region contributed the most to the river basin, as evidenced by the low d-excess in riverine water compared to anthropogenic contributions. Rivers can self-rejuvenate if issues of human influence and anthropogenic activities are adequately resolved and underline our responsibility for purifying the ecosystem. We observed that this improvement in the river water quality will take a shorter time, and quality will deteriorate again when commercial and industrial activity resumes. [ABSTRACT FROM AUTHOR]

This study investigates the potential health risks associated with ion concentrations in fountains used for drinking water in the Antalya/Konyaaltı tourism center region. A total of 32 fountain samples commonly used during the summer were analyzed to determine the anion and cation concentrations using ion chromatography equipped with a conductivity detector. The results showed high accuracy and reliability, with R2 values ranging between 0.998 and 0.999 and recovery values between 97% and 110% at low and high concentrations. The method detection limit and method quantification limit were determined as 0.004 and 0.276, respectively, whereas the pH values ranged from 6.71 to 7.69. When examining the average fluoride and nitrate levels in different age groups, the nitrate daily acceptable intake (total hardness index) values were found to be 0.175, 0.091, and 0.076 µg kg−1 body weight per day for children, adolescents, and adults, respectively. Overall, the study suggests that children have the highest exposure levels due to their lower body weight, and exposure levels decrease with increasing age. [ABSTRACT FROM AUTHOR]

The concentration of major ions ( , Cl–, , Ca2+, Mg2+, Na+, and K+) in the water of tributaries of Lake Teletskoe (Northeastern Altai) was studied in 2016–2020. Seasonal variations were found in the ion composition of the water of lake tributaries and a relationship between this composition and the biogeochemical conditions in their drainage basins was established. The waters of eastern and western tributaries, which drain shores with different geological and landscape structure, differ in both the concentrations and proportions of the major ions. It is shown that most of the examined tributaries belong to the same hydrogeochemical facies and carry water of bicarbonate-magnesium-calcium type. Characteristics of ion runoff of three lake tributaries were calculated; chemical denudation in their drainage basins was evaluated. [ABSTRACT FROM AUTHOR]

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Study region: A typical estuarine delta of Gan−Xiu River within Poyang Lake watershed, situated in the north of Jiangxi Province, China Study focus: Although groundwater is considered as a crucial water resource for social development and public health, it presents significant challenges in preventing the deterioration of groundwater quality in the seasonal floodplain regions. Hence, this study focuses on the spatiotemporal variations of ionic concentrations of shallow groundwater in an estuarine delta of Gan-Xiu River in Poyang Lake watershed, which is greatly complicated by complex hydrological regimes and intensive anthropogenic activities such as cropland fertilizer. The potential factors controlling the ionic concentrations were identified using self-organizing map clustering and Piper diagram approaches. Moreover, the overall water quality of shallow groundwater was assessed according to the ionic compositions. New hydrological insights for the region: (1) Shallow groundwater chemistry was influenced by weathering silicate and carbonate from ionic and Gibbs plots, which is highly associated with the distribution of the carbonate rock fissure-karst aquifer in the study region. (2) The contribution of groundwater to river water varied from 53.2 % to 71.5 % via isotopic analysis, suggesting that groundwater dominate the component of river water. (3) Most samples from cluster types are suitable for drinking and irrigation use except for sites from Cluster 6, which were characterized by the higher concentrations of Cl−, NO3− and SO42−.

The Red River originating from Yunnan province, China is the second largest river in Vietnam in terms of length and discharge. Combination of water chemistry monitoring data of 4 years (2018–2022) from different sub-basins of the Red River (the Da, Lo, Thao, Tra Ly, and Day) with historical datasets indicates a decline in pH from 8.1 in 2000 to 7.7 in 2021, greater CO2 concentrations and a shift from waters naturally dominated by carbonate weathering to waters dominated by evaporite weathering. Such changes were most apparent in the delta area where heavy human activities have increased influxes of most dissolved chemicals, except SiO2. Evaporite weathering is particularly enhanced by mining and deforestation occurring in upstream regions of both China and Vietnam. Pyrite oxidation, alongside silicate weathering, is enhanced along the Red River Fault Zone but reduced in tributaries with a higher proportion of hydropower reservoirs. Longer water residence times in these large reservoirs (total volume > 2.7x1010 m3) located in the Da and Lo sub-basins have also increased primary productivity, leading to higher evasion/uptake of CO2 and SiO2, lower total dissolved solids (TDS), and higher pH. The total physical and chemical denudation rates of upstream mountain tributaries ranged between 0.107 ± 0.108 and 0.139 ± 0.137 mm yr−1, mainly due to reservoir implementation and instream aquatic biogeochemistry changes. Our findings demonstrate that anthropogenic activities are profound factors impacting the water chemistry of the Red River system.

Relevance. Foothill (foredeep, pericratonic) deflections play a significant role generation and localization of hydrocarbon accumulations and are promising objects of oil and gas exploration. Numerous studies of such structures are focused mainly on the geological structure, formation and prospects of oil and gas potential of these territories. Issues related to the geochemistry of natural waters are either not covered at all, or are presented in an extremely limited form. Studying the chemical composition of the natural waters of the Predverkhoyansk foredeep at the modern analytical level will make it possible to assess the hydrogeochemical background and emphasize the peculiarities of the behavior of the main components of the aquatic environment in conditions of a sharp change in the tectonic situation. Aim. To study and identify the hydrogeochemical features of the composition of natural waters in the area of the eastern framing of the Siberian platform in the region of its junction with the scaly-thrust dislocations of the Verkhoyano-Kolyma folded zone. Methods. Measurements of rapidly changing parameters of natural waters (pH, Eh, temperature) were carried out directly at the sampling site with a portable HQ-40D analyzer from Hach Lange (USA). The analysis of the chemical composition of waters was carried out in the Problematic Research Laboratory of Hydrogeochemistry of Tomsk Polytechnic University using ion chromatography methods on a two-channel reagentless ionochromatographic complex ICS-5000 with conductometric detection manufactured by Dionex-Thegmo Scientific (USA). The content of CO32– and HCO3–anions in the studied waters was determined by the traditional titrimetry method for these indicators. The Si concentration was determined by inductively coupled plasma mass spectrometry on a NeXION 300D device, Perkin Elmer (USA). Results. The paper presents the data on the chemical composition of the natural waters of the Tompo, Lyapiske, Sobolokh-Mayan (Sobopol) river basins in the inner part of the Predverkhoyansk foredeep in front of the cutting edge of the advanced thrust of the western slope of the Verkhoyansk anticlinorium. The patterns of the distribution of basic ions are shown, common features and differences between the studied sites are revealed.

The main findings of a hydrochemical investigation conducted within a typical Dinaric karst catchment located in Southern Croatia are outlined. The studied aquifer is drained by the Jadro and Žrnovnica springs, which are important for the regional and local water supplies, respectively. Presumably, there is intercatchment groundwater flow coming from the neighbouring Cetina River catchment. Various factors governing aquifer hydrochemistry and their interplay with emerging organic contaminants (EOCs) that were detected at different water resources in ng/L concentrations was assessed. A total of 26 sampling campaigns (October 2019 - October 2022) were conducted at two springs, in a river and at a deep borehole, all representative of this complex hydrogeological system. Assessment of major ion constituents and saturation indices calculated with PHREEQC revealed the sampled water resources are of a Ca-HCO3 type due to the predominant weathering of the carbonate mineral calcite. Sharp spikes observed in chemographs indicated a highly karstified system with an effective conduit network allowing rapid spring responses to precipitation events. Water resources are of good chemical status, as affirmed by anthropogenic contamination indicators, with nitrates, chlorides and sulphates all below maximum threshold values. Strong positive correlations were found between EOCs concentration, number of detected compounds, and nitrates in the Cetina River, indicating a common origin, most likely wastewater. Identification of persistent EOCs including widely used repellent N,N-diethyl-metatoluamide (DEET) during base flow conditions and its strong positive correlation with the Ca2+ content in both the Cetina and Jadro samples, suggests potential storage in the epikarst and aquifer matrix. This coupling of conventional hydrochemical indicators and novel markers of anthropogenic impacts, including EOCs, in vulnerable karst water resources is a crucial advancement in the assessment and management of emerging environmental and potential human health risks. Such an approach is pivotal for the sustainable protection of hydrogeologically intricate sites. [ABSTRACT FROM AUTHOR]

The Sor and Gebba watershed plays a crucial role in the water resources of the Baro-Akobo River Basin. However, various factors have had a detrimental effect on the watershed. Unplanned groundwater extraction, wetland drainage, surface water pollution, and land use changes have all intensified due to population growth, urbanization, commercial farms, industrial development, poor water resources management, and improvements in living standards. This research utilized major hydrochemical ions and environmentally stable isotopes to elucidate the interaction between groundwater and surface water in the watershed, which are reliable tracers in various hydrologic processes. During the 2020 wet season and 2022 dry season, over 25 meteoric water samples were collected from different locations for hydrochemical and isotopic analysis. The hydrochemical analysis revealed that the dominant water type is Ca–Mg–HCO3−. Among the anions, HCO3− was the most dominant, followed by NO3−, Cl−, and SO42−, and those of cations Ca2+, followed by Na+, Mg2+, and K+. The spatial analysis of environmentally stable isotopes confirmed the interaction between groundwater and surface water in the watershed. The quality of groundwater is primarily influenced by rock-water interaction (Gibb's diagram) and, to some extent, by evaporation (Isotope study). A graph of the water samples closely aligned with the Addis Ababa-local meteoric water line indicates their meteoric origin. However, there was a slight deviation to the left due to the effects of distance and altitude. The isotopic correlation further supported the interaction between different water sources. [ABSTRACT FROM AUTHOR]

River water quality is closely related to the major ion sources and hydrological conditions. However, there is a limited cognition about the geochemical sources and the seasonal variations of major ions. Thus, in this study, a total of 90 water samples were collected from the Longjiang River and its three tributaries in the dry and wet seasons. The samples were analyzed, including major ion concentrations and physicochemical parameters. Statistical analysis, such as correlation analysis and principal component analysis (PCA), was employed to investigate the spatial and seasonal variations in major ion composition and their respective sources. Our study revealed that the predominant major ions in the studied samples are Ca2+, Mg2+, HCO − 3, and SO2 − 4. Most of ions exhibited notable spatial disparities attributable to variations in geological settings and human activities. Regions characterized by igneous rock outcrops tend to exhibit higher levels of K+ and Na+, while areas with higher population densities in the middle and downstream segments show elevated concentrations of Cl−, NO − 3, SO2 − 4, Na+, and K+. The observed peak SO2 − 4 levels may be attributed to active mining operations. Most parameters displayed higher values in flood season than those in dry season due to dilution effects. Stoichiometric analysis indicated that carbonate weathering inputs contribute to over 85% of the mean total cation concentrations in the water, followed by contributions from silicates, atmospheric deposition, and anthropogenic inputs. On the whole, although the water quality remains non-polluted and is suitable for drinking and irrigation purposes, the enrichment of SO2 − 4 and NO − 3 may contribute to water eutrophication. Caution is warranted during the dry season due to reduced water flow resulting from dam interceptions and limited dilution capacity, potentially leading to elevated pollutant concentrations. Taken together, our results provided a scientific basis for water quality managements of monsoon rivers. [ABSTRACT FROM AUTHOR]

Flow influences major ion concentrations in river water, therefore, it seems that it can differentiate ion concentrations in mountain rivers in different hydrological years. This study aimed to determine the impact of flow on the major ion concentrations in the Carpathian Raba River above and below the Dobczyce Reservoir (southern Poland) in hydrologically dry (HD), average (HA), and wet (HW) years (period April–October) in the period 2010–2017. In the river above the reservoir, the flow negatively affected the concentrations of most major ions under all hydrological conditions, which resulted in their significant differences between (1) the studied hydrological years (except for SO42−)–higher in the HD years than in the HA or HW years–and (2) seasons–higher Mg2+, Na+, K+, Cl−, and SO42− concentrations (mainly point sources of pollution) were identified in summer or autumn than in spring in the HD and HA years. The dam reservoir strongly modified the ion concentrations in the downstream river. It significantly decreased all major ion concentrations only in the HD years, when they were high in the upstream river, and Ca2+, Mg2+, or HCO3− concentrations in all the studied hydrological years. There, the ion concentrations were not related to the flow that resulted in their insignificant differences between the studied hydrological years (with the exception of HCO3−, Ca2+, and Cl−) and different seasonal changes to those in the river above the dam. The obtained results allow for predicting conditions favouring an increase in the salinity of mountain river waters; therefore, they are important for appropriate management and water use opportunities. [ABSTRACT FROM AUTHOR]

The article focuses on the results of water parameters (COD, pH, electrical conductivity) and the contents of major ions (Ca2+, Mg2+, Na+, K+, , , Cl–, , ) and trace elements (Co, Ni, Cu, Zn, Cd, Pb, Sr, Ba, Mn) for 12 springs in the Bogorodsky and Losino-Petrovsky districts of Moscow oblast. The waters are slightly acidic to near-neutral (pH 5.5–7.5) with the mineralization ranging from 0.07 to 0.5 g/L, the total hardness is 0.63–5.7 mg-eq/L, the water composition is variable. Spring waters are divided into four groups: Cl–SO4–HCO3–(Mg)–Ca, (SO4)–HCO3–Cl–Na–Ca; (Cl)–HCO3–Ca, and mixed. Based on the thermodynamic calculation using the Visual-MINTEQ program, it was found that the predominant dissolved species of Ba, Sr, Mn, Zn, Cd, Ni, and Co in the waters of the surveyed springs are free ions. For Cu and Pb, the factors for the formation of migration species are the predominant anions of water, as well as the presence of organic matter in water. The COD values and nitrogen compound in the waters of individual springs indicate that the formation of the spring water composition is resulted from the infiltration of atmospheric precipitation through the modern sediments subject to anthropogenic loading. The values of other sanitary–chemical indicators (mineralization, pH, total hardness, chlorides, sulfates, magnesium, sodium, manganese), the content of regulated trace elements are lower than their maximum permissible concentrations in drinking water. [ABSTRACT FROM AUTHOR]

This standard operating procedure (SOP) describes an ion chromatography (IC) procedure for the major cations and anions in hydrothermal fluids. Hydrothermal fluids are aqueous solutions with a wide range of temperature, salinity, pH and ion species that can be used by microbial metabolism as electron donors and electron acceptors. Due to the high variability of the environmental physical-chemical parameters in these samples, we have developed this protocol taking into account the special features of the matrices analyzed. An Eco IC Metrohm system equipped with a conductivity detector was used. Calibration curves are linear in the 0.1 to 10 mg/L concentration range for cations Ca2+, Na+, K+, Mg2+, NH4 + and anions Cl-, Br-, NO3 -, NO2 -, SO4 2- , PO4 3-.

The Arctic river basins, among the most sensitive regions to climate warming, are experiencing rapid temperature rise and permafrost thawing that profoundly affect their hydrological and hydrochemical systems. However, our understanding of chemical export from Arctic basins to oceans remains limited due to scarce data, particularly in permafrost-dominated regions. This study examines the spatiotemporal variations and seasonal dynamics of major ions (Na+, K+, Mg2+, Ca2+, Cl−, SO42−) and dissolved organic carbon (DOC) concentrations across three river basins with varying permafrost extents: the Severnaya Dvina (2006–2008, 2012–2014), the Pechora (2016–2019) and the Taz Rivers (2016–2020). All the data were sourced from published Chemical Geological researches and were taken from Mendeley and PANGAEA datasets. Our results showed that DOC concentrations ranged from 1.75 to 26.40 mg/L, with the Severnaya Dvina River exhibiting the highest levels of DOC concentrations, alongside significantly elevated ion concentrations compared to the other two basins. A positive correlation was observed between DOC concentrations and river discharge, with peaks during the spring flood and summer baseflow due to leaching processes. The Severnaya Dvina and Pechora Rivers exhibited the highest DOC values during the spring flood, reaching 26.40 mg/L and 8.07 mg/L, respectively. In contrast, the Taz River had the highest runoff during the spring flood season, but the DOC concentration reached its highest value of 11.69 mg/L in the summer. Specifically, a 1% increase in river discharge corresponded to a 1.25% rise in DOC concentrations in the Severnaya Dvina River and a 1.04% increase in the Pechora River, while there was no significant correlation between runoff and DOC concentrations in the Taz River. Major ion concentrations demonstrated a negative correlation with river discharge, remaining relatively high during winter low-flow period. A robust power-law relationship between river discharge and concentration of DOC and major ions was observed, with distinct variations across the three river basins depending on permafrost extent. The Pechora and Taz Rivers, characterized by extensive permafrost, exhibited increasing trends in river discharge and DOC concentrations, accompanied by decreasing major ion concentrations, whereas the non-permafrost-dominated Severnaya Dvina River basin showed the opposite pattern. The Taz River, with the most extensive permafrost, also displayed a delayed DOC peak and more complex seasonal ion concentration patterns. These findings highlight the importance of varying permafrost extents and their implications for water quality and environmental protection in these vulnerable regions.

This study aims to determine the concentrations of fluoride, nitrite, nitrate, chloride, sulfate, phosphate, calcium, sodium, magnesium, ammonium, and potassium ions in different natural spring water brands available in the markets using ion chromatography. The ion chromatography technique is an accurate, sensitive, and reliable method for determining sample anion and cation concentrations. Measurement range, calibration, method detection level, repeatability, precision, recovery, and standard deviation were evaluated to assess the suitability of the method. The R2 values of anion and cation calibration plots were good (greater than 0.994) in this method. The recovery values for low and high concentrations changed from 101 to 111% and from 97 to 104%, respectively. The concentration results were used for human health risk assessment, using Chronic Daily Intake of nitrate and fluoride. The potential adverse health effects of fluoride intake were less than 1 for adults, so there is no potential risk. Moreover, our results suggest that there is a risk for dental decay according to the fluoride limits in spring water recommended by the World Health Organization. [ABSTRACT FROM AUTHOR]

Achibo-Sombo mine is the first underground coal mine in Ethiopia and is in operation for more than a decade. It is a small-scale, semi-mechanized, and mined using room and pillar method. Most of the mining operations are being carried out manually. The coal deposit is inter-trappean, sandwiched between basaltic flows. Seepage is a common problem in the mine. Its intensity varies in three openings and is being drained out by gravity. A preliminary study was conducted to assess the quality of water in the mine. Ten water samples collected randomly from three openings were analysed for major anions using standard colorimetric methods and elemental concentrations using ICP-MS. The results indicate that the concentrations for sulphur, manganese, and iron is relatively higher. The concentration of toxic elements like Cd, As, Hg, and Se is relatively low except Zn. Increased amounts of sulphate in water indicate the sulfides as the source and their chemical breakdown. The relatively higher amount of dissolved sulfur is expected to produce acid mine drainage with time. [ABSTRACT FROM AUTHOR]

Rivers originating from the Himalayas play a crucial role as primary water sources for a significant proportion of the population in Asia downstream. This paper presents a comprehensive synthesis of hydrogeochemical data, incorporating major ions and trace elements from 153 papers spanning 2000 to 2023, with a detailed analysis of 20 papers specific to Nepal Himalayan rivers. To bridge the research gap due to sparse data, we aimed to enhance inclusivity by amalgamating both seasonal and one-time datasets, computing mean values for singular instances, and employing grand means for multiple seasonal data points. Our findings highlight varied research attention across different river basins, with the eastern Koshi Basin receiving extensive attention, while the middle Gandaki and Bagmati Basins garner moderate attention, and data scarcity observed in the western Karnali Basin. Predominant ionic composition, notably Ca2+ and HCO3–, reflect lithological influences, primarily driven by rock weathering. Although anthropogenic impacts remain minimal in most basins, certain lowland areas with higher population densities exhibit increasing significance. Trace element contamination, notably Cd, Cu, Sr, and Zn, poses ongoing threats, both from natural and anthropogenic sources. Water quality assessments conducted for agricultural and drinking suitability indicated good status, except in the densely polluted urban Bagmati stem. Health and ecological risks are low, as determined by pollution indices such as Pi, NPI, HI, and CI. The Bagmati River's middle segment, with high population density and moderate agricultural activity, shows pronounced anthropogenic footprints, while downstream areas exhibited greater impacts. Additionally, this article proposes the potential use of a Water Quality Index tool to comprehensively assess water quality across all parameters in Himalayan water bodies, providing a roadmap for future environmental conservation in the Himalayas. This pioneering review represents a significant effort to understand Himalayan rivers geochemistry on a large geographical scale and emphasizes the need for integrated observation and consideration of river water quality across the entire Himalayan region, from high mountains to lowlands.

Relevance. Tense ecological situation in the impact zone of the large industrial complex of Usolye-Sibirskoe on the Angara river, search for sources and ways of pollutants inflow during different periods of technogenic load, necessary to assess and forecast the current changes in the aquatic ecosystem. Aim. To study chemical composition of wastewater from the industrial zone of Usolye-Sibirskoe during different periods of technogenic load and assess their impact on hydrochemical parameters of the Angara river water. Objects. Wastewater from the industrial zone of Usolye-Sibirskoe and Angara river waters in the impact area during the period of high technogenic load (2010) and the period of its reduction (2020). Methods. Chemical composition of wastewater and natural water was determined in the Center of Collective Use «Isotope-Geochemical Investigations» of Vinogradov Institute of Geochemistry SB RAS (Irkutsk, Russia). Concentrations of major ions in waters were measured using a set of methods generally accepted in hydrochemistry (atomic absorption and atomic emission flame spectrometry, spectrophotometry, potentiometry, titrimetry), Hg concentration was measured using atomic absorption spectrometry, concentrations of other trace elements – using mass spectrometry method (ISP MS). Results. The authors have revealed significant changes in chemical composition of wastewater of the industrial zone in different periods of technogenic load, reflecting the transformation of pollution sources during the liquidation of technogenic objects of the area. Over the ten-year period particularly important changes are expressed in a significant decrease of Hg, Al, Cs, Ti, Cr, Cl– and Na+ concentrations and increase of Mn concentrations in the wastewater of the industrial zone. This is reflected, in its turn, in the dynamics of hydrochemical composition of Angara river water in the impact area. In 2010 a regular consecutive decrease of most of elements concentrations was observed with distance of Angara river waters from technogenic sources. Where as in 2020 their spatial distribution is opposite: with a significant decrease in concentrations of most of the studied elements at the river site 50 m downstream of industrial discharges, their increase was detected at more distant monitoring stations (1.5 and 5 km) where Mn, Cu, Cd and Tl concentrations were the highest. Despite significant changes in wastewater chemical composition in different periods of technogenic load, the Angara river waters at all monitoring stations in the impact zone of the industrial complex of Usolye-Sibirskoe are polluted.

Inter Basin Water Transfer (IBWT) is a water resource stressor globally with negative environmental impacts. This study describes the major ions and hydrochemistry of the first ever ongoing IBWT from snow-fed Bheri River to rain-fed Babai River in Western Nepal. Water samples from 10 sites, five from each river system, were collected in HDPE bottles for major ions (Ca^(2+), Mg^(2+), Na^+, K^+, HCO_3^-, Cl^-, SO_4^(2-), NO_3^-, CO_3^(2-)) along with the estimation of pH, temperature and conductivity encompassing winter, spring, summer, and autumn in 2018. Ca^(2+)and HCO_3^- were the most dominant cation and anion, respectively, with 〖Ca-Mg-HCO〗_3 water type in both the river systems. Mann Whitney test revealed significant variation (p

Relevance. The necessity to control the hydrochemical regime of water bodies significantly affected by anthropogenic impacts. Aim. To study the spatial distribution of major ions and trace element concentrations and identify natural and anthropogenic formation factors of the hydrochemical composition of the Vikhoreva river and Ust-Vikhorevsky bay of the Ust-Ilimsk reservoir. Objects. Waters of the Vikhoreva river before and after inflow of wastewater from the Bratsk industrial zone, waters of the Ust-Vikhorevsky bay (Vikhorevskaya and Burdoyskaya parts) of the Ust-Ilimsk reservoir. Methods. Determination of micronutrients concentrations in water was performed by inductive coupled plasma mass spectrometry, mercury – by atomic absorption method. Cations and anions were determined using standard methods accepted in hydrochemical studies, Sorg – by titrimetric method, oxygen – by iodometric method. Results. In the Vihoreva river water after wastewater inflow from the Bratsk industrial zone, significant transformations of its hydrochemical composition were detected. Along the water area of river decrease of O2 concentrations (up to 0.3 mg O2/l) and increase of Сorg (up to 131 mg/l), SO42– (up to 262 mg/l), K+ (up to 10.6 mg/l), Cl– (up to 220 mg/l), Na+ (up to 240 mg/l), Mn (up to 248.5 mg/l), Cr (up to 7.4 mg/l), to a lesser extent Al (up to 224.1 mg/l), Co (up to 0.26 mg/l), Cu (up to 5.4 mg/l), Zn (up to 43.2 mg/l), Cd (up to 0.126 mg/l), Pb (up to 0.40 mg/l), Hg (up to 0.0032 mg/l) are observed. In surface waters of the Ust-Vikhorevsky bay concentrations of most components of the main ionic composition and trace elements decrease, as compared to the Vikhoreva river water. Maximum concentrations of Mn (511.5 mg/l), Fe (1567.2 mg/l), Co (0.80 mg/l), Pb (0.77 mg/l) were detected in bottom waters. The main ionic composition and trace element concentrations in the Vihoreva river water are determined primarily by anthropogenic factor. At the same time, the hydrochemical regime of the river is effected by natural factors. Inflow of both waters of the highly polluted and forming waters of the channel part of the Ust-Ilimsk reservoir impacts the hydrochemistry of the Ust-Vikhorevsky bay.

Study region: Soda-Saline Lakes in eastern Tanzania's rift valley. Study focus: This study examined the chemical composition, classification, and geographical distribution of soda-saline lakes in the eastern Tanzania rift valley. New hydrological insight of the region: The results revealed that lake water pH ranged from 9.0 to 10.2, EC ranged from 2843 to 109,800 µS/cm, and Na+ dominated over other cations with mixed dominance of HCO3- + CO32-, Cl-, and SO42-. The study also revealed that lakes Balangida and Balangida Lelu had higher sulphate levels than the other lakes, presumably due to sulfate-rich bedrock and local agricultural input. The study suggests that trace elements and heavy metals in lake water depend on their geology, past usage, and specific environmental conditions. The saturation index (SI) showed that the lakes were oversaturated with dolomite, calcite, and aragonite but undersaturated with anhydrite, gypsum, and halite. Lakes Natron and Manyara are classified as soda types, lakes Balangida and Eyasi are classified as soda-saline types; and lakes Singidani, Kindai, Mikuyu, Balangida Lalu, and Sulunga are classified as saline types. The geographical distribution patterns showed that soda-type and soda-saline lakes were most common in northern Tanzania (Arusha and Manyara). In contrast, saline-type lakes were common in the central regions between Dodoma and Singida. The dominant volcanic nature in the northern part possibly influences soda and soda-saline types.

The Irkutsk Reservoir, belonging to the largest unified freshwater Baikal–Angara system, is an important source of drinking water in the region. Therefore, studies of its hydrochemical characteristics are of prime importance in deciding on the role of anthropogenic activity in water quality. The water samples were collected across the reservoir in 2007, 2012, and 2021 and then were analyzed for major ions and trace elements. The data revealed that the distribution of HCO3−, SO42−, Cl−, Ca2+, Mg2+, Na+ and K+ is stable across the reservoir. Trace element concentrations varied from 1.13 to 15.39 µg L−1 for Al, from

−1 for Cr, from 0.39 to 23.12 µg L−1 for Mn, from 1.25 to 53.22 µg L−1 for Fe, from 0.005 to 0.100 µg L−1 for Co, from 0.20 to 1.98 µg L−1 for Cu, from

−1 for Zn, from 0.25 to 0.48 µg L−1 for As, from 0.004 to 0.127 µg L−1 for Cd, from

−1 for Sn, from

−1 for Cs, from

−1 for Pb, from

−1 for Th, and from 0.27 to 0.75 µg L−1 for U. The concentrations of all major ions and trace elements in water were below the drinking water standards. CF values showed considerable and high contamination of samples with Al, Mn, Fe, Co, Cu, Cd, Sn, Pb, and Th. PLI values classified the majority of water samples as water with baseline levels of pollutants, and part of the samples was classified as either polluted or highly polluted. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi National Journal of Earth Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Manchar Lake, Pakistan’s biggest lake in the arid zone, faces human-induced salinity issues. This study investigated its effects on the multifaceted ecosystem services, including serving as a source of drinking and irrigation water and aquatic health through assessing fish diversity and characteristics. Analyses of 189 water samples from 21 sites revealed spatiotemporal variations in major ions contributing to lake water salinity. The study assessed water suitability for drinking and agriculture using the water quality index (WQI), sodium adsorption ratio (SAR), magnesium hazard (MH), sodium percent (Na%), and Kelly’s ratio (KR). The WQI, ranging from 141 to 408, indicated that the lake water was unfit for drinking. In some seasons, such as the pre-monsoon period, the lake water was deemed unsuitable for irrigation due to high SAR values (18 ± 4 g/L, average ± standard deviation), consistently rising MH values exceeding 66 in all seasons and elevated sodium percentages surpassing 66% in both the pre-monsoon and monsoon seasons. The KR remained acceptable (averaging 0.8 to 2.5) in all seasons. Fish health in highly saline conditions was assessed using data from interviews, focus group discussions, and fish sampling (1684 fish from 10 sites). Results depicted that high salt contamination severely impacted fish length and weight. The study found low richness (Simpson’s biodiversity: 0.697 and Shannon Weaver: 1.51) and evenness (Pielou’s index: 0.48) among the fish populations. Since 1998, Manchar Lake has seen a decline in fish varieties from 32 to 23, with changes in fish species’ feeding habits. To improve lake water quality, the study recommends diverting saline water to the sea before and after the monsoon season while utilizing freshwater from alternative sources to fill any water deficit. [ABSTRACT FROM AUTHOR]

New hydrochemical measurements from the Syr Darya provide insights into factors affecting the composition and quality of a major freshwater source replenishing the Aral Sea. This river is heavily used for power and irrigation and crosses territories of four Central Asia republics. It is intensely managed, draining several major tributaries, many reservoirs, and numerous irrigation distribution systems and canals. Analysis of seasonal changes in dissolved ion concentrations using geochemical diagrams, elemental ratios, statistical correlation, and equilibrium modeling allowed the characterization of mineral formation processes that control the dissolved chemical composition. Measured water hydrochemistry and composition type differs substantially from previous reports from the upper reaches of the Syr Darya in Kyrgyzstan. Element ratios, statistical correlation, and the presence of NO3- and NO2- suggest that the downstream trend of increasing total dissolved solids (TDS) from Zhetysay city to the Aral Sea in June is controlled by evaporation–crystallization processes, which contribute to the river dissolved load through soil runoff and return irrigation waters following leaching of secondary salts. Downstream sample composition during the growing season shows significant changes in magnesium-to-calcium ratios in the river water. Elevated magnesium levels in Syr Darya waters may pose a problem to sustainable uses for irrigation. HIGHLIGHTS Water composition transitions from Ca–Mg–HCO3 to Ca–Mg–SO4–Cl to Na–SO4–Cl downstream the Syr Darya.; Seasonal and downstream differences in composition suggest that irrigation water inputs are likely controlled by different mineral equilibria.; Water quality indices showed that, generally, Syr Darya water is suitable for irrigation.;

Inter Basin Water Transfer (IBWT) is a water resource stressor globally with negative environmental impacts. This study describes the major ions and hydrochemistry of the first ever ongoing IBWT from snow-fed Bheri River to rain-fed Babai River in Western Nepal. Water samples from 10 sites, five from each river system, were collected in HDPE bottles for major ions (Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, SO42-, NO3-, CO32-) along with the estimation of pH, temperature and conductivity encompassing winter, spring, summer, and autumn in 2018. Ca2+ and HCO3- were the most dominant cation and anion, respectively, with Ca - Mg - HCO3 water type in both the river systems. Mann Whitney test revealed significant variation (p<0.05) between the two river systems with regard to Ca2+, Mg2+, HCO3-, and SO42- Kruskall Wallis test revealed significant variations between seasons in pH, temperature, Na+, K+, and Cl- in Bheri River system, and in pH, TDS, temperature, Na+, K+, Cl- and SO42- in Babai River system. Carbonate weathering was the main mechanism of ionic sources with insignificant contribution from silicate weathering. Relatively higher concentrations of the major ions during the dry seasons probably indicate the dilution effect of monsoon. Higher concentrations of the ions in the Babai River system reflect the latter's bedrock geology with susceptibility to erosion. With Nepal's future plans of IBWTs and their environmental implications, this finding could be helpful in mitigating the negative consequences of IBWTs in the impact assessment and management of IBWT projects because of their implications on management of aquatic resources. [ABSTRACT FROM AUTHOR]

The use of concentration–streamflow (C–Q) relationships is presented as a novel approach for studying climate change effects on water quality. Based on data from nine monitoring stations in the Choapa basin, north-central Chile, constituent behaviours were classified as constancy, enrichment or dilution. Constancy was shown for B, As, and Cu. Dilution and enrichment relationships were observed at some sites. Electrical conductivity and major ions showed dilution behaviour, with Na+, Mg2+, Cl−, SO4−2 and K+ showing greater variability in response to streamflow changes. Fe, Al, Mn and Zn presented enrichment behaviour, with Al and Fe showing greater variability. Based on historical C-Q relationships and available projections of streamflow variations under climate change, the change in constituent concentrations from 2010 to 2040 likely will not exceed ±10% with respect to the historical average, and ±15% from 2040 to 2070. In particular, Fe and Mn require special attention in the future. [ABSTRACT FROM AUTHOR]

Atmospheric bulk and wet deposition samples were collected simultaneously at the background coastal site in the Eastern Middle Adriatic region in order to assess the impact of major ions (Cl−, NO3−, SO42−, Na+, K+, NH4+, Mg2+, Ca2+) on deposition acidity and distinguish the main sources. Higher ion levels were observed during the cold period, especially for Cl−, Na+, Mg2+ and K+. Dust intrusion caused significant increases in levels of Ca2+, Mg2+ and K+, while open-fire events increased the levels of K+. Deposition acidity showed seasonal differences as well as the influence of dust intrusion. Low ionic balance ratios indicated acidic deposition properties and the presence of organic anions. The highest neutralization ability was found for Ca2+, Na+ and NH4+. Several natural (marine, crustal) and anthropogenic sources were determined, as well as the formation of secondary aerosols. Wet deposition was characterized by higher contribution of sea salt fraction compared to bulk deposition and lower contribution of crustal fraction. [ABSTRACT FROM AUTHOR]

The relevance of the research is caused by the necessity of controlling hydrochemical parameters of large freshwater ecosystem for the objective estimation of waterbody transformation under the anthropogenic impact. The main aim of the research is to examine the spatial and temporal variability in major ion concentrations in Angara River water before regulating its flow by the Boguchany hydropower plants dam, as well as in Boguchany reservoir water during filling and water level stabilization. Objects of the research are the Angara River before regulating its flow by the Boguchany HPP dam (2007), and Boguchany reservoir during filling (2013, 2014) and water level stabilization (2015, 2017). Methods. Chemical analyses in the water samples were determined in the Centre for Collective Use «Isotope-Geochemical Research» of the IGC SB RAS (Irkutsk, Russia). Flame emission spectrophotometry was used in the analysis of Na+ and K+, atomic absorption spectrometry was applied to analyse Ca2+ and Mg2+, the turbidimetric method was used to measure SO42–, the titrimetric method was employed in the analysis of HCO3– and the mercurimetric method was applied to study Cl–. Results. The spatial and temporal variability in the concentrations of cations (Ca2+, Mg2+, Na+, and K+) and anions (HCO3–, SO42–, and Cl–) was examined. The results of the study show that the increase in the water level led to changes in the major ion concentration ratio. In comparison with the Angara River, in the Boguchany reservoir operation, SO42–, Cl–, Na+, and Mg2+ concentrations increased, while HCO3– and Ca2+ concentrations decreased in the initial period of reservoir operation. The ionic composition of water in the Boguchany reservoir resulted primarily from the contribution from the area located upstream (runoff from the Ust-Ilimsk reservoir). Anthropogenic factors include wastewater and reservoir creation, which affect the hydrochemistry of major ions.

Identification of sources and transport pathways of heavy metals and major ions is crucial for effective water quality monitoring, particularly in large river systems. The Ganges river basin, the largest and the most populous river basin in India, remains poorly studied in this regard. We conducted a basin-level analysis of major ions, heavy metals, and stable isotopes of nitrate in the Ganges during the pre-monsoon season to constrain the sources and quantify the inorganic chemical composition of the river during its lean flow. Bedrock weathering, anthropogenic interferences, water contribution through tributaries, and surface water-groundwater interaction were identified as the major driver of metal and ion variability in the river. Heavy metals showed the highest concentrations in the upper section of the river, whereas ionic loads were the most variable in the middle. We find a significant impact of tributaries on the metal and ion concentrations of the Ganges in its lower reaches. Isotopic analysis of dissolved nitrate suggested synthetic fertilizers and industrial wastes as the main sources. We find that the otherwise clean waters of the Ganges can show high ionic/metallic concentrations at isolated stretches (As: up to 36 µg/L), suggesting frequent monitoring in the source region to maintain water quality. Except for water collected from the Yamuna and Kannauj in the middle stretch and the Alaknanda and Rishikesh in the upper stretch, the WQI showed acceptable water quality for the sampled stations. These findings provide an insight into the modifications of dissolved inorganic chemical loads and their sources in different sections of the basin, needed for mitigating site-specific pollution in the river, and a roadmap for evaluating chemical loads in other rivers of the world. [ABSTRACT FROM AUTHOR]

To explore the latitudinal distributions, sources and formation mechanisms of total carbon (TC), nitrogen (TN), sulfur (TS) and water‐soluble major ions (Na+, Cl−, SO42−, K+, nss‐SO42−, NH4+, NO3−, and MSA−), marine aerosol samples were collected over the Western Pacific (WP) and Southern Ocean (SO) from November 1994 to February 1995. Concentrations of TC ranged 30–390 ng m−3 (av. 190 ng m−3) over the SO, which are six times lower than those (1,200 ng m−3) over the WP, whereas concentrations of TN (av. 83 ng m−3) in the SO are three times lower than those (av. 232 ng m−3) over the WP. The highest concentrations of TC and TN were observed near New Zealand (7,000 and 720 ng m−3, respectively), suggesting a continental influence over the marine atmosphere. NO3−, tracer of anthropogenic sources, showed higher concentrations over the WP, whereas NH4+ concentrations over the SO are higher than the WP. The latter may be associated with penguin‐derived guano droppings from Antarctica. The concentration trends and statistical analysis demonstrate that the formation mechanisms of MSA− over the SO and WP is different. We found a strong correlation between MSA− and liquid water content (LWC) over the WP, suggesting the heterogenous aqueous phase production of MSA−, whereas aqueous phase reaction is less important over the SO. The strong correlation (R2 = 0.97) between nss‐Ca2+ and ss‐Ca2+ together with their similar relative abundances demonstrates an influence of CaCO3 eroded from coral reefs and shells and subsequent emission to the atmosphere by bubble bursting process. Plain Language Summary: Major ions in the marine aerosols are important constituents with various sources. The ionic composition and sources are studied via the oceanic cruise over the Western Pacific (WP) and Southern Ocean (SO). Total carbon (TC), total nitrogen (TN) and total sulfur (TS) are disclosed for the first time over the SO. Marine aerosols collected over the WP is influenced by the anthropogenic sources in the Asian continent. There are several penguin colonies in Antarctica, which may be the source for the abundant presence of NH4+ over the SO emitted from the penguin‐derived guano. Coral reefs eroded from the ocean may have an influence on the marine atmosphere. Biomass burning tracers also affect the pristine marine atmosphere in the SO. The formation of methanesulfonic acid (MSA) from dimethylsulfide (DMS) over the WP and SO is different. Solid, liquid and gas‐phase reactions contribute to the formation of the MSA in the WP, whereas different kind of mechanisms such as free radical mechanism may be involved over the SO. Long term study is needed to reveal the exact formation mechanism of MSA from DMS over the SO. Key Points: Total carbon, Total nitrogen and total sulfur over the Western Pacific and Southern Oceanwater‐soluble major ions (Na+, Cl−, SO42−, K+, nss‐SO42−, NH4+, NO3−, and MSA−) in the marine atmosphereErosion of coral reefs and shells and subsequent emission to the atmosphere by bubble bursting process [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tiangong University is the property of Journal of Tianjin Polytechnic University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

More than 40 years of aerosol data including concentrations of particle number and of nine major ions collected over the Southern Ocean and coastal stations have been aggregated and filtered with back trajectories to reduce the risk of influence from adjacent continents. That provided a rich dataset including latitudinal distribution and seasonality of physical and chemical aerosol parameters that allow insights into aerosol sources over the Southern Ocean. These data together with statistics of back trajectory paths of high (75% percentile) and low (25% percentile) concentrations of the studied aerosol parameters were used to identify potential source regions of the respective compounds. For particle number concentrations, MSA, and the non-sea-salt fractions of Ca and potassium the most prominent source regions were found in high DMS-areas close to Antarctica, whereas the potential source regions of NH4 and the non-sea-salt fraction of Mg were located in part further north over the Southern Ocean. These geographical differences would reflect differences in the marine biota.

Municipal solid waste landfills leachate can cause serious environmental issues for groundwater quality. Therefore, the application of environmental tracing methods to identify groundwater contamination by municipal solid waste landfills leachate is significant. Hydrogeochemical evaluations to trace municipal solid waste landfills leachate are usually carried out. The study was carried out at a landfill in central Italy (Umbria). Samples of leachate and groundwater have been analyzed to evaluate the impact of leachates on groundwater through the comparison of their hydrogeochemical nature. Parameters like pH, Temperature (T), Electrical Conductivity (EC), redox potential (Eh) and Chemical Oxygen Demand (COD) were also measured in situ using digital instruments. Hydrogeochemical data (Na+, K+, Mg2+, Ca2+, SO42−, HCO3−, Cl−, NO3−), ionic ratios and geochemical correlations were used to confirm the processes that govern the chemistry of the spring water and to identify leachate contamination phenomena. In fact, the main geochemical diagrams (Langelier-Ludwig, Piper, Schoeller) confirm the leachate contamination in a groundwater sample. In particular, the Piper diagram shows that a sample is in Na+ – Cl- – HCO3- mixing zone, indicating a possible influence of the leachate on groundwater chemistry. As a matter of fact, some correlations between major elements, such as Cl- versus Na+ and Cl- versus HCO3-, confirm that the leachate in this study area is highly enriched in Cl- and HCO3- due to wastes dissolution and degradation processes. Further, the assessment of K+/Mg2+ ratio also confirms the presence of a sample heavily impacted from leachate contamination. These results indicate that also one basic hydrogeochemical study can be useful for fingerprinting the leachate pollution for groundwater samples.

Recent studies have endorsed that surface water chemical composition in the Himalayas is impacted by climate change–induced accelerated melting of glaciers. Chemical weathering dynamics in the Ladakh region is poorly understood, due to unavailability of in situ dataset. The aim of the present study is to investigate how the two distinct catchments (Lato and Stok) drive the meltwater chemistry of the Indus River and its tributary, in the Western Himalayas. Water samples were collected from two glaciated catchments (Lato and Stok), Chabe Nama (tributary) and the Indus River in Ladakh. The mildly alkaline pH (range 7.3–8.5) and fluctuating ionic trend of the meltwater samples reflected the distinct geology and weathering patterns of the Upper Indus Basin (UIB). Gibbs plot and mixing diagram revealed rock weathering outweighed evaporation and precipitation. The strong associations between Ca2+-HCO3−, Mg2+-HCO3−, Ca2+-Mg2+, Na+-HCO3−, and Mg2+-Na+ demonstrated carbonate rock weathering contributed to the major ion influx. Principal component analysis (PCA) marked carbonate and silicates as the most abundant minerals respectively. Chemical weathering patterns were predominantly controlled by percentage of glacierized area and basin runoff. Thus, Lato with the larger glacierized area (~ 25%) and higher runoff contributed low TDS, HCO3−, Ca2+, and Na+ and exhibited higher chemical weathering, whereas lower chemical weathering was evinced at Stok with the smaller glacierized area (~ 5%). In contrast, the carbonate weathering rate (CWR) of larger glacierized catchments (Lato) exhibits higher average value of 15.7 t/km2/year as compared to smaller glacierized catchment (Stok) with lower average value 6.69 t/km2/year. However, CWR is high in both the catchments compared to silicate weathering rate (SWR). For the first time, in situ datasets for stream water chemical characteristics have been generated for Lato and Stok glaciated catchments in Ladakh, to facilitate healthy ecosystems and livelihoods in the UIB. [ABSTRACT FROM AUTHOR]

We monitored physical–chemical conditions in the North Fork of Clear Creek in Colorado (USA) before, during, and after the start of remediation (lime treatment) to remove metals from two major inputs of acid mine drainage (AMD) water. In addition, we analyzed historical monitoring data that extended back more than two decades. Concentration–discharge (C–D) and load–discharge (L–D) plots accounted for discharge dependence in concentrations and loads of metals, major ions, and other water chemistry parameters. Total and dissolved concentrations, and loads of the metals decreased after remediation began, with the largest decreases usually during low stream flow. However, postremediation concentrations and loads remained slightly to considerably higher than reference, probably because of unidentified groundwater seeps and/or small surface flows. Dissolved Cu concentrations decreased much less than total Cu concentrations, because the percentage of total Cu in the dissolved phase increased considerably as particulate Fe (PFe) concentration decreased. We conclude that 1) water chemistry can change to a new steady state or pseudo‐steady state relatively quickly after major AMD inputs to a stream are remediated; 2) elevated flows during snowmelt and rainfall periods can mobilize additional amounts of major ions and metals, resulting in in‐stream concentrations that are manifestations of both dilution and mobilization; 3) although lime treatment of AMD‐related waters can decrease metal concentrations, it does not decrease elevated concentrations of major ions that might impair sensitive stream invertebrates; 4) although Fe is toxic to aquatic organisms, PFe adsorbs other metals and thereby provides protection against their toxicity; and 5) use of C–D and L–D plots and element ratios can indicate the presence of unidentified AMD inputs to a stream. Environ Toxicol Chem 2023;42:495–511. © 2022 SETAC [ABSTRACT FROM AUTHOR]

Springs are an essential drinking water resource. Therefore, it is necessary to control spring water quality under the increasing anthropogenic pressure on the environment. This study was carried out to evaluate the content of major ions and trace elements in the waters of 28 springs in the Pushkinsky district of the Moscow region. The macro- and micro-component composition of groundwater of various aquifers was characterized according to the sampling data of springs. It is shown that the mean contents of trace elements in the waters of springs were at the level of concentrations characteristic of groundwater in the leaching zone of a temperate climate. Based on the thermodynamic calculation using the Visual-MINTEQ software, it was found that the predominant dissolved forms of Ba, Sr, Fe, Mn, Zn, Cd, Ni, and Co were free ions in the waters of the surveyed springs, while Cu and Pb were mainly presented in the form of carbonate and organic complexes. [ABSTRACT FROM AUTHOR]

More than 40 years of aerosol data including concentrations of particle number and of nine major ions collected over the Southern Ocean and coastal stations have been aggregated and filtered with back trajectories to reduce the risk of influence from adjacent continents. That provided a rich dataset including latitudinal distribution and seasonality of physical and chemical aerosol parameters that allow insights into aerosol sources over the Southern Ocean. These data together with statistics of back trajectory paths of high (75% percentile) and low (25% percentile) concentrations of the studied aerosol parameters were used to identify potential source regions of the respective compounds. For particle number concentrations, MSA, and the non-seasalt fractions of Ca and potassium the most prominent source regions were found in high DMS-areas close to Antarctica, whereas the potential source regions of NH4 and the non-sea-salt fraction of Mg were located in part further north over the Southern Ocean. These geographical differences would reflect differences in the marine biota. [ABSTRACT FROM AUTHOR]

The current study aims to assess the water quality of the Al-Diwaniyah River in the city of Al-Diwaniyah to drink in terms of chemical properties and heavy metals and their impact on the health of the local population. The results showed that most of the parameters in the river water are of low concentrations due to the limited human activities in polluting the river water. The study concluded that the water quality is suitable for drinking depending on major cations and anions in all seasons. The Heavy Metal Pollution Index (HPI) showed that the river water was clean and safe, except two slightly polluted samples. The study concluded that river water for drinking or various domestic uses does not pose any danger to human health if there are no other polluting factors. [ABSTRACT FROM AUTHOR]

Major ions and nutrient chemistry of surface water from the Devi river estuary, eastern India has been studied in order to understand the governing biogeochemical processes. Concentration of Na, K, Ca, Mg, Cl, SO4 and PO4 increases toward higher salinity; however, NO3 and dissolved silica (DSi) decreases from upper to lower estuary. All major ions, except NO3 and DSi, show the highest and lowest concentration in summer and monsoon season, respectively. Increased surface runoff has resulted in the highest concentration of NO3 and DSi in the monsoon period. The Na, Cl, SO4, NO3 and PO4 ions show conservative mixing behavior in the estuary throughout the year. Non-conservative behavior of DSi is attributed to the combined process of mineral weathering and biological removal by diatoms. Enrichment and depletion of Ca and Mg in the estuary is owed to carbonate mineral precipitation and dissolution processes. Decreasing carbonate saturation indices (SI) with reducing pH accompanied by lowering of DO% suggests the influence of organic matter degradation on the carbonate precipitation and/or dissolution potential. Nutrient stoichiometric ratios—NO3:PO4, DSi:PO4 and DSi:NO3—are found to vary spatially and seasonally as a result of differences in geochemical processes prevailing in the fresh- and marine-water environment. A prominent PO4 limitation is observed in the upper estuary during summer and winter. However, this limitation reduces toward the lower estuary owing to precipitation of Fe-sulfide under the influence of higher salinity. In contrast, the influx of PO4-limited freshwater into the estuary controls the nutrient stoichiometric ratios in the monsoon season. The spatial variation of chlorophyll concentration in the estuary is in accordance to the nutrient stoichiometric ratios. Thus, this study emphasizes on the role of unique biogeochemical processes in controlling the spatial and seasonal distribution of major ions and nutrient stoichiometry in a tropical estuarine system. [ABSTRACT FROM AUTHOR]

At present, the problem of climate change is becoming increasingly acute. This is especially pressing for Lake Baikal, a World Natural Heritage site. The Russian part of the Selenga watershed is a suitable site for climate change research. The study of changes in precipitation, runoff, and chemical runoff is important for sustainable water resources management. This study presents a trend analysis of precipitation and runoff at hydrological stations and weather stations in the Russian part of the Selenga River basin. A comparative analysis of the concentrations of major ions in the surface water of the Selenga River depending on water levels was also carried out. Analysis of the data series on precipitation revealed a slight negative trend at the Novoselenginsk, Ulan-Ude, and Kabansk stations, and a weak positive trend—at the Kyakhta station. Runoff analysis revealed negative trends at the two used stations (Novoselenginsk and Mostovoi). The hydrochemical regime of the Selenga River is characterized by an increase in major ions and salinity during winter low-water periods, and a decrease during high-water periods. Mineralization and major ion content are lower in the high-water period (2019–2021) than in the low-water period (2015–2017). [ABSTRACT FROM AUTHOR]

The work evaluates the urban snow cover pollution and determines the level of the city influence on the pollution of the urban atmosphere with major ions (ammonium, nitrite, nitrate, chloride, sulfate, phosphate, sodium, potassium, magnesium, calcium) during the winter period (on the case study of Barnaul city, 2014-2019). The priority ions that determine the high pollution of the urban atmosphere in winter are (nitrite, chloride, sodium), the sources of which are the exhaust of motor vehicles (nitrite) and the using of anti-ice reagents (chloride, sodium). The study showed an increase of the major ions in the urban snow cover (with the exception of nitrate ion) by more than two times compared with the regional and more than six times with the global natural background. To study the spatial features of the snow cover pollution interpolation surfaces of the spatial distribution of priority ions in the study area were constructed. [ABSTRACT FROM AUTHOR]