Chemical Composition Of Water Research Articles

Hydrochemical properties and heavy metal concentrations (ecological and human risk) of lake Rukwa

This study examined lake Rukwa's hydrochemical characteristics and heavy metal levels (ecological and health hazards). Results showed that the pH ranged from 8.83 to8.95, EC ranged from 1470 to 1572.22 µS/cm, and TDS ranged from 1053.04 to 1262.63 Mg/l. The findings revealed that lake Rukwa is characterized by Na-K-HCO3 water chemical type. Gibb's diagram revealed that rock weathering and evaporation regulate water's chemical composition. The calcite and sepiolite precipitation enriches the water with Na-CO3-SO4-Cl. The study suggests silicate mineral weathering, rock-water interactions, direct ion exchange, and secondary mineral precipitation govern the geochemical evolution of lake Rukwa. The results also revealed that 30% of samples had moderate ecological risk (30 < RI < 60), whereas 70% had severe risk (60 < RI < 120). The oral hazard quotient (HQ) values for lead (Pb) in children were significantly higher (HQ > 1) at all locations, indicating a potential health risk. However, the dermal HQ values were found to be within acceptable levels. Most sites had acceptable Hazard Index (HI) values, except for Pb in children and adults. In Monte Carlo simulations, heavy metal HQ values were below standard limits, except for oral Pb exposure, which exceeded 1 for adults (7.29E-04) and children (2.79E-03). The average CR values for oral and dermal Pb in adults (7.29E-04, 3.47E-04) and children (2.79E-03, 1.02E-03) exceeded 1.0E-04, suggesting carcinogenic potential. These findings highlight significant oral and dermal carcinogenic hazards from Pb exposure to lake Rukwa and the necessity for effective comprehensive measures to mitigate these risks.

Hydrochemical characteristics of left-bank tributaries of the Dniester within Ternopil Oblast

&#x0D; &#x0D; &#x0D; The purpose of this article is to study the chemical composition of water and the hydrochemical regime of the left-bank tributaries of the Dniester within the Ternopil Oblast at 9 monitoring sites on the Zolota Lypa, Koropets, Strypa, Seret, Nichlava, and Zbruch Rivers. Water quality monitoring data from the State Agency of Water Resources of Ukraine for the period from 1993 to 2020 were used. The hydrographic assessment of the territory following the Water Code of Ukraine showed the presence of two medium-sized rivers (Seret and Zbruch) and four small rivers among the studied rivers. The chemical composition of the water was analyzed by the following groups of components: major ions and water salinity; physicochemical parameters; and biogenic components (nitrogen and phosphorus compounds). It was found that the water of most studied rivers is calcium bicarbonate by hydrochemical type. The water of the Nichlava River is calcium bicarbonate-sulfate. The average annual salinity of the water of the studied rivers varies from 476 mg∙dm-3 to 699 mg∙dm-3. It was determined that the water of most rivers is moderately fresh in terms of mineralization. The water of the Nichlava River is fresh with high mineralization. The hydrochemical regime of rivers is generally related to the hydrological regime. The minimum concentrations of the main ions and salinity values of the studied rivers are observed during the summer-autumn low water mark, which is explained by the significant amount of precipitation and the presence of floods during this period. In winter, the maximums of these indicators are observed. Among the biogenic compounds (ammonium, nitrite, nitrate, phosphate), the clearest manifestation of the hydrochemical regime was recorded for nitrate. The minimum NO3– concentrations are observed in the summer and autumn low-water periods when nitrates are consumed for the development of aquatic plants. In the autumn period, with the death of aquatic plants, nitrates accumulate, and during the winter low water, their maximum average content is observed. The analysis of the monitoring system of the State Agency of Water Resources of Ukraine for the content of the studied components in the water of the left-bank tributaries of the Dniester over a multi-year period for all samples showed that their concentrations were within the regulatory requirements, except for one case. Particularly, in the water of the Nichlava – Borshchiv River, an ammonium concentration of 15 mg∙dm-3 was recorded, which was 7.5 times higher than the standard (August 2, 2000).&#x0D; &#x0D; &#x0D;

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.

Prospects for fisheries use of lake Sobache (Pionerskoe) in the Republic of Khakassia

We assess Sobache (Pionerskoe) lake located in The Republic of Khakassia for aquaculture using. The lake is drainless, the water-surface area is about 1.5 km2. The prevailing depths range from 2 to 4 m. We provide data on the hydrological regime of the lake (temperature, dissolved oxygen level, chemical water composition). 3 species of rotifers, 10 species of cladoceran and 3 species of copepods were found in the zooplankton. The dominant complex consists of the rotifer Asplanhna priodonta, Bosmina longirostris and Ceriodaphnia quadrangula. The zoobenthos community includes 13 groups of organisms, where chironomids predominate in abundance, and gastropods and bivalves predominate in biomass. The ichthyofauna of the lake consists of perch and pike, perch predominates in abundance. Four species of parasites were found, including trematodes and myxporidia. The infection of fish with trematode metacercariae indicates the presence of intermediate hosts in the zoobenthos community of the lake. The detected species of parasites do not pose a danger to human health. The natural fish productivity is estimated at 48.2 kg/ha. We recommended to use the lake for commercial cultivation of fish in polyculture way. We proposed two schemes of fishery exploitation of the lake on the principle of pasturable fish culture: annual cultivation of fish in polyculture (carp, trout, herbivorous fish species) and joint cultivation of fish in polyculture (carp and white amur) by continuous intensive technology (three-year turnover) with carp feeding. The expected yield of fish products varies from 460.0 to 400.0 kg/ha, depending on the chosen technology. These recommendations can contribute to the effective use of the fisheries potential of Sobache (Pionerskoe) lake to provide the region with fresh fish products and create jobs for the local population.

Temporal variability of water chemistry in the Cherkashinskaya well No. 36-RG (Tobolsk district, Tyumen region)

This article focuses on a temporary change in the chemical composition of water in the Cherkashinskaya well No. 36-RG, which is located in the Tobolsk district near the village of Shestakovo. The impact of underground mineral waters on catchments and watercourses can be caused by the open gushing of orphaned geological exploration wells. This can lead to the disturbance of the hydrochemical regime of neighbouring water systems. Publications on this topic are available not only in Tyumen region, but also throughout the Russian Federation. For example, scientific articles and conference proceedings, such as "Groundwater of the East of Russia" (2018), "Issues of studying surface and groundwater of Siberia" (2021), and the International Conference "Underground Waters 2023", are available. The study highlights the behavior of various components of water composition. The article presents changes in the mineralization of groundwater and identifies the main sources of negative impact on its quality. In 2019, the chemical composition of the water in the containing well underwent a transformation. This article focuses on the changes in the chemical composition of water from the Cherkashinskaya well No. 36-RG and its impact on the surrounding areas.

The phenomenon of Peatmass Change and Its Impact on Water Level in The Regenerated Melaleuca Forest Following a Fire Incident in U Minh Thuong National Park, Vietnam

Purpose: The study was conducted in U Minh Thuong National Park to address forest regeneration. Theoretical framework: After a major forest fire in Vietnam, various measures were taken to promote forest regeneration, including afforestation, silvicultural solutions, and hydrological techniques such as rainwater storage to maintain humidity and prevent future fires. Method: Using a drill hand to collect samples at 15 plots to understand forest growth on three thickness levels of a pea. Each site to collect samples is three; each sample was one kg and coded a member of the site as UTM1, UTM2, UTM3, then gets to the Southern Institute of Forestry Science laboratory for analysis. Results and conclusion: There was a relationship between peat chemical indicators and the evolution of the Melaleuca forest. Peat thickness and flooding regime significantly influenced the growth of the Melaleuca forest, while another identified a relationship between peat chemical indicators and forest growth. Peat water's chemical composition changed considerably during the rainy and dry seasons, with nutrient content and pH affecting forest growth. Peat thickness and flooding regime were essential in regulating forest growth. These studies highlight the importance of considering multiple factors, such as peat thickness and chemical properties, when developing effective forest restoration strategies. Implications of the research: By understanding the relationship between peat thickness, chemical properties, and forest growth, forest managers can develop targeted strategies to promote regeneration while minimizing negative impacts on biodiversity. Originality/value: This study explores the relationship between peat thickness, chemical properties, and forest growth in forest regeneration after major fires. It integrates forestry, ecology, and hydrology to provide a holistic understanding of vegetation dynamics and the importance of peatlands in forest regeneration.

Current Ecological State of the Volga-Akhtuba Floodplain Water Bodies (Using the Example of Dudachenok Shallow Channel)

Current ecological state assessment of the water body located on the Volga-Akhtuba floodplain territory (Dudachenok shallow channel) after its environmental rehabilitation was carried out. It was found that almost all the studied indicators correspond to the approved quality standards with the exception of strontium – 4.5 mg/l (MPC – 0.4 mg/l (Order No. 552 dated December 13, 2016), MPC – 7 .0 mg/l (SanPiN 1.2.3685-21 No. 2 dated January 28, 2021)) and barium – 1.25 mg/l (MPC– 0.74 mg/l (Order No. 552 dated December 13, 2016), MPC – 0.7 mg/l (SanPiN 1.2.3685-21 No. 2 dated January 28, 2021)). It is concluded that it is possible to assign a hydrocarbonate class (predominant anion), calcium group (predominant cation) and second type to a water body. A study of bottom sediments revealed that chloride (36 mg/kg) is one of the predominant anions, calcium (27 mg/kg) and sodium (27 mg/kg) are the predominant cations, which agrees with the obtained water chemical composition data. Chemical and toxicological parameters of bottom sediments were analyzed. It was determined that the quantitative content of metals and pesticides does not exceed the maximum permissible concentrations.

Enrichment of arsenic in the Yarlung Tsangpo basin, Southern Tibetan Plateau: Provenance, process, and link with tectonic setting

Geogenic As enrichment is prevalent in freshwater systems worldwide, yet the connection between such enrichment and regional tectonics remains poorly understood, especially within orogenic environments like the Tibetan Plateau. To provide new insights into the sources and processes of arsenic, as well as its relationship with tectonics in the plateau basin, we selected the Yarlung Tsangpo basin, situated at the collision zone between the Indian (Himalaya block) and Eurasian plates (Lhasa block) as the study area. We analyzed and compared the chemical compositions of waters and sediments across various litho-tectonic domains. This also involved assessing arsenic concentrations in river waters, suspended particulate matter (SPM), sediments, geothermal waters, and rocks. The main findings are as follows: (a) High-arsenic geothermal waters and igneous rocks are common in the Lhasa block, and the discharge of these geothermal waters is the main source of dissolved As in river water, whereas erosion of igneous rocks contributes most of the As in sediments. (b) Metal oxides adsorb dissolved As, which leads to further As enrichment in the sediments. (c) The occurrence of high As concentrations in the southern Tibetan Plateau can be explained by a crustal cycling model. Arsenic likely originated in Neo-Tethys oceanic crustal rocks and was concentrated in the upper crust of the active continental margin (Lhasa block) during geological cycling at convergent plate boundaries. These studies highlight the role of tectonic settings on influencing arsenic enrichment in the plateau basin.

ФОРМИРОВАНИЕ ХИМИЧЕСКОГО СОСТАВА ВОД СЕВЕРНОГО БАЙКАЛА В ЗОНЕ СМЕШЕНИЯ С ВОДАМИ ПРИТОКОВ

The results of studying the chemical composition of water in Northern Baikal and in the rivers flowing into it are analyzed. It is shown that the influence of river water on forming the chemical composition of water in this part of the lake is observed at the distance of 1-3 km from the cofferdam separating the Upper Angara delta from Lake Baikal. In spring and early summer, the expansion of river water in the lake is constrained by a thermal bar. In summer, a biological barrier is formed in the mixing zone, where the minimum biogenic element concentrations of and maximum phytoplankton concentrations are registered. The increased concentrations of phosphorus have been revealed in the shallow area in winter, which points to the contamination of bottom sediments and secondary pollution of water. The increased content of phosphorus in the water may be a sign of the eutrophication of Northern Baikal.

Formation of the Chemical Composition of Water in Northern Baikal in the Zone of Mixing with the Water of Its Tributaries

Formation of the Chemical Composition of Water in Northern Baikal in the Zone of Mixing with the Water of Its Tributaries

Seasonal variations and water chemical control mechanism of water quality in a suburban river near a coal city: a case study in the Xinbian River of Suzhou City, Anhui Province, China

Abstract To study the seasonal change rules of water quality indicators and water chemical control mechanisms in the nearby city river Xinbian River, in Suzhou City, Anhui Province, China, nine points were selected and periodically sampled for 12 months. Totally 108 water samples were collected, and basic physical–chemical indicators and routine ions (e.g., Ca2+, Mg2+, Na+, K+, SO42−, Cl−, F−, NO3−, CO32−, and HCO3−) were measured. Piper diagram, Gibbs diagram, and ion ratio method were used. The result shows that the seasonal and upstream-to-downstream variations in pH were less varied, whereas the fluctuation in dissolved oxygen was large. Four ions, namely, SO42-, F−, Cl−, and Na+ generally first decreased overall and then changed from spring to winter. The maximum contents of SO42- (406.03 mg/L), Cl− (250.22 mg/L), and Na+ (269.99 mg/L) in single water samples appeared at the S9 sampling point (Suzhou control gate) in March 2020. The dominant hydrochemical types in summer were Na–Ca–HCO3 and Na–Mg–SO4, while Na–Mg–SO4 and Na–Mg–HCO3 were the main hydrochemical types in the other seasons. The control factors of water chemical composition vary according to the season. However, rock weathering (e.g., silicate dissolution) is the dominant control factor of water chemistry in the studied river section.

How the catchment-river-lake continuum shapes the downstream water quality

Lakes play a crucial role in the nutrient cycling of Earth, despite covering only a small fraction of the planet’s surface. Their interactions with their surrounding catchment areas significantly impact ecosystems and regulatory services. The connection between a lake and its catchment, especially the drainage ratio (catchment area to lake surface area), shapes the characteristics of lakes and their response to catchment processes. Within the catchment area, geological, land cover, and land use factors influence the composition of stream water that flows into the lake. These factors play a role in transporting various substances, both organic and inorganic, to the streams. Lakes act as dynamic filters, altering the chemical composition of water that flows through them. This study aims to investigate how a large, shallow lake impacts the quality of the river water as it passes through. It builds on an analysis of nutrient (carbon, nitrogen, phosphorus, silicon) fluxes into Lake Võrtsjärv, using six years of monthly monitoring data from five main inflows and the outflow. The research explores how catchment characteristics and hydrology affect nutrient concentrations and loadings into the lake, as well as the retention or release of substances by the lake. Findings reveal that catchment characteristics, such as land use and forest cover, significantly influence water quality parameters. Different inflows showed variations in water quality, and annual variations were observed, largely correlated with precipitation and discharge. Võrtsjärv plays a critical role in retaining or releasing nutrients, with varying impacts depending on the water budget of the lake. In years with a positive water balance, the lake retains all nutrients, whereas in dry years only inflowing N and P loads exceed their outflow. Overall, this study underscores the importance of lakes as integral components of catchment ecosystems, shedding light on their complex interactions with the environment and the implications for water quality. It emphasizes the need for careful consideration of land use and hydrological factors in managing and preserving these vital aquatic systems.

Chemical composition and ecogeochemical assessment of water in quarry lakes of the Zavitinskоyе and Ermakovskoye beryllium deposits (Russia)

The study presents the results of research on the chemical composition of water in quarry lakes of the lithium-beryllium Zavitinskоyе and fluorite-beryllium Ermakovskoye deposits located in the Eastern and Western Transbaikalia, respectively. Currently, the mines are abandoned, and the quarry lakes are actively used by the population of nearby villages for domestic and recreational purposes. It was found that the water in the quarries of these deposits is brackish and fresh, belonging to the sulfate-magnesium-calcium and hydrocarbonate-sulfate-magnesium-calcium types with a neutral and slightly alkaline reaction and high contents of sulfates and certain metals (Li, Be, Zn, Al, Mn, Fe, Sr, etc.). Significant variations in the concentrations of trace elements in the identified types of water indicate the significant role of the hydrogeochemical environment (pH, Eh, mineralization, etc.) in their dispersion or accumulation. The beryllium content in the water of Zavitinskоyе deposit quarries ranges from 0.35 to 10.1 μg/l, while in the Ermakovskoye quarry it ranges from 0.024 to 0.026 μg/l. The content of some regulated components in the water exceeds the maximum permissible concentrations established for fishery ponds and sanitary-hygienic norms by several orders of magnitude.

Hydrochemical characteristics of underground fluid observation wells in Shandong

To explore the hydrochemical characteristics of underground fluid observation wells in the Shandong area, piper diagram and Na-K-Mg triangle diagram methods were used to analyze the hydrochemical types and water-rock chemistry of water samples from 18 underground fluid observation wells in the study area. The results show that the hydrochemical types of underground fluid observation wells in the Shandong area are mainly SO4·Cl-Ca·Mg type, HCO3-Na type, HCO3-Ca·Mg type, and SO4·Cl-Na type. The chemical composition of water is mainly affected by water-rock interaction, rock salt dissolution, ion exchange, and human activities. Hydrogen and oxygen isotope analysis results show that atmospheric precipitation is the main recharge source of fluid wells in this area, and deep water recharge also plays an important role in some observation wells. The research results determine the hydrogeochemical background and well water source of underground fluid wells in the Shandong area and provide the scientific basis for fluid observation environment analysis, seismic monitoring and prediction, and seismic anomaly verification in the area.

Озера Турано-Уюкской котловины: эколого-гидрохимическое состояние и перспективы их бальнеологического использования

Abstract. Relevance. Currently, the creation of new institutions for the health improvement of the population within the Republic of Tuva on the basis of natural objects is a very urgent issue. Objectives. In this regard, we considered the hydrochemical composition of the lakes of the Turano-Uyuk depression, their ecological state and prospects for balneological use. Materials and methods. During field studies, employees of the TuvIKOPR SB RAS examined the largest natural lakes of the Turano-Uyuk depression and tested them to determine the chemical composition of natural waters. Chemical analysis was carried out in the Problem Research Laboratory of the National Tomsk Polytechnic University. In addition to field studies, a comparative literary method was used. Publications on this topic were studied and a retrospective analysis of the chemical composition of the waters of the lakes of the Turano-Uyuk depression and mud deposits as a therapeutic factor was carried out. Results. The greatest prospects for balneological development are Lake Beloye (White Lakes), the waters of which, according to the "Classification of mineral waters and therapeutic muds..." (MU No. 2000/34), belong to group 7, the therapeutic effect of which is determined by the amount of mineralization and ion-salt composition. Conclusions. The climatic conditions of the Turano-Uyuk basin, the presence of brackish (mineral) water and mineral mud (subject to the study of their balneological properties) open up prospects for organizing a resort, a health resort, a health resort on the shores of the lake, subject to the coordination of economic (balneological) activities with the Ministry of Forestry and Nature Management of the Republic of Tyva.

ОСОБЛИВОСТІ ХІМІЧНОГО СКЛАДУ ПІДЗЕМНИХ ВОД У ТЕРИГЕННИХ ВІДКЛАДАХ ЕОЦЕНУ ТА АЛЬБ-СЕНОМАНУ В БАСЕЙНІ ДНІПРА

Background. The Dniprovsko-Donetskyi Artesian Basin is the largest hydrogeological region of the first order in Ukraine in both area and resources. The main forecasted resources within its boundaries are confined to the Eocene aquifer and the Alb-Cenomanian aquifer complex. These aquifer and complex are the principal ones - they are the basis for centralized water supply of a number of large settlements, so studying their chemical composition is of exceptional importance. The parts of the mentioned aquifer and complex that contain drinking water are identified as groundwater bodies (GWBs) – groundwater monitoring objects for which environmental objectives and risks of failure to achieve these objectives should be determined. At the same time, the natural water quality composition of these groundwater bodies groups is characterized by significant spatial heterogeneity, which should be taken into account when determining trends in its changes and specifying environmental objectives. The aim of the study was to establish the peculiarities of the spatial distribution of water with different chemical composition. The object of the study was aquifers in Eocene and Alb-Cenomanian sediments within the Dniprovsko-Donetsky artesian basin (Dnipro River Basin), and the subject was the chemical composition of water in these aquifers. Methods. To achieve these purposes, data on the chemical composition of the aquifer in the Eocene sediments and the aquifer complex in the Alb-Cenomanian sediments were collected, summarized and analyzed from published and fund sources. The information was processed using geographic information systems, and a database was created to generate specialized maps and perform joint data analysis. Results. In the article the mineralization and macrocomponent composition of groundwater in the terrigenous sediments of the Eocene and Albian-Cenomanian of the Dnipro basin are investigated and the peculiarities of their spatial distribution are established. Particular attention is paid to the areas where the exploitation reserves of both groundwater aquifers are explored. The qualitative, including microcomponent, composition of groundwater in terrigenous sediments of the Eocene and Albian-Cenomanian in Chernigiv City was characterized in detail. Peculiarities of formation of the chemical composition of groundwater in terrigenous sediments of the Eocene and Albian-Cenomanian were established. Сonclusions. It has been established that despite the fact that both GWBs are located in the zone of active water exchange, the content of macro- and microcomponents in them is quite different. In particular, in the water in the Alb-Cenomanian sediments, the macrocomponent composition of water is more homogeneous, and the content of macro- and microcomponents is characterized by a smaller range of variation. The identified peculiarities of the natural quality composition of the studied GWBs should be taken into account in the process of groundwater monitoring, in particular, when specifying environmental objectives and determining the frequency of groundwater quality state observations.

Identification of Hydrochemical Characteristics, Spatial Evolution, and Driving Forces of River Water in Jinjiang Watershed, China

Rivers are an important source of water in humid regions, but their availability is greatly limited by water chemistry. In order to accurately identify the changes in river water chemical composition, the compositional analysis method (CoDA) is proposed from the perspective of compositional data analysis theory, which considers the geochemical riverine system as a whole and detects the compositional changes of the entire watershed. The basic data analysis is carried out by traditional analysis methods, and the results show that the hydrochemical characteristics of different sections of the basin have significant features. The water chemistry of Dongxi River is of the HCO3− Ca type. The water of the Xixi River shows a gradual evolution from the HCO3-Ca type and high SO42− content in the upper reaches to the Cl-Ca type in the lower reaches. The hydrochemistry of river water in the watershed is mainly affected by rock weathering leaching (PC1) and agricultural and domestic pollutant discharge (PC2), with a contribution rate of 48.4% and 19.7%, respectively. Rock weathering, mining, and agricultural pollution are the main factors affecting the chemical composition of river water in different regions. The spatial composition of a single sample at different scales is monitored by the Mahalanobis distance approach in an iterative manner to minimize the influence of a single anomaly on the composition center. The results show that the main reasons for the change in river water chemical composition along the Xixi River are attributed to mine pollution, domestic pollution, and tea plantation and that along the Dongxi River is caused by domestic pollution. The hydrochemical composition changes after the confluence of the Xixi River and Dongxi River are mainly affected by human activities and seawater in urban areas. This research could provide new perspectives and methods for detecting the influences of human and natural factors on the hydrochemistry of river water in humid regions worldwide.

Water quality of the southern Tibetan Plateau: hydrogeochemical assessment of the Yarlungzangbo River

The Yarlungzangbo River is the largest river system draining the northern slopes of the Himalayan ranges on the southern Tibetan Plateau and has a crucial role in the supply of water downstream. We investigated the chemical composition of the Yarlungzangbo River and its major tributaries (the Nianchu and Lhasa rivers). Water samples ( n = 165) were collected and analysed for major ions and trace elements. Multivariable analyses showed that the geology and climate are the major explanatory variables for the spatiotemporal variations of the water chemistry in this river system. The water chemistry is mainly controlled by carbonate weathering, with Ca 2+ and HCO 3 − as the dominant ions. Another potential ion source affecting the river water chemistry is the discharge from hot springs, which is rich in Na + , Cl − , SO 4 2− and Li, resulting in higher solute concentrations in the source region and upstream, with the total dissolved solids reaching 176.9 mg L −1 . The concentrations of most trace elements are generally low, although elevated concentrations of As (16.6 μ g L −1 ) and Sb (2.08 μ g L −1 ) are found in the headwaters and additions from untreated wastewater are evident. These concentrations exceed the national drinking water standard for China and the World Health Organization drinking water guideline, posing a risk to people living in both the local and surrounding areas. Supplementary material: The basic field records, water chemical compositions and trace elements of the Yarlungzangbo River and its main tributaries, and concentrations of chemicals of health significance as described by the international guideline (WHO) and the China national guideline (GB) for drinking water quality are available at https://doi.org/10.6084/m9.figshare.c.6850720

Unraveling the chemical fingerprint of the Miami River sources: Insights from high-resolution mass spectrometry and nontarget analysis

This study investigated the chemical composition of waters in the heavily urbanized and historically polluted Miami River, Florida. The goal was to assess the different water sources and anthropogenic influence in this managed area using nontarget analysis (NTA) combined with high-resolution mass spectrometry (HRMS). Surface water samples were collected from 10 sites during five sampling events in the wet season of 2021 and 2022. The HRMS data was processed using Compound Discoverer™ version 3.3, and the results were analyzed using techniques including Principal Component Analysis and Kendrick Mass Defect plots. Results showed a gradient change in the chemical composition from the Everglades to Biscayne Bay endmembers. The Seybold Canal, an adjacent canal, was consistently identified as a unique source of contaminants, contributing its own specific set of tracers. Increased presence and intensity of organic contaminants along the waterway was observed, indicating significant anthropogenic influence in the area. The NTA and post-processing were evaluated for reproducibility, demonstrating robustness with a 71.2% average reproducibility for compounds detected in 3 out of 5 sampling trips. A detection frequency of 80% (4 out of 5) was the set criterion for detected compounds suggested as tracers. To prioritize samples, hierarchical cluster analysis was employed, and potential tracers for each water source were determined. Tracers included natural products and agricultural herbicides and insecticides for the Everglades, anthropogenic contaminants for the Seybold Canal, and a lack of unique tracers for Biscayne Bay. Additionally, urban-influenced contaminants such as flame retardants, insect repellents, pharmaceuticals, and non-agricultural herbicides were identified along the river. This study highlights the impact of human activities on the Miami River and demonstrates the effectiveness of NTA in differentiating and tracking water sources. The results emphasize the importance of reproducibility in NTA and provide guidance on implementing monitoring strategies by prioritizing samples based on chemical compositions.

Perspectives from modern hydrology and hydrochemistry on a lacustrine biodiversity hotspot: Ancient Lake Poso, Central Sulawesi, Indonesia

The highly biodiverse Lake Poso, located in Central Sulawesi, Indonesia, can be considered one of the least studied ancient lakes in the world. Here, we present a comprehensive analysis of Lake Poso's hydrology and hydrochemistry, shedding light on factors that may have contributed to the exceptional biodiversity. Riverine and lake water chemical compositions indicated a soft water lake and relative major cation and anion abundances of Ca2+ ≫ Mg2+ > Na+ > K+ and HCO3– ≫ SO42− > Cl−, primarily a result of the high annual precipitation and chemical weathering of calcareous-siliceous metamorphic bedrock. Lake Poso’s nutrient concentrations were low (average DIN/TDP mass ratio of 6.2 and 50.9 for the lake surface water and its tributaries, respectively), indicating that most of the inlets were P-limited and that the lake was likely P-limited as well. Metal pollutants indicated a minor to moderate impact of anthropogenic land use (∼32 % of the catchment area). Water isotopic compositions of the different tributaries clearly delineated rivers draining higher elevation catchments with lower δ2H and δ18O from those draining lower elevation catchments with higher δ2H and δ18O. Surface lake water isotopic compositions indicated detectable evaporation from the lake leading toward more enriched isotope compositions than the integrated source signal. Overall, the findings suggested that Lake Poso remains relatively resilient to anthropogenic land use and related nutrient and pollutant inputs. However, ongoing alterations to its hydrological balance due to significant changes in land use may drive the lake towards higher trophic levels in the future.