Rivers are essential for water supply,agriculture,hydropower,and biodiversity,yet they face increasing threats from climate change and pollution globally.The Koshi River Basin,spanning China,Nepal,and India,is a trans...Rivers are essential for water supply,agriculture,hydropower,and biodiversity,yet they face increasing threats from climate change and pollution globally.The Koshi River Basin,spanning China,Nepal,and India,is a transboundary basin that includes glacier-fed headwaters and densely populated downstream regions.This study investigates the hydrogeochemistry and water quality dynamics of the basin,focusing on seasonal and spatial variations and their implications for drinking and irrigation suitability.A total of 117 water samples from different segments of the basin were analyzed across premonsoon,monsoon,and post-monsoon seasons using in-situ,laboratory tests,and multivariate statistical methods.The results indicated that carbonate and silicate weathering were the dominant sources of solutes in the study region,with Ca^(2+)and HCO_(3)^(-)being the major ionic constituents.Seasonal variations revealed higher ionic concentrations in pre-and postmonsoon periods due to increased mineralization,while monsoonal dilution significantly reduced solute loads.Spatially,the higher hydrogeochemistry index in the upstream and lower values in downstream tributaries indicate intensive weathering in the headwaters but are further diluted by melting water and precipitation downstream.Inversely,higher pollution risks only appeared in downstream areas,where NO_(3)^(-)suggested agricultural runoff and wastewater intrusion.Water quality index<50 classified most river segments as suitable for drinking,while sodium adsorption ratio<1 confirmed irrigation suitability,except in some segments of the downstream zones with higher anthropogenic influence based on major ions.This study also supports Sustainable Development Goal 6(clean water and sanitation),13(climate action),and 15(life on land)by providing critical insights into water quality dynamics and informing sustainable water management strategies applicable to other glacier-fed river basins worldwide.展开更多
Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aqu...Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aquatic evaporation-crystallization,and the input of precipitation-derived materials into river basins.A total of 208 water samples were collected between August 2021 and August 2022 to investigate the hydrochemical characteristics and their influencing factors of the surface water and the groundwater in the Mingyong River Basin.To systematically analyze the data,we combined hydrogeochemical and statistical methods:descriptive statistics characterized ion concentration and physicochemical parameter distributions;Piper trilinear diagrams classified hydrochemical types;Pearson correlation analysis assessed ion-ion and ionTDS dependencies;Gibbs diagrams and ion ratio analysis identified solute sources;and the absolute principal component score-multiple linear regression(APCS-MLR)model quantified the contribution rates of different influencing factors.The results revealed that the dominant cations in the surface water and groundwater are Ca^(2+)and Mg^(2+),while the dominant anions are HCO_(3)^(-)and SO_(4)^(2-).The groundwater exhibits an extended residence time within rock strata,facilitating prolonged interaction with soluble minerals and intensifying the water-rock reaction process,thereby resulting in higher levels of electrical conductivity(EC),pH,and total dissolved solids(TDS)than those in the surface water.Secondly,the parameters of the surface water and groundwater indicate positive correlation.The weathering of rocks constitutes the primary solute source in the water of the basin.The hydrochemical composition of the basin water is primarily influenced by both carbonate and silicate rocks,with a minor contribution from evaporite rocks.The water bodies in the basin are affected by anthropogenic activities.The surface water is influenced by four sources,namely lixiviation-enrich,human activities,geological environmental,and unknown sources.The groundwater is influenced by five sources,namely lixiviation-enrich,primary geological,human activities,geological environmental,and unknown sources.展开更多
While oceanic and coastal acidification has gained increased attention,long-term pH trends and their drivers in large freshwater systems remain poorly understood.The Laurentian Great Lakes are the world’s largest fre...While oceanic and coastal acidification has gained increased attention,long-term pH trends and their drivers in large freshwater systems remain poorly understood.The Laurentian Great Lakes are the world’s largest freshwater system,and in many ways resemble marine ecosystems.However,unlike the open ocean and coastal waters where pH has declined due to rising atmospheric CO_(2),no significant pH trends have been observed in the Laurentian Great Lakes,despite significant ecosystem changes driven partly by the invasion of dreissenid mussels.This study examined 41 years of field observations from Lake Michigan to investigate the long-term carbonate chemistry dynamics.Observational results revealed substantial declines in both total alkalinity(TA)and dissolved inorganic carbon(DIC)over the four decades.Mussel shell calcification emerged as the primary mechanism behind these declines,accounting for 97%and 47%of the observed changes in TA and DIC,respectively,lowering water column pH by 0.24 units.Elevated carbon accumulation in soft mussel tissues,coupled with long-term changes in the air-water pCO_(2)gradient during summer,significantly contributed to long-term DIC variations,explaining 18%and 28%of the lake-wide DIC loss.These two mechanisms also resulted in an overall pH increase of 0.09 and 0.12 units,largely offsetting the calcification-driven pH decrease.These findings bridge a gap in acidification research for large freshwater systems and provide valuable insights for comprehensive lake-wide management strategies.展开更多
Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-me...Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.展开更多
Understanding the hydrochemical dynamics of alpine arid basins is essential for ensuring sustainable water resources on the Tibetan Plateau.The Nianchu River,a typical alpine and arid basin on the Tibetan Plateau,is t...Understanding the hydrochemical dynamics of alpine arid basins is essential for ensuring sustainable water resources on the Tibetan Plateau.The Nianchu River,a typical alpine and arid basin on the Tibetan Plateau,is the focal area of the“One River,Two Tributaries”Comprehensive Development Project in Xizang Autonomous Region of China.However,no systematic studies on hydrochemistry in this basin have been conducted.This study investigated the spatio-temporal variations and controlling mechanisms of water chemistry in the Nianchu River basin with a focus on the understudied influence of widely distributed geothermal springs.During the dry and wet seasons,44 river water and 13 geothermal water samples were collected and analyzed for major ions.Results showed that the river water was weakly alkaline,with total dissolved solids and major ion concentrations(e.g.,Ca^(2+),HCO₃^(-),SO_(4)^(2-))significantly higher in the dry season(mean EC:372μS/cm)than in the wet season(mean EC:236μS/cm),and peaking in the midstream tributary of the Longma River.In contrast,the geothermal springs were moderately acidic and exhibited markedly higher mineralization(mean EC:1,936μS/cm),with Na^(+),K^(+),and Cl^(-)concentrations being 20.8,22.5,and 44.8 times those in river water,respectively.The direct discharge of geothermal water was identified as a key driver that significantly elevated Na^(+),K^(+),and Cl^(-)levels and altered the hydrochemical facies of the river in affected reaches.The main conclusions are that:(1)the hydrochemical evolution of the Nianchu River is predominantly governed by carbonate and silicate weathering,while geothermal water chemistry is controlled by evaporation-crystallization and deep water-rock interactions;and(2)sulfuric acid participates in carbonate weathering alongside carbonic acid,particularly in the mid-lower reaches,enhances the release of Ca^(2+),Mg^(2+),and SO_(4)^(2-).This study provides a holistic understanding of hydrogeochemical controls in a typical alpine basin and underscores the critical role of geothermal fluids,offering a scientific basis for protecting water resources under climate and anthropogenic pressures.展开更多
基金financially supported by the CASANSO Sustainable Development Research Project(Grant No.CAS-ANSO-SDRP-2024-05)the Research Directorate,Rector’s Office Tribhuvan University,Nepal(TU-NPAR-079/80-ERG-08)。
文摘Rivers are essential for water supply,agriculture,hydropower,and biodiversity,yet they face increasing threats from climate change and pollution globally.The Koshi River Basin,spanning China,Nepal,and India,is a transboundary basin that includes glacier-fed headwaters and densely populated downstream regions.This study investigates the hydrogeochemistry and water quality dynamics of the basin,focusing on seasonal and spatial variations and their implications for drinking and irrigation suitability.A total of 117 water samples from different segments of the basin were analyzed across premonsoon,monsoon,and post-monsoon seasons using in-situ,laboratory tests,and multivariate statistical methods.The results indicated that carbonate and silicate weathering were the dominant sources of solutes in the study region,with Ca^(2+)and HCO_(3)^(-)being the major ionic constituents.Seasonal variations revealed higher ionic concentrations in pre-and postmonsoon periods due to increased mineralization,while monsoonal dilution significantly reduced solute loads.Spatially,the higher hydrogeochemistry index in the upstream and lower values in downstream tributaries indicate intensive weathering in the headwaters but are further diluted by melting water and precipitation downstream.Inversely,higher pollution risks only appeared in downstream areas,where NO_(3)^(-)suggested agricultural runoff and wastewater intrusion.Water quality index<50 classified most river segments as suitable for drinking,while sodium adsorption ratio<1 confirmed irrigation suitability,except in some segments of the downstream zones with higher anthropogenic influence based on major ions.This study also supports Sustainable Development Goal 6(clean water and sanitation),13(climate action),and 15(life on land)by providing critical insights into water quality dynamics and informing sustainable water management strategies applicable to other glacier-fed river basins worldwide.
基金funded by the National Natural Science Foundation of China(No.42061012)the Open Project of Yunnan Province’s First Class Discipline of Soil and Water Conservation and Desertification Control(SBK20240019)。
文摘Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aquatic evaporation-crystallization,and the input of precipitation-derived materials into river basins.A total of 208 water samples were collected between August 2021 and August 2022 to investigate the hydrochemical characteristics and their influencing factors of the surface water and the groundwater in the Mingyong River Basin.To systematically analyze the data,we combined hydrogeochemical and statistical methods:descriptive statistics characterized ion concentration and physicochemical parameter distributions;Piper trilinear diagrams classified hydrochemical types;Pearson correlation analysis assessed ion-ion and ionTDS dependencies;Gibbs diagrams and ion ratio analysis identified solute sources;and the absolute principal component score-multiple linear regression(APCS-MLR)model quantified the contribution rates of different influencing factors.The results revealed that the dominant cations in the surface water and groundwater are Ca^(2+)and Mg^(2+),while the dominant anions are HCO_(3)^(-)and SO_(4)^(2-).The groundwater exhibits an extended residence time within rock strata,facilitating prolonged interaction with soluble minerals and intensifying the water-rock reaction process,thereby resulting in higher levels of electrical conductivity(EC),pH,and total dissolved solids(TDS)than those in the surface water.Secondly,the parameters of the surface water and groundwater indicate positive correlation.The weathering of rocks constitutes the primary solute source in the water of the basin.The hydrochemical composition of the basin water is primarily influenced by both carbonate and silicate rocks,with a minor contribution from evaporite rocks.The water bodies in the basin are affected by anthropogenic activities.The surface water is influenced by four sources,namely lixiviation-enrich,human activities,geological environmental,and unknown sources.The groundwater is influenced by five sources,namely lixiviation-enrich,primary geological,human activities,geological environmental,and unknown sources.
基金Supported by the National Natural Science Foundation of China(No.43277051)the Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education(No.B230203006).
文摘While oceanic and coastal acidification has gained increased attention,long-term pH trends and their drivers in large freshwater systems remain poorly understood.The Laurentian Great Lakes are the world’s largest freshwater system,and in many ways resemble marine ecosystems.However,unlike the open ocean and coastal waters where pH has declined due to rising atmospheric CO_(2),no significant pH trends have been observed in the Laurentian Great Lakes,despite significant ecosystem changes driven partly by the invasion of dreissenid mussels.This study examined 41 years of field observations from Lake Michigan to investigate the long-term carbonate chemistry dynamics.Observational results revealed substantial declines in both total alkalinity(TA)and dissolved inorganic carbon(DIC)over the four decades.Mussel shell calcification emerged as the primary mechanism behind these declines,accounting for 97%and 47%of the observed changes in TA and DIC,respectively,lowering water column pH by 0.24 units.Elevated carbon accumulation in soft mussel tissues,coupled with long-term changes in the air-water pCO_(2)gradient during summer,significantly contributed to long-term DIC variations,explaining 18%and 28%of the lake-wide DIC loss.These two mechanisms also resulted in an overall pH increase of 0.09 and 0.12 units,largely offsetting the calcification-driven pH decrease.These findings bridge a gap in acidification research for large freshwater systems and provide valuable insights for comprehensive lake-wide management strategies.
基金supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515110824 and 2025A1515011839)Shenzhen Science and Technology Program(No.RCBS20231211090638066).
文摘Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.
基金jointly funded by the School Scientific Research Development Fund project(2022LFR091)。
文摘Understanding the hydrochemical dynamics of alpine arid basins is essential for ensuring sustainable water resources on the Tibetan Plateau.The Nianchu River,a typical alpine and arid basin on the Tibetan Plateau,is the focal area of the“One River,Two Tributaries”Comprehensive Development Project in Xizang Autonomous Region of China.However,no systematic studies on hydrochemistry in this basin have been conducted.This study investigated the spatio-temporal variations and controlling mechanisms of water chemistry in the Nianchu River basin with a focus on the understudied influence of widely distributed geothermal springs.During the dry and wet seasons,44 river water and 13 geothermal water samples were collected and analyzed for major ions.Results showed that the river water was weakly alkaline,with total dissolved solids and major ion concentrations(e.g.,Ca^(2+),HCO₃^(-),SO_(4)^(2-))significantly higher in the dry season(mean EC:372μS/cm)than in the wet season(mean EC:236μS/cm),and peaking in the midstream tributary of the Longma River.In contrast,the geothermal springs were moderately acidic and exhibited markedly higher mineralization(mean EC:1,936μS/cm),with Na^(+),K^(+),and Cl^(-)concentrations being 20.8,22.5,and 44.8 times those in river water,respectively.The direct discharge of geothermal water was identified as a key driver that significantly elevated Na^(+),K^(+),and Cl^(-)levels and altered the hydrochemical facies of the river in affected reaches.The main conclusions are that:(1)the hydrochemical evolution of the Nianchu River is predominantly governed by carbonate and silicate weathering,while geothermal water chemistry is controlled by evaporation-crystallization and deep water-rock interactions;and(2)sulfuric acid participates in carbonate weathering alongside carbonic acid,particularly in the mid-lower reaches,enhances the release of Ca^(2+),Mg^(2+),and SO_(4)^(2-).This study provides a holistic understanding of hydrogeochemical controls in a typical alpine basin and underscores the critical role of geothermal fluids,offering a scientific basis for protecting water resources under climate and anthropogenic pressures.
