To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrat...To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.展开更多
The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-ni...The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-nition as an eco-friendly solution for removing pollutants from various wastewater sources and are increasingly applied for micro-polluted water treatment.By reviewing 78 full-scale CW studies from Web of Science,it is summarized that the ranges of ammonium nitrogen(NH4+-N)concentrations in runoff,wastewater treatment plant effluent and polluted river were 0.1–6.6,0.3–12.3,and 0.2–41.1 mg/L,respectively.The ranges of ni-trate nitrogen concentrations were 0.2–14.2,0–5.7,and 0–2.6 mg/L,respectively.Removal efficiencies of CWs for micro-polluted water varied by CW types.The total nitrogen removal efficiencies for subsurface-flow CWs,free-water surface-flow CWs,and hybrid CWs ranged from 27.4%to 66.5%,16.8%to 89.8%,and 19.4%to 88.2%,respectively.The NH4+-N removal efficiencies ranged from 34.2%to 73.6%,38.4%to 89.4%and 13.5%to 94.2%,respectively.Additionally,other factors influencing contaminant removal efficiency such as hydraulic retention time,vegetation types,redox micro-environment and influent water quality were evaluated.Based on these findings,two strategies for improving the purification performance of CWs were proposed:the selection of incorporating electron donor substrates and the optimization of operation parameters.This paper serves as a synthesis of information to guide future research and full-scale CW applications in micro-polluted water treatment.展开更多
Unequal virtual water transfer may aggravate local water scarcity risk.However,the quantitative confirmation of a clear geographic convergence between virtual water transfer and water scarcity risk remains undetermine...Unequal virtual water transfer may aggravate local water scarcity risk.However,the quantitative confirmation of a clear geographic convergence between virtual water transfer and water scarcity risk remains undetermined.We present an analytical framework that reveals the spatial matching between global water scarcity risk and virtual water trade inequality.This framework integrates a three-dimensional water scarcity risk assessment,hybrid input-output analysis,pollution trade term construction,and geographic convergence identification.The framework is applied to 123 countries for long-term validation from 1991 to 2021.We show that despite global improvements in water efficiency and security,countries exceeding the maximum water vulnerability threshold have increased by 50%.South Asia is the largest net exporter of virtual water.Central Asia exhibits the most pronounced virtual water trade inequality.To achieve the same economic growth,Central Asia needs to pay several times the local water consumption costs of developed regions(15.9−83.6 times,2021).In the past 30 years,the average geographic convergence index exceeded 0.8.Countries facing severe water scarcity also exhibit pronounced inequalities in virtual water trade,indicating that a significant geographic convergence relationship exists.Effectively responding to this unsustainable relationship necessitates balancing both domestic resource risk management and global virtual water trade regulation.展开更多
Groundwater level(GWL)is a key indicator used to accurately assess groundwater resources and form the foundation for ef-fective groundwater management.This paper integrates a Gate Recurrent Unit(GRU)model with a Multi...Groundwater level(GWL)is a key indicator used to accurately assess groundwater resources and form the foundation for ef-fective groundwater management.This paper integrates a Gate Recurrent Unit(GRU)model with a Multi-head Self-attention mechan-ism(MSAM-GRU)to simulate GWLs in both confined and unconfined aquifers simultaneously.The model innovatively captures the lag times between GWLs in the unconfined aquifer and precipitation,as well as between GWLs in the confined aquifer and the upper aquifer.We have assessed the effectiveness of the proposed model using a case study in the Beijing Plain,China from January 2005 to December 2020.With the consideration of lag times,the results indicated that the MSAM-GRU model exhibits a maximum 67%and 73%reduction in RMSE compared to the Attention mechanism-GRU(AM-GRU)and GRU model,respectively.MSAM-GRU model exhibited a 31%reduction in RMSE and a 0.12 increase in R^(2) compared to the same model that do not account for lag time.In Region I,the shortest lag time of GWL in the unconfined aquifer was two months,while that in the confined aquifer was three months,indicating a longer delayed response in the confined aquifer.MSAM-GRU model considering lag time,was then applied to simulate the GWLs in the unconfined aquifer under different scenarios and to analyze whether GWL fluctuations affect subway operations.The simulation res-ults showed that under the scenario 1,the GWL in the unconfined aquifer would rise above the depth of subway station floor,threaten-ing the operation of subways.This study can provide reliable technical support for the accurate simulation of GWLs in multi-aquifer systems.展开更多
Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the i...Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the impacts of wildfire on hydrology have been widely assessed at the watershed scale,the underlying mechanisms of the responses of summer low flows remain poorly understood.In this study,we employed an integrated research framework that combines hydrometric monitoring with geochemical tracing to evaluate how the 2021 White Rock Lake Wildfire affected summer low flows,and to identify the underlying mechanisms governing these responses in the Okanagan Valley,British Columbia(BC),Canada.We found that(1)summer low flows,represented by Q90(flows exceeded at 90%of the time in summer)significantly increased following the wildfire(p<0.05);(2)summer low flows were primarily regulated by snow water in early summer(July),while dominated by groundwater in late summer(August and September);and(3)enhanced snow water contribution and reduced evapotranspiration(ET)were two primary contributors to the increased summer low flows.Our results provide insights for developing sustainable water management strategies for the region in the context of climate change and increasing forest disturbance.This study also demonstrates that the combination of hydrometric monitoring and geochemical tracing is an effective approach towards uncovering mechanisms that drive low-flow responses.展开更多
Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance com...Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance components have advanced,persistent biases remain due to the independent development of datasets,impacting basin scale water budget balance.In this research,we analyzed the mathematical origin of the bias between water budget components and developed a new basin-scale water balance calibration method that redistributes errors across components while enforcing water balance constraints.Validation confirms systematic improvements,with reduced RMSE(Precipitation:-2.29 mm/month;ET:-1.34 mm/month)and increased R2 against in situ observations.Applied to the Jinghe River Basin(2000−2019),the calibrated data reveal declining precipitation(-1.70 mm/year)and evapotranspiration(-1.84 mm/year)alongside slightly increasing runoff(0.20 mm/year in basin depth),signaling a drying trend.Land cover changes—marked by cropland loss(-3,497 km^(2))and forest(+720 km^(2))and grassland(+2,776 km^(2))expansion—reflect improved water consumption requirements by ecosystem,raising concerns for water retention and ecosystem stability.The method is particularly effective for ungauged basins with sparse ground data and underscores the need for integrated land-water management to enhance long-term resilience.展开更多
Phosphorus has been closely associated with eutrophication, a growing ecological problem globally. Because bacterial and algae responds to organic and inorganic nutrients differently, developing an accurate analytical...Phosphorus has been closely associated with eutrophication, a growing ecological problem globally. Because bacterial and algae responds to organic and inorganic nutrients differently, developing an accurate analytical method for the determination of dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) is critical for understanding eutrophication. This paper describes analytical variations observed in laboratory experiments for the determination of DIP and DOP. Several experimental parameters including phosphorus reagents’ temperature, water sample matrix, pH, and autoclave methods are investigated. With the optimization of the autoclave procedure, the recoveries of 8 model organic phosphorus compounds (i.e. adenosine-5-triphosphate di-sodium salt (ATP), phytic acid (PTA), sodium tripolyphosphate (STP), methyltriphenylphosphonium bromide (MPT), p-nitrophenyl phosphate magnesium salt (p-NPP), β-D-glucose-6-phosphate monosodium salt (G-6-P) and cocarboxylase (COCA)) are all well above 90% indicating significant analytical method improvement.展开更多
The kitchen-oil wastewater is characterized by a high concentration of organicmatter,complex composition and refractory pollutants,which make wastewater treatment more difficult.Based on the study of using micro-elect...The kitchen-oil wastewater is characterized by a high concentration of organicmatter,complex composition and refractory pollutants,which make wastewater treatment more difficult.Based on the study of using micro-electric field characteristic catalyst HCLL-S8-M to enhance the electron transfer between microorganisms in kitchen-oil wastewater which further improved the COD removal rate,we focus on themicrobial community,intracellular metabolism and extracellular respiration,and make an in-depth analysis of the molecular biological mechanisms to microbial treatment in wastewater.It is found that electroactive microorganisms are enriched on the material surface,and the expression levels of cytochrome c and riboflavin genes related to electron transfer are up-regulated,confirming that the surface micro-electric field structure could enhance the electron transfer between microbial species and improve the efficiency ofwastewater degradation.This study provides a new idea for the treatment of refractory organic wastewater.展开更多
High-dimensional data(a dataset with many features)were collected from 64 sampling sites to analyze the water quality in estuaries along the coast of the Bohai Sea,North China.The twenty-five water quality parameters ...High-dimensional data(a dataset with many features)were collected from 64 sampling sites to analyze the water quality in estuaries along the coast of the Bohai Sea,North China.The twenty-five water quality parameters analyzed were collected monthly from January 2021 to December 2021.Multivariate statistical techniques,such as the absolute principal component score-multiple linear regression model(APCS-MLR),correlation analysis,and analysis of variance were used to identify and quantify the potential sources or factors affecting water quality and to analyze the spatial-temporal variation in water quality.The water quality indices(WQIs),ranging from 67.96 to 70.67,showed that the water quality was at an intermediate level in the estuaries during both the flood and nonflood seasons.The concentrations of total phosphorus(TP),ammonia N(AN),and organic pollutants were greater in the Haihe River Basin than in the Liaohe River and Huanghe-Huaihe River Basins.The concentration of total nitrogen(TN)in the Haihe River Basin was lower than that in the Liaohe River and Huanghe-Huaihe River Basins.Heavy metal concentrations in the Liaohe River Basin were greater than those in the Haihe River and Huanghe-Huaihe River Basins.The annual mean concentrations of AN in the estuaries of the Haihe,Liaohe,and Huanghe(Yellow)rivers exhibited significant decreasing trends from 2013 to 2022,but no significant decreasing trends were found for permanganate index(COD_(Mn))or the TP.The concentrations of TN and AN were lower in the flood season than in the nonflood season,and the TP concentration was greater in the flood season than in the nonflood season.However,the concentrations of organic pollutants did not exhibit significant differences.Domestic sewage and industrial wastewater,substance exchange between air and water,nonpoint sources from rural and urban areas,and aquaculture wastewater were the major sources or factors responsible for water pollution in the estuaries.展开更多
The rapidly growing demand for lithium iron phosphate(LiFePO_(4))as the cathode material of lithium-ion batteries(LIBs)has aggravated the scarcity of phosphorus(P)reserves on Earth.This study introduces an environment...The rapidly growing demand for lithium iron phosphate(LiFePO_(4))as the cathode material of lithium-ion batteries(LIBs)has aggravated the scarcity of phosphorus(P)reserves on Earth.This study introduces an environmentally friendly and economical method of P recovery from municipal wastewater,providing the P source for LiFePO_(4) cathodes.The novel approach utilizes the sludge of Fe-coagulant-based chemical P removal(CPR)in wastewater treatment.After a sintering treatment with acid washing,the CPR sludge,enriched with P and Fe,transforms into purified P-Fe oxides(Fe2.1P1.0O5.6).These oxides can substitute up to 35%of the FePO_(4) reagent as precursor,producing a carbon-coated LiFePO_(4)(LiFePO_(4)/C)cathode with a specific discharge capacity of 114.9 mA·h·g^(-1)at current density of 17 mA·g^(-1)),and cycle stability of 99.2%after 100 cycles.The enhanced cycle performance of the as-prepared LiFePO_(4)/C cathode may be attributed to the incorporations of impurities(such as Ca^(2+)and Na^(+))from sludge,with improved stability of crystal structure.Unlike conventional P-fertilizers,this P recovery technology converts 100%of P in CPR sludge into the production of value-added LiFePO_(4)/C cathodes.The recovered P from municipal wastewater can meet up to 35%of the P demand in the Chinese LIBs industry,offering a cost-effective solution for addressing the pressing challenges of P scarcity.展开更多
Drains play an important role in seepage control in geotechnical engineering.The enormous number and one-dimensional(1D)geometry of drainage holes make their nature difficult to be accurately modeled in groundwater fl...Drains play an important role in seepage control in geotechnical engineering.The enormous number and one-dimensional(1D)geometry of drainage holes make their nature difficult to be accurately modeled in groundwater flow simulation.It has been well understood that drains function by presenting discharge boundaries,which can be characterized by water head,no-flux,unilateral or mixed water head-unilateral boundary condition.It has been found after years of practices that the flow simulation may become erroneous if the transitions among the drain boundary conditions are not properly considered.For this,a rigorous algorithm is proposed in this study to detect the onset of transitions among the water head,noflux and mixed water head-unilateral boundary conditions for downwards-drilled drainage holes,which theoretically completes the description of drain boundary conditions.After verification against a numerical example,the proposed algorithm is applied to numerical modeling of groundwater flow through a gravity dam foundation.The simulation shows that for hundreds of downwards-drilled drainage holes used to be prescribed with water head boundary condition,56%and 2%of them are transitioned to mixed water head-unilateral and no-flux boundary conditions,respectively.The phreatic surface around the drains will be overestimated by 25e33 m without the use of the mixed boundary condition.For the first time,this study underscores the importance of the mixed water head-unilateral boundary condition and the proposed transition algorithm in drain modeling,which may become more essential for simulation of transient flow because of groundwater dynamics.展开更多
Clarifying the mechanisms through which coal mining affects groundwater storage(GWS)variations is crucial for water resource conservation and sustainable development.The Ordos Mining Region in China,a key energy base ...Clarifying the mechanisms through which coal mining affects groundwater storage(GWS)variations is crucial for water resource conservation and sustainable development.The Ordos Mining Region in China,a key energy base in China with significant strategic importance,has undergone intensive coal mining activities that have substantially disrupted regional groundwater circulation.This study integrated data from the Gravity Recovery and Climate Experiment Satellite(GRACE)and Famine Early Warning Systems Network(FEWS NET)Land Data Assimilation System(FLDAS)models,combined with weighted downscaling methodology and water balance principles,to reconstruct high-resolution(0.01°)terrestrial water storage(TWS)and GWS changes in the Ordos Mining Region,China from April 2002 to December 2021.The accuracy of GWS variations were validated through pumping test measurements.Subsequently,Geodetector analysis was implemented to quantify the contributions of natural and anthropogenic factors to groundwater storage dynamics.Key findings include:1)TWS in the study area showed a fluctuating but overall decreasing trend,with a total reduction of 8901.11 mm during study period.The most significant annual decrease occurred in 2021,reaching 1696.77 mm.2)GWS exhibited an accelerated decline,with an average annual change rate of 44.35 mm/yr,totaling a decrease of 887.05 mm.The lowest annual groundwater storage level was recorded in 2020,reaching 185.69 mm.3)Precipitation(PRE)contributed the most to GWS variation(q=0.52),followed by coal mining water consumption(MWS)(q=0.41).The interaction between PRE and MWS exhibited a nonlinear enhancement effect on GWS changes(0.54).The synergistic effect of natural hydrological factors has a great influence on the change of GWS,but coal mining water consumption will continue to reduce GWS.These findings provide critical references for the management and regulation of groundwater resource in mining regions.展开更多
Arsenic-contaminated groundwater is widely used in agriculture.To meet the increasing demand for safe water in agriculture,an efficient and cost-effective method for As removal from groundwater is urgently needed.We h...Arsenic-contaminated groundwater is widely used in agriculture.To meet the increasing demand for safe water in agriculture,an efficient and cost-effective method for As removal from groundwater is urgently needed.We hypothesized that Fe(oxyhydr)oxide(FeOOH)minerals precipitated in situ from indigenous Fe in groundwater may immobilize As,providing a solution for safely using As-contaminated groundwater in irrigation.To confirm this hypothesis and identify the controlling mechanisms,we comprehensively evaluated the transport,speciation changes,and immobilization of As and Fe in agricultural canals irrigated using As-contaminated groundwater.The efficiently removed As and Fe in the canals accumulated in shallow sediment rather than subsurface sediment.Linear combination fitting(LCF)analysis of X-ray absorption near edge spectroscopy(XANES)indicated that As(Ⅴ)was the dominant As species,followed by As(Ⅲ),and therewas no FeAsO_(4) precipitate.Sequential extraction revealed higher contents of amorphous FeOOH and associated As in shallower sediment than in the subsurface layer.Stoichiometric molar ratio calculations,SEM-EDS,FTIR,and fluorescence spectroscopy collectively demonstrated that the microbial reductive dissolution of amorphous FeOOH proceeded via reactive dissolved organic matter(DOM)consumption in subsurface anoxic porewater environment facilitating high labile As,whereas in surface sediment,the in situ-generated amorphous FeOOH was stable and strongly inhibited As release via adsorption.In summary,groundwater Fe^(2+)can efficiently precipitate in benthic surface sediment as abundant amorphous FeOOH,which immobilizes most of the dissolved As,protecting agricultural soil from contamination.This field research supports the critical roles of the phase and reactivity of in situ-generated FeOOH in As immobilization and provides new insight into the sustainable use of contaminated water.展开更多
Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water sup...Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water supplement on tidal creek development and saltmarsh vegetation restoration,time series of high-resolution remote sensing images from2000 to 2021 were used to extract and analyze tidal creeks and saltmarsh vegetation in the Diaokou Estuary Reserve.The results are summarized as follows:(1)All tidal creek indices,except curvature,exhibited a significant linear increase with time,while curvature initially decreased and increased afterwards.The 5-year cumulative ecological water supplement volume was significantly positively correlated(R^(2)>0.7)with all tidal creek indices.(2)During the same period,most landscape pattern metrics of Phragmites australis increased,while those of Tamarix chinensis initially increased and then declined.Although the class area(CA)of Suaeda salsa increased with time,its perimeter-area fractal dimension(PAFRAC)and aggregation index(AI)fluctuated.(3)The CA of P.australis and S.salsa was significantly positively correlated with most tidal creek indices except curvature,while that of T.chinensis showed no significant correlation with any tidal creek index.Moreover,the AI and PAFRAC of P.australis were significantly positively correlated with fractal dimension,frequency/curvature of tidal creeks,respectively,while those of S.salsa and T.chinensis exhibited no significant correlation.In summary,the ecological water supplement project enhanced tidal creek development in coastal wetlands,promoting the restoration of P.australis and S.salsa,while having little impact on the restoration of T.chinensis.展开更多
Desert lakes are an important link in the water cycle and an important reservoir of water resources in arid and semi-arid areas,playing an important role in maintaining the stability of the regional natural environmen...Desert lakes are an important link in the water cycle and an important reservoir of water resources in arid and semi-arid areas,playing an important role in maintaining the stability of the regional natural environment.However,studies on the hydrochemical evolution and transformation relationships between desert lake groups and potential water sources are limited.Taking the Qixing Lake,the only lake group within the Hobq Desert in China,as the area of interest,this study collected samples of precipitation water,Yellow River water,lake water,and groundwater at different burial depths in the Qixing Lake region from July 2023 to October 2024.The hydrochemistry of different water bodies was analyzed using a combination of Piper diagrams,Gibbs diagrams,ratio of ions,and MixSIAR mixing models to reveal the transformational relationships of lake water with precipitation,groundwater,and Yellow River water.Results showed that both groundwater and surface water in the study area are weakly-to-strongly alkaline,with HCO_(3)–as the dominant anion and Na^(+),Ca^(2+),and K^(+) as the main cations.The hydrochemical type of groundwater and some lakes was dominated by HCO3–-Na+,whereas that of other lakes was dominated by Cl–-Na^(+)and HCO3–-Mg^(2+).The hydrochemistry of groundwater and Yellow River water in the Qixing Lake region was controlled mainly by a combination of evaporite saline and silicate rock mineral dissolution.The local meteoric water line(LMWL)of the study area proved that regional water bodies are strongly affected by evaporative fractionation.The MixSIAR model revealed that shallow groundwater is the main recharge source of the lake group in the Qixing Lake region,accounting for 59.0%–64.2%of the total.The findings can provide references for the identification of water sources in desert lakes and the development and utilization of water resources in desert lake regions.展开更多
In the context of climate change,the acceleration of the global water cycle has led to the emergence of abrupt transitions between drought and flood events,presenting a new challenge for flood and drought disaster mit...In the context of climate change,the acceleration of the global water cycle has led to the emergence of abrupt transitions between drought and flood events,presenting a new challenge for flood and drought disaster mitigation.Abrupt transitions between drought and flood refer to a phenomenon in which an extreme drought event quickly shifts to an extreme flood event,or vice versa,within a relatively short time span.This phenomenon disrupts the traditional spatiotemporal distribution patterns of water-related disasters,reflecting not only the extreme unevenness in the distribution of water resources but also the rapid alternation of the water cycle's evolution(He et al.,2016).Moreover,due to its suddenness,extremity,and complexity,it poses severe threats to human societies and ecosystems.Scientifically addressing abrupt transitions between drought and flood has thus become a new challenge in flood and drought disaster prevention.展开更多
The backwater effect caused by tributary inflow can significantly elevate the water level profile upstream of a confluence point.However,the influence of mainstream and confluence discharges on the backwater effect in...The backwater effect caused by tributary inflow can significantly elevate the water level profile upstream of a confluence point.However,the influence of mainstream and confluence discharges on the backwater effect in a river reach remains unclear.In this study,various hydrological data collected from the Jingjiang Reach of the Yangtze River in China were statistically analyzed to determine the backwater degree and range with three representative mainstream discharges.The results indicated that the backwater degree increased with mainstream discharge,and a positive relationship was observed between the runoff ratio and backwater degree at specific representative mainstream discharges.Following the operation of the Three Gorges Project,the backwater effect in the Jingjiang Reach diminished.For instance,mean backwater degrees for low,moderate,and high mainstream discharges were recorded as 0.83 m,1.61 m,and 2.41 m during the period from 1990 to 2002,whereas these values decreased to 0.30 m,0.95 m,and 2.08 m from 2009 to 2020.The backwater range extended upstream as mainstream discharge increased from 7000 m3/s to 30000 m3/s.Moreover,a random forest-based machine learning model was used to quantify the backwater effect with varying mainstream and confluence discharges,accounting for the impacts of mainstream discharge,confluence discharge,and channel degradation in the Jingjiang Reach.At the Jianli Hydrological Station,a decrease in mainstream discharge during flood seasons resulted in a 7%–15%increase in monthly mean backwater degree,while an increase in mainstream discharge during dry seasons led to a 1%–15%decrease in monthly mean backwater degree.Furthermore,increasing confluence discharge from Dongting Lake during June to July and September to November resulted in an 11%–42%increase in monthly mean backwater degree.Continuous channel degradation in the Jingjiang Reach contributed to a 6%–19%decrease in monthly mean backwater degree.Under the influence of these factors,the monthly mean backwater degree in 2017 varied from a decrease of 53%to an increase of 37%compared to corresponding values in 1991.展开更多
Developing a rapid and precise method for trace element analysis in geothermal water is crucial due to its high total dissolved solids and salinity,which can impact element determination.In this study,we optimized the...Developing a rapid and precise method for trace element analysis in geothermal water is crucial due to its high total dissolved solids and salinity,which can impact element determination.In this study,we optimized the determination of ferrum,manganese,strontium and barium in geothermal water samples collected from different regions.A matrix matching method was established for accurate quantification using Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES).Instrumental conditions and experimental parameters were optimized,and the influence of storage medium and storage duration on measurement accuracy were evaluated.The results demonstrated that storing geothermal water samples in 1%nitric acid had no significant impact on measurement results over an eight-week period.Calibration curve correlation coefficients exceeded 0.9998 for all target elements.The detection limits of this method ranged from 0.0002 mg/L to 0.0031 mg/L,with Relative Standard Deviations(RSD)were 0.07%–2.33%,and spike recovery rates were from 96.8%to 103.2%.The obtained data were consistent with results from the standard addition method and dilution method,demonstrating the reliability of this approach.This method offers low detection limits,high precision and excellent recovery rate,providing a robust reference for the accurate determination of ferrum,manganese,strontium and barium in geothermal water,thereby laying a solid foundation for the development and utilization of geothermal resources.展开更多
Safe operation of underground reservoirs in coal mines is crucial for the coordinated exploitation of coal and water resources in western China.Mine water infiltration significantly influences the stability of the coa...Safe operation of underground reservoirs in coal mines is crucial for the coordinated exploitation of coal and water resources in western China.Mine water infiltration significantly influences the stability of the coal pillar.Therefore,laboratory tests were systematically carried out on coal from the Daliuta Coal Mine in Northwest China.Samples were taken in the vertical and parallel bedding directions and soaked for 0 d,2 d,4 d,or 16 d.In this study,atomic absorption spectroscopy(AAS),X-ray diffraction(XRD),and scanning electron microscopy(SEM)were used to analyze the variations in the water absorption characteristics and corresponding internal structure of the coal.Uniaxial compression tests and synchronous acoustic emission(AE)monitoring revealed the sample failure process and mechanical properties of the samples.Finally,the time-and frequency-domain characteristics of the AE signal were comprehensively analyzed using fractal dimension,fast Fourier transform,and cluster analysis.The strength and elastic modulus demonstrate significant anisotropy with different bedding planes and reveal the existence of the optimum water content.Specifically,the sample strength increases after 2 d of immersion,with increments of 23.3% and 0.6% for the vertical and parallel bedding samples,and decreases after 16 d of immersion,with decreases of 29% and 45% for the vertical and parallel samples,respectively.Additionally,shear cracks account for over 60% during the damage development of the samples.The proportion of tensile cracks is higher for samples with longer immersion times and parallel bedding planes.This research provides a theoretical basis for stability evaluation and protection of coal pillars in underground reservoirs using the AE technique.展开更多
Runoff observation uncertainty is a key unsolved issue in the hydrology community.Existing studies mainly focused on observation uncertainty sources and their impacts on simulation performance,but the impacts on chang...Runoff observation uncertainty is a key unsolved issue in the hydrology community.Existing studies mainly focused on observation uncertainty sources and their impacts on simulation performance,but the impacts on changes of flow regime characteristics remained rare.This study detects temporal changes in 16 flow regime metrics from five main components(i.e.,magnitude,frequency of events,variability,duration,and timing),and evaluates the effects of observation uncertainty on trends of flow regime metrics by adopting a normal distribution error model and using uncertainty width,significant change rate of slopes,coefficient of variation,and degree of deviation.The daily runoff series from 1971 to 2020 at five hydrological stations(i.e.,Huangheyan,Tangnaihai,and Lanzhou in the Yellow River Source Region,Xianyang in the Weihe River Catchment,and Heishiguan in the Yiluo River Catchment)in the water conservation zone of Yellow River are collected for our study.Results showed that:(1)Flow regimes showed significant increases in the low flow magnitude,and significant decreases in the high and average flow magnitude,variability and duration at all the five stations.The magnitude,variability and duration metrics decreased significantly,and the frequency metrics increased significantly at Heishiguan.The low flow magnitude and timing metrics increased significantly,while the high flow magnitude,frequency and variability metrics decreased significantly at Xianyang.The low flow magnitude and high flow timing metrics increased significantly,while the low flow frequency,high flow magnitude and variability metrics decreased significantly in the Yellow River Source Region.(2)Observation uncertainty remarkably impacted the changes of 28.75% of total flow regime metrics at all the stations.The trends of 11.25% of total metrics changed from significance to insignificance,while those of 17.5% of total metrics changed from insignificance to significance.For the rest metrics,the trends remained the same,i.e.,significant(18.75%)and insignificant(52.50%)trends.(3)Observation uncertainty had the greatest impacts on the frequency metrics,especially at Xianyang,followed by duration,variability,timing and magnitude metrics.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFF1301301)the Natural Science Foundation of Xiamen Municipality(No.3502Z202472047)the Geological Survey Program of China Geological Survey(DD20190303).
文摘To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.
基金supported by the Natural Science Foundation of China(No.52470105)the Young Taishan Scholars Program of Shandong Province(No.358202103017).
文摘The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-nition as an eco-friendly solution for removing pollutants from various wastewater sources and are increasingly applied for micro-polluted water treatment.By reviewing 78 full-scale CW studies from Web of Science,it is summarized that the ranges of ammonium nitrogen(NH4+-N)concentrations in runoff,wastewater treatment plant effluent and polluted river were 0.1–6.6,0.3–12.3,and 0.2–41.1 mg/L,respectively.The ranges of ni-trate nitrogen concentrations were 0.2–14.2,0–5.7,and 0–2.6 mg/L,respectively.Removal efficiencies of CWs for micro-polluted water varied by CW types.The total nitrogen removal efficiencies for subsurface-flow CWs,free-water surface-flow CWs,and hybrid CWs ranged from 27.4%to 66.5%,16.8%to 89.8%,and 19.4%to 88.2%,respectively.The NH4+-N removal efficiencies ranged from 34.2%to 73.6%,38.4%to 89.4%and 13.5%to 94.2%,respectively.Additionally,other factors influencing contaminant removal efficiency such as hydraulic retention time,vegetation types,redox micro-environment and influent water quality were evaluated.Based on these findings,two strategies for improving the purification performance of CWs were proposed:the selection of incorporating electron donor substrates and the optimization of operation parameters.This paper serves as a synthesis of information to guide future research and full-scale CW applications in micro-polluted water treatment.
基金supported by National Natural Science Foundation of China(Grant No.52279027)National Key R&D Program of China(Grant No.2021YFC3200201)+1 种基金Key Research Project on Decision Consultation of the Strategic Development Department of China Association for Science and Technology(Grant No.2023070615CG111504)China Engineering Science and Technology Development Strategy Henan Research Institute Strategic Consulting Research Project(Grant No.2024HENYB01).
文摘Unequal virtual water transfer may aggravate local water scarcity risk.However,the quantitative confirmation of a clear geographic convergence between virtual water transfer and water scarcity risk remains undetermined.We present an analytical framework that reveals the spatial matching between global water scarcity risk and virtual water trade inequality.This framework integrates a three-dimensional water scarcity risk assessment,hybrid input-output analysis,pollution trade term construction,and geographic convergence identification.The framework is applied to 123 countries for long-term validation from 1991 to 2021.We show that despite global improvements in water efficiency and security,countries exceeding the maximum water vulnerability threshold have increased by 50%.South Asia is the largest net exporter of virtual water.Central Asia exhibits the most pronounced virtual water trade inequality.To achieve the same economic growth,Central Asia needs to pay several times the local water consumption costs of developed regions(15.9−83.6 times,2021).In the past 30 years,the average geographic convergence index exceeded 0.8.Countries facing severe water scarcity also exhibit pronounced inequalities in virtual water trade,indicating that a significant geographic convergence relationship exists.Effectively responding to this unsustainable relationship necessitates balancing both domestic resource risk management and global virtual water trade regulation.
基金Under the auspices of the National Key Research and Development Program of China(No.2024YFC3713102)。
文摘Groundwater level(GWL)is a key indicator used to accurately assess groundwater resources and form the foundation for ef-fective groundwater management.This paper integrates a Gate Recurrent Unit(GRU)model with a Multi-head Self-attention mechan-ism(MSAM-GRU)to simulate GWLs in both confined and unconfined aquifers simultaneously.The model innovatively captures the lag times between GWLs in the unconfined aquifer and precipitation,as well as between GWLs in the confined aquifer and the upper aquifer.We have assessed the effectiveness of the proposed model using a case study in the Beijing Plain,China from January 2005 to December 2020.With the consideration of lag times,the results indicated that the MSAM-GRU model exhibits a maximum 67%and 73%reduction in RMSE compared to the Attention mechanism-GRU(AM-GRU)and GRU model,respectively.MSAM-GRU model exhibited a 31%reduction in RMSE and a 0.12 increase in R^(2) compared to the same model that do not account for lag time.In Region I,the shortest lag time of GWL in the unconfined aquifer was two months,while that in the confined aquifer was three months,indicating a longer delayed response in the confined aquifer.MSAM-GRU model considering lag time,was then applied to simulate the GWLs in the unconfined aquifer under different scenarios and to analyze whether GWL fluctuations affect subway operations.The simulation res-ults showed that under the scenario 1,the GWL in the unconfined aquifer would rise above the depth of subway station floor,threaten-ing the operation of subways.This study can provide reliable technical support for the accurate simulation of GWLs in multi-aquifer systems.
基金the China Scholarship Council(CSC)the Uplifting Reciprocal Research Scholarship Program for sponsoring Shixuan Lyu+1 种基金supported by MITACS Accelerate(No.IT39116)the Okanagan Basin Water Board water conservation and quality improvement grant program。
文摘Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the impacts of wildfire on hydrology have been widely assessed at the watershed scale,the underlying mechanisms of the responses of summer low flows remain poorly understood.In this study,we employed an integrated research framework that combines hydrometric monitoring with geochemical tracing to evaluate how the 2021 White Rock Lake Wildfire affected summer low flows,and to identify the underlying mechanisms governing these responses in the Okanagan Valley,British Columbia(BC),Canada.We found that(1)summer low flows,represented by Q90(flows exceeded at 90%of the time in summer)significantly increased following the wildfire(p<0.05);(2)summer low flows were primarily regulated by snow water in early summer(July),while dominated by groundwater in late summer(August and September);and(3)enhanced snow water contribution and reduced evapotranspiration(ET)were two primary contributors to the increased summer low flows.Our results provide insights for developing sustainable water management strategies for the region in the context of climate change and increasing forest disturbance.This study also demonstrates that the combination of hydrometric monitoring and geochemical tracing is an effective approach towards uncovering mechanisms that drive low-flow responses.
基金supported by the National Key Research and Development Program of China(Grants No.2024YFF0810500 and 2022YFD1900802)the National Natural Scientific Foundations of China(Grants No.41991232,42301016 and 42571034)the Hainan Provincial Natural Science Foundation of China(Grant No.424QN354).
文摘Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance components have advanced,persistent biases remain due to the independent development of datasets,impacting basin scale water budget balance.In this research,we analyzed the mathematical origin of the bias between water budget components and developed a new basin-scale water balance calibration method that redistributes errors across components while enforcing water balance constraints.Validation confirms systematic improvements,with reduced RMSE(Precipitation:-2.29 mm/month;ET:-1.34 mm/month)and increased R2 against in situ observations.Applied to the Jinghe River Basin(2000−2019),the calibrated data reveal declining precipitation(-1.70 mm/year)and evapotranspiration(-1.84 mm/year)alongside slightly increasing runoff(0.20 mm/year in basin depth),signaling a drying trend.Land cover changes—marked by cropland loss(-3,497 km^(2))and forest(+720 km^(2))and grassland(+2,776 km^(2))expansion—reflect improved water consumption requirements by ecosystem,raising concerns for water retention and ecosystem stability.The method is particularly effective for ungauged basins with sparse ground data and underscores the need for integrated land-water management to enhance long-term resilience.
文摘Phosphorus has been closely associated with eutrophication, a growing ecological problem globally. Because bacterial and algae responds to organic and inorganic nutrients differently, developing an accurate analytical method for the determination of dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) is critical for understanding eutrophication. This paper describes analytical variations observed in laboratory experiments for the determination of DIP and DOP. Several experimental parameters including phosphorus reagents’ temperature, water sample matrix, pH, and autoclave methods are investigated. With the optimization of the autoclave procedure, the recoveries of 8 model organic phosphorus compounds (i.e. adenosine-5-triphosphate di-sodium salt (ATP), phytic acid (PTA), sodium tripolyphosphate (STP), methyltriphenylphosphonium bromide (MPT), p-nitrophenyl phosphate magnesium salt (p-NPP), β-D-glucose-6-phosphate monosodium salt (G-6-P) and cocarboxylase (COCA)) are all well above 90% indicating significant analytical method improvement.
基金supported by the National Natural Science Foundation of China(Nos.52150056 and 51838005)the Basic and Applied Basic Research Foundation of Guangdong Province(No.2023A1515111061).
文摘The kitchen-oil wastewater is characterized by a high concentration of organicmatter,complex composition and refractory pollutants,which make wastewater treatment more difficult.Based on the study of using micro-electric field characteristic catalyst HCLL-S8-M to enhance the electron transfer between microorganisms in kitchen-oil wastewater which further improved the COD removal rate,we focus on themicrobial community,intracellular metabolism and extracellular respiration,and make an in-depth analysis of the molecular biological mechanisms to microbial treatment in wastewater.It is found that electroactive microorganisms are enriched on the material surface,and the expression levels of cytochrome c and riboflavin genes related to electron transfer are up-regulated,confirming that the surface micro-electric field structure could enhance the electron transfer between microbial species and improve the efficiency ofwastewater degradation.This study provides a new idea for the treatment of refractory organic wastewater.
基金Supported by the National Natural Science Foundation of China(No.41571479)。
文摘High-dimensional data(a dataset with many features)were collected from 64 sampling sites to analyze the water quality in estuaries along the coast of the Bohai Sea,North China.The twenty-five water quality parameters analyzed were collected monthly from January 2021 to December 2021.Multivariate statistical techniques,such as the absolute principal component score-multiple linear regression model(APCS-MLR),correlation analysis,and analysis of variance were used to identify and quantify the potential sources or factors affecting water quality and to analyze the spatial-temporal variation in water quality.The water quality indices(WQIs),ranging from 67.96 to 70.67,showed that the water quality was at an intermediate level in the estuaries during both the flood and nonflood seasons.The concentrations of total phosphorus(TP),ammonia N(AN),and organic pollutants were greater in the Haihe River Basin than in the Liaohe River and Huanghe-Huaihe River Basins.The concentration of total nitrogen(TN)in the Haihe River Basin was lower than that in the Liaohe River and Huanghe-Huaihe River Basins.Heavy metal concentrations in the Liaohe River Basin were greater than those in the Haihe River and Huanghe-Huaihe River Basins.The annual mean concentrations of AN in the estuaries of the Haihe,Liaohe,and Huanghe(Yellow)rivers exhibited significant decreasing trends from 2013 to 2022,but no significant decreasing trends were found for permanganate index(COD_(Mn))or the TP.The concentrations of TN and AN were lower in the flood season than in the nonflood season,and the TP concentration was greater in the flood season than in the nonflood season.However,the concentrations of organic pollutants did not exhibit significant differences.Domestic sewage and industrial wastewater,substance exchange between air and water,nonpoint sources from rural and urban areas,and aquaculture wastewater were the major sources or factors responsible for water pollution in the estuaries.
基金supported by the National Natural Science Foundation of China(52100093,52270128,and 52261135627)the Guangdong Basic and Applied Basic Research Foundation(2023A1515011734 and 2021B1515120068)+2 种基金the Municipal Science and Technology Innovation Council of the Shen-zhen Government(KCXFZ20211020163556020 and SGDX20230116092359002)the Research Grants Council(17210219)the Innovation and Technology Fund(ITS/242/20FP)of the Hong Kong SAR Government。
文摘The rapidly growing demand for lithium iron phosphate(LiFePO_(4))as the cathode material of lithium-ion batteries(LIBs)has aggravated the scarcity of phosphorus(P)reserves on Earth.This study introduces an environmentally friendly and economical method of P recovery from municipal wastewater,providing the P source for LiFePO_(4) cathodes.The novel approach utilizes the sludge of Fe-coagulant-based chemical P removal(CPR)in wastewater treatment.After a sintering treatment with acid washing,the CPR sludge,enriched with P and Fe,transforms into purified P-Fe oxides(Fe2.1P1.0O5.6).These oxides can substitute up to 35%of the FePO_(4) reagent as precursor,producing a carbon-coated LiFePO_(4)(LiFePO_(4)/C)cathode with a specific discharge capacity of 114.9 mA·h·g^(-1)at current density of 17 mA·g^(-1)),and cycle stability of 99.2%after 100 cycles.The enhanced cycle performance of the as-prepared LiFePO_(4)/C cathode may be attributed to the incorporations of impurities(such as Ca^(2+)and Na^(+))from sludge,with improved stability of crystal structure.Unlike conventional P-fertilizers,this P recovery technology converts 100%of P in CPR sludge into the production of value-added LiFePO_(4)/C cathodes.The recovered P from municipal wastewater can meet up to 35%of the P demand in the Chinese LIBs industry,offering a cost-effective solution for addressing the pressing challenges of P scarcity.
基金Financial support from the National Natural Science Foundation of China(Grant Nos.51925906 and U2340228)the Natural Science Foundation of Hubei Province(Grant No.2022CFA028)is acknowledged.
文摘Drains play an important role in seepage control in geotechnical engineering.The enormous number and one-dimensional(1D)geometry of drainage holes make their nature difficult to be accurately modeled in groundwater flow simulation.It has been well understood that drains function by presenting discharge boundaries,which can be characterized by water head,no-flux,unilateral or mixed water head-unilateral boundary condition.It has been found after years of practices that the flow simulation may become erroneous if the transitions among the drain boundary conditions are not properly considered.For this,a rigorous algorithm is proposed in this study to detect the onset of transitions among the water head,noflux and mixed water head-unilateral boundary conditions for downwards-drilled drainage holes,which theoretically completes the description of drain boundary conditions.After verification against a numerical example,the proposed algorithm is applied to numerical modeling of groundwater flow through a gravity dam foundation.The simulation shows that for hundreds of downwards-drilled drainage holes used to be prescribed with water head boundary condition,56%and 2%of them are transitioned to mixed water head-unilateral and no-flux boundary conditions,respectively.The phreatic surface around the drains will be overestimated by 25e33 m without the use of the mixed boundary condition.For the first time,this study underscores the importance of the mixed water head-unilateral boundary condition and the proposed transition algorithm in drain modeling,which may become more essential for simulation of transient flow because of groundwater dynamics.
基金Under the National Key R&D Program Key Project(No.2021YFC3201201)National Natural Science Foundation of China(No.52360032)+2 种基金Basic Scientific Research Business Fee Project of Colleges And Universities Directly Under the Inner Mongolia Autonomous Region(No.JBYYWF2022001)Development Plan of Innovation Team of Colleges And Universities in Inner Mongolia Autonomous Region(No.NMGIRT2313)the Innovation Team of‘Grassland Talents’。
文摘Clarifying the mechanisms through which coal mining affects groundwater storage(GWS)variations is crucial for water resource conservation and sustainable development.The Ordos Mining Region in China,a key energy base in China with significant strategic importance,has undergone intensive coal mining activities that have substantially disrupted regional groundwater circulation.This study integrated data from the Gravity Recovery and Climate Experiment Satellite(GRACE)and Famine Early Warning Systems Network(FEWS NET)Land Data Assimilation System(FLDAS)models,combined with weighted downscaling methodology and water balance principles,to reconstruct high-resolution(0.01°)terrestrial water storage(TWS)and GWS changes in the Ordos Mining Region,China from April 2002 to December 2021.The accuracy of GWS variations were validated through pumping test measurements.Subsequently,Geodetector analysis was implemented to quantify the contributions of natural and anthropogenic factors to groundwater storage dynamics.Key findings include:1)TWS in the study area showed a fluctuating but overall decreasing trend,with a total reduction of 8901.11 mm during study period.The most significant annual decrease occurred in 2021,reaching 1696.77 mm.2)GWS exhibited an accelerated decline,with an average annual change rate of 44.35 mm/yr,totaling a decrease of 887.05 mm.The lowest annual groundwater storage level was recorded in 2020,reaching 185.69 mm.3)Precipitation(PRE)contributed the most to GWS variation(q=0.52),followed by coal mining water consumption(MWS)(q=0.41).The interaction between PRE and MWS exhibited a nonlinear enhancement effect on GWS changes(0.54).The synergistic effect of natural hydrological factors has a great influence on the change of GWS,but coal mining water consumption will continue to reduce GWS.These findings provide critical references for the management and regulation of groundwater resource in mining regions.
基金supported by the National Natural Science Foundation of China(Nos.41830753,42277201,42377242,and 41977286)the Scientific Research Foundation of Guangzhou University(No.YJ2023027)the College Student Innovation and Entrepreneurship Training Program(No.S202311078057).
文摘Arsenic-contaminated groundwater is widely used in agriculture.To meet the increasing demand for safe water in agriculture,an efficient and cost-effective method for As removal from groundwater is urgently needed.We hypothesized that Fe(oxyhydr)oxide(FeOOH)minerals precipitated in situ from indigenous Fe in groundwater may immobilize As,providing a solution for safely using As-contaminated groundwater in irrigation.To confirm this hypothesis and identify the controlling mechanisms,we comprehensively evaluated the transport,speciation changes,and immobilization of As and Fe in agricultural canals irrigated using As-contaminated groundwater.The efficiently removed As and Fe in the canals accumulated in shallow sediment rather than subsurface sediment.Linear combination fitting(LCF)analysis of X-ray absorption near edge spectroscopy(XANES)indicated that As(Ⅴ)was the dominant As species,followed by As(Ⅲ),and therewas no FeAsO_(4) precipitate.Sequential extraction revealed higher contents of amorphous FeOOH and associated As in shallower sediment than in the subsurface layer.Stoichiometric molar ratio calculations,SEM-EDS,FTIR,and fluorescence spectroscopy collectively demonstrated that the microbial reductive dissolution of amorphous FeOOH proceeded via reactive dissolved organic matter(DOM)consumption in subsurface anoxic porewater environment facilitating high labile As,whereas in surface sediment,the in situ-generated amorphous FeOOH was stable and strongly inhibited As release via adsorption.In summary,groundwater Fe^(2+)can efficiently precipitate in benthic surface sediment as abundant amorphous FeOOH,which immobilizes most of the dissolved As,protecting agricultural soil from contamination.This field research supports the critical roles of the phase and reactivity of in situ-generated FeOOH in As immobilization and provides new insight into the sustainable use of contaminated water.
基金National Key Research and Development Program of China,No.2022YFC3204302China National Admin-istration of Coal Geology,No.ZMKJ-2021-ZX04。
文摘Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water supplement on tidal creek development and saltmarsh vegetation restoration,time series of high-resolution remote sensing images from2000 to 2021 were used to extract and analyze tidal creeks and saltmarsh vegetation in the Diaokou Estuary Reserve.The results are summarized as follows:(1)All tidal creek indices,except curvature,exhibited a significant linear increase with time,while curvature initially decreased and increased afterwards.The 5-year cumulative ecological water supplement volume was significantly positively correlated(R^(2)>0.7)with all tidal creek indices.(2)During the same period,most landscape pattern metrics of Phragmites australis increased,while those of Tamarix chinensis initially increased and then declined.Although the class area(CA)of Suaeda salsa increased with time,its perimeter-area fractal dimension(PAFRAC)and aggregation index(AI)fluctuated.(3)The CA of P.australis and S.salsa was significantly positively correlated with most tidal creek indices except curvature,while that of T.chinensis showed no significant correlation with any tidal creek index.Moreover,the AI and PAFRAC of P.australis were significantly positively correlated with fractal dimension,frequency/curvature of tidal creeks,respectively,while those of S.salsa and T.chinensis exhibited no significant correlation.In summary,the ecological water supplement project enhanced tidal creek development in coastal wetlands,promoting the restoration of P.australis and S.salsa,while having little impact on the restoration of T.chinensis.
基金supported by the Inner Mongolia Autonomous Region"Unveiling the List of Commanders"Project(2024JBGS0019)the Inner Mongolia Autonomous Region Graduate Student Research Innovation Project(KC2024036B)+1 种基金the Innovative Team on Desertification Control and Sandy Area Resource Conservation and Utilization(BR241301)the Desert Sand Ecological Protection and Management Technology Innovation Team(NMGIRT2408).
文摘Desert lakes are an important link in the water cycle and an important reservoir of water resources in arid and semi-arid areas,playing an important role in maintaining the stability of the regional natural environment.However,studies on the hydrochemical evolution and transformation relationships between desert lake groups and potential water sources are limited.Taking the Qixing Lake,the only lake group within the Hobq Desert in China,as the area of interest,this study collected samples of precipitation water,Yellow River water,lake water,and groundwater at different burial depths in the Qixing Lake region from July 2023 to October 2024.The hydrochemistry of different water bodies was analyzed using a combination of Piper diagrams,Gibbs diagrams,ratio of ions,and MixSIAR mixing models to reveal the transformational relationships of lake water with precipitation,groundwater,and Yellow River water.Results showed that both groundwater and surface water in the study area are weakly-to-strongly alkaline,with HCO_(3)–as the dominant anion and Na^(+),Ca^(2+),and K^(+) as the main cations.The hydrochemical type of groundwater and some lakes was dominated by HCO3–-Na+,whereas that of other lakes was dominated by Cl–-Na^(+)and HCO3–-Mg^(2+).The hydrochemistry of groundwater and Yellow River water in the Qixing Lake region was controlled mainly by a combination of evaporite saline and silicate rock mineral dissolution.The local meteoric water line(LMWL)of the study area proved that regional water bodies are strongly affected by evaporative fractionation.The MixSIAR model revealed that shallow groundwater is the main recharge source of the lake group in the Qixing Lake region,accounting for 59.0%–64.2%of the total.The findings can provide references for the identification of water sources in desert lakes and the development and utilization of water resources in desert lake regions.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3209800)the National Natural Science Foundation of China(Grant No.52279011).
文摘In the context of climate change,the acceleration of the global water cycle has led to the emergence of abrupt transitions between drought and flood events,presenting a new challenge for flood and drought disaster mitigation.Abrupt transitions between drought and flood refer to a phenomenon in which an extreme drought event quickly shifts to an extreme flood event,or vice versa,within a relatively short time span.This phenomenon disrupts the traditional spatiotemporal distribution patterns of water-related disasters,reflecting not only the extreme unevenness in the distribution of water resources but also the rapid alternation of the water cycle's evolution(He et al.,2016).Moreover,due to its suddenness,extremity,and complexity,it poses severe threats to human societies and ecosystems.Scientifically addressing abrupt transitions between drought and flood has thus become a new challenge in flood and drought disaster prevention.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3209504)the National Natural Science Foundation of China(Grants No.U2040215 and 52479075)the Natural Science Foundation of Hubei Province(Grant No.2021CFA029).
文摘The backwater effect caused by tributary inflow can significantly elevate the water level profile upstream of a confluence point.However,the influence of mainstream and confluence discharges on the backwater effect in a river reach remains unclear.In this study,various hydrological data collected from the Jingjiang Reach of the Yangtze River in China were statistically analyzed to determine the backwater degree and range with three representative mainstream discharges.The results indicated that the backwater degree increased with mainstream discharge,and a positive relationship was observed between the runoff ratio and backwater degree at specific representative mainstream discharges.Following the operation of the Three Gorges Project,the backwater effect in the Jingjiang Reach diminished.For instance,mean backwater degrees for low,moderate,and high mainstream discharges were recorded as 0.83 m,1.61 m,and 2.41 m during the period from 1990 to 2002,whereas these values decreased to 0.30 m,0.95 m,and 2.08 m from 2009 to 2020.The backwater range extended upstream as mainstream discharge increased from 7000 m3/s to 30000 m3/s.Moreover,a random forest-based machine learning model was used to quantify the backwater effect with varying mainstream and confluence discharges,accounting for the impacts of mainstream discharge,confluence discharge,and channel degradation in the Jingjiang Reach.At the Jianli Hydrological Station,a decrease in mainstream discharge during flood seasons resulted in a 7%–15%increase in monthly mean backwater degree,while an increase in mainstream discharge during dry seasons led to a 1%–15%decrease in monthly mean backwater degree.Furthermore,increasing confluence discharge from Dongting Lake during June to July and September to November resulted in an 11%–42%increase in monthly mean backwater degree.Continuous channel degradation in the Jingjiang Reach contributed to a 6%–19%decrease in monthly mean backwater degree.Under the influence of these factors,the monthly mean backwater degree in 2017 varied from a decrease of 53%to an increase of 37%compared to corresponding values in 1991.
基金supported jointly by National Natural Science Foundation of China(NO.42430718)National Natural Science Foundation of China(NO.42077179)+2 种基金Natural Science Foundation of Fujian Province of China(NO.2023J01227)Natural Science Foundation of Xiamen,China(NO.3502Z20227309)Basic Scientific Research Business Expenses Project of the Chinese Academy of Geological Sciences(NO.YK202303).
文摘Developing a rapid and precise method for trace element analysis in geothermal water is crucial due to its high total dissolved solids and salinity,which can impact element determination.In this study,we optimized the determination of ferrum,manganese,strontium and barium in geothermal water samples collected from different regions.A matrix matching method was established for accurate quantification using Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES).Instrumental conditions and experimental parameters were optimized,and the influence of storage medium and storage duration on measurement accuracy were evaluated.The results demonstrated that storing geothermal water samples in 1%nitric acid had no significant impact on measurement results over an eight-week period.Calibration curve correlation coefficients exceeded 0.9998 for all target elements.The detection limits of this method ranged from 0.0002 mg/L to 0.0031 mg/L,with Relative Standard Deviations(RSD)were 0.07%–2.33%,and spike recovery rates were from 96.8%to 103.2%.The obtained data were consistent with results from the standard addition method and dilution method,demonstrating the reliability of this approach.This method offers low detection limits,high precision and excellent recovery rate,providing a robust reference for the accurate determination of ferrum,manganese,strontium and barium in geothermal water,thereby laying a solid foundation for the development and utilization of geothermal resources.
基金supported by the National Natural Science Foundation of China(Grant Nos.52174084 and U23B20146)the Open Fund for State Key Laboratory of Water Resource Protection and Utilization in Coal Mining(Grant No.WPUKFJJ2022-07)。
文摘Safe operation of underground reservoirs in coal mines is crucial for the coordinated exploitation of coal and water resources in western China.Mine water infiltration significantly influences the stability of the coal pillar.Therefore,laboratory tests were systematically carried out on coal from the Daliuta Coal Mine in Northwest China.Samples were taken in the vertical and parallel bedding directions and soaked for 0 d,2 d,4 d,or 16 d.In this study,atomic absorption spectroscopy(AAS),X-ray diffraction(XRD),and scanning electron microscopy(SEM)were used to analyze the variations in the water absorption characteristics and corresponding internal structure of the coal.Uniaxial compression tests and synchronous acoustic emission(AE)monitoring revealed the sample failure process and mechanical properties of the samples.Finally,the time-and frequency-domain characteristics of the AE signal were comprehensively analyzed using fractal dimension,fast Fourier transform,and cluster analysis.The strength and elastic modulus demonstrate significant anisotropy with different bedding planes and reveal the existence of the optimum water content.Specifically,the sample strength increases after 2 d of immersion,with increments of 23.3% and 0.6% for the vertical and parallel bedding samples,and decreases after 16 d of immersion,with decreases of 29% and 45% for the vertical and parallel samples,respectively.Additionally,shear cracks account for over 60% during the damage development of the samples.The proportion of tensile cracks is higher for samples with longer immersion times and parallel bedding planes.This research provides a theoretical basis for stability evaluation and protection of coal pillars in underground reservoirs using the AE technique.
基金National Key Research and Development Program of China,No.2021YFC3201102National Natural Science Foundation of China,No.42071041,No.42171047。
文摘Runoff observation uncertainty is a key unsolved issue in the hydrology community.Existing studies mainly focused on observation uncertainty sources and their impacts on simulation performance,but the impacts on changes of flow regime characteristics remained rare.This study detects temporal changes in 16 flow regime metrics from five main components(i.e.,magnitude,frequency of events,variability,duration,and timing),and evaluates the effects of observation uncertainty on trends of flow regime metrics by adopting a normal distribution error model and using uncertainty width,significant change rate of slopes,coefficient of variation,and degree of deviation.The daily runoff series from 1971 to 2020 at five hydrological stations(i.e.,Huangheyan,Tangnaihai,and Lanzhou in the Yellow River Source Region,Xianyang in the Weihe River Catchment,and Heishiguan in the Yiluo River Catchment)in the water conservation zone of Yellow River are collected for our study.Results showed that:(1)Flow regimes showed significant increases in the low flow magnitude,and significant decreases in the high and average flow magnitude,variability and duration at all the five stations.The magnitude,variability and duration metrics decreased significantly,and the frequency metrics increased significantly at Heishiguan.The low flow magnitude and timing metrics increased significantly,while the high flow magnitude,frequency and variability metrics decreased significantly at Xianyang.The low flow magnitude and high flow timing metrics increased significantly,while the low flow frequency,high flow magnitude and variability metrics decreased significantly in the Yellow River Source Region.(2)Observation uncertainty remarkably impacted the changes of 28.75% of total flow regime metrics at all the stations.The trends of 11.25% of total metrics changed from significance to insignificance,while those of 17.5% of total metrics changed from insignificance to significance.For the rest metrics,the trends remained the same,i.e.,significant(18.75%)and insignificant(52.50%)trends.(3)Observation uncertainty had the greatest impacts on the frequency metrics,especially at Xianyang,followed by duration,variability,timing and magnitude metrics.
