Water Sources Research Articles

Isotopic steady state or non-steady state transpiration? Insights from whole tree chambers.

Unravelling the complexities of transpiration can be assisted by understanding the oxygen isotope composition of transpired water vapour (δE). It is often assumed that δE is at steady state, thereby mirroring the oxygen isotope composition of source water (δsource), but this assumption has never been tested at the whole-tree scale. This study utilised the unique infrastructure of 12 whole-tree chambers (WTC) enclosing Eucalyptus parramattensis trees to measure δE along with concurrent temperature and gas exchange data. Six chambers tracked ambient air temperature and six were exposed to an ambient +3°C warming treatment. Day-time means for δE were within 1.2‰ of δsource (-3.3‰) but varied considerably throughout the day. Our observations show that Eucalyptus parramattensis trees are seldom transpiring at isotopic steady state over a diel period, but transpiration approaches source water isotopic composition over longer time periods.

Hydro-geochemistry and age-dependent health risk assessment of nitrate, nitrite, and fluoride in health facilities water: a multivariate analysis.

Groundwater from alluvial fan plains is the prevailing water source, especially for arid/semiarid regions, but its contamination poses substantial risks to water supply and public health. The recent study aims to assess the hydro-geochemistry, distribution, and potential health risks of NO3-, NO2-, and F- concentrations in the groundwater of previously unexplored health facilities in District Vehari, Punjab, Pakistan. In total, 75 groundwater samples were evaluated for NO3-, NO2-, and F- levels as well as pH, EC, TDS, CO32-, HCO3-, Cl-, Na+, Fe, K+, Ca2+, Mg2+, taste, odor, color, and turbidity. The Durav graph shows that the water type is Na-HCO3-Ca, with Na and HCO3 dominant, weak acids > strong acids, and alkaline ions > alkalis. Results revealed that drinking water samples (21.73% and 20%) taken from Tehsil Mailsi, and the Basic Health Unit (BHU) exceeded the WHO standard (1.5mg/L) for F- concentration, respectively. Moreover, the mean chronic daily intake (CDI) of F- was 0.044, 0.018, and 0.02mg/kg/day in children, men, and women, respectively. Similarly, the average CDI of NO3- was 0.113, 0.046, and 0.050 in children, men, and women, respectively, and the respective values of NO2- were 0.004, 0.001, and 0.001. The NO2- shows a significant range of hazard quotient (HQ) (0.0-1.172) in children. The range of HQ for F- was 0.0-3.114, 0.0-1.290, and 0.0-1.389 in children, men, and women, respectively. Additionally, the health risks analysis revealed an HQ > 1.0 for children in groundwater, indicating a potential carcinogenic risk from the F-. Pearson correlation and PCA analysis found a significant positive correlation (0.8) between NO3- and NO2- and a negative correlation (0.3) between F- and HCO3-. These findings highlight the need for groundwater treatment in healthcare facilities prior to water consumption. Enforcing international and national drinking water standards in healthcare units is vital to strengthening services and providing equitable access to safe drinking water. Legislative and efficient water management measures must be taken for the protection of public health.

Profiling the endocrine disrupting properties of triazines, triazoles and short-chain PFAS.

Persistent, mobile and toxic (PMT) compounds released to the environment are likely to pollute drinking water sources due to their slow environmental degradation (persistency) and high water solubility (mobility). The aim of the present study was to create in vitro hazard profiles for sixteen triazoles, nine triazines and eleven PFAS based on their agonistic and antagonistic effects in estrogen receptor (ER), androgen receptor (AR) and thyroid hormone receptor (TR) reporter gene assays, their ability to bind human transthyretin (TTR), and their effects on steroidogenesis. The triazole fungicides tetraconazole, bitertanol, fenbuconazole, tebuconazole, cyproconazole, difenoconazole, propiconazole, paclobutrazol and triadimenol had agonistic or antagonistic effects on the ER and AR. Difenoconazole, propiconazole and triadimenol were also found to be TR antagonists. The triazine herbicide ametryn was an ER, AR and TR antagonist. The same nine triazole fungicides and the triazines atrazine, deethyl-atrazine and ametryn affected the secretion of steroid hormones. Furthermore, PFAS compounds PFBS, PFHxS, PFHxA, PFOS, PFOA and GenX and the triazoles bitertanol, difenoconazole and 4-methyl benzotriazole were found to displace T4 from TTR. These results are in line with earlier in vitro and in vivo studies on the endocrine disrupting properties of triazines, triazoles and PFAS. The present study demonstrates that this battery of in vitro bioassays can be used to profile compounds from different classes based on their endocrine disrupting properties as a first step to prioritize them for further research, emission reduction, environmental remediation and regulatory purposes.

Archetypes of Spatial Concentration Variability of Organic Contaminants in the Atmosphere: Implications for Identifying Sources and Mapping the Gaseous Outdoor Inhalation Exposome.

Whereas inhalation exposure to organic contaminants can negatively impact human health, knowledge of their spatial variability in the ambient atmosphere remains limited. We analyzed the extracts of passive air samplers deployed at 119 unique sites in Southern Canada between 2019 and 2022 for 353 organic vapors. Hierarchical clustering of the obtained data set revealed four archetypes of spatial concentration variability in the outdoor atmosphere, which are indicative of common sources and similar atmospheric dispersion behavior. "Point Source" signatures are characterized by elevated concentration in the vicinity of major release locations. A "Population" signature applies to compounds whose air concentrations are highly correlated with population density, and is associated with emissions from consumer products. The "Water Source" signature applies to substances with elevated levels in the vicinity of water bodies from which they evaporate. Another group of compounds displays a "Uniform" signature, indicative of a lack of major sources within the study area. We illustrate how such a data set, and the derived spatial patterns, can be applied to support the identification of sources, the quantification of atmospheric emissions, the modeling of air quality, and the investigation of potential inequities in inhalation exposure.

Simultaneous removal of heavy metals and Escherichia coli from water using silver-doped hydroxyapatite-coated activated carbon nano composite-alginate beads

The scarcity of clean water due to heavy metal and microbial contamination is a global issue. In many parts of the world, heavy metals such as Pb, Cd, and U, along with bacteria like Escherichia coli, have been found to exceed permissible limits in groundwater and other water sources that the public depends on for daily drinking water. To address this, we have synthesized a novel composite material consisting of Ag-impregnated hydroxyapatite-coated activated carbon nanoparticles embedded in alginate beads, for the simultaneous removal of heavy metals (U, Pb, and Cd) and Escherichia coli from drinking water. The material's efficiency was evaluated through a series of batch and column experiments. Batch studies indicate 90 % sequestration of U within 5 hours and Pb and Cd within 7 hours, while Escherichia coli (107 cfu/mL) was eradicated instantly. The study confirms that sorption follows pseudo-second-order kinetics via chemisorption and ion-exchange mechanisms. Fixed-bed column studies, using a logistic growth model, showed strong agreement between theoretical and experimental parameters for the Bohart-Adams, Thomas, and Yoon-Nelson models. The beads demonstrated a high affinity for heavy metals, achieving complete removal and disinfection within an empty bed contact time of 1.12 minutes. Reusability studies indicate that even after the third regeneration and reuse cycle, removal efficiency remained about 95 % for U and Pb, and 85 % for Cd. Furthermore, the effects of variations in water quality parameters such as pH, dissolved carbonates, humic acid, and ionic strength (except for Cd) on removal efficiency were minimal. In summary, the study revealed that the Ag-impregnated hydroxyapatite-coated activated carbon nanoparticles embedded in alginate beads are an efficient, sustainable, and cost-effective material for the simultaneous removal of Pb, Cd, U, and Escherichia coli from water with diverse physicochemical properties.

Occasional Occurrences and Distributions of Red Billed Quelea (Quelea quelea) Birds on Cultivating Crops during the Belg Season at Raya Azebo District of Tigray, Ethiopia

The Belg season plays a crucial role in the agricultural calendar of the Raya District, particularly due to the shortage of rainfall during the summer season. This seasonal pattern of rainfall scarcity necessitates the significance of the Belg season for agricultural activities in this region. Aim of the study was to assess the Quelea bird incidence and its association agronomic practice and environmental factors. Field survey was conducted in Raya-azebo district during 2024 Belg season. A total of 49 farmers field were assessed for the incidence and prevalence of the quelea bird. Result indicated that out of the assessed fields, 69.39% was affected by Quelea birds the assessed fields. The damage level caused by birds was varied from 0% to 100%. On average, it was determined that approximately 32.37% of the cultivated crops were affected by birds. The mean percentage of crop damage across all kebelles was observed. Ewo had the highest mean damage at 61.45%, followed by Kara-Adishaho at 57.5%. On the other hand, Tsigea experienced a significantly lower damage rate of 1.67% followed by Genete with damage rat of 11%. Independent variables such as crop types, planting time, harvesting time, source of water, and coverage of trees play a significant (p<0.05) role in influencing bird damage in belg season crops. The lowest bird damage percentage were observed in crops planted in middle March, with 6.19% and late May harvesting, with a rate of 19.38%. Adopting practices such as cultivating crops in clusters and planting crops of similar maturity at the same time can be effective strategies for controlling Quelea birds’ damage in agricultural settings.

Influence of tailing dust contamination in drinking water on the health status of goats in subtropical Regions

The contamination of river systems by tailing dust remains a constraint to goat productivity in communal farming systems. A cross-sectional study was conducted to investigate how resource-limited households in subtropical regions assessed the effects of tailing dust contamination in drinking water on the health status of goats. In a study conducted in the Ba-Phalaborwa Local Municipality, 200 households from two villages were randomly selected and interviewed using a questionnaire. Forty-eight percent (n = 96) of the households were located in contaminated areas, while 52% (n = 104) were from uncontaminated areas. The study found that poor water quality, caused by tailing dust contamination, as well as a high incidence of diseases, were key factors affecting goat productivity. Water contamination was most severe during the hot and cool dry seasons. It was also noted that goats rely on freshwater as their primary source of supplemental water during dry seasons. Urine colour, oedema of the eyelids, and kid survival were indicators for assessing the health status of goats. Nominal binary logistic regression revealed that water contamination was 2.96 more likely to be reported by youth compared to elderly members. Farmers who received informal education were 37 times more likely to report contamination than those who received formal education. High kid mortality as a health status indicator was 50 times less likely to be reported in uncontaminated areas. Intervention strategies for reducing the adverse health effects of tailing dust in contaminated areas should focus primarily on the health of goats during dry seasons.

Southern Bug River: water security and climate changes perspectives for post-war city of Mykolaiv, Ukraine

This article focuses on water security in Mykolaiv, a city of 0.5 million inhabitants in southern Ukraine, in the situation of scarcity of usable water resources caused by climate change and military operations. This problem arose after the Dnipro-Mykolaiv water pipeline was destroyed in April 2022 as a result of military operations and the supply of drinking water to the city was cut off. To ensure that the city’s population has constant access to sufficient water of acceptable quality, a search for alternative water sources and a climate risk assessment were carried out for the new municipal water supply system from the Southern Bug River. The possible change in flow and its intra-annual distribution under the influence of climate change was modeled using the WaterGAP2 hydrological model and climate projections under the SSP1-2.6 and SSP5-P8.5 scenarios. It was found that under the SSP1-2.6 scenario, the reduction in river flow will be insignificant (up to a maximum of 14% in the far future) and there will be no restrictions on the city’s water supply from this section of the river in the near (2021-2050) and far (2051-2080) period. The maximum water withdrawal for municipal water supply and the minimum environmental flow will reach their maximum value only in August (56% of the projected flow), which is not critical. Under the SSP5-8.5 scenario, in the long-term perspective of 2051-2080, the largest decrease in runoff will occur from May to October, and the water withdrawal will increase to 40-79% of the projected flow. The use of the research results not only in water management, but also in municipal administration, and their dissemination in territorial communities will contribute to the successful adaptation of socio-economic and environmental processes in the region and can bring successful benefits not only to the economy, but also to communities.

Multicriteria risk assessment of water inrush in underground mines with large-scale curtain grouting: a mine disaster risk reduction strategy

This paper presents a synthetic method to assess the risk of mine water inrush before and after large scale curtain grouting based on GIS platform. Firstly, nine factors were selected from three aspects: geological conditions, hydrogeological conditions and curtain grouting parameters, to construct a multi factor assessment model. The combined weight of every factor was determined using the minimum deviation comprehensive weighting method, which can reduce the polarization effect of various assessment methods in multicriteria decision. Then, the effectiveness of the synthetic method was validated through the Maoping lead–zinc mine in Southwest China. The mining area was divided into five zones, namely safe zone, relatively safe zone, transitional zone, relatively dangerous zone, and dangerous zone. The assessment results show that the relatively dangerous and dangerous zones were significantly reduced, while the safe, relatively safe and transitional zones were significantly increased after large scale curtain grouting. Finally, we analyze the impact of curtain grouting on the risk of mine water inrush and the mechanism of zoning evolution from three aspects: water source control, pathway sealing, drainage, and pressure reduction. This work provides an effective strategy for mine disaster risk reduction.

Towards a more sustainable hydrogen energy production: evaluating the use of different sources of water for chloralkaline electrolyzers

Water scarcity is becoming a serious threat for the implementation of energy storage devices based on hydrogen in the inland of dry regions, because of the difficulties in finding appropriate sources of water and the important environmental problem associated with the discharge of rejection saline streams produced during the purification of water. This becomes an opportunity for chloralkaline technology in which the quality of water used is lower than the required in other hydrogen production technologies. This work compares the performance of chloralkaline electrolyzers fed with different solutions of NaCl (from brackish water to brines) with that obtained feeding two natural water samples (seawater and porewater) and three processed waters (rejections streams of the electrodialysis, reverse osmosis of the porewater and a real rejection of the reverse osmosis of a vineyard). All tests were made with a lab-scale 3-D printed cell where, in addition, the performance of Ti/RuO2 and Pb/PbO2 anodes were compared, being always better the results obtained in the tests made with the Ti/RuO2 electrode. Results obtained indicate that efficiencies reached using these alternative sources are lower than those which can be reached using synthetic brines that, in turn, were very near to the standards reached in the chloralkaline industry. In the case of hydrogen production, the maximum values were obtained for seawater, reaching efficiencies proximate to 8.0 mg H2 (Wh)-1. Rejection streams of desalination processes were found to be less efficient, attaining values in the range 2 and 4 mg H2 (Wh)-1. Regarding the production of chlorine and caustic soda, better performances were reached again with seawater (161.7 mg Cl2 (Wh)-1 and 0.092 mg OH- (Wh)-1 ) and with the rejection of the electrodialysis, which also reached sound values of 90.4 mg Cl2 (Wh)-1 and 0.107 mg OH- (Wh)-1. Results obtained are promising and indicate a path that must be further worked for the implementation of a greener water management strategy in the hydrogen -based energy storage technology.

Growth performance, blood health, and antioxidant status of freshwater carp under brackish water rearing system: Sustainable aquaculture approach in arid and semi-arid conditions

Global warming, water salinization, and increased anthropogenic usage of freshwater sources have had severe effects on water sources and aquaculture practices, which is consequently putting pressure on aquatic fauna and fish production. Hence, brackish water can be used as an alternative and sustainable approach to meet the increasing food requirements. Four groups with triplicates were designed to evaluate the impact of brackish water on Cirrhinus mrigala (n = 100) for 180 days; T0: control group (freshwater), T1: (5.45 ppt salinity), T2: (8.45 ppt salinity) and T3 (12.45 ppt salinity). Little behavioural alterations and normal feeding were observed in all experimental groups as compared to control group, except group T3. Survival rate was 100 % in all groups excluding group T3, which had shown 88 % survival rate (P < 0.05), while mean weight gain and length gain were observed better with low FCR in T1 and T2 groups (P < 0.05) but best growth rate observed at 5 ppt salinity level. Significant reduction in haemoglobin (Hb), hematocrit (HCT), red blood cells (RBCs) and increase in white blood cells (WBCs) and platelets (PLTs) was observed in group T3 compared to other experimental groups (P < 0.05). ALT, AST, ALP, urea, creatinine, and triglycerides, exhibited significant changes in T3 group after 180 days (P < 0.05). Erythrocytes had shown morphological alterations as; micronuclei, notching, blebbing, pear-shaped nuclei and spherocytes in T3 group. Significant increase in DNA damage in various tissues had indicated potential genotoxic impact of highly saline brackish water. Oxidative stress markers were increased significantly and antioxidants reduced (P < 0.05) at high salinity level brackish water (T3) until 180 days. In conclusion, C. mrigala can potentially grow well in brackish water system at 5 ppt salinity whereas, rise in salinity level (12 ppt) is detrimental to freshwater fish health and growth.

Heavy Metal Identification in Water Resources and the Surrounding Environment of the Cirasea Riparian Zone, Indonesia

The Cirasea River can provide water for both the Bandung basin and agricultural irrigation. Intensive agriculture, industry, and land use changes could have an impact on water quality. The purpose of this study is to look at the origins of heavy metals in riparian water resources. Heavy metal analysis was performed on 13 groundwater and river water samples. Heavy metals in water sources were compared with sediment and soil. The samples were analyzed for heavy metals using an AAS instrument. The research method employs statistical, geographical, and heavy metal pollution index (HPI). The HPI for river water was 131, whereas groundwater was 93. River water with an HPI value of more than 100 is highly polluted, indicating that it is unsafe for human consumption and has negative health consequences. Data verification with heavy metals in sediments reveals the presence of heavy metals coming from geogenic circumstances in various locations in the upstream area. Heavy metals in downstream areas result from geological factors and anthropogenic activities in the surrounding area. The long-term effects of heavy metal pollution along the riparian zone will become apparent. More research is needed on communities that depend on groundwater supplies along the Cirasea watershed.

Photocatalytic degradation of norfloxacin antibiotic by a novel Cu-ZnO/BiOI/Bi2WO6 double Z-type heterojunction: Performance, mechanism insight and toxicity assessment

A novel double Z-type Cu-ZnO/BiOI/Bi2WO6 photocatalyst was synthesized using one-pot hydrothermal method. The effects of Bi2WO6 and Cu-ZnO contents, antibiotic concentration, catalyst dosage, solution pH value, coexisting ions, antibiotic types, mixed antibiotic types, water source and light source on the catalytic performance of the Cu-ZnO/BiOI/Bi2WO6 were investigated. Remarkably, under visible light irradiation, the removal rate of 20 mg/L norfloxacin reached 94.32 % within 120 min using the optimized Cu-ZnO/BiOI/Bi2WO6 photocatalyst, and its pseudo-first-order reaction rate constants were 5.63 and 1.80 times higher than those of BiOI and BiOI/Bi2WO6, respectively. The toxicity prediction and experimental findings indicated that the toxicity of the degraded norfloxacin (NOR) solution was notably diminished. The Cu-ZnO/BiOI/Bi2WO6 catalyst exhibited excellent salt tolerance, high reusability stability, universality and spectral response. Outstanding photocatalytic performance of Cu-ZnO/BiOI/Bi2WO6 photocatalyst is primarily due to the co-recombination of Cu-ZnO and Bi2WO6 on BiOI, which increases the surface area and active sites of the catalyst. More importantly, the double Z-type heterojunction, created through the intimate union of the semiconductor boundary within the composite catalyst, enhances the interface charge transport efficacy and the efficiency of separating photogenerated carriers. Finally, in conjunction with a diverse range of experimental methodologies, the degradation pathway of NOR through the Cu-ZnO/BiOI/Bi2WO6 composite catalyst and the electron transfer mechanism within the double Z-type heterojunction have been comprehensively elucidated. This study provides a pioneering reference for optimizing BiOI-based heterojunction catalysts and addressing antibiotic-contaminated wastewater treatment.

Quercus acutissima exhibits more adaptable water uptake patterns in response to seasonal changes compared to Pinus massoniana

BackgroundSeasonal precipitation variability significantly affects water use in forests; however, whether water uptake is adapted to changes in precipitation, particularly whether it could affect the coexistence of tree species, has rarely been quantified in forest systems. MethodIn this study, dual stable isotopes and the Li-6400 portable photosynthesis system were used to determine the water sources of a mixed conifer (Pinus massoniana) and broadleaf (Quercus acutissima) forest and changes in hydraulic characteristics during the dry and wet seasons in a southern hilly region of China. ResultsAlthough the hydraulic characteristics of P. massoniana were lower than those of Q. acutissima, it maintained a stable water source from the deep soil layer and a higher stomatal conductance (Gs), leading to a higher transpiration rate (Tr) during the growing seasons. Q. acutissima mainly absorbed water from deeper soil layers in the dry season and took up from shallow soil layers in the wet season. Its Gs values exhibited sensitivity to precipitation, while it maintained a lower Tr value during the growing seasons. The excessive water-use strategy observed in P. massoniana may confer weak drought-tolerance during higher frequency and more intense extreme precipitation events, whereas Q. acutissima may exhibit better ecological adaption to precipitation changes. ConclusionsThe overlap of water niches in mixed forests did not appear to affect the coexistence of tree species. The present study provides insights into reforestation and water management in the southern hilly regions of China.

Effective synthesis and characterization of citric acid cross-linking of modified ferrous metal-organic framework and chitosan nanocomposite sponge for Th(IV) elimination: Adsorption isotherms, kinetic analysis, and optimization by Box-Behnken design

This research presents a novel nanocomposite of ferrous metal-organic framework (Fe(II)-MOF) that has been encapsulated with chitosan matrix, leading to the development of a new adsorbent referred to as NH2-Fe(II)-MOF@CSC composite sponge. This composite sponge has shown effectiveness in removing radioactive thorium (IV) contamination from water sources. The adsorbent underwent characterization using techniques including FTIR, PXRD, BET analysis, and SEM. The adsorbent has a high surface area of 1360.8 m2/g. The most effective conditions for adsorbing Th(IV) were found to be a pH of 5, using 0.02 g of adsorbent dose per 25 mL, and maintaining a contact time of 100 min. The composite sponge demonstrated an impressive maximum adsorption capacity of 618.8 mg/g for Th(IV). The adsorption process was fitted to Langmuir isothermally and kinetically fitted to pseudo-second-order. Nonetheless, the relatively low adsorption energy of 6.22 kJ/mol suggests that the main adsorption mechanism is physisorption, which is marked by weaker van der Waals forces. This discovery could have implications for the material's potential for easy regeneration. In the analysis of the influence of temperature on the adsorption of Th(IV), it was discovered that the adsorption process is endothermic because the positive ΔHo value was 24.48 kJ.mol−1. Furthermore, a positive ΔSo value of 87.46 J.mol−1 K−1 suggests the existence of disorder at the solid-solution interface. Conversely, a temperature rise resulted in a higher negatively charged ΔGo, indicating that the adsorption process is spontaneous. The research also examined the mechanism of interaction, such as π-π interaction, hydrogen bonding, pore filling, and electrostatic interaction. It was noted that the adsorbent can be efficiently used for a maximum of six cycles, demonstrating its economic viability. The adsorption outcomes were optimized using the Box Behnken design (BBD).

Kinetic modeling and optimization of triclosan adsorption onto coconut shell activated carbon

This study investigates the efficacy of activated carbon derived from coconut shells for the removal of Triclosan (TCS) from aqueous solutions. Experimental results demonstrate the impressive efficiency of coconut shell-derived activated carbon in eliminating TCS from water. Statistical analysis underscores the significant role of agitation in enhancing adsorption efficiency, with increased agitation leading to higher contaminant removal rates. Equilibrium is rapidly achieved, with removal efficiencies exceeding 85%. Kinetic analysis reveals rapid adsorption kinetics, predominantly following the pseudo-second-order model. Additionally, intraparticle diffusion analyses provide insights into TCS diffusion within activated carbon pores, highlighting its dependence on solute concentration. These findings underscore the potential of coconut shell-derived activated carbon as a viable solution for mitigating TCS contamination in water sources, contributing to the development of effective water treatment strategies.

Assessment of Animal Drinking Water Quality in Livestock Farms in Galapagos Islands

The purpose of this research was to determine the quality of water for bovine consumption on livestock farms in the El Progreso parish - Galapagos by applying a quality index following the Brown methodology proposed by the National Sanitation Foundation of the United States. Information was collected from the livestock farms through a socio-environmental diagnosis of the area, where five localities were considered: San Joaquín, Las Goteras, Cerro Verde, Puerto Chino and El Progreso from which fifteen livestock farms were selected for the respective sampling of the sources. of water. Therefore, nine parameters were considered for the analysis of the respective water sources: pH, TDS, Fecal Coliforms, electrical conductivity, hardness, nitrites, phosphates, temperature and turbidity. Of the total livestock farms monitored, three of them presented a rating of Good quality in a range of 70 to 90, while the remaining farms recorded values with a Medium classification, which are those that recorded AQI values between 51 to 70 according to the criteria established by the NSF. This research highlights the importance of frequently carrying out analyzes of the water sources from which cattle drink to determine the quality of the resource, and also provide technical advice to ranchers in the area on the management and cleaning of the reservoirs.

Water sources and threshold behaviors of streamflow generation in a mountain headwater catchment

Numerous studies have analyzed the event-scale rainfall-runoff response of hillslopes and catchments. However, there are still knowledge gaps when it comes to understanding the spatiotemporal sources of headwater catchment runoff and the threshold behaviors of multiple runoff components. The aim of this study is to investigate the complex runoff generation mechanisms for 244 rainfall events in a humid headwater catchment of eastern China over five years (2011–2015). We employ a combined approach of isotopic tracing (δ2H and δ18O) and fully-integrated surface/subsurface flow modeling (HydroGeoSphere) to identify streamflow compositions and how the process chain of “rainfall infiltration, mixing with soil water, and subsequent exfiltration to the hillslope surface” impacts streamflow generation in headwater catchments. Our results show that the streamflow consists of event and pre-event water. Event water is composed of direct runoff from rainfall (2 % in the total streamflow) and indirect runoff from infiltrated rainfall (24 %). Pre-event water comprises the exfiltrated shallow soil water of indirect runoff (37 %) and subsurface flow (37 %). The study highlights the significant role of indirect runoff, comprising infiltrated rainfall and pre-event shallow soil water, in streamflow generation, reaching a peak proportion of 81.4 % during rainfall events. In addition, we quantify the threshold behaviors (including the generation threshold, and critical threshold from increasing to decreasing state) for surface and subsurface flow, based on the analysis of the non-linear rainfall-runoff relationships observed in the catchment. Results show that rainfall amount of 33 mm and rainfall intensity of 9 mm/d are generation thresholds for direct runoff and critical thresholds for proportion changes of exfiltrated shallow soil water. Critical thresholds of 55 mm for rainfall amount and 12 mm/d for rainfall intensity are identified for proportion changes of infiltrated rainfall and total indirect runoff. Our findings highlight that the combined analysis of hydrological modeling and isotopic tracing provides an effective solution for quantifying the roles of dominant water components in streamflow generation and elucidate the distinct threshold behaviors during rainfall events. Enhancing our comprehension of streamflow origins and their response mechanisms to rainfall events will improve the understanding of streamflow generation in headwater catchments.

Determination of Hydrogen Fuel Production from GIS-Based Selected Ponds Using Hybrid Renewable Energy Systems in Kayseri

This study offers the feasibility study of large-scale hydrogen production to establish environmentally friendly hybrid energy facilities based on wind and solar energy resources in the vicinity of lakes and rivers within the Kayseri region of Türkiye. The ultimate objective is to enable hydrogen production from lakes and rivers and identify optimal locations for the installation of hydrogen fuel stations. The precise selection of locations for the designated province is based on geographical, environmental, and infrastructural considerations by utilizing GIS technology which allows spatial analysis and superimposition of various layers. The methodology also involves the utilization of the HOMER software to facilitate the integration of wind and solar power, along with hydrogen production, providing a platform for environmentally friendly energy system design and optimization. A comprehensive evaluation has been conducted for the sizing and placement of renewable energy systems based on microgrid analysis, the design of hydrogen production facilities, and the establishment of hydrogen refuelling infrastructure. The study also incorporates a financial analysis to assess the economic viability of the project over its lifecycle. Among the five water sources considered, the highest annual hydrogen production is 830 tons in Zamantı River, while Kızılırmak River has the lowest value according to LCOE and LCOH values, 0.030 $/kWh and 3.85 $/kgH2, respectively.

Study on the response mechanisms and evolution prediction of groundwater microbial-toxicological indicators.

This study aims to investigate the response mechanisms of groundwater microbial-toxicological indicators, specifically total bacteria count (TBC) and total coliform count (TCC), to water quality indicators and environmental conditions. Using data from a water source in the western plateau of China, a predictive model focusing on TBC and TCC was developed. An orthogonal experimental design was employed to manipulate environmental conditions such as temperature, pH, and porosity, facilitating laboratory experiments. These experiments measured pH, chemical oxygen demand (COD), oxidation-reduction potential (ORP), TBC, and TCC at varying depths and environmental conditions. Principal component analysis elucidated the mechanisms by which water quality indicators and environmental conditions affect groundwater microbial-toxicological indicators. A prediction model for these indicators in plateau regions was established based on a backpropagation neural network (BP-NN), using TBC and TCC as target variables and the newly extracted principal components as influencing factors. The results demonstrate that environmental conditions and water quality indicators primarily influence the evolution of groundwater microbial-toxicological indicators by altering the ionic charge quantities, redox conditions, and temperature of the groundwater. The predictive model for groundwater microbial-toxicological indicators shows trends consistent with experimental outcomes, with an average relative error of less than 15%, meeting engineering requirements. PRACTITIONER POINTS: The values of total bacteria count (TBC) and total coliform count (TCC) under different conditions were obtained by column experiments. The influence mechanism of environmental conditions and groundwater indicators on TBC and TCC was elaborated by principal component analysis. TBC and TCC prediction models were established through the investigation of water sources in a plateau area and laboratory experiments.