Search Results (74)

This paper presents the Green Watershed Index (GWI) methodology, focusing on the 17 sustainability indicators selected in the Razey watershed, NW Iran. Field surveys and data collection have provided the possibility of field inspection and measurement of the present condition of the watershed and the indicators taken. Based on the degree of compliance with the required process, each indicator was scored from 0 to 10 and classified into three categories: unsustainable, semi-sustainable, and sustainable. Using the Entropy method to assign weight to each indicator and formulating a proportional mathematical relationship, the GWI score for each sub-watershed was derived. Spatial changes regarding the selected indicators and, consequently, the GWI were detected in the study area. Development of water infrastructure, particularly in the upstream sub-watersheds, plays a great role in increasing the GWI score. The highest weight is related to environmental productivity (0.26), and the five indicators of water footprint, knowledge management and information quality system, landscape attractiveness, waste recycling, and corruption control have approximately zero weight due to their monotonous spatial distribution throughout sub-watersheds. Only sub-watershed R1 has the highest score (5.13), indicating a semi-sustainable condition. The rest of the sub-watersheds have unsustainable conditions (score below 5). Concerning the GWI, the watershed is facing a critical situation, necessitating the implementation of management and conservation strategies that align with the sustainability level of each sub-watershed. Full article

Rizhao Reservoir, Shandong Province, China, as a key regional water supply hub, provides water for domestic, industrial, and agricultural uses in and around Rizhao City by intercepting runoff, which plays a central role in guaranteeing water supply security and supporting regional development. This study systematically collected 66 surface water samples to elucidate the hydrochemical characteristics within the reservoir area, identify the principal influencing factors, and clarify the sources of dissolved ions, aiming to enhance the understanding of the prevailing water quality conditions. A systematic analysis of hydrochemical facies, solute provenance, and governing processes in the study area’s surface water was conducted, employing an integrated mathematical and statistical approach, comprising Piper trilinear diagrams, correlation analysis, and ionic ratios. Meanwhile, the entropy weight-based water quality index (EWQI) and irrigation water quality evaluation methods were employed to assess the surface water quality in the study area quantitatively. Analytical results demonstrate that the surface water system within the study area is classified as freshwater with circumneutral to slightly alkaline properties, predominantly characterized by Ca-HCO₃ and Ca-Mg-SO₄-Cl hydrochemical facies. The evolution of solute composition is principally governed by rock–water interactions, whereas anthropogenic influences and cation exchange processes exert comparatively minor control. Dissolved ions mostly originate from silicate rock weathering, carbonate rock dissolution, and sulfate mineral dissolution processes. Potability assessment via the entropy-weighted water quality index (EWQI) classifies surface waters in the study area as Grade I (Excellent), indicating compliance with drinking water criteria under defined boundary conditions. Irrigation suitability analysis confirms minimal secondary soil salinization risk during controlled agricultural application, with all samples meeting standards for direct irrigation use. Full article

This study applies the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method combined with entropy-based weighting to systematically rank Serbian municipalities regarding economic vitality, infrastructure quality, and socio-economic stability. By developing a composite municipal performance index, the research explores the extent to which stronger economic standings relate to public safety outcomes. Infrastructure factors—including road conditions, housing quality, and water supply—are assessed through correlation and t-tests to evaluate their influence on municipal economic rankings. An ordinary least squares (OLS) regression model also examines how education and health expenditures per capita contribute to broader socio-economic resilience. The findings reveal a moderately strong, though nonlinear, negative relationship between economic performance and crime rates, with road infrastructure emerging as a consistently significant driver of economic strength. Investments in education and health initially correlate with greater municipal stability but show signs of diminishing marginal impact over time. These insights contribute to understanding the complex interplay between governance, infrastructure, and safety in transitional economies, highlighting the value of integrated data-driven approaches for regional development planning. Full article

Groundwater nitrate (NO₃⁻) contamination has emerged as a critical global environmental issue, posing serious human health risks. This study systematically investigated the hydrochemical processes, sources of NO₃⁻ pollution, the impact of land use on NO₃⁻ pollution, and drinking water safety in an urban area of southwestern China. Thirty-one groundwater samples were collected and analyzed for major hydrochemical parameters and dual isotopic composition of NO₃⁻ (δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻). The groundwater samples were characterized by neutral to slightly alkaline nature, and were dominated by the Ca-HCO₃ type. Hydrochemical analysis revealed that water–rock interactions, including carbonate dissolution, silicate weathering, and cation exchange, were the primary natural processes controlling hydrochemistry. Additionally, anthropogenic influences have significantly altered NO₃⁻ concentration. A total of 19.35% of the samples exceeded the Chinese guideline limit of 20 mg/L for NO₃⁻. Isotopic evidence suggested that primary sources of NO₃⁻ in groundwater include NH₄⁺-based fertilizer, soil organic nitrogen, sewage, and manure. Spatial distribution maps indicated that the spatial distribution of NO₃⁻ concentration correlated strongly with land use types. Elevated NO₃⁻ levels were observed in areas dominated by agriculture and artificial surfaces, while lower concentrations were associated with grass-covered ridge areas. The unabsorbed NH₄⁺ from nitrogen fertilizer entered groundwater along with precipitation and irrigation water infiltration. The direct discharge of domestic sewage and improper disposal of livestock manure contributed substantially to NO₃⁻ pollution. The nitrogen fixation capacity of the grassland ecosystem led to a relatively low NO₃⁻ concentration in the ridge region. Despite elevated NO₃⁻ and F⁻ concentrations, the entropy weighted water quality index (EWQI) indicated that all groundwater samples were suitable for drinking. This study provides valuable insights into NO₃⁻ source identification and hydrochemical processes across varying land-use types. Full article

Groundwater is crucial for human survival and social development. In this study, ArcGIS 10.8, Origin 2024, and Excel were employed to investigate the hydrochemical properties of groundwater in the Rizhao reservoir (RZR) through statistical analysis, Durov plots, ion ratio analysis, and the entropy weight water quality index (EWQI). The analysis is based on monitoring data from six sites located both upstream and downstream of RZR, focusing on dynamic changes in groundwater quality and major ion concentrations. The findings suggest that the groundwater in RZR exhibits weak alkalinity and is categorized as hard freshwater. The predominant anion and cation are HCO₃⁻ and Ca²⁺, which together determine that the dominant water chemistry type in RZR is HCO₃-Ca type. Groundwater ions predominantly stem from the dissolution of silicate and evaporite rocks. In comparison to the dry season, the fluctuations in groundwater parameters are more pronounced during the wet season. Between 2020 and 2022, the concentrations of most ions exhibited an upward trend. Notably, nitrate (NO₃⁻) experienced significant fluctuations and relatively high concentrations, peaking in the wet season of 2023. The primary source of nitrate in RZR is agricultural activities. Overall, the quality of groundwater in RZR is good and suitable for human consumption. Nevertheless, the EWQI values are increasing at most monitoring sites, with the most significant rise observed at site R02. Moreover, while the upstream monitoring point exhibits better water quality, its EWQI value has increased significantly, and ion concentrations display substantial fluctuations. Local authorities are advised to adopt active measures to manage groundwater quality in RZR to ensure its sustainable use. Full article

As an important ecological barrier in the upper reaches of the Yangtze River, the Jialing River Basin has complex and sensitive hydrochemical evolutionary mechanisms due to its geological structures and human activities. This study focuses on the groundwater in the Wusheng section of the Jialing River Basin, combining field investigations and Entropy-Weighted Water Quality Index (EWQI) calculations to analyze its hydrochemical characteristics and influencing factors and conduct a water quality assessment. The results show that this regional water body has a pH of 7.05–8.36, presenting weakly alkaline and low-mineralization characteristics, with differences in hydrochemical components between groundwater and surface water. The ions are predominantly controlled by rock weathering, with reactions such as halite and gypsum dissolution occurring during groundwater runoff. Groundwater in the tectonic influence zone exhibits abnormal chemical compositions due to lateral recharge from different strata along fracture channels and long-distance runoff reactions with the surrounding rocks. EWQI values for groundwater range from 6.07 to 104.02, with an average value of 37.46, generally exhibiting a trend of increasing EWQI values near the Jialing Riverbank. In this area, 96.15% of groundwater meets excellent or good quality standards and is suitable for direct drinking. The influence of the intensity of different indicators on groundwater quality decreases in the order of Ca²⁺ > Cl⁻ > Mg²⁺ > SO₄²⁻ > HCO₃⁻ > NO₃⁻. Water quality is primarily influenced by the primary geological background, while agricultural practices may also lead to its deterioration. Full article

Understanding the coupling mechanisms and coordinated development dynamics of the water–energy–food (WEF) system is crucial for sustainable river basin development. This study focuses on the Yellow River Basin, conducting a comprehensive analysis of the system’s coupling mechanisms and influencing factors. A structured evaluation framework is established, integrating the entropy weight–TOPSIS method, the coupling coordination degree model, and spatial correlation analysis. Empirical analysis is conducted using data from nine provinces (regions) along the Yellow River from 2003 to 2022 to assess the spatiotemporal evolution of the coupling coordination level. The Tobit regression model is employed to quantify the impact of various factors on the system’s coupling coordination degree. Results indicate that the comprehensive evaluation index of the WEF system in the Yellow River Basin exhibits an overall upward trend, with the system coupling degree remaining at a high level for an extended period, up from 0.231 to 0.375. The interdependence among the three major systems is strong (0.881–0.939), and while the coupling coordination degree has increased over time despite fluctuations, a qualitative leap has not yet been achieved. The evaluation index follows a spatial distribution pattern of midstream > downstream > upstream, characterized by a predominantly high coupling degree. However, the coordination degree frequently remains at a forced coordination level or below, with a general trend of midstream > downstream > upstream. From 2003 to 2008, a positive spatial autocorrelation was observed in the coupling and coordinated development of the WEF system across provinces, indicating a strong spatial agglomeration effect. By 2022, most provinces were clustered in “high-high” and “low-low” areas, reflecting a positive spatial correlation with minimal regional differences. Key factors positively influencing coordination include economic development levels, industrial structure upgrading, urbanization, and transportation networks, while technological innovation negatively affects the system’s coordination. Based on these findings, it is recommended to strengthen balanced economic development, optimize the layout of industrial structures, improve the inter-regional resource circulation mechanism, and promote the deep integration of technological innovation and production practices to address the bottlenecks hindering the coordinated development of the water–energy–food system. Policy recommendations are proposed to provide strategic references for the sustainable socioeconomic development of the Yellow River Basin, thereby achieving the high-quality coordinated growth of the water–energy–food system in the region. Full article

In this study, a total of 26 groundwater samples were collected from the northwest of the Sichuan Basin. Statistical analysis revealed that Ca²⁺ was the predominant cation, followed by Na⁺, Mg²⁺, and K⁺. The anion concentrations followed the order HCO₃⁻ > SO₄²⁻ > NO₃⁻ > F⁻ > Cl⁻. Consequently, Ca-HCO₃ was identified as the dominant hydrochemical type in the study area. Geochemical modeling results indicated that silicate weathering and cation exchange processes were the primary factors influencing groundwater hydrochemistry. To provide an accurate assessment of water quality, a Comprehensive Water Quality Index (CWQI) was applied in this study. This novel method combined factor analysis and the entropy-weighted approach to derive integrated weights for water quality calculation. The CWQI results showed that 73.08% of the samples were classified as excellent for drinking, while 26.92% were classified as good. Sensitivity analysis further demonstrated the robustness of the drinking water quality model. The findings of this study could contribute to the enhancement of water quality evaluation in the Sichuan Basin. Full article

This study determined the hydro-chemical properties of groundwater in a typical mining area and its associated human health risks, focusing on the Guangwang mining area. Groundwater samples were analyzed for toxic metals, after which analysis of principal components, the entropy-weighted water quality index, and Spearman analysis of correlation were applied to the collected data. The Environmental Protection Agency of the United States’s health hazard appraisal was utilized to assess the hazards of toxic metals in the local water supply to the health of both grownups and juveniles. HCO₃-Na and SO₄⋅Cl-Ca⋅Mg were found to be the predominant groundwater hydro-chemical types. The eastern section of the area of study showed the greatest average total dissolved solids (16,347.00 mg/L) and SO₄²⁻ (8980.00 mg/L) levels. It was determined that the groundwater hydro-chemical type was Ca-HCO₃ and that limestone leeching and the evaporative level in the coal seam aquifer were the predominant factors regulating groundwater hydrochemistry. Six of the ten assessed metals exceeded the World Health Organization’s safe water for drinking standards, with particularly high Al (66.97 mg/L) and Cd (194.53 μg/L). Spearman correlation analysis showed significant correlations between Mn, Al, Cu, and Zn, which could be attributed to bauxite minerals associated with the coal mine. Release of metal ions was attributed to the oxidation of metal sulfide minerals, which is driven by mining-induced water–rock interaction. The intake of water for drinking was shown to be the predominant route of hazard to human health. The hazard index decreased from east to west due to the level of abandoned coal mines in the eastern region, along with well-developed fissures. The total carcinogenic hazard for grownups exceeded that of juveniles due to the greater quantity of water for drinking consumed and higher surface area of skin amongst grownups. The results can guide groundwater pollution regulation activities in mining areas to minimize potential hazards of groundwater quality to the health of humans. Full article

The terminal tributaries of karst rivers are often under-researched, with low investigation coverage and incomplete surveys. These areas face significant human activity disturbances, fragile soil and water environments, and insufficient research on water quality conditions. Residents in their basins are confronted with urgent issues of water scarcity and deteriorating water quality. This study focused on the Zhongdu River Basin, a terminal tributary in the Pearl River system in Southwest China. By measuring the conventional hydrochemical parameters and stable isotope ratios (e.g., δ¹⁸O and δ²H), this study employed methods such as hydrological and geochemical approaches, as well as classical statistical analyses, to reveal the hydrochemical characteristics, regulatory mechanisms, and water health status in the basin. Data show that the water in the Zhongdu River Basin is generally weakly alkaline, with a pH range between 6.46 and 8.28. The highest values for electrical conductivity (EC) and total dissolved solids (TDSs) are found upstream, reaching 497 μS/cm and 324.5 mg/L, respectively. The average dissolved oxygen (DO) value is 71.3 mg/L. The hydrochemical type is primarily HCO₃⁻-Ca²⁺, with Ca²⁺ and HCO₃⁻ as the dominant ions. The surface water in the middle and lower reaches of the basin is strongly influenced by evaporation, with atmospheric precipitation as the main recharge source. Rock weathering is the primary influencing factor in the basin, with most minerals in a dissolved state. Agricultural activities are the primary pollution source in the basin, with domestic pollution having a minimal effect on water quality. Water quality was assessed using the entropy-weighted water quality index (EWQI) based on 11 parameters, indicating overall good water quality, classified as Grade I. The findings indicate that human activities have a minimal impact on the water quality in the region, and the basin is expected to maintain its healthy condition for an extended period. Full article

The United Nations Sustainable Development Goal (SDG) 11.1 emphasizes improving well-being, ensuring housing security, and promoting social equity. Informal settlements, one of the most vulnerable groups, require significant attention due to their dynamic changes and habitat quality. These areas limit the ability to comprehensively capture spatial heterogeneity and dynamic shifts in regional sustainable development. This study proposes an integrated approach using multi-source remote sensing data to extract the spatial distribution of informal settlements in Mumbai and assess their habitat environment quality. Specifically, seasonal spectral indices and texture features were constructed using Sentinel and SAR data, combined with the mean decrease impurity (MDI) indicator and hierarchical clustering to optimize feature selection, ultimately using a random forest (RF) model to extract the spatial distribution of informal settlements in Mumbai. Additionally, an innovative habitat environment index was developed through a Gaussian fuzzy evaluation model based on entropy weighting, providing a more robust assessment of habitat quality for informal settlements. The study demonstrates that: (1) texture features from the gray level co-occurrence matrix (GLCM) significantly improved the classification of informal settlements, with the random forest classification model achieving a kappa coefficient above 0.77, an overall accuracy exceeding 0.89, and F1 scores above 0.90; (2) informal settlements exhibited two primary development patterns: gradual expansion near formal residential areas and dependence on natural resources such as farmland, forests, and water bodies; (3) economic vitality emerged as a critical factor in improving the living environment, while social, natural, and residential conditions remained relatively stable; (4) the proportion of highly suitable and moderately suitable areas increased from 65.62% to 65.92%, although the overall improvement in informal settlements remained slow. This study highlights the novel integration of multi-source remote sensing data with machine learning for precise spatial extraction and comprehensive habitat quality assessment, providing valuable insights into urban planning and sustainable development strategies. Full article

Groundwater is crucial for domestic, agricultural, and ecological uses, particularly in the lower reaches of arid basins, where its quality often limits availability. A total of 26 phreatic groundwater samples were collected from a typical endorheic watershed on the Tibetan Plateau to assess the hydrochemical characteristics of phreatic groundwater in the lower reaches of arid inland watersheds. The hydrochemical characteristics, quality, and formation mechanisms of groundwater were analyzed using the Entropy-Weight Water Quality Index (EWQI), irrigation water quality indexes (such as sodium adsorption ratio, soluble sodium percentage, and permeability index), hydrochemical diagrams, and correlation analysis. The findings indicate that phreatic groundwater in the lower reaches is slightly alkaline, with a substantial TDS variation from 252.58 to 1810.41 mg/L. Groundwater is predominantly characterized by fresh hydrochemical facies of HCO₃-Ca and HCO₃-Na types, with a few saline Cl-Na types present. The concentrations of NO₃⁻, NO₂⁻ and NH₄⁺, in groundwater range from 0.32 to 100.00 mg/L, 0.00 to 0.48 mg/L, and 0.00 to 0.20 mg/L, respectively, and 3.59%, 26.92%, and 7.69% of the samples exceeding the permissible drinking limits recommended by Chinese guideline and World Health Organization. Groundwater is classified as fresh at 80.8% of sampling sites and brackish at 19.2%. Approximately 96.2% of the sampled groundwaters is rated as excellent to medium quality according to EWQI assessments, suitable for domestic use, while 3.8% is of extremely poor quality and should be avoided for direct consumption. Groundwater from all sampling sites is suitable for agricultural irrigation and does not pose permeability hazards to the soil. Most groundwaters are suitable for long-term irrigation in terms of sodium hazards, with only 3.8% and 7.7% of samples falling into the “Permissible to Doubtful” and “Doubtful to Unsuitable” categories, respectively. Salinity poses the primary threat in long-term irrigation, with 38.5%, 53.8%, and 7.7% of sampled groundwaters exhibiting moderate, high, and very high salinity risks, respectively. Groundwater chemistry is primarily governed by water-rock interaction and evaporation, with additional impacts from agricultural inputs of nitrogen contaminants and chemicals. Agricultural practices contribute to elevated groundwater salinity in the study area, while natural evaporation drives salinity accumulation in the lower parts. In managing and utilizing groundwater resources in the study area and similar arid regions globally, attention should be paid to salinity caused by agricultural activities and natural evaporation, as well as nitrogen pollution from farming. Full article

Results change depending on the water quality evaluation methods used, and within good-quality water, many results still have parameters with concentrations exceeding the World Health Organization (WHO) desirable limits or national threshold values (TVs). Furthermore, there are few methods to classify the severity degree of contaminated water; most methods have problems in the parameter threshold boundary and in assigning weights. Aiming to solve the above problems, a water quality evaluation framework based on the single-indicator evaluation method (SIE), Weber–Fechner (W-F) law and Probabilistic Neural Network (PNN) is presented, named SIE&W-F&PNN. Forty-three confined water samples were collected for this research in Xi’an in September 2015. The SIE, water quality index (WQI) with three different weights (method weight, entropy weight and equal weight), comprehensive evaluation method (CEM) and SIE&W-F&PNN method were used, and the evaluation criteria for contaminated water were proposed based on the W-F law. The results of these methods were compared. The reasons for confined water pollution in Xi’an were analyzed. The results show that TC, NH₄-N, NO₂-N, β, As, Mn, F⁻, TH, Fe²⁺ and Turb were the contaminating parameters of the 43 confined water samples. In order, the results for the number or ratio of ‘Poor’ and even worse water samples by method are as follows: SIE-WHO (30, 69.77%) > SIE-GB = CEM (24, 55.81%) > WQI (entropy weight) (12, 27.91%) > WQI (method weight) (10, 23.26%) > WQI (equal weight) (9, 20.93%). These discrepancies highlight the influence of evaluation methods on the results. For this study, a water sample was classified as ‘contaminated (bad) water’ if any parameter exceeded either the national TV or the WHO’s desirable limit, prioritizing drinking water safety. The SIE&W-F&PNN results show that there were 10 excellent water samples and 33 bad water samples (among which 4 water samples were rated as VL (very lightly polluted), 14 as L (lightly polluted), 14 as M (moderately polluted) and 1 as H (heavily polluted)). The SIE&W-F&PNN method ensures that no parameters in ‘excellent’ or ‘good’ water samples exceed the WHO’s desirable limits or national TVs; can be used to classify the severity of contamination of contaminated water without assigning weights, avoiding the rate mutation near the threshold boundary; and can include any number of parameters and be applied to lakes, rivers, air, soil, etc. (i.e., it is not unique to groundwater). The primary causes of confined water pollution in Xi’an include historical pollution, contemporary anthropogenic activities, geological factors, excessive groundwater extraction, and the infiltration of contaminated surface and phreatic water. Full article

Groundwater is a vital and invaluable resource on our planet, serving as a critical water supply for human life, industrial activities, and agricultural production. It plays a pivotal role in sustaining human existence and driving societal progress. In this study, we conducted a comprehensive analysis of the hydrochemical characteristics and controlling factors of groundwater in the Upper Weihe River (UWR) using statistical analysis, Piper diagrams, Gibbs diagrams, correlation analysis, and ion ratio analysis. To evaluate the suitability of the regional groundwater for potable use, we employed the entropy weight water quality index (EWQI). Additionally, the sodium adsorption ratio (SAR) and percentage of soluble sodium (Na%) were utilized to evaluate the groundwater’s adaptability to irrigation. Furthermore, this study also assessed the health risks faced by adults and children in the UWR. The findings indicate that the main cations and anions in groundwater are Ca²⁺ and HCO₃⁻, respectively. The hydrochemical types are predominantly HCO₃-Ca, Cl-Ca, and mixed types. The composition of groundwater is primarily influenced by the dissolution of silicate and carbonate minerals, with cation exchange also playing a significant role in shaping its hydrochemical characteristics. The water quality assessment indicates that the majority of groundwater in UWR is classified as “excellent” or “good”, rendering it suitable for human consumption. However, 7.17% of the water samples were of poor quality and unsuitable for drinking; these were primarily located in a few areas in the northern and western parts of the study area. Regarding irrigation, 94.83% of the groundwater is deemed very suitable; however, a small fraction is not appropriate for such use. Additionally, non-carcinogenic risks are generally higher across most parts of the study area for both children and adults, with children exhibiting significantly higher risks than adults. These findings offer crucial insights regarding the sustainable management and environmental conservation of groundwater resources in the UWR. Full article

Groundwater is a significant source of water, and evaluating its hydrochemical attributes, quality, and associated health risks holds paramount importance in guaranteeing safe water access for the population and fostering sustainable socio-economic progress. Situated within a semi-arid region, the Dianbu area (DBA) features numerous greenhouses interspersed amongst open farmlands. An examination revealed a discernible decline in the overall water chemistry environment in this area. This study extensively examined the fundamental water chemistry characteristics of groundwater and surface water samples through a statistical analysis, Piper’s trilinear diagram, ion ratios, and other analytical methods. The assessment of irrigation water quality was conducted using the entropy weight water quality index (EWQI), sodium adsorption ratio (SAR), percentage of soluble sodium (Na%), among other relevant indicators. The findings demonstrate multiple key aspects: 1. Water cations are chiefly composed of Ca²⁺ and Na⁺, while groundwater anions are notably NO₃⁻ and SO₄²⁻ dominant, defining the water type as NO₃-SO₄-Ca. Conversely, surface water primarily displays HCO₃⁻ and SO₄²⁻ anions, aligning it with an HCO₃-SO₄-Ca water type. 2. The extensive agricultural activities in the region, coupled with the excessive utilization of pesticides, chemical fertilizers, as well as the discharge of domestic sewage, contribute to heightened NO₃⁻ concentrations in groundwater. 3. The water quality assessments indicate that approximately 53% of agricultural water quality meets irrigation standards based on EWQI, with SAR results suggesting around 65.52% suitability for irrigation and Na% findings indicating approximately 55.88% viability for this purpose. Proper water selection tailored to specific conditions is advised to mitigate potential soil salinization risks associated with long-term irrational irrigation practices. Full article