Search Results (409)

This study assessed the performance of a rural water supply system. Performance assessment of water supply systems is important to ensure the long-term sustainability of water services. The study addressed a critical gap in assessing performance while accounting for water disruptions and their effects on water quality in nonlinear rural water supply systems. This is critical, especially in rural areas where reliable access to water is limited. A questionnaire survey was conducted to collect data on the reliability and accessibility of the water supply system. Questionnaire responses were analysed using the Statistical Package for Social Sciences version 25. Spearman’s rank correlation was used to determine the relationship between the socio-economic variables and the performance indicators. and the variables. Turbidity, electrical conductivity (EC), total dissolved solids (TDS), and pH were measured in the field. Escherichia coli (E. coli) and total coliforms were analysed using the membrane filtration method. A paired two-tailed t-test was used to determine if there is a significant difference in water quality between the dry and wet seasons. Key performance indicators on reliability and accessibility were assessed by comparing benchmarks. Most households receive an inadequate quantity of water, with 84.3% using less than the recommended basic need of 1500 L per week. Travel distances to the source exceeded the recommended benchmark of 100 m. The majority of respondents (81.4%) reported frequent water supply disruptions, indicating poor reliability of the source. EC and pH were within the South African National Standards (SANS) 241 guideline for drinking water. TDS, turbidity, and microbial parameters failed to meet safe drinking water standards, except for E. coli during the dry season. There was no significant difference in the water quality between the dry and wet seasons. The water supply system demonstrated poor performance. Measures such as implementing low-cost filtration systems to reduce turbidity, raising community awareness about water safety, and decentralising maintenance activities to improve system sustainability due to financial constraints. These interventions will reduce physical burdens and increase effective water usage. Full article

Mining can significantly affect the spatial distribution and temporal evolution of groundwater chemistry. From July to August 2024, the research team collected 26 surface water and groundwater samples in the Shengli Coal Mine area of the Mongolian Plateau, conducting comprehensive hydrogeochemical analyses on surface water flowing through the mining area, groundwater within the mining area, seepage water, and groundwater outside the mining area. The results indicate that groundwater in this region is notably affected by human activities such as mining operations. Specifically, in surface water flowing through the mining area, concentrations of total dissolved solids (TDS), sulfates, nitrates, and nickel showed significant increases. Compared to groundwater systems in other areas of the Mongolian Plateau, nickel levels in the mining area’s groundwater were significantly higher, while nitrate levels exhibited the opposite trend. A significant positive correlation was observed between metal element concentrations in surface water and groundwater. The study found that abnormal distributions of heavy metals such as beryllium (Be), thallium (Tl), and tin (Sn) may originate from point-source pollution caused by mining activities. Furthermore, concentrations of manganese (Mn), arsenic (As), and antimony (Sb) in the groundwater of this area exceeded relevant regulatory limits, with arsenic being particularly prominent. The levels of arsenic in both surface water and groundwater may pose carcinogenic risks to human health. This study shows that nearly half of the sampled water bodies in the area require purification treatment to meet drinking water standards, highlighting the urgent need for further attention to water quality safety issues. The conclusions derived from this research provide theoretical support for understanding the long-term evolutionary mechanisms of groundwater in mining areas, while also offering important insights for improving groundwater environmental management and ensuring water resource security in mining regions. Full article

Groundwater is an essential freshwater resource in the Western Himalayas, where increasing anthropogenic pressure and environmental variability are raising concerns regarding groundwater quality and water security. However, regionally integrated assessments of groundwater-quality variability across the Western Himalayan states remain limited. This study evaluates groundwater quality across Jammu and Kashmir, Himachal Pradesh, and Uttarakhand using groundwater-monitoring data obtained from the Central Ground Water Board (CGWB). A total of 338 observation wells monitored during 2019–2022 were analyzed using the weighted arithmetic Water Quality Index (WQI) based on Bureau of Indian Standards (BIS) and World Health Organization (WHO) drinking-water guidelines. Spatial and temporal variability were examined through hydrochemical, correlation, and geospatial analyses. The results reveal substantial regional and district-level variability in groundwater quality across the Western Himalayas. Groundwater in Himachal Pradesh and Uttarakhand is predominantly classified as excellent to good, whereas Jammu and Kashmir exhibit greater hydrochemical heterogeneity and localized groundwater deterioration. Elevated WQI values are concentrated within foothill and valley-transition districts, while high-altitude recharge zones generally maintain lower WQI values. Hydrochemical analyses indicate that groundwater-quality variability is primarily associated with mineralization processes, lithological controls, and localized anthropogenic influences. Temporal analysis further indicates moderate groundwater-quality improvement between 2019 and 2022, particularly in parts of Jammu and Kashmir. Overall, the findings demonstrate that groundwater systems across the Western Himalayas remain largely controlled by hydrogeological conditions but are increasingly modified by localized anthropogenic pressures. Strengthened groundwater monitoring, protection of recharge zones, and targeted management of vulnerable foothill and valley-transition environments will be essential for sustaining long-term water security in this climate-sensitive mountain region. Full article

The progressive deterioration of surface water quality due to natural and anthropogenic factors, together with the limitations associated with conventional chemical coagulants, has driven the development of natural coagulants as sustainable alternatives for water treatment. In this context, the present study analyzed the production and application of a chitosan-based natural coagulant obtained from Oreochromis niloticus fish scales through a chemical method. The first phase involved biopolymer extraction through depigmentation, deproteinization, demineralization, and deacetylation; the second phase evaluated its performance as a coagulant using jar tests with water from the Magdalena River; and the third phase consisted of statistical analysis of the results using ANOVA. Yields of 78%, 78.20%, 88.52%, and 30% were obtained for each processing stage, and the chitosan achieved a degree of deacetylation of 76.87%, confirming its potential for water treatment applications. Optimal conditions were determined as a coagulant dosage of 300 mg/L and a flocculation time of 30 min, while ANOVA results indicated that both variables significantly influenced turbidity removal (p < 0.05). Under these conditions, a turbidity reduction of 76.30% was achieved. However, the final turbidity and color values did not meet Colombian regulatory standards, which was attributed to the presence of residual minerals and a moderate degree of deacetylation. Overall, the results demonstrate that chitosan derived from fish scales represents a sustainable alternative to chemical coagulants; however, process optimization and complementary treatment stages are required to meet drinking water standards. Full article

The Wadi Al-Ahsaba watershed is an arid to semi-arid catchment situated in southwestern Saudi Arabia, characterized by intermittent surface flow, high evaporation and low rainfall, and a dam reservoir built for flood control. The work aims to assess hydrological and anthropogenic controls on surface and groundwater quality, pollution status, and human health risks using an integrated approach of hydrogeochemical analysis, multivariable statistics, and water quality and contamination indices. A total of 21 water samples (15 surface water, 6 groundwater) were analyzed for general chemistry, major ions, and trace elements. Hydrogeochemical analysis and principal component analysis (PCA) were implemented to differentiate the geogenic from anthropogenic control on water quality. The pollution status and associated risk were evaluated using water quality index (WQI), contamination degree (Cd), Hazard Quotient (HQ), and Hazard Index (HI). Results suggest limited surface–groundwater interaction, with surface water dominated by Ca–Mg–HCO₃ facies, indicating recent recharge and limited water–rock interaction, whereas groundwater exhibits mixed Ca–Mg–Cl and Ca–Na–Cl–SO₄ types, revealing longer residence time and water–rock interaction. Nitrate (9.5–109 mg/L) and TDS (522–1003 mg/L) exceeded drinking water standards in 90% and 95% of tested samples, respectively, and WQI ranged from 43 to 134, reflecting excellent to poor water. High non-carcinogenic risk from nitrate was observed, especially for infants. The study concluded that the geogenic processes (water–rock interaction, evaporation, and mineral dissolution) control the general chemistry of tested water, while anthropogenic input from wastewater and agriculture input are likely contributors to nitrate contamination. The study contributes to the understanding of arid wadi-dam systems by revealing how limited recharge, hydrological connectivity, and episodic flow control contaminant transport and persistence, underscoring the critical role of integrated hydrological analysis and land use management in safeguarding freshwater resources in arid environments. Full article

This study evaluates the microbiological quality of drinking water in the urban area of Guaranda through an integrated approach combining culture-based methods, biochemical characterization, and polymerase chain reaction (PCR) analysis. A total of 50 drinking water samples were collected from strategically selected points within the urban distribution system following Ecuadorian technical standards. Microbiological analyses included the detection of total and fecal coliforms, as well as the isolation and identification of Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes. Culture-based analyses revealed that 22% of samples were positive for total coliforms and 4% for fecal coliforms. In selective culture media, contamination rates reached 18% for E. coli O157:H7, 8% for Salmonella spp., and 46% for Listeria monocytogenes. However, biochemical profiling showed substantial inconsistencies with the expected phenotypic characteristics of these pathogens, particularly in oxidase and citrate tests, suggesting possible false-positive identifications in complex environmental matrices. PCR assays confirmed lower detection frequencies, identifying E. coli O157:H7 and Salmonella spp. in 2% of samples each, and Listeria monocytogenes in 10% of samples. Agarose gel electrophoresis validated the amplification of specific DNA fragments of 212 bp, 244 bp, and 388 bp, respectively. The findings demonstrate significant discrepancies between conventional phenotypic methods and molecular techniques, highlighting the limitations of culture-based identification when used alone. This study emphasizes the importance of integrating molecular diagnostics into routine water quality monitoring programs to improve the reliability of pathogen detection and support more effective public health risk management in urban drinking water systems. Full article

Brewing water must meet potability standards, as its chemical composition directly affects beer quality and process consistency. Understanding spatial and temporal variability in water composition is essential for quality control and risk management in brewing. This study evaluated the spatiotemporal variation of six key brewing parameters (pH, calcium, magnesium, sodium, chloride, and sulphate) in the Basque Country (Spain) from 2019 to 2023. A comprehensive dataset of drinking water analyses from multiple municipalities was assessed using spatiotemporal analysis tools to identify trends, variability patterns, and potential deviations from recommended brewing water ranges. Water composition showed notable spatial variability, while temporal fluctuations were generally limited. Most parameters remained within recommended ranges for brewing. However, isolated exceedances were identified for sulphate (two municipalities) and sodium (one municipality), representing less than 0.06% of the total records. These deviations may affect flavor profiles and process stability if not properly managed. The findings highlight the importance of continuous monitoring of source water to ensure consistent brewing quality, despite limitations associated with heterogeneous monitoring practices and multi-year data aggregation. The proposed spatiotemporal approach supports risk-based decision-making for brewery location, contributing to improved quality control in the brewing industry. Full article

Tree-based machine learning (ML) models offer a powerful classification framework for rapidly screening groundwater for heavy metal contamination and associated health risks. This study applies several tree-based algorithms to classify groundwater samples from the Jamshedpur Township area, Jharkhand, India, as safe or unsafe with respect to selected heavy metals, using physicochemical parameters as predictors and WHO/BIS limits as class thresholds. Groundwater samples collected from shallow and deeper wells were analyzed for pH, EC, TDS, and heavy metals such as As, Pb, Cd, Cr, Ni, Cu, Zn, Fe and Mn, and compared with drinking water standards to define binary class labels. Groundwater samples were classified into safe and unsafe categories based on WHO/BIS standards and health risk thresholds (HI > 1, CR > ${10}^{-4}$). Health risk assessment indicated significant non-carcinogenic and carcinogenic risks, particularly among children. Decision Tree, Random Forest, Gradient Boosting, and an Optimized Forest-type ensemble were trained and evaluated using accuracy, precision, recall, F1-score, and ROC–AUC, supported by confusion matrices. The Optimized Forest and Random Forest models yielded the highest classification performance, achieving high recall for unsafe samples, which is critical for public health screening, while feature importance analysis highlighted EC, TDS, pH, and specific ions as key predictors. The results indicate that tree-based ML models using routinely measured water quality parameters can serve as efficient decision-support tools for rapid identification of heavy metal risk zones in Jamshedpur Township and similar industrial urban environments. Full article

This study presents a short-term, IoT-enabled sensor-based assessment of treated municipal water and decentralized groundwater in Bragança, northeastern Portugal. Two drinking-water supply contexts were compared: treated surface-water-derived municipal water from the public supply system and groundwater from a decentralized supply system serving part of a higher education campus. Five sampling points were monitored during three campaigns between January and March 2026. At each point, pH, electrical conductivity, temperature, oxidation–reduction potential, and total dissolved solids were recorded at 10 s intervals over approximately 10 min monitoring windows using a multiparameter probe integrated into an IoT-enabled data acquisition workflow. Microbiological analyses were performed on groundwater samples as complementary information. Treated municipal water showed lower mineralization, narrower parameter ranges, and higher oxidation–reduction potential, reflecting source-water characteristics, treatment, and operational control. Groundwater showed higher mineralization, lower oxidation–reduction potential, and greater variability among sampling points and campaigns, consistent with stronger local hydrogeochemical and operational influences. The repeated short-interval readings provided more detailed physicochemical profiles than isolated spot measurements, although the short monitoring windows do not represent continuous long-term high-frequency monitoring. Overall, the results support standardized IoT-enabled sensor-based monitoring as a complementary tool for short-term water-quality assessment and indicate the need for longer seasonal datasets and laboratory confirmation. Full article

Heavy metal(loid) contamination in shallow groundwater poses increasing risks to drinking water safety and human health in agricultural plain areas. In this study, 39 shallow groundwater samples collected from rural wells in Huaiyuan County, northern Anhui Plain, China, were analyzed for seven heavy metal(loid)s (Cr, Mn, Co, Ni, Zn, As, and Mo). The mean concentrations followed the order Mn > Ni > Cr > Zn > Mo > As > Co, and all elements exhibited high spatial variability (CV > 100%). Exceedances of the Chinese Class III groundwater quality standard were observed for Cr, Mn, Ni, As, and Mo, with Ni (43.6%) and Mn (38.5%) showing the highest exceedance rates. Multivariate statistical analyses revealed that groundwater heavy metal(loid)s were mainly controlled by two dominant factors: (i) a transition-metal enrichment factor related to lithogenic background and diffuse anthropogenic disturbance, and (ii) a localized factor controlling the co-occurrence of As and Mo. Human health risk assessment indicated that Co and Mo were the major contributors to non-carcinogenic risk, whereas As dominated the carcinogenic risk. Monte Carlo simulation showed that children faced the highest non-carcinogenic risk, with a mean HI exceeding the safety threshold and an exceedance probability of 28.2%. For carcinogenic risk, As posed a substantial threat, and the exceedance probabilities of total carcinogenic risk reached 67.8%, 66.1%, and 37.0% for adult females, adult males, and children, respectively. These findings demonstrate that shallow groundwater in the study area is affected by both natural hydrogeochemical processes and localized external disturbance and that As, Co, and Mo should be prioritized in groundwater risk management. Full article

Damage to urban water supply infrastructure can rapidly compromise access to safe water and force households to rely on alternative sources of uncertain quality. This study presents a case-based assessment of water quality and emergency household-level treatment options in Mykolaiv, Ukraine, following conflict-induced disruption of the centralized water supply system. Water samples collected from selected groundwater and distribution-network points were analyzed for physicochemical, organoleptic, and microbiological indicators, including total dissolved solids, hardness, sulfates, chlorides, iron, permanganate oxidizability, total microbial count, and E. coli. The results showed elevated mineralization, increased sulfate and chloride concentrations, high hardness, organic load indicators, and episodic microbiological contamination in several samples. A low-cost four-stage household treatment procedure combining chemical oxidation, thermal treatment, sorption, and short-term preservation was evaluated as a preliminary emergency approach. The procedure improved odor, taste, hardness, iron content, permanganate oxidizability, and microbiological safety; however, it did not fully reduce total dissolved solids, sulfates, or chlorides to drinking-water standards. Therefore, the treated water should be considered non-potable and suitable mainly for limited domestic and hygienic uses unless additional desalination or blending is applied. The study highlights both the potential and the limitations of simple household-level interventions under emergency water supply disruption and emphasizes the need for decentralized treatment support, monitoring, and long-term infrastructure recovery. Full article

Santiago, Dominican Republic, faces a growing deficit in the supply of drinking water. Rainwater harvesting systems have the potential to provide a reliable and sustainable source of drinking water. This research examines water quality from the pilot testing of a rainwater harvesting system designed to directly capture rainwater in planter boxes, pre-filter it and store it. The pilot testing consisted of a field experiment comparing rainwater harvested with four filter media compositions with varying levels of sand (34, 62, 66 and 76%). From May 2024 to May 2025, bi-weekly water samples were tested for physicochemical and microbiological parameters including pH, electrical conductivity, total dissolved solids, turbidity, biochemical oxygen demand, heterotrophic bacteria, total and fecal coliforms, E. coli, and Enterobacteriaceae. Statistical models were fitted for each water quality parameter, using linear mixed-effects models or generalized linear mixed-effects models with a logit link, to evaluate the association between filter unit design and water quality outcomes. Results showed that physicochemical quality met Dominican drinking water standards but infrequently met bacteriological standards. However, filters with higher sand composition produced higher quality water for both physicochemical and microbiological parameters. Additional treatment such as chlorination would reduce bacteria and protect the water during storage. Full article

Heavy metal contamination in agricultural production is a significant public health issue in Mexico, as it directly impacts food safety and population exposure through dietary intake. Available scientific evidence indicates that vegetables and other plant-derived foods can serve as significant exposure pathways for toxic elements such as arsenic, cadmium, lead, chromium, and mercury. The consumption of contaminated foods may contribute to cumulative adverse health effects, including neurological, renal, and reproductive alterations, as well as an increased risk of chronic diseases. In Mexico, risk assessment is further constrained by methodological heterogeneity across studies and by difficulties in translating scientific evidence into concrete regulatory actions. Critically, the national regulatory framework lacks specific standards establishing maximum permissible limits for heavy metals in fresh fruits, vegetables, and grains, despite their central role in the population’s diet. Regulations focus primarily on drinking water quality and selected processed foods, creating a regulatory gap in the direct control of contaminants in crops. The findings underscore the urgent need to strengthen public policies by establishing crop-specific regulatory standards, implementing systematic monitoring programs, and integrating food safety considerations more effectively into environmental, agricultural, and public health policies in Mexico. Full article

To achieve the large-scale, high-value utilization of vanadium–titanium slag (VTS) in the metallurgical industry, this study replaces blast furnace slag (BFS) with VTS to construct a quaternary all-solid-waste cementitious system composed of VTS, BFS, steel slag (SS), and desulfurization gypsum (DG). It systematically investigates the effects of VTS content (0–60%) on the mechanical properties, leaching toxicity, and hydration heat behavior of the system. XRD, TG–DSC, and SEM–EDS techniques are employed to explore the influence of VTS on hydration behavior and microstructural evolution. The results show that when VTS replaces 30% of the BFS (A3, VTS:BFS:SS:DG = 3:3:3:1), the 28-day compressive strength reaches 31.33 MPa. The leaching concentrations of heavy metals in all specimens are far below the standards for drinking water quality. Hydration heat analysis reveals that the incorporation of VTS advances the acceleration period of hydration. The A3 specimen maintains a relatively high heat release rate in the middle and later stages (after 72 h), and its cumulative heat release is significantly higher than that of the system without VTS, revealing the “slow hydration” mechanism of VTS at later stages. The [SiO₄]–[AlO₄] bonds in VTS undergo a depolymerization–repolymerization process. In addition, an appropriate amount of VTS promotes the deposition of hydration products such as ettringite (AFt), C–S–H, and C–A–S–H gels through micro-filling effects and heterogeneous nucleation, thereby improving the microstructure of the system. However, excessive VTS (≥45%) significantly inhibits the hydration reaction and reduces gel formation due to the decrease in highly reactive BFS components and the increased TiO₂ content. This study provides new insights into the resource utilization of VTS in multi-solid-waste cementitious materials. In addition, VTS-based cementitious materials are suitable for practical scenarios with low early strength requirements, such as goaf backfilling. Therefore, future studies should further investigate the long-term sulfate resistance and carbonation resistance of these materials under real application conditions. Full article

Municipal solid waste disposed of in open dumpsites and unlined landfills contaminates groundwater, soils, and air across urban areas of low- and middle-income countries. Nevertheless, impacts across all three environmental media have not been systematically assessed together. We conducted a PRISMA 2020-compliant systematic review of 286 peer-reviewed studies from PubMed, Dimensions, and OpenAlex, applying structured eligibility screening and quality appraisal using an adapted JBI checklist. Heavy metals—lead, cadmium, chromium, and zinc—were the most frequently detected contaminants in leachate and groundwater, commonly exceeding WHO drinking water guidelines by one to three orders of magnitude. Soil contamination by potentially toxic elements was documented at virtually all open dumpsites studied, persisting for decades after site closure. Particulate matter at South Asian MSW sites reached up to 41 times the WHO 2021 annual guideline. Microplastics acting as heavy metal carriers and dumpsite leachate as a source of antimicrobial resistance genes were identified as emerging risks outside standard monitoring frameworks. Non-carcinogenic hazard indices exceeded acceptable thresholds in the majority of health risk studies reviewed. Engineered containment was the strongest predictor of contamination severity across all sites. Phytoremediation, constructed wetlands, and biofiltration showed promise as mitigation approaches. Critical evidence gaps remain for Central Asia, harmonized reporting standards, and longitudinal monitoring data. Full article