Search Results (1,561)

Groundwater is a vital water source for human survival and regulates the hydrological cycle within the uppermost strata. Through the processes of recharge and discharge, as well as solute exchange, it interacts with surface water systems in Zhengzhou, e.g., the Yellow River and the Jialu River. Therefore, systematically assessing its hydrochemical characteristics, driving factors, and health risks is crucial for ensuring the safety of public drinking water and regional development. This study focuses on shallow (45~55 m), medium-deep (80~350 m), deep (350~800 m), and ultra-deep (800~1200 m) groundwater in Zhengzhou City. A descriptive statistical analysis was employed to identify the primary chemical constituents of groundwater at various depths within the study area. Piper diagrams and the Shukarev classification method were employed to determine the hydrochemical types of the groundwater. Additionally, Gibbs diagrams, correlation coefficient methods, ion ratio coefficient methods and chlorine–alkali indices were employed to investigate the formation mechanisms of the chemical components of the groundwater, and the health risks in the study area were evaluated. Results: Ca²⁺ dominates the shallow/medium-deep groundwater, Na⁺ dominates the deep/ultra-deep groundwater; HCO₃⁻ (70~82%) is the dominant anion. Water chemistry shifts from HCO₃-Ca to HCO₃-Na with depth. Solubilisation, cation exchange, counter-cation exchange, and mixed processes primarily govern the formation of the groundwater’s chemical composition in the study area. Nitrate health risk assessments indicate significant differences in non-carcinogenic risks across four population groups (infants, children, young adults, and adults). Medium-depth groundwater poses a potential risk to all groups, while shallow and deep groundwater threaten only infants. Ultra-deep groundwater carries the lowest risk. Full article

Background/Objectives: Fluorides play a well-established role in preventing dental caries, primarily by enhancing enamel resistance and inhibiting demineralization. Drinking water is among the most important sources of systemic fluoride intake. In 1993 and 2007, national analyses of Austrian drinking water revealed fluoride levels below 0.5 mg/L in almost all regions, which is insufficient for effective caries prevention. The present study aimed to re-examine the fluoride concentration in Austrian drinking water. Methods: Drinking water was collected in a total of 1985 Austrian municipalities. Fluoride concentration was measured by a fluoride-selective electrode. Results: The average fluoride concentration in the measured water samples ranged between 0.1 and 0.27 mg/L, depending on the region. The analysis revealed that 98% of the municipal drinking water samples contained fluoride at concentrations below 0.5 mg/L. In almost one quarter of Austrian municipalities, the fluoride levels amounted to less than 0.1 mg/L. The fluoride concentration in the drinking water of one Tyrolean municipality exceeded the recommended threshold. Conclusions: The results of the study reveal that the fluoride concentration in Austrian drinking water is generally too low to provide effective prevention against dental caries, affecting nearly all municipalities. Notably, the drinking water of one municipality reached potentially harmful fluoride levels. These findings could be used as a basis for targeted and individual fluoride supplementation, as well as for national or area-specific guidelines. Full article

Chad, one of the poorest Sub-Saharan Central African countries, has one of the worst global diarrhea burdens. Project 21 seeks to enhance community health in the rural town of Béré, Chad but it is lacking. The study aims to determine diarrhea outcomes and associated factors, such as drinking water, malaria, sanitation and hygiene resources and practices, in Béré. A survey questionnaire was administered by trained community health workers using a random sampling method. The respondents (n = 484) are predominantly Nangtchéré (87%) evangelical (63%) males (88%) aged between 40–59 years old (43%) with secondary school education level (37%) or 8 years of school on average, from nuclear families (78%) with seven members on average, and of medium housing standard (56%). Drinking water treatment, transport and storage (p < 0.001), malaria related factors (p < 0.001), sanitation and hygiene practices (p < 0.001), children diarrhea experience, and treatment (p < 0.001) are predictors of diarrhea outcomes in adults. Also, factors related to drinking water transport, treatment and storage (p < 0.001), malaria (p < 0.001), health advice source (p < 0.001), sanitation and hygiene (p < 0.001), adult diarrhea experiences, and treatment (p < 0.001) are predictors of children diarrhea outcomes. Future interventions targeting the above factors are warranted. Full article

Recent studies suggest that Pb-based ammunition could be an important route of Pb exposure for Indigenous Peoples in tropical rainforests. We analyzed blood lead levels (BLL) and isotopic signatures in 111 humans, 97 wild animals, 81 fish, and potential environmental Pb sources in an Indigenous community in the remote and well-preserved Peruvian Amazon with no history of industrial activity. Median BLL was 11.74 μg dL⁻¹, with BLL ≥ 5 µg dL⁻¹ in 95.8% children <12-yo and 94.5% adults. Pb concentrations in wild animals were 7.00 ± 22.40 mg kg⁻¹ DW in liver, 0.06 ± 0.09 mg kg⁻¹ DW in fish muscle tissues, 17.1 ± 10.8 mg kg⁻¹ in soils and 3.4–3.8 mg L⁻¹ in the main river, although 0.43-0.53 mg L⁻¹ were the Pb levels in decanted water used for drinking and cooking. The similarity of isotopic signatures (^207/206Pb and ^208/206Pb) shows that the main Pb sources for humans are river waters (97.6%) and Pb-based ammunition (78.7%). Fish and wildlife act as Pb transporters from water, and wildlife act as Pb transporter from ammunition. Evidence of high human BLL in a remote, non-industrialized Amazonian area demonstrates the urgency of designing regional policies that include health prevention measures, focused on drinking water filtration systems and the use of non-toxic, Pb-free ammunitions. Full article

In Mexico, 95% of the population has access to drinking water sources, but only about 65% of domestic waste water is treated to safe levels. This study analyzes forty years of Mexican scientific production on water and waste water treatment through a bibliometric and conceptual approach, evaluating its contribution Sustainable Development Goal (SDG) 6. The analysis identified three major research clusters: (1) biological processes for water treatment, (2) development and optimization of physical–chemical processes, and (3) water quality and management. These themes reflect the evolution of biological approaches for identifying and removing organic contaminants, the application of advanced techniques for improving water quality, and the promotion of sustainable water use. The study also highlights the growing attention to emerging contaminants, nanotechnology, integrated water resource management, and persistent challenges in sanitation. With respect to SDG 6, Mexican research has mainly focused on targets 6.1 (universal and equitable access to drinking water), 6.3 (water quality), and 6.5 (water resources management), while targets 6.2 (sanitation), 6.a (international cooperation), and 6.b (community participation) remain underrepresented compared with the international benchmarks, where the research trend is on water management, resources, and the water–food–energy nexus. Finally, the findings also show synergies with SDGs 11 (sustainable cities and communities), 9 (industry, innovation, and infrastructure), and 3 (good health and well-being), although gaps persist in addressing equitable access to water and society participation. Full article

Harmful algal blooms (HABs) are an escalating global concern due to their increasing frequency, duration, intensity, and geographic spread. These events threaten public health by contaminating drinking water sources, recreational areas, and food production systems with cyanotoxins. Effective monitoring is critical but remains limited by the spatial and temporal variability of blooms. Unmanned aerial vehicles (UAVs) have recently emerged as a flexible, high-resolution tool for HAB monitoring that can complement satellite and in situ methods. This review synthesizes recent applications of UAVs in HAB detection, mapping, and sampling, with a focus on how these approaches can support public health interventions. Key UAV platforms, sensor types, and data processing workflows are summarized, along with considerations related to flight regulations. Studies linking UAV data to indicators like chlorophyll-a and phycocyanin are discussed, highlighting their relevance for early warning systems and water treatment responses. Finally, the review identifies persistent challenges—including validation, regulatory gaps, and integration with health risk frameworks—and provides recommendations to advance UAV-based monitoring. These insights support the continued development of UAV systems as part of comprehensive strategies to mitigate HAB-related health risks. Full article

This study investigates the paradoxical water security challenges in western Chilean Patagonia, where the regional abundance of water resources masks significant vulnerabilities of drinking water systems. We conducted an integrated socio-hydrological analysis over rural (APR) and urban (APU) drinking water systems, which provide water to approximately 846,000 people. We georeferenced 343 drinking water intake points, from which 51.6% are sourced from groundwater, and 45.8% from surface waters (2.6% other sources). An eco-hydrological characterization was conducted on the 147 watersheds supplying water to the surface intake points. Watersheds were characterized by their main hydrological, morphological, and land cover features, as well as by their level of anthropization (AI) and water stress index (WSI). Social dimensions were captured through structured interviews with 117 APR directorate leaders regarding their perceptions of infrastructure, governance, climate change, and local water management challenges. Our findings suggest that water availability in Patagonia creates a mirage of water security. AI and WSI indicate high variability in the status of water sources, with 25% of watersheds showing high levels of anthropization and 33% with medium to high levels of water stress, making it relevant to explore the results through a combination of hydroclimatic, longitudinal, and latitudinal gradients. A novel analysis linking WSI and AI to governance perceptions was conducted, finding significant inverse correlations between WSI and both technical capacity and users’ participation. Despite the region’s evident abundance of water resources, rural communities consistently express concerns regarding supply sustainability, infrastructure deficiencies, insufficient technical support, and climate change risks to current and future water availability, all of which constrain water security in Chilean Patagonia. Full article

We addressed rising drinking water risks in tropical tourism catchments by selecting Sanya as a representative case and developing an integrated 10–16 m remote sensing framework (Sentinel-2, GF-1) with a fuzzy evaluation, combining NDVI, WET, and NDBSI, K–T + NDVI eutrophication mapping, and event-sensitive RUSLE (30 m DEM, nonlinear LS, monthly NDVI-driven C, localized R). Land use mapping shows orchards at 736.46 km² (38.37%) and tourism land at 2.64% (mostly golf), with 86.52% overall accuracy (Kappa 0.84). Basin-wide, 91% of the area experiences slight–mild erosion, intensified near reservoirs; relative to forests (FVC > 80%), orchards (FVC 60–70%) have a 3.2× higher median erosion risk (IQR 2.8–3.6, 95% CI 2.7–3.7). On 10–25° slopes during flood seasons, orchard pesticide/nutrient runoff indices rise 28–46%, and in the Dalong watershed, high-erosion orchard pixels co-locate with pesticide residues by 62% (95% CI 58–66%). Tourism is associated with elevated nearshore chlorophyll-a (Chl-a); the area is generally mesotrophic (0.25–0.75 mg/L), with localized nearshore hotspots > 1.0 mg/L; across monthly composites, nearshore Chl-a exceeds center waters by 130–210%, and in the Dalong Reservoir, the shoreline-to-center ratio is 2.3–3.1 (median 2.7, 95% CI 2.1–3.3) during 2023–2024 flood seasons. Overall, this source-to-sink framework supports forward-looking governance of drinking water sources under dual monsoon and tourism pressures. Full article

The emergence of microplastics (MPs) in drinking water supply systems has become a significant environmental challenge. Although the potential impacts of MPs in drinking water on human health remain incompletely understood, the ingestion of MPs through drinking water has raised substantial public concern regarding health risks. This review synthesizes contemporary scientific advances focusing on the following: I. the sources and fate of MPs in drinking water supply chains; II. comparative assessment of removal at treatment; III. detection techniques based on microscopy, spectroscopic, and thermal methods; and IV. the potential hazards of MPs to human health. This study aims to provide novel insights into understanding the threats posed by MPs in drinking water and to facilitate the development of effective monitoring strategies. Full article

The widespread presence of estrogens in aquatic environments represents a One Health concern, as it simultaneously threatens environmental integrity, wildlife health, and human well-being. These compounds, widely used in human and veterinary medicine, are excreted in partially or unmetabolized forms and persist in the environment due to the inefficiency of conventional water treatment systems in removing them. This systematic review provides a global overview of the occurrence of estrogens in water resources. We synthesized data on study characteristics, estrogen compounds detected, their concentrations, types of water bodies, and geographic locations. In total, 39 estrogens, including natural, synthetic, and metabolite forms, were reported at concentrations ranging from 0.002 to 10,380,000.0 ng/L across 40 water body types in 59 countries on all continents. The most frequently detected compounds were estrone, estradiol, and ethinylestradiol. Estrogens were predominantly identified in wastewater treatment plant effluents, rivers, lakes, surface waters, and even drinking water sources. These findings underscore the estrogen contamination and its potential to disrupt endocrine functions across species, posing serious implications for ecosystems. Within the One Health framework, this review highlights the urgent need for integrated strategies to improve water quality monitoring, develop advanced treatment technologies, and update regulatory standards to address the multifaceted risks posed by estrogenic contaminants. Full article

Access to safe drinking water is a critical public health priority, particularly in arid regions such as Saudi Arabia where water scarcity and reliance on desalination present unique challenges. This study was conducted to evaluate the quality of drinking water in Madinah City and to examine the potential influence of the distribution system on water quality before it reaches consumers. Water samples were systematically collected from both primary and secondary reservoirs as well as from points within the distribution network. The samples were analyzed for key physical parameters, inorganic constituents, heavy metals, volatile organic compounds, and microbiological indicators using standard laboratory procedures. The results demonstrate that Madinah’s drinking water meets national and WHO drinking water quality standards, with most parameters well below the maximum contaminant levels (MCLs). Slight variations were observed between the primary and secondary reservoirs, likely due to the blending of desalinated seawater with groundwater. Importantly, six heavy metals—iron (115 µg/L), aluminum (48.5 µg/L), copper (58 µg/L), lead (0.22 µg/L), magnesium (7.15 µg/L), and strontium—were detected at higher concentrations in the distribution system compared to the reservoir sources (15, 15, 8.5, <0.05, and 0.71 µg/L, respectively). Although these values remained within acceptable limits, their presence suggests potential leaching from distribution pipes and underscores the need for continuous monitoring. This study provides an evidence-based assessment of water quality in Madinah, offering valuable insights for water authorities to strengthen monitoring programs and ensure long-term protection of public health. Full article

Access to clean drinking water is crucial for any region’s social and economic growth. However, rapid urbanization and industrialization have significantly deteriorated water quality, posing severe pollution threats from domestic, agricultural, and industrial sources. This study presents an innovative framework for assessing water quality in North Bhubaneswar, integrating the Water Quality Index (WQI) with statistical analysis, geospatial technologies, and machine learning models. The WQI, calculated using the Weighted Arithmetic Index method, provides a single composite value representing overall water quality based on several key physicochemical parameters. To evaluate potable water quality across 21 wards in the northern zone, several key parameters were monitored, including pH, electrical conductivity (EC), dissolved oxygen (DO), hardness, chloride, total dissolved solids (TDSs), and biochemical oxygen demand (BOD). The Weighted Arithmetic WQI method was employed to determine overall water quality, which ranged from excellent to good. Furthermore, Principal Component Analysis (PCA) revealed a strong positive correlation (r > 0.6) between pH, conductivity, hardness, and alkalinity. To enhance the accuracy and reliability of water quality assessment, multiple machine learning models Logistic Regression (LR), Decision Tree (DT), Random Forest (RF), Support Vector Machine (SVM), K-Nearest Neighbors (KNN), and Naïve Bayes (NB) were applied to classify water quality based on these parameters. Among them, the Decision Tree (DT) and Random Forest (RF) models demonstrated the highest precision (91.8% and 92.7%, respectively) and overall accuracy (91.7%), making them the most effective in predicting water quality and integrating WQI, machine learning, and statistics to analyze water quality. The study emphasizes the importance of continuous water quality monitoring and offers data-driven recommendations to ensure sustainable access to clean drinking water in North Bhubaneswar. Full article

Micro- and nanoplastics (MNPs) are becoming an increasingly common environmental pollutant. They have been detected in fruit, vegetables, drinking water, seafood, meat, dairy products, and cereals, with particularly high levels often being found in processed foods. The presence of MNPs varies significantly depending on the type of food, geographical region, method of food preparation, and packaging materials used. Of the three main routes of human exposure to MNPs, ingestion is the most important. This article provides a comprehensive review of food contamination by MNPs, including an assessment of the impact of various factors on the MNP abundance. For the first time, it also evaluates the differences in MNP intake among individuals following three typical European dietary patterns: the Mediterranean, Western, and lacto-ovo-vegetarian. The lacto-ovo-vegetarian diet was found to result in the highest MNP intake (69.1 × 10⁶ particles/day), almost doubling that of the other tested patterns. This is mainly due to the very high proportion of fruit, vegetables, legumes, and nuts in daily meals. Taking into account both health concerns and MNP quantity consumed with meals (37.5 × 10⁶ particles/day), the Mediterranean diet is the healthiest. The review also highlights the need to raise awareness of food-related sources of MNPs. Full article

Cyanobacterial blooms are increasingly becoming more intense and frequent, posing a public health threat globally. Drinking water treatment plants that rely on algal bloom-affected waters may create waste (water treatment residuals, WTRs) that concentrates contaminants. Source waters may contain harmful cyanobacteria, cyanophages (bacteriophages that infect cyanobacteria), and bacteria. Cyanophages are known to affect bloom formation and growth dynamics, so there is a need to understand viral-host dynamics between phage and bacteria in these ecosystems for managing cyanobacteria. This study isolated and characterized lytic cyanophages from WTRs of a HAB-affected lake in Ohio that infect toxic bloom-forming filamentous cyanobacteria Planktothrix agardhii. Phage infections in the Lake Erie cyanobacteria culture were examined visually and via microscopy and fluorometry. Whole genome sequencing and metagenomic analyses were also conducted. Observed changes in Planktothrix included sheared and shriveled filaments, reduced clumping, and buoyancy changes. Photosynthetic pigmentation was unexpectedly more apparent during phage infection. Metagenomic analyses identified nineteen phages and seven other co-existing bacterial genera. Annotated bacterial genomes contained metabolic pathways that may influence phage infection efficiency. Viral genomes were successfully tied to microbial hosts, and annotations identified important viral infection proteins. This study examines cyanobacterial-phage interactions that may have potential for bioremedial applications. Full article

This study investigates the presence of pesticides in rivers in Chile’s Central Valley, taking a socioecological approach that seeks to create a dialogue between scientific analysis and community perceptions of those who live in rural territories. Exploratory sampling was carried out in three river basins in the Maule and Ñuble Regions (Putagán-Loncomilla, Ñiquén and Changaral rivers) during the southern summer of 2024. Samples were tested for 535 pesticides using gas and liquid chromatography techniques coupled with mass spectrometry. Diuron was quantified in the Putagán-Loncomilla and Ñiquén basins (≥LOQ = 0.01 mg/L), with concentrations in some cases exceeding international drinking water standards. Fosetyl-Al and its degradation byproduct, phosphonic acid, were also quantified in all samples analyzed. These findings confirm the persistence of certain agrochemicals in aquatic ecosystems and reveal the need for stricter regulations in Chile. This study also highlights the importance of integrating community knowledge in the identification of possible sources of pollution. Continuous monitoring of pesticides in the Central Valley’s rivers is recommended, in addition to a standard regulating their presence in surface waters and the adoption of mitigation strategies to reduce the impacts of pesticides on human health and the environment and further development of sustainable agriculture. Full article