Impacts of multiple reservoirs on hydrological cycle and hydrochemical evolution in a mountainous river basin of the North China Plain.

The petroleum industry faces a growing need for sustainable treatment of sour produced water to prevent the release of toxic hydrogen sulfide (H2S), which poses serious environmental and health risks. Capturing and removing H2S remains a significant economic and environmental challenge, highlighting the importance of advancing effective H2S mitigation technologies. This work evaluated a green, in house material, L-arginine, at varying concentrations as a novel absorbent for H2S removal from both deionized water (DIW) and produced water (PW). The compound was thoroughly characterized and its performance benchmarked against a commercial triazine-based scavenger. The assessment emphasized removal efficiency over different concentrations, contact times, and operating temperatures (25°C and 50°C). L-arginine substantially increased the pH of both DIW and PW, reaching 10 to 11 in DIW and 9 to 10 in PW. Both L-arginine and triazine achieved exceptional H2S removal, sustaining 99 to 100%. Notably, even at 0.1 wt% L-arginine reduced H2S from 990 ppm to ≤ 6 ppm in both water types, while higher concentrations achieved complete removal. Salts in PW (e.g., NaCl, CaCl2, etc.) had minimal impact on L-arginine's effectiveness, and its performance remained stable at 50°C, demonstrating resilience to temperature variation. It also showed excellent durability, achieving complete H2S removal within 2h and maintaining levels below detection for at least 4h. Overall, L-arginine emerges as a promising, ecofriendly, and effective alternative absorbent for H2S removal from produced water that rivals or outperforms commercial treatments. By mitigating H2S, L-arginine helps reduce environmental hazards. This work represents the first comprehensive comparison of L-arginine's H2S scavenging performance with a commercial triazine benchmark under varied salinity, temperature, and time conditions.

Inner lakes in irrigation districts serve as critical hydrological nodes for water-salt dynamics in arid and semi-arid regions, with their hydrochemical signatures providing sensitive indicators of regional water quality. This study comprehensively investigated the hydrochemical characteristics and controlling mechanisms of nine representative inner lakes in Ningxia's Qingtongxia Irrigation District under three recharge regimes (ecological water replenishment, irrigation return flows, and mixed sources). Combining hydrochemical analysis (Piper and Gibbs diagrams, ionic ratios) with principal component analysis (PCA), key findings revealed that: ① Inner lake waters were weakly alkaline (mean pH of 8.9 ±0.3) and brackish [mean total dissolved solids (TDS) concentration of (1.3±0.7) g·L-1], dominated by Na+ (51%) and SO42- (46%). Pronounced seasonal variations were observed, with summer irrigation period (July) showing 20% and 50% higher ionic mass concentrations than spring (May) and post-autumn (October) periods, respectively. ② Recharge regimes significantly influenced hydrochemical characteristics of inner lakes. Comparative analysis revealed that lakes fed by irrigation return flows and mixed sources showed significantly higher TDS (P<0.05) relative to ecological-water replenished lakes. The total ionic mass concentration in irrigation-fed lakes was approximately double that observed in ecological-water replenished lakes. Within the irrigation district, SO4·Cl-Na water types predominated in the inner lakes recharged by irrigation return flows and mixed sources, while ecological-water replenished lakes displayed mixed Cl-Ca·Mg and SO4·Cl-Na water types. ③ Both natural processes (evaporation-crystallization and rock weathering) and anthropogenic activities drove the hydrochemical evolution of the lake water. The anthropogenic activities were quantitatively assessed through principal component analysis, revealing that human activities accounted for 77.0% of the observed hydrochemical variations. The major anthropogenic sources were identified as: pesticide application/livestock and poultry farming/industrial wastewater (33.1%), nitrogen fertilizer/pesticide application (20.4%), potassium fertilizer application (12.3%), and ecological water replenishment (11.2%). These findings demonstrate that human activities predominantly control lacustrine hydrochemical variability within the irrigation district, providing a scientific basis for precision water-salt management and ecosystem rehabilitation in irrigated areas.

Groundwater and surface quality in the hard rock terrain of the Perambalur district, southern India, were assessed using collected 40 samples during October 2024, representing the integrated hydrochemical, health risk, drinking and irrigation suitability, and hotspot evaluation for this region. Physicochemical parameters (pH, EC, TDS, major, and minor ions) were analyzed for water suitability and health risk assessment. Although pH (6.58-8.24), Ca (3.8-158.9mg/L), and K (1.07-10.69mg/L) are within safe limits, exceedances were observed for TDS (65%, > 500mg/L), total hardness (12.5% > 600mg/L), fluoride (15% > 1.5mg/L), and nitrate (47.5% > 45mg/L). Hydrochemical facies indicate Ca-Cl (82%) and Ca-HCO3 (12.5%) water types, confirming that mineral weathering is the primary geochemical control, with secondary influences from evaporation and anthropogenic inputs. Multivariate analyses (PCA, correlation, HCA) further reveal strong positive loading of fluoride and nitrate on contamination components. The drinking water quality index shows that 95% of samples are suitable for drinking (DWQI < 100), while 5% falls in the poor category (DWQI > 100). Irrigation indices demonstrate that SAR (0.41-5.83meq/L), RSC (-11.4-(-0.26meq/L), Na% (9.86-59.58%), PI (22.85-73.15%), and EC (45.8-2730 µS/cm) are acceptable for irrigation, whereas KR (37% > 1) and MH (55% > 50) indicate sodium and magnesium hazards in localized zones, which may impact soil structure and permeability under prolonged use. Health risk assessment identifies ingestion as the dominant exposure pathway, with the highest total hazard index (THI) for infants (25% > 1), children (25% > 1), and adults (0%), primarily driven by nitrate and fluoride exposure. Spatial analysis highlights fluoride hotspots in the central-northeastern regions and nitrate hotspots in the central-eastern region, where the combined hazard index exceeds the safe threshold (> 1). The study finds the urgency of sustainable groundwater management, optimized fertilizer application, and continuous monitoring to mitigate geogenic and anthropogenic contamination risks and protect public health.

In our study, we have successfully established an analytical method capable of simultaneously detecting six key MPs in drinking water: polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and polyvinylchloride (PVC), employing stainless steel membrane filtration to enrich the MPs in drinking water, and using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) for qualitative and quantitative analysis of characteristic fragment ions produced after high-temperature pyrolysis. And the characteristic fragment ions for MPs are as follows: PMMA(100, 69, 41), PP(126, 70, 55), PVC(128, 127, 102), PET(182, 105, 77, 51), PE(82, 96) and PS(117, 91, 207). By optimizing the key instrument parameters and pretreatment steps, a wide linear range, a relatively low LOD of 0.012-0.40 µg L-1, and a limit of quantitation (LOQ) of 0.039-1.32 µg L-1 were ultimately achieved. The average recovery rate and relative standard deviation (RSD) were 69.73-111.21% and 2.78-12.56%, respectively. The method was applied and verified in the detection of 34 actual samples in different types of water, including groundwater, tap water, and bottled water. This study provides a solution for the quantitative detection of key MPs in drinking water.

ESKAPE pathogens contribute largely to antibiotic resistance spread via horizontal gene transfer in aquatic environments.

Magnetic solid phase extraction with a sorbent nanocomposite made of magnetic nanoparticles (MNPs) embedded in a commercial styrene-divinylbenzene polymeric sorbent (ExtraBond EBH™) is proposed, for the first time, in the extraction and preconcentration of four sulfonamides from different types of water. The importance of using commercial sorbents is that it avoids tedious and complicated synthetic processes and enables intercomparison and harmonization of results. The extraction was carried out with 4mg of nanocomposite, and assisted by sonication for 1min. The back-extraction was with 200μL of methanol for 1min by sonication, too. The subsequent determination was by liquid chromatography and ultraviolet detection. The limits of detection and quantification were 1.4-3.8μgL-1 and 4.8-12.6μgL-1, respectively, with enrichment factors from 5.8 to 13.9. The method was applied to tap and river waters with different salinity and organic matter. The method was considered safe and green enough as well as practical by recently published metrics.

Thermo-structural investigations on Beryl using Vibrational Spectroscopy and X-Ray Diffraction techniques.

Type of water and sanitation facilities and risk of non-partner sexual violence: A multilevel analysis across 31 low- and middle-income countries.

From wells to waves: Evaluating fecal contamination sources using FIB and MST markers along Texas coastal waters.

Rapid detection of ibuprofen in water using wavelet-based hyperspectral imaging.

Surface water and groundwater suitability assessment for drinking and irrigation in a coal-mining area of southwestern China: EWQI, IWQI, and sensitivity analysis.

ABSTRACT In the Bengal Basin of Bangladesh, the excessive extraction of groundwater is leading to a continuous decline in water levels in various regions, as well as contributing to water quality issues. Consequently, evaluating the available freshwater resources is crucial, taking into account both quantitative and qualitative factors. A total of 1,802 groundwater samples were collected during both dry and wet seasons, which were analyzed to assess the type and chemical quality of water. These samples were sourced from 901 groundwater monitoring wells, reaching depths of up to 335 m. The sediments are characterized by cyclic deposits primarily consisting of medium to fine sand, silt, and clay. The groundwater is predominantly of the Ca-Mg-HCO3 and Ca-Mg-Cl types, while Na-Cl and Na- HCO3-Cl types are also observed. The evaporation-sedimentation process significantly influences the chemical composition of all samples taken from depths of 50 to 335 m, as well as the interaction between water and rock, which is anticipated for deeper groundwater. The results will assist users, policymakers and stakeholders in identifying potential zones for groundwater across different applications.

Under drip irrigation conditions, the transport pattern of soil water in the root zone directly affects the water use efficiency of crops. The type of soil matrix, initial moisture content, and irrigation water quality jointly determine the hydrodynamic process of water infiltration. However, as a special type of irrigation water, the water movement mechanism of biogas slurry under drip irrigation in soilless cultivation substrates still lacks systematic investigation. In this study, transparent soil column infiltration experiments were conducted using two types of cultivation substrates—organic (coconut coir) and inorganic (desert sand)—under controlled facility conditions. Three initial moisture contents (10%, 15%, and 20%) and two irrigation water qualities (tap water and diluted biogas slurry) were combined to form twelve treatment groups. Soil moisture sensors and visualization techniques were employed to quantitatively analyze the wetting front morphology, vertical and horizontal infiltration rates, wetting ratio, and soil moisture profile distribution under different treatments. The results showed that the initial moisture content significantly influenced the advancement pattern of the wetting front. Higher initial moisture levels promoted the transformation of the wetting front shape from a “semi-pear” form to a “hemispherical” one and reduced the rate of infiltration decline. The coconut coir substrate exhibited stronger vertical infiltration capacity and a central water aggregation characteristic, whereas the desert sand demonstrated a wider horizontal expansion range. Under low and moderate initial moisture conditions, the application of biogas slurry enhanced horizontal water diffusion and improved the uniformity of the wetted zone, with the wetting ratio increasing by more than 6% compared with high moisture conditions. In addition, the power function model provided an excellent fit for the cumulative infiltration process across all treatments (R2 &gt; 0.96), indicating its suitability for describing the water transport process in facility cultivation substrates. This study provides theoretical support for precise water and fertilizer management and the efficient utilization of biogas slurry in soilless cultivation systems.

As a result of Iraq's scarcity of fresh water, there is a need to find alternative, non-traditional irrigation methods and technologies that would increase water use efficiency and reduce the negative impact of salinity on the tomato crop. The experiment was conducted in the field over two consecutive seasons in heavy soil using a drip irrigation system. The study employed two types of irrigation water with different salinity levels (low, symbolized as q1 = 0.8 ds m-1) and high, symbolized as (q2 = 5.8 ds m-1), and added in three ways: Q1 (q1), Q2 (q1, q2), and Q3 (q2). Two levels of organic matter (F2 and F3) were also used, along with a control treatment without the addition of F1. The study aimed to evaluate the effect of alternating fresh and saline water on tomato productivity, as well as to determine the impact and effectiveness of organic fertilizer in mitigating the negative effects of saline irrigation water and improving the chemical and physical properties of the soil. Statistical analysis showed that both irrigation water quality and amendments had a significant effect on the studied properties. The study year did not affect the overall characteristics of the study, but only the water conductivity and weighted diameter. The results showed an increase in water use efficiency, with averages of 20.7 and 21.13 kg ha-1 mm-1. when using fresh water and a high level of organic matter addition, sequentially. The water quality treatment Q2, combined with soil amendment F3, achieved the highest yield compared to the fresh water treatment Q1 combined with a control treatment (F1), reaching 4.321 and 3.993 kg plant-1, respectively. This was achieved while conserving fresh water by 50% when using moderately saline drainage water with added amendments, without a significant decrease in tomato yield. Therefore, this study proposes adopting a strategy of using saline water with medium electrical conductivity as a partial alternative to low-salinity water, while incorporating organic amendments to ensure sustainable production in water-scarce regions.

Relevanceю Rare earth elements in groundwater are considered as indicators of interaction in the water–rock system, data on distribution in a specific hydrogeochemical system expand the understanding of their water migration properties and the possibility of using them to clarify the conditions of groundwater formation. Aim. To expand the database on the hydrogeochemistry of rare earth elements, to identify the features of their presence in a rare occurrence of soda-type fresh groundwater in Eastern Transbaikalia. Object and methods. The rare earth elements content was obtained from data of testing a well in the Gazimur River basin used for water supply. The chemical composition of water was determined at the Institute of Natural Resources, Ecology and Cryology of the Siberian Branch of the Russian Academy of Sciences according to regulatory methods. Trace element analysis was performed by inductively coupled plasma mass spectrometry (ICP MS) at the Institute of Geochemistry SB RAS. The MINTEQ program is used for thermodynamic calculations of migration forms of macro- and micro-components and mineral equilibria. Results. The authors have analysed the obtained data on the chemical composition of the water from the well used for the water supply of the settlement. The soda type of water with a very low magnesium content (less than 0.1 mg/l), as well as a Ca/P ratio of less than 100, were established. This may be one of the reasons for the existing damage to the inhabitants of the Urovsky endemic disease. The distribution of rare earth elements weight concentrations on the graph corresponds to the Oddo-Garkins parity rule. Thermodynamic calculations determined that in the studied manifestation, macro components are present mainly in the form of simple ions, lanthanides are mainly in the composition of carbonate complexes, which may explain their increased content in an alkaline medium. The equilibrium mineral phases are represented by carbonates, hydroxides, oxides, and silicates. The only mineral form of lanthanides are phosphates, which can remove rare earth elements from the aquatic environment. Conclusions. A new manifestation of soda waters in Eastern Transbaikalia was revealed with rare earth elements distribution for fresh groundwater in the hypergenesis zone, corresponding to the Oddo-Garkins parity rule. For a well-founded explanation of the nature of soda water formation and the distribution features of these rare earth elements in the waters, petrological and geochemical studies of the water-bearing rocks are required.

Thermal groundwater resources constitute valuable health-oriented georesources, particularly when integrated into regional strategies for wellness, balneotherapy, and therapeutic tourism. This study presents the first comprehensive and integrated hydrochemical, geospatial, and balneological characterization of thermal groundwater systems in Uruguay, enabling their classification from a medical hydrology perspective and supporting the assessment of their potential use in balneotherapy. Seven thermal groundwater sources located in northwestern Uruguay were investigated, mainly associated with the Guaraní Aquifer System (GAS), together with the singular Almirón spring, which represents a distinct hydrogeological setting. Field measurements and laboratory analyses were conducted to determine physicochemical parameters, major ions, and gases. Hydrogeochemical facies were identified using Piper and Gibbs diagrams, while multivariate statistical techniques, including Principal Component Analysis (PCA) and hierarchical clustering, were applied to discriminate water types and support their balneological classification. The results indicate that most thermal waters associated with the GAS are characterized by sodium–bicarbonate facies, weak to medium mineralization. Dry residue to 180 °C, (311–734 mg/L), and mesothermal to hyperthermal temperatures (36.3–44.5 °C), reflecting deep confined circulation and prolonged water–rock interaction. By comparison, the Almirón spring exhibits a chloride–sodium facies with strong mineralization. Dry residue to 180 °C, (6590 mg/L) and hypothermal (32 °C), consistent with a distinct hydrogeological origin involving crystalline basement and Devonian sedimentary units and reflecting more evolved geochemical conditions. Based on the obtained results, and by analogy with comparable international hydrothermal profiles, the main balneological indications of these waters include musculoskeletal and rheumatic disorders, dermatological disorders, and other emerging indications such as stress, sleep disorders, obesity, and Long COVID. In conclusion, this study reveals the hydrochemical diversity of Uruguay’s thermal groundwater and its possible use in balneology. Future research should focus on controlled clinical and balneological studies to validate specific therapeutic effects.

Dear Editor, We read with interest the article entitled “Association between drinking water type and kidney stone risk in U.S. adults: a cross-sectional analysis of NHANES 2009–2016 data”[1], published in the International Journal of Surgery. This study investigates the association between drinking water type and kidney stone prevalence in a nationally representative sample of U.S. adults. The authors report an inverse association between tap water intake and kidney stone risk, whereas bottled water consumption was not significantly associated with the outcome. Despite these findings, several methodological and interpretative issues warrant further consideration to strengthen the robustness and credibility of the conclusions. First, although the authors adjusted for multiple covariates in multivariable models, control of potential confounding may be incomplete. Key socioeconomic indicators, including educational attainment and household income, were not included in the adjustment strategy. These factors are established determinants of health-related behaviors and may influence preferences for tap versus bottled water[2]. Their omission may result in residual confounding and bias the observed associations. Inclusion of socioeconomic variables in future analyses would enhance internal validity and strengthen the assessment of associations. Second, participants with incomplete covariate data were excluded from the analytic sample. In cross-sectional studies, such complete-case analysis, if not adequately justified, may reduce statistical power by decreasing the effective sample size. More importantly, it may introduce selection bias when missingness is related to participant characteristics or outcomes, rather than occurring completely at random. In addition, missing covariate data were not further examined in sensitivity analyses. We suggest that future studies consider advanced methods, such as multiple imputation, to handle missing data more appropriately, preserve sample size, and yield more precise and generalizable estimates[3]. Third, the study applied K-means clustering to identify drinking water consumption patterns. However, the added value of this unsupervised approach was not clearly demonstrated, particularly given that conventional logistic regression analyses had already shown a dose–response relationship[4]. In addition, K-means clustering is sensitive to the prespecification of cluster number and initial centroids, which may limit result stability and interpretability in epidemiological research[5]. We suggest that the authors provide a clearer justification for the use of clustering methods and their advantages over traditional regression approaches, or explicitly discuss their methodological limitations to improve analytical transparency and rigor. Beyond these methodological considerations, further discussion is warranted regarding the potential for reverse causality. In this cross-sectional study, the exposure of interest, namely drinking water type, may not be independent of the outcome. Specifically, a history of kidney stone disease may influence individuals’ subsequent choices regarding drinking water. Individuals diagnosed with kidney stones are commonly advised to increase fluid intake or to modify their drinking water source. As a result, the reported water consumption patterns may reflect behavioral changes after diagnosis rather than habitual exposure prior to stone formation. This lack of clear temporal ordering may bias the observed associations and should be explicitly acknowledged to avoid over interpretation of the findings. In summary, this study provides useful insights into the association between drinking water type and kidney stone risk in the U.S. population. Addressing the methodological and interpretative issues noted above would strengthen the robustness of the analyses, support clearer causal interpretation, and enhance the study’s overall contribution to the field.

Physicochemical and bacterial contamination pose a significant threat to drinking water quality in Bangladesh, requiring comprehensive analysis. This study investigates the physicochemical and metagenomic quality of drinking water from one of four water treatment plants (WTPs) in Kushtia Municipality, Bangladesh. Water samples (n = 3) from untreated, treated, and supplied water were collected between March 1 and 7, 2025. Thirteen physicochemical parameters were analyzed using traditional methods, while bacterial load was assessed using Plate Count Agar. Microbial diversity was analyzed through metagenomic sequencing of DNA extracted using the DNeasy PowerWater Kit, targeting the 16S rRNA gene (V3-V4 region) on the Illumina MiSeq platform. Alpha and beta diversity were evaluated with Chao1, Shannon, and Simpson indices, and taxonomic and pathway analysis were performed on the Kaiju and Nephele platforms. Water quality was assessed using treatment efficiency metrics, the Water Quality Index (WQI), and the Nemerow Pollution Index (NPI). Results reveal that only three of the physicochemical parameters meet the water quality standards of Bangladesh. The WTP's cumulative efficiency metric was found to be 30.76%. The WQI indicated that all water samples were unfit for drinking. The NPI showed that eight out of thirteen physicochemical parameters significantly contribute to poor water quality. Microbial evaluations revealed high bacterial levels in untreated and supplied water samples. Alpha diversity analysis, using Shannon and Simpson indices, showed no significant differences in bacterial abundance across water types. Beta diversity analysis indicated minimal dissimilarity. Functional profiling suggested the presence of antibiotic resistance-associated pathways, with predicted beta-lactam resistance representing 24.1% in treated water and 25.0% in supplied water. The dominant phyla include Proteobacteria (38% in untreated, 39% in treated, and 42% in supplied). About 75%, 83%, and 67% of the identified bacterial species were found to be pathogenic, antibiotic-resistant, and biofilm-forming, respectively, while 58% were classified as opportunistic pathogens. These results underscore the need for improved water treatment practices and more robust monitoring systems to ensure the population can access safe drinking water.

Sewage water and sludge provide a viable option to meet crop water and nutrient demands in the face of rising climatic stress. Thus, a 2-year field study (2018 and 2019) was conducted to evaluate the effect of sewage water and sludge on soil properties and the growth response of green chili. The experiment comprised nine treatment combinations involving three types of irrigation water: normal water (I 1 ), treated sewage water (I 2 ), untreated sewage water (I 3 ) along with three soil amendments: farmyard manure (FYM) at 25 t ha −1 (SA 1 ), sewage sludge at 25 t ha −1 (SA 2 ), and a mix of sewage sludge at 12.5 t ha −1 + FYM at 12.5 t ha −1 (SA 3 ). Soil-available nutrient status of N, P, and K increased by ˜10%–15%, ˜14%–20%, and ˜13%–18%, respectively, in I 3 and SA 2 . Sewage water and sludge application further improved soil microbial populations, which included actinomycetes, fungi, and bacteria. Concurrently, multivariate analysis of variance (MANOVA) demonstrated a positive influence of irrigation and soil amendments on soil properties. Across both study years, I 3 and SA 2 recorded a higher mean green chili yield, with an improvement of approximately 25% over I 1 and SA 1 . Hence, the findings reveal the feasibility of harnessing sewage water resources as sustainable inputs, advancing both resource efficiency and short-term agricultural sustainability in the region.