Search Results (1,985)

Riparian land use and land cover (LULC) exerts scale- and season-dependent controls on surface water quality, yet its influence in regulated agricultural–urban rivers is poorly characterized. We combined seasonal t-tests, one-way ANOVA, and redundancy analysis (RDA) at three riparian buffer scales (500, 1000, and 2000 m) to examine discharge, dissolved oxygen (DO), temperature, turbidity, and pH at four USGS stations along the Kansas River mainstem (2019–2026). DO and temperature showed the strongest seasonal contrasts: DO was 3.1–3.7 mg/L higher in the dry season and temperature 13–15 °C higher in the wet season, a coupling central to aquatic habitat suitability. Turbidity rose significantly in the wet season, consistent with agricultural runoff and sediment mobilization, whereas discharge showed no significant seasonal difference at three of four stations, reflecting upstream reservoir regulation. Spatial ANOVA detected station-level differences only for wet-season DO ($F_{3,28}=4.91$, $p=0.007$), which was lowest at the downstream urbanized station. RDA linked agricultural cover to turbidity and urban cover to reduced wet-season DO, although permutation tests were non-significant ($p\ge 0.42$) at $n=4$ replicates. Seasonality and riparian LULC jointly shape water quality along this regulated river, and the 500 m buffer is the most spatially discriminating scale for land-cover assessment. Full article

Recreational coastal waters are increasingly affected by urbanization, maritime activities, and tourism, creating a need for predictive tools that support proactive water quality management. This study proposes an explainable machine learning framework for forecasting near-future changes in the Tourism-Oriented Seawater Quality Index (SeaWQI-T) using high-frequency seawater monitoring data collected in the Gulf of Vlorë, Albania. A summer monitoring campaign (June–August 2025) produced 102,988 physicochemical observations from six monitoring stations using an unmanned surface vehicle equipped with a Horiba U53 multiparameter sonde. Following quality control and temporal aggregation, the data were used to formulate a multiclass forecasting problem (decrease, stable, or increase), and Logistic Regression, Random Forest, and Extreme Gradient Boosting (XGBoost) models were evaluated across multiple forecasting horizons. XGBoost achieved the best validation performance, while Random Forest demonstrated superior generalization on the independent test dataset and provided the most stable explainability results. SHapley Additive exPlanations (SHAP) identified SeaWQI-T dynamics, turbidity, dissolved oxygen, and oxidation–reduction potential as the most influential predictors. The proposed framework demonstrates that integrating explainable machine learning with autonomous high-frequency monitoring can provide accurate, interpretable forecasts to support intelligent coastal recreation management and sustainable tourism planning. Full article

The search and discovery of underwater shipwreck sites represent the most arduous and critical phases of underwater archaeology. Wooden shipwrecks, in particular, are characterized by low acoustic impedance contrast and weak magnetic anomalies, coupled with their limited physical dimensions. Consequently, they predominantly exist as shallow-buried, discontinuous small targets scattered within confined areas, making their detection exceptionally challenging. Furthermore, the complexity of the submarine environment—including rugged topography, turbid water columns, and strong currents—poses formidable obstacles to the effective detection of these archaeological remains. Single geophysical methods are often limited by insufficient imaging resolution, interpretation ambiguity, and geological noise, making precise localization and characterization difficult. Focusing on the Nan’ao I Ming Dynasty shipwreck located in waters approximately 24 m deep off the coast of Nan’ao, Guangdong Province, China, this study proposes and validates an “acoustic-magnetic” multi-source data integration detection method. This approach systematically integrates high-resolution multibeam echo sounding (MBES), side-scan sonar (SSS), sub-bottom profiling (SBP), and marine magnetic data to establish a comprehensive framework for identification and integration analysis. The results indicate that the MBES bathymetric data reveal a regular, elongated structure oriented north–south (approximately 34 m × 12 m), closely matching the main hull and deck configuration. The SSS imagery exhibited high backscatter intensity and parallel linear textures, effectively delineating the hard shipwreck structure and the associated rigid protective frame employed for in situ preservation. SBP data confirmed the semi-buried state of the shipwreck (burial depth of approximately 0.6 m). Spatial variations in sediment thickness around the site suggested ongoing modification by strong hydrodynamic processes. Marine magnetic surveys identified localized negative anomalies (−210 nT relative to the ambient magnetic field), contrasting sharply with the positive anomalies of the surrounding natural reefs, thereby indicating an artificial ferromagnetic source. The spatial registration and feature superposition of multi-source data facilitated the characterization of the shipwreck, demonstrating its potential to mitigate environmental interference and enhance detection reliability in this complex environment. Using the Nan’ao I shipwreck site as a case study, this study provides a detailed characterization of the site’s 3D morphology, burial state, and physical properties. The proposed methodology offers a practical and robust technical solution for underwater shipwreck archaeology in complex nearshore environments, providing significant implications for proactive discovery, efficient investigation, and protection of underwater cultural heritage (UCH). Full article

Lake Sofia, located in the mountains of northern Madagascar (1100 m a.s.l.), has experienced increased sediment loads over the past century, which have adversely affected its biodiversity and reduced its lifespan. Lake Sofia provides critical ecosystem services and is an important habitat for threatened species, e.g., the critically endangered Madagascar Pochard (Aythya innotata). Suggested causes of the high sediment load in Lake Sofia are water erosion, wind erosion, and the stirring of mud from the bottom of the lake by recently introduced tilapia (Oreochromis spp.). Using publicly available weather reanalysis, satellite data, land cover data, soil data, and elevation data, we attribute high turbidity levels in Lake Sofia to water erosion, which explains over 90% of the variance in lake turbidity. Wind erosion was not significant, and tilapia did not contribute to sediment influx. Increased precipitation and decreased vegetation cover in agricultural areas contributed most to increased erosion risk, whereas lavaka (erosion gullies) contributed less. Erosion risk over crop lands has increased by 2% annually and is expected to increase further because of climate change and expected increased precipitation intensity. The erosion model identifies areas most at risk to be targeted for interventions, and is applicable to other catchments in Madagascar and elsewhere. Full article

Rapid urbanization and inadequate sanitation infrastructure threaten water security in many sub-Saharan African cities. This study aimed to provide an integrated assessment of groundwater, surface water, and wastewater quality in Bangui by characterizing physicochemical parameters, trace metals, and microbiological indicators, and by identifying potential contamination sources and pathways among these water compartments. A total of 28 water samples were collected from groundwater, surface water, and wastewater sites. Physicochemical parameters, major ions, trace metals, and microbiological indicators were analyzed using standardized methods, including ion chromatography, ICP-OES, ICP-MS, and membrane filtration. Results revealed a clear contamination gradient. Wastewater showed the highest electrical conductivity, turbidity, chloride concentrations, and microbial loads, reaching 2.41 × 10⁶ CFU/100 mL for total coliforms and 1.93 × 10⁶ CFU/100 mL for fecal coliforms. Groundwater exhibited high nitrite levels and low dissolved oxygen, indicating vulnerability to sewage infiltration. Surface waters were characterized by high turbidity and widespread fecal contamination despite relatively good oxygenation. In contrast, trace metal concentrations generally remained below World Health Organization guideline values. Geochemical analyses identified distinct elemental signatures for each water type. Microbiological contamination emerged as the dominant water quality concern. High fecal coliform/fecal streptococci ratios (13.08-22.16) indicated predominantly human-derived pollution linked to untreated wastewater and inadequate sanitation systems. The association between elevated nitrite concentrations and fecal indicators suggests active contamination pathways connecting wastewater, surface water, and shallow aquifers. These findings highlight the urgent need for improved wastewater management, groundwater protection, and long-term monitoring to ensure sustainable urban water security in Bangui. Full article

Porcelain manufacturing technological wastewater contains many mineral particles, like kaolinite 27%, quartz 29%, calcium feldspar 15%, and mullite 12%. These particulate matters are dispersed into the wastewater from all technological steps influencing the water parameters, such as pH, electrical conductivity, total dissolved solids (TDS) and turbidity. These properties were measured and correlated with the physicochemical investigation of the collected particles. The two sample types are as follows: particles collected directly from the wastewater dispersion (WWS) and the slurry (SLR) collected from the dump. The mineral distribution was assessed by XRD correlated with mineralogical optical microscopy, revealing the relative distribution of the finest kaolinite particles with respect to quartz and feldspar boulder-like particles. Mullite was observed as a rounded inclusion occurring due to the re-circulated grounded material. It results in the presence of sodium silicate, acting as a densification binder when the samples are completely dried. Particle morphology was correlated with their elemental composition through SEM–EDX investigation. Iron hydroxide was found at about 9%. It prevents re-circulation of this wastewater slurry in porcelain production. Thus, a sustainable approach is required for its utilization as a sub-product. Therefore, the samples were subjected to thermal analysis in order to reveal its sintering behavior. Thermal analysis revealed the dehydroxylation of kaolinite between 530 and 630 °C, and a high-temperature thermal event at 994 °C (WWS) and 997 °C (SLR), which was further confirmed by DSC and attributed to mullite formation. Particle consolidation through the dehydroxylated kaolinite matrix and further mullitized mass was assessed through SEM microscopy, indicating proper densification to ensure slurry utilization for less pretentious ceramic products, allowing them to be fired at relatively lower temperature than porcelain (e.g., 600–800 °C) and ensuring a significant energy consumption saving. Full article

Access to clean drinking water is one of the main factors influencing public health during humanitarian crises. In the northern districts of the Gaza Strip, long-term warfare and mass migration caused serious damage to the water supply system, cutting off access to drinking water, limiting the availability of fuel and chemicals used for water chlorination, and increasing reliance on intermittent networks and water transportation services. The present study is a descriptive cross-sectional study of water quality and health risks in 11 emergency camps. Water samples were collected from supply points, communal tanks, and household storage containers and analyzed for key physicochemical indicators (pH, turbidity, electrical conductivity/total dissolved solids, residual free chlorine) and microbiological contamination (E. coli and fecal coliforms). Household surveys documented transport and storage practices, perceived service adequacy, and recent gastrointestinal illness. Overall, 35% of samples exceeded WHO microbiological limits; E. coli was detected in 28% of household containers and 24% of distribution tanks. Residual chlorine was <0.5 mg/L in 40% of samples and turbidity exceeded guidance in 18%. Forty-five percent of households reported transferring water using open/uncovered containers, and 42% reported gastrointestinal illness in the previous month, with higher reporting in sites showing microbial contamination. The results suggest that there are significant weaknesses in the source-to-point-of-use system during emergencies. The priority actions we recommend are, restoring residual disinfection; strengthening monitoring at important control points; improving hygienic transport and covered storage; and providing backup fuel and treatment supplies to minimize the risk of waterborne diseases in shelters in North Gaza. Full article

Flocculation-sedimentation is a widely used solid–liquid separation process in mineral processing and wastewater treatment, yet its optimization remains challenging due to nonlinear interactions among reagents, solids, and operating conditions. This study presents a statistically rigorous multi-response optimization framework combining HuberT robust regression, canonical analysis, and the Derringer desirability function, and demonstrates its application to coal slurry water treatment as a case study. Coal slurry concentration, polyacrylamide (PAM) dosage, and CaCl₂ concentration were used as factors, with supernatant turbidity and initial settling velocity as responses. A central composite design (20 runs) was employed, and second-order models were fitted via HuberT M-estimation to mitigate the influence of potential outliers. Both the ln-transformed turbidity model (R² = 0.9887) and settling velocity model (R² = 0.9908) showed high significance and predictive capability. Canonical analysis confirmed that the turbidity response surface exhibits a true minimum within the design space, while the settling velocity surface has a saddle-point structure. HuberT weight diagnostics identified no downweighted runs for turbidity and two mildly influential runs for settling velocity, confirming overall data consistency. Multi-response optimization via the Derringer desirability function yielded a combined optimum (coal slurry 25.27 g/L, PAM 5.19 mg/L, CaCl₂ 2.07 g/L; desirability D = 0.8981) with predicted turbidity of 29.21 NTU and settling velocity of 13.26 mm/s. The proposed framework may be extended to other flocculation-sedimentation systems requiring simultaneous improvement of multiple, often conflicting, process responses, although this generalizability has not yet been empirically tested beyond the single coal slurry system examined here. Full article

Access to safe drinking water remains a global challenge, particularly in decentralized and low-resource settings where conventional treatment technologies may be economically or operationally impractical. Combining low-energy hydraulic flocculation systems with biodegradable natural coagulants represents a promising strategy for sustainable water treatment. This study investigated the influence of hydraulic retention time (HRT) on the clarification performance of aluminum sulfate, Moringa oleifera, and Aloe vera in continuous-flow helically coiled tube flocculators (HCTFs). Four HRTs (1.71–6.84 min) were obtained by varying reactor length while maintaining a constant flow rate of 0.5 L/min. Synthetic water with an initial turbidity of approximately 100 NTU was treated, and clarification performance was evaluated by residual turbidity and turbidity removal efficiency. Two-way ANOVA revealed significant effects of HRT and coagulant type, as well as a significant interaction between these factors (p < 0.001), indicating that the influence of HRT depended on the dominant coagulation mechanism. Aluminum sulfate maintained consistently high turbidity removal efficiencies (96.3–98.1%) regardless of HRT. In contrast, Moringa oleifera achieved the highest clarification efficiency (99.5%) and a final turbidity of 0.49 NTU at the longest HRT, whereas Aloe vera exhibited the greatest hydraulic sensitivity, with turbidity removal increasing from 78.9% to 96.1% as HRT increased. The results demonstrate that HRT should be selected according to the dominant coagulation mechanism of the coagulant rather than adopted as a fixed design parameter. This mechanism-based approach provides a rational basis for designing and optimizing continuous-flow flocculators and supports the development of compact, efficient, and sustainable decentralized water treatment systems. Full article

Underwater object detection remains challenging in adverse aquatic environments, where severe image degradation caused by turbidity, light scattering, color attenuation, and low illumination substantially reduces detection reliability. Although real-world underwater datasets are essential, their limited scale and environmental diversity make it difficult to cover the wide range of degraded conditions encountered in practice. To improve detection robustness without collecting additional annotations, we propose physics-aware diffusion synthesis (PADS), a framework that uses a small set of labeled real images to synthesize diverse physically plausible degraded underwater samples. PADS couples a ControlNet-conditioned latent diffusion generator with a physics-based underwater image-formation model inspired by Jaffe–McGlamery and Akkaynak optics. Semantic masks are first employed to preserve object layout during generation. Meanwhile, water-optics parameters are incorporated through cross-attention to guide the degradation process. In addition, the physical model enforces a color and attenuation consistency loss during training and serves as an SDEdit-style latent prior during synthesis. To further improve localization under degradation, especially for small objects, we introduce a training-only scale-aware focaler–NWD (SA-FNWD) bounding-box loss, which emphasizes normalized Wasserstein distance for small boxes while retaining IoU-based regression for larger objects. Experiments on the MOUD dataset demonstrate that detectors trained with PADS-synthesized data achieve substantially stronger robustness under severe degradation. At the harshest turbidity level, PADS retains 59.3% of clean accuracy compared with 14.9% for the copy–paste-based synthesis method and 14.1% for the pix2pix-based synthesis method. SA-FNWD further improves mAP@0.5:0.95 across degradation severities. These results show that physics-grounded diffusion synthesis provides the main robustness gain, while SA-FNWD offers a complementary small-object localization improvement with no inference overhead. Full article

Poyang Lake is a typical floodplain lake hydrologically linked to the middle-lower Yangtze River. Its peripheral saucer-shaped sub-lakes undergo seasonal hydrological alternation between isolation and connectivity driven by annual water level fluctuations. To date, the coupling between seasonal hydrological rhythms and zooplankton metacommunity assembly in these saucer floodplain lakes remains poorly understood. In this study, four representative saucer sub-lakes within the Poyang Lake National Nature Reserve (Banghu, Zhonghuchi, Shahu and Dahuchi) were selected as research objects. Seasonal quantitative zooplankton surveys and synchronous hydro-physicochemical monitoring were conducted across four hydrological phases from 2012 to 2013: low-water isolation (spring), high-water connectivity (summer), water recession transition (autumn), and extreme low-water closure (winter). We systematically explored how water level fluctuations regulate zooplankton metacommunity assembly processes. In total, 95 zooplankton species were identified, among which rotifers (68 species) constituted the absolute dominant taxon, and 15 species were identified as year-round absolute dominants exhibiting regular seasonal succession in response to hydrological shifts. Our results demonstrate that hydrological connectivity plays a strong role in regulating the relative strength of species dispersal and environmental filtering. During spring and winter, complete hydrological isolation blocked inter-lake species exchange, making local environmental filtering the main driver of metacommunity assembly. Isolated sub-lakes harbored fewer total species but abundant endemic taxa, accompanied by pronounced spatial community heterogeneity. When water levels exceeded the 17.3 m threshold in summer, full water exchange between sub-lakes and the main lake coincided with widespread species dispersal, which appeared to represent the primary assembly process. The four sub-lakes shared 23 co-occurring species during this period, with highly homogenized community structures and minimal spatial differentiation (Global test: R = 0.47, p = 0.001). In autumn, receding water levels weakened inter-lake connectivity, such that environmental filtering and dispersal jointly structured zooplankton metacommunities; significant spatiotemporal differences were detected in zooplankton density, biomass and α-diversity (p < 0.05). Critical hydro-physicochemical factors of environmental filtering included water temperature, chlorophyll a, pH, electrical conductivity and turbidity, yet the dominant limiting factor varied spatially across sub-lakes due to divergent basin topography and water residence time. Species co-occurrence network analysis revealed that zooplankton communities achieved the highest stability during the fully connected summer phase. In early autumn water drawdown, species association networks became fragmented, and community stability reached its annual minimum. This study elucidates the mechanistic link between floodplain lake hydrological rhythms and zooplankton metacommunity assembly, providing theoretical support and baseline data for wetland biodiversity conservation and ecosystem management of Poyang Lake floodplains. Full article

Urban rainwater is an increasingly important alternative water resource, but its suitability for harvesting and reuse depends on a water quality that varies strongly with local emissions and season—a variability not previously characterised for Bucharest, the Romanian capital. This study addresses that gap by evaluating the physicochemical quality of directly collected rainwater at six contrasting sites (four traffic-influenced, two urban-green) in District 1, Bucharest, over 37 rainfall events sampled between January and November 2025. Samples were analysed for pH, electrical conductivity, turbidity, true colour, total hardness, chloride, inorganic nitrogen species (NO₃⁻–N, NO₂⁻–N, NH₄⁺–N) and trace metals (Zn, Cd, Pb), and interpreted using descriptive statistics, Pearson’s correlation and Principal Component Analysis (PCA). Traffic-influenced sites were consistently more contaminated than urban-green sites, with mean concentrations higher by 47% for electrical conductivity (EC), 64% for cadmium and 67% for zinc. PCA resolved two factors: traffic-related particulate pollution (Cd, Pb, Zn) and secondary atmospheric nitrogen processing. Cadmium reached the World Health Organisation (WHO) indicative guideline, and lead exceeded the European Union (EU) parametric value at traffic sites, while ammonium exceeded 0.50 mg/L in most traffic-site events. These findings show that harvested rainwater quality is strongly site-dependent and that high-traffic locations require targeted treatment before any potable reuse. Full article

The growing demand for sustainable and functional packaging has driven the development of biopolymer-based films prepared from food-grade components with potential suitability for edible packaging applications. This study focused on the development and characterisation of furcellaran/xanthan gum/beeswax composite films enriched with Spirulina biomass and prepared using high-shear homogenisation (HSH). The effect of Spirulina incorporation on the structural, physicochemical, mechanical and morphological properties of the films was evaluated. HSH enabled the dispersion of beeswax and Spirulina within the polysaccharide-based matrix. The FTIR spectra showed absorption bands consistent with polysaccharide-associated vibrations, including 3,6-anhydrogalactose (~930 cm⁻¹) and galactose-4-sulfate (~845 cm⁻¹), and indicated changes in selected functional group regions after Spirulina incorporation. XRD revealed ordered beeswax-related domains, including a reflection corresponding to a d-spacing of about 15.27 Å. Spirulina decreased the contact angle, increased WVTR approximately 2.5-fold and reduced the maximum breaking load, whereas tensile strength and elongation at break remained comparable between formulations. SEM showed a more heterogeneous morphology in Spirulina-containing films, with pores, voids and local biomass clusters. The films exhibited approximately 59% (FUR/XAN/BE) and 47% (FUR/XAN/BE/S) water solubility but formed turbid hydrogels during extraction, preventing reliable direct ABTS and CUPRAC determination. The results indicate potential for edible coatings, although further optimisation and validation are required. Full article

Chlorophyll-a is a widely used indicator for assessing the trophic status and water quality of aquatic ecosystems because of its close relationship with phytoplankton biomass. This study aimed to identify the physicochemical, biological, and temporal variables associated with chlorophyll-a concentrations in Lake Gatun during the 2017–2023 period using the Light Gradient Boosting Machine (LightGBM) algorithm and a Generalized Linear Model (GLM). A total of 25 predictor variables describing water quality were analyzed using data collected from 14 monitoring stations distributed throughout Lake Gatun within the Panama Canal watershed. The LightGBM model achieved satisfactory predictive performance, with an RMSE of 4.58, an MAE of 3.26, and a coefficient of determination (R²) of 0.42 on the testing dataset. Variable importance analysis identified turbidity, dissolved oxygen, and water transparency as the most influential predictors of chlorophyll-a concentrations. These findings improve our understanding of the factors associated with chlorophyll-a variability and demonstrate the potential of machine learning models as decision-support tools for monitoring and managing aquatic ecosystems. Full article

The growing demand for natural, skin-compatible cosmetic cleansers has driven interest in oil-based systems that can effectively remove waterproof cosmetics while remaining physicochemically stable. This study characterized hemp seed oil and evaluated it as a component of a water-in-oil (W/O) microemulsion makeup remover. Hemp seed oil showed good oxidative stability (peroxide value = 1.87 ± 0.23 mEq/kg). It contained 0.134 ± 0.01 mg gallic acid equivalents/g of oil weight of phenolic compounds. The oil was rich in linoleic and α-linolenic acids and contained α-tocopherol. Microemulsions were prepared by combining hemp seed oil with castor oil (C:H) or sunflower oil (S:H) at three oil ratios and four surfactant HLB values (4.3–12). From 72 candidate formulations, only sunflower oil:hemp seed oil systems in the ratio of 3:7 and HLB of 9.5 showed the best overall balance of stability, maintaining droplet size, low PDI, and consistent viscosity/turbidity over 2 months of storage and heating–cooling cycle testing. This formulation also exhibited cleansing efficiency (ΔE = 9.64), which was slightly lower than a commercial cleansing oil (ΔE = 9.74). These results illustrate the potential of hemp seed oil to be developed into a stable, effective W/O microemulsion cleansing system for cosmetic application. Full article