Search Results (22,696)

Deforestation and wildfires drastically impact vegetation cover, consequently affecting water dynamics. These hazards alter the different components of the water cycle, including evapotranspiration, runoff, infiltration, and groundwater recharge. Overall, runoff increases while infiltration and groundwater recharge decrease. Furthermore, these hazards significantly alter the chemistry of both surface water and groundwater. The main changes to water quality relate to turbidity, bacterial load, mineralization and nutrients. Forest fires can also release contaminants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Other contaminants can be introduced by products used in firefighting, such as retardants and perfluoroalkyl substances (PFAS). This paper reviews the impact of deforestation and wildfires on water resources, especially with a view to their use as raw water for drinking water production. The paper identifies the magnitude of the changes induced in water quantity and quality. Even if the results are climate- and site-specific, they provide an indication of the possible magnitude of these impacts. Finally, the various changes brought about by these hazards are ranked according to their potential impact on drinking water production. Full article

Total alkalinity (TAC) plays a pivotal role in buffering acid–base fluctuations and maintaining pH stability in aquatic ecosystems. This study presents a data-driven approach to model TAC using decision tree regression, applied to a comprehensive dataset of 454 water samples collected in diverse aquatic environments of the Médéa region, Algeria. Twenty physicochemical parameters, including concentrations of bicarbonates, hardness, major ions, and trace elements, were analyzed as input features. The decision tree algorithm was optimized using the Dragonfly metaheuristic algorithm coupled with 5-fold cross-validation. The optimized model (DT_DA) demonstrated exceptional predictive performance, with a correlation coefficient R of 0.9999, and low prediction errors (RMSE = 0.3957, MAE = 0.3572, and MAPE = 0.4531). External validation on an independent dataset of 68 samples confirmed the model’s robustness (R = 0.9999; RMSE = 0.4223; MAE = 0.3871, and MAPE = 0.4931). The tree structure revealed that total hardness (threshold: 78.5 °F) and bicarbonate concentration (threshold: 421.68 mg/L) were the most influential variables in TAC determination. The model offers not only accurate predictions but also interpretable decision rules, allowing the identification of critical physicochemical thresholds that govern alkalinity. These findings provide a valuable tool for anticipating pH instability and guiding water quality management and protection strategies in freshwater ecosystems. Full article

The use of reclaimed water is crucial to prevent pollution from wastewater discharges and mitigate the water deficit faced by irrigation districts or other non-potable water users. Therefore, the zero-discharge strategy represents a significant challenge for coastal cities affected by marine pollution from effluents. In regions such as the Mediterranean arc, agricultural areas located near these cities are increasingly exposed to reduced water allocations or rising irrigation demands due to the impacts of climate change. To address this dual challenge, a circular system is proposed through the implementation of hybrid treatment technologies that enable zero wastewater discharge into the sea. This approach would contribute up to 30 hm³ of reclaimed water annually for irrigation, covering approximately 27,000 hectares of cropland in the province of Alicante. The proposed system integrates advanced techniques, such as reverse osmosis, to ensure irrigation water quality, while also considering partial blending strategies to optimize resource use. Additionally, constructed wetlands are incorporated to regulate and treat the reject streams produced by these processes, minimizing their environmental impact. This combined strategy enhances water reuse efficiency, strengthens agricultural resilience, and provides a sustainable model for managing water resources in coastal Mediterranean regions. Full article

Rapid sand filtration is a critical step in the water treatment process, as its effectiveness directly impacts the supply of safe drinking water. However, optimising filtration processes in water treatment plants (WTPs) presents a significant challenge due to the varying operational parameters and conditions. This study applies explainable machine learning to enhance insights into predicting direct filtration operations at the Ålesund WTP in Norway. Three baseline models (Multiple Linear Regression, Support Vector Regression, and K-Nearest Neighbour (KNN)) and three ensemble models (Random Forest (RF), Extra Trees (ET), and XGBoost) were optimised using the GridSearchCV algorithm and implemented on seven filter units to predict their filtered water turbidity. The results indicate that ML models can reliably predict filtered water turbidity in WTPs, with Extra Trees models achieving the highest predictive performance (R² = 0.92). ET, RF, and KNN ranked as the three top-performing models using Alternative Technique for Order of Preference by Similarity to Ideal Solution (A-TOPSIS) ranking for the suite of algorithms used. The feature importance analysis ranked the filter runtime, flow rate, and bed level. SHAP interpretation of the best model provided actionable insights, revealing how operational adjustments during the ripening stage can help mitigate filter breakthroughs. These findings offer valuable guidance for plant operators and highlight the benefits of explainable machine learning in water quality management. Full article

Unmanned aerial vehicle (UAV) hyperspectral remote sensing imaging systems have demonstrated significant potential for water quality monitoring. However, accurately obtaining water-leaving reflectance from UAV imagery remains challenging due to complex atmospheric radiation transmission above water bodies. This study proposes a method for water-leaving reflectance inversion based on air–ground collaborative correction. A fully connected neural network model was developed using TensorFlow Keras to establish a non-linear mapping between UAV hyperspectral reflectance and the measured near-water and water-leaving reflectance from ground-based spectral. This approach addresses the limitations of traditional linear correction methods by enabling spatiotemporal synchronization correction of UAV remote sensing images with ground observations, thereby minimizing atmospheric interference and sensor differences on signal transmission. The retrieved water-leaving reflectance closely matched measured data within the 450–900 nm band, with the average spectral angle mapping reduced from 0.5433 to 0.1070 compared to existing techniques. Moreover, the water quality parameter inversion models for turbidity, color, total nitrogen, and total phosphorus achieved high determination coefficients (R² = 0.94, 0.93, 0.88, and 0.85, respectively). The spatial distribution maps of water quality parameters were consistent with in situ measurements. Overall, this UAV hyperspectral remote sensing method, enhanced by air–ground collaborative correction, offers a reliable approach for UAV hyperspectral water quality remote sensing and promotes the advancement of stereoscopic water environment monitoring. Full article

This study presents a comprehensive Quantitative Microbial Risk Assessment (QMRA) for Escherichia coli in northeastern Greece’s riverine and deltaic aquatic systems, evaluating potential human health risks from recreational water exposure. The analysis integrates seasonal microbiological monitoring data—E. coli, total coliforms, enterococci, Salmonella spp., Clostridium perfringens (spores and vegetative forms), and physicochemical parameters (e.g., pH, temperature, BOD₅)—across multiple sites. A beta-Poisson dose–response model within a Monte Carlo simulation framework (10,000 iterations) was applied to five exposure scenarios, simulating varying ingestion volumes for different population groups. Median annual infection risks ranged from negligible to high, with several locations (e.g., Mandra River, Konsynthos South, and Delta Evros) surpassing the World Health Organization (WHO)’s benchmark of 10⁻⁴ infections per person per year. A Gradient Boosting Regressor (GBR) model was developed to enhance predictive capacity, demonstrating superior accuracy metrics. Permutation Importance analysis identified enterococci, total coliforms, BOD₅, temperature, pH, and seasons as critical predictors of E. coli concentrations. Additionally, sensitivity analysis highlighted the dominant role of ingestion volume and E. coli levels across all scenarios and sites. These findings support the integration of ML-based tools and probabilistic modelling in water quality risk governance, enabling proactive public health strategies in vulnerable or high-use recreational zones. Full article

Capão da Roça, located in the municipality of Charqueadas, is one of the few areas of coal tailing deposits at the surface within the State of Rio Grande do Sul, Brazil that generates acid mine drainage (AMD). Over the course of 2007, the landfill was characterised in detail, and an active treatment plant involving pH neutralisation and metal precipitation operations was implemented to meet emission standards for mine water. In that year, based on the sulphur mass balance, it was estimated that the process of AMD generation would last for approximately two decades. The objective of this work was to study the temporal evolution of the parameters of the raw AMD. The effluent was analysed for 17 years on a monthly basis in regard to pH, acidity, metals (Fe, Al, and Mn), and sulphates. The results indicated an increase in pH (from 2.1 to 4.7), a decay in the concentration of metals (from 177.8 to 0.1 mg L⁻¹ for iron, 29.0 to 0.1 mg L⁻¹ for aluminium, and 3.1 to 0.6 mg L⁻¹ for manganese), sulphates (from 2023 to 307 mg L⁻¹), and acidity (from 539.5 mg CaCO₃ L⁻¹ to 3.96 mg CaCO₃ L⁻¹), which were adjusted to a first-order kinetic model in agreement with observations at some other mining sites. Over the years, the active lime neutralisation–precipitation treatment system has been efficient in treating the effluent. Today, most water quality parameters already meet emissions standards; however, the AMD treatment plant is still necessary to prevent pH fluctuations and to reduce the concentrations of manganese. For this reason, a transition from an active to a passive treatment system was considered. Pilot scale studies confirmed that channels filled with gravel-size limestone or slag enable the neutralisation/increase in the pH of the effluent and remove residual amounts of some metals, resulting in an effluent with no level of toxicity to the microcrustacean Daphnia magna. Full article

This study examines the effects of the extreme drought and heatwaves that occurred in Romania during the summer of 2024 on the microbiological and mycotoxicological quality of wheat (Triticum aestivum) stored until April 2025, as well as on the quality of wholemeal flour and bread derived from it. Comparative analyses were conducted against the contamination in wheat harvested in 2024. The hot and dry conditions significantly influenced the microbial and mycotoxicological contamination of both freshly harvested and stored wheat, as well as the derived flour and bread, due to their notably reduced moisture content and water activity. Although levels of total fungi, Fusarium-damaged kernels, and mycotoxins deoxynivalenol, aflatoxin B1, and ochratoxin A remained well below regulatory thresholds, higher contamination was observed in Transylvania and Moldavia Moldavia—particularly in the Curvature Carpathians, likely due to their cooler and wetter microclimates. The observed quality changes were strongly associated with alterations in physico-chemical, rheological, and colorimetric parameters, posing potential economic challenges for the milling and baking industries. The study recommends implementing integrated regional strategies to enhance wheat resilience, optimize production systems, and improve contamination control in response to increasing climate stress across Southeastern Europe. Full article

Waste stabilization ponds (WSPs) in humid, subtropical climates rely on stable temperatures and mechanical aeration to promote microbial activity. These critical infrastructures can lack operational resources to ensure efficient treatment, which can impact downstream communities. This study aims to use remote water quality sensor data to establish trends in a yearly dataset and correlate various water quality parameters for simplistic identification of pond health. A facultative WSP was monitored in two stages: the primary settling over a period of 14 months to evaluate partially treated water, and the secondary treatment pond for a period of 11 months to monitor final stage water quality parameters. A statistical analysis was performed on the measured parameters (dissolved oxygen, temperature, conductivity, pH, turbidity, nitrate, and ammonium) to establish a comprehensive yearly, seasonal, and monthly dataset to show fluctuations in water parameter correlations. Standard relationships in dissolved oxygen, conductivity, pH, and temperature were traced during the seasonal fluctuations, which provided insight into nitrogen processing by microbial communities. During this study, the summer period showed the most variability, specifically a deviation in the dissolved oxygen and temperature relationship from a yearly moderate negative correlation (−0.593) to a moderate positive correlation (0.459), indicating a direct relationship. The secondary treatment pond data showed more nitrogen species correlation, which can indicate final cycling during seasonal transitions. Understanding pond dynamics can lead to impactful, proactive operational decisions to address pond imbalance or chemical dosing for final treatment. By establishing parameter correlations, facilities with WSPs can strategically integrate sensor networks for real-time pond health and treatment efficiency monitoring during seasonal fluctuations. Full article

Eutrophication in rural ponds has become a widespread environmental concern, particularly in regions affected by agricultural irrigation. This study proposes an innovative Submerged Macrophytes–Daphnia magna combined remediation technology, aiming to synergistically improve water quality in naturally eutrophic ponds. Experimental water was sourced from rural ponds with preserved natural phytoplankton and bacterial communities. Treatments included low- and high-density D. magna, two submerged macrophyte species (Myriophyllum aquaticum and Ceratophyllum demersum), and their combinations. Results showed that combined treatments had no significant effect on pH but improved water transparency by up to 63.6% and significantly increased dissolved oxygen. Nutrient removal was notably enhanced in combined groups, with low-density D. magna + M. aquaticum achieving TN, TP, and NO₃⁻-N reductions of 56.1%, 63.2%, and 58.7%, respectively. Both macrophytes effectively mitigated NH₄⁺-N accumulation caused by D. magna, with M. aquaticum showing stronger inhibition. Furthermore, low-density D. magna reduced phytoplankton density, cyanobacteria density, chlorophyll-a, and microcystins by 74.8%, 80.3%, 68.9%, and 71.2%, respectively. This combined bioremediation approach demonstrates high ecological efficiency, scalability potential, and practical applicability for rural pond restoration. Full article

The use of saline water (low-quality water) in irrigation is a reality in many regions, especially in areas where fresh water is scarce, like semi-arid regions. However, it is important to adopt strategies to minimize the damage caused by salt stress to plants. The use of soil conditioners can help improve soil structure and water retention capacity, reducing salinity effects. The objective was to analyze the potential of a soil conditioner (hydrogel) as a mitigator of salty stress by irrigation with saline water in ornamental sunflower. Two sunflower cycles were carried out in a protected environment with a factorial 4 × 4 consisting of four doses of hydrogel polymer (0.0, 0.5, 1.0, and 1.5 g kg⁻¹) and four different levels of irrigation with saline water (0.5, 2.0, 3.5, and 5.0 dS m⁻¹). Plant biomass and physiological parameters, such as chlorophyll fluorescence measurements and gas exchange parameters, stomatal conductance, transpiration, and photosynthesis, were evaluated. Ornamental sunflower showed better performance with a saline water of 0.5 dS m⁻¹ without the use of hydrogel. At higher salinity levels, with a hydrogel dose of 1.5 g kg⁻¹, the sunflower achieved favorable performance, promoting gains in some gas exchange variables in plants irrigated with saline water at 3.5 dS m⁻¹ and in fluorescence-related variables within the range of 2.0 to 3.5 dS m⁻¹. This positive effect of hydrogel indicates its potential as a mitigating strategy against the adverse effects of salinity, contributing to the maintenance of plant vigor and physiological functionality in saline environments. Full article

The complex aquatic environment attenuates light transmission, thereby limiting the detection range of underwater laser systems. To address the challenges of limited operational distance and significant light energy attenuation, this study investigates optimized underwater lighting and imaging applications using a combined tricolor RGB (RED-GREEN-BLUE) white laser source. First, accounting for the attenuation characteristics of water, we propose a power-compensated white laser system based on transmission distance and underwater imaging theory. Second, underwater experiments are conducted utilizing both standard D65 white lasers and the proposed power-compensated white lasers, respectively. Finally, the theory is validated by assessing image quality metrics of the captured underwater imagery. The results demonstrate that a low-power (0.518 W) power-compensated white laser achieves a transmission distance of 5 m, meeting the requirements for a long-range, low-power imaging light source. Its capability for independent adjustment of the three-color power output fulfills the lighting demands for specific long-distance transmission scenarios. These findings confirm the advantages of power-compensated white lasers in long-range underwater detection and refine the characterization of white light for underwater illumination. Full article

Extensive practice has demonstrated that the continuous pursuit of high yields in the black soil region of Northeast China resulted in imbalances in soil nutrients and declines in both soil quality and water use efficiency. Alternate wetting and drying (AWD) irrigation offers a promising solution for increasing rice yield and maintaining soil fertility. However, the success of this irrigation method largely depends on its scheduling. This study examined the threshold effects of AWD on rice growth, yield, and soil nutrient availability in the Sanjiang Plain, a representative black soil region in Northeast China. A two-year trial was conducted from 2023 to 2024 at the Qixing National Agricultural Science and Technology Park. “Longjing 31”, a local cultivar, was selected as the experimental material. The lower limit of soil water content under AWD was set as the experimental factor, with three levels: −10 kPa (LA), −20 kPa (MA), and −30 kPa (SA). The local traditional irrigation practice, continuous flooding, served as the control treatment (CK). Indicators of rice growth and soil nutrient content were measured and analyzed at five growth stages: tillering, jointing, heading, milk ripening, and yellow ripening. The results showed that, compared to CK, AWD had minimal impact on rice plant height and tiller number, with no significant differences (p > 0.05). However, AWD affected leaf area index (LAI), shoot dry matter (SDM), yield, and soil nutrient availability. In 2023, control had little effect on rice plant height and tiller number among the different irrigation treatments. The LAI of LA was 11.1% and 22.5% higher than that of MA and SA, respectively, while SDM in LA was 10.5% and 17.2% higher than in MA and SA. Significant differences were found between LA and MA, as well as between LA and SA, whereas no significant differences were observed between MA and SA. The light treatment is beneficial to the growth and development of rice, while the harsh growth environment caused by the moderate and severe treatments is unfavorable to rice growth. The average contents of nitrate nitrogen (NO₃⁻-N), available phosphorus (AP), and available potassium (AK) in LA were 11.4%, 8.4%, and 9.3% higher than in MA, and 16.7%, 11.5%, and 15.0% higher than in SA, respectively. Significant differences were observed between LA and SA. This is because the light treatment facilitates the release of available nutrients in the soil, while the moderate and severe treatments hinder this process. Although panicle number per unit area and grain number per panicle in LA were 7.5% and 2.3% higher than in MA, and 10.8% and 2.2% higher than in SA, these differences were not statistically significant. Seed setting rate and thousand-grain weight showed little variation across irrigation treatments. The yield of LA was 10,233.3 kg hm⁻², 9.1% and 14.1% higher than that of MA and SA, respectively, with significant differences observed. Compared with the moderate and severe treatments, the light treatment increases indicators such as the number of panicles per unit area, grains per panicle, thousand-grain weight, and seed setting rate, resulting in significant differences among the treatments. Water use efficiency (WUE) decreased as the control level increased. The WUE of all AWD irrigation treatments was significantly higher than that of the control treatment (CK). Compared with CK, AWD reduces evaporation, percolation, and other water losses, leading to a significant decrease in water consumption. Meanwhile, the yield remains basically unchanged or even slightly increases, thus resulting in a higher WUE than CK. The trends in rice growth, soil nutrient indicators, and WUE in 2024 were generally consistent with those observed in 2023. In 2024, the yield of LA was 9832.7 kg hm⁻², 14.9% and 17.3% higher than that of MA and SA, respectively, with significant differences observed. Based on the results, the following conclusions are drawn: (1) AWD irrigation can affect the growth of rice, alter the status of available nutrients in the soil, and thereby cause changes in yield and WUE; (2) LA is the optimal treatment for increasing rice yield, improving the availability of soil available nutrients, and improving WUE; (3) Both MA and SA enhanced WUE; however, these practices negatively impacted rice growth and the concentration of soil available nutrients, leading to a concurrent decline in yield. To increase rice yield and maintain soil fertility, LA, with an irrigation upper limit of 30 mm and a soil water potential threshold of −10 kPa, is recommended for the Sanjiang Plain region. Full article

Yuanjiang Miscanthus lutarioriparius, which is rich in various bioactive components, exhibits significant potential in the development of functional foods. However, research on its application in dairy products remains relatively limited. This study fermented yogurt using different concentrations of Yuanjiang Miscanthus lutarioriparius water extract (0%, 0.1%, 0.2%, and 0.4%) as a functional additive, investigating its effects on the rheological properties, oxidative capacity, sensory quality, and volatile components of yogurt during storage. The results showed that during storage, the rheological properties (such as moisture content, apparent viscosity, storage modulus, etc.), the viable counts of Streptococcus thermophilus and Lactobacillus bulgaricus, and the DPPH/ABTS/FRAP radical scavenging rates of asparagus yogurt were significantly superior to those of the control group (p < 0.05), indicating that the lactic yogurt exhibited better texture, stability, and overall sensory acceptance. The 0.2% addition group exhibited the best inhibitory effect on lactic acid bacteria after acidification and the most stable acidity changes. The 0.4% addition group achieved an ABTS radical scavenging rate of 58.4% on the 7th day of storage, significantly higher than other groups (p < 0.05). The asparagus yogurt contained 64 volatile flavor compounds (20.31% alcohols and 21.88% ketones), which was higher than the control group (45 compounds), and introduced new aldehydes (tridecanal) and esters (methyl salicylate, ethyl palmitate), imparting a mild sourness and spicy flavor. Sensory evaluation results indicated that the 0.2% addition group scored the highest in texture, flavor, and taste, aligning with its rheological properties and color. This provides a theoretical basis for the development of highly stable and active functional asparagus yogurt. Full article

The increased presence of harmful algal blooms (HABs) is a concern for many aquatic environments, especially with the increasing effects of climate change. Members of the dinoflagellate genus Dinophysis have been shown to produce toxins that can cause Diarrheic Shellfish Poisoning (DSP) in humans who consume infected shellfish. The advancing oyster aquaculture industry in Delaware will require the development of management practices and monitoring HAB species to protect environmental and human health. Temperature, nutrients, and prey abundance can be drivers of Dinophysis blooms. D. acuminata has been historically identified at high concentrations (>200,000 cells L⁻¹) in water samples from Rehoboth Bay, DE, USA. However, the reach of spring blooms and how far they extend to aquaculture sites have not been determined. This study monitored an emergent HABs threat of a toxin-producing dinoflagellate, Dinophysis acuminata, by assessing a transect during the first recorded winter bloom in Torquay Canal and analyzing concentrations of chemical nutrients of combined nitrate and nitrite, and orthophosphate. Pearson correlation coefficient analysis between cell density (cells L⁻¹) and environmental variables across all sites was conducted to determine significant relationships between water temperature, Chl-a concentration, conductivity, dissolved oxygen (DO), combined nitrate and nitrite concentrations (NO_x), and orthophosphate concentrations (PO₄³⁻). Genetic techniques and PCR were utilized to determine the presence of Dinophysis using genus-specific primers to monitor cell density or abundance within the sediments during winter months. There were no significant correlations between environmental variables, and nutrient concentrations did not exceed EPA regulations. Molecular analyses of benthic sediments detected Dinophysis spp., offering insight into potential bloom origins. Overall, there is limited ecological data on Dinophysis acuminata in Rehoboth Bay, DE, USA. The results of this study will help strengthen resources for monitoring HAB species and understanding potential risks to oyster aquaculture in Delaware. Full article