Search Results (48,978)

The study of river basins is key to understanding the dynamics of microplastic (MPs) generation, transport, and accumulation in regions where various productive activities converge and waste management is limited. The objective of this study was to characterize economic activities in the Tecolutla River basin, Mexico, to identify risk factors associated with MPs generation and release throughout the production chain. A descriptive applied research study was conducted using a structured questionnaire administered to 19 economic units distributed across seven municipalities in the Tecolutla River basin, Veracruz, Mexico. The instrument allowed for the evaluation of the use of plastic materials in inputs, production processes, final products, and waste management practices. Among the economic units analyzed (n = 19), 94.7% reported the use of polymeric materials, with a predominance of thermoplastics such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polypropylene (PP), which have a high potential for secondary fragmentation. Within the tertiary sector, accommodation and food preparation services account for the highest proportion of units with limited separation and recycling practices. Activities in the secondary sector, especially the textile and construction industries, showed a high potential for releasing this pollutant due to the use of synthetic fibers, composite materials, and the absence of retention systems. The results provide a basis for the design of mitigation strategies targeting priority productive sectors at the watershed scale. Full article

With the growing trend toward insulator hybridization, higher requirements are imposed on the synergistic improvement of interfacial durability and pollution flashover performance. Machining annular grooves at the green-body stage and embedding silicone rubber enables the construction of an embedded structure with improved durability, forming hydrophilic/hydrophobic alternating surfaces. However, the outdoor insulation characteristics of such hybrid surfaces remain insufficiently investigated, and their engineering feasibility requires further validation. In this study, a series of hydrophilic/hydrophobic alternating surfaces were fabricated, and artificial pollution tests were conducted. The results show that the AC pollution flashover voltage exhibits a saturated increasing trend as the hydrophobic interfaces become more dispersed. When twenty 4 mm wide hydrophobic interfaces were distributed along a 16 cm creepage distance, the flashover voltage was 12.4% higher than that of a fully hydrophobic surface. These results indicate that appropriate design of hydrophobic interface distribution can achieve excellent pollution flashover performance even at relatively low hydrophobic coverage (≤50%). High-speed imaging combined with infrared thermography reveals the discharge mechanism governed by hydrophobic interface distribution from an electro–thermal coupling perspective. The coexistence of multiple dry bands induced by discrete hydrophobic interfaces is identified as the key factor enhancing flashover withstand capability. A static pollution flashover model was established to quantitatively estimate the AC flashover voltage, confirming the external insulation feasibility of the embedded hybrid concept. Full article

Large-scale reuse of copper tailings can mitigate environmental hazards and recover strategic elements; this work investigates the feasibility of producing foam glass-ceramics with high copper-tailing content (>70 wt%) by tuning the CaO/SiO₂ ratio to couple melt viscosity and crystallisation. The comprehensive utilisation of these tailings helps mitigate environmental pollution and enhance resource efficiency. In this study, foam glass-ceramics with varying CaO/SiO₂ ratios were synthesised through melt quenching followed by foaming heat treatment. The effects of different CaO/SiO₂ ratios on the foaming behaviour, crystallisation, and microstructure were investigated using DSC, FTIR, viscosity, XRD, SEM, and CT. The results indicate that increasing the CaO/SiO₂ ratio disrupts the three-dimensional network structure of the glass, which lowers the glass viscosity and influences the bubble size and distribution in the foam glass-ceramics. Additionally, the increased CaO content promotes crystal precipitation and enhances the compressive strength of the foam glass-ceramics. At a CaO/SiO₂ mass ratio of 0.22, the foam glass-ceramics exhibited the lower bulk density (240 kg/m³) and thermal conductivity (0.07 W/m·K). The materials also demonstrated good water absorption and compressive strength. This study highlights the potential of using copper tailings in foam glass-ceramics to improve their overall performance, offering promising energy-saving and environmentally friendly solutions. Full article

Nowadays, solar energy is becoming one of the most popular sources of renewable energy worldwide. Traditional fossil fuels cause pollution and climate change, while solar power offers a clean and sustainable alternative. However, effective planning requires accurate prediction of the amount of solar energy that can be produced. Prediction accuracy directly depends on two factors: the model’s hyperparameters and the feature set. In this study, we use boosting models, such as LightGBM, XGBoost, and CatBoost, to forecast solar power production. The prediction horizon is 60 min, which corresponds to short-term forecasting. Model tuning is performed using the NSGA-II multi-objective optimization algorithm. In this study, NSGA-II simultaneously tunes hyperparameters and a feature set of boosting models. We aim to enhance the performance of the NSGA-II algorithm in the early stages using the proposed method to generate the initial population. The initialization is based on an ensemble of filtering methods. The proposed approach promotes faster convergence in the early stages of the algorithm compared to the traditional initialization method. The results of numerical experiments are proven by the Wilcoxon test. Full article

This paper presents an analysis of the risk of failure of port structures in a modern seaport due to vessel impacts. The analysis addresses potential damage related to port maneuvers of self-maneuvering vessels and possible risk reduction options that can be applied to enhance port resilience. The proposed system model—including ship, port infrastructure, and environment—enabled the observation of both implemented and anticipated future risk reduction measures. The analysis was carried out using the ferry terminal in the large Polish Port of Gdynia as a case study. A Bayesian influence diagram—including decisions related to the implementation of risk reduction options—was used to determine the total risk associated with Ro-Pax ferry port calls. Sustainable risk management led to the implementation of a cloud-based monitoring system and, subsequently, to the design of a new terminal in line with the green port concept. The main result of the study was a quantitative assessment of the risk of damage to port infrastructure caused by ferries, related to ship maneuvering operations. A comparative assessment of the two locations demonstrated improved safety and reduced environmental pollution in the new Public Ferry Terminal. This improvement was made possible mainly by reduced spatial risk and the implementation of cold-ironing technology. Full article

The performance of biological wastewater treatment processes directly impacts water resource recycling and ecological safety. This year-long study compared full-scale wastewater treatment plants (WWTPs) using either the anaerobic/anoxic/aerobic (AAO) or modified Bardenpho process. By integrating water quality analysis with 16S rRNA sequencing, we examined how process type, influent quality, and seasonal factors affect microbial communities and treatment performance. Systems with high chemical oxygen demand (COD) and biochemical oxygen demand (BOD)/COD influent exhibited the best pollutant removal performance, with average nitrogen and phosphorus concentrations in the effluent as low as 7.0 mg/L and 0.1 mg/L, respectively. Optimizing a 1:9 influent distribution ratio between the pre-anoxic and first anoxic zones in the modified Bardenpho process increased total nitrogen (TN) removal efficiency by an average of 14 percentage points compared to the AAO process. Additionally, the modified Bardenpho process identified 1100 bacterial genera, indicating a more complex and stable community. Influent water quality had the most significant impact on microbial communities and treatment efficiency, followed by seasonal factors and process type. This study provides theoretical and data support for the optimization of wastewater treatment processes and seasonal regulations. Full article

Heavy metal contamination in drinking water remains a pervasive global challenge with significant consequences for environmental quality and human health. This review synthesizes findings from recent studies examining heavy metal concentrations in different sources of drinking water, including municipal tap water, groundwater, surface water, and bottled/sachet water across various geographical regions. The study used a systematic review of studies published from 2015 to 2024. The result showed a variation in the concentrations of heavy metals from all the sources, with tap water generally exhibiting lower heavy metal levels. Pb, Fe, Mn, and other metals persist in different sources and from many regions with levels above the permissible limits recommended by the World Health Organization (WHO) in some instances, which were sometimes linked to aging distribution systems and other pollution sources. Bottled and sachet water, commonly regarded as safer alternatives, also showed some levels of heavy metals such as Pb, Cd, and Cr, reflecting inconsistent packaging or production oversight. Surface waters display variability with heavy metals pollution, driven by industrial discharge, mining activities, agricultural runoff, and urban wastewater inputs. Groundwater sources, although naturally shielded, frequently contained elevated concentrations of As, Hg, and Ni due to both geological and anthropogenic factors. Pb concentrations were below detection limit in some of the published papers; however, the values reported in this study ranged from ND to 260.0 µg/L (tap water), ND to 0.259 mg/L (surface water), ND to 0.791 mg/L (groundwater), and ND to 123.15 µg/L (bottled water). Arsenic (As) concentrations ranged from ND to 692 µg/L from different sources, with the highest concentration from groundwater. Collectively, these patterns underscore the need for strengthened monitoring frameworks, improved water treatment technologies, and integrated pollution-prevention strategies. Addressing heavy metal contamination in drinking water requires coordinated policy approach and continuous monitoring to reduce human exposure and safeguard global public health. Full article

Severe wintertime particulate pollution (PM₁₀ and PM_2.5) affects the Santiago Metropolitan Region in Chile and is intensified by basin topography and frequent thermal inversions. Local authorities rely on the Critical Episodes Management (CEM) forecasting system, yet its predictive performance is variable. This study assesses CEM to identify operational vulnerabilities and propose data-driven improvements for urban air-quality governance. About ~1.2 million hourly meteorological and air-quality records (2017–2022) were analyzed using Generalized Additive Models (GAMs) to characterize key nonlinear relationships, and we evaluated the operational skill of the Cassmassi-1 PM₁₀ model and the WRF-Chem-based PM_2.5 forecasting component used by the system. Cassmassi-1 missed more than 50% of critical episodes and showed a false-alarm rate above 60%, consistent with limitations associated with static or incomplete emission representations. By contrast, the WRF-Chem-based component achieved episode prediction accuracy above 70%. GAM results indicate that wind speeds below 2 m s⁻¹, high diurnal temperature range, and relative humidity below 65% are strongly associated with extreme events. Considering the results, we recommend transitioning to nonlinear forecasting approaches that explicitly incorporate these meteorological thresholds and vertical stability indicators to improve alert reliability, strengthen urban resilience, and reduce population exposure. Full article

This study presents a comprehensive multi-objective optimization of sewage wastewater treatment using bio-based coagulants, guided by the Grey Wolf Optimizer (GWO) and its multi-objective variant (MOGWO). Experimental coagulation data, employing Citrullus lanatus and Cucumis melo as natural coagulants, were modeled using multivariate regression techniques, yielding high coefficients of determination (R² > 0.95) across key water quality parameters. The optimization process targeted maximal reductions in turbidity, total suspended solids (TSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) through strategic manipulation of pH and coagulant dosage. The single-objective GWO achieved significant outcomes, including a 96.68% turbidity reduction at pH 5 and 50 mg/L dosage. The MOGWO algorithm identified Pareto-optimal solutions, such as a 94.2% turbidity reduction at pH 5 and 72 mg/L dosage, and a balanced BOD reduction of 52.7% at pH 7. The predictive models indicated that optimal treatment conditions could reduce chemical usage by up to 90% compared to conventional coagulants, resulting in potential cost savings of up to 30%. Moreover, the algorithms demonstrated rapid convergence, averaging 200 iterations, highlighting their computational efficiency and robustness. These findings illustrate that integrating bio-based coagulants with advanced optimization techniques can achieve high treatment efficiency while reducing chemical inputs, thus directly supporting environmental sustainability by minimizing sludge and secondary pollution. In this situation, the wastewater treatment plant will focus on resource-recovery systems with less or no waste at the end of the treatment process. This approach aligns with circular economy principles by promoting eco-friendly, cost-effective wastewater treatment solutions suitable for resource-limited settings. The study offers a forward-looking pathway for environmentally responsible wastewater management practices that significantly reduce chemical dependency and contribute to pollution mitigation efforts. Full article

Noise pollution poses significant challenges to human health and quality of life; thus, high-performance damping materials are attracting increasing attention. Rubber has been extensively applied in these materials due to its viscoelasticity. However, the damping performance of these materials is often constrained by the intrinsically limited energy-dissipation capability of the polymer backbone, which lacks sound-absorbing functionalities. Herein, a cross-linked sliding graft copolymer (SGC) was incorporated into isobutylene-isoprene rubber (IIR) and chlorinated butyl rubber (ClIR) to fabricate high-strength damping elastomers. Unlike conventional covalently cross-linked polymers, the cross-linked SGC features mobile junctions, which can slide along the polyrotaxane backbone to redistribute and equalize chain tension, giving rise to the “pulley effect”. Benefiting from the intrinsically high energy-dissipation capability of SGC and the cooperative contribution of interfacial hydrogen bonding, the obtained SGC/IIR and SGC/ClIR blends exhibit both enhanced damping performance and mechanical properties. The synergistic improvement in damping capacity and mechanical robustness renders the SGC/rubber blends as promising candidates for advanced sound-absorption applications. Full article

Microplastic (MP) contamination in freshwater systems has emerged as a growing environmental concern. This study investigated the occurrence and seasonal variability of MPs in surface water, the water column, and sediments at selected sites in Lake Alhajuela, Panama. Lake Alhajuela is an artificial reservoir that supplies water to the Panama Canal lock system and to the cities of Panama and Colón, serving more than 50% of the country’s population. MPs were isolated using two digestion protocols followed by density separation, and fragments and films larger than 1 mm were chemically characterized using FTIR–ATR spectroscopy. Mean MP concentrations were 759 ± 536 MPs L⁻¹ in surface water, 328 ± 140 MPs L⁻¹ in the water column, and 109 ± 87 MPs g⁻¹ in sediments. Statistical analyses revealed no significant differences among sampling sites; however, significant seasonal differences were observed (p < 0.01). Smaller MPs (63–249 µm) were more abundant compared to larger MPs (>250 µm). Fragments and fibers were the most predominant type of MP reported. Our results confirm the presence of MPs in the surface and water column, as well as sediments of the Alhajuela Lake. Further studies are needed to elucidate the fate, sources, transport, and distribution of MPs across Lago Alhajuela as well as to assess the lake’s potential contribution of MPs to Gatun Lake and the Panama Canal system. Full article

To investigate the characteristics and health risks of heavy metal (HM) contamination in soils of typical industrial sites during urban renewal, this study selected Pudong New District, Shanghai, as a case. Seven HMs (Cd, Pb, Cu, Zn, Ni, Hg, and As) were analyzed for their concentrations, ecological risks, spatial patterns, and potential sources. Inverse Distance Weighted (IDW) interpolation was used to assess spatial distribution, Random Forest (RF) regression to predict HM concentrations, and a two-dimensional Monte Carlo simulation to evaluate human health risks. The results showed that all HMs except As exceeded Shanghai background values in surface soils, with varying levels observed in subsoil and saturated layers. The Index of Geoaccumulation (Igeo) and Risk Index (RI) indicated low contamination and moderate ecological risk. Pearson correlation combined with Positive Matrix Factorization (PMF) identified four major sources: traffic emissions dominated by Cd and Zn, combustion-related sources dominated by Pb and Hg, industry-related inputs dominated by Cu and Ni, and a natural source dominated by As. The RF model demonstrated strong predictive accuracy for Cd, Pb, Hg, and As (R² = 0.80–0.94), and predicted values were consistent with observations. Monte Carlo results showed that non-carcinogenic risks for children and adults were within acceptable limits, while carcinogenic risks reached “notable” levels with probabilities of 62.06%, 55.65%, and 22.49% for children, adult females, and adult males, respectively. Cd and As were identified as key contributors. This work provides scientific support for soil pollution prevention and remediation during urban renewal. Full article

Cowpeas are a legume widely consumed in Brazil. Given this, the objective of this study was to investigate the presence of metals (loids) in pods and leaves of Vigna unguiculata located near a highway with high vehicle traffic and a landfill, and to assess possible risks to human health. Pod and leaf samples were collected at nine points between the highway and the landfill. The elements were analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and quantified. The risk to human health was assessed using risk quotient and risk index values. A quantitative analysis of the chemical elements was also performed using the maximum tolerable intake level. Element concentrations were higher in the leaves than in the pods. The human health risk analysis showed that the average daily consumption of both pods (44 g/day) and leaves (67 g/day) may pose a chronic health risk to adult men and women, due to simultaneous exposure to multiple metals. It was concluded that the plant is contaminated and that its ingestion can cause toxicity, warranting warnings against cultivating areas near anthropogenic activities that may be contaminated with heavy metals, thereby affecting nutritional safety. Full article

Dust pollution induced by blasting during tunnel construction via the drill-and-blast method poses a severe threat to workers’ health and construction safety. To address this issue, a wet chord grid dust removal and purification device adaptable to deep-buried long tunnels was developed in this study. The device integrates dust control and removal functions, featuring mobility, high purification efficiency, and water recycling capability. Through experimental tests, the optimal operating parameters of the system were determined: the dust removal efficiency reached a peak of 94.3% (laboratory optimal value from the basic parameter optimization test) when the frequency of the extraction axial flow fan was set to 30 Hz and the cross-sectional wind speed of the chord grid reached 3.34 m/s. The circulating water tank achieved the optimal water treatment performance under the conditions of a relative buried depth of 0.42 for the water inlet, a volume ratio of 1:2 for the sedimentation area to the clear water area, and a relative baffle height of 0.65. Numerical simulations based on CFD software (2021) revealed that the on-site dust removal efficiency of the device reached 79.86% and 87.9% under the working conditions where the tunnel face was 10 m and 100 m away from the connecting passage, respectively, which are in good agreement with the field measurement results. In the practical application at the Shierpo Tunnel of the Guangxi Tianba Expressway, the device achieved an average total dust removal efficiency of 78.4%, with 81.2% removal efficiency for PM₁₀ and 76.5% for PM_2.5, demonstrating excellent engineering applicability and dust removal performance for respirable dust. This study provides effective technical support and a theoretical basis for improving the construction environment of drill-and-blast tunnels. Full article

Against the backdrop of the dual-carbon strategy promoting the green and low-carbon transformation of the shipping industry, pollutant emissions generated during vessel berthing operations have become a critical challenge in port environmental governance. To address the combined effects of the priority berthing policy for new energy vessels and time-of-use electricity pricing, a joint optimization model for berth and shore power allocation is developed with the objectives of minimizing the total economic cost of vessels and the environmental tax cost associated with pollutant emissions. An improved Adaptive Large Neighborhood Search algorithm (ALNS-II) is further designed to solve the model. Numerical experiments based on actual port data verify the effectiveness of the proposed model and the superiority of the algorithm. The results indicate that, under time-of-use electricity pricing, the priority berthing policy for new energy vessels can shorten their waiting time at anchorage and encourage fuel-powered vessels to shift toward electrification. When the peak-to-valley electricity price ratio increases from 4.1:1 to 7.5:1, the environmental tax cost of pollutant emissions decreases slightly, whereas the total economic cost of vessels rises by 4.17%, suggesting that the peak-to-valley electricity price ratio should not be set excessively high. In addition, increasing the proportion of new energy vessels to 70% is more conducive to improving the overall economic and environmental performance of ports. The findings provide a theoretical basis and decision support for the optimal allocation of port resources under the coordination of multiple policies. Full article