Atmospheric and Oceanic Sciences

The occurrence and accumulation of novel perfluoroalkyl and polyfluoroalkyl substances (PFAS) have emerged as a scientific concern in recent years. While numerous studies have identified elevated concentrations of certain emerging PFAS, the sources and environmental accumulation differences of many homologues remain insufficiently characterized. In this study, we employed suspect and nontarget screening to characterize both legacy and emerging PFAS across environmental matrices, including water, sediment, and soil, surrounding an industrial park with predominant perfluoroalkyl carboxylic acids (PFCAs) contamination. A total of 32 classes comprising 112 compounds were identified, including 80 emerging PFAS detected through the screening approach. In addition to PFCAs, emerging PFAS, including perfluoroalkyl ether carboxylic acids (PFECAs), perfluoroalkyl alcohols (PFAs), and PFA derivatives, were frequently detected in the study area, primarily in water and sediment samples. In contrast, the contamination profile was less complicated in soil samples, where PFCAs were the predominant homologues. The median total concentrations of target PFAS in water, sediment, and soil samples were 427 ng/L, 4.17 ng/g of dw, and 3.92 ng/g of dw, respectively. Predicted risk assessment further indicated that these emerging PFAS with high concentrations pose non-negligible risks to both ecological and human health, underscoring the need for further investigation into their potential impacts.

This study explored the hydraulic characteristics and the adaptability to water-level fluctuations of the vertical-slot fishway. The maximum allowable water depth difference between the entrance and exit was calculated for a one-entrance fishway and two-entrance fishways with different entrance distances (100 m, 200 m, 300 m) under insufficient entrance water depth, with a fishway slope of 2% and an exit water depth of 2.5 m. It was found that the maximum allowable water depth difference between the 1# entrance and exit of the two-entrance fishways (0.71 m, 0.85 m, 0.93 m) was greatly larger than that of the one-entrance fishway (0.48 m). Additionally, the maximum allowable water depth difference in the two-entrance fishway increased with the increased distance between the two entrances. The relationship between the maximum allowable water depth difference and the distance of the two entrances followed a logarithmic function. We suggested that the 2# entrance should be at least 1.6 m when the water depth of 1# entrance was decreased to 1.8 m. When the water depth of the 1# entrance was gradually decreased to 1.6 m, the water depth of the 2# entrance also gradually decreased to 1.2 m. The distance between the 1# entrance and 2# entrance subsequently changed. It was noteworthy that the conclusions proposed in this study were strictly limited to vertical-slot fishways with a slope of 2%, exit water depth of 2.5 m, similar geometric parameters, and target cyprinid species. Furthermore, different slopes or exit water depths should be studied to extend the relationship by introducing correction coefficients from subsequent studies. This study can provide references for the design and optimization of future fishway projects.

The interaction of emergent vegetation and three-dimensional (3D) bedforms is essential for understanding turbulent flow dynamics in curved channels. A laboratory investigation can help to collect required data under controlled conditions. Experiments were conducted in a 9.5 m-long, 0.9 m-wide recirculating flume incorporating a 90° bend and a sculpted 3D pool bedform. Artificial rigid vegetation, designed to replicate the hydraulic behavior of natural emergent plants, was installed along both sidewalls. Instantaneous three-dimensional velocities were recorded using an acoustic Doppler velocimeter (ADV) across multiple cross-sections under both bare-bed and vegetated conditions. The results reveal that emergent vegetation markedly increases flow resistance, distorts mean velocity distributions, and suppresses the classical logarithmic velocity profile, particularly within the bend and pool regions. The combined presence of vegetation and the 3D pool bedform amplified turbulence intensity, elevated Reynolds shear stresses, and redistributed turbulent kinetic energy (TKE), which increased by up to sevenfold from the bend entrance to its exit. In vegetated pool sections, Reynolds stresses were approximately 12% greater than under bare-bed conditions, underscoring the synergistic effects of vegetation drag, secondary circulation, and flow separation in producing anisotropic turbulence. These findings highlight the importance of incorporating vegetation–bedform interactions in fluvial modeling frameworks, with significant implications for sediment transport prediction, channel stability evaluation, river restoration, and aquatic habitat design.

Tidal inundation plays a critical role in maintaining the ecosystem services of the Sundarbans mangrove forest. In this study, we configured and calibrated a coupled one-dimensional (1D) river network and two-dimensional (2D) floodplain hydrodynamic model for the Sundarbans in Bangladesh. Model calibration was performed using gauged water levels, inundation maps, and Google Earth (Version 7.3.6) imagery. Using the calibrated model, we assessed potential changes in inundation extent, depth, and duration across the Sundarbans for varying freshwater inflow and tidal height scenarios. Results show variation in inundation extent, depth, and duration spatially and temporarily across the Sundarbans. Inundation is relatively less during February-March (end of the dry season) and high in July-August (mid-wet season). Approximately 3158 km2 (85.1%) of the Sundarbans experiences at least one inundation in March, increasing to about 3658 km2 (98.6%) in July. Although a large proportion of the Sundarbans inundate during daily tidal cycles, the mean inundation depth remains shallow (0.24 to 0.33 m) due to flat topography. The influence of freshwater inflow on inundations is small (<2%). In contrast, the impacts of tidal magnitude are substantial on both inundation extent and depth. These findings provide valuable insights on inundation dynamics for understanding the hydrological and ecological functioning of the Sundarbans.

Ultrapure water (UPW) distribution loops must deliver stable hydraulics while limiting contamination from polymer piping. This study integrates computational fluid dynamics (CFD) with systematic pipe autopsy to examine contaminant behavior in a pilot-scale UPW loop constructed using chlorinated polyvinyl chloride (CPVC) and polyvinylidene fluoride (PVDF) and operated under identical conditions. CFD predicted nearly identical loop-scale velocity, pressure, and temperature fields for both materials, and identified low-shear recirculation at elbows and downstream tees as zones of elevated particle residence. Lagrangian particle tracking (0.05 μm, no-sticking) showed rapid breakthrough and complete flushing within 13 min, providing a hydraulic susceptibility map for transient retention. After eight months of operation, 17 sections were inspected endoscopically and leached at 60 °C. CPVC exhibited yellow–brown discoloration and highly heterogeneous total organic carbon (TOC) release with hot spots of 16–18 mg·L−1, whereas PVDF showed low, spatially uniform TOC (0.4–2.3 mg·L−1) and minimal fouling; inorganic ions remained at sub-mg·L−1 levels for both materials. Overall, geometry governs where contamination can accumulate, while material properties control its magnitude and persistence, with PVDF providing greater resistance to long-term organic contamination than CPVC.

The optimal design of riverbank retaining walls requires a careful balance between structural safety, constructability, and economic efficiency. In this study, a constraint-aware optimization framework is developed for the design of concrete gravity retaining walls by explicitly incorporating stability, serviceability, and geometric feasibility constraints. Several metaheuristic algorithms are comparatively evaluated under identical computational conditions using 30 independent runs, a population size of 50, and 1000 iterations. The results demonstrate that enforcing geometric constraints is essential to prevent non-physical designs and to ensure engineering realism. Quantitative analysis shows that the Flower Fertilization Optimization (FFO) algorithm yields the minimum wall weight, reducing material usage by approximately 19% compared to more conservative solutions. In contrast, the adaptive exploration artificial bee colony (AEABC) algorithm exhibits the most robust and repeatable convergence behavior with low statistical dispersion across independent runs. An economic assessment based on concrete volume further confirms the direct impact of material efficiency on construction cost. The proposed framework highlights the importance of constraint-aware optimization for achieving reliable and economically efficient retaining wall designs.

Axial flow pumps, widely utilized in critical fields such as agricultural irrigation, urban water diversion and flood control, play an indispensable role in large-scale water transport and drainage projects due to their high-flow and low-head characteristics. This study systematically investigates the influence of tip clearance on the external characteristics and internal flow field of a large-scale axial flow pump (model 1800GZX-125). By combining numerical simulations with experimental validation, a comparative analysis was conducted under four tip clearance sizes (3 mm, 12 mm, 17.5 mm, 24 mm) and various flow conditions. The results indicate that increasing the tip clearance generally reduces the pump head and peak efficiency. It also alters the blade pressure distribution, expands the low-pressure region, and intensifies tip leakage flow. While vorticity overall increases, it weakens locally under certain conditions due to changes in leakage flow patterns. Entropy generation analysis further reveals that larger clearances lead to significantly increased energy losses, thereby degrading external performance. These findings provide a theoretical basis for improving the performance and operational stability of axial flow pumps.

Wastewater from food processing industries contains synthetic dyes and preservatives that may pose phytotoxic and genotoxic risks. The present work represents an exploratory study based on a wastewater source and sampling period. Wastewater was characterized by physicochemical analysis and high-performance liquid chromatography (HPLC). Onion seeds and bulbs were exposed to 0% (control), 20%, 40%, 60%, 80%, and 100% wastewater dilution. DNA was extracted from root cells using the cetyltrimethylammonium bromide (CTAB) method. The DNA damage was analyzed by the comet assay. HPLC analysis confirmed the presence of sorbic acid, citric acid, benzoic acid, butylated hydroxyanisole (BHA), and butylated Hydroxytoluene (BHT) by showing corresponding peaks. The mean root length in wastewater was significantly reduced by 55%, 50%, and 65% on days 3, 5, and 7, respectively, relative to the control. On day 3, the highest genotoxicity at 100% wastewater was indicated by 96.69% tail DNA, a tail moment of 108.3 a.u., an Olive tail moment of 58.01 a.u., and a comet length of 136 µm. Enhanced DNA damage persisted on days 5 and 7, with comet lengths reaching 127–149 µm and 111–182 µm, respectively. Although the observed effects may reflect general cytotoxicity arising from a complex wastewater mixture and showed that untreated food processing wastewater presents a significant genotoxic risk and requires effective treatment prior to reuse.

The rapid development of rural and peri-urban areas increases the demand for decentralized wastewater treatment systems. Small wastewater treatment plants (SWTPs) with a capacity below 2000 PE are becoming an important element of local water protection and circular-economy strategies, yet clear guidelines for selecting appropriate technologies are still lacking. This study analyzes the criteria used in decision-making for SWTPs from a multi-stakeholder perspective and evaluates the relative importance of technical, economic, environmental and social factors. The research was conducted in Poland and included a survey of 130 respondents representing six stakeholder groups (officials, operators, designers, contractors, scientists and residents). Respondents allocated weights to four main groups of criteria and assessed eleven detailed parameters on a 1–10 scale. The data were analyzed using descriptive statistics, the Kolmogorov–Smirnov test with the Lilliefors correction to verify distribution assumptions, and the Kruskal–Wallis test to examine differences between stakeholder groups. The results show a consistent hierarchy of criteria, with technical reliability, treatment efficiency and operating costs ranked as the most important factors. Social and environmental aspects were assessed as relevant but secondary. Only minor differences between stakeholder groups were observed. The study highlights the need for integrated, multicriteria approaches in SWTP planning, particularly in dispersed rural areas. The findings may support local authorities, designers and investors in technology selection. The research is limited by the non-probability sampling strategy, the national scope of the dataset and the cross-sectional character of the survey.

Understanding and predicting climate change impacts on the terrestrial water cycle is essential for water resources management and hazard prevention. This study aims to project future runoff of a densely-populated river basin, the Pearl River Basin (PRB), under different Shared Socioeconomic Pahway (SSP) scenarios, by combining the Soil and Water Assessment Tool (SWAT) model and the CMIP6 climate projections. Results show that climate change will significantly increase the runoff of the PRB, with changing rates of 0.21, 0.20, 0.11, and 0.17 mm/month/year for low- to high-emission scenarios SSP126, SSP245, SSP370, and SSP585, respectively. Future runoff exhibits strong seasonal and spatial variability due to complex changes in precipitation and potential evapotranspiration across the basin. The PRB may experience higher flood risks during the wet season under all SSP scenarios, driven by a ~15% increase in runoff during the wettest month during 2061–2100 relative to that of 2021–2060. Conversely, drought risks may escalate in the East River Sub-basin of the PRB during the dry season under the high-emission scenarios (SSP370 and SSP585), with a ~20% reduction in runoff during the driest month during 2061–2100 relative to that of 2021–2060. The highest-emission scenario (SSP585) may lead to the most drastic hydrological changes, including increased risks of flooding and drought across different parts of the PRB. Our findings suggest intensified water cycling and increased hydrological risks in the PRB under a changing climate, highlighting the necessity of future water resource management to consider potential climate change impacts to mitigate the risks of floods and droughts effectively.

Ningbo (NGB), a major port city on China’s east coast, is defined by a network of over 100 rivers across three major catchments. From the 1970s to the 2000s, extensive engineering, including channelisation and embankment construction, was used to manage flood risk during rapid urbanisation. Since the 2010s, however, the city has shifted towards smart flood management. The Ningbo government and Water Bureau have deployed digital twins and technologies like 3D flood mapping and real-time monitoring, significantly improving precision. Our study demonstrated that this smart technology performed effectively during recent extreme events, namely typhoons In-Fa (2021) and Muifa (2022), helping the Municipal Bureau to safeguard public safety. This success strengthens municipal and national commitments to climate resilience. Nevertheless, further advancement of the digital twin platform is required. Key priorities include boosting computational capacity, improving cross-departmental coordination, establishing open data sharing, and integrating artificial intelligence (AI) to enhance decision-making during future climate extremes.

Human activities in Panama, such as agriculture, industry, and transport, have led to the release of pollutants that affect the health of marine and coastal ecosystems. However, there is a lack of bibliographic compilation studies to understand the current state of research on marine pollution in Panama. In recent years, bibliometric studies have attracted attention due to the development of new analytical and integrative online tools. This study conducts a bibliometric analysis of marine pollution and its environmental effects on Panama’s coastal areas. The results show consistent growth in scientific production, with increased collaboration among researchers. However, the involvement of national institutions is limited, highlighting the need to strengthen local research. Most publications focus on environmental sciences, with a recent shift towards studying a broader range of pollutants.

Water resources and environmental systems face unprecedented pressure from the combined effects of climate change, rapid urbanization, population growth, land-use transformation, and intensifying economic activities [...]

This study presents an experimental evaluation of different optical fibers for soft-tissue laser ablation using an Echolaser system, developed by Elesta S.p.A., for minimally invasive therapies. Eight fibers with varying core diameters, numerical apertures, and tip geometries (flat, conical radial, and spherical) were compared to investigate the influence of optical properties on the ablation dimensions and thermal profiles. The experiments were conducted at 1064 nm with powers of 3, 5, and 7 W and delivered energies ranging from 1200 to 3600 J. The results highlight how the fiber characteristics affect tissue ablation, identifying the configurations suitable for minimally invasive prostate applications. These findings provide an experimental reference for the development of laser-based biomedical approaches.

Optical defect detection based on bright-field imaging is currently one of the most widely applied inspection techniques in wafer fabrication. However, particle defects on the surface of patterned wafers are often small in size. Under bright-field optical imaging conditions, defect signals are easily overwhelmed by complex background textures and noise, seriously affecting the detectability and positioning accuracy of defects. To address this issue, this paper proposes BWD-DETR, a detection framework tailored for wafer surface defects under bright-field imaging. Based on the RT-DETR baseline, this framework integrates a wavelet backbone, an SMFI module, and a CAS-Fusion module, achieving an AP50 of 96.56% and an AP50:95 of 54.94% in bright-field wafer defect detection, with improvements of 1.64% and 2.17% over the baseline, respectively. The proposed method can effectively enhance the detection capability for sub-micron defects on the wafer surface.