Water, Air, & Soil Pollution最新文献

Urban rivers are hotspots for atmospheric CH₄ and CO₂ emissions. Monitoring their fluxes is of great significance for understanding the carbon cycle process disrupted by human activities and assessing the carbon budget of river basins. The emissions of greenhouse gases from natural rivers have been widely studied, but the impact of urbanization and land use changes caused by human activities on the distribution pattern of carbon fluxes in rivers around cities is still not fully understood. To bridge this knowledge gap, this study set up 14 sampling points with a total of 28 samples. By using the static flux chamber method, the fluxes of CH₄ and CO₂ in the Fen River, a tributary of the Yellow River, were determined, and the relevant physical and chemical indicators of the water body were monitored simultaneously. The results showed that both gases were in a supersaturated state, and the average values of FCH₄ and FCO₂ reached 1005.53 ± 459.16 μmol·m⁻²·d⁻¹ and 289.75 ± 176.45 mmol·m⁻²·d⁻¹, respectively. The FCH₄ of Wet month was 1.4 times that of Dry month, and the FCO₂ of Wet month was 2.4 times that of Dry month. The ratio of built-up area respectively explained 54% and 31% of the spatial variations of FCH₄ and FCO₂. The structural equation model indicates that the standardized direct effects of urbanization on FCH₄ and FCO₂ were 0.21 and 0.23 respectively, while the standardized indirect effects through physical and chemical indicators of water bodies (TP, DOC, NH₄⁺ and EC) were 0.47 and 0.40 respectively. Thus, nutrient inputs became the primary drivers for the increase in FCH₄ and FCO₂. This study suggests that FCH₄ and FCO₂ in river sections near urban areas are more sensitive to land-use changes and water pollution. Land use and urbanization indirectly affect riverine FCH₄ and FCO₂ by altering nutrient inputs. These findings underscore that FCH₄ and FCO₂ in river segments near urban areas are more sensitive to changes in land use and water pollution. Land use and urbanization indirectly influence riverine FCH₄ and FCO₂ by altering nutrient inputs. Such understanding is critical for future coordinated efforts aimed at pollution reduction and carbon mitigation along urban–rural river gradients, as well as for addressing the pressures of climate change.

Graphical Abstract

Water pollution is a major global challenge, particularly in urban areas where inadequate management of municipal solid waste (MSW) poses substantial risks to the quality of both surface and groundwater resources. This study investigates the seasonal dynamics of groundwater and surface water contamination near the open dumpsite at Burma Camp in Dimapur, Nagaland. An integrated approach using the Entropy Weighted Water Quality Index (EWQI), Principal Component Analysis (PCA), and correlation analysis was employed to assess various physicochemical and heavy metal parameters, namely pH, electrical conductivity (EC), turbidity, hardness, total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), iron (Fe), cadmium (Cd), copper (Cu), lead (Pb), manganese (Mn), zinc (Zn), and cobalt (Co), in pre-monsoon, monsoon, and post-monsoon seasons. Multivariate statistical methods, like PCA and correlation techniques, were adopted to examine the correlations among water quality variables and determine possible causes of water contamination. In EWQI, parameter weights were objectively derived from information entropy, ensuring variables with greater variability exerted a stronger influence on final index values. The EWQI revealed that groundwater sites (G-1 to G-5) near the dumpsite consistently exhibited ‘extremely poor’ quality (EWQI > 200) across all seasons, with values ranging from 1314 to 2200. In contrast, river sites (R-2 and R-5) showed significant degradation, with values categorized as ‘poor’ (150–200) during the pre-monsoon (189 to 137) and post-monsoon (140 to 109) periods, while reaching ‘extremely poor’ levels (EWQI > 200) during the monsoon (208 to 122) due to increased leachate runoff. The PCA and the correlation matrix analysis revealed that leachate infiltration from the dumpsite is the primary source of contamination, with additional influences from both anthropogenic activities and geogenic sources. These findings will help in providing valuable insights and recommendations for improving MSW management and disposal in Dimapur, emphasizing the need for improved leachate management, water quality monitoring, and sustainable waste disposal strategies to mitigate long-term environmental and public health risks.

This study used samples collected from five major rivers in South Korea to investigate the presence and potential transmission pathways of plant viruses through river water. While virome analyses have been conducted in various water systems, research on the distribution and prevalence of plant viruses in freshwater environments remains limited. However, understanding the viral communities in these systems is critical for assessing potential risks to agriculture and environmental health. This study analyzed water samples from the Yeongsan River (YE), Geum River (GE), Seomjin River (SE), Han River (HA), and Nakdong River (NA) using metatranscriptomics. Several plant viruses, including cucumber green mottle mosaic virus (CGMMV), tobacco mild green mosaic virus (TMGMV), pepper mild mottle virus (PMMoV), youcai mosaic virus (YoMV), and soybean yellow common mosaic virus (SYCMV) were identified, with PMMoV being consistently detected across all rivers. Absolute quantification using nanoplate-based digital PCR (dPCR) confirmed the presence of these viruses, and plant pathogenicity tests were verified using indicator plants. Importantly, no novel plant viruses were discovered in this study. Instead, our findings highlight that freshwater systems serve as reservoirs and transmission pathways for already well-documented plant viruses. This emphasizes the need to shift focus toward quantitative risk assessment and regional surveillance of these waterborne plant viruses to safeguard agricultural sustainability.

Cities are the basic administrative units for formulating and implementing policies to reduce pollution and carbon dioxide. This study used statistical analysis and Kriging interpolation to clarify the spatiotemporal fluctuation characteristics of PM_2.5 and O₃ at different time scales in Chongqing from 2017 to 2022. It also explored the compliance rate of pollutants and their correlation. In addition, GeoDa software was used to examine the spatial autocorrelation and clustering of pollutants. Finally, relevant measures and suggestions were put forward from different perspectives of provinces, cities, districts and counties. The results showed that PM_2.5 and O₃ pollutions were still particularly serious and there was a complex linear interaction between them. Furthermore, PM_2.5 and O₃ both have significant positive spatial autocorrelation and aggregation characteristics, and their high-high agglomeration areas are mainly concentrated in the city proper of Chongqing. These results can provide potential guidance for developing differentiated and refined air pollution prevention and control measures in the region, thereby promoting the continuous improvement of regional air quality. More importantly, it can provide a reference for the practice of collaborative carbon pollution reduction and regional collaborative emission reduction in China’s megacities. It also provide insights and methods that can be applied to other countries (WHO: World Health Organization; SCB: Sichuan Basin; NAAQS: National Ambient Air Quality Standards of China; MEIC: Multi-resolution Emission Inventory for China; VOCs: Volatile Organic Compounds).

This study investigates the dissipation kinetics, biodegradation, and health risk assessment of formetanate hydrochloride (FMT) in pepper under field conditions. Utilizing LC–MS/MS, the degradation behavior of FMT was analyzed, revealing significant residue reduction when bacterial strains were applied. The bacteria mix treatment exhibited the most effective residue dissipation, reducing health risks by minimizing both chronic and acute exposure. Climatic factors such as humidity and temperature significantly influenced the dissipation rates, emphasizing the need for localized residue management strategies. The study underscores the potential of microbial treatments as eco-friendly solutions for managing pesticide residues, promoting food safety, and ensuring sustainable agricultural practices. Further research should explore FMT dynamics in diverse crops and environmental conditions to optimize pesticide management frameworks.

In this study, nickel aluminum layered double hydroxide (Ni/Al LDH) is synthesized and then modified with starch to form S-Ni/Al LDH based on a simple co-precipitation method. The adsorption potential of S-Ni/Al LDH is evaluated for the adsorption of anionic azo and cationic dyes, with key variables controlled (e.g., temperature, adsorbent quantity, pH, and contact duration). The adsorption process is determined to be exothermic and spontaneous while being governed dominantly by monolayer chemisorption processes in line with a Langmuir isotherm and pseudo-second-order kinetic model. The maximum adsorption capacity values for S-Ni/Al LDH composite, when assessed in terms of Langmuir isotherm, are 329, 160, and 68.4 mg/g against Congo Red, Sunset Yellow, and Orange G, respectively (with the corresponding partition coefficients of 378, 146, and 7.42 mg g⁻¹ μM⁻¹). Further, S-Ni/Al LDH is readily regenerated up to four cycles with slight reduction in adsorption capacity using an aqueous Na₂CO₃ solution. As such, the practical utility of the starch-modified LDH for wastewater treatment applications is demonstrated for applications toward wastewater treatment.

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Microplastic (MP) contamination has recently become a growing environmental concern; however, scientific understanding of its occurrence in freshwater systems of Bagmati River remains limited. Recognizing this gap in knowledge, the present study was conducted to assess the abundance, distribution, and characteristics of MP in the Bagmati River and key water quality parameters, including pH, electrical conductivity, total dissolved solids, and turbidity. Fifteen sampling sites were selected across upstream, midstream, and downstream zones based on human activity levels. Water samples were digested using hydrogen peroxide and ferrous sulfate, followed by density separation. MP were identified under a stereomicroscope, and polymer types were confirmed using Fourier Transform Infrared (FTIR) spectroscopy. MP concentrations ranged from approximately 2.0 to 129 MP/L, with an average of 29 MP/L. Blue-colored MP (66%) were most dominant, followed by red (22%), while fibers (94%) overwhelmingly prevailed over fragments (6%). Polyethylene (PE) (70%) and polypropylene (PP) (30%) were the major polymer types identified. Statistical analysis using the Kruskal–Wallis test with post-hoc pairwise comparisons revealed significantly higher MP abundance in the midstream than the upstream segment (p = 0.044), with an increasing trend downstream. The predominance of fibers and the spatial pattern show that urban runoff, untreated wastewater, and mismanaged solid waste are major MP sources. The presence of MP across all sites shows widespread urban-origin contamination and potential ecological and human health risks. Strengthening wastewater treatment, waste segregation, and public awareness is crucial to mitigate MP pollution and safeguard the ecological integrity and socio-cultural values of the Bagmati River system.

Denitrification in suspended sediments (SPS) plays a critical role in nitrogen removal within aquatic systems, yet the influence of pollution gradients on this process remains poorly understood. This study investigated denitrification performance and microbial metabolic adaptations across SPS from pollution-defined riparian zones (20 m near-shore/L20, 40 m mid-shore/L40, 100 m far-shore/L100) in Meiliang Bay of eutrophic Lake Taihu. Results showed a clear contamination gradient: nutrients and heavy metals decreased successively from near-shore (highest) to mid-shore to far-shore (lowest). Notably, SPS in L40 had the higher N₂ and N₂O release rates than L20 and L100, despite intermediate pollution levels, suggesting non-linear relationships between contamination magnitude and denitrification efficiency. Compared with L20 and L100, L40 sediments exhibited superior carbon metabolism (EMP/PPP), driving elevated activities of denitrifying enzymes (NAR, NIR, NOS) and higher abundances of associated functional genes (narG, nirS, nosZ). This demonstrates that SPS denitrification is governed not simply by pollution magnitude but by pollution-driven microbial metabolic reconfiguration. This study provides novel insight into SPS-denitrification performance in lakeshore zone with different offshore distances, with critical implications for managing eutrophic and metal-contaminated aquatic ecosystems.

Ground-level ozone (O₃) pollution is a major environmental challenge facing the Yangtze River Delta(YRD) region during the summer and autumn seasons. However, the vertical structure of ozone around large water bodies and its association with the planetary boundary layer (PBL) remain unclear. As a key interface between the Earth's surface and the free atmosphere, the PBL plays a crucial role in ozone formation, dispersion, and vertical transport, necessitating further investigation. This study utilized ozone, wind profilings, ozone precursor NO₂, and concurrent meteorological observation data from July to December 2023 along the eastern shore of Lake Chaohu to systematically analyze the distribution characteristics of ozone and its precursor NO₂ and their interactions with the PBL.The results indicate that: (1) The eastern shore of Chaohu Lake generally meets the standards for a Class I area. Notably, the period from August to October experiences a high incidence of ozone pollution, with daily peak concentrations occurring at 15:00. (2) Correlation analysis revealed that surface meteorological factors such as temperature, sunshine, and air pressure significantly influence ozone levels. During the transition between northeast and southeast winds, ozone-rich air masses from the YRD are advected into the airspace over Lake Chaohu, exacerbating the accumulation of pollutants and enhancing ozone production. (3) High ozone concentrations on polluted days are closely related to the vertical structure of the PBL under stable atmospheric circulation conditions. During such periods, the PBL exhibits higher temperatures, lower wind speeds, and reduced relative humidity. Additionally, the presence of a stabilization layer between 1500 and 3000 m contributes to elevated ozone concentrations below 1300 m. Furthermore, vertical transport through the pollution belt within the height range of 1000 to 1500 m significantly contributes to ozone exceedances. (4) Vertical velocity (ω) under stable weather conditions exacerbates surface pollution by vertically transporting ozone within the boundary layer downward to the surface, and there are temporal differences in the effects of vertical wind shear (VWS) on ozone: weak VWS before 09:00 promotes the accumulation of the precursor NO₂, whereas small VWS after 12:00 increases the risk of surface ozone pollution. In summary, surface ozone concentration is regulated by local photochemical reactions, PBL dynamical structure and regional weather systems at multiple scales. This study reveals for the first time the coupling mechanism between the vertical distribution of ozone and the PBL in the middle and lower reaches of the Yangtze River lakes region, which provides a key scientific basis for the optimization of cross-regional ozone pollution prevention and control strategies.

In this study, the adsorption of Astrazon Blue and Astrazon Red, which are cationic dyes commonly used in the textile industry, from aqueous solution onto commercial activated carbon has been investigated. The effect of various parameters, including initial dye concentration, temperature, stirring speed, contact time, adsorbent dosage, and pH, on the adsorbed dye amount has been investigated using a Taguchi experimental design. For both dyes, the maximum amount of dye adsorbed and the highest calculated signal-to-noise ratio were found to be obtained in adsorption experiments with the following conditions: initial dye concentration of 300 mg/L, contact time of 180 min, initial pH of 9, temperature of 313 K, stirring speed of 170 rpm, and adsorbent dosage of 0.05 g/100 mL. In the determined optimum experimental conditions, the means of adsorbed dye amounts for Astrazon Blue and Astrazon Red were found to be 586.0 and 583.3 mg/g, respectively. It was determined that the equilibrium adsorption data showed a good fit to the Langmuir and Redlich-Peterson adsorption isotherm models. On the other hand, thermodynamic analysis revealed that the adsorption of both dyes on the activated carbon surface occurs with negative Gibbs free energy changes and positive adsorption enthalpy and entropy changes.