环境•农林最新文献

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.

Graphical Abstract

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.