The aims of this study are to assess the high-value characteristics of vermicompost products derived from organic wastes and to explore their potential as bio-organic fertilizers. For this purpose, 8 samples of sludge-based vermicompost and 16 samples of cow manure-based vermicompost were collected to compare their nutrient content, dissolved organic matter (DOM) characteristics, microbial community structure, and ecological functions. The results showed that both types of vermicompost were rich in water-soluble nitrogen and phosphorus, however, only half of the samples met the organic matter content standard specified in the “Organic Fertilizers” (NY/T525). Cow manure-based vermicompost was weakly alkaline, while sludge-based vermicompost was acidic. The content of humic substances in sludge-based vermicompost was 40.3% significantly higher than that in cow manure- based vermicompost (P<0.01), and the biochemical index and freshness index of DOM in sludge-based vermicompost were significantly higher than those in cow manure-based vermicompost (P<0.001). Additionally, the Chao1index and Shannon index in cow manure-based vermicompost were 1.31 times and 1.10 times higherthan those in sludge-based vermicompost (P<0.001), respectively. Moreover, significant differences in β-diversity of microbial community were observed between two types of vermicompost (P<0.01), particularly in the dominant bacterial genera. The dominant bacterial phyla in both types of vermicompost were Proteobacteria, Bacteroidetes, and Actinobacteria.Functional prediction indicated that the carbon and nitrogen cycling functions of microorganisms in sludge-based vermicompost were more abundant than in cow manure-based vermicompost. In conclusion, the DOM characteristics and microbial community structure in vermicomposts are closely related to theirsource type, with sludge-based vermicompost showing superior nutrient and humic substance content, relative to cow manure-based vermicompost.

Field plot experiments were conducted to study the intercropping systems of the hyperaccumulator Sedum plumbizincicola and passion fruit. Three planting densities of S. plumbizincicola were tested: low (D1: 30cm×30cm), medium (D2: 25cm×25cm), and high (D3: 15cm×15cm). Additionally, two microbial agents, Bacillus megaterium (Bm) and Bacillus mucilaginosus (Bmk), were applied at the medium density (D2). The effects of different treatments on the plant growth, heavy metal accumulation, and phytoextraction efficiency were investigated. The results showed that under the intercropping system, high density planting (D3) significantly increased the aboveground biomass of S. plumbizincicola and its phytoextraction efficiency for soil Cd and Zn, with annual extraction rates increased by 62.5% and 72.7%, respectively, compared with low density planting (D1) (P<0.05). The Cd content in passion fruit pulps decreased with increasing planting density of S. plumbizincicola and met the national food safety standards. Moreover, the application of Bmk in the intercropping system had a better effect on the growth of S. plumbizincicola and its ability to absorb Cd and Zn. Compared with CK, the aboveground biomass of S. plumbizincicola in Bmk treatment increased by 43.2%, and the uptake of Cd and Zn in the aboveground parts increased by 7.02% and 20.9%, respectively. The microbial application significantly reduced the pH value and significantly increased the available Cd and Zn content in both rhizosphere and non-rhizosphere soils, while Bmk had better effect than Bm. In all, this study provides a theoretical basis for improving soil heavy metal remediation under the intercropping system of hyperaccumulators and fruits.

As a core drinking water source in Beijing, the response mechanism of Total Nitrogen (TN) exceedance to Net Anthropogenic Nitrogen Input (NANI) in Miyun Reservoir is not clear. In this study, NANI was constructed based on multi-source data from 2007 to 2023 to systematically reveal the spatial and temporal dynamics of nitrogen input and its influence on TN output in the watershed. The results showed that the average NANI of Miyun Reservoir was 2768.80kg/(km²·a), with an overall decreasing trend year by year, and the high value of the input area was mainly distributed in the east, while the nitrogen input in the west was more stable; fertilizer application dominated the contribution structure of nitrogen input sources for a long period of time (67.32% of the peak value), and the contribution of the net nitrogen input from food was slowly decreasing; and the nitrogen buffer mechanism of the basin weakened the linear response of anthropogenic inputs to TN outputs. The linear response between anthropogenic inputs and TN outputs was weakened by the watershed nitrogen buffering mechanism, with the short-term bioretention capacity (SBI) enhanced by 57.90%, while the long-term buffering capacity (LBI) was reduced by 86.46% due to historical nitrogen accumulation, suggesting that saturated nitrogen retention may exacerbate the risk of water quality in the future. The study clarified the spatial and temporal patterns of nitrogen input and buffer lag effect in Miyun Reservoir, and provided scientific basis for nitrogen control strategy and dynamic early warning.

Valley-type municipal solid waste (MSW) landfill sites were characterized by a large hydraulic gradient, high groundwater flow velocity and rapid contamination migration. It was challenging for traditional permeable reactive barriers (PRBs) to efficiently capture contamination plumes under these conditions. According to the contamination migration characteristics of valley-type landfill sites, a novel passive overflow-PRB was proposed in this paper. The passive overflow-PRB was composed of a low-permeability cutoff wall and a high-permeability PRB, with the PRB situated in the upper-middle section of the cutoff wall. Upstream groundwater would be captured by the cutoff wall, then the groundwater level would be elevated and the contaminated groundwater would be forced through the PRB for remediation. This design was suitable for installation at the downstream outflow of a valley, effectively preventing further migration of the contamination plume off-site, and solving the problem of excessive construction depth required for the PRB. To validate the effectiveness of the passive overflow-PRB, the groundwater ammonium nitrogen (NH₄⁺-N) from two valley-type landfill sites in Guangdong Province and Zhejiang Province was taken as the remediation target. NaCl-modified zeolite was applied as the reactive material of the PRB, and MODFLOW and MT3DMS models were employed to simulate the collection and remediation effects after construction of passive overflow-PRB. The simulation results indicated that the passive overflow-zeolite PRB could effectively prevent the further migration of NH₄⁺-N contamination plume to the downstream, maintaining concentrations below 20.0mg/L or 1.5mg/L for 5years.

The effects of in-situ coverage of aluminum oxide (Al group) and iron oxide (Fe group) on phosphorus release from Erhai Lake sediments were evaluated through an indoor laboratory study. Base on sediment total phosphorus (TP), phosphorus forms, dissolved organic matter (DOM), and sediment water interface characteristic parameters, the differences and mechanisms of phosphorus control effects between the two materials were analyzed. The results showed that compared to the control group (CK group), both the Al and Fe groups significantly inhibited the maximum release amount (Q_max) of TP and reactive phosphorus (SRP), reducing them by 42.61% and 40.64% for TP, 45.04% and 46.29% for SRP, respectively. The downward migration and burial of TP in sediments were promoted by both types of material coverage, while the transformation of active phosphorus in upper sediments (weakly adsorbed phosphorus (NH₄Cl-P), reducible phosphorus (BD-P), and metal-oxide bound phosphorus (NaOH-P)) into inert phosphorus, namely(calcium bound phosphorus (HCl-P) and insoluble phosphorus (Residual-P), was simultaneously enhanced , thereby reducing the direct source of phosphorus release from sediments. The changes in DOM content in the Al and Fe groups followed the same trend as TP content. The molecular weight and aromatic structural complexity of DOM increased in both groups, and the mineralization rate of DOM was inhibited. The degree of DOM humification was enhanced in the Fe group, while the opposite trend was observed in the Al group, where phosphorus release produced by DOM decomposition was reduced. The diffusion boundary layer (DBL) thickness, oxidation-reduction potential (E_h), and decay rate of the sediment water interface in both the Al and Fe groups were all increased. Oxygen penetration depth (OPD) was markedly greater in Fe group than in the CK group, whereas it was lower in the Al group. Overall both materials changed the interface thickness and oxidation environment, increasing the channel resistance for phosphorus release from sediments. These findings demonstrate that both alumina and iron oxide can effectively control phosphorus release from lake sediments, although through distinct mechanisms, providing a scientific basis for selecting in-situ remediation materials in eutrophic lake sediments.

To address the challenge of heightened uncertainty in water-floating garbage trajectory prediction caused by multiple influencing factors, a multi-feature dynamic weighted fusion model for water-floating garbage trajectory prediction was proposed. Firstly, a multi-factor feature dynamic weighted fusion layer was designed to thoroughly analyze the complex mapping relationships among various influencing factors. Secondly, a bidirectional spatial-temporal weighted attention network was introduced to perform weighted fusion of features extracted by BiLSTM, thereby capturing richer temporal-spatial characteristics of drift trajectories. Finally, a learnable nonlinear output layer was proposed to fully integrate information from diverse input factors and trajectory data, significantly enhancing the model's generalization capability and prediction reliability. Experimental results on the Yinggezui Reservoir trajectory dataset show that compared with baseline model, the R² index of the proposed method has improved by 0.1085, and the MAE, MAPE, and MBE indices have decreased by 0.0112, 3.715, and 0.000624. This method can fully integrate multiple factor data and achieve high-precision prediction of the trajectory of water-floating garbage, providing a reliable model for the salvage and management of water-floating garbage.

Based on the long-series normalized vegetation index (NDVI) and climate, topographic and human activity factor data, this study studied the dynamic change characteristics and temporal stability of vegetation NDVI in China's first-class watersheds from 2000~2022 by using Theil-Sen Media trend analysis+Mann-Kendall test, geographic detector and temporal stability, and identified the representative sub-watersheds of nine first-class watersheds in China. The findings indicated that: in terms of time, the NDVI values of vegetation in the nine major river basins of China showed a significant upward trend. Among them, the Yellow River Basin had the highest growth rate of 0.0052a^-1, followed by the Songliao River Basin with a growth rate of 0.0032a^-1, while the Huaihe River Basin had the lowest growth rate, at only 0.0010a^-1. Spatially, the NDVI of vegetation exhibited a declining trend from the southeast to the northwest, and the vegetation change was mainly improved, accounting for 52.02%, and the flow between different levels of vegetation cover was mainly to the higher grades. The representative sub-basins of vegetation stability in the major river basins of China are as follows: Southwest River Basins (No. 35 Lancang River Basin), Inland River Basins (No. 15 Tarim River Basin), Yangtze River Basin (No. 8 Han River Basin), Southeast River Basins (No. 24 Min River Basin), Huai River Basin (No. 16 Yi River Basin), Hai River Basin (No. 32 Daqing River Basin), Songliao River Basin (No. 21 Songhua River Basin), Pearl River Basin (No. 12 Xijiang River Basin), and Yellow River Basin (No. 7 Fen River Basin). Based on the mutation methods of different river basins, it was concluded that the ordered clustering method and the sliding T-test were more suitable for the detection of vegetation change mutations in most of the river basins, among which the Pettt test was suitable for the southeast river basins, the Haihe River, inland rivers, Songliao River and Yangtze River basins, the Huaihe River and Southwest river basins were suitable for the ordered clustering method and the sliding T-test method, and the Yellow River basin was suitable for the sliding T-test.

The Hanjiang River, the largest tributary of the Yangtze River, is crucial for sustaining socio-economic production and human livelihoods in its basin due to its sound aquatic ecological conditions. This study analyzed aquatic ecological survey data from the middle-lower reaches of the Hanjiang River during the dry season (April) and wet season (August) of 2023. Fifty-four candidate metrics were calculated across multiple dimensions, including community composition, biodiversity, pollution tolerance, and functional traits. Unlike traditional biotic integrity index methods, this study did not establish reference sites. Core metrics were screened through statistical analyses (zero-value distribution) and correlation analyses (sensitivity and redundancy analyses), significantly simplifying the screening process. The Index of Biotic Integrity of Benthic Macroinvertebrate (B-IBI) was validated via correlation analysis with reference metrics. Results indicated higher macroinvertebrate biodiversity during the wet season compared to the dry season, with an overall "fair" biotic integrity status. In the dry season, 53.8% of sampling sites were classified as "fair", while 53.8% achieved "good" status during the wet season. Regression analysis identified pH, total phosphorus (TP), and water temperature (WT) as significant factors influencing B-IBI. This systematic assessment provides foundational data for ecological conservation and restoration in the Hanjiang River Basin.

This study focused on the high-hydrodynamic sandy shoal Sanba Tan and the slow-flow sedimentary clay shoal Wugui Zhou in the Jingjiang section of the Yangtze River. The response mechanisms between the composition of SDOM and phosphorus forms were analyzed using EEMs-PARAFAC and sequential extraction methods. Significant compositional differences were observed between the SDOM from Sanbatan and Wuguizhou. Sanbatan was dominated by protein-like components, whose high biological activity, coupled with a high proportion of Fe/Al-P, was found to jointly govern the distribution of phosphorus forms. In contrast, the SDOM from Wuguizhou was primarily characterized by humic-like components, whose high aromaticity and strong chelating capacity were identified to promote the accumulation of organic phosphorus, which was significantly higher than that in Sanbatan. A significant negative correlation was observed between protein-like components and Fe/Al-P (P<0.05), while the humification index was significantly positively correlated with organic phosphorus (P<0.05). These results suggested that SDOM influences phosphorus forms through two primary pathways: competition with metal oxides for adsorption sites and alteration of microbial metabolism. At Sanba Tan, SDOM was more readily precipitated with iron-aluminum oxides, thereby retaining more Fe/Al-P. Conversely, the low-to-medium molecular weight protein-like SDOM in Wuguizhou accelerated the decomposition and mineralization of organic phosphorus. The influence of SDOM on phosphorus forms in sandbars of the mid-Yangtze River was elucidated for the first time in this study, providing theoretical support for the phosphorus trapping function associated with the hydrological regulation of large rivers.

The dynamic changes of soil organic matter (SOM) in alpine ecosystems were investigated using lignin as a molecular marker. Soils from a swamp meadow (WQZ) and a subalpine meadow (AMX) in Hongyuan County, on the northwestern Sichuan Plateau, were analyzed to examine the vertical distribution, degradation state, and environmental drivers of lignin within the soil profile. The results indicated that: In AMX, soil pH was observed to increase with depth, while water content remained low. Both SOM and lignin contents were found to decrease with depth, and soil texture exhibited clear vertical variation. In contrast, WQZ soils showed minimal inter-layer pH variation and high water content ((3times that of AMX). Affected by seasonal waterlogging, SOM and lignin in WQZ initially decreased and then increased with depth. All WQZ profiles were identified as clay loam, with fine particle content exceeding 90%. High lignin content in the AMX surface layer was attributed to root input and declined markedly with depth. In WQZ, long-term flooding was associated with lignin accumulation in deeper layers via leaching or bioturbation, resulting in higher relative lignin contribution to SOM at depth compared to surface layers. Ratios of guaiacyl (Ad/Al)v and syringyl (Ad/Al)s monomers in both soil types exceeded 0.6across all layers, indicating significant oxidative degradation of lignin side chains, which intensified with depth. Demethylation/methoxylation degradation was more pronounced in AMX than in WQZ. Lignin stability was regulated by soil texture: absolute lignin content (Σ8) was higher in clay silt, while sand content was positively correlated with the lignin contribution to SOM (Λ8) within the same layer. Prokaryotic and eukaryotic abundances were influenced by soil water content and pH. Proteobacteria dominated the surface layer of AMX, whereas Acidobacteria were more abundant in deeper layers. In WQZ, Chloroflexi were enriched with depth, and basidiomycete abundance was significantly higher in AMX than in WQZ.