This study focused on the long-term AMD-contaminated paddy soils in the Dabaoshan mining area of Guangdong Province. The distribution characteristics of soil iron phases and iron-bound organic carbon were analysed, combining with high-throughput sequencing to examine the effects of AMD irrigation on soil organic carbon sequestration and the response of soil microbial community structure. The results indicated that: ① AMD irrigation led to soil acidification, with accumulation of iron, sulfur and heavy metals in paddy soils. The contents of TOC in paddy soils showed significant positive correlation with TFe, and OC_Fe. ② AMD irrigation resulted in decreases of soil microbial abundance and diversity. AMD irrigation led to a decrease in the relative abundance of Geobacter in paddy soils, whereas acid tolerant iron and/or sulfur metabolizing bacteria such as Thiobacillus and Thioifustis became the dominant bacteria in paddy soils with the most heavily AMD pollution. ③ RDA analysis identified Fe_p, TOC, and TFe were the most crucial factors influencing microbial community structure. In conclusion, AMD irrigation brought dissolved iron into paddy soils which was beneficial to soil organic carbon preservation. In addition, AMD irrigation resulted in the formation of microbial community structure that closely related to AMD pollution gradient, the form and content of iron and carbon.

Semi-volatile organic compounds（SVOCs）can be easily adsorbed by indoor surfaces and thus are difficult to be removed by ventilation or air purification. Photocatalytic oxidation technology has bright prospects in the field of indoor air purification, but its performance on removing indoor SVOCs is still unclear. In this study, we found that the commonly-used photocatalyst（P25titanium dioxide）could effectively degrade two typical indoor SVOCs（dibutyl phthalate（DnBP）and tri（2-chloropropyl）phosphate（TCPP））under the irradiation of both a 254 nm ultraviolet lamp and a fluorescent lamp, and the degradation process could be described by the first-order kinetic equation. Under the irradiation of fluorescent lamp, DnBP and TCPP were completely degraded within 120 and 42h, respectively, being significantly faster than the removal rate of ventilation and air purification for these two SVOCs. Furthermore, the degradation products and corresponding pathways of DnBP and TCPP were analyzed by gas chromatography-mass spectrometry coupled with proton transfer reaction time-of-flight mass spectrometer.

The discovery of complete ammonia-oxidizing bacteria（comammox）provided a novel direction for improving nitrification efficiency in wastewater treatment systems. The potential of their metabolic pathways and functional genes for efficient nitrogen an d carbon removal from wastewater was demonstrated. However, strategies to achieve robust comammox enrichment remained controversial. Further investigations were required to characterize the specific contributions to ammonia removal and nitrous oxide（N₂O）production during the nitrification process. The technical strategies for efficient comammox enrichment and the impacts of key factors including environmental substrate concentration, dissolved oxygen, operational processes, and temperature on the selective enrichment of comammox were summarized. Chlorate was employed as a specific inhibitor targeting comammox in combination with 1-octyne to construct a dual-inhibitor experimental system, which was capable of clarifying the nitrification contribution and N₂O emission potential of comammox in wastewater treatment systems.

The UV/O₃/PS process was used for the degradation experiments of chloramphenicol, the degradation performance of the combined UV/O₃/PS process, UV/PS, O₃/PS and UV/O₃ processes was investigated, the contribution of major active free radicals to CAP degradation was analyzed for the reaction system, the effects of PS concentration, O₃ concentration, pH, and the common inorganic anions and natural organics on the degradation were examined respectively, the degradation pathway of CAP and the formation potential of disinfection by-products were clarified, also the calculation of energy consumption for the UV/O₃/PS process was discussed. The results showed that the CAP removal by the combined UV/O₃/PS process was 90.41% at 60min. ¹O₂, HO· and SO₄⋅^- were the three main active species in the reaction system, and their contributions to CAP degradation were 53.85%, 25.64% and 12.82% in turn. the increase of PS and O₃ concentrations favored the degradation of CAP, and alkaline conditions could promote the degradation of CAP, co-existing Cl^-, HCO₃^- and humic acid inhibited the degradation of CAP. the degradation mechanism of CAP by the UV/O₃/PS system mainly involved the hydroxylation, amino oxidation and C-N bond breaking or something. The formation potential of trichloromethane and trichloroacetonitrile was significantly increased through CAP pre-oxidation treatment, the formation potential for trichloromethane increased from 30.35µg/L to 48.08µg/L and that of trichloroacetonitrile from 12.31µg/L to 20.97µg/L. Energy consumption evaluation showed that the UV/O₃/PS process has a better overall efficiency.

The scouring of sediment deposits in sewer system constitutes a critical factor in overflow pollution. By integrating rainfall intensity variations, stratified anti-scouring characteristics, and dynamic pollutant transport, a dynamic transport model was developed to evaluate stratified sediment scouring under different rainfall intensities and its impact on water quality transformation. Experimental results demonstrate significant disparities in sediment scouring efficacy across varying rainfall intensities. Under light rainfall conditions, the scouring rate measured 6.04m³/h, primarily removing superficial sediment layers. Moderate and heavy rainfall events induced substantial enhancement of flow shear forces, with pipe discharge reaching 71.08m³/h during intense precipitation, capable of mobilising larger particles from underlying sediment strata. A pronounced "initial phase effect" was observed across all rainfall intensities, characterised by rapid pollutant concentration peaking during precipitation onset. Under heavy rainfall, sulphate concentrations surged to 17.89mg/L within 1min before stabilising at 8.95mg/L, while Total Chemical Oxygen Demand（TCOD）exhibited a swift ascent to 2106.3mg/L followed by stabilisation at 1056.6mg/L. In contrast, light rainfall conditions yielded markedly lower peak values of 10.29mg/L for SO₄^2- and 1100.60mg/L for TCOD, though similarly demonstrating rapid initial concentration escalation followed by gradual stabilisation.

To comprehensively evaluate the reduction potential of diffuse nitrogen pollution under the field-ditch-pond system optimization, a watershed hydrological model was used to simulate the multi-scenario optimization of field ponding water level, ditch, and pond in a typical paddy field watershed. Results showed that different optimizations had different interception effects on diffuse nitrogen pollution, and that interception effects were different over distinct hydrological years. Under the optimization of field ponding water level, the total nitrogen loss from paddy fields after optimizing the drainage water level was reduced by 7.9% to 93.9% compared to conventional water level management, with the nitrogen interception effect being better in dry years than in wet years. Under ditch optimization, the reduction rate of nitrogen loss in the watershed increased from 0.8% to 26.7% after increasing the grass planting density of ditches, with the nitrogen interception effect being better in wet years than in dry years. Under pond optimization, the reduction rate of nitrogen loss in the watershed increased from 10.5% to 18.1% after increasing the catchment area of the pond, with the nitrogen interception effect being better in dry years than in wet years. Under the multi-optimization of the field-ditch-pond system, the interception effect of field ponding water level optimization on watershed nitrogen loss was better than that of pond optimization and ditch optimization. In summary, the multi-optimization of the field-ditch-pond system can effectively control the diffuse nitrogen pollution in paddy field watersheds and could promote the sustainable development of rice production.

This study investigated the relationship between Dicer expression levels and urinary arsenic metabolites both in vivo and in vitro, as well as examined the role of Dicer in cell proliferation. For the epidemiological analysis, workers from a high arsenic-polluted factory in Yunnan Province were selected as the arsenic-exposed group, while residents from nearby villages without arsenic exposure history were recruited as controls. Urinary arsenic species（inorganic arsenic, monomethylarsonic acid [MMA], and dimethylarsinic acid [DMA]）were quantified, and Dicer mRNA expression levels in peripheral blood were measured. It was found that the relative Dicer mRNA expression in the arsenic-exposed group was significantly elevated compared to controls. Furthermore, Dicer mRNA levels were positively correlated with urinary inorganic arsenic, MMA, and DMA concentrations. For in vitro experiments, human bronchial epithelial cells（16HBE）were treated with sodium arsenite（1.5, 3, 4.5µmol/L）or 4.5µmol/L MMA, DMA, or sodium arsenite. Dicer mRNA and protein expression were analyzed by RT-qPCR and Western blot. Additionally, Dicer expression was knocked down in 16HBE cells using siRNA, and cell viability and proliferation were assessed via CCK-8 and EdU assays. It was observed that Dicer mRNA and protein levels in 3 and 4.5µmol/L sodium arsenite-treated cells were significantly upregulated compared to untreated controls, whereas no changes were detected in MMA- or DMA-treated groups. Knockdown of Dicer was shown to suppress cell viability and proliferation. Notably, sodium arsenite exposure combined with Dicer knockdown resulted in a more pronounced reduction in cell proliferation rates.

Employed a SBR to simulate municipal wastewater as the influent matrix and initiated the Nitritation-Enhanced Partial Denitrification-Complete Autotrophic Nitrogen Removal Over Nitrite（N-EPD-CANON）process. The anoxic duration within the EPD system was meticulously adjusted to scrutinize the impact on endogenous nitrite accumulation and the consequent performance alterations within the CANON system. The objective was to elucidate the influence of anoxic time on endogenous nitrite concentration and its subsequent effects on nitrogen removal efficiency, the activity of functional microbial groups, and the structure of microbial communities within the CANON process. The findings revealed that an anoxic duration of 40minutes within the EPD system was optimal for capturing influent organic matter while concurrently promoting the endogenous nitrite to accumulate at a favorable concentration of approximately 4mg/L. Under sustained operational conditions, the CANON reactor achieved a total nitrogen removal rate of 86.43%. The specific anammox activity（SAA）was determined to be 0.82gN/（gVSS·d）, the particular nitrate production rate（SNPR）was reduced to 0.28gN/（gVSS·d）, and the specific ammonium removal rate（SAOR）was recorded at 0.70gN/（g VSS·d）. Additionally, the application of 3D-EEM and PARAFAC techniques to analyze the fluorescence components of EPS in the sludge indicated that the intensification of endogenous nitrite had a beneficial effect on increasing the content of aromatic proteins within the EPS without altering its composition. Microbiota community analysis reveals that Candidatus_Competibacter is the dominant genus in the EPD system, accounting for 24.61%. In contrast, in the CANON system, the relative abundance of Nitrosomonas at 2.67% ensures the NO₂^--N supply for AnAOB, and Candidatus Brocadia, as the main genus of AnAOB, accounts for 13.34%.

The combination of ground remote sensing and UAV remote sensing was used to estimate the nitrogen content of typical grassland vegetation in Inner Mongolia. This experiment was carried out in the grassland ecology research base of Inner Mongolia University from August to September 2023, and the ground ASD spectral data and UAV Resonon data were collected. Based on ASD data, four spectral parameters of vegetation index, hyperspectral characteristic variable, continuum removal variable and wavelet coefficient were constructed, and LASSO was used to screen sensitive parameters. Five models of multiple linear, XGBoost, SVM, ANN and KNN were constructed to estimate the nitrogen content of vegetation. The results showed that the SVM method based on wavelet coefficients was the optimal model（validation set R²=0.72, RMSE and MAE were 0.26 and 0.18, respectively）. Finally, the model was used to estimate and map the UAV Resonon data（validation set R²=0.41, RMSE and MAE were 0.42 and 0.32, respectively）. The research showed that the combination of ASD and UAV images with machine learning algorithms could be used to realize the estimation of grassland vegetation nitrogen content, and was provided basic data and technical support for optimizing fertilization and improving forage quality.

This study focuses on a decommissioned mining area of acid in-situ leaching in Xinjiang. By analyzing long-term groundwater monitoring data, a three-dimensional transient groundwater flow and contaminant solute transport model was developed to simulate the migration of contaminant species（U（Ⅵ）and ）in the ore-bearing aquifer. The study aims to provide a reasonable hydraulic control strategy to ensure the groundwater environmental safety in the decommissioned mining area. The results indicate that the post-decommissioning groundwater flow field is generally consistent with the direction of the natural flow field. High concentrations of U（Ⅵ）and remains extensively in the mining area and gradually migrate and diffuse downstream under the influence of groundwater dynamics. The constructed model successfully reproduces the observed groundwater level trends in the decommissioned mining area and accurately simulates the downstream migration and diffusion of U（Ⅵ）and from within the mining area. This demonstrates that hydraulic control is a crucial measure for ensuring the ecological safety of the downstream groundwater environment in future conditions. Analysis of three hydraulic control pumping schemes revealed that a combined internal and external pumping strategy yielded the best control results. Using a comprehensive evaluation method to quantitatively assess each scenario, the optimal solution was determined to involve installing six pumping wells downstream and three pumping wells within the mining area, each operating at a pumping rate of 60m³/day. This approach achieves effective source reduction within the site and hydraulic containment downstream, keeping contaminant migration within a 50m range at relatively low cost. By employing the developed numerical model to compare and select hydraulic control strategies under future planning conditions, this study provides a scientific basis for decision-making on groundwater environmental safety in the mining area and offers valuable insights for the remediation of similar decommissioned in-situ leaching uranium mines.