Using the Gansu section of the Yellow River Basin as the research object, Fragstats 3.3 software and Pearson correlation analysis method were used to calculate the landscape pattern index of the river buffer zone, analyze the correlation between water quality and landscape pattern indicators, and investigate the factors influencing the water quality of the Yellow River’s main stream and tributaries in Gansu Province. The data included the land use data with the resolution of 30m in 2020, water quality monitoring data, and socio-economic data from 2018 to 2021. The results indicated that:（1）From 2018 to 2021, the water quality of the main stream and tributaries of the Yellow River in Gansu Province were improving, except the Taohe River, where the concentration of water quality indicators was in the increasing trend；however, TN at more than 80% of monitoring sites remained above Class V water quality standards, with significant nitrogen pollution persisting in the Weihe River, Jinghe River, and Zhuanglang River. High concentrations of TN and NH₄⁺-N were mainly distributed in the central and eastern parts of the basin, TP levels were elevated across most areas, and COD was dispersed, with hotspots concentrated in parts of Lanzhou City and central Linxia Hui Autonomous Prefecture.（2）A significant correlation was observed between landscape patterns and water quality indicators. Higher aggregation and connectivity of landscape patches were associated with better water quality, whereas higher levels of fragmentation and dispersion increased the risk of water pollution.（3）Water quality indicators exhibited strong spatial heterogeneity. The driving factor analysis revealed that NH₄⁺-N, TP, permanganate index, and COD were primarily influenced by rural activities, while TN and DO were mainly affected by urban living and industrial production.

This study utilized natural red clay（RC）and 700°C calcined red clay（CRC-700）to form treatment groups combined with submerged macrophytes Vallisneria spiralis（VS）and Ceratophyllum demersum（CD）, aiming to develop a treatment technology effective in controlling sedimentary phosphorus（P）release. The results demonstrated that the VS+CRC-700 treatment group exhibited superior performance in reducing and removing sedimentary P compared to other treatments. Specifically, dissolved reactive phosphorus（SRP）in the overlying water of the VS+CRC-700 group was significantly reduced from 1.38 mg/L to 0.024 mg/L compared to the control group. Additionally, the concentrations of Fe（II）-P and iron-aluminum bound phosphorus（CDB-P）in different sediment layers were maximally decreased by 94 and 488.03 mg/kg, respectively. Meanwhile, the VS+CRC-700 treatment markedly enhanced P immobilization in sediments, with Ca-P content increasing by up to 182.78mg/kg across sediment layers. Furthermore, microbial community analysis revealed that VS+CRC-700 increased sediment microbial abundance by 5403 units, while reducing the relative abundances of Proteobacteria and Bacteroidetes by 16.56% and 33.33%, respectively. These findings collectively suggest that VS+CRC-700 represents a cost-effective and high-efficiency technology for improving water quality in P-polluted systems. Its application demonstrates significant potential in controlling sedimentary P release under weak hydrodynamic conditions.

The Taihangshan-Yanshan region serves as a crucial ecological barrier for the Beijing-Tianjin-Hebei area. Investigating the spatiotemporal patterns of vegetation growth and their influencing factors holds significant importance for implementing ecological conservation and restoration decisions. The MOD13A2.061NDVI dataset was obtained through the Google Earth Engine（GEE）platform, and the kernel Normalized Difference Vegetation Index（kNDVI）was further calculated. The spatiotemporal heterogeneity of vegetation cover was analyzed using the Theil-Sen Median method, coefficient of variation method, and Hurst index method. Subsequently, the optimal parameter geographical detector（OPGD）method was employed to identify the multivariate driving mechanisms behind its spatiotemporal differentiation. Results demonstrated that: From 2001 to 2020, the kNDVI in the study area showed a gradual increasing trend during spring, summer, and autumn, while exhibiting a decreasing trend in winter. The annual mean kNDVI displayed a spatial distribution pattern characterized by "higher values in northern and southern regions, lower in central areas", with significant spatial variability. The area with increased kNDVI（66.36%）was larger than that with decreased kNDVI（33.64%）. Weak anti-persistence and weak positive persistence coexisted, collectively accounting for 99.26% of the total area. Approximately 80% of the region maintained kNDVI fluctuations at moderate or lower levels. OPGD analysis revealed that the primary drivers of kNDVI changes included evapotranspiration, land surface temperature, land use type, soil type, and vegetation type（all with q-values greater than 0.20）. The interaction effects between land surface temperature and annual average temperature, and between land surface temperature and cumulative precipitation demonstrated particularly strong explanatory power, exceeding 0.50 and 0.47 respectively. Higher kNDVI values were observed when evapotranspiration ranged within（634mm, 814mm], land surface temperature fell within [5.2°C, 11.2°C], and urban population remained in（216000, 280000）.

Based on the analysis of the material composition and mercury（Hg）content in the surface sediments of the Yellow River subaqueous delta, the distribution characteristics and influencing factors of Hg in the region were examined. The results showed that the Hg content in the surface sediments ranged from 15.09 to 53.11µg/kg, with an average content of 36.32µg/kg, which was relatively low compared to other domestic and international marine areas. The Hg content in the sediments exhibited a'low-high-low-high' pattern from the shore to the sea, with peak concentrations observed at the shear front and in the fine-grained sediment areas offshore. Elevated Hg levels were also found in the sediments near Laizhou Bay in the southern region. Hg was primarily derived from natural sources but was also influenced by emissions from human activities. Hydrodynamic conditions played a crucial role in controlling the distribution of Hg, with a tendency for Hg to accumulate in fine-grained sediments. The 'filter' effect of the estuary, especially the shear front, significantly influenced the spatial distribution of Hg and its transport to the open sea. The distribution of Hg was also related to its carriers, such as organic carbon, carbonate minerals, and iron-manganese oxides. These carriers directly bound with Hg, affecting its distribution, and also influenced the properties of the sediments, thus indirectly influencing the distribution of Hg.

Hypoxia has become a prevalent phenomenon in the plain river network region. To reveal the causes of hypoxia in these regions, the Sihu Canal in the Hanjiang River Basin, one of China's most important freshwater aquaculture areas, was selected as a case study. The spatiotemporal variations in water quality, including dissolved oxygen（DO）and nutrients, were analyzed for the period 2010~2023, and the spatial distribution of nutrients in water and sediments were investigated. The impact of parameters such as water temperature, ammonia nitrogen, and flow on DO levels in the water was evaluated using a Random Forest model. The results indicated significant seasonal fluctuation in DO levels, which exhibited a 'V'-shaped pattern throughout the year. DO concentrations were relatively low during flood seasons, while during non-flood seasons the requirements for Class III surface water quality were generally satisfied. In 2021, severe hypoxia（DO<2mg/L）was observed, with the annual hypoxic days amounting to 79,116, and 96 at the Yunlianghu, Xinhecun, and Xintan sections respectively. Evident hypoxic zones were identified in the mid- and upstream sections of the Sihu Canal, where DO concentrations ranged from 2.61 to 3.22mg/L. From 2010 to 2023, the water quality of the Sihu Canal consistently ranged from Class IV to Class V, with occasional further deterioration recorded. The main parameters exceeding the standards were identified as DO, permanganate index, ammonia nitrogen, and total phosphorus. The total nitrogen and phosphorus contents in the sediments ranged from 857.70 to 2846.87mg/kg, and 545.99 to 2475.59mg/kg, respectively, indicating that the sediments were subjected to mild to moderate pollution, with tributaries being more polluted than the main canal. High accuracy in predicting DO levels was demonstrated by the Random Forest model, which yielded an R² of 0.995 and an RMSE of 0.2085. Water temperature had a relative importance exceeding 35% in influencing DO levels, followed by pH, ammonia nitrogen, conductivity, turbidity, and flow. To mitigate the hypoxic conditions during flood seasons, it was recommended that the systematic management of the basin be strengthened, the water quality of shrimp-rice and aquaculture drainage systems be improved, and the operation and scheduling of pump stations be optimized.

In response to the current limitations of the Fe²⁺/periodate（PI）system, which is difficult to sustain effective performance and is merely applicable under acidic conditions, a system of visible light（VL）and 3,4,5-Trihydroxybenzoic acid（TA）cooperating with Fe³⁺ for activating PI was constructed. The results indicate that the combination of VL and TA can accelerate the redox cycling between Fe³⁺/Fe²⁺, significantly enhancing the performance of activating PI. The VL/TA/Fe³⁺/PI system can achieve the complete degradation of sulfadiazine（SD）within 30min, with better efficacy under neutral and acidic conditions. Anions such as Cl⁻, NO₃⁻, and SO₄²⁻ have minimal effects on SD removal, whereas the existence of HCO₃⁻ significantly inhibits SD elimination. At the same time, humic acid（HA）exhibits a promoting effect. Quenching tests and electron paramagnetic resonance（EPR）analysis confirmed that hydroxyl radicals（HO•）and singlet oxygen（¹O₂）were the primary reactive species responsible for SD removal. Based on mass spectrometry analysis, 6degradation intermediates were verified, and 3 possible degradation pathways for SD were proposed. Using radish as a model organism for phytotoxicity assessment, it was demonstrated that the toxicity of SD-contaminated water was significantly reduced after treatment. Simultaneously, the system exhibited excellent treatment efficiency in various real water matrices. Furthermore, this system exhibits favourable degradation performance for multiple typical emerging contaminants prevalently existing in natural water bodies, indicating broad application prospects.

The study analyzed the effects of different mulching durations（4 to 19 years）on the characteristics of microplastics in the soil of peanut fields. The results showed that as the mulching duration increased, the abundance of microplastics in the soil tended to rise. Compared with a mulching duration of 4 years, the abundance of microplastics in the soil with a mulching duration of 19 years varied between 660 and 3150 pieces/kg. The abundance of microplastics with a small particle size（<2mm）increased with both the mulching duration and soil depth. Long-term continuous mulching promoted the penetration of microplastics into deeper soil layers, which was specifically reflected in the fact that microplastics with a small particle size accounted for 49.9% in the 20~30cm soil layer. In sampling points with different mulching durations and soil depths, the color of microplastics was predominantly transparent, followed by black, green, and purple, while other colors such as red had relatively lower proportions. The shapes of microplastics included fibrous, foamy, film-like, fragmental, and granular, with fibrous shapes being the most dominant. Moreover, the polymer types of microplastics were diverse, mainly consisting of PE（polyethylene, 34.2%）, PP（polypropylene, 17%）, and PS（polystyrene, 16.3%）. In summary, the increase in mulching duration significantly affected the proportion of transparent microplastics in the soil, but had no significant impact on the types of microplastics and polymers.

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.

Antibiotic resistance was recognized as one of the most critical public health challenges confronted by humanity in the 21 st century. Metal nanomaterials were regarded as potent alternatives in the post-antibiotic era, attributed to their exceptional biocidal efficacy and tunable properties. However, it was demonstrated through recent studies that not only could resistance to nanomaterials themselves be developed by bacteria, but the physiological characteristics of bacteria could also be altered, consequently leading to enhanced antibiotic resistance. The antibiotic resistance variations induced by metal nanomaterials were systematically reviewed, with underlying mechanisms being elucidated through three key aspects: the interfacial interactions between nanomaterials and bacterial membranes, the occurrence of bacterial genomic mutations, and the horizontal transfer of resistance genes. This investigation was designed to establish a theoretical framework for innovating next-generation nano-antimicrobial agents, while simultaneously promoting the application of nanomaterials in combating antimicrobial resistance on a global scale.

CoFe₂O₄@MoS₂ was prepared by the hydrothermal method and used to activate permonosulfate（PMS）for the degradation of ciprofloxacin（CIP）in water. The successful preparation of CoFe₂O₄@MoS₂ was confirmed by the characterization results obtained from SEM and XRD. Degradation results showed that the removal rate of CIP in the CoFe₂O₄@MoS₂/PMS system can reached 74.38% in 120minutes, which is higher than the sum of the individual CoFe₂O₄@MoS₂ and PMS systems, verifying the activation ability of CoFe₂O₄@MoS₂ on PMS. The quenching experiment results indicated that the main oxidative active species in the system are ^●OH、SO₄^●- and ¹O₂, with SO₄^●- and ¹O₂ playing a major role in the degradation of CIP. Based on density functional theory combined with HPLC analysis, eight possible products were obtained and two possible degradation pathways of CIP were proposed. The environmental risks of the degradation products were evaluated and predicted using the TEST program, and it was shown that, compared with the parent compound, most products exhibited reduced acute toxicity, weakened mutagenicity, decreased bioaccumulation and developmental toxicity, and significantly lower ecotoxicity. Additionally, the CIP removal rate of the CoFe₂O₄@MoS₂/PMS system can still reached 60.04% after four cycles, and the XRD results demonstrated that the crystal structure of the catalyst did not undergo significant changes before and after the reaction, indicating the high efficiency and stability of the catalyst.