A self-drive weak electric strengthening constructed wetland（SECW）, which was renovated from a hybrid subsurface constructed wetland（HCW）based on ANAMMOX, was established in this study, and its operational performance was thoroughly investigated. Further, the microbial characteristics in the system during the steady operational period were explored, and the nitrogen transformation pathways were also analyzed and elucidated. The results showed that, prefabrication of electroactive biofilms and appropriate layout of the electrodes not only simultaneously enhanced electrode-dependent ammonium oxidation and cathodic denitrification in the SECW, but also significantly increased the abundance and activity of anaerobic ammonium-oxidizing bacteria in its substrate layer. Consequently, a multi-path nitrogen removal system based on ANAMMOX was formed in the device, thereby significantly improving the nitrogen removal performance of the SECW. When the electrode configuration was adopted as “double cathode-single anode” and the hydraulic loading rate（HLR）was 0.08m³/（m²·d）, the SECW exhibited optimal performance. Specifically, its COD, TP, TN, and NH₄⁺-N removal rates could reach up to（91.39±3.09）%,（93.64±1.15）%,（91.67±2.77）%, and（94.34±2.72）%, respectively. Additionally, the mean output voltage and power density of the system respectively maintained at（816.45±8.44）mV and 651.96W/m³.

Based on core sampling, sequential extraction procedure in the laboratory, correlation analysis between sediments and groundwater, and mineral saturation index（SI）of groundwater, this paper explored the distribution, form and influencing factors of RIS in Quaternary sediments in the middle and lower reaches of Chaobai alluvial-proluvial fan, in Beijing. Results showed that the content of RIS in the study area followed a descending order of: Pyrite-S（CRS）>essential sulfur（ES）>acid volatile sulfide（AVS）, among which CRS accounting for 80.1%, ES and AVS accounting for 13.4% and 5.56% respectively. 67% of samples had CRS/AVS value higher than 3. The RIS content in sediments in the upper reaches was lower than that in the lower reaches, and RIS contents in the four aquifers from shallow to deep were 84.3, 37.4, 39.1 and 10.5mg/kg respectively, showing an overall decreasing trend. The results of RDA and correlation analysis indicated that the TOC content, CRS/AVS value and water content in sediments were crucial factors affecting the content and form of RIS in the study area. Specifically, the content of RIS was also affected by the groundwater pH value, iron/sulfur ratio and hydrogeological conditions, and the form of RIS was affected by the COD_Mn and ORP of groundwater. The SI value of FeS in groundwater fluctuated around 0, and the SI value of FeS₂>0. In summary, RIS in the sediments of the study area is basically unaffected by human disturbance, and the activity and bioavailability of sulfide are low. The sediments may affect the concentrations of sulfate, sulfide, iron and arsenic in groundwater mainly through AVS precipitation/dissolution and ES disproportionation reaction.

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.

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.

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）.

The Net Anthropogenic Nitrogen Input (NANI) model was utilized to estimate nitrogen inputs to Quzhou for the period from 2003 to 2022, and its spatial and temporal patterns, variations in components, and determining factors were examined. The results indicated that the average NANI for Quzhou over the past two decades was 12925kg/(km²·a), with a peak of 15698kg/(km²·a)in 2011. The spatial distribution was found to demonstrate an east-high and west-low pattern, which was consistent with land-use configurations. The predominant component of NANI was nitrogen fertilizer, which contributed 27% to 41%, followed by net nitrogen input from food/feed at 22% to 42%, atmospheric nitrogen deposition at 21% to 33%, and nitrogen fixation at 7% to 11%. The variations in NANI were primarily driven by nitrogen fertilizer application between 2003 and 2008, food/feed inputs between 2009 and 2014, and atmospheric deposition in recent years. Strategies were proposed to mitigate NANI, including promoting new energy vehicles, reducing nitrogen fertilizer application to align with standards of agriculturally advanced nations, and regulating livestock and poultry farming to match local demand. It was anticipated that these measures would decrease NANI by approximately 833, 893, and 896kg/(km²·a), respectively, achieving a cumulative reduction of about 2622kg/(km²·a), positioning it among the lower levels globally.

Based on field data from 2019 to 2022 in the South Tiaoxi River Watershed in the upper reaches of the Taihu Lake Basin, redundancy analysis (RDA) and non-parametric breakpoint analysis (nCPA) were employed to analyze the relationships between riverine nitrogen (N) concentrations and landscape pattern indices at different buffer scales, and identity the critical landscape threshold ranges affecting the river nitrate (NO₃^--N) concentration. The results showed that the total nitrogen (TN) concentration in the South Tiaoxi River exceeded the Class V surface water quality standard, with NO₃^--N as the predominant N pollutant. During the wet season, the concentrations of TN, dissolved total nitrogen (DTN), NO₃^--N, and dissolved organic nitrogen (DON) were significantly higher than those in the dry season, whereas ammonium nitrogen (NH₄⁺-N) concentrations were lower. N concentrations were lower in the upstream compared to downstream. The landscape pattern indices in the buffer zones of 400m and 200m explained the largest variance in river N concentrations during the wet and dry seasons, respectively (89.49% and 90.97%). Based on the identified key thresholds of landscape pattern indices for significantly reducing the risk of NO₃^--N pollution in the watershed, the following suggestions are provided: the proportion of farmland, construction land, and Shannon diversity index (SDHI)in the buffer zone of 400m should be controlled within 0.25%, 1.75%, and 0.77, respectively; and the proportion of farmland and edge density (ED) in the buffer zone of 200m should be kept within 0.5% and 39m/hm², simultaneously with the proportion of forest area exceeding 91.0%.

The weathered soil profiles were taken as the research objects from paddy and upland fields, which are typical agricultural lands in the carbonate rock regions of South China. The sources of soil heavy metals were traced via Pb isotope composition, and the vertical distribution and influencing factors of eight common types of heavy metals in the farmland soil profiles were systematically analyzed. The results revealed that the weathering of parent rocks was the main source of soil heavy metals in the study area, and the contents of heavy metals in the two profiles were found to be higher than the soil background value (0.056mg/kg). The enrichment of Cd tended to occur in the surface layer (0.49~2.15mg/kg) and the middle layer(0.75~1.87mg/kg) of the soil profiles, while that of the other elements tended to occur in the middle layer. The physicochemical properties and the mineral compositions of the soils, as well as the changes in the redox conditions exerted important impacts on the migration of heavy metals. The secondary enrichment of heavy metals in the soil profiles from the study area was attributed to the weathering process of carbonate rocks, while the impact of the leaching process on the migration and enrichment of heavy metals was more significant in the profile from the paddy field.

Lrovincial panel data from 2011 to 2021 were leveraged in this study to examine the effectiveness and underlying mechanisms of digitalization in promoting the coordinated development of mineral resources and ecological conservation from the perspective of regional development disparities. It was indicated by the findings that, overall, a moderate upward trajectory had been shown in the level of coordinated development of mineral resources and the environment in China. However, significant geographical heterogeneity persisted, with the southeastern coastal regions being outperformed by the central and western areas. This coordinated development was significantly promoted by digitalization, a conclusion that was remained robust even after addressing endogeneity and conducting sensitivity analyses. Furthermore, industrial structure upgrading and improvements in green innovation capabilities were identified as key mediating factors through which coordinated development was facilitated by digitalization. It was also revealed by this study that the impact of digitalization varied across different regions, with China’s southeastern regions being benefited more substantially. Based on this analysis, several recommendations were proposed, including investments in digital infrastructure and technologies being enhanced; the pivotal role of digitalization being reinforced; the green transformation of the industrial structure being advanced; and targeted regional development strategies being developed.

A new block filter material with well-developed pores and stable chemical properties was prepared from a biomass ash by short-term and high-temperature sintering. The phosphorus adsorption properties, as well as the kinetics and thermodynamic behaviors, of this material were investigated in this paper. The results of the static adsorption experiments show that the biomass ash filter achieved higher phosphorus adsorption per unit under conditions of higher initial phosphorus concentration, higher reaction temperature, longer adsorption time, or lower solid-liquid ratio. Among these parameters, the solid-liquid ratio was the primary controlling parameter affecting phosphorus adsorption by the filter material. The maximum adsorption per unit of the filter material reached 7.72mg/g, when the initial concentration of phosphorus was 90mg/L, the reaction temperature was 55℃, the adsorption time was 1250min, the pH was 3, and the solid-liquid ratio was 1:200(g:mL). The surface of the material exhibited a heterogeneous structure, and its phosphorus adsorption was primarily driven by multilayer physical endothermic adsorption, supplemented by monolayer or multilayer spontaneous chemical adsorption. Under the dynamic adsorption conditions, the phosphorus adsorption capacity of this filter material per unit was 9.8, 22.27 and 27.22 times that of three common commercial filter materials, including coconut shell biochar, ceramsite and natural zeolite, respectively. This indicates excellent adsorption properties, enabling water purification while achieving biomass ash disposal and recycling, making it highly valuable for promotion.