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.

Given high concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH₄⁺-N), suspended solids (SS), and poor biodegradability of concentrated swine farm wastewater, a combined treatment process of "pretreatment-biochemical treatment- advanced treatment" was employed in this study, specifically designed as "solid-liquid separation → anaerobic fermentation → A/O → MBR." By comparing influent characteristics and pollutant removal efficiency between summer and winter, the energy consumption and greenhouse gas (GHG) emission profiles of the system were systematically analyzed. The average effluent COD and TN in the summer were significantly lower than those in the winter (711.21mg/L and 61.78mg/L, respectively), indicating that low temperature significantly inhibit the treatment efficiency. The A/O unit dominated energy usage, with a consumption of 7.65 (kW·h)/m³, accounting for 56.48% of total energy demand. The annual GHG emissions totaled 1364.41t CO₂-eq, with an emission intensity of 15.53kg CO₂-eq/m³. The emission intensities per unit COD and TN removed were 1.33kg CO₂-eq/kg COD_removed and 10.89kg CO₂-eq/kg TN_removed, respectively. Further analysis revealed that external electricity consumption contributed to 72.98% of total GHG emission, followed by nitrous oxide (N₂O) release (25.99%). Through the regulation of seasonal process parameters, the development of multi-mode operation strategies, and the integration of online monitoring technologies, the precise control of the treatment process is optimized to achieve the goals of energy saving, consumption reduction, and low-carbon operation.

The soil-water partition coefficient (K_d) of per- and polyfluoroalkyl substances (PFAS) was predicted using machine learning (ML) models, and their partitioning behavior in soils was elucidated. A dataset comprising 1,227 samples of 47 PFAS was employed, with 16 PFAS physicochemical properties and soil parameters used as input features. It was demonstrated that the lgK_d values ranged from -1.40 to 3.95. When the number of CF₂ groups exceeded 5and the molecular weight (MW) was greater than 400g/mol, significant linear relationships were observed between lgKd and both the CF₂ number and MW, with R² values of 0.96 and 0.94, respectively. The influence of soil properties on PFAS adsorption was found to be dependent on the type of PFAS: non-zwitterionic PFAS were mainly affected by organic carbon content and silt content, whereas zwitterionic PFAS were primarily influenced by silt and sand content. After parameter optimization, the ML model exhibited good predictive performance, achieving an R² of 0.85, an RMSE of 0.35, and an MAE of 0.26. MW, organic carbon content, water solubility (lgS), and net charge density were identified as the most important features, with contribution rates of 31.6%, 29.8%, 19.7%, and 10.0%, respectively. Three-dimensional interaction analysis indicated that when soils with high organic carbon content, high cation exchange capacity (CEC), and low pH were combined with PFAS of large MW, lgK_d exceeded 0.40, reflecting strong adsorption. Conversely, under conditions where CEC was below 8.00 cmol/kg, organic matter content was less than 1.00%, and MW was below 380g/mol, lgK_d was lower than 0.40, indicating weaker adsorption and higher potential for environmental migration. The findings provide a reliable tool for predicting the adsorption behavior of PFAS.

We chose a petrochemical park in Beijing-Tianjin-Hebei as the research target, and five representative sites were selected for sampling and analysis. 85 volatile organic compounds (VOCs) were detected and their impacts on the environment and health were evaluated. The results showed that the concentration of total volatile organic compounds (TVOCs) were 546.0~4472.2μg/m₃, in which alkanes and alkenes were the dominant group, followed by aromatics and halocarbons. Compared with the diurnal variation of VOCs components at each site, the time of peak and valley values appearing were different, and the typical species were different. Additionally, OFP in the synthetic rubber area was the richest (13239.8μg/m₃). The contribution of alkenes to OFP was the highest (62.8%~90.5%), followed by alkanes (3.8%~34.8%) and aromatics (2.2%~22.1%). Otherwise, only the synthetic rubber area was polluted by odor, 1,3-butadiene (0.68) and n-hexane (0.30) were the main VOCs species that produced odor. Moreover, the health risk associated with each site was assessed by the US EPA method, indicating that the non-cancer risk of synthetic rubber and cancer risk of oil refining were higher than those of other sites.

Based on the monitoring data of 47 typical fine chemical in-process sites in Shanghai, the pollution of soil and groundwater in this industry was analyzed, the health risk of pollutants was evaluated, and high-priority pollutants were screened. The findings revealed that the industries with the highest pollution risk were those involved in basic chemical raw material manufacturing, pesticide manufacturing, paint and similar product manufacturing, and specialty chemical product manufacturing, collectively representing 70% of the contaminated sites. In comparison, the chemical raw material manufacturing industry exhibited a pollution risk of 54.55%, while the daily chemical products manufacturing industry showed the lowest pollution risk (0%). The most frequently detected contaminants in the soil and groundwater included arsenic, lead, mercury, nickel, zinc and total petroleum hydrocarbons (TPH), which were present at relatively low concentrations. In contrast, benzene derivatives (BTEXs), polycyclic aromatic hydrocarbons (PAHs), and most chlorinated hydrocarbons (CAHs) were detected in small areas of certain sites, indicating more severe contamination levels. Furthermore, cyanides, antimony, manganese, and tetrachloroethylene were found in larger areas of certain sites, representing the highest contamination levels. The pollution profile of the basic chemical raw material manufacturing industry was the most complex, involving cyanide, antimony, arsenic, manganese, mercury, CAHs, PAHs, and TPH. On the other hand, pesticide manufacturing, paint and similar product manufacturing, and specialty chemical product manufacturing industries were primarily contaminated by CAHs and BTEXs. A notable observation was the evident soil-water compound pollution phenomenon involving chlorinated hydrocarbons and benzenes. Through comprehensive environmental exposure and human health risk assessments, the following were identified as high-priority soil pollutants: arsenic, chloroform, 1,2-dichloroethane, benzo[a]pyrene, antimony, vanadium, trichloroethylene, lead, carbon tetrachloride, and naphthalene. For groundwater, the high-priority pollutants included trichloroethane, tetrachloroethylene, cyanide, 1,2-dichloroethane, benzene, methylene chloride, nickel, antimony, manganese and trichloroethylene.

Cooperative strategies that mitigate competition among dominant functional microorganisms are crucial for efficient nitrogen and phosphorus removal in wastewater treatment. This study investigated a novel single-stage sequencing batch reactor operating under an anaerobic/anaerobic/oxic/anaerobic (A/A₁/O/A₂) mode for 100days to regulate the dynamic balance of phosphorus-accumulating organisms (PAOs), denitrifying PAOs (DPAOs), and denitrifying glycogen-accumulating organisms (DGAOs). The optimized system, featuring a recycle loop and reduced aerobic phase duration, achieved nitrogen and phosphorus removal efficiencies of (95.13%±0.35%) and (94.70%±0.96%), respectively. Mechanistic analysis suggested that the A₁ phase created an anoxic environment conducive to DPAO-mediated denitrifying phosphorus removal, while the A₂ phase supported DGAO-driven denitrifying nitrogen removal using polyhydroxyalkanoates (PHAs) and glycogen (Gly). Extracellular polymeric substance (EPS) analysis revealed increases of 35.38mg/gVSS in protein (PN) and 12.39mg/gVSS in polysaccharide (PS) content, enhancing sludge aggregation. Microbial community analysis demonstrated significant enrichment of Dechloromonas and Ca. Competibacter, with their abundances increasing from 2.24% and 1.53% in R1to 7.61% and 7.94% in R2, respectively. The A/A₁/O/A₂ mode effectively created a synergistic environment for key DPAOs and DGAOs, achieving superior nitrogen and phosphorus removal performance compared to conventional modes.

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.

To investigate changes in the emission characteristics of key pollutants following the transition from household coal-burning to biomass clean heating in the Fenwei Plain, field measurements were conducted in rural areas of Xianyang using a variety of residential biomass-burning devices. Results showed that, in automatically fed pellet stoves, particulate emissions were dominated by PM_2.5, with emission factors for PM_2.5 and PM₁₀ of 1.14g/kg and 1.28g/kg, respectively, significantly lower than those of traditional stoves. Water-soluble ions in PM_2.5 were dominated by K⁺ and Cl^-, accounting for 81.5 %~94.3 % of total ionic mass, which was 25.9 %~69.6 % higher than that in traditional stoves. Due to the use of cleaner fuels and more efficient combustion, the total carbon (TC) emission factor in PM_2.5 from pellet stoves ranged from 0.1to 0.4g/kg, in contrast to 0.6~3.6g/kg for traditional stoves. Levoglucosan (LG) in PM_2.5 from pellet stoves showed the lowest emission factor, with a lower LG/OC ratio than that of traditional stoves, indicating a reduced contribution of advanced stoves to organic carbon aerosol emissions. By integrating the experimentally derived LG emission factors into an established empirical model, we estimated that the clean-heating transition had reduced the contribution of residential biomass burning to organic carbon aerosol by approximately 6.4 %.

The remediation effect of Robinia pseudoacacia L. intercropped with Solanum nigrum L. and Pteris vittate L. on Cd and As contaminated soil was studied through a pot experiment. The results showed that the intercropping of R. pseudoacacia L. could promote the growth and the uptake of Cd and As in S. nigrum L. and P. vittate L., and reduce the content of Cd and As in soil, as well as enhance soil enzyme activities. Compared with the monocultures of S. nigrum L. and P. vittate L., the whole biomass of S. nigrum L. and P. vittate L. was significantly enhanced (P<0.05) by 50.4% and 86.2% when intercropped with R. pseudoacacia L. Meanwhile, the contents of Cd and As in the leaves of S. nigrum L. were significantly enhanced (P<0.05) by 78.4% and 260.7%, respectively. The total accumulation of As in aboveground parts of all plants under the intercropping of R. pseudoacacia L. with S. nigrum L. and P. vittate L. was significantly enhanced (P<0.05) by 1.11 and 2.17 times compared with the monocultures of R. pseudoacacia L. or S. nigrum L., and the total accumulation of Cd was significantly enhanced (P<0.05) by 1.89 and 15.72 times compared with the monocultures of R. pseudoacacia L. or P. vittate L. Moreover, the contents of available Cd and As in soil under the intercropping of R. pseudoacacia L. with two hyperaccumulators were significantly reduced (P<0.05) by 23.6% and 17.0% compared with the control, respectively. Meanwhile, the contents of soil organic matter and alkaline hydrolysis nitrogen were significantly enhanced (P<0.05) by 46.2%~83.2% and 18.5%~26.4% as compared with the monocultures, the activities of soil catalase was significantly enhanced (P<0.05) by 43.7%~53.0% compared with the monocultures of R. pseudoacacia L. or P. vittate L., the soil sucrase and urease activities were also significantly enhanced (P<0.05) by 11.5%~28.4% and 20.6%~36.4% compared with the monocultures of R. pseudoacacia L. and S. nigrum L., respectively. The results suggested that the intercropping of R. pseudoacacia L. with two different types of hyperaccumulator could effectively uptake and accumulate Cd and As to reduce the bioavailability of Cd and As in the contaminated soil, and effectively improve the soil environmental quality, which could be considered as a promising intercropping model for the simultaneous remediation of Cd and As contaminated soil in mining areas.

Based on the methodology of life cycle assessment (LCA), the carbon footprint of the typical wind power system with generation and electricity storage (WPSGES) in China was calculated, so as to identify the reduction potential of carbon emission from life cycle stages. The results showed that the carbon footprint of WPSGES was 8.44gCO₂/(kW·h), which mainly came from the manufacturing process by 6.25gCO₂/(kW·h)(74.05%). Such processes as construction, operation, and end of life only contributed 1.04, 1.91 and -0.74gCO₂/(kW·h), respectively. It was also confirmed that expanding the system boundary, including power generation and storage, could reduce gross carbon footprint of WPSGES.

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.

Using meteorological station observations, ERA5-L and reanalysis data, and Landsat remote sensing imagery from 2010 to 2023, we analysed the spatiotemporal characteristics of dust storms in the Ebinur Lake Basin of Xinjiang Uygur Autonomeus Region, northwest China. The generalized grey correlation model was applied to quantitatively assess the influence of surface wind speed, soil moisture, and vegetation coverage on the frequency of dust storm occurrences. The results showed an overall upward trend in dust storm days during 2010~2023 (+0.08d/a). In particular, there was a significant increase from 2010 to 2014 (+0.60d/a), followed by a short decline from 2014 to 2017 (−0.70d/a), and a rise after 2018(+0.31d/a). Spring was identified as the peak season for dust storm occurrences, with a lower frequency observed in summer and autumn, and no recorded events in winter. Spatially, the Jinghe meteorological station emerged as the high-frequency centre over the past 14 years. Compared with the late 20th century, the standard deviation of annual dust storm days across the five meteorological stations decreased by 88.42%, indicating a substantial reduction in regional disparities. It revealed that surface wind speed was the most critical driver of dust storms. Soil moisture was the second most influential factor, showing a distinct seasonal lag effect, while vegetation coverage exerted a comparatively minor influence on dust storm occurrence.

In view of the characteristics of Ultisols (red soils) in southern China, this study developed two types of rice-specific biochar-based fertilizers (BBOF: bio-organic-inorganic biochar-based fertilizer; BBF: inorganic biochar-based fertilizer) using rice straw biochar as the base and coating technology. Pot and field experiments were conducted to evaluate their effects on soil chemical properties, microbial communities and rice yield under different pH value, nutrient statuses, and cadmium (Cd) pollution levels. Conventional fertilizer (CF) was used as the control, with three carbon treatments for experiments: direct biochar application (BC), BBOF, and BBF. The results showed that both BBF and BC improved rice yield under field conditions, with BBF enhancing the three key yield components; however, BBF had limited effects on soil improvement. BBOF and BC significantly increased soil pH and soil organic carbon contents(SOC) in the weakly acidic (WA) soil and the strongly acidic soil (SA) with Cd pollution(P<0.05), demonstrating effective acid regulation and carbon sequestration, but had limited effects in low-nutrient acidic (LN) soils. The impact of carbon treatments on soil nutrients varied with soil type: in WA soils, all three treatments significantly increased available phosphorus (AP), available potassium (AK), and dissolved organic carbon (P<0.05); in SA soil, AK was significantly reduced (P<0.05); and in LN soil, ammonium nitrogen(NH₄⁺-N) and nitrate nitrogen levels were notably altered, with BC also significantly increasing AK content (P<0.05). Other soil properties showed no significant response to biochar treatments. Compared with BC, biochar-based fertilizers reduced the amount of exogenous biochar applied and thereby decreased soil Cd input, indicating higher environmental safety. Microbial community analysis revealed that none of the biochar treatments had significant effects on fungal communities (P>0.05), but all affected bacterial communities, with an impact intensity order of BC>BBOF>BBF and a soil bacterial communities response order of LN>SA>WA. Both BC and BBOF regulated bacterial communities in a similar way by significantly increasing the relative abundances of key phyla (Myxococcota, Methylomirabilota, and Acidobacteria) and important functional families (Rokubacteriales_unclassified, Anaeromyxobacteraceae, Bradyrhizobiaceae, and Nitrospiraceae), while significantly decreasing the relative abundances of Planctomycetota (phyla level) and Subgroup_7_unclassified and Isosphaeraceae (family level) (P<0.05). Correlation and redundancy analyses indicated that shifts in soil bacterial communities were closely related to changes in soil chemical properties, with different driving factors identified across soils: AP in WA, SOC in SA, and NH₄⁺-N in LN. This suggests that the regulatory effects of carbon treatments are highly soil-dependent. In conclusion, the bio-organic-inorganic biochar-based fertilizer demonstrated advantages in improving soil environmental conditions and regulating microbial communities in rice-growing red soils, showing potential to replace direct application of biochar. However, its yield enhancement effects and application strategies require further study and optimization.

Based on the statistical data of environmental emergencies directly dispatched by the Ministry of Ecology and Environment from 2005 to 2022, this study used the standard deviation ellipse and mean center to explore the spatiotemporal variability of environmental emergencies, the results showed that the total quantity of environmental emergencies in China exhibited a downward tendency. The spatial mean center of environmental emergencies moved to the southwest of China, spanning a total distance of 734 kilometers in the past 17years, Hubei and Shanxi provinces had replaced Zhejiang, Guangdong and Jiangsu provinces as new high-incidence regions. Through the analysis of the characteristics of environmental emergencies, including the causes, pollution media and pollutants, it is found that production safety accidents were the primary cause of environmental emergencies, accounting for 45.12% of the total, followed by traffic accidents, which had surpassed production safety accidents in proportion over the past two years. Water pollution incidents were the most frequent environmental emergencies, and among the particularly major and the major environmental emergencies, water pollution incidents accounted for about 77.55%. Petroleum and heavy metals were two common pollutants in environmental emergencies, accounting for 16.31% and 5.88% of the total incidents, respectively. In the major and above level environmental emergencies, the proportion of heavy metals was higher than that of petroleum.

A total of 78 water samples from mesotrophic and eutrophic urban lakes in Nanjing, Jiangsu Province, China were systematically analysed using three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) to characterize dissolved organic matter (DOM) composition and sources as well as their links with water physiochemistry parameters. This study was designed to unravel the effects of eutrophication on the fluorescence characteristics of DOM and its influence pathway. Three distinct fluorescent components were identified: anthropogenic-derived humic-like substances (C1), terrestrial humic-like substances (C2), and microbial-produced protein-like substances (C3). Eutrophic urban lakes exhibited significantly higher fluorescence intensities in both C2 and C3 relative to mesotrophic urban lakes. Fluorescence indices confirmed dual DOM sources-terrestrial inputs and autochthonous production. Meanwhile, although the humification index of DOM in mesotrophic urban lakes exceeded that in eutrophic urban lakes, the humification index of DOM was below 1.0 for all samples. Moreover, the biological index of DOM exhibited an increasing trend with the elevation of trophic status of water column. Additionally, significantly elevated Chla concentration were observed in eutrophic lakes compared to mesotrophic lakes. Strong positive correlations were identified between Chla concentration and the fluorescence intensity of C2 and C3 components alongside the biological index of DOM, suggesting that eutrophication may induced autochthonous DOM by stimulating algae reproduction.

Volatile organic compounds (VOCs) were identified as chemicals that caused odor pollution in cars. Nanostructured water ion (EWNS) technology was demonstrated to be capable of producing large amounts of hydroxyl radicals to degrade VOCs, though systematic research on odor VOC removal had not been conducted. In this study, VOCs components from 9cars were first analyzed offline using TD-GC-MS, and the main odor VOCs in actual car interiors were determined through the comprehensive scoring method. A mixture gas containing the average concentration ratio of detected odor VOCs was then introduced into the experimental vehicle, where degradation efficiency was evaluated using EWNS technology. Human health risk assessment was also performed. The results revealed that aliphatic compounds were detected most frequently (7species) in car interior VOCs, while aromatic compounds were found to have the highest detection rate and concentration. Through odor identification scoring, xylene, toluene, ethyl acetate, o-xylene, n-butanol, and hexanal were selected as representative odor VOCs. After EWNS treatment, significant removal effects were observed for all representative odor VOCs, with toluene removal rate being recorded at 92.8%. However, EWNS degradation efficiency was found to vary with placement locations in the vehicle, where better removal effects were achieved in rear positions compared to front positions, potentially associated with hydroxyl radical diffusion efficiency. Meanwhile, the carcinogenic risks of benzene and ethylbenzene were significantly reduced, transitioning from carcinogenic risk to risk-free status.

Analyzing the spatiotemporal variation and influencing mechanisms of dry deposition is crucial for identifying pollution sources, atmospheric pollution control, soil environmental management, and agricultural pollution prevention. Focusing on the Xiangjiang River Basin, a vital grain producing region in China, this study estimated PM_2.5 dry deposition fluxes using empirical parameterization formulas and multi-source data, including remote sensing PM_2.5 concentrations, ERA5 reanalysis meteorological data, and ground-based monitoring. The long-term spatiotemporal characteristics of dry deposition across the basin and three zones delineated by three lines for land use (agricultural zones, ecological preservation zones, and urban development zones) were investigated. Furthermore, the random forest model was employed to quantify the contributions of influencing factors and elucidated the dominant mechanisms driving dry deposition. Results show thatthe dry deposition fluxes presented a spatial pattern of high in the north and central areas, low in the south and periphery. Urban development zones had the highest dry deposition flux (1.42g/m²), followed by agricultural zones (1.06g/m²) and ecological preservation zones (0.80g/m²). Since 2000, dry deposition fluxes have shown a declining trend at a rate of -0.017g/(m²·a), with significant decreases in high PM_2.5 concentration areas. Residential emissions (2.43±0.04), air temperature (0.71±0.01), industrial emissions (0.69±0.02), and relative humidity (0.59±0.01) were identified as dominant factors influencing PM_2.5 dry deposition. Considering the spatial heterogeneity of mechanisms in influencing factors, tailored atmospheric pollution control measures are recommended to achieve targeted pollution mitigation.

The research progress of high background of soil heavy metals related to carbonate rocks was systematically reviewed from the aspects of spatial distribution, element combination, spatial coverage, controlling factors, formation process, and risk characteristics. At present, it was generally believed that the main causation for the formation of this type of high background was the “secondary enrichment” of elements in the weathering process of parent rock, that is, the leaching of major elements, e.g. Ca, caused the relative enrichment of trace elements, e.g. Cd. In this process, iron and manganese minerals played an important role in the in-situ concentration of these elements. From the geographical perspective, the hot and humid climate was conducive to the formation of a higher background content. In general, Cd and other elements in soil developed from carbonate eluvium had the character of “high background with low activity”, while in the alluvial areas formed by carbonate weathered materials, high acid soluble state of Cd might have occurred with risks of activation under conditions such as soil acidification. With high spatial variation of soil heavy metals in such areas, especially in the medium and small spatial scales, problems such as differentiation between natural background and anthropogenic pollution, quantitative recognition of relative risks, and development of control measures for environmental management, were required to be solved in the future study.

The determination of environmental background values for groundwater was recognized as a prerequisite and key step for the scientific identification, evaluation, and prevention of groundwater pollution. In this paper, the development history of groundwater environmental background value research was reviewed both domestically and internationally. Existing calculation methods for groundwater environmental background values were discussed along with their respective advantages and disadvantages. The research paradigm for background value reasonableness validation analysis and cause analysis was systematically summarized. Finally, existing problems in current groundwater environmental background value research were identified, and future development trends were projected. It was observed that inconsistencies in naming and definitions of groundwater environmental background values persisted among scholars worldwide. Although the influence of human activities on groundwater chemical components had been considered, quantitative determination of the "low human activity impact" threshold in conceptual frameworks remained challenging. Methods for determining environmental background values were generally categorized into mathematical-statistical approaches, model-based methodologies, and other alternative techniques. Each method was found to possess distinct advantages and limitations. The combination of hydrochemical analysis with mathematical statistics was demonstrated to emerge as one of the representative integrated approaches for calculating groundwater environmental background values, though methodologies for trace and micro-component analysis were noted to require further development. The reasonableness of environmental background values was typically assessed through comprehensive evaluation of multiple factors including surrounding pollution sources, hydrogeological conditions, lithological characteristics, land use patterns, pollution percentage indices, and stable isotope results. Regional geological settings and hydrogeological conditions were identified as primary controllers of groundwater environmental background values, while biogeochemical processes were determined to dominate micro-enrichment mechanisms. Based on established environmental background values, groundwater pollution levels were effectively evaluated, pollution risk areas were scientifically delineated, and reference thresholds were provided for environmental regulation and remediation targets. Future priorities were emphasized to include the urgent establishment of a global groundwater environmental background value database, enhanced application of existing background value data, and strategic utilization of big data analytics. These measures were proposed to optimize global groundwater resource protection and pollution control strategies under combined pressures of climate change and anthropogenic impacts.

Based on panel data of 284 cities at or above the prefecture level in China from 2012 to 2022, this paper studied the impact of new quality productivity on green innovation efficiency and the moderating effect of urbanization in this process by using fixed effect model, moderating effect model and general nesting spatial model. It was found that: (1) New quality productivity was confirmed to significantly enhance green innovation efficiency, a conclusion that still held after a series of robustness tests. (2) The promoting effect of new quality productivity on green innovation efficiency was most significant in the eastern region, followed by the central region, while no significant impact was observed in the western region. (3) Urbanization played a positive moderating role in the process of new quality productivity promoting green innovation efficiency. (4) New quality productivity was shown to generate positive spatial spillover effect that effectively improved green innovation efficiency of neighboring regions. Therefore, it was recommended to actively cultivate new quality productivity, optimize the innovation environment according to regional characteristics, vigorously promote the green urbanization process, and establish efficient regional cooperation mechanism to fully unleash the potential of new quality productivity and accelerate the green transformation of the economy and society.

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 SO₄^2- 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.

Under the synergistic advancement of global climate governance and China's "Dual Carbon" strategy, the development of forestry carbon sink systems urgently required breakthroughs in carbon quantification bottlenecks within seedling production. Edible raw material forests played an important role in improving the ecological environment and increasing economic growth, and estimating the carbon footprint of seedling production was crucial for assessing the carbon sink of forestry. By surveying existing star anise nursery operations for primary data in Guangxi, a new process-based life cycle inventory (LCI) dataset an 8cm×12cm star anise seedling of a typical edible raw material forest production system was created, covering three stages from seed collection to the transportation of seedlings to retailers. Incorporating the new LCI data into life cycle assessment (LCA) method, the total global warming (GW) impact of a star anise seedling was 0.145kgCO₂e, of which energy and materials consumption constituted 57.2% and 28.8% of total emissions. Electricity use is dominated by irrigation demands (75.9%) and water was estimated to be just over half of these emissions (60%). Among the production activities, the total environmental impact of the product was dominated by the irrigation at the field container seedling stage, which contributed 0.07kgCO₂e/seedling. In this case, the change in energy consumption had a notable impact on the carbon footprint, with a sensitivity of 0.804. Among them, the input of diesel had the largest impact on carbon footprint (42.4%). The results indicated that optimizing clean energy structures and implementing efficient water and nutrient management strategies could significantly reduce carbon emissions during seedling cultivation and offered practical guidance for advancing carbon labeling systems for edible forest products and supported forestry carbon neutrality progress.

To investigate the causes of ozone (O₃) pollution in the Pearl River Delta (PRD) region under non-high-temperature conditions, this study analyzed differences in O₃ pollution characteristics between high-temperature days (daily maximum temperature ³28°C) and non-high-temperature days (daily maximum temperature <28°C) using air quality and meteorological data from 2015 to 2023. The key findings are as follows: O₃ pollution in the PRD primarily occurred on high-temperature days, yet 17.2% of total polluted cities were observed during non-high-temperature days. High-temperature pollution was concentrated in central and southwestern PRD, while non-high-temperature pollution predominantly occurred in the southwest. Non-high-temperature O₃ pollution typically occurred under conditions of daily maximum temperature (25.0~27.2°C), relative humidity (44.9%~56.8%), and sunshine duration (7.7~9.8h). Compared to high-temperature pollution days, non-high-temperature pollution days exhibited 6.0% lower relative humidity and a more concentrated distribution of sunshine duration in higher intervals. The SHAP method demonstrated that relative humidity is the most influential meteorological factor affecting O₃ concentrations. On high-temperature days and non-high-temperature days, the contribution of relative humidity to the O₃_8h concentration can reach up to 30 and 60μg/m³, respectively. Low relative humidity (<65%) paired with prolonged sunshine duration synergistically promoted O₃ formation, whereas high relative humidity (>65%) combined with reduced sunshine suppressed it. Additionally, the pronounced impact of sunshine duration under non-high-temperature conditions highlights sufficient solar radiation as a prerequisite for O₃ generation. Under non-high-temperature conditions, NO₂ exerts a weaker influence on O₃ concentrations compared to high-temperature days, with its contribution to O₃ concentration variations quantified at approximately 15 μg/m³.

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.

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 SO₄^2- ) 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 SO₄^2- 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 SO₄^2- 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.

This study conducted a comprehensive life cycle assessment of the carbon footprint associated with the solidification/stabilization combined with barrier backfilling (SSB) technology through a typical heavy metal-contaminated site case in South China. Using the emission factor method and life cycle impact assessment approach, we quantified the environmental impacts across the entire remediation process. The results revealed that the SSB technology exhibited a carbon emission intensity of 0.190t CO2/m3 contaminated soil. The most important carbon emission unit processes were primary treatment (33.7%), site construction (32.7%), and barrier backfilling (31.9%). Material production emerged as the principal emission source, with concrete manufacturing contributing 51.9% and solidification/stabilization reagents accounting for 33.4% of total emissions. The comprehensive environmental impact score of this case reached 84.3kPt. The implementation process of risk control exerted the most significant human health impacts, which were primarily contributed by the formation of fine particulate matter during construction activities and the global warming potential.

This paper studied the characteristics and formation mechanisms of local photochemical pollution in Beijing during summer. Firstly, based on the meteorological observations, we obtained four typical meteorological clusters (M1~M4) based on the meteorological observations by using the K-means clustering algorithm and found the significant O₃ pollution difference among M1~M4. Then, under 2021 emissions of this city, we further simulated the local photochemical evolution of Beijing urban plumes respectively for four meteorological clusters, via a 0-D box model with the MCM (v3.3.1). The simulation results showed the daytime-averaged net O₃ production rate was 7.91×10^-9(M1), 7.58×10^-9(M2), 7.18×10^-9(M3), 3.55×10^-9(M4)·h^-1, but O₃ formation & loss pathways were very similar. O₃ formation was in the VOCs-limited regime, but its sensitivity to VOCs apparently decreased from M1 to M4. However, the simulated HCHO and CH₃ CHO had a little differences between various meteorological conditions, as well as their production rates and formation & loss pathways. The linear response of HCHO to VOCs indicated it could be as the good tracer for VOCs level. Finally, we calculated the O₃ increment reactivity (IR) of 65 VOCs species for each meteorological cluster, and found the differences in IR between low-reactivity and high-reactivity VOCs became significantly smaller under the M1 compared to M4, implying the importance of strengthening the control of low-reactivity components VOCs in on O₃ pollution days.

By integrating network toxicology, transcriptomics, and in vivo zebrafish assays, this study systematically investigated the differential toxicities and underlying molecular mechanisms of an alkyl phosphate (TiBP), a brominated phosphate (TDBPP), and a chlorinated phosphate (TCPP), with the aim of elucidating structure-dependent toxic effects of organophosphate flame retardants (OPFRs). The results showed that the halogens affected the accuracy and comprehensiveness of network toxicology predictions. Zebrafish experiments further confirmed that combining network toxicology with transcriptomic analysis provided a more comprehensive characterization of OPFR-induced toxic mechanisms. In terms of acute toxicity, TDBPP exhibited the lowest LC₅₀ (922.3μg/L), followed by TiBP (21.14mg/L) and TCPP (37.56mg/L). Mechanistically, the three compounds elicited toxicity through distinct gene-pathway networks. Owing to their halogen substituents, TDBPP and TCPP showed stronger metabolic and endocrine disruption, as evidenced by a 1.6-fold and 2-fold increase in lipid accumulation, respectively, compared with the control group under medium-dose exposure. In contrast, TiBP predominantly induced neuroimmune toxicity. At low doses, the non-halogenated structure of TiBP rendered zebrafish more sensitive to neuroconductive inhibition, resulting in the strongest inhibition of locomotor ability, with approximately 50% reductions in both swimming speed and distance. At high doses, the presence of chlorine atoms in TCPP enhanced receptor binding ability, resulting in predominant toxicity across the neural, metabolic, and immune systems. Although the brominated structure of TDBPP conferred the highest acute toxicity, its comprehensive effect at equitoxic doses was weaker than that of TCPP, potentially due to a delayed manifestation of metabolism-associated carcinogenicity. Overall, this study employed a multi-dimensional integrative strategy to elucidate how molecular structural features of OPFRs govern their biological effects.

To elucidate the potential ecological risks of carbon dots, a novel nanomaterial, this study investigated the physiological responses and underlying mechanisms of the freshwater microalgae Euglena gracilis following exposure to pristine carbon dots (CDs) and Cu-N-doped carbon dots (Cu-CDs). The results demonstrated that both types of carbon dots initially promoted but subsequently inhibited the growth of E.gracilis over time. Compared to CDs, Cu-CDs exerted a more pronounced impact on key physiological processes, including photosynthesis and antioxidant defense. Exposure to 1mg/L and 10mg/L Cu-CDs resulted in the accumulation of photosynthetic pigments and a decline in photosystem II activity, whereas a significant change in photosynthetic pigment content was observed only at 10mg/L in the CDs-exposed group. The maximum inhibition rates of superoxide dismutase activity induced by CDs and Cu-CDs were 62.52% and 78.35%, respectively. Metabolomics analysis further confirmed that Cu-CDs triggered a stronger metabolic disturbances, with the most notable alterations observed in lipid metabolism pathways, indicating compromised membrane stability of E.gracilis. Disruptions in amino acid and photosynthetic metabolism pathways were primarily attributed to oxidative stress. Additionally, both CDs and Cu-CDs affected energy metabolism by altering in alanine, aspartate, and glutamate metabolism, as well as glycolysis/gluconeogenesis pathways. Overall, the impairment of photosynthetic and antioxidant system may represent the primary toxic mechanisms of carbon dots in E.gracilis.

Taking Xingtai, a typical industrial city, as the study object, the pollution characteristics of O₃ were analyzed based on air quality monitoring and meteorological data from 2018 to 2022. The geographical detector method was employed to investigate the individual and combined impacts of meteorological factors and precursors on O₃ pollution. An air quality model was used to assess the sensitivity of O₃ generation, and EKMA curves were adopted to determine optimal emission reduction ratios in different control areas. The research revealed that the monthly average O₃ concentrations in Xingtai exhibited an inverted V-shaped pattern, with peak values observed in June (199.28μg/m³) and trough values recorded in January and December (37.16μg/m³). The hourly O₃ concentrations and their variation ranges across seasons followed the order: summer ＞ spring ＞ autumn ＞ winter. Significant seasonal differences were identified in the driving factors affecting surface O₃ concentrations. On an annual scale, meteorological factors were found to exert greater influence on O₃ pollution than precursor pollutants. Temperature and solar radiation were identified as the main positive driving factors for O₃ concentration increases, while humidity and precipitation served as primary negative drivers. CO and NO₂ were positive drivers in spring and summer but showed opposite effects in autumn and winter. The central urban area with surrounding counties, along with Qinghe and Linxi counties, were classified as VOCs control areas. The northwestern and central-eastern counties were designated as synergistic control areas for both VOCs and NO_x. The optimal emission reduction ratios for between VOCs and NO_x were determined to be 1.5:1and 1:1, respectively, in the different control areas.

This study employed a partial denitrification-Anammox biofilm system (PDA-Bf) to treat simulated municipal wastewater, with a focus on exploring its nitrogen removal performance under mesophilic conditions (34℃). After 317 days of operation, the results indicated that under an influent carbon-to-nitrogen ratio (C/N) of 2.1, the total nitrogen (TN) concentration in the effluent was reduced to 10.94mg/L, with an average TN removal rate of 82.6%. Moreover, the contribution of the Anammox pathway to TN removal significantly increased over time. The study found that the abundances of the denitrifying genus Thauera and the anammox genus Candidatus Brocadia in the biofilm significantly increased with operation time. Thauera increased from 0.37% on day 250 to 4.11% on day 305, and Ca. Brocadia rose from 0.27% to 3.51%. The two genera worked well in synergy. The outer layer of the biofilm had a high abundance of genes encoding nitrate reduction, such as narG (55152hits), narH (35866hits), and narI (16506hits), indicating that this area was suitable for the growth of denitrifying bacteria and provided nitrite for the Anammox reaction. In contrast, the inner layer of the biofilm had a higher abundance of the Anammox-related hdh gene (1174hits), and lower abundances of nitrite reduction genes nirK (13400hits) and nirS (3954hits), maintaining a higher nitrite concentration and creating a suitable environment for Anammox bacteria (AnAOB). This stratified microbial community structure suggests that the outer and inner layers of the biofilm are respectively suitable for the growth of Thauera and Ca. Brocadia, jointly promoting the efficient nitrogen removal performance of the system.

This study applied the IPCC methodology to estimate carbon emissions in Shanxi Province from 2010 to 2022. A Kaya-LMDI model was employed to identify the key drivers influencing carbon emissions in the region. Using 2022 as the baseline year, the LEAP-Shanxi model was developed to forecast carbon emissions from 2023 to 2060. Economic development acted as the primary driver of carbon emission growth, whereas energy intensity emerged as the dominant restraining factor; By 2060, under four specific scenarios—industrial energy efficiency improvement, low-carbon transportation transition, accelerated new energy adoption, and optimized power structure—energy conservation and carbon reduction effects would become particularly pronounced, these measures could reduce sectoral emissions by 42.16, 3.21, 1.38 and 31.73Mt respectively; Both baseline and integrated scenarios indicate that Shanxi Province could reach its carbon peak by 2030, with projected emissions of 764.33 and 742.34Mt respectively; The comprehensive scenario demonstrates a potential reduction of 107.42Mt in carbon emissions compared to the baseline projections for 2060. These findings can offer a robust theoretical foundation for Shanxi Province to develop targeted low-carbon strategies and implement effective emission reduction measures.

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.

This study utilized natural red clay (RC) and 700℃ 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.

This study analyzed the carbon reduction effect of national green data centers on cities and its mechanism. Then, based on the pilot and construction work of national green data centers, a quasi-natural experiment was constructed. Using the difference-in- differences method and panel data of 283 cities from 2011 to 2022, the carbon reduction effect of national green data centers was empirically analyzed, and its mechanism and heterogeneity were explored. The pilot of national green data centers has a significant carbon reduction effect, with a coefficient of -0.013, which is significant at the 5% statistical level. The pilot of national green data centers significantly reduces the carbon emission intensity of cities. This result remains valid after multiple robustness tests, including parallel trend tests, placebo tests, exclusion of selection bias, exclusion of the impact of other policies, and exclusion of the impact of the epidemic. The pilot of national green data centers can reduce the carbon emission intensity of cities by promoting the development level of the digital industry and the green technological innovation level of the region. The impact of the pilot of national green data centers on the development level of the digital industry and the green technological innovation level is significantly positive at the 1% statistical level, with coefficients of 0.039 and 0.061, respectively. The carbon reduction effect of national green data centers is more significant in non-energy-rich cities, cities with high environmental protection levels, and cities with high information levels. The impact of the pilot of national green data centers on these three types of cities is significantly at least at the 10% statistical level, with coefficients of -0.016, -0.017, and -0.016, respectively. Therefore, efforts should be made to promote the green transformation of data centers and expand the scope of the pilot of national green data centers.

Poyang Lake is characterized by significant water level fluctuations, leading to complex transformation processes among precipitation, soil water, and groundwater. Due to the limitations of intricate wetland conditions and traditional monitoring methods, it is challenging to conduct quantitative studies on soil water movement and its interaction with groundwater. In this study, three vegetation communities at different elevations in Poyang Lake were investigated to analyze the isotopic composition of precipitation, lake water, groundwater, and soil water (0~80cm). The characteristics of wetland soil water movement were examined across various hydrological periods. The results showed that the slope of the soil evaporation line (SEL) in the Artemisia capillaris community (5.91) was significantly lower than that of the local meteoric water line (LMWL, 7.60). The lc-excess values of soil water in 0~60cm layer were negative, indicating strong evaporation, with a maximum impact depth of 60 cm. The slopes of the SEL in the Phragmites australis and Carex cinerascens communities (6.70 and 6.75, respectively) were slightly lower than the LMWL, and the lc-excess values of soil water were close to 0, indicating minimal evaporation. Regarding soil water movement, the δ¹⁸O values of soil water in the A. capillaris community increased with depth during spring (May) and summer (June to August), indicating piston-flow dominated transport. During autumn (September and October), soil water δ¹⁸O values became enriched and decreased with depth, indicating the dominant influence of evaporation. Furthermore, the soil water δ¹⁸O values in the A. capillaria community were significantly enriched compared to groundwater isotopes. No depleted isotope signals or evidence of groundwater supply were detected in the soil water, even when the groundwater table was at its shallowest (1.92m). These results suggest that vertical hydrological connectivity between root-zone soil water and groundwater was blocked. In contrast, soil water movement in the P. australis and C. cinerascens communities was significantly influenced by groundwater level fluctuations. During the groundwater level rise period (April and May), shallow soil water (0~40cm) in these two communities primarily originated from atmospheric precipitation, while deep soil water (40~80cm) was replenished by capillary rise of groundwater. Groundwater contributed more than 50% to the replenishment of root-zone soil water. During the shallow groundwater table period (June and August), frequent exchanges occurred between soil water and groundwater in the P. australis community. In the groundwater table decline period (September and October), the P. australis and C. cinerascens communities exhibited non-uniform soil water flow processes, characterized by noticeable preferential flow.

Based on panel data from 30 provinces in China from 2011 to 2021, this paper uses the coupling coordination degree model, local spatial autocorrelation analysis, and system GMM regression method to systematically examine the spatiotemporal evolution characteristics and influencing factors of the coupling coordination level between China's new quality productivity and carbon emissions. The study found that the annual average of the new quality productivity index increased from 0.1 to 0.23, and the carbon emission intensity decreased from 2.548 to 1.942, indicating a continuous improvement in the synergy level between the two. The coupling coordination degree shows a gradient differentiation of "high in the southeast and low in the northwest". Eastern coastal provinces have risen to high-quality coordination based on digital economy and green technology innovation, while northern energy bases have long been in low value agglomeration due to the "high carbon low efficiency" path dependence. Economic development, opening up to the outside world, and innovation levels significantly promote the improvement of coordination, while environmental regulations have a restraining effect due to the "compliance cost squeeze". Regional heterogeneity analysis shows that the eastern region strengthens technology spillover through global value chain embedding, the northeast is constrained by structural contradictions in heavy industry, and the western region suppresses innovation diffusion due to geographical decline and lagging infrastructure.

Based on the high-density observation network of low-cost CO₂ analyzers deployed in Hangzhou, an analysis of CO₂ concentration spanning a complete one-year from April 2023 to March 2024 was conducted. The results showed that: (1) Under field observation conditions, low-cost instruments experience data gaps, with annual data collection rates at various stations ranging from 38.58% to 99.39%. The Mean Bias Error (MBE) for the two non-dispersive infrared (NDIR) instruments is (3.2 ±1.4) μmol/mol. Therefore, it is essential to enhance the data collection rate at stations when deploying high-density network. (2) Observation from NDIR-based low-cost instruments were highly sensitive to environmental variations, but could be effectively corrected by machine learning-based calibration schemes. After correction, the correlation coefficient R² between the network data and high-precision observation improved from 0.33 to 0.77, with the MBE of 1.2μmol/mol. (3) The high-density network of low-cost CO₂ analyzers was can effectively capture the spatio-temporal variability of CO₂ concentration. Diurnal variations and spatial distributions across stations reflected seasonal variations characteristics of urban CO₂ sources and sinks. The deployment of this network has demonstrated the feasibility of operating a low-cost, high-density monitoring system in cities with complex underlying surfaces, such as those in China. This approach provided a basis for estimating urban carbon emissions and evaluating the effectiveness of emission reduction measures.

To investigate the variation rules, pollution characteristics, and their regional transport of fine particulate matter (PM_2.5) components in different seasons from Hohhot and Wuhai cities. In this study, the concentration of PM_2.5 and its chemical components, such as water-soluble ions, organic carbon (OC), elemental carbon (EC), and metallic elements, and meteorological data, were obtained from the atmospheric super station in June-August and December of 2022, and January-February of 2023 from Hohhot and Wuhai. The sources and transport paths were also analyzed according to the Positive Definite Matrix Factor Decomposition (PMF) model and the Backward Trajectory (HYSPLIT) model. PM_2.5 mass concentration in winter was higher than that in summer in both cities. PM_2.5 mass concentration in Wuhai was higher than that in Hohhot in the same season. PM_2.5 in both cities is alkaline in winter and summer. The alkalinity of PM_2.5 in Hohhot was stronger than that in Wuhai during summer, and weaker than that in Wuhai during winter. The content of K, Mn, Cu, Ba, Ti, K⁺, and Cl^- in PM_2.5 in winter was higher than that in summer in the two cities. The two cities were more affected by biomass combustion, coal-fired emissions, and motor vehicle emissions in winter. PM_2.5 in Hohhot during summer mainly came from combustion sources, secondary inorganic sources, industrial sources, soil dust sources, and mixed sources motor of vehicle and road dust, while in winter it mainly came from coal combustion sources, biomass combustion sources, secondary inorganic sources, soil dust sources, mixed sources of motor vehicle and road dust, and mechanical wear sources. PM_2.5 in Wuhai during summer mainly came from combustion sources, secondary inorganic sources, industrial sources, soil dust sources, motor vehicle sources, road dust sources, while in winter it mainly came from combustion sources, secondary inorganic sources, industrial sources, soil dust sources, mixed sources of motor vehicle and road dust, and mechanical wear sources. Hohhot city was dominated by secondary sources in both summer and winter. Wuhai city was dominated by the mixture of motor vehicle and road dust in summer, while by secondary inorganic sources in winter. Hohhot City was mainly affected by air currents from southern Shanxi Province, northern Shaanxi Province, and southern Mongolia in summer, with potential source areas being southern Shanxi Province, southern Hebei Province, and northern Henan Province. Wuhai was mainly affected by air currents from eastern Xinjiang, Alxa League, southern Shaanxi Province, and Bayannur City in summer. Hohhot and Wuhai were affected by air currents from Alxa League and southern Mongolia in winter, with the difference that PM_2.5 transport in Wuhai in winter was also affected by air currents from northern Xinjiang. The potential source areas for winter in Hohhot are local, Baotou., Bayannur, Ordos, northeastern Alashan League, and the southern region of Mongolia, while that in Wuhai City during summer and winter were the eastern part of Xinjiang, Hexi Corridor region, Alashan League, Ordos City, Ulanqab City, and Wuhai City. The research results provide data support for the prevention and control of air pollution in typical cities along the Yellow River Basin.

This study focuses on five typical lakes in cold-arid areas, analyzing the phosphorus pool capacity and phosphorus migration dynamics of sediments using methods such as phosphorus fractionation, diffusive gradients in thin films (DGT), and the DGT Induced Fluxes in Sediments model (DIFS). Partial least squares path modeling (PLS-PM) was further employed to identify the key driving factors for the endogenous phosphorus pool capacity and migration dynamics in these lakes. The results showed that the average values of total phosphorus (TP_w), total nitrogen (TN_w), and nitrogen-to-phosphorus ratio (TN_w/TP_w) in the water of the five lakes were (0.81 ±1.31)mg/L, (3.40 ±1.87)mg/L, and (26.13 ±22.75), respectively, indicating that these were phosphorus-limited lakes. The average total phosphorus (TP_s) content in surface sediments was (763.48 ±563.70)mg/kg, with calcium-bound phosphorus (Ca-P) accounting for 51.09% of the TP_s. The comprehensive pollution index (FF) values for sediments indicate a severe pollution level. The biologically available phosphorus (BAP) dissolved active phosphorus (C_DGT-P), and distribution coefficient (K_d) average (193.54 ±55.94)mg/kg, (0.19 ±0.14)mg/L, and (11.34 ±9.29)cm³/g, respectively. All three indicators of phosphorus pool capacity were lower than those in lakes of the eastern plains, reflecting a relatively low phosphorus reservoir capacity in cold and arid lakes. The DIFS model shows that the reaction time (T_c) of the five lakes ranges from 0.004 to 74, 170s, lower than that of lakes in the eastern plains, indicating slower phosphorus migration dynamics and a relatively lower supply rate to the water body. PLS-PM analysis reveals that the primary factor influencing phosphorus reservoir capacity in these lakes was sediment properties (0.64, P<0.05). The main factor influencing phosphorus migration dynamics (0.95, P<0.05) was the environmental conditions of the water bodies, with limited influence from lake trophic state and phytoplankton.