Huanjing Kexue/Environmental Science最新文献

Acid mine drainage （AMD） is of great concern owing to its safety hazards and environmental risks. However, little is known about the effects of AMD leakage on soil physicochemical properties and bacterial communities in ecologically fragile desert steppe soils, especially in the soil profile. Therefore, an AMD-contaminated profile and clean profile were used as research objects respectively to investigate the effects of AMD on soil physicochemical properties and bacterial community composition, structure, and interactions in soil layers at different depths of desert grassland and, based on this, to analyze the driving factors of bacterial community changes. The results showed that AMD significantly decreased the pH and increased electrical conductivity （EC） and heavy metal content in the upper （0-40 cm） soil layer of the profile. The AMD-contaminated profile bacteria were dominated by Proteobacteria, Firmicutes, and Actinobacterota, whereas clean profile bacteria were dominated by Firmicutes and Bacteroidota, with Thermithiobacillus and Alloprevotella being the biomarkers for the contaminated and clean profiles, respectively. AMD contamination significantly reduced bacterial diversity and significantly altered bacterial community structure in the upper soil layers of the profile. The results of redundancy analysis showed that soil physicochemical properties explained 57.21% of the variation in bacterial community changes, with EC, TP, TN, As, Zn, and Pb being the main drivers of bacterial community changes. Network analyses showed that AMD contamination increased profile complexity, modularity, and intra-community competition, thereby improving bacterial community stability and resilience. In conclusion, the study provided useful information on the effects of AMD pollution on soil physicochemical properties and bacterial communities in desert steppe soils, which may help to improve the understanding of the ecological hazards of AMD pollution on soils in extreme habitats.

Under the "dual-carbon" strategic goals, it is urgent to examine whether the energy consumption permit trading scheme （ECPTS）, as an innovative system in China's market-oriented reform of the energy sector, can promote the synergistic enhancement of pollution reduction and carbon abatement. Based on provincial panel data of China from 2008 to 2019, this study adopted a difference-in-differences model to examine the impacts of the ECPTS on the synergistic enhancement of pollution reduction and carbon abatement. The results demonstrated that the ECPTS improved the level of pollution reduction and carbon abatement in pilot areas. Specifically, the ECPTS led to a reduction of 13.3% in CO₂ emissions and 3.1% in PM_2.5 concentration in the pilot areas and resulted in an overall improvement of pollution reduction and carbon abatement by 0.237 units. Mechanism analysis revealed that energy efficiency served as a pathway through which the ECPTS empowered the synergistic enhancement of pollution reduction and carbon abatement. Moreover, the strengthening of local government environmental protection goals enhanced the pollution reduction and carbon abatement effects of the ECPTS. Surprisingly, the effectiveness of the ECPTS was not undermined by the goal of economic growth. This study provides new empirical evidence for understanding the relationship between market-based environmental regulation and collaborative governance and provides strong support for China to achieve its "dual-carbon" strategic goals.

Dissolved carbon in groundwater plays an important role in carbon cycling and ecological function maintenance, and its concentration level affects the migration and transformation of pollutants in groundwater. To understand the spatiotemporal variation characteristics of dissolved carbon and its driving factors in shallow groundwater around plateau lakes, variations in the concentrations of dissolved organic carbon （DOC）, inorganic carbon （DIC）, and total carbon （DTC） and their driving factors in shallow groundwater （n = 404） around eight plateau lakes were analyzed. The results indicated that the average values of ρ（DOC）, ρ（DIC）, and ρ（DTC） in shallow groundwater around plateau lakes were 8.23, 49.01, and 57.84 mg·L^-1, respectively, with the ρ（DOC） in 79.0% of shallow groundwater samples exceeding 5 mg·L^-1. There were no significant differences in the DOC, DIC, and DTC concentrations between rainy and dry seasons, whereas the change in dissolved carbon concentrations in shallow groundwater were strongly affected by the intensity of agricultural intensification and the depth of groundwater table； the DOC, DIC, and DTC concentrations in shallow groundwater from facility agricultural regions （SFAR）, cropland fallow agricultural regions （CFAR）, and intensive agricultural regions with deeper groundwater tables （DIAR） were significantly reduced by 25.8% - 56.6%, 14.0% - 32.9%, and 16.6% - 36.7%, respectively, compared with those in intensive agricultural regions with shallower groundwater tables （SIAR）. Additionally, the dissolved carbon concentrations in shallow groundwater from DIAR were significantly lower than those of SFAR and CFAR. RDA revealed that physicochemical factors in water and soil significantly explained the changes in the dissolved carbon concentrations. Moreover, the dissolved carbon concentrations in shallow groundwater around Yilong Lake were significantly higher than those of other lakes, whereas that of Chenghai Lake was significantly lower than that of other lakes. Our study highlights that agricultural intensification intensity and groundwater table depth jointly drove the variations in dissolved carbon concentrations in shallow groundwater around plateau lakes. The study results are expected to provide a scientific basis for understanding the carbon cycle in plateau lake areas with underground runoff flowing into lakes and evaluating the attenuation of pollutants by dissolved carbon in shallow groundwater.

Volatile organic compounds （VOCs） from the wooden furniture-manufacturing industry are an important emission source. To study the emission characteristics of VOCs from the wooden furniture-manufacturing industry and associated environmental impacts, nine typical wooden furniture manufacturers in China were selected to carry out sample collection and VOCs detection. The maximum incremental reactivity （MIR） method and secondary organic aerosol （SOA） formation potential method were used to quantify the corresponding contributions to the generation of O₃ and SOA. The results showed that： ① The concentrations of VOCs emitted from different types of coating exhaust gas were different. The emission concentration of VOCs in solvent-based coating exhaust gas was significantly higher than that in water-based coating exhaust gas and ultra-violet （UV） coating exhaust gas, and the VOCs emission concentrations ranged between 2.82 - 155.37, 1.13 - 104.45, and 0.57 - 1.15 mg·m^-3, respectively. ② The main organic group in solvent-based coating exhaust gas was esters, accounting for 45.88%, and butyl acetate （31.07%） was the main VOCs species. The main organic group in water-based coating exhaust gas and UV coating exhaust gas was alcohols, and the main VOCs species in water-based coating exhaust gas and UV coating exhaust gas were both ethanol, accounting for 46.63% and 34.32%, respectively. ③ The OFP of VOCs emitted by solvent-based coating, water-based coating, and UV coating were 149.23, 50.90, and 1.87 mg·m^-3, respectively, and the primary contributing components of OFP of different types of coating were m/p-xylene （26.61%）, ethanol （36.35%）, and ethanol （23.98%）, respectively. ④ The SOA of VOCs emitted by solvent-based coating, water-based coating, and UV coating were 0.76, 0.25, and 0.01 mg·m^-3, respectively. The SOA generation of various types of coating was dominated by aromatics（96.35%-98.96%）, and the main active compounds were toluene, ethylbenzene, and xylene. ⑤ Comparing the environmental impact of exhaust gas from solvent-based coating, water-based coating, and UV coating, it was found that the OFP and SOA generated by the VOCs emitted from solvent-based coating were much higher than those for water-based coating and UV coating. Therefore, the implementation of water-based coating and UV coating substitution strategy from the source could effectively reduce VOCs emissions and abate OFP and SOA productions.

To elucidate the characteristics of VOCs chemical components during heavy pollution episodes, hourly online VOCs data derived from 11 heavy pollution events in Tianjin from 2019 to 2020 were employed. The positive matrix factorization （PMF） and conditional bivariate probability function （CBPF） were employed to analyze the sources of VOCs during heavy pollution episodes. The results indicated that the average VOCs volume fraction during these episodes was recorded at 35.7×10^-9. Furthermore, it was observed that during the winter emergency response period, there was a discernible increase in the volume fraction of VOCs when compared to that during the autumn season. Specifically, there was a notable upswing of 48% in the olefins category, whereas alkanes registered a 4% increase. Additionally, the VOCs component structure changed significantly during the heavy pollution episodes. During the orange warning period, the proportion of alkanes increased by 36%, and the proportion of acetylene decreased by 32%. During the yellow warning period, the proportion of alkanes increased by 14%, and the proportion of acetylene decreased by 5%. During the emergency response period, motor vehicle emission sources, natural gas evaporative sources, and solvent use sources were the main contributors of VOCs in environmental receptors, contributing 17.5%, 15.4%, and 15.2%, respectively. Compared with that during the period antecedent to the emergency response, the contribution of vehicle emission sources and diesel volatile sources to VOCs in environmental receptors decreased by 2.0% to 5.5% and 2.1% to 6.6%, respectively, and the contribution of solvent use sources decreased by 0.2% to 2.4% during the yellow warning period. During the orange warning period, the contribution of motor vehicle emission sources was reduced by 0.1% to 8.3%, and the contribution of solvent use sources was reduced by 0.5% to 6.2%.

To deepen the recognition of changes in industrial water use with socio-economic development, a "double-layer nested" structural decomposition analysis has been proposed to decompose the influence of the drivers of industrial water use change by sectors in China from 2002 to 2020. The results showed that the scale expansion factors represented by consumption, investment, and export were the main factors for the growth of industrial water use in different sectors, among which the expansion effect of per capita consumption grew faster. Additionally, there were obvious differences in the major drivers of industrial scale expansion between different sectors, which directly drove the industrial structure change. The production process water use effect and water reuse effect were the main factors to curb the growth of industrial water use. The accumulation of both had completely offset the positive effect of industrial scale expansion during the period, reducing industrial water consumption by 11.2 billion m3. However, the production process water use changes in metal extraction, smelting, and processing and energy processing sectors such as electric power had a smaller negative effect, leading to the potential for improving industrial water efficiency solely through a relatively small improvement in water resource reuse. Therefore, it is necessary to strengthen industrial water conservation management based on the differences in the impact of various sectors to promote the transformation and upgradation of industrial production and consumption structures, and to avoid another increase in industrial water use in China.

To understand the karst groundwater hydrochemical characteristics and ion sources of the Jinan Baotu Spring area, this study focused on the three functional zones as an indirect recharge area, direct recharge area, and discharge area. Through water sample collection and testing, the spatial variability of groundwater chemical characteristics in different functional zones and the formation mechanism were analyzed using hydrochemistry parameter statistics, multivariate statistics, self-organizing map, hydrochemistry graphical analysis, ion ratios, and other methods, guided by the theory of groundwater flow system and combined with regional physical geography and hydrogeological conditions. The results showed that： the groundwater of each functional zone was alkaline as is typical in the dissolution of carbonate minerals. Owing to the different groundwater runoff pathways, the variability of water chemistry parameters in different functional areas was obvious. The groundwater of the discharge area was recharged by both the direct recharge area and the indirect recharge area. The hydrochemistry type changed from HCO₃-Ca type to HCO₃·SO₄-Ca type through the indirect recharge area to the discharge area. The presence of a small amount of gypsum dissolution within the aquifer generated Ca²⁺ and SO₄^2-. The ions in groundwater mainly came from the dissolution and filtration of aquifer rock minerals, and at the same time, they were affected by cation exchange, mineral dissolution equilibrium, and the combined effects of human activities. The groundwater in the Baotu Spring area was greatly influenced by human activities, which to some extent affected the evolution of groundwater hydrochemistry in the spring area.

The Bohai Rim Plain is an important grain-producing area in China. The cultivated land resources have great potential for production, but there are many influencing factors. Understanding the spatiotemporal change characteristics and driving factors of the net primary productivity （NPP） of cultivated land vegetation in this region is of great significance to improve the regional cultivated land production conditions, excavate and enhance the production capacity of cultivated land, and ensure national food security. In this study, Theil-Sen Median trend analysis, Mann-Kendall significance test, Hurst index, and other methods were used to explore the spatiotemporal change characteristics, stability, and sustainability of regional cultivated land NPP. The influence of driving factors on the spatial heterogeneity of cultivated land NPP was analyzed by using optical parameters-based geographical detectors. The results showed that： ① From 2001 to 2019, due to the expansion of construction land during industrialization and urbanization, the cumulative decrease in the area of cultivated land in the Shandong area around the Bohai Sea was 2 004.51 km². ② During the selected research period, the interannual variation of average cultivated land NPP showed a fluctuating and increasing trend. In terms of spatial distribution, the NPP of cultivated land was bounded by the Dongying District, with the spatial heterogeneity in the north being significantly lower than that in the south. ③ The area with increasing NPP of cultivated land accounted for 88.06% of the total area of cultivated land, mainly with low and medium fluctuations. The NPP of cultivated land will maintain an overall sustained trend of increase across the region in the future. ④ The average annual relative humidity study area had the strongest explanatory power for the spatial variability of NPP in cropland, with a q-value of 0.26, followed by surface soil salinity and subsoil salinity, with q-values greater than 0.2. The interactions between the different drivers all showed either nonlinear enhancement or bifactorial enhancement. The results of this study will help to reveal the characteristics of the changes in cultivated land production capacity and its driving forces in the Bohai Sea region and also provide a theoretical basis for the ecological protection and sustainable development of the region.

Based on the observation data of O₃ concentration in Yinchuan in 2022, the monthly variation characteristics of O₃ concentrations were analyzed. Further, based on the observation data of meteorological elements, conventional pollutants, and volatile organic compounds （VOCs） concentrations at an urban site in Yinchuan from May to July, the difference in meteorological elements and precursor concentrations between the polluted days and the non-polluted days were compared. Then, the O₃ sensitivity and the VOCs sources were discussed using the Framework for 0-D Atmospheric Modeling （F0AM） and positive matrix factorization （PMF） model, respectively. The results showed that： ① The O₃ pollution occurred from May to July in 2022, and the concentrations of O₃-8h_-90per were 156 μg·m^-3, 170 μg·m^-3, and 174 μg·m^-3, respectively, with exceeding standard rates of 9.7%, 26.7%, and 29.0%, respectively. ② Compared with those on the non-polluted days, the hourly mean values of temperature, total solar radiation, and concentrations of various precursors on the O₃-polluted days increased, including the volume concentrations of propane, isobutane, ethane, n-butane, and dichloromethane, which increased significantly by 33.1%, 29.1%, 25.0%, 22.7%, and 21.3%, respectively. The results showed that the combined increase in pollutant emissions and adverse meteorological conditions contributed to the formation of O₃. ③ From May to July 2022, the top five VOCs species in terms of ozone formation potential （OFP） value on whole, non-polluted, and polluted days were the same. They were acetaldehyde, m/p-xylene, ethylene, isoprene, and toluene, mainly from solvent use sources, natural sources, and chemical industry emissions. ④ The local O₃ production was mostly controlled by VOCs, and the relative incremental reactivity （RIR） results revealed that O₃ production showed strong positive sensitivity to alkene and aromatic hydrocarbon but showed negative sensitivity to NO_x on both polluted and non-polluted days. The relative contributions of active species such as acetone, ethylene, and isobutane to O₃ production were high, and the implementation of an emission reduction scheme with the ratio of VOCs to NO_x emission reduction much greater than 1 could effectively reduce the local O₃ concentration. ⑤ The main sources of atmospheric VOCs in Yinchuan were motor vehicle emission sources （32.3%）, process sources （20.7%）, combustion sources （19.2%）, solvent use sources （12.7%）, gasoline volatile sources （9.1%）, and natural sources （6%）, and the contribution rate of motor vehicle emission sources on polluted days increased by 4.6% compared with that on non-polluted days, indicating that the motor vehicle emission source was an important object of summer VOCs control

Clarifying the regional transmission and local generation contributions of ozone （O₃） is important for controlling O₃ pollution. To quantify the regional background and spatial-temporal variations of O₃, a comprehensive study was conducted using multiple methods including principal component analysis （PCA） and TCEQ, with Henan Province as a case study. Based on monitoring data from 59 national sites in Henan Province during 2019-2021, four methods were employed to estimate the regional background of O₃. Method 1 was the traditional method, performing O₃ univariate-multisite PCA analysis. Method 2 was a multivariate-single-site PCA analysis considering nitrogen dioxide and meteorological conditions as constraints. Method 3 combined PCA and multiple linear regression （MLR） to determine regional background contributions, drawing on the idea of source apportionment. Method 4 was the TCEQ method that used the lowest measured O₃-8h concentration as the regional background. The estimation results showed that Methods 1 and 2 were basically equal, and Methods 3 and 4 were approximately 37-60 μg·m^-3 lower than Method 1. From 2019 to 2021, the changes in regional background ρ（O₃-8h） estimated by Methods 1-4 were 1.6, -13.4, 5.9, and -3.5 μg·m^-3, respectively. The average estimations derived from multiple methods showed that the regional background ρ（O₃-8h） in Henan Province from 2019 to 2021 concentrations were 82.0, 79.0, and 79.7 μg·m^-3, accounting for 75.9%, 76.4%, and 78.7% of the total regional O₃-8h, respectively. The regional background O₃-8h estimated by the four methods showed obvious seasonal changes, characterized by summer > spring > fall > winter.