Journal of Environmental Management最新文献

The changes in the carbon emissions in China's provincial construction industries are of high complexity. It is essential to understand the changes in the construction carbon emissions (CCEs) in China on the provincial scale. This study evaluates the factors and structural paths of the changes in provincial CCEs in China between 2012 and 2017 using the structural path decomposition analysis. The results show that the emission intensity effect and production structure effect contributed greatly to the reduction of CCEs across various regions, while the final demand effect had contrary impacts. The local nonmetallic mineral products industry (c13), metal smelting and pressing industry (c14), and electricity industry (c24) generally contributed significantly to the emission intensity effect, production structure effect, and final demand effect across most regions. The consumption of local c13, c14, and c24 by the construction industry (c27), namely "local c13→c27", "local c14→c27", and "local c24→c27" were generally the important structural paths of the CCEs changes across various regions. Nonlocal industries such as Hebei c14 and nonlocal structural paths such as "Hebei c14→c27" contributed substantially to the CCEs changes in many regions such as Beijing. The emission intensity effect, first-order production structure effect, and final demand effect typically dominated the effects of the critical structural paths of the CCEs changes across various regions. This study can help policymakers better understand the changes in China's provincial CCEs to formulate region-specific emission reduction measures and provide a comprehensive reference for related research.

The ecological environment, resource endowment, and the level of socioeconomic development vary extensively amongst regions in the Yellow River Basin (YRB). To ensure the basin's sustainable development, the supply and demand relationship of ecosystem services (ESs) within the basin was analysed from the perspective of three subsystems: flood-sediment transport, socioeconomics, and ecological environment. The supply, demand, and the ratio of supply to demand of typical ESs were initially computed for 385 counties and districts within the YRB. These ESs included soil retention (SR), flood mitigation (FM), water yield (WY), crop supply (CrS), carbon sequestration (CS), and natural accessibility (NA). Correlations among ecosystem service supply-demand ratios (ESDRs) were completed and the spatial characteristics of the weighted multiple ESs supply-demand index (WMESI) were then investigated. Finally, the importance of WMESI driving factors were explored using extreme gradient boosting. Calculated for three subsystems in 385 counties and districts, the coupling coordination degree (CCD) indicated that: (i) ESDRs exhibit spatiotemporal heterogeneity, with FM and WY having relatively lower ESDRs; (ii) the trade-off and synergy relationships among ESDRs vary in a dynamic manner. In particular, a disruptive change in the relationship between the ESDR of SR and other ESDRs occurred in 2010; (iii) in the basin's downstream region, WMESI exhibits low-low clustering, with both population and precipitation having a significant impact on WMESI. Moreover, precipitation factors shifted significantly towards population factors; (iv) Overall, the CCD of 385 counties and districts in the YRB is low, and the spatial imbalance of CCD was mainly attributable to socioeconomic factors. The present research findings provide new insights into the sustainable governance of the YRB.

Recent research has reported the strong herbicidal activity of Artemisia argyi leaf powder (AALP), indicating its high potential for use as an environmentally friendly weed management solution for ecological agriculture. However, AALP's impacts on soil physicochemical properties and microbial communities have remained uninvestigated. This study explores these effects through pot experiments assessing the AALP's efficacy in weed suppression and its ability to promote the growth of Pinellia ternata, a plant utilized in traditional Chinese medicine. The results demonstrate that a 10% concentration of AALP suppressed nearly 100% of all weeds. Additionally, AALP treatments at 2.5%, 5%, 7.5%, and 10% concentrations increased P. ternata yields by 29.79%, 24.76%, 35.67%, and 31.00%, respectively. A soil analysis revealed that AALP enhanced soil fertility by increasing the contents of nutrients such as SOM, AN, AP, AK, Ca, Fe, Mn, and Zn, as well as the enzyme activity of CAT, ACP, UE, and SC, creating an optimal growth environment for P. ternata. In addition, AALP significantly increased the PA (phenolic acid) content in soil, which is a key factor in inhibiting weed germination and growth. Furthermore, a microbial community structure analysis indicated an enrichment of Actinobacteriota and Bacteroidota after AALP treatment, with notable increases in the growth-promoting bacteria Sphingobium and Flavobacterium. A permutational multivariate analysis of variance (PERMANOVA) based on the Bray-Curtis distance reaveled that all of the tested soil properties were significantly correlated with changes in bacterial community composition except for pH. Further two-factor correlation network analysis identified AN, Zn, SC, and PA as key environmental factors. Finally, the Sphingobium sp. strain AFR15, isolated from AALP-treated soil, exhibited significant growth-promoting effects on P. ternata. After inoculation with Sphingobium sp. strain AFR15 for one month, the heights of P. ternata were increased significantly. The leaf length and leaf width of P. ternata were also positively correlated with the treatment concentration of AFR15, and the chlorophyll contents of the leaves also increased. This results highlighted Sphingobium sp. strain AFR15's potential as a specialized microbial fertilizer in crop yield increased. In conclusion, AALP applications not only control weeds but also promote P. ternata growth by improving soil physiochemical properties and fostering beneficial bacterial allies. These findings lay the groundwork for future research and promote the use of AALP in ecological agriculture.

Water pollution control in transboundary watersheds can improve the water environment quality, alleviate water resource conflicts, and is an important guarantee for achieving healthy and stable development of watersheds. Ecological compensation is an important measure to solve the problem of water pollution in transboundary watersheds and has been widely applied in China. We constructed differential game models for water pollution control in transboundary watersheds under four scenarios: (1) no ecological compensation scenario, (2) upstream one-way ecological compensation scenario, (3) downstream one-way ecological compensation scenario, and (4) upstream and downstream two-way ecological compensation scenario. We studied the optimal water pollution control strategies and ecological compensation strategies under different scenarios, and compared the results obtained under different scenarios to explore which scenario has better water pollution control and ecological compensation, as well as the applicable conditions for different one-way ecological compensation. The results indicate that both upstream and downstream one-way ecological compensation can promote water pollution control, and the optimal one-way ecological compensation should be determined based on the cost and benefit parameters of upstream and downstream water pollution control. The upstream and downstream two-way ecological compensation can reduce the pollutant reduction furthest and improve the social welfare extremely, making it the best ecological compensation. Finally, it is necessary to actively promote the formation of two-way ecological compensation in the upstream and downstream of transboundary watersheds to achieve long-term sustainable development of the watershed.

Microplastic (MP) distribution in river sediment, influenced by water regimes and pollution sources, remains understudied in the current literature. This study examines the combined impacts of seasonal variation and waterway differences on MP concentration in the sediment of the Saigon River and its tributaries, while identifying potential sources. Paired sediment samples were collected from eleven sites along the river and its tributaries during rainy and dry seasons. MPs from these 44 samples were separated, quantified, and characterized for a comprehensive assessment. The results revealed that MP concentrations in sediments ranged from 140 to 1200 items kg^-1, with predominant characteristics of fiber particles, white color, and particle sizes ranging from 200 to 500 μm. During the rainy season, MP concentrations were similar between the river (584 items kg^-1) and tributaries (553 items kg^-1), while during the dry season, tributaries exhibited statistically higher MP concentrations (737 items kg^-1) than the river (351 items kg^-1). Notably, the river, despite being farther from the sources, had a higher proportion of smaller MPs (<200 μm), while larger particles (>200 μm) were more prevalent in tributaries. These discrepancies are attributed to the combined impacts of water flow patterns and pollution sources, derived from residential, industrial, and agricultural activities. In brief, MP pollution in the river and tributary sediments is influenced by the interplay of seasonal variation and waterway characteristics, determined by water flow patterns and pollution sources. These findings emphasize the need for specific management strategies that account for spatial and temporal variations in MP distribution.

Global warming is becoming increasingly serious, with greenhouse gas (GHGs) emissions identified as a principal contributor. In response to the climate crisis, many countries are actively transitioning to renewable energy. Therefore, it is crucial to forecast GHGs emissions across different countries under varying degrees of energy transition to inform decision-making. Previous studies often focused on single regions and overlooked the developmental variance among countries. To address this problem, this study aims to project GHGs emissions in 39 major carbon-emitting countries globally, distinguishing between developed countries (DCs) and developing countries (LDCs). The results show that a 5.39% increase in global GHGs emissions from 2016 to 2021 and a 327.64% rise in the renewable electricity generation of LDCs. Additionally, this research develops various energy transition scenarios, employs Random Forest (RF) for feature selection, and utilizes an Extreme Gradient Boosting (XGBoost) model enhanced by Bayesian Optimization (BO) to forecast GHGs emission levels in DCs and LDCs. The performance test shows that RF-BO-XGBoost has higher stability and accuracy. The projection results indicate that the total emissions from all DCs and all LDCs will decrease as the scenario shifts from the baseline to the high energy transition scenario, by 1.22% and 5.23% respectively. Further, the study quantifies the impacts of energy transitions on GHGs emissions across individual countries, revealing that not all countries are likely to achieve optimal reduction under the high energy transition scenario. This study underscores the influence of transition costs and supports the climate policymaking.

Aquatic macrophytes, especially Vallisneria nana, provide essential spawning habitat and food resources for the threatened Australian lungfish (Neoceratodus forsteri). The availability of V. nana for lungfish has been dramatically reduced in some areas due to flood disturbances and macrophyte recovery is inhibited by reduced hydrochory due to river fragmentation by dams. Active transplanting of macrophytes may be a feasible restoration strategy to increase abundance of macrophytes, however, in the presence of macro-herbivorous aquatic animals, replanted beds may not persist due to intensive grazing. In this study, we analyzed the effects of environmental conditions on growth and expansion of transplanted V. nana in six 60 m² herbivore exclosures in the mid-Brisbane River in subtropical south-east Queensland. Following establishment, we also quantified the impact of aquatic herbivores on different patch sizes (15 m² or 45 m²) of restored V. nana to test the hypothesis that larger patch sizes may confer greater resistance to grazing using a paired control/treatment design. After initial planting, V. nana grew and spread rapidly throughout the exclosure plots, with mean % cover increasing from 5% to 71% on average and mean leaf length increasing from 20 cm to 54 cm on average over 161 days. Transplanted V. nana cover was significantly positively associated with water depth and finer substrate sizes and leaf length was significantly positively associated with water depth and water velocity but was unrelated to substrate size. Exposure to grazing significantly reduced cover of V. nana, however there was no significant effects of macrophyte patch size, grazing intensity, or environmental factors on changes in V. nana cover. Complete removal of exclosure fencing resulted in near complete loss of macrophytes within 7-22 days at all plots, indicating the macrophyte beds (15 m²-60 m²) were of insufficient size to resist grazing pressure. Our findings suggest that transplanting is a viable restoration method with exclusion of grazing, which is critical for creating resistant beds to disturbances and driving future macrophyte recovery. Further research is required to evaluate the feasibility and efficacy of alternative macrophyte restoration strategies in rivers to foster hydrochory and natural regeneration processes following flood disturbance.

The Middle Awash Basin (MAB) faces severe ecological degradation due to the rapid spread of the invasive Prosopis juliflora (P. juliflora), which threatens native vegetation. The study characterizes and predicts the spatiotemporal dynamics of rangelands affected by P. juliflora in the MAB. Using three Landsat images from ETM+ (2003) and OLI (2013 and 2023), we applied a supervised random forest (RF) classification technique processed on the Google Earth Engine (GEE) platform. This classification was integrated into an intensity analysis to examine temporal transitions between land use and land cover (LULC) classes. The predictive modeling included 12 variables, including climatic, topographic, edaphic, phenological, hydrological, and anthropogenic factors, using Terrset 2020. Using multitemporal satellite remote sensing, machine learning (ML), and cellular automata markov chain (CA-MC) methods, LULC was mapped from 2003 to 2023, and future scenarios were predicted up to 2060. The P. juliflora coverage quadrupled from 2.16% in 2003 to 8.61% in 2023, while rangelands were decreased by more than 25%. Models predict that P. juliflora could occupy 22% of the land by 2060 and over 40% of rangeland areas as of 2003, expanding two to three times faster than the intensities of the LULC baseline changes, primarily targeting rangelands. Our analysis is based on a single business-as-usual scenario; however, it highlights the worrying invasion patterns. The study's limitations include the absence of multiple scenarios and climate model integration, which could offer further insights into future invasion dynamics. Nonetheless, our findings indicate that the MAB faces imminent widespread ecosystem transformation without prompt action, which will severely affect pastoral livelihoods and biodiversity conservation. Therefore, we advocate for a management strategy involving prevention, eradication, and restoration measures, underpinned by policy reforms and stakeholder cooperation.