Journal of Environmental Management最新文献

Eutrophication caused by internal nutrient loading from sediments remains a major challenge in lake ecosystem restoration. In this study, to address the endogenous pollution problem caused by the release of nitrogen (N) and phosphorus (P) from lake sediments, zero-valent iron (ZVI) was used as a remediation material to study its effect on the transport and transformation of N and P in sediments. It was found that the performance of ZVI-remediated sediments was enhanced, with a 41.26-72.62% increase in phosphorus adsorption capacity, an 84.91-99.15% decrease in potential phosphorus release, and an increase in the content of phosphorus bound to Fe/Al oxides and hydroxides (Fe/Al-P). Meanwhile, the denitrification rate (D_R) presented a 16.51-39.76% increase, and the microbial functional community changed significantly, with increasing relative abundance of denitrifying and iron-cycling functional microbes, including Hyphomicrobium and Trichococcus. And ZVI remediation increased the content of amorphous and nanoparticulate iron (oxyhydr)oxide phases (Fe_ox1), carbonate-bound iron (Fe_carb), crystalline iron (oxyhydr)oxides (Fe_ox2), and magnetite (Fe_mag) in the sediments. The process of ZVI enhancing N removal and P immobilization in sediments was positively associated with Fe_ox1, Fe_carb, and Fe_ox2, as the Fe-N cycle was promoted and phosphate was adsorbed and immobilized. The findings highlighted the potential of ZVI as an effective amendment and provided a scientific basis for in-situ ZVI remediation to control endogenous pollution in lake sediments.

Global warming is a pressing global challenge, and fully fluorinated greenhouse gases (FFGHGs) are the most potent greenhouse gases, with global warming potentials exceeding 7000 times that of CO₂. However, the latest insights into FFGHG emissions in central-eastern China (accounting for 63 % of the Gross Domestic Product and 55 % of the population in China) are lacking. Here, we present the latest estimates of FFGHG emissions in central-eastern China, derived from new atmospheric observations since August 2023 combined with an inverse modeling approach. Our results indicate that the bottom-up emission estimates by the Emission Database for Global Atmospheric Research (EDGAR) are lower by 27 %, 86 %, 99 %, and 100 % for CF₄, C₂F₆, C₃F₈, and c-C₄F₈, respectively. Moreover, the ratios of FFGHG emissions relative to CO₂ and non-CO₂ greenhouse gases (CH₄, N₂O, and hydrofluorocarbons) in central-eastern China from 2000 to 2023 increased substantially. Our findings reveal the increasing FFGHG emissions in China's most industrialized region, providing important insights for regional greenhouse gas mitigation.

Capturing and converting organic carbon from wastewater into volatile fatty acids (VFAs) through anaerobic acidogenesis and using these as a carbon source for biological nutrient removal, is regarded as a resource recovery process. Currently, the low efficiency of organic carbon capture from wastewater and conversion into VFAs hinders this process in practice. A technology that simultaneously enhances capture and conversion of real municipal wastewater through a bimetallic-modified biochar with iron and manganese (labelled Fe/Mn@BCs) is proposed. A synergistic enhancing effect on the COD capture was achieved 75 % removal when using Fe/Mn@BCs in combination with polyaluminum chloride (PAC), as opposed to using either alone. The yields of VFAs significantly increased 23.3 % in the presence of Fe/Mn@BCs. Insights into the mechanism of enhanced acid production were revealed through the enzyme activity of the respiratory chain and hydrolysis-acidification, as well as the analysis of functional gene expression and the dominant bacterial community. The abundance of electroactive bacteria increased significantly in the presence of Fe/Mn@BCs. Meanwhile, the enzyme activity of the respiratory chain, hydrolysis-acidification, and electron capacity increased correspondingly. Metatranscriptome analysis indicated that oxidative phosphorylation was activated under anaerobic conditions to generate more ATP and that the acetyl-CoA and pyruvate metabolic pathways were promoted to reduce CO₂ to acetic acid. Therefore, it can be inferred that the conductivity and capacitance of the modified biochar, which activates the extracellular electron transfer of electroactive bacteria, enhances VFA conversion through electroactive acidogenic fermentation.

Ecological compensation (EC) is a critical mechanism for sustainable management in national parks. However, current ecological compensation standards (ECS) formulations often rely on static, single-dimensional methods. These approaches fail to address the diverse and dynamic needs of different areas. This study addresses this gap by establishing a dynamic ECS framework. Our model integrates three multi-dimensional perspectives: carbon sink, ecosystem service value (ESV), and opportunity costs. We applied this framework to China's Yellow River Estuary National Park (YRENP). This case study provides a scientific basis for balancing ecological conservation with regional development. Results from 2000 to 2020 reveal three key findings. First, the study area's net carbon sink increased by 7.38 × 10⁴ t. Wetlands exhibited the highest carbon sequestration intensity per unit area. Second, the total ESV increased by 4.76 × 10⁹ yuan, primarily driven by wetlands. Within regulation services, hydrological regulation contributed the highest ESV. Third, the carbon compensation amount for the study area is 19.11 yuan/ha. The ECS threshold ranges from 2.00 × 10⁴ to 4.76 × 10⁴ yuan/ha. This research provides a robust, multi-dimensional framework for formulating ECS. It offers a new theoretical and methodological foundation for managing national parks and other protected areas.

The cultivated farmland and surrounding lake wetlands form a complex lake-adjacent agriculture-wetland system, where irrigation drainage plays a pivotal role as a critical link between agricultural production and wetland ecology. To mitigate eutrophication risks caused by nitrogen (N) and phosphorus (P)-rich agricultural drainage, particularly under the trend of expanding irrigation areas, it is essential to set appropriate threshold limits for agricultural drainage volumes to protect wetland ecosystems. This study introduces a decision-support framework for optimizing irrigation-drainage schemes by integrating a physics-based hydrodynamic-water quality model (Delft3D) with a machine learning surrogate model (FC-ANN), coupled with feasible domain analysis. Applied to the Chagan Lake system in Northeast China, the approach achieved over 97 % prediction accuracy and significantly improved computational efficiency. Through the use of Shapley Additive Explanations (SHAP), the study identified and quantified key factors influencing water quality, enabling transparent connections between drainage strategies and ecological outcomes. Results indicate that the optimal annual runoff volumes for the Qianguo and Da'an irrigation areas are 186 million m³ and 70 million m³, respectively, effectively balancing agricultural demands with wetland health. Furthermore, ecological engineering interventions-such as buffer wetlands and external water diversion projects-could expand the set of feasible drainage scenarios under future conditions. This framework provides a systematic and scalable solution for regional water resources management, offering scientific support for balancing agricultural development, wetland conservation, and sustainable resource governance under increasing environmental pressures.

Growing global food demand and freshwater scarcity are exacerbating pressure on agricultural systems, particularly in arid and semi-arid regions. While there is growing interest in sustainable land management, few studies have comprehensively addressed the trade-offs and synergies among water use, agricultural productivity, and ecological services. This study develops the MOWAE_CAO model-a multi-objective optimization framework that integrates water resource efficiency, net economic benefits, and ecosystem service values. By constructing four scenarios: S1 (water efficiency priority), S2 (economic priority), S3 (ecological priority), S4 (integrated optimization), and coupling the Non-dominated Sorting Genetic Algorithm II (NSGA-II) with entropy-weighted TOPSIS, the model identifies and evaluates Pareto cropping structure optimization under competing policy goals within the water-agriculture-ecology nexus. Applied to the Shiyang River Basin in northwestern China, the model revealed scenario-specific land allocation strategies. Using the actual 2021 cropping pattern as a baseline, Scenario 4 (S4) achieved the most balanced outcome, simultaneously improving all three sustainability criteria and integrated multi-objective solution. Compared to the baseline, S4 enhanced the net economic benefit by 4.05%, increased ecosystem service value by 3.67%, and improved crop water productivity for both maize and spring wheat. These findings underscore the potential of integrated, data-driven optimization to manage complex trade-offs and promote synergistic outcomes, offering actionable insights for sustainable land-use planning in ecologically vulnerable and water-scarce regions.

Synthesizing high-performance biochar adsorbents through facile and sustainable methods represents an effective strategy for the removal of volatile organic compounds (VOCs). This study introduced a one-step thermal treatment method using molten salt for the rapid synthesis of biochar from biomass. Compared to conventional processes for activated carbon production, the proposed method offers a simpler and more energy-efficient route. Adsorption experiments demonstrated that biochar consistently achieved superior adsorption capacities for benzene, toluene, and chlorobenzene over business activated carbon across various temperatures and concentrations, specifically achieving a maximum adsorption capacity of 691.88 mg/g for chlorobenzene at 30 °C. Density Functional Theory calculations further indicated the adsorption mechanism at the molecular level, supporting the experimentally observed adsorption hierarchy, in which chlorobenzene exhibited stronger adsorption than toluene, followed by benzene. The results also confirmed that surface oxygen-containing functional groups played a crucial role in significantly enhancing the adsorption of VOCs. The presence of oxygen-containing functional groups increases the number of active sites and the electrostatic potential on the carbon surface, thereby enhancing the biochar adsorption capacity for VOCs. Notably, hydroxyl groups, acting via hydrogen bonding, and lactone groups, acting via electrostatic interactions, were particularly effective, with an overall efficacy order of hydroxyl > lactone > semiquinone. These findings imply that molten salt heat treatment is a rapid and clean method for synthetic biochar with high specific surface area reaching 1851.72 m²/g, a total pore volume of 0.92 cm³/g, and oxygen content of up to 15.20 %.

Proper water management in rice fields is crucial for productivity, water use efficiency (WUE), and greenhouse gas (GHG) emissions. We aimed to evaluate the effect of water management systems on these agronomic and environmental subjects in a subtropical paddy rice. A field experiment was conducted over three growing seasons (GS-1, GS-2 and GS-3). The water management evaluated were: (i) continuous flooding throughout the whole season, from four-leaf phenological stage (V4) to harvest (CF); (ii) intermittent flooding (IF), where irrigation by flooding starting at V4, with water layer until seven-leaf stadium (V7), interrupted until the panicle initiation stage (R0), with water re-entering and maintaining the water layer until harvest; and (iii) saturated soil (SS), where the soil was maintained saturated. On average over the three harvests, compared to the CF, which presented an average productivity in the three harvests of 8.50 Mg ha^-1, the SS system provided a 9 % reduction in rice yield, which is equivalent to 0.77 Mg ha^-1. Across three growing seasons, compared to continuous irrigation (4914 m³), the reduction in water consumption in alternative systems was, on average, 1179 m³, which is equivalent to 23 %. IF and SS reduce water use by 18 and 30 % compared to CF, respectively. In the three seasons, the intensity of CH₄ peaks was lower in the alternative irrigation systems, than the inundation irrigation system. Averaged over three growing seasons, there was no difference due to water management on the seasonal emissions of N₂O, but seasonal emissions of CH₄ were average 58 % lower in alternative irrigation (IF and SS), than in the CF system. In comparison to CF system (4476 kg CO₂ eq. ha^-1), the alternative water regime promoted a decreased in 63 % in SS system (1655 kg CO₂ eq. ha^-1) and of 48 % in IF system (2322 kg CO₂ eq. ha^-1). Intensity Index of GHG emissions (YpGWP = pGWP/rice yield) were 62 % lower with SS system (205 kg CO₂ eq. Mg^-1 rice) and 45 % lower with IF system (292 kg CO₂ eq. Mg^-1 rice), than continuous irrigation system (533 kg CO₂ eq. Mg^-1 rice). Thus, IF and SS reduce global warming potential by ∼50 %. Despite new irrigation systems may strongly decrease GHG emissions and water use in subtropical paddy rice systems, it is crucial advances on water management aiming to avoid penalty in rice yields, which is a main reason for their lack of adoption by rice farmers.

Livestock manure composting is a significant source of nitrous oxide (N₂O), a potent greenhouse gas. While aeration mitigates anaerobic conditions, its precise impact on N₂O emission through microbial pathways remains unclear. This study investigated the effects of aeration rates [0.1 (AR1), 0.2 (AR2), and 0.3 L kg^-1 DM·min^-1 (AR3)] on N₂O emissions, enzyme activity, and nirK-gene denitrifier community during cattle manure composting. A novel integrated analytical framework (NIAF), integrating redundancy, Spearman, network, Mantel test, and Path analyses, was employed to decipher the mechanistic linkages. This study established 0.2 L kg^-1 DM·min^-1 (AR2) as the optimal aeration rate for minimizing N₂O emissions by 75.25 % while ensuring compost maturity (germination index 106.68 %; thermophilic phase >5 days). Higher aeration rate (AR3) yielded reduction (71.36 %) compared to AR1, attributed to suppressed N₂O reductase activity. Peak N₂O emissions occurred at mesophilic phase, reaching 1.35 (AR1), 0.32 (AR2), and 0.37 (AR3) mg·kg^-1 DM·h^-1, strongly correlating with nitrite accumulation (r > 0.95). Mechanistic analysis by NIAF​ revealed three microbial regulation pathways for N₂O emission mitigation in AR2: (i) suppression of keystone N₂O-producing genera (Pseudomonas:​ -9.01 %; Pusillimonas: ​-4.97 %), (ii) reduced nitrite reductase activity (15.7 % lower than AR1), limiting substrate supply; and (iii) enhanced competitive interactions among denitrifiers (124 % increase​ in negative network links), elevated connectivity (average degree 7.128) and optimized clustering (average clustering coefficient 0.156). NO₂^--N, pH, and unclassified_p_Proteobacteria (1.2122∗∗∗) were identified as the primary drivers for N₂O emission. This work provided a microbial ecological blueprint for precise aeration control to reduce N₂O emissions in composting.

Coastal wetlands, such as salt marshes, mangrove, and seagrass meadows, store large amounts of 'blue carbon', making their conservation and restoration a valuable climate-mitigation strategy. Scaling coastal wetland restoration as a nature-based solution in Australia hinges on the cooperation of private landholders, who own much of the land with restoration potential. This research closes a critical gap in understanding how private landholders weigh monetary versus non-monetary factors when deciding whether to restore and permanently protect wetlands on their properties. We surveyed coastal landholders nation-wide and ran a discrete-choice experiment to quantify the financial incentives and programme features most likely to incentivise wetland restoration and conservation. Choice data were analysed with random-parameter logit, latent-class, and hurdle models, while qualitative survey responses corroborated and contextualised model outputs. Our findings show that private landholders are generally interested in coastal wetland restoration but reluctant to participate in permanent restoration programs. Many can be enticed, provided the payment is sufficiently high in the context of current land values. Non-monetary elements also matter: programmes that minimise transaction costs through administrative assistance and program-assisted wetland maintenance receive higher stated participation rates, as do publicly funded programs and programs offering up-front payments. By quantifying the relative importance of these factors for private landholders, this study offers actionable guidance for designing, funding, and administering blue-carbon incentive programmes in Australia and comparable contexts. It also provides methodological insights for conducting stated-preference research with small, heterogeneous target groups.