Journal of Environmental Management最新文献

Periphyton at the soil-water interface regulates nitrogen (N) cycling in rice paddies, yet its role in multi-pathway N losses is overlooked in agroecosystem models, leaving a critical gap in assessing the integrated environmental N footprint (NF) of rice systems. The core challenge lies in capturing the seasonal sink-source transition of periphyton under coupled environmental controls and upscaling its heterogeneous N accumulation to regional scales. Here we incorporated a process-based periphyton module into the rice version of the soil Water Heat Carbon Nitrogen Simulator (WHCNS_Rice) and upscaled site-scale observations to watershed-scale application via a soil organic carbon-based parameter transfer function (μ₀ = 6.05 + 5.77 × SOC, r = 0.79). The improved model, constrained by temporal measurements, published N-loss data, and field surveys from 14 paddy sites, reproduced the seasonal sink-source shift (r = 0.95) and the spatial heterogeneity of periphyton biomass N (PBN; mean 13.9 kg N ha^-1, CV = 30.1%) at watershed scale. Periphyton decreased NH₃ volatilization by 17.8%, while increasing denitrification, N leaching, and runoff N losses by 28.6%, 2.7%, and 7.0%, respectively, with crop N uptake remained nearly unchanged (+0.4%). As the reduction in NH₃ volatilization dominated the integrated response, the yield-scaled NF declined by 5%, from 9.3 to 8.8 kg N-eq t^-1 on average. The NF reduction scaled positively with PBN (r = 0.55, p < 0.001), with each 1 kg N ha^-1 increase in PBN corresponding to a 0.02 kg N-eq t^-1 decrease in NF, indicating greater mitigation potential in areas with larger PBN. These findings demonstrate that representing periphyton is essential for unbiased regional N footprint assessment, particularly in paddy fields with higher periphyton N storage, and provide a modelling framework to support region-specific evaluations.

Basins accommodate urban development, agricultural production, and ecological conservation, while ecological security patterns face dual pressures from built-up land expansion and cropland encroachment, threatening ecosystem stability. Existing studies have largely identified ecological security pattern conflicts from a whole-region perspective and developed uniform optimization strategies, making it difficult to reveal differences in conflict evolution under varying development orientations, while giving insufficient attention to the suitability of development strategies for different functional zones. Using the Dianchi Lake Basin as a case study, we examined the spatiotemporal evolution of ecological security pattern conflicts within a major function-oriented zoning framework. We simulated territorial spatial patterns for 2035 under five scenarios and evaluated preferred development pathways for different functional zones. The results revealed overall deterioration of the ecological security pattern, with ecological sources and core corridors becoming increasingly concentrated in the key ecological function area. Although total conflict area declined after 2010, fixed-basis analysis indicated that much of this reduction reflected contraction or reconfiguration of the ecological basis rather than a corresponding decrease in human land use pressure. Under the fixed 2023 ecological baseline, the food security scenario was preferred for the urban development area, while coordinated development was conditionally preferred for the major agricultural production area despite increased cropland-related conflict. The ecological security scenario yielded the lowest total conflict exposure in the key ecological function area. This study proposes differentiated conflict mitigation pathways tailored to the functional priorities of major function-oriented zones, supporting targeted territorial spatial governance in basins and other functionally heterogeneous regions.

This study presents a simple, locally applicable valorisation route for coarse Manech Tête Rousse wool, a currently underutilised by-product of dairy systems in the northern Basque Country. Raw fleeces were converted into wool pellets to enhance density and handling for soil amendment applications. Two fleece types-obtained from ewes bred under two farming systems-were mechanically ground without chemical or thermal pre-treatment and then pelletised at different compression ratios and moisture contents. A clear processing window was identified, enabling stable pellet formation with good mechanical properties, high attrition resistance and suitable bulk density for handling and field application. The pellets exhibited a high water-holding capacity (up to 288% w/w) and markedly delayed soil drying under simulated drought when mixed into a soil. A friction-driven densification mechanism is proposed to explain the influence of processing parameters on pellet density and durability. Overall, this work demonstrates a technically simple pathway to transform low-value coarse wool into high-density soil conditioners that enhance water retention. Further research is needed on agronomic performance, nutrient release and sanitary safety.

Ecological degradation and restoration in arid and semi-arid watersheds are jointly shaped by water limitation, ecosystem-function change, and intensive land-use disturbance. However, existing assessments often treat functional status, process pressure, subsequent response, and spatial diagnosis separately. To address this gap, we developed an integrated degradation-restoration framework (IDRF) for the northern Inner Mongolia section of the Yellow River Basin using long-term land-use data and four InVEST-derived ecosystem services. IDRF links ecohydrological functional status (F), land-use process disturbance (D), disturbance-function response positions, and annual degradation-restoration screening. Because high modeled water yield does not necessarily correspond to high ecological functioning under water-limited conditions, ecologically constrained water yield (WY*) was introduced as a dryland-oriented functional adjustment. The results showed that: (1) F stably integrated multiple ecosystem services and captured watershed-scale functional gradients, providing a consistent basis for F-D response analysis. (2) D extended disturbance assessment from static land-cover attributes to process-based pressure by integrating baseline disturbance, neighborhood exposure, edge fragmentation, land-use transitions, and water/wetland support; neighborhood context was an important structural component. (3) The functional-improvement diagnostic position (τr) was lower than the composite degradation diagnostic position (τd), and this relative ordering remained stable under paired spatiotemporal resampling, indicating that improvement-related responses generally occurred at lower disturbance levels than degradation-related responses. (4) Background maintenance, stable conservation, and restoration limitation were the dominant annual screening classes, with long-term changes characterized mainly by localized transitions. During the study period, stable conservation increased from 18.20% to 21.51%, while restoration limitation remained at approximately 18%-19%. Spatial-block evaluation further supported the within-watershed discrimination of model-defined events. Overall, IDRF provides an annually updatable, watershed-scale diagnostic framework for arid and semi-arid regions where water limitation and land-use pressure interact strongly, offering a methodological basis for spatially differentiated management and targeted field verification.

Herein, a novel SrTiO₃/CuFeS₂ heterojunction composite was successfully prepared to integrate visible-light photocatalysis with peroxymonosulfate (PMS) activation for efficient norfloxacin (NOR) degradation. The well-designed heterojunction promotes the separation and migration of photogenerated charges. The synergistic Cu-Fe bimetallic active sites and S^2- redox cycling endow the composite with outstanding PMS activation ability. Benefiting from the excellent structural stability of SrTiO₃, the composite effectively overcomes the agglomeration and deactivation defects of single-phase photocatalysts. Multiple reactive species (superoxide radical (•O₂^-), sulfate radical (•SO₄^-), singlet oxygen (¹O₂), holes (h⁺), and hydroxyl radical (•OH)) collectively dominate the oxidative degradation of NOR. The coupling of photocatalysis and PMS-based advanced oxidation efficiently compensates for the low efficiency and slow kinetics of single photocatalytic treatment. This study systematically clarifies the synergistic mechanism between photocatalytic excitation and PMS activation in the SrTiO₃/CuFeS₂ system, providing a feasible reference for the design of high-efficiency composite catalysts and the remediation of refractory antibiotic wastewater.

Electrochemical nitrate reduction (NO₃RR) to ammonia could couple nitrate removal with lower-carbon nitrogen recovery, but its eight-electron pathway makes activity and selectivity hard to control. A material-by-material view can hide how active-site structure, mass transfer and operating conditions work together. Here we assess NO₃RR through a joint structure-activity and reaction-system framework. We compare facet-controlled Pd, evolving Cu/CuO_x interfaces, Cu-Co tandem sites, isolated and symmetry-broken Fe centers, defect-rich Zr supports, metal-organic frameworks and other transition-metal systems. Across these materials, the evidence links selective ammonia formation to a matched sequence of nitrate capture, N-O bond cleavage, proton delivery, intermediate hydrogenation and product release. We also examine pulsed potentials, porous electrodes, flow cells and product recovery as ways to regulate transport and intermediate coverage beyond static catalyst design. However, reported metrics do not support a universal catalyst ranking because studies use different nitrate concentrations, electrolytes, potentials, cell designs and rate units. We therefore identify four priorities: direct tracking of active states during operation, shared testing rules, long-term tests with realistic feeds, and catalyst-reactor co-design at practical current densities. This framework connects atomic-scale catalyst design with device operation and sets clear tests for advancing nitrate-to-ammonia conversion.

Green space equality is fundamental to urban environmental justice and equal public service provision. However, existing studies have largely focused on static spatial distributions and supply, with less attention to the dynamic relationship between residents' mobility behavior and green space exposure. From a spatial-behavioral interaction perspective, this study develops an analytical framework for assessing equality in green space exposure. Taking the built-up area of Suqian, China, as a case study, we integrate mobile phone signaling data with multi-source geospatial data, apply the Gaussian two-step floating catchment area (Ga2SFCA) method to measure green space accessibility, and use origin-destination (OD) analysis to characterize long-distance (>1 km) green space visitation at the community level. Among the 319 communities identified as having low green space accessibility, 138 (43.3%) maintained relatively high levels of long-distance visitation, exhibiting a compensatory pattern in which residents accessed alternative green space services through cross-area travel. In contrast, 60 communities (18.8%) simultaneously exhibited low accessibility and low visitation, indicating a potential risk of polarization. These findings reveal marked differences among communities in their capacity to compensate for insufficient local green space provision through travel. Group comparisons showed that compensatory communities generally had higher housing prices, denser transport facilities, and more central locations. Spatial analysis further indicated that both compensatory and polarization communities exhibited spatial clustering, with a more pronounced pattern among polarization communities. Temporal analysis showed that mean hourly visitation between 09:00 and 17:00 was approximately 13.4% higher on weekends than on weekdays. Cross-period comparison further indicated that the median community-level long-distance visitation rate decreased from 0.1099 in May to 0.0676 in December, while community visitation rankings remained significantly and positively correlated across the two periods (Spearman's ρ = 0.403, permutation p = 0.0002), suggesting a degree of temporal persistence in relative visitation differences among communities. The findings demonstrate that low spatial accessibility does not necessarily result in low levels of observed green space visitation, although the capacity for behavioral compensation varies substantially across communities. This study expands the connotation of green space equality from spatial distribution equality to behavioral-based accessibility equality, and provides evidence for identifying risks of green deprivation and developing differentiated urban green space planning strategies.

Topographic position modulates soil moisture distribution and seasonal dynamics in alpine ecosystems, thereby shaping vegetation water-use patterns. However, whether dominant woody species occupying different hillslope habitats differ in the stability of their water-use strategies remains poorly understood at the hillslope scale. We investigated two dominant conifers, Picea crassifolia and Juniperus przewalskii, and a widespread alpine shrub, Dasiphora fruticosa across upslope, midslope, and footslope positions during the pre-rainy, rainy, and late-rainy seasons in an alpine catchment of the upper Heihe River Basin. By integrating δ²H and δ¹⁸O of soil and xylem water with a MixSIAR Bayesian mixing model, together with leaf δ¹³C, we quantified water sources for each species and evaluated water-use stability across hillslope positions and seasonal stages. Despite differences in dominant uptake depth, both conifers maintained relatively stable water-use strategies across slope positions and seasons. J. przewalskii persistently relied on deep soil water, which contributed 47% to 53% of total uptake, whereas P. crassifolia predominantly used shallow soil water, accounting for 44% to 65%. In contrast, D. fruticosa showed strong plasticity, with deep water uptake increasing from 16.2% to 41.0%, although this flexibility was constrained at upslope positions where available water was largely confined to shallow soil layers. Variability in leaf δ¹³C further indicated stronger physiological stability in the two conifer species within their respective hillslope habitats than in the shrub species, particularly at upper slope positions under greater evaporative demand. These findings suggest that water-use stability was associated with the sustained dominance of reliable soil water sources.

Nitrate nitrogen (NO₃^--N) and dissolved organic nitrogen (DON) are key forms of soil nitrogen leaching. Developing green technologies to mitigate both is crucial for reducing agricultural pollution, yet research on bioregulation methods remains limited. This study developed a nitrogen-transforming bio-organic fertilizer (BF) using a nitrogen-fixing bacterium and a putative nitrifying bacterium. A greenhouse pot experiment was conducted to evaluate the effects of BF on tomato growth, nitrogen leaching, soil microbial communities, and nitrogen-cycling functional genes. The effects of BF, organic fertilizer, urea, and microbial-urea combinations on tomato growth and nitrogen leaching were comprehensively quantitative analyzed. BF obtained the highest integrated score, increasing tomato biomass by 41.71-130.56% and reducing NO₃^--N and DON leaching by 38.38-88.16% and 7.42-51.14%, respectively. BF enriched beneficial microorganisms associated with nitrogen transformation (e.g., Galbibacter, Salinimicrobium), decreased the abundances of denitrification- and nitrification-associated genes (nirK, amoA, nxrB), and increased the abundances of genes associated with nitrogen fixation, nitrate reduction, and the glutamate cycle (nifH, narG, nrfA, glnA, gltB, gdhA). It also showed gene-abundance changes consistent with increased genetic potential for dissimilatory nitrate reduction (DNRA) and microbial ammonia assimilation. These findings suggest that BF may promote temporary microbial N immobilization in soil, as reflected by increased microbial biomass nitrogen (MBN), and improves crop nitrogen use efficiency. This strategy provides a promising approach for agricultural nitrogen management by simultaneously mitigating nitrogen leaching and improving crop nitrogen utilization.