Search Results (101)

Focusing on contrasting climate and land use pathways, this analysis explores the changing trajectories of water conservation function over time. An integrated framework combining the PLUS and InVEST models with Spearman’s correlation analysis and geographically weighted regression (GWR) was applied to examine the spatiotemporal heterogeneity and underlying drivers of water conservation function in the Chengdu–Chongqing Economic Zone during the period 2000–2020. Thus, it further predicted the evolution trend under two scenarios, namely SSP1-1.9 (Sustainable Development Pathway) and SSP2-4.5 (Medium Development Pathway), for the period 2030–2050. The findings reveal that: (1) Between 2000 and 2020, the spatial distribution of water conservation function shifted markedly, with low-value areas contracting and high-value zones expanding, alongside a progressive transition toward a predominantly medium-to-high functional structure. (2) In mountainous and hilly transition zones, precipitation (PRE) and forest cover proportion (FCP) exhibited notably positive effects, whereas evapotranspiration (PET) exerted a negative effect. In contrast, in plain and urbanized areas, built-up land proportion (BUP), population density (POP), and gross domestic product density (GDP) demonstrated pronounced negative effects. (3) Future simulations indicate that under the sustainable development pathway (SSP1-1.9), the combined area of high and extreme functional zones will recover by 2050, whereas under the moderate development pathway (SSP2-4.5), such extreme functional zones will be nearly eliminated. These results underscore the substantial impact of development pathways on regional water security and sustainability. Full article

Socio-spatial inequality remains a defining feature of climate vulnerability in South Africa, where historically formed patterns of segregation continue to shape uneven access to infrastructure, services, and environmental resources. This study presents a narrative review of how historical spatial planning has structured persistent disparities in exposure, sensitivity, and adaptive capacity across urban and rural landscapes. Evidence from the literature demonstrates that apartheid-era spatial planning established durable inequalities in water and sanitation provision, green infrastructure distribution, and proximity to environmental hazards, which continue to influence contemporary climate risk profiles. These inequalities are further reinforced through socio-economic stratification, particularly in the context of energy transitions, where access to private renewable energy systems is concentrated among wealthier households, while poorer communities remain dependent on unstable public electricity infrastructure. The review also incorporates land and soil systems as critical but often minimized dimensions of vulnerability, showing how soil degradation and unequal access to productive land contribute to livelihood insecurity and reinforce rural and peri-urban marginalization. In addition, emerging responses such as just transition frameworks, grassroots environmental justice movements, and energy democracy initiatives are examined with regard to the structural constraints that limit their effectiveness in addressing entrenched inequalities. Overall, the analysis highlights that climate vulnerability in South Africa is deeply embedded in historical and ongoing socio-spatial and socio-economic inequalities that continue to shape differentiated environmental outcomes. Full article

Unsustainable land-use transitions in peri-urban watersheds threaten both food security and ecological integrity. While Patch-generating Land Use Simulation (PLUS) and Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) models for ecosystem service (ES) assessment are commonly integrated, limited studies have simultaneously (i) accounted for multiple real-world spatial policies (e.g., ecological redlines) as hard constraints, (ii) targeted a comprehensive suite of ESs, and (iii) explicitly pursued synergies without relying on large-scale land conversion. To address these gaps, we developed a spatially explicit framework that integrates the PLUS and InVEST models to simulate four land-use scenarios and assess six ESs—grain yield, water yield, nitrogen export, phosphorus export, soil conservation, and carbon sequestration—in the Yuqiao Reservoir watershed, China, during 1990–2030. Against a backdrop of historical declines in cropland/grassland and key ESs due to construction expansion (1990–2020), the novel Comprehensive Development scenario—implementing slope-adaptive management and riparian buffers—synergistically increases grain yield (+0.55%) and carbon sequestration (+1.10%) while drastically reducing phosphorus export (−10.86%). It demonstrates that synergistic gains can arise from strategic spatial reconfiguration within a stable land-use area, advancing a paradigm from area-centric to configuration-centric optimization. This provides a quantifiable methodological basis and actionable policy reference for land spatial optimization in similar water-source watersheds. Full article

A 700 m pilot-scale cast iron pipeline reactor was operated for 120 days to investigate corrosion-stage evolution under reclaimed-water conveyance conditions. Sampling points were arranged at 50, 250, 450, and 650 m, and water-quality monitoring, coupon weight-loss tests, scanning electron microscopy (SEM), and high-throughput 16S rRNA sequencing were combined to characterize corrosion-rate variation, corrosion-product morphology, and microbial community succession. During transport, NH₄⁺ generally decreased while NO₃⁻ increased, indicating nitrification-related nitrogen transformation under aerobic conditions; meanwhile, PO₄³⁻ declined and DOC fluctuated, reflecting coupled physicochemical and biological processes. SEM observations showed a transition from loose porous deposits to relatively compact layered corrosion products, followed by local deterioration and renewed porous structures in the later period. The corrosion rate followed an increase–decrease–re-increase pattern rather than a monotonic trend. Therefore, corrosion acceleration (CA = dc/dt) was introduced as an auxiliary diagnostic indicator to identify whether corrosion activity was increasing, decreasing, or temporarily stabilizing. Microbial community analysis showed stage-associated variation in biofilm and nitrogen-transformation-related taxa, supporting the interpretation that corrosion evolution was jointly affected by water-quality change, corrosion-product development, and microbial succession. Overall, the combined interpretation of corrosion rate, CA, water quality, SEM morphology, and microbial succession provides a more informative basis for diagnosing corrosion-stage transitions in reclaimed-water cast iron pipelines. From a sustainability perspective, this diagnostic framework can support long-term operation, maintenance planning, and risk monitoring of urban reclaimed-water distribution infrastructure, thereby improving pipeline durability, reducing leakage and maintenance risks, and enhancing the reliability of reclaimed-water reuse systems. Full article

China has established the world’s largest municipal wastewater treatment system through rapid infrastructure expansion over the past two decades. However, under the transition from infrastructure expansion toward urban renewal and low-carbon development, wastewater systems are increasingly challenged by regional imbalances and structural inefficiencies. Existing studies have primarily focused on individual facilities or specific operational issues, while multidimensional system-level assessments remain limited. To address this gap, this study proposed a multidimensional assessment framework for evaluating wastewater system development in China from three dimensions: infrastructure adequacy, operational performance, and adaptive capacity. Based on national and provincial statistical data, regional disparities and development patterns were systematically analyzed using correlation analysis and hierarchical cluster analysis. Results showed that treatment capacity expansion in several provinces outpaced sewer network development, resulting in low hydraulic loading rates and underutilized facilities. Extraneous water infiltration remained a widespread issue, increasing unnecessary wastewater handling, energy consumption, and treatment burden. Reclaimed water development was influenced more strongly by policy-oriented planning and water resource constraints than by economic level alone. In addition, eastern coastal provinces generally demonstrated stronger infrastructure adequacy and operational performance, whereas several western and northeastern provinces remained constrained by insufficient adaptive capacity and sewer coordination. Overall, China’s wastewater sector is transitioning from treatment-oriented expansion toward system-oriented renewal. Future strategies should prioritize sewer rehabilitation, hydraulic efficiency improvement, reclaimed water integration, and adaptive infrastructure planning. The proposed framework can support future infrastructure monitoring, regional policy evaluation, and low-carbon wastewater system transformation. Full article

Urban wetlands are transitional sub-ecosystems, which have an important part in connecting the city sources of heavy metal pollution with freshwater ecosystems, and numerous studies have studied the nature of heavy metal pollution, though only several have investigated the consequences of heavy metals on the health of city dwellers residing in urban wetlands. The Monte Carlo simulation-based method of assessing health risks was employed to calculate the health risks related to the population residing within the study site as one of the measures taken within the framework of the present research to identify the health risks faced by the population when using the sediments of Huixian Wetland Mudong Lake, Guilin City, to evaluate health outcomes. The results showed that Cd and As had the highest geoaccumulation index values and were the most seriously polluted metals. The northeastern and northwestern areas of the lake exhibited a strong level of ecological risk, likely due to their proximity to anthropogenic pollution sources and slower water exchange rates. Non-carcinogenic risk indices (HI) for both adults and children were below 1, with children facing higher risk than adults. For carcinogenic risk, As, Cd, Cr, and Pb posed greater risks to children than adults, with 99.96% of the total carcinogenic risk (TCR) values exceeding the USEPA threshold of 1.00 × 10⁻⁴, indicating an unacceptable risk to children. Sensitivity analysis revealed that the hand–oral intake rate (IRing), As, and Cr were the main factors affecting the human health risk. These findings provide clear guidance for targeted risk control; priority should be given to pollution control of Cd and As, as well as protective measures in high-risk zones, to reduce children’s exposure. The results of this study provide a scientific basis for precise risk control and remediation measures in the region. Full article

With the rapid development of clean and low-carbon energy systems, non-metallic pipelines have become increasingly important in urban gas distribution, water supply, and emerging energy-transport applications, including hydrogen service. As a critical joining technology that governs system integrity and long-term operational safety, electrofusion welding requires a comprehensive and mechanism-oriented understanding beyond empirical process control. In this study, a review is conducted on research published over the past decade in the field of electrofusion welding of non-metallic pipelines, with emphasis on fundamental technical issues including the formation and evolution of temperature fields, characteristics of the molten fusion zone and defect development, and thermo-mechanical coupling with residual stress generation. Based on a synthesis of the literature, the review clarifies the global research landscape, core research communities, and underlying knowledge structure. The results indicate a clear transition of the field from empirically driven parameter optimization toward a mechanism-based and process-controllable paradigm centered on temperature field evolution, fusion zone development, and thermo-mechanical behavior. Current research hotspots converge on HDPE material adaptability, welding process regulation, and the long-term reliability of welded joints. Building on these insights, future research directions are discussed, including mechanism-driven process design, intelligent defect identification based on multi-source data, and full-life reliability assessment under service conditions. This review provides a theoretical framework to support process optimization and engineering application of electrofusion welding in non-metallic pipeline systems. Full article

Directive (EU) 2024/3019 updates and introduces new approaches to the collection, treatment, and discharge of urban wastewater. The directive aims to safeguard the environment and human health, reduce greenhouse gas emissions within the wastewater treatment cycle, improve energy efficiency, and foster the transition towards climate neutrality, while promoting the circular economy and the reuse of water resources. Within this framework, the reuse of treated urban wastewater emerges as a strategic lever to confront the growing challenge of water scarcity, to support circular economy principles, and to alleviate pressure on natural water reserves. This paper, starting from the European and Italian regulatory frameworks for urban wastewater management, provides an in-depth analysis of potential reuse pathways, highlighting both the advantages and the challenges associated with their application. Full article

Accurately quantifying the driving mechanisms of land surface temperature (LST) is fundamental to developing climate-resilient urban strategies. However, traditional linear models often fail to capture the complex nonlinear interactions and spatial non-stationarity inherent in urban thermal environments, especially when hindered by multicollinearity among morphological indicators. This study proposes a multi-scale spatial explainability attribution framework by integrating an XGBoost machine learning model with SHAP (SHapley Additive Explanations) to decipher the thermal dynamics of Changchun, a representative cold-region city in China. Utilizing a 500 m grid-based dataset, we incorporated 3D urban morphology (BVD), land cover (NDVI, NDWI), and socioeconomic factors. The results indicate that the XGBoost model achieves superior predictive performance (R² = 0.694) compared to traditional OLS models. SHAP global attribution identified Building Volume Density (BVD) as the primary warming driver, as its three-dimensional volume creates “thermal traps” through radiation trapping and reduced ventilation. Notably, NDVI exhibits a significant nonlinear “cooling threshold effect” at 0.3, beyond which its mitigation efficiency stagnates or even reverses due to vegetation fragmentation and heat-induced physiological stress. Furthermore, spatial mapping reveals a distinct “sign reversal” in NDWI’s impact, reflecting the dualistic thermal regulation of water bodies across different urban–rural gradients. These findings suggest that urban thermal management strategies should shift from merely restricting 2D surface occupancy (e.g., Building Density) to a more sophisticated approach focused on precisely controlling 3D volume intensity (BVD). This study provides a “point-to-area” diagnostic tool supporting a transition to spatially targeted urban planning interventions. Full article

Dietary transition is reshaping cropland demand and intensifying the challenge of matching food demand with land supply in rapidly urbanizing regions. This study examines how different dietary structure scenarios generate differentiated cropland demand, how these demands match with land supply under alternative development pathways, and how the land system responds when diet-driven demand is incorporated into land-use simulation. Using Jiangsu Province, China, as a case study, we developed a coupled diet–land simulation framework. On the demand side, five dietary structure scenarios—current, balanced, U.S., Japanese, and Greek—were constructed based on seven food categories, and their cropland demand in 2035 and 2050 was estimated using the cropland footprint approach and LSTM forecasting. On the supply side, the GeoSOS-FLUS model was used to simulate future land-use patterns under four development scenarios: natural development, cultivated land protection, ecological protection, and economic development. The cropland demand associated with each dietary scenario was then introduced into the land-use simulation process as an external demand constraint to identify land-system feedbacks and scenario differences. The results show that cropland demand differs markedly across dietary scenarios, forming a clear gradient from moderate-demand to high-demand diets. These differences are driven primarily by changes in the composition of key food categories, especially grains, livestock and poultry meat, plant oils, and fruits, rather than by proportional increases across all foods. In terms of supply–demand matching, the cultivated land protection scenario provides the strongest support for high-demand diets, whereas the natural development, ecological protection, and economic development scenarios are more compatible with moderate-demand dietary pathways. Once diet-driven demand is incorporated into land-use simulation, the land system shows clear sensitivity and strong scenario dependence. High-demand dietary scenarios intensify cropland compensation pressure and trigger structural reallocation among cultivated land and flexible land types. Under natural development, the response is mainly reflected in cropland expansion and grassland compression; under cultivated land protection and ecological protection, it is expressed more through substitutions among grassland, water bodies, and unused land; under economic development, the most prominent feedback is the competitive reallocation among cultivated land, construction land, and water bodies, with high dietary demand even constraining construction land expansion. Overall, the robustness of cropland supply–demand matching depends not only on the scale of dietary demand but also on how different dietary pathways interact with development-oriented land-use structures. Full article

Aquaculture sustainability in rapidly urbanizing regions is increasingly threatened by heavy metal contamination originating from complex anthropogenic land-use patterns. This study used an integrated model to evaluate the molecular-to-human health continuum in hybrid catfish (Clarias gariepinus × Clarias macrocephalus) sourced from Pathum Thani, Thailand’s primary aquaculture hub. We integrated geospatial land-use data with heavy-metal quantification, oxidative-stress biomarkers, and transcriptional profiling to assess how canal-specific water quality modulates fish health and consumer risk. The results revealed significant spatial heterogeneity in metal concentrations, corresponding to the province’s 27% urban–industrial land-use footprint. While water quality generally met regulatory limits, a pronounced aqueous–biotic discrepancy, “bioaccumulation paradox” was identified at certain sites, where muscle and hepatic tissues exhibited lead (Pb), chromium (Cr), and nickel (Ni) levels that substantially exceeded international safety standards. Biochemical and molecular analyses provided functional evidence of physiological distress, specifically significantly elevated malondialdehyde (MDA) levels, and the transcriptional modulation of cat, cyp1a, gpx, met, tnf, and star genes indicated that chronic metal exposure overwhelmed antioxidant defenses and induced potential endocrine disruption. Moreover, human health risk assessments revealed that the hazard index (HI) and target cancer risk (TR) exceeded unacceptable thresholds at multiple hotspots, indicating that Cr is a primary carcinogenic driver. These findings highlight a “GAP Paradox,” where farm-level certifications are insufficient to mitigate risks posed by the surrounding canal network. This study presents vital evidence-based risk profiles that necessitate a transition to a spatially based regulatory framework, incorporating geospatial land-use monitoring into national food safety policies to protect both aquaculture viability and public health. Full article

Following adjustments in regional water resource management policies and changes in hydrogeological conditions, significant shifts have occurred in Beijing’s water consumption patterns, which have effectively mitigated land subsidence and triggered a trend of ground rebound. This study systematically analyzed the spatiotemporal characteristics and transition mechanisms of ground deformation (subsidence-rebound) driven by water consumption changes, integrating InSAR, ICA (independent component analysis), and regional hydrogeological data. InSAR time-series analysis derived 2015–2023 Beijing Plain deformation data, with ICA identifying key drivers, supported by hydrogeological interpretation. Three primary patterns emerged: (1) quasi-linear subsidence from persistent deep groundwater overextraction; (2) rebound from Chaobai River basin engineered recharge; (3) “subsidence-to-rebound” dynamics due to reduced shallow groundwater extraction and enhanced precipitation infiltration. The results indicate that a regional rebound emerged 5.5 years after the initiation of the South-to-North Water Diversion Project (SNWDP), which quantifies, for the first time, the direct temporal lag between the initiation of water diversion and the geomechanical deformation response. ICA further revealed that deformation asymmetry (subsidence trend slope > rebound trend slope) correlates with aquifer lithology (clay vs. sand-gravel layers). The results offer a scientific framework for urban groundwater management and subsidence mitigation, not only in Beijing but also in analogous regions globally, highlighting a paradigm shift in ground deformation dynamics under integrated water governance. Full article

The coupling coordination between Urbanization Quality (UQ) and Water Ecological Carrying Capacity (WECC) represents a critical nexus for sustainable regional development within the Yangtze River Economic Belt (YREB). Focusing on 16 cities in Hubei Province over the period 2020–2024, this study constructed comprehensive indicator systems for UQ and WECC, Spatial Autocorrelation Analysis and Key Factor Analysis are then applied to analyze spatiotemporal evolution, identify key influencing factors. The results reveal that: (1) Both UQ and WECC demonstrated upward trajectories, with UQ increasing from 0.369 to 0.409, although WECC exhibited fluctuating patterns; (2) Spatial analysis identified pronounced “core–periphery” clustering effects with Wuhan as the dominant center, confirmed by the positive Global Moran’s I; (3) Hubei’s CCD advanced from 0.626 to 0.661, progressing toward initially coordinated stages, with Wuhan pioneering this transition, while 81.25% of cities remained at the moderately coordinated stage; (4) Grey relational analysis identified aquatic biological resources as the principal constraint, with piscivore biomass ratios and pension insurance participation rates (γ = 0.752) emerging as key biophysical and socioeconomic drivers, respectively. These findings provide empirical evidence for targeted interventions promoting balanced urban–water ecological development in the YREB, while contributing a novel analytical framework for examining UQ-WECC interactions in rapidly urbanizing regions globally. Full article

Rapid urbanization has transformed the face of Texas by converting agricultural and natural lands into expanding built-up areas. This study analyzes and simulates land-use and land-cover (LULC) changes in Kaufman County, Texas, one of the fastest-growing counties in the United States, using a hybrid Cellular Automata–Artificial Neural Network (CA–ANN) model within the Quantum Geographic Information System (QGIS) Modules for Land-Use Change Evaluation (MOLUSCE) framework. Multitemporal NLCD datasets (2001, 2011, and 2021) and six spatial drivers: Elevation, Slope, Aspect, Distance from Roads and Rivers, and Built-up Density were used in the modeling framework. Transition relationships were calibrated using the 2001–2011 LULC data, and the model was validated by simulating the 2021 LULC map from the 2011 baseline. The calibrated model was then used to simulate future LULC scenarios for 2031, 2041, and 2051. Model validation yielded an overall Kappa value of 0.84 and a correctness of 90.9%, indicating high similarity between the observed and simulated maps. The results indicate simulated urban expansion, with built-up areas increasing by nearly 30% by 2051 at the expense of cropland and open areas, with forest and water bodies slightly increasing, and wetlands remaining stagnant. The CA–ANN model effectively captured the nonlinear, spatially dependent land-transition patterns using open-source tools. These findings provided useful information for sustainable land-use planning and environmental management, with the potential to incorporate spatial modeling into regional development strategies in rapidly urbanizing areas of Texas. Full article

At the current stage, water resource shortages and significant regional disparities in resource distribution severely restrict China’s food security. Existing research primarily focuses on resource use efficiency, while lacking a systematic framework to distinguish between equality and equity in the coupled distribution of irrigation water, grain production, and nitrogen pollution across major river basins. The core objective of this study is to utilize the Concentration Index (CI) to construct a unified equity assessment framework, quantify the evolution of equality and equity in irrigation water use, grain production, and nitrogen loss to surface water in different river basins in China from 1992 to 2017, and determine the key influencing factors. For positive production resources, a distribution that benefits low-income groups is equity, while for pollution burdens, this distribution pattern is inequity. The results show that water shortages in Northern China have intensified, and higher income groups have obtained excessive benefits. The distribution of grain production has shifted from favoring higher income groups to favoring low-income groups, with the Concentration Index changing from 0.214 to −0.052, indicating an enhancement in equity. Irrigation water use has shown a certain degree of improvement, with the CI dropping from 0.023 to 0.017. However, nitrogen loss to surface water has exacerbated environmental inequality, with the CI dropping from 0.10 to 0.03, indicating that pollution burdens have shifted to low-income groups. Changes in equity across the country are driven by a small number of high-intensity grain production areas, and the key influencing factors include food security policies, urbanization, population size, and nitrogen fertilizer application. An asymmetric coupling relationship exists between water resource shortages and equity, and the regional economic foundation determines the formation of synergy or trade-offs. The findings underscore the necessity of transitioning from efficiency-focused to equity-focused agricultural governance in China. Targeted policies should include cross-basin ecological compensation mechanisms, differentiated technology promotion strategies, and integrated water–food-pollution management systems to balance food security, environmental protection, and social justice. Full article