Search Results (800)

In arid inland watersheds, the compounding impacts of climate change and intensive human activities have severely altered hydrological regimes and accelerated landscape degradation. However, conventional spatial planning often overlooks the critical coupling between subsurface hydrological processes and surface landscape dynamics. Taking the Manas River Watershed in northwestern China as a representative case, this research investigates the multi-scale dynamics of landscape patterns and their underlying spatial determinants. Integrating multi-period land-use data (2000–2020), landscape metrics, and the GeoDetector model, we diverge from conventional uniform buffer approaches by redefining riparian boundaries utilizing four distinct River–Groundwater Transformation (RGT) patterns. This methodological shift reveals critical eco-hydrological heterogeneities previously masked by fixed-width approaches. Our multi-scale analyses demonstrate that watershed-level landscapes exhibited a trajectory of declining diversity, transient recovery, and ultimately, intensified fragmentation, while riparian patches concurrently expanded and became increasingly homogenized. GeoDetector assessments indicate a fundamental shift in driving forces: early-stage variations were constrained by natural factors, whereas post-2010 dynamics became overwhelmingly dominated by socio-economic determinants, particularly agricultural expansion and GDP growth. Crucially, our RGT-coupled spatial analysis reveals a strong spatial association between agricultural sprawl and landscape risk hotspots concentrated within groundwater overflow zones—a pattern consistent with, but not directly demonstrating, disrupted vertical hydrological connectivity. Direct verification of subsurface mechanisms would require continuous piezometric monitoring beyond the scope of this study. Consequently, rather than generic zoning, we propose a multi-scale “hydro-spatial” governance framework featuring targeted interventions. By establishing strict agricultural redlines in vulnerable overflow zones and implementing eco-hydrological restoration tailored to specific RGT regimes, this paradigm delivers robust methodological insights for advancing precision spatial planning in fragile arid ecosystems. Full article

Soil contamination by heavy metals is a significant sustainability and ecological issue, impacting on the health of ecosystems and groundwater. This study assessed the efficacy of malic acid as a biodegradable and environmentally benign agent for the remediation of soils contaminated with cadmium, chromium, copper, and zinc. Two soils with contrasting textures were treated with a 10% malic acid solution at solid/liquid ratios of 1:5 and 1:10 for contact times of 2, 4, 6, and 8 h. The extraction efficiency varied depending on metal type, soil texture, and washing conditions. Cadmium removal ranged from 26% to 55%, zinc removal ranged from 10% to 25%, while copper showed variable extraction (5–45%) depending on initial soil concentration. Chromium exhibited the highest removal efficiency (30–90%), quantified as total chromium; however, the absence of speciation analysis (Cr(III)/Cr(VI)) represents a key limitation and may affect the interpretation of the removal performance. FTIR and UV–Vis analyses confirmed the formation of metal–carboxylate complexes and changes in soil functional groups during the washing process. In addition, significant mobilization of nitrogen and potassium was observed, whereas phosphorus remained relatively stable. The results highlight the influence of soil texture and multi-metal interactions on malic acid washing efficiency and provide a laboratory-scale environmental assessment of malic acid as a sustainable remediation alternative for soil remediation, while emphasizing the need for further evaluation regarding chromium speciation and post-treatment soil quality and sustainability impacts. Full article

Driven by global warming, increasing extreme precipitation events (EPEs) threaten low-lying coastal ecosystems. This study focused on the contemporary Yellow River Delta and established a continuous framework linking extreme precipitation, groundwater, and vegetation, based on long-term extreme precipitation changes during 1960–2022 and vegetation dynamics during 2001–2022. Using regional precipitation records, groundwater observations from 16 monitoring wells, and five-day kernel normalized difference vegetation index (kNDVI) data, we compared two EPEs that exceeded the 99th-percentile wet-day precipitation threshold and had complete precipitation–groundwater–vegetation observations. Our findings reveal that: (1) extreme precipitation was intensified in the study area, with an R99p trend of 19.1 mm/10 a; (2) vegetation disturbance was stronger and more persistent after the 2019 Lekima event, with a mean post-event kNDVI anomaly of −12.8%, whereas the 2022 Chaba event produced a weaker, later, and more spatially limited negative response; (3) groundwater response was also stronger in 2019, as the proportion of wells with above-surface water levels reached 43.8%, compared with 12.5% in 2022, indicating more extensive and longer-lasting inundation; (4) the shallowest post-event groundwater depth was significantly negatively correlated with kNDVI anomalies (r = 0.579, p < 0.001), and during the 2019 event, the kNDVI fell below about −17% when surface inundation lasted for 6 days. These results indicate that groundwater is a key hydrological link connecting extreme precipitation and vegetation response. This study provides new evidence for the identification and adaptive management of ecological risks in low-lying coastal deltas. Full article

Groundwater is a critical lifeline for ecosystems and human settlements in arid and semi-arid regions, yet it is increasingly vulnerable to the dual pressures of extreme climatic conditions and intensifying anthropogenic activities. This study investigated 24 groundwater and 4 river water samples to discuss the hydrogeochemical evolution and water quality suitability in the Tianjun Basin, a typical high-altitude arid basin on the northeastern Tibetan Plateau. The results indicate that groundwater is mildly alkaline (pH: 7.65–8.35) and predominantly fresh (TDS: 233.77–1061.42 mg/L). Hydrochemical facies evolve from HCO₃-Ca type in upstream areas to Mixed HCO₃-Na·Ca and Cl-Na types. Hydrochemical analysis suggests that silicate weathering and carbonate dissolution are the dominant natural processes, while cation exchange further modifies the ionic composition. Notably, anthropogenic nitrogen (NO₃⁻ and NH₄⁺) contamination, primarily from domestic sewage in the Tianjun Basin, has significantly impacted groundwater quality. Health risk assessment shows that infants are the most vulnerable group, with 16.67% of samples posing a non-carcinogenic risk via the oral pathway. Regarding irrigation suitability, while sodium hazards are generally low, a significant salinity hazard is identified due to elevated electrical conductivity in the arid environment. This poses a substantial risk of secondary soil salinization, necessitating strict salt management strategies to preserve long-term land productivity. These findings provide critical insights for the sustainable management of fragile groundwater resources in extreme arid environments. Full article

Landslides are a critical environmental hazard in mountainous regions like eastern Uganda, posing serious threats to lives, infrastructure, and ecosystems. While recent advances in geospatial technology have improved hazard assessment, existing research often lacks high-resolution, cloud-based analysis for dynamic landscapes such as the Mount Elgon region. This study addresses that gap by developing a landslide susceptibility map (LSM) using Google Earth Engine (GEE), which integrates remote sensing and geospatial data for scalable analysis. The main objective is to identify landslide-prone zones by analyzing eight conditioning factors, namely slope, elevation, vegetation cover, rainfall, land use land cover, soil type, soil moisture, and groundwater levels using the weighted overlay method (WOM). The methodology produced a classified LSM with zones of high (37.7%), moderate (58%), low (2%), and very low (2.3%) susceptibility, with validation via historical landslide data and ROC analysis yielding an AUC of 0.76, confirming strong predictive performance. The study underscores the value of GEE in hazard modeling and provides actionable insights for targeted risk mitigation, sustainable land use planning, and early warning system development in landslide-prone areas. Full article

Across Africa, drought seldom occurs alone. Rainfall deficits often coincide with heat, rapid soil moisture loss and reduced streamflow, producing compound events whose impacts exceed those of any single driver. This review synthesises station observations, satellite and reanalysis products, and climate model simulations to clarify where such events are most common, how they form, how they affect societies and ecosystems, and how risks are changing. A practical tiered definition tailored to African conditions is outlined and applied to identify five recurrent hotspots: the Sahel, the Greater Horn of Africa, southern Africa, the margins of the Congo Basin and the Guinea Coast. The review sets out a physically consistent sequence that links basin-scale sea surface temperature anomalies to shifts in monsoon circulation, and then to land processes that amplify and prolong heat and dryness through reduced evapotranspiration and soil-moisture memory. Documented impacts include lower crop and pasture productivity, pressure on rivers, reservoirs and groundwater, stress on hydropower and wider consequences for food and energy security. Compound drought frequency across these hotspots has risen by 18–55% since 1980, with the probability of the most severe events roughly doubling at 1.5 °C of global warming and tripling at 3 °C. The review highlights near-term priorities, including compound-aware monitoring, sub-seasonal-to-seasonal early warning and conjunctive water management. Full article

Under the combined pressures of climate change and irrigated cropland expansion, groundwater tables are declining rapidly across arid regions, thereby intensifying water limitation in riparian ecosystems. However, the mechanisms by which dominant riparian tree species coordinate multiple functional traits to maintain carbon–water balance remains poorly understood. This study investigated coordinated ecophysiological trait shifts of Populus euphratica Oliv. along a groundwater-depth gradient (2.19, 4.88, and 7.45 m) in the middle reaches of the Tarim River (China), hereafter referred to as shallow, middle, and deep groundwater depths, respectively. We quantified photosynthetic, hydraulic, stomatal, leaf anatomical and nutrient traits, and estimated long-term intrinsic water-use efficiency (WUE_i) from foliar δ¹³C. As the groundwater table declined, (1) photosynthetic capacity and photochemical performance decreased, whereas WUE_i increased markedly from 38.5 ± 2.9 to 54.2 ± 1.0 μmol mmol⁻¹, accompanied by the lowest transpiration rate at the deep groundwater depth (4.6 ± 0.5 mmol m⁻² s⁻¹); (2) stomatal and anatomical adjustments consistent with water-loss reduction were observed, including a significant decline in stomatal density from 93.5 ± 14.5 to 79.3 ± 17.4 pores mm⁻², and reduced stomatal size and stomatal area fraction (−20.3% and −32.7%, respectively); (3) the percentage loss of hydraulic conductivity increased, whereas sapwood-specific hydraulic conductivity declined, accompanied by greater sapwood investment relative to leaf area, with Huber value rising from 0.06 ± 0.02 to 0.11 ± 0.04 mm² cm⁻² at deep water depth; and (4) chlorophyll concentrations and leaf water content declined, whereas structural investment increased, as reflected by higher specific leaf mass and leaf dry matter content, and leaf nutrients were enriched, with total nitrogen and total phosphorus increasing by 67.1% and 42.0%, respectively. Trait-WUE_i relationships further indicated that WUE_i covaried most strongly with leaf anatomical and nutrient traits. These results demonstrate that increasing groundwater depth was associated with coordinated shifts in carbon assimilation, water-use regulation, hydraulic function, and nutrient allocation in P. euphratica. Such trait coordination may help explain how this species persists under chronic water limitation in arid riparian forests. Full article

Mercury (Hg) decontamination in active and decommissioned mining areas is a difficult task since Hg may affect environmental matrices and man-made materials. Despite its toxicity as an inorganic form being rather limited with respect to organic compounds (e.g., methyl-Hg), severe effects to human health and ecosystems are recognized. In this work, we review the geochemical activities carried out in the last 13 years at the Abbadia San Salvatore (AbSS) mining and production area. This site belongs to Mt. Amiata (Tuscany, central Italy), which is considered the third-largest Hg-district in the world. Air, water, soil and man-made materials within the AbSS area were investigated to verify to what extent such matrices were affected by Hg contamination. The geochemical investigations are used as important tools to proceed with specific remediation operations of edifices, mining structures and machineries as well as the local groundwater system. To the best of our knowledge, restoration of decommissioned areas affected by Hg contamination at a large scale, such as the AbSS exploitation and production site, is rather uncommon. Currently, the remediation activities in the AbSS area are going on and they are expected to be concluded at the end of 2026 or the beginning of 2027, when the former mining area will turn into a public archeometallurgical museum. Full article

In agriculture, the use of per- and polyfluoroalkyl substances (PFASs) as active substances in pesticides has increased over recent decades due to their chemical stability, their ability to alter cell membrane permeability, and their capacity to bind to target proteins. However, their intentional application to agricultural soils has led to progressive environmental accumulation. Their high persistence, mobility, and bioaccumulation potential, combined with documented toxicological effects, raise concerns for aquatic organisms and ecosystems. Monitoring surface and groundwater is essential to assess PFAS contamination. Data from the Italian monitoring plan show widespread contamination, despite the existing European regulatory framework designed to safeguard ecosystems and public health. The contamination is likely underestimated because monitoring programs currently target only a limited number of substances and PFAS metabolites and co-formulants are not included. Approximately 46 PFASs have been identified as active ingredients in pesticides, 29 of which are still authorized within the European Union, posing challenges for drinking water production and ecosystem protection. Existing regulatory regimes also differ in their evaluation procedures, which may lead to inconsistent conclusions regarding PFAS applications. Within the framework of the European “One Substance One Assessment” (OSOA) approach aimed at to ensuring the protection of human health and natural resources, this paper examines the properties of PFASs used as active substances in pesticides, their regulatory status, and their monitoring in Italy, highlighting the regulatory inconsistencies that result in the differential treatment of these substances compared with PFASs used in other sectors. Full article

Industrialization has led to the substantial release of heavy metals and organic pollutants into soil and groundwater, resulting in severe contaminated site issues that pose significant threats to ecosystems and human health. This review aims to systematically review the current development status and challenges of contaminated site remediation technologies, and explore the potential of artificial intelligence (AI) applications in site remediation, to provide a theoretical reference for advancing intelligent remediation. Conventional remediation technologies mainly include physical methods (e.g., solidification/stabilization (S/S), soil vapor extraction (SVE), thermal desorption, pump and treat (P&T), groundwater circulation wells (GCWs)), chemical methods (e.g., chemical oxidation/reduction, electrokinetic remediation (EKR), soil washing), and biological methods (phytoremediation, microbial remediation), along with combined strategies that integrate multiple approaches. Although these technologies have achieved certain successes in engineering practice, they still face common challenges such as risks of secondary pollution, long remediation periods, high costs, poor adaptability to complex hydrogeological conditions, and insufficient long-term stability, making it difficult to fully meet the remediation demands of complex contaminated sites. Subsequently, the potential of emerging technologies—including nanomaterial-based remediation, bioelectrochemical systems, and molecular biology-assisted remediation—is introduced. On this basis, the forefront applications of AI in contaminated site remediation are discussed, covering site monitoring and characterization, risk assessment, remedial strategy selection, process prediction and parameter optimization, material design, and post-remediation intelligent stewardship. Machine learning (ML), explainable AI (XAI), and hybrid modeling approaches have markedly improved remediation efficiency and decision-making. Looking forward, with advancements in XAI, mechanism-data fusion models, and environmental foundation models, AI is poised to drive a paradigm shift toward intelligent and precision remediation. However, challenges related to data quality, model interpretability, and interdisciplinary expertise remain key barriers to overcome. Full article

As a core area for soil and water conservation on the Loess Plateau and a national primary shale oil production zone, Qingyang City faces an increasingly acute contradiction between its inherently fragile ecological base and energy development activities. From the dual perspectives of ecological regulating services and production-supporting services, this study selected six key ecosystem services—habitat quality (HQ), soil retention (SR), carbon storage (CS), water yield (WY), food supply (FS), and grassland forage supply (GS)—to comprehensively assess their spatiotemporal evolution, trade-off/synergy relationships, and driving mechanisms from 2000 to 2020. The results indicate: (1) Significant changes occurred in the total amounts and spatial patterns of all ecosystem services during 2000–2020. HQ showed a fluctuating upward trend, while SR, FS, and GS increased overall; by contrast, CS and WY generally declined. (2) Ecosystem services exhibited a differentiated pattern characterized by “intra-category synergy and inter-category trade-off.” Regulating and supporting services were generally dominated by synergistic relationships, although clear differences remained among specific service pairs; provisioning services generally showed trade-offs with regulating services, among which the trade-offs between FS–HQ and between FS–GS were the most pronounced, whereas FS–CS showed a certain degree of synergy. (3) Driving force analysis revealed a continuous decline in the influence of natural factors and a sharp intensification of human activity factors. Groundwater level and land-use intensity became core drivers of pattern shifts, with their explanatory power increasing significantly. The study reveals that ecosystem services in Qingyang have rapidly transitioned from being dominated by natural hydrothermal conditions to being profoundly reshaped by energy development activities, exposing the region to the ecological risk of a “resource curse.” These findings provide a scientific basis and management insights for achieving coordinated development between resource exploitation and ecological conservation in ecologically fragile areas of the Loess Plateau. Full article

Climate change is altering the frequency, duration, and seasonality of low flows, which are critical for water availability, ecosystem functioning, and river management. Low-flow characteristics, defining the minimum, often seasonal, flow levels in rivers or streams primarily fed by groundwater, snow or glacier melt, or lake drainage, are essential for assessing hydrological droughts and water resource vulnerability. In the Upper Vistula River Basin, variable precipitation and rising air temperatures increase the risk of droughts, impacting both natural systems and human water use. This study analyzed long-term trends in annual low flows and associated parameters, including drought frequency, duration, and deficit volume, across 41 small- and medium-sized catchments. Two datasets were considered: 25 stations with 58-year daily discharge records (1961–2019) and 41 stations with 38-year records (1981–2019). Low flows were identified using the threshold level method (TLM) at 70% and 90% exceedance (FDC70 and FDC90). Trends were assessed with the Mann–Kendall test, and spatial drought patterns were mapped to evaluate regional variability. Deep and shallow low flows occurred at all analyzed cross-sections. For the period 1961–2019, deep low flows (FDC90) occurred almost annually in 18 of the 25 cross-sections since 2012. Statistically significant increasing trends in deep low-flow parameters were detected in five cross-sections for 1961–2019 and in seven cross-sections for 1981–2019. Shallow low flows (FDC70) occurred in all sections; four rivers exhibited annual shallow droughts during 1961–2019, whereas 12 rivers showed annual events in 1981–2019. Summer droughts predominated over winter events, reflecting enhanced evapotranspiration and higher seasonal water demand. These findings highlight the relevance of analyzing low-flow parameters for understanding hydrological droughts. Such information can support water resource management, planning, and ecosystem protection under variable climatic conditions. Full article

The Jordan Valley, a critical agro-ecosystem in Jordan, faces escalating challenges from chronic water scarcity compounded by environmental and socio-economic pressures, necessitating a systems perspective to understand cross-sector interactions beyond isolated sectoral issues. This study interprets socio-ecological interactions influencing sustainability outcomes in the region and identifies key feedback loops and adaptive responses under water scarcity through an integrated Socio-Ecological Systems (SES) and Water–Energy–Food–Ecosystems (WEFE) framework. Employing a qualitative document analysis (QDA) design, a purposive collection of peer-reviewed studies and institutional publications (n = 50) published between 2002 and 2025 was assembled and systematically coded using a structured deductive–inductive strategy grounded in SES components and WEFE domain interactions. Results reveal seven interconnected themes: water scarcity as a structural constraint, agricultural intensification and resource pressures, climate change as a stress multiplier, ecosystem degradation and service loss, pollution and environmental quality challenges, socio-economic vulnerability and livelihood constraints, and fragmented governance with coordination gaps. These themes highlight reinforcing loops where scarcity promotes groundwater reliance and non-conventional water use, intensification heightens salinity and contamination risks, climate variability escalates irrigation demands, and ecological degradation diminishes buffering capacity, while socio-economic limitations hinder adaptation and governance fragmentation impairs integrated planning and enforcement. While prior studies have examined water scarcity, agricultural intensification, or climate impacts in isolation, this study advances the literature by synthesizing these dynamics through an integrated SES–WEFE analytical lens, revealing reinforcing system feedbacks and governance constraints that are not visible within single-sector or descriptive syntheses. Full article

In this study, the contamination of two drinking water catchments in Australia by per- and polyfluoroalkyl substances (PFAS) was investigated. PFASs in water and sediment were found at hazardous concentrations in waterways affected by transport accidents 24 and 33 years earlier. The exact cause(s) of the PFAS pollution remains unclear due to large data gaps. Both locations experienced burning fuel tankers suppressed using PFAS foam. PFAS contamination of a Blue Mountains water supply triggered the closure of two drinking water reservoirs 3–5 km downstream of the accident site. PFAS contamination of Central Coast’s Ourimbah Creek was concentrated in two floodplain wetlands adjacent to the accident site. The Ourimbah PFAS-affected wetlands are within 500 m of a drinking water groundwater bore field and 1.2 km from a raw water offtake used as part of Central Coast’s drinking water supply. The Blue Mountains contamination has impaired the Blue Mountains World Heritage Area, with perfluorooctane sulfonate (PFOS) exceeding aquatic ecosystem protection guidelines by 100 times. The mean PFOSs in stream water near the area of the Blue Mountains road accident were 2.16 µg L⁻¹ and 213.3 µg kg⁻¹ in stream sediment. This research demonstrates how spillages of small quantities of PFASs can cause major harm due to their extreme persistence, and their levels have exceedance of environmental and health guidelines for decades, with major adverse implications for drinking water supplies and conservation areas. Full article

Uranium mining generates complex multi-element contamination that affects interconnected ecosystem components, posing long-term ecological and sanitary risks; this review places these impacts in a broad environmental context and aims to synthesize current knowledge on the distribution, migration, and accumulation of uranium and associated heavy metals in water, soil, and plants. A structured analysis of international peer-reviewed literature was conducted, focusing on documented pathways of metal release from tailings and waste dumps, geochemical controls on mobility, and biological uptake by vegetation. The reviewed studies consistently show that tailings and disturbed ore-bearing strata act as persistent sources of uranium and heavy metals (e.g., Cd, Pb, Cr, Ni, Zn, Mn, As), which migrate through infiltration, acid mine drainage, and atmospheric dispersion, leading to elevated concentrations in surface and groundwater and long-term accumulation in soils. Soils function as the principal sink controlling metal bioavailability, while vegetation reflects the bioavailable fraction and exhibits pronounced species-specific accumulation patterns. These processes establish an active “soil–water–plant” transfer chain that facilitates entry of contaminants into food webs. The synthesis indicates that combined uranium and heavy metal contamination represents a sustained ecological and public health concern in uranium-mining regions and underscores the need for integrated monitoring of soils, waters, and vegetation, along with quantitative risk assessment and scientifically grounded remediation strategies. Full article