Search Results (476)

The Valencia region exemplifies the intricate interplay of climate, urbanization, and human interventions in managing hydrological systems amidst increasing environmental challenges. This study explores the escalating risks posed by flood events, emphasizing how anthropogenic factors—such as urban expansion, sediment exploitation, and inadequate land use—amplify the vulnerabilities to extreme weather patterns driven by abnormal Greenhouse Gas (GHG) concentration. Nature-based solutions (NBS) like floodplain restoration and dam removal are analyzed for their benefits in enhancing ecosystem resilience and biodiversity but are critiqued for unintended consequences, including accelerated river flow and sedimentation issues. This study further examines the impacts of forest fires, exacerbated by land abandonment and insufficient management practices, on soil erosion and runoff. A critical evaluation of global policies like the Sustainable Development Goals (SDGs) reveals the tension between aspirational targets and practical, locally-driven implementations. By advocating historical insights, ecological restoration practices, and community engagement, the findings highlight the importance of adaptive strategies to harmonize global frameworks with local realities through modeling and scaling simulations, offering a replicable model for sustainable flood mitigation and resilience building in Mediterranean contexts and beyond. Full article

Miscanthus is considered a promising candidate for the cultivation of marginal land. This land poses unique challenges, and experiments have shown that the “establishment phase” is of paramount importance to the long-term yield performance of miscanthus. This experiment analyzes novel miscanthus hybrids and how their establishment on marginal land can be improved through agronomic interventions. Experiments took place at two sites in Germany: at Ihinger Hof, with a very shallow soil profile and high stone content, and at Reichwalde, where the soil was repurposed river sediment with low organic matter, high stone content, and a compacted lower horizon. These marginal conditions functioned as test cases for the improvement of miscanthus establishment agronomy. Four hybrids (Miscanthus x giganteus, Gnt10, Gnt43, and Syn55) and agronomic treatments such as plastic mulch film, miscanthus mulch, inoculation with mycorrhizal fungi, and fertilization were tested in two years at both sites in 2021 and 2022. Specific weather conditions and the timing of planting were strong determinants of establishment success and no single treatment combination was found that consistently increased the establishment success. Plastic mulch films were found to hinder rather than help establishment in both these locations. Chipped miscanthus mulch caused nitrogen immobilization and stunted plant growth. At Ihinger Hof the novel seed-based miscanthus hybrid Gnt43 produced twice the biomass of other hybrids (7 t ha⁻¹) in the first growing season. Gnt10 yielded well in 2021 and showed impressive tolerance to water stress in the summer of 2022. No treatment combination was found that consistently increased the establishment success of miscanthus hybrids across sites and years. Novel genotypes consistently outperformed the standard commercial miscanthus hybrid Miscanthus x giganteus. Gnt10 may be a promising candidate for the cultivation of water-stress-prone marginal lands, due to its isohydric behavior and high yield potential. Full article

The slope lands of the Loess Plateau represent a critical region impacted by soil erosion, which directly contributes to the globally recognized high sediment concentration in the Yellow River. However, the extent to which sloped farmland contributes to soil loss remains scientifically contentious. In this study, farmland with an initial slope gradient of 20° was selected for the experiment, and three decades of field monitoring data (1990s–2020s) and the Universal Soil Loss Equation (USLE) model were used for comparative calculation. The data indicated that the model-predicted soil loss rate in sloped farmland from the 1990s to the 2020s was calculated to be 62.48 t·ha⁻¹·yr⁻¹. Field-measured values averaged 45.67 t·ha⁻¹·yr⁻¹, whereas the current value is approximately 15.00 t·ha⁻¹·yr⁻¹. Anthropogenic disturbances, including tillage, manual weeding, and ovine grazing, mean that the topsoil of slope farmland has undergone cumulative displacement of 450~870 cm in 30 years, which is resulting in progressive slope gradient reduction from 20° to 5°. The soil erosion rates exhibited exponential decay characteristics, and finally gradually reached the level of flat farmland. When using the USLE model, the evolving slope gradient must be incorporated, rather than the slope angle extracted by DEM. Therefore, the key finding of this study is that the primary sources of soil loss in the Loess Plateau are non-agricultural slopes and gullies. Conversely, soil erosion on slope farmlands does not constitute a critical problem requiring urgent intervention. This finding should attract the attention of the local agricultural sector. Full article

The present study focuses on the sources and spatial distribution of potentially toxic elements (PTEs) and organic pollutants in water, canal bed sediment, and soil in the Versiliana urban park, an inclusive green area near the coast in the densely populated Versilia Plain of Tuscany. Surface water and bed sediments from canals crossing the urban park were collected at 10 stations during four different surveys to account for hydrological seasonality. Groundwater was collected in a survey through 10 piezometers. Eleven shallow soil samples were also collected, with the aim of evaluating the potential release of pollutants. Groundwater ranged from Ca-HCO₃, to NaCl, CaCl₂, and Na-HCO₃ water types, indicating conservative mixing and cation exchange processes during seawater intrusion. Most waters from canals belonged to the Ca-HCO₃ hydrofacies; a salinization shift, due to hydraulic connection with saline groundwater and soil sea salt dissolution, is observed. The concentration of most PTEs in groundwater and canal water is below Italian regulatory thresholds, with the only exception being As, which exceeds the legal limit in some samples. In most sediments, Ni, Cr, Zn, and As exceed the threshold effect concentration, and in some cases, the probable effect concentration. Geogenic PTE sources are attributed to metalliferous mineralization that characterizes the upstream Versilia River basin catchment. However, local PTE inputs from vehicular emissions and local industrial activities have been highlighted. Arsenic in sediments originated from geogenic sources and from arsenical pesticides, as indicated by the analysis of organic compounds, highlighting the legacy of the use of organic pesticides that have settled in bed sediments, in particular malathion and metalaxyl. The arsenic risk-based screening level in soil is lower compared with the regulatory threshold and with the measured concentration. Full article

Water–sediment evolution and attribution analysis in watersheds is one of the research focuses of hydrogeology. An in-depth investigation into the spatiotemporal variation of water and sediment at multiple spatial scales within the basin, along with a systematic assessment of the respective impacts of climate change and human activities, provides a scientific foundation for formulating effective soil and water conservation practices and integrated water resource management strategies. This research holds significant implications for the sustainable development and ecological management of the basin. In this study, the Mann–Kendall nonparametric test method, double cumulative curve method, cumulative anomaly method, and cumulative slope change rate analysis method were used to quantitatively study the effects of climate change and human activities on runoff and sediment load changes at different spatial scales in the Huangfuchuan River basin. The results show that (1) from 1966 to 2020, the annual runoff and annual sediment load discharge in the Huangfuchuan River basin showed a significant decreasing trend. Among them, the reduction in runoff and sediment in the control sub-basin of Shagedu Station in the upper reaches was more obvious than that in the whole basin. The mutation points of runoff and sediment load in the two basins were 1979 and 1998. The water–sediment relationship exhibits a power function pattern. (2) After the abrupt change, in the change period B (1980–1997), the contribution rates of climate change and human activities to runoff and sediment load reduction in the Huangfuchuan River basin were 24.12%, 75.88% and 20.05%, 79.95%, respectively. In the change period C (1998–2020), the contribution rates of the two factors to the runoff and sediment load reduction in the Huangfuchuan River basin were 18.91%, 81.09% and 15.61%, 84.39%, respectively. Among them, the influence of precipitation in the upper reaches of the Huangfuchuan River basin on the change in runoff and sediment load is higher than that of the whole basin, and the influence on the decrease of sediment load discharge is more significant before 1998. There are certain stage differences and spatial scale effects. (3) Human activities such as large-scale vegetation restoration and construction of silt dam engineering measures are the main reasons for the reduction in runoff and sediment load in the Huangfuchuan River basin and have played a greater role after 1998. Full article

Habitat suitability assessment for forest and grassland ecosystems is a critical component of ecological restoration and land use planning in the Loess Plateau, aiming to advance soil and water conservation and foster sustainable ecological environment development. Despite progress in vegetation restoration, systematic evaluations of habitat suitability in complex geomorphic regions like the Loess Plateau remain scarce, particularly in balancing hydrological and ecological trade-offs. The Yanhe River Basin (7725 km²), a sediment-prone tributary of the Yellow River, exemplifies the challenges of soil erosion and semi-arid climatic constraints, making it a critical case for evaluating restoration strategies. This study employed a comprehensive approach utilizing Analytic Hierarchy Process (AHP), Geographic Detector, mathematical statistics, and other methods. An evaluation indicator system and methodology were established to assess the suitability of forest and grassland habitats in the Yanhe River Basin, evaluating the suitability and quality improvement potential under the current land use conditions. The results indicate: (1) The dominant factors influencing the suitable distribution of forests include photosynthetically active radiation (PAR), soil total phosphorus content, annual precipitation, and elevation. For grasslands, the dominant factors include photosynthetically active radiation, annual average temperature, elevation, and annual precipitation. (2) In the watershed, forestland and grassland areas classified as moderately suitable or higher cover 1064.9 km² and 4196.9 km², accounting for 91.9% and 94.7% of their total respective areas, indicating a generally rational spatial allocation of forest and grassland ecosystems. (3) The improvable area for forests measures 366 km² (34.4% of moderately or higher suitability zones), with most already meeting coverage thresholds. In contrast, grasslands have an improvable area of 2491.6 km² (59.4% of moderately or higher suitability zones), where over half of the area remains below coverage thresholds corresponding to their habitat conditions. (4) Forests can adopt natural restoration-focused low-intensity interventions through strengthened closure management, while grasslands require spatially tailored measures—such as precipitation interception and enhanced stewardship—targeting suitability-based potential grades, collectively achieving overall improvement in grassland vegetation coverage. This study represents the first systematic evaluation of forest–grassland habitat suitability in the Yanhe River Basin, elucidating its spatial distribution patterns and providing critical insights for watershed-scale ecological restoration. Full article

Phosphate pollution in aquatic environments leads to eutrophication and harmful algal blooms, significantly impacting ecosystems and water quality. The current study evaluates the effectiveness of surface-modified activated carbon (SMAC) in suppressing phosphate release from sediments. Using soil samples from Daecheong Lake, the performance of SMAC adsorption for phosphate was analyzed under various SMAC modification scenarios. Experiments showed that SMAC achieved approximately twice the phosphate removal efficiency compared to conventional activated carbon, with increasing effectiveness under higher flow velocities. Additionally, SMAC significantly reduced phosphate concentrations within the sediment layers, proving its effectiveness in the soil remediation process as well. The results highlight SMAC as a promising solution for mitigating pollutant release in rivers, lakes, and coastal areas, offering both short-term and cumulative long-term benefits for water quality improvement and ecosystem protection. Full article

As emerging contaminants, rare earth elements (REEs) have undergone significant anthropogenic enrichment in aquatic systems. This study investigates the REE concentrations, major metal elements, and grain size in surface sediments from the East Tiaoxi (ETX) River in eastern China, a small urban river subjected to substantial anthropogenic influences. Total REE concentrations of surface sediments ranged from 133.62 to 222.92 mg/kg with MREE enrichment and HREE depletion. REE concentration and fractionation were strongly correlated with Ca, Fe, Mg, and Mn, which may reflect the control of clay minerals, Fe-Mn oxides, and specific heavy minerals, and differences in REE behavior between riparian sediments and riverbed sediments highlighted the impact of hydrodynamic sorting and chemical weathering on REE distribution. Anthropogenic activities, particularly urbanization, were found to increase REE concentrations, especially at urban-adjacent sites (e.g., RBS2 and RS2), while natural processes such as soil transport and chemical weathering primarily contributed to REE variation at other sites. The enrichment factor and ecological risk assessment revealed that the enrichment and moderate risks associated with REEs occurred in river sediments adjacent to urbanized areas, though agricultural impacts were less pronounced. The findings emphasize the combined influence of urbanization and natural processes on REE distribution and ecological risks in the ETX River basin and underscore the need to prioritize urban-derived REE contamination in environmental management strategies. Full article

Sediment transport plays a crucial role in shaping coastal and riverine environments, influencing both natural and human activities. This study assesses sediment supply from the entire basin of a touristic zone of Cyprus, where coastal erosion and sediment deposition impact infrastructure, tourism, and environmental sustainability. Human activities, such as dam construction, further disrupt the sediment balance. This study focuses on Coral Bay and Potima Gulf, a popular tourist destination along an ~11 km shoreline in western Cyprus, fed by four small rivers draining a total area of 66.5 km². The sustainability of the Coral Bay–Potima system is threatened by the Mavrokolympos stream dam, which traps upstream sediments. Using the USLE method, mean sediment yield at the basin outlet is estimated at 888 t km⁻² yr⁻¹. These findings underscore the link between watershed processes and sustainable coastal management, emphasizing the need for integrated sediment transport assessments in touristic coastal zones. Full article

Few studies have addressed the coupling of arsenic (As) and nitrogen (N) geochemistry in natural soil. This research focused on the vertical distribution and coupling behavior of As and N in coastal wetland sediments. Pore water and sediment from barren wetlands and coastal wetlands near three estuaries (Guanhe River, Sheyang River, and Liangduo River) in central Jiangsu Province of China with Spartina alterniflora (S. alterniflora) were sampled, which were analyzed for total As content and speciation and N inorganic fractions. The bacterial community was investigated through 16s rDNA sequencing; diversity indices were calculated. The As change trend in pore water of surface sediment with increasing depth was opposite to that of NO₃⁻, possibly because NO₃⁻ promoted arsenite (As(III)) oxidation to arsenate (As(V)). Increased NO₃⁻ contents seemed to mitigate As toxicity. The vertical distribution of NH₄⁺ indicated anaerobic ammonium oxidation and iron (Fe) ammonium oxidation to reduce Fe oxides, resulting in As release, especially in the deeper sediment. High-throughput sequencing analysis revealed some potential bacteria possibly involved in As-N geochemical coupling, such as Bacillus and Psychrobacter, which can couple denitrification with As oxidation, and Sva1033, which may favor ammonium oxidation-induced As release. Our results suggest that the N-driven oxidation of As(III) and the ammonium oxidation-induced As release can be relevant to As-N coupling processes in the coastal wetland and emphasize the importance of microorganisms in such processes. This research deepens our understanding of As-N coupling in natural coastal wetlands, providing a theoretical basis for controlling As pollution. Full article

Spoil heaps have become a major source of anthropogenic soil erosion, but the hydrological responses and erosion mechanisms of in situ slopes under rainstorms remain poorly understood. We performed simulated rainfall experiments at real estate (Site A), railway (Site B), and railway station (Site C) construction sites, as well as spoil sites (Site D) in China’s Yangtze River Delta. Rainfall parameters, surface runoff, interflow, vertical soil moisture profiles, and sediment yield were monitored: (1) Hydrological responses differed significantly across the sites due to soil structure complexity; stable erosion after the first rainfall event was not achieved at any site except Site C. Soil erosion was the strongest at Site C, followed by Sites D, B, and A. After the second rainfall event, erosion was stable, increasing, and decreasing at Sites A, B and C, and D, respectively. (2) Runoff and the soil loss rate were positively correlated (R² > 0.7), and the slopes of the fitted regression lines were highest for Sites B and C, followed by Sites D and A. (3) Soil erodibility values based on field data were 0.0029, 0.1164, 0.1974, and 0.0989 t·hm²·h·hm⁻²·MJ⁻¹·mm⁻¹ for Sites A, B, C, and D, respectively. (4) The soil bulk density, gravel content, and silt content were key factors contributing to the severe erosion of field spoil heaps. Spoil heaps from different project types exhibited distinct hydrological and erosional behaviors, which necessitates targeted mitigation strategies to reduce severe erosion and landslide risks. Full article

The migration and driving factors of microplastics (MPs), as an emerging pollutant, have been reported in plateau lakes. However, whether MPs can accumulate to an extreme degree in the local aquatic organisms of plateau lakes remains unclear. Therefore, the present study mainly aims to investigate the MPs accumulated in tissues of grass carp as well as reveal their migration processes and driving factors in the Caohai watershed, a typical plateau lake in southwest China. Density flotation (saturated NaCl solution) and laser direct infrared imaging spectrometry were used to analyze the relative abundance and morphological characteristics of MPs, respectively. The results showed that the MPs’ abundance in soil, water, and sediments ranged from 1.20 × 10³ to 1.87 × 10⁴ n/kg, from 9 to 223 n/L, and from 5.00 × 10² to 1.02 × 10⁴ n/kg, respectively. The contents and composition of MPs in forestland soils were more plentiful in comparison with cultivated land soils and marshy grassland soils. Polyethylene (PE), polyvinylchloride (PVC), PA from caprolactam (PA6), and PA from hexamethylene diamine and adipic acid (PA66) were detected in grass carp, and PE was detected in all organs of grass carp. MP concentrations in the stomach, intestines, tissue, skin, and gills of grass carp ranged from 54.94 to 178.59 mg/kg. MP pollution probably mainly originated from anthropogenic factors (road traffic, farming activities, the habits of residents scattered around the study area, etc.) due to the Caohai watershed’s considerable proximity to Weining city. In addition, wind, land runoff, rivers, and atmospheric deposition in the locality directly and indirectly promoted MP migration. Our results suggested that although there is moderate MP pollution in soil, water, sediment, and grass carp in comparison with other areas, it is necessary to pay attention to PE and PVC migration via the various environmental media and the risks associated with consuming the local grass carp. The local government can make several policies to reuse and recycle agricultural film to alleviate local PE and PVC pollution. Full article

Check dams play a pivotal role in soil and water conservation engineering as they mitigate debris flow and decelerate the slope of the river channel by intercepting sediments, thereby preventing disasters. However, as ecological conservation and landscape integration have become significant, functions, safety, harmony, and aesthetics with the surroundings must be considered in the design of check dams. In this study, a questionnaire survey was conducted based on scenic beauty estimation (SBE) and image segmentation using artificial intelligence to evaluate the landscape quality of soil and water conservation projects. Data were collected from the photos which were segmented into vegetation, structure, sky, land, and water. The proportion of each segment was calculated to explore the relationship with the scenic beauty of the landscapes. Regions with prevalent vegetation and water received favorable evaluations, whereas areas with a higher proportion of land were less preferred. Even when vegetation was present in high quantities, an unorganized arrangement was less desirable. Identified key factors influencing the scenic beauty of the landscape can be considered in the design of soil and water conservation engineering projects. Full article

Beavers play a key role in creating temporary water reservoirs that significantly impact the natural environment and local river hydrology. The primary aim of this study was to assess the potential of increasing the number of beaver dams (Castor spp.), as an alternative method of water retention in the environment. Research conducted on three small lowland streams in central Poland revealed that beaver dams, even in modified riverbeds, enable the formation of shallow floodplains and ponds. Innovative analyses considered the structural materials of the dams and their impact on river hydromorphology and sediment transport. The findings emphasise the importance of beavers in water retention processes, the stabilisation of water levels during low flows and the protection of biodiversity. The study also demonstrated that beaver dams play a critical role in storing surface- and groundwater, mitigating drought impacts, reducing surface runoff, and stabilising river flows. These constructions influence local hydrology by increasing soil moisture, extending water retention times, and creating habitats for numerous species. The collected data highlight the potential of beaver dams as a tool in water resource management in the context of climate change. Further research could provide guidance for the sustainable utilisation of beavers in environmental conservation strategies and landscape planning. Full article

Environmental DNA (eDNA) is DNA isolated from environmental samples. It is distinctly different from genomic DNA, which is extracted directly from biological specimens. eDNA metabarcoding technology is a novel surveillance tool combining eDNA and second-generation high-throughput sequencing technology. Different from conventional approaches and biomonitoring techniques, eDNA metabarcoding technology (eMT) has many advantages, such as promising timeliness and accuracy, lower time consumption, and low cost, and thus is widely used in ecological and environmental monitoring, including that in rivers, lakes, oceans, soils, and sediments. As a tool, eDNA metabarcoding technology supplements the evaluation of environmental qualities by monitoring both the diversity of aquatic biology communities and target species. In addition, it is essential to understand the limitations of eDNA metabarcoding technology in practical applications. As a tool, eDNA metabarcoding technology features high efficiency, providing indicators of environmental health and allowing for the indirect estimation of the impact and extent of water pollution with respect to aquatic ecosystems. It provides new insights for aquatic environment protection. Full article