Search Results (493)

Zinc processing generates large volumes of tailings enriched with potentially toxic elements such as zinc, lead, arsenic, and antimony, creating environmental challenges. Conventional disposal in tailings dams is associated with land occupation, contamination risks, and geotechnical concerns, reinforcing the need for more sustainable management strategies. This study presents a bibliometric and semi-systematic review of alkali-activated binders for the stabilization and solidification of zinc mine tailings, based on nine studies published between 2019 and 2026. The results indicate that this is a recent and expanding research field, with a marked concentration of studies in China. Current research mainly focuses on the links between microstructure, heavy metal immobilization, and mechanical performance. Alkali-activated systems, commonly based on blast furnace slag, fly ash, and coal gangue, can produce dense matrices with compressive strengths of up to 100.77 MPa and high immobilization efficiency. Their performance is largely governed by the type of reaction products formed, particularly calcium silicate hydrate, calcium aluminosilicate hydrate, and sodium aluminosilicate hydrate gels, which control microstructural development and stabilization mechanisms such as encapsulation, structural incorporation, and secondary phase formation. Overall, the reviewed studies suggest that alkali-activated binders have potential as alternative binders to Portland cement for the management and valorization of zinc mine tailings. Full article

This study investigated the associations among dam lactation number, passive immunity transfer, internal parasite burden, and weaning performance in female calves. Early consumption of high-quality colostrum is critical for effective passive immunity transfer, calf health, and long-term productivity. Colostrum composition may vary with management practices and dam lactation number, potentially influencing immunity and disease susceptibility. Forty-five cows and their female offspring (n = 45) were allocated to three groups by lactation number: first lactation (LAC1), second lactation (LAC2), and third lactation (LAC3) (15 cows and 15 calves per group). Calf birth weight was recorded. Colostrum immunoglobulin G (IgG) concentration was measured using a colostrometer and refractometer, and chemical composition (fat, protein, and non-fat solids) was analyzed. Fecal samples collected at 30, 60, and 90 days of age were examined for Eimeria spp. Colostrum IgG concentration, °Brix percentage, specific gravity, and non-fat solids did not differ among lactation groups (p > 0.05). LAC3 cows had higher colostrum protein content, while LAC1 cows had greater fat concentration (p < 0.05). Calves from LAC1 dams were lighter at birth than those from LAC2 and LAC3 dams (p < 0.001). The prevalence of Eimeria spp. was not influenced by lactation number, birth weight, or colostrum quality (p > 0.05), but treatment costs were higher in calves from LAC3 dams (p < 0.01). In conclusion, lactation number affected colostrum composition and calf growth but did not alter IgG concentration, underscoring the importance of effective colostrum management to improve calf performance and dairy system sustainability. Full article

Introduction: The Touvedo hydropower plant, located on the Lima River 47 km from its mouth, is equipped with a fish lift (2.14 m long × 1.29 m wide × 2.85 m high) on the left bank designed to facilitate fish migration past the dam. This mechanical system attracts fish by means of a guide current, traps them in a water-filled cage, and then lifts and releases them upstream, enabling passage over the dam. Within the framework of the Sustainability Policies from the EDP Group, particularly those related to Environment and Biodiversity, and under the Eel Management Plan, a long-term video-monitoring program has been implemented since 2011 to collect data on the species using the device and to evaluate its effectiveness. Objective: This study aims to present and analyze nine years of video-monitoring data collected across three programs—the “Action Plan for the Optimization of the Fish Lift at the Touvedo Hydroelectric Facility (2011/2014)”, which aimed to diagnose and assess the effectiveness of the fish lift and to define and implement measures needed to optimize its operation; “Video Monitoring of the Touvedo Fish Lift (2017/2020)”, that was carried out as a follow-up to the Action Plan; and more recently, a new video-monitoring project (2021–2024) which was implemented to expand the dataset and validate the patterns observed in the previous studies. Methodology: The fish lift was continuously monitored using an automatic video-recording system, which consists of a video camera installed at the top of the lift to capture images of the trapping cage during the final stage of its ascent, and a server for video storage. The trapping cage is lined with 20 cm × 20 cm white tiles to increase contrast and allow estimation of fish body length. Collected data included the timing of fish passage (day and hour), the number of fish per cycle, species-level identification and the estimated total length of each individual. Results: The European eel (Anguilla anguilla) has remained the dominant species using the lift, and, consistent with observations from Video-Monitoring 1, the Iberian barbel (Luciobarbus bocagei) has become the second most representative species, replacing the northern straight-mouth nase (Pseudochondrostoma duriense), whose proportion has declined. Brown trout (Salmo trutta) showed a slight but continued increase in Video-Monitoring 2, following the decrease recorded in Video-Monitoring 1 compared to the Action Plan. Conclusions: These results highlight the importance of continuing video monitoring of the Touvedo fish lift to assess its operability, confirm the observed passage patterns, determine the success of the implemented improvements, and evaluate the possible need for additional measures. Full article

LIFE REVIVE aims to restore ecological status and ecosystem services in the Lima and Vouga river basins (NW Iberian Peninsula), where hydromorphological alteration and hydropower-driven flow regulation are major causes of water bodies failing to reach Good Ecological Status under the EU WFD. The project targets key pressures such as longitudinal fragmentation by weirs and dams, artificial flow regimes, degradation of spawning substrates, and the spread of invasive aquatic plants, which strongly affect fish communities, including sea lamprey, salmonids, and other diadromous species. Technically, the project combines barrier removal or eco-adaptation, nature-like fish passes, and spawning-habitat renaturalisation with optimized environmental flow regimes (EFR) downstream of important hydropower systems, explicitly accounting for present and future hydroclimatic scenarios. Multi-scale ecohydrological modelling (species distribution models, habitat suitability models, GLM/GAM approaches) will quantify fish–flow–habitat relationships and support the definition of operational EFR guidelines that balance ecological requirements with hydropower and agricultural constraints through joint work with the main Portuguese hydropower operator, EDP. Impact evaluation is structured around a rigorous BACI monitoring design in intervention and control tributaries, using standard WFD biological indices for fish and aquatic/riparian vegetation, hydromorphological indices (HQA, HMS, RHS), and project-specific Key Performance Indicators for water quality, biodiversity, and habitat. Expected outcomes include the restoration of at least 51 km of rivers towards free-flowing conditions, reduced hydromorphological pressure in more than 20 km of heavily modified river stretches, and measurable increases in the distribution and abundance of fish species and native vegetation. A strong communication and capacity-building programme underpins public engagement, while a decision matrix for barrier prioritization, technical workshops, and pilot replications in additional basins (e.g., Alva, Mouro, Deva, and Tea in Galicia) are designed to maximize transferability, policy uptake, and long-term sustainability of the solutions beyond the project lifetime. Full article

The South American silver croaker, Plagioscion squamosissimus, holds significant importance for the artisanal fisheries operating in the sub-middle and lower courses of the São Francisco River, located in northeastern Brazil. Its complex horizontal movement patterns and habitat-use preferences are not fully understood in the waters of hydroelectric dam reservoirs, raising important questions for the rational and sustainable management of this species. This study aimed to identify the habitat use of P. squamosissimus individuals captured in three fishers’ associations (Olho D’água do Casado, Petrolândia and Rodelas). Individuals were collected between September 2023 and March 2024. A selection of 25 individuals per location from the same age group (+2 years) was used, following annual age estimation based on existing growth curves. Element-to-calcium (element/Ca) ratios in the otolith cores and edges were determined using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The data were analyzed using univariate and multivariate statistics to assess the degree of separation between individuals in relation to natal origin (otolith cores) and time of capture (otolith edges) from the three sampling sites. Significant differences in element/Ca ratios between core and edges of the otolith were observed for Ba/Ca, Mg/Ca, Mn/Ca and Sr/Ca ratios. These results indicate an ontogenetic change in the habitat use, in which similarity in core signatures suggests a common natal origin, likely influenced by shared environmental conditions of the individuals investigated in this study. Full article

Tauopathies, including Alzheimer’s disease, involve progressive neurodegeneration and sustained neuroinflammation. We present a multi-compartment transcriptomic atlas of 9.6-month-old PS19 tauopathy mice compared with wild-type (WT) controls (n = 8/group), profiling cortical mRNA, cortical non-coding RNA (ncRNA), and plasma small extracellular vesicle (pEV) ncRNA. In the PS19 cortex, mRNA sequencing identified 917 differentially expressed genes (DEGs), with microglial deconvolution revealing an association toward disease-associated microglia (DAM) gene signature and downregulation of genes involved in oxidative phosphorylation and cholesterol biosynthesis relative to WT. Cortical ncRNA profiling identified 466 differentially expressed ncRNAs, primarily circular RNAs (circRNAs; n = 331). In pEVs, 822 ncRNAs were differentially abundant, of which 657 circRNAs were identified in PS19 compared to WT mice. Cross-compartment integration suggest that pEV miRNA gene targets functionally mirrored genes involved in the brain’s inflammatory and metabolic failure. We identified a preliminary candidate signature of 33 ncRNAs, including miR-5114 (up in brain, down in pEV), circ_0008242 and circ_0002153 (up in brain and pEV), and circ_0007688 (down in brain and pEV), differentially enriched across both brain and periphery in PS19 compared to WT mice. These results suggest that the pEV non-coding landscape may partially reflect central tau-mediated changes in the brain transcriptional response. This study identifies circRNAs as the most numerically perturbed ncRNA class and provides a foundation for potential peripheral indicators of central brain tau pathology. Full article

The Loskop Dam is a major reservoir on the upper Olifants River in South Africa. Many human activities in the upper river catchment are causing contamination in the river including heavy metals. Although several studies have investigated water pollution in the river system, limited information exists regarding the spatial distribution and ecological risks of heavy metals in the Loskop Dam and their ecological implications. Seasonal heavy metal concentrations and ecological risks associated with heavy metal contamination in the dam were assessed. Though most of the heavy metal concentrations were below detection levels in the water, the concentrations were substantially higher in the sediments, with higher concentrations mainly recorded during winter than summer. Chromium and nickel concentrations in the sediments exceeded the permissible guideline values. Furthermore, contamination factor, enrichment factor and geoaccumulation index were used to determine the extent of chemical pollution, and ecological risk index was used to assess the potential ecological risks. The contamination indices found the sediments to be moderately to highly contaminated by Cr, Pb and Zn. However, the ecological risk values were low, indicating a low ecological risk of contamination posed by heavy metals in the dam. During winter, Cd had the highest ecological risk and during summer, the ecological risk was dominated by Pb, but the values indicated a low contamination (ER <40) and the potential ecological risk index values were also low (RI < 150). Nonetheless, effective conservation strategies are needed to prevent further degradation of the river system. Furthermore, the study reinforces the importance of addressing metal pollution and conservation of freshwater ecosystems, which aligns with the United Nations Sustainable Development Goal (SDG) 6, particularly in enhancing water accessibility and responsible sanitation management. Full article

Soil erosion is a global ecological and environmental issue that severely degrades terrestrial ecosystems. A range of soil and water conservation measures, notably the construction of check dams in gullies, have been widely implemented to mitigate soil erosion and sustain agricultural productivity. In this study, Ningxia province in China was selected as the study area. High-resolution Google Earth imagery and digital elevation model (DEM) data were integrated with three representative deep learning semantic segmentation models—FCN, U-Net, and DeepLab v3+—to achieve automatic extraction and spatial distribution analysis of engineered check dams. Model performance was quantified using overall accuracy (OA), F1-score, and mean intersection over union (mIoU), among other metrics. The results demonstrated that U-Net outperformed FCN and DeepLab v3+ across all evaluation metrics. On the test dataset, U-Net’s F1-score exceeded those of FCN and DeepLab v3+ by 3.89% and 7.08%, while mIoU increased by 2.17% and 6.57%, demonstrating superior boundary delineation. Based on the precise area extraction by U-Net, a piecewise empirical equation was subsequently developed to relate predicted silted land area to actual sediment volume, achieving R² values of 0.92 for small dams and 0.96 for large dams. Spatial distribution analysis revealed that check dams are predominantly concentrated in the southern mountainous and hilly-gully regions, moderately distributed in the central areas, and relatively sparse in the northern plains. Overall, this study demonstrates the feasibility and effectiveness of deep learning-based semantic segmentation for automated check dam mapping and sediment volume estimation. Full article

The sustainable management of water supply reservoirs requires analysis of spatiotemporal variations in nutrient levels, phytoplankton composition, and trophic status. The Katse Dam (KD) is a strategic raw water supply source that generates hydropower and sustains aquaculture. However, it is exposed to nutrient enrichment from mining and aquaculture, whose impact on its trophic status necessitates monitoring. This study applies the organic pollution index (OPI), the modified pollution index (MPI), and Carlson’s trophic state index (CTSI) to assess the trophic status of KD. The results from the first decade (FD) (2003–2013), when the intensity of mining and aquaculture activities was minimal, were compared with the results from the second decade (SD) (2014–2024) when there was higher activity. The MPI revealed that KD transitioned from a contaminated status during the FD to a greatly contaminated status during the SD. KD shifted from mesotrophic to eutrophic in the transitional zone and from eutrophic to hypereutrophic in the lacustrine zone. The cyanobacteria Radiocystis sp. replaced Asterionella sp. and became the most abundant algae in the SD, followed by the diatom Flagilaria sp. Principal component analysis (PCA) indicated stronger correlations between NH₄, PO₄, NO₃, and NO₂, while canonical correspondence analysis (CCA) indicated a strong correlation between PO₄ and Fragilaria sp. in the SD. The OPI classified KD water quality as excellent, with the exception of the lacustrine zone, where the water quality was polluted in 2016 and 2021. The data analysis revealed how long-term variations in KD water chemistry and phytoplankton influenced trophic status. This study thus provides water managers with a template for assessing water quality to secure the strategic value of the KD. Full article

Climate change, depleting fossil fuel reserves, and instability in petroleum prices are driving developing economies to explore cost-effective, efficient, and sustainable energy sources such as hydropower. However, there is an ongoing debate regarding the relevance, suitability, and impact of mega-dams. Much of the existing research on mega-dams examines this debate through the lens of development theories. However, mega-dams impact a wide range of stakeholders at local, national, regional, and global levels, necessitating exploration of their role from a socioeconomic perspective. This interdisciplinary case study draws knowledge from management, sociology, and economics and provides a comprehensive account of multi-stakeholder perspectives on the impact of a mega-dam and addresses the research question: How do stakeholders perceive the impact of the Merowe Dam on agricultural livelihoods, and how do they interpret the role of governance processes? Participants included farmers, a focus group with 10 members from the affected communities, and 32 key informant interviews from non-governmental organizations, political actors, academics, businessmen and leaders in the catchment areas of the Merowe Dam, Sudan. The findings suggest that despite some concerns about motivations and processes of mega-dam commissioning, these projects are perceived as beneficial for long-term and sustainable socioeconomic growth and gaining support for renewable energy use in developing economies. The participants reported that modernization of agriculture, following the establishment of the dam, increased crop yields, e.g., wheat production has increased per hectare. Farmers’ income and irrigated land have increased substantially per family due to an increase in land sizes allocated to relocated communities, leading to an overall increase in land size. Therefore, with improved processes in both pre- and post-commissioning stages, transparency, accountability, and deeper stakeholder engagement, mega-dams can facilitate a smoother transition from fossil fuels to large-scale hydropower on one hand and livelihood enhancement through agriculture and other income generating activities on the other. Full article

Under the dual pressures of global climate change and rapid urbanization, the spatial contradiction between urban expansion and flash flood disasters in mountainous dam areas is increasingly evident. However, the mechanisms by which the multi-dimensional characteristics of urban expansion affect regional flash flood susceptibility (FFS) remain unclear, limiting scientific guidance for source-level disaster prevention. This study uses Zhaotong City, a flash flood-prone area in the lower Jinsha River basin of southwestern China, as a case study. Using land use and multi-source remote sensing data from 2000 and 2025, we identify urban expansion patterns and morphological characteristics, apply the XGBoost-SHAP model to evaluate flash flood susceptibility and determine dominant factors, and employ the generalized additive model (GAM) to quantify the nonlinear responses of expansion dimensions to FFS. Results show the following: (1) Urban expansion in Zhaotong City is primarily edge (51%) and leapfrog (46%), clustering along river valleys, dam areas, and transportation corridors. (2) The XGBoost model performs well (AUC = 0.877). Elevation, slope, normalized difference vegetation index (NDVI), and precipitation are the primary natural factors influencing FFS. About 15.66% of the city falls within the high/very high FFS zones, mainly in the Zhaolu Dam area, riverbanks of main and tributary streams, and the urban built-up area. (3) Urban expansion-related indicators explain 28.6% of the spatial variation in FFS, with leapfrog expansion as the primary driver (contribution rate 32.75%). Disorderly urban growth and morphological imbalance significantly increase flash flood susceptibility. This study provides a scientific basis for spatial planning, flash flood prevention and control, and climate-adaptive urban development in similar mountainous dam areas in Southwest China and Asia, supporting regional sustainable development goals. Full article

Ensuring the sustainability of ageing water-storage infrastructure is an increasingly urgent challenge under climate-driven hydrological extremes. In the Republic of Korea, approximately 18,000 small and medium-sized agricultural reservoirs—many several decades old—pose escalating risks to downstream communities and threaten progress toward SDGs 6, 11, and 13. This study presents a 0.5 m airborne LiDAR-based, GPU-accelerated two-dimensional shallow-water simulation of a hypothetical breach of the Geumosan Reservoir, South Korea, using a MUSCL + HLL solver verified against the Ritter (1892) and Stoker (1957) analytical dam-break solutions. Two scenarios are compared: Run A with a uniform Manning coefficient (n = 0.035) and Run B with spatially variable roughness derived from the Korean Ministry of Environment land-cover map (mean n = 0.0711). Mass conservation is preserved to within 0.01% during the closed-domain phase. Spatially variable roughness expands the total inundated area by 8.5% (3.05 → 3.31 km²) while reducing the Extreme-hazard zone, defined by the DEFRA hazard rating HR = h(v + 0.5), by 24% (1.49 → 1.14 km²); arrival times in the downstream urban corridor are delayed by up to 30 min. Uniform Manning assumptions therefore systematically overestimate extreme-hazard extents while underestimating the broader shallow-inundation footprint—biases comparable in magnitude to breach-parameter uncertainty. By delivering reproducible, georeferenced hazard, arrival-time, and damage-class maps for emergency action planning, the proposed framework supports risk-informed and sustainable management of ageing reservoir infrastructure and community-level disaster resilience aligned with the Sendai Framework and SDGs 6, 11, and 13. Full article

Water security in rapidly urbanising river basins is increasingly threatened by untreated city effluents, industrial discharges, and legacy agricultural contamination. The Tula River basin in central Mexico illustrates this issue, absorbing the majority of Mexico City’s effluent while sustaining a heavily exploited aquifer beneath one of the nation’s largest irrigation districts. This study provides an integrated assessment of surface water and groundwater quality throughout the basin, including the Endhó Dam and its associated aquifer. Water quality analysis revealed severe surface water contamination (WQI > 300), driven by untreated sewage and inadequate sanitation infrastructure. Elevated COD, BOD, and nutrient concentrations indicate significant organic loading and eutrophication risk. Near Tula City, arsenic, copper, and zinc were detected at levels posing direct risks to human health. Groundwater quality was comparatively favourable, with 71% of wells recording WQI < 100; however, arsenic exceeded permissible limits more than twentyfold in select wells, attributed to geological sources. The detection of SVOCs in both hydrological compartments confirms cross-compartment contamination. Point-source reduction alone is insufficient for aquifer recovery; comprehensive sanitation strategies and long-term monitoring are urgently required. These findings carry direct relevance for water governance in megacity-dependent basins globally, where urban, agricultural, and geological stressors demand integrated management approaches. Full article

Water balance calculations at the watershed scale are fundamental to water resource planning and the sustainable management of limited water supplies. These calculations rely on stream and canal gaging networks operated by local, state and federal entities, whose availability has varied over time due to cost, staffing constraints, and limitations on suitable gaging locations. The Green River Basin (GRB) above Fontenelle Dam in Wyoming illustrates this trend, where the number of operational stream gaging sites has varied over time and the majority of locations have less than 15 years of streamflow records. Recent advancements in the ability to perform streamflow reconstruction and estimate agricultural water use offer a new avenue for estimating the water balance for watersheds with discontinuous gage observations. But the use of these datasets and approaches has not been tested. Therefore, this paper proposes and tests a novel framework that combines discontinuous streamflow observations with new datasets (OpenET, ET-Demands, and GEOGLOWS) to calculate monthly water balances in the GRB from water year 1991 to 2023. Focusing on two main test basins, the Green River and the New Fork River, the integration of modern datasets enables the successful calculation of the water balance in the GRB with good agreement with downstream gaging records, achieving a Nash–Sutcliffe efficiency (NSE) of 0.88 for the New Fork River and 0.80 for the Green River. By improving the ability to quantify water balance components in data-limited basins, this framework supports more transparent water accounting and informed decision-making for sustainable water management, including irrigation planning, drought response, and long-term resource allocation in semi-arid river systems. Full article

The stability of upstream tailings remains a critical geotechnical challenge due to the inherently weak mechanical properties of fine-grained mine tailings. This study investigated a tailing improvement method using (i) emulsified polymer and (ii) combinations of recycled gypsum and cement kiln dust (CKD). A comprehensive experimental program—including unconfined compressive strength (UCS) analysis, direct shear tests (DSTs), and oedometer consolidation tests—was conducted to assess the performance of various treatment mixtures. The results showed that blends of CKD and gypsum, particularly at a 1:2 ratio and a 10% dosage, significantly improved shear strength, reduced compressibility, and lowered hydraulic conductivity by over an order of magnitude. The inclusion of plaster (commercial gypsum) further enhanced the UCS by more than 100% compared to recycled gypsum and increased the cohesion (c’) values from 0 to 32.8–47.2 kPa. The compression index (c_c) decreased from 0.15 to 0.05, and the maximum volumetric strain (ε_v) at an applied effective stress of 800 kPa decreased from 17% to 5%. Emulsified polymer treatments also enhanced the mechanical and hydraulic properties of the clayey tailings; however, the overall improvements were lower than those achieved with CKD–gypsum blends, suggesting that further optimization of the polymer concentration or its combination with mineral additives may yield better results. These findings offer a foundation for further research into the use of polymers in geoenvironmental applications, particularly for erosion control, contaminant encapsulation, and hydraulic barrier development. Overall, this study highlights the potential of using industrial by-products, such as CKD and gypsum, as sustainable, cost-effective materials to improve tailing performance, while identifying promising directions for polymer-based solutions in geotechnical engineering. Full article