Search Results (140)

Artisanal and small-scale gold mining (ASGM) poses significant environmental challenges globally, particularly due to mercury (Hg) use. As an example, in Ecuador, Hg use still persists, despite its official ban in 2015. This study investigated the geogenic and anthropogenic contributions of potentially toxic elements (PTEs) in the Ponce Enriquez Mining District (PEMD), a region characterized by hydrothermally altered basaltic bedrock and Au-mineralized quartz veins. To assess local baseline values and identify PTE-bearing minerals, a comprehensive geochemical, mineralogical, and petrographic analysis was conducted on bedrock and mineralized veins. These findings reveal distinct origins for the studied PTEs, which include Hg, As, Cu, Ni, Cr, Co, Sb, Zn, and V. Specifically, Hg concentrations in stream sediments downstream (up to 50 ppm) far exceed natural bedrock levels (0.03–0.707 ppm), unequivocally indicating significant anthropogenic input from gold amalgamation. Furthermore, copper shows elevated concentration primarily linked to gold extraction. Conversely, other elements like As, Ni, Cr, Co, Sb, Zn, and V are primarily exhibited to be naturally abundant in basalts due to the presence of primary mafic minerals and to hydrothermal alterations, with elevated concentrations particularly seen in sulfides like pyrite and arsenopyrite. To distinguish natural geochemical anomalies from mining-related contamination, especially in volcanic terrains, this study utilizes Upper Continental Crust (UCC) normalization and local bedrock baselines. This multi-faceted approach effectively helped to differentiate basalt subgroups and assess natural concentrations, thereby avoiding misinterpretations of naturally elevated element concentrations as mining-related pollution. Crucially, this work establishes a robust local geochemical baseline for the PEMD area, providing a critical framework for accurate environmental risk assessments and sustainable mineral resource management, and informing national environmental quality standards and remediation efforts in Ecuador. It underscores the necessity of evaluating local geology, including inherent mineralization, when defining environmental baselines and understanding the fate of PTEs in mining-impacted environments. Full article

Juglans neotropica Diels, an Andean native species classified as endangered by the IUCN, holds significant potential for reforestation and sustainable forest management programs. This study evaluated seed quality, phenotypic variability, and early establishment under nursery and field conditions in southern Ecuador. Three provenance sites—The Tundo, The Victoria, and The Argelia—were evaluated during the nursery phase, and two (The Tundo and The Victoria) in plantations, applying four pre-germination treatments: control, mechanical scarification, hot water, and water-sun exposure. Parameters assessed included seed weight, size, viability, germination, survival, and growth across three planting environments: secondary forest, riparian forest, and pasture. Significant differences in seed morphometry were observed among localities, while germination was influenced by treatment but not provenance. Seed viability remained high for up to six months, decreasing with a 2% loss of moisture. Survival reached 100% with urea application, and 96% of individuals exhibited straight stems after one year. No significant differences in growth were found between localities; however, basal diameter was highest in the pasture (13.2 mm/year⁻¹), and total height was greatest in the secondary forest (54.8 cm/year⁻¹). These findings provide key technical evidence to optimize the propagation and establishment of J. neotropica in ecological restoration and forest production contexts. Full article

The mean annual water balance is essential for evaluating water availability in a catchment and planning water resources. Climate change alters this balance by affecting precipitation, evapotranspiration, and overall water availability. This study analyses the impact of climate change on the mean annual water balance in the Catamayo catchment, a key water source for irrigation and hydropower in southern Ecuador and northern Peru. A Budyko-based approach was employed due to its conceptual simplicity and proven robustness for estimating long-term water balances under changing climatic conditions. Using outputs from 23 Global Circulation Models (GCMs) under CMIP6’s SSP2-4.5 and SSP8.5 scenarios, the results indicate increasing aridity, particularly in the lower and middle parts of the catchment, which correspond to arid and semi-arid zones. Water availability may decrease by 26.3 ± 12.3% to 33.3 ± 17% until 2080 due to negligible changes (statistically speaking) in average precipitation but rising evapotranspiration. However, historical precipitation analysis (1961–2020) reveals an increasing trend over this historical period which can be attributed to natural climatic variability associated to the El Nino-Southern Oscillation (ENSO), possibly enhanced by anthropogenic climate change. A novel hybrid method combining the statistics of historical precipitation deficits with GCM mean projections provides estimates of future precipitation deficits. These findings suggest potential reductions in crop yields and hydropower capacity, which (although not quantitatively assessed in this study) are inferred based on the projected decline in water availability. Such impacts could lead to higher energy costs, increased reliance on fossil fuels, and intensified competition for water. Mitigation measures, including water-saving strategies, energy diversification, and integrated water resource management, are recommended to address these challenges. Full article

In this study, we analyzed the essential oils (EOs) extracted by steam distillation from the leaves and flowers of Parthenium hysterophorus L., grown in three different locations in southern Ecuador: Espíndola (ESP), Loja (LOJ) and Quilanga (QUI). Approximately 97.45%, 98.27% and 95.99% of the oil constituents were identified using gas chromatography–mass spectrometry (GC-MS) and gas chromatography–flame ionization detection (GC-FID). Sesquiterpene hydrocarbons were predominant in the EOs. The most representative constituents of the sample from ESP were germacrene D (35.08%), myrcene (11.32%), (E)-β-ocimene (10.21%), (E)-caryophyllene (7.90%), germacra-4(15),5,10(14)-trien-1-α-ol (5.18%) and (E, E)-α-farnesene (4.99%), with an AChE IC₅₀ of 14.78 and with 16.38 and 93.16 µg/mL from ABTS and DPPH, respectively. The EOs from LOJ were characterized by the abundant presence of germacrene D (28.30%), myrcene (13.95%), (E)-β-ocimene (10.51%) and isolongifolan-7-α-ol (8.26%), with an AChE IC₅₀ of 16.65 and with 36.18 and 158.43 µg/mL from ABTS and DPPH, respectively. Finally, the EOs from QUI contained germacrene D (32.20%), myrcene (13.36%), (E)-β-ocimene (8.54%), (E, E)-α-farnesene (6.77%), germacra-4(15),5,10(14)-trien-1-α-ol (5.69%) and (E)-caryophyllene (5.37%), with an AChE IC₅₀ of 10.69 and with 14.50 and 92.98 µg/mL from ABTS and DPPH, respectively. This study identifies chemotypic variation in P. hysterophorus collected from different locations and, for the first time, the AChE inhibitor was evaluated. These findings provide a scientific basis for the clinical application of P. hysterophorus EOs in the future treatment of Alzheimer’s disease. Full article

This study evaluated the pollutant removal efficiency of two decentralized wastewater treatment plants (WWTPs) located in the high-altitude southern Andes of Ecuador, Acchayacu and Churuguzo, from 2015 to 2024. Acchayacu previously operated using an upflow anaerobic filter (UAF), and from 2021, it transitioned to using vertical-subsurface-flow constructed wetlands (VSSF-CWs). In contrast, Churuguzo employs surface-flow constructed wetlands (SF-CWs). These systems were assessed based on parameters such as the five-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), total phosphorus, organic nitrogen, ammonia nitrogen, total solids, fecal coliforms (TTCs), and total coliforms (TCs). The data were divided into two subperiods to account for the change in technology in Acchayacu. Statistical analysis was conducted to determine whether significant differences existed between the treatment efficiencies of these technologies, and the SF-CW was found to consistently outperform both the UAF and VSSF-CW in removing organic matter and microbial pollutants. This difference is likely attributed to the longer hydraulic retention time, lower hydraulic loading rate, and vegetation type. The findings highlight the environmental implications of treatment technology selection in WWTPs, particularly regarding the quality of receiving water bodies and their potential applications for public health, proper water resource management, and the design of decentralized systems in high-altitude regions, especially in developing countries. Full article

This study aimed to (i) identify soil management practices implemented by farmers at the local level, (ii) determine the local soil fertility indicators recognized by farmers along an altitudinal gradient, (iii) evaluate the influence of altitude on soil properties, and (iv) integrate local and scientific knowledge of soil indicators and soil management. A total of 368 surveys were conducted to document traditional knowledge, visible indicators of soil fertility, and perceptions of soil health. These were compared with field-based measurements of soil organic carbon, texture, and environmental variables. A significant convergence was found between farmers’ perception of soil texture and scientific classification. A moderate correlation was observed between soil color and soil carbon stocks. Altitude showed a clear influence on carbon stocks, with soil at a higher elevation, characterized by greater rainfall and lower temperatures, storing more carbon. This integration of local and scientific knowledge offers practical value for farmers, extension agents, and institutions by supporting context-specific soil management decisions. It empowers farmers to actively participate in the design of sustainable agricultural practices that are both ecologically sound and culturally relevant. The study demonstrates that combining experiential knowledge with scientific data contributes to more resilient agroecosystems in mountainous rural areas. Full article

Ecuador, a tropical country with frequent dengue outbreaks, including a surge from 16,017 cases in 2022 to 61,329 in 2024, was the focus of this study. The study was conducted in Borbon, a semi-urban rural town in the Esmeraldas province. Genomic analysis, alongside entomo-virological surveillance, provides valuable insights into DENV-2 genotypes. Five pools of female Aedes aegypti mosquitoes from Borbon tested positive for DENV serotype 2 through RT-qPCR. One positive pool (CT = 16.13) was sequenced using Illumina MiSeq, and genotyping was conducted via the Dengue Typing Tool and Maximum Likelihood phylogenetic tree. The genotype assigned was III Southern Asian-American. Comparison with other genomes revealed genetic similarity to a human dengue genome sequenced in 2021, also from Esmeraldas, clustering with genomes reported across the Americas, particularly from Colombia and Venezuela. This study enhances our understanding of dengue virus epidemiology in rural areas, emphasizing the critical role of clinical case surveillance and vector monitoring in guiding evidence-based interventions. Full article

Energy development based on renewable energy has gained widespread acceptance in society, especially in recent years. Among the initiatives currently being promoted are those promoted by higher education institutions that utilize available space on their campuses by configuring energy systems to incorporate renewable generation technologies. This study conducts a techno-economic analysis of a hybrid energy system that combines photovoltaic systems, wind turbines, hydrokinetic turbines, batteries, and fuel generators for the Center for Research, Innovation, and Technology Transfer of the Universidad Católica de Cuenca (UCACUE) in southern Ecuador. Using data collected on site, particularly from the CIITT campus meteorological station and recorded on the RESMUCC platform, the size of each renewable system configuration is optimized based on the three proposed energy control algorithms. The designs of the different configurations developed using the Homer Pro tool are then compared in terms of costs and energy generated. The results show that the system, which includes photovoltaic systems, wind turbines, hydrokinetic turbines, and fuel-powered generators, has the lowest cost, at USD 0.33/kWh. Full article

We evaluated the global distribution of Anolis sagrei based on bibliographic records, GBIF, and iNaturalist data. Native to Cuba and the Bahamas, this lizard has spread across mainland America, particularly in the Caribbean, Central America, and parts of the U.S. It has also been introduced in Asia, and according to iNaturalist observations, it has been recorded in Israel, Canada, and northern South America. This species is especially abundant in the Caribbean and southeastern U.S., with high concentrations of records indicating a significant range expansion. In Ecuador, A. sagrei has been recorded along the coast and in the Amazon, with occurrences in Esmeraldas, Manabí, Guayas, Francisco de Orellana, and for the first time in Zamora Chinchipe (southern Amazon), specifically in El Pangui. The capture of 10 individuals confirmed their morphology, showing similarities with populations from Honduras and Cuba but differences in scalation and body size. In Ecuador, the fourth toe lamellae range from 29 to 33, consistent with those populations, while dorsal and ventral scales show variation (dorsal: 11–22, ventral: 10–25). Climate change favors its spread by enabling the colonization of new habitats. As an invasive species, it threatens local biodiversity, highlighting the need for monitoring and control in Amazonian Ecuador. An expanded abstract in Spanish is available, intended for local decision-makers. Full article

Tourism has proven to be highly vulnerable to external disruptions, particularly in communities with low levels of tourism development. In this context, this study examines residents’ attitudes towards tourism during the COVID-19 pandemic and assesses the impact of public and private initiatives in the Cajas Massif Biosphere Area (CMBA), located in southern Ecuador. Employing a mixed-methods approach, 825 surveys were conducted alongside 25 interviews with key sector stakeholders. The objective was to determine whether these attitudes reflect genuine resilience or merely a survival strategy in response to the crisis. The findings indicate that, despite some collective efforts and mitigation plans, the primary focus remained on short-term income preservation, while government policies prioritised tourism promotion over addressing structural needs, ultimately proving inadequate for tourism recovery. This scenario placed the burden of adaptation on residents, with expressions of solidarity that, however, diminished as the crisis subsided. This study concludes that reactive measures may be mistaken for genuine resilience, highlighting the need for comprehensive policies and more equitable stakeholder participation to strengthen social cohesion and ensure the viability of tourism in the face of future crises. Full article

Statistical cluster analysis applied to monthly 1–100 m ocean temperatures reveals El Niño–Southern Oscillation (ENSO) dipole patterns with a leading mode having opposing centers of action across the dateline and tropical east Pacific. We focus on the La Niña cold phase and study its impact on the Caribbean climate over the period of 1980–2024. East dipole time scores are used to identify composite years, and anomaly patterns are calculated for Jan-Jun and Jul-Dec. Convective responses over the Caribbean exhibit seasonal contrasts: dry winter–spring and wet summer–autumn. Trade winds and currents across the southern Caribbean weaken and lead to anomalous warming of upper ocean temperatures. Sustained coastal upwelling off Peru and Ecuador during east La Niña is teleconnected with easterly wind shear and tropical cyclogenesis over the Caribbean during summer, leading to costly impacts. This ocean–atmosphere coupling is quite different from the more common central Pacific ENSO dipole. Full article

The urgent need for sustainable strategies to mitigate climate change has spurred the development of efficient carbon sequestration methods with minimal greenhouse gas emissions, presenting promising opportunities to produce biochar and, with this bioproduct, enhance crop productivity. Therefore, this research aimed to evaluate the carbon footprint produced by the low-temperature slow pyrolysis of biomass obtained from the pruning residues of four tree species present in parks and gardens of the southern Andean region of Ecuador. An electric reactor (ER), powered by 44 solar panels of 535 W each, was used to perform the pyrolysis process at 350 °C over four hours. For each species—Persea americana, Polylepis spp., Acacia spp., and Prunus salicifolia—three replicates of the process were conducted using 1.5 kg of biomass per trial. The results showed that Acacia spp. residues produced biochar with higher bulk density (0.303 g/cm³), organic matter (82.85%), total organic carbon (71.21%), oxygen (27.84%), C/N ratio (120.69), and potassium (459.12 ppm). The biochar produced from Prunus salicifolia exhibited the highest levels of pollutant gas emissions and carbon footprint (5.93 × 10⁻⁶ ton∙m⁻³ CO₂ eq and 0.001067 ton∙m⁻³ CO₂ eq, respectively). In contrast, the biochar produced from Polylepis spp. was the least polluting (0.001018 ton∙m⁻³ CO₂ eq), highlighting its potential as a source for biochar production from tree species found in the southern Andean region of Ecuador. Meanwhile, the pyrolysis of Persea americana (avocado) resulted in very low gas emissions, although it exhibited the second-highest carbon footprint due to the high energy consumption associated with the process. In conclusion, this study identified Persea americana and Polylepis spp. as the best options for biochar production through pyrolysis, positioning them as viable alternatives for developing sustainable strategies to mitigate climate change. Full article

Background: Vitamin D deficiency is a significant risk factor for several chronic conditions. This study aims to predict vitamin D deficiency levels in a private database, collected from the southern part of Loja-Ecuador using a graphical web interface tool based on artificial intelligence algorithms. Methods: Two databases were processed using ML training models: SVM, Random Forest (RF), Linear Regression (LR). (i) Private data collection was undertaken on 465 patients from a local university, where vitamin D levels were measured through a blood sample collection to calculate the concentration of 25-hydroxy vitamin D in plasma and determine it by enzyme-linked immunosorbent assay, and (ii) public data collection was obtained from the FigShare database. Then, a survey was conducted from April 2022 to June 2023, identifying 157 variables, 18 of which were used for ML training models. Results: Vitamin D deficiency levels in private patients reached 18.10 ng/mL and 20.42 ng/mL in the public. The RF algorithm achieved (87.73%) accuracy, the SVM (80.0%), and LR (70.70%). RF was selected as the best performance model for web application design in binary levels classification: deficiency (Class 0) indicates vitamin D levels below 15 ng/mL, and sufficiency (Class 1) indicates vitamin D levels above 15 ng/mL. Conclusions: The “VITA-D” web application was used to monitor and predict vitamin D levels and deficiency factor risk based on clinical and sociodemographic data, providing an efficient and cost-effective alternative to traditional vitamin D testing methods. Full article

The aim of this study was to demonstrate the variability of essential oils (EOs) extracted from the culinary plant Plectranthus amboinicus in different locations, in order to determine their optimal utilization. The EO was extracted from fresh leaves by steam distillation at three locations in the south of Ecuador: Paccha (PAC), El Guabo (GUA), and Arenillas (ARE). Qualitative and quantitative analyses were performed by gas chromatography coupled with mass spectrometry (GC-MS) and flame ionization detection (GC-FID). A total of 41 compounds were identified in Paccha (97.37%), 38 compounds in Arenillas (97.43%), and 41 compounds in El Guabo (98.31%). The most abundant compounds identified were germacrene D (17.60%, 14.59%, and 12.85%), alfa humulene (10.88%, 4.65%, and 5.08%), alfa-terpinene (10.66%, 13.85%, and 6.79%), and carvacrol (5.11%, 5.97%, and 9.13%), in PAC, ARE, and GUA, respectively. In addition, the antioxidant activity was evaluated by ABTS and DPPH assays, as well as the total phenol content of the EOs. Finally, a principal compound analysis (PCA) was performed in order to evaluate the variation in compounds using the geographical location of the samples as a variable. Full article

The geological study area is volcano-tectonic in nature. Microscopic observations and mineralogical analyses revealed the presence of allophane and diatom clusters whose mineral compositions coincided with weathered andesites and dacites. Edometric consolidation tests showed a high porosity and a reduction in the void ratio by up to five times. These are highly compressible soils with a Cc/Cs ratio of 12 to 15 and a specific gravity (Gs) of 2.4. Low initial bulk density (1.10 Mg/m³), high plasticity, and SUCS (OH) classification are typical of soft soils, with an effective friction angle (ɸ’C_D) of 25.5° to 30° and effective cohesion (c’_CD) of 11.90 to 47.27 KPa. The shear wave velocity for the first 10 m (Vs10) on average ranged from 78 m/s to 120 m/s, whereas that for the first 30 m (Vs30) was 169 m/s. The permeability, which was calculated indirectly, was between 2 × 10⁻⁷ and 3 × 10⁻⁸ m/s. With an organic matter content between 5% and 25%, the Caupicho soil is an organic mineral sediment that is not considered peat (non-peat). The results of this study serve as a basis for future analyses of soil dynamics, bearing capacity, and consolidation settlements in the medium and long term in an area of high urban growth in southern Quito, Ecuador. Full article