Horizontes Amazónicos is a multidisciplinary, open-access, peer-reviewed scientific journal dedicated to the dissemination of original research on the Amazon region and analogous ecosystems. The journal advances knowledge across two main axes: exact and environmental sciences (agriculture, biotechnology, analytical chemistry, and ecology) and social sciences (education, identity, and sociocultural development). Its core mission is to build a rigorous bridge between technological innovation, natural capital conservation, and community progress, projecting territorial science into a global context.
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Mercury Exposure and Health Effects in Indigenous Communities of the Ecuadorian Amazon
Artisanal and small-scale gold mining (ASGM), consumption of methylmercury-contaminated fish and, to a lesser extent, deforestation of geogenic mercury-rich soils and oil extraction are the main sources of mercury (Hg) exposure in the Ecuadorian Amazon. This literature review synthesizes the available scientific evidence on exposure sources, human biomonitoring levels and health effects reported in Amazonian indigenous communities, focusing on Ecuadorian territory and comparing it with Brazil, Peru, Colombia and Bolivia. A scoping narrative review was conducted in PubMed/MEDLINE, Scopus, Web of Science, SciELO and LILACS, complemented with the Consensus academic search engine, covering 2000-2026 (with emphasis on 2015-2026), from which 28 peer-reviewed studies were included. Results show that Ecuadorian evidence on environmental exposure (water, sediment, fish) is relatively recent and growing, but human biomonitoring is essentially limited to two studies more than twenty years old (hair, 2004; urine, 2016), with no recent data on hair, blood or breast milk for any of the country's indigenous nationalities. In contrast, studies from Brazil, Peru, Colombia and Bolivia consistently document hair mercury concentrations above the World Health Organization threshold (6 µg/g) in indigenous populations, associated with neurocognitive impairment, peripheral neuropathy, hypertension and impaired child neurodevelopment. We conclude that mercury exposure risk among Ecuadorian Amazonian nationalities is probably underestimated due to the absence of updated human biomonitoring, despite a documented mining boom between 2018 and 2024, and propose a research agenda focused on hair methylmercury, child neurodevelopment and epidemiological surveillance with an intercultural approach.
Ingeniería Química, Biotecnología y Ambiental
Copyright (c) 2026 https://creativecommons.org/licenses/by/4.0
Sustainable innovation: Optimizing resources and reducing waste in the production of artisanal liquor in Pastaza
The production of artisanal liquor in the Ecuadorian Amazon represents a significant cultural and economic activity that faces environmental challenges due to the intensive use of water, energy, and waste generation. This study aimed to propose Cleaner Production (CP) strategies at the Puro-Puyo microenterprise, Pastaza, oriented toward optimizing resource use and reducing environmental impacts. Methodologically, diagnostic tools such as flow diagrams, ecomaps, mass and energy balances, and prioritization matrices were applied to identify critical points in the production process. The results showed that distillation and milling concentrate the main inefficiencies, highlighting the generation of vinasse (620 L/day), high water consumption (845 L/day), and diesel use (20 L/day). A package of technological improvements was proposed, including an anaerobic biodigester, bagasse composting, and a closed-loop cooling system, with a total investment of $2,300, an estimated annual economic benefit of $13,781, and a payback period of approximately two months. It is concluded that CP allows for the simultaneous improvement of environmental and economic performance, integrating sustainable innovation without affecting traditional knowledge and contributing to sustainable development in Amazonian contexts.
Ciencias Agropecuarias, Forestales y Agroindustriales
Copyright (c) 2026 Horizontes Amazónicos https://creativecommons.org/licenses/by/4.0
Evaluation of the antimicrobial effect of Uncaria tomentosa (Willd. ex Schult.) DC. extracts against bacterial and fungal strains of clinical and environmental importance
Antimicrobial resistance (AMR) is a growing global threat driving the search for plant-based therapeutic alternatives. Uncaria tomentosa (Willd. ex Schult.) DC. (cat's claw), an Amazonian liana of the Rubiaceae family, has a rich phytochemical composition with documented antimicrobial activity. We evaluated the antimicrobial effect of dry-bark extracts obtained with four solvents (EtOH 100%, MeOH 100%, EtOH 80:20, MeOH 80:20) at three concentrations (1%, 5%, 10% w/v) against Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538P, and Candida albicans ATCC 10231, using phytochemical screening, disk diffusion (Kirby-Bauer), and broth microdilution (MIC). Data were analyzed by multifactorial ANOVA with Tukey post hoc test. Screening confirmed alkaloids, flavonoids, tannins, phenols, saponins, and terpenoids in all extracts, with greater intensity in 80:20 mixtures. Inhibition zones were dose-dependent; MeOH 80:20 at 10% yielded the largest zones against S. aureus (19 mm) and C. albicans (18 mm). The lowest MIC (10 µg/mL) was obtained against S. aureus with MeOH 100%, MeOH 80:20, and EtOH 80:20. ANOVA revealed significant effects of solvent, concentration, microorganism, and interactions (p < 0.001–0.022). U. tomentosa is a promising source of natural antimicrobial agents, particularly effective against Gram-positive bacteria.
Copyright (c) 2026 Los autores https://creativecommons.org/licenses/by/4.0
Femicide and Media Representation: Critical Discourse Analysis of the Ximena Calvache Case in Pastaza Province, Ecuador
This research critically analyzes the media treatment of the femicide of Ximena Calvache, which occurred in Pastaza province, Ecuador, focusing on the narratives constructed by the digital outlet Portada TV and their impact on the social understanding of gender-based violence. The general objective was to examine the media coverage of this case, identifying the predominant narratives and their impact on social perception and institutional responses to femicide. Using a qualitative approach based on critical discourse analysis (CDA) and grounded in a feminist theoretical framework, the study examined the representations of the victim and the aggressor, the media construction of the events, the degree of compliance with the Organic Law to Prevent and Eradicate Violence against Women (LOIPEVCM), and the effects of this coverage on public opinion. The main unit of analysis was a news report published by Portada TV, complemented by an interview with the lawyer who represented the victim's family. The results show that the media treatment was marked by practices of revictimization, the reproduction of sexist stereotypes, the depersonalization of the victim, the pathologization of the aggressor, and a framing of the event as a "crime of passion", which depoliticized the femicide and presented it as an isolated incident, rendering its structural and systemic dimension invisible.
Sociedad, Identidad y Desarrollo Cultural
Nina Gualinga Sirén, Woman Whose Existence Is Resistance: An Analysis from Ecofeminism
The trajectory and struggles of Nina Gualinga Sirén, an Amazonian Kichwa woman, are analyzed from the perspective of Latin American ecofeminism. Through her life, two fundamental axes are articulated: the defense of Amazonian territory and the eradication of violence against indigenous women. Her leadership, the implications of the body-territory concept, and the role of Amazonian women's collectives in building community resistance are also examined. The analysis is grounded in a qualitative methodology based on academic sources, enabling an understanding of how Gualinga's struggles challenge both extractivism and patriarchy, contributing to reflection on female indigenous leadership and the urgent need to incorporate intersectional approaches in the defense of human rights and nature.
Water Quality in the Puyo River and Its Tributaries Based on Scientific Evidence and Challenges in Pastaza, Ecuador
A bibliographic review of research on water quality in the Puyo River and its tributaries was conducted, compiling studies from scientific databases and institutional repositories that report physicochemical, microbiological, and heavy metal parameters. Results indicate that the main sources of contamination are wastewater discharges, the presence of fecal coliforms, and the accumulation of heavy metals such as lead and mercury, associated with urban, agricultural, and mining activities. Community perception aligns with technical findings, as the majority of the population considers the water to be of poor quality and associates it with health problems. Over the past twenty years, a progressive deterioration in water quality parameters has been documented, with increases in turbidity and pathogenic microorganisms, despite some isolated recovery efforts. It is concluded that the lack of attention from the municipality and prefecture, together with the absence of continuous monitoring, worsens the water crisis, demanding a comprehensive management and participatory governance approach.
Quantification of Polyphenols in Moringa oleifera and Ruta graveolens with Different Solvents
The study was conducted to evaluate the total phenolic compound content in Moringa oleifera and Ruta graveolens, as well as the effect of different extraction solvents on their yield. The work responded to the need to explore plant sources of bioactive metabolites with antioxidant potential and applications in health and food. Leaves of both species were collected in the Puyo canton, Pastaza, Ecuador, and extracts were prepared using distilled water, 80% ethanol, and 80% methanol. Analyses were performed using the Folin-Ciocalteu method, applying a 1:50 prior dilution and spectrophotometric readings at 765 nm. Results showed that Moringa oleifera had a higher polyphenol content, reaching up to 587.73 mg GAE/g DM in methanol, while Ruta graveolens recorded more stable values, with a maximum of 415.08 mg GAE/g DM. It was concluded that the choice of solvent significantly influenced polyphenol extraction, confirming the potential of these species as natural sources of functional compounds.
Evaluation of the Antifungal Potential of Mansoa alliacea Extracts Against Phytopathogenic Fungi (Moniliophthora roreri and Rhizopus stolonifer) of Agricultural Interest
Leaf extracts of Mansoa alliacea, obtained by ultrasound-assisted extraction, exhibit potent antifungal activity against Moniliophthora roreri and Rhizopus stolonifer as a sustainable alternative to synthetic fungicides. Phytochemical screening revealed the presence of saponins, flavonoids, tannins, and free amino acids, and a clear dose-response relationship was observed: M. roreri proved highly susceptible, achieving complete inhibition (0 mm of mycelial growth) at concentrations of 70–80 mg/mL and significant reductions even at 15–50 mg/mL, while R. stolonifer showed greater resistance, with colony diameters progressively decreasing from 44 mm to 9 mm as extract concentration increased from 15 to 80 mg/mL. Multifactorial ANOVA analysis confirmed highly significant effects (p < 0.001) of extract concentration, fungal type, and their interaction, demonstrating that Mansoa alliacea constitutes a promising source of natural metabolites for the development of safe, effective, and environmentally friendly agricultural biocontrol agents.
Ichthyofauna Diversity as a Bioindicator of Water Quality, UEA Sucumbíos Campus Lagoon, Lago Agrio
This study was carried out at the lagoon of the Universidad Estatal Amazónica (UEA), located in Sucumbíos, with the objective of determining ichthyofauna diversity as bioindicators of water quality. Species richness and abundance were identified, diversity indices were calculated, and water quality was evaluated through physicochemical parameters, establishing a correlation with ichthyofauna diversity. Fish capture methods included baited pitfall traps, portable lift nets, and drag nets, complemented by water sampling for physicochemical analysis. A total of 138 individuals belonging to 4 orders, 4 families, and 4 species were identified, with no evident predominance among families, each represented by a single species. Pseudopoecilia festae was the most abundant, constituting 78.3% of the total, while Aequidens tetramerus was the least common at 2.7%. Diversity indices—Margalef (0.61), Shannon-Wiener (0.73), and Simpson (0.37)—indicated low ichthyofauna diversity with uniform distribution and no marked dominance. Regarding physicochemical parameters, significant differences were observed in pH, dissolved oxygen, and temperature. Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA) demonstrated that these variables influenced the presence and abundance of certain species, with some showing greater sensitivity to these conditions.
Biodiversidad, Ecología y Sostenibilidad
Learning Methodology and Academic Performance in the Social Sciences Subject
The objective of this research was to determine how learning methodology influences academic performance in the Social Sciences subject in Basic General Education, identifying factors associated with institutional results during the 2023–2024 period. The methodology consisted of a quantitative approach with a descriptive-correlational scope, using a non-experimental cross-sectional design, applied to a stratified sample of 150 students at intermediate, upper secondary, and baccalaureate levels. Survey techniques and documentary analysis of performance records were used, complemented by a systematic review of 15 specialized bibliographic sources from the 2021–2025 period. Results revealed that 64% of the student population shows insufficient performance, directly linked to the persistence of rote memorization methods that generate information overload. The Project-Based Learning approach was found to have a feasibility index of 88% for performance optimization, while the integration of recreational and digital resources significantly increases cognitive retention. It is concluded that low academic performance is reversible through the transition to systematic inquiry and contextualized didactic methodologies.
Female Leadership in the Sarayaku Community and Its Construction in the Amazonian Context
The case studied occurred in the Amazonian community of Sarayaku, in Ecuador, and addressed indigenous female leadership in a context traditionally dominated by patriarchal structures. The study focused on how Sarayaku women have managed to build and consolidate their leadership in the public and private spheres, overcoming cultural, social, and political barriers. It sought to document the forms of women's participation in the community, analyzing gender roles and changes in the internal social structure. An ethnographic approach was applied, with fieldwork and interviews with Sarayaku women leaders, allowing a deep understanding of local social and political dynamics. The main findings showed that female leadership emerged from a constant struggle for visibility and equity, with women being key in the defense of territory and culture. Despite difficulties, women found alternative spaces such as activism and community leadership. This experience highlights how indigenous women, historically marginalized, have become central actors in the defense of their rights and territory. It contributes to the study of indigenous movements and gender leadership, providing a model of empowerment and resistance.
Ecuador and the Paradox of Cheap Fuels That Ended Up Being Too Costly
This study analyzes the historical trajectory of fuel subsidies in Ecuador, from their establishment in 1974 to their partial and total elimination in 2024–2025 under the government of Daniel Noboa. Over five decades, this policy became entrenched as a measure socially perceived as a right, yet economically unsustainable, regressive, and a source of multiple distortions. Results show that the main beneficiaries were not vulnerable sectors, but rather middle and high-income households, heavy transport, and productive sectors, as well as illicit activities such as smuggling. The elimination of the diesel subsidy in 2025 frees up fiscal resources equivalent to 2–3% of GDP, strengthens debt sustainability, and reduces smuggling; however, it generates inflationary pressures on the basic food basket and risks of social conflict. The analysis highlights the dilemma between economic sustainability and political stability, concluding that the viability of the reform will depend on the state's capacity to target compensation, ensure transparency in resource use, and maintain social dialogue.
Urban Trees Under Hyperhumid Climate: Emerging Silvicultural Criteria for Urban Planning in the Ecuadorian Amazon
The study analyzed urban silviculture in hyperhumid climates, with emphasis on the Ecuadorian Amazon, aiming to establish emerging silvicultural criteria for urban tree planning. A narrative bibliographic review was employed, based on scientific literature published between 2010 and 2025, collected from academic databases and selected using criteria of thematic and geographic relevance. Analysis was conducted through thematic synthesis of the information. Results revealed that conditions of high precipitation, hydromorphic soils, and elevated phytosanitary pressure require differentiated approaches compared to conventional models. Five key criteria were identified: hydromorphic tolerance, phytosanitary resilience, adapted root management, ecological connectivity, and adaptation to flood dynamics. The importance of using native species for their greater adaptability and provision of ecosystem services was also highlighted. The study contributes technical guidelines for sustainable urban planning in understudied Amazonian contexts.
Spray-Drying Microencapsulation of Sacha Inchi Oil and Essential Oils of Eucalyptus, Lemon, and Basil
The oxidation of polyunsaturated fatty acids represents a critical limitation in the stability of vegetable oils, as their exposure to environmental conditions favors deterioration. In this context, the incorporation of natural antioxidants, such as essential oils, and the application of protective technologies, such as microencapsulation, constitute promising strategies for preserving quality and extending shelf life. The objective of this research was to microencapsulate sacha inchi oil in combination with eucalyptus, lemon, and basil essential oils using spray drying. A mixture of maltodextrin, gum arabic, and sacha inchi oil in a 1:1:1 ratio was used, incorporating essential oils at 0.5%, 0.4%, and 0.5%, respectively, with an inlet temperature of 150°C. Microcapsule formation was confirmed by FTIR-ATR spectrophotometry. Additionally, physical properties of the resulting powders were evaluated using the Carr and Hausner indices, yielding values above 38 and 1.6, indicating poor flowability and compressibility. Antioxidant capacity was determined by DPPH assay with dilutions of 1:200, 1:250, and 1:300, after dissolving 0.1 g of sample in 20, 25, and 30 mL of distilled water. Results demonstrated that the sacha inchi with lemon essential oil formulation exhibited the best antioxidant performance among all mixtures, recording a Carr index of 42.23, a Hausner index of 1.42, and an antioxidant capacity of 326.74 µmol/L Trolox equivalents. This study confirms the technical feasibility of the process for protecting Amazonian bioactive compounds and enhancing their commercialization potential.
Characterization of Wildlife Biodiversity in the Yanacocha Biopark
Biodiversity loss and illegal wildlife trafficking constitute critical threats to Ecuadorian Amazonian ecosystems, where rescue centers represent key spaces for the care, documentation, and conservation of species affected by human activities. This study aimed to characterize the wildlife biodiversity of the Yanacocha Biopark, located at kilometer 3.5 of the Puyo–Tena road, Pastaza Province, Ecuador, through systematic species recording, analysis of diversity indices, and identification of the main causes of animal intake. Four weekly direct observation visits were conducted during January 2026, complemented by a semi-structured interview with the biopark owner. A total of 48 species across five taxonomic groups were recorded: mammals (20 spp., 41.67%), birds (15 spp., 31.25%), reptiles (7 spp., 14.58%), fish (5 spp., 10.42%), and amphibians (3 spp., 6.25%). Calculated indices indicated high diversity (H' = 3.75), low dominance (d = 0.22), and equitable distribution among groups (J' = 0.97). Illegal trafficking constituted the main cause of intake (57.78%), followed by rescue due to injury or vulnerability (28.89%) and illegal domestic possession (13.33%). Results demonstrate that the Yanacocha Biopark plays a relevant role in the ethical care of affected wildlife and in environmental education, although its direct contribution to population conservation is limited, reinforcing the need to strengthen regulatory frameworks and systematic registration systems in Amazonian rescue centers.
Gamification in Mathematical Problem Solving and Mastery in High School Students
Low performance in solving mathematical problems in high school and the persistence of traditional methodologies motivated the validation of a gamification design. The objective was to assess the viability of a gamified proposal without implementing it, identifying potential problems, required resources, and estimated student engagement. A descriptive approach with piloting validation design was adopted. Participants included 120 students, 40 teachers, and 2 principals from two Ecuadorian educational institutions. Structured surveys and checklists were applied. Results indicated that 78% of students found the gamified components attractive, but 62% of classrooms lacked stable connectivity. A total of 92.5% of teachers required training in gamification. Expected engagement was high (mean 4.2/5), conditional on simplification of rules and competitive fairness. It is concluded that the design is viable provided adjustments are made in technological infrastructure, teacher training, and leveling mechanisms. Limitations and future directions are discussed.
Territory and Environmental Justice: Analysis of the Shuar Case in the Kutukú Shaimi Protected Forest (2024–2025)
The legal recognition of indigenous territories constitutes a pillar of environmental justice in Ecuador. Between 2024 and 2025, the State adjudicated 18,408 hectares within the Kutukú Shaimi Protected Forest (KSPF) to five Shuar communities (Pumpúas, Tayuntza Norte, Tunants, Kampan, and Tsuntsuim), directly benefiting more than 1,000 inhabitants, of whom approximately 50% are women. The process included 72 community assemblies and the development of Comprehensive Management Plans with zoning and conservation strategies. Results show advances in legal security, access to basic services, inclusion of female leadership, and forest restoration projects of at least 100 hectares. From an environmental perspective, the titling strengthens the conservation of more than 311,000 ha of megadiverse forest and contributes to national deforestation reduction targets. It is concluded that indigenous land ownership constitutes an effective tool for integrating social equity and ecological conservation in the Ecuadorian Amazon.