Urban rivers worldwide are increasingly exposed to multiple stressors from industrial, agricultural, and domestic activities; however, sensitive indicators to assess their ecological status remain limited. This study evaluated the potential of natural biofilms as bioindicators of environmental quality in two impacted river basins in Argentina: the Luján and Reconquista rivers. Biofilm and water samples were collected from upstream, urban, and industrial sites, and from controlled outdoor ponds used as a control. We analysed water physicochemical parameters, biofilm community composition, oxidative stress biomarkers (reduced glutathione, GSH; catalase, CAT; glutathione S-transferase, GST; and thiobarbituric acid reactive substances, TBARS), and extracellular enzyme activities (alkaline phosphatase, β-glucosidase). Results revealed clear water quality gradients, with downstream Luján sites and the mid-Reconquista showing severe deterioration, nutrient enrichment, hypoxia, and heavy metal exceedances. Biofilm communities mirrored these conditions: diverse and balanced assemblages dominated reference sites, while degraded ones showed reduced richness and tolerant taxa dominance. Biomarker responses also displayed consistent alterations, with high CAT activity (11,87 mmoles H2O2 cons x min−1 × mg prot−1 in L3 and 16,04 in R2), reduced GSH (0,007 mmoles GSH x g ww−1 in R2), and imbalances in GST and TBARS, indicating enhanced oxidative stress. Multivariate analyses integrated these datasets, consistently separating less-impacted from highly degraded sites. Overall, biofilms proved to be sensitive and cost-effective indicators, integrating structural and functional responses to contamination gradients, and offering a robust tool for monitoring urban rivers.
En las últimas décadas, diversas especies de vertebrados silvestres han incrementado su presencia en agroecosistemas, aprovechando recursos alimenticios y generando impactos negativos sobre la producción agrícola en Argentina. Aves y mamíferos muestran una elevada capacidad de adaptación a nuevos ambientes, con consecuencias productivas. Este estudio evaluó el daño ocasionado por la ardilla de vientre rojo y la cotorra en tres plantaciones de nuez pecán en Mercedes y una en Lobos (Buenos Aires) durante el otoño–invierno de 2023, considerando dos etapas fenológicas del cultivo: llenado del fruto y cosecha. La riqueza y abundancia de las ardillas de vientre rojo y cotorras se registraron mediante trampeo y conteos directos, identificándose a ambas especies como únicas responsables del daño. El tipo de daño se caracterizó a partir de rasgos morfológicos del consumo y se cuantificó mediante el porcentaje de frutos dañados, complementado con la estimación de biomasa perdida en kilogramos de nueces por planta. Los resultados indicaron que ambas especies generan pérdidas relevantes en la producción. Las ardillas consumieron principalmente la semilla durante la cosecha, con un porcentaje promedio de daño del 18,7 % (DS= 15,8), sin diferencias significativas en la magnitud del daño entre los lotes en los cuáles se registraron daños por esta especie (Kruskal–Wallis H= 0,22; p> 0,05). En contraste, las cotorras afectaron principalmente el llenado del fruto, dañando el ruezno y provocando caída prematura, con un 14,45 % (DS= 16,93) de daño, significativamente menor en Lobos (0,35 %; DS= 0,56; H= 15,74; p< 0,05). Las diferencias en la magnitud y el momento del daño evidencian estrategias de alimentación contrastantes entre ambas especies. Asimismo, la disponibilidad de frutos por planta se correlacionó positivamente con el daño registrado (Spearman: Rardillas= 0,85; p< 0,001; Rcotorras= 0,52; p< 0,05). Estos resultados resaltan la necesidad de implementar medidas de manejo específicas y ajustadas temporalmente, considerando la fenología del cultivo y la actividad de cada especie.
El artículo centra la mirada en la incorporación de la perspectiva de género en el ámbito del derecho ambiental internacional en relación, específicamente, con el derecho humano de acceso al agua potable. Desde un enfoque cualitativo y a través del análisis documental de instrumentos ambientales elaborados por organismos internacionales, se examinaron los avances y vacíos legales existentes en relación con los principios de igualdad e interseccionalidad. Los resultados del trabajo permiten observar que, aunque la comunidad internacional ha reconocido progresivamente la centralidad del acceso al agua como derecho humano, la dimensión de género continúa siendo marginal. Por lo que se concluye que la incorporación efectiva de este enfoque es indispensable para garantizar la equidad, la sostenibilidad y el cumplimiento de los compromisos internacionales en materia de derechos humanos y ambiente y que también es atravesado por la realidad del cambio climático.
Despite the frequent co-occurrence of glyphosate and arsenic in agricultural freshwater systems, the biochemical mechanisms underlying their combined toxicity in fish remain poorly understood. Here, we evaluated the acute (96 h) individual and joint effects of glyphosate (0.5 mg/L) and arsenic [As(III), 0.5 mg/L] on the Neotropical fish Cnesterodon decemmaculatus using an integrated biomarker approach. Endpoints related to oxidative balance, DNA integrity, neurotoxicity, and energy metabolism were assessed across multiple tissues. Glyphosate exposure induced marked oxidative and metabolic disturbances, including increased catalase activity, glutathione levels, and mitochondrial electron transport system activity, along with reduced cellular energy allocation and glutathione-S-transferase activity. In contrast, arsenic decreased glutathione content, superoxide dismutase activity, lipids, and carbohydrates. Comparable DNA damage levels were observed across single and combined exposures. Co-exposure resulted in non-additive interactions, with mixture effects deviating from the sum of individual responses, leading to either reduced (antagonistic) or enhanced (potentiation) effects depending on the biomarker and its direction of change. Antagonistic interactions predominated for genotoxic and several oxidative stress biomarkers, whereas potentiation was observed for selected metabolic endpoints. Multivariate analysis revealed distinct physiological profiles among treatments, with partial overlap between glyphosate and mixture responses. These findings underscore the complexity of pollutant mixture effects and highlight the need to incorporate combined exposures into ecotoxicological risk assessment.
Mapping wetlands is essential for conservation, but their dynamic nature makes them difficult to detect, especially drier-end types. These challenges are amplified in urban and peri-urban areas, where wetlands are small, fragmented, and frequently under-represented in inventories. Furthermore, many mapping efforts lack the methodological transparency required for replicability and adaptation. This study addresses these gaps by presenting a novel, replicable, and cost-effective methodological framework for mapping complex wetlands. The approach is structured as a hierarchical workflow that leverages open data and computational resources. It integrates multi-temporal optical, SAR, and LiDAR-derived features within Google Earth Engine to generate a time-series of annual Land Use/Land Cover (LULC) classifications. This is followed by a post-processing workflow that produces a final filtered Wetlands map, a LULC map (mode), and a Frequency map, allowing for a nuanced understanding of wetland dynamics. We developed and evaluated this framework in the Metropolitan area of Buenos Aires, Argentina, a landscape where such wetlands are often overlooked. The framework successfully delineated multiple wetland classes (Ponds, Wet meadows, Artificial wetlands and Rivers) from non-wetland classes. The final Wetlands map was evaluated using 372 independent points with an overall accuracy of 0.91 (95% CI: [0.87, 0.94]), estimated from the population error matrix to provide unbiased accuracy and area estimates. The primary contribution is the transparent methodological framework itself. All scripts are openly shared to facilitate full replication and adaptation, providing environmental managers a robust tool for inventorying and monitoring challenging wetland systems.
