Artículos científicos

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A biogeochemical comparison of three representative lakes of Costa Rica
(INLAND WATERS (Taylor and Francis), 2025-01-09) Esquivel-Hernández, Germain; Sánchez-Gutiérrez, Rolando; Arias Andrés, María.; Ugalde-Salazar, Rocío; Echeverría- Sáenz, Silvia
Lakes are widely distributed across Costa Rica, from coasts to the highest elevation regions and located in the main terrestrial biomes, yet updated biogeochemical information about the main types of lakes is still lacking. We present comparative biogeochemistry (water chemistry, stable isotopes, and picoplankton) for a coastal lake (Lake Madre de Dios), a volcanic lake (Lake Barva), and a glacial lake (Lake Ditkevi). Sampling was conducted between February and November 2022, including dry and rainy seasonal conditions. Hydrological and chemical conditions were evaluated using water and carbon stable isotopes, dissolved organic matter, major ions, and microbiota analysis. Isotopic data on water (δ2H and δ18O) and dissolved inorganic carbon (δ13CDIC) confirmed lower evaporative losses for the maar and tarn lakes and productivity response to precipitation inputs. Excitation/emission matrices confirmed the prevalence of fulvic and humic acids in the coastal and glacial lakes, mainly aromatic proteins and soluble microbial byproducts in the volcanic lake. Picophytoplankton (PPP, ∼0.2–10 μm) was mainly represented by phycocyanin-rich picocyanobacteria in the 3 lakes, but maar and tarn lakes had greater representation of phycoerythrin-rich picocyanobacteria. We confirmed fluctuations in PPP cell abundance in the lakes was lower than in comparable temperate lakes. For other eutrophic lakes, abundance of picocyanobacteria dominated over picoeukaryotic algae. This work aimed to promote an ecosystem approach to study the biogeochemical functioning of tropical lakes using a combination of chemical, hydrological, and biological data and to provide baseline information for future studies (e.g., climate change and pollution impacts) on tropical lakes of Costa Rica.
A case study on pharmaceutical residues and antimicrobial resistance genes in Costa Rican rivers : a possible route of contamination for feline and other species
(Elsevier, 2023-11-12) Vargas-Villalobos, Seiling; Hernández, Felix; Fabregat-Safont, David; Salas-González, Denis; Quesada-Alvarado, Francisco; Botero-Coy, Ana Maria; Esperón, Fernando; Martín-Maldonado, Bárbara; Monrós-González, Juan; Ruepert, Clemens; Estrada-König, Sandra; Rivera-Castillo, Josué; Chaverri-Fonseca, Fabio; Blanco-Peña, Kinndle
In this investigation, the presence of antibiotics and pharmaceuticals in Costa Rican surface waters, specifically in regions near feline habitats, was examined. The study revealed that 47% of the water samples contained detectable traces of at least one antibiotic. Ciprofloxacin and norfloxacin were the most frequently detected compounds, each with a detection rate of 27%. Other antibiotics, such as erythromycin, roxithromycin, and trimethoprim, were also found but at lower frequencies, around 14%. Notably, all antibiotic concentrations remained below 10 ng/L, with ciprofloxacin, norfloxacin, and erythromycin showing the highest concentrations. Furthermore, the investigation revealed the presence of non-antibiotic pharmaceutical residues in the water samples, typically at concentrations below 64 ng/L. Tramadol was the most frequently detected compound, present in 18% of the samples. The highest concentrations were observed for acetaminophen and tramadol, measuring 64 and 10 ng/L, respectively. Comparing these findings with studies conducted in treated wastewater and urban rivers, it became evident that the concentrations of antibiotics and pharmaceuticals were notably lower in this study. While previous research reported higher values, the limited number of studies conducted in protected areas raises concerns about the potential environmental impact on biodiversity. In summary, these results emphasize the importance of monitoring pharmaceutical residues and antimicrobial resistance genes ARGs in vulnerable ecosystems, especially those in close proximity to feline habitats in Costa Rica. Additionally, the study delved into the detection of (ARGs). All tested water samples were positive for at least one ARG, with the blaTEM gene being the most prevalent at 82%, followed by tetS at 64% and qnrB at 23%. Moreover, this research shed light on the complexity of evaluating ARGs in environmental samples, as their presence does not necessarily indicate their expression. It also highlighted the potential for co-selection and coregulation of ARGs, showcasing the intricate behaviors of these genes in aquatic environments.
A multidisciplinary approach to analyze the antimicrobial resistance in natural ecosystems
(Elsevier, 2024-02-25) Blanco-Pena, Kinndle; Quesada-Alvarado, Francisco; Salas-González, Denis; Estrada- König, Sandra; Salom-Pérez, Roberto; Arroyo-Arce, Stephanny; Villalobos-Araya, Adriana; Rivera-Castillo, Josué; Martín-Maldonado, Bárbara; Corrales-Gutiérrez, Daniel; Gallardo-Castro, Valeria; Gutiérrez-Espeleta, Gustavo; Chaves, Andrea; Esperón, Fernando; Chaverri-Fonseca, Fabio
Antimicrobial Resistance (AMR) poses a global threat to both human health and environmental well-being. Our study delved into Costa Rican wildlife reserves, uncovering a substantial human impact on these ecosystems and underscoring the imperative to pinpoint AMR hotspots. Embracing a One Health perspective, we advocated for a comprehensive landscape analysis that intricately intertwined geographic, climatic, forest, and human factors. This study illuminated the link between laboratory results and observed patterns of antimicrobial use, thereby paving the way for sustainable solutions. Our innovative methodology involved deploying open-ended questions to explore antimicrobial usage across livestock activities, contributing to establishing a comprehensive methodology. Non-invasive sampling in wildlife emerged as a critical aspect, shedding light on areas contaminated by AMR. Feline species, positioned at the apex of the food chain, acted as sentinels for environmental health due to heightened exposure to improperly disposed waste. Regarding laboratory findings, each sample revealed the presence of at least one antimicrobial resistance gene (ARG). Notably, genes encoding resistance to tetracyclines dominated (94.9%), followed by beta-lactams (75.6%), sulfonamides (53.8%), aminoglycosides (51.3%), quinolones (44.9%), phenicols (25.6%), and macrolides (20.5%). Genes encoding polymyxins were not detected. Moreover, 66% of samples carried a multi-resistant microbiome, with 15% exhibiting resistance to three antimicrobial families and 51% to four. The absence of a correlation between forest coverage and ARG presence underscored the profound human impact on wildlife reserves, surpassing previous estimations. This environmental pressure could potentially modify microbiomes and resistomes in unknown ways. As not all antimicrobial families encoding ARGs were utilized by farmers, our next step involved evaluating other human activities to identify the primary sources of contamination. This comprehensive study contributed crucial insights into the intricate dynamics of AMR in natural ecosystems, paving the way for targeted interventions and sustainable coexistence.
Acute toxicity and cholinesterase inhibition of the nematicide ethoprophos in larvae of gar Atractosteus tropicus (Semionotiformes: Lepisosteidae)
(Universidad Nacional, Costa Rica, 2011) Mena Torres, Freylan; Pfennig, Sascha; Arias Andrés, María de Jesús; Márquez Couturier, Gabriel; Sevilla, Adrián; Protti, Maurizio
Biomarkers are a widely applied approach in environmental studies. Analyses of cholinesterase (ChE), glutathione S-transferase (GST) and lipid peroxidation (LPO) are biomarkers that can provide information regarding early effects of pollutants at different biochemical levels on an organism. The aim of this study was to evaluate the biomarker approach on a Costa Rican native and relevant species. For this, larvae of gar (Atractosteus tropicus) were exposed to the organophosphorus nematicide, ethoprophos. Acute (96hr) exposure was conducted with pesticide concentrations ranging from 0.1µg/L to 1 500µg/L. The 96hr LC50 calculated was 859.7µg/L. After exposure, three biomarkers (ChE, GST and LPO) were analyzed in fish that survived the acute test. The lowest observed effect concentration (LOEC) regarding ChE activity inhibition was 50µg/L. This concentration produced a significant inhibition (p<0.05) of the enzyme by 20%. The highest concentration tested without showing any effect on ChE activity and therefore considered as no observed effect concentration (NOEC) was 10µg/L. Ethoprophos concentration of 400µg/L caused a ChE inhibition by 79%. In this study, no significant variations (p>0.05) in GST activity and LPO were observed in A. tropicus larvae after exposure to ethoprophos.
Agriculture without paraquat is feasible without loss of productivity lessons learned from phasing out a highly hazardous herbicide
(Springer Nature Link, 2023-01-09) Ramírez-Muñoz, Fernando; Sánchez U., Jorge.; Stuart, Alexander M; Merfield, Charles N; Horgan, Finbarr G; Willis, Sheila; Watts, Meriel A.; Sánchez U., Jorge ; Utyasheva, Leah; Eddleston, Michael ; Davis, Mark L; Neumeister, Lars ; Sanou, Manoé R.; Williamson, Stephanie
A small proportion of the thousands of pesticides on the market today are associated with a disproportionately high incidence of severe acute pesticide poisoning and suicide. Paraquat stands out as one of the most lethal pesticides in common use, frequently involved in fatal incidents due to suicides or accidental exposure. Even though paraquat has been banned in over 67 countries, it is still widely used in many others, particularly in Asia and Latin America. Based on a literature review and consultations, this paper identifes options for replacing paraquat and distils practical lessons from numerous successes around the world. Our aim is to support regulators, policymakers, agronomists and the supply chain sector with practical information related to phasing out paraquat. Production data consistently failed to show any negative efects of banning paraquat on agricultural productivity. A wide range of alternative approaches to weed management and crop defoliation are available, many of which do not rely on herbicides. Over 1.25 million farmers in low- and middle-income countries (LMICs) successfully produce a range of crops for private voluntary standards (PVS) in food and fber supply chains which prohibit paraquat use. We conclude from the fndings of this study that eliminating paraquat will save lives without reducing agri- cultural productivity. Less hazardous and more sustainable alternatives exist. To enhance successful adoption and uptake of these methods on a wide scale, farmers require training and support within an enabling policy environment.
Aislamiento, identificación y caracterización de cepas bacterianas con potencial de degradación de los plaguicidas clorotalonil y clorpirifos
(Universidad Nacional, Costa Rica, 2023) Estrada Gamboa, Joyce María; Umaña Castro, Rodolfo; Sancho Blanco, Carolina; Orozco Aceves, Martha
El uso indiscriminado de plaguicidas altamente tóxicos en la agricultura ha producido contaminación de los suelos y deterioro de los ecosistemas. Una solución prometedora para este problema ambiental es la biorremediación, que incluye el uso de bacterias para degradar sustancias contaminantes, incluidos los plaguicidas. [Objetivo] El presente trabajo tuvo por objetivo el aislamiento, identificación y caracterización de cepas bacterianas con capacidad de degradar los plaguicidas clorotalonil y clorpirifos, para su potencial uso en la biorremediación de suelos contaminados. [Metodología] Las cepas fueron aisladas de suelos agrícolas mediante cultivos de enriquecimiento, que contenían clorotalonil o clorpirifos (20 mg/L) como única fuente de carbono. Las cepas aisladas se caracterizaron por su morfología, fisiológicamente por su respuesta a 48 pruebas bioquímicas y frente a 15 antibióticos, cinética de crecimiento, y molecularmente (amplificación del gen 16S). [Resultados] Se aisló una cepa bacteriana capaz de utilizar (y degradar) clorpirifos como fuente de carbono, identificada como Stenotrophomonas maltophilia y dos cepas bacterianas con capacidad parcial de utilizar clorotalonil como fuente de carbono, identificadas como Enterobacter cloacae y Ochrobactrum anthropi. Las tres especies bacterianas son bacilos Gram negativo y presentaron características fisiológicas diversas, incluyendo resistencia variable a ciertos antibióticos. [Conclusión] Se concluye que las bacterias aisladas tienen potencial biotecnológico para ser incorporadas en una estrategia de biorremediación de suelos contaminados, especialmente para eliminación de clorpirifos. Finalmente, se plantean perspectivas de investigación a futuro para dilucidar procesos más eficientes de degradación de clorotalonil mediante cometabolismo.
Anthropogenic imprint on riverine plasmidome diversity and proliferation of antibiotic resistance genes following pollution and urbanization
(Universidad Nacional, Costa Rica, 2025-03-24) Barrantes-Jiménez, Kenia ; Lejzerowicz, Franck; Tran, Tam; Calderón-Osorno, Melany; Rivera-Montero, Luis; Rodríguez-Sánchez, César; Wikmark, Odd-Gunnar; Eiler, Alexander; Grossart, Hans-Peter; Arias-Andrés, María; Rojas-Jiménez, Keilor
Plasmids are key determinants in microbial ecology and evolution, facilitating the dissemination of adaptive traits and antibiotic resistance genes (ARGs). Although the molecular mechanisms governing plasmid replication, maintenance, and transfer have been extensively studied, the specific impacts of urbanization-induced pollution on plasmid ecology, diversity, and associated ARGs in tropical regions remain underexplored. This study investigates these dynamics in a tropical aquatic ecosystem, providing novel insights into how pollution shapes plasmid composition and function. In contrast to the observed decrease in chromosomal diversity, we demonstrate that pollution associated with urbanization increases the diversity and taxonomic composition of plasmids within a bacterial community (plasmidome). We analyzed eighteen water and sediment metagenomes, capturing a gradient of pollution and ARG contamination along a tropical urban river. Plasmid and chromosomal diversity profiles were found to be anti-correlated. Plasmid species enrichment along the pollution gradient led to significant compositional differences in water samples, where differentially abundant species suggest plasmid maintenance within specific taxonomic classes. Additionally, the diversity and abundance of ARGs related to the plasmidome increased concomitantly with the intensity of fecal and chemical pollution. These findings highlight the critical need for targeted plasmidome studies to better understand plasmids' environmental spread, as their dynamics are independent of chromosomal patterns. This research is crucial for understanding the consequences of bacterial evolution, particularly in the context of environmental and public health.
Asociación entre la exposición ambiental a plaguicidas y cáncer en Costa Rica para los últimos 35 años
(Universidad Nacional, Costa Rica, 2021) Santamaría Ulloa, Carolina.; Ortiz, Adolfo.; Ramírez, Fernando.; Salas, Denis.; Mora, A.; Montero López, Melina.; Gutiérrez, F.
Esta investigación tiene como objetivo determinar si existe en Costa Rica una asociación entre la exposición ambiental a plaguicidas y la incidencia de cáncer y su sobrevida en los últimos 35 años. En una primera etapa exploraremos todas las localizaciones anatómicas de cáncer según grandes grupos funcionales. Posteriormente nos centraremos en cáncer de mama, próstata, ovario y aquellas otras localizaciones que hayan mostrado asociaciones significativas en la etapa exploratoria previa. Las principales fuentes de información serán: Registro Nacional de Tumores (Ministerio de Salud), Estadísticas Vitales, Proyecciones Oficiales de Población y Censo Nacional Agropecuario 1984 y 2014 (Instituto Nacional de Estadística y Censos) y Boletines Estadísticos Agropecuarios (Ministerio de Agricultura y Ganadería). La metodología consiste en la utilización de técnicas de análisis espacio-temporal y Sistemas de Información Geográfica para determinar si existe una asociación entre la exposición ambiental a plaguicidas y la incidencia de cáncer, así como entre sta exposición y la sobrevida de los pacientes luego de su primer diagnóstico. La estimación de tasas de incidencia de cáncer se hará a nivel de distrito según quinquenio. Se estimará un índice de exposición ambiental a plaguicidas a partir de datos de los Censos Agropecuarios del INEC y de los Boletines Estadísticos agropecuarios del MAG. Mediante análisis de regresión espacial se determinará la magnitud de la asociación. El alcance de esta investigación es informar la política sanitaria en temas de exposición a plaguicidas y cáncer.
Associations between pesticide mixtures applied near home during pregnancy and early childhood with adolescent behavioral and emotional problems in the CHAMACOS study
(ENVIRONMENTAL EPIDEMIOLOGY, 2021) Hyland, Carly; Bradshaw, Patrick T.; Gunier, Robert; Mora, Ana M.; Kogut, Katherine; Deardorff, Julianna; Sagiv, Sharon; Bradman, Asa; Eskenazi, Brenda
Evidence from longitudinal cohort studies indicates that biomarkers of pesticide exposure and residential proximity to agricultural pesticide applications during pregnancy and early childhood may be associated with adverse child neurodevelopment, including poorer cognition1–6 and increased hyperactivity/ inattention7–9 and traits related to autism spectrum disorders.10–13 Despite relatively consistent findings for outcomes assessed during early and middle childhood, previous studies have only followed children up to the age of 12 years, and data gaps exist regarding the persistence of pesticide–neurodevelopment associations into adolescence and young adulthood.
Bacterial communities in residential wastewater treatmentplants are physiologically adapted to high concentrations of quaternary ammonium compounds
(Wiley Online Library, 2023-08-28) Chacón, Luz; Rojas-Jimenez, Keilor; Arias-Andres, Maria
Benzalkoniumchloride(BAC)isaquaternaryammoniumcompound(QAC)widely used as the active ingredient of disinfectants. Its excessive discharge into wastewater is constant and in high concentrations, likely affecting the physiology of microbial communities. We compared the physiological community profile of activated sludge (AS) bacteria with and without prior in vitro exposure to a high concentration of BAC(10 mg L−1). We measured the community functional diversity, carbon substrate multifunctionality, and the median effective concentration thatinhibits carbon respiration (EC50) using Biolog EcoPlates supplemented with a gradient of 0–50 mg L−1 of BAC. Surprisingly, we did not find significant differences in the physiological parameters among treatments. Certain abundant bacteria, including Pseudomonas, could explain the community’s tolerance to high concentrations of BAC. We suggest that bacterial communities in wastewater treatment plants’ AS are “naturally” adapted to BAC due to frequent and high-dose exposure. We highlight the need to understand better the effects of QACs in wastewater, their impact on the selection of tolerant groups, and the alteration in community metabolic profiles.
Benchmarking AI-based Plasmid Annotation Tools for Antibiotic Resistance Genes Mining From Metagenome of the Virilla River, Costa Rica
(Universidad Nacional, Costa Rica, 2023-11-28) Rojas-Villalta, Dorian; Calderón-Osorno, Melany; Barrantes, Kenia; Arias-Andres, Maria; Rojas-Jiménez, Keilor
Bioinformatics and Artificial Intelligence (AI) stand as rapidly evolving tools that have facilitated the annotation of mobile genetic elements (MGEs), enabling the prediction of health risk factors in polluted environments, such as antibiotic resistance genes (ARGs). This study aims to assess the performance of four AI-based plasmid annotation tools (Plasflow, Platon, RFPlasmid, and PlasForest) by employing defined performance parameters for the identification of ARGs in the metagenome of one sediment sample obtained from the Virilla River, Costa Rica. We extracted and sequenced complete DNA from the sample, assembled the metagenome, and then performed the plasmid prediction with each bioinformatic tool, and the ARGs annotation using the Resistance Gene Identifier web portal. Sensitivity, specificity, precision, negative predictive value, accuracy, and F1-score were calculated for each ARGs prediction result of the evaluated plasmidomes. Notably, Platon emerged as the highest performer among the assessed tools, exhibiting exceptional scores. Conversely, Plasflow seems to face difficulties distinguishing between chromosomal and plasmid sequences, while PlasForest has encountered limitations when handling small contigs. RFPlasmid displayed diminished specificity and was outperformed by its taxon-dependent workflow. We recommend the adoption of Platon as the preferred bioinformatic tool for resistome investigations in the taxon-independent environmental metagenomic domain. Meanwhile, RFPlasmid presents a compelling choice for taxon-dependent prediction due to its exclusive incorporation of this approach. We expect that the results of this study serve as a guiding resource in selecting AI-based tools for accurately predicting the plasmidome and its associated genes.
Cambios en la superficie sembrada de palma aceitera en el cantón de Osa, Puntarenas. Período 2014-2018
(Universidad Nacional, Costa Rica, 2020-06-29) Salas Gonzáles, Denis Mauricio
El cultivo de palma aceitera muestra un acelerado crecimiento a nivel mundial. Según datos oficiales, solo en la región latinoamericana se evidencia un crecimiento del 150,8% en el área cultivada de palma de aceite al pasar de 443 000 hectáreas en 2001 a 1 111 000 hectáreas sembradas en 2014, de las cuales 818 000 se encontraban en etapa productiva aportando cerca del 6% del aceite de palma producido en el mundo (González, 2016). Estas plantaciones han impactado los paisajes tropicales por la disminución de la vegetación natural, pastos o por el reemplazo de otros cultivos. La expansión del cultivo de palma de aceite aumentó en Costa Rica y de acuerdo con la tendencia de los últimos años, seguirá en aumento. En los últimos años se han realizado censos y encuestas agropecuarias que muestran el crecimiento general, pero no detallan las áreas geográficas donde se da ese crecimiento y el consecuente impacto a la dinámica natural de las áreas cultivadas, información clave para los procesos de ordenamiento territorial regional y local que tenemos en el país. Por tal motivo, los objetivos de esta investigación fueron: analizar el cambio en la superficie sembrada con palma aceitera en el cantón de Osa, provincia de Puntarenas en el periodo 2014-2018 y evaluar la expansión del cultivo de palma aceitera en los distritos del cantón. Para esto, se analizaron datos de instituciones gubernamentales y se identificaron y digitalizaron las plantaciones de palma aceitera de los seis distritos del cantón de Osa.
Contributions of the academy for a better understanding of the oceans in Costa Rica
(Ministerio de Relaciones Exteriores y Culto, 2024-03) Morales-Ramírez, Álvaro; Gómez-Ramírez, Eddy; Alfaro-Martínez, Eric; Hidalgo, Hugo G.; Ulate-Naranjo, Karol; Arias-Andres, Maria; Rojas-Villalobos, Fresia; Samper-Villarreal, Jimena; Wehrtmann, Ingo S.
El lanzamiento de la Década de los Océanos en el año 2017 estableció nuevas visiones entre la ciencia y política, para fortalecer la investigación y la gestión de los océanos y las costas. Con un 92% de superficie marina, Costa Rica es una nación de mar, que posee una gran diversidad marina, y que realiza esfuerzos para conocer mejor sus recursos costeros y marinos. En los últimos 20 años, se han desarrollado políticas para promover la gestión integrada de nuestras zonas costeras y la creación de áreas marinas protegidas. Mediante la investigación de las universidades públicas, conocemos mejor, aunque de manera incompleta, cómo se encuentran nuestros recursos pesqueros y acuicultura, los impactos de la contaminación marina y sus efectos sobre organismos y ecosistemas, los impactos del cambio climático, así como los esfuerzos para impulsar la conservación marina y la restauración de los ecosistemas marino-costeros y sus servicios. Del análisis de estas áreas de estudios, es evidente, que existen vacíos de información que deben ser abordados para generar más información científica que permita la toma de decisiones adecuadas y basadas en la ciencia, con el objeto de mejorar las políticas púbicas relacionadas a las zonas costeras, sus recursos, los servicios ecosistémicos, la gestión de las numerosas fuentes de contaminación continental que llegan a la costa y la adaptación al cambio climático.
Dissimilar behavioral and spatial avoidance responses by shrimps from tropical and temperate environments exposed to copper
(Springer, 2022-11-17) Redondo López, Sergei; González Ortegón, Enrique.; Mena, Freylan; Araújo, Cristiano
Behavioral changes associated with exposure to pollutants represent the earliest response for organisms confronted by perceivable chemical signals. This study was carried out with the objective of evaluating behavioral responses associated with different scenarios of exposure to pollutants (non-forced vs forced) in two shrimp species (Penaeus vannamei and Palaemon varians), representative of different latitudes and using copper as a model contaminant. The effects on locomotion were evaluated by exposing the shrimps to a range of copper concentrations (0, 0.5, 5, 50, and 250 µg/L) in the forced scenario. After exposure, the movement patterns for each shrimp were recorded and used to estimate changes in the shrimps’ locomotion. For the non-forced scenario, the avoidance response was assessed by placing shrimps in a multi-compartment system where they were able to move freely along a gradient of copper (0, 0.5, 5, 50, and 250 µg/L). In terms of locomotion, an opposite trend was observed between the species: movements were significantly reduced in P. varians with concentrations above 50 µg/L, while hyperactivity was observed for P. vannamei. When exposed to a gradient of copper in the multi-compartment system, both species significantly avoided the highest concentrations of copper, although the repellence of copper was stronger for P. vannamei. In summary, both species of shrimps were able to recognize and avoid copper; however, in terms of locomotion, they showed an opposite behavioral reaction. These results show that a contamination event can have different behavioral outcomes depending on the species and complementing forced and non-forced exposure with species-specific information can be helpful to characterize and predict the effects of contaminants at higher biological levels.
Early Toxic Effects in a Central American Native Fish (Parachromis dovii) Exposed to Chlorpyrifos and Difenoconazole
(Society of Environmental Toxicology and Chemistry, 2021-03-18) Jiménez, Katherine; Solano, Karla; Scholz, Carola; Redondo López, Sergei; Mena, Freylan
In Costa Rica, agriculture is one of the most important economic activities. Chlorpyrifos and difenoconazole have been identified as agrochemicals widely used in banana and pineapple crops in the Caribbean area of the country and are constantly recorded in aquatic ecosystems. The toxicity of these pesticides in Parachromis dovii was studied. Median lethal concentrations (LC50s) for each substance were obtained from 96‐h acute tests. Then, fish were exposed to sublethal concentrations of both substances (10% of LC50), individually and in mixture, to evaluate biomarker responses. Ethoxyresorufin‐O‐deethylase (EROD), catalase, and glutathione S‐transferase activities as well as lipid peroxidation were measured in liver and gill tissues as markers of biotransformation and oxidative stress processes. Cholinesterase activity in brain and muscle tissue was also quantified as a biomarker of toxicity. The LC50s were 55.34 μg/L (95% confidence interval [CI] 51.06–59.98) for chlorpyrifos and 3250 μg/L (95% CI 2770–3810) for difenoconazole. Regarding the biomarkers, a significant inhibition of brain and muscle cholinesterase activity was recorded in fish exposed to 5.50 μg/L of chlorpyrifos. This activity was not affected when fish were exposed to the mixture of chlorpyrifos with difenoconazole. Significant changes in lactate dehydrogenase activity were observed in fish exposed to 325 μg/L of difenoconazole, whereas fish exposed to th mixture showed a significant increase in EROD activity in the liver. These results suggest harmful effects of chlorpyrifos insecticide at environmentally relevant concentrations. There is also evidence for an interaction of the 2 substances that affects the biotransformation metabolism at sublethal levels of exposure.
Ecological consequences when organisms avoid a contaminated environment: a study evaluating the toxicity of fipronil
(Elsevier B.V., 2024-03-03) Moreira, Raquel A.; González, María Pilar; Dias, Mariana A.; Ogura, Allan P.; Mena, Freylan; Montagner, Cassiana C.; Espíndola, Evaldo L. G.; Blasco, Julián; Parra, Gema; Araújo, Cristiano V. M.
The ability of aquatic organisms to sense the surrounding environment chemically and interpret these signals correctly is crucial to their survival and ecological niche. This study applied the Heterogenous Multi-Habitat Assay System - HeMHAS to evaluate the avoidance potential of Daphnia magna to detect fipronil-contaminated habitats in a connected landscape after a short (48 h), previous, forced exposure to an environmentally relevant concentration of the same insecticide. The swimming of daphnids was also analyzed by recording the total distance covered. D. magna preferred areas with less contamination, although the effect of fipronil on their swimming ability (a decrease) was observed for all the concentrations tested. The application of non-forced multi-compartment exposure methodologies is a recent trend and is ecologically relevant as it is based on how contamination can really produce changes in an organism's habitat selection. Finally, we consider the importance of more non-forced exposure approaches where Stress Ecology can be aggregated to improve systemic understanding of the risk that contaminants pose to aquatic ecosystems from a broader landscape perspective.
El impacto de la resistencia a los antibióticos en el desarrollo sostenible
(Universidad de Costa Rica, 2022) Barrantes, Kenia.; Chacon Jimenez, Luz; Arias Andrés, María
La resistencia a los antimicrobianos (RAM) es un problema de salud pública cada vez más complejo y se considera como una de las mayores amenazas en todo el mundo. El desarrollo de la RA en los patógenos bacterianos es una consecuencia esperada de la adaptación evolutiva, debido a la presencia de este tipo de contaminantes, los antibióticos, en variedad de nichos ecológicos. Además, hay múltiples factores asociados con su origen y diseminación, entre ellos, el uso desmedido y poco regulado de los antibióticos en la medicina humana y veterinaria, así como en la agricultura, la ganadería y la industria. De hecho, recientemente se ha indicado el papel del ambiente como reservorio para genes de RA y bacterias resistentes a antibióticos. En este sentido, el enfoque para contener y controlar este problema tan complejo involucra de forma necesaria a diversas áreas como la medicina, la veterinaria, las ciencias ambientales y sectores de la industria y la economía. En este artículo, se realiza una descripción tanto del problema de la RA y sus elementos causales, como del enfoque multidisciplinario que ha sido propuesto para su manejo en el ámbito global. Se detalla también cómo la RA afecta el desarrollo humano sostenible conforme a la Agenda 2030 formulada por la ONU, en el cumplimiento de algunos de los objetivos del desarrollo sostenible (ODS).
Evaluación preliminar del área agrícola y su influencia sobre la calidad del agua en el Golfo Dulce, Costa Rica
(Universidad Nacional, Costa Rica., 2019) Fournier, María Luisa; Castillo, Luisa E.; Ramírez-Muñoz, Fernando; Moraga López, Geannina; Ruepert, Clemens
Se realizó una evaluación preliminar de la agricultura en las subcuencas Esquinas, Coto Colorado, Rincón, Conte, Agujas, Tigre y Palma, como criterio base para el diseño de un plan de seguimiento de la calidad del agua que ingresa al estuario. Se determinó el área de los cultivos, mediante interpretación de imágenes satelitales, para un total aproximado de 10 000 ha de arroz Oryza sativa y 31 000 ha de palma aceitera Elaeis guineensis. El uso de agroquímicos se estimó con base en información secundaria publicada y con encuestas administradas a grupos productores. El uso anual estimado de plaguicidas fue de 20.4 kg ha-1 en arroz y 6.6 kg ha-1 en palma, y 840 kg ha-1 año-1 de fertilizantes granulados en ambos cultivos. Asimismo, se hizo un muestreo puntual de residuos de plaguicidas en agua, sedimento y peces, analizados con cromatografía de gases acoplada a espectrometría de masas y cromatografía de líquidos con detector de arreglo de diodos. En todas las muestras de agua se detectó el herbicida clomazone. Además, en la subcuenca Coto Colorado, la cual abarca el 95 % del total del área agrícola que drena al golfo, se detectó el insecticida triazofos y los fungicidas isoprotiolano y propiconazol. La extensión y el manejo de las plantaciones agrícolas en la cuenca del Golfo Dulce, aunada a factores ambientales, podría representar una amenaza sobre los recursos del estuario. Por ello, se recomienda monitorear la calidad del agua en los ríos, así como iniciar programas de restauración de los bosques de ribera como medida de mitigación.
Exposure to an environmentally relevant concentration of chlorpyrifos induces transcriptional changes and neurotoxicity in Poecilia gillii without clear behavioral effects
(Elsevier, 2025-02-12) Sánchez-González, Daniel; Blanco Peña, Kinndle; Solano-Campos, Frank; Solano Díaz, Karla; Mena Torres, Freylan Gerardo
Overusing chlorpyrifos (CPF) in tropical countries such as Costa Rica poses a potential risk to freshwater ecosystems. This study investigated the effects of transient exposure to an environmentally relevant CPF concentration on the native fish species Poecilia gillii, employing a comprehensive approach that evaluated multiple levels of biological organization. Using RT-qPCR, we quantified transcript changes in genes involved in various biological processes, including inflammation and apoptosis; annexin A1 (anxa1b), cytokine regulation; cytokine-inducible SH2-containing protein (cish), redox reactions; NADH oxidoreductase subunit A2 (ndufa2), protein translocation; Sec61 gamma subunit (sec61g), and biotransformation; glutathione S-transferase rho (gstr). Additionally, we measured biochemical biomarkers such as phase I; 7-ethoxyresorufin-O-deethylase (EROD) and phase II; glutathione S-transferase (GST) biotransformation enzymes, oxidative stress markers; catalase (CAT) and lipid peroxidation (LPO), and conducted behavioral tests to assess swimming fitness and antipredator reactions. Neurotoxicity was assessed by measuring brain and muscle tissue cholinesterase (ChE) activity. Following 48 h of exposure to 5.5 µg/L CPF, we observed significant downregulation of the sec61g and gstr genes, decreased CAT activity, and neurotoxic effects, as indicated by reduced ChE activity in muscle. Although no significant behavioral changes were detected, our results suggest that short-term exposure to environmentally relevant CPF concentrations can disrupt gene expression, compromising biotransformation and protein synthesis in P. gillii juveniles. Moreover, the observed neurotoxicity, which is consistent with the mechanism of action of CPF, may lead to subtle behavioral changes. This study provides evidence of the sublethal effects of CPF on nontarget organisms, highlighting the importance of considering gene expression changes when assessing CPF toxicity.
Exposure to pesticides and health effects on farm owners and workers from conventional and organic agricultural farms in Costa Rica : Protocol for a cross-sectional study
(JMIR Publications, 2019-01-25) Fuhrimann, Samuel; Winkler, Mirko S.; Staudacher, Philipp; Weiss, Frederik T.; Stamm, Christian; Eggen, Rik IL; Lindh,Christian H; Menezes-Filho, José A; Baker, Joseph M; Ramírez-Muñoz, Fernando; Gutiérrez-Vargas, Randall; Mora, Ana M
Background: Pesticide use is increasing in low- and middle-income countries (LMICs) including Costa Rica. This increase poses health risks to farm owners, farm workers, and communities living near agricultural farms. Objective: We aimed to examine the health effects associated with occupational pesticide exposure in farm owners and workers from conventional and organic smallholder farms in Costa Rica. Methods: We conducted a cross-sectional study involving 300 owners and workers from organic and conventional horticultural smallholder farms in Zarcero County, Costa Rica. During the baseline study visit, we administered a structured, tablet-based questionnaire to collect data on sociodemographic characteristics, pesticide exposure, and health conditions (eg, respiratory and allergic outcomes and acute pesticide intoxication symptoms) and administered a neurobehavioral test battery (eg, Finger Tapping Test and Purdue Pegboard); we measured blood pressure, anthropometry (height, weight, and waist circumference), and erythrocytic acetylcholinesterase activity and also collected urine samples. In addition, a functional neuroimaging assessment using near-infrared spectroscopy was conducted with a subset of 50 study participants. During the follow-up study visit (~2-4 weeks after the baseline), we administered participants a short questionnaire on recent pesticide exposure and farming practices and collected hair, toenail, and urine samples. Urine samples will be analyzed for various pesticide metabolites, whereas toenails and hair will be analyzed for manganese (Mn), a biomarker of exposure to Mn-containing fungicides. Self-reported pesticide exposure data will be used to develop exposure intensity scores using an exposure algorithm. Furthermore, exposure-outcome associations will be examined using linear and logistic mixed-effects regression models. Results: Fieldwork for our study was conducted between May 2016 and August 2016. In total, 113 farm owners and 187 workers from 9 organic and 83 conventional horticultural smallholder farms were enrolled. Data analyses are ongoing and expected to be published between 2019 and 2020. Conclusions: This study is one of the first to examine differences in health effects due to pesticide exposure between farm owners and workers from organic and conventional smallholder farms in an LMIC. We expect that this study will provide critical data on farming practices, exposure pathways, and how occupational exposure to pesticides may affect farm owners and workers’ health. Finally, we hope that this study will allow us to identify strategies to reduce pesticide exposure in farm owners and workers and will potentially lay the groundwork for a future longitudinal study of health outcomes in farm owners and workers exposed to pesticides.

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