Instituto Regional de Estudios en Sustancias Tóxicas (IRET)

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14395

Instituto Regional de Estudios en Sustancias Tóxicas (IRET-UNA) es un centro de investigación con proyección nacional, regional e internacional, comprometido con el desarrollo sostenible, la protección y conservación de los ecosistemas naturales, la calidad de vida de los trabajadores y de la sociedad afectados por las sustancias tóxicas y otras actividades humanas.

Los conocimientos y datos generados por el Instituto son utilizados por entidades gubernamentales y no gubernamentales como fuente primaria de información en temas de exposición a las sustancias tóxicas y sus efectos en el ambiente y en la salud humana.

Contáctenos:

Página web: www.iret.una.ac.cr

Correo: iret@una.ac.cr

Teléfono: (506) 2277-3584 / (506) 2277-3587

Programas adscritos a IRET-UNA

El Programa Infantes y Salud Ambiental (ISA) es un programa de investigación-extensión realizado en la región Huetar Atlántica, Costa Rica, que utiliza un enfoque eco-sistémico en salud humana (EcoSalud). Estudiamos la exposición ambiental a plaguicidas y manganeso y sus efectos sobre la salud de niño(a)s y sus madres. Además, estudiamos cuáles factores explican las exposiciones a plaguicidas, y posibles alternativas para su uso. Promovemos acciones colaborativas para reducir el contacto con plaguicidas y mitigar sus posibles efectos.

El Programa ISA tiene 3 áreas temáticas: 1) Contexto socio- económico, cultural y percepción de riesgos, 2) Evaluación de exposición y efectos en el crecimiento y desarrollo de infantes y 3) Alternativas agro-ecológicas.

Coordinadora: Ph.D. Berna van Wendel de Joode, correo electrónico: berendina.vanwendel.dejoode@una.cr

Contacto:

Página web: www.isa.una.ac.cr

Correo: programaisa@una.ac.cr

Teléfono: (506) 2562-3678 / (506) 2562-3671

El Programa Salud, Trabajo y Ambiente (SALTRA) se proyecta como un programa estratégico en la integración de principios de desarrollo sostenible en las políticas de salud ocupacional y ambiental a nivel local, nacional y regional desde la gestión del conocimiento: docencia, investigación extensión y traducción política. Se trabaja en Centroamérica para consolidar y extender una estructura regional de centros universitarios en salud ocupacional y ambiental (SOA) que colaboren entre sí y con grupos gubernamentales y no gubernamentales, para conjuntamente construir capacidades locales, nacionales y regionales que favorecen la incorporación de principios de desarrollo sostenible en las políticas de salud ocupacional y ambiental.

Coordinadora regional: Ph. D. Jennifer Crowe, correo electrónico: jennifer.crowe@una.cr

Contacto:

Página web: www.saltra.una.ac.cr

Correo: saltraregional@una.cr

Teléfono: (506) 2263 6375

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Mostrando 1 - 11 de 11

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.
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.
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.
Ecological and Public Health Effects of Microplastics Pollution
(Emerging Contaminants and Associated Treatment Technologies, 2022) Rojas Jimenez, Keilor; Arias Andres, Maria
Humans and ecosystems are constantly exposed to microplastics (MP). The magnitude of contamination, their ubiquity, and high persistence over time raise serious concerns about their effects on ecosystems, wildlife, and human health. MP represent a diverse class of contaminants occurring on a continuum of sizes and in various shapes and presenting a complex composition that includes several types of polymers and several associated pollutants. In short, MP are perhaps one of the most challenging contaminants created by humankind. The effects of exposure to these pollutants are of growing concern even though the type and level of exposure and the specific risks for humans and ecosystem health have not yet been entirely determined. In this chapter, we identify critical qualitative and quantitative aspects of MP sources and exposure routes and toxicity profiles and confront them with research on MP effects and estimations of risks to human and environmental health. Finally, we highlight that some novel sources of MP contamination pose a serious risk of exposure to humans and ecosystems, such as nanoplastics and the recycled plastics incorporated into road pavements and construction.
Effects of the insecticide β-endosulfan on tadpoles of Isthmohyla pseudopuma (Anura: Hylidae)
(Elsevier, 2022) Méndez Rivera, Michael.; Mena, Freylan; Pinnock Branford, Margaret; Ruepert, Clemens; Barquero, Marco D.; Jiménez, Randall R.; Alvarado, Gilbert
Conventional agriculture uses pesticides intensively. Once pesticides are released into the environment, they can be toxic to non-target organisms. Exposure of amphibians to pesticides can be lethal and affect their growth, development and behavior. β-endosulfan is a persistent organochlorine that has been detected in environmental samples within protected sites in Costa Rica, far from agricultural areas. The aim of this study was to evaluate the lethal and sublethal effects, as well as changes in three biomarkers (Cholinesterase activity [ChE], glutathione S- transferase activity [GST] and lipid peroxidation [LPO]) in tadpoles of Isthmohyla pseudopuma exposed to β-endosulfan. A 96-h acute test (20, 40, 60, 80, 100 and 200 µg/L) was performed in order to calculate the median lethal concentration (LC 50 ), while effects on growth and development were assessed during a 4-weeks chronic test (10, 20, 30 and 50 µg/L). In addition, we measured the aforementioned biomarkers in tadpoles exposed to concentrations below the LC 50 . The 96-h LC 50 for this species was 123.6 µg/L. We found no evidence of β-endosulfan influencing any of the three biomarkers evaluated. At 50 µg/L, both length and total weight of tadpoles decreased with respect to the control. Also, at 30 and 50 µg/L we observed that individuals showed a slower development. Therefore, we demonstrated that at sublethal concentrations, β-endosulfan negatively affects I. pseudopuma at early stages causing tadpoles to develop slower and smaller than normal.
Influence of Seasonality and Pollution on the Presence of Antibiotic Resistance Genes and Potentially Pathogenic Bacteria in a Tropical Urban River
(Universidad Nacional, Costa Rica, 2025-08-05) Barrantes-Jiménez, Kenia; Mendoza-Guido, Bradd; Morales-Mora, Eric; Rivera-Montero, Luis; Montiel-Mora, Jose; Chacón-Jiménez, Luz; Rojas-Jiménez, Keilor; Arias-Andrés, Maria
Background/Objectives: This study examines how seasonality, pollution, and sample type (water and sediment) influence the presence and distribution of antibiotic resistance genes (ARGs), with a focus on antibiotic resistance genes (ARGs) located on plasmids (the complete set of plasmid-derived sequences, including ARGs) in a tropical urban river. Methods: Samples were collected from three sites along a pollution gradient in the Virilla River, Costa Rica, during three seasonal campaigns (wet 2021, dry 2022, and wet 2022). ARGs in water and sediment were quantified by qPCR, and metagenomic sequencing was applied to analyze chromosomal and plasmid-associated resistance profiles in sediments. Tobit and linear regression models, along with multivariate ordination, were used to assess spatial and seasonal trends. Results: During the wet season of 2021, the abundance of antibiotic resistance genes (ARGs) such as sul-1, intI-1, and tetA in water samples decreased significantly, likely due to dilution, while intI-1 and tetQ increased in sediments, suggesting particle-bound accumulation. In the wet season 2022, intI-1 remained low in water, qnrS increased, and sediments showed significant increases in tetQ, tetA, and qnrS, along with decreases in sul-1 and sul-2. Metagenomic analysis revealed spatial differences in plasmid-associated ARGs, with the highest abundance at the most polluted site (Site 3). Bacterial taxa also showed spatial differences, with greater plasmidome diversity and a higher representation of potential pathogens in the most contaminated site. Conclusions: Seasonality and pollution gradients jointly shape ARG dynamics in this tropical river. Plasmid-mediated resistance responds rapidly to environmental change and is enriched at polluted sites, while sediments serve as long-term reservoirs. These findings support the use of plasmid-based monitoring for antimicrobial resistance surveillance in aquatic systems.
Parental Occupational Exposure to Pesticides and the Risk of Childhood Leukemia in Costa Rica
(Scand J Work Environ Health, 2007-08-31) Monge, P; Wesseling, Catharina; Guardado, J; Lundberg, Ingvar; Ahlbom, Anders; Cantor, Kenneth P; Weiderpass, Elisabete; Partanen, Timo
Parental exposure to pesticides and the risk of leukemia in offspring were examined in a population based case–control study in Costa Rica. All cases of childhood leukemia (N=334), in 1995–2000, were identified at the Cancer Registry and the Children’s Hospital. Population controls (N=579) were drawn from the National Birth Registry. Interviews of parents were conducted using conventional and icon-based calendar forms. An exposure model was constructed for 25 pesticides in five time periods. Mothers’ exposures to any pesticides during the year before conception and during the first and second trimesters were associated with the risk [odds ratio (OR) 2.4, 95% confidence interval (95% CI) 1.0–5.9; OR 22, 95% CI 2.8–171.5; OR 4.5, 95% CI 1.4–14.7, respectively] and during anytime (OR 2.2, 95% CI 1.0–4.8). An association was found for fathers’ exposures to any pesticides during the second trimester (OR 1.5, 95% CI 1.0–2.3). An increased risk with respect to organophosphates was found for mothers during the first trimester (OR 3.5, 95% CI 1.0–12.2) and for fathers during the year before conception and the first trimester (OR 1.5, 95% CI 1.0–2.2 and OR 1.6, 95% CI 1.0–2.6, respectively), and benzimidazoles during the first, second, and third trimesters of pregnancy (OR 2.2, 95% CI 1.0–4.4; OR 2.2, 95% CI 1.0–5.0; OR 2.2, 95% CI 1.0–5.2, respectively). There was a suggestion of an exposure–response gradient for fathers as regards picloram, benomyl, and paraquat. Age at diagnosis was positively associated with fathers’ exposures and inversely associated with mothers’ exposures. The results suggest that parental exposure to certain pesticides may increase the risk of leukemia in offspring.
Seasonal dynamics and pesticide impact on gut microbiome in Amynthas gracilis earthworms: A comparative study across agricultural landscapes assessed by 16S rRNA amplicon-based sequencing
(Elsevier, 2025-08-27) Brenes-Bravo, Gabriel; Solano-Campos, Frank; Ruepert, Clemens; Mena, Freylan
The use of pesticides in agriculture can affect the biodiversity of soil ecosystems and interfere with the ecological services they provide. The gut microbiome of earthworms serves as a bioindicator for changes in diversity within one of the most representative groups of soil macrofauna. In this study, we defined a gradient of soil and pesticide use regimes within a horticultural area, including conventional management, good agricultural practices, organic production and forest. Earthworms (A. gracilis) from these four conditions were sampled, and their microbiomes were assessed by sequencing the V4 region from the 16S rRNA gene. Comparison of ASVs indicated the presence of 142 bacterial genera among all the samples, with Actinobacteriota, Proteobacteria, Firmicutes and Bacteroidota being dominant phyla. Simpson’s diversity index revealed diminished biodiversity in the gut microbiomes of earthworms from conventionally managed soil, correlating negatively with the presence of the insecticide chlorpyrifos. Furthermore, a seasonal shift in the dominance of bacterial taxa was observed between dry and rainy seasons. These shifts were evident in the gut microbiome of organisms from organically managed and good practices soils but not in the conventional site. Our results demonstrate that earthworm’s gut microbiome serves as a responsive bioindicator for biodiversity changes in agricultural landscapes, suggesting that key features of the microbial community can be altered by pesticide exposure.
Short-term exposure to benzalkonium chloride in bacteria from activated sludge alters the community diversity and the antibiotic resistance profile
(IWA PUBLISHING, 2021) Chacón, Luz.; Arias-Andrés, Maria; Mena, Freylan; Rivera, Luis.; Hernández, Lorena; Achi, Rosario; Garcia, Fernando.; Rojas-Jiménez, Keilor.
La introducción continua de productos de limpieza que contienen cloruro de benzalconio (BAC) procedente de vertidos domésticos puede moldear las comunidades microbianas de las plantas de tratamiento de aguas residuales (EDAR) de una forma aún poco conocida. En este estudio, realizamos una exposición in vitro de lodos activados de una EDAR de Costa Rica a BAC, cuantificamos los cambios en los perfiles génicos intI1, sul2 y qacE/qacEΔ1, y determinamos alteraciones en la composición de la comunidad bacteriana. El análisis de los datos de qPCR reveló elevadas cargas de genes de resistencia a antibióticos en la comunidad microbiana; tras la exposición a BAC se observó un aumento significativo del gen qacE/qacEΔ1, relacionado con la resistencia al cuaternario de amonio. El análisis de las secuencias del gen 16S rRNA mostró variaciones pronunciadas en la estructura de las comunidades bacterianas, incluyendo una reducción de los valores de diversidad alfa y un aumento de la abundancia relativa de Alphaproteobacteria, particularmente de Rhodospseudomonas y Rhodobacter. Confirmamos que las comunidades microbianas presentaban una alta resiliencia al BAC en la concentración de mg/mL, probablemente debido a la exposición constante a este contaminante. También presentaron genes relacionados con la resistencia a antibióticos con mecanismos similares para tolerar esta sustancia. Estos mecanismos deberían explorarse más a fondo, especialmente en el contexto de un elevado uso de desinfectante.
The fungicide chlorothalonil changes the amphibian skin microbiome: a potential factor disrupting a host disease-protective trait
(MDPI, 2021-04-08) Jiménez, Randall R.; Alvarado, Gilbert; Ruepert, Clemens; Ballestero, Erick.; Sommer, Simone
The skin microbiome is an important part of amphibian immune defenses and protects against pathogens such as the chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis. Alteration of the microbiome by anthropogenic factors, like pesticides, can impact this protective trait, disrupting its functionality. Chlorothalonil is a widely used fungicide that has been recognized as having an impact on amphibians, but so far, no studies have investigated its effects on amphibian microbial communities. In the present study, we used the amphibian Lithobates vibicarius from the montane forest of Costa Rica, which now appears to persist despite ongoing Bd-exposure, as an experimental model organism. We used 16S rRNA amplicon sequencing to investigate the effect of chlorothalonil on tadpoles’ skin microbiome. We found that exposure to chlorothalonil changes bacterial community composition, with more significant changes at a higher concentration. We also found that a larger number of bacteria were reduced on tadpoles’ skin when exposed to the higher concentration of chlorothalonil. We detected four presumed Bd-inhibitory bacteria being suppressed on tadpoles exposed to the fungicide. Our results suggest that exposure to a widely used fungicide could be impacting host-associated bacterial communities, potentially disrupting an amphibian protective trait against pathogens.
The Impact of Urban Pollution on Plasmid-Mediated Resistance Acquisition in Enterobacteria from a Tropical River
(Universidad Nacional, Costa Rica, 2024-11-14) Mendoza Guido, Bradd; Arias Andres, Maria; Barrantes, Kenia; Rodrıguez, Cesar; Rojas-Jimenez, Keilor
The exposure of environmental bacteria to contaminants in aquatic ecosystems accelerates the dissemination of antibiotic-resistance genes (ARGs) through horizontal gene transfer (HGT). In this study, we sampled three locations along a contamination gradient of a polluted river, focusing on isolating Enterobacteria from the surface waters to investigate the relationship between urban pollution and antibiotic resistance. The genomes of 15 isolates (5 per site) were sequenced to identify plasmid-borne ARGs and their association with resistance phenotypes. Results: Isolates from the site with the highest contamination (Site 3) showeda larger number of ARGs, plasmids, and resistance phenotypes. Notably, one of the isolates analyzed, E. coli A231-12, exhibited phenotypic resistance to seven antibiotics, presumably conferred by a single plasmid carrying 12 ARGs. Comparative analysis of this plasmid revealed its close evolutionary relationship with another IncH plasmid hosted by Salmonella enterica, underscoring its high ARG burden in the aquatic environment. Other plasmids identified in our isolates carried sul and dfrA genes, conferring resistance to trimethoprim/sulfamethoxazole, a commonly prescribed antibiotic combination in clinical settings. These results highlight the critical need to expand research on the link between pollution and plasmid-mediated antimicrobial resistance in aquatic ecosystems, which can act as reservoirs of ARGs.

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