Efecto de la exposición a glifosato y ciprofloxacina en bacterias entéricas de renacuajos

La alta carga de agroquímicos y antibióticos en los ambientes acuáticos y los agroecosistemas representa un riesgo para la vida silvestre. Dado que la microbiota intestinal juega un papel fundamental en el funcionamiento de su hospedador y es sensible a una amplia variedad de contaminantes, su estudio permite evaluar la salud de los organismos. En este trabajo estudiamos los efectos de formulaciones comerciales de un herbicida a base de glifosato (GBH) y del antibiótico ciprofloxacina (CIP), por separado y en mezcla, sobre la diversidad de bacterias intestinales de renacuajos del sapo común (Rhinella arenarum). El estudio de la diversidad de bacterias entéricas cultivables de rápido crecimiento y bajo requerimiento nutricional se llevó a cabo utilizando pruebas microbiológicas clásicas e identificación por espectrometría de masas de tiempo de vuelo por desorción/ionización láser asistida por matriz (MALDI-TOF). La microbiota entérica fue diferente según el tratamiento. El GBH indujo un aumento de la diversidad bacteriana, mientras que la CIP produjo una reducción. Entre estos cambios, destaca la presencia de Yersinia spp. y Proteus spp. solo en el tratamiento con GBH. Además, en el tratamiento GBH-CIP se encontró una disminución en la prevalencia de Klebsiella spp. y Pseudomonas spp. en la microbiota intestinal de los renacuajos. Este es el primer informe sobre la alteración del contenido bacteriano intestinal de renacuajos de R. arenarum producido por dos contaminantes emergentes de preocupación. Demostramos que el renacuajo del sapo común se puede utilizar como un organismo modelo no convencional para el monitoreo de la contaminación ambiental. Estos hallazgos constituyen el primer paso para comprender cómo la presencia de GBH y CIP en aguas dulces puede representar una amenaza para la vida silvestre y la salud humana a través de la disbiosis entérica asociada al efecto sobre la comunidad bacteriana.The high load of agrochemicals and antibiotics present in agricultural aquatic environments represents a risk for wildlife. Since enteric bacteria, which play a key role in the physiological functioning of their hosts, are sensitive to a wide variety of pollutants, their study allows to evaluate the health of organisms. This study aimed to evaluate the effects of commercial formulations of a glyphosate-based herbicide (GBH) and the antibiotic ciprofloxacin (CIP), individually and in mixture, on the bacterial diversity of the intestinal content of common toad (Rhinella arenarum) tadpoles. The diversity of cultivable fast-growing bacteria with low nutritional requirements was evaluated using classic microbiological tests and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry identification. Bacterial diversity varied among treatments. Taxa diversity increased in the GBH-treated group but decreased in the CIP-treated group. Remarkably, Yersinia spp. and Proteus spp. were only found in the GBH-treated group. The prevalence of Klebsiella spp. and Pseudomonas spp. decreased in the intestinal microbiota of the GBH-CIP-treated group. To our knowledge, this is the first report on the alteration of cultivable enteric bacteria of autochthonous tadpoles due to two pollutants of emerging concern. Our results demonstrate that R. arenarum tadpoles can be used as non-conventional model organisms for environmental pollution monitoring. Our preliminary findings would contribute to understanding how the presence of GBH and CIP in freshwaters may represent a threat to wildlife and human health by causing enteric dysbiosis of part of the bacterial community.Fil: Cuzziol Boccioni, Ana Paula. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: García Effron, Guillermo. Universidad Nacional del Litoral; ArgentinaFil: Peltzer, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; ArgentinaFil: Lajmanovich, Rafael Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; Argentin

Risk of chlorine dioxide as emerging contaminant during SARS-CoV-2 pandemic: enzyme, cardiac, and behavior effects on amphibian tadpoles

Objective The use of chlorine dioxide (ClO2) increased in the last year to prevent SARS-CoV-2 infection due to its use as disinfectant and therapeutic human treatments against viral infections. The absence of toxicological studies and sanitary regulation of this contaminant represents a serious threat to human and environmental health worldwide. The aim of this study was to evaluate the acute toxicity and sublethal efects of ClO2 on tadpoles of Trachycephalus typhonius, which is a common bioindicator species of contamination from aquatic ecosystems. Materials and methods Median lethal concentration (LC50), the lowest-observed efect concentration (LOEC), and the noobserved efect concentration (NOEC) were performed. Acetylcholinesterase (AChE) and glutathione-S-transferase (GST) activities, swimming behavior parameters, and cardiac rhythm were estimated on tadpoles of concentrations≤LOEC exposed at 24 and 96 h. ANOVA and Dunnett’s post-hoc comparisons were performed to defne treatments signifcance (p≤0.05). Results The LC50 of ClO2 was 4.17 mg L−1 (confdence limits: 3.73–4.66). In addition, NOEC and LOEC values were 1.56 and 3.12 mg L−1 ClO2, respectively, at 48 h. AChE and GST activities, swimming parameters, and heart rates increased in sublethal exposure of ClO2 (0.78–1.56 mg L−1) at 24 h. However, both enzyme activities and swimming parameters decreased, whereas heart rates increased at 96 h. Conclusion Overall, this study determined that sublethal concentrations of ClO2 produced alterations on antioxidant systems, neurotoxicity refected on swimming performances, and variations in cardiac rhythm on treated tadpoles. Thus, our fndings highlighted the need for urgent monitoring of this chemical in the aquatic ecosystems.Fil: Peltzer, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Cuzziol Boccioni, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Attademo, Andres Maximiliano. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martinuzzi, Candela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Colussi, Carlina Leila. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Lajmanovich, Rafael Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

First evaluation of novel potential synergistic effects of glyphosate and arsenic mixture on Rhinella arenarum (Anura: Bufonidae) tadpoles

The toxicity of glyphosate-based herbicide (GBH) and arsenite (As(III)) as individual toxicants and in mixture(50:50 v/v, GBH-As(III)) was determined in Rhinella arenarum tadpoles during acute (48 h) and chronic assays (22days). In both types of assays, the levels of enzymatic activity [Acetylcholinesterase (AChE), Carboxylesterase(CbE), and Glutathione S-transferase (GST)] and the levels of thyroid hormones (triiodothyronine; T3 andthyroxine; T4) were examined. Additionally, the mitotic index (MI) of red blood cells (RBCs) and DNA damageindex were calculated for the chronic assay. The results showed that the LC50 values at 48 h were 45.95 mg/L forGBH, 37.32 mg/L for As(III), and 30.31 mg/L for GBH-As(III) (with similar NOEC ¼ 10 mg/L and LOEC ¼ 20 mg/L between the three treatments). In the acute assay, Marking´s additive index (S ¼ 2.72) indicated synergistictoxicity for GBH-As(III). In larvae treated with GBH and As(III) at the NOEC-48h (10 mg/L), AChE activityincreased by 36.25% and 33.05% respectively, CbE activity increased by 22.25% and 39.05 % respectively, andGST activity increased by 46.75% with the individual treatment with GBH and by 131.65 % with the GBH-As(III)mixture. Larvae exposed to the GBH-As(III) mixture also showed increased levels of T4 (25.67 %). In the chronicassay at NOEC-48h/8 (1.25 mg/L), As(III) and GBH-As(III) inhibited AChE activity (by 39.46 % and 35.65%,respectively), but did not alter CbE activity. In addition, As(III) highly increased (93.7 %) GST activity. GBHAs(III)increased T3 (97.34%) and T4 (540.93%) levels. Finally, GBH-As(III) increased the MI of RBCs andDNA damage. This study demonstrated strong synergistic toxicity of the GBH-As(III) mixture, negatively alteringantioxidant systems and thyroid hormone levels, with consequences on RBC proliferation and DNA damage intreated R. arenarum tadpoles.Fil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Peltzer, Paola. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Attademo, Andres Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; ArgentinaFil: Martinuzzi, Candela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; ArgentinaFil: Simoniello, María F.. Universidad Nacional del Litoral; ArgentinaFil: Colussi, Carlina Leila. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; ArgentinaFil: Cuzziol Boccioni, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; ArgentinaFil: Sigrist, Mirna. Universidad Nacional del Litoral; Argentin

Toxicity assessment at different experimental scenarios with glyphosate, chlorpyrifos and antibiotics in Rhinella arenarum (Anura: Bufonidae) tadpoles

The presence of pesticides as well as that of several antibiotics provided at a great scale to poultry, cattle, and swine in aquatic environments within agroecosystems is a matter of growing concern. The objective of the present study was to characterize the sublethal effects of four environmental toxic compounds at two experimental pollution scenarios on the morphology, development and thyroid (T4), acetylcholinesterase (AChE) and glutathione S-transferase (GST) levels in Rhinella arenarum tadpoles. The first experimental pollution scenario aimed to evaluate the individual and mixed toxicity (50:50% v/v) of a glyphosate-based herbicide (GBH) and the antibiotic ciprofloxacin (CIP) on earlier developmental stages. The second experimental pollution scenario aimed to evaluate the effects of other toxic compounds (the insecticide chlorpyrifos (CP) and the antibiotic amoxicillin (AMX)) added to the ones from the first scenario on previously exposed premetamorphic tadpoles. In all the treatments of the first pollution scenario, the most conspicuous effect observed in early-stage tadpoles was a high prevalence of morphological abnormalities. Exposure to GBH and to its mixture with CIP also led to a significant decrease in T4 levels and lower development. Both pollutant combinations from the second experimental scenario significantly increased T4 levels, inhibited AChE activities, and led to lower development, whereas the quaternary mixture led to a significant decrease in GST levels. The alterations here revealed by our approaches in several morphological and biochemical endpoints allow characterizing the ecotoxicological risk for anurans exposed to complex mixtures of pollutants that frequently occur in aquatic systems.Fil: Cuzziol Boccioni, Ana Paula. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Lajmanovich, Rafael Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; ArgentinaFil: Peltzer, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; ArgentinaFil: Attademo, Andres Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; ArgentinaFil: Martinuzzi, Candela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Saneamiento Ambiental. Cátedra de Ecotoxicología; Argentin

Morphological and histological abnormalities of the neotropical toad, Rhinella arenarum (Anura: Bufonidae) larvae exposed to dexamethasone

Dexamethasone (DEX) is a glucocorticoid highly effective as an anti-inflammatory, immunosuppressant and decongestant drug. In the present study, a preliminary acute toxicity test was assayed in order to determinate DEX median-lethal, lowest-observed-effect and the no-observed-effect concentrations (LC50, LOEC and NOEC, respectively) on the common toad embryos (Rhinella arenarum). Also, morphological and histological abnormalities from five body larval regions, liver melanomacrophages (MM) and glutathione S-transferase (GST) activity were evaluated in the toad larvae to characterize the chronic sublethal effects of DEX (1–1,000 µg L−L). Results of the acute test showed that the LC50 of DEX at 96 h of exposure for the toad embryos (GS 18–20) was 10.720 mg L−g, and the LOEC was 1 µg L−g. In the chronic assay, the larval development and body length were significantly affected. DEX exposition also induced teratogenic effects. Most frequent external abnormalities observed in DEX-treated larvae included abdominal edema and swollen body, abnormal gut coiling and visceral congestion. Intestinal dysplasia was recurrent in cross-section of all DEX-treated larvae. Neural, conjunctive and renal epithelial cells were also affected. Significant increase in liver MM number and size, and GST activity levels were also registered in DEX treatments with respect to controls. The evaluation of a variety of biomarkers provided clear evidence of toad larvae sensitivity to DEX, and the ecotoxicological risk of these pharmaceuticals, commonly found in different water bodies worldwide on aquatic animals.Fil: Cuzziol Boccioni, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Peltzer, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Martinuzzi, Candela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Attademo, Andres Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Leon, Evelina Jesica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Lajmanovich, Rafael Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

Histological and immunohistochemical characterization of the integument and parotoids glands Rhinella bergi (Anura: Bufsonidae): Development and differentiation

A detailed description of the tegument and parotoid glands of pre-metamorphic, post-metamorphic, juvenile and adult individuals of Rhinella bergi is presented to provide an exhaustive analysis of the integumentary characteristics of this species. Fragments of the tegument were fixed in Bouin solution and preserved in buffered Formol 10%. Subsequently, scanning electron microscopy (SEM) was performed to characterize the macroscopic structure of these regions. Microscopic observations were made from histological sections stained with Hematoxylin and Eosin, Alcian Blue (pH 2,5), PAS-H, Coomassie Blue, Oil Red, and Bielschowsky Impregnation. There were three types of protuberance: warts, tubers, and thorns. These structures became evident from post-metamorphic stages. The ventral surface shows elevations similar to flat warts; however, tubers and spines are absent. Histologically, each structure consists of a spongy dermis of lax connective tissue and dense and compact dermis, associated with granular glands and a keratinized epidermis. The latter, in the dorsal region, forms projections called thorns. The granular glands accumulate, and their alveoli increase in size progressively. This work provides a morphological and histological description of the integument and the parotoid glands during the larval and post-metamorphic stage of the genus Rhinella, with aspects described for the first time in the genus.Fil: Olea, Gabriela Beatriz. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnología en Reproducción Animal; ArgentinaFil: Cheij, Esteban Omar. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Curi, Lucila Marilén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Cuzziol Boccioni, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Cespedez, Jorge Abel. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Lombardo, Daniel Marcelo. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnología en Reproducción Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Effects of the emulsifiable herbicide Dicamba on amphibian tadpoles: an underestimated toxicity risk?

The effects of exposure to the herbicide Dicamba (DIC) on tadpoles of two amphibian species, Scinax nasicus and Elachistocleis bicolor, were assessed. Mortality and biochemical sublethal effects were evaluated using acetylcholinesterase (AChE), glutathione S-transferase (GST), glutathione reductase (GR), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) activities and thyroid hormone (T4) levels. The LC50 value at 48h was 0.859 mg L−1 for S. nasicus and 0.221 mg L−1 for E. bicolor tadpoles. After exposure to sublethal DIC concentrations for 48 h, GST activity increased in S. nasicus but significantly decreased in E. bicolor with respect to controls. GR activity decreased only in S. nasicus at all the tested DIC concentrations. AChE activity was significantly inhibited in both S. nasicus and E. bicolor tadpoles at 48 h. DIC also caused significant changes in transamination, as evidenced by an increase in AST and ALT activities in both amphibian species. T4 levels were higher in DIC-treated tadpoles of both species than in controls. The DIC-induced biochemical alterations in glutathione system enzymes and transaminases indicate lesions in liver tissues and cellular function. Moreover, the observed AChE inhibition could lead to the accumulation of acetylcholine, excessively stimulating postsynaptic receptors, and the increase in T4 levels in both species may indicate an overactive thyroid. The commercial DIC formulation showed a high biotoxicity in the two amphibian native species after short-term exposure, controversially differing from the toxicity level indicated in the official fact sheet data. This fact highlights the need for an urgent re-categorization and reevaluation of DIC toxicity in native species.Fil: Attademo, Andres Maximiliano. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Peltzer, Paola. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Cuzziol Boccioni, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Martinuzzi, Candela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Simonielo, Fernanda. Universidad Nacional del Litoral; ArgentinaFil: Repetti, María Rosa. Universidad Nacional del Litoral; Argentin

Environmental quality and ecotoxicity of sediments from the lower Salado River basin (Santa Fe, Argentina) on amphibian larvae

The lower Salado River basin receive agricultural, industrial and domestic waste water. So, the aim was to evaluate the quality of three sampling sites that belong to the Salado River basin (S1: Cululú stream; S2: Salado River, at Esperanza City, S3: Salado River at Santo Tomé City) based on physicochemical parameters, metals and pesticides analyses and ecotoxicity on Rhinella arenarum larvae. R. arenarum larvae (Gosner Stage -GS- 25) were chronically exposed (504h) to complex matrixes of surface water and sediment samples of each site for the determination of the survival rate. Biomarkers of oxidative stress, neurotoxicity and genotoxicity were analyzed in R. arenarum larvae (GS. 25) after exposure (96h) to the complex matrix of water and sediment. The water quality index showed a marginal quality for all sites, influenced mainly by low dissolved oxygen, high total suspended solid, phosphate, nitrite, conductivity, Pb, Cr and Cu levels. Metal concentrations were higher in sediment than in water samples (˜34-35000 times). In total, thirty different pesticides were detected in all water and sediment samples, S1 presented the greatest variety (26). Glyphosate and AMPA were detected in sediments from all sites, being higher in S3. N,N-Diethyl-meta-toluamide (DEET) and atrazine were detected in all water samples. Greatest mortality was observed in larvae exposed to samples from S1 from 288h (43.3%), reaching a maximum value of 50% at 408h. Oxidative stress and genotoxicity were observed in larvae exposed to S1 and S3 matrix samples. Neurotoxicity was observed in larvae exposed to all matrix samples. The integrated biomarker response index showed that larvae exposed to S1 and S3 were the most affected. According to the physicochemical data and the ecotoxicity assessment, this important river basin is significantly degraded and may represent a risk to aquatic biota, especially for R. arenarum larvae.Fil: Peluso, Julieta. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Aronzon, Carolina Mariel. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Martínez Chehda, Agostina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Cuzziol Boccioni, Ana Paula. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Peltzer, Paola. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de Gerónimo, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: Aparicio, Virginia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: González, Florencia. Comisión Nacional de Energía Atómica; ArgentinaFil: Valenzuela, Lautaro Emanuel. Comisión Nacional de Energía Atómica; ArgentinaFil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin