Marcelo Larramendy - Academia.edu (original) (raw)

Papers by Marcelo Larramendy

Issues in toxicology, 2017

Ecotoxicology and Genotoxicology: Non-traditional Aquatic Models intends to stimulate practical d... more Ecotoxicology and Genotoxicology: Non-traditional Aquatic Models intends to stimulate practical discussions on the use of non-conventional biotic matrices to address scientific challenges faced in these fields. It provides real-life examples to convey that the use of a non-conventional animal model, far from being a scientific conundrum, may instead provide real answers to some of our planet's problems. In this epilogue, we summarise the book and we hope that the importance of the status of the environment using autochthonous, non-target species, which are truly exposed to locally used xenobiotic agents, is realised.

Apple Academic Press eBooks, Jun 11, 2015

Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1983

In a coordinated research programme sponsored by the International Atomic Energy Agency, the freq... more In a coordinated research programme sponsored by the International Atomic Energy Agency, the frequencies of chromosomal aberrations induced in peripheral blood lymphocytes (in vitro) by 250 kV X-rays at low doses (0.4, l, 2, 3, 5, 10 and 30 rad) were determined. Blood from 2 donors was used to conduct one master experiment at these dose levels. The culture time used was 48 h and all samples including the controls were processed according to a standard protocol. The coded slides were scored by investigators from 10 participating laboratories. The main results are the following: (1) the frequencies of all types of chromosome aberrations at 0.4 rad are significantly lower than the control values; (2) there is no increase in the frequencies of dicentrics up to 2 rad and in those of terminal deletions up to

Mutation Research/Genetic Toxicology, 1980

Ecotoxicology

Imazethapyr, a post-emergent herbicide used in worldwide soybean and corn crops, induces genetic ... more Imazethapyr, a post-emergent herbicide used in worldwide soybean and corn crops, induces genetic and biochemical alterations in aquatic vertebrates. This study examined relationship between biomarkers at different organization levels and imazethapyr real-life route exposure in Boana pulchella adults. Frogs were exposed to imazethapyr-based formulation Pivot® H (10.59%) at concentrations representing possible acute routes: eld runoff (S1:10 mg.L − 1), direct foliar application with posterior frog presence (S2:100 mg.L − 1) and with frog presence (S3:1000 mg.L − 1). Post-exposure, endpoints levels were evaluated: organism alterations, biochemical activities and cytogenetic assays. Forty-eight hours postexposure, antioxidant enzymes decrease, micronuclei induction and DNA damage were observed in all scenarios; while cholinesterase activity increase and body condition reduction were observed in frogexposed to S3. Ninety-six hours post-exposure, frogs showed glutathione-S-transferase inhibition in S1, micronuclei induction in S2 and S3, and DNA-damage increase in S3. Herbicides routes of exposures in real-life could indicate that authorized applications have a risk to frogs populations.

Encuentro de Becarios de la UNLP (EBEC) (La Plata, 2018), Apr 1, 2019

Small fish are increasingly used as organism toxicity models, and one of these, the ten spotted l... more Small fish are increasingly used as organism toxicity models, and one of these, the ten spotted live-bearer fish (Cnesterodon decemmaculatus), has recently been employed in geno- and cyto-toxicity testing. Genotoxic biomarkers are largely employed for monitoring anthropogenic activities, including industrial, agricultural, and urban waste, with clear adverse effects on human health and wildlife populations. The increased attention to the use of non-traditional species of fish in ecotoxicology and genotoxicology research lies in their ability not only to reveal the genotoxic and cytotoxic effects of many potential environmental xenobiotics, but also to help researchers understand the behaviour of real ecosystems. This chapter presents an overview of selected research that has led to the use of C. decemmaculatus as a reliable and valid model of ecotoxicology and genotoxicology in in vivo and in situ studies.

Amphibians as animal models have long been employed as indicators of environmental quality and to... more Amphibians as animal models have long been employed as indicators of environmental quality and to detect toxicity risks of environmental pollutants. The increased attention to the use of non-traditional species of amphibians in ecotoxicology and genotoxicology research lies in their ability not only to reveal the toxic and genotoxic effects of many potential environmental xenobiotics, but also to help researchers understand the behaviour of real ecosystems. This chapter presents an overview of selected research that has led to the use of the common tree frog Hypsiboas pulchellus as a reliable and valid model in in vivo and in situ studies of aquatic pollution.

One of the major goals of our research laboratory is to evaluate comparatively the genotoxic and ... more One of the major goals of our research laboratory is to evaluate comparatively the genotoxic and cytotoxic effects exerted by several pure agrochemicals and their technical formulations commonly used in Argentina on vertebrate cells in vitro and in vivo. Among them are listed the herbicides 2,4-D and 2,4-D DMA®, dicamba and Banvel®, the fungicide zineb and Az-zurro®, the insecticides carbofuran and Furadan®, pirimicarb and Aficida®, and the endectocide ivermectin and Ivomec®. The SCE, comet assay, micronuclei, chromosomal aberrations, cell-cycle progression, spindle disturbances, MTT and neutral red assays were used as end-points for geno and cytotoxicity. Overall, the results clearly demonstrated that the damage induced by the commercial formulations is in general greater than that produced by the pure pesticides, suggesting the presence of deleterious components in the excipients with a toxic additive effect over the pure agrochemicals. Accordingly, the results highlight that: 1) A complete knowledge of the toxic effect/s of the active ingredient is not enough in biomonitoring studies; 2) Pesticide/s toxic effect/s should be evaluated according to the commercial formulation available in market; 3) The deleterious effect/s of the excipient/s present within the commercial formulation should not be either discarded nor underestimated, and 4) A single bioassay is not enough to characterize the toxicity of a agrochemical under study.

Archives of Environmental Contamination and Toxicology, 2021

Imazetapir is a herbicide used in soybean and corn crops worldwide. Ecotoxicological studies have... more Imazetapir is a herbicide used in soybean and corn crops worldwide. Ecotoxicological studies have shown that imazetapir promotes genotoxic, biochemical and individual effects in aquatic vertebrates. In this study, we evaluated the response of different biomarkers in adult specimens of Leptodactylus latinasus exposed under laboratory conditions to the imazetapir based-formulation Pivot® H (10.59% Imazetapir) mimicking two possible real acute scenarios. Both exposure scenarios considered were the runoff simulation (scenario1: 10 mg/L) and the direct spraying application (scenario2: 1000 mg/L). Different endpoints were evaluated at several ecotoxicological levels after 48 and 96 h of exposure including individual (biometric indices and behavior alterations), histological (liver pigmentation and tissue alterations), biochemical (catalase, glutathione system and cholinesterase activities) and genotoxic effects (induction of micronuclei and nuclear abnormalities). The exposure to Pivot® H during 48 h, induced inhibition of the glutathione-S-transferase activity in scenario1 and an increase of hepatic tissue alterations and acetyl-cholinesterase levels in scenario2. After 96 h, we demonstrated that imazetapir formulation induced a decrease in melanin and hemosiderin, an increase in catalase activity and induction of micronuclei in scenario1 while in scenario2 there was a decrease in the hepatosomatic index, and an increase in liver alterations and melanin reduction. The multivariate analysis allows to correlate biomarkers at the same level in exposed specimens. Accordingly, we conclude that populations of L. latinasus could be at risk after real scenarios of exposure to pesticides corroborating that the species is a good model for ecotoxicological studies in the region.

Toxicology in Vitro, 2020

A combined approach employing alkaline single cell gel electrophoresis (SCGE) and cytokinesis-blo... more A combined approach employing alkaline single cell gel electrophoresis (SCGE) and cytokinesis-blocked micronucleus (MNs) cytome bioassays was adopted to assess the deleterious properties of the auxinic 2,4-dichlorophenoxyacetic acid (2,4-D) and its microparticulated low volatility product Dedalo Elite (30% a.i.) on Chinese hamster ovary (CHO-K1) cells. Cytotoxicity was estimated by neutral red uptake (NRU), succinic dehydrogenase activity (MTT) and apoptosis assessment. Both compounds were assayed at 0.1-10 μg/ml concentration range. Whereas exposed CHO-K1 cells revealed a statistically significant enhancement of MNs when 10 μg 2,4-D/ml was assayed, MNs were only achieved in cells treated with 2 μg Dedalo Elite/ml. A diminution in the nuclear division index was only achieved after exposure to Dedalo Elite within the 1-10 μg/ml concentration range. Whereas increased genetic damage index was achieved when 6 and 10 μg 2,4-D/ml were assayed, GDI induction was observed in treatments employing 4 μg Dedalo Elite/ml. Both compounds induced cytotoxicity by inhibition of both lysosomal and MTT activities by enhancing the frequencies of early and late apoptotic cells. Our results not only indicate the genotoxic and cytotoxic potential of 2,4-D and its microparticulated marketplace formulation, but also highlight the risk these agrochemicals present towards the biota and human health.

Environmental Science and Pollution Research, 2019

Genotoxic, biochemical, and individual organizational effects on Leptodactylus latinasus tadpoles... more Genotoxic, biochemical, and individual organizational effects on Leptodactylus latinasus tadpoles were evaluated after exposure to an imazethapyr (IMZT)-based commercial herbicide formulation, Pivot® H (10.59% IMZT). A determination of the value of the lethal concentration (LC50) was determined as a toxicological endpoint. Alterations in animal behavior and morphological abnormalities as well as cholinesterase (ChE), catalase (CAT), and glutathione S-transferase (GST) activities were employed as individual sublethal endpoints. Micronuclei frequencies (MNs), binucleated cells (BNs), blebbed nuclei (BLs), lobed nuclei (LBs), notched nuclei (NTs), erythroplastids (EPs), and evaluation of DNA strand breaks were employed as genotoxic endpoints. All biomarkers were evaluated after 48 and 96 h of exposure to concentrations of IMZT within 0.07-4.89 mg/L. LC50 96h values of 1.01 and 0.29 mg/L IMZT were obtained for Gosner stages 25 and 36, respectively. Irregular swimming, diamond body shape, and decreased frequency of keratodonts were detected at both sampling times. Results showed that IMZT increased GST activity and MN frequency at 48 and 96 h of exposure. Other nuclear abnormalities were also observed in the circulating erythrocytes of tadpoles, i.e., NT and BL values after 48 h, and LN, BL, and EP values after 96 h. Finally, results showed that IMZT within 0.07-0.22 mg/L increased the genetic damage index in tadpoles exposed for both exposure times (48 and 96 h). This study is the first to report the sublethal biochemical effects of IMZT in anurans and is also the first report using L. latinasus tadpoles as a bioindicator for ecotoxicological studies.

Chemosphere, 2020

Glyphosate (GLY)-dicamba (DIC) and GLY-flurochloridone (FLC) are herbicide mixtures which are wid... more Glyphosate (GLY)-dicamba (DIC) and GLY-flurochloridone (FLC) are herbicide mixtures which are widely used for treating fallow containing glyphosate resistant weeds. The aim of this study was to evaluate the acute toxic effects and the prevailing interactions on stage 36 tadpoles of the anuran species Rhinella arenarum when exposed to equitoxic and non-equitoxic combinations of these herbicide combinations. Experiments were realized using the following combinations of commercial formulations: 48% GLY-based Credit® + 57.71% DIC-based Banvel® and 48% GLY-based Credit® + 25% FLC-based Twin Pack Gold®. GLY-DIC and GLY-FLC equitoxic mixtures were assayed mixing each constituent with an equivalent individual toxicity able to induce the same lethality effect. After 96 h of exposure, GLY-DIC and GLY-FLC equitoxic mixtures presented toxic unit 50 values (TU50 96h) of 1.74 (confidence interval: 1.58-1.92) and 1.54 (confidence interval: 1.46-1.62) respectively, indicating the presence of a weak antagonistic interaction as TU values were greater than 1. For their part, most non-equitoxic combinations of GLY-DIC and GLY-FLC tested did not significantly differ from additivity, the only exception being when DIC and FLC were fixed at 0.33 TUs, where a weak antagonism was observed. Overall, results indicate that the toxicity of both GLY-DIC and GLY-FLC mixtures to R. arenarum tadpoles vary from additive to slightly antagonistic, depending on the proportion of constituting herbicide formulations present in the mixture.

Environmental Pollution, 2018

We analyzed the acute toxicity of the 48% glyphosate (GLY)-based Credit ® , the 57.71% dicamba (D... more We analyzed the acute toxicity of the 48% glyphosate (GLY)-based Credit ® , the 57.71% dicamba (DIC)based Kamba ® , and the 83.5% 2,4-dichlorophenoxyacetic acid (2,4-D)-based Weedar ® Full, alone and as mixtures on the fish Cnesterodon decemmaculatus. Mortality revealed the LC 50 96h values of 91.73 mg L À1 (range: 86.80e98.00 mg L À1), 1401.57 mg L À1 (range: 1243.78e1527.35) and 678.04 mg L À1 (range: 639.35e718.04 mg L À1) for GLY, DIC and 2,4-D, respectively. Mean values for the toxic unit (TU) that induced 50% mortality (TU 50 96h) of fish exposed to equitoxic mixtures were 1.67 (range: 1.65e1.69) for Credit ® and Kamba ® and 1.28 (range: 1.20e1.36) for Credit ® and Weedar ® Full suggesting that both mixtures are antagonic. Non-equitoxic combinations demonstrated an antagonistic interaction of herbicides Credit ® and Kamba ® , whereas a synergistic effect was observed for Credit ® and Weedar ® Full formulations. GLY and DIC as a mixture demonstrated lower toxicity on non-target species compared to GLY and 2,4-D in combination, at least for C. decemmaculatus, leading to the conclusion that the former combination could be strongly recommended in further agricultural practices.

Environmental Pollution, 2018

Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are two of the most applied auxinic herb... more Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are two of the most applied auxinic herbicides worldwide, both individually and as part of a mixture. However, the toxicity and interactions achieved when applied as a mixture have not yet been characterised. The equitoxic and non-equitoxic acute toxicity exerted by binary mixtures of Banvel ® (57.71% DIC) and DMA ® (58.4% 2,4-D) on the Neotropical fish Cnesterodon decemmaculatus were evaluated. Results revealed mean values of 1.02 (range, 0.96e1.08) for the toxic unit (TU) that induced 50% mortality (TU 50 96 h) to the fish exposed to binary equitoxic mixtures of the commercial formulations Banvel ® eDMA ®. These results suggest that the mixture is nearly concentration additive. Furthermore, results demonstrated the occurrence of synergistic interaction when non-equitoxic combinations of Banvel ®-or DMA ®-formulated herbicides were assayed. In this context and regardless of their concentrations, either Banvel ®-or DMA ®-induced toxicity were synergised by the presence of the counterpart within mixtures. The present study represents the first evidence of the lethality exerted by mixtures of two auxinic herbicidesdnamely, DIC and 2,4-Ddreported to date for fish and other biotic matrices. When C. decemmaculatus is used as the target organism, a synergistic pattern is observed following exposure to a mixture of both herbicides.

Environmental Pollution, 2018

Issues in toxicology, 2017

Ecotoxicology and Genotoxicology: Non-traditional Aquatic Models intends to stimulate practical d... more Ecotoxicology and Genotoxicology: Non-traditional Aquatic Models intends to stimulate practical discussions on the use of non-conventional biotic matrices to address scientific challenges faced in these fields. It provides real-life examples to convey that the use of a non-conventional animal model, far from being a scientific conundrum, may instead provide real answers to some of our planet's problems. In this epilogue, we summarise the book and we hope that the importance of the status of the environment using autochthonous, non-target species, which are truly exposed to locally used xenobiotic agents, is realised.

Apple Academic Press eBooks, Jun 11, 2015

Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1983

In a coordinated research programme sponsored by the International Atomic Energy Agency, the freq... more In a coordinated research programme sponsored by the International Atomic Energy Agency, the frequencies of chromosomal aberrations induced in peripheral blood lymphocytes (in vitro) by 250 kV X-rays at low doses (0.4, l, 2, 3, 5, 10 and 30 rad) were determined. Blood from 2 donors was used to conduct one master experiment at these dose levels. The culture time used was 48 h and all samples including the controls were processed according to a standard protocol. The coded slides were scored by investigators from 10 participating laboratories. The main results are the following: (1) the frequencies of all types of chromosome aberrations at 0.4 rad are significantly lower than the control values; (2) there is no increase in the frequencies of dicentrics up to 2 rad and in those of terminal deletions up to

Mutation Research/Genetic Toxicology, 1980

Ecotoxicology

Imazethapyr, a post-emergent herbicide used in worldwide soybean and corn crops, induces genetic ... more Imazethapyr, a post-emergent herbicide used in worldwide soybean and corn crops, induces genetic and biochemical alterations in aquatic vertebrates. This study examined relationship between biomarkers at different organization levels and imazethapyr real-life route exposure in Boana pulchella adults. Frogs were exposed to imazethapyr-based formulation Pivot® H (10.59%) at concentrations representing possible acute routes: eld runoff (S1:10 mg.L − 1), direct foliar application with posterior frog presence (S2:100 mg.L − 1) and with frog presence (S3:1000 mg.L − 1). Post-exposure, endpoints levels were evaluated: organism alterations, biochemical activities and cytogenetic assays. Forty-eight hours postexposure, antioxidant enzymes decrease, micronuclei induction and DNA damage were observed in all scenarios; while cholinesterase activity increase and body condition reduction were observed in frogexposed to S3. Ninety-six hours post-exposure, frogs showed glutathione-S-transferase inhibition in S1, micronuclei induction in S2 and S3, and DNA-damage increase in S3. Herbicides routes of exposures in real-life could indicate that authorized applications have a risk to frogs populations.

Encuentro de Becarios de la UNLP (EBEC) (La Plata, 2018), Apr 1, 2019

Small fish are increasingly used as organism toxicity models, and one of these, the ten spotted l... more Small fish are increasingly used as organism toxicity models, and one of these, the ten spotted live-bearer fish (Cnesterodon decemmaculatus), has recently been employed in geno- and cyto-toxicity testing. Genotoxic biomarkers are largely employed for monitoring anthropogenic activities, including industrial, agricultural, and urban waste, with clear adverse effects on human health and wildlife populations. The increased attention to the use of non-traditional species of fish in ecotoxicology and genotoxicology research lies in their ability not only to reveal the genotoxic and cytotoxic effects of many potential environmental xenobiotics, but also to help researchers understand the behaviour of real ecosystems. This chapter presents an overview of selected research that has led to the use of C. decemmaculatus as a reliable and valid model of ecotoxicology and genotoxicology in in vivo and in situ studies.

Amphibians as animal models have long been employed as indicators of environmental quality and to... more Amphibians as animal models have long been employed as indicators of environmental quality and to detect toxicity risks of environmental pollutants. The increased attention to the use of non-traditional species of amphibians in ecotoxicology and genotoxicology research lies in their ability not only to reveal the toxic and genotoxic effects of many potential environmental xenobiotics, but also to help researchers understand the behaviour of real ecosystems. This chapter presents an overview of selected research that has led to the use of the common tree frog Hypsiboas pulchellus as a reliable and valid model in in vivo and in situ studies of aquatic pollution.

One of the major goals of our research laboratory is to evaluate comparatively the genotoxic and ... more One of the major goals of our research laboratory is to evaluate comparatively the genotoxic and cytotoxic effects exerted by several pure agrochemicals and their technical formulations commonly used in Argentina on vertebrate cells in vitro and in vivo. Among them are listed the herbicides 2,4-D and 2,4-D DMA®, dicamba and Banvel®, the fungicide zineb and Az-zurro®, the insecticides carbofuran and Furadan®, pirimicarb and Aficida®, and the endectocide ivermectin and Ivomec®. The SCE, comet assay, micronuclei, chromosomal aberrations, cell-cycle progression, spindle disturbances, MTT and neutral red assays were used as end-points for geno and cytotoxicity. Overall, the results clearly demonstrated that the damage induced by the commercial formulations is in general greater than that produced by the pure pesticides, suggesting the presence of deleterious components in the excipients with a toxic additive effect over the pure agrochemicals. Accordingly, the results highlight that: 1) A complete knowledge of the toxic effect/s of the active ingredient is not enough in biomonitoring studies; 2) Pesticide/s toxic effect/s should be evaluated according to the commercial formulation available in market; 3) The deleterious effect/s of the excipient/s present within the commercial formulation should not be either discarded nor underestimated, and 4) A single bioassay is not enough to characterize the toxicity of a agrochemical under study.

Archives of Environmental Contamination and Toxicology, 2021

Imazetapir is a herbicide used in soybean and corn crops worldwide. Ecotoxicological studies have... more Imazetapir is a herbicide used in soybean and corn crops worldwide. Ecotoxicological studies have shown that imazetapir promotes genotoxic, biochemical and individual effects in aquatic vertebrates. In this study, we evaluated the response of different biomarkers in adult specimens of Leptodactylus latinasus exposed under laboratory conditions to the imazetapir based-formulation Pivot® H (10.59% Imazetapir) mimicking two possible real acute scenarios. Both exposure scenarios considered were the runoff simulation (scenario1: 10 mg/L) and the direct spraying application (scenario2: 1000 mg/L). Different endpoints were evaluated at several ecotoxicological levels after 48 and 96 h of exposure including individual (biometric indices and behavior alterations), histological (liver pigmentation and tissue alterations), biochemical (catalase, glutathione system and cholinesterase activities) and genotoxic effects (induction of micronuclei and nuclear abnormalities). The exposure to Pivot® H during 48 h, induced inhibition of the glutathione-S-transferase activity in scenario1 and an increase of hepatic tissue alterations and acetyl-cholinesterase levels in scenario2. After 96 h, we demonstrated that imazetapir formulation induced a decrease in melanin and hemosiderin, an increase in catalase activity and induction of micronuclei in scenario1 while in scenario2 there was a decrease in the hepatosomatic index, and an increase in liver alterations and melanin reduction. The multivariate analysis allows to correlate biomarkers at the same level in exposed specimens. Accordingly, we conclude that populations of L. latinasus could be at risk after real scenarios of exposure to pesticides corroborating that the species is a good model for ecotoxicological studies in the region.

Toxicology in Vitro, 2020

A combined approach employing alkaline single cell gel electrophoresis (SCGE) and cytokinesis-blo... more A combined approach employing alkaline single cell gel electrophoresis (SCGE) and cytokinesis-blocked micronucleus (MNs) cytome bioassays was adopted to assess the deleterious properties of the auxinic 2,4-dichlorophenoxyacetic acid (2,4-D) and its microparticulated low volatility product Dedalo Elite (30% a.i.) on Chinese hamster ovary (CHO-K1) cells. Cytotoxicity was estimated by neutral red uptake (NRU), succinic dehydrogenase activity (MTT) and apoptosis assessment. Both compounds were assayed at 0.1-10 μg/ml concentration range. Whereas exposed CHO-K1 cells revealed a statistically significant enhancement of MNs when 10 μg 2,4-D/ml was assayed, MNs were only achieved in cells treated with 2 μg Dedalo Elite/ml. A diminution in the nuclear division index was only achieved after exposure to Dedalo Elite within the 1-10 μg/ml concentration range. Whereas increased genetic damage index was achieved when 6 and 10 μg 2,4-D/ml were assayed, GDI induction was observed in treatments employing 4 μg Dedalo Elite/ml. Both compounds induced cytotoxicity by inhibition of both lysosomal and MTT activities by enhancing the frequencies of early and late apoptotic cells. Our results not only indicate the genotoxic and cytotoxic potential of 2,4-D and its microparticulated marketplace formulation, but also highlight the risk these agrochemicals present towards the biota and human health.

Environmental Science and Pollution Research, 2019

Genotoxic, biochemical, and individual organizational effects on Leptodactylus latinasus tadpoles... more Genotoxic, biochemical, and individual organizational effects on Leptodactylus latinasus tadpoles were evaluated after exposure to an imazethapyr (IMZT)-based commercial herbicide formulation, Pivot® H (10.59% IMZT). A determination of the value of the lethal concentration (LC50) was determined as a toxicological endpoint. Alterations in animal behavior and morphological abnormalities as well as cholinesterase (ChE), catalase (CAT), and glutathione S-transferase (GST) activities were employed as individual sublethal endpoints. Micronuclei frequencies (MNs), binucleated cells (BNs), blebbed nuclei (BLs), lobed nuclei (LBs), notched nuclei (NTs), erythroplastids (EPs), and evaluation of DNA strand breaks were employed as genotoxic endpoints. All biomarkers were evaluated after 48 and 96 h of exposure to concentrations of IMZT within 0.07-4.89 mg/L. LC50 96h values of 1.01 and 0.29 mg/L IMZT were obtained for Gosner stages 25 and 36, respectively. Irregular swimming, diamond body shape, and decreased frequency of keratodonts were detected at both sampling times. Results showed that IMZT increased GST activity and MN frequency at 48 and 96 h of exposure. Other nuclear abnormalities were also observed in the circulating erythrocytes of tadpoles, i.e., NT and BL values after 48 h, and LN, BL, and EP values after 96 h. Finally, results showed that IMZT within 0.07-0.22 mg/L increased the genetic damage index in tadpoles exposed for both exposure times (48 and 96 h). This study is the first to report the sublethal biochemical effects of IMZT in anurans and is also the first report using L. latinasus tadpoles as a bioindicator for ecotoxicological studies.

Chemosphere, 2020

Glyphosate (GLY)-dicamba (DIC) and GLY-flurochloridone (FLC) are herbicide mixtures which are wid... more Glyphosate (GLY)-dicamba (DIC) and GLY-flurochloridone (FLC) are herbicide mixtures which are widely used for treating fallow containing glyphosate resistant weeds. The aim of this study was to evaluate the acute toxic effects and the prevailing interactions on stage 36 tadpoles of the anuran species Rhinella arenarum when exposed to equitoxic and non-equitoxic combinations of these herbicide combinations. Experiments were realized using the following combinations of commercial formulations: 48% GLY-based Credit® + 57.71% DIC-based Banvel® and 48% GLY-based Credit® + 25% FLC-based Twin Pack Gold®. GLY-DIC and GLY-FLC equitoxic mixtures were assayed mixing each constituent with an equivalent individual toxicity able to induce the same lethality effect. After 96 h of exposure, GLY-DIC and GLY-FLC equitoxic mixtures presented toxic unit 50 values (TU50 96h) of 1.74 (confidence interval: 1.58-1.92) and 1.54 (confidence interval: 1.46-1.62) respectively, indicating the presence of a weak antagonistic interaction as TU values were greater than 1. For their part, most non-equitoxic combinations of GLY-DIC and GLY-FLC tested did not significantly differ from additivity, the only exception being when DIC and FLC were fixed at 0.33 TUs, where a weak antagonism was observed. Overall, results indicate that the toxicity of both GLY-DIC and GLY-FLC mixtures to R. arenarum tadpoles vary from additive to slightly antagonistic, depending on the proportion of constituting herbicide formulations present in the mixture.

Environmental Pollution, 2018

We analyzed the acute toxicity of the 48% glyphosate (GLY)-based Credit ® , the 57.71% dicamba (D... more We analyzed the acute toxicity of the 48% glyphosate (GLY)-based Credit ® , the 57.71% dicamba (DIC)based Kamba ® , and the 83.5% 2,4-dichlorophenoxyacetic acid (2,4-D)-based Weedar ® Full, alone and as mixtures on the fish Cnesterodon decemmaculatus. Mortality revealed the LC 50 96h values of 91.73 mg L À1 (range: 86.80e98.00 mg L À1), 1401.57 mg L À1 (range: 1243.78e1527.35) and 678.04 mg L À1 (range: 639.35e718.04 mg L À1) for GLY, DIC and 2,4-D, respectively. Mean values for the toxic unit (TU) that induced 50% mortality (TU 50 96h) of fish exposed to equitoxic mixtures were 1.67 (range: 1.65e1.69) for Credit ® and Kamba ® and 1.28 (range: 1.20e1.36) for Credit ® and Weedar ® Full suggesting that both mixtures are antagonic. Non-equitoxic combinations demonstrated an antagonistic interaction of herbicides Credit ® and Kamba ® , whereas a synergistic effect was observed for Credit ® and Weedar ® Full formulations. GLY and DIC as a mixture demonstrated lower toxicity on non-target species compared to GLY and 2,4-D in combination, at least for C. decemmaculatus, leading to the conclusion that the former combination could be strongly recommended in further agricultural practices.

Environmental Pollution, 2018

Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are two of the most applied auxinic herb... more Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are two of the most applied auxinic herbicides worldwide, both individually and as part of a mixture. However, the toxicity and interactions achieved when applied as a mixture have not yet been characterised. The equitoxic and non-equitoxic acute toxicity exerted by binary mixtures of Banvel ® (57.71% DIC) and DMA ® (58.4% 2,4-D) on the Neotropical fish Cnesterodon decemmaculatus were evaluated. Results revealed mean values of 1.02 (range, 0.96e1.08) for the toxic unit (TU) that induced 50% mortality (TU 50 96 h) to the fish exposed to binary equitoxic mixtures of the commercial formulations Banvel ® eDMA ®. These results suggest that the mixture is nearly concentration additive. Furthermore, results demonstrated the occurrence of synergistic interaction when non-equitoxic combinations of Banvel ®-or DMA ®-formulated herbicides were assayed. In this context and regardless of their concentrations, either Banvel ®-or DMA ®-induced toxicity were synergised by the presence of the counterpart within mixtures. The present study represents the first evidence of the lethality exerted by mixtures of two auxinic herbicidesdnamely, DIC and 2,4-Ddreported to date for fish and other biotic matrices. When C. decemmaculatus is used as the target organism, a synergistic pattern is observed following exposure to a mixture of both herbicides.

Environmental Pollution, 2018