Search

Chlorpyrifos (CPF) has been used worldwide, but its possible negative effects on macrophytes have been scarcely studied. The main goal of the present work was to assess the potential phytotoxic effects of CPF on different stages (seed and seedling) of the wetland macrophyte Bidens laevis. During the germination of seeds, stimulation of radicle growth at low concentrations of CPF (10 µg/L) and inhibition of its elongation at 80 µg/L CPF were observed. In seedlings, concentrations ≤ 160 µg/L CPF did not exhibit adverse effects on growth after 7 days of exposure, despite the decrease of photosynthetic pigments and carotenoids observed at 40 µg/L CPF compared to the control. Environmentally relevant concentrations of CPF altered neither oxidative stress biomarkers nor pigment contents in seedlings exposed for 48 h, suggesting CPF would be non-toxic to B. laevis in natural scenarios., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Pesticide contamination and its adverse effects on native freshwater species continue to be a worldwide major concern, mainly in developing countries. Passive biomonitoring of pesticide pollution in shallow lakes may be achieved by the simultaneous use of fish and wetland plants. Thus, the present study aimed to evaluate the occurrence of current-use pesticides in the surface water of a shallow lake of the Austral Pampas region (Buenos Aires Province, Argentina) surrounded by intensive agricultural activities and its relationship with a battery of biomarkers, including oxidative stress and genotoxicity, in two native species, the fish Oligosarcus jenynsii and the macrophyte Bidens laevis. A total of 26 pesticide residues were analyzed, and the main ones detected were glyphosate and its metabolite aminomethylphosphonic acid (AMPA), chlorpyrifos, and imidacloprid. In O. jenynsii, hydrogen peroxide (H 2 O 2 ) content in the liver increased with chlorpyrifos occurrence, while malondialdehyde (MDA) levels in the brain and liver increased with the presence of both chlorpyrifos and glyphosate. In B. laevis, H 2 O 2 and MDA levels in leaves and roots increased with AMPA occurrence. Also, leaf H 2 O 2 contents and root MDA levels increased with chlorpyrifos concentration. In contrast, catalase and peroxidase activities in roots decreased with AMPA and chlorpyrifos occurrence. In both species, mainly H 2 O 2 and MDA levels demonstrated their sensitivity to be used as biomarkers in the biomonitoring of current-use pesticide pollution in shallow lakes. Their use may provide information to plan strategies for environmental conservation by government institutions or decision-makers, and to assess the biota health status., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Uco valley (Mendoza, Argentina) suffers the concomitant effect of climate change, anthropic pressure and water scarcity. Moreover chemical pollution to aquatic ecosystems could be another pressuring factor, but it was not studied enough to the present. In this sense, the aim of this study was to assess the occurrence of pesticides, pharmaceuticals and personal care products (PPCPs) in aquatic ecosystems of the Uco Valley and to perform an ecological risk assessment (ERA). The presence of several insecticides (mainly neonicotinoids), herbicides (atrazine, diuron, metolachlor, terbutryn) and fungicides (strobilurins, triazolic and benzimidazolic compounds) in water samples in two seasons, related to crops like vineyards, garlic or fruit trees was associated to medium and high-risk probabilities for aquatic biota. Moreover, PPCPs of the group of non-steroidal anti-inflammatory drugs, parabens and bisphenol A were detected in all the samples and their calculated risk quotients also indicated a high risk. This is the first record of pesticides and PPCPs with an ERA in this growing agricultural oasis. Despite the importance of these findings in Uco Valley for decision makers in the region, this multilevel approach could bring a wide variety of tools for similar regions in with similar productive and environmental conditions, in order to afford actions to reach Sustainable Development Goals. SYNOPSIS: Aquatic ecosystems in arid mountain regions are threatened worldwide. This study reports relevant data about chemical pollution in Central Andes, which could be a useful tool to enhance SDGs' accomplishment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Dicamba (DIC) is one of the most applied auxin herbicides worldwide. Sublethal effects in the South American native fish Jenynsia lineata exposed to DIC concentrations close to environmental concentrations (0.03-30 µg/L) during 48 h were analysed thorough the evaluation of catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD) activities and malondialdehyde (MDA) and H 2 O 2 levels for detecting potential oxidative stress. In gills MDA increased showing oxidative damage probably because of an inefficient antioxidant defense. This response evidenced the important role of gills as an organ of direct contact with waterborne contaminants. In addition, other changes in the biomarkers of oxidative stress were observed such as the inhibition of SOD activities in brain and the inhibition of GST in liver. These results show that short- term exposures to environmentally relevant concentrations of DIC could induce sublethal effects in native fish., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

A research gap exists in baseline concentrations of organic micropollutants in South American rivers. Identification of areas with different degrees of contamination and risk to the inhabitant biota is needed to improve management of freshwater resources. Here we inform the incidence and ecological risk assessment (ERA) of current used pesticides (CUPs), pharmaceutical and personal care products (PPCPs) and cyanotoxins (CTX) measured in two river basins from central Argentina (South America). Risk Quotients approach was used for ERA differentiating wet and dry seasons. High risk was associated to CUPs in both basins (45 % and 30 % of sites from Suquía and Ctalamochita rivers, respectively), mostly in the basins extremes. Main contributors to risk in water were insecticides and herbicides in Suquía river and insecticides and fungicides in Ctalamochita river. In Suquía river sediments, a very high risk was observed in the lower basin, mainly from AMPA contribution. Additionally, 36 % of the sites showed very high risk of PCPPs in Suquía river water, with the highest risk downstream the wastewater treatment plant of Córdoba city. Main contribution was from a psychiatric drug and analgesics. In sediments medium risk was observed at the same places with antibiotics and psychiatrics as main contributors. Few data of PPCPs are available in the Ctalamochita river. The risk in water was low, with one site (downstream Santa Rosa de Calamuchita town) presenting moderated risk caused by an antibiotic. CTX represented in general medium risk in San Roque reservoir, with San Antonio river mouth and the dam exit showing high risk during the wet season. The main contributor was microcystin-LR. Priority chemicals for monitoring or further management include two CUPs, two PPCPs, and one CTX, demonstrating a significant input of pollutants to water ecosystems from different sources and the need to include organic micropollutants in current and future monitoring., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Estuarine saltmarshes from South America are exposed to several anthropogenic impacts due to diverse human activities that occur in both Atlantic/Pacific coastal environments. Primarily, chemical and petrochemical industries negatively impact saltmarshes generating inputs/deposition of non-essential trace elements (NTEs) and polycyclic aromatic hydrocarbons (PAHs) in sediments. The native cordgrass Spartina densiflora inhabits a wide range of environments, from non-impacted to highly impacted areas. It is important to know its performance towards pollution in different environmental settings in South America. The content of Cd, Hg, Pb, and PAHs was determined in the roots and leaves of S. densiflora, bulk sediments (Bs), and rhizosediments (Rs) of estuaries from Argentina, Brazil, and Chile. Differences in NTEs and PAHs levels were observed between Bs, Rs, and Spartina tissues from different saltmarsh areas. Differences in Rs/Bs (RHICF; rhizosediments concentration factors), roots/Bs (RCF; roots concentration factors) and leaves/roots (TF; translocation factors) factors were also found. In terms of NTEs, S. densiflora showed a high capability to increase levels in their Rs (RHICF>1) and bioconcentrate Cd in roots (RCF > 1), while no general translocation (TF < 1) was observed. Conversely, in cordgrass tissues, Bs and Rs, PAHs contents showed RCF and TF > 1, which was in line with lower levels in Rs related to Bs (RHICF<1) in most sites. These findings showed the S. densiflora capacity to retain, remove and/or translocate priority contaminants depending on intrinsic chemical characteristics and the level of contamination. The present study enables future considerations regarding the biomonitoring and phytoremediation/stabilization capabilities of Spartina in coastal environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Monensin is an ionophore antibiotic used as a feed additive and growth promoter in cattle production worldwide. The occurrence of monensin in aquatic surficial ecosystems is of concern due to its possible detrimental effects on human health and native biota. Argentina is one of the most important cattle beef producers worldwide; however, there is little knowledge on the environmental occurrence of monensin and the associated risks to aquatic biota. In this study, we developed a method for the extraction and quantification of monensin in surface water; then, we evaluated the occurrence of monensin in a stream impacted by different animal husbandry's operations, and then, we analyzed the ecological implications of monensin residues on aquatic organisms using the risk quotient (RQ) method. Sampling was carried out on August 2017 from the headwaters to the floodplain of the El Pantanoso stream, Buenos Aires province, Argentina. Monensin detection frequency was 75% (n = 20). The median level was 0.40 μg/L and the maximum concentration was 4.70 μg/L. The main input of monensin was from a cattle slaughterhouse, an activity that has not been considered before in the literature as a source of emission of veterinary pharmaceuticals into the environment. The RQ assessment showed that monensin levels could have potential negative effects on aquatic biota in the sampling site closest to the cattle slaughterhouse. The data obtained in this study shows that monensin was present in El Pantanoso surface waters at levels of high ecotoxicological risk to aquatic biota.

Azoxystrobin (AZX) is a broad-spectrum systemic fungicide massively used worldwide. Its mode of action consists in the inhibition of mitochondrial respiration decreasing the synthesis of ATP and leading to oxidative stress in the target fungus. However, whether this effect occurs in non target organisms has been scarcely studied. The objectives of this work were (1) to evaluate biomarkers of oxidative stress, hematological, physiological and of genotoxicity in the native cichlid fish Australoheros facetus exposed to environmentally relevant concentrations of AZX and (2) to compare these biomarkers in different developmental stages using juvenile and adult fish (n = 6) exposed during 48 h. The exposure concentrations were 0 (negative control, C (-)), 0.05, 0.5, 5 and 50 μg/L AZX of the commercial formulation AMISTAR®. Blood was drawn to evaluate hematology, and DNA damage through the comet assay (CA) and micronucleus test (MN). Genotoxicity was observed by mean of both biomarkers in juvenile and adult fish at 50 μg/L AZX. Samples of liver and gills were used to determine antioxidant enzymes activity, hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) contents. In juvenile fish inhibition of superoxide dismutase (SOD) was observed in liver at 0.05, 5 and 50 μg/L AZX and in gills at 5 and 50 μg/L AZX. Glutathione- S- transferases (GST) activity increased in gills at all AZX concentrations tested. In adult fish, increase of hepatic catalase (CAT) activity at 0.5 and 50 μg/L AZX and MDA content at 50 μg/L AZX were observed. In gills only H 2 O 2 content showed changes at 50 μg/L AZX. The sensitivity showed by gills constitutes the first report about AZX toxicity in this organ. All these negative effects were observed in the range of realistic AZX concentrations, which warns of the possible consequences that it may have on the health of aquatic biota. Differences between juvenile and adult fish demonstrate the relevance of considering the developmental stage on the evaluation of biomarkers., (Copyright © 2020. Published by Elsevier Inc.)

The fungicide carbendazim (CBM) has been applied all around the world but its potential adverse effects other than its recognized activity as endocrine disruptor in non target organisms have been scarcely studied. The aims of this work were (1) to use a battery of biomarkers that can reflect potential negative effects such as oxidative stress, genotoxicity, neurotoxicity or altered immune response; and (2) to examine biomarkers of detoxification by analyzing the gene expression of cytochrome P4501A1 (CYP1A1) and the multi-xenobiotic resistance protein P-glycoprotein (P-gp) in the freshwater fish Jenynsia multidentata exposed to environmentally relevant concentrations of CBM during 24 h. Fish exposed to 5 μg/L showed inhibition of GST activity and an increase of TBARs contents in gills, the organ of direct contact with waterborne contaminants. Genotoxicity - measured in peripheral blood-was evidenced by the increases of micronuclei frequency when fish were exposed to 5, 10 and 100 μg/L CBM and of nuclear abnormalities (NA) frequency at 0.05, 0.5, 5, 10 and 100 μg/L CBM. The expression inhibition of interleukin (IL-1β) and tumor necrosis factor a (TNF-α) at 10, and 5 and 10 μg/L CBM, respectively, indicated an altered immune response. The expression of CYP1A1 was down regulated in liver at 10 μg/L and of P-gp at 5 μg/L CBM, indicating a possible slow on CBM metabolization. On the other hand, in gills CYP1A1 decreased at 5 and 10 μg/L while P-gp was induced at 5 and 100 μg/L CBM. Overall, most of these significant effects were detected below 10 μg/L CBM, in a range of realistic concentrations in aquatic ecosystems worldwide., (Copyright © 2020. Published by Elsevier Inc.)

Polar Organic Chemical Integrative Samplers (POCIS) were deployed in two watersheds in Córdoba province and one watershed in Buenos Aires province in Argentina. The fungicides, tebuconazole, carbendazim and azoxystrobin, and the herbicides, atrazine, dicamba and 2,4-D were detected in POCIS deployed in each of the three watersheds. Estimated time weighted average concentrations of atrazine were greater than 2 µg/L at the outflow of Brava Lake in Buenos Aires province, and this concentration exceeds the Canadian water quality guideline for protection of aquatic life. The concentrations of all other pesticides were less than 400 ng/L. The distribution of pesticides detected in surface waters indicated that the sources were runoff from agricultural and urban lands and discharges from wastewater treatment plants.

Agricultural production in the Pampas region is one of the most important economic activities in Argentina. However, the possible environmental effects related to the growth of this activity in the last years have not been studied enough. Particularly, the effects of pesticides mixtures are a topic of great concern both for society and regulatory authorities worldwide, given the possible additive and synergistic relationships between these chemicals and their possible effects on aquatic biota. Based on a concentration addition model, this study developed an Ecological Risk Assessment (ERA) of pesticides from freshwater ecosystems in the Pampas region. For this purpose, reported pesticides concentrations available in public bibliography and a Risk Quotients (RQs) approach were used. A cumulative risk map was established to display RQs for current use pesticides (CUPs) and legacy chemicals. The ΣRQs were calculated for 66 sites, using available reported measured environmental concentrations (MECs) and predicted no effect concentrations (PNECs) of pesticides. While ΣRQ for only CUPs resulted in a high and very high risk (ΣRQ > 1) for 29% of the sites, when legacy pesticides were incorporated this percentage reached the 41% of the sites, increasing significantly the absolute values of RQ. Herbicides like glyphosate and atrazine contributed considerably to the ΣRQ CUPs while organochlorines were the major contributors for ΣRQs when legacy pesticides were incorporated. Moreover, some active ingredients (acetochlor, carbendazim and fenitrothion) which are approved for their use in Argentina but banned in EU showed high contribution to ΣRQ CUPs . The present study is the first attempt to develop an ERA in surface water of the Pampas region of Argentina and it provides a starting point for a more comprehensive pesticides monitoring and a further risk assessment program., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Global trends in pesticide use can increase aquatic pollution and affect resident fisheries. Crabs exposed to organophosphate pesticides, such as chlorpyrifos, may increase production of reactive oxygen species (ROS), affecting the pro-oxidant/antioxidant balance. Zichiopsis collastinensis crabs were exposed to environmentally relevant concentrations of chlorpyrifos (0.1 and 0.5 µg L -1 ). Effects on the oxidative stress enzymes catalase, superoxide dismutase, glutathione S-transferases, glutathione reductase, and on thiobarbituric acid reactive substances and hydrogen peroxide concentrations were evaluated at four intervals during 96 h exposures. Exposures caused decreased GST activity and increased H 2 O 2 levels in gills. There were modifications of GST, CAT and SOD activities in the hepatopancreas after 12 h of exposure, and an increase of H 2 O 2 levels at every exposure interval observed. The present study proved that chlorpyrifos lead to oxidative stress in Z. collastinensis. However other enzymatic/non-enzymatic responses should be further investigated in order to be included as part of a battery of biomarkers, together with H 2 O 2 levels, which is a parameter highly recommended to be taken into account.

Imidacloprid (IMI) is a neonicotinoid insecticide widely used in agricultural activities all around the world. This compound is transported from croplands to surrounding freshwater ecosystems, producing adverse effects on non-target organisms. Because of the relevance of aquatic macrophytes in the above-mentioned environments and the lack of studies of potential effects of IMI on them, this work aimed to assess the mitotic process and potential genotoxicity in the aquatic macrophyte Bidens laevis L. Although the analysis of the Mitotic Index (MI) showed that IMI was not cytotoxic, the Cell Proliferation Kinetics (CPK) frequencies evidenced modifications in the kinetics of the mitotic process. Indeed, the anaphases ratio decreased at 10 and 100 μg/L IMI, while at 1000 μg/L an increase of prophases ratio and a decrease of metaphases ratio were observed. Regarding genotoxicity, IMI produced an increase of the abnormal metaphases frequency from 10 μg/L to 1000 μg/L as well as an increase in clastogenic anaphases-telophases frequency at 100 and 1000 μg/L. In addition, aneugenic anaphases-telophases and C-mitosis frequencies also increased at 1000 μg/L, confirming the effects on the mitotic spindle. Considering the genotoxic effects on B. laevis through two different mechanisms (aneugenic and clastogenic) and the wide spread use of IMI in agriculture, these mechanisms of toxicity on macrophytes should be considered among other recognized effects of this insecticide on aquatic biota.

The fungicide tebuconazole (TBZ) has been used to prevent terrestrial fungi in agroecosystems, but it can also induce negative effects to non-targeted aquatic organisms, such as plants. The aim of the present work was to evaluate the potential cyto- and genotoxicity of TBZ in the aquatic macrophyte Bidens laevis, exposed to a range of concentrations of 0.1-100 µg/L. Mitosis in root tips were analyzed showing decreased mitotic index and an increase of chromosomal aberrations at 10 and 100 µg/L. The regression of TBZ concentration vs. aneugenic aberrations was significant, indicating the mechanism of genotoxicity. The specific growth rate (Gr) for total length decreased in plants exposed to 0.1, 10 and 100 µg/L. Gr for root decreased in plants exposed at 0.1 and 10 µg/L, reaching a maximum percent inhibition root growth rate (Ir) of 68.8%. These results show that TBZ resulted cyto- and genotoxic to B. laevis at environmentally relevant levels.

Azoxystrobin is a strobilurin of growing concern in aquatic environments because it is the most sold fungicide worldwide, however, the information available about its effect on aquatic non-target organisms is scarce. The objective of the present study was to evaluate potential physiological, biochemical, and genetic effects at environmentally relevant (1-10 μg/L) and elevated (100-500 μg/L) concentrations in the aquatic macrophyte Myriophyllum quitense exposed to the commercial formulation AMISTAR ® . Following an acute 24-h exposure, there were no effects of AMISTAR ® on photosynthetic pigments at any of the concentrations evaluated. Glutathione-S-transferase activity was significantly elevated at 1 and 10 μg/L AZX. Significant decrease of catalase and guaiacol peroxidase activities in plants exposed to 500 μg/L, and to 100 and 500 μg/L, respectively, and an increase in glycolate oxidase activity at 500 μg/L was observed. DNA damage at 100 and 500 μg/L was observed. These data indicate that although environmentally relevant levels of AMISTAR ® did not result cytotoxic, this fungicide was genotoxic, affecting the physiological process of photorespiration and caused oxidative damage at high concentrations. In this sense, it is necessary to explore sub-lethal responses in non-target organisms because some effects could promote further potential long-term biological consequences in a context of repeated pulses of exposure.

The RT-qPCR has been the method used to analyze gene expression in plants but its benefits have not been completely exploited in the field of plants ecotoxicology when used as molecular biomarkers. The correct use of RT-qPCR demands to establish a certain number of reference genes (RG) which are expected to be invariable in their expression although it does not always happen. The main goals of this work were to: (1) analyze the stability of six potential RG, (2) establish the optimum number of RG, (3) select the most suitable RG to be applied in Bidens laevis under different test conditions and tissues and (4) confirm its convenience by normalizing the expression of one gene of interest under three different challenges. When all data were pooled together, the geNorm algorithm pointed out beta-actin and beta-tubulin (TUB) as the optimal RG pair while NormFinder algorithm selected nicotinamide adenine dinucleotide dehydrogenase (NADHD) and histone 3 (H3) as possessing the most invariable levels of expression. On the other hand, when data were grouped by tissues, ANOVA test selected H3 and TUB, while data grouped by conditions indicated that H3 and NADHD were the most stable RG under this analysis. Therefore, for a general-purpose set of RG, the overall analysis showed that a set of three RG would be optimum, and H3, TUB and NADHD were the selected ones. On the other hand, as RG can vary depending on the tissues or conditions, results achieved with ANOVA would be more reliable. Thus, appropriate normalization process would clearly need more than one RG.

Endosulfan (ES) modifies the ultrastructure of skeletal muscle fibers and causes changes to the swimming behavior of fish. The objectives of the present work were to evaluate, in fishes of Australoheros facetus, 1) the integrity of myofibrils (Mf) by the analysis of SDS-PAGE profiles, and 2) the functionality of Mf through the microscopically monitoring of the contraction and changes in Mg 2+ Ca 2+ - ATPase and Mg 2+ (EGTA) -ATPase activities. As expected, after the addition of the contraction buffer, control fish Mf contracted. On the contrary, Mf from fish exposed at 0.5 μg/L ES showed a partial contraction and none of the fish exposed at 10 μg/L ES contracted. As judged by its high Mg 2+ Ca 2+ ATPase activity and low Mg 2+ (EGTA) ATPase activity, control Mf showed good functionality. In Mf from fish exposed to 0.5 and 10 μg/L ES the activities of these enzymes were similar, suggesting denaturation or degradation of some component of tropomyosin-troponin complex. SDS-PAGE patterns of Mf from fish exposed to ES showed degradation of the myosin heavy chain and of tropomyosin. Similar values of lipid peroxidation (TBARS) were found in both control and exposed Mf, suggesting that lipid oxidation was not be related to the above-mentioned changes. The observed effects expand the knowledge of ES action in muscles and could be used as biomarkers of damage in fishes exposed to organochlorine compounds like the insecticide endosulfan., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Neonicotinoids are one of the most widely used insecticides in the world. DNA damage is considered an early biological effect which could lead to reproductive and carcinogenic effects. The present study aimed to evaluate DNA damage and bases oxidation as a mechanism of genotoxicity, on the freshwater fish Australoheros facetus acutely exposed to imidacloprid (IMI). The Comet assay with the nuclease ENDO III enzyme was performed for detecting pyrimidine bases oxidation using blood samples. Micronucleus and other nuclear abnormalities frequencies were also quantified. A significant increase of damage index at 100 and 1000 µg/L IMI was detected; while ENDO III score increased from 1 to 1000 µg/L IMI; varying both in a linear concentration-response manner. MN frequency increased in fish exposed to 1000 µg/L IMI. These results show that short-term exposures to environmentally relevant concentrations of IMI could affect the genetic integrity of fishes through oxidative damage.

In the present study, we evaluated the spatial and temporal trends of current-use pesticides in surface water and sediments as well as their relationship with hydrological stream dynamics within the agricultural watershed of El Crespo stream (Buenos Aires Province, Argentina). We sampled 2 contrasting sites: site 1 (upstream), surrounded by agricultural lands, and site 2 (downstream), surrounded by natural grasslands. Most of the applied pesticides (glyphosate, 2,4-D, atrazine, tebuconazole, and imidacloprid) were detected at high frequencies in surface water samples at both sites. However, only glyphosate and aminomethylphosphonic acid (AMPA) were present at high concentrations and had a significant spatial-temporal trend. The highest concentrations were found during spring 2014 at site 1, in association with the intense rains that occurred in that season. The fact that glyphosate and AMPA concentrations were higher than the rest of the studied compounds is closely related to the land use within the watershed, as glyphosate was the most applied herbicide during the fallow period of glyphosate-resistant crops (soybean, maize). The pesticide mixture had a significant spatial-temporal trend, reaching the highest levels during storm flow events in spring 2014. The intensive rains in spring 2014 could be the main factor influencing stream hydrology and pesticide behavior at El Crespo watershed. The estimated annual pesticide losses were 3.11 g/ha at site 1 and 0.72 g/ha at site 2. This result indicates that an attenuation process could be decreasing pesticide loads during downstream transport from site 1 to site 2. Environ Toxicol Chem 2017;36:3206-3216. © 2017 SETAC., (© 2017 SETAC.)

Glyphosate is intensively used in agricultural fields and it is frequently detected in non-target wetland ecosystems. The floating hydrophyte Ludwigia peploides is widely distributed in American streams and it is an abundant species. Therefore, our objectives were (1) to establish and validate an extraction and quantification methodology for glyphosate in L. peploides and (2) to evaluate the role of this species as a potential glyphosate biomonitor in an agricultural watershed. We developed a new method of glyphosate extraction from leaves of L. peploides. The method recovery was 117± 20% and the matrix effect 20%. To validate the method using environmental samples, plants of L. peploides were collected in March 2016 from eight monitoring sites of El Crespo stream. Surface water and sediment samples were collected at the same time to measure glyphosate and to calculate bioconcentration factors (BCFs) and biota-sediment accumulation factors (BSAFs). Glyphosate was detected in 94.11% in leaves, the concentrations ranging between 4 and 108 μg/kg. Glyphosate was detected in surface water and sediments at 75% and 100% of the samples, at concentrations that varied between 0 and 1.7 μg/L and 5-10.50 μg/kg dry weight, respectively. The mean BCFs and BSAFs were 88.10 L/Kg and 7.61, respectively. These results indicate that L. peploides bioaccumulates glyphosate mainly bioavailable in the surface water. In this sense, L. peploides could be used as a biomonitor organism to evaluate glyphosate levels in freshwater aquatic ecosystems because, in addition to its capacity to bioconcentrate glyphosate, it is easy to sample and it has a restricted mobility., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The neonicotinoid imidacloprid is under re-evaluation by regulatory agencies because of the poor current information available regarding its potential effects. One of the goals of the present study was to determine imidacloprid uptake and distribution in the freshwater fish Australoheros facetus experimentally exposed for 24 h and 48 h to 100 μg/L, 300 μg/L, and 2500 μg/L. The toxicity of imidacloprid to fish reported in the literature is in the milligrams per liter or gram per liter range, but sublethal effects at micrograms per liter in some groups other than fish have been described. Another goal of the present study was to evaluate imidacloprid's potential genotoxicity and to compare it between the individual compound and a commercial formulation. Concentrations of imidacloprid were measured in water, brain, muscle, gills, gut, liver, and blood by liquid chromatography-tandem mass spectrometry. Imidacloprid was detected in all the tissues tested. Concentrations were higher after 48 h than after 24 h in liver, gills, gut, and muscle, whereas in brain and blood they were similar at both exposure times. Although there was no accumulation, only uptake, of imidacloprid, genotoxicity was observed. In fish exposed to IMIDA NOVA 35 ® , increased micronucleus frequency at 100 µg/L and 1000 µg/L was detected, whereas in the imidacloprid active ingredient bioassay it increased only at 1000 µg/L imidacloprid. The present findings warn of the possible consequences that fish living in freshwater ecosystems can suffer. Environ Toxicol Chem 2017;36:699-708. © 2016 SETAC., (© 2016 SETAC.)

The massive use of glyphosate (GLY) in several countries has increased the interest in investigating its potential adverse effects in non-target organisms. The aim of the present study was to assess the potential effects in survival and reproduction; avoidance behavior and oxidative stress under short-term (48 h) and subchronic exposures (28 days) to GLY in the earthworm Octolasion cyaneum. After 48 h no significant changes in the behavior was observed. In addition, a lower catalase activity at 498 μg GLY kg(-1) dry soil section relative to earthworms from the control section was obtained. After 28 days of exposure inhibition of glutathione S-transferase activity was observed at 535 μg GLY kg(-1) dry soil while no changes in the other endpoints were detected. These results indicate that environmentally relevant concentrations of GLY (up to 996 µg GLY kg(-1) dry soil) did not exert a toxic effect to O. cyaneum.

Among the search for new types of pesticides, the fungicide azoxystrobin (AZX) was the first patent of the strobilurin compounds, entering in the market in 1996. Its use worldwide is growing, mainly linked to soybean production, although its effects in non-target organisms are almost unknown. The goal of the present work was to evaluate effects of short-term AZX exposure to the aquatic macrophyte Myriophyllum quitense, focusing on oxidative stress parameters and DNA fragmentation. Significant inhibition of the antioxidant enzyme systems were observed at 50 μg/L AZX for catalase and peroxidase (p < 0.05). Lipid and DNA damage were significant at 50 and 100 μg/L AZX. These biomarkers were sensitive to AZX and can be used in a battery to evaluate the occurrence of AZX in freshwater ecosystems.

Previous studies in the wetland macrophyte Bidens laevis L have demonstrated that the insecticide endosulfan induces a high frequency of somatic chromosome aberrations in anaphase-telophase (CAAT) but no DNA changes as determined by the single cell gel electrophoresis (Comet) assay. Thus, cytogenetic biomarkers appear to be more sensitive to the toxic effects of the insecticide than the DNA molecule in the studied species. For this reason, the goals of this study were to use cytogenetic biomarkers--CAAT and abnormal metaphase--and defense biomarkers such as the activity of the antioxidant enzymes--guaiacol peroxidases (POD), glutathione reductase, and microsomal and cytosolic (m- and c-) glutathione-S-transferase (GST)--to evaluate in B. laevis effects caused by a commercial formulation of endosulfan. The frequency of CAAT was increased at 5, 10, 50, and 100 μg/L endosulfan with respect to the negative controls by 3.1, 2.5, 2.5, and 3.2-fold, respectively while the frequency of abnormal metaphases was also increased at the same concentrations by 3.5, 2.8, 3.2, and 11.3-fold, respectively. In addition to these aneugenic effects, other abnormalities such as C-mitosis and chromosome clumping were observed at 10 μg/L endosulfan. On the other hand, POD induction at 0.02, 0.5, 5, and 10 μg/L and m-GST inhibition at 0.5, 10, and 50 μg/L in plants exposed during 24 h to endosulfan were observed but all of these responses were highly variable. In conclusion, only cytogenetic biomarkers like CAAT in B. laevis can serve potentially as early warning systems to detect environmentally relevant concentrations of endosulfan in aquatic ecosystems., (Copyright © 2013 Wiley Periodicals, Inc., a Wiley company.)

Endosulfan is genotoxic in somatic cells of Bidens laevis, and reproduction could be affected if translocated from roots to flower buds. Hydroponic experiments were conducted to quantify this transfer. While the root uptake of [(14) C] endosulfan and its transfer to aboveground tissues was relatively low, the resulting average flower bud concentration (1.01 ± 0.76 ng/g) after 30 d of exposure to an aqueous concentration of 5 μg/L could still represent a genotoxic risk for germ cells., (© 2013 SETAC.)

The wetland macrophyte Bidens laevis possesses suitable cytological characteristics for genotoxicity testing. To test its sensitivity as compared to terrestrial plants species currently in use in standardized assays, Methyl Methanesulfonate (MMS), N-ethyl-N-nitrosourea (ENU) and Maleic Hydrazide (HM) were used. On the other hand, the insecticide Endosulfan (ES)--an environmentally relevant contaminant--was assayed in seeds and two-month old plants. Mitotic Index (MI), frequency of Chromosome Aberrations in Anaphase-Telophase (CAAT) and frequency of Abnormal Metaphases (AM) were analyzed. MH, MMS and ENU caused a significant decrease of the MI. MMS was aneugenic whereas MH and ENU were both aneugenic and clastogenic. ES caused a significant concentration-dependent increase of total- and aneugenic-CAAT in roots and a significant high frequency of AM at high concentrations. Because of its sensitivity to mutagenic substances, B. laevis can be regarded as a reliable and convenient species for genotoxicity assays especially if aquatic contaminants are evaluated., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The frequency of micronuclei (MN) and chromosome aberrations in anaphase-telophase (CAAT) was determined in root tips of the wetland macrophyte Bidens laevis exposed to environmentally relevant concentrations of endosulfan (0.01, 0.02, 0.5 and 5microg/L) for 48h. MN frequency varied from 0 in negative controls and plants exposed to 0.01microg/L endosulfan to 0-3 in plants exposed to 5microg/L. Moreover, a significant concentration-dependent increase of CAAT was observed. The higher proportion of laggards and vagrand chromosomes observed at 5microg/L would indicate that endosulfan interacts with the spindle interrupting normal chromosome migration. Endosulfan resulted genotoxic to B. laevis, a species of potential value for bioassays and in situ monitoring of environmental contamination by pesticides.

Endosulfan (1) is a chlorinated insecticide still in use in both developed and emerging countries. Although its toxicity on animals has been studied in the last years, scarce information is available on its effects on plants. In this study, we exposed the aquatic macrophyte Myriophyllum quitense to environmentally relevant concentrations of endosulfan (microg/L) (1) for a short time, simulating exposures that might occur after either accidental spills or toxic run-off from agricultural areas. The main goal was to evaluate changes in both detoxication and antioxidant enzymatic systems of this plant upon exposure to endosulfan (1). Thus, we measured the activities of catalase (CAT), soluble and membrane associated glutathione-S-transferases (s- and m-GSTs) and glutathione reductase (GR), as well as the hydrogen peroxide (H2O2) content. Results showed that endosulfan (1) exerts oxidative stress on M. quitense, which was evidenced by the increase of CAT activity and the H2O2 content in exposed plants. At 5 microg/L endosulfan (1), we found a generalized induction of activities of tested enzymes, indicating that this xenobiotic activates the protection system of this plant, increasing its capacity to scavenge reactive oxygen species. On the other hand, we did not find significant changes at 0.02 microg/L endosulfan (1), which is the maximal concentration allowed for freshwater. We conclude that runoff events, which can produce significant amounts of endosulfan (1) in aquatic environments during short time, can result in oxidative stress on M. quitense, and probably on similar macrophytes.

The influence of intertidal crab beds on the concentrations of organochlorine (OC) pesticides in sediment was studied in two different coastal environments in Argentina. Samples of male burrowing crabs (Chasmagnathus granulatus) were collected for this study. Our field data showed lower bioaccumulation of OC pesticides in crabs from sediments with a higher total organic carbon (TOC) and higher clay content. Thus, concentrations in crabs depend on the physico-chemical characteristics of the sediment where they live more than on the OC pesticide concentrations in the environment. The distribution patterns in sediment from inside and outside crab burrows were similar for both coastal areas being HCHs > or = gamma-chlordane > p,p'-DDE for San Antonio Bay (SAO), and HCHs > p,p'-DDE > or = gamma-chlordane for Mar Chiquita (MCh) coastal lagoon. OC pesticide concentrations in sediment were significantly lower inside than outside crab burrows, irrespective of the sediment physico-chemical characteristics due to the bioturbation activity of C. granulatus.

The general goal of this study was to investigate the role of Cynoscion guatucupa as a biomonitor of organochlorine pesticides (OCP) contamination in Bahía Blanca estuary. Thus, we evaluated whether or not OCP fish distribution pattern reflects the OCP land sources, and if size-related bioaccumulation and biomagnification of these contaminants does occur by comparing different tissues of juvenile and adults of C. guatucupa (Cuvier, 1830). Size-related bioaccumulation in C. guatucupa was observed and it was more important for the more lipophilic and biomagnifying OCP, being determined over time by diet influence. Endosulfan sulfate, chlordanes, HCH isomers and DDT compounds predominated in tissues and ingested food of C. guatucupa, being alpha-chlordane, heptachlor and p,p'-DDE highly bioaccumulated and biomagnificated. Our findings also showed that male adults of C. guatucupa are biomonitors of OCP pollution so we propose this species for further investigations in other coastal zones of South America.

Organic contaminants of environmental concern such as polychlorinated biphenyls have dispersed widely throughout the ecosystems and accumulate in living organisms, and a variety of adverse biological effects have been reported. In this study, we investigated the effects of 3-chlorobiphenyl in the aquatic macrophyte Ceratophyllum demersum and the capacity of its detoxication system. After 24 h of exposure to various concentrations of 3-chlorobiphenyl, the total glutathione content (tGSH) was determined and the dose-response curves for glutathione reductase (GR) and microsomal/cytosolic glutathione S-transferases (m- and c-GSTs, respectively) were established. C. demersum showed a decrease of photosynthesis after exposure to 3-chlorobiphenyl, although only significantly at 5 microgl(-1). At 0.005 and 0.05 microgl(-1) the GR, m-GST and c-GST activities were significantly increased and concomitantly a non-significant effect on total GSH was observed. At 0.5 microgl(-1), GR as well as c-GST were still significantly induced, while at 5 microgl(-1) none of the enzymes were activated. These results show that detoxication through glutathione conjugation takes place at low concentrations of 3-chlorobiphenyl, while concentrations in the order of parts per billion cause the inactivation of the enzymatic systems evaluated, enough to place C. demersum in an important physiological stress condition.

The effect of crab beds and bioturbation activity of the SW Atlantic intertidal crab Chasmagnathus granulata on the organochlorine pesticide (OCP) concentrations in Bahía Blanca estuary, Argentina were studied. Total OCP concentration was significantly lower inside than outside the crab burrows. Nevertheless, the concentrations from outside the crab beds were lower than from outside crab burrows, which indicated that crab beds act as sinks of sediment-bound OCP due to the bioturbation activities of the crabs. The same distribution patterns were found in all sediments as well as in crabs, being cyclodienes>HCHs>DDTs, although large amounts of metabolites rather than the respective parental were found in the organism showing the capacity of C. granulata for metabolising parental compounds. These more water-soluble compounds are excreted by the faeces and finally removed by tidal flushing to the sea. Our results suggest that crabs when present play a role in the distribution of sediment-bound OCP and the crab beds are modifiers of the dynamic of organic pollutants in estuarine areas.

There recently have been increasing interest in South America on organic pollutants from the coastal marine environment. This study intended to seek out the occurrence and distribution of persistent organochlorine compounds in the Mar Chiquita coastal lagoon watershed. The levels were measured in sediments and associated crabs. Though a significant number of PCBs (mainly penta- and hexachlorinated congeners) were detected, the concentrations were very low (in the order of ppbs), indicative of an estuarine environment with little industrial development. On the other hand, pesticide residues were higher than PCBs in one or two orders of magnitude, as a result of the important agricultural activities in the area. Heptachlor epoxide, DDT and its metabolites, and gamma-HCH were the predominant OC pesticides in sediments as well as in crabs. Significant differences among geographical areas: Channel 5 and Vivoratá Creek (northern and southern sampling sites, respectively) contained detectable pesticide concentrations (heptachlor epoxide, DDE, DDD, and mirex).

A freshwater fish species, silverside (Odontesthes bonariensis) from Mar Chiquita coastal lagoon, Argentina, was analyzed for concentrations of several organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) in liver, gonads, mesenteric fat and muscle, and the contents of the digestive tract over several stages of sexual maturation. PCBs and OCs were detected at ng/g concentrations (wet weight) in pooled samples, with levels generally in the order of fat > liver > gonad > muscle, reflecting the differences in tissue lipid content. Lipid-normalized concentrations of the analytes were relatively consistent among tissues, except for significantly higher concentrations of PCBs (e.g., 447.7 ng/g lipid wt) in the ovaries of female silverside. DDT and its metabolites, gamma-HCH, and several insecticides from the cyclodiene class, including endosulfan and endosulfan sulfate, were the predominant OCs in fish tissues and the contents of the digestive tract, reflecting recent and past pesticide use in this region. The ratio of OCs to PCBs in all tissues was >1; consistent with contamination of the region with OC pesticides. However, PCBs were dominated by penta- and hexachlorobiphenyls, which is consistent with direct (i.e. , nonatmospheric) inputs. Biomagnification of penta- and hexachlorobiphenyl PCB congeners was noted in fish tissues relative to the contents of the digestive tract. Total OC and PCB concentrations in the ovaries and muscle of silverside were below concentrations associated with reproductive impairment in fish or the limits for human consumption, respectively.