Cocktails of pesticide residues in Prochilodus lineatus fish of the Salado River (South America): First record of high concentrations of polar herbicides.

Muscle and viscera (gills-liver) of the fish Prochilodus lineatus were obtained from four sites of lower course of Salado river and one site at Santa Fe river near to its confluence with Salado river from Santa Fe (Argentina) between December 2021 and February 2022. Sediment samples were also obtained from the same sites. All samples were analyzed for pesticide residues following the QuEChERS method to quantify 136 compounds by UHPLC-ESI-MS/MS and GC-EI-MS/MS. Overall, muscle fish tissue showed very high concentrations (maximum concentrations detected) of the insecticide cypermethrin (204 µg/kg), polar herbicides (glyphosate; 187 µg/kg and its degradation product (aminomethylphosphonic acid) AMPA; 3116 µg/kg, and glufosinate-ammonium; 677 µg/kg), and the fungicide pyraclostrobin (50 µg/kg). In viscera samples, high values of cypermethrin (506 µg/kg), chlorpyrifos (78 µg/kg), and lambdacyhalothrin (73 µg/kg) were the main pesticides found. Mean residues concentrations detected among sites were not significantly different neither in muscle nor viscera of P. lineatus in most of the cases. Exceptionally, the southernmost studied site of the Lower Salado river showed significant differences in concentration of residues found in muscle, due to high concentrations of glyphosate and glufosinate-amonium (KW = 11.879 and KW = 13.013, respectively, P < 0.05). Other norther Lower Salado river site showed significant higher AMPA concentration in fish viscera than in the rest of the studied sites (KW = 12.86 P < 0.05). Some sediment samples showed low levels of herbicides such as glyphosate (24 µg/kg) and fungicides. However, the world highest levels of polar herbicides were recorded in fish muscle. The results of this study highlight the need for periodic monitoring due to the high concentration of pesticides and its potential risk in a very important commercial freshwater fish from Argentina, which is consumed locally and exported to other countries for human consumption.

Comparative assessment of individual and mixture chronic toxicity of glyphosate and glufosinate ammonium on amphibian tadpoles: A multibiomarker approach.

The aim of the present study was to assess the ecotoxicity of glyphosate and glufosinate ammonium mixtures on amphibian tadpoles and the potential impact of mixture in aquatic ecosystems health. The bonding properties of the mixture based on computational chemistry and an experimental bioassay on morphology, DNA damage and biochemical biomarkers on tadpoles of the common toad Rhinella arenarum were studied. The results of the density functional theory analysis showed trends of the pesticides clustering to form exothermic mixtures, suggesting the likelihood of hot-spots of pesticides in real aquatic systems. In addition, biological effects of individual pesticides and the mixture were studied on tadpoles over 45 days-chronic bioassay. The bioassay consisted of four treatments: a negative control (CO), 2.5 mg L-1 of a glyphosate-based herbicide (GBH), 2.5 mg L-1 of a glufosinate ammonium-based herbicide (GABH) and their 50:50 (% v/v) mixture (GBH-GABH). Morphological abnormality rates were significantly higher in all herbicide treatments with respect to CO at 48 h of exposure. Abdominal edema was the most frequent type of abnormality recorded at 48 h, 10 and 45 days of exposure. DNA damage was recorded in all herbicides treatments. Thyroxin increased only in GABH treatment. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) significantly increased in GBH treatment, indicating a GBH-neurotoxic effect. Glutathione S-transferase decreased in GABH and GBH-GABH treatments, while catalase decreased in individual GBH and GABH treatments. Overall, teratogenicity, DNA damage, hormonal disruption (T4), and oxidative stress were greater in GABH-treated tadpoles than GBH-treated tadpoles. This study also highlights the robust chemical interaction between the active ingredients of both herbicides, which is reflected on antagonisms in most of analyzed biomarkers, as well as potentiation and additivity in others. Based on our results, the GABH had a higher toxicity than GBH for amphibian tadpoles.

Influence of abiotic factors (water activity and temperature) on growth and aflatoxin production by Aspergillus flavus in a chickpea-based medium.

The effect of water activity (aW; 0.87, 0.90, 0.92, 0.94, 0.96, 0.98 and 0.99), temperature (15, 25, and 30 °C), incubation time (5, 10, 14, and 21 days), and their interactions on mycelial growth and aflatoxin production in a chickpea-based medium by three Aspergillus flavus strains isolated from chickpea grains in Argentina was evaluated. Maximum growth rates were obtained at the highest aW (0.99) and 30 °C, with growth decreasing as the aW of the medium was reduced. Maximum levels of aflatoxins were produced at 0.99 aW and 25 °C after 5 days of incubation for two strains, and at 25 °C and 0.96 aW after 21 days of incubation for the third strain. The aflatoxin concentrations varied considerably depending on the aW and temperature interactions assayed. Two-dimensional profiles of aW by temperature interactions were developed from these data to identify areas where conditions indicate a significant risk from aflatoxin accumulation on chickpea. This study provides useful baseline data on conditions representing a high and a low risk for contamination of chickpea by aflatoxins which is of greater concern because this pulse is destined mainly for human consumption.

Glyphosate and glufosinate ammonium, herbicides commonly used on genetically modified crops, and their interaction with microplastics: Ecotoxicity in anuran tadpoles.

The effects of glyphosate (GLY)-based and glufosinate ammonium (GA)-based herbicides (GBH and GABH, respectively) and polyethylene microplastic particles (PEMPs) on Scinax squalirostris tadpoles were assessed. Tadpoles were exposed to nominal concentrations of both herbicides (from 1.56 to 100 mg L-1) and PEMPs (60 mg L-1), either alone or in combination, and toxicity evaluated at 48 h. Acetylcholinesterase (AChE), carboxylesterase (CbE), and glutathione-S-transferase (GST) activities were analyzed at the three lowest concentrations (1.56, 3.12 and 6.25 mg L-1, survival rates >85%) of both herbicides alone and with PEMPs. Additionally, the thermochemistry of the interactions between the herbicides and polyethylene (PE) was analyzed by Density Functional Theory (DFT). The median-lethal concentration (LC50) was 43.53 mg L-1 for GBH, 38.56 mg L-1 for GBH + PEMPs, 7.69 for GABH, and 6.25 mg L-1 for GABH+PEMPs. The PEMP treatment increased GST but decreased CbE activity, whereas GBH and GABH treatments increased GST but decreased AChE activity. In general, the mixture of herbicides with PEMPs increased the effect observed in the individual treatments: the highest concentration of GBH + PEMPs increased GST activity, whereas GABH+PEMP treatments decreased both AChE and CbE activities. DFT analysis revealed spontaneous interactions between the herbicides and PE, leading to the formation of bonds at the herbicide-PE interface, significantly stronger for GA than for GLY. The experimental and theoretical findings of our study indicate that these interactions may lead to an increase in toxicity when pollutants are together, meaning potential environmental risk of these combinations, especially in the case of GA.

Neonatal exposure to a glyphosate-based herbicide alters the histofunctional differentiation of the ovaries and uterus in lambs.

The aim of the present study was to compare the effect of oral and subcutaneous exposure to a glyphosate-based herbicide (GBH) on the female reproductive system, specifically in the ovaries and uterus of prepubertal lambs. To this end, ewe lambs were exposed to a s.c. (n: 5) or an oral (n: 5) environmentally relevant dose of GBH (2 mg/kg/day) or to vehicle (controls, n: 12), from postnatal day (PND) 1 to PND14. Serum glyphosate and aminomethylphosphonic acid (AMPA) concentrations were measured on PND15 and PND45. The ovaries and uterus were obtained and weighed on PND45. Ovarian follicular dynamics and uterine morphological features were determined by picrosirius-hematoxylin staining. The proliferation marker Ki67 was evaluated by immunohistochemistry in ovarian and uterine samples. Glyphosate but not AMPA was detected in serum of exposed lambs on PND15, whereas neither glyphosate nor AMPA were detected on PND45. Controls were negative for glyphosate and AMPA on PND15 and PND45. GBH exposure did not affect ovarian or uterine weight. However, on PND45, the ovary of GBH-exposed lambs showed altered follicular dynamics, increased proliferation of granulosa and theca cells, and decreased mRNA expression of FSHR and GDF9, whereas their uterus showed decreased cell proliferation but no alterations in the histomorphology or gene expression. In conclusion, GBH exposure altered the ovarian follicular dynamics and gene expression, and the proliferative activity of the ovaries and uterus of lambs. It is noteworthy that all the adverse effects found in the ovaries and uterus of both GBH-exposed groups were similar, independently of the administration route.

Determination of glyphosate, AMPA and glufosinate in dairy farm water from Argentina using a simplified UHPLC-MS/MS method.

Argentina, together with the USA and Brazil, produces approximately 80% of the total worldwide glyphosate loadings. The development of a simplified ultra-high performance liquid chromatographic tandem mass spectrometric method (UHPLC-MS/MS) for the determination of glyphosate, aminomethylphosphonic acid (AMPA) and glufosinate in water is described, including studies of several alternatives of 9-fluorenylmethylchloroformate (FMOC-Cl) derivatization and pretreatment steps. The proposed method includes acidification and neutralization of a low sample volume (3 mL), 2 hours derivatization step, cleanup with dichloromethane, followed by reverse phase UHPLC-MS/MS determination of the analytes. Figures of merit were satisfactory in terms of linearity, selectivity, accuracy and intermediate precision (%REC 70-105% with RSD < 15%). Limits of quantification (LOQ) were suitable for monitoring purposes (0.6, 0.2, 0.1 µg/L for glyphosate, AMPA and glufosinate respectively). The validated methodology was applied for the analysis of livestock wells waters from 40 dairy farms located in the central region of Argentina. Glyphosate and AMPA were quantified in 15% and 53% of the analyzed samples with concentrations ranging from 0.6-11.3 µg/L and 0.2-6.5 µg/L respectively. Greater concentrations of glyphosate were also verified in waters from open-reservoir tanks, which are directly exposed to the farm environment. In these cases glyphosate and AMPA occurrence increased, being quantified in the 33% and 61% of the samples with values ranging 0.6-21.2 µg/L and 0.2-4.2 µg/L respectively. Also in this case glufosinate was found in 52% samples at

Perinatal exposure to a glyphosate-based herbicide impairs female reproductive outcomes and induces second-generation adverse effects in Wistar rats.

Glyphosate-based herbicides (GBHs) are the most globally used herbicides raising the risk of environmental exposition. Here, we investigated whether perinatal exposure to low doses of a GBH alters the female reproductive performance, and/or induced second-generation effects related to congenital anomalies or growth alterations. Pregnant rats (F0) received a GBH through food, in a dose of 2 mg (GBH-LD: GBH-low dose group) or 200 mg (GBH-HD: GBH-high dose group) of glyphosate/kg bw/day from gestational day (GD) 9 until weaning. Body weight gain and vaginal canal-opening of F1 females were recorded. Sexually mature F1 females were mated to evaluate their reproductive performance by assessing the pregnancy rate, and on GD19, the number of corpora lutea, the implantation sites (IS) and resorption sites. To analyze second-generation effects on F2 offspring, we analyzed the fetal morphology on GD19, and assessed the fetal length and weight, and the placental weight. GBH exposure neither altered the body weight gain of F1 females, nor vaginal opening onset. Although all GBH-exposed F1 rats became pregnant, a lower number of IS was detected. F2 offspring from both GBH groups showed delayed growth, evidenced by lower fetal weight and length, associated with a higher incidence of small for gestational age fetuses. In addition, higher placental weight and placental index were found in F2 offspring from GBH-HD dams. Surprisingly, structural congenital anomalies (conjoined fetuses and abnormally developed limbs) were detected in the F2 offspring from GBH-HD group. In conclusion, perinatal exposure to low doses of a GBH impaired female reproductive performance and induced fetal growth retardation and structural congenital anomalies in F2 offspring.

Glyphosate loss by runoff and its relationship with phosphorus fertilization.

The aim of this study was to evaluate the relationship between glyphosate and phosphate fertilizer application and their contribution to surface water runoff contamination. The study was performed in Aquic Argiudoll soil (Tezanos Pinto series). Four treatments were assessed on three dates of rainfall simulation after fertilizer and herbicide application. The soluble phosphorus in runoff water was determined by a colorimetric method. For the determination of glyphosate and aminomethylphosphonic acid (AMPA), a method based on fluorenylmethyloxycarbonyl (FMOC) group derivatization, solid phase extraction (SPE) purification, and ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was employed. The application of phosphorus fertilizer resulted in an increased loss of glyphosate by runoff after 1 day of application. These results suggest the need for further study to understand the interactions and to determine appropriate application timing with the goal of reducing the pollution risk by runoff.