Sorption and mobility assessment of tembotrione in soils of upper, trans and middle Gangetic plain zones of India.

The presence of undesired agrochemicals residues in soil and water poses risks to both human health and the environment. The behavior of pesticides in soil depends both on the physico-chemical properties of pesticides and soil type. This study examined the adsorption-desorption and leaching behavior of the maize herbicide tembotrione in soils of the upper (UGPZ), trans (TGPZ) and middle Gangetic plain zones of India. Soil samples were extracted using acetone followed by partitioning with dichloromethane, whereas liquid-liquid extraction using dichloromethane was used for aqueous samples. Residues of tembotrione and its metabolite TCMBA, {2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy) methyl] benzoic acid}, were quantified using liquid chromatography-tandem mass spectrometry. The data revealed that tembotrione adsorption decreased with increasing pH and dissolved organic matter but increased with salinity. The maximum adsorption occurred at pH 4, 0.01 m sodium citrate and 4 g/L NaCl, with corresponding Freundlich constants of 1.83, 2.28 and 3.32, respectively. The hysteresis index <1 indicated faster adsorption than desorption. Leaching studies under different flow conditions revealed least mobility in UGPZ soil and high mobility in TGPZ soil, consistent with groundwater ubiquity scores of 4.27 and 4.81, respectively. Soil amendments decreased tembotrione mobility in the order: unamended > wheat straw ash > wheat straw > farm yard manure > compost. The transformation of tembotrione to TCMBA and its mobility in soil columns were also assessed.

Assessment of the effects of 2,4-D-dichlorophenoxyacetic acid-based herbicide exposure in eggs and embryos of golden apple snails using OCT.

This study aimed to evaluate the effects of herbicide 2, 4-D-dichlorophenoxy acetic acid on golden apple snail eggs and embryos. Additionally, the study assessed the applicability of optical coherence tomography (OCT), a non-invasive depth cross-sectional microscopic imaging technique, as a novel method, to the best of our knowledge, for studying morphological changes in golden apple snail eggs and embryos, in comparison to the conventional approach of using white light microscopy. The study revealed that the herbicide 2,4-D-dichlorophenoxy acetic acid affected the hatchery rate and morphological changes of the eggs and embryos. The lethal concentration (LC50), representing the concentration of a substance that is expected to cause death in half of the population being studied, of the golden apple eggs and embryos increased with longer exposure time and higher concentrations. The estimated median effective concentration (EC50), which denotes the concentration producing the desired effect in 50% of the exposed golden apple embryos, exhibited a similar trend of change as the LC50. When compared to the microscopic study, it was observed that OCT could be employed to investigate morphological changes of golden apple snail eggs and embryos, enabling evaluation of alterations in both 2D and 3D structures.

Legacy of herbicides in water from Hailun City, Northeast China: Occurrence, source, and ecological risk assessment.

Herbicides (HBCs) are extensively used in modern agriculture. However, their potential negative impacts on environmental media have emerged as a significant environmental concern. In this study, we employed positive matrix factorization (PMF) to identify the potential sources of HBCs. Furthermore, we utilized a multi-matrix ecological risk model to assess the risks associated with HBCs in both surface water and groundwater in the black soil region of Northeast China. The findings revealed that the levels of ∑15HBCs in surface water and groundwater ranged from 585.84 to 6466.96 ng/L and 4.80 to 11,774.64 ng/L, respectively. The PMF results indicated that surface runoff and erosion accounted for 50% of the total HBCs in water, serving as the primary sources. All tested HBCs exhibited acute risk values within acceptable levels. The risk index for the ∑15HBCs was categorized as "moderate risk" in 31% of the surface waters and 13% of the groundwaters. However, 4% of the groundwater sampling sites reached the "high risk" level. The chronic risk quotient of ∑15HBCs in surface water and groundwater was 92% and 62% at the "high risk" level, respectively. Interestingly, non-carcinogenic HBCs contributed more significantly to the ecotoxicology of the aquatic system than carcinogenic HBCs. This study provides comprehensive information on the legacy of HBCs in water bodies and emphasizes the potential risks posed by HBCs to aquatic systems. The results obtained from this study could help relevant management authorities in developing and implementing effective regulations to mitigate the ecological and environmental risks associated with HBCs.

Evaluation of phosphate insecticides and common herbicides: monitoring and risk assessment in water treatment plant, distribution networks, and underground water wells.

Despite the negative effects that the use of pesticides (such as herbicides and insecticides) have on human health and water resources, a significant portion of the world's agricultural production depends on them. The purpose of this study was to determine selected residual concentrations of pesticides (diazinon, ethion, malathion, alachlor, methyl-parathion, trifluralin, atrazine, chlorpyrifos, and azinphos-methyl) in samples from Shiraz potable water sources. For this purpose, water treatment plant, groundwater wells, treated surface water, and a mixture of groundwater and treated surface water were taken. In addition, statistical and risk analyses (carcinogenic and non-carcinogenic) were used. According to the results, chlorpyrifos with 84.4% had the highest removal efficiency and methyl-parathion with 10% had the lowest removal rate in the Shiraz water treatment plant process. The highest mean concentration was related to azinphos-methyl (1.5 µg/L) and chlorpyrifos (0.59 µg/L) in the groundwater samples. All measured compounds in water source samples were below standard levels, except for chlorpyrifos and azinphos-methyl, which were reported in groundwater above the limit recommended by the Environmental Protection Agency (EPA). The results showed that while the selected pesticides measured had a low non-carcinogenic risk for both adults and children, malathion and trifluralin posed a high carcinogenic risk for adults.

Prognostic value of plasma diquat concentration in patients with acute oral diquat poisoning: a retrospective study.

Objectives: Diquat poisoning is an important public health and social security agency. This study aimed to develop a prognostic model and evaluate the prognostic value of plasma diquat concentration in patients with acute oral diquat poisoning, focusing on how its impact changes over time after poisoning. Methods: This was a retrospective cohort study using electronic healthcare reports from the Second Hospital of Hebei Medical University. The study sample included 80 patients with acute oral Diquat poisoning who were admitted to the hospital between January 2019 and May 2022. Time-to-event analyses were performed to assess the risk of all-cause mortality (30 days and 90 days), controlling for demographics, comorbidities, vital signs, and other laboratory measurements. The prognostic value of plasma DQ concentration on admission was assessed by computing the area under a time-dependent receiver operating characteristic curve (ROC). Results: Among the 80 patients, 29 (36.25%) patients died, and 51 (63.75%) patients survived in the hospital. Non-survivors had a median survival time (IQR) of 1.3(1.0) days and the longest survival time of 4.5 days after DQ poisoning. Compared with non-survivors, survivors had significantly lower amounts of ingestion, plasma DQ concentration on admission, lungs injury within 24 h after admission, liver injury within 24 h after admission, kidney injury within 24 h after admission, and CNS injury within 36 h after admission, higher APACHE II score and PSS within 24 h after admission (all p < 0.05). Plasma Diquat concentration at admission (HR = Exp (0.032-0.059 × ln (t))) and PSS within 24 h after admission (HR: 4.470, 95%CI: 1.604 ~ 12.452, p = 0.004) were independent prognostic factors in the time-dependent Cox regression model. Conclusion: Plasma DQ concentration at admission and PSS within 24 h after admission are independent prognostic factors for the in-hospital case fatality rate in patients with acute oral DQ poisoning. The prognostic value of plasma DQ concentration decreased with time.

Glyphosate contamination of drinking water and the occurrence of oxidative stress: Exposure assessment to rural Brazilian populations.

Studies reported that continuous application of glyphosate can cause disturbance in aquatic/terrestrial environments. As such, the objective of this study is to discuss the risk of exposure to the herbicide in drinking water and to assess the oxidative stress in the consumers rural populations of Casimiro de Abreu/ RJ and Paraguaçu/ MG, Brazil. For this, water samples (n=69) were analysed from the home of volunteers, by FMOC derivatizing- LC-FLD method. The oxidative stress was analysed determining lipid peroxidation (MAD) and defense enzymes (SOD and CAT) in serum samples from rural population (n=42) compared to urban residents (n= 42). Results of the analysis from drinking water, despite the low and moderate risk, by the hazard quotient (HQ), revealed that the population is environmentally exposed to the glyphosate. The relevant findings showed that is important to implement monitoring/ biomonitoring programs to prevent pollution and toxic effects in the rural populations.

Unraveling paraquat-induced toxicity on mouse neural stem cells: Dose-response metabolomics insights and identification of sensitive biomarkers for risk assessment.

Exposure to pesticide could contribute to neurodevelopmental and neurodegenerative disorders. Notably, research suggests that prenatal or early postnatal exposure to paraquat (PQ), an herbicide, might trigger neurodevelopmental toxicity in neural stem cells (NSCs) via oxidative stress. However, the molecular mechanisms of PQ-induced perturbations in NSCs, particularly at the metabolite level, are not fully understood. Using a dose-response metabolomics approach, we examined metabolic changes in murine NSCs exposed to different PQ doses (0, 10, 20, 40 µM) for 24h. At 20 µM, PQ treatment led to significant metabolic alterations, highlighting unique toxic mechanisms. Metabolic perturbations, mainly affecting amino acid metabolism pathways (e.g., phenylalanine, tyrosine, arginine, tryptophan, and pyrimidine metabolism), were associated with oxidative stress, mitochondrial dysfunction, and cell cycle dysregulation. Dose-response models were used to identify potential biomarkers (e.g., Putrescine, L-arginine, ornithine, L-histidine, N-acetyl-L-phenylalanine, thymidine) reflecting early damage from low-dose PQ exposure. These biomarkers could be used as points of departure (PoD) for characterizing PQ exposure hazard in risk assessment. Our study offers insights into mechanisms and risk assessment related to PQ-induced neurotoxicity in NSCs.

Metabolism-based category formation for the prioritisation of genotoxicity hazard assessment for plant protection product residues (Part 4): α-Chloroacetamides.

In dietary risk assessment of plant protection products, residues of active ingredients and their metabolites need to be evaluated for their genotoxic potential. The European Food Safety Authority recommend a tiered approach focussing assessment and testing on classes of similar chemicals. To characterise similarity, in terms of metabolism, a metabolic similarity profiling scheme has been developed from an analysis of 69 α-chloroacetamide herbicides for which either Ames, chromosomal aberration or micronucleus test results are publicly available. A set of structural space alerts were defined, each linked to a key metabolic transformation present in the α-chloroacetamide metabolic space. The structural space alerts were combined with covalent chemistry profiling to develop categories suitable for chemical prioritisation via read-across. The method is a robust and reproducible approach to such read-across predictions, with the potential to reduce unnecessary testing. The key challenge in the approach was identified as being the need for metabolism data individual groups of plant protection products as the basis for the development of the structural space alerts.

Occurrence and risk assessment of pesticides and their transformation products related to olive groves in surface waters of the Guadalquivir river basin.

Pesticides are considered one of the main sources of contamination of surface waters, especially in rural areas highly influenced by traditional agricultural practices. The objective of this work was to evaluate the impact caused by pesticides and their transformation products (TPs) related to olive groves in surface waters with strong agricultural pressure. 11 streams were monitored during four sampling campaigns over 2 years. A solid-phase extraction, followed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) analysis was used in the quantitative target approach, with more than 70 validated compounds. Target method was combined with a suspect screening strategy involving more than 500 pesticides and TPs, using ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) to identify additional pesticides and TPs out of the scope of analysis. A total of 43 different compounds were detected with the target method. The herbicide MCPA was present in all samples and at the highest concentration (1260 ng L-1), followed by the fungicide carbendazim (1110 ng L-1), and the herbicide chlorotoluron (706 ng L-1). The suspect screening strategy revealed the presence of 7 compounds out of the target analysis (1 pesticide and 6 TPs). 6 analytes were confirmed with the analytical standards. Semi-quantification results revealed that TPs exhibited higher concentrations than their corresponding parent compounds, indicating higher persistency. Some small streams showed a comparable number of pesticides and concentrations to the most polluted large river. The determined pesticide and TPs concentrations represented an estimated environmental hazard in almost all sampling sites under study. This work underscores the importance of including pesticide TPs and small streams impacted by extensive agricultural activities in water quality monitoring programs.

Investigation of the removal of diclofop methyl herbicide by peroxy electrocoagulation process and kinetic and cost analysis.

Pesticides containing chlorine, which are released during agricultural activities, are chemical substances that mix with surface and underground waters and have toxic, carcinogenic, and mutagenic effects on the entire living ecosystem. Due to their chemically stable structure, conventional water and wastewater treatment techniques such as coagulation, flocculation, and biological oxidation do not entirely remove these chemical substances. Therefore, before releasing them into the environmental receptor, these chemical substances must be transformed into harmless products or mineralized through advanced oxidation processes. When we look at the literature, there are not many studies on methods of removing diclofop methyl from aquatic media. Our study on the removal of diclofop methyl herbicide from aquatic media using the peroxy electrocoagulation method will provide the first information on this subject in the literature. In addition, this treatment method will contribute significantly to filling an important gap in the literature as an innovative approach for diclofop methyl removal. Moreover, peroxy electrocoagulation, which produces less sludge, provides treatment in a short time, and is economical, has been determined to be an advantageous process. The effects of conductivity, pH, H2O2 concentration, current, and time parameters on the removal of diclofop methyl were investigated using a GC-MS instrument. Kinetics, energy consumption, and cost calculations were also made. Under the optimum conditions determined (pH = 5, H2O2 = 500 mg/L, NaCl = 0.75 g/L, current density = 2.66 mA/cm2), the peroxydic electrocoagulation process resulted in a diclofop methyl removal efficiency of 79.2% after a 25-min reaction. When the experimental results were analyzed, it was found that the results fitted the pseudo-second-order kinetic model.

Environmental impact assessment of the electrokinetic adsorption barriers to remove different herbicides from agricultural soils.

In this study, the sustainability of the electrokinetic remediation soil flushing (EKSFs) process integrated without and with adsorption barriers (EKABs) have been evaluated for the treatment of four soils contaminated with Atrazine, Oxyfluorfen, Chlorosulfuron and 2,4-D. To this purpose, the environmental effects of both procedures (EKSFs and EKABs) have been determined through a life cycle assessment (LCA). SimaPro 9.3.0.3 was used as software tool and Ecoinvent 3.3 as data base to carry out the inventory of the equipment of each remediation setup based on experimental measurements. The environmental burden was quantified using the AWARE, USEtox, IPPC, and ReCiPe methods into 3 Endpoint impact categories (and damage to human health, ecosystem and resources) and 7 Midpoints impact categories (water footprint, global warming potential, ozone depletion, human toxicity (cancer and human non-cancer), freshwater ecotoxicity and terrestrial ecotoxicity). In general terms, the energy applied to treatment (using the Spanish energy mix) was the parameter with the greatest influence on the carbon footprint, ozone layer depletion and water footprint accounting for around 70 % of the overall impact contribution. On the other hand, from the point of view of human toxicity and freshwater ecotoxicity of soil treatments with 32 mg kg-1 of the different pesticides, the EKSF treatment is recommended for soils with Chlorosulfuron. In this case, the carbon footprint and water footprint reached values around 0.36 kg of CO2 and 114 L of water per kg of dry soil, respectively. Finally, a sensitivity analysis was performed assuming different scenarios.

[Effects of Pesticides Use on Pesticides Residues and Its Environmental Risk Assessment in Xingkai Lake（China）].

Xingkai Lake, located in Heilongjiang Province, is an important fishery and agricultural base and is seriously polluted by agricultural non-point sources. To clarify the residual status of many pesticides in the surface water of Xingkai Lake, 27 types of pesticides, herbicides, and their degradation products were analyzed in rice paddy, drainage, and surface water around Xingkai Lake (China) during the rice heading and maturity periods. The results showed that all 27 types of pesticides, herbicides, and their degradation products were detected during the rice heading period, and the total concentration ranged from 247.97 to 6 094.49 ng·L-1. Additionally, 25 species were detected during the rice maturity period, and the total concentration ranged from 485.36 to 796.23 ng·L-1. In comparison, more pesticides, herbicides, and derived degradation products were detected during the heading period, and their total concentration was higher as well. During the rice heading period, atrazine, simetryn, and paclobutrazol were the main detected pesticides, atrazine and isoprothiolane were the main pesticides detected during the maturity period. The distribution characteristics of pesticides and herbicides in the surface water around Xingkai Lake (China) was similar to that in drainage, so they were probably imported from the drainage and rice paddy. The average risk quotient (RQ) values of atrazine, simetryn, prometryn, butachlor, isoprothiolane, and oxadiazon were higher than 0.1 in drainage and Xingkai Lake (China), which showed a potential risk to aquatic organisms.

Toxicological assessment of bromoxynil and 2-methyl-4-chlorophenoxyacetic acid herbicide in combination on Cirrhinus mrigala using multiple biomarker approach.

The widespread application of herbicides raises concerns about their impact on non-target aquatic organisms. This study aimed to evaluate the toxicity of a commercially available herbicide formulation containing Bromoxynil+MCPA (2-Methyl-4-chlorophenoxyacetic acid) on Cirrhinus mrigala (economically significant fish). A total of 210 juvenile fish were subjected to a triplicate experimental setup, with 70 fish allocated to each replicate, exposed to seven different concentrations of herbicide: 0 mg/L, 0.133 mg/L, 0.266 mg/L, 0.4 mg/L, 0.5 mg/L, 0.66 mg/L, and 0.8 mg/L, respectively, for a duration of 96 h. The median lethal concentration (LC50) was determined to be 0.4 mg/L. Significant hematological alterations were observed, including decreases in RBC counts, hemoglobin, hematocrit, and lymphocyte counts, along with an increase in erythrocyte indices. Biochemical analysis revealed elevated levels of neutrophils, WBCs, bilirubin, urea, creatinine, ALT, AST, ALP, and glucose in treated groups. Morphological abnormalities in erythrocytes and histopathological changes in gills, liver, and kidneys were noted. Pathological alterations in gills, liver and kidneys including epithelial cell uplifting, lamellar fusion, hepatolysis, and renal tubule degeneration were observed. Oxidative stress biomarkers such as TBARS (Thiobarbituric Acid Reactive Substance), ROS (Reactive Oxygen Species), and POD (Peroxides) activity increased, while antioxidant enzymatic activities decreased as toxicant doses increased from low to high concentrations. The study reveals that Bromoxynil+MCPA significantly disrupts physiological and hematobiochemical parameters in Cirrhinus mrigala, which highlights the substantial aquatic risks. In conclusion, the herbicide formulation induced significant alterations in various fish biomarkers, emphasizing their pivotal role in assessing the environmental impact of toxicity. This multi-biomarker approach offers valuable insights regarding the toxicological effects, thereby contributing substantially to the comprehensive evaluation of environmental hazards.

Acting pre-emptively reduces the long-term costs of managing herbicide resistance.

Globally, pesticides improve crop yields but at great environmental cost, and their overuse has caused resistance. This incurs large financial and production losses but, despite this, very diversified farm management that might delay or prevent resistance is uncommon in intensive farming. We asked farmers to design more diversified cropping strategies aimed at controlling herbicide resistance, and estimated resulting weed densities, profits, and yields compared to prevailing practice. Where resistance is low, it is financially viable to diversify pre-emptively; however, once resistance is high, there are financial and production disincentives to adopting diverse rotations. It is therefore as important to manage resistance before it becomes widespread as it is to control it once present. The diverse rotations targeting high resistance used increased herbicide application frequency and volume, contributing to these rotations' lack of financial viability, and raising concerns about glyphosate resistance. Governments should encourage adoption of diverse rotations in areas without resistance. Where resistance is present, governments may wish to incentivise crop diversification despite the drop in wheat production as it is likely to bring environmental co-benefits. Our research suggests we need long-term, proactive, food security planning and more integrated policy-making across farming, environment, and health arenas.

Herbicide contamination of Batak plain agricultural soils and risk assessment.

Herbicide residue levels were analyzed in agricultural soils of Batak plain and health risk assessments were made for relevant pesticides. Herbicide contamination levels were analyzed with the use of Quick-Easy-Cheap-Efficient-Rugged-Safe (QuEChERS)-liquid chromatography/tandem mass spectrometry (LC-MS/MS) procedure. Herbicide-free soil samples were spiked at two different levels. Overall recovery of the method was 87.32%. Present findings were parallel to SANTE recovery limits. About 50% of collected samples from the study sites contained herbicides at different concentrations. Totally, eight herbicides were detected, and herbicide concentrations ranged between 1.085 and 1724.23 µg kg-1. Metolachlor had the highest concentration (1724.23 µg kg-1) in a sample taken close to the pesticide waste disposal area. Six herbicides were detected at different concentrations in the same sample. Persistent herbicides (terbuthylazine and pendimethalin) were detected in 35 samples. Risk assessments revealed that hazard index (HI) and hazard quotient (HQ) were less than 1. The greatest HQ values were identified for terbuthylazine as 2772.48 × 10-7 and 20793.61 × 10-7 for adults and children, respectively. The HI for all herbicides were 3916.05 × 10-7 for adult and 29370.39 × 10-7 for children.

Research on phytotoxicity assessment and photosynthetic characteristics of nicosulfuron residues on Beta vulgaris L.

Nicosulfuron is a common herbicide used to control weeds in maize fields. In northeast China, sugar beet is often grown as a subsequent crop after maize, and its frequently suffers from soil nicosulfuron residue damage, but the related toxicity evaluation and photosynthetic physiological mechanisms are not clear. Therefore, we experimented to evaluate the impacts of nicosulfuron residues on beet growth, photochemical properties, and antioxidant defense system. The results showed that when the nicosulfuron residue content reached 0.3 µg kg-1, it inhibited the growth of sugar beet. When it reached 36 µg kg-1 (GR50), the growth stagnated. Compared to the control group, a nicosulfuron residue of 36 µg kg-1 significantly decreased beet plant height (70.93 %), leaf area (91.85 %), dry weights of shoot (70.34 %) and root (32.70 %). It also notably reduced the potential photochemical activity (Fv/Fo) by 12.41 %, the light energy absorption performance index (PIabs) by 46.09 %, and light energy absorption (ABS/CSm) by 6.56 %. It decreased the capture (TRo/CSm) by 9.30 % and transferred energy (ETo/CSm) by 16.13 % per unit leaf cross-section while increasing the energy flux of heat dissipation (DIo/CSm) by 22.85 %. This ultimately impaired the photochemical capabilities of PSI and PSII, leading to a reduction in photosynthetic performance. Furthermore, nicosulfuron increased malondialdehyde (MDA) content while decreasing superoxide dismutase (SOD) and catalase (CAT) activities. In conclusion, this research clarified the toxicity risk level, lethal dose, and harm mechanism of the herbicide nicosulfuron residue. It provides a theoretical foundation for the rational use of herbicides in agricultural production and sugar beet planting management.

Stochastic modelling of pesticide transport to drinking water sources via runoff and resulting human health risk assessment.

A modelling framework was developed to facilitate a probabilistic assessment of health risks posed by pesticide exposure via drinking water due to runoff, with the inclusion of influential site conditions and in-stream processes. A Monte-Carlo based approach was utilised to account for the inherent variability in pesticide and population properties, as well as site and climatic conditions. The framework presented in this study was developed with an ability to integrate different data sources and adapt the model for various scenarios and locations to meet the users' needs. The results from this model can be used by farm advisors and catchment managers to identify lower risk pesticides for use for given soil and site conditions and implement risk mitigation measures to protect water resources. Pesticide concentrations in surface water, and their risk of regulatory threshold exceedances, were simulated for fifteen pesticides in an Irish case study. The predicted concentrations in surface water were then used to quantify the level of health risk posed to Irish adults and children. The analysis indicated that herbicides triclopyr and MCPA occur in the greatest concentrations in surface water, while mecoprop was associated with the highest potential for health risks. The study found that the modelled pesticides posed little risk to human health under current application patterns and climatic conditions in Ireland using international acceptable intake values. A sensitivity study conducted examined the impact seasonal conditions, timing of application, and instream processes, have on the transport of pesticides to drinking water.

Toxicity assessment of commercial herbicide formulations to Eisenia andrei (Bouché, 1972) in oxisols.

The use of long-residual herbicides can have adverse effects on terrestrial ecosystems. This study assessed the acute and chronic toxicity and avoidance behavior of Eisenia andrei earthworms exposed to nominal concentrations of clomazone, indaziflam, and sulfentrazone, using recommended commercial formulations for sugarcane cultivation. The formulations included Gamit® 360 CS (360 g L-1 of the active ingredient - a.i. - clomazone), Boral® 500 SC (500 g L-1 of a.i. sulfentrazone), and Alion® (500 g L-1 of a.i. indaziflam). Boral® 500 SC induced avoidance at concentrations as low as 1 mg kg-1, while Gamit® 360 CS and Alion® exhibited higher avoidance at 50-75 mg kg-1 and 75-100 mg a.i. kg-1, respectively. Reproduction tests showed significant impacts from Gamit® 360 CS (EC50: 0.572 mg kg-1, EC10: 0.2144 mg kg-1) and Boral® 500 SC (EC50: 0.3941 mg kg-1, EC10: 0.134 mg kg-1). Acute toxicity tests indicated moderate toxicity for Gamit® 360 CS (LC50: 184.12 mg kg-1) and Boral® 500 SC (LC50: 1000 mg kg-1). Gamit® 360 CS reduced biomass at all concentrations, while Boral® 500 SC influenced only at higher levels (500 and 1000 mg kg-1). Results suggest significant acute risks with Gamit® 360 CS, while chronic exposure raises concerns for both Gamit® 360 CS and Boral® 500 SC, indicating potential long-term risks. Alion®'s acute effects were inconclusive, but chronic exposure hints at a possible risk. These findings provide crucial insights for environmental agencies establishing protective limits against herbicide exposure to non-target soil invertebrates.

Assessment of oxidative stress biomarkers in the threatened annual killifish Austrolebias charrua exposed to Roundup.

This study aimed to analyze the toxic effects of Roundup Transorb® on the endangered Neotropical annual killifish Austrolebias charrua through the assessment of molecular and biochemical biomarkers. The fish were collected in temporary ponds and exposed to environmentally realistic concentrations of the herbicide (5 mg.L-1 for 96 h). The production of ROS, lipid peroxidation, DNA damage, and membrane fluidity were evaluated in the blood cells by flow cytometry. The mRNA expression of the antioxidant-related genes sod2, cat, gstα, atp1a1, gclc, and ucp1 across the brain, liver, and gills was quantified. The acute exposure of annual killifish to Roundup significantly increased ROS production, lipid peroxidation, and DNA damage in their erythrocytes. Likewise, Roundup Transorb® decreased membrane fluidity in the blood cells of the exposed fish. Gene expression analysis revealed that Roundup exposure alters the relative expression of genes associated with oxidative stress and antioxidant defense. Our results give rise to new insights into adaptive mechanisms of A. charrua in response to Roundup. Since Brazilian annual killifishes strongly risk extinction, this study paves the way for developing novel biotechnologies applied to environmental monitoring and aquatic toxicology assessment.

Herbicide resistance evolution, fitness cost, and the fear of the superweeds.

Despite considerable differences in cropping systems around the globe, chemical weed control is a key tool in conventional agroecosystems, which has led to an increase in herbicide resistance. Although mutations causing resistance are thought to have an adaptation cost in resistant plants compared to the susceptible ones under herbicide-free conditions, such cost may not always express or will express under certain ecological conditions. To ensure that herbicides will keep going as viable instruments in agricultural production, strategies to minimize resistance are needed. Proactive or reactive strategies for weed control should utilize an overall integrated weed management approach by combining as many weed management practices as possible. The term 'superweed' was used initially to describe the phenomenon in which genetically engineered crops would become troublesome weeds and that the genes of interest would spread into related weeds, rendering them problematic, or into wild species, turning them into troublesome weeds. Contrary to the above definition, the use of this term in the literature has often been linked with herbicide resistance, mostly related to the cultivation of genetically engineered crops and the related increase in the use of glyphosate, which rapidly selected resistant weed populations. From a scientific point of view, weeds are better survivors than non-weedy species and cause crop problems because they have several unique traits, e.g., they are aggressive, adapt easily to different environments, produce many seeds, compete strongly with crops, disperse easily, are difficult to control, traits which occur whether weeds are herbicide-resistant or not. We propose that the term 'superweed' should be referred to weeds with resistant populations to several herbicides with diverse modes of action (MOAs).