Agricultural Herbicides Research Articles

Synthesis and Characterizations of Molecularly Imprinted Polymer of Atrazine: Removal of Atrazine from Aqueous Samples

AbstractAtrazine (ATZ) is a widely used triazine herbicide in agriculture, however, it negatively affects the environment and human health. Therefore, a molecularly imprinted polymer (MIP) was employed for the selective removal of ATZ. In this study, MIPs were produced by precipitation polymerization using ATZ as the target molecule, methacrylic acid (MAA), acrylamide (AAm), and 2‐vinylpyridine (2VP) as functional monomers and ethylene glycol dimethacrylate (EGDMA) as cross‐linker, respectively. MIP characterizations were performed using Fourier Infrared spectroscopy (FTIR) and Field Emission Electron Microscopy (FESEM). The batch binding study revealed that MIP (2VP) exhibited the highest rebinding efficiency (88.44 %) among the MIPs. Furthermore, MIP (2VP) was analyzed by Energy‐Dispersive X‐ray spectroscopy (EDX), Brunauer‐Emmett‐Teller (BET) analysis, and thermogravimetric analysis (TGA). Adsorption studies revealed that the optimum conditions for maximum adsorption efficiency were 8 ppm ATZ solution at pH 7, using 0.3 g of MIP (2VP). MIP (2VP) demonstrated higher selectivity towards ATZ than the Ametryn (AME) a competitive interferent, with a relative selectivity coefficient of 2.77. MIP (2VP) successfully removed ATZ from distilled water (95.39 %), tap water (88.16 %) and river water (86.75 %). These findings contributed for the development of MIP for the removal of ATZ, which would be helpful in the protection of ecosystem and human health in future.

Construction of a novel fluorescent probe for sensitive determination of glyphosate in food and imaging living cells.

Glyphosate is a widely used broad-spectrum herbicide in agriculture and horticulture to control a variety of weeds and undesirable plants. However, the excessive use of glyphosate has raised a number of environmental and human health concerns. It is urgent to develop tools to detect glyphosate. Herein, a novel dual-signal probe CCU-Cu2+ was designed and synthesized on the basis of CCU. CCU exhibited excellent selectivity and great sensitivity for Cu2+ which were based on both fluorescence "turn-off" reaction and comparative color visualisation methods. Due to the strong chelating ability of glyphosate on Cu2+, the CCU-Cu2+ complex was applied to glyphosate detection in practical samples. The experimental results in vitro showed that the CCU-Cu2+ complex was highly selective and rapid, with a low detection limit (1.6 μM), and could be recognised by the naked eye in the detection of glyphosate. Based on the excellent properties of the CCU-Cu2+ complex, we also constructed a smartphone-assisted detection sensing system for glyphosate detection, which has the advantages of precision, sensitivity, and high interference immunity. Moreover, the CCU-Cu2+ complex was also successfully employed for exogenous glyphosate imaging in living cells. These characteristics demonstrated that CCU-Cu2+ holds significant potential for detection and imaging of glyphosate in bio-systems.

Effect of Glyphosate Herbicide on the Bacterial Population of Arable Land in Keffi, Nasarawa State, Nigeria

The widespread use of herbicides in agriculture has raised significant concerns regarding their impact on the delicate balance of micro and macro flora and fauna in soil and human health. This study was aimed at effect of glyphosate herbicide on the bacterial population in arable land in Keffi, Topsoil samples were carefully collected from various locations in the Keffi arable land, and the bacteria present were isolated and identified using standard microbiological techniques. The results revealed a stark contrast in bacterial counts between the herbicide-polluted and non-polluted soil samples. In pot A, the bacterial count from the polluted soil was 9.3±1.33 CFU x 106, while the non-polluted soil had a count of 14.32±1.02 CFU x 106. Similarly, in pot B, the polluted soil had a bacterial count of 8.4±0.99 CFU x 106, compared to 13.01±1.54 CFU x 106 in the non-polluted soil. In pot C, the polluted soil had a bacterial count of 6.45±1.01 CFU x 106, while the non-polluted soil had 14.01±1.88 CFU x 106. The bacteria isolated from the different pots were also diverse in their composition. Pot A was dominated by Pseudomonas sp., Priestia sp., and Bacillus sp. (33.3% each), while pot B was dominated by Pseudomonas simiae (66.6%) and Proteus sp. and Bacillus magaterium (33.3% each). Pot C, was dominated by Bacillus sp. (66.6%) and Acinetobacter beijerinckii and Citrobacter sp. (33.3% each). Interestingly, several of the isolated bacteria, including Pseudomonas sp., Proteus sp and Acinetobacter beijerinckii, were able to survive and grow in the presence of the glyphosate herbicide. Pseudomonas sp. isolated from pot A1a exhibited the highest utilization of the herbicide, at 30°C (2.19±0.26 mg/ml) and the lowest at 26°C (1.23±0.11 mg/ml). Similar trends were observed for other isolates, with Proteus sp., Priestia sp., and Bacillus magaterium showing the highest herbicide utilization at 35°C. Pseudomonas simiae isolated from pot A1a demonstrated the highest utilization at pH 7.0 (3.54±0.32 mg/ml), and the lowest at pH 5.0 (1.68±0.57 mg/ml). Additionally, the same isolate showed the highest herbicide utilization after 4 and 5 weeks of incubation (2.08±0.02 mg/ml), and the lowest in week 1 (1.18±0.07 mg/ml). The findings of this comprehensive study clearly demonstrate the detrimental impact of glyphosate herbicide on the bacterial population in the arable land of Keffi, Nasarawa State.

Review and Analysis: Evaluation of the Impacts and Consequences of Using Agricultural Herbicides as Military Chemical Weapons in Second Indochina War

Review and Analysis: Evaluation of the Impacts and Consequences of Using Agricultural Herbicides as Military Chemical Weapons in Second Indochina War

Paraquat Toxicity on Substantia Nigra: Pioneering Insights from an Autopsy Based Pilot Study

Paraquat (N,N′-dimethyl-4,4′-bipyridinium dichloride) is one of the widely used herbicides in Indian agriculture. This compound is at the centre of polemics, involving debates on its effects on sustainable agriculture, potential health risks, and unintended applications. Paraquat (PQ) also gained ill repute globally due to the controversy surrounding its association with Parkinson’s disease [1]. Furthermore, our country witnessed a rise in paraquat-related deaths attributed to its misuse for suicide, prompting a consistent call for proper regulation and a potential ban [2]. Paraquat exerts its toxicity through corrosion and the generation of Reactive Oxygen Species (ROS) causing cytotoxic effects that contribute to multiorgan failure. There is no specific antidote for paraquat (PQ) poisoning, and the lethal toxicity of this substance is responsible for a poor prognosis, even with minimal consumption.

Building a highly efficient Streptomyces super-chassis for secondary metabolite production by reprogramming naturally-evolved multifaceted shifts

Streptomyces has an extensive array of bioactive secondary metabolites (SMs). Nevertheless, devising a framework for the heterologous production of these SMs remains challenging. We here reprogrammed a versatile plug-and-play Streptomyces super-chassis and established a universal pipeline for production of diverse SMs via understanding of the inherent pleiotropic effects of ethanol shock on jadomycin production in Streptomyces venezuelae. We initially identified and characterized a set of multiplex targets (afsQ1, bldD, bldA, and miaA) that contribute to SM (jadomycin) production when subjected to ethanol shock. Subsequently, we developed an ethanol-induced orthogonal amplification system (EOAS), enabling dynamic and precise control over targets. Ultimately, we integrated these multiplex targets into functional units governed by the EOAS, generating a universal and plug-and-play Streptomyces super-chassis. In addition to achieving the unprecedented titer and yield of jadomycin B, we also evidenced the potential of this super-chassis for production of diverse heterologous SMs, including antibiotic oxytetracycline, anticancer drug doxorubicins, agricultural herbicide thaxtomin A, and plant growth regulator guvermectin, all with the yields of >10 mg/g glucose in a simple mineral medium. Given that the production of SMs all required complexed medium and the cognate yields were usually much lower, our achievement of using a universal super-chassis and engineering pipeline in a simple mineral medium is promising for convenient heterologous production of SMs.

Preparation and characterization of EI-Co/Zr@AC and the mechanisms underlying its removal for atrazine in aqueous solution.

Atrazine, a widely used herbicide in agriculture, is detrimental to both the ecological environment and human health owing to its extensive use, poor degradability, and biotoxicity. The technology commonly used to remove atrazine from water is activated carbon adsorption, but it has the problems of difficult recovery, secondary contamination, and a low removal rate. To efficiently remove atrazine from agricultural wastewater, in this study, a new environmental material, embedding immobilization (EI)-Co- and Zr-modified activated carbon powder (Co/Zr@AC), was prepared by immobilizing the bimetallic Co/Zr@AC via EI technique and employed to remove atrazine. When preparing EI-Co/Zr@AC, the single-factor experiment was conducted and determined the optimal preparation conditions: sodium alginate 2.5% (wt), calcium chloride 4.0% (wt), Co/Zr@AC 1.0% (wt), and bentonite 2.0% (wt). The prepared EI-Co/Zr@AC has a three-dimensional mesh structure and many pores and also possesses good mass transfer performance and mechanical properties. The removal efficiency by EI-Co/Zr@AC for the removal of 5.0 mg/L atrazine from 50 mL was 94.1% at pH 7.0 and 25°C, with an EI-Co/Zr@AC dosage of 0.8 g. The mechanistic study showed that the pseudo-second-order kinetic model could describe the removal process better than the pseudo-first-order kinetic model, and the Freundlich isotherm model fit better than other isotherm models. Additionally, the synthesized EI-Co/Zr@AC spheres demonstrated good reusability, with the atrazine removal rate remaining 70.4% after five cycles, and the mechanical properties of the spheres were stable.

Unraveling the chemical fingerprint of the Miami River sources: Insights from high-resolution mass spectrometry and nontarget analysis

This study investigated the chemical composition of waters in the heavily urbanized and historically polluted Miami River, Florida. The goal was to assess the different water sources and anthropogenic influence in this managed area using nontarget analysis (NTA) combined with high-resolution mass spectrometry (HRMS). Surface water samples were collected from 10 sites during five sampling events in the wet season of 2021 and 2022. The HRMS data was processed using Compound Discoverer™ version 3.3, and the results were analyzed using techniques including Principal Component Analysis and Kendrick Mass Defect plots. Results showed a gradient change in the chemical composition from the Everglades to Biscayne Bay endmembers. The Seybold Canal, an adjacent canal, was consistently identified as a unique source of contaminants, contributing its own specific set of tracers. Increased presence and intensity of organic contaminants along the waterway was observed, indicating significant anthropogenic influence in the area. The NTA and post-processing were evaluated for reproducibility, demonstrating robustness with a 71.2% average reproducibility for compounds detected in 3 out of 5 sampling trips. A detection frequency of 80% (4 out of 5) was the set criterion for detected compounds suggested as tracers. To prioritize samples, hierarchical cluster analysis was employed, and potential tracers for each water source were determined. Tracers included natural products and agricultural herbicides and insecticides for the Everglades, anthropogenic contaminants for the Seybold Canal, and a lack of unique tracers for Biscayne Bay. Additionally, urban-influenced contaminants such as flame retardants, insect repellents, pharmaceuticals, and non-agricultural herbicides were identified along the river. This study highlights the impact of human activities on the Miami River and demonstrates the effectiveness of NTA in differentiating and tracking water sources. The results emphasize the importance of reproducibility in NTA and provide guidance on implementing monitoring strategies by prioritizing samples based on chemical compositions.

Achromobacter sp. Strain BUKˍBCHˍTQ1: A Potential Paraquat-Degrading Bacterium Isolated from Pesticide Contaminated Agricultural Soil

Paraquat (1, 1′-dimethyl-4, 4′-bipyridinium dichloride) is one of the most frequently used herbicide in agriculture. It is a cationic non-systematic, non-selective contact compound that instantaneously interferes with the photosynthetic processes of plants. It has an immediate effect, once the compound comes into contact with the plants’ leaves, where the reaction occurs. However, the contamination of paraquat residue in soil can harm soil microbes, flora and fauna, farmer health and also soil ecology, which affects the soil fertility. The objective of this study was to isolate and characterize bacteria with the ability to break down and utilize paraquat as the primary carbon source. The isolation process involved the enrichment of mineral salt media (MSM) using serial dilution. The isolated bacterium underwent morphological, biochemical, and molecular identification following characterization. Results showed the isolate was identified as Achromobacter sp. with the accession number OQ372943 based on partial 16S rRNA gene sequence and phylogenetic analysis. The growth and degradation of paraquat by this isolate were optimum at a pH of 6.5, 276 mgL-1 of the substrate (paraquat), temperature of 35 °C, 200 µL of biomass size, and 48 h of incubation. The degradation efficiency of the isolate after 120 hours of incubation under optimal conditions was 91.01%. Hence, these results demonstrated a very high efficiency of paraquat degradation. Consequently, this isolate holds significant promise for paraquat degradation and could serve as a viable contender for remediating paraquat-contaminated environments.

Agroecological assessment of herbicides application on soybean crops in the central zone of Krasnodar Territory, Russia

Aim. Agroecological assessment of herbicides application on crops of soybean variety Arleta in the central zone of Krasnodar Territory.Materials and Methods. The experiments were carried out on the experimental field of the Federal Research Centre of Biological Plant Protection in 2022 according to the methodological recommendations for testing herbicides in agriculture. Herbicides from different chemical classes were used in the experiment. Efficiency was assessed by the difference in weed and soybean grain yield in comparison with the control. The comparative ecotoxicological load of preparations was carried out according to the ecological load and the coefficient of selectivity of action for the soil.Results. Weed species in the experiment were highly effectively suppressed by the herbicides Pulsar, BP, Pivot, VK and a mixture of Bazagran, BP + Zellek Super, and KE (88–98 %). When using Dual Gold, EC, Frontier Optima, EC and Proponit, and EC before the soybean shoots, the biological efficacy was lower. The preparations Pulsar, BP and Pivot, and VK, in comparison with other herbicides, had a lower level of environmental load and a high coefficient of selective action and meet modern safety requirements for the natural environment.Conclusions. In order to protect the environment when choosing herbicides for application on soybean crops in the central zone of Krasnodar Territory, they should be comprehensively selected taking into account the ecotoxicological load of the preparations.

Выращивание березы на вырубках с применением гербицидов

Birch, being one of the main forest-forming tree species, has valuable and soughtafter timber. In production forest conditions, natural regeneration and crops of this species experience strong competition from both grass cover and undesirable hardwoods (aspen, gray alder and willow). Without carrying out high-quality maintenance (agrotechnical care, clearing), the formation of economically valuable birch forests is impossible. The most effective and economical is the chemical care method, which involves the use of modern environmentally friendly herbicides. However, if technological regulations and practical recommendations for the use of herbicides have already been developed for the care of coniferous species (pine, spruce and others), then there are currently no such recommendations for birch. The aim of the research is to develop a scientifically based method of caring for natural young birch stands (clearing, agrotechnical care) using selective herbicides on forest fund lands. The objects of research are seed and vegetative regeneration of birch in young stands formed in clear-cut areas, as well as undesirable herbaceous and tree-shrub vegetation. When laying the experiments and evaluating their results, we were guided by the generally accepted methodology for testing herbicides in agriculture. In field production and small-scale experiments with herbicides magnum, magnum super, mortira and anchor-85 in young stands with birch trees, the biological effectiveness of the action of the preparations on a wide range of undesirable vegetation was determined, as well as their selectivity with respect to birch. High efficiency of herbicides magnum (100–300 g/ha) and magnum super (100–200 g/ha) on dicotyledonous species of herbaceous vegetation and deciduous species – willow, aspen, gray alder and mountain-ash, as well as high resistance of birch to them at continuous spraying during the growing season was established. Herbicides mortira (100–200 g/ha) and anchor-85 (100 g/ha) were recognized as unsuitable for birch care. It was found that after a single application of herbicide magnum at rates of 100 and 200 g/ha in mixed young stands dominated by aspen, willow and gray alder and with participation of birch 1–2 composition units, stands dominated by the latter are formed. For citation: Egorov A.B., Postnikov A.M., Bubnov A.A., Pavluchenkova L.N., Partolina A.N. Growing Birch in Clear-cut Areas with Herbicide Application. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 58–74. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-58-74

MicroRNA-217-5p triggers dopaminergic neuronal degeneration via autophagy activation under Atrazine exposure

Atrazine (ATR) is a widely used agricultural herbicide, and its accumulation in soil and water can cause various environmental health problems. ATR has neurotoxic effects on dopaminergic neurons, which can lead to a Parkinson's disease (PD)-like syndrome. Epigenetics regulates gene expression dynamically through DNA methylation, histone post-translational modification, microRNA (miRNA) interaction, and RNA methylation. MicroRNA (miRNA), representing one of the primary epigenetic mechanisms responsible for regulating gene expression, plays a crucial role in maintaining normal cellular function, while dysregulation of miRNA expression has been observed in PD. This study aims to investigate the regulatory mechanisms of miRNA in ATR exposure. The results show that ATR-exposure significantly upregulates the expression level of miR-217-5p. Both miR-217-5p overexpression and ATR exposure is able to trigger the autophagy process and apoptosis. Conversely, inhibiting the expression of miR-217-5p can reverse the levels of ATR-induced autophagy and apoptosis. Moreover, ATR causes damage to dopaminergic neurons, as indicated by the altered expression of tyrosine hydroxylase and α-synuclein. Taken together, these results suggest that ATR-induced autophagy can accelerate the progression of neurodegenerative diseases and that miR-217-5p is probably an important target involved in ATR-induced dopaminergic damage, shedding important light on the development of a novel strategy for treating neurodegenerative diseases.

New Advances in Nano-Enabled Weed Management Using Poly(Epsilon-Caprolactone)-Based Nanoherbicides: A Review

The number of effective herbicides available to farmers is steadily decreasing due to increasing herbicide resistance. It seems very important to address and effectively deal with the main weed management challenges (low crop yield and environmental pollution) by investigating the potential of newly introduced materials, such as biocompatible polymer-based nanoparticles. The current review aims to encourage agricultural or environmental researchers to conduct new research on the synthesis and application of modified herbicides, such as nanoherbicides, for application in weed management and to provide a comprehensive foundation on the topic. Such nanosystems could help with the promotion of the controlled release of active ingredients and extend their action time, resulting in a reduction in dose and application number; improve the physical and chemical characteristics of the herbicide to increase foliar adhesion; prevent degradation that results from environmental factors (such as sunlight, temperature, microorganisms, or pH); and decrease herbicide leaching and contamination of the environment. Furthermore, it has been indicated that some polymeric nanocarriers can penetrate biological barriers, including membranes and plant cell walls, and translocate across vascular tissues, resulting in a more efficient delivery of active ingredients. Poly(epsilon-caprolactone) is a biocompatible material that is easily decomposable by enzymes and fungi. PCL nanoparticles could be applied as nanocarriers of herbicides in agriculture due to their low toxicity, their potential for large-scale synthesis from inexpensive materials, their ability to dissolve herbicides, their high loading capacity, and their ability to help minimize the chemical decomposition of herbicides.

Acute toxicity and genotoxicity of the S-metolachlor-based herbicide Dual Gold® on Leptodactylus luctator (Hudson, 1892) tadpoles (Anura: Leptodactylidae).

Herbicides used in agriculture and their metabolites are frequently detected in surface water bodies, where they can persist and cause adverse effects on aquatic organisms. The aim of this study was to evaluate the acute toxicity and genotoxic effects of the S-metolachlor (SM)-based herbicide Dual Gold® (DG®), on Leptodactylus luctator tadpoles (Anura: Leptodactylidae). To assess the toxicity of the herbicide, including the median lethal concentration (LC50) at 24h, the no-observed-effect concentration (NOEC), and the lowest-observed-effect concentration (LOEC), tadpoles were exposed to five nominal concentrations of DG® (5.0, 6.2, 7.8, 9.8, and 12.2 mg/L), and to dechlorinated water as a negative control (NC). The LC5024h of DG® was 7.0 mg/L, the NOEC was 5.0 mg/L and the LOEC=6.2 mg/L. L. luctator tadpoles were sensitive to the herbicide, reaching 100% mortality after 24 h of exposure to the highest concentration tested (12.2 mg/L). To evaluate the potential genotoxicity of the herbicide, the frequencies of micronuclei (MN) and other erythrocyte nuclear abnormalities (ENA) were determined in larvae exposed to three nominal concentrations of DG® (1.0, 5.0, and 6.2 mg/L) for 48 and 96 h. The frequencies of MN and ENA were compared with a positive control (40 mg/L of Cyclophosphamide) and a negative control. The frequencies of MN and ENA in the erythrocytes of tadpoles exposed to the test concentrations of DG® and Cyclophosphamide were significantly higher than in the negative control group at both 48 and 96 h (with the only exception of MN at 1.0 mg/L at 48 h). Our results confirm the genotoxic and cytotoxic effects of this widely used herbicide in agriculture, a fact that represents a potential risk to amphibians that develop in ponds associated with or immersed in agroecosystems.

Adverse developmental impacts in progeny of zebrafish exposed to the agricultural herbicide atrazine during embryogenesis

Atrazine (ATZ) is an herbicide commonly used on crops in the Midwestern US and other select global regions. The US Environmental Protection Agency ATZ regulatory limit is 3 parts per billion (ppb; µg/L), but this limit is often exceeded. ATZ has a long half-life, is a common contaminant of drinking water sources, and is indicated as an endocrine disrupting chemical in multiple species. The zebrafish was used to test the hypothesis that an embryonic parental ATZ exposure alters protein levels leading to modifications in morphology and behavior in developing progeny. Zebrafish embryos (F1) were collected from adults (F0) exposed to 0, 0.3, 3, or 30 ppb ATZ during embryogenesis. Differential proteomics, morphology, and behavior assays were completed with offspring aged 120 or 144 h with no additional chemical treatment. Proteomic analysis identified differential expression of proteins associated with neurological development and disease; and organ and organismal morphology, development, and injury, specifically the skeletomuscular system. Head length and ratio of head length to total length was significantly increased in the F1 of 0.3 and 30 ppb ATZ groups (p < 0.05). Based on molecular pathway alterations, further craniofacial morphology assessment found decreased distance for cartilaginous structures, decreased surface area and distance between saccular otoliths, and a more posteriorly positioned notochord (p < 0.05), indicating delayed ossification and skeletal growth. The visual motor response assay showed hyperactivity in progeny of the 30 ppb treatment group for distance moved and of the 0.3 and 30 ppb treatment groups for time spent moving (p < 0.05). Due to the changes in saccular otoliths, an acoustic startle assay was completed and showed decreased response in the 0.3 and 30 ppb treatments (p < 0.05). These findings suggest that a single embryonic parental exposure alters cellular pathways in their progeny that lead to perturbations in craniofacial development and behavior.

Sub-acute toxicity of the herbicide glufosinate-ammonium exposure in adult red swamp crayfish (Procambarus clarkii)

Glufosinateammonium (GLA) is one of the most widely used agricultural herbicides. It is frequently detected in surface waters near farmland and may pose a risk to non-target aquatic species. This study aimed to explore the toxicity of subacute GLA exposure in crayfish. Adult red swamp crayfish were exposed to GLA (0, 1, 10, and 100 mg/L) for 21 days. Bioaccumulation, oxidative stress, nonspecific immunity, and the expression of genes encoding xenobiotic detoxification-related enzymes were examined. The results showed GLA accumulation and hepatopancreatic histopathological changes (dilation of hepatic tubules and vacuolation of hepatocytes) in the exposed crayfish. GLA exposure induced ROS production, inhibited glutathione expression, and catalase activity in the crayfish hepatopancreas, as well as inhibited immunoenzyme expression (acid phosphatase, alkaline phosphatase, and lysozyme) in the hemolymph. In addition, the total hemocyte number decreased, and the proportion of hemocyte subsets changed significantly. Superoxide dismutase first increased and then decreased with increasing GLA dosage. GLA promoted the expression of biotransformation enzymes (cypb5, gst) in the hepatopancreas. Our results suggest that subacute GLA exposure caused structural damage to the hepatopancreatic tissue and decreased antioxidant capacity and non-specific immunity in crayfish. These findings provide insight into the toxicity of herbicides on non-target organisms.

Removal of an agricultural herbicide (2,4-Dichlorophenoxyacetic acid) using magnetic nanocomposite: A combined experimental and modeling studies

This study focused on modeling the removal of one of the widely used agricultural herbicides known as 2,4-Dichlorophenoxyacetic acid (2,4-D) using polypyrrole-coated Fe2O3 nanoparticles (Fe2O3@PPy). The Fe2O3@PPy nanocomposite was synthesized by surface-coating the Tabebuia aurea leaf extract synthesized Fe2O3 nanoparticles with polypyrrole. After characterization, the adsorptive potential of the nanocomposite for removing 2,4-D from aqueous solution was examined. Central composite design (CCD) was employed for optimizing the adsorption, revealing an adsorption efficiency of 90.65% at a 2,4-D concentration of 12 ppm, a dosage of 3.8 g/L, an agitation speed of 150 rpm, and 196 min. Adsorption dataset fitted satisfactorily to Langmuir isotherm (R2: 0.984 & χ2: 0.054) and pseudo-second-order kinetics (R2: 0.929 & χ2: 0.013) whereas the exothermic and spontaneous nature were confirmed via the thermodynamic study. The predictive models, including adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN), and response surface methodology (RSM), demonstrated good precision for the prediction of 2,4-D adsorption, with respective R2 of 0.9719, 0.9604, and 0.9528. Nevertheless, statistical analysis supported ANFIS as the better forecasting tool, while RSM was the least effective. The maximum adsorption capacity of 2,4-D onto the Fe2O3@PPy nanocomposite was 7.29 mg/g, significantly higher than a few reported values. Therefore, the Fe2O3@PPy nanocomposite could serve as a competent adsorbent to remove 2,4-D herbicide from aqueous streams.

Effect of cation hydrophobicity in dicamba-based ionic liquids on herbicide accumulation and bioavailability in soil

One of the main environmental problems due to using herbicides in agriculture is their mobility and leachability from crop fields. Using an ‘ionic liquid’ strategy, we set out to see if it was possible to increase the hydrophobicity of the soluble, easily leached anionic herbicide, dicamba, by combining it with a cation exhibiting increased hydrophobicity, through the incorporation of a C8, C10, C12 and C14 alkyl chain into the structure of naturally derived choline. Hydrophobic modifications of the choline cation were quantitatively sorbed in agricultural soil, posing a long-term danger of accumulation. In addition, the possibility of negative effects on microorganisms, as well as plant germination and development were noted for all tested ionic liquids. Nevertheless, the parameters Kd (0.7–0.8 [L/kg]), Koc (54–58 [L/kg]) and GUS (4.5–3.5) and LIX (0.34) determined for dicamba clearly indicated that this herbicide functions in the soil independently of the cation with which it was originally paired in the ionic liquid. These observations are consistent with the absence of intermolecular interactions between ionic protons, confirmed by the 1H–1H NOESY spectra. The multi-level analysis of ionic liquids, containing herbicidal anion, and the subsequent interactions showed that they are not a new and distinct group of emerging contaminants, but a mixture of known cations and anions that function independently of each other in the environment.

How Benthic Sediment Microbial Communities Respond to Glyphosate and Its Metabolite: a Microcosm Experiment.

Glyphosate is the most commonly used agricultural herbicide in the world. In aquatic ecosystems, glyphosate often adsorbs to benthic substrates or is metabolized and degraded by microorganisms. The effects of glyphosate on microbial communities vary widely as microorganisms respond differently to exposure. To help understand the impacts of glyphosate on the sediment microbiome, we conducted a microcosm experiment examining the responses of benthic sediment microbial communities to herbicide treatments. Sediments from a prairie pothole wetland were collected, and 16S rRNA gene sequencing was used to analyze community composition 2-h and 14-days after a single treatment of low (0.07 ppm), medium (0.7 ppm), or high (7 ppm) glyphosate, aminomethylphosphonic acid (glyphosate metabolite), or a glyphosate-based commercial formula. We found no significant differences in microbial community composition across treatments, concentration levels, or day of sampling. These findings suggest that microbial species in the Prairie Pothole Region of North America may be tolerant to glyphosate exposure.

A Review of the Current Panorama of Glyphosate Resistance among Weeds in Mexico and the Rest of the World

Glyphosate is a non-selective broad-spectrum herbicide. Although the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC) have classified it as probably carcinogenic to humans, the indiscriminate use of this herbicide in agriculture continues today, as a consequence of its low cost and effectiveness, as well as of the large number of generic products available. In addition to the adverse health effects, the massive use of glyphosate has caused environmental problems which have direct and indirect effects on agroecosystems. With the introduction of resistant transgenic crops, the use of this herbicide has increased fifteenfold since 1996. Just in the last 26 years, 350 cases of glyphosate resistance among weeds have been reported worldwide; however, multiple resistance has been recorded in 23 weed species in 17 countries around the world. In the future, the dependence on this herbicide will result in multiple resistance among weeds, not only in Mexico, but in more parts of the world than those that have been reported to date.