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Herein, nitrogen is doped into carbon quantum dots (N‐CQDs) using a hydrothermal method for the rapid detection of metolachlor in grain. The morphological features, elemental compositions, and optical properties of the N‐CQDs are then analyzed and investigated using transmission electron microscopy, X‐ray photoelectron spectroscopy, and fluorescence spectroscopy, respectively. Based on the principle of intramolecular charge transfer, a fluorescent probe is constructed for the rapid detection of metolachlor. Under optimal experimental conditions, the fluorescence intensity change values of the N‐CQDs and metolachlor concentration have a good linear relationship when the concentration of metolachlor is in the range of 0.0125−2.5 μg mL−1. An evaluation of the method shows that the method has good selectivity, reproducibility, and stability, with a limit of detection of 1.63 μg kg−1 and a limit of quantification of 3.92 μg kg−1. The spiked recoveries of six real samples are tested using a spiked recovery assay that yielded spiked recoveries in the range of 105.05−87.13%, and their relative standard deviations (n = 3) ranged from 4.62% to 0.61%, indicating that the method can be used for detection in actual samples with good precision and stability. [ABSTRACT FROM AUTHOR]

The article discusses research which examined the effect of various weed management practices on weed indices in sweet corn. The field experiment records the effect of pre-emergence application of metolachlor herbicide plus intercropping on total weed count, the effect of metolachlor plus intercropping on weed biomass and weed seeds germination, and effect of metolachlor plus intercropping on weed control index.

Pre-emergence (PE) atrazine is the most commonly used herbicide in forage sorghum, however, the discovery of new generation herbicides has opened weed control windows to be explored in forage sorghum for an extended period of weed control. Hence, a field experiment was conducted during rainy (kharif) seasons of 2021 and 2022 at Punjab Agricultural University, Ludhiana, India to evaluate the phytotoxicity and efficacy of very-long chain fatty acid elongase (VLCFAE)-inhibiting pre-emergence (PE) herbicides (metolachlor and pyroxasulfone) in comparison with PE atrazine alone and in sequence with post-emergence (PoE) atrazine and 2, 4-D. Weed free and weedy check treatments were also kept for comparison. No phytotoxicity of metolachlor on sorghum was observed, while pyroxasulfone’s phytotoxicity was minimal (rating < 3) but weed control was efficient and crop recovered vigorously in later stages. Using the pooled data from the two years, significantly lower (P ≤ 0.05) weed population by 98% was recorded in both PE pyroxasulfone and metolachlor over weedy check at harvest besides significant reduction in dry matter of weeds. The average WCE was highest in PE pyroxasulfone and increased progressively from 71.6% at 20 days after PE application to 92.2% at harvest. Treatment PE pyroxasulfone recorded significantly (P ≤ 0.05) higher green fodder yield over the other treatments (except weed free) although the differences were non-significant. The high cost of pyroxasulfone perhaps led to its BC ratio lower than the remaining treatments while PE atrazine alone and in sequence with post-emergence (PoE) atrazine recorded higher BC ratio. Nevertheless, pyroxasulfone could be an option for controlling the diversified and difficult to control weed flora in sorghum fodder as the study shows that the uncontrolled weeds (weedy check) on an average have caused 50.9, 48.3 and 59.8% reduction in green fodder yield, dry matter yield and net returns, respectively when compared to weed free check. [ABSTRACT FROM AUTHOR]

Sorption is the most important process influencing the amount of herbicide retained in soils. The special properties of biochar could influence the soil retention of pollutants through adsorption. However, the detailed sorption mechanisms as influenced before and after applying biochar to soils with different properties are unclear. This study examined the sorption characteristics of metolachlor using soil samples collected from South China. Sorption experiments were conducted using a batch equilibration method. After comparing the metolachlor sorption constants observed for all soil samples, our results showed that the application of biochar significantly increased the capacity of metolachlor adsorption. Without biochar, sorption capacity (Kf) was positively related to soil organic matter and to a soil particle size of 0.002–0.02 mm in soils developed from granite, of 0.002–0.02 mm in soils developed from delta shockwaves, and of 0.002–0.02 mm, together with complex iron oxide and total iron content, in soils developed from arenaceous shale. Moreover, sorption capacity (Kf) with biochar was positively related to peroxidase in soils developed from granite and to dissociative iron oxide and total iron content in soils developed from arenaceous shale. Our results show that biochar greatly affects metolachlor sorption behavior, probably because of qualitative differences in the structural characteristics of soils with different developmental parent materials and properties. [ABSTRACT FROM AUTHOR]

Antipredator behaviors are often crucial for animal survival. In environments impacted by humans, animals may be exposed to a wide array of chemical contaminants due to agriculture, industry, and other activities. Among other effects, these chemical contaminants may influence behaviors prey animals use to cope with predation risk, likely reducing survival by suppressing or even maladaptively reversing normal behavioral responses. Changes in behavioral responses could be the result of impaired detection of cues that indicate predator presence or altered behavioral plasticity in response to predator cues. In a laboratory experiment, we tested the effects of the commonly used herbicide metolachlor on the behavior of tadpoles of the American bullfrog (Lithobates catesbeianus) in both the absence and presence of water conditioned with cues (odor) of fish. We observed several behaviors in the tadpoles reflective of predator avoidance when exposed to combinations of metolachlor (0 or 80 ppb) and the presence or absence of fish cues. We found that metolachlor had size-dependent effects on tadpole activity levels, with larger tadpoles being much less active in the absence of metolachlor but similar in activity to small tadpoles when metolachlor was present. Fish cues similarly had size-dependent effects on multiple tadpole behaviors. Finally, hiding behavior and zone change (movement) behavior of tadpoles in response to fish cues varied depending on the presence of metolachlor and, in the case of zone changes, tadpole size. Our findings indicate that the presence of chemical contaminants has the potential to alter important antipredator behaviors. However, these effects are complex, and size may mediate the nature of the response to both chemical contaminants and predators. The herbicide metolachlor alters tadpole behavior, sometimes interactively with fish cues. Body size of tadpoles influenced the effects of metolachlor and fish. [ABSTRACT FROM AUTHOR]

The study illustrates the use of polyelectrolyte multilayer (PEM) membranes prepared with weak/strong polyelectrolyte combination of poly(ethyleneimine)/chondroitin sulfate A (PEI/CS) for the removal of metolachlor (MTR) from water samples. The proposed PEM membranes were characterized by chemical, physical, thermal, and morphological properties. The removal of MTR herbicide by PEI/CS multilayer deposited on a microfiltration polyamide membrane was found to be efficient with a retention rate of about 96.46% for 8 bilayers sat an excellent permeate flux of 6.27 m3/m2 day. The photodegradation of metolachlor which got trapped in PEMs in the presence of riboflavin (Rb) sensitizer was investigated at various concentrations. A comparative study on photo-elimination of MTR without the presence of Rb was also done. The degradation time was greatly shortened from more than 1 h for direct photolysis to 5–15 min depending on the initial concentration of the sensitizer. The degradation of metolachlor in the presence of Rb as well as direct photolysis was also experimentally studied. [ABSTRACT FROM AUTHOR]

Pesticides and climate change are both thought to contribute to the global amphibian decline, yet their combined effects are still poorly understood. Metolachlor is a widespread herbicide applied across North America, but little is known about its effects on amphibians. We used a replicated mesocosm experimental design with different levels of drying (i.e., no drying and medium and rapid drying) and metolachlor concentrations (0, 0.8, 8, and 80 µg/L) to assess their respective and combined effects on wood frog (Lithobates sylvaticus) larvae throughout metamorphosis. Metolachlor had no significant effect on survival and development of tadpoles. However, metolachlor significantly interacted with drying levels to reduce the growth of tadpoles, which was mainly due to a difference detected among metolachlor concentrations under the rapid drying treatment. Drying also directly reduced growth and body mass at metamorphosis. Our results suggest that environmental stressors, such as drying, should be considered in toxicological experiments to provide relevant exposure conditions to pesticides for ephemeral pond species in the context of global climate change. Environ Toxicol Chem 2023;42:1772–1781. © 2023 SETAC [ABSTRACT FROM AUTHOR]

The majority of studies concerning the environmental behavior of hydrophobic pollutants in soil consider soil organic matter (SOM) content as a main factor influencing chemical retention, whereas the composition of SOM and its individual fraction share are often neglected. In the present paper, carbaryl, carbofuran and metolachlor retention by loamy sand and loam topsoil materials is compared and referred to humic acids (CHA) and the residual carbon (CR) content of SOM. Additionally, the sorption-desorption behavior of agrochemicals in soils was tested at a pH of three to seven. Calculated isothermal parameters point to favorable, spontaneous and physical pesticide sorption. Groundwater ubiquity score (GUS) indexes confirmed the low leaching ability of metolachlor on soils and moderate of carbofuran. The high affinity of carbaryl to CR may explain its pronounced sorption in loam soil and the lowest percolation potential. Carbofuran retention in soils was associated with montmorillonite (Mt) and CR fractions. Meanwhile, metolachlor uptake was related to humic acid and Mt content of the soils. Lower pH enhanced retention of the agrochemicals, except for carbaryl sorption in sandy loam soil. Results of this study highlight that SOM composition and mutual share of individual organic carbon fractions alongside pH may play a crucial role in predicting non-ionic pesticide behavior in soil. [ABSTRACT FROM AUTHOR]

We developed, tested, and optimized two laboratory denitrification assays for both managers and scientists to assess the effects of xenobiotics on the denitrification process over 7 days (short batch assay, SBA) and 28 days (long semi-continuous assay, LSA). The assays facilitate (1) measuring the efficiency of nitrate removal under the influence of xenobiotics, (2) determining the removal of the tested xenobiotics via adsorption or biotic decomposition, and (3) testing the influencing parameters for optimizing the denitrification process. The adsorption of the xenobiotics was assessed by inhibiting all biological processes through the addition of HgCl2. Our tests demonstrate that the ratio of the initial nitrate concentration to the amount of bioavailable organic matter provided is essential to avoid organic carbon or nitrate limitation. While a pH < 7 resulted in decreased denitrification, a pH > 8 led to nitrite accumulation, indicating incomplete denitrification. Over durations of more than a week, weekly replenishments of the nitrate and HgCl2 and weekly purging with argon gas to reduce the oxygen concentrations are needed. The assays provide information about the accumulation of xenobiotics in the bioreactors that is necessary for the environmentally friendly treatment of the bioreactor fillings and provide insight into the potential of the bioreactors to remove pesticides from polluted water resources. [ABSTRACT FROM AUTHOR]

This study analyses the floristic composition of field weeds recorded at the University of Ilorin Teaching and Research Farm (008° 27' 23.9'N and 004° 39' 42.9'E) in the southern Guinea savannah of Nigeria during the 2019 - 2021 growing seasons. The area is characterized by a bimodal rainfall pattern with an average annual rainfall of 1227.85 mm and sandy loam soil (plinthustaffs). The experiment was set up as a randomized complete block design and repeated three times in a field that had been continuously maize-cropped for 10 years. Treatments were preemergence applications of atrazine, metolachlor, and primextra at the rate of 1.5, 2.5, and 3.5 kg a.i.ha-1 and Weedy Check. Maize was sown and maintained using the recommended agronomic practices for ecology. Weed species composition was estimated using four continuous sample quadrats (0.5 m²) at 3, 6, 9, and 12 weeks after sowing. The weed flora consisted of 48% broadleaves, grasses 45%, and 7% sedges. Between 2019 and 2021 there was a gradual shift from the predominant annual broadleaves to induced annual grasses and a reduction in the floristic composition of the weed community by approximately 2 - 28%. Fifteen (15) weed species were predominant and the most stable weed species were Richardia scabra, Digitaria horizontalis and Digitaria sanguinalis. This requires finding an ideal weed control option that controls the negative impact of agricultural weeds on crop after yield while maintaining a diverse weed community. [ABSTRACT FROM AUTHOR]

The presence of weeds in the sunflower crop is one of the main factors linked to the low increase in productivity of this crop, and to determine the most appropriate management of weeds, it is essential to carry out a diagnosis through the phytosociological survey. The objective of this study was to assess the influence of chemical control on the phytosociological community of weeds in three areas cultivated with sunflower in the Parecis region (Brazil). The areas were treated with 2,4-D + glyphosate for desiccation; S-metolachlor was used for pre-emergence control in the three areas; meanwhile, sulfentrazone and flumioxazin were applied only in one area; and, finally, clethodim was applied for post-emergence weed management. Sampling was carried out at two different times, in the initial and pre-harvest stages (at 35 and 100 days after the emergence of the crop, respectively), using a quadrate, in which weeds were identified and quantified to determine the frequency, relative frequency, density, relative density, abundance, relative abundance, importance index, and similarity index between areas and times. Seventeen weed species were found in the sunflower crop (70.6% dicot and 29.4% monocotyledonous) in the two seasons, grouped into nine botanical families, with Poaceae being the most diverse family. The dicots Tridax procumbens and Acanthospermum hispidium were present in low frequency only in the initial stages of development of the sunflower crop. The weeds with the highest importance index values in the initial and pre-harvest stages were Euphorbia hirta (104 and 91%) and Bidens pilosa (45 and 66%, respectively), both belonging to the dicots group. These two species were present in the two evaluated periods and in the three experimental areas, demonstrating that there was a similarity index between them with values above 93%. These results of the phytosociological study may contribute to determining more efficient management strategies for weed chemical control in the sunflower crop. [ABSTRACT FROM AUTHOR]

Cowpea (Vigna unguiculata L. Walp.) production in Nigeria is limited mainly due to weed and insect infestations. The effects of insecticide spray regime and weed control on the productivity of cowpea were evaluated in the early and late seasons of 2020. Two insecticide sprays produced increased growth and yield in the late cropping season. However, in the early cropping season, optimum growth and yield of cowpea were obtained with four insecticide sprays. Regardless of the cropping season, preemergence (PRE) application of metolachlor or propaben plus manual weeding (MW) provided 71–80% reduction in weed density and biomass and resulted in cowpea growth and yields similar to the weed-free control. In the late season, two MWs resulted in cowpea growth and yield similar to the weed-free control. However, in the early season treatment, two MWs resulted in 51% lower yield than the weed-free control. The results showed that four insecticide sprays in the early cropping season or two insecticidal sprays in the late cropping season integrated with metolachlor or propaben application plus MW improved the productivity of cowpea. [ABSTRACT FROM AUTHOR]

Glyphosate, the most heavily used herbicide world‐wide, is applied to plants in complex formulations that promote absorption. The National Toxicology Program reported in 1992 that glyphosate, administered to rats and mice at doses up to 50,000 ppm in feed for 13 weeks, showed little evidence of toxicity, and no induction of micronuclei was observed in the mice in this study. Subsequently, mechanistic studies of glyphosate and glyphosate‐based formulations (GBFs) that have focused on DNA damage and oxidative stress suggest that glyphosate may have genotoxic potential. However, few of these studies directly compared glyphosate to GBFs, or effects among GBFs. To address these data gaps, we tested glyphosate, glyphosate isopropylamine (IPA), and (aminomethyl)phosphonic acid (AMPA, a microbial metabolite of glyphosate), 9 high‐use agricultural GBFs, 4 residential‐use GBFs, and additional herbicides (metolachlor, mesotrione, and diquat dibromide) present in some of the GBFs in bacterial mutagenicity tests, and in human TK6 cells using a micronucleus assay and a multiplexed DNA damage assay. Our results showed no genotoxicity or notable cytotoxicity for glyphosate or AMPA at concentrations up to 10 mM, while all GBFs and herbicides other than glyphosate were cytotoxic, and some showed genotoxic activity. An in vitro to in vivo extrapolation of results for glyphosate suggests that it is of low toxicological concern for humans. In conclusion, these results demonstrate a lack of genotoxicity for glyphosate, consistent with observations in the NTP in vivo study, and suggest that toxicity associated with GBFs may be related to other components of these formulations. [ABSTRACT FROM AUTHOR]

Biochar activation methods have attracted extensive attention due to their great role in improving sorptive properties of carbon-based materials. As a result, chemically modified biochars gained application potential in the purification of soil and water from xenobiotics. This paper describes changes in selected physicochemical properties of high-temperature wheat-straw biochar (BC) upon its deashing. On the pristine and chemically activated biochar (BCd) retention of five pesticides of endocrine disrupting activity (carbaryl, carbofuran, 2,4-D, MCPA and metolachlor) was studied. Deashing resulted in increased sorbent aromaticity and abundance in surface hydroxyl groups. BCd exhibited more developed meso- and microporosity and nearly triple the surface area of BC. Hydrophobic pesticides (metolachlor and carbamates) displayed comparably high (88–98%) and irreversible adsorption on both BCs, due to the pore filling, whereas the hydrophilic and ionic phenoxyacetic acids were weakly and reversibly sorbed on BC (7.3 and 39% of 2,4-D and MCPA dose introduced). Their removal from solution and hence retention on the deashed biochar was nearly total, due to the increased sorbent surface area and interactions of the agrochemicals with unclogged OH groups. The modified biochar has the potential to serve as a superabsorbent, immobilizing organic pollutant of diverse hydrophobicity from water and soil solution. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An efficient synthesis of a well known chiral herbicide, (S)-metolachlor has been described using 2-methoxymethylaziridine ring formation and reductive ring opening as key steps using commercially available (R)-epichlorohydrin. The present protocol delivers the required enantiomer of metolachlor in overall yield of 50.8% and high enantiopurity (>99%). [ABSTRACT FROM AUTHOR]

The main objective of this research is to test functionalized siliceous materials as adsorbents to reduce the concentration of herbicides metolachlor and pendimethalin in aqueous solutions, and therefore contribute to the search of new materials for removal of herbicides from polluted water. Commercial silica was functionalized with mercaptopropyl and aminopropyl moieties. Aminopropyl silica was post-modified with phenoxyacetyl and benzoyl groups. Characterization of these functionalized materials has been done by means of nitrogen adsorption isotherms (in order to obtain textural properties), infrared spectroscopy and thermogravimetric analysis (to explore their chemical features). Adsorption kinetics and isotherms of metolachlor and pendimethalin were studied in batch experiments. Nitrogen adsorption isotherms show that functionalization reactions lower the total surface area of the solids. On the other hand, infrared spectra and thermogravimetric analysis confirm functionalization. Respecting adsorption kinetics, the process follows a pseudo-second order pattern in all cases. Adsorption isotherms can be described by Sips model, and they can be classified as S type in most of the cases. Silica functionalized with benzoylamidopropyl moieties exhibits the highest adsorption effectiveness towards both herbicides. It has 170% and 360% higher adsorption capacity than silica towards metolachlor and pendimethalin, respectively; while residual herbicide left in solution after adsorption practically reduces to a half when compared with silica. It can be concluded that chemical modification of the surfaces can be directed towards the discovery of new materials for water remediation. [ABSTRACT FROM AUTHOR]

BACKGROUND: The adverse effects of pesticides has led to a series of ecological, environmental and public health issues. Amide herbicides are an important agrochemical, yet many are prone to leach and pollute the environment, which limits their further application. In this study, metolachlor (METO) was selected as a model pesticide and a controlled released nanoparticle (NP) system was constructed employing a zeolitic imidazolate framework‐8 hybrid inorganic–organic porous material (METO@ZIF‐8). RESULTS: The synthesis parameters of METO@ZIF‐8 were optimized, and the loading content of METO@ZIF‐8 was maximized by a central composite design of response surface test. The NPs were regular dodecahedron with uniform size (mostly 54.3 nm diameter). METO@ZIF‐8 had high specific surface area and good dispersal in water. Moreover, it endowed the active ingredient with a pH‐responsive release property. The nanocarrier effectively improved the adsorption capacity of METO in soil and reduce the leaching by 10.3–21.7%. Pot experiments suggested that the control effect of METO@ZIF‐8 was 16.6 and 48.4% higher than that of METO emulsifiable concentrate (EC) and METO technical concentration (TC) at the recommended dose. Based on the excellent controlled release profiles, METO@ZIF‐8 did not affect corn plant growth and significantly reduced the risk of phytotoxicity induced by METO. METO@ZIF‐8 effectively reduced acute toxicity in zebrafish compared with METO EC. CONCLUSION: This study explored the fabrication of a nanocarrier for improving the efficacy and promoting the environmental safety of leachable amide herbicides. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

While there has been intensive research on the influence of microplastics (MPs) on aquatic organisms and humans, their effect on microorganisms is relatively little-known. The present study describes the response of the Trichoderma harzianum strain to low-density polyethylene (LDPE) microparticles. MPs, either separately or with metolachlor (MET), were added to the cultures. Initially, MP was not found to have a negative effect on fungal growth and MET degradation. After 72 h of cultivation, the content of fungal biomass in samples with MPs was almost three times higher than that in the cultures without MPs. Additionally, a 75% degradation of the initial MET was observed. However, due to the qualitative and quantitative changes in individual classes of phospholipids, cell membrane permeability was increased. Additionally, MPs induced the overproduction of reactive oxygen species. The activity of superoxide dismutase and catalase was also increased in response to MPs. Despite these defense mechanisms, there was enhanced lipid peroxidation in the cultures containing the LDPE microparticles. The results of the study may fill the knowledge gap on the influence of MPs on filamentous fungi. The findings will be helpful in future research on the biodegradation of contaminants coexisting with MPs in soil. [ABSTRACT FROM AUTHOR]

An appropriate herbicide type and concentration is essential for effective weed management and enhancing crop yield. However, the optimal herbicide type and corresponding application concentration for controlling weeds in common buckwheat on the Loess Plateau region of Northwestern China remain unclear. To address this gap, experiments were conducted to investigate the effects of various herbicides on weed control, dry matter accumulation, and grain yield in common buckwheat, and to analyze the variances in weed control efficacy and grain yields of the optimal herbicides at different concentrations. The results showed that both metolachlor and quizalofop-P-ethyl demonstrated effective weed control with lower phytotoxicity. Dry matter accumulation was lower under metolachlor, with no significant differences observed among the post-emergence herbicide treatments. Importantly, metolachlor and quizalofop-P-ethyl promoted the allocation of dry matter to grains. Remarkably, metolachlor and quizalofop-P-ethyl increased the grain yield by 15.59% and 26.97%, respectively, compared to spraying an equivalent amount of water. Additionally, the m2.25, q0.9, and q1.2 treatments exhibited excellent weed control effectiveness. And the higher grainnumber per plant observed under m2.25, q0.9, and q1.2 contributed to the increase in grain yield. Consequently, m2.25, q0.9 and q1.2 increased the grain yield by 34.42%, 38.86% and 33.16%, respectively. These findings demonstrate that applying metolachlor and quizalofop-P-ethyl at 2.25 L ha−1 and 0.9 or 1.2 L ha−1 respectively, is beneficial for efficient weed management and yield enhancement in common buckwheat cultivation on the Loess Plateau region of Northwestern China. These studies provide important guidance for promoting common buckwheat cultivation in this region. • Metolachlor and quizalofop-P-ethyl exhibited outstanding weed control with minimal toxicity. • Metolachlor and quizalofop-P-ethyl optimized grain yield. • Metolachlor (2.25 L ha−1) and quizalofop-P-ethyl (0.9 or 1.2 L ha−1) demonstrated excellent weed control. • Metolachlor (2.25 L ha−1) and quizalofop-P-ethyl (0.9 or 1.2 L ha−1) maximized grain yield. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antibiotics altered the biotransformation of metolachlor in soil-pea system. • The changed transformation posed higher potential risk to earthworm. • Antibiotics led ROS accumulation in pea, inhibiting CYP450 and detoxification of pea. Antibiotics are widely detected in farmland, which may influence the environmental behavior and risks of the coexisting pesticide. In this work, the effects of antibiotics on metolachlor transformation in soil-pea and the risk of metolachlor to earthworm were assessed, and the mechanism was explored in view of detoxifying process and oxidative stress. Antibiotics affected not the degradation rate but the metabolic profile of metolachlor. In soil, the content of metabolites oxaloacetic acid (OA) and ethane sulfonic acid (ESA) was decreased and dechlorometolachlor (DCL) was increased by antibiotics. In pea, the accumulation of metolachlor, DCL and ESA was decreased, while OA was increased by antibiotics. The changed transformation of metolachlor affected the risk to earthworm according to risk quote assessment. In further research, it was found that cytochrome P450 (CYP450) enzyme was reduced by 12.3% − 30.4% in soil and 12.4% − 23.6% in pea, which might due to excessive ROS accumulation induced by antibiotics, thus affecting the transformation and metabolite profile of metolachlor in soil–plant system. [ABSTRACT FROM AUTHOR]

Investigating the effects of microplastics remains a pertinent issue given the extensive biodiversity of exposed organisms, variations in the mechanisms of action among individual polymers, and their reliance on environmental conditions. Therefore, the objective of the study was to investigate some interactions of the popular biodegradable plastic poly(butylene adipate-co-terephthalate) (PBAT) on some aspects of the physiology of filamentous fungi Trichoderma spp., integral components of the soil microbiome known for promoting plant growth and aiding in pollution remediation. In the two Trichoderma strains examined, a positive influence on fungal growth was observed in the presence of microplastics (MPs). The capability to degrade MPs with the involvement of cytochrome P450 monooxygenases was confirmed through the detection of terephthalic acid (TPA) in postculture extractions. Additionally, inhibition of degradative activity in the presence of MPs was observed for metolachlor (MET) and 2,4-dichlorophenoxyacetic acid (2,4-D). Moreover, biodegradation pathways with the involvement several dechlorinated or hydroxylated metabolites were proposed for examined compunds. Concentration-dependent shifts in oxidative stress enzymes activity and slight modifications in phospholipid profiles were noted for the tested PBAT concentrations. In summary, this study enhances our understanding of PBAT's impact on the physiology of filamentous fungal and their degradative capacities important for mitigating environmental pollution by xenobiotics and plastics. [Display omitted] • The toxicity of PBAT microparticles is concentration-dependent. • Fungi show varying levels of sensitivity in different culturing conditions. • Trichoderma sp. is capable of degrading PBAT. • The presence of PBAT can impact the herbicide degradation process. • Trichoderma sp. is able to absorb microplastic into cells. [ABSTRACT FROM AUTHOR]

Objective: Unusual clinical course Background: Metolachlor is a chloroacetamide herbicide that is extensively used worldwide. Ingestion of metolachlor causes acute toxicity via the generation of methemoglobin. Elevated levels of methemoglobin inhibit the transport of oxygen to tissue, causing hypoxia and lactic acidosis. A common treatment approach has been to reduce methemoglobin by administration of methylene blue. Herein, we present a case of metolachlor poisoning causing lactic acidosis that was treatable by thiamine administration, in which the methemoglobin level was not elevated. Case Report: A 61-year-old man was admitted to the emergency room with seizures and impaired consciousness after the ingestion of metolachlor (250 mL, 83%) with the intent to commit suicide. The patient's methemoglobin and lactate levels on admission were 0.9% and 11.8 mmol/L, respectively. After admission, the levels of lactate decreased gradually; however, they increased 13 h after admission. There was no evidence of heavy alcohol consumption, hyponutrition, or chronic thiamine deficiency. We initially administered a thiamine bolus (100 mg), which immediately improved his consciousness, followed by continuous administration of the same substance (1500 mg/day). The patient's consciousness improved, and was discharged from the intensive care unit on day 4. Conclusions: Metolachlor can cause metabolic dysfunction and lactic acidosis without an increase in methemoglobin. Moreover, thiamine administration may be beneficial for patients with metolachlor intoxication exhibiting symptoms of elevated lactate levels, impaired consciousness, and lack of elevated methemoglobin levels. [ABSTRACT FROM AUTHOR]

Walnut shell biochar (WBC) was used to adsorb metolachlor (MET) in soils with different kaolin contents. 0%, 10%, and 20% of kaolin were added to the pretreated soil to prepare experimental soil. Adsorption kinetics, pH value, adsorbent dosage, ionic strength, and isotherm adsorption models are all used to characterize the adsorbent, and the removal effects of WBC on MET in different experimental soils were studied. The saturation adsorption capacities of MET on WBC in the soil with 0%, 10%, and 20% kaolin are 39.38, 44.44, and 52.08 mg g−1 , respectively, according to the fitting findings of the Langmuir isotherm model. In the experiment, the kaolin can increase the adsorption of MET by the soil itself and promote the MET adsorption by WBC. This study provides a theoretical basis for minerals' influence on the adsorption of biochar under natural conditions. [ABSTRACT FROM AUTHOR]

We developed, tested, and optimized two laboratory denitrification assays for both managers and scientists to assess the effects of xenobiotics on the denitrification process over 7 days (short batch assay, SBA) and 28 days (long semi-continuous assay, LSA). The assays facilitate (1) measuring the efficiency of nitrate removal under the influence of xenobiotics, (2) determining the removal of the tested xenobiotics via adsorption or biotic decomposition, and (3) testing the influencing parameters for optimizing the denitrification process. The adsorption of the xenobiotics was assessed by inhibiting all biological processes through the addition of HgCl2. Our tests demonstrate that the ratio of the initial nitrate concentration to the amount of bioavailable organic matter provided is essential to avoid organic carbon or nitrate limitation. While a pH < 7 resulted in decreased denitrification, a pH > 8 led to nitrite accumulation, indicating incomplete denitrification. Over durations of more than a week, weekly replenishments of the nitrate and HgCl2 and weekly purging with argon gas to reduce the oxygen concentrations are needed. The assays provide information about the accumulation of xenobiotics in the bioreactors that is necessary for the environmentally friendly treatment of the bioreactor fillings and provide insight into the potential of the bioreactors to remove pesticides from polluted water resources.

In order to improve the labor-saving degree of chemical control of weeds in rice fields and reduce the cost of weed control, metolachlor + bensulfuron-methyl 20% effervescent tablets were prepared by the dry pressing process. The type and dosage of adjuvants in the formulation were selected by the single variable method, and the field efficacy of the prepared effervescent tablets was evaluated. The results showed that the optimal formulation (mass fraction) of metolachlor + bensulfuron-methyl 20% effervescent tablets was: 16% metolachlor, 4% bensulfuron-methyl, 18% organobentonite, 9% white carbon black, 20% tartaric acid, 20% sodium bicarbonate, 6% EFW, 4% G202 and 3% magnesium stearate. The effervescent tablets could effectively control weeds in the rice field in the dosage range of 120-180 g/hm² of active ingredients, and its control efficacy was significantly better than that of single agent, which was equivalent to that of the registered wettable powder. The duration of control efficacy was more than 40 days. The effervescent tablets prepared in the study had smooth surface, no dust, and remarkable control efficacy against weeds in the rice field, which was worth to be promoted as a convenient and time- and labor-saving pesticide formulation. [ABSTRACT FROM AUTHOR]

Enantioselective antibodies have emerged as great potential biomaterials in the fields of immunoassays and chiral separation. However, cross-reactivity of antibodies to the distomer may severely restrict the application. Comprehending the interaction mechanism between antibodies and enantiomers could be beneficial to produce superior enantioselective antibodies. In this study, a pair of recombinant antibodies (RAbs) against metolachlor enantiomers at chiral carbon (αSS-MET and αSR-MET) were generated and characterized. The αSS-MET-RAb and αSR-MET-RAb showed comparable sensitivity and specificity to the parental monoclonal antibodies by icELISA, with IC 50 values of 3.45 and 223.77 ng/mL, respectively. Moreover, the complex structures of RAbs and corresponding eutomer were constructed and analyzed, and site-specific mutagenesis was utilized to verify the reliability of the enantioselective mechanism elucidated. It demonstrated that the strength of the interaction between the chiral center region of eutomer and the antibody was the key factor for the enantioselectivity of antibody. Increasing this interaction could limit the conformational adjustment of the distomer in a specific chiral recognition cavity, thus decreasing the affinity of the antibody to the distomer. This work provided the in-depth analysis of enantioselective mechanism for two RAbs and paved the way to regulate antibody enantioselective performance for immunoassays of chiral compounds. [ABSTRACT FROM AUTHOR]

Due to the widespread use of metolachlor (MET), the accumulation of MET and its metabolites in the environment has brought serious health problems to aquatic organisms. At present, the toxicity of MET on the physiological metabolism of aquatic animals mainly focused on the role of enzymes. There is still a lack of research on the molecular mechanisms of MET hepatotoxicity, especially on antagonizing MET toxicity. Therefore, this study focuses on grass carp hepatocytes (L8824 cells) closely related to toxin accumulation. By establishing a MET exposed L8824 cells model, it is determined that MET exposure induces pyrolytic inflammation of L8824 cells. Subsequent mechanistic studies found that MET exposure induces pyroptosis in L8824 cells through mitochondrial dysfunction, and siCaspase-1 inhibits the MET induced ROS production, suggesting a regulation of ROS-NLRP3- Caspase-1 pyroptotic inflammation cycling center in MET induced injury to L8824 cells. Molecular docking revealed a strong binding energy between melatonin (MT) and Caspase-1. Finally, a model of L8824 cells with MT intervention in MET exposure was established. MT can antagonize the pyroptosis induced by MET exposure in L8824 cells by targeting Caspase-1, thereby restoring mitochondrial function and inhibiting the ROS-pyroptosis cycle. This study discovered targets and mechanisms of MT regulating pyroptosis in MET exposed-L8824 cells, and the results are helpful to provide new targets for the design of MET antidotes. [Display omitted] • 400 μM MET exposure induces 60% of L8824 undergo pyroptosis. • MET exposure activates pyroptosis by impairing mitochondrial function of L8824. • Caspase-1 plays a key role in MET exposure induced-pyroptotic inflammatory of L8824. • MT targeting Caspase-1 antagonizes MET exposure induced-ROS/pyroptosis cycle in L8824. [ABSTRACT FROM AUTHOR]

[Display omitted] • Selective and sensitive method was developed for acetochlor and metolachlor quantification by HPLC-UV. • Vortex-assisted dispersive liquid–liquid microextraction procedure was optimized. • Optimized methods provided good repeatability (RSD < 10 %) and high recoveries (>80 %). • Optimized DLLME enabled the quantification of acetochlor and metolachlor at levels as low as 3–4 µg/L. In this study, we developed a method that is sensitive, simple, and environmentally friendly for quantifying acetochlor and metolachlor. This method combines vortex-assisted dispersive liquid–liquid microextraction (DLLME) with high-performance liquid chromatography (HPLC). HPLC operating parameters and extraction parameters for direct and post-extraction analyses of acetochlor and metolachlor were optimized by employing the Taguchi experimental design method. The optimized HPLC parameters for acetochlor and metolachlor were 1.00 mL/min and 1.2 mL/min flow rate, 40 °C column temperature, and 70/30 (ACN/Water) and 80/20 (ACN/Water) at 210 and 230 nm wavelengths, respectively, for the direct injection method. For the DLLME procedure, 1,2-dichloroethane extraction solvent type, acetonitrile, and methanol dispersive solvent type, 400 µL and 300 µL extraction solvent volumes, and 1.0 mL dispersive solvent volume were the optimized DLLME extraction parameters, respectively. The developed and optimized methods for acetochlor and metolachlor analyses exhibited satisfactory validation results, with excellent linearity, indicated by R2 values greater than 0.99. The limit of detection (LOD) and the limit quantification (LOQ) levels of acetochlor and metolachlor were 28.96 to 31.25 µg/L, and 86.87 to 93.75 µg/L for direct injection, and 1.15 to 1.24 µg/L and 3.47 to 3.75 µg/L for post-extraction, respectively. The DLLME recovery values were within the range of 82.6–99.2 % (relative standard deviations-RSD: 4.47–10.13 %) for acetochlor and 91.1–103.4 % (4.31–7.96 %) for metolachlor. Repeatability and reproducibility results (n = 10) of direct injection and post-extraction methods for fortified acetochlor and metolachlor samples displayed very high precision lower than 2 % RSD. [ABSTRACT FROM AUTHOR]

Nanoparticle incorporated membranes are potential tools to remove hazardous organic pollutants from drinking water sources. Cellulose acetate membranes were impregnated by incorporating zinc nanoparticles, produced using a green synthesis with Mentha plant extract utilizing microwave energy. The synthesized nanoparticles were extensively characterized using ultraviolet–visible spectroscopy, X-ray diffraction, Scanning electron microscopy, energy dispersive X-ray spectroscopy and Nanoparticle tracking analysis. The spectroscopy results showed an absorbance peak at 300 nm, confirming the successful synthesis, while X-ray diffraction confirmed that the particles are crystalline with a mean particle size of 36 nm. The surface roughness and topography of the zinc nanoparticle impregnated membranes was studied using atomic force microscopy to check the homogeneity of dispersion of the nanoparticles in the membrane. The efficiency of the zinc nanoparticles and the zinc nanoparticle loaded cellulose acetate membranes for adsorption of organic herbicides such as metolachlor and acetochlor was studied. The particles themselves and the particle-embedded membranes proved to be very adsorbent due to their unique structural properties, providing large surface area and high adsorption capacity. The incorporation of zinc nanoparticles into the membrane decreased the time needed for the removal of the selected herbicides relative to that of the nanoparticles alone, and provides a promising method for water purification.

Enantioselective antibodies have emerged as efficient tools in the field of chiral chemical detection and separation. However, it is complicated to obtain a highly stereoselective antibody due to the unclear recognition mechanism. In this study, the hapten of metolachlor was synthesized and enantio-separated. The absolute configuration of the four haptens obtained was identified by the computed and experimental electronic circular dichroism comparison. Five polyclonal antibodies against the Rac-metolachlor and its enantiomers were generated by immunization. The cross-activity of all the 5 antibodies with 44 structural analogues, including metolachlor enantiomers, was tested. It demonstrated that antibodies have higher specificity to recognize central chirality than axial chirality. Especially, αRR-MET-Ab exhibited excellent specificity and stereoselectivity. Accordingly, 3D-QSAR models were constructed and revealed that paired stereoisomers exhibited opposite interactions with the antibodies. It is the first time that the antibodies against four stereoisomers were prepared and analyzed, which will be conducive to the rational design of the stereoselective antibodies.

Background: Tree bark measurements conducted between 2014 and 2017 in a biosphere reserve in Germany have indicated the presence of pesticides from conventional agriculture in ambient air. In the present study, we quantified pesticides and related substances in ambient air at 69 sites using passive air samplers and ventilation filter mats. It is, to our knowledge, so far the most comprehensive data set on pesticides and their related products in ambient air in Germany. Results: Samples were collected in 2019 and analysed for over 500 substances. One hundred and nine (109) were detected, including 28 that are not approved for use in Germany. In each sampling site, we identified one to 36 substances, including locations such as national parks and forests. Here, the presence of pesticides is not expected, e.g., on the highest mountain top in the national park "Harz" (13 substances) and in the "Bavarian Forest" (six substances). Glyphosate was recorded in every sample. More than half of passive air samplers contained chlorothalonil, metolachlor, pendimethalin, terbuthylazine, prothioconazole-desthio, dimethenamid, prosulfocarb, flufenacet, tebuconazole, aclonifen, chlorflurenol, hexachlorobenzene (HCB), and γ-hexachlorocyclohexane (γ-HCH). Filter mats also contained boscalid. The statistical analysis showed that landscape classification and agricultural intensity were the primary factors influencing the number of substances detected in ambient air. Location, such as protected areas or regions of organic farming, had only a small effect on the number of substances recorded. Medium- and long-range transport likely accounts for these findings. Extending the current sampling method will probably detect more pesticides than the data currently suggest. Conclusions: Airborne pesticide mixtures are ubiquitous in Germany, which is particularly concerning for glyphosate, pendimethalin, and prosulfocarb. Deposition of these pesticides on organic products may disqualify them from the market, resulting in economic losses to farmers. Air concentrations of pesticides are a relevant issue and must be reduced. [ABSTRACT FROM AUTHOR]

The effects of many pesticides on aquatic ecosystems remain poorly understood, especially in naturalistic communities in which organisms are connected by a complex array of direct and indirect interactions. Moreover, multiple stressors can interact, and the addition of apex predators, such as fish, may introduce additional ecosystem changes that exacerbate or mitigate pesticide effects. Despite being both common and environmentally persistent, the effects of the herbicide metolachlor on realistic aquatic communities have received insufficient research attention. We tested the effects of metolachlor on pond mesocosms at three concentrations (0, 20, and 80 ppb), along with the presence vs. absence of fish (black crappie, Pomoxis nigromaculatus) to determine the independent and combined effects of these two environmental changes. We found both metolachlor and fish altered the pond mesocosms, but their effects did not interact. Metolachlor reduced phytoplankton as expected, but had nonlinear effects on dissolved oxygen. Metolachlor also altered tadpole behavior, making them less prone to hiding. Fish presence increased periphyton and decreased snail counts, as well as changing the behavior of tadpoles, reducing their hiding behavior. This work demonstrates previously undocumented effects of metolachlor in the presence and absence of fish and suggests future avenues of investigation. [ABSTRACT FROM AUTHOR]

In this study, we investigated the removal of metolachlor (MET) by biochar (BC) prepared from walnut shells (W-BC) compared with BCs made from cow dung (D-BC) and corn cobs (C-BC) by characterizing the adsorption kinetics, pH, adsorbent dose, and ionic strength, and using isotherm models. Weight analysis was also conducted to understand the adsorption capacity and adsorption mechanisms. The results showed that the MET removal rates were 87.89% (W-BC), 52.91% (D-BC), and 10.91% (C-BC), respectively. According to the results fitted to the Langmuir isotherm model, the saturated adsorption capacities for MET were 96.15 mg g−1, 37.88 mg g−1, and 11.98 mg g−1 with W-BC, D-BC, and C-BC, respectively. The results demonstrated that W-BC was particularly effective at MET removal. Analyses based on the weights of different factors showed that the correlation coefficient was highest for the BC type with 46.11% in the MET adsorption process, followed by the initial concentration of MET (19.29%). The adsorption of MET by BCs was probably influenced mostly by electron donor–acceptor interactions and pore filling. These results may facilitate further studies of the adsorption mechanism and optimization of the process. [ABSTRACT FROM AUTHOR]

Featured Application: The use of pre-emergent (or residual) herbicides like metolachlor has increased dramatically worldwide as an option to manage herbicide-resistant biotypes, as they suppress weed seed emergence from the soil. Hence, there is an emerging interest in comprehending its persistence and fate in cropping systems. Recurring flooding events and the consequent anoxic conditions in agro-ecosystems are ubiquitously present and inevitable. However, much less is known about the environmental fate of a popular herbicide like metolachlor in such soil environmental conditions. Hence, in this paper, we explored the impacts of the aerobic and anaerobic soil conditions of the environmental fate of 14C-labeled metolachlor by using radioactive analytical techniques. This article contributes to better understanding the behavior of a globally utilized plant protection chemical like metolachlor in soils. The information generated could be applied for the efficacious and judicious use of metolachlor or similar herbicides in crop production systems. The impact of the aeration status of soils on the environmental fate of the soil-applied pre-emergent herbicide metolachlor is of significance to sustainable agriculture practices and has not been investigated thoroughly by existing research works. To address this knowledge gap, we examined the adsorption, desorption, degradation, and mineralization of radioactively labeled [14C] metolachlor in Catlin, Flanagan, and Drummer soils under aerobic and anaerobic conditions. Based on our findings, anaerobic conditions in the soil significantly reduced the adsorption of 14C-metolachlor while also promoting its desorption, thereby potentially releasing a greater amount of herbicide from the soil after a field application. The first-order degradation and mineralization kinetics of 14C-metolachlor were distinctively enhanced by anaerobic conditions in all the soils tested. Furthermore, the degradation and mineralization rates of 14C-metolachlor in non-sterilized versus sterilized soil microcosms clearly indicated microbial activity in the degradation of metolachlor in soil. The results from this study suggest that soil redox conditions could impact the bioavailability and environmental fate of herbicide metolachlor and should be taken into consideration as part of sustainable weed management programs. [ABSTRACT FROM AUTHOR]

Three activated carbons from lignocellulosic residues and a commercial carbon have been tested for the removal of the herbicide metolachlor and its two degradation transformation products, named ESA and OXA, in aqueous solutions. The kinetics and equilibrium adsorption were studied for the four materials, showing higher adsorption capacities for the three molecules on the carbon materials chemically activated by potassium carbonate, mainly associated with its greater porous development, especially in the range of microporosity. Additionally, the chemical composition of the adsorbents also highlighted their important influence on the ESA and OXA adsorption process. The efficient adsorption of both compounds—even at low initial concentrations—allows a removal efficiency of up to 80% to be reached, revealing promising perspectives for the use of biomass-derived carbon materials for the elimination of not only the herbicide metolachlor, but also its degradation compounds from contaminated wastewater. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the stability and toxicity of the herbicides and their degradation byproduct after exposure to different environmental factors. Triazines (atrazine, propazine, simazine) and chloroacetanilides (acetochlor, alachlor, metolachlor) which are commonly used herbicides were evaluated for cytotoxicity in different UV (254 nm and 365 nm) and temperature (4 °C, 23 °C, and 40 °C) conditions as well as degradation rates. Atrazine with the highest LD50 (4.23 μg mL−1) was less toxic than the other tested triazine herbicides Chloroacetanilides tested were more toxic than tested triazines, with LD50 0.08–1.42 μg mL−1 vs 1.44–4.23 μg mL−1, respectively. Alachlor with LD50 0.08 μg mL−1 showed the strongest toxic response as compared with other tested herbicides. Temperatures only did not alter cytotoxicity of the tested herbicides, except for acetochlor and alachlor showing about 45 % more cell death after exposure to 40 °C for 2 h. At all 3 tested temperatures, 2 h of UV treatments did not affect cytotoxic effects of the tested herbicides, except for acetochlor and alachlor. At 4 °C, acetochlor toxicity was attenuated about 63 % after UV 365 nm exposure; but alachlor toxicity was enhanced after either UV 254 or 365 nm exposure for about 40 % and 24 %, respectively. At 23 °C, acetochlor toxicity was enhanced about 35 % after UV 254 nm exposure, but attenuated about 48 % after UV 365 nm exposure. Alachlor toxicity was enhanced about 34 % after UV 254 nm and 23 °C exposure. In combination of UV 254 nm and 40 °C, acetochlor toxicity was lowered by 63 % and alachlor toxicity was no change as compared with 4 °C, no UV group. After co-treatment with UV 365 nm and 40 °C both acetochlor and alachlor toxicity was enhanced 55 % and 80 %, respectively. Through degradation analysis by LC-MS/MS, alachlor showed the most dramatic degradation (only 0.58 %–10.58 % remaining) after heat and UV treatments.

A sensitive micellar-enhanced thermochemically induced fluorescence derivatization (ME-TIFD) method for a rapid determination of metolachlor (MET) residues based on the O-phthalaldehyde (OPA)-thermoproduct complex of MET (OPA-MET) was investigated. Both SDS and Brij-700 have been used as surfactant micelles. This study advocates the TIFD method analytical parameters curation. Fluorescence enhancement and its stabilization were highlighted for the OPA-MET equimolar complex in micellar aqueous solutions. The new analytical features (K: binding constant and ΔG°: Gibbs energy) for controlling thermodynamic interactions were carried out at 25 °C. Under the optimized conditions, the calibration curves were linear with correlation coefficients ranging from 0.9788 to 0.9896 at the concentration level of 10-580 ng mL–1, and the limits of detection were 0.04-0.7 ng mL−1 at a signal-to-noise (S/N) of 3. The SPE/ME-TIFD applications combined with analysis of well and tap water spiked samples with metolachlor yield satisfactory mean recoveries (RSD) 102.2–108.1% (5.1–7.3%) and 103.6–106.0% (6.3–7.6%), respectively.

While there has been intensive research on the influence of microplastics (MPs) on aquatic organisms and humans, their effect on microorganisms is relatively little-known. The present study describes the response of the Trichoderma harzianum strain to low-density polyethylene (LDPE) microparticles. MPs, either separately or with metolachlor (MET), were added to the cultures. Initially, MP was not found to have a negative effect on fungal growth and MET degradation. After 72 h of cultivation, the content of fungal biomass in samples with MPs was almost three times higher than that in the cultures without MPs. Additionally, a 75% degradation of the initial MET was observed. However, due to the qualitative and quantitative changes in individual classes of phospholipids, cell membrane permeability was increased. Additionally, MPs induced the overproduction of reactive oxygen species. The activity of superoxide dismutase and catalase was also increased in response to MPs. Despite these defense mechanisms, there was enhanced lipid peroxidation in the cultures containing the LDPE microparticles. The results of the study may fill the knowledge gap on the influence of MPs on filamentous fungi. The findings will be helpful in future research on the biodegradation of contaminants coexisting with MPs in soil.

Core Ideas: All of the 120 accessions of Palmer amaranth collected in the Coastal Plain of North Carolina were controlled by atrazine and dicamba applied at field use rates in the greenhouse.Reduced sensitivity among accessions was noted when S‐metolachlor and 2,4‐D were applied to Palmer amaranth at field use rates in the greenhouse.Additional research is needed to determine if reduced sensitivity of Palmer amaranth to S‐metolachlor and 2,4‐D is associated with evolved resistance. [ABSTRACT FROM AUTHOR]

Atrazine is a foundational herbicide in corn (Zea mays L.) because of its broad‐spectrum weed control and utility for pre‐emergence or postemergence applications. Extensive atrazine use has led to traces in groundwater, surface water, and aquifers. This research explored corn herbicide regimes with little or no atrazine. Pre‐emergence herbicide treatments [S‐metolachlor (0.955 lb acre–1); saflufenacil (0.054 oz acre–1) plus dimethenamid‐P (0.473 lb acre–1)] and postemergence herbicide mixtures [bicyclopyrone (0.040 lb acre–1) plus mesotrione (0.161 lb acre–1) plus S‐metolachlor (1.429 lb acre–1); thiencarbazone‐methyl (0.013 lb acre–1) plus tembotrione (0.067 lb acre–1), thiencarbazone‐methyl (0.033 lb acre–1) plus isoxaflutole (0.082 lb acre–1); acetochlor (0.964 lb acre–1) plus mesotrione (0.103 lb acre–1) plus clopyralid (0.065 lb acre–1)] were applied alone or combined with atrazine at 0.50 lb acre–1 to glyphosate‐ or glufosinate‐resistant corn. All postemergence applications contained glyphosate (1.125 lb acre–1) plus glufosinate (0.402 lb acre–1). Palmer amaranth [Amaranthus palmeri (S.) Watson], broadleaf signalgrass [Urochloa platyphylla (Munro ex C. Wright) Nash], and pitted morningglory (Ipomoea lacunosa L.) control were always greater than 95%. Saflufenacil plus dimethenamid‐P injured corn 8 and 5% more than S‐metolachlor 21 d after pre‐emergence application. Averaged over pre‐emergence herbicide and atrazine rate, thiencarbazone‐methyl plus isoxaflutole injured corn by 21% in 2017. The addition of atrazine did not improve corn yield in 7 of 16 instances. According to this research, the weeds assessed at these densities can be controlled without atrazine by some programs. Core Ideas: Weed control programs with and without postemergence atrazine were examined.Corn exhibited adequate tolerance to the herbicide programs evaluated.Effective herbicide programs were identified in the absence of atrazine.Several herbicide programs without atrazine allowed corn yields comparable with its use. [ABSTRACT FROM AUTHOR]

Metolachlor (MET) is a widely used herbicide that can adversely affect phytoplanktonic non-target organisms, such as cyanobacteria. Chytrids are zoosporic fungi ubiquitous in aquatic environments that parasitize cyanobacteria and can keep their proliferation in check. However, the influence of organic pollutants on the interaction between species, including parasitism, and the associated ecological processes remain poorly understood. Using the host-parasite system consisting of the toxigenic cyanobacterium Planktothrix agardhii and its chytrid parasite Rhizophydium megarrhizum , we investigated the effects of environmentally relevant concentrations of MET on host-parasite interactions under i) continuous exposure of chytrids and cyanobacteria, and ii) pre-exposure of chytrids. During a continuous exposure, the infection prevalence and intensity were not affected, but chytrid reproductive structures were smaller at the highest tested MET concentration. In the parasite's absence, MET promoted cyanobacteria growth possibly due to a hormesis effect. In the pre-exposure assay, MET caused multi- and transgenerational detrimental effects on parasite fitness. Chytrids pre-exposed to MET showed reduced infectivity, intensity, and prevalence of the infection, and their sporangia size was reduced. Thus, pre-exposure of the parasite to MET resulted in a delayed decline of the cyanobacterial cultures upon infection. After several parasite generations without MET exposure, the parasite recovered its initial fitness, indicating that detrimental effects are transient. This study demonstrates that widely used herbicides, such as MET, could favor cyanobacterial bloom formation both directly, by promoting cyanobacteria growth, and indirectly, by inhibiting their chytrid parasites, which are known to play a key role as top-down regulators of cyanobacteria. In addition, we evidence the relevance of addressing multi-organism systems, such as host-parasite interactions, in toxicity assays. This approach offers a more comprehensive understanding of the effects of pollutants on aquatic ecosystems. [Display omitted] • Continuous exposure to MET stimulated cyanobacterial growth. • Infection prevalence and intensity were not affected by continuous exposure to MET. • Pre-exposure of chytrids to MET delayed cyanobacterial decline. • MET decreases disease spread over multiple parasite generations. [ABSTRACT FROM AUTHOR]

In this paper, a novel metolachlor microcapsules suspension (CS) was prepared by interfacial polymerization. Metolachlor polyurea microcapsules suspension was successfully prepared by urea instead of polyamines which could reduce the use of organic solvents and production costs. The synthesized microcapsules were characterized by Fourier Transform Infrared Spectrometer, Scanning Electron Microscope, Ultraviolet Spectrometry, Thermogravimetric analyses and particle size analyzer. In conclusion, the diameter of the urea microcapsules were the smallest (11.52 μm) and excellent encapsulation efficiency (81.45%). In addition, Urea microcapsules had compact microstructures and global shapes, which had a good thermal stability and metolachlor could be preserved better in the polyurea microcapsules. These results indicated that the prepared microcapsules by urea had better thermal storage properties and physicochemical property. The microcapsule suspension of metolachlor hasn’t been researched yet. Therefore, it is significant to prepare microcapsule suspension. More importantly, there is no use of organic solvents in the preparation of microcapsules suspension, which avoided the pollution of solvents to the ecological environment. It is hoped that this polyurea material will be applied in the field of pesticide synthesis and polymers.

Metolachlor is extensively used and the most persistent chloroacetamide herbicide, thereby which its metabolites have been frequently detected in soils and surface and groundwaters. Microbial degradation is predominantly responsible for the removal of metolachlor from soil and water. However, few microbial strains reported previously are highly efficient in degrading potentials for metolachlor. We isolated the fungal strain MET-F-1 from an activated sludge, characterized as Penicillium oxalicum, which could degrade 88.6% of 50 mg/L metolachlor coupled with 0.1% glucose plus 0.1% yeast extract within 384 h under optimal conditions. Compared with metabolites produced by previously isolated microorganisms, different degradation products, i.e., MOXA, M2H, and MDES, detected by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), were produced through hydrolytic and reductive dechlorination by MET-F-1. This is the first report on the degradation of metolachlor by Penicillium oxalicum sp. Furthermore, field plot experiments using the wheat bran inoculum method were performed and demonstrated good metolachlor-degrading activity of this strain. This study serves as a steppingstone to promote MET-F-1 strain usage as a promising agent for metolachlor-contaminated soil remediation. [ABSTRACT FROM AUTHOR]

Herein, the facile one step acid activation of bentonite derived functionalized adsorbent (AB) for the effective remediation of both ionic and non-ionic secondary pesticides, ametryn and metolachlor has been attempted. The surface characteristics of AB were examined by the nitrogen adsorption–desorption analysis, scanning electron microscopy (SEM), and Fourier Transforms Infrared (FTIR) Spectroscopy. The adsorptive behavior was evaluated with respect to the effect of contact time, initial concentrations and solution pH. The equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models, while the adsorption kinetic was analyzed using the pseudo-first order and pseudo-second order kinetic equations. Thermodynamic parameters including the standard enthalpy change (ΔH°), standard entropy change (ΔS°), and Gibbs free energy change (ΔG°) were established. Thermodynamic analysis illustrated that the adsorption process was feasible and exothermic in nature, while the characterization findings verified the alteration of FTIR bands, and a high specific surface area of 464.92 m2/g, with a series of pores distributed over the surface. Equilibrium data was best confronted to the pseudo-second order kinetic model, while the adsorptive removal of ametryn and metolachlor onto AB was satisfactory described by the Langmuir isotherm model, with the monolayer adsorption capacities for ametryn and metolachlor of 2.032 and 0.208 mmole/g respectively. The findings outlined the potential of the newly develop AB for the on-site treatment of pesticide polluted water. [ABSTRACT FROM AUTHOR]