Degradation Of Chlorothalonil Research Articles

Enhanced electrocatalytic elimination of fenitrothion, trifluralin, and chlorothalonil from groundwater and industrial wastewater using modified Cu-PbO2 electrode

In this study, fenitrothion (FTH), trifluralin (TRL), and chlorothalonil (CHT) pesticides were studied as simultaneous degradation candidates for the anodic oxidation (AO) process. Characterization experiments including FE-SEM, XRD, cyclic voltammetry, electrochemical impedance spectroscopy, linear polarization, and accelerated service lifetime test (ASLT) were performed to evaluate the effect of Sn@Sb, PbO2, and PbO2/Cu electrodes. The doping of Cu into PbO2 electrode played an important role in improving the electro-catalytic activity of the electrode and can further increase the •OH generation capacity. Simultaneous removal FTH, TRL, and CHT using the AO process was optimized by response surface methodology. Analysis of variance revealed that the R2 of removal efficiency for FTH, TRL, and CHT were 0.9848, 0.9791, and 0.9770, respectively. Moreover, the adjusted R2 for degradation of FTH, TRL, and CHT were 0.9822, 0.9756, and 0.9738, and the predicted R2 were 0.9770, 0.9694, and 0.9685, respectively. The complete removal efficiency for FTH, TRL, and CHT was achieved under the optimal condition including FTH concentration 8.0 mg L−1, TRL concentration 12.0 mg L−1, CHT concentration 16.0 mg L−1, pH 6.0, current density 6.0 mA cm−2, and oxidation time of 60 min. In the optimum condition COD removal efficiency and energy consumption were 74.3% and 4.4 kWh m−3 using PbO2/Cu electrode, respectively. The kinetic of FTH, TRL, and CHT degradation on Sn@Sb, PbO2, and PbO2/Cu electrodes best fitted on a pseudo-first-order kinetic model. The oxygen evolution overpotential was 1.914, 1.983, and 2.138 V vs. SCE for Sn@Sb, PbO2, and PbO2/Cu electrodes, respectively. The ASLT of PbO2/Cu electrode is 344 h, which is 2.3 and 4.2 times longer than that of PbO2 and Sn@Sb electrodes. The degradation mechanism was evaluated using GC–MS technique and a possible degradation pathway for the anodic oxidation of FTH, TRL, and CHT was proposed based on the identified intermediates. As a result, the AO technology using PbO2/Cu electrode could be considered a nice solution to the treatment of pesticides-polluted wastewater.

Jasmonic acid promotes glutathione assisted degradation of chlorothalonil during tomato growth

Glutathione (GSH) biosynthesis and regeneration play a significant role in the metabolism of chlorothalonil (CHT) in tomatoes. However, the specific regulatory mechanism of GSH in the degradation of CHT remains uncertain. To address this, we investigate the critical regulatory pathways in the degradation of residual CHT in tomatoes. The results revealed that the detoxification of CHT residue in tomatoes was inhibited by buthionine sulfoximine and oxidized glutathione pretreatment, which increased by 26% and 46.12% compared with control, respectively. Gene silencing of γECS, GS, and GR also compromised the CHT detoxification potential of plants, which could be alleviated by GSH application and decreased the CHT accumulation by 33%, 25%, and 21%, respectively. Notably, it was found that the jasmonic acid (JA) pathway participated in the degradation of CHT regulated by GSH. CHT residues reduced by 28% after application of JA. JA played a role downstream of the glutathione pathway by promoting the degradation of CHT residue in tomatoes via nitric oxide signaling and improving the gene expression of antioxidant and detoxification-related enzymes. This study unveiled a crucial regulatory mechanism of GSH via the JA pathway in CHT degradation in tomatoes and offered new insights for understanding residual pesticide degradation.

Effect of Water pH and Direct Exposure to Sunlight on Chemical Stability of Fungicide Chlorothalonil

This project target aim to investigate the hydrolysis of fungicide chlorothalonil at different pH solutions at (pH4, pH7, and pH9), as well as its stability under exposure to different temperature degrees and direct exposure to sunlight, and to estimate the photoproducts degradation of chlorothalonil using GC/MS. The data showed that chlorothalonil dissipation from different pH solutions increased more rapidly with increasing both pH value and temperature when compared to acidic and neutral solutions, and that tested pesticides were hydrolyzed more rapidly in alkaline media (PH9) than the other tested pH values at all tested temperatures. The percentage of pesticides that decompose steadily increases and is positively connected with exposure times, according to the data. The results also demonstrated that after 336 hours of exposure to direct sunlight, no detectable level of the pesticides tested was found. The compound (4-hydroxy-2,5,6-trichloroisophthalonitrile) was identified as a major metabolites in environmental samples after photo-degradation products were investigated using GC/MS following exposure to direct sunlight.

Regulation of chlorothalonil degradation by molecular hydrogen

Pesticides can accumulate throughout the food chain to potentially endanger human health. Although molecular hydrogen (H2) is widely used in industry and medicine, its application in agriculture is just beginning. This study showed that H2 enhances the degradation of the fungicide chlorothalonil (CHT) in plants, but does not reduce its antifungal efficacy. Pharmacological evidence confirmed the contribution of H2-stimulated brassinosteroids (BRs) in the above responses. The genetic increased endogenous H2 with overexpression of hydrogenase 1 gene (CrHYD1) from Chlamydomonas reinhardtii in Arabidopsis not only increased BRs levels, but also eventually intensified the degradation of CHT. Expression of genes encoding some enzymes responsible for detoxification in tomato and Arabidopsis were also stimulated. Contrasting responses were observed after the pharmacological removal of endogenous BR. We further proved that H2 control of CHT degradation was relatively universal, with at least since its degradation in Chinese cabbage, cucumber, radish, alfalfa, rice, and rapeseed were differentially enhanced by H2. Collectively, above results clearly indicated that both exogenously and endogenously applied with H2 could stimulate degradation of CHT partially via BR-dependent detoxification. These results may open a new window for environmental-friendly hydrogen-based agriculture.

Effects of combined treatment of plasma activated liquid and ultrasound for degradation of chlorothalonil fungicide residues in tomato

The effects of combined treatment (PAL-U) of plasma-activated liquid (PAL) including plasma-activated water (PAW) and plasma-activated buffer solution (PABS) and ultrasound (U) for the degradation of chlorothalonil fungicide on tomato fruit was investigated. Distilled water and buffer solution were activated by radiofrequency plasma jet for durations of 1, 3, 5, and 10 min to obtain PAL1 to PAL10. Fruits were immersed in PAL for 15 min and also in distilled water with sonication for 15 min for individual treatments, and in PAL with sonication for 15 min for combined treatments. The maximum chlorothalonil fungicide residues were reduced by 89.28 and 80.23% for PAW10-U and PABS10-U, respectively. HPLC-MS characterization revealed chlorothalonil degradation pathway and formation of 2,4,5-trichloroisophthalonitrile, 2,4-dichloroisophthalonitrile, 4-chloroisophthalonitrile, isophthalonitrile and phenylacetonitrile as degradation products. Treatments also showed no negative effects on tomato quality. Therefore, PAL and PAL-U treatments could serve as effective methods for degrading pesticides on tomatoes.

Degradation of chlorothalonil via thiolation and nitrile hydration by marine strains isolated from the surface seawater of the Northwestern Pacific

Chlorothalonil, a commonly used chlorinated benzonitrile fungicide, is often detected in various environments, including marine ecosystems, and poses a threat to human health and environmental safety. Although the biodegradation of chlorothalonil via several catabolic pathways has been reported by various kinds of microorganisms, the degradation of chlorothalonil by marine strains, as well as their special catabolic pathways, remain to be studied. In this study, six strains of chlorothalonil-degrading bacteria (Sulfitobacter sp. S-1, Sphingobium sp. P-1, Marinicauda sp. M-1, Erythrobacter sp. E-17, Stakelama sp. P-2 and Oceanicaulis sp. B-1) were screened and characterized from a total of 110 culturable bacterial strains obtained from the surface seawater of the Northwestern Pacific. Sphingobium sp. P-1, showing the highest degrading efficiency among the six degraders, and was thus selected for further investigation. Strain P-1 completely removed 20 mg L−1 of chlorothalonil from mineral salt-carbon medium within 24 h and from seawater within 3 d. During the degradation of chlorothalonil by strain P-1, two metabolites (4-sulfydryl-2,5,6-trichloroisophthalonitrile and 5-cyano-4,6,7-trichloro-2H-1,2-benzisothiazol-3-one) were detected and identified by liquid chromatography–mass spectrometry that suggest a special catabolic pathway of chlorothalonil via thiolation and nitrile hydration in the marine strain P-1.

Preparation of mesoporous potassium phosphotungstate/silicon dioxide photocatalyst and study on degradation of chlorothalonil

Preparation of mesoporous potassium phosphotungstate/silicon dioxide photocatalyst and study on degradation of chlorothalonil

The influence of chlorothalonil on the activity of soil microorganisms and enzymes

As one of the most widely used pesticides in agriculture, chlorothalonil can pose threat to soil ecosystems. Therefore, the impact of this substance on the development of microbiological and biochemical properties of the soil as well as on the growth of spring wheat was evaluated. The study was conducted with two soils (loamy sand with pHKCl 5.6 and sandy loam with pHKCl 7.00), to which fungicide was used in the following doses: 0.00, 0.166 (recommended dose), 1.660, and 16.60 mg kg−1 dry matter of soil (DM of soil). In addition, we determined the effectiveness of fertilizing substances (Lignohumat Super and Bioilsa N 12.5) in the restoration of soil homeostasis and chlorothalonil degradation in the soil. Chlorothalonil caused modifications in the count and biological diversity of soil microorganisms. It stimulated the growth of heterotrophic bacteria and actinobacteria, and inhibited the growth of fungi. This pesticide was a potent inhibitor of dehydrogenase, catalase and acid phosphatase activities. It showed variable effects on urease and alkaline phosphatase. The fungicide also a reduction the yield of dry matter of the aboveground parts of spring wheat. It should, however, be noted that these changes in the soil environment occurred after the introduction of higher doses of chlorothalonil. The fertilizing substances used contributed to enhanced microbial and biochemical activities of soils, while they did not significantly affect plant yields. The Bioilsa N 12.5 preparation was effective in chlorothalonil degradation, while Lignohumat Super reduced the degradation rate of the tested fungicide. Based on the conducted experiment, an ecological risk assessment of chlorothalonil was made by estimating the changes occurring in the soil environment evaluated through the microbiological and biochemical analyses of the soil.

Dissolved oxygen inhibits the promotion of chlorothalonil photodegradation mediated by humic acid

Chlorothalonil (CT) is widely used to control fungal diseases, and it is commonly detected in the environment. Phototransformation is an important process which removes CT from aquatic environments. The kinetics and mechanisms of CT photodegradation in solutions with and without humic acid (HA) were investigated, and the influence of dissolved oxygen (DO) on the photodegradation process was also considered. The rate constant observed in pure water was only 0.017 h−1, but it increased to 0.083 h−1 with 5.0 mgC L−1 of HA present. Reactive species generated by HA were shown to play an important role. Moreover, the degradation of CT was promoted at higher HA concentrations. But higher DO concentrations inhibits CT degradation because of the reaction between DO and excited triplet state CT (3CT*) or HA (3HA*). The contributions of the reactive species tested were in the sequence 3HA* > 1O2 > H2O2/O2− ≈ OH in a nitrogen-saturated system, but in an oxygen-saturated system the order was OH ≈1 O2 > H2O2/O2− > 3HA*. 3CT* was confirmed as the active form of CT during degradation, with 4-hydroxy-chlorothalonil and 2,4,5-trichloroisophthalonitrile as the main products. Compared to direct photodegradation, CT photodegradation mediated by HA can decrease the toxicity of an aquatic environment as demonstrated through tests with Scenedesmus obliquus.

Probiotic strain Stenotrophomonas acidaminiphila BJ1 degrades and reduces chlorothalonil toxicity to soil enzymes, microbial communities and plant roots

Chlorothalonil, a non-systemic and broad-spectrum fungicide, is widely used to control the pathogens of agricultural plants. Although microbial degradation of chlorothalonil is known, we know little about the colonization and degradation capacity of these microbes in the natural and semi-natural soil environments. Therefore, we studied the colonization and detoxification potential of a chlorothalonil degrading Stenotrophomonas acidaminiphila probiotic strain BJ1 in the soil under green conditions. The results from polymerase chain reaction-denaturing gradient gel electrophoresis demonstrated that probiotic strain BJ1 successfully colonized the soil by competing with the native biota. Moreover, the bacterial inoculation stimulated some members of indigenous soil microbial communities. Meantime, the degradation half-life of chlorothalonil decreased from 9.0 to 4.9 days in the soil environment. Moreover, the results from enzymatic activities and micronucleus test of Vicia faba root tips showed that the probiotic strain BJ1 reduced the ecotoxicity and genotoxicity of chlorothalonil in the soil. We suggest that probiotic strains like BJ1 could potentially alleviate the toxic effects of pesticides on soil microbes and plant roots under greenhouse conditions.

Procyanidolic oligomers enhance photodegradation of chlorothalonil in water via reductive dechlorination

Chlorothalonil is an important broad-spectrum fungicide with an annual application rate of above ten thousands of tons of its active ingredient on agricultural crops world-wide. The effect of procyanidolic oligomers on photo degradation of chlorothalonil was investigated under sunlight and artificial lights. Procyanidolic oligomers enhanced photodegradation of chlorothalonil in paddy, reservoir, pond and distilled waters for 1.8, 4.6, 2.7 and 22.8 fold, respectively, relative to the procyanidolic oligomers free control. The mechanism was evidenced as a radical reduction reaction by electron paramagnetic resonance spectroscopy. Upon exposure to high-pressure mercury light, chlorothalonil produced 2,4,5-trichloro-1,3-dicyanobenzene, 2,5-dichloro-1,3-dicyanobenzene and 5-chloro-1,3-dicyanobenzene that were isolated, identified and characterized. Chlorothalonil underwent primarily step-wide photo reductive dechlorination in the presence of procyanidolic oligomers, which avoided the production of the highly toxic 4-hydroxy chlorothalonil. Procyanidolic oligomers possessed strong reductive property to photo reductive dechlorination. The results contributed to understanding of chlorothalonil phototransformation and high potential of using natural product procyanidolic oligomers as an additive to minimize aquatic toxicity and pollution of chlorothalonil.

Biodegradation of chlorothalonil by Enterobacter cloacae TUAH-1

The long-term excessive use of chlorothalonil (CTN) can lead to serious environmental pollution, which presents a cause for concern. Here, we investigated the degradation of CTN by using an effective strain, TUAH-1, which was identified as Enterobacter cloacae according to the morphological approach, 16S rDNA gene sequence and phylogenetic tree analysis. Treatment with TUAH-1 demonstrated that the maximum processing capability was 74 mg CTN per gram dry cells in 48 h under optimum conditions (30 °C–35 °C, pH 7.0). After treatment with 21.3 mg dry cells, the degradation efficiency was 97.4% for 20 mg l-1 CTN in the aqueous phase. Meanwhile, treatment with crude enzyme solution containing 2.0 mg ml-1 protein led to complete degradation of 20.0 mg l-1 CTN within 10 h, which is significantly faster than that of TUAH-1. The results also showed that CTN could not be detected after treatment with 5.68 g TUAH-1 per kg soil for 48 h when the original CTN content in the soil was 10 mg kg-1. After treatment with THAH-1 or its crude proteins, many degradation products were detected by HPLC-MS, suggesting two possible degradation pathways. The mechanism of CTN degradation by TUAH-1 was noted to be multienzymatic catalysis comprising glyceraldehyde-3-phosphate dehydrogenase and glutathione S-transferase.

Preparation, characterization of recyclable ammonia phosphotungstate and degradation of chlorothalonil

Preparation, characterization of recyclable ammonia phosphotungstate and degradation of chlorothalonil

Investigation of Rate of Photo Degradation of Chlorothalonil, Lambda Cyhalothrin, Pentachlorophenol and Chlropysis on Tomato and Spinach

Photo-degradation of common pesticides and herbicides on the surface of tomato fruit and spinach leaves were studied. Samples were spiked with 100 mg/ml of lambda cyhalothrin, chlorothalonil, chlorpyriphos and pentachlorophenol standard solutions in acetone. Thy were air dried for 1 minute and exposed to light of various intensities; sunlight, 40 w, 60 w, 75 w and 100 w bulbs after spreading on the surface of spinach and tomatoes for 15, 30, 45 and 60 minutes and then washed in acetone. The pesticide concentration in the samples was analyzed with a UV Visible spectrophotometer. The rate of degradation of chlorothalonil, lambda cyhalothrin, pentachlorophenol and chlorpyriphos was also calculated and rate constants obtained for each residue. The results obtained indicated that the 100 W bulb degradation ranged from 20-95% for all the molecules in both tomato fruit and spinach leave surface. The residues breakdown followed a 1st order kinetics.

Simultaneous biological-photocatalytic treatment with strain CDS-8 and TiO2 for chlorothalonil removal from liquid and soil

In this study, a novel chlorothalonil (CTN) degrading bacterial strain CDS-8, identified as Pseudomonas sp., was combined with photocatalyst titanium dioxide (TiO2) for the CTN degradation in liquid and soil. After 7day incubation, 90.73% of CTN was removed from mineral salt medium (MSM) by CDS-8 with the optimal condition at pH 7.0 and 30°C. Single biodegradation or photocatalytic degradation could not degrade CTN completely, and many toxic and persistent intermediate metabolites remained. However, simultaneous biological-photocatalytic treatments could markedly remove CTN and reduce the chemical oxygen demand (COD) which could not be removed by single biodegradation or photocatalytic degradation. In MSM, treatment with CDS-8/40mgL−1 TiO2 showed the highest COD removal rate (84.10%). Furthermore, combined CDS-8/TiO2 treatments could effectively degrade CTN in soil. In treatments with CDS-8/20mgkg−1 TiO2 of soil, the maximum CTN removal rate reached 97.55% in turned soils. However, with CDS-8/40mgkg−1 TiO2 of soil, the maximum CTN removal rate (94.94%) was found in static soil. In general, the combined biological-photocatalytic treatments provided a promising alternative candidate for the remediation of CTN-contaminated sites.

Construction and analysis of an intergeneric fusion from Pigmentiphaga sp. strain AAP-1 and Pseudomonas sp. CTN-4 for degrading acetamiprid and chlorothalonil.

Pseudomonas sp. CTN-4 degrades chlorothalonil (CTN) but not acetamiprid (AAP), and Pigmentiphaga sp. strain AAP-1 degrades AAP but not CTN. A functional strain, AC, was constructed through protoplast fusion of two parental strains (Pseudomonas sp. CTN-4 and Pigmentiphaga sp. strain AAP-1) in order to simultaneously improve the degradation efficiency of AAP and CTN. Fusant-AC with eight transfers on plates containing two antibiotics and CTN was obtained. For the purpose of identifying and confirming the genetic relationship between fusant-AC and its parents, randomly amplified polymorphic DNA (RAPD), scanning electron microscopy (SEM), and 16S ribosomal DNA (rDNA) analysis were performed. In toto, RAPD fingerprint analysis produced 194 clear bands with 9 primers, which not only had bands in common with strains CTN-4 and AAP-1, but also had its own novel fusant-specific bands. The genetic similarity indices between fusant-AC and parental strains CTN-4 and AAP-1 were 0.40 and 0.69, respectively. The result of SEM indicated that the cell morphology of fusant-AC differed from both its parents. The fusant strain AC possesses a strong capability for AAP and CTN degradation. At AAP concentration (50-300mgL(-1)), the degradation was achieved within 5h. At the initial dose of 50 and 100mgL(-1) CTN, the percentages reached 96 and 91% over a 36-h incubation period. The present study indicates that the protoplast-fusion technique may have possible applications in environmental pollution control.

Effect of pesticide residues in grapes on alcoholic fermentation and elimination of chlorothalonil inhibition by chlorothalonil hydrolytic dehalogenase

The effect of different kinds of pesticide residues in grapes on alcoholic fermentation by Saccharomyces cerevisiae was evaluated. Among four types of pesticides added into the grape slurry, omethoate, triadimefon and cyhalothrin did not inhibit the alcoholic fermentation at their proposed spraying concentration of 0.21, 0.10 and 0.10 g L−1, respectively, whereas chlorothalonil concentration above 0.03 g L−1 behaved significantly negative influence on both S. cerevisiae growth and alcoholic fermentation efficiency. When the chlorothalonil concentration was lower than 0.01 g L−1, the fermentation proceeded smoothly without any degradation of chlorothalonil. Considering the cumulative toxicity and adverse effect of chlorothalonil on fermentation, chlorothalonil hydrolytic dehalogenase (Chd) extracellularly expressed from the recombinant Bacillus subtilis WB800 was used to pretreat the chlorothalonil-contaminated grape slurry. After treatment by the Chd enzyme in an activity of 7.25 mU L−1 slurry for 60 min, the inhibition effect could be substantially eliminated even at an initial concentration of 0.10 g L−1 chlorothalonil. This study provides a potential approach for solving the conflict in fermentation industry with pesticides inhibition.

Photocatalyzed ozonation: effective degradation and mineralization of pesticide, chlorothalonil

The photocatalyzed and ozonated degradation of a widely used pesticide, chlorothalonil was studied using Ru loaded on titania as photocatalyst under visible light. The Ru/TiO2 photocatalysts with metal loadings 0, 0.25, 0.50, and 1 wt% on TiO2 were prepared by deposition–precipitation method and characterized by X-ray diffraction, UV-DRS, Brunauer–Emmett–Teller, transmission electron microscopy, SEM–EDX, FT-IR, and ICP analyses. Photocatalyzed ozonation with 1% Ru/TiO2 yielded 100% degradation and mineralization of chlorothalonil in 2 h under basic pH conditions. The extent of degradation of chlorothalonil pesticide and its mineralization were confirmed by GC–MS. For 10 mg/L of chlorothalonil, 0.1 g/L of catalyst was found to be the optimum for effective mineralization. Results show that photocatalyzed ozonation of chlorothalonil with Ru/TiO2 catalyst is a very practical means for its mineralization. The catalyst is fully recoverable and reusable multiple times with no loss of activity.

The isolation and characterization of the novel chlorothalonil-degrading strain Paracoccus sp. XF-3 and the cloning of the chd gene

Chlorothalonil (CTN) is one of the most widely used fungicides and is often detected in the environment. Here, we report the isolation and characterization of a novel CTN-degrading bacterial strain XF-3 from long-term CTN-contaminated sites and identify it as a strain of the Paracoccus sp. The isolate could utilise CTN as the sole source of carbon and energy for growth. The optimal pH and temperature for degradation by XF-3 were 7.0 and 30°C, respectively. The CTN degradation gene was cloned by PCR. Although the results of a BLAST sequence search indicated that this gene has a 99% similarity with chd (a gene encoding the CTN hydrolytic dehalogenase), its hydrolytic efficiency for CTN was slightly greater than the chd from strain CTN-3. This is the first report of this gene from the genus Paracoccus. Therefore, there is a practical significance and a potential value of the isolated novel strain, XF-3.

Degradation of chlorothalonil through a hydrolytic dehalogenase secreted from Bacillus subtilis WB800

To achieve the secretory expression of chlorothalonil hydrolytic dehalogenase (Chd), the chd gene was cloned into the vector pP43NMK under the control of the P43 promoter and the NprB signal peptide-encoding sequence and extracellularly expressed in the protease-deficient strain Bacillus subtilis WB800. The optimization of Chd production in submerged culture through Plackett-Burman and Box-Behnken designs enhanced the activity of Chd from 6.80 to 14.50 U l−1 and the protein expression amount from 1.93 μg ml−1 to 5.65 μg ml−1. The obtained Chd catalyzed a hydroxyl substitution at the 4-chlorine atom of chlorothalonil to form 4-hydroxy-trichloroisophthalonitrile, which is more soluble in water and easier to remove from the surface of vegetables. Six types of vegetables classified by the edible organ were selected for the chlorothalonil enzymatic degradation assay. After enzymatic reaction for 120 min, almost all of the 25 mg kg−1 chlorothalonil on cherry tomatoes was removed, approximately 82% of the 45 mg kg−1 chlorothalonil on lactuca sativa was removed, and approximately 40%–67% of the chlorothalonil on all other vegetables was removed. Moreover, the chlorothalonil eluted from the vegetables could be degraded to <1 mg l−1 after 3 h. The results of the present study demonstrated the potential of Chd to clean up chlorothalonil residue on the surfaces of vegetables.