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Pesticide residues in soil, especially multiple herbicide residues, cause a series of adverse effects on soil properties and microorganisms. In this work, the degradation of three herbicides and the effect on bacterial communities under combined pollution was investigated. The experimental results showed that the half-lives of acetochlor and prometryn significantly altered under combined exposure (5.02–11.17 d) as compared with those of individual exposure (4.70–6.87 d) in soil, suggesting that there was an antagonistic effect between the degradation of acetochlor and prometryn in soil. No remarkable variation in the degradation rate of atrazine with half-lives of 6.21–6.85 d was observed in different treatments, indicating that the degradation of atrazine was stable. 16S rRNA high-throughput sequencing results showed that the antagonistic effect of acetochlor and prometryn on the degradation rate under combined pollution was related to variation of the Sphingomonas and Nocardioide. Furthermore, the potential metabolic pathways of the three herbicides in soil were proposed and a new metabolite of acetochlor was preliminarily identified. The results of this work provide a guideline for the risk evaluation of combined pollution of the three herbicides with respect to their ecological effects in soil. [ABSTRACT FROM AUTHOR]

Chlorantraniliprole (CAP) is a new type of diamide insecticide that is mainly used to control lepidopteran pests. However, it has been proven to be hazardous to nontarget organisms, and the effects of its residues need to be monitored. In this study, five hybridoma cell lines were developed that produced anti-CAP monoclonal antibodies (mAbs), of which the mAb originating from the cell line 5C5B9 showed the highest sensitivity and was used to develop a gold nanoparticle-based lateral flow immunoassay (AuNP-LFIA) for CAP. The visible limit of detection of the AuNP-LFIA was 1.25 ng/mL, and the detection results were obtained in less than 10 min. The AuNP-LFIA showed no cross-reactivity for CAP analogs, except for tetraniliprole (50%) and cyclaniliprole (5%). In the detection of spiked and blind samples, the accuracy and reliability of the AuNP-LFIA were confirmed by a comparison with spiked concentrations and verified by ultra-performance liquid chromatography–tandem mass spectrometry. Thus, this study provides the core reagents for establishing CAP immunoassays and a AuNP-LFIA for the detection of residual CAP. [ABSTRACT FROM AUTHOR]

To clarify the residue formation of prothioconazole and its main metabolite in wheat plants, the uptake, translocation, and metabolism of prothioconazole in wheat roots and leaves were investigated by nutrient solution culture and the spraying method. The results showed that prothioconazole and its metabolites showed a trend of increasing and then decreasing in wheat plants under two treatment methods, and the concentration of prothioconazole and its metabolites was higher in the high-concentration group (5000 μg/mL) than in the low-concentration group (1000 μg/mL). The transferability from stem to leaf was stronger than that from root to stem. In the nutrient solution culture, prothioconazole and its metabolites were mainly enriched in wheat roots. The concentration of prothioconazole in wheat roots increases with the increase in prothioconazole concentration and was significantly higher than the prothioconazole concentration on stems and leaves. In wheat leaves in the spraying method, prothioconazole and its metabolites were conducted from leaves to stems and roots up to the nutrient solution. Prothioconazole-desthio was detectable in wheat nutrient solution, while prothioconazole was not detected. Analysis of actual samples of 9 wheat grains and 28 flours showed that the residues of prothioconazole and its metabolites met the maximum residue limit (0.1 mg/mL) set in China and by the Codex Alimentarius Commission. The results will provide a theoretical basis for the scientific use of prothioconazole and food security assurance. [ABSTRACT FROM AUTHOR]

The potential risk posed by the chiral triazole fungicide prothioconazole and its metabolite, prothioconazole-desthio to aquatic ecosystems has attracted attention. At present, the aquatic toxicity of prothioconazole is focused on aquatic animals, and the study of aquatic plants is limited. In this work, the acute toxicity of prothioconazole (PTZ) and its metabolite, prothioconazole-desthio (PTD), to the aquatic plant Lemna minor (L. minor) was evaluated at the enantiomer level. The effects of the prothioconazole and its metabolite enantiomer on the physiological and biochemical indices, including growth rate, photosynthetic pigment content, and antioxidant-defense-enzymes activity, of L. minor were measured to evaluate the potential risk. The results showed that prothioconazole and prothioconazole-desthio possessed obvious stereoselective toxicity to Lemna minor with an LC50 (7 days) of 0.76–5.63 mg/L. The toxicity order was S-PTD > Rac-PTD > S-PTZ > R-PTD > Rac-PTZ > R-PTZ. The S-PTZ, which had the highest toxicity, obviously inhibited the biosynthesis of photosynthetic pigments and the activity of antioxidant-defense enzymes (malondialdehyde, catalase and superoxide dismutase), leading to an increase in MDA content and oxidative damage. The results further confirmed that the metabolism of PTZ in aquatic ecosystems increased its exposure risk, providing data support and a theoretical basis for the risk assessment of PTZ. [ABSTRACT FROM AUTHOR]

Fungicides, including thiophanate-methyl, tebuconazole, pyraclostrobin, and difenoconazole, have been widely used as preservatives to control fungal diseases during pear storage. However, the metabolic capability of pear for exogenous compounds decreases at lower storage temperatures, leading to an increase in the risk of exposure to chemical preservatives. In this work, a sensitive and stable ultraperformance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) analytical method was established to investigate the dissipation dynamics and dietary intake risk of four chemical preservatives in pears under different conditions. The mean recoveries of the preservatives in pear samples ranged from 73.2% to 117.1%, with relative standard deviations of 0.5–7.2%. The dissipation half-lives (T1/2) of thiophanate-methyl, tebuconazole, pyraclostrobin, and difenoconazole in pears were 7.2–21.1 d and 31.6–173.3 d at storage temperatures of 25 °C and 4 °C, respectively. The results of dietary risk evaluation showed that the intake risk of preservatives in commercial pears was acceptable. However, some pears from commercial supermarkets still contained preservatives at amounts that exceeded the maximum residue limit (MRL) set by the Chinese government. This work provides a guideline for the risk evaluation of fruit preservatives on human health. [ABSTRACT FROM AUTHOR]