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[学术文献 ] Dissipation dynamics of methomyl, phoxim, and pymetrozine during mulberry (Morus alba L.) leaves harvest, tea processing and brewing 进入全文
Food Chemistry 期刊
Mulberry leaf tea is known for its health benefits; however, concerns remain about pesticide residues during harvest, processing, and brewing. The dissipation dynamics of methomyl, phoxim, and pymetrozine were systematically investigated in this study. In fresh leaves, their half-lives ranged from 1.1 to 2.3 days, with dissipation rates of 64.6–87.8 % within three days. During tea processing, dissipation rates in black and green tea ranged from 46.3 % to 78.9 %, influenced by the initial pesticide levels and processing conditions. The dissipation of pesticides was significantly influenced by drying and spreading/withering. During brewing, pesticide leaching was closely related to water solubility, with 33.8–76.9 % of methomyl and pymetrozine transferring to the infusion, compared to just 0.32–3.2 % for the less water-soluble phoxim. Overall, at least 85 % of the pesticides dissipated across harvest, processing, and brewing, suggesting negligible health risks based on risk quotient assessment.
[学术文献 ] Residue analysis and risk assessment of cyflumetofen and its three metabolites from fresh tea leaf to tea infusion through purification with new nano adsorbents and determination by ultra-performance liquid chromatography-tandem mass spectrometry 进入全文
Microchemical Journal 期刊
A simultaneous residue analysis method for cyflumetofen and its three metabolites (B-1, B-3, and AB-1) in fresh tea leaves, green tea, black tea, green tea infusion and black tea infusion was developed. Samples were extracted with acetonitrile containing 1 % of formic acid, followed by purification using multi-walled carbon nanotubes (MWCNT) and nano-ZrO2 absorbents in conjunction with low-temperature clean (LTC). The samples were then analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The calibration curves for cyflumetofen and its metabolites, ranging from 0.005 to 2.0 mg/L (excluding B-1, which is from 0.01 to 2.0 mg/L), demonstrated satisfactory correlation coefficients (R2) of at least 0.9931 across various tea matrix-matched conditions. The average recoveries for cyflumetofen and its three metabolites in different tea matrixes ranged from 71.9 % to 116.9 %, with relative standard deviations (RSDs) below 15.1 %. The limits of quantification (LOQs) were set at 0.005 mg/kg for fresh tea leaves, black tea, and green tea, and 0.5 µg/L for black and green tea infusion. For B-1, the LOQs were set at 0.01 mg/kg for black and green tea, and 1.0 µg/L for black and green tea infusion. After applying a 20 % cyflumetofen suspension concentrate to a tea plant field, real fresh tea leaf samples were found to contain cyflumetofen and its three metabolites B-1, B-3, and AB-1. The half-life (t1/2) of cyflumetofen in fresh tea leaves was found to be 1.18 days. During the tea processing, various processing steps had distinct impacts on compound residues, especially under high-temperature conditions. The total processing factors (TPFs) for cyflumetofen in green tea and black tea ranged from 0.75 to 1.16 and 1.31 to 2.78, respectively. The leaching rates (LRs) of cyflumetofen from tea to tea infusion were 2.6 % for green tea and 2.4 % for black tea. Based on risk assessment, the total dietary risk quotients for both cyflumetofen and B-1 were significantly below 100 %.
[学术文献 ] Neonicotinoid Insecticides and Their Characteristic Metabolites may Induce High Fasting Blood Glucose and Obesity in Human 进入全文
Exposure and Health 期刊
In this study, the concentrations of six NEOs and their five metabolites were measured in the blood samples collected from the normal (n = 130) and obesity (n = 130) cohorts in South China. An evaluation was undertaken to examine the associations between the levels of target analytes and either fasting blood glucose (FBG) or the condition of being overweight. Results showed that the NEOs and their metabolites were frequently detected (63–100%) in both cohorts, with median levels of 0.01–4.32 ng/mL. Discernible gender-related disparities were noted within the blood samples, manifesting as elevated concentrations of the majority of NEOs and their metabolites in females compared to males. In addition, there were positive correlations between the concentrations of IMIeq (imidacloprid equivalent, calculated using the relative potency factors of NEOs and their metabolites) and 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF, a metabolite of dinotefuran) with FBG levels (3.28 ng/mL vs. 4.32 ng/mL for UF, and 34.6 ng/mL vs. 40.6 ng/mL for IMIeq). Moreover, significant associations were found between UF [odds ratio 1.78, 95% confidence interval (CI) 0.86–4.66, p < 0.01] and IMIeq (odds ratio 1.66, 95% CI 0.94–3.56, p < 0.01) concentrations and being overweight. Our findings indicated that human exposure to NEOs and their metabolites may induce high FBG and obesity. This study documented the profile of NEOs and their metabolites in the blood samples from the normal and obesity cohorts in South China for the first time.
[科技图书 ] Nano-Insecticide: Today and Future Perspectives 进入全文
SpringerLink 网站
本书涵盖了广泛的主题，包括用于杀虫剂输送和释放的纳米颗粒，用于害虫监测和检测的纳米结构材料，用于害虫特异性靶向的纳米生物技术方法、环境影响、安全考虑等。还介绍了来自各种农业和城市环境的案例研究和实际应用。每一章都由各自领域的顶级专家撰写，确保内容反映了纳米技术在害虫控制方面的最新进展和观点。本书为研究人员、从业者、政策制定者和对纳米技术和害虫管理交叉感兴趣的学生提供了宝贵的资源。通过全面概述该领域的当前最新技术和未来方向，纳米杀虫剂旨在促进这一关键领域的进一步研究和创新，提高对新型害虫管理策略的理解和应用。
[学术文献 ] Metabolic mechanism, responses, and functions of genes HDH1, HDH3, and GST1 of tea ( Camellia sinensis L.) to the insecticide thiamethoxam 进入全文
Journal of Hazardous Materials 期刊
Misuse of insecticides such as thiamethoxam (TMX) not only affects the quality of tea but also leaves residues in tea. Therefore, exploring the metabolic mechanisms of TMX in tea plants can evaluate effects of pesticides on the environment and human health. Here, effects of TMX on tea plants were studied. Malondialdehyde (MDA) content reached a maximum of 12.59 nmol/g fresh weight (FW) on 1st d under X (the recommended dose: 0.015 kg a.i./ha) of TMX. Under 2 X (0.03 kg a.i./ha), the catalase, glutathione S-transferase and superoxide dismutase activity were increased by 45.0 %, 55.5 %, and 49.7 % at 7 d respectively. Metabolomic and transcriptomic analyses revealed that TMX significantly affected amino acid metabolism, flavonoid biosynthesis and glutathione metabolism, and induced the expression of 3-hydroxyisobutyric acid dehydrogenase genes (CsHDH1 and CsHDH3) and glutathione S-transferase gene (CsGST1). The three genes were transiently expressed in Nicotiana benthamiana for the first time to verify the function of TMX degradation, with the degradation rate of 59.2 %-85.3 % at X. This study elucidated the response of tea plants to abiotic stress on the molecular-scale perspective, and the molecular approaches could serve as a model for the study on pesticide metabolism in plants.
[会议论文 ] Quantifying Sources of Variability in Neonicotinoid Residue Data for Assessing Risks to Pollinators 进入全文
Proceedings Paper
Using available field residue data for the neonicotinoid class of insecticides, we conducted an analysis of variability in residue data to address these and other study design elements. Comparisons of the magnitude of residues and variability are made across neonicotinoid chemicals (imidacloprid, clothianidin, thiamethoxam and dinotefuran) as well as the variability associated with intra- and inter-crop group comparisons and regional and soil texture gradients. Additionally, this analysis includes consideration of bee-relevant toxic metabolites for imidacloprid and thiamethoxam. Results of these analyses of neonicotinoid residue data are presented in the context of optimizing field residue study designs for assessing pesticide risks to bees.
