Dissipation behavior and risk assessment of tolfenpyrad from tea bushes to consuming

Combination of biotransformation and metabolomics reveals tolfenpyrad-induced hepatocytotoxicity

Tolfenpyrad (TFP) is an extensively used pesticide that inevitably leads to human exposure to both TFP and its transformation product residues. However, the biotransformation of TFP in humans has not been elucidated, and the toxicity of TFP along with its biotransformation products remains largely unknown. In this study, the biotransformation process of TFP was investigated using human liver microsomes and human hepatic cells. Endogenous metabolic changes in the cells were studied to investigate the hepatocytotoxicity of TFP at environmentally relevant concentrations. Fourteen phase I biotransformation products and four phase II TFP products were characterized, among which twelve products were identified for the first time. The oxidative product tolfenpyrad-benzoic acid (PT-CA) was particularly abundant and stable. Further hepatotoxicity assessments and metabolic studies demonstrated comparable metabolic profiles for TFP and PT-CA in HepG2 cells, with both significantly disrupting purine and glutathione metabolism. These processes are closely associated with oxidative stress, mitochondrial damage, and cell death. Our results provide novel perspectives on the biotransformation, metabolism, and hepatotoxicity of TFP, thereby highlighting the non-negligible toxicity of its crucial biotransformation product PT-CA in environmental risk assessments.

Toxic effects of the insecticide tolfenpyrad on zebrafish embryos: Cardiac toxicity and mitochondrial damage

Tolfenpyrad, a highly effective and broad-spectrum insecticide and acaricide extensively utilized in agriculture, presents a potential hazard to nontarget organisms. This study was designed to explore the toxic mechanisms of tolfenpyrad on zebrafish embryos. Between 24 and 96 h after exposure of the fertilized embryos to tolfenpyrad at concentrations ranging from 0.001 to 0.016 mg/L (96 h-LC50 = 0.017 mg/L), lethal effects were apparent, accompanied with notable anomalies including pericardial edema, increased pericardial area, diminished heart rate, and an elongated distance between the venous sinus and the arterial bulb. Tolfenpyrad elicited noteworthy alterations in the expression of genes pertinent to cardiac development and apoptosis, with the most pronounced changes observed in the cardiac development-related genes of bone morphogenetic protein 2b (bmp2b) and p53 upregulated modulator of apoptosis (puma). The findings underscore that tolfenpyrad induces severe cardiac toxicity and mitochondrial damage in zebrafish embryos. This data is imperative for a comprehensive assessment of tolfenpyrad risks to aquatic ecosystems, particularly considering the limited knowledge regarding its detrimental impact on aquatic vertebrates.

Insight into the uptake, translocation, metabolism, dissipation and risk assessment of tolfenpyrad in romaine and edible amaranth grown in hydroponic conditions

Tolfenpyrad is an alternative to highly water-soluble and ecotoxic insecticides that is widely used in China. It is absorbed and accumulates in vegetables, leading to potential public-health hazards. A systematic study of the fate of tolfenpyrad is necessary for proper application and food safety. Herein, we report on the uptake, translocation, metabolism, dissipation, and dietary risks of tolfenpyrad in hydroponic romaine and amaranth plants. Roots easily absorbed and accumulated tolfenpyrad, although transport was moderate in both vegetables. Basipetal translocation of tolfenpyrad occurred in romaine but not in edible amaranth, owing to differences in specific transport behaviour in each case. Six metabolites and three pathways were proposed. Tolfenpyrad affected antioxidant enzyme activities in different parts of the two vegetables. Tolfenpyrad dissipation proceeded swiftly, entailing an acceptable risk to humans. Our results provide information on the distribution and transport of tolfenpyrad, as well as on the safety in using it on vegetables.

Uptake and translocation of organic pollutants in Camellia sinensis (L.): a review

Camellia sinensis (L.) is a perennial evergreen woody plant with the potential for environmental pollution due to its unique growth environment and extended growth cycle. Pollution sources and pathways for tea plants encompass various factors, including atmospheric deposition, agricultural inputs of chemical fertilizers and pesticide, uptake from soil, and sewage irrigation. During the cultivation phase, Camellia sinensis (L.) can absorb organic pollutants through its roots and leaves. This review provides an overview of the uptake and translocation mechanisms involving the absorption of polycyclic aromatic hydrocarbons (PAHs), pesticides, anthraquinone (AQ), perchlorate, and other organic pollutants by tea plant roots. Additionally, we summarize how fresh tea leaves can be impacted by spraying pesticide and atmospheric sedimentation. In conclusion, this review highlights current research progress in understanding the pollution risks associated with Camellia sinensis (L.) and its products, emphasizing the need for further investigation and providing insights into potential future directions for research in this field.

The bitter side of teas: Pesticide residues and their impact on human health

Tea (Camellia sinensis) is one of the most widely consumed non-alcoholic beverages globally, known for its rich composition of bioactive compounds that offer various health benefits to humans. However, the cultivation of tea plants often faces challenges due to their high vulnerability to pests and diseases, resulting in the heavy use of pesticides. Consequently, pesticide residues can be transferred to tea leaves, compromising their quality and safety and potentially posing risks to human health, including hormonal and reproductive disorders and cancer development. In light of these concerns, this review aims to: (I) present the maximum limits of pesticide residues established by different international regulatory agencies; (II) explore the characteristics of pesticides commonly employed in tea cultivation, encompassing aspects such as digestion, bioaccessibility, and the behavior of pesticide transfer; and (III) discuss the effectiveness of detection and removal methods for pesticides, the impacts of pesticides on both tea plants and human health and investigate emerging alternatives to replace these substances. By addressing these critical aspects, this review provides valuable insights into the management of pesticide residues in tea production, with the goal of ensuring the production of safe, high-quality tea while minimizing adverse effects on human health.

Phenylboronic acid-functionalized magnetic metal-organic framework nanoparticles for magnetic solid phase extraction of five benzoylurea insecticides

This research involves the construction of a phenylboronic acid-functionalized magnetic UiO-66 metal-organic framework (MOF) nanoparticle (CPBA@UiO-66@Fe₃O₄). Its design is primarily for the magnetic solid phase extraction (MSPE) of benzoylurea insecticides. An organic ligand, 2-amino terephthalic acid (2-ATPA), facilitated the introduction of amino groups while keeping the original crystal structure of UiO-66 intact. The constructed UiO-66 MOF showcases a porous structure and extensive surface area, thereby providing an optimal platform for further functionalization. The employment of 4-carboxylphenylboronic acid as a modifier notably amplified the extraction efficiency for benzoylureas. This improvement was due to the formation of B-N coordination and other secondary interactions. By integrating this with high-performance liquid chromatography (HPLC), we established a quantitative analytical method for benzoylurea insecticides. This method achieved a wide linear range (2.5-500 μg L^-1 or 5-500 μg L^-1), satisfactory recoveries (83.3-95.1%), and acceptable limits of detection (LODs: 0.3-1.0 μg L^-1). The developed method proved successful when applied to six tea infusion samples, representing China's six major tea categories. Semi-fermented and light-fermented tea samples demonstrated relatively higher spiking recoveries.

Dissipation, Metabolism, Accumulation, Processing and Risk Assessment of Fluopyram and Trifloxystrobin in Cucumbers and Cowpeas from Cultivation to Consumption

Fluopyram and trifloxystrobin are widely used for controlling various plant diseases in cucumbers and cowpeas. However, data on residue behaviors in plant cultivation and food processing are currently lacking. Our results showed that cowpeas had higher fluopyram and trifloxystrobin residues (16.48-247.65 μg/kg) than cucumbers (877.37-3576.15 μg/kg). Moreover, fluopyram and trifloxystrobin dissipated faster in cucumbers (half-life range, 2.60-10.66 d) than in cowpeas (10.83-22.36 d). Fluopyram and trifloxystrobin were the main compounds found in field samples, and their metabolites, fluopyram benzamide and trifloxystrobin acid, fluctuated at low residue levels (≤76.17 μg/kg). Repeated spraying resulted in the accumulation of fluopyram, trifloxystrobin, fluopyram benzamide and trifloxystrobin acid in cucumbers and cowpeas. Peeling, washing, stir-frying, boiling and pickling were able to partially or substantially remove fluopyram and trifloxystrobin residues from raw cucumbers and cowpeas (processing factor range, 0.12-0.97); on the contrary, trifloxystrobin acid residues appeared to be concentrated in pickled cucumbers and cowpeas (processing factor range, 1.35-5.41). Chronic and acute risk assessments suggest that the levels of fluopyram and trifloxystrobin in cucumbers and cowpeas were within a safe range based on the field residue data of the present study. The potential hazards of fluopyram and trifloxystrobin should be continuously assessed for their high residue concentrations and potential accumulation effects.

Computer-Aided Prediction, Synthesis, and Characterization of Magnetic Molecularly Imprinted Polymers for the Extraction and Determination of Tolfenpyrad in Lettuce

Tolfenpyrad, a pyrazolamide insecticide, can be effectively used against pests resistant to carbamate and organophosphate insecticides. In this study, a molecular imprinted polymer using tolfenpyrad as a template molecule was synthesized. The type of functional monomer and the ratio of functional monomer to template were predicted by density function theory. Magnetic molecularly imprinted polymers (MMIPs) were synthesized using 2-vinylpyridine as a functional monomer in the presence of ethylene magnetite nanoparticles at a monomer/tolfenpyrad ratio of 7:1. The successful synthesis of MMIPs is confirmed by the results of the characterization analysis by scanning electron microscopy, nitrogen adsorption-desorption isotherms, Fourier transform infrared spectroscopy, X-ray diffractometer, thermogravimetric analyzer, and vibrational sample magnetometers. A pseudo-second-order kinetic model fit the adsorption of tolfenpyrad, and the kinetic data are in good agreement with the Freundlich isothermal model. The adsorption capacity of the polymer to the target analyte was 7.20 mg/g, indicating an excellent selective extraction capability. In addition, the adsorption capacity of the MMIPs is not significantly lost after several reuses. The MMIPs showed great analytical performance in tolfenpyrad-spiked lettuce samples, with acceptable accuracy (intra- and inter-day recoveries of 90.5-98.8%) and precision (intra- and inter-day relative standard deviations of 1.4-5.2%).

Multi-residue analysis, dissipation behavior, and final residues of four insecticides in supervised eggplant field

In this study, the residues of four insecticides, spirotetramat, flonicamid, thiamethoxam, and tolfenpyrad, and their metabolites, including spirotetramat-enol, spirotetramat-mono-hydroxy, spirotetramat-keto-hydroxy, spirotetramat-enol-glucoside, 4-trifluoromethylnicotinamide, 4-trifluoromethylnicotinic acid, N-(4-trifluoromethylnicotinoyl) glycine, and clothianidin, were assessed using a single analysis method. The samples were extracted by acetonitrile, then purified by dispersive solid phase extraction and quantified using high performance liquid chromatography tandem mass spectrometry. The average recovery rate of 12 target compounds was 73.5-103.7%, the relative standard deviation was 1.1-18.3%, and the limit of quantification was 0.01-0.05 mg/kg. The results showed good linearity (R² >0.99), meeting the requirements of the pesticide residue analysis. The dissipation half-lives of the four insecticides in eggplant were 3.4-14.5 days. After the last applications at 7 and 10 days, the final residues of the four insecticides in eggplant were <0.01-0.21, 0.085-0.26, <0.05-0.078, and <0.01-0.21 mg/kg, respectively. The dissipation and final residue results could provide a theoretical basis for the rational application of four insecticides in eggplant fields.HighlightsHPLC-MS/MS for simultaneous determination of four insecticides and their metabolites in eggplant fields.The dissipation dynamics and final residue of the target compounds in field eggplant were studied.Guidance for the safe use of four insecticides on eggplant.