Insights into the Fate and Risk Identification of Cyantraniliprole and Lufenuron Based on Pak Choi (Brassica rapa L. subsp. chinensis)

Residue behavior and dietary risk assessment of six pesticides in pak choi using QuEChERS method coupled with UPLC-MS/MS

Dynamics and residues of difenoconazole and chlorothalonil in leafy vegetables grown in open-field and greenhouse

This study investigates the dissipation kinetics, terminal residues, and dietary risk assessment of metrafenone in tomatoes and cucumbers cultivated under greenhouse conditions in the Khubash governorate, Najran region, Saudi Arabia. Residue analysis was performed using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with acetonitrile-based extraction. The method demonstrated excellent linearity (R 2 = 0.9981 and 0.9946 for tomatoes and cucumbers, respectively), low limits of detection (LOD: 0.0002 mg kg-1 and 0.0003 mg kg-1, respectively), and limits of quantification (LOQ: 0.0025 mg kg-1 for both matrices). Recovery rates ranged from 93.6% to 98.1% and 92.7% to 99.7% for tomatoes and cucumbers, respectively, with relative standard deviations (RSDs) below 6%, ensuring method accuracy. Precision analysis demonstrated intra-day (RSDr) and inter-day (RSDR) repeatability below 16% for both matrices, confirming the method's repeatability. Matrix effects were minimal, with values of -6.71% and -4.15% for tomatoes and cucumbers, respectively, indicating negligible signal suppression. The dissipation followed first-order kinetics, with half-lives of 1.93-1.96 days and 1.61-1.67 days, respectively. The pre-harvest interval (PHI) was estimated at 1.18-1.56 days for tomatoes and 1.37-2.68 days for cucumbers. Terminal residues varied based on application rates and spray frequency, with some exceeding maximum residue limits (MRLs) at early intervals before declining to safe levels. Chronic dietary risk assessment confirmed that the chronic hazard quotient (HQc) values remained significantly below the safety threshold of 100%, indicating no significant health risks. These findings provide essential data for determining appropriate PHIs and ensuring food safety compliance in commercial crop production.

Rosa roxburghii (R. roxburghii) is edible and medicinal fruit rich in vitamin C. Residues and potentially ecological risks of chlorantraniliprole (CAP) in the R. roxburghii orchard have aroused concern considering its extensive use for controlling oriental fruit moth, aphid, and whitefly of R. roxburghii. In this study, an effective UPLC–MS/MS method was developed for quantitation of CAP in R. roxburghii and soil using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) dispersive solid-phase extraction with average recoveries of 73.89–96.63% and a relative standard deviation of <15%. Dissipation dynamics and terminal residue trials under the field conditions in 2021 and 2022 showed that half-lives of CAP in R. roxburghii (2.64–2.70 days) were shorter than those in soil (3.58–3.80 days), and its terminal residues in R. roxburghii and soil were 0.034–0.818 mg kg-1 and 0.003–0.015 mg kg-1, respectively. Long-term dietary and soil ecological risk assessments indicated that the risk quotient was significantly less than 100%, meaning that the use of CAP on R. roxburghii at the recommended dosage was safe to consumers and soil ecology system, and that maximum residue limits (MRLs) and safe pre-harvest intervals of CAP in R. roxburghii were recommended as 0.7 mg kg-1 and 14 days, respectively. Removal experiments of CAP residues from R. roxburghii using simple household processing approaches exhibit that 2% baking soda water had the highest removal efficiency (56.04–60.33%). This study provides the basic data for establishing MRL, the safe and rational use of CAP in R. roxburghii production as well as the household decontamination prior to consumption of R. roxburghii fruits.

Oxadixyl and cymoxanil are widely used for controlling downy mildew in cucumber; however, there are few systematic studies on monitoring residue levels of these two pesticides in cucumber under greenhouse and open field conditions. In this study, a simplified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied to analyze target compounds in cucumber. The average recoveries of oxadixyl and cymoxanil in cucumber ranged from 96% to 102%, with relative standard deviations (RSDs) of 1.8%–4.0%. The limits of quantification (LOQs) for two pesticides were both 0.01 mg/kg. The dissipation of oxadixyl was in accordance with a first-order kinetics equation, with half-lives ranging from 1.8 to 3.1 days. At the pre-harvest interval (PHI) of 3 or 5 days, the residue levels of oxadixyl in cucumber under open field conditions were higher than those under greenhouse conditions. Compared to oxadixyl, the cymoxanil degraded quickly, and its residues were below LOQ on the 3rd or 5th day after the last application. The terminal residues of oxadixyl and cymoxanil in the cucumber were both lower than the maximum residue limits (MRLs) in China. The risk quotient (RQ) used for dietary risk assessment was 1.8%–3.5% and 0.26%–0.51% for oxadixyl and cymoxanil, respectively. The results showed that the risks of these two pesticides used on cucumber at the experimental dosages are comparably acceptable for Chinese consumers of different gender and age groups. This study provides a reference data to use oxadixyl and cymoxanil scientifically and rationally.

Carbendazim and epoxiconazole are widely applied to control anthracnose and sand bark fungal diseases in citrus. The residues of these two fungicides in citrus and their potential risk to consumers have generated much public concern. We therefore sought to investigate the dissipation, residue, and dietary risk assessment of carbendazim and epoxiconazole in citrus. The dissipation kinetics and residue levels of carbendazim and epoxiconazole in citrus under field conditions were measured using dispersive solid-phase extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry. The citrus samples were extracted with acetonitrile and purified by primary secondary amine sorbent. The mean recoveries of carbendazim and epoxiconazole ranged from 86.2 to 105.6% and relative standard deviations were ≤9.8%. The half-lives of carbendazim and epoxiconazole in whole citrus ranged from 2.0 to 18.0 days. Hazard quotient (HQ) and risk quotient (RQ) models were applied to whole citrus for dietary exposure risk assessment based on the terminal residue test. Hazard quotients ranged from 0.066 to 0.134% and RQs from 18.48 to 82.12%. Carbendazim and epoxiconazole in citrus degraded rapidly following first-order kinetics models. The dietary risk of exposure to both carbendazim and epoxiconazole through citrus, based on HQ and RQ, was acceptable for human consumption. This study indicates scientifically validated maximum residue limits in citrus, which are currently lacking for epoxiconazole in China. © 2021 Society of Chemical Industry.

Dimethachlon, a dicarboximide fungicide, has gained widespread usage in Asian countries. While considered a low-toxicity fungicide, concerns regarding potential health effects, such as nephrotoxicity, have emerged. To date, neither China nor other countries have established maximum residue limit (MRL) for dimethachlon on grapes, and exposure risk assessment of dimethachlon is lacking. Here, we developed a QuEChERS method coupled with gas chromatography-mass spectrometry (GC-MS) to investigate the dissipation rates and terminal residues of dimethachlon in grapes, along with an assessment of dietary risk to consumers. Our results indicated that the average recoveries of dimethachlon in grapes ranged from 74 to 76%. The limit of quantification (LOQ) was 0.050mg/kg. After undergoing 112days of storage at -18°C, the dissipation rate of dimethachlon in grapes was found to be less than 30%, suggesting a state of stable storage. In the context of good agricultural practice (GAP) guidelines, the half-lives of dimethachlon in grapes were 14.3-18.1days, which is notably longer compared to the reported values for other crops. The terminal residues of dimethachlon in grapes at 14 and 21days were found to be < 0.05-0.53mg/kg and < 0.05-0.29mg/kg, respectively. Regarding the dietary risk assessment, the calculated risk quotient (RQ) value was significantly below 100%, indicating a negligible chronic risk of dimethachlon in grapes at the recommended dosage. This study provides an important reference for the analysis of dimethachlon and offers valuable empirical data to support the establishment of MRL.

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established to investigate the residues of emamectin benzoate (EB), imidacloprid (IMI) and five IMI metabolites (IMI-olefin, IMI-urea, IMI-guanidine, 5-OH and 6-CNA) in cabbage. The average recoveries of the seven compounds in cabbage were 80%-102%, with relative standard deviations (RSDs) <8.0%. The limit of quantification (LOQ) for each compound was 0.01 mg kg -1 . Standardized residue tests were carried out in 12 areas of China under Good Agricultural Practice (GAP) conditions. A 10% EB-IMI microcapsule suspension was applied once with the high recommended dosage (18 g a.i. ha-1 ) on cabbage. The residues of EB (<0.01 mg kg-1 ), IMI (<0.016 mg kg-1 ) and the sum of IMI and its metabolites (<0.068 mg kg-1 ) in cabbage on the recommended preharvest interval (PHI) (7 d) were lower than the maximum residue limits (MRLs) in China. Based on residual data from fields, toxicology data, and Chinese dietary patterns, dietary risk assessments were conducted. Both the chronic risk quotients (25.2%-73.1%) and acute risk quotients (0.43%-1.57%) of EB and IMI were below 100%, indicating no unacceptable public health risk for different populations. This study provides guidance on the rational application of these insecticides in cabbage.

The chemical insecticide flonicamid is widely used to control aphids on crops. Differences among crops make the universality of detection methods a particularly important consideration. The aim of this study was to establish a universal, sensitive, accurate and efficient method for the determination of flonicamid residues in peach, cucumber, cabbage and cotton. QuEChERS pretreatment was combined with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A satisfactory recovery rate of 84.3-99.3% was achieved at three spiking levels, and the relative standard deviation (RSD) was 0.41-5.95%. The limit of quantification (LOQ) of flonicamid in the four matrices was 0.01 mg/kg. The residue and dissipation kinetics of flonicamid in four types of crops in various locations were determined by using the optimized method. The results showed that flonicamid had a high dissipation rate in the four different types of crops and a half-life in the different matrices and locations of 2.28-9.74 days. The terminal residue of flonicamid was lower than the maximum residue limit (MRL). The risk quotient (RQ) of flonicamid was 4.4%, which is significantly lower than 100%. This result shows that the dietary risk presented by using flonicamid at the maximum recommended dose is low and acceptable. The comprehensive long-term dietary risk assessment of flonicamid performed in this study provides a reference for the protection of consumer health and safe insecticide use.

The degradation behaviour, residue distribution, and dietary risk assessment of malathion on vegetables and fruits in China by GC-FPD

Dissipation kinetics, pre-harvest residue limits, and dietary risk assessment of the systemic fungicide metalaxyl in Swiss chard grown under greenhouse conditions

In the present work, the dissipation kinetics and final residue levels of thifluzamide in the maize field ecosystem were investigated. Using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction combined with liquid chromatography-tandem mass spectrometric detection (LC-MS/MS), a rapid, sensitive, efficient, and reliable method for extraction and quantitative analysis of thifluzamide residues in maize grain, maize plant, and soil was developed. Satisfactory recoveries of 78.7-97.0% were achieved with relative standard deviations (RSDs) in the range of 1.6 to 8.2%. The limits of detection (LODs) and the limit of quantification (LOQ) were 0.002-0.005 and 0.010mgkg-1, respectively. The dissipation kinetics of thifluzamide in maize plant was well fitted by the first-order kinetic model with short half-lives of 0.19-0.22days, while thifluzamide degraded slowly in soil with half-lives of 4.56-15.85days. The final residues in maize grain, maize plant, and soil samples collected at the milk stage and the physiological maturity stage were no more than 0.010, 0.807, and 0.278mgkg-1, respectively. Given that no maximum residue limit (MRL) for thifluzamide in maize has been established, the safety of this fungicide application was estimated by a dietary risk assessment. The hazardquotient was 0.03%, which was substantially less than 1, indicating that the long-termrisk induced by the thifluzamide application on maize at the recommended dose is negligible. These results help governments to develop regulations for the safe use of thifluzamide.

Dissipation rates and residue levels of diflubenzuron and difenoconazole on peaches and dietary risk assessment

Neonicotinoid pesticides were detected, and dietary risk assessment was performed in commercially available vegetables and fruits in North China from 2021 to 2024. A modified QuEChERs (quick, easy, cheap, effective, rugged, and safe) pretreatment method combined with UPLC-MS/MS (ultra-high-performance liquid chromatography triple quadrupole mass spectrometry) was applied to the detection. The validation and evaluation of the method were performed in terms of matrix effect, recovery (75.5 ~ 104.6%), limit of quantification (2.08 ~ 7.53μg/kg), and linear correlation coefficient (0.9913 ~ 0.9995). Twelve neonicotinoid pesticides were detected in 128 samples. Forty-three samples were positive for neonicotinoid pesticides, with a detection rate of 33.6%. Multicomponent pesticide residues were detected in 12 samples, accounting for 9.4%. Neonicotinoid pesticides exceeded the corresponding MRLs (maximum residue limits) in 10 samples, accounting for 7.8%. Thiamethoxam was the most detected neonicotinoid pesticide, with positive detections in 18 samples. Clothianidin from ginger had the highest Hazard index. The effects of neonicotinoid pesticide residues were within acceptable limits in both adults and minors. MRLs and ADI (acceptable daily intake) limits for many neonicotinoid pesticides in food were not well established in some countries and regions. Residues of neonicotinoid pesticides in commercially available agricultural products require adequate attention and further surveillance.

Validation of a Brief Dietary Assessment to Guide Counseling for Cardiovascular Disease Risk Reduction in an Underserved Population