Dietary Intake Risk Assessment Research Articles

Residue dissipation and dietary intake risk assessment of thiophanate-methyl and its metabolite carbendazim in watercress under Chinese field conditions

ABSTRACT In this study,the QuEChERSand high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS)was applied to determine thiophanate-methyl and its metabolite carbendazim residue in watercress. The average recoveries of both analytes in watercress ranged from 96.2% to 102.9% with relative standard deviation (RSD) less than 8.2%. The limit of quantification (LOQ)of method for both analytes was 0.01 mg/kg. The field trials were carried out in 2018 to monitor the residues of thiophanate-methyl and its metabolite in six main cultivation areas inwatercressof China. Thiophanate-methylrapidly dissipated and transformed to carbendazim under watercress field conditions with half-lives less than 2.12 d.Carbendazim also rapidly dissipated with half-lives of 2.76 and 3.77d at two experiment sites. The terminal residue of thiophanate-methyl,carbendazim and total thiophanate-methyl were lower than 14.5 mg/kg, 5.26 mg/kg and 13.3 mg/kg, respectively. In order to ensure the safety, the acute and chronic dietary intake risks were evaluated. The ADI%of thiophanate-methyl, carbendazim and total thiophanate-methyl ranged from 21.1% to 84.9% and their%ARfDranged from 2.1% to 19.2%, which suggested that thiophanate-methyl and carbendazim has a low risk for Chinese populations caused by application of thiophanate-methyl.

Determination and Dietary Intake Risk Assessment of Pesticide Residues in Fritillariae Thunbergii Bulbs and Cultivated Soils.

Pesticide residues in traditional Chinese medicines pose a potential risk to human health. However, little is known about the characteristics of pesticide residues in the fritillariae thunbergii bulbs (FTB). This study aims to establish a method for the determination of pesticide multi-residues in FTB and then measured their residual levels in the FTB collected from nine cultivation regions. A modified QuEChERS method coupled with GC/UPLC was used to determine the residues of 24 pesticides in the FTB and soil samples. The recoveries of these pesticides at three concentrations were 72.17-112.48% in the FTB and 70.92-113.74% in the soil with RSD < 11.83%, and the LOD and LOQ ranged from 0.005-10 μg/kg and 0.011-22 μg/kg, respectively. A total of 13 pesticide residues were detected in the FTB samples with the residual levels of 0.0011-509.63 μg/kg, which were all below the referred MRLs in other Chinese herbs or food. Meanwhile, dietary intake risk assessment showed that the risk of pesticide residues in the FTB was acceptable to consumers. This study developed a method for the determination of pesticide multi-residues in the FTB and cultivated soil samples, and furthermore the dietary intake risk of pesticide residues in the FTB is safe. A modified QuEChERS method was established for the determination of 24 pesticides in the FTB with high sensitivity, accuracy, and precision.

Dissipation and residue of dimethomorph in potato plants produced and dietary intake risk assessment

ABSTRACT Late blight is a potentially devastating disease of potato. Dimethomorph has been widely used for preventing and controlling this disease. However, there is little information on dimethomorph residue in potato and the production soil. To address this issue, the present study developed a method for accurate analysis of dimethomorph using high-performance liquid chromatography. A linearity that had a determination coefficient of 0.9998 was established based on dimethomorph concentrations from 0.05 to 10.0 mg/L. The recovery rates ranged from 76.61% to 109.11%. The limit of detection and the limit of quantification were 0.02 mg/kg and 0.05 mg/kg, respectively. Potato production experiments were then carried out in three provinces of China, and dimethomorph was applied through a foliar spray. The established method was used for analysing the uptake, dissipation, and residues of dimethomorph in potato leaves and tubers and also in soils. Results showed that foliar spray of dimethomorph was translocated to tubers and generally within 2 days. The half-lives of dimethomorph in potato leaves, tubers, and soil ranged from 2.65 to 4.20, 1.79 to 3.71, and 4.62 to 9.0 days, respectively. The risk assessment of dietary exposure showed that all of the risk index values and the hazard quotient were less than 100%, indicating that foliar spray of dimethomorph on potato at 1.5 times the recommended minimum dosages poses little risk for consumption of the tubers in the three provinces of China.

Dissipation Dynamics and Dietary Risk Assessment of Kresoxim-Methyl Residue in Rice.

Kresoxim-methyl is a high-efficiency and broad-spectrum fungicide used for the control of rice fungal diseases; however, its residues after application potentially threaten human health. Investigations on the dissipation of kresoxim-methyl residue in rice field systems and dietary risk assessment of kresoxim-methyl in humans are limited. The present study employed the QuEChERS-GC-MS/MS method for residue analysis of kresoxim-methyl in rice plants, brown rice, and rice husks. The samples were extracted with acetonitrile and purified by PSA, C18 column, and GCB. The average recovery of the spiked target compounds in the three matrices was between 80.5% and 99.3%, and the RSD was between 2.1% and 7.1%. The accuracy and precision of the method is in accordance with the requirements of residue analysis methods. Dissipation dynamic testing of kresoxim-methyl in rice plants indicated a half-life within the range of 1.8–6.0 days, and a rapid dissipation rate was detected. Dietary intake risk assessment showed that the national estimated daily intake (NEDI) of kresoxim-methyl in various Chinese subpopulations was 0.022–0.054 μg/(kg bw·days), and the risk quotient (RQ) was 0.0000055–0.00014%. These findings indicate that the risk for chronic dietary intake of kresoxim-methyl in brown rice is relatively low. The present study provides information and theoretical basis for guiding the scientific use of kresoxim-methyl in rice fields and evaluating its dietary risk in brown rice.

Residues, dissipation kinetics, and dietary intake risk assessment of two fungicides in grape and soil

The residue behavior and dietary intake risk of two fungicides (dimethomorph and pyraclostrobin) in grape (Vitis vinifera L.) were investigated from field trials. A modified quick, easy, cheap, effective, rugged, and safe method for simultaneously determining dimethomorph and pyraclostrobin residues in grape and soil was established using high performance liquid chromatography–tandem mass spectrometry. The average recoveries of dimethomorph and pyraclostrobin in the grape and soil matrices varied from 76.88% to 97.05%, with relative standard deviations of 1.73%–10.38%. The degradation half-lives of dimethomorph and pyraclostrobin were 7.3–12.0 days and 3.6–7.0 days in grape and soil, respectively. The terminal residues of dimethomorph and pyraclostrobin in the two matrices were 0.05–0.87 mg/kg. For dietary exposure risk assessments, all of the hazard quotient and hazard quotient index values were below 100%, which indicated that the suspending agents of dimethomorph and pyraclostrobin were sprayed on grape at the recommended dosages with no significant potential risks for Chinese consumers. This study provides a reference for analytically evaluating residual degradation behavior and dietary intake risk of two fungicides under field conditions.

Residue behavior and dietary intake risk assessment of carbosulfan and its metabolites in cucumber

The residue behavior and dietary intake risks of carbosulfan and its metabolites in cucumbers were investigated. A quick and reliable method for determining carbosulfan and its metabolite residues in cucumbers was established using ultrahigh performance liquid chromatography–tandem mass spectrometry. The fortified recoveries ranged from 87.2% to 91.0% with relative standard deviations of 3.2%–8.1%. The dissipation results showed that carbosulfan was transformed into carbofuran and 3-hydroxy carbofuran in cucumbers. The half-life of carbosulfan was 1.5 days, and the half-life of carbofuran was 45 days. The final residues of carbosulfan varied from 0.245 to 0.005 mg/kg and carbofuran varied from 0.123 to 0.008 mg/kg. After a 5-day application period the residues of carbosulfan was 0.113 mg/kg that was below the maximum residue limit set by China (0.2 mg/kg), and the residues of carbofuran was 0.055 mg/kg that was higher than the maximum residue limit set by China (0.02 mg/kg). The risk assessment results indicated that the dietary intake risks of carbosulfan and carbofuran from cucumber consumption were safe for Chinese consumers, but pre-harvest intervals should be strictly recommended for 7 days at the recommended dose to ensure that food quality conforms to the MRL standard. This study provides a method and data for scientifically evaluating dietary intake risks of carbosulfan and its more toxic metabolites.

Residue behavior and dietary intake risk assessment of three fungicides in tomatoes (Lycopersicon esculentum Mill.) under greenhouse conditions

The residue behavior and dietary intake risk of three fungicides (pyrimethanil, iprodione, kresoxim-methyl) in tomatoes (Lycopersicon esculentum Mill.) grown in greenhouse were investigated. A simple, rapid analytical method for the quantification of fungicide residues in tomatoes was developed using gas chromatography coupled with mass spectrum detection (GC-MSD). The fortified recoveries were ranged from 87% to 103% with relative standard deviations (RSDs) varied from 4.7% to 12.1%. The results indicated that the dissipation rate of the studied fungicides in tomatoes followed first order kinetics with half lives in the range of 8.6–11.5 days. The final residues of all the fungicides in tomatoes were varied from 0.241 to 0.944 mg/kg. The results of dietary intake assessment indicated that the dietary intake of the three fungicides from tomatoes consumption for Chinese consumers were acceptable. This study would provide more understanding of residue behavior and dietary intake risk by these fungicides used under greenhouse conditions.

Residue behavior and dietary intake risk assessment of kresoxim-methyl and procymidone in strawberry under greenhouse conditions

Residue behavior and dietary intake risk assessment of kresoxim-methyl and procymidone in strawberry under greenhouse conditions