To understand the residues and dissipation dynamics of pyrethroid insecticides in Prunus persica L. fruits from the Xiaogan City and assess their dietary intake risk.
Prunus persica L. fruit samples were homogenized, and the target compounds were extracted using acetonitrile as the extraction solvent. The extracts were purified using a combination of primary secondary amine and Florisil. Chromatographic separation was performed on an RTX-5 capillary column (30 m×0.25 mm, 0.25 μm), and detection was carried out using an electron capture detector. Quantification was achieved by the external standard method to determine the residue levels in fruits at 0–23 days after application under different dilution treatments.
Method validation results showed that the 4 kinds of pyrethroid insecticides exhibited good linearity within the concentration range of 0.01–1.00 mg/kg (r2≥0.9942). The average recoveries ranged from 78.85% to 97.62%, with relative standard deviations between 2.12% and 6.85%. The limits of detection and limits of quantitation were 0.001 mg/kg and 0.003 mg/kg, respectively, indicating that the method possesses satisfactory sensitivity and accuracy. Field trial results demonstrated that the residue levels of the 4 kinds of insecticides in peach fruits decreased significantly over time, following first-order kinetic dissipation patterns, with half-lives ranging from 2.60 to 12.95 days. The initial residue concentration increased significantly with higher application concentrations. Residues decreased to 20%–40% of the initial values by day 5 after application, and most treatments showed residue levels below 0.50 mg/kg at 16–23 days, meeting the pre-harvest interval requirements for food safety. Dietary risk assessment indicated that the national estimated daily intakes of the 4 kinds of pesticides under different dilution treatments were substantially lower than their corresponding acceptable daily intakes. The risk quotients ranged from 0.002 to 0.103 (all<1).
Under regular application concentrations and harvest interval conditions, the health risk to consumers is relatively low. Based on the dissipation kinetic data, it is recommended that for the rapidly degrading fenpropathrin and lambda-cyhalothrin, the pre-harvest interval should be no less than 16 days; for the more persistent beta-cypermethrin and deltamethrin, the interval should be extended to 23 days. This study provides important scientific evidence for the safe application of pyrethroid insecticides in Prunus persica L. orchards in the Xiaogan City and offers technical support for their scientific use and management.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |