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.