Residue and chronic dietary exposure risk assessment of spinetoram and its metabolites in rice

To clarify the potential chronic dietary exposure risk associated with the use of spinetoram on rice, a supervised field trial was conducted across twelve sites over a year to investigate the final residues of spinetoram and its metabolites in brown rice and rice husk. The long-term dietary risks were evaluated based on dietary consumption data of different population groups. In this study, high-performance liquid chromatography-tandem mass spectrometry was used to detect spinetoram and its metabolites in rice samples, with the average recovery rates of 87%-114% and relative standard deviations of 1.0%-13%. The storage stability of the target pesticides was determined to be at least three months. The degradation dynamic tests conducted in Heilongjiang, Jiangsu, Guangxi, and Hainan showed that the half-life of spinetoram in rice husk ranged from 3.83 to 6.66 days. The final residue test results across twelve sites indicated that the residues of spinetoram in brown rice and rice were < 0.010 mg/kg and < 0.010-0.045 mg/kg, respectively. The long-term dietary risk assessment for different population groups revealed that the national estimated daily intake (NEDI) of spinetoram was 0.0029-0.0077 mg/kg bw, and the contribution (RQc) of the residues of spinetoram in rice and its products to the total risk quotient (RQ) ranging from 0.16% to 0.30%. It suggests that the long-term dietary risk to different population groups through the consumption of rice and its products is relatively low, but the amplification of the exposure risk due to dietary diversification needs to be considered. This study provides important data support for the rational use of spinetoram and for the food safety assurance.