Residue and distribution of fosthiazate in cucumber (Cucumis sativus L.) and dietary intake risk assessment for various populations

Abstract

ABSTRACT The safety and risk of fosthiazate as nematicide in cucumber field were evaluated in this study. An analytical method for determining the residues of fosthiazate in cucumber was developed. Mean recoveries and relative standard deviations in all samples ranged 85.3 ~ 95.0% and 5.7 ~ 13.3%. The half-lives of fosthiazate in cucumber root, leaf and fruit were 4.71 ~ 5.50 days, 3.52 ~ 4.78 days and 3.32 ~ 3.96 days. The residues in cucumber fruits were below the maximum residue limit (MRL) in China, based on the application dose of 900 g a.i./ha and the pre-harvest interval of 14 days. The transfer rates of fosthiazate from cucumber root to leaf were 17.48 ~ 46.03%, which were significantly higher than those of root to fruit (8.81 ~ 26.52%). These results indicated that fosthiazate was mainly distributed in cucumber root, and it was difficult to be absorbed by the fruit compared to the leaf. The long-term dietary intake risk assessment results showed that the risk quotient (RQ) ranged 20.04 ~ 36.25% and were less than 100%, which indicated that fosthiazate has a low risk for long-term dietary intake of cucumbers. Overall, our results would be considered as important references for safe and reasonable use of fosthiazate, monitoring and assessing the food safety, and protecting consumer health.