Effect of bifenthrin application at different maturity stages on its dissipation and residues in kumquat (Citrus japonica) and dietary intake risk assessment.

Bifenthrin is a pyrethroid pesticide widely used on kumquats, but the residues in the peel and pulp after bifenthrin application at different maturity stages of kumquats have not been evaluated. This study developed a simple and rapid high-performance liquid chromatography (HPLC) method for the quantitative analysis of bifenthrin residues in whole fruit, kumquat peel, kumquat pulp, and soil. The results showed that regardless of whether bifenthrin was applied one or three times during the near-mature period, the half-lives of the fruit peel and fruit pulp were longer than those in the immature period. Kumquat fruit residues decreased with time at both maturity levels. The residues of bifenthrin in near-mature fruit exceeded the MRL in Guangxi and Fujian 14 days after the three applications of bifenthrin, suggesting that this issue should be focused on in kumquat production and supervision. However, for bifenthrin application in either the near-mature or the immature fruit period, the calculated risks for chronic dietary intake of kumquat were well below 100%. The data demonstrate that the chronic dietary intake risk of bifenthrin through kumquat consumption is low and within acceptable limits. These results provide a reference and risk assessment data for the safe and rational use of bifenthrin insecticides.