Safe Application of 75% Trifloxystrobin–Tebuconazole as Water-Dispersible Granules in Paddy Based on Residue and Dietary Risk Assessment

Abstract

The present study describes the development of a highly effective approach for determining the residue distribution and dissipation of trifloxystrobin and tebuconazole, and their risk assessment in brown rice, husk, straw, and grain using high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS). The current study provides considerable novel information regarding the safe utilization of a mixture of trifloxystrobin and tebuconazole in paddy production. The samples demonstrated a range of mean recoveries between 72% and 86%, with a 1.1–9.2% relative standard deviation (RSD). The limits of quantification (LOQ) and half-lives (t1/2) for brown rice, husk, straw, and grain were, respectively, established to be 0.001–0.01 mg/kg and 4.1–7.7 days. The concentrations of terminal residues in the brown rice, husk, straw, and grain were, respectively, found to be 0.02–0.05, 0.03–0.11, 0.02–0.07, and 0.02–0.05 mg/kg after being treated twice at 168.75 g a.i./ha with 21 and 28 days of pre-harvest intervals (PHIs). Trifloxystrobin and tebuconazole presented a non-negligible chronic risk to human subjects, as evidenced by a risk quotient (RQ) value of less than 1.