A rapid, sensitive, and effective
multiresidue analytical method
was established to investigate the degradation rate and final residues
of bifenthrin, bifenazate, and its metabolite bifenazate–diazene
in apples, and the dietary risk of consumers was evaluated. The residues
of bifenthrin, bifenazate, and bifenazate–diazene in apple
samples from 12 different apple-producing areas of China were determined
by high-performance liquid chromatography tandem mass spectrometry
(LC-MS/MS). The average recoveries of the three compounds in apples
were 88.4–104.6%, and the relative standard deviations (RSDs)
were 1.3–10.5%. The limit of quantification (LOQ) for each
compound was 0.01 mg/kg. Although the degradation half-lives of bifenthrin,
bifenazate, and bifenazate–diazene were 17.8–28.9, 4.3–7.8,
and 5.0–5.8 days, under good agricultural practice (GAP) conditions,
the final residues of bifenthrin, bifenazate, and the sum of bifenazate
and its metabolite bifenazate–diazene in apples were <0.01–0.049,
< 0.01–0.027, and <0.02–0.056 mg/kg, respectively,
which were lower than the maximum residue limit (MRL) in China. By
comparing the deterministic model with the probabilistic model, the
results of the probabilistic model at the P95 level (12.91–48.9%
for bifenthrin, 17.48–52.01% for bifenazate including its metabolite)
were selected as reasonable assessment criteria for chronic dietary
risk, and the acute risk was at the P99.9 level (3.00–15.59%
for bifenthrin). Although the exposure risk calculated by both the
deterministic model and the probabilistic model was less than 100%,
the risk to children is significantly higher than that of the general
population. This suggests that in future research and policy making,
we should pay more attention to the risk of vulnerable groups such
as children.