Final Residue, Degradation Dynamics, and Dietary Risk Assessment of Bifenazate in Citrus and Soil

ABSTRACT

To ensure the safe application of 50% bifenazate water dispersible granule (WDG), field trials were conducted in Guangdong, Guangxi, and Hunan Provinces of China for 2 consecutive years to evaluate the final residue and degradation dynamics of bifenazate in citrus and soil. Bifenazate was analyzed by the optimized quick, easy, cheap, effective, rugged, and safe (QuEChERS) combined with the high-performance liquid chromatography (HPLC) method, which achieved good linearity over the range of 0.01–5.0 mg·L⁻¹ with a correlation coefficient r = 0.9999. The average recoveries for bifenazate in citrus and soil were 77.7–105.0%, with relative standard deviations (RSDs) of 3.5–8.7%. The degradation of bifenazate in citrus and soil were consistent with the first-order kinetic equation, the half-lives of bifenazate in citrus and soil were 9.46–27.29 and 3.81–17.24 days, respectively. The final residues of bifenazate in citrus and soil were 0.012–1.582 mg·kg⁻¹. On the 21st day after the last application, bifenazate decreased to below the maximum residue limit (MRL) stipulated by China. RQ_chronic suggested that 50% bifenazate WDG be sprayed once with dosages ranging from 250 to 375 mg a.i.·L⁻¹ is safe for humans.

KEYWORDS:

• Field trials
• pesticide contamination
• soil
• QuEChERS
• HPLC

Acknowledgments

This research was financially supported by the National Key Research and Development Program of China (No. 2023YFD1700700).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirmed that the data supporting the findings of this study are available within the article.

Additional information

Funding

This research was financially supported by the National Key Research and Development Program of China (No. 2023YFD1700700).