Residual Characteristics of Etofenprox and Methoxyfenozide in Chinese Cabbage

Two insecticides, commonly used for Chinese cabbage, etofenprox and methoxyfenozide, were subjected to a field residue trial to evaluate safeties of the residues at harvest. The pesticides were sprayed onto the crop at recommended and double doses 10 days before the prearranged harvest and then sampling was done at 0, 1, 2, 3, 5, 7, 10, and 12 days after spraying. The amounts of pesticides residues in the crop were analyzed by chromatographic methods. Limits of detection (LODs) of both etofenprox and methoxyfenozide were $0.01mg\;kg^{-1}$ and mean recoveries were $96.76{\pm}2.67$ (CV=2.76%) and $95.84{\pm}2.57%$(CV=2.69%) in case of etofenprox and $103.26{\pm}3.21$ (CV=3.11%) and $94.50{\pm}1.35%$(CV=1.43%) in case of methoxyfenozide, respectively. Biological half-lives of etofenprox and methoxyfenozide were 3.2 and 3.5 days at the recommended dose and 2.7 and 3.5 days at the double dose, respectively. Initial residue levels of the pesticides at the recommended and double doses exceeded their MRLs, but final residue levels of the pesticides in the crop samples at harvest were less than their MRLs. The ratios of the EDI to ADI by intake the crop harvested 10 days after spraying were less than 4% of their ADIs, representing that residue levels of two pesticides at harvest were evaluated as safe.

Etofenprox와 Methoxyfenozide의 배추 중 잔류특성

배추에 등록되어 일반적으로 사용하고 있는 살충제 etofenprox와 methoxyfenozide를 살포하여 생물학적 소실곡선식을 통한 수확 전 약제살포 후 경과일수별 잔류량을 예측하였다. 두 시험 농약의 검출한계는 $0.01mg\;kg^{-1}$이었고, 분석법의 회수율은 etofenprox와 methoxyfenozide에서 각각 96.76-95.84%, 94.50-103.26%이었다. 시험농약의 반감기는 기준량 처리구에서 etofenprox와 methoxyfenozide에서 각각 3.2일, 3.5일 이었고, 배랑 처리구에서는 각각 2.7일, 3.5일 이었다. 시험 농약의 약제 살포직후 농도는 잔류허용기준을 초과하였으나, 수확예정일의 시료중 시험농약의 농도는 모두 잔류허용기준 미만이었으며, 수확예정일의 잔류량으로 산출한 시험농약의 ADI 대비 EDI의 비율은 기준량과 배량 처리구에서 모두 4%미만으로 안전한 것으로 평가되었다.