소면적 재배 작물 들깻잎 중 살충제 Bifenthrin과 Chlorfenapyr의 잔류양상

소면적 재배 작물 중 연속수확작물인 높은 들깻잎의 안전성 확보를 위하여 들깻잎 중 bifenthrin 및 chlorfenapyr의 잔류양상을 연구하였다. 확립된 분석법을 이용하여 회수율시험을 실시한 결과 bifenthrin 및 chlorfenapyr의 회수율은 81.9~104.8% 범위로 만족할만하였다. 들깻잎의 생육 기간중 bifenthrin과 chlorfenapyr의 잔류량 변화는 first order kinetics model을 적용하여 해석하였으며 이 식으로부터 산출된 감소상수는 bifenthrin에서 0.0724-0.0535 day-1, chlorfenapyr에서 0.0948-0.0821 day 1로 나타났다. 두 농약의 들깻잎 중 반감기는 bifenthrin의 경우 9.6-12.9일이었으며, chlorfenapyr는 7.3-8.4일이었다. 산출된 두 농약의 감소상수를 이용하여 pre-harvest residue limit(PHRL)을 산출한 결과 수확 10일전 들깻잎 중 bifenthrin 및 chlorfenapyr 의 잔류량이 각각 17.1 및 15.9 mg/kg일 경우 수확일에는 두 농약의 잔류허용기준인 7.0 및 10.0 mg/kg 이하로 잔류하여 안전할 것으로 예상되었다. BACKGROUND: It is important to understand residual patterns of pesticides applied on crops for ensuring their safety in agricultural products. However, there are few studies on the residual patterns of pesticides in minor crops, which are small in cultivation area. In this study, residual amounts of bifenthrin and chlorfenapyr sprayed on perilla leaf as a minor crop were investigated to know their residual patterns. METHODS AND RESULTS: Bifenthrin and chlorfenapyr were sprayed 2 or 3 times on perilla leaves at a week interval prior to harvest, and the perilla leaves were collected at 0, 1, 3, 5 and 7 days after the final application of pesticides. Recoveries for residual analysis of pesticides spiked on perilla leaves with concentrations of 0.1 and 0.5 mg/kg were 81.9-104.8%. The residual amounts of pesticides interpreted using first order kinetics model show that dissipation constants of bifenthrin and chlorfenapyr in perilla leaves were 0.0724-0.0535 and 0.0948-0.0821 day-1, respectively. In addition, the dissipation half-lives in perilla leaves were 9.6-12.9 days for bifenthrin and 7.3-8.4 days for chlorfenapyr. When pre-harvest residue limits (PHRL) of bifenthrin and chlorfenapyr at 10 days before harvest calculated on the basis of the dissipation constants and maximum residue limits of the pesticides were calculated as 17.1 for bifenthrin and 15.9 mg/kg for chlorfenapyr. CONCLUSION: Therefore, the PHRL calculated using the time-dependant residual patterns of pesticides in perilla leaves and their regression analysis may be used as experimental evidences in order to ensure the safety of pesticides in perilla leaves before harvest.