Risk Assessment of Trifloxystrobin in Chinese Cabbage by Foliar Application and Drenching

Trifloxystrobin standard was analyzed by high performance liquid chromatography (HPLC). The recovery of the trifloxystrobin and it's metabolite CGA321113 were $84.6{\sim}95.3%$ and $86.4{\sim}87.3%$ and their detection limits for both of them were 0.04 mg $kg^{-1}$. In case of foliar application in the chinese cabbage (Brassica campestris L. ssp pekinnensis (Lour.) Rupr.), the amount of the residue of trifloxystrobin was above the maximum residue level (temporary MRL, 0.5 mg $kg^{-1}$) when it was treated either two times three to five days before harvest or three times three to seven days before harvest. Whereas in case of drenching the mount of the residue was below the temporary MRL, the residues in the cabbage in both the cases where the recommended amount (150 mL of the solution diluted 1500 times) and double of the amount were treated were 0.16 and 0.31 mg $kg^{-1}$, respectively. In conclusion, it should be safe to apply the trifloxystrobin (22% WP) in the soil of cabbage field abiding by the tentative recommendation level, but for the foliar application it appeared inappropriate.

경엽 및 관주처리에 따른 배추 중 Trifloxystrobin의 안전성 평가

HPLC에 의한 배추 중 trifloxystrobin의 회수율은 $84.6{\sim}95.3%$이었고 대사산물인 CGA321113의 회수율은 $86.4{\sim}87.3%$이었으며, 검출한계는 모두 0.04 mg $kg^{-1}$이었다. 경엽처리시 배추 중 trifloxystrobin 잔류량은 수확 5일과 6일전 2회 처리, 수확 3일과 7일전 3회 처리에서 모두 농약잔류허용기준(temporary MRL, 0.5 mg $kg^{-1}$)을 초과하였다. 관주처리 배추에서의 trifloxystrobin 잔류량은 기준량(1500배 희석액 주당 150 mL) 및 배량(1500배 희석액 주당 300 mL)처리에서 각각 0.16, 0.31 mg $kg^{-1}$으로 MRL 미만이었다. 따라서 살균제 trifloxystrobin(22% 액상수화제)를 사용하여 배추 재배시 농약잔류허용기준에 의하여 토양처리가 안전할 것으로 사료되며 경엽처리시 안전사용기준으로 부적합하다고 판단된다.