본 연구는 시설재배지 내에서 고추 등에 처리된 imicyafos 5% 입제의 후작물인 알타리무에 대한 후작물 흡수이행성 및 잔류특성을 구명하기 위해 수행하였다. 포트시험의 결과를 바탕으로 포장시험의 후작물식재기간 (Plant Back Interval, PBI)를 설정하여 시험하였다. Imicyafos 5% 입제를 6 kg / 10 a 기준으로 포트와 포장시험 처리구에 각각 처리하였으며, 포트시험에서는 1/5000a 포트에 15 cm 깊이의 토양을 약제와 혼화하여 담은 후 알타리무 파종 전 30일 (PBI 30), 파종당일 (PBI 0) 처리 후 재배하였다. 포장시험에서는 파종 64일(PBI 60), 35일 (PBI 30), 4일 (PBI 0) 전 나지 토양에 약제를 처리 후 15 cm 깊이로 경운한 다음 알타리무를 파종하여 재배하였다. 토양시료의 imicyafos 정량한계는 0.01 mg/kg이며 회수율은 0.01, 0.1, 1.0 mg/kg 수준에서 87.6~93.7%이었다. 작물시료의 정량한계는 0.002 mg/kg이며, 회수율은 0.002, 0.01, 0.1 mg/kg 수준에서 무잎 88.1~93.2%, 무뿌리 93.0~111.1%이었다. 포트시험의 파종 후 69일 (완숙시료)차에 채취한 토양, 무잎, 무뿌리에서의 잔류량은 PBI 30에서 0.22, 0.015, 0.018 mg/kg이었으며, PBI 0에서는 0.21, 0.018, 0.023 mg/kg으로 검출되었다. 포장시험 처리구의 경우 포트시험 결과를 고려하여 PBI 60 처리구를 추가하였고, 시험한 결과 파종 후 43일 (완숙시료)차에 채취한 토양, 무잎, 무뿌리의 잔류량은 PBI 60에서 0.13, 0.005, 0.009 mg/kg, PBI 30에서 0.25, 0.035, 0.013 mg/kg, PBI 0에서 0.43, 0.092, 0.066 mg/kg으로 검출되었다. 시설재배지 내 토양의 파종기에서 수확기까지의 반감기는 약 17일이었다. Imicyafos 5% 입제를 사용하였을 경우 최종약제처리 후 60일 이상 기간이 경과한 후 알타리무를 파종하는 것이 안전하다고 판단했으며, 후작물에 영향을 미치는 요인이 다양함으로 추가적인 연구가 필요하다.
Pesticides are essential agricultural materials to increase production, reduce the labor force, and improve crop quality. However, they are toxic chemicals and are required safety control by residue regulations (MRL, PHRL, etc.) To secure the safety of pesticide residues, the Positive List System, which applies a uniform standard of 0.01 mg/kg for agricultural products for which MRL has not been set, was introduced and implemented in 2019 in Korea. The 0.01 mg/kg of pesticide residue in the soil can be uptaken and accumulated to crops during crop cultivation. Plant Back Interval (PBI) is required to protect against unintentional contamination of pesticides in crops. Imicyafos is a frequently used pesticide as an organophosphate nematicide in liquid and granule form. Here, the residues in soil and crops were investigated for PBI estimation after the treatment in crop soil. 5% Imicyafos granules were applied 6 kg/10 a to a pot and crop field. For the pot test, 15cm-depth soil was mixed with the imicyafos 30 days before sowing days (PBI 30 days) and on sowing (PBI 0 days). For the field test, the imicyafos were applied on the bare soil and then mixed with 15 cm depth soil at 64 days (PBI 60 days), 35 days (PBI 30 days), and 4 days (PBI 0 days) before sowing. And radishes were sowed and cultivated. In the quantitative analysis of residual imicyafos, the quantification limit was 0.01 mg/kg, and the recovery was 87.6-93.7% in radish leaf and 88.1~93.2% in radish root in the range of 0.01-1.0 mg/kg. Residual amounts were investigated at 69 days after sowing in pot test were 0.22, 0.015, and 0.018 mg/kg for PBI 30, and 0.21, 0.018, and 0.023 mg/kg in soil, the leaves and the roots for PBI 0, respectively. The residual amounts in soil, radish leaves, and radish roots collected at 43 days after sowing were 0.13, 0.005, and 0.009 mg/kg at PBI 64 days in the field, respectively. As the PLS uniformity standard, PBI 35 days and PBI 0 days exceeded 0.01 mg/kg. Therefore the sustainable residue issue in the soil after the imicyafos treatment would cause the unintentional residue problem in the postharvest crop, and the PBI should be further studied for the prevention of unintentional contamination in crops.