*3.5. BCFs and Management Concentration of Fluopyram in Soil*

The 95% confidence intervals of the BCF of scallion were determined from soil residues at DAP 0 and scallions at DAP 48, as shown in Table 5. The BCFs of scallions were in the range of 0.21–0.24 and 0.14–0.18 in trials A and B, respectively, which were lower than that of bell pepper leaves (0.32) and higher than that of tomato leaves (0.12) [7]. These results indicate that the uptake and accumulation capacity of fluopyram by scallions was intermediate between that of bell pepper leaves and tomato leaves.

**Table 5.** Bioconcentration factors (BCFs) of fluopyram calculated from residue estimates (95% confidence interval) in soil and scallions.


Based on the MRL in the crop and BCFs in this study, the management concentration in soil (MCsoil) was determined, which is the maximum tolerable level in soil caused by pesticides used during the cultivation of the preceding crop, thereby minimizing residual pesticide levels in rotational crops grown in contaminated soils and producing safe agricultural commodities. In the Republic of Korea, the MRL for fluopyram arising from unintentional contamination is set at 0.2 mg/kg for leaf-and-stem vegetables, including scallions. The minimum MCsoil for fluopyram was calculated as 0.83 mg/kg from the upper 95% confidence limit of the BCF. Therefore, the management concentration for fluopyram in the soil is proposed as less than 0.8 mg/kg. This threshold for fluopyram in the soil is likely to be set as a precautionary measure to ensure that scallions grown in soil contaminated with fluopyram will not be exposed to the MRL in scallions. If the concentration of fluopyram in the soil is found to be higher than the proposed management level of 0.8 mg/kg, appropriate measures should be taken to mitigate the associated risks. These measures may include delaying planting of seedlings, tillage, and soil dressing. These actions are generally taken to reduce the level of fluopyram in the soil to an acceptable level, in order to protect the rotational crops and the environment.
