Residual Characteristics of Some Pyrethroid Insecticides in Korean Cabbage

In order to elucidate the residual characteristics of some pyrethroid insecticides commonly used for Korean cabbage, such as bifentbrin, lambda-cyhalothrin and deltametbrin, the test pesticides were sprayed onto the crop at recommended rate and doubled rate of the recommendation. Their detection limits were 0.004 mg and mean recoveries at the fortification levels of 0.04 and 0.2 mg were from 95.16 to 99.32 and from 86.81 to 103.73%, respectively. Half-lives were from 2.5 to 3.6 at the recommended rate and from 2.3 to 3.9 days at the doubled rate of the recommendation. Initial residue amounts of bifenthrin and lambda-cyhalothrin at the recommended rate and doubled rate of recommendation and of deltamethrin at the recommended rate were less than their MRL, whereas, in case of deltamethrin sprayed at doubled rate of the recommendation, the residue level exceeded its MRL. However, the residue levels of the pesticides in the crop sampled at harvest were less than their maximum residue levels and the ratios of the estimated daily intake (EDI) to acceptable daily intake (ADI) for the pesticides tested calculated from the residue data at harvest were less than 7%, suggesting that these pesticides would be safe for Korean cabbage from the residue concern