Dissipation behavior of hexaconazole and kresoxim-methyl residues in ginseng and soil under field conditions.

The dissipation and terminal residues of a fungicide suspension (5% hexaconazole, 25% kresoxim-methyl) in ginseng and soil were investigated by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). At fortified levels of 0.01, 0.02, and 0.20 mg kg(-1), the recoveries of hexaconazole and kresoxim-methyl were in the range of 80.6∼94.8% and 82.4∼98.8% with relative standard deviation of 3.42-9.12% and 3.19-8.58%, respectively. The half-lives were 7.09-10.73 days in root, 6.80-7.95 days in stem, 5.31-8.49 days in leaf, and 6.30-7.97 days in soil. The terminal residues were all below the maximum residue limits (MRLs) of EU and South Korea. Risk assessment results indicated that the risk of hexaconazole and kresoxim-methyl use in ginseng at dosage of 60-90 g a.i. ha(-1) was negligible to humans. This work would help the government to establish the MRL and provide guidance on the proper and safe use of hexaconazole and kresoxim-methyl in ginseng.