Degradation and Persistence of Carbofuran in Peanut and Soil in Field Trails as Determined by GC-MS

This paper investigated the analytical method of degradation and persistence of carbofuran, its metabolite 3-hydroxy carbofuran in peanut seeds, fronds and soils in field trial using gas chromatography mass spectrometry (GC-MS). Carbofuran 3GR formulation (3g a.i./100g) was applied at dosages of 2250 and 3375g ha-1in furrow at sowing peanut seeds in the fields of Langfang, Hebei province and Jinan, Shandong province, China, respectively. The soil and the plant samples were collected at different intervals and the residues of carbofuran and 3-hydroxy carbofuran were analyzed by GC-MS. The degradation kinetic result showed that the degradation of carbofuran in peanut fronds in Jinan and Langfang can be well predicted with equation: C=1.2839e-0.1733tand C=0.5731e-0.1567t, with a half-life about 4.0 and 4.4 days respectively. For the degradation of carbofuran in soils, the result coincides well with equations: C= 4.2057e-0.2229t, and C= 5.4014e-0.1499t, with half-life of 3.1 and 4.6 days for Jinan and Langfang, respectively. The pH, organic matter and clay content as well as the climatic temperature play an important role in the degradation of carbofuran in soils. 3-hydroxy carbofuran dissipated rapidly both in peanut fronds and soils, it was not detectable 7 days after treatment for all treatment, the concentration of carbofuran and 3-hydroxy carbofuran in peanut seeds at harvest time were lower than either the maximum residue limit in China or the EUs maximum residue limit of 0.1 mg kg1. Based on the data from this investigation, the use of carbofuran in peanut could be considered to be safe.