Pyrethroid Degradation Law, Migration In The Soil

Under laboratory conditions, the transportation and degradation trends of three pyrethroids, bifenthrin, cyhalothrin and deltamethrin in the snuff soil of Nanjing were studied, and the trends of these three pyrethroids were also contrasted. GC-ECD was used to determine the pyrethroids. The transportation trends of pyrehtroids were investigated by simulating soil columns in laboratory. The results show that these three pyrethroids are all difficult to move in the soil with low pH value. The abilities of transportation of cyhalothrin, bifenthrin and deltamethrin are enhanced in turn, mainly due to the difference of water-solubility of these three pyrethroids. The degradation experiments indicate that the half-life values of bifenthrin, cyhalothrin and deltamethrin in the snuff soil of Nanjing are 63.59d, 16.95d and 10.61d respectively, they are all low-level residue pesticides. In addition, based on the method of GC-MS, the methods of GC-MS-SIS and GC-MS-MS were developed to determine these pyrethroids in environmental soil samples simultaneously. By using these methods, the influence of impurity can be effectively avoided, and are more sensitive and accurate while detecting these pyrethroids in trace level.