Dissipation Dynamics of Imidacloprid Residue in Different Saline Soils

Abstract

A method was developed for determining imidacloprid in soil using high performance liquid chromatography with UV-vis detector. The dissipation of imidacloprid in saline soil was also investigated under field and laboratory controlled conditions. The average recoveries ranged from 84.4 to 88.1% with relative standard deviations of 2.0 to 3.2% at three spiking levels (0.05, 0.5 and 5.0 mg/kg) in soil matrix. Under the field conditions, the half-life of imidacloprid in soil ranged from 8.6 to 11.4 days in Dongying and from 9.3 to 12.1 days in Binzhou. The dissipation rates of imidacloprid were almost same in the two locations. Under the laboratory conditions, the half-life of imidacloprid in soil with 0.3% NaCl was slightly longer than that in the soil without NaCl, which indicated that the dissipation of imidacloprid could be retarded in soil under salinity stress. These results could provide guidance for risk assessment and proper use of imidacloprid in relative saline regions.