Persistence behaviour of imidacloprid and its metabolites in soil under sugarcane

• DOI: 10.1007/s10661-013-3536-1
• Publication Date: 2013-11-25T03:07:38Z
• Authors: Smriti Sharma; Balwinder Singh
• Keywords: 2. Zero hunger; Insecticides; Imidazoles; Pesticide Residues; Nitro Compounds; 01 natural sciences; 6. Clean water; Saccharum; Neonicotinoids; Soil; Soil Pollutants; Environmental Monitoring; Half-Life; 0105 earth and related environmental sciences

The persistence and metabolism of imidacloprid in soil under sugarcane were studied following application of imidacloprid at 20 and 80 g active ingredient (a.i.) ha(-1). Soil samples were collected at different time intervals (7, 15, 30, 45, 60 and 90 days after application), and the residues of imidacloprid and its metabolites (6-chloronicotinic acid, nitrosimine, imidacloprid-NTG, olefin, urea and 5-hydroxy) were quantified by high-performance liquid chromatography. In soil, the total imidacloprid residues were mainly constituted by the parent compound followed by 6-chloronicotinic acid, nitrosimine and imidacloprid-NTG metabolites. Maximum residues of imidacloprid and its metabolites were 4.29 and 7.81 mg kg(-1) in soil samples collected 7 days after the application of imidacloprid at 20 and 80 g a.i. ha(-1), respectively. At both doses, these residues declined to below the detectable limit in soil after 90 days of application. Olefin, urea and 5-hydroxy metabolites were not detected in soil. Dissipation of total imidacloprid residues did not follow the first-order kinetics with a coefficient of determination value of 0.883 and 0.838 for the recommended dose and four times the recommended dose, respectively. The half-life (T(1/2)) value of total imidacloprid was observed to be 10.64 and 10.10 days for the recommended dose and four times the recommended dose, respectively.