Persistence of dicofol residues in cotton lint seed, and soil

Abstract

A supervised field trial was conducted at the CCS Haryana Agricultural University, Hisar to assess the residues of dicofol on cotton, during Kharif season, 2008. Dicofol (Kelthane 18.5EC) was applied at 500 g a.i./ha (T₁) and 1,000 g a.i./ha T₂) after 105 days of sowing of cotton crop (Varity Cotton/H-1226). Soil samples were collected on 0 (1 h after treatment), 3, 7, 10, 15, 30, and 60 days after spray and cotton samples were collected at harvest. Samples were processed and residues were quantified by GC-ECD system equipped with capillary column. Limit of detection and limit of quantification (LOQ) were 0.001 and 0.010 mg kg^− 1, respectively, for soil and LOQ for cotton lint and seed was 0.020 mg kg^− 1. Initial residues of 0.588 and 1.182 mg kg^− 1 in soil reached below detectable level (BDL) of 0.010 mg kg^− 1 in T₁ and to the level of BDL (0.010 mg kg^− 1) in T₂ at harvest (60 days after treatment). In 60 days, residues dissipated almost completely (100 and >99%) in both the treatments. Half-life period was calculated as 8.57 days at single dose and 8.69 days at double dose in soil. Residues of dicofol were detected in cotton lint to the levels of 0.292 and 0.653 mg kg^− 1 and in seed 0.051 and 0.090 mg kg^− 1 in T₁ and T₂ doses, respectively at harvest. Residues in cotton seed were below MRL value of 0.01 mg kg^− 1 in both the doses.