Research within the Coordinated Programme on Isotopic-Tracer-Aided Studies of Chemical Residues in Cotton Seed, Oil, Feed and Related Products. Final Report for the Period 1 November 1974 - 14 December 1980

摘要

Exp 14 C-methyl and exp 14 C-ring-labelled carbaryl (1-naphthyl-N-methyl carbamate) were used to study the fate and magnitude of the insecticide in the plant and cotton seed products. Under conditions of actual agricultural practice, 0.08-0.09, 0.23-0.30 and 0.05 mg/kg of exp 14 C-residues were found in the seed, crude oil and cake respectively. In oil, the residue was resolved into 4 compounds, 2 identified as carbaryl and 1-naphthol. Residues from the soil did not exceed 0.3 mg/kg after the first week and declined to 0.1 mg/kg after 5 weeks. Parallel experiments were conducted under field conditions using exp 14 C-phenyl leptophos (4-bromo-2,5-dichlorophenyl methyl phenyl phosphorothioate). Leptophos residues were determined in the cotton seed products during 1975, 1976 and 1977, with mean values for leptophos residues in the cotton seed, crude oil and cake of 0.26, 1.10 and 0.07 mg/kg, respectively. Experiments with non-labelled monocrotophos (3-(dimethoxy phosphinyloxy)-N-methyl cis-crotonamide) gave residues of 0.30, 1.56 and 0.02 mg/kg in the seed, crude oil and cake, respectively. Carbaryl residues in two local maize varieties were determined by a colorimetric method. Cooking in aqueous, oil or aqueous-oil media led to 63-83% loss of carbaryl residues, after 30 minutes. Storage of corn oil for one year had essentially no effect on the concentration of carbaryl residues under laboratory conditions (. (Atomindex citation 12:626976)