Fate of Carbofuran in Laying Hens1

Abstract

Eighty percent of a single oral dose, 2.7 mg/kg, of carbofuran (2, 3-dihydro-2,2-dimethyl-7-benzofuranyl Nmethylcarbamate-7a-14C) was eliminated in the feces by the end of a 10-day study period. All eggs contained small amounts of carbofuran equivalents, with the maximum, 0.13 ppm, occurring on the 4th day. Residues in the liver and kidney were about 2.6 ppm carbofuran equivalents 6 hours after treatment but declined to 0.2 ppm by 24 hours. Muscle and fat contained about 0.3 ppm residues at 6 hours and less than 0.1 ppm by 24hours. Hydroxylation of the no. 3 carbon of carbofuran and hydrolysis of the carbamate ester were the predominant pathways in the metabolism of this insecticide by laying hens. An identical experiment using carbofuran carbonyl-14C, but at a dosage rate of 0.3 mg/kg, supported the above findings. However, the value of quantitative data from the latter study was limited by indications that carbon-14 dioxide resulting from hydrolysis was incorporated into naturally occurring body chemicals.