BIOTRANSFORMATION AND DEPOSITION OF RESIDUES OF FENTHION AND OXIDATIVE METABOLITES IN THE FAT OF CATTLE

Yearling steers conditioned on either a low-or high-energy ration for 14 weeks were treated with a pouron formulation of 3% fenthion (Tiguvon, O, O-dimethyl O-[3-methyl-4-(methylthio)phenyl] phosphorothioate). When these steers were slaughtered at 3 or 10 days posttreatment, the omental, renal, and subcutaneous fat was collected and analyzed for fenthion and five oxidative metabolites. Residues of fenthion, fenthion sulfoxide, fenthion sulfone, and fenthion oxygen analogue were found in all samples at 3 days posttreatment. At 10 days posttreatment, no fenthion sulfone was present, the other two metabolites were found, and unchanged fenthion was found in the greatest concentration. Residues of fenthion oxygen analogue sulfoxide and fenthion oxygen analogue sulfone were not found in any samples. The levels of residues in the fat of steers on the low-energy ration were greater than the levels in the fat of steers on the high-energy ration. © 1979, American Chemical Society. All rights reserved.