Effect of processing on 14C-chlorfenvinphos residues in maize oil and bioavailability of its cake residues on rats.

Maize seeds obtained from 14C-chlorfenvinphos treated plants contained 0.12% of the applied dose. The insecticide residues in crude oil, methanol and cake amounted to 10%, 6% and 69%, respectively of original residues inside the seeds. The 14C-activity in the crude oil could be a gradually reduced by the refining processes. The alkali treatment and bleaching steps are the most effective steps in these processes. The refined oil contained small amount of the 14C-residues originally present. The major residues in processed oil contain the parent compound, in addition to five metabolites of the insecticide. When rats fed the extracted seeds (cake), the bound residues were found to be considerably bioavailability. After feeding rats for five days with the cake, a substantial amount of 14C-residues was eliminated in the urine (59.5%), while about 20% excreted in the feces. About 15% of the radioactive residues were distributed among various organs.