FATE OF WHEAT BOUND MALATHION RESIDUES IN RATS DURING GESTATION

Malathion [S-1,2-di(ethoxycarbonyl) ethyl 0,0-dimethyl phosphorodithio ate], treated wheat when stored for 28 months at 20-degrees-C with or without food grade white mineral oil on grains contained about 62 and 79% of the applied insecticide as bound residues, respectively. These bound residues were present mainly in the form of the parent compound. The stored wheat containing bound malathion residues, as well as whea t material freshly spiked with malathion were fed to rats during gesta tion. No residues of malathion and/or metabolites were detected in uri ne, feces and body tissues. Further no significant effect on body weig ht, serum chemistry and cytochrome P450 levels were observed in the mo thers. There was no evidence for the histopathological alteration or t eratogenic anomalies in the fetuses. However, placental transfer of ma lathion was indicated by the presence of the insecticide residues in f etuses from rats fed wheat material containing bound residues.