On oral administration of 14C-fenitrothion [Sumithion(R), 0,0-dimethyl 0-(3methyl-4-nitrophenyl)phosphorothioate] labeled at the phenyl ring to Japanese quails at a single dose of 5 mg/ kg or to White Leghorn hens at daily dose of 2 mg/ kg for 7 days, 97 to 99% of the radiocarbon administered was excreted in the mixture of urine and feces within one day. The radioactivity eliminated into eggs was at most 0.2%, or 0.055 ppm equivalent to the parent compound. More than 18 metabolites were found in the excreta, among which 14 compounds were identified. The major metabolites were 3-methyl-4-nitrophenol and its sulfate conjugate which accounted for 70.5% of the dose in quails and 50.8% in hens. Desmethylfenitrothion and desmethylfenitrooxon were found as minor metabolites, and also several m-methyl oxidation products were detected. In vitro studies revealed that hen, quail, pheasant and duck liver enzymes possessed higher oxidation activity at the m-methyl group of fenitrooxon than that of mammalian liver enzymes, although these avian enzymes had extremely low 0-demethylate activity.

The lactating Japanese Sannen goats were treated orally with 14C-ring labeled fenitrothion [O, O-dimethyl O-(3-methyl-4-nitrophenyl)phosphorothioate, Sumithion(R)] at 0.5 mg/kg/day for 7 days. At 1 day after treatment, no residues of intact fenitrothion were found in the organs and tissues, and a little amount of aminofenitrothion was detected in digestive tracts (rumen, omasus and large intestine). The radiocarbon disappeared rapidly thereafter. The administered radiocarbon was essentially quantitatively excreted during a week post-treatment period; 50% of the dose were recovered in urine, 44% in feces, and 0.1 % in milk with a maximum of 0.011 ppm equivalent to the parent compound. The remaining radioactivity was further excreted, although gradually. The major metabolites in urine, feces and milk were O, O-dimethyl O-(3-methyl-4-aminophenyl)phosphorothioate (aminofenitrothion) and O-methyl-O-hydrogen O-(3-methyl-4-acetylaminophenyl)phosphate, and O, O-dimethyl O-(3-methyl-4-sulfo aminophenyl)phosphorothioate (Nsulfo aminofenitrothion), respectively. No intact fenitrothion nor fenitrooxon was found in milk, urine and feces.

3H-Cremart(R), O-ethyl O-(3-methyl-6-nitrophenyl) N-sec-butylphosphoramidothioate, labeled at the phenyl group is readily and substantially completely excreted, majorly into urine on oral administration to rat at 70 mg/kg. Less than 1% of Cremart initially given is present only in the feces, but no oxygen analog is detected in the excreta, although it is formed in the animal body. The major metabolites in the urine are 3-methyl-6-nitrophenol, 3-hydroxymethyl-6-nitrophenol and 3-carboxy-6-nitrophenol, free and conjugated with sulfuric and glucuronic acid, together with a trace amount in the excreta of the metabolites carrying intact P-0-C (aryl) linkage such as Cremart, 0-ethyl 0-(6-amino-3carboxyphenyl) N-sec-butylphosphoramidate, aminocremart and 0-ethyl 0-hydrogen 0-(3methyl-6-nitrophenyl)-phosphorothioate. No significant differences are observed between males and females in excretion and metabolism. Therefore, apparently Cremart is biodegradable and unlikely to leave any persistent residues in mammals. 3H-Cremart added to nutrient solution at 2. 0 ppm is steadily absorbed into bean plants, rice plants and carrots. The bulk of the absorbed 3H is present in the roots, and its level in the shoots is low. After 10-day cultivation Cremart accounts for 70 up to 85% of 3H absorbed in the plants, with other radioactive metabolites including cremart-oxon, 3methyl-6-nitrophenol as well as its glucoside and 0-ethyl 0-(3-hydroxymethyl-6-nitrophenyl) N-sec-butylphosphoramidothioate.