Urinary excretion of paranitrophenol and alkyl phosphates following ingestion of methyl or ethyl parathion by human subjects.

Nitrophenolic and alkyl phosphate metabolites of methyl and ethyl parathion in the urine of human subjects soon after doses of 1 to 4 mg have been ingested. Particular alkyl phosphates can serve as specific indices of absorption of the respective parathions. Paranitrophenol and diethyl thiophosphate are rapidly eliminated in the urine, while excretions of dimethyl phosphate, and particularly diethyl phosphate, are more protracted. Cumulative excretions of paranitrophenol and alkyl phosphates exhibit sufficient dose-dependence at convenient intervals following parathion ingestion to encourage use of metabolite measurements in estimating occupational absorption of the parathion insecticides.