A survey of blood cholinesterase activity and urinary p-nitrophenol excretion of occupational groups exposed to parathion was made in central Washington in 1958. Only the group with the highest potential exposure to parathion (mixing-plant personnel) showed a definite decrease in cholinesterase level during exposure. The enzyme diminution for this group occurred only with the erythrocytes. All 5 of the highest exposure groups (mixing-plant personnel, commercial ground applicators, part-time ground applicators, aircraft application workers, and workers in orchards) excreted significant quantities of p-nitrophenol during the period of their exposure. The excretion of measurable amounts of p-nitrophenol in the presence of normal plasma and red blood cell cholinesterase levels is important as an indication that p-nitrophenol excretion is a more sensitive measure of exposure to parathion than is blood cholinesterase activity. The average p-nitrophenol excretion of the residents-near-orchard group was not significant.

Included in PB-280 565, Journal articles on toxicology. Group 12.