Parathion Residues as a Cause of Poisoning in Crop Workers

Abstract

The application of parathion as a pesticidal spray in fields and orchards leaves a residue that declines rapidly on most crops for the first few days and more gradually during a period of weeks. Persons not actually engaged in spraying but working among trees and vines thereafter run a risk of poisoning that depends on a number of factors. Eleven episodes of poisoning from contact with parathion residues, involving more than 70 persons, have been analyzed. The crops involved were pears, apples, grapes, citrus fruits, and hops. The workers were engaged in picking, thinning, cultivating, and irrigating. Absorption apparently was by the dermal rather than the respiratory route. It was favored alike by the removal of protective clothing and by the persistent wearing of contaminated clothing. Certain weather conditions may have increased the likelihood of contamination. One episode involving 16 cases occurred 33 days after the spraying. Regulations intended to minimize the hazards of using parathion need to be reviewed with respect to the poisonings that have occurred from the persistence of toxic residues.