Exposure of apple thinners to parathion residues

Abstract

In studies of potential exposure of a volunteer working under controlled conditions during apple hand-thinning operations at 1, 24, 48, 72, 96, 168, and 240 hr after application of conventional 0.03% parathion spray, both dermal and respiratory exposure values were greater where water-wettable powder formulations were used than where emulsifiables were used. Residue levels of parathion on leaves from the two types of applications were about the same. Only trace amounts of paraoxon could be detected at one and seven days after application. Highest exposure values (14.2 mg/hr dermally and 0.15 mg/hr respiratorily) were obtained within 24 hr of application. Exposure was considerably less after residues were 72 hr old. Greatest exposure was on the forearms and hands. Urinary p-nitrophenol excretion indicated slightly more absorption following exposure in water-wettable powder experimental plots. Potential exposure values indicate that absorption could reach hazardous levels after one or two hr of work, even at the 96-hr residue period, if all the pesticide were absorbed. Considering that only a small fraction of the total amount would be absorbed, it is calculated that at 75-hr residue period poisoning should not occur. There was no significant change in blood cholinesterase activity of the volunteer worker. Variation in spray deposit within an orchard due to poor tank mixing did not appear to be great enough to be considered an important factor affecting exposure.

A Comparison of Cholinesterase Activity after Intravenous, Oral or Dermal Administration of Methyl Parathion

“…Numerous cases of acute toxicity to organophosphorus insecticides, including methyl parathion, among agricultural workers have been reported [5,21,37,44]. Yet, only recently, with the advent of its use in private residences and businesses throughout the south-central United States, has exposure to methyl parathion become a public health concern.…”

Application of a dermal self‐exposure model to worker reentry

“…Widespread dermal exposure to toxicants exists in agricultural field reentry, where exposure to insecticides capable of cholinesterase inhibition has resulted in many cases of illness (Milby, 1974) and a few fatalities (Krook et al, 1971). Reentry poisoning cases have been most numerous in California citrus orchards (Gunther et al, 1977), but have also occurred in Washington apple orchards (Wolfe et al, 1975), North Carolina tobacco fields (Guthrie et al, 1972), Florida sweet corn fields (Davies et al, 1976), and New Jersey vegetable fields 462 C. S. SKINNER AND W.W. KILGORE (Quinones et al, 1976). Studies by Ware et al (1973), Wolfe et al (1975), and Spear et al (1977) demonstrated that dermal exposure far exceeds inhalation exposure in the field.…”

Percutaneous penetration of [14C] parathion in the mouse: Effect of anatomic region

“…Widespread exposure of workers to toxicants exists in agricultural field reentry, where cholinesterase inhibition may result from dermal exposure to foliar pesticide residues (Ware et al, 1975;Wolfe et al, 1975;Spear et al, 1977). In the past two decades, cases of reenetry poisoning have been most numerous in citrus orchards sprayed with parathion (Gunther et al, 1977).…”