Parathion dislodgeable residues

The procedure involves converting oxon to thion toxicity equivalents by multiplying the oxon value by its relative toxicity (ED of thion r ED,.q of oxon) in Table I. The ED. value is the aermal dose in ug/cnr of total body surface which produces 50% inhibition of red cell ChE activity 72 hours after application. The total thion and oxon level is then divided by the thion toxicity equivalents and the factor is multiplied by the safe level established for thion in Table I. This procedure was conducted for the dislodgeable residues of parathion-paraoxon, methidathion-methidathion oxon, and azinphosmethyl-azinphosmethyl oxon. The safe levels for the total disloggeable residues were determined to be 0.06, 0.2 and 1.6 ug/cm, respectively, for... 

Low urinary excretion of metabolites and a low (15% or less) cholinesterase depression were noted over 5 exposure days. In a reentry study of California citrus trimmers and pruners exposed to phosalone, results were unremarkable (15). No cholinesterase depression or urinary metabolites were noted. Reentry was at 14 and 21 days with exposure to 2.6 and 3.6 yg/cm2, respectively, on each reentry day. In a major study of peach thinners (previously referenced, ]2, J 4, J 6), lettuce harvesters, and artichoke harvesters, low or no urinary metabolites were observed and cholinesterase values were within the normal ranges. Phosdrin and methomyl had been applied to lettuce, and parathion and methyl parathion to artichokes. Dislodgeable residues were... 

Buck, N.A., B.J. Estesen, and G.W. Ware. 1980. Dislodgable insecticide residues on cotton foliage fenvalerate, permethrin, sulprofos, chlorpyrifos, methyl parathion, EPN, oxamyl, and profenofos. Bull. Environ. Contam. Toxicol. 24 283-288. 

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