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Inhalation and oral toxicity studies of ethyl parathion administered acutely and subacutely to the rat and dog
  • Published Date:
    1974
  • Language:
    English
Filetype[PDF - 4.10 MB]


Details:
  • Corporate Authors:
    Aberdeen Proving Ground (Md.).‏ Edgewood Area‏. Toxicology Division. ; National Institute for Occupational Safety and Health. ;
  • Document Type:
  • Description:
    I. Introduction -- II. Experimental -- II. A. Inhalation toxicity -- II. B. Oral toxicity -- III. Results and discussion -- III. A. Inhalation effects of ethyl parathion -- III. B. Oral effects of parathion -- IV. Summary and conclusions.

    Handwritten on title page: “Parathion -- inhalation and oral toxicity studies on rats and dogs performed for NIOSH by Toxicology Division, Edgewood Arsenal, Aberdeen Proving Ground, Maryland, 89 pages.”

    Acute and subacute oral and inhalation toxicity of ethyl parathion (56382) was studied in male Sprague-Dawley-rats crossed with Wistar-rats and male Beagle-dogs. Experimental animals received single acute or subacute doses administered over 6 weeks. Median lethal concentration (LC50) for rats in acute inhalation studies was 84.00 milligrams per cubic meter (mg/m3). The red blood cell (RBC) median cholinesterase activity inhibition concentration was 5.43mg/m3, and the plasma median cholinesterase activity inhibition concentration was 7.28mg/m3. Toxic signs included tremors, convulsions, salivation, respiratory difficulty, and death. Dogs were acutely exposed to concentrations ranging from 0.0153 to 37.13mg/m3. Cholinesterase activity was inhibited at all exposure concentrations. In acute oral studies, the LD50 for rats was 6.85mg/kilogram (kg), the RBC median cholinesterase activity inhibition concentration was 2.58mg/kg, and the plasma median cholinesterase activity inhibition concentration was 2.5mg/kg. Tremors, salivation, convulsions, prostration, and death were observed. In dogs, the acute oral LD50 was 8.27mg/kg, the RBC median cholinesterase activity inhibition concentration was 1.5mg/kg, and the plasma median cholinesterase inhibition activity concentration was 1.67mg/kg. Tremors, convulsions, and death were observed. In subacute inhalation studies, 0.01mg/m3 had no effects in rats, whereas doses of 0.10 and 0.74mg/m3 had moderate and pronounced effects, respectively. In dogs, 0.001mg/m3 subacute inhalation exposure had no effects, whereas 0.01 and 0.20mg/m3 had moderate and pronounced effects, respectively. In subacute oral toxicity tests the ethyl parathion concentrations producing no effect, moderate effects, and pronounced effects on RBC and plasma cholinesterase activity in rats were 0.05, 0.10, and 0.25mg/kg, respectively. The corresponding values in dogs were 0.05, 0.10, The authors suggest that human exposure levels can be predicted from observed effects on RBC or plasma cholinesterase activity.

    NIOSHTIC No. 00134578

  • Supporting Files:
    No Additional Files