© 1986 Oxford University Press
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Acute, 14-Day Repeated Dosing, and 90-Day Subchronic Toxicity Studies of Potassium Picloram1,2
Department of Pharmacology and Toxicology, Medical College of Virginia Virginia Commonwealth University Richmond Virginia 23298 *U.S. Environmental Protection Agency 26 West St. Clair Street, Cincinnati, Ohio 45268
Acute, 14-Day Repeated Dosing, and 90-Day Subchronic Toxicity Studies of Potassium Picloram. HAYES, J.R., CONDIE, L.W., AND BORZELLECA, J.F. (1986). Fundam. Appl. Toxicol. 7,464-470. Potassium picloram was administered either by gavage (acute studies) or in drinking water to male and female Sprague-Dawley-derived rats (14-day and 90-day studies). The acute oral LD50 was 950 mg/kg (812-1120) for males and 686 mg/kg (599-786) for females. Depression, prostration, ataxia, tremors, and convulsions preceded death. There were no consistent biologically significant compound-related effects in rats that received 60, 190, or 600 mg potassium picloram/kg/day for 14 days. In the subchronic study, rats received 60, 190, 600, or 1070 mg potassium picloram/kg/day in drinking water for 90 consecutive days. There were only 4 male and 2 female survivors out of 20 rats of each sex at the 1070 mg/kg dose and 16 male and 18 female survivors at the 600 mg/kg dose. Mortality was dose dependent. Administration of picloram appeared to exacerbate renal and hepatic lesions commonly noted in rats of this age. For example, at levels up to 1070 mg/kg mild lesions in the kidney of treated rats, especially in males at 600 mg/kg, were noted. Also noted were an increased incidence of mononuclear liver foci in male rats that received 190 and 600 mg/kg and an increased severity of mononuclear liver foci in females that received 600 mg/kg. There were no other consistent biologically significant compound-related effects. No specific organ site toxicity could be identified in these studies. Toxicity from exposure to picloram in drinking water is apparently low.