STUDIES ON CHRONIC TOXICITY OF THE LOW LEVELS OF O, O-DIMETHYL O-(3-METHYL-4-NITROPHENYL) PHOSPHOROTHIONATE (SUMITHION) IN THE RAT

Abstract

To observe the chronic toxicity of Sumithion (o, o-dimethyl, o-(3-methyl-4-nitrophenyl) phosphorothionate), 8 groups of male and female rats were fed for one year with control food and food containing 1, 5 and 25 ppm of the compound. Acute toxicity was also done. We obtained the following results ; 1. Oral and intraperitoneal _&lt50&gt of male rats were 250 and 500 mg/kg and those of female rats were 310 and 500 mg/kg respectively. All rats showed neurotropic symptoms according to dose. 2. There was no significant difference in body weights, food and water intakes for one year experiment at those dose levels. Some pneumonitis was observed by histological findings in experimental groups at the end of the experiment. 4. Acetylcholinesterase activity of brain, liver and red blood cells were slightly decreased in the first month after feeding, but it recovered and kept normal level until the end of experiment.