Study on the toxicity of methidathion

To study the acute and subchronic toxicity and mutagenicity of methidathion and find out its NEL. Experiments were carried out according to GB 15670-1995 "Methods of Toxicological Experiment on Pesticide Registration" and GB 15193-94. LD50 was 38.3 mg/kg in female mice and 31.6 mg/kg in male mice. The test on micronucleus and sperm shape abnormality in mice both showed negative. The subchronic test of methidathion showed significant inhibition on cholinesterase activity in the 11.67 mg/kg food group and 35.00 mg/kg food group. The food intake of the 35.00 mg/kg group significantly decreased. [Conclusion] The NEL of methidathion was (1.26±0.08) mg/(kg.d) for female mice and (0.40±0.04) mg/(kg.d) for male mice.