The effect of dimethoate, dichlorvos, and parathion-methyl on bone marrow cell chromosomes of rats in subchronic experiments in vivo.

The three organophosphorous insecticides dimethoate, dichlorvos, and parathion-methyl were investigated in subchronic experiments on bone marrow cell chromosomes. In the literature these compounds were reported to exhibit both positive and negative results in mutagenicity tests demanding further investigations in subchronic tests. The treatment of different groups of male Wistar rats lasted for 6 weeks with 5 treatment days per week at doses of 1/100, 1/75, and 1/50 of the LD50. Following the last treatment, bone marrow cell chromosomes were prepared. The frequency of cells revealing any aberrations as well as numeric and structural aberrations were evaluated. In this test both dimethoate and dichlorvos demonstrated mutagenic effects following subchronic treatment of Wistar rats, while parathion-methyl at doses of 1/100, 1/75, and 1/50 of LD50 displayed no significant mutagenicity.