The comparative cytogenetic effects of aldrin and phosphamidon

An organochlorinated pesticide (aldrin) and an organophosphorus one (phosphamidon) were administered in human lymphocyte cultures, and the cytogenetic effects were related to the compound concentration. The comparative estimation of the number and type of chromosome aberrations observed in the treatments with various doses of drugs permits the following statements. (a) The aldrin showed a narrow range of clastogenic doses, between 19.125 and 38.25 mug/ml. Since these doses are near the limit for cell survival, the observed chromosome lesions are probably not perpetuated in other abnormal cells. (b) Comparatively, the range of phosphamidon clastogenic doses is very large, scattered between 1.9 and 122 mug/ml. Since, in the phosphamidon treatments, the cellular death begins at a concentration above 244 mug/ml, the chromosome aberrations, induced especially by the low doses, could be maintained in other abnormal cells. In a smaller number of experiments, chromosome examinations were performed after intraperitoneal injections of the drugs into rats and mice, 24 h before harvesting of the bone marrow. The administered doses were low, as compared with those of the experiments in vitro: the minimal doses inducing chromosome aberrations in vivo were, in the aldrin treatments 9.56, and in the phosphamidon treatments, 0.07 mug/g body weight. In the experiments both in vitro and in vivo, the analysis of the frequencies of the abnormal cells and of the chromosome lesion types support the existence of a dose-response correlation. The genetic peril due to low doses of pesticides with a general weak toxic effect is discussed.