Toxicity of endosulfan and manganese chloride: cumulative toxicity rating

There has been, in general, no accepted comparable way to express the effects of repeated doses. This study was designed to provide information on cumulative toxicity of manganese chloride (MnCl2), endosulfan, and a mixture of these compounds and to suggest cumulative toxicity rating. Male mice were given the test compound i.p. 6 days/week for a minimum for 10 weeks and until the cumulative LD50 remained constant for 3 consecutive weeks. Using a ratio between a single dose and weekly cumulative LD50 (CLD50), cumulative toxic factors (CTF) were determined. The CTF for weeks 1-13 for MnCl2 ranged from 0 to 3.48; endosulfan LD50 and CLD50 values for a mixture of MnCl2 and endosulfan were higher than the expected values, indicating a greatly reduced toxicity of a mixture, when given either in a single dose or repeated doses. Using the CLD50 criterion as laid down in this study, the cumulative toxicity rating, class 1 to 6, has been suggested so as to have a comparative assessment of th cumulative potential of several compounds.