Long-term toxicity of octachlorostyrene in the rat.

This study was designed to investigate the toxic effects produced by the long-term exposure to octachlorostyrene (OCS), a demonstrated environmental contaminant in the Great Lakes region of North America and the Norwegian Coast in Europe. Groups of 20 male and 20 female rats were administered OCS in diets at 0.005, 0.05, 0.5, 5.0, or 50 ppm for 12 months. Weight gain and food consumption were not affected. Increased liver weights were observed in the groups fed the highest dose of OCS. Hepatic microsomal aniline hydroxylase and aminopyrine demethylase activities were induced in male rats fed 5.0 ppm OCS and higher and in female rats fed 50 ppm of the chemical. Elevated serum cholesterol levels were seen in rats of both sexes fed the highest dose. Treatment-related histological changes occurred in the thyroid, liver, and kidney of rats. A dose-dependent accumulation of OCS in the fat and liver of the rats was found. Based on the data presented, it was concluded that the no adverse effect level of OCS was 0.5 ppm.