Toxicity of Chlorine Dioxide in Drinking Water

Abstract
Chlorine dioxide (CIO2) is currently being considered as an alternate to chlorine as a disinfectant for public water supplies. Studies were conducted to determine the toxicity of CIO2 (0, 1, 10, 100, 1000 mg/L) and its metabolites, CIO-2 and CIO-3 (10, 100 mg/L) in drinking water in rats. After 9 months treatment the osmotic fragility of the red blood cells was decreased in all treatment groups, while a decreased blood glutathione was only observed in the metabolite groups. At 2, 4, and 6 months no significant hematologic changes were noted in treated rats compared to control. However, after 9 months RBC counts, hematocrit, and hemoglobin were decreased in all treatment groups. CIO2, CIO-2, and CIO-3 administered chronically in drinking water for 3 months inhibited the incorporation of 3H-thymidine into nuclei of rat testes. This inhibition was observed in the liver of CIO-2 groups and in the kidney of 100 mg/L CIO2 treatment. The incorporation in small intestinal nuclei was increased in both 10 and 100 mg/L CIO2 and in 10 mg/L CIO-2. The treatment with CI compounds decreased rat body weight in all groups after 10 and 11 months treatment.