Biochemical interactions of chlorine dioxide and its metabolites in rats.

Abstract

The problems arising from trihalomethanes formation resulting from the inadvertent reactivity of chlorine with organic compounds contained in water supplies suggest an alternative to chlorine may be desirable. Chlorine dioxide (ClO2), which does not form trihalomethanes, is being considered as a very attractive alternative disinfectant. The study was conducted to examine the effect of ClO2 and its metabolites on the formation of chloroform,3H-thymidine incorporation in organs, and hepatic microsomal enzyme activities in rats. Male rats were administered 0, 10, 100 mg/L ClO2 or 1, 10 mg/L of ClO 2 - or ClO 3 - daily for one year in the drinking water. Blood chloroform levels were significantly decreased in the ClO2 groups at 2, 10 and 12 months treatment. Chlorite and chlorate groups show similar decreases in blood chloroform concentration after one year. However, no significant chloroform values in liver, kidney, spleen, testes, and brain were observed in any treatment groups at the same time period. Chlorine dioxide (5 mg/L) inhibits the formation of chloroform by HOCl (5, 10, 20 mg/L) and sodium citrate (1 mM) and the degree of inhibition depends on the ratio of ClO2/ HOCl. ClO2 and ClO 2 - administered in drinking water for three weeks inhibited the incorporation of3H-thymidine into nuclei of rat testes and small intestine. The incorporation in the liver was increased in both 10 and 100 mg/L ClO2 groups. Hepatic enzyme assays revealed that aniline hydroxylase activity was significantly increased in the 100 mg/L ClO2 group and hexobarbital sleep time studies showed slight decreases in the ClO2 treatment groups after one year treatment.