Chemical changes of organic compounds in chlorinated water. XVII. Production of mutagens in reactions of naphthalene compounds with hypochlorite in aqueous solution.

Abstract

The reaction products of naphthalene and its methyl derivatives (1- and 2-methyl-, 1, 2-, 1, 3-, 1, 4-, 1, 5-, 1, 8-, 2, 3- and 2, 6-dimethyl-, and 2, 3, 5-trimethyl substituents) with hypochlorite in water were determined by means of gas chromatography, and were tested for mutagenicity on Salmonella typhimurium TA98 and TA100. Naphthalene compounds were shown to produce a variety of chlorination products, including chloro-substituted, oxygenated, and hydroxylated compounds, in chlorinated water. None of these compounds before chlorination was mutagenic to the tester strains TA98 and TA100 with or without the rat hepatic S9 mix. However, treatment with hypochlorite of naphthalene, 1- and 2-methylnaphthalenes, 1, 3- and 2, 6-dimethylnaphthalenes, and 2, 3, 5-trimethylnaphthalene in water was shown to produce mutagens in strain TA98 without S9 mix. Several samples obtained from the chlorinated 2-methylnaphthalene, 1, 5- and 1, 8-dimethylnaphthalene, and 2, 3, 5-trimethylnaphthalene solutions also exhibited mutagenic activity on strain TA98 with S9 mix. The production of mutagenic substances was dependent on the reaction pH, the reaction time, and the chlorine dose. The significance of these findings for water chlorination systems is discussed.