Nonvolatile Mutagens in Drinking Water: Production by Chlorination and Destruction by Sulfite

Abstract

In concentrates of water produced in a laboratory simulation of a drinking water treatment process, direct-acting, nonvolatile mutagens were readily detected by means of the Ames Salmonella test. The mutagens were shown to be produced by the chlorination process. Treatment of the water with chloramine resulted in less mutagenic activity than treatment with free chlorine. Dechlorination of drinking water with sulfite sharply reduced the mutagenic activity. Treatment with sulfur dioxide is proposed as an effective, inexpensive method of reducing the direct-acting mutagenic activity of drinking water and of aqueous industrial effluents.

3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and mutagenic activity in Massachusetts drinking water.

“…The choice of disinfectant greatly influences the type and amount of byproducts that are formed. Chloramination (40), ozonation (41), and a combination of the two (39,42) have been shown to result in reduced mutagenic activity. Alternative disinfectants result in fewer trihalomethanes (43) but produce additional by-products.…”

Reproductive Toxicology of Disinfection By-Products

“…The need to investigate the potential reproductive hazard associated with chlorination ofthese substances arises from their known genotoxic properties (4)(5)(6), and form the enormous exposed population associated with potable water supplies. The validation of model humic compounds as a substitute for naturally concentrated material has made laboratory studies feasible.…”

“…Some of the major classes of compounds generated from humics during the disinfection process, for example, the trihalomethanes (1,2) and chlorophenols (3), have, for some time, been an established focus ofconcern in drinking water health studies. More recently, attention has centered on the mutagenic activity associated with water chlorination (4)(5)(6). The chemicals responsible for this activity have been difficult to identify because they are present in a complex mixture and in minute quantities.…”

Drinking Water and Cancer: Review of Recent Epidemiological Findings and Assessment of Risks

“…This concentrate was not mutagenic for bacterial cells but was mutagenic for mammalian cells and induced cellular transformation in human embryonic lung fibroblasts. Cheh et al (33) formed concentrates of water produced in a laboratory simulation of a drinking water treatment process and tested the concentrates for mutagenicity in bacterial cells. Nonvolatile mutagens were produced by chlorination and could be destroyed by treatment with sulfur dioxide.…”