Abstract
The mutagenic extract of chlorinated tap water was subjected to HPLC fractionation. About 19,000l of chlorinated tap water was concentrated by XAD-4 absorption in pH 2, followed by the elution by dichloromethane. This concentrate was divided into acidic and neutral fractions. Each fraction was subjected to ODS-reversed phase HPLC fractionation. HPLC subfractions of each fraction were assayed for mutagenicity and analyzed for the strong mutagen, 3-chloro-4-dichloromethy-5-hydroxy-2(5H)-furanone (MX). Only two of nine HPLC subfractions from the acidic fraction showed significant mutagenicity, and one subfraction contained MX, which explained 55% mutagenicity of that subtraction. Another mutagenic subfraction did not contain MX. Unknown mutagens in these subfractions were presumed to have similarities to MX in their structures or chemical natures.
HPLC fractionation of neutral fraction resulted in many mutagenic subfractions. This implies that the neutral fraction contained many mutagens, which might not be similar to MX. Mutagens in this fraction have more unknown nature than the acidic fraction.
Reactivity of the mutagens and sulfite was also studied. About 60% of the mutagenicity of the tap water was destroyed after 6.5h reaction with sulfite in 1.5 chlorine equivalent concentration. 28h reaction with sulfite in 5.0 chorine equivalent concentration destroyed 76% mutagens.
