The application of bacterial mutagenicity tests to drinking water has shown the presence of mutagens. Invariably, mutagens generated during water treatment chlorination account for much of the mutagenicity detected in most surface-water-derived drinking waters. These mutagens are formed from widespread, naturally occurring precursors, such as humic substances, although other substances, especially amino acids may be involved. Most of the chlorination-derived mutagens identified account for little of the mutagenicity of drinking water. However, one mutagen, MX, is highly potent and may have a significant contribution. Its occurrence and toxicity need full evaluation. Other oxidants/disinfectants, such as ozone and chlorine dioxide, can also generate mutagens but these are likely to differ from those produced by chlorination. Granular activated carbon is effective in removing chlorination-derived mutagens but less effective for precursors. Dechlorinating agents, such as sulphur dioxide, can eliminate some of the mutagens produced by chlorination. The bacterial mutagenicity test cannot give information on the actual risks to health posed by the mutagens. Such information could arise from follow up work on identified major mutagens and from application of other bioassays more indicative of effects in man. Consequently, at the present time it is difficult to justify major changes to treatment practice aimed solely at controlling mutagenicity.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- The Formation and Removal of Chemical Mutagens During Drinking Water Treatment
- Springer Netherlands
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