Letter: Water chemicals

Sir: Dr Adrian Padfield (letter, 16 January) shows admirable concern for his patients but he is sadly mistaken when he refers to dental caries being "easily prevented by simple water management, as with the reduction of bacterial disease".

I have been involved, as an engineer, with the treatment of water for public supply for thirty years and know only too well the range of quite unpleasant chemicals which are used in that process, including chlorine to kill bacteria, ozone to destroy potential carcinogens and phosphoric acid to prevent dissolution of lead.

These chemicals are used to render the final product safe to drink. Fluoride is the only chemical currently added to water supplies for the sole purpose of medication or prophylaxis. This is a most important distinction. Worthy though it may be to reduce dental caries, compulsory mass medication via water supply is the thin end of a very dangerous political wedge and should, I believe, be strenuously resisted.

Millions of tons of water are treated every day, only a tiny fraction of which is ingested. If, as Dr Padfield clearly believes, there should be some form of compulsory mass medication, then let it be by the compulsory addition of fluoride to all toothpastes. This would not only be more efficient in treating the disease but would, I suspect, be rather more cost-effective.

RICHARD HILL

Penn, Buckinghamshire