DR Andrew Mortimore of Southampton City Primary Care Trust (letters, April 26) tried to persuade readers that the fluoride chemical should be added to local tap water supplies.

It sounds reassuring when he claims that adding this chemical is the same as the fluoride which is present in some water supplies.

However, natural fluoride is calcium fluoride, which is very different to the artificial chemical waste added in fluoridation schemes. The type added is fluorosilicic acid waste from phosphate fertilizer factory chimney scrubbers, which is contaminated with toxic arsenic, lead & mercury from industry.

The amount added in artificial fluoridation schemes is ten times higher than is present naturally in some water.

Even the American Dental Association's (ADA) website advised that fluoride-free fluoride bottled water should be used to make up babies' bottles to prevent babies receiving too much fluoride. The ADA recommend that no fluoride be given to children under a year old. That speaks for itself!

A WILLS, Ruislip, Middlesex.