HC Deb 05 March 1985 vol 74 cc513-4W
Mr. Best

asked the Secretary of State for Social Services what is the nature and extent of the danger of overdose, and the degree of mottling of the teeth, which can arise when the level of fluoride in the water supply is twice the maximum recommended; what scientific evidence is available to him as to the concentration of fluoride in the water supply at which a risk of fatal poisoning may arise; and if he will make a statement.

Mr. John Patten

There is evidence from the United States of America that, where the level of fluoride naturally present in the water supply is around two parts per million, an increasing proportion of children have mottled enamel that is apparent and objectionable aesthetically (Dean H. T. and Elvove E "Further studies on the minimal threshold of chronic endemic dental fluorosis" (Public Health Report 52: 1249–64 September 10 1937)). The ingestion of water containing a concentration of fluoride of 2 ppm, in a temperate climate, has, however, no harmful effect upon general health. This has been established by studies of communities in the USA and in this country where the drinking water contains fluoride in high natural concentrations (for example, Leone et al, Public Health Reports69 925 (1954); Heasman and Martin, Monthly Bulletin of the Ministry of Health 21 150–160 (1962)).

With regard to the risk of fatal poisoning, the Registry of Toxic Effects of Chemical Substances (1981–82) reports the lowest lethal dose of sodium fluoride in man to be 71 mg per kg body weight, corresponding to a dose of 2240 mg of fluoride ion in a 70 kg adult. In order for this quantity to be ingested in the normal volume of water drunk in 24 hours, the concentration of fluoride in water would need to be greater than 2000 parts per million.

Mr. Best

asked the Secretary of State for Social Services if he will list all those community health councils in England which have expressed opposition to fluoridation of water supplies.

Mr. John Patten

Information on the views of community health councils regarding fluoridation is not held centrally.

Mr. Best

asked the Secretary of State for Social Services what study he has made of the findings of Edwards, Pantos and Kraut on the effect of fluoride on hydrogen bonding in cyclochrome-C peroxidase inhibited with fluoride; what are the implications of this research for his assessment of the safety of fluoridating water at one part per million; and if he will make a statement.

Mr. John Patten

[pursuant to his reply, 4 March 1985]: The study of Edwards, Pantos and Kraut published in the "Journal of Biological Chemistry" in 1984 (volume 259) does not in any way alter the assessment of the safety and efficacy of the fluoridation of water to one part per million. It has been known for many decades that fluoride at high non-physiological concentrations can inhibit or enhance the action of many enzymes. There is however, no evidence of enzyme inhibition in humans from the consumption of water fluoridated to one part per million and no evidence of any specific harmful effect which could be attributed to inhibition of enzymes in this manner.

Mr. Best

asked the Secretary of State for Social Services why he has hitherto indemnified statutory water undertakers which fluoridate water supplies.

Mr. John Patten

[pursuant to his reply, 4 March 1985]: The indemnity offered in respect of fluoridation schemes covers essentially costs waived in respect of claims that fluoridation is either illegal or injurious to health. No such claim has ever been made successfully in England. The indemnity is offered to assist statutory water undertakers who wish to accede to requests from health authorities to implement fluoridation schemes. This is in keeping with the policy of successive administrations to encourge fluoridation, whilst leaving the decision on whether or not to fluoridate to be taken entirely at local level.