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| Environmental aspects of water fluoridation |
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| Introduction |
Fluorine is one of the most electronegative of all chemical elements and is so reactive that it is rarely encountered in nature in the elemental form. Combined chemically in the form of fluorides, fluorine is abundant in the earth's crust. It is not surprising therefore that fluoride is found in seawater, fresh water, mineral deposits of fluorspar, cryolite, fluorapatite, and in surface dusts found close to a few of the mineral deposits (World Health Organisation 1970). The principle sources of supply of fluoride available to the physiology of man are: |
- water;
- some types of vegetation, including tea leaves;
- some seafoods;
- dust in certain parts of the world; and,
- certain industrial processes.
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| The environmental impact of fluorides has been well documented since at least 1937. |
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| Recent reviews |
More recent reviews of the environmental impact of fluorides include:
The World Health Organisation
The World Health Organisation (WHO) has reviewed the literature (World Health Organisation 1970; Expert Committee on Oral Health Status and Fluoride Use 1994) and identifies the principal sources of fluoride pollution as industries and mining. WHO notes that in the absence of adequate emission control in such settings environmental pollution can be a problem. Such pollution has been a problem in the past in industrialised countries, and WHO warns that unless proper environmental safeguards are adhered to, there is a danger of it occurring in developing countries with increasing industrialisation. Fluoride pollution is therefore recognised by WHO as an industrial hazard; however WHO does not consider water fluoridation a potential source of fluoride pollution.
Royal College of Physicians
The Royal College of Physicians reviewed the literature in 1976 and concluded "fluoridation does not harm the environment". (Royal College of Physicians 1976).
Osterman, McGill University Montreal, 1990
Focusing on the effects of fluoridation on aquatic environment, Osteman's investigation evaluated the impact of water fluoridation on the aquatic environment, and found that "fluoridated water loss during use, dilution of sewage by rain and groundwater infiltrate, fluoride removal during secondary sewage treatment, and diffusion dynamics at effluent outfall, combine to eliminate fluoridation related environmental effects." (Osterman 1990) In the US, where well over 60% of water supplies are fluoridated, Osterman found the fluoride concentration in most rivers averaged 0.33ppm. A literature review by Osterman did not reveal any examples of municipal water fluoridation causing recommended environmental concentrations to be exceeded, although excesses occurred in several cases of severe industrial water pollution not related to water fluoridation.
Environment Agency and the Scotland and Northern Ireland Forum for Environmental Research
An environmental risk assessment conducted for the Environment Agency and the Scotland and Northern Ireland forum for Environmental Research comprehensively reviewed the aquatic toxicity of fluoride and proposed environmental quality standard (EQs) for fluoride (Dixon et al. 2000). In personal communication, one of the report's authors (Wendy Young 18 August 1999) said "on the basis that water systems are fluoridated at 1mg1-1, the theoretical maximum in wastewater effluent (before dilution) could potentially be 1 mg 1-1 this is in line with EQS value for surface water. (The fluoride content of seawater is fairly constant at levels between 1.2 - 1.4 mg/l which is higher than the theoretical maximum in wastewater effluent). |
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| Safety at the water treatment works |
Worldwide there are thousands of fluoridation schemes in operation - the earliest dating from 1945. Water suppliers have therefore accumulated a wealth of practical experience in managing the fluoridation process safely and efficiently.
In the UK strict operational criteria are laid down in the Department of the Environment Code of Practice on Technical Aspects of Fluoridation of Water Supplies (Department of the Environment 1987). These are designed to ensure that:
- the mean fluoride content of the water leaving the works in a calendar month is maintained between 0.9 and 1.1 parts per million, calculated for those periods when the fluoridation plant is in operation;
- the fluoride content of the water leaving the works is maintained between 0.8 and 1.2 parts per million for at least 90% of the time when the fluoridation plant is in operation;
- the fluoride content of the water leaving the works shall not exceed 1.5 parts per million at any time.
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| Summary |
There appears to be no concern about the environmental aspects of water fluoridation among those experts who have investigated the subject. Furthermore, since the chemicals used for water fluoridation are co-products of the manufacture of phosphate fertilisers, and the raw material used is a natural resource (rocks excavated for their mineral content), water fluoridation could accurately be described as environmentally friendly as it maximises the use made of these natural resources, and reduces waste. (See information on the manufacture of chemicals for water fluoridation in the Technical Aspects section of this website.) |
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| References |
- Department of the Environment. (1987): Code of Practice on Technical Aspects of Fluoridation of Water Supplies. London: HMSO.
- Dixon, E., Sutton, A., and Young, W. (2000): Proposed Environmental Quality Standards for fluoride in water. WRc R&D Technical Report P99. Bristol: Environment Agency.
- Expert Committee on Oral Health Status and Fluoride Use. (1994): Fluorides and oral health. WHO Technical Report Series No. 846. Geneva: World Health Organisation.
- Osterman, J. W. (1990): Evaluating the impact of municipal water fluoridation on the aquatic environment. American Journal of Public Health 80, 1230-1235.
- Royal College of Physicians. (1976): Fluoride Teeth and Health. Bath: Pitman Medical.
- World Health Organisation. (1970): Fluorides and human health. Geneva: World Health Organisation Monograph Series No 59.
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