RESEARCH – January 2007

Human exposure to fluorides via drinking water in Estonia


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Drinking water comes mainly from several groundwater aquifers; only two cities (capital Tallinn and Narva) use surface water as a source of drinking water. Overall access to water supplies is 82.9%.
The aim of the study was to determine fluoride content in drinking water in different regions of Estonia, to assess population exposure to fluoride, to recommend measures to optimise it and to prevent possible health risks.
Subjects and methods. Fluoride content in drinking water was analysed in 735 samples from the public water supplies of 47 towns and 471 rural settlements in all 15 counties throughout Estonia.
Results. The results indicate that the content of fluoride in drinking water ranged from 0.01 to 6.95 mg/l. Concentrations exceeding the permissible limit (1.5 mg/l) were obtained in 14.4% of the samples. A great majority  (over 95%) of Estonian population is drinking water with fluoride content below maximum permitted level. Conditions are unfavorable for 42 600 (4.1%) inhabitants, first of all in Western Estonia, who consume high-fluoride drinking water and are exposed to toxic effects of fluoride. This problem concerns mainly small public water supplies. High-fluoride drinking water originates from Ordovician and Silurian aquifers. Over half of the population (57.8%) consumes low-fluoride drinking water and are deprived of the beneficial effects of fluoride on the teeth through hardening of the enamel and reducing the risk of dental caries.
Conclusion. Fluoride levels in water have to be taken into account when planning and implementing public water supply projects. Preventive measures to reduce adverse health effects associated with different fluoride level in drinking water are discussed.