title: Natural fluoride levels in the drinking water, water fluoridation and estimated risk of dental fluorosis in a tropical region of Brazil.
abstract: OBJECTIVE
  The aim of the present study was to determine the natural fluoride levels in the drinking water supplies of a tropical area of Brazil to identify the cities at risk of high prevalence of dental fluorosis and to provide data for future water fluoridation projects in the region.
  
  
  METHODS
  The present study was carried out in Paraíba, in the north-eastern region of Brazil. A total of 223 cities were selected, and local health workers were instructed to collect three samples of drinking water: one from the main public water supply and the other two from a public or residential tap with the same water source. Fluoride analyses were carried out in duplicate using a fluoride-specific electrode coupled to an ion analyser.
  
  
  RESULTS
  A total of 167 cities (75%) provided water samples for analysis. Fluoride levels ranged from 0.1 to 1.0 ppm (mg/l). Samples from most of the cities (n = 163, 73%) presented low levels of fluoride (< 0.5 mg/l). Samples from three cities (a total estimate of 28,222 inhabitants exposed) presented 'optimum' fluoride levels (0.6 to 0.8 mg/l). Samples from one city (16,724 inhabitants) with 1.0 mg/l of fluoride in the water were above the recommended level (0.7 mg/l) for the local temperature.
  
  
  CONCLUSIONS
  It can be concluded that the cities in this area of Brazil presented low natural fluoride levels in the drinking water and could implement controlled water fluoridation projects when technical requirements are accomplished. A high or a moderate prevalence of dental fluorosis due to the intake of natural fluoride in the drinking water is likely to take place in one city only.
authors.affiliation: Postgraduate Program in Preventive Dentistry and Pedodontics, Federal University of Paraiba, Campus I, Castelo Branco, 50851-900, Joao Pessosa, Brazil. fabios@ccs.ufpb.br
authors.forename: Fábio Correia
authors.initials: FC
authors.lastname: Sampaio
authors.forename: Fábia Danielle
authors.initials: FD
authors.lastname: Silva
authors.forename: Andréa Cristina
authors.initials: AC
authors.lastname: Silva
authors.forename: Ana Thereza
authors.initials: AT
authors.lastname: Machado
authors.forename: Demétrius Antônio
authors.initials: DA
authors.lastname: de Araújo
authors.forename: Erik Melo
authors.initials: EM
authors.lastname: de Sousa
mesh_terms: D001938:Brazil / Q000453:epidemiology; D005457:Fluoridation / Q000009:adverse effects; D005459:Fluorides / Q000032:analysis*; D009050:Fluorosis, Dental / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D015995:Prevalence; D012306:Risk; D014329:Tropical Climate; D014505:Urban Population; D014881:Water Supply / Q000032:analysis*
chemical_list: D005459:Fluorides