Ciência & Saúde Coletiva ISSN: 1413-8123 [email protected] Associação Brasileira de Pós-Graduação em Saúde Coletiva Brasil Saibrosa da Silva, Josiene; Gomes Moreno, Wallesk; Delano Soares Forte, Franklin; Correia Sampaio, Fábio Natural fluoride levels from public water supplies in Piauí State, Brazil Ciência & Saúde Coletiva, vol. 14, núm. 6, diciembre, 2009, pp. 2215-2220 Associação Brasileira de Pós-Graduação em Saúde Coletiva Rio de Janeiro, Brasil Disponível em: http://www.redalyc.org/articulo.oa?id=63012431028 Como citar este artigo Número completo Sistema de Informação Científica Mais artigos Rede de Revistas Científicas da América Latina, Caribe , Espanha e Portugal Home da revista no Redalyc Projeto acadêmico sem fins lucrativos desenvolvido no âmbito da iniciativa Acesso Aberto 2215 ARTIGO ARTICLE Natural fluoride levels from public water supplies in Piauí State, Brazil Concentração de flúor in natura em águas de abastecimento público no Piauí, Brasil Josiene Saibrosa da Silva 1 Wallesk Gomes Moreno 2 Franklin Delano Soares Forte 1 Fábio Correia Sampaio 1 Abstract The aim of this work was to determine Resumo O objetivo deste trabalho foi realizar um the natural fluoride concentrations in public levantamento dos teores residuais de flúor (F in water supplies in Piauí State, Brazil, in order to natura) da água de abastecimento em municípios identify cities in risk for high prevalence of dental do Piauí para identificar localidades com risco de fluorosis. For each city, two samples of drinking elevada prevalência de fluorose dentária. Para cada water were collected in the urban area: one from município, foram coletadas duas amostras da água the main public water supply and another from a de abastecimento da zona urbana, uma amostra public or residential tap from the same source. da principal fonte de abastecimento público do Fluoride analyses were carried out in duplicate município e a outra de uma torneira pública ou using a specific ion electrode and TISAB II. From residencial abastecida pela mesma fonte. As análi- a total of 222 cities in Piauí, 164 (73.8%) samples ses de flúor foram realizadas em duplicata, utili- were analyzed. Urban population in these towns zando um eletrodo específico e TISAB II. Dos 222 corresponds to 92.5% of the whole state with an municípios do Piauí, 164 (73,8%) enviaram amos- estimated population of 1,654,563 inhabitants tras para análise. A população urbana desses mu- from the total urban population (1,788,590 in- nicípios corresponde a 92,5% (1.654.536 habitan- habitants). A total of 151 cities showed low fluo- tes) da população urbana total do estado (1.788.590 ride levels (<0.30 mg/L) and 13 were just below habitantes). Observou-se que 151 municípios apre- optimum fluoride concentration in the drinking sentam baixos teores residuais de flúor (<0,30 mg/ water (0.31-0.59 mg/L). High natural fluoride L) e treze municípios apresentaram teores residu- concentration above 0.81 mg/L was not observed ais abaixo do nível ideal (0,31 – 0,59 mg/L). Ne- in any of the surveyed cities. As a conclusion, nhum município analisado apresentou teor resi- most of the cities in Piauí have low fluoride con- dual de flúor acima do aceitável (> 0,81 mg/L). centration in the drinking water. The risk for a Conclui-se que a maioria dos municípios do Piauí 1 Programa de Pós high prevalence of dental fluorosis in these urban possui água de abastecimento com baixos teores de Graduação em Odontologia areas due to natural fluoride in the water sup- flúor residual. O risco de uma elevada prevalência Mestrado em Odontologia plies is very unlikely. Thus, surveys about the den- de fluorose dentária pelo flúor residual da água de Preventiva e Infantil, UFPB. Campus I Cidade tal fluorosis prevalence in Piauí should be related abastecimento é pouco provável. Estudos sobre a Universitária with data about the consumption of fluoridated prevalência de fluorose dentária no Piauí devem 58051-900 João Pessoa PB. dentifrices and other fluoride sources. considerar outras fontes de flúor. [email protected] 2 Secretaria de Saúde do Key words Dental caries, Fluoridation, Surveil- Palavras-chave Cárie dentária, Fluoração das Piauí. lance, Dental fluorosis águas, Vigilância sanitária, Fluorose dentária 2216 et al. Silva JS Introduction Water samples collection and analysis In the Northeastern region of Brazil some inland cities from Paraíba and Ceará have moderate to high natural In each city at least two samples of the drink- fluoride levels (>1.0 mg/L) in the drinking water resulting ing water were collected. One sample was from in high prevalence of dental fluorosis and some severe the main public water supply and another from cases1-3. In Rio Grande do Norte, Paz et al.4 observed a public or residential tap from the same source. natural fluoride concentrations up to 1.1 ppm (mg/L), The Health Secretariat of the State of Piauí (SESA- and in such areas severe cases of dental fluorosis is likely to PI) informed to all local authorities about the occur due to high local temperatures and a high con- methodology of water samples collection. The sumption of rich fluoride drinking water. samples were collected by local sanitary vigilance It is estimated that in the Northeastern re- workers. Plastic recipients of 500 mL were dis- gion of Brazil only 16.5% of the cities have water tributed and they were requested to identify the fluoridation systems5. Therefore, the recent fed- samples (city, address, date of collection and eral program named “Brasil Sorridente” has giv- water source) in accordance to methods report- en the opportunity to implement water fluorida- ed by Funasa, 200417. Just after collection, the sam- tion systems in many cities of the Northeastern ples were transported by fast mail to the Labora- region where technical requirements for potable tory of Oral Biology at Federal University of water are accomplished6, 7 . Evaluation of the nat- Paraíba where the analyses were carried out. ural fluoride concentration in the drinking water All the samples were analyzed within 30 days is important since this information is relevant to after collection. The procedures were in duplicate establish the ideal concentration of fluoride in using a fluoride specific electrode (Orion model the drinking water in accordance to the mean 9609, Orion Research Inc., USA) coupled to an ion annual temperature8, 9 . analyzer meter (Orion model 710-A, Orion Re- The mean annual temperature in Piauí is search Inc., USA). The samples were analyzed in around 28ºC10 . Therefore, the optimal fluoride 1:1 with TISAB II. Calibration was frequently car- concentration in the drinking water is around 0.7 ried out with fresh fluoride standards of 1 mL of mg/L with accepted values between 0.6 and 0.8 0.2 up to 1.6 mg/L. The data in mV were trans- mg/L11. In Piauí, three cities have artificial water formed in µg of fluoride and in fluoride concen- fluoridation systems: Parnaíba, Floriano and Ter- tration (mg/L) using a Windows-Excel file. Only esina12, 13. The Parnaíba River is the only source of calibration curves with variation in percentage un- water for these cities and the residual fluoride con- til 5% for all standards and r³0.99 were accepted. centration is low14. However, the state of Piauí has The mean SD of the residual fluoride concen- a great deal of its territory placed in the semi-arid trations of each city was calculated from the two region where wells are the only source of drinking samples obtained. The mean SD of few cities was water available10. The probability of having high- calculated from three or four original samples due er fluoride concentrations in underground wa- to different water sources in the same urban area. ters than in surface waters has already been ob- The data were classified according to the fluoride served in many parts of the world including in the concentration in mg/L in four groups: 1) from 0.01 Northeast region of Brazil3,15. Thus, the aim of to 0.30 mg/L (very low F concentration); 2) from this study was to determine the natural fluoride 0.31 to 0.59 mg/L (low F concentration); 3) from concentration in public water supplies in Piauí 0.60 to 0.80 mg/L (optimum F concentration) and State, Brazil, in order to identify cities at risk for 4) above 0.81 mg/L (high F concentration). high prevalence of dental fluorosis. Results Methods From 222 towns in Piauí, 164 (73.8%) samples Areas under study were sent for fluoride analyses. Based on the es- timates of IBGE, 200016, the urban population of The state of Piauí has 222 cities and an esti- all these cities corresponds to 92.5% (1,654,536 mated population of 2,843,278 inhabitants16. It is inhabitants) from the total urban population in also estimated that 63% lives in urban areas Piauí (1,788,590 inhabitants). (1,788,590 inhabitants). The annual average tem- In Table 1, it is observed that 151 cities pre- perature in Piauí is high and around 28ºC in most sented very low natural F concentration, where- part of its territory10. as 13 showed low natural F concentration. 2217 Ciência & Saúde Coletiva, 14(6):2215-2220, 2009 Table 2 shows that the 13 cities with low nat- tions9, 17. The set up of two samples of the main ural F concentrations in the drinking water are water source from urban areas was established in small cities covering approximately 80,000 in- due to fact that in few cities of Piauí a record of habitants. more than one source of water could take place Table 3 lists all cities according to their distri- particular during drought periods19.