Fluoretação da água dos dez maiores municípios do estado do Tocantins, Brasil / Water fluoridation in the ten largest municipalities of the state of Tocantins, Brazil

Resumo Fluoretação da água é uma estratégia de controle da cárie, recomendada pela OMS. No Brasil ela é regulamentada por lei, mas não tem sido implementada com sucesso na região Norte. Os objetivos desta pesquisa foram levantar dados sobre a existência do heterocontrole nos 10 maiores municípios tocantinenses e analisar a concentração de fluoreto presente na água de abastecimento público destas cidades. A pesquisa foi realizada de maio-agosto/17 e teve como marco teórico-metodológico a análise quantitativa, descritiva e transversal. Coletas de água foram realizadas mensalmente, utilizando protocolo de amostragem de coleta de água da rede. A concentração de fluoreto nas águas foi feita com eletrodo íon específico pela técnica direta. Constatou-se que a vigilância da fluoretação da água está em operação na capital do estado desde 2016. Com relação a concentração de fluoreto na água, foi encontrado que 31,6% das amostras analisadas estavam adequadas para o máximo benefício de redução de cárie e 27,5% delas apresentavam risco alto ou muito alto de fluorose dentária. É necessário implementar um programa de controle da concentração de flúor na água no Tocantins, a fim de garantir que a população não seja privada dos benefícios anticárie da agregação de flúor à agua tratada.

Abstract Water fluoridation is a strategy for caries control recommended by the WHO. In Brazil, it is regulated by law but this program has not been successfully implemented in the North region. This research aimed to collect data on the existence of external control (heterocontrol) in the ten largest municipalities in the state of Tocantins, Brazil, and to analyze fluoride concentration in the public water supply of these cities. The study was conducted from May-August/17, and its theoretical-methodological framework was a quantitative, descriptive and cross-sectional analysis. Water collections were carried out monthly, using sampling protocol of water collection of the network. Fluoride concentration in the waters was determined with ion specific electrode by the direct technique. It was verified that water fluoridation monitoring is only been done in Palmas, capital of the state, starting in 2016. Thirty-two percent of waters samples analyzed showed fluoride concentration to obtain the maximum benefit of reduction caries and 27.5% of them presented a high or very high risk of dental fluorosis. It is necessary to implement a program to control the concentration of fluoride in the water of the municipalities of Tocantins, in order to ensure that the population is not deprived of the anticaries' benefits of the adjustment of fluoride concentration of the treated water.

Análise microbiológica da água em escolas públicas de Marabá, Pará / Microbiological analysis of water in public schools in Marabá, Pará

Objetivo: analisar a qualidade microbiológica da água de cinco escolas públicas da cidade de Marabá-PA e correlacionar com possíveis fatores de desigualdades sociais em saúde no entorno dessas escolas. Metodologia: as análises microbiológicas foram realizadas em cinco escolas públicas no interior do Pará, usando a técnica do número mais provável, associado a registro das características do entorno das escolas. O teste T Student foi utilizado para verificar as diferenças entre os resultados microbiológicos da água entre as escolas em que houve contaminação e também para testar as diferenças entre a vulnerabilidade socioambiental urbana no entorno das escolas e a contaminação da água. Resultados: observaram-se diferenças estatisticamente significantes entre as escolas E3 e E5 no teste para coliformes totais (p=0,043) e termotolerantes (p=0,008). A partir das condições de vulnerabilidade socioambiental urbana no entorno a escolas, encontrou-se diferenças estatisticamente significativas entre as escolas apenas em relação às condições de saneamento (p=0,05). Considerações Finais: as condições microbiológicas da água utilizada em duas escolas são insatisfatórias, o que indica risco à saúde para alunos, professores e funcionários das escolas.

Objective: to analyze the microbiological quality of water in five public schools in the city of Marabá-PA and to correlate with possible factors of social inequalities in health around these schools. Methodology: the analysis of the microbiological water quality was carried out in five schools in the interior of Pará, using the most likely number technique, associated with recording the characteristics of the schools' surroundings. We used Student T test to verify the differences between the microbiological results of water between the schools where there was contamination and to test the differences between the urban socio-environmental vulnerability around the schools and the water contamination. Results: statistically significant differences were observed between schools E3 and E5 in the test for total coliforms (p=0.043) and thermotolerants (p=0.008). We found statistically significant differences were found between schools only in relation to sanitation conditions (p=0.05). Final Considerations: the microbiological conditions of the water used in two schools are unsatisfactory, which indicates a health risk for students, teachers and school team.

Solid-phase Extraction for Analysis of Short-chain Chlorinated Paraffins in Water Samples / 分析化学

A method for short-chain chlorinated paraffins ( SCCPs) analysis in water samples based on solid-phase extraction ( SPE ) was developed using gas chromatography coupled with electron capture negative chemical ionization mass spectrometry ( GC-ENCI-MS) . SPE parameters including the sorbent, elution solvent and elution volume were optimized. Agilent Bond Elut-C18was precleaned with 3 mL of hexane, 3 mL of methanol and conditioned with 3 mL of H2O before use. After enriched by the cartridge, the sample was washed by 3 mL of methanol (10% , V/V) and eluted by 3 mL of mixture of hexane and dichloromethane (1∶1, V/V). The results showed that the limits of detection ( LOD) of SCCPs were 18 ng/L, and the corresponding limits of quantitation of SCCPs were 60 ng/L. Recovery experiment showed that, for the water samples spiked with 1 μg/L, the recoveries were in the range of 90% -135% and the relative standard deviations were less than ±10% . Finally, the SCCPs in 20 surficial water samples collected in Beijing were analyzed using the method proposed here. The range of the concentrations of SCCPs was ＜LOD to 682 ng/L with a mean concentration of 216 ng/L.

Evaluation on the design and application effect of pure water analysis system of medical proton and heavy ion accelerator / 中国医学装备

Objective: To design an online pure water analysis system based on the proton and heavy ion accelerator (IONTRIS system) in Shanghai proton and heavy ion center (SPHIC), and to evaluate its application effect by operating data statistics. Methods: The system used the control system of Siemens S7-300 PLC to collect online data from sensors of pure water system. Analyzing the operation rules and setting the limiting value of alarm, and using WINCC software to develop monitoring and analysis system of central computer so as to real-time operate online data. The application effect of the system was evaluated by comparing the cost of one month consumables between before and after the system was applied. Results: After the system was applied, the real-time monitoring of pure water system was realized, and the efficiency of the consumables was enhanced. Conclusion: The application of the pure water analysis system has a good effect on the operation efficiency of the pure water system.

Determinación de la dureza total en agua con EDTA empleando una solución amortiguadora inodora de borato / Total hardness water determination by EDTA using a olorless buffer borate

La determinación de Dureza Total con EDTA en agua usando una solución amortiguadora de amonio pH 10 tiene la desventaja de generar vapores de gas amoníaco que suelen ser molestos o ser potencialmente dañinos para el sistema respiratorio del operario. El objetivo de este estudio fue utilizar una solución amortiguadora inodora de borato pH 10 en sustitución de una solución amortiguadora de amonio a pH 10 para la determinación de la dureza total en agua por la metodología de la norma COVENIN 2408-86 y determinar si existía diferencia estadísticamente significativa entre ambos procedimientos. Se determinó la Dureza Total usando la solución amortiguadora inodora de borato en 13 muestras de agua con diferentes grados de dureza (suave, dura y muy dura); los resultados obtenidos se compararon con los valores del procedimiento de referencia. La solución amortiguadora permitió una visualización rápida y definida del punto final durante la ejecución de la determinación volumétrica, los resultados mostraron que no existe diferencia estadísticamente significativa (p≤0,05) en los valores de dureza al emplear ambas soluciones amortiguadoras. Se concluyó que el empleo de la solución amortiguadora inodora de borato para la cuantificación de dureza total en agua es una alternativa a la solución amortiguadora de amonio.

Total Hardness determination EDTA in water using ammonium buffer solution pH 10 has the disadvantage of generating ammonia gas vapors are usually upset or be potentially harmful to the respiratory system operator. The aim of this study was to use a buffer solution pH 10 borate odorless replacing ammonium buffer solution at pH 10 for the determination of total water hardness in the methodology of COVENIN 2408-86 standard and determine whether there was difference statistically significant between the two procedures. Total Hardness was determined using borate buffer odorless in 13 water samples with different degrees of hardness (soft, hard and very hard); the results obtained were compared with the reference method values. The buffer allowed rapid and sharp display of the end point during the execution of the volumetric determination, the results showed that there was no statistically significant difference (p≤ 0,05) in hardness values by using two buffers. It was concluded that the use of borate buffer odorless for quantification of total hardness water is an alternative to the ammonium buffer.

Qualidade da Água Subterrânea na Região do Médio Vale do Itajaí - SC / Groundwater Quality in the Region of Médio Vale do Itajaí ? SC

A água é um bem inestimável, necessária para a manutenção da vida, para os processos industriais e irrigação agrícola. A água superficial potável está cada vez mais escassa, tornando mais comum o uso de águas subterrâneas. A água subterrânea geralmente é potável por natureza, porém, devido a modificações de origem antrópica, essa propriedade pode ser alterada. O objetivo deste estudo foi verificar a qualidade da água subterrânea na região do Médio Vale do Itajaí - SC. Para isso, foram utilizados os resultados de 51 laudos de exames físico-químicos e microbiológicos feitos por laboratórios de análise ambiental, localizados nas cidades de Timbó e Blumenau. Os resultados mostraram que 25 amostras (49,01%) tiveram algum dos parâmetros alterados. Separando por parâmetro, 12 (25,53%) amostras estavam contaminadas por coliformes totais e 4 (8,51%) por coliformes termotolerantes / E. coli. Na análise de pH, 7 amostras (19,44%) apresentaram valores abaixo do recomendado pela legislação e 6 (16,66%) amostras resultaram em valores de turbidez acima do máximo permitido. Apenas 1 (5,26%) amostra apresentou-se alterada na análise de odor e 5 (16,66%) estavam desconformes em relação a cor. Outras alterações encontradas foram níveis de ferro e amônia acima do permitido em 3 amostras. Diante das alterações encontradas, é recomendável que antes do consumo de água subterrânea, sua potabilidade seja certificada através de análises laboratoriais.

Water is a inestimable commodity, necessary for the maintenance of life, industrial processes and agricultural irrigation. Drinking surface water is increasingly scarce, making the use of groundwater more common. Although groundwater is generally potable by nature, this property can be altered by anthropogenic changes. The aim of this study was to verify the groundwater quality in the region of Médio Vale do Itajaí ? SC. For this purpose, the results of 51 reports of physicochemical and microbiological tests performed by environmental testing laboratories located in the cities of Blumenau and Timbó were studied. The results showed that 25 samples (49,01%) presented changes in the parameters evaluated. With respect to each parameter, 12 (25.53%) samples were contaminated by total coliforms and 4 (8.51%) by thermotolerant coliforms / E. coli. For pH, 7 samples (19.44%) were with values below the recommended by legislation and 6 (16.66%) presents turbidity values above the maximum allowed by law. Only 1 (5.26%) sample had altered odor, while 5 (16.66%) were nonconforming for the color attributes. Iron and ammonia levels were also above the permitted in 3 samples. Given the results, it is recommended the potability of groundwater be certified by laboratory analysis before the consumption.

Sensitive Determination of Polycyclic Aromatic Hydrocarbons in Water by Online Solid Phase Extraction Coupled with High Performance Liquid Chromatography / 分析化学

A method was developed for the determination of polycyclic aromatic hydrocarbons ( PAHs ) in water by HPLC coupled with online solid phase extraction ( online SPE ) . After filtered, 1 mL of a water sample was injected directly, and then trapped on the SPE column ( Acclaim PAⅡ, 50 mm × 4. 6 mm, 3 μm) for extraction and purification; finally, the trapped analytes were transferred to the analytical column (Hypersil Green PAH, 150 mm × 3 mm, 3 μm) for the separation using valve-switching technique. The mobile phase used for online SPE was water/acetonitrile at different flow rate ( 0 . 4 and 0 . 6 mL/min ) in gradient elution mode;and that used for the separation was water/acetonitrile at 0. 8 mL/min flow rate. UV wavelength was set at 254 nm for the determination of naphthalene and acenaphthylene with no/very weak fluorescent response;fluorescence detection using programmed wavelength switching in three parallel channels was used for the other PAHs. The whole analysis process including online SPE and separation was completed within 32 min. The relative standard deviation ( RSD) of 20 PAHs were all less than 0. 16% for retention time, and less than 1. 3% for peak area (n=7). The peak area had a good linearity with the sample concentration in three orders of magnitude with correlation coefficients of above 0 . 9910 . The recoveries for 0 . 05 μg/L of each analyte in tap water were in the range of 57%-140%, and for 5 . 0 μg/L of each analyte were in the range of 85%-116%. The limits of detection of the method were less than 0 . 05 μg/L ( S/N=3 ) for most PAHs.

O teor de fluoretos na água de consumo no ambiente escola e a perspectiva de controle da cárie dentária / The fluoride content of drinking water in the school environment and the prospect of controlling dental caries

A fluoretação da água de abastecimento público é considerada uma das dez melhores medidas de saúde pública no mundo, por ser um método de grande abrangência, por beneficiar todos os grupos socioeconômicos e ter uma excelente relação custo-benefício. O objetivo deste trabalho foi analisar a concentração de fluoretos na água de consumo no ambiente escolar do município de Vassouras e compará-lo com os padrões propostos pela OMS para controle da cárie dentária. A metodologia utilizada foi a captação em fontes de água potável localizadas em algumas escolas do município e analisadas pelo método químico colorimétrico no laboratório de análises químicas da USS. Os resultados apontaram uma variação de 0,01 à 0,38 mg/L-1 de fluoreto. O teste t de Student (one sample test) com t = -8,373, com valor de p<0,001, ao nível de significância de ?=0,05 (5%), confirma que as 16 escolas avaliadas provêm de uma população cuja média do teor de fluoretos é menor que 0,38 mg/L-1. Conclui-se que nas fontes pesquisadas o valor do teor de fluoretos encontra-se abaixo do mínimo recomendado pela OMS para o controle da cárie dentária, necessitando o município de suplementação artificial do íon para proteção da população em idade escolar.

The fluoridation of public water supplies is considered one of the ten greatest health measures in the world, for being a large scale method, benefitting all socioeconomic groups, and having an excellent cost-benefit ratio. The aim of this study was to analyze the fluoride concentration of drinking water at schools in the city of Vassouras, and compare it with the WHO standards for control of dental caries. The methodology adopted was to collect samples from potable water sources in a number of schools and analyze them using the colorimetric chemical method, at the chemical analysis laboratory, Severino Sombra University. The results showed a variation of fluoride between 0.01 and 0.38 mg l-1. The Student t-test (one sample test) with t = 8.373, p-value <0.001, with a significance level ?=0.05 (5%), confirms that the 16 schools assessed come from a population receiving water whose average fluoride content is less than 0.38 mg l-1. It is concluded that, in the sources studied, the fluoride content level is below the minimum recommended by the WHO for the control of dental caries, requiring the municipality to provide artificial supplementation of the ion to protect the school-age population.

Qualidade microbiológica da água paraconsumo humano em instituição de ensino deMaringá-PR / Microbiological quality of human consumption water in aschool in Maringa-PR

A água contaminada associada à falta de saneamento básico mata anualmente cerca de 1,6 milhões de pessoas no mundo.A falta da potabilidade da água nem sempre é perceptível à visão ou olfato, sendo necessária uma análise laboratorial paradetectá-la. Torna-se importante o controle microbiológico da água devido sua característica de veículo de transmissão debactérias, dentre estas, coliformes totais e termotolerantes, protozoários, vírus e fungos causadores de inúmeras doençasao homem. Esses micro-organismos são responsáveis pela ocorrência de diarreias, disenterias, hepatites, cólera, entreoutras enfermidades graves. Esta pesquisa teve por finalidade analisar a presença de coliformes totais e termotolerantesem amostras de água mineral engarrafada e água tratada. No presente estudo foram selecionados 50 locais para coleta deágua para consumo humano, todos localizados em uma instituição de ensino na cidade de Maringá-PR. Das amostras coletadas,13 foram provenientes de bebedouros de água mineral natural engarrafada e 37 amostras de bebedouros de pressãode água tratada na própria instituição de ensino. A metodologia empregada para pesquisa de coliformes foi o métodode fermentação em tubos múltiplos. O resultado deste trabalho revelou, por meio de análise microbiológica, que as amostrasde água tratada dos bebedouros de pressão apresentaram-se próprias para consumo humano. Entretanto, 15,38% dasamostras de água mineral apresentaram-se contaminadas por coliformes totais. Esses resultados demonstraram que a águatratada com cloro apresentou melhor qualidade microbiológica quando comparada à água mineral natural engarrafada.

Contaminated water associated with poor sanitation kills about 1.6 million people worldwide annually. Lack of potabilityin water is not always perceptible to the sight or smell, requiring laboratory analysis to detect it. Because of that it is importantto control microbiologically water since it is a vehicle of transmission of bacteria such as total and fecal coliforms,protozoa, viruses and fungi that cause numerous humans diseases. These microorganisms cause diarrhea, dysentery, hepatitis,cholera, among other serious illnesses. This research aimed at examining the presence of total and fecal coliformsin samples from bottled mineral water and treated water. In the present study 50 sites of drinking water were selected, alllocated in an educational institution in Maringá-PR. 13 of the collected samples were from water drinker dispensers withbottled natural mineral water and 37 samples were from water dispensers with water treated in their own institution. Themethodology used for detecting coliforms was the method of Multiple Tube Fermentation. The result of this study revealed– through microbiological analysis – that the samples of treated water were fit for human consumption. However, 15.38%of the analyzed mineral water samples were contaminated with total coliforms. These results showed that water treatedwith chlorine showed better microbiological quality when compared to bottled natural mineral water.

Seven years of external control of fluoride levels in the public water supply in Bauru, São Paulo, Brazil

Fluoridation of the public water supplies is recognized as among the top ten public health achievements of the twentieth century. However, the positive aspects of this measure depend on the maintenance of fluoride concentrations within adequate levels. Objective: To report the results of seven years of external control of the fluoride (F) concentrations in the public water supply in Bauru, SP, Brazil in an attempt to verify, on the basis of risk/benefit balance, whether the levels are appropriate. Material and Methods: From March 2004 to February 2011, 60 samples were collected every month from the 19 supply sectors of the city, totaling 4,641 samples. F concentrations in water samples were determined in duplicate, using an ion-specific electrode (Orion 9609) coupled to a potentiometer after buffering with TISAB II. After the analysis, the samples were classified according to the best risk-benefit adjustment. Results: Means (±standard deviation) of F concentrations ranged between 0.73±0.06 and 0.81±0.10 mg/L for the different sectors during the seven years. The individual values ranged between 0.03 and 2.63 mg/L. The percentages of the samples considered “low risk” for dental fluorosis development and of “maximum benefit” for dental caries prevention (0.55-0.84 mg F/L) in the first, second, third, fourth, fifth, sixth, and seventh years of the study were 82.0, 58.5, 37.4, 61.0, 89.9, 77.3, and 72.4%, respectively, and 69.0% for the entire period. Conclusions: Fluctuations of F levels were found in the public water supply in Bauru during the seven years of evaluation. These results suggest that external monitoring of water fluoridation by an independent assessor should be implemented in cities where there is adjusted fluoridation. This measure should be continued in order to verify that fluoride levels are suitable and, if not, to provide support for the appropriate adjustments.

Comparação entre métodos para a análise de coliformes totais e E. coli em amostras de água / Comparison of methods for analysis of total coliforms and E. coli in water samples

Neste estudo foram realizadas as contagens de coliformes totais e de E. coli por meio de três metodologias(fermentação em tubos múltiplos - FTM, Colilert e Colitag) em amostras de água coletadas de três diferentes pontos (abastecimento, bica e rio). O desempenho analítico dessas metodologias foi comparado analisando-se 90 amostras de água. Nas contagens de coliformes totais em amostras de água provenientes de bica e de abastecimento e nas contagens de E. coli em amostras de água coletadas de abastecimento, bica e rio, as técnicas Colilert e Colitag mostraram resultados equivalentes aos da metodologia FTM. Nas análises de coliformes totais em amostras de água do rio, a técnica de FTM apresentou diferenças significativas quando comparada aos testes rápidos. Esta diferença pode ter ocorrido pela presença de Aeromonas nas amostras ou, possivelmente, pela maior capacidade das técnicas Colilert e Colitag em recuperar as células danificadas. Dessa forma, nos casos em que as técnicas rápidas forem equivalentes à metodologia convencional, dá-se preferência ao uso dos primeiros testes, por serem mais rápidos, práticos e de menor custo.

The total coliform and E. coli counts were performed using three methodologies (Multiple-TubeFermentation - MTF, Colilert and Colitag) in water samples collected from three different points (watersupply, spout and river). The performances of three methodologies were compared analyzing ninety watersamples. In the analysis of total coliform of water samples from spout and supply and analysis of E. coliof water samples from supply, tap and river, Colilert and Colitag techniques were equivalent to MTF in counting these bacteria. However, for analyzing the total coliform in water samples collected from river, the MTF technique differed significantly from those rapid tests. This significant difference may be due to the presence of Aeromonas in water samples, or possibly because of the increased capacity of Colilert andColitag techniques in recovering the injured cells. Thus, in event of the rapid technique were equivalent to conventional ones, the former should be used, as they are fast, practical and inexpensive.

Toxicological study of nitrate/nitrite concentration in harvested rainwater from Kannur District of Kerala.

Rainwater harvesting is a technology used for collecting and storing rainwater from rooftops. The techniques usually followed in Asia and Africa arise from practices employed by ancient civilizations in these regions, and still serve as a major source of drinking water supply in rural areas. Of late, in Kerala (India), scientific methods are being increasingly employed for rainwater harvesting. But in some areas, for instance in Kannur district, where this study was conducted, the recommended scientific method is not followed properly, and high levels of nitrates (or nitrites) are said to be present, which can cause nitrate toxicity. This study mainly concentrates on the water quality analysis of rainwater harvesting area in Kannur district of Kerala. The following quality parameters were analyzed: pH, electrical conductivity, alkalinity, chloride, total dissolved solids (TDS), hardness, iron, ammonia, nitrate, nitrite, sulphate, and absorbed oxygen. It was found that most of these were within the prescribed international standards, but some parameters such as total dissolved solids (TDS), nitrate, nitrite and absorbed oxygen were quite high as compared to ground water. When the water was passed through commercially available filters, sand and gravel, or charcoal, the concentration of nitrate, nitrite, total dissolved solids and absorbed oxygen came down to acceptable levels, and the water satisfied all the drinking water quality standards, equivalent to the highest quality mineral water.

Validation of Two Portable Instruments to Measure Iron Concentration in Groundwater in Rural Bangladesh.

Iron is ubiquitous in natural water sources used around the world for drinking and cooking. The health impact of chronic exposure to iron through water, which in groundwater sources can reach well above the World Health Organization’s defined aesthetic limit of 0.3 mg/L, is not currently understood. To quantify the impact of consumption of iron in groundwater on nutritional status, it is important to accurately assess naturally-occurring exposure levels among populations. In this study, the validity of iron quantification in water was evaluated using two portable instruments: the HACH DR/890 portable colorimeter (colorimeter) and HACH Iron test-kit, Model IR-18B (test-kit), by comparing field-based iron estimates for 25 tubewells located in northwestern Bangladesh with gold standard atomic absorption spectrophotometry analysis. Results of the study suggest that the HACH test-kit delivers more accurate point-of-use results across a wide range of iron concentrations under challenging field conditions.

Dez anos de heterocontrole da fluoretação de águas em Chapecó, Estado de Santa Catarina, Brasil / Ten years of external control over water fluoridation in Chapecó, Santa Catarina State, Brazil

O objetivo deste estudo foi analisar a concentração de flúor na água de abastecimento público em Chapecó, Santa Catarina, Brasil, no período de 1995 a 2005 e, adicionalmente, avaliar a efetividade de uma intervenção ocorrida em 2003 na qualidade da fluoretação. Foram analisadas 989 amostras de água. Para adequação da concentração de flúor as amostras foram classificadas obedecendo a três critérios utilizados no Brasil. Uma intervenção político-jurídica foi realizada pela municipalidade no ano de 2003. A fim de avaliar a tendência da fluoretação ao longo de todo período e antes e depois da intervenção, utilizou-se o procedimento de Prais-Winsten. Nos dez anos analisados, o sistema de fluoretação de águas apresentou 46 por cento, 32 por cento e 43 por cento de amostras adequadas, dependendo do critério adotado. Previamente à intervenção municipal, a proporção de amostras adequadas foi de 40 por cento, 26 por cento e 36 por cento, aumentando para 63 por cento, 49 por cento e 61 por cento após intervenção, segundo os diferentes critérios de análise. Verificou-se uma melhora na adequação da concentração de flúor após a intervenção municipal. Recomenda-se a continuidade da vigilância da fluoretação de águas, considerando-a processual e de caráter permanente.

This study aimed to analyze fluoride concentration in the public water supply in Chapecó, Santa Catarina State, Brazil, from 1995 to 2005 and to assess the effectiveness of a fluoridation quality intervention in 2003. A total of 989 water samples were analyzed. Fluoride concentrations were classified according to three different criteria used in Brazil. The city conducted a political and legal intervention in 2003. The Prais-Winsten procedure was used to evaluate the fluoride concentrations over time. In the ten years, the water fluoridation system showed 46 percent, 32 percent, and 43 percent of adequate samples, depending on the criterion. Prior to the municipal intervention, the proportion of adequate samples was 40 percent, 26 percent, and 36 percent, increasing to 63 percent, 49 percent, and 61 percent after the intervention, according to the three criteria. Fluoride concentration improved after the municipal intervention. On-going surveillance is recommended, including water fluoridation, dental caries, and dental fluorosis.

Luminescent bacteria as biosensor for mercury toxicity.

Agricultural activities and human industrialization are mainly responsible for the release of heavy metals into the environment, especially the air and the water. The first step towards the effective management of water resources is the assessment of pollution levels. Biosensors for the detection of pollutants in the environment can complement analytical methods by distinguishing bioavailable from inert, unavailable forms of contaminants. A bioassay system for detecting heavy metals in water using bioluminescent bacteria, Vibrio harveyi and Vibrio fischeri has been developed, which offers the advantages of simplicity and rapidity for screening heavy metals in water sources. Bioluminescence was found to be species specific and strain specific. Mercury, zinc and copper showed definite microbial toxicity and inhibition of bioluminescence. The inhibition range for each strain of a species was standardized and its reproducibility verified. The utility of the biosensors to detect heavy metals in tap water was demonstrated with samples supplemented with Hg (II).