US drinking water: fluoridation knowledge level of water plant operators

An assessment of compliance with optimal fluoride levels for oral health benefit by New Zealand drinking water suppliers

OBJECTIVES

Community water fluoridation (CWF) has proven oral health benefits. We investigated whether drinking water suppliers are meeting New Zealand CWF targets (0.7-1.0 ppm) to ensure these benefits.

METHODS

We retrieved fluoride testing data from 25 supplies serving 2,059,000 people (82% of people on a fluoridated supply), for the years 1992-2022 (22,220 weekly observations). We descriptively assessed compliance with fluoride targets in this convenience sample.

RESULTS

The mean fluoride level was 0.66 ppm (SD 0.28). Water suppliers achieved fluoride targets 54.1% of the time (range 4.2%-77.9%). Fluoride concentration fell short of the target in 42.2% of observations, exceeded but under the maximum acceptable value (MAV) in 3.6%, and in excess of the MAV in 0.1%. The percentage of compliant observations was greater in larger than smaller supplies.

CONCLUSIONS

Noncompliance with CWF targets was common. Epidemiological studies that rely on fluoridation status as their exposure may underestimate the oral health benefits of CWF. Our results highlight future challenges with the feasibility of expanding CWF under new legislation as well as the weaknesses in drinking water surveillance.

Municipality-Level Characteristics Associated with Very Low to Good Quality of Water Fluoridation in São Paulo State, Brazil, in 2015

INTRODUCTION

Community water fluoridation (CWF) is a measure of recognized importance due to its effectiveness in preventing tooth decay at the population level. However, for the maximum benefit to be achieved, the high-quality standard of CWF must be maintained over time.

OBJECTIVE

To analyze the municipality-level characteristics associated with quality of water fluoridation in São Paulo state, Brazil.

METHODS

An ecological study was performed using official data sources on fluoride concentration surveillance in 2015. The outcome was municipalities that have not met the quality standard, identified as those with less than 80% of water samples within the optimal level for caries prevention. The independent variables were municipality-level indicators related to demographics, economics, and sanitation characteristics. Crude and adjusted prevalence ratios were estimated using Poisson regression with robust variance.

RESULTS

In total, 43.4% municipalities exhibited the outcome. Adjusted by Gini index, the prevalence ratio was 32% higher in municipalities with lower annual gross domestic product per capita. Adjusted by social responsibility index and earlier variables, the prevalence was higher in the municipalities with higher per capita expenditure on sanitation and health surveillance, where the urban population rate was lower, and with a human development index ≤0.761. Adjusted by earlier variables, the prevalence ratio was twice and 3.5 times higher for municipalities, respectively, with per capita income less than or equal to US$574 and where the type of sanitation utility was municipal and private; 50% higher in those with less than 100,000 habitants; and 20% higher in those with a chlorine concentration nonconformity rate above 0.82%.

CONCLUSIONS

To ensure high quality of CWF, additional management measures should be implemented in municipalities with less than 100,000 habitants, a higher chlorine concentration nonconformity rate, a lower per capita income, and where the type of sanitation utility was municipal or private.

KNOWLEDGE TRANSFER STATEMENT

The study showed that the quality of fluoridation was associated with municipality-level characteristics. The findings can be used by policy makers to identify and support municipalities that will need to improve fluoridation quality if they are to reach oral health goals.

Vigilância da qualidade da água para consumo humano: potencialidades e limitações com relação à fluoretação segundo os trabalhadores

RESUMO Os trabalhadores da vigilância da água exercem importante papel na implementação do Programa Nacional de Vigilância da Qualidade da Água para Consumo Humano e detêm informações sugestivas do grau de estruturação e da institucionalidade das práticas no âmbito local das organizações sanitárias. O estudo objetivou descrever as potencialidades e as limitações relativas à vigilância da fluoretação da água em uma região metropolitana brasileira segundo a visão dos trabalhadores. Realizaram-se entrevistas semiestruturadas com profissionais de sete municípios da região metropolitana do estado do Espírito Santo, Brasil, que foram gravadas, transcritas na íntegra e interpretadas segundo a Análise de Conteúdo Temática. Os resultados permitiram a elaboração das categorias: recomendações da legislação e a prática do heterocontrole da concentração do fluoreto; dificuldades e potencialidades do processo de trabalho; disseminação das informações para a sociedade. A maioria dos trabalhadores seguia as recomendações da legislação vigente no período das entrevistas (Portaria MS nº 2.914/2011), porém, notou-se a necessidade de adequações estruturais e organizacionais. O processo de vigilância do fluoreto enfrenta problemas que envolvem a coleta da amostra, as análises e a divulgação dos resultados. É nítida a necessidade de maior priorização e alocação de recursos para ampliação e qualificação da vigilância dessa medida de saúde pública.

Long-term variability in artificially and naturally fluoridated water supplies in England

OBJECTIVES

To understand the potential impact of exposure misclassification on water fluoridation studies in England, this paper aims to describe the long-term variation in water fluoride concentrations in both artificially and naturally fluoridated water supplies.

METHODS

Water fluoridation dose monitoring data were requested from all five English public water suppliers who artificially fluoridate their water, as well as from one water company that supplies naturally fluoridated water. Descriptive statistics were calculated, including annual means, standard deviations, minimum-maximum and absolute and relative frequencies.

RESULTS

Data were made available by two of the five English water companies who supply artificially fluoridated water and one water company that supplies naturally fluoridated water (40 398 individual samples). The data for fluoridated water spanned 18-35 years, whilst the data on naturally fluoridated water spanned 14 years. The artificially fluoridated samples showed wide variation in fluoride dose control, both between different water treatment works and over time. Mean fluoride concentrations in the artificially fluoridated supplies ranged from 0.53 (SD 0.47) to 0.93 (SD 0.22) mg F/L and were within the optimal range of 0.7-1.0 mg F/L in 27.7%-77.8% of samples. The naturally fluoridated supplies had a higher mean fluoride concentration of 1.06 (SD 0.18) and 1.15 (SD 0.16) mg F/L than the artificially fluoridated supplies, with lower variation over time. The naturally fluoridated supplies were above the optimal range in 75.5% and 53% of samples.

CONCLUSIONS

Assumptions that populations living in areas with a water fluoridation scheme have received optimally fluoridated water (0.7-1.0 mg F/L) are invalid. To support future research endeavours, as well as to provide 'external control' and facilitation of optimal dosing, it is recommended that a quarterly record of water fluoride concentrations (mean, standard deviation and minimum and maximum) are made available for every water supply in England, in a format that can be mapped against residential postcodes.

Maintenance of Optimal Fluoride Levels in Public Water Systems

OBJECTIVE

This study examines the quality of water fluoridation in public water supplies.

METHODS

An assessment of daily fluoride levels among all communities that fluoridate their public water supplies in New Hampshire was conducted from January 1, 2000, through June 30, 2002. Results were compared against recommendations from the Centers for Disease Control and Prevention.

RESULTS

The fluoride concentration was less than the recommended minimum value on 42.0 percent of days, within the accepted control range on 49.8 percent of days, and above the recommended maximum value on 1.0 percent of days. On 7.1 percent of days, a fluoride concentration was not determined. Only 2 (18.2%) of 11 public water supplies maintained the fluoride concentration in the optimal range > or =80 percent of the days.

CONCLUSIONS

For public water supplies in New Hampshire that fluoridate, suboptimal levels are the most common problem. Water systems need to better maintain recommended fluoride levels if communities are to realize the full benefits of fluoridation.

Vinte e quatro meses de heterocontrole da fluoretação das águas de abastecimento público de Pelotas, Rio Grande do Sul, Brasil

O objetivo deste estudo foi monitorar, mensalmente, os níveis de flúor na água de abastecimento público de Pelotas, Rio Grande do Sul, Brasil, bem como verificar a validade da formação de grupos de heterocontrole. Pelotas foi dividida em 16 pontos geográficos, incluindo as três Estações de Tratamento da água e a coleta foi feita de novembro de 1999 a outubro de 2001, em duplicata. Após a coleta, as amostras foram enviadas ao Laboratório de Vigilância Sanitária de Flúor da Universidade do Vale do Itajaí, onde a análise foi feita utilizando-se o método eletrométrico (Orion 920A/Eletrodo Orion 9609). Após 24 meses, 764 unidades amostrais foram coletadas e verificou-se uma inconstância nos resultados, predominando níveis insuficientes de flúor até o primeiro trimestre de 2001, quando houve um significativo aumento no número de unidades amostrais com uma concentração de flúor ideal (0,6-0,9ppmF), porém, há o surgimento de pontos revelando um excesso de fluoretos (> 1ppmF). Os resultados permitiram concluir que o heterocontrole é fundamental para buscar a manutenção de um correto programa de FAAP.

Fluctuations in public water fluoride level in Bauru, Brazil

OBJECTIVES

The aim of this study was to monitor the quality of public water supply fluoridation in Bauru, in the state of São Paulo, Brazil.

METHODS

Water samples collected three times a week during four weeks in 20 areas of distribution of water were supplied by the City Water Department of Bauru, São Paulo, Brazil. Fluoride was analyzed using the ion-specific electrode (Orion model 9409) after sample buffering with an equal volume of TISAB II. Data were compared to fluoride concentration reported by City Water Department.

RESULTS

Fluoride content ranged between 0.01 ppm and 9.35 ppm (n = 240). There was great variation among the different areas of distribution of water, as showed by the Levene test (P < .001). Kruskal-Wallis test showed a statistically significant difference in mean fluoride concentration among different areas (P < .001). Mean fluoride concentration was less than the optimum concentration (0.8 ppm) in 89 percent of samples. The values reported by the City water Department were always higher than the analyzed fluoride concentrations.

CONCLUSIONS

Based on the results from this study, more rigorous surveillance and monitoring of water fluoridation in Bauru is recommended.