Fecal bacterial indicator analyses have been widely used for monitoring the water quality. This study was designed to determine the ratio between the density of Escherichia coli and other Thermotolerant Coliforms (TtC) bacteria from freshwater samples collected for a two-year period of monitoring. TtC were enumerated by membrane filtration on mFC agar. E. coli enumeration was done by two methods: TtC colonies identified in mFC were inoculated in EC-MUG or water samples were filtered and inoculated in modified mTEC agar media, and both methods were compared for quantitative recovery of E. coli. The results pointed out a mean percentage of E. coli among other thermotolerant coliforms (E. coli/TtC ratio) of 84.3% in mFC media. Taking these results into account, a mandatory standard of 1000 thermotolerant coliforms would correspond to 800 E. coli and the adoption of these E. coli based standards will represent a major improvement for the monitoring of freshwater quality.

Foi realizada uma avaliação sanitária das águas e areias de 16 praias do litoral do Estado de São Paulo, Brasil, durante a primavera de 1997 e verão de 1998. Cento e noventa e duas amostras de areia seca e úmida, e 96 amostras de água do mar, foram coletadas e analisadas quanto à presença de bactérias indicadoras de contaminação fecal. Também foram realizados exames parasitológicos e análises de Candida albicans nas amostras de areia, e a determinação de bacteriófagos F-específicos nas amostras de água. A análise estatística dos resultados demonstrou concentrações mais elevadas de coliformes e estreptococos fecais na areia seca, durante o verão. Observou-se uma correlação significativa (Pearson) entre as concentrações de coliformes fecais e estreptococos fecais para os dois tipos de areia, correlação esta mais elevada na areia úmida. Ovos e cistos de parasitas e C. albicans foram detectados em 4,2% e 18% das amostras, respectivamente. As elevadas densidades dos indicadores de contaminação fecal detectadas nas areias durante o verão mostram a necessidade de orientar-se adequadamente a população a respeito das doenças veiculadas pela areia e das medidas preventivas necessárias, bem como de buscar-se um critério adequado para monitorar esse risco.

A sanitary evaluation of sand and water from 16 beaches of São Paulo State, Brazil, was undertaken during spring of 1997 and summer of 1998. Ninety six samples each of wet and dry sand and seawater were collected and analysed for fecal indicator bacteria. A parasitological examination and Candida albicans analysis were also performed in sand samples and F-specific bacteriophages were determined in seawater. Statistical analysis of the results demonstrated higher concentrations of fecal coliforms and fecal streptococci in dry sand during summer. Correlation analysis indicated a significant relationship between fecal indicator densities in wet sand and seawater. There was a significant correlation between the densities of fecal coliforms and fecal streptococci for both types of sand, and this correlation was higher in wet sand. Cysts and eggs of parasites were detected in 4.2% of the samples and Candida albicans was isolated in 18% of the samples. The high concentrations of fecal indicators detected in sand during summer demonstrate that there is a health risk to the users of these recreational areas and suggest the necessity of some criteria for microbiological control. Preventive measures, such as education campaings and some management actions are important precautionary measures.