Avaliação ecoepidemiológica e sanitária de piscinas coletivas da cidade de São Carlos - SP

Abstract

A hundred sixty samples of water were collected to assess the sanitary and ecoepidemiological conditions of collective swimming pools in São Carlos SP. The samples were collected between August/2007 and Abril/2008. The pools were characterized by application of a questionnaire, answered by people responsable for the water treatment. Physical and chemical analysis included: pH, temperature, alkalinity, free chlorine concentration and turbidity. All water samples were analyzed for heterotrophic plate counts by pour plate method. Membrane filter technique was used to isolate amoebae and other bacteria. Eleven pools were heated and nine were unheated. Half of the pools was indoors and the other half was outdoors. Seventeen pools were chlorinated and three pools had a combined disinfection, two using chlorine and UV and one using chlorine and ozone. Only 13 samples (8%) conformed within the desired standards for pH, turbidity and free chlorine concentration at the same time. Twelve samples (7.5 %) were unacceptable for heterotrophic bacteria and 63 (39 %) were unsatisfactory for the presence of total coliforms. Escherichia coli was detected in two samples. Moreover, 102 samples (64 %) were contaminated with at least one microorganism.The percentages of occurrence were: 14 % for Staphylococcus spp, 35 % for Pseudomonas spp, 33 % for Mycobacterium spp and 21 % for free-living amoebae. The amoebae identified were used to recover bacteria possibly present intracellularly . Of these 33 samples positive for protozoa, 18 (54 %) harbored Mycobacterium spp, 15 (45 %) harbored Pseudomonas spp and one (3 %) harbored Staphylococcus spp. Escherichia coli was not recovered from amoebae. The physical and chemical parameters most related to the occurrence of microorganisms in the samples studied were pH and chlorine. No significant relationship was identified between water temperature and occurrence of microorganisms. Overall, the inappropriate forms of treatment and maintenance of swimming pools studied might create conditions for the development of microorganisms, including those potentially pathogenic for human.