URTIGA, R. F.; URTIGA, Rui Francisco.
Résumé:
The present research had as objective the study of physico-chemical and bacteriological parameters in public and private swimming pools, for adults and for children of the municipalities of Campina Grande and Boqueirão, in order to analyze the factors that contribute to the deterioration of its waters and to suggest criteria for local application of sanitary standards. A sample collection technique was also evaluated for bacteriological analysis. This study was carried out from July to December 1987. The collections were made on Sundays and from 11:00 to 15:30 hours, since it is the one with the highest frequency of users. The physico-chemical parameters studied were: temperature, pH, transparency, turbidity, visibility, free and combined residual chlorine, chlorides, hardness and total alkalinity. The bacteriological parameters were: fecal coliforms (CF), fecal streptococci (EF), Staphylococcus spp (ST) with identification of S. aureus, Pseudonomas aeruginosa (PA) and heterophthroid facultative bacteria mesophilic (BFHM). (where present, their concentrations were lower and are minimum recommended of 0.2-0.4 ppm), high values of turbidity, pH, hardness, chlorides and total alkalinity , absence of recirculation and filtration in the hours of use in 50% of the swimming pools, high numbers and high frequency of isolation of all the bacteriological indicators. The most deficient conditions were observed in children's pools. In most swimming pools there was an association between an increase in the number of bathers and an increase in the number of indicator bacteria, and the pools without recirculation and filtration had a more significant association. It was concluded that the standard turbidity range of 1.0 to 5.0 NTU used for potable water can not be applied in swimming pools since all turbid samples higher than 3.0 NTU corresponded to negative transparency, out of standards. A maximum turbidity of 1.5-2.0 NTU could be more adequate, since approximately 60% of the determinations; with this turbidity corresponded to the average transparency. It was observed that the standard value of 250 mg Cl- / l could not be applied in our region, since the water supplying the pools contain a mean concentration of 311 mg Cl- / l. Among the isolated bacteria, it was observed that: Staphylococci, especially S. aureus, are good indicators of disinfection efficiency due to their high resistance to chlorine. Fecal streptococci proved to be more resistant to environmental conditions than fecal coliforms, and therefore are important indicators of fecal contamination, especially when faecal coliforms are absent. The results suggest that the main causes of the deterioration of the water were the deficiencies of the physical-chemical treatment, which favored the presence of the bacteria, introduced mainly by the bathers. In the public swimming pools, there were marked bacteriological changes in relation to the feed water. For example, fecal coliforms increased 20-fold in a fill-and-empty pool and 235-fold in a continuous-flow pool. There were no statistically significant differences between the numbers of bacteria present in the samples collected at 50cm from the surface and at the water column up to 1.0 meter deep.
