Introduction: Indoor swimming pools are the most important recreational centres. Swimming pool water is responsible for the transmission of parasitic diseases. This study was performed to determine the rate of parasitic contamination and some physio- chemical parameters of indoor swimming pools in Urmia during 2002.
Materials and Methods: This study was a descriptive-cross sectional one in which four indoor swimming pools, were studied during the course of one year. A plastic pump was used to collect sample from the swimming pools. The sample size (384) was determined by statistical formula. The grab and simple random sampling methods were used to analyse the data. In the first and third week of each month, 8 samples of 200 ml and another 8 samples of 1000 ml were collected from the surface and the deep part of the pools. We expected that the total number of samples in one year would be 768, but because of Ramadan and winter season, we only managed to collect 526 samples in that year. The filter membrane, and sedimentation Leeds II method were used for 200 ml and 1000 ml respectively. Also a total number of 263 samples were used within one year for the examination of physio-chemical parameters, such as pH, temperature, turbidity and residual chlorine. Moreover, the number of swimmers who used the pools on one day was counted.
Findings showed that, 47 (8.9%) parasitic contamination samples were identified out of 526 total samples. The most important contaminants were, 13 (27.7%) Entamoeba coli, 1 (2.1%) Hymenolepis- nana, 3 (6.4%) Oxyuris and 30 samples (63.8%) contained larvae from the family of rahbditida and nematodes. Results also showed that the amount of residual chlorine at the university pool was (0.54±0/428) mg/l less than at others. The value of temperature in the Haft Tir pool was more than at the others (30.72±1.621). The maximum and minimum of pH were 9 and 7 for the university and Haft-Tir pools
respectively. The rate of contamination in Haft- Tir and Municipal swimming pools was
higher in comparison with the others. Moreover, the rate of contamination was higher in the Summer time (July to September).
Conclusion: According to the findings of this research, all the studied swimming pools were contaminated with parasites. We can conclude that the current disinfections used in swimming pools are not working efficiently and may not be based on the approved standard methods. It is recommended that more attention be played to the environmental health of the swimming pools.