Recently, it is becoming increasingly important to protect the skin from ultraviolet rays. However, many Japanese schools do not permit the use of sunscreens in swimming pools, the main reason being “pollution of pool water”. In Osaka Prefecture after the swimming season in the summer of 2007, we examined the quality of swimming pool water (pH, turbidity, free residual chlorine, potassium permanganate consumption,
Escherichia coli, and trihalomethane) at 14 junior high schools: sunscreens allowed in 4; conditional use in 3; banned in 7. The results showed that, among the 6 standards for school environmental health defined by the Ministry of Education, Culture, Sports, Science and Technology, there were no deviations from the reference values for turbidity, potassium permanganate consumption,
Escherichia coli, or trihalomethane. Free residual chlorine and pH tended to deviate from the reference values at schools where sunscreen agents were permitted to be used freely or under certain conditions. A statistical investigation is difficult to perform due to the small number of samples and differences in conditions at each school, but if the residual chlorine concentration in pool water is periodically measured and controlled and makeup water is added, then it appears that there should be no problem in using sunscreen agents in order to prevent damage caused by ultraviolet rays.
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