[Trihalomethanes in swimming pool water in four areas of Spain participating in the INMA project]

Objective: Swimming is one of the most widely practiced sports in Spain among people of all ages and physical conditions. This activity is also a source of exposure to disinfection by-products (DBP), which are potentially toxic. The DBP concentration in swimming pool water is not regulated and is poorly known. The aim of this study was to describe trihalomethane concentrations in swimming pool water in the municipalities of four cohorts of the INMA project.

Methods: In July 2009, trihalomethanes were analyzed in water from 27 swimming pools in Asturias, Granada, Valencia and Sabadell.

Results: The mean total trihalomethane concentration was 42.7 μg/L (standard deviation [SD]=19.1) in indoor pools and 151.2 μg/L (SD=80.7) in outdoor pools. In all pools, the most abundant trihalomethane was always chloroform. The lowest levels were found in Granada.

Conclusion: Trihalomethane concentrations in swimming pool water were highly variable. Outdoor swimming pools showed the highest levels, which were usually above the legal limit for drinking water.