Risk assessment of exposure to chlorine and its by-products in public/private swimming pools
Summary
The increasing concern about the effect of chlorine used to disinfect swimming pools allows research to focus on the effect of chlorine and its derivates on the development on cancer among bathers/swimmers but also workers.
A reaction between chlorine and compounds already present in the swimming pool water and those chemicals brought in by the bathers/swimmers e.g. sweat, urine, dirt, saliva, cells and all kind of lotions produce products called “disinfection by-products” (DBPs). These DBP are mainly composed of trihalomethanes including mainly chloroform, chloramines, haloacetic acids and nitrosamines. These products can be carcinogenic at certain concentrations.
The risks assessments for swimmers/bathers and workers are assessed with the NOAEL (No Observed Adverse Effect Level) given by authorities. These data were compared with earlier studies and French government analyses of swimming pool water. These risks assessments show that the concentrations of chloroform and chloramines are mainly lower than the NOAEL. Compared to a concentration considered as a discomfort concentration by the French government, results showed chloramines concentrations above that threshold. Swimmers/bathers and also workers can experience some discomfort like irritations in the eyes, and coughing making the time spend in the swimming pool less pleasant. Furthermore, the risk of developing cancer by going to the swimming pool is significant for the inhalation of chloroform.
A comparison between two countries was made, France and Australia. The guidelines were compared. For most of the criteria, the guidelines allow almost the same concentrations. There are also some differences; e.g. it is not allowed to use any stabilizer in indoor swimming pools in Australia, which is allowed in France. The concentration of chlorine should be minimal 3 g/L in Australia when there is stabilizer present while in France this concentration must be minimal 2 mg/L. The concentration of DBPs maybe higher in Australia than in France because there is more chlorine present in the water, while the disinfectant effect is not necessary higher because of the presence of stabilizer.