The disinfection of swimming pools and other recreational water systems with chlorine is a very important and fundamental component of routine pool operation. Chlorine is a powerful oxidizer and is very effective in performing its role as a primary sanitizer. One of the negative aspects of chlorine disinfection is the production of disinfection byproducts (DBP). DBP are compounds formed when chlorine oxidizes the organic contaminants present in swimming pools and spas. Some of these organic contaminants are present in the source water and many more are introduced through normal pool usage. Chlorination of recreational water leads to the formation of numerous potentially toxic DBP such as trihalomethanes, chloramines, haloacetic acids, haloacetonitriles and trihaloacetaldehydes. A number of epidemiologic studies have shown that chronic exposure to these DBP results in increased incidences of asthma and other respiratory ailments in competitive swimmers and pool workers.
There are also reports of increased ocular, sore throat and phlegm symptoms for lifeguards and swimming instructors. Studies have also demonstrated increased bladder cancer and genotoxicity in swimmers. In addition, a recent study has linked increased DBP production and mutagenicity in swimming pool and spa water directly to human organic contamination inputs. As chlorine disinfection is a requirement for the operation of commercial pools and spas, as well as standard operating procedure in most other pools and spas, the only way to reduce DBP production is to reduce the level of organic contamination that can be oxidized. This session will review the chemistry of DBP production as well as discuss the identified health effects of exposure to DBP in the water of pools and spas and the air of recreational water facilities. Finally, strategies to reduce organic loads in pools and spas, and thereby reduce DBP production, will be discussed.