Swimming Pools: Cancer Causing?

As summer approaches, swimming is a popular activity and a great way to keep in shape during the heat-filled lazy days. Working out in water enables more muscles to be exercised, while putting relatively little stress on the joints. This makes swimming as an ideal workout for those affected by arthritis. However, people should be aware that while swimming does have health benefits, swimming pools do have carcinogenic (cancer-related) risks associated with them. It is important for swimmers to be aware of the pros and cons associated with the water they will be splashing in these upcoming months.

Pool water is not just composed of filtered tap water, but it’s also treated with chemicals in order to rid the water of potentially dangerous germs and pathogens. To keep the pool clean and germ-free, the most common chemical used in order to disinfect the pool water is a chlorine-based disinfectant. This disinfectant, which is both effective and relatively inexpensive, releases hypochlorous acid into the water that destroys the harmful bacteria found in the pool. Aside from reacting with the matter already in the pool area, the chlorine also reacts with organic substances that the swimmers themselves introduce into the pool, such as sweat, urine, lotion, and sunscreen. These reactions produce harmful disinfectant byproducts, known as DBP’s.

Chemicals from the water may affect people in the pool either through skin-contact with the water, or by swallowing the pool water. Often, the chemical reactions that take place between the chlorine and the materials in the pool water cause gases to be released into the pool atmosphere and stay above the water. Aside from ingesting the water with the DBP’s and absorbing them through their skin, swimmers breathe in chemicals from the air above the pool. In indoor pools, chloroform and trichloramine are present in the air, and various aerosols are found above the surface of outdoor pools. Interestingly, heated pools also have a higher concentration of DBP’s than unheated pools.

A study done on swimming pool water was performed and significant mutagenic responses were recorded. A high level of DNA breaks were found in cultured human cells after exposure to chlorinated water. Additionally, an investigation conducted in 2010 examined urine samples collected from people before and after swimming. An Ames assay, or assay that tests for mutagenicity of a substance, showed a significant rise in the mutagenicity of the urine samples after swimming. Blood samples from the swimmers were also obtained, and an increased frequency of DNA damage was observed. Research done on reconstructed human skin also showed that there was abnormalities in the cells of the skin models upon exposure to the DBP’s in the chlorinated water.

Moreover, a study compared the mutagenicity of pool water and drinking water. Surprisingly, the researchers learned that while the pool water did have genotoxic properties, so did the drinking water. In fact, they discovered that the drinking water was just as mutagenic as the swimming pool water.

Additional research has been done to determine whether swimming pool water may cause asthma. Some studies have concluded that the gases released by the chlorination in water treatments can result in induced asthma. This would help explain why asthma affects a higher percentage of athletes who swim than athletes who do not. Yet it is still unclear whether chlorine actually causes asthma, or whether people with asthma are more likely to swim.

It is important to work on gaining a better understanding of the chemistry of swimming pool water and the potential risks associated with the water. Most of the research on the effects of disinfectant by-products from the chlorination of pool water has only been published in the last few years, so this field of research is still relatively new. Although the potentially adverse health effects of the pool are not fully known, steps may still be taken in order to minimize harm. The general public should become more willing to modify their behaviors in relation to swimming pools and there are a few hygiene requirements that public pools in the United States can require of their swimmers either before or during swimming. Public swimming pools should oblige their participants to shower before entering the pool area, which will reduce the amount of disinfectant needed and therefore the amount of DBP’s that the swimmers will be exposed to. Swimmers should also be encouraged to take frequent bathroom breaks. By making the public more aware of pool hygiene, swimming pools will become a safer and healthier place for people to swim in, whether for exercise or pleasure.