Why Indoor Swimming Pools May Increase Cancer Risk


Your indoor swimming pool at the gym could pose a cancer risk, according to results of a new study. Exposure to chlorinated pool water may promote DNA damage, which can lead to cancer, giving new meaning to the question, Is it safe to go into the water?

Swimming Pools and Risk of Cancer

This latest study, which was published in a series of three articles in the journal Environmental Health Perspectives, is the first to provide a detailed look at the impact of disinfection by-products (DBPs) in indoor swimming pools and the first to evaluate the cancer-causing potential of exposure to DBPs in an indoor pool.

Previous research conducted at the University of Illinois and published this past summer found that disinfectants used in swimming pools may be associated with asthma and cancer. In this study, water samples collected from public pools was found to contain more genomic DNA damage than tap water.

New Swimming Pool Study
Investigators collected water samples from two indoor pools: one had been disinfected with chlorine, the other with bromine. They also evaluated short-term changes in biomarkers of genotoxicity (damaging to DNA) and the impact on respiration in 49 healthy adults who swam in the chlorinated pool.


Investigators found increased levels of two genotoxicity biomarkers related to the concentration of the most common types of DBPs in the exhaled breath of the 49 swimmers. The elevated biomarkers were seen in micronuclei in blood lymphocytes, which has been associated with a risk of cancer in healthy individuals; and mutagenicity in urine, which is an indication of exposure to genotoxic factors.

Researchers also identified more than 100 DBPs in the swimming pool waters, and some of the elements had never been reported in either pool water or chlorinated drinking water. Testing revealed that the swimming pool water had cancer-causing potential at levels similar to that seen in drinking water but had a greater ability to kill cells at a lower concentration than drinking water.

The authors note that their work involved short swim times and that further research is needed involving longer exposure. Additional investigation is also needed of different swimming pools under different conditions regarding type of maintenance and use, especially the types of compounds used to treat indoor swimming pool waters.

For more information on the research on how indoor swimming pools may increase cancer risk and the DBPs in swimming pool water, you can access articles at the Environmental Health Perspectives website.

Environmental Health Perspectives
Liviac D et al. Environmental Science & Technology 2010 May 1:44(9): 3527-32