Let's Take a Gene-Mutating Dip in the Pool!

Summer feels like it is just moments away, and that means you and your family will be cooling down in your neighborhood or backyard pool. Or maybe you prefer the rush of a hot tub? Either way, you are guaranteed some momentary relief from the stress and humidity in the clean water, right? But what if we told you that water was not as clean as you thought it was?

In a new study just published in Environmental Science & Technology, scientists have found that the more these hot tub and pool facilities are used, the more potentially harmful compounds they contain. It's not that the chlorine and all those other disinfectants aren't doing their job; they're actually part of the problem.

Disinfectants such as chlorine kill pathogens in hot tubs and swimming pools, whether they are personal or public facilities. But disinfectants also react with sweat, urine and other substances that users add to the water. Studies of swimming pools have identified many of the resulting compounds, called disinfection byproducts (DBPs). And testing has shown that they can cause genetic damage to cells in lab settings. Other reports have found that some people who swim or work in and around pools have higher rates of certain health problems, including respiratory symptoms and bladder cancer.

Study co-author Susan D. Richardson, of the Department of Chemistry and Biochemistry at the University of South Carolina, and her colleagues sampled water from public and private hot tubs and pools from tap to basin, and after both normal and intense use. They identified more than 100 disinfection byproducts in the water and tested extracts of the samples for their potential to cause genetic damage to cells in the lab. On average, pool and hot tub samples were 2.4 and 4.1 times more mutagenic, respectively, than the original tap water used to fill them.

"Although disinfection is important to inactivate harmful pathogens, adverse health effects associated with exposure to DBPs, such as asthma and bladder cancer, have been noted in human epidemiologic studies," say the authors.

Heavy use increased mutagenic potencies further. But, the researchers say, pool and hot tub operators could reduce disinfection byproducts by cleaning facilities and changing water more frequently. In addition, they could encourage swimmers to shower before sliding in and to use toilets when needed.

"Thus, encouraging practices that reduce these inputs, such as frequent cleaning of spas, more frequent exchange of water in pools, showering before entering pools/spas, and not urinating or wearing personal care products while in pools/spas, should have a beneficial effect on public health.