Whether water is hot in a tub or cold in a pool, it can bring immediate relief from stress or summer heat. But hot tubs and swimming pools are not always as clean as you might think, even when disinfected. In a new study in ACS’ Environmental Science & Technology, scientists have found that the more these facilities are used, the more potentially harmful compounds they contain.

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. 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. Susan D. Richardson and colleagues took a closer look at hot tubs, in addition to pools, to help flesh out potential problems with disinfection byproducts.

read more

Dr. Stegall’s Comments: I generally discourage people from routinely using chlorinated water. Swimming pools and hot tubs are two obvious sources, but we can’t ignore other, more routine sources such as tap water. Municipal water supplies have a significant amount of chlorine, which enters our bodies through drinking water as well as water we use for showering, bathing, and washing our hands. These exposures, over the long term, are not good for us. The solution? Use filtered water whenever possible. At home, this would ideally be a whole house filter which removes contaminants such as chlorine and fluoride as it enters your house. Instead of chlorinated swimming pools, I recommend salt water pools. Although we cannot avoid chlorine and other potentially harmful chemicals entirely, we can take steps to reduce our exposures.