Urine in swimming pools is one of those awkward facts of life we often ignore because it's gross and there's not much we can do about it. Every now and then, it pops up in the news and we have to face up to the fact that swimming pools are full of other people's pee. Even Olympic athletes are guilty of relieving themselves mid-swim.
This time, it's a paper from the Centers for Disease Control and Prevention (CDC) published in last week's edition of the cheerily named Morbidity and Mortality Weekly Report. Here, they outline an investigation into an anonymous Ohio indoor waterpark. It was reported to the state's municipal health department in 2015 by staff and guests who developed eye, nose, and respiratory problems after visiting the park.
The health department set up an online survey. Of those who responded, 68 percent (19 people in total) said they'd experienced "eye burning, nose irritation, difficulty breathing, and vomiting," according to the survey. Employees of the water park were four times as likely to develop work-related symptoms than those from other areas of the resort.
But pee was only half of the problem here. When urine combines with chlorine, it forms byproducts called chloramines. The same reaction occurs when chlorine mixes with other nitrogen-containing substances, like sweat, skin cells, sunscreens, and other skincare products.
These chloramines are what likely caused employees and visitors to the park to develop these irritations, and poor ventilation allowed them to build up.
"Improperly functioning ventilation systems, resulting in accumulation of disinfection byproducts and temperature below and relative humidity above recommended ranges, likely contributed to the higher prevalence of symptoms among waterpark employees compared with non-waterpark employees," the paper's authors write.
If you visit an indoor water swimming pool and start to notice eye, nose, or respiratory irritations, the CDC recommends you report symptoms to your local health authority. It could be a sign that more attention needs to be paid to the pool's water quality and ventilation system.
The CDC also advises showering before your swim and taking regular bathroom breaks to avoid contaminating the water. For more info on how to stay healthy in the pool, check out the CDC's guide.
Finally, it goes without saying, but please, please, please try not to pee in the pool.