Science Scene: Peeing in the pool is an act of chemical warfare

Ellen Airhart

UT students will have to make a choice when nature calls at Gregory pool this summer: walk across the carpeted door mat to be blasted with air conditioning while dripping, miserable and distracted from the fun — or engage in chemical warfare.

What these happy swimmers don’t know is peeing in the pool isn’t just gross, but by continuing their laps with only a twinge of guilt for subjecting fellow swimmers to the same stuff as their toilet bowl, they are creating harmful chemical substances once used in WWI for chemical warfare.

One in five adults admits to peeing in the pool, according to a study by the Water Quality and Health Counsel. In an interview with The Telegraph, Olympic athletes Michael Phelps and Ryan Lochte admitted to peeing in the pool. According to Madisyn Cox, a UT swimmer and neuroscience junior, competitive swimmers don’t have the option of getting out of the pool every time they need to use the restroom.

“Everybody pees in the pool,” Cox said. “At this level, it’s absolutely everyone.”

Disinfection byproducts, or DBPs, are formed when disinfectants, such as chlorine, and natural organic matter, such as urine, combine in water. Swimming pools have high levels of DBPs because of the combination of the chlorine used to sanitize the pool and people who ooze organic matter such as skin cells, sweat and urine.

Two noteworthy DBPs form when a swimmer urinates in the pool. The pee’s uric acid and chlorine form two substances called cyanogen chloride, CNCl, and trichloramine, NCl3, according to a 2014 study in the journal Environmental Science and Technology. The same study stated although uric acid is also present in sweat, 93 percent of the uric acid in the pool comes from urine.

In 1993, the Chemical Weapons Convention classified CNCl, a lung irritant, as an agent of chemical warfare. But years before, during WWI, the French used CNCI to infiltrate gas masks. As soldiers began to face difficulty breathing, they would remove their masks, which then exposed them to other poisons that are deadly in smaller doses. NCl3 were never used in battle but cause similar symptoms.

In large doses, CNCl results in deadly symptoms, including fluid-filled lungs, seizures, reduced circulation, coma and even death. CNCl is classified as a blood agent, which means the bloodstream absorbs and spreads it throughout the body. Blood agents cause symptoms quickly — CNCl can kill in under eight hours in large enough doses. NCl3 can irritate the mucous membranes in the eyes, nose and throat, which causes difficulty breathing and headaches.

Fortunately, there is not nearly enough pee or chlorine in any pool to cause death or immediately dangerous symptoms. There is still ongoing debate among scientists about how much damage these amounts cause. In small doses, CNCl and NCl3 are still eye, skin and respiratory irritants, adding to the irritation chlorine already causes. Scientists have found links between cyanol chloride and trichloramines and respiratory diseases such as asthma, but these correlations require more study.

There is a way to protect fellow pool goers from the dangers of cyanol chloride and trichloramines. Just don’t pee in the pool.