According to a 2009 survey, 1 in 5 American adults admits to urinating in swimming pools. It goes without saying that "peeing in the pool" is not exactly the most hygienic habit, but according to new research, it may pose more serious health risks than you think.

The study, recently published in the journal Environmental Science & Technology, finds that uric acid in urine generates "volatile disinfection byproducts" in swimming pools as it interacts with chlorine, and these byproducts could be harmful to our health.

Of course, the reason swimming pools contain chlorine is for hygiene purposes - to stop microorganisms from developing. But with chlorination comes the development of disinfection byproducts, some of which include cyanogen chloride (CNCI) and trichloramine (NCI3).

Past research has shown that when urine and sweat come into contact with chlorine in indoor swimming pools, this can lead to the development of certain airborne contaminants.

Uric acid in urine leads to formation of CNCI and NCI3

To investigate further, the researchers analyzed swimming pool water samples and looked closely at how uric acid and other body fluids react with chlorine. They used a technique called "membrane introduction mass spectrometry" to find and measure volatile disinfection byproducts.

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1 in 5 of us pees in the pool. Now, researchers have found that uric acid in urine leads to the formation of potentially hazardous volatile disinfection byproducts when it interacts with chlorine.

The findings revealed that when uric acid from urine interacts with chlorine, it can lead to the formation of CNCI and NCI3.

CNCI is a toxic chemical that is known to have strong irritant and choking effects. Inhalation of this chemical can cause negative effects for the cardiovascular system, the pulmonary system and the central nervous system, and can potentially be fatal.

NCI3 is a compound that has been linked to acute lung injury through exposure to chlorine-based disinfectants.

According to the researchers, their findings suggest that more than 90% of uric acid found in swimming pools comes from human urine, which is concerning given that uric acid can lead to the formation of such toxic compounds.

Better pool hygiene needed

Ernest R. Blatchley III, a professor of civil engineering at Purdue University in West Lafayette, IN, says the team's findings show that pool water and air chemistry could significantly benefit from improved hygiene habits of swimmers.

He adds:

"A common misconception within the swimming community is that urination in pools is an acceptable practice, although signs and placards are posted in many pools to encourage proper hygiene.

It is also well known that many swimmers ignore these warnings, particularly noteworthy among these are competitive swimmers."

And it seems Blatchley is not wrong. In a 2009 survey from the Centers for Disease Control and Prevention (CDC) and the Water Quality and Health Council, only 36% of people surveyed said water cleanliness is their top priority when heading to the pool. Furthermore, 63% of participants said they were unaware of illnesses associated with swallowing, breathing or coming into contact with contaminated pool water.

According to the CDC, there has been an increase in the number of recreational water illness (RWI) outbreaks over the past 2 decades.

The most commonly reported RWI is diarrhea, caused by bacteria such as E. Coli and Cryptosporidium. Last year, Medical News Today reported on a study from the CDC revealing that E. Coli is present in more than half of all public swimming pools in the US.

The CDC say that one of the best ways to protect yourself and others from becoming ill from swimming pools is to "keep the poop, germs and pee out of the water."

They recommend that you:

  • Do not swim when you have diarrhea
  • Shower with soap prior to swimming and have rinse showers before getting back into the water
  • Take bathroom breaks every 60 minutes, and
  • Wash your hands after using the toilet or changing diapers.