March 1, 2017 3:46 pm
Updated: March 1, 2017 11:15 pm

How much pee is in the pool? New Alberta research measures water ‘sweetness’

WATCH ABOVE: Some researchers from the University of Alberta decided to look into how much urine ends up in swimming pools. Su-Ling Goh reports on what they discovered.


Nineteen per cent of adults have peed in a pool, according to a 2012 survey of Americans. Now, new research from the University of Alberta shows how all that urine adds up.

Environmental toxicology expert Xing-Fang Li and colleagues figured out a way to measure the concentration of urine in pools – by how sweet the water is.

Acesulfame potassium (Ace) is a common artificial sweetener found in sodas, baked goods and even other sweeteners. Human bodies can’t break it down, so it passes through to urine.

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Li and the team found Ace in all 31 pools and hot tubs that they tested. Only trace amounts of Ace were found in the tap water that filled those pools.

“Even though urinating in pools is quite a taboo, clearly people must be doing it for this artificial sweetener to be present,” said Lindsay Blackstock, a PhD student in Analytical and Environmental Toxicology.

Based on the concentrations of Ace, the researchers calculated a 110,000-gallon pool would contain at least seven gallons of urine.

That’s enough to fill a medium-sized trash bin.

A 220,000-gallon pool (one-third the size of an Olympic pool) would contain 20 gallons of urine. (About three trash bins.)

READ MORE: Why you really shouldn’t pee in the pool 

Not only is that gross, it’s potentially harmful.

Urine (and sweat) react with chlorine to form disinfection byproducts like trichloramine. The compound can cause eye irritation and respiratory problems.

Despite the findings, Blackstock said she still swims in public pools all the time.

“We really want to emphasize that the benefits of a healthy lifestyle maintained through swimming far outweigh any potential risks,” said Blackstock.

The team tested 31 pools and hot tubs in two Canadian cities between May and August 2014. The study included one private pool, and more than one salt water pool.

© 2017 Global News, a division of Corus Entertainment Inc.

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