There’s a sweet new way to test a pool for pee (and it turns out, there’s a lot)

There’s an artificial sweetener called acesulfame potassium (ACE) that you can find in processed foods and drinks. Turns out, it can also be found in public pools.

Researchers at the University of Alberta have estimated the amount of urine in 31 public pools by measuring the amount of ACE in them. Their technique is one commonly used to study the impact of human waste on environmental water sources. The synthetic sweetener is a perfect marker for the presence of urine, because our body is unable to break down the compound — we excrete 100 percent of the amount we ingest. It also remains stable over many years and under a variety of temperatures. The only reason it would be in pools or hot tubs is because — you guessed it — people peed in them.

The study, published in the journal Environmental Science and Technology Letters, found that in a 110,000-gallon pool, swimmers released about seven gallons of urine — about enough to fill a large trash can. A 220,000-gallon pool contained almost 20 gallons.  

Urine in public pools is not just a frightening fact, it’s also a public health concern. It can interact with chlorine to create a chemical called tri-chloramine, which irritates the eyes and has been linked to occupational asthma in professional swimmers.

Lindsay Blackstock, a Ph.D. student at the University of Alberta and first author on the paper, joins Ira to discuss her sweet finding.