A new study has found a way to measure the amount of urine in public swimming pools. Researchers from the University of Alberta have found that in a pool of 833,000 liters – which is one-third the size of an Olympic pool – there was 75 liters of urine. That tallies up to be the equivalent of 20 large milk jugs. A second swimming pool that was tested was half the size and found to have 26.5 liters of urine in its water.
The team collected water samples from swimming pools and hot tubs at various hotels and recreation facilities in two Canadian cities. They measured the amount of urine by determining the levels of a sweetener called acesulfame potassium or Ace-K. This sweetener is found in a majority of foods from yogurt to soup and does not readily break down in pool water.
Study co-author Lindsay Blackstock, a PhD student of analytical and environmental toxicology says, “Even though no one would admit to peeing in a pool, obviously somebody has to be doing it. There is no other explanation for that (substance) to be present in the pools.”
The sharp smell of chlorine that is often detected in public water facilities is the result of chemicals that form from chlorine mixing with body oil, sweat and urine. Aside from being unpleasant, high levels of urine can be a potential health hazard. When chlorine reacts with urine it forms a host of potentially toxic compounds called disinfection byproducts.
University researchers point out that this is not about the North American diet and that Ace-K has been detected in people’s urine in China as well, a country that has the same issue with urine in swimming pools.
Ernest Blatchley, an environmental engineer at Purdue University says, “I think you can assume that if people are using your pool, they’re peeing in it.” While no one is suggesting people stop swimming, Blatchley does say that the simplest solution is for people to just stop peeing in pools.
“I view it like second hand smoke,” Blatchley says. “It’s disrespectful and potentially dangerous.” He adds that once pee becomes present in a pool, the only way to get rid of it is to replace the water.
“It’s not uncommon for water in a pool to go unchanged for years,” he says, since many pool owners add water as needed however, the longer water sits in a pool the worse it gets. His own research has shown that over time as people add more chemicals to the water (rather than replace it), the old water converts to form chloride that encourages the formation of more disinfection byproducts.
The study was published in Environmental Science & Technology Letters.