New tests for artificial sweetener could soon help determine how much pee is in public hot tubs and pools.
Although the researchers were unable to confirm exactly what fraction of visitors were choosing to quietly relieve themselves in the water rather than making the shivery trip to the changing rooms, the results suggest that the urine content was being topped up several times each day.
They found that a typical commercial-size swimming pool holding 220,000 gallons will have about 20 gallons of urine, and a small residential 20 by 40 foot pool that is five feet deep will have about two gallons of human waste.
ResearchGate: What motivated this study?
Calorie-free, artificial sweeteners aren't metabolized in the body-they go in, and they come out unscathed.
"Even though no one would admit to peeing in a pool, obviously somebody has to be doing it", said one of the researchers, Lindsay Blackstock, a PhD student of analytical and environmental toxicology at Alberta University.
The researchers couldn't actually measure urine as that breaks down in chlorine, but they can measure acesulfame-K (ACE). ACE is commonly added to many prepackaged foods and is therefore consumed widely among the general public. ACE is consistently present in the urine, chemically stable and remains unaltered after passing through the body.
Currently, there is no way to test for urine in pools, according to Live Science. Nevertheless, it's enough to be a health concern, and to give off that pool-y, pee-y smell.
So, in light of the recent research, you might want to think twice before going to a public pool.
Using these results, the scientists approximated the amount of human urine present in an average swimming pool.
Sure, pee is sterile, but its chemicals can react with the pool water to form so-called "disinfectant byproducts", or DBPs. And people like professional swimmers and pool workers have reported asthma that's been linked to their long time spent in the pool, according to the researchers. One way of looking at this is that the urine amounted to around 0.009 and 0.007 percent of the total pool water, respectively.
RG: Why is it so hard to monitor the amount of urine in pools?
One regular-sized community pool contained 75 litres of pee, while in a single child size pool there were 30 litres of the yellow stuff. Nitrogen in pools can be hard to monitor, because it can react with disinfectants to form volatile compounds that can escape into the air where they can no longer be measured in a pool water sample.