Have you ever jumped straight into a swimming pool and had chlorine immediately start burning your eyes and nostrils? Of course you have, we all have, except for the fact that it may not actually be just the chlorine that’s causing the stinging sensation, but also urine. Yes, urine.
A study conducted in Canada concluded that the average swimming pool has around 20 gallons of pee in it. Authors of the study tested 31 pools and hot tubs in two Canadian cities, measuring the concentration of the artificial sweetener acesulframe potassium (ACE), a common additive in processed food which passes through the body completely unchanged.
Authors of the study found ACE present in every single sample at concentrations of up to 570 times that of which is found in tap water. Using these figures, they were able to estimate how much of the water in a swimming pool was actually pee, however, the researchers did not monitor the amount of pool users each week.
Whether they’ll admit it or not, most people have discretely peed in a pool at some stage in their life. Prior to the 2012 London Olympics, Michael Phelps claimed it was completely acceptable among swimmers. “I think everybody pees in the pool,” Phelps said. “Chlorine kills it, so it’s not bad.” Ryan Lochte added, “I think there’s just something about getting into chlorine water that you just automatically go.”
But is taking a leak in the pool as harmless as Michael Phelps believes? Apparently not. According to a 2014 study published in Environmental Science & Technology, when uric acid in human urine mixes with chlorine, a toxic compound called cyanogen chloride (CNCI) and trichloramine (NCl3) is formed. Both of these can harm the lungs and CNCI also has an effect on the nervous system and heart, as well.
But what about the eyes and nose? It turns out that urine also reacts with disinfectants to form byproducts called DBPs and these are what irritate the eyes and respiratory system, giving you the red eyes and stinging nostrils. Even worse, some people exposed to DBPs constantly, such as pool employees and professional swimmers, have also developed asthma too.
So get out of the pool and take that bathroom break in the future.