We've all done it. The game of Marco Polo was heating up and simply exiting the pool to relieve yourself was not an option. To me, there's only one clear solution as a little kid — pee in the pool. And if you are appalled and haven't done it, let me tell you that all of your friends were probably using the same strategy and you had no idea. Even Olympic swimmers aren't afraid to admit it to contributing countless amount of urine in the pool.
It turns out that there is an estimated average of 30 to 80 mL of urine for every swimmer that jumps into the pool. Some of this may be accidental and the individual may not even realize (so for all of the deniers, I beg to differ). Aside from it appearing a little disturbing, is this amount of urine in the pool harmful?
Urine Can Form By-Products
The nitrogen in your urine can actually interact with the chemical disinfectants (think: chlorine) to create by-products that are potentially harmful. These by-products are what give indoor pools their distinct odor and, on a more serious note, may cause respiratory issues.
How It's Measured
In order to track the amount of urine in both pools and hot-tubs to assure safe swimming conditions for all participants, scientists searched for chemical markers that can be used for measurement. Acesulfame-K, an artificial sweetener commonly found in many beverages and baked goods, has been decided to do the trick.
The sweetener cannot be metabolized by humans, meaning it is excreted completely intact. Scientists took litmus paper to 31 community pools and hot tubs in 2 Canadian cities, and compared the findings to tap water. The results revealed that the pool and hot tub concentrations of acesulfame-K ranged anywhere from 30 ng/L to 7,110 ng/L, compared to 15 ng/L for standard tap water.
Going even further, the researchers used the average amount of acesulfame-K found in a person's urine sample to estimate that around 30 liters of urine comprise a 420,000 liter pool.
Am I Safe to Swim?
I'm sure this ratio may be creating a little hesitation for the next time you cannonball into the deep-end. This study tested various public swimming pools in 3 of Spain's major cities for disinfectant by-products and found that the pool water was comparable to standard drinking water.
Still, next time you find yourself in this particular situation, maybe do the right thing and excuse yourself to the locker room. Not all heroes wear capes, some just choose not to pee in the pool.