Here’s the thing. One-piece bathing suits, when wet, are very annoying to take off. And when you’re swimming three hours a day, as I did for practice on my high school swim team, climbing out of the pool, taking it off, and putting it back on every time you have to use the bathroom starts to feel burdensome. So maybe you just… go…somewhere in between the one millionth and one millionth and first lap you’ve swum that day.
Urine is sterile, and chlorine is sterilizing, right? This is the justification we offered ourselves, to counter our shame. Plus, decorated Olympic swimmers Michael Phelps and Ryan Lochte do it.
Turns out that was a pretty bad idea, for more reasons than just the ick factor. A new study published in the American Chemical Society’s journal Environmental Science & Technology, looked at the chemistry of what happens when urine meets chlorine, and it isn’t pretty.
The researchers mixed uric acid, found in both urine and sweat, with chlorine. Within an hour, they found that both trichloramine and cyanogen chloride had formed. These two chemicals are frequently found in chlorinated swimming pools—Ernest Blatchley III, one of the study’s authors, says that in the nearly 10 years he and his team have been studying swimming pool chemistry, they have found those two chemicals in every sample they’ve taken from a pool.