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Don’t Go in the Water: The Chemistry of Pee in the Pool [Video]

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In the summertime, when the weather is fine, you may have swimming on your mind. A swimming pool dip can cool you off. But some other bodily functions may produce unhealthy chemical reactions. Urinating in a chlorinated pool can lead to small amounts of chemicals that might irritate your lungs, according to this new video from Breakthrough Science and the American Chemical Society.

The culprit is uric acid in urine, says chemist Ernest Blatchley of Purdue University, who admits in the video that he has peed in a pool. But he doesn’t anymore, and not just because it is impolite. He and some colleagues discovered that uric acid and chlorine interact to produce small amounts of cyanogen chloride and trichloramine. When inhaled in large volumes these chemicals can damage internal organs. The amount of these chemicals that can be made by the typical amount of urine released by a swimmer–30 to 80 milliliters–is much smaller than anything that has been linked to physical harm, Blatchley hastens to say. But particularly in indoor pools, it is possible they could cause some irritation, he says. He and his colleagues originally reported these results in the journal Environmental Science & Technology.

Peeing in the ocean should be worry-free, however. That’s according to some reporting by Lauren Wolf, an editor at Chemical & Engineering News. Urine, she notes, is largely water and salt–and that happens to be, largely, what seawater is made from. There isn’t anything like chlorine in ocean water to trigger a bad reaction. Plus, she notes, fish and whales are doing a lot of ocean urinating on their own.

Josh Fischman About the Author: Josh is a senior editor at Scientific American, covering biology, chemistry, and earth science. On Twitter, he is @jfischman, and you can email him story ideas at Follow on Twitter @jfischman.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. laurenkwolf 10:03 am 06/11/2014

    Thanks for the shout-out, Josh! I had interviewed Ernest a while back with the intention of writing another blog post in my “pee series.” But of course, I never had time to do it.
    One thing I think news of this research needs to highlight is that we NEED chlorine in pools. Without it, things could go pretty wrong. You DON’T want to see what kind of microbes a public swimming pool could grow without chlorine.
    I would also love to see some follow-up studies on this someday. How much cyanogen chloride and trichloramine are needed to cause chronic respiratory problems in swimmers over time? I think there have been some epidemiology studies done showing a link between asthma and professional swimmers, but you get my point.

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  2. 2. HowardB 10:15 am 06/11/2014

    A questionable ‘research paper’ at best. Full of assertions followed by backtracks.
    Howe does that ‘possible’ irritation compare with inhaling the gas produced as a result of the chlorine added to swimming pools ?

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  3. 3. magneticnorth50 5:53 pm 06/11/2014

    Must be a slow news week huh .If you’re in a public pool , urine is the least of your worries .

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  4. 4. CAVESTEVE 5:57 pm 06/11/2014

    In 1955, Long Beach Polytechnic High School, my swimming coach was also our chemistry teacher. He explained the Chemistry of Chlorine and Pee and illustrated them in Chem- class once. I remember well his admonition, “If your eyes and throat are burning it’s because your class mates are peeing in the pool.”
    He demonstrated that Liquid chlorine added to water, in the right amounts, produces no smell or taste and what we sense are only the reactants and the over use required by the pee load.

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  5. 5. jgrosay 4:40 pm 06/12/2014

    Old joke: a man goes to the swimming pool, the guardian halts him, and states: Mr marquis has access forbidden to swimming pool. ->Hey, I contributed with many of the money for building it, so why? ->mr marquis always pees in the swimming pool. ->everybody pees in the swimming pool…-> yes, but mr marquis pees from on high of the trampoline.

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  6. 6. Edgod1 8:35 pm 06/20/2014

    If you pee in the ocean you may attract sharks, as urine to them is just a blood extract.

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