# How Much Pee is in Your Swimming Pool?

Now that summer is winding down and you’ve already spent lots of time in the water,I want to show you now how to figure out how much pee is in any pool. There’s actually a lot of misinformation on the topic of pee and pools, so I’m gonna do some experiments on my own along with some clever science people in foreign lands and spoiler alert: some of the results are good news and some aren’t, so let’s jump right in.

So this first experiment is to determine how much pee is in an actual sample of pool water using an ingenious method. So I got two samples from my friend’s community pool, where lots of people swim. One from the pool and one from the spa, and then two samples from a friend’s backyard, again one from the pool and one from the spa. I also collected samples from the source water at each location as a control and I’ll explain why in a minute. Now that I have my samples I needed to quickly get to my scientist friend Lindsay in Canada, but lucky for me—-I knew a shortcut.

We are now in the lab of the University of Alberta, and this is Lindsay Blackstock and she is basically a genius. So you are going to help me determine how much pee is in these samples, because we know people pee in the pool. Yes, we have strong evidence that people do pee in the pool. So we’re going to try to find a way that we can measure that pee without actually measuring pee. I’m going to apply my new strategy based on the amount of artificial sweetener that’s in the pool. We know artificial sweeteners don’t come from anywhere except for urine, so that’s the only logical source for them if we find them in the pool,and we know how much artificial sweetener is in the average person’s pee and then using that we can estimate how much pee is in the pool, so we’re going to take this sample,we’re going to bring it over to our sample prep bench, we’re going to filter it, transfer it into some special vials Into this instrument, which is a liquid chromatography system, so this instrument is going to concentrate our sample before it passes it on over to the second instrument,which is a mass spectrometer and the mass spectrometer is able to detect the individual little artificial sweetener molecules one by one. Love it, let’s get to work!

Bring it on over there. Before we run the samples let me explain why I find Lindsay the scientist’s solutions, so brilliant. You can actually take a sample of pool water and directly measure the amount of urea in there,but the problem with that is humans also excrete urea through things like sweat,which is also very common in a pool, so you can’t tell how much of that urea actually came from pee. To get around that she looked at the amount of a certain artificial sweetener in the sample called Acesulfame Potassium, which is really common in food products such as these–oh, and also all of these. So pretty much everything. The reason drinks like these are zero calories is because you taste the Acesulfame Potassium sweetener,but the chemical compounds aren’t broken down at all by your body so more than 99 percent is passed through in your pee,within 24 hours. And therefore the only reason this would be in the pool is if it passed through a person first. And just to be sure you measure the source water at both locations because sometimes trace amounts of the sweetener can be found in the water supply if so we just subtract that from the results.

I love this because we’ve all wondered how much pee is in a specific pool? But Lindsay figured out a really clever way to use proven science to actually answer the question. The mass spectrometer takes about an hour to get results,So while we were waiting,Lindsay told me something that really surprised me. Chlorine in pools is obviously really helpful because it breaks down harmful bacteria,viruses, and microbes that would be harmful or even potentially deadly to humans. However, there is one big downside and that is, it reacts with urine to create a byproduct called trichloramine. So trichloramine is what’s responsible for that chlorine smell that you might get when you enter into an indoor swimming facility It’s also- but if you smell chlorine like straight out the bottle, it has that chlorine smell. Yeah, but but the smell that you smell in a pool is trichloramine, like this is the compound responsible for that characteristic swimming pool smell- if I look skeptical here it’s only because I was; so I devised an experiment of my own to see if this is really true.

For the experiment I got two five-gallon buckets and filled them with pure water,then I added four times the recommended concentration of chlorine for that volume of water to both buckets,and then only in the bucket labeled BI added just a little bit of pee, and I let it sit for a couple days. Alright, so it’s been three days,so this is the moment of truth.  So the first thing I notice is visually, they look the same. You can’t tell one bucket from the other as far as color of water goes. So I’m gonna start and smell this one first. Mmm, so that doesn’t smell like anything, that smells just like water even though this has four times the recommended concentration of chlorine for this volume which makes me nervous to smell this one. What?That is crazy!This smells like a pool even though the only difference between these two is this has a little bit of pee in it. This is a nostalgic smell this smells like summers and vacationing at hotels of pools and water parks,Turns out it was just pee.

So in if trichloramine which again is what is produced when pee reacts with chlorine,was just that classic pool smell that’s not that big of a deal,but the problem is it’s kind of bad news for both your lungs and your eyes. When your eyes are really red after swimming for a while, that’s actually because of the trichloramine from the pee, not the chlorine. Trichloramine also causes things like asthma. In fact studies show asthma is more likely to occur among elite swimmers, than any other high-level athlete, which now makes sense because Michael Phelps admitted to always peeing in the pool, and he says all his buddies do too. So be cool, and don’t pee in the pool. Now let’s go see Lindsay’s results. In Lindsay’s research. She sampled 20 public swimming pools and 10 public hot tubs. The average concentration of sweetener for the pools was 470 nanograms per liter and for the hot tubs was 2,247.