Public swimming pools are gross— this is known. Swimming in one is basically like taking a soapless bath with a dozen strangers, some of whom are secretly peeing in the water, all of whom are shedding fragments of skin and hair. Most people hop into the pool without any regard for whether or not they're reasonably clean; I once saw a girl full-on blow her nose into a pool, then continue flopping around on her pool noodle as if nothing had happened.
So what's floating around in that water, besides sweat and snot and pee? Researchers from Purdue University, the Georgia Institute for Technology, and the Chinese Academy of Sciences sought to find out by testing water samples from public swimming pools in Georgia and Indiana. In their samples, they found the presence of DEET (the chemical commonly used in insect repellant), TCEP (a type of flame retardant), and caffeine. There were also traces of pharmaceutical drugs like ibuprofen, naproxen, and acetaminophen floating around. (These findings were published in the journal for Environmental Science and Technology Letters.)
So how the fuck does all of that get into the pool? Some of the chemicals—like the insect repellant—come from people's skin, which is why you should all rinse yourselves off before taking a dip. Others, like the drugs and caffeine, are secreted through swimmers' sweat and urine. The researchers had no idea why there was TCEP in their water samples. Maybe someone had been doused with flame retardant before jumping into the pool?
The Purdue study noted that most swimming pools in the United States recycle their water through a closed-loop system, so the same water can stay in a pool for weeks, months, or even years. Years. And although there's chlorine to kill off most of the germs in the water, the chemicals found leftover in swimming pools still survive because they react slowly with chlorine.
If you swim in pools, you may end up swallowing water, which means not only ingesting traces of sweat and urine but possibly gulping down DEET or TCEP as well. Maybe just take a bath instead?
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