HEALTH
You know that sharp odor of chlorine from the swimming pool? Turns out it’s not just chlorine, but a potent brew of chemicals that form when chlorine meets sweat, body oils, and urine. (NPR)
Hold your nose and take a look at some cool pools!
Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.
Photograph by Howell Walker, National Geographic
Image courtesy Xing Fang-Li et. al, http://dx.doi.org/10.1021/acs.estlett.7b00043 Environmental Science & Technology Letters “Sweetened Swimming Pools and Hot Tubs”
Discussion Ideas
- How can scientists tell how much urine is in a swimming pool or hot tub? Take a look at the title of the study that details the procedure for some help.
- Chemists measure the amount of artificial sweeteners in the pool to determine how much urine is present. “Certain sweeteners can be a good proxy for pee,” according to NPR, “because they’re designed to ‘go right through you’ and don’t break down readily in pool water.”
- Specifically, scientists studied a sweetener called acesulfame potassium, or Ace-K. Acesulfame K is extremely stable, allowing it to be used as a food additive in baked goods and products that require a long shelf life. “It’s found in everything from yogurt to soup these days, so it’s no surprise that it’s ubiquitous in our urine.”
- Scientists calculated that a commercial-sized swimming pool had about 20 gallons of urine, and a residential pool had about 2 gallons. Dive in!
- Chemists measure the amount of artificial sweeteners in the pool to determine how much urine is present. “Certain sweeteners can be a good proxy for pee,” according to NPR, “because they’re designed to ‘go right through you’ and don’t break down readily in pool water.”
- “I think you can assume that if people are using your pool, they’re peeing in it,” says an environmental engineer. Apart from being gross, that’s also a potential health hazard. Why?
- Chlorine, used as a sanitation agent in most swimming pools and hot tubs, interacts with urine, sweat, or body oils to form toxic chemicals called “disinfection byproducts.”
- Chloramines, one type of disinfection byproduct, are common drinking water disinfectants and generally not harmful to people not suffering from asthma or other respiratory illnesses.
- Nitrosamine, another disinfection byproduct, is carcinogenic—although there is little evidence the levels of nitrosamines in swimming pools correlate to higher cancer rates.
- Cyanogen chloride, another disinfection byproduct, is classified as an agent in chemical warfare. It interferes with the body’s ability to use oxygen.
- Chlorine, used as a sanitation agent in most swimming pools and hot tubs, interacts with urine, sweat, or body oils to form toxic chemicals called “disinfection byproducts.”
- Why are indoor pools potentially more of a health hazard than outdoor pools?
- Indoor pools allow for less air dispersal; disinfection byproducts can accumulate in the air above the pool.
- Indoor pools have less sunlight, which naturally neutralizes some disinfection byproducts.
- How can swimmers avoid a build-up of harmful disinfection byproducts? Take a look at this guide from the CDC for some help.
- Make sure the water in the pool is changed regularly. The longer water sits in a pool, the more disinfection byproducts accumulate. Simply adding more chlorine might make the problem worse.
- Make sure to shower before getting in the pool. Just a one-minute rinse can remove much of the sweat and body oils that react with chlorine.
- DON’T PEE IN THE POOL!
TEACHERS TOOLKIT
NPR: Just How Much Pee Is In That Pool?
Nat Geo: Awesome 8 Cool Pools photo gallery
CDC: Steps of Healthy Swimming
(extra credit!) Environmental Science & Technology Letters: Sweetened Swimming Pools and Hot Tubs
Well.. It’s going to take me a while to think about stepping into a pool again