Peeing in Swimming Pools: Chemicals and Health Hazards
The Problem With Peeing in Pools
Many people reading this article wouldn't dream of peeing in a swimming pool. According to a recent report published in an American Chemical Society journal, however, it's happening often enough to create a health hazard in some pools. Members of the general public and elite swimmers alike have admitted to peeing during swims. Some elite swimmers urinate in pool water frequently. There is evidence that urine is also being released into hot tub water.
The problem with peeing in a swimming pool or hot tub is not the release of bacteria. Although urine isn't sterile (despite a rumour to the contrary), it generally contains a low level of microbes. In addition, the water in pools and tubs usually contains disinfectants that kill bacteria and other microbes. Unfortunately, chemicals in urine react with the disinfectants to create potentially harmful products.
Experimental Evidence for Urination in Swimming Pools
In a recent investigation, researchers from the University of Alberta in Edmonton collected water samples from pools and hot tubs in two Canadian cities. They tested the urine for the presence of acesulfame potassium, also known as acesulfame K or ACE. The chemical is a common artificial sweetener in soft drinks and processed food. It's even used as an ingredient in other sugar substitutes. It passes through the body and into the urine without being altered.
The researchers tested a total of 250 water samples from 31 pools and hot tubs. They also tested 90 samples of the tap water used to fill the pools and tubs. They discovered that ACE was present in every sample that they tested. They also found that the chemical was up to 570 times more concentrated in the pool and hot tub water than in tap water. Since ACE is not deliberately added to swimming pools or hot tubs and is excreted in human urine, the investigators concluded that people had urinated in the water.
The reason why a small amount of acesulfame K was found in tap water is due to its stability. Most of the chemical survives wastewater treatment. It has been found in groundwater and enters tap water, although not in sufficient quantities to make the water taste sweet.
Lest readers get the impression that only Canadians like to pee in pools, it should be noted that peeing in swimming pools is common in elite U.S. swimmers.
Elite U.S. Swimmers Pee in the Pool
Urine contains nitrogenous waste products, including urea, uric acid, ammonia, and creatine. It has been known for some time that these react with chlorine-based disinfectants in pool water to form disinfection by-products, or DBPs. Bromine, ozone, and ultraviolet radiation are also used to disinfect the water, either on their own or in combination with another technique. This can cause the production of other by-products.
Hundreds of different DBPs can form in and around swimming pools, but some are more common than others. The chemicals are produced not only from the components of urine but also from chemicals in sweat, personal care products, dirt, dead cells, and hair. In addition, they are made from the remains of medications that have entered the urine. I've chosen three common DBPs to discuss in this article.
Disinfection by-products are present in treated tap water, including the water used to fill swimming pools. They make a relatively minor contribution to the DBP level in swimming pools, however.
One of the most common and annoying disinfection by-products is trichloramine, also known as nitrogen trichloride. Its chemical formula is NCl3. The chemical can cause eye and skin irritation as well as respiratory problems, including asthma. This can be true even when the chemical is at usual pool concentrations and gets worse as the concentration increases. Trichloramine is responsible for the typical swimming pool smell, which is often wrongly attributed to chlorine.
Although DBPs are often dangerous when they are in a concentrated form, they are safer at the low concentrations present in swimming pools. Pure trichloramine is an explosive substance. This isn't true for the chemical when it's present in pool water, however.
It's Not Okay to Pee in the Pool
Cyanogen chloride or CNCl is another common disinfection by-product. It can be deadly when it's concentrated. Like other DBPs it has a relatively low concentration in and around pool water, however. People don't drop dead after inhaling or swallowing it when they visit a swimming pool. Nevertheless, the chemical is of concern.
Like trichloramine, cyanogen chloride is a volatile substance (one that readily turns into a gas). The concentrated chemical causes severe irritation of the eyes, skin, and airways and interferes with the body's ability to use oxygen. It can also cause fluid buildup in the lungs (edema), convulsions, loss of consciousness, and death.
It's uncertain whether DBPs in pool water are sufficiently concentrated to cause any serious health effects. There are preliminary indications that some of them may be, but the discoveries need to be confirmed.
Chloroform or CHCl3 is yet another common DBP. Once again, it's a volatile chemical that is normally present at a low concentration in and around swimming pools but is of some concern.
The concentrated chemical irritates the eyes and skin. It also depresses the activity of the central nervous system and can cause a coma. It was once used as an anesthetic but was dangerous because it can trigger a deadly alteration in the rhythm of the heartbeat. Doctors also found it hard to control the dose. Concentrated chloroform inhaled over a long period damages the liver and kidneys. The chemical is a suspected carcinogen (a substance that causes cancer).
Public Health Recommendations
Swimming in a pool is fun and can be great exercise. It's not necessary to avoid the fun or the exercise unless the disinfection by-products are too irritating for a swim or unless the pool maintenance program is of concern. I think that it's the responsibility of swimmers to follow public health recommendations, however, for the sake of themselves and of other swimmers. Many of these recommendations are listed below.
- Shower with soap before entering a pool to remove sweat, personal care products, dead cells, and fecal matter from the skin. Feces can transmit disease.
- Don't enter the water if you have diarrhea or an intestinal infection. Small quantities of feces and urine can be released into the water accidentally.
- Don't swallow pool water and try to avoid getting it in your mouth.
- Make sure that indoor pools have good air circulation, since many DBPs are volatile and enter the air as a gas.
- Use the restroom whenever the urge to pee appears.
- Make sure that children urinate in the restroom before entering the water and that they leave the water whenever they need to "go".
- If children mention peeing in the pool, explain that this is not a game and that it can affect the health of other people.
- Make sure that babies wear good swim diapers. These retain solid feces, but unfortunately they don't retain liquids.
- Shower after a swim to remove contaminants.
Untreated water can accumulate harmful Escherichia coli and Salmonella bacteria and protozoans such as Cryptosporidium parvum and Giardia lamblia.— Chemical and Engineering News Magazine
Managing Pool Water
Pool managers have a difficult but very important task. They must add enough disinfectant to the water to kill microbes and keep people safe but not so much that disinfection by-products become dangerous. The choice of disinfectant is also important. Chlorine, sodium hypochlorite, and calcium hypochlorite disinfectants form hypochlorous acid in water. The acid destroys many pathogens (microbes that cause disease), but not all of them. For this reason a chlorine-based disinfectant is often combined with another type.
A small amount of new water is generally added to a pool every day in order to replace the water lost by evaporation and other activities. The American Chemical Society says that it takes about a hundred days to completely replace the water in an average swimming pool. This give DBPs time to accumulate.
The public can help the situation by reducing their contribution to by-product production. Some production of the chemicals is inevitable, since we release urea in our perspiration as we exercise. By avoiding voluntary urine release we can keep the pool environment healthier and more pleasant for everyone, however.
American Chemical Society. (2017, March 1). How to monitor urine in pools, by testing sweetness. ScienceDaily. Retrieved August 6, 2017 from www.sciencedaily.com/releases/2017/03/170301084913.htm
Chemical reactions in swimming pools from Chemical and Engineering News, an American Chemical Society publication
Questions & Answers
© 2017 Linda Crampton