Audrain County Health Department
Public Health: Better Health, Better Missouri.

Pool-Related Safety & Illnesses

Although  urine itself is sterile,  its presence  in swimming  pools  is a  public health concern because urine can mix
with pool chemicals to create compounds that harm swimmers' health.  These compounds can reach concentrations
detrimental to health and these health risks start with a little chemistry:

•        Urine is made up of tons of different substances, all of which can interact with chlorine.
•        But, uric acid and a handful of amino acids pose the biggest threat.
•        When each of these react with chlorine, the compounds they create are:
   1.        Trichloramine (aka nitrogen trichloride) & Cyanogen Chloride.
   2.        Both can be harmful in high enough concentrations.

The problem is that it`s incredibly difficult to determine just how concentrated these chemicals are in pool water at
any given time.  This is because it depends on numerous factors, such as:

1.        How many people are using the pool;
2.        How well mixed it is;
3.        How warm the water is;
4.        How long it’s been since the water has been changed.

The amount of trichloramine can be measured, but the tools used aren’t generally available at pools.  And cyanogen
chloride is even  harder  to  measure because it’s a very dynamic chemical that forms and decays very rapidly and is  
quite volatile.   Of the two substances, cyanogen chloride is the most concerning.  It’s a toxic substance, and once it
reaches a  high enough level,  it can be detrimental to human health.   But the problem is that because it forms and
decays so quickly, it’s very hard to figure out how high those levels get in a pool.  

Trichloramine can cause respiratory problems when inhaled or absorbed through the skin, especially in those who  
have illnesses, like asthma.   It also causes irritation to one’s lungs,  skin,  and eyes  &  creates that sometimes
overwhelming pool smell, & makes your eyes burn. Cyanogen chloride is an irritant too, & can affect the body's
ability to use oxygen.    A whiff of the stuff in the pool isn’t fatal, but breathing it in definitely isn't good for you.  

In most swimming pools,  the levels of cyanogen chloride won’t reach toxic levels.    However, there are certain
conditions    it can accumulate to unacceptably high concentrations; such as in a really crowded pool.  Any pool
that you put people in, you can count on people peeing in it. Based on a multitude of studies, the average swimmer
leaves behind about 50-80 milliliters of urine.  Even though it’s shocking, the average public pool can have as much
as 30-75 liters, or 8-30 gallons of urine in it.

If everyone is peeing, most people ask why we don’t just chlorinate our pools more? Chlorine doesn’t kill urine,
and it’s not the solution because the more chlorine you add, the more likely the chemical reactions that create those
volatile compounds will occur. Instead, we should be working to disband the current culture that it’s okay to urinate
in the pool.  That summertime pool smell is urine.

So, what can we do?

•    Recognize some people treat a pool as a cleaning opportunity - take a shower before getting in the pool.  
•    Try and urinate before getting in the pool.
•    Step out to the restroom if you need to urinate.
•    Empty & refill the pool if high concentrations or WBI reports exist in a public pool.  Ozone destroys pathogens.
•    If we can stop the culture of routinely urinating in pools, we can cut down on our chlorine usage— that would  
reduce the burden of organic compounds that react with chlorine, which would, in turn, result in less chlorine
usage as well as improved water and air quality.

Audrain County Health Department - 1130 South Elmwood, Mexico, MO. 573-581-1332