A study that highlights the health risks of urine in swimming pools has received a flurry of media attention — much of it leaving out an important point about the data.
In March, the journal Environmental Science & Technology released a study suggesting the introduction of urine in chlorinated pool water could contribute to the respiratory health issues that have been connected to indoor pools.
The study hit the press with alarming headlines such as, “Peeing in The Pool May Cause Heart, Lung Problems,”; “Urinating in the Swimming Pool Could Result in a Deadly Chemical Weapon”; and “Some People Pee in the Pool — and It’s Hurting Our Health.”
However, virtually every news report failed to mention that the findings were mostly relevant to indoor pools. This is an important distinction because airborne compounds generally can dissipate naturally when a pool is outdoors. “If a pool’s giving off chloroform and it’s outdoors … it doesn’t matter,” said Bill Peck, owner of William Peck Pool Services in Poway, Calif. “But indoors you’ve got the stale air. The circulation isn’t nearly as good.”
Others are concerned that such emphasis on a danger that is still somewhat theoretical might remove attention from drowning prevention and even make some people reluctant to swim.
“The people who don’t want to go in pools already, it’s just going to reinforce their perception of them as being dangerous …,” Peck said. “People who already swim aren’t going to care.”
Others believe the industry already has enough tough press to deal with, considering the coverage of the Virginia Graeme Baker Pool and Spa Safety Act and other safety issues. “The industry doesn’t need any more stories making the consumer afraid of having a swimming pool or of owning a pool,” said Gina Schrader, vice president of Patio Pools in Tampa, Fla.
In publishing the study, it wasn’t the intent to scare people away from pools and swimming, said one of its authors, Ernest R. Blatchley III, a professor of civil engineering and environmental and ecological engineering at Purdue University.
“I’m a former swimmer, and I don’t want to do anything to discourage swimming,” he said. “I want to make sure that the environment is as healthy as it can be.”
The study by Blatchley, Lushi Lian, Yue E and Jing Li looked at how uric acid and chlorine react to form byproducts.
Uric acid is present in urine and sweat, but the concentration is several hundred times higher in urine. While studies had addressed the effects of other substances in pool water, there hasn’t been one to assess the byproducts that result when uric acid is introduced to chlorine, Blatchley said.
The scientists conducted two types of experiments. The first was completed in a laboratory under controlled conditions. Here, they added uric acid and chlorine to clean water in doses similar to what they hypothesized would be seen in a pool. By withholding the myriad other substances normally found in pool water, scientists could isolate the reaction between chlorine and uric acid and study it in detail.
The second method involved collecting water samples from public pools and observing it two ways — one as it was straight from the pool, the other with uric acid added. “By doing that both with and without uric acid … we can see how much the uric acid contributes to the formation of these various disinfection byproducts,” Blatchley said.
The authors placed 370 micrograms of uric acid per liter of pool water. It isn’t really known how much uric acid the typical pool contains, since it depends on how many bathers there are and the pool’s water capacity. Previous studies have shown, however, that swimmers release an average of 1 to 3 ounces of urine each.
The authors said the experiments showed uric acid, when combined with chlorine, efficiently contribute to the formation of cyanogen chloride (CNCl) and trichloramine (NCl3), the nitrogen-containing byproducts that can have negative health effects when inhaled. NCL3 has been linked to lung injury, while CNCl is toxic and can affect organs such as the lungs, heart and central nervous system. The authors also said the addition of uric acid to chlorine may be a significant contributor to the formation of CNCl in pools.
While the study doesn’t serve as proof positive that urinating in pools can be harmful to one’s health, it does demonstrate the possibility, Blatchley said.
Some believe it has significance. “I think it’s likely that urination in pools is the biggest preventable contributor to poor water quality and poor air quality,” said Thomas Lachocki, Ph.D., who is CEO of the National Swimming Pool Foundation in Colorado Springs, Colo. “Anything we do to improve [the situation] is smart for our customers and smart for business.”
The NSPF provided a grant for the study, but wasn’t the only financial supporter.
It’s long been known that children are prone to urinating in pools, and competitive swimmers have received attention on the subject in the past couple of years. In 2012, swimming champions Michael Phelps and Ryan Lochte were widely derided for publicly stating that they urinate while training, and that the practice was common. Many have criticized competitive swimming for creating a culture where this is acceptable.
Some in the aquatics community believe that coaches should mandate breaks for swimmers to use the restroom. Additionally, facilities could schedule short “adult swims,” which would encourage children to leave the pool and give them an opportunity to use the restroom, Lachocki said. The issue also can be considered while designing aquatics facilities by placing restrooms for convenient access. To that end, the current draft of the federal Model Aquatic Heath Code stipulates that restrooms must be 200 to 300 feet from the pool.