Peter Papachronopolous Guest Writer

“Of course serious swimmers know how dangerous chlorine is. It’s a risk we take,” said Kristen Klein ’08, a member of the College’s varsity women’s swim team. “I’ve never met anyone on any swim team who doesn’t know all about swimmer’s asthma.”

Klein, like most, knows chlorine has been used to disinfect swimming pools for decades. However, recent research of this powerful sanitizer published in the American Journal of Public Healh has raised serious concerns regarding its effect on the human body. Particularly troubling is information related to chlorine’s effects on competitive swimmers, those most exposed to its hazardous effects.

Chlorine is dangerous enough in moderate amounts, but many swimmers are actually exposed to more of the chemical than they need to be. This over exposure is due to the common procedure of pool over-chlorination. Since chlorine evaporates rapidly from water, pool managers often chlorinate pools excessively to ensure enough of the disinfectant is always present. This leads to intolerably high levels of chlorine in pool water and hastens the chemical’s detrimental effects on the human body.

Of the many illnesses that occur in people who swim in over-chlorinated pools, the most frequent is “swimmer’s asthma.” This startlingly common respiratory problem is caused by chlorine inhalation. As the chemical evaporates, it remains heavily concentrated as vapor above the surface of the pool. Competitive swimmers are more likely to experience illness due to chlorine inhalation since they take in more air above the pool surface than casual swimmers do.

“Recently a bunch of us were eating lunch after practice, and someone told a really funny joke. We all started laughing really hard, and, no lie, almost every single one of us started hacking and coughing after a few seconds,” Klein said of the women’s swim team.

The original belief was that those with respiratory problems chose swimming over other sports since swimming is known to relieve asthmatic symptoms. However, now it is clear that the opposite is true; those who swim are developing lung problems due to the dangerous over-exposure to chlorine vapor.

Further, “asthma” is now considered to be an incorrect term for this respiratory problem, which is actually a condition brought on by environment-specific toxic reactions. In studies, those who reported to have breathing problems while swimming suffered no respiratory problems while performing equally strenuous exercise, such as sprinting.

Though many are lesser known, other illnesses also arise from overexposure to chlorine. One of these illnesses is dental enamel corrosion. When continuously exposed to highly acidic pool water, tooth enamel begins to break down. Unfortunately, dentists often misdiagnose this corrosion, associating it with other causes, such as over-consumption of soda.

The most frightening illness that excessive exposure to chlorine can cause is the least reported one. A heightened risk of melanoma, or skin cancer, has been linked to swimmers who routinely use over-chlorinated pools. Not only is chlorine inhaled while swimming, it is also absorbed through the skin as well. Researchers fear that several chemicals formed as by-products of chlorine are carcinogenic, and that these chemicals can rise to dangerously high levels in the body with frequent exposure to the skin.

When asked about the risks of dental enamel corrosion and melanoma associated with over-exposure to chlorine, Klein said, “I knew about how chlorine breaks down your teeth, but I never heard of a skin cancer risk.”

The human body is able to purify itself of a toxic buildup of chlorine, but this process takes at least 24 hours. Unfortunately, many competitive swimmers train two or more times a day. Because of this, their bodies are unable to purge chlorine toxins before they are exposed to them again.

Pool structure plays a crucial role in combating the dangerous effects of chlorine inhalation. If constructed properly, facilities housing pools can sharply reduce the ill effects of chlorine. Ideally, pool facilities should have high ceilings and circulation systems that allow fresh air into the building and force chlorine-saturated air out. Also, pools themselves should not have high walls, which trap chlorine vapor at the surface of the water.

“I really am impressed with the Vassar pool building.” said Klein. “It has really high ceilings and, from what I can tell, a really good ventilation system.” Although she added that she wasn’t sure if the air was simply re-circulated or if fresh air was brought in from outside.

Many methods of pool sanitization are currently being researched as alternatives to the exclusive use of chlorine. Some of these methods have proved effective enough to be implemented in several parts of the world.

For example, in England, the state government of New South Wales has adopted a policy to use Oxone and ionization techniques for all water treatment. In effect, this policy has caused the sole use of chlorine to be outlawed. Oxone is a combination of several powerful oxidizers that disinfect water, though not as effectively as chlorine. When used in conjunction with copper and silver electrolytes, however, Oxone is comparable to chlorine as a disinfectant. A small amount of chlorine is still used to “burn out” any remaining bacteria and maintain a blue color in pool water.

Other techniques being researched involve the use of oxone, hydrogen peroxide, ultraviolet light, and any combination of the three in conjunction with greatly reduced amounts of chlorine.

For more information on the dangers of pool over-chlorination, consult the essay “Swimmer’s Asthma,” posted at :
http://www.rohan.sdsu.edu/dept/coachsci/swimming/chlorine/asthma.htm.
This article owes much of its information to the essay.