When the summer turns the city to sweat and frustration, those public swimming pools we overlook most of the year, suddenly become nothing short of enticing. But before you dive in, think carefully about the long-term effects of pool managers' chlorine addiction.
A new study out of Belgium suggests regular use of indoor pools is associated with a higher risk of childhood asthma. Apparently the toxic chemicals produced when chlorine contacts sweat or urine damage the deep lining of the lungs, causing irritation and greater vulnerability to allergens.
The researchers don't believe they've proven anything yet and say more study is needed--but if respiratory problems run in your family, some experts suggest you might want to monitor your breathing and your kids' breathing carefully during and after a swim in indoor chlorinated waters. (The researchers didn't look at the impact of swimming in outdoor pools.)
Of course fumes aren't the only acquatic hazard. If you're the type who filters your shower water because of chemical hazards, you may not want regular lengthy immersion in pool water either. The exact extent of the cancer risk posed by chlorine compounds is a matter of tremendous debate and the studies done tend to focus on drinking water. This is a case where a clear assessment of risk isn't yet possible.
And remember that there really are infectious bugs in that lovely green shared water. Chlorine is used precisely because of its lethal powers. Without enough of some form of anti-infection agent, toxic compound levels rise. Even technologically advanced pools that use ozone gas or ultraviolet light disinfection still need some degree of chlorine to nab germs as they're introduced by swimmers.
In the meantime, what's a hot city dweller to do? Use outdoor pools when you can, to take advantage of natural ventilation. If chlorine severely bothers you, check with pool management to find out if they'd be willing to use bromine, a less dangerous disinfectant chemical. Take a shower before you swim to lessen the amount of reactive body fluids and cosmetic products you introduce into the pool. Don't swallow the water. If you've got upset stomach, diarrhea, a plantar's wart, or a sore, open wound, or infection, stay on land till you're healed.
"As part of the whole inspection our inspectors look at the chlorine levels in the pool. Sometimes bromine is used. It has less of a toxicity profile than does chlorine. The regulations that we use are provincial. There is a minimum standard for chlorine and bromine, but no maximum. There is no particular air quality measurement that is done routinely. The only reference to air quality in our regulations is about the air in the change rooms, washrooms, and showers.'
KARL KABASELE, MD, Associate Medical Officer of Health, Toronto Public Health
"Nike, one of our members, uses an ozone process for purifying their pools. Ozone is a free radical molecule that wants to combine (with other forms of oxygen to create stable molecules) and destroys everything in its path to do that: microbes and pollutants. Ozone dissipates before it becomes part of humans. It is extremely cost effective. Europeans are doing their best to get away from chlorine and that has a lot to do with (WW11) history. There are some sanitizing chemicals out there that can meet the requirements for pool disinfection. Grapefruit seed extract does a very good job, but may never be approved (in the U.S.) due to political reasons."
ARCHIE BEATON, Executive Director, Chlorine Free Products Association
"It has been known for quite a while that chemicals used to clean swimming pool water can trigger symptoms in some people who have asthma, but what we need more information on is how asthma is caused, not how it's triggered. If you have asthma and are severely affected by pools, you may have to avoid them. If you're mildly affected you may be able to control it through other means. You have to weigh the benefits of exercise against the possible risk to your lungs. At this point it's too early to say that you shouldn't be sending kids without asthma to pools, because they get so many benefits from that.'
CHRIS HAROMY, Respiratory Therapist, Certified Asthma Educator
"The Belgian study) was very exploratory research and the researchers themselves didn't draw any firm conclusions. This study was looking at chloramines (chlorine plus ammonia) and they are irritants. Maintaining proper levels of chlorine will reduce levels of chloramines. That's very important and is completely lost on the authors of this study. I would hate to focus on speculative risks (such as those raised in the study) when there are very real risks from microbial outbreaks. We need to focus on actions that will bring about the greatest public health benefits.'
JEFF SLOAN, Director of Disinfection Policy, Chlorine Chemistry Council, Arlington, VA
"Ultraviolet light technology can be used to assist in keeping pools clean. It cannot be relied on to do it by itself because it doesn't leave a residual killing mechanism in the water. In a swimming pool you've got lots of people, and there's those accidents that happen, and then (without chlorine) you've got a catastrophe on your hands. You need a residual killing element in the pool. Actual deaths have occurred because of swimming pools where people have put in kids who have pooped. You can probably reduce chlorine need by 50 to 70 percent by installing a UV system. The water turnover rate required with UV alone would be so high you couldn't afford the pumping costs and the pool would be in constant turmoil all the time."
RICH COMBS, Vice-President, Sales and Marketing, Trojan Technologies London, ON