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In the Swim of Things

How to avoid the enviro nasties that lurk in pools

29 Jul 2003


Let water sit around for 24 hours -- stagnating in an old tire, say, or in a birdbath in the backyard -- and some pretty nasty things can start breeding in it. After Mt. St. Helen's erupted in Washington State in 1980, newly formed oxygen-deprived pools became breeding grounds for Legionnaires' disease. Then there's cholera, typhoid, dysentery, and other illnesses that can be contracted from untreated bathing and drinking water. Yet, while swimming in a bacteria- and pathogen-filled pool poses clear health threats, chlorine is not a risk-free solution.

Some very harmful substances -- dioxins and furans, for example, and also trihalomethanes -- can form when chlorine products come in contact with carbon-containing organic matter, such as leaves and dirt. Dioxins and furans are extremely toxic and are among the "dirty dozen" chemicals targeted for elimination in the 2001 Convention on Persistent Organic Pollutants. Some studies suggest that trihalomethanes, which include the carcinogen chloroform, may cause miscarriages, birth defects, and bladder and rectal cancers.

Both chlorine and chloroform may be found in chlorinated pools and can be inhaled or absorbed through the skin. Too much chlorine in a pool also can cause skin irritation, eye irritation, and both short and longer-term respiratory problems, such as coughing, difficulty breathing, and "swimmer's asthma." In fact, in a study published this June in the Journal of Occupational and Environmental Medicine, Belgian researchers found that young swimmers had high levels of proteins that destroy cellular barriers in the lungs, making them more susceptible to the allergens that can cause asthma attacks. The trigger for these proteins seems to be nitrogen trichloride, a gas released during the interaction between chlorine and ammonia or ammonium compounds from urine, sweat, and other organic sources.

More disturbing still, the researchers found that the children who swam most frequently had levels of these proteins similar to those found in regular smokers. The study concluded that regular swimming in chlorinated pools by young children resulted in an increased risk of developing asthma. The authors also suspect a link to the rising incidence of childhood asthma and allergic diseases found in industrialized nations.

But folks concerned about their health needn't abandon swimming altogether. Here are some suggestions for healthier pool maintenance and safer swimming habits:










A printer-friendly version of an article from: Grist Magazine: Environmental news and humor

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