A Safer Splash

Whether you’re diving into a pool or wading into a lake, certain water conditions can threaten your health. Here’s how to avoid trouble.

A Safer Splash

Sharks in the water! Chlorine that seals your contact lenses to your eyes! Antibiotic-resistant bacteria on the beaches! When it comes to recreational swimming, it can be tough to differentiate between overblown fears and more common (and manageable) health hazards.

Swimming is one of summer’s best-loved activities, providing ample fitness benefits in the company of friends — yet it often provokes anxiety. And the truth is, swimming does carry some risks: Open water can carry viral infections from sewage; chlorinated pool water can provoke asthma; and cloudy lakes may contain cyanobacteria, known to carry neurotoxins and cause disease. But with a little awareness, these hazards can be negotiated. By staying alert to red flags and following some simple safety guidelines, recreational swimmers can splash around safely.

Concern: Bacterial and Viral Infections

Source: Oceans, rivers, lakes, pools and hot tubs. In natural bodies of water and outdoor pools, bacterial and viral infections, otherwise known as recreational water illnesses (RWIs), often come from pollution delivered by sewage or rainwater runoff. In indoor pools or crowded beaches, infections may come from other swimmers.

Symptoms: A wide variety of skin, ear, eye and respiratory issues. Gastrointestinal problems, including diarrheal illnesses, are caused by organisms ranging from Crypto (short for Cryptosporidium) and giardia to shigella and E. coli. “Viruses are assumed to be the cause of most waterborne illness, but the specific virus that causes an illness is usually unknown,” says John Wathen, a beach water expert with the U.S. Environmental Protection Agency (EPA) in Washington, D.C.

Avoiding risk: According to David Beckman, director of the Water Program at the Natural Resources Defense Council (NRDC), beachgoers can reduce their chances of getting sick by swimming only at sites where authorities test the water frequently and close the beach or issue an advisory when it is polluted. Healthy strategies include staying out of the water when there are closings or advisories, avoiding swimming near discharge pipes, and keeping dry if you have an open wound. Wathen recommends avoiding beaches for a couple of days after a heavy rain and staying attuned to murky water or foul smells. Indoors or out, make sure that your pool water is properly and adequately treated with an anticontaminant.

Following exposure: Rinse off well. Clean skin abrasions. Dry out your ears. Take a shower and wash swimsuits and towels as soon as possible.

Concern: Chlorine

Source: Swimming pools and hot tubs.

Symptoms: Skin irritation, wheezing, coughing, throat burning, stinging eyes or shortness of breath. Chlorine reacts with organic compounds in various ways that release both waterborne and airborne toxins. In recent studies of children and teens, Alfred Bernard, a toxicologist at the Catholic University of Louvain in Brussels, found that chloramines and haloacetic acids released by chlorine are five times more likely than secondhand smoke to exacerbate symptoms of asthma and respiratory allergies in those already at risk for these conditions.

Avoiding risk: Steer clear of overchlorinated swimming pools (chlorine between 2 and 5 parts per million is considered safe for most). When in doubt, ask pool managers to check the levels of active and combined chlorine in pool water or air. You might also seek out pools treated with alternative disinfectants like copper-silver or ozone, although these may not be ideal for avoiding all RWIs.

Following exposure: If your time in the pool has produced asthma or allergies, treat yourself as you would following any other precipitating cause. Above all, do not go back into the water until you are symptom-free — and limit your time in the pool to minutes, not hours, a day.

Concern: Neurotoxins

Source: In oceans, rivers, lakes and ponds, blue-green cyanobacteria can accumulate when exposed to runoff from phosphorus fertilizer or paper mills, sometimes becoming so dense they coat the water with a green slime.

Symptoms: Some species of cyanobacteria release a neurotoxin so potent that chronic exposure is starting to be traced to neurodegenerative diseases like Parkinson’s and ALS, according to Dartmouth-Hitchcock Medical Center neurologist Elijah Stommel, MD, PhD. Far more common, he says, is brief, acute exposure, which can result in anything from itching and skin rash to illnesses of the GI tract and liver.

Avoiding risk: Stay out of dark or murky waters. “If you see green fluorescent scum on the surface of a pond, don’t go in,” advises Stommel. The smell of rotting eggs may be another sign of cyanobacteria in the water.

Following exposure: As with exposure to RWIs, take a shower and wash swimsuits and towels as soon as you can.


Guide to Water Quality Online

Before you go swimming, make sure your local beach, lake, river or pool area is monitored.

For links to water reports and some of the best how-to's, check out: www.cdc.gov/healthyswimming/swimmer_protection.htm — The CDC’s tips for preventing recreational water illnesses.

www.epa.gov/waterscience/beaches — The EPA’s Beaches Environmental Assessment and Coastal Health (BEACH) Program offers information about the quality of the water on our nation’s beaches.

www.epa.gov/NHEERL/neear — The National Epidemiological and Environmental Assessment of Recreational (NEEAR) Water Study is a collaboration between two laboratories of the U.S. Environmental Protection Agency and the Centers for Disease Control and Prevention. Researchers are investigating human health effects and rapid water-quality methods associated with recreational water use.

www.nrdc.org/water/oceans/gttw.asp — The National Natural Resources Defense Council offers tips on how to check the safety of your favorite beach before you head out for a swim.

www.who.int/water_sanitation_health/bathing/srwe1/en — In its Guidelines for Safe Recreational Water Environments, the World Health Organization describes swimming water safety and risks around the globe.

Pool and Hot-Tub Water-Quality Tips

Before you get into a pool or hot tub, according to the CDC, you should:

  • Make sure it’s clean and clear. You should be able to clearly see the bottom of the pool.
  • Check to see that it has smooth sides; tiles should be neither sticky nor slippery.
  • A strong chemical smell may indicate a maintenance problem — a well-chlorinated pool has little odor.
  • Make certain the equipment is in working order; pool pumps and filtration systems make noise and you should hear them running.
  • Check chlorine levels yourself by purchasing test strips at a home-improvement or pool-supply store. (Note: Chlorine should be 2 to 5 parts per million and pH should be 7.2 to 7.8.

Red Tide Rising

If you’re swimming in the waters of the Gulf of Mexico from Florida to Texas, stay alert to signs of red tide — blooms of microscopic marine algae named Karenia brevis, known for producing the powerful brevetoxins, lethal to fish and other marine life. If you see red or rust-colored blooms in the water, do not go in. If you find yourself suddenly immersed in a red tide, stay calm. Brief exposure may result in rash or respiratory irritation, including coughing, sneezing and tearing, but the impact will be temporary. Just get out of the water and rinse off as soon as you can.

is a senior editor at Discover magazine and author of Cure Unknown: Inside the Lyme Epidemic (St. Martin’s Press, 2008).

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