Feature Article - April 2007
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Risky Business

Critical Safety Issues for Aquatic Facilities

By Joseph Ryan



A long, pool drink

Surprisingly, there have been few scientific studies on how much water swimmers swallow and whether that amount varies depending on age, gender and habits.

But the value of such data can be tremendous. It can help researchers determine who may be more at risk for a water-borne illness, and it can also help determine the amount of pool-cleaning chemicals that may constitute a health hazard.

Environmental Protection Agency (EPA) microbiologist Alfred Dufour has attempted to fill this void in crucial data, and his latest study may help pool managers understand why clean water is such a priority.

Dufour tested 553 swimmers by measuring the amount of ingested cyanurate, a pool-disinfectant chemical that is not absorbed by the body. The test results were released in his September presentation for the National Swimming Pool Foundation's World Aquatic Health Conference in Austin, Texas.

The test group involved recreational swimmers at both public and private pools, including 145 boys and 99 girls age 6 to 18; 80 men and 96 women age 19 to 40; and 54 men and 79 women age 41 or older. There was a total of 279 males and 274 females, and each participant was asked to swim exactly one hour for the test.

Dufour found that children swallowed nearly twice as much water as adults.

Children under the age of 16 swallowed an average of 1.6 ounces, compared to the adults' average of 0.8 ounces.

"This is the most important finding of this study," Dufour told seminar attendees. "It may tell us why children become ill at much higher frequencies than adults."

Dufour's test also found that among the adults, men swallowed considerably more water than women. The test found male adults accidentally drank an average of about 1 ounce and women swallowed an average of 0.6 ounces.

Dufour attributed this difference to an increase in vigorous swimming, such as laps, by the older males. He believes such pool activity causes people to swallow more water than relaxed swimming. However, Dufour didn't ask the test subjects to document their swimming styles, so a definitive relation between the swimming types and water ingested is not available.

Dufour was also surprised by the great variations in the amount of water subjects ingested. Some subjects ingested almost no water, while others drank as much as 10 ounces.

Requests for data from the new test have been pouring in from aquatic, chemical and risk management experts.

"Even before we were completing this study, we were getting requests," Dufour said.