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Bottled Water: FAQ on Safety and Purity

Questions and Answers on Bottled Water and How It Compares to Tap Water

Is it safe to drink old bottled water?

The FDA considers bottled water to have an "indefinite safety shelf life" if it is unopened and properly sealed, but drinking water quality expert Rolf Halden, PhD, of Arizona State University is not so sure.

"Even water stored for emergency use should be replaced periodically," he tells WebMD. "You wouldn't want to keep it for 10 years."

Can chemicals leach from plastic bottles and pose a health risk?

Most experts who spoke to WebMD say there is little to worry about.

The major concerns have involved the chemicals bisphenol A and phthalates.

Bisphenol A is used in the production of multiuse polycarbonate water bottles, but not in single-use bottles used by commercial bottlers.

Likewise, phthalates are not typically found in plastic beverage bottles used commercially in the U.S. But Janssen says phthalates have been found in bottled water, suggesting that it may leach from the plastic cap or liner.

"These chemicals may be in your water, but you would never know because the water companies are not required to test for them," she says.

Is freezing bottled water or leaving it in a hot car dangerous?

Both of these concerns have circulated widely in emails and on the Internet. One email that has been around for several years warns that freezing bottled water leads to contamination with carcinogenic dioxins.

The email was erroneously attributed to Johns Hopkins University, and it was so widespread that Johns Hopkins' scientists felt compelled to publicly set the record straight in a news release.

Rolf Halden, PhD, PE, who is an adjunct associate professor with the Johns Hopkins Center for Water and Health, called the claim "urban legend."

He notes that there are no dioxins in plastics and that freezing actually slows or prevents the release of chemicals.

The industry group representing single-use beverage bottle manufacturers, known as NAPCOR also used the term "urban legend" to describe claims that it is unsafe to drink water that has been left in a hot car.

"The idea that (these) bottles 'leach' chemicals when heated in hot cars is not based on any science, and is unsubstantiated by any credible evidence," the group noted in a recent news release. "This allegation has been perpetuated by emails until it has become an urban legend, but it just isn't so."

Is there fluoride in bottled water?

If it is added by the bottler, the label must say so. But most bottled waters probably don't have as much fluoride as fluoridated tap water.

The CDC has stated that most bottled waters contain fluoride at levels that are less than optimal for oral health. It weighed in on the issue in a news release last February.

"If you mainly drink bottled water with no or low fluoride and you are not getting enough fluoride from other sources, you may get more cavities than you would if fluoridated tap water were your main water source," the statement noted.

The CDC also warns that preparing infant formula with fluoridated bottled water could cause dental fluorosis, a condition in which permanent white spots occur on the teeth.


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