Hot Liquid Ups BPA From Plastic Bottles
Study: Chemical Released More Quickly With Boiling Liquids; Risk to People Not Clear
By
Salynn Boyles
WebMD Health News
Reviewed By
Louise Chang, MD
Jan. 30, 2008 -- Pouring boiling liquid into reusable water bottles or baby
bottles made of polycarbonate plastic causes a much faster release of the
estrogen-mimicking chemical bisphenol A, new research shows.
University of Cincinnati researchers reported that exposure to boiling water
caused polycarbonate drinking bottles to release bisphenol A (BPA) up to 55
times more rapidly than exposure to cool or temperate water.
The jury is still out on whether BPA exposure poses a health risk to humans,
even though the question was the subject of two expert panel reviews in the
U.S. last year.
More than 6 billion pounds of bisphenol A are produced and used each year in
the manufacture of the resins used to line food cans and in polycarbonate
products. Almost everyone has measurable amounts of the man-made chemical in
their blood, the CDC says.
It has long been known that BPA can cause genetic damage in lab animals, but
it is not clear if the levels of leached BPA from polycarbonate bottles and
other products are high enough to pose a threat to humans.
BPA at High Temperatures
Scott M. Belcher, PhD, who led the study team, tells WebMD that while there
is little direct evidence that BPA poses a risk to humans, many experts believe
that it does.
"The consensus of the scientific community is that there is a clear
reason to proceed cautiously," he says.
But Steven G. Hentges, PhD, who is executive director of the American
Chemical Council's Polycarbonate/BPA Global Group, disagrees.
Hentges tells WebMD that the finding that BPA leaching accelerates at high
liquid temperatures is nothing new, having been reported in numerous previous
studies.
"The bisphenol A levels seen under heating conditions are still
extraordinarily low and far below levels that have been determined to be safe
by government bodies," he says.
The popularity of reusable, plastic polycarbonate drinking bottles has grown
with rising concerns about the environmental impact of disposable plastic
bottles.
Plastic water and soda bottles manufactured for one-time use are not made
with polycarbonate plastic. But many baby bottles and those hard water bottles
sold in outdoor and athletic stores are.
Same Levels in New and Old Bottles
Belcher collected used polycarbonate water bottles from his local climbing
gym and purchased new ones from a nearby outdoor activities store.
All the bottles were subjected to seven days of testing designed to simulate
normal use during backpacking and camping conditions.
Whether they were new or used, the bottles released the same average amount
of bisphenol A at the same rate when exposed to cool or temperate water.
"There is some thinking that the longer a bottle is used the more BPA it
releases, but that isn't what we found," Belcher says.
But much higher levels of bisphenol A were released when the bottles were
briefly exposed to boiling water. The rate of release after exposure to boiling
water ranged from 8 to 32 nanograms per hour, compared with a range of 0.2 to
0.8 nanograms per hour under room-temperature conditions.
And the speed of release was 15 to 55 times faster, Belcher says.
He adds that the findings have made him reassess his own habits.
"I don't put hot tea or hot water in these bottles when I'm climbing
anymore," he says. "And I have retired my polycarbonate French-press
coffeemaker."
What the Experts Say
The two expert panels that recently weighed in on the safety of bisphenol A
reached different conclusions.
The National Toxicology Program's Center for the Evaluation of Risks to
Human Reproduction (CERHR) convened a 12-member panel made up of government and
non-government scientists to review the scientific evidence.
The group concluded that bisphenol A exposure levels for most Americans were
well within the Environmental Protection Agency's standards and found no major
health risks associated with exposure.
The panel did express "some concern" that the chemical could cause
behavioral and neurological problems in developing fetuses and young children,
however.
Another panel made up of 38 researchers who have studied BPA concluded that
levels of the chemical seen in humans are higher than those that caused adverse
effects in animal studies.
The group also expressed confidence that even low doses of BPA can have
biological effects.
Belcher, who served on the latter panel, says the group concluded that there
was good reason for concern that bisphenol A can cause harm to humans at
routine exposure levels.
Hentges says the panel was far from objective and their findings contradict
those of other experts around the world.
"The very extensive research that has been done supports the safety of
bisphenol A," he says. "That is the consensus of experts worldwide who
have no stake in this."
SOURCES: Scott M. Belcher, PhD, department of pharmacology and cell biophysics, University of Cincinnati College of Medicine. WebMD Health News: "Jury Still Out on BPA/Plastics Risk." National Institute of Environmental Health Sciences: "Questions and Answers about the CERHR Bisphenol A Report."
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