Marianne Ruegsegger had heard the warnings before.
"I have a friend whose husband is a chemist, and he said
never to heat food in plastic, that the molecules can get
into the food," Ruegsegger said.
Ruegsegger followed that advice, but continued to use her
Tupperware and collection of plastic containers - butter
tubs, yogurt cups and the like - for storage and other
purposes.
Then came the latest warnings: New scientific studies
link bisphenol-a, or BPA, a chemical used in the manufacture
of durable plastic bottles, food-can linings and dental
fillings, with a host of serious maladies.
Ruegsegger, a computer systems analyst who lives in
Escondido, Calif., boxed up her plastic storage tubs and
bought glass containers instead.
"I feel safer now, I think," she said.
If Ruegsegger remains a bit uncertain about the real and
perceived health hazards posed by plastic - specifically by
polycarbonate plastic containing BPA - she is far from
alone. For many consumers, the recent flurry of news reports
about plastics and health hazards has been conflicting and
confusing.
While a growing number of scientists say animal and
cell-culture studies link low-dose BPA exposure to
everything from altered neural development to reproductive
system deformities to cancer, other researchers say the
findings are inconclusive at best, irrelevant and
fear-mongering at worst.
While Canada reportedly is close to declaring BPA to be a
toxic chemical - it would be the first country to do so -
the U.S. Food and Drug Administration says there is no
compelling proof that BPA harms people.
While the chemical industry adamantly, even aggressively,
insists BPA presents no measurable health risk to humans and
cites 50 years of safe use, the marketplace appears to be
abandoning the chemical. Nalgene, the maker of hugely
popular polycarbonate water bottles, has said it will stop
using the plastic because of consumer concerns.
Playtex, which makes baby products containing BPA, says
it will follow suit. Major retailers including Wal-Mart and
Toys "R" Us have announced plans to switch to selling only
BPA-free baby bottles, teething rings and other products.
For the consumer, these contradictory actions are both
encouraging and alarming. Many experts say it is prudent to
reduce, if not avoid, at least some kinds of plastics in
some kinds of situations. But in a world dominated by the
stuff, how practical is that?
COMPOUND INTEREST
Plastic is everywhere and, it seems, in almost every
person. A 2004 survey by the U.S. Centers for Disease
Control and Prevention found traces of bisphenol-a in 93
percent of urine samples tested. Japanese scientists say it
is detectable in the amniotic fluid and umbilical cords of
unborn children.
In April, the National Toxicology Program, part of the
federal National Institute of Environmental Health Sciences,
issued a draft report highlighting research that showed some
lab rats fed or injected with low doses of BPA reached
puberty early, had urinary tract problems or developed
precancerous tumors.
The agency described the evidence as limited but said the
"possibility that bisphenol-a may alter human development
cannot be dismissed."
The chemical industry immediately brushed off the report.
"The findings provide reassurance that consumers can
continue to use products made from bisphenol-a," said Steven
G. Hentges of the American Chemistry Council, an advocacy
group.
The draft report marked the first time that a U.S.
government agency had expressed public concern about
possible health risks posed by BPA.
The final report is not due for a couple of months,
pending public and industry response. A call for further
research is expected.
Research - or perhaps the lack of it - is at the heart of
the conflict and confusion over BPA. The studies suggesting
low-dose BPA exposure provokes adverse responses in cells
and in test animals number in the hundreds.
The problem is that no one can say with certainty that
these findings translate to humans.
"Obviously, this is a situation in which you're never
going to directly test people," said Robert Tukey, a
professor of chemistry and pharmacology at the University of
California San Diego.
Compounding the issue is the question of whether humans
are being exposed to hazardous levels of BPA.
"There's no doubt (BPA) can behave as estrogen mimics,"
said William Trogler, a University of California San Diego
chemistry professor. "The issue is the level of exposure, in
particular what people actually experience. Is the level
significant or not?"
Many studies suggest it is. With improved tools and
techniques, researchers are reporting measurable effects
from BPA at levels well below those declared safe by
government regulators and industry scientists.
Some research indicates humans may be exposed to more BPA
than previously thought - that under certain conditions,
these chemicals leach out of plastic in higher-than-expected
amounts.
For example, a much-reported study this year at the
University of Cincinnati found that polycarbonate baby
bottles exposed to boiling water - meant to simulate
prolonged use and multiple washings - released 55 times more
BPA than bottles exposed only to hot water. Other research
has shown that old, scratched polycarbonate plastic leaches
chemicals more readily than newer material.
The chemical industry counters these reports with other
studies citing no significant adverse effect from BPA.
Industry spokesmen say the government backs up their
position, noting the FDA's announcement last year that it
knew of no research compelling enough to merit restricting
or banning BPA. In March, FDA officials conceded the
conclusion was based on just two industry-funded studies.
To be sure, not every kind of plastic poses a known or
suspected health risk. Polyethylene terephthalate ethylene -
more commonly known as PET or PETE - is widely used in
disposable water, soda and juice bottles. Health experts
generally say it poses no known health threat, particularly
if it is not re-used.
Likewise, high density polyethylene, or HDPE, plastic,
used in milk jugs, shampoo bottles and cleaner containers,
is considered to be safe, as is low-density polyethylene, or
LDPE, used in bin liners and packaging films, and
polypropylene, or PP, used in microwaveable plastics and
straws.
More worrisome are polyvinyl chloride, PVC or V, used in
cling wrap and some plastic squeeze bottles; polystyrene,
used in foam cartons, carryout containers and opaque plastic
cutlery; and BPA-laden polycarbonate plastics, used to
create rigid, shatter-resistant containers, such as
backpacking bottles or baby bottles.
FOREVER PLASTIC
So what's a person to do? Realistically, there probably
is no way to avoid exposure to plastics entirely. They are
part and parcel of modern American life, found in almost
every processed product.
The United States produced 6.5 billion pounds of raw
plastic in December 2007, up 2.3 percent from one year
earlier.
But if plastic is a permanent fixture of life -
decomposition rates range from tens to thousands of years -
experts say there are different ways to think about and deal
with it.
If a particular plastic poses a health risk, it should be
banned, said Sharyle Patton, director of the health and
environmental program at Commonweal, a nonprofit research
institute in Bolinas, Calif., north of San Francisco.
"I don't want to wait for science to tell me a man-made
substance is safe. This can take years," Patton said. "I
want these chemicals out of all of our bodies until we know
much more about what makes us sick and what keeps us well."
Rick Clark, director of medical toxicology at University
of California San Diego Medical Center, said it's not that
simple. If the science isn't conclusive, then other factors
must be considered.
"My job is to decide whether the risk of a little
exposure to a chemical outweighs the benefits of having that
chemical," Clark said.
Clark cited the example of benzene, a known human
carcinogen that people inhale when they pump gas.
"It's in gasoline because there's no way to get it out
100 percent," he said. "So we take precautions to minimize
the health risk, like having those covers on nozzles. The
resulting exposure level isn't believed to be high enough to
cause leukemia, and we accept the risk because we need the
gas."
It's much the same with BPA and other common but possibly
hazardous chemicals, Clark said.
"You try to find and use alternative products if you can,
but ultimately you have to determine your degree of risk,"
he said. "I can't tell you that you're not getting an
exposure from BPA. I can't tell you for certain the chemical
isn't doing something to your body. But the data up to this
point is lacking for me.
"I'm not throwing away my Tupperware yet."
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