Witch's brew found in human tissue
McClatchy News Service - December 10, 2006
By SCOTT STREATER -
FORT WORTH, Texas — They're found in floor waxes and shampoos, fast-food wrappers and microwave popcorn bags. They coat pizza boxes, carpets and frying pans.
And they're in people.
They're perfluorochemicals. While you may not recognize the word, you probably know the brand names: Teflon, Stainmaster, Gore-Tex.
You are exposed to those compounds every day, and there is mounting concern that they may cause a variety of health problems. A panel of scientists selected by the Environmental Protection Agency concluded this year that a perfluorochemical used in nonstick cookware is a likely cancer-causing agent.
As is the case with many of the 82,000 chemicals in commercial use today, health officials aren't sure what levels of perfluorochemicals in the body can cause health problems. Researchers aren't even sure of the main source of human exposure: household products, manufacturing plants or both.
They know only that perfluorochemicals remain in the environment and the body for a long time.
"These compounds are used in an unbelievable number of products that we come in contact with every day," said Kurunthachalam Kannan, a scientist at the New York State Department of Health, in Albany, who has extensively researched the compounds.
Researchers have found that U.S. residents have the world's highest levels of perfluorochemicals in their bodies. Kannan says it takes the body at least eight years to rid itself of the chemicals.
In January, DuPont and other companies volunteered to phase out perfluorooctanoic acid, or PFOA, used in Teflon nonstick
cookware and some microwave popcorn bags.
But there's evidence that neither compound breaks down in the environment — ever. That means people could be exposed for an
untold amount of time.
The Fort Worth Star-Telegram tested the blood of 12 people for the presence of PFOS and PFOA, along with dozens of other
toxic chemicals. The study found PFOS in all 12 participants and PFOA in six.
The concentrations were tiny — parts per billion. One part per billion is equivalent to one kernel of corn in a 45-foot silo filled to the brim. Yet one study published last year in the peer-reviewed journal "Toxicological Sciences" found that PFOA hurt the livers of laboratory rats at low levels.
The highest level of PFOA found in any of the Star-Telegram study participants was 5 parts per billion.
The chemical that makes nonstick cookware slick is in the national spotlight now.
DuPont, based in Wilmington, Del., is North America's only producer of PFOA and faces numerous lawsuits tied to the compound.
In 2004, DuPont agreed to pay up to $343 million to settle a class-action suit filed by Ohio and West Virginia residents who said their water supplies had been contaminated with PFOA from DuPont's plant in Parkersburg, W.Va.
A similar federal lawsuit was filed in April by New Jersey residents who contend that a DuPont plant in Salem County, N.J., contaminated drinking water supplies and that the company knew of the contamination for years.
The PFOA levels in those cases are much higher than what would be expected from products.
DuPont faces a federal class-action lawsuit brought by residents in 20 states and the District of Columbia who say the company failed to make public the possible health risks associated with use of its nonstick pots and pans. The lawsuit, filed in May in Iowa, alleges that DuPont knew its Teflon cookware releases toxic gases when heated.
DuPont denies the allegations.
Last year, the EPA fined DuPont $10.25 million — the largest civil penalty in the agency's 36-year history — for failing to report that it had learned as early as 1981 that PFOA could pass from a woman's blood to her fetus.
Researchers at Johns Hopkins Hospital in Baltimore said in February that blood samples from the umbilical cords of 298 newborns had trace levels of the compound.
"We're not only looking at the levels, but we're also trying to understand whether there are potential health effects or biological markers, biological changes that might be indicative of a biological effect," said Dr. Lynn Goldman, a researcher at the Johns Hopkins Bloomberg School of Public Health who helped lead the study.
Under mounting public pressure, DuPont and seven other companies worldwide agreed in January to stop manufacturing and using PFOA by 2015.
"The fact that it's out there in the blood of the population raises questions that need to be answered," said David Boothe, global business manager for DuPont Fluoroproducts.
But the company vigorously defends the use of the chemical and products that contain it, saying it is "not toxic by the yardsticks that the government usually measures these things."
A number of independent health studies dispute that.
The EPA's science advisory board that recommended that PFOA be considered a likely carcinogen has also proposed that the agency study PFOA's potential to cause liver, testicular, pancreatic and breast cancers and whether it affects the hormones or nervous or immune systems.
DuPont rejects the panel's review because it is based primarily on animal testing.
"We think the weight of evidence and science says, look, the things that are happening in rats don't happen in people," Boothe said.
He also said the EPA has ignored company studies that did not find health problems in workers "exposed to thousands of times higher levels than in the general population."
"So DuPont's position on this is, to date, there are no known health effects from exposure to PFOA," Boothe said.
But the company's worker studies "have many limitations, such that definitive conclusions about PFOA cannot be made at this time," Charles Auer, director of the EPA's Office of Pollution Prevention & Toxics, wrote in an e-mail response to written questions.
There's nothing wrong with using animal studies to gauge health effects of chemicals, said Linda Birnbaum, an EPA toxicologist.
"People are animals," she said. "If you find a similar kind of response in a couple of species of animals or if you find that a chemical is targeting multiple kinds of tissues, why would we think that humans would be completely resistant or different?"
Researchers know that PFOA is widespread in the environment, but how did it get there?
DuPont has spent millions of dollars on studies that it says show that the compound is not coming off nonstick pots and pans.
Independent researchers say small levels do come off the pans but not enough to explain the widespread exposures that have been measured.
Today, the focus has shifted to food wrappers, carpet and other household products. Kannan, the New York State Department of Health scientist, believes that perfluorochemicals are released as a gas off those items.
"They are constantly leaching from the surfaces they are applied to," he said. "The indoor air is filled with these compounds."
They can also be released from manufacturing plants. That's one reason that the EPA pledged in January to add PFOA to a program that tracks industrial emissions of toxic chemicals.
The voluntary withdrawal will help slow the spread of PFOA. But the deadline is not until 2015, which the EPA has classified as an "aspirational goal," not a mandate.
That concerns some researchers who want to see regulatory action taken now, even if a lot more research is needed to determine precise human health effects.
"I think you want to take regulatory action at a point before there are effects in humans," said Goldman, of Johns Hopkins. "The point is to try and prevent that."
There are over 8000 perfluorinated compounds manufactured today...
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