Jewish World Review
http://www.jewishworldreview.com | (KRT) Something was wrong with the mice eggs.
In two separate labs at Case Western Reserve University, researchers noticed a sudden mini-epidemic of defective chromosomes in August 1998.
And no one could say why.
Was it the food? The water?
Human error in handling the eggs?
After some anxious detective work, with months of valuable research in jeopardy, genetics professor Patricia Hunt made a surprising discovery:
When someone used the wrong soap to clean the plastic mice cages, a chemical - bisphenol-A, the same chemical that is used to make baby bottles, dental sealants, and linings for food and beverage cans - leached out of the plastic.
In the five years since that discovery, industry has continued to make millions of pounds of BPA, even though, the Case Western researchers learned, studies beginning in 1997 had claimed it was linked to problems such as enlarged prostates and decreased fertility.
"The first thing I wanted to do was go down to my kitchen and throw out every bit of plastic I had in my house," Hunt said. "I thought, `What is this stuff still doing on the market?' "
The U.S. system of regulating chemicals, which allows many substances to be used in everyday products without first testing them in a lab for safety, is under scrutiny as the European Commission voted last Wednesday to adopt much tougher regulations.
The European rules would require testing of at least 10,000 chemicals already on the market, and lesser amounts of data on 20,000 more. Officials already have drawn up lists of chemicals they want to tackle first because of their wide use - among them bisphenol-A.
BPA is unlike some substances in that it has been highly studied, having been used in plastics for 50 years. Previous studies had shown no apparent health consequences at doses far higher than what Hunt discovered. And the U.S. Food and Drug Administration has declared the substance to be safe.
But Hunt subscribes to a relatively new theory that some chemicals can cause harm at very low doses but not at high doses - a concept popularized by researcher Frederick vom Saal at the University of Missouri.
Upon learning more about the composition of the cages, made by Thoren Caging Systems of Hazleton, Pa., Hunt conducted follow-up studies in which mice were fed very low doses of the substance.
Similar chromosome defects ensued, of the kind that would lead to miscarriages if the eggs were fertilized - although the effect was not as dramatic as with the original mice.
Her findings, published in the April issue of the journal Current Biology, caused a minor uproar.
The low-dose theory is controversial, and industry officials insist it has no basis. Meanwhile, the FDA estimates typical human exposure to be even lower than what the mice encountered: less than one part per billion per day, or one one-hundredth the amount fed to the animals in the follow-up study.
(Missouri's Vom saal says the FDA estimate is out of date and far too low, given the amounts found recently in human blood.)
"BPA is indeed one of the best-tested chemicals around," said Steven G. Hentges, executive director of the polycarbonate business unit of the American Plastics Council. "We're very confident that the existing data show that it is safe for use."
Hentges cited another study that was unable to reproduce Hunt's findings. In that study, unlike Hunt's, the mice eggs were actually fertilized and grown into live animals. Critics say the uncertainty is all the more reason to proceed with caution and conduct more research. They express concern that in the U.S. system of regulating chemicals, evidence of possible harm - such as that from Hunt's lab - is discovered by accident.
"Unfortunately, that's the way we discover things," said Joel Tickner, an occupational health professor at the University of Massachusetts in Lowell. "By chance." Both the FDA, which regulates BPA when it comes into contact with food, and the U.S. Environmental Protection Agency, which regulates its use in other products such as car headlights and compact discs, say they are keeping an eye on research.
George Pauli, the associate director for science and policy at the FDA's Office of Food Additive Safety, said he is not convinced there is risk - for now.
"We're skeptics that some of these animal studies are really reflecting something … that would be of concern for humans under the conditions that humans are exposed to," Pauli said.
However, he added: "It's not something we're just going to ignore."
As for Hunt, she followed through on her initial impulse and got rid of most of the plastic in her kitchen.
Her favorite gift-giving item these days?
Jars and containers made of glass.
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