Archive for the ‘Bisphenol A (BPA)’ Category

Q & A with Dr. David Feldman

Here’s a Q&A with Dr. David Feldman regarding his accidental discovery in 1993 that BPA leaching from lab flasks caused breast cancer cells he and his team were studying to rapidly multiply. David Feldman, MD, emeritus professor of endocrinology at the Stanford University School of Medicine.

Stanford Q&A: David Feldman on risk of bisphenol A in plastic bottles

STANFORD, Calif. — Bisphenol A, an estrogenlike compound in polycarbonate plastics and epoxy resin, has been popping up in the news a lot lately. On April 18, Canada announced that it would ban baby bottles containing bisphenol A beginning in mid-June. The action would make Canada the first country in the world to set exposure limits on the chemical. In addition, the U.S. National Toxicology Program, which is part of the National Institutes of Health, recently concluded that there is “some concern” that fetuses, infants and children may be harmed by the amounts of bisphenol A that leach out of many brands of baby bottles, hard-plastic water bottles and food cans lined with epoxy resin.

In the early 1990s, David Feldman, MD, emeritus professor of endocrinology at the Stanford University School of Medicine, and his team were the first researchers to identify and call attention to the possible impact of low levels of bisphenol A on human health. In the following Q&A, Feldman talks about his accidental discovery.

Question: How did you first identify bisphenol A?

Feldman: It was basically an accident; we were not looking for it. We study receptors for steroid hormones like estrogen, and wondered if they had originally evolved in yeast. Although that turned out not to be the case, we were looking for both receptors and hormones when we found what looked like an estrogenic molecule in the yeast tissue culture medium we grew the yeast in. However, the medium had been sterilized by autoclaving (a process that involves very high heat and pressure) in “autoclavable” polycarbonate flasks. We identified the estrogenic molecule as BPA using mass spectrometry, and discovered it was present even in samples of pure water that had been autoclaved in the flasks. At that point we realized that we had identified a molecule that was leaching out of the plastic that, because of its estrogenic hormonelike properties, had the potential to be important and perhaps even dangerous to people who were eating or drinking out of containers made of this type of plastic, polycarbonate. Since polycarbonate has so many uses as a clear and strong plastic, it is ubiquitous in packaging food and beverages, and epoxy resin is used in lining metal cans.

Q: What did you do next?

Feldman: We wanted to let people and governmental authorities know what we found. We sent samples to the company that made the polycarbonate flasks to warn them of the problem, but they couldn’t find the bisphenol A. Our biological tests were more sensitive than the tests they were using, which were meant to identify levels of more than 25 to 50 parts per billion. Anything under that amount was considered to be safe. In contrast, we were picking up levels, and seeing estrogenic biological effects, at 5 to 10 parts per billion.

Q: So, were the former regulations wrong? And why has it taken so long—nearly 15 years—to get attention?

Feldman: It’s very difficult to know what “safe” levels are. Although we published our findings in 1993, it was unclear for a long time how much of the bisphenol A was absorbed by humans, how fast it accumulated and even whether or not it was damaging to human health. In fact, to date there have been no studies showing that bisphenol A exposure affects human health. Although subsequent studies have shown that the levels to which humans are exposed do have adverse biological effects in laboratory animals, it would of course be unethical to conduct similar dosing studies in humans.

One thing we do know is that, in the 2003-04 National Health and Nutrition Survey conducted by the Centers for Disease Control, 93 percent of about 2,500 people ages 6 and above had detectable levels of bisphenol A in their urine. So almost everyone is exposed. We also know that bisphenol A is similar in chemical structure to diethylstilbestrol, a synthetic estrogen that has been linked to the development of vaginal cancer and other toxicities in the daughters of women who took the drug during the ’50s and ’60s to prevent miscarriage. So we know that it is possible for some of these synthetic estrogenlike compounds to have bad effects many years after initial exposure. We also need to remember that the effects of these so-called “environmental estrogens” or “endocrine disrupters” are additive. There are many different ways we can be exposed to these various compounds and they are cumulative.

Q: Do you feel it is time for the individual consumer to take protective action?

Feldman: Well, I feel there’s enough evidence to support a “better safe than sorry” approach, particularly for fetuses, infants and children. Not only do they weigh much less than adults, making their relative exposure greater, but they are also still developing estrogen-sensitive breast and prostate tissue. In my opinion, the prudent thing for current or expectant parents or those planning a pregnancy to do would be to limit their child’s exposure to bisphenol A by avoiding bottles and cups that are made of polycarbonate, and to microwave food in glass containers whenever possible. For adults, however, canned foods and beverages may be the most important source of bisphenol A.

Manufacturers are already responding to this change in consumer demand. For example, Nalgene has just announced that it will no longer make reusable drinking containers with plastic containing bisphenol A, and Wal-Mart will no longer sell baby bottles with bisphenol A. Once these major merchants begin demanding bisphenol A-free alternatives, we can hope the use of polycarbonate to package food and beverages will decline.

Q: Have you changed your own habits in the lab or at home because of your bisphenol A findings?

Feldman: Yes, to some extent. I do strongly advise my children to avoid exposing our grandchildren to bisphenol A. I don’t microwave food in plastic containers, or wash the containers in the dishwasher because heat and some detergents cause leaching. I try to limit the amount of canned food I eat, or rinse the food before consuming the contents. Of course, we no longer autoclave laboratory materials in plastic. Overall, it is safest to try to be careful and avoid bisphenol A and other endocrine disrupters.

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The Stanford University School of Medicine consistently ranks among the nation’s top 10 medical schools, integrating research, medical education, patient care and community service. For more news about the school, please visit http://mednews.stanford.edu. The medical school is part of Stanford Medicine, which includes Stanford Hospital & Clinics and Lucile Packard Children’s Hospital. For information about all three, please visit http://stanfordmedicine.org/about/news.html.

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Milwaukee Journal Sentinel’s Watchdog Series “Chemical Fallout”

This is an outstanding series. Here are some of the latest articles in the series. The link below will direct you to the series

Chemical Fallout

Warning: Dangerous chemicals are common in every day products, including food containers. And government has been slow to protect consumers from those dangers. Indeed, in the case of Bisphenol A, federal government regulators long sided with the chemical industry in declaring BPA safe – despite independent studies that repeatedly documented danger to children and adults. The government about-face in January of 2010 came only after years of investigations by the Journal Sentinel. Read original series: Part 1 | 2

The following stories highlight action taken as a result of the Journal Sentinel’s investigation.

FDA does about-face on exposure to BPA
The U.S. Food and Drug Administration on Friday reversed its position on bisphenol A, saying it was concerned about the chemical’s effects on fetuses, infants and children. However, the agency stopped short of a ban, saying more studies are needed. »Read Full Article

REACTION: Most welcome FDA’s decision
TIMELINE: FDA reverses ruling after evidence, pressure mounted

More Headlines
Doyle signs bill limiting BPA use (20)
Assembly backs limits on BPA in baby bottles (26)
Regulator waffles on bisphenol A (24)
EPA official says agency will act soon on BPA
It’s best to avoid BPA, federal official says

Featured Investigations

BPA industry fights back with public relations blitz
The chemical industry is under attack over bisphenol A, a key ingredient in hard, clear plastic products. Now, the industry is pushing back with an unprecedented public relations blitz.

FDA relied heavily on BPA lobby
As federal regulators hold fast to their claim that a chemical in baby bottles is safe, e-mails obtained by the Journal Sentinel show that they relied on chemical industry lobbyists to examine bisphenol A’s risks, track legislation to ban it and even monitor press coverage.

Use of plastic bottles increases BPA in study

EPA veils hazardous substances
The U.S. Environmental Protection Agency routinely allows companies to keep new information about their chemicals secret, including compounds that have been shown to cause cancer and respiratory problems, the Journal Sentinel has found.

BPA leaches from ‘microwave safe’ products
Products marketed for infants or billed as “microwave safe” release toxic doses of the chemical bisphenol A when heated, an analysis by the Journal Sentinel has found.

Plastics industry behind FDA research, study finds
A government report claiming that bisphenol A is safe was written largely by the plastics industry and others with a financial stake in the controversial chemical, the Journal Sentinel found.

Donation raises questions for head of FDA’s bisphenol A panel
A retired medical supply manufacturer who considers bisphenol A to be “perfectly safe” gave $5 million to the research center of Martin Philbert, chairman of the Food and Drug Administration panel about to make a pivotal ruling on the chemical’s safety.

EPA fails to collect chemical safety data
A few blocks from St. Josaphat Basilica on Milwaukee’s near south side, a company called Milport Enterprises makes more than a million pounds a year of a chemical that no one knows much about, not even the company executives. This is despite a decade of promises by the federal government to provide safety information about just such chemicals.

Hazardous flame retardant found in household objects
A flame retardant that was taken out of children’s pajamas more than 30 years ago after it was found to cause cancer is being used with increasing regularity in furniture, paint – even baby carriers and bassinets – and manufacturers are under no obligation to let the public know about it.

EPA drops ball on danger of chemicals to children
The Environmental Protection Agency is supposed to evaluate compounds in products such as flame retardants in mattresses and car seats to see if they are especially harmful to children. But it doesn’t.

Warning: Bisphenol A is in you
The federal government’s assurances that a common chemical is safe are based on outdated U.S. government studies and research heavily funded by the chemical industry.

GUIDE: What you can do to minimize your chemical exposure

Are your products safe? You can’t tell.
Congress ordered the federal government in 1996 to begin testing and regulating certain chemicals suspected of causing cancer and a host of developmental problems. Eleven years later, not a single compound has been put to that test.

AUDIO SLIDESHOW: A chemical home audit
GRAPHIC: Room by room chemicals abound (pdf)

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