Document from the U.S. Department of Health and Human Services

John R. Bucher, Ph.D

       In 2008, John R. Bucher, Associate Director of the National Toxicology Program of the U.S. Department of Health and Human Services, presented information to the United States House of Representatives' Subcommittee on Commerce, Trade, and Consumer Protection Committee on Energy and Commerce concerning issues about BPA and phthalates.  His statement was published in a document titled National Toxicology Program Determinations on the Health Effects of Bisphenol A and Phthalates.  His statement confirms several concerns about BPA and Phthalates.

BPA Exposure Underestimated

"There are a range of molecules that are natural, and some are incredible toxins. But when we start to make molecules that are not known to nature, we need to think a little more carefully about how they are going to interact with biological systems." - Zoeller (University of Massachusetts, Amherst)

This quote was obtained from an article in The New York Times titled, Study: Human Exposure to BPA 'Grossly Undersestimated'. The article was posted on September 20, 2010 and can be viewed at this link. Additional information from the article is discussed below:


Exposure Limits:

• Bisphenol A(BPA) can be found in 90% of the American population
• According to the U.S. Environmental Protection Agency(EPA), the human exposure limit for BPA is 50 micrograms per kilogram of body weight.
• It has been found that the average person is exposed to 400 micrograms per kilogram of body weight.

Since most people do not think in terms of micrograms and kilograms, let's do some math.

50 micrograms = 0.00005 grams = 1.10x10^-7 pounds BPA
1 kilogram = 1000 grams = 2.20 pounds of body weight
1.10x10^-7 pounds BPA /2.20 pounds of body weight = 5.00x10^-8 pounds BPA per pound of body weight
A person weighing 150 pounds should only take in 7.50x10^-6 pounds of BPA or 0.003 grams of BPA.



BPA Mimics Estrogen

• BPA is an "endocrine disrupter" because it mimics estrogen in the body.
• The estrogen receptor, male hormone receptor, and thyroid receptor can be bound by BPA.
• BPA's first use was as a "man-made estrogen substitute". This is why it resembles estrogen.

Two Studies of BPA

In 2002, a German scientist from the University of Wurzburg named Wolfgang Volkel conducted the only BPA study performed on humans. According to his study, 99% of BPA in the blood is removed by the liver. He also concluded that it is excreted from the human body in six hours. However, many researchers "say the the method Volkel used to measure BPA in the blood was not sensitive enough and that he likely overestimated the ability of the chemical to pass through without causing harm."

A recent study by a biologist from the University of Missouri named Julia Taylor was performed on mice and monkeys. The method she used is more sensitive for measuring BPA levels. Blood samples revealed that "biologically active" amounts of BPA were found in the mice and monkeys. She concluded that BPA circulates in the blood because the liver is not able to completely remove it. Furthermore, the BPA levels in blood "are cause for concern".

BPA and Politics

Senator Dianne Feinstein aims to amend the "FDA Food Safety Modernization Act". The amendment would ban BPA from the packaging used in children's food and drinks.

Dianne Feinstein

Analysis of the Article

While the article is not from a scientific journal, it uses evidence from scientific articles and studies. So, it uses strong evidence. The article is also unbiased because it discusses the subject from multiple viewpoints and considers several sources. The article gains credibility from being published in The New York Times, a widely accepted newspaper. However, the evidence was interpreted by a newspaper journalist instead of someone who has first hand knowledge of the subject. Some information obtained from the evidence is likely to be left out of the article in order to fulfill the journalist's arguments. Overall, the evidence provided in the article is reliable.

Bisphenol A and Ethics

The controversy over Bisphenol A has led to many studies. These studies have been performed by industrial companies and government agencies. In some studies, the results seem inconclusive. They do not always reveal what actions should be taken next. The interpretation of the results for a study depends on the scientist who performs it; therefore, there will be studies concluding that Bisphenol A is harmful while others conclude that it is not. It is also no surprise that most studies funded by industrial companies will be interpreted with a bias towards Bisphenol A being safe.

Anything in excess can act as a poison in the human body. Even water, the very thing that all life depends on, can be harmful if consumed in excess. The focus on BPA should not be arguing about whether it is harmful or not, because in high levels it no doubt will be. Instead, the focus should be on finding the proper limits of exposure. In addition, all possible actions should be taken to limit exposure. Toxicology studies have been performed on mice, rats, rabbits, and guinea pigs. While these toxicology studies might tell us the exposure limits for small animals, they do not directly tell us the appropriate limits of exposure for humans. It would be unethical to test exposure limits on humans. So, we have a dilemma. In the case of a dilemma, one looks at both the positive and negative consequences. From these considerations, it is the obligation of those in charge to take an ethical action.


What ethical actions should take place?

• When in doubt, it is better to err on the safe side. In 2008, Canada banned Bisphenol A from being used in baby bottles. An article in the Washington Post discussing this can be viewed here. The article discusses why Canada decided to act as they did. The article also discusses the steps the United States and individual companies have taken as a result.
• The public should be informed of the products they are buying. Products that contain BPA should have a warning label. Just as consumers have the right to know the nutritional information of products, consumers have the right to know what chemicals were used to make it. Consumers should also be aware of which plastics are designed for one time use or multiple use.

Additional Research

While researching, I found the National Toxicology Program which is part of the Department of Health and Human Services. The National Toxicology Program aides the Food and Drug Administration in setting exposure limits. On their website they post toxicology reports and emails that they receive from the public. I came across one email that makes several excellent points.
The website for the National Toxicology Program can be viewed here.
Click here to view the email.

First Academic Post: Bisphenol A

Recently, I found an article in a scientific journal called Reproductive Toxicology. The article is titled Human Exposure to Bisphenol A (BPA)  by Lauren Vandenberg Et al. It discusses several studies dealing with BPA that the authors have come across. By looking at the results of all of the compiled studies, the authors have determined which findings are most evidently accurate. The basics of BPA and the conclusions formed will be summarized from the article.

Basics of BPA

Production and Use of BPA
According to the article, over six billion pounds of BPA are produced worldwide every year. BPA is used in many products including "polycarbonate plastics, epoxy resins used to line metal cans, and in many plastic consumer products including toys, water pipes, drinking containers, eyeglass lenses, sports safety equipment, dental monomers, medical equipment and tubing, and consumer electronics"(Vandenberg).

Detection of BPA
BPA has been detected in humans through testing the following:

• Urine
• Amniotic fluid
• Follicular fluid
• Placental tissue
• Umbilical cord blood

Conclusions of BPA Studies

 BPA Levels in Human Tissues and Fluid
The article concluded that 90% of humans even children and pregnant women have detectable levels of BPA in their body. Studies show that levels of BPA in humans are between 0.3-4.4 ng/ml. Samples taken from umbilical cords reveal that a developing fetus is subjected to approximately 1-3ng/ml of BPA. The article suggests that studies should be done to detect BPA levels in fat and organ tissue so that they can be compared to BPA levels in serum. This would provide further information on the bioaccumulation of BPA. Since studies of BPA levels in humans have only been done on people living in developed countries, the authors feel that these studies should also been done in less developed countries.

BPA Found in Environmental Sources
Studies conclude that BPA is released into the air, dust, and water from landfills. This is caused by the disposing of products containing BPA into landfills. The article explains that there is "extensive evidence that many of these products leach BPA under normal conditions of use"(Vandenberg).

The Metabolism of BPA in Humans and Animals
It has been concluded that BPA rapidly metabolises in humans and animals. Soon after exposure to BPA, (most likely from the presence of BPA in food) BPA can be directly detected in blood and urine samples. However, evidence suggests that animals and humans do not metabolise BPA the same way. More testing should be done that specifically focuses on the metabolism of BPA.


Why I Considered this Article as a Source
This article is a reliable source because it objectively compares the results of multiple studies instead of relying on just one study. It was published in a scientific journal where it has been peer reviewed and cited in 118 scientific articles since 2007. The authors are from the Tufts University of Medicine and the University of Missouri-Columbia; therefore, their research was not biased by a political, industrial, or commercial agenda.

Sources:

Laura, Vandenberg N., Hauser Russ, Marcus Michele, Olea Nicolas, and Welshons V. Wade. "Human Exposure to Bisphenol A (BPA)." Reproductive Toxicology 24 (2007): 139-77. Web of Science. Web. 31 Jan. 2011.

To view the abstract for this article click here.