Theo Colborn

A controversial scientist speaks on plastics, IQ, and the womb

Image: Tom Wolff

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For her groundbreaking work on the effect everyday chemicals have on children, Theodora “Theo” Colborn has been called “the Rachel Carson of the ’90s.” Just as Carson was pilloried for her 1962 book Silent Spring, which warned of the dangers of the pesticide DDT, Colborn has been in the hot seat for her 1996 book Our Stolen Future (co-authored with Dianne Dumanoski and John Peterson Myers). Colborn’s controversial message is that even low-dose exposures to many of the man-made chemicals found in common plastics, cleaning compounds, and cosmetics can affect newborn babies and developing fetuses, and can cause a range of problems, including low IQs, genital malformations, low sperm counts, and infertility.

Though scientists have voiced concerns for more than 25 years about the chemicals that disrupt the endocrine (or hormone-secreting) glands, researchers like Colborn are using a multidisciplinary approach—merging toxicology, endocrinology, embryology, and psychology—which has resulted in recent breakthroughs. Some critics have dismissed Colborn’s work as fear-mongering pseudoscience. However, in a December 1997 report published by the National Institutes of Health, a researcher set out to review the studies cited in Our Stolen Future on lowered sperm counts and was surprised to find that sperm counts in Europe and the U.S. are even lower than Colborn had initially reported.

Now 70, Colborn raised four children and worked as both a pharmacist and a sheep rancher before her environmental concerns inspired her to go back to school. She received her doctorate in zoology at age 58 and is now a senior scientist at the World Wildlife Fund, where she directs its Wildlife and Contaminants Program.

Q: A recent NIH report showed that a number of organic pollutants and industrial chemicals act like hormones, such as estrogens that can either bring out feminine characteristics or work to counteract male hormones.

A: That’s right.

Q: What are the implications of this?

A: What I have always said is that we are neutering the population—we are making females more masculine and we are making males more feminine. Up until day 56 from the day of conception you can’t tell the sex of the fetus. The tissue that’s there is going to eventually produce testicles or ovaries. Now, it takes just a slight tweak of a hormone to make it grow into a male tissue and become a testicle; a tweak in the other direction and it will become female tissue. What we’re finding in fish and birds and even mammals now are ovotestes, or testes that have ovarian tissue in them.

We’ve uncovered a new series of subtle effects, which probably take place during embryonic and fetal development and which have long-term effects that keep an individual from reaching his or her full development.

Q: What kind of effects?

A: We’re seeing an increase in hypospadias in boys. Hypospadias is a condition where the urethra doesn’t come out the end of the penis. This particular developmental process starts on day 56 in the womb and ends on day 84.

Q: And it has nothing to do with genetic predisposition?

A: Absolutely not. But what can cause this condition is dioxin and DDT. And it’s not just this type of hypospadias that is increasing but also the more severe form, where the end of the urethra actually comes out of the scrotum. It is almost impossible to repair surgically. Hypospadias and undescended testicles—another condition that results from males not fully developing in the womb—put young men at greater risk of developing testicular cancer, which is one of the fastest-growing cancers in the world, and is occurring in younger and younger men. Finally, males with hypospadias and undescended testicles always produce less sperm, which means they are more likely to have reproductive problems.

All of this should be taken into consideration when discussing pregnancy, but we often forget about the embryo. Even the federal government’s new Children’s Health Initiative talks about the child from the day it’s born through to puberty. They don’t talk about prenatal exposure. For some reason, there is this fear that if we talk about the embryo, people will mix it up with the abortion issue.

Q: You’ve determined that early exposure to toxins such as lead, PCBs, and dioxins is much more harmful than exposure later in life. Why?

A: During embryonic and fetal development, the brain isn’t developed yet, so you’ve got an individual that has no feedback mechanism to protect itself. The fetus is still growing new tissue, constructing its nervous system, constructing elements of its immune system and the reproductive tract. When all your organs are formed and fully functioning, it takes a lot more to blow them away.

Q: The transfer of these endocrine-disrupting chemicals occurs not only during pregnancy but also during breast-feeding. According to Environmental Protection Agency estimates, an infant who is breast-fed for one year will receive between 4 and 12 percent of its total lifetime exposure to dioxins. Is breast-feeding doing more harm than good at this point?

A: We don’t have enough evidence yet. But I’ll tell you quite frankly that I would not want to have to make the decision myself today. It appears that breast-feeding strengthens a baby’s immune system, but we also wonder how these chemicals might be interfering with immune competency in these children. So far, the benefits seem to outweigh the risks, but we just don’t know.

Q: Is there a way to prove a causal relationship between endocrine-disrupting chemicals and developmental problems, such as attention deficit hyperactivity disorder (ADHD) in children?

A: We’re never going to be able to prove a causal relationship of anything in a human being because we can’t feed chemicals to human beings and wait for them to grow up. With ADHD it’s very difficult because the syndrome is probably precipitated prenatally or in early infancy through something that interfered with the development of the brain. And the presence of that chemical in that individual later on in life may or may not indicate that it was the cause. Despite the fact that there are a lot of misdiagnosed kids, I still think ADHD is on the increase. And the evidence is almost overwhelming that these chemicals are involved.

Q: Yet in response to the data in your book, one conservative journal stated flatly that there was absolutely no conclusive evidence linking developmental problems and environmental chemicals.

A: That’s not true. I’ll just mention one new report by the U.S. Agency for Toxic Substances and Disease Registry that says a sizable proportion of our child population is being exposed to PCBs and their co-contaminants and that these chemicals are affecting our children’s neurological and neuromuscular development.

Q: According to United Nations statistics, from 1950 to 1955 the global fertility rate was 5 children per woman; today it’s estimated at 2.8. Many hail this decline and cite education, family planning, urbanization, and later marriage as the cause. Not much attention is paid to possible environmental factors.

A: Isn’t that amazing? We first began to see a decline in 1970. That is about the time that the first set of individuals exposed in the womb were reaching reproductive age. I’ve said there’s a connection all along, but no one wants to take chemicals into consideration.

Q: But surely we have to acknowledge social factors.

A: Of course. But environmental factors have been a lot more important than people realize. Even Paul Ehrlich [a Stanford University population biologist], who has focused on demographic shifts caused by women getting an education, which impacts fertility rates, is backing down. He has admitted now that we also have to include toxic chemicals in that demographic shift.

Q: How have corporations responded to your research?

A: Let’s put it this way: Last night on television I saw a new advertisement on the wonders of plastic and how safe it makes the world for children. I know this is in direct response to our work. This is how they are spending their money: to create the image of motherhood and apple pie where they know they are going to be blasted as the science comes forward.

Q: Are any working with you?

A: The major chemical manufacturers—the petroleum processors, the plastics producers, and the pesticide manufacturers—are not. But the people they supply are. The people who actually produce and package the products that come into your home are very concerned, because they know in the end they are going to be held liable.

Q: But if endocrine-disrupting chemicals and their byproducts are so widely used in paper, solvents, and plastics, how do we avoid them?

A: We may have to do triage. We may need to decide that there are certain places where we are going to use some of these chemicals, like in airplanes, in bridges, or in construction materials that we’re not directly exposed to in buildings. The fact is, some plastics are far more durable than steel. But we’ve got to get rid of the endocrine-disrupting chemicals used in children’s toys, cosmetics, and cleaning compounds.

Q: Is the government doing more than just calling for more studies?

A: The EPA is moving very rapidly. But it can’t do anything until we come up with recommendations for screening and testing methods.

However, every industry has already started testing its products. They’re not waiting. I am convinced, and I have said it publicly, that industry is going to make a tremendous amount of change before the government ever even gets around to writing the first regulation. They are modifying products already.

Q: Which products?

A: Well, for example, you used to see “microwavable plastic wrap” in the supermarket. Now, most manufacturers just put “plastic wrap” on the box and give clear instructions for microwave use. [Studies have shown that chemicals leach out of some plastics when heated.]

Q: To a layperson, your warnings about the dangers of endocrine disrupters are compelling. But when the research is so heatedly contested, one can’t help but question whether this isn’t just another “technology is bad” campaign.

A: People should look to the scientific journals, but they should also look very carefully at where the scientists who research and write about this issue get their funding.

The issue is very confusing, in part, because there are a lot of industries involved—petroleum, chemical, pesticide, pharmaceutical. But then look at the scientists who are trying to demonstrate that endocrine disruption is real. Where do they get their money? Follow the money. That’s what the public is going to have to do.

Q: But that means independent scientists are going to have to lead the way, even though they don’t have funding resources.

A: The responsibility lies with the industries that have made the money on these products. They could easily afford to put up a collective $100 million per year to support the kind of research agenda we need. Industry has a moral responsibility to put that money into the pot. And, let’s face it: They want a healthy population to which they can sell their products.

Q: Can we be realistic for a moment? Do you actually think industry is going to be willing to act in the public interest when there are so few examples of this ever happening?

A: That’s exactly why I’m making this point. I am praying that we can find one or two really conscionable corporate executives who are willing to dedicate the rest of their lives to future generations. This is our only hope. This is why I’m doing this work. I pray I live long enough so that I can needle enough people to do it.


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