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Feature Story
Bad Chemistry: A Special Report
Page 2

Photo of Theo ColbornSHE WENT LOOKING  One of the researchers most responsible for raising this question and pressing to find answers is Theo Colborn, a woman whose career path has been anything but conventional. Colborn got her Ph.D. at 58, an age at which most people are beginning to think about retirement. By then, she had raised four children while working as a pharmacist, a job that required her to know a great deal about chemistry, biology, and health. In the 1970s she began to see disturbing patterns of illness in the six Colorado communities where she worked as a pharmacist. Eventually, she hypothesized that everybody drank from the local creek or river and each water source had its own unique set of toxins. She went to a number of conferences on water in the Western states and was shocked to find that all anybody talked about was the quantity of water -- and who owned it.

Divorced, without a mortgage, her children grown and gone, Colborn decided to go back to school to make herself an expert on the quality of water. A master's degree in freshwater ecology led to a doctorate in zoology, then two years as a Congressional Fellow in the Office of Technology Assessment in Washington.

Then, in 1987, she landed at the Conservation Foundation, where her new boss asked her to take on a survey of research on the impact of pollution in the Great Lakes, a study that determined the course of her life's work. A younger scientist would probably have wanted to make her own mark rather than reading over other people's work. There is little glory in this kind of analysis, no tenure. One of Colborn's gifts was that she enjoyed looking for patterns. She was, and is, one of those rare people who can hold thousands of details in her head, shuffling and reshuffling them, able to tolerate the uncertainty of not knowing where they will take her. For six months, she worked seven days a week, reading more than 2,000 research papers and 500 government reports. She developed a primitive filing system: 43 boxes of documents, one for each species that had been studied.

At first, Colborn went looking for increases in cancer, but she found, instead, other problems that disturbed her. Where hundreds of bald eagles had nested on the Great Lakes' shorelines, only 45 pairs remained. Inland, these birds had rebounded in the years since DDT had been banned; near cleaner lakes they also flourished. But on the shores of the Great Lakes, deformed birds were showing up across species with missing eyes, crossed bills, clubfeet. A startling number of gull and tern nests sheltered twice the number of eggs they should, which suggested that females were sharing nests, apparently for lack of a male companion. Many males were not mating or not parenting. Some birds were abandoning their nests altogether. Chicks seemingly born healthy quickly developed a wasting disease and died. Creepy stuff, but what did it mean? She sought out wildlife biologists who told her that they, too, sensed something was wrong, but none of them could put a finger on what it was. Tissue analyses of the animals kept turning up the same chemicals, including DDT, dieldrin, chlordane, lindane, and PCBs. Everyone knew that hundreds of chemicals had been discharged into the lakes, many of them persistent but impossible to measure with methods available at the time.

To tame the data, Colborn made an electronic spreadsheet for species that were most profoundly affected to figure out where the patterns lay. Before long, she realized that something fundamental had to be happening to explain such a wide range of symptoms: reproductive failures, genital deformities, thyroid malfunctions, behavioral abnormalities, and immune suppression. Eventually she decided the most likely probability was endocrine damage.

Her knowledge of endocrinology was sketchy, so she set herself the task of mastering it. Endocrinology is the science of hormones, the chemical signals that, in myriad delicate and subtle ways, manage an organism's most vital functions. Hormones tell the ovaries and testes how to make eggs and sperm, tell the lungs how to breathe, the intestines how to digest, and the heart how to pump; they direct neurons in the brain. The way they do their work is an extraordinarily complicated dance that scientists are still working to comprehend. Estrogens, the female sex hormones, have been accorded the most attention so they are best understood; the male hormones, androgens, run second; and the thyroid, which controls brain development, is a distant third. If hormones cannot do their job properly, the consequences are legion -- some subtle, some disastrous. The wrong balance of estrogens and androgens, for instance, can lead to reproductive failure. If a fetus suffers even a small drop in thyroid hormone levels, learning disabilities may be the consequence, IQ points may be lost.

Colborn drew up a list of world-class scientists from different fields -- endocrinology, biology, immunology, toxicology, psychiatry, ecology, anthropology -- whose work gave them, collectively, the expertise to test her suspicions, and invited them to the Wingspread Conference Center in Racine, Wisconsin, in the summer of 1991. "I was scared to death! There I was, a brand-new Ph.D. who knew only a handful of wildlife biologists." She did her best to set up conditions in which this wary bunch could find common ground. "I kept them working from morning till night so they had to get to know each other," she says. "Thank God there were no cell phones back then." Right away, people began to see surprising connections between their work. They stayed up talking into the small hours.

The term endocrine disruption was coined at the meeting. As the fruit of their work, the group issued a consensus statement that has stood up well to the test of subsequent research. The participants agreed that many man-made chemicals had the potential to disrupt the endocrine system of animals, including humans, by mimicking the activity of a hormone, by blocking it, or through other mechanisms, and that many wildlife populations had already been affected. Even more disturbing, they emphasized that the fetus and newborn are at greatest risk, and that the effects might not be manifested until the animal was mature. Perhaps the greatest bombshell was the statement that "the concentrations of a number of synthetic sex hormone [disruptors] measured in the U.S. human population today are well within the range and dosages at which effects are seen in wildlife populations." Suddenly, this was not about cleaning up a few lakes; the health of all the creatures in our care was at stake -- including the health of our unborn children.

Forecast: Dry and Brutal
Mammoth Mystery

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Photo: Lynn Johnson

OnEarth. Winter 2006
Copyright 2005 by the Natural Resources Defense Council