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Environmental Estrogen - Global Problem

by Pat Cody
Berkeley, California

This article by DES Action president Pat Cody describes how the research done into the effects of DES (Note: It has been known since 1971 that DES (diethylstilbestrol), a synthetic hormone drug, causes cancer in women exposed in-utero) has served as a model for study of exposure to pollutants around the world that have estrogenic effects.

The leading center for research on DES effects on mice is the National Institute for Environmental Health Sciences (NIEHS), one of the nine institutes of the National Institutes of Health. We have learned much about effects on humans from the studies on mice, and the NIEHS scientists have learned from us. As they wrote in their journal for June 1993,

"... DES may be viewed as a model compound for other environmental agents with estrogenic potential. The bio-accumulation of these environmental estrogens is recognized as a problem of increasing magnitude. Certain human populations in the United States have been shown to carry amounts of these fat-soluble compounds which, in fish and other wildlife, cause significant endocrine dysfunction and developmental anomalies of the reproductive tract. Insights into the biological effects of DES should therefore provide a foundation upon which future environmental health problems may be effectively addressed."

We are five years down the road from that statement, and scientists world-wide have confirmed the problems of exposures to pollutants that have estrogenic effects:

  • Frogs and other amphibians are dying out or showing bizarre changes like extra legs or missing eyes. Scientist David Wake of the University of California at Berkeley said that the comparison often made between changes in amphibians and the canaries that once warned coal miners of danger isn't quite right. "If a canary died the miners got out of the mine. We don't have that option. We don't have any place to go."

  • Sperm whales who live in depths of 1,200 - 3,600 feet have dangerous chemicals similar to DDT and PCBs in their blubber.

  • Polar bears near the North Pole have been found with both female and male genitals. They are genetic females and some have had cubs, but they also have small penises in front of their vaginas. Scientists suspect PCBs in their fishy diet, since many pollutants evaporate in the south and fall to earth in cold northern air, where it is not warm enough for them to evaporate again.

  • Fish consumption advisories have been issued by Delaware, New Jersey and Pennsylvania because of high levels of PCBs in Delaware River fish. Sewage treatment plants and estuary sediments are believe to be the sources. The Minneapolis Star Tribune reported in April on male walleye fish from the Mississippi River with such high levels of estrogen and low levels of testosterone that their breeding ability may be impaired. Female walleye taken near sewage treatment plants had five times the normal level of estrogens in their blood, which could prevent ovulation. The Arizona Daily Star reported in June that 30 years after DDT was banned, parts of the Gila River near Phoenix still has levels among the highest in the U.S. Fish from the river have 24 parts per million of DDF, a break-down from DDT. U.S. and Arizona agencies set a hazard level for humans as more than 0.3 parts per million, so again, warnings have been posted about eating fish.

  • Florida Game and Fresh Water Fish Commission is studying a puzzling decline in alligator hatchings in Lake Griffin, according to an April story in the Christian Science Monitor. Alligator farmers told officials that only 4.4% of the 1,033 eggs they had collected were hatching, compared to the normal rate of 50%. They were told that practically none hatched in the lake last season and there have been "unexplained deaths" of turtles, snakes and fish. A similar decline in alligator hatchings, and the birth of abnormal alligators, occurred in Lake Apopka in the 1980s after a pesticide spill. This time, researchers think that pesticide and fertilizer use on farms near Lake Griffin may be responsible.

Turning to reports on humans, much of the news comes from Japan, where scientists and the general public are both becoming more aware of 'endocrine disruptors.' In June, the press carried a story that breast-fed babies in Japan were receiving about six times the daily tolerable amount of dioxins. They speculated that because dioxin is produced daily by the incinerators used to destroy mountains of garbage, it reaches the mothers in the environment. In May a press report from Tokyo stated that Japan had the lowest number of children in its population since organized census taking began in 1920. There has been a significant increase in infertile couples and a study from the World Health Organization showed that 33 out of 34 healthy Japanese men between the ages of 20 and 26 had below normal sperm counts. This July, a press report from Bombay stated that 70% of Indian men had fallen sperm counts because of pollution. Less than 30% had normal semen.

Our continuing insistence on keeping DES exposure a relevant concern, and the help of the media in doing stories on DES as one of the first 'endocrine disruptors,' has had results. The Baltimore Sun reported in June that the Clinton administration has listed endocrine disruption as one of its top five environmental research priorities. Congress ordered the EPA to start a chemical screening program by this August. The federal Dept. of Health and Human Services stated that many chemicals "have the potential to disrupt the normal functions of the endocrine system, (which) may have a serious impact on reproductive and developmental parameters in wild life and human populations."

Of particular interest to us is news of a World Breast Cancer Conference in Canada in mid July. Michele Landsberg, a columnist for the Toronto Star, wrote that the thrust of the conference was to demand action for prevention, rather than continue to concentrate all resources in a possibly vain search for a cure ... . "Pollutants are metabolized in our bodies as estrogen," said author and cancer surgeon Dr. Susan Love. And it is lifetime exposure to estrogen that has increased world cancer rates by 26% since 1980....We live in a toxic soup of chemicals.

For those interested in learning more about this problem, the book Our Stolen Future is an excellent resource, with suggestions at the back for actions you can take.

Pat Cody is founder and president of DES Action. DES Action's web site is at This article reprinted with permission from the DES Action Voice newsletter

Related article:
Published in In Motion Magazine August 1, 1998.