Hormone disruptors are not some fancy new weapon developed by the Klingons to destroy all the Star Trek-loving humans on planet earth. Rather, they are chemicals that we use everyday. It's a relatively new discovery that hormone disruptors—also known as endocrine disrupting chemicals (EDCs)—can mimic estrogen or other important chemicals that help run the bodies of humans and other animals. Hormone imbalance can lead to serious health problems.
Today we get an overview of how the problem of hormone disruptors arose and where the issue stands. Our article on these endocrine disrupting chemicals comes from Joseph K. Sheldon, Professor of Biology and Environmental Science at Messiah College in Pennsylvania, and David K. Foster, Associate Professor of Biology and Environmental Science, also at Messiah College. It has been excerpted from an article they previously published in Christian Scholars' Review.
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Global Toxification—Hormone Disruptors
The initiation of "Clean Laws" in the 1970s and their subsequent renewals dramatically decreased pollution in the United States. The air is cleaner—people no longer die of a single
smog event, as they did in Donora, Pennsylvania in October of 1948, and rivers don't catch on fire, as the Cuyahoga River of Cleveland, Ohio did in 1936, 1952, and most famously in 1969. Even sewage treatment has advanced so that every American city has at least secondary treatment, and many plants can remove most of the excess phosphorous and nitrogen before the water is returned to nature's ecosystems.
Chemicals that were directly toxic to humans, such as arsenic and nicotine pesticides, and even some chemicals that are known carcinogens, are now largely removed from our food supply.
Still, we are left with troubling, environmentally related health problems. The most directly visible of these is cancer, with rising rates throughout the industrialized world. Some scientists estimate that environmental factors may be responsible for 25% of today's cancers. For example, during August 2002, the United States Environmental Protection Agency released a report acknowledging the link between inhaling diesel exhaust and cancer. Formaldehyde also has been tied to cancer recently and has been removed from most commercial applications. It was commonly used for embalming, but also was released from polyurethane foam and plywood, both of which are used in many household products.
Other chemicals such as DDT and PCBs were removed from use in the United States when we realized their danger to animals and humans. In none of these compounds, however, did we test for carcinogenic activity or further physiologic activity—such as the newfound ability of such compounds to mimic estrogen in animals and humans—nor did we test for cumulative exposure effects over one's lifetime. The chemicals were released for use following testing for direct toxicity only.
EMERGING AWARENESS OF ENDOCRINE DISRUPTORS
Theo Colborn has been a pioneer in the exploration of endocrine-disrupting effects of chemicals on wildlife and humans. Such effects should not be surprising to us—consider the tiny pills used to control a woman's ovulation cycle. Colborn's research has included a review of the scientific literature from the 1950's through the 1980's, where she found a wide number of abnormalities that seemed to be connected to endocrine system dysfunction.
Summarizing the extensive worldwide scientific literature on the topic of endocrine disruptors, the World Wildlife Foundation reports the following:
The effects of endocrine disruptors on animals are varied—ranging from alligators born with abnormally small penises and birds with crossed beaks, to the sudden disappearance of entire populations. Wildlife researchers over the last few years have unearthed a variety of endocrine disruptor-related effects:
- interrupted sexual development;
- thyroid system disorders;
- inability to breed;
- reduced immune response;
- abnormal mating and parenting behavior.
Species such as terns, gulls, harbor seals, bald eagles, beluga whales, lake trout, panthers, alligators, turtles, and others, have suffered more than one of these effects.
Though published works such as Colborn's book, Our Stolen Future, were originally seen as alarmist, continued laboratory study and epidemiological studies seem to bear out the initial conclusions of Colborn's work.
ENDOCRINE DISRUPTORS — A GLOBAL PROBLEM
There are hormone-mimicking compounds, including estrogen mimics, circulating in our global ecosystem. Acquired principally via the food chain, these compounds accumulate in animal body fat, including that of humans, and can cause reduction in immune function, mental impairment, and lifelong alteration of secondary sexual characteristics and behaviors. Moreover, these compounds are potentially linked to decreases in fertility as well as increases in some types of cancers throughout the industrialized world.
Unfortunately, very small amounts of endocrine disrupting chemicals—parts per million or parts per billion—can cause
profound effects during early developmental stages in mammals. Because these compounds accumulate in body fat, exposure risk is most acute during pregnancy and nursing.
As scary as these effects may be, the incorporation of endocrine-disrupting compounds into the global ecosystem was largely the result of purposeful use by people who believed that they were safe, based on assessments that they had low-level toxicity to adult organisms. Thus, there is no easy financial solution for removing the compounds. Unlike the tobacco companies, who have been sued for falsely advertising a product they knew to be both addictive and harmful, nobody knew the full impact of producing and using these chemicals in the burgeoning world of consumer products and services.
The longevity and current widespread presence of these compounds in the global ecosystem, as well as in our commerce systems, offer us a powerful lesson: Production and use of chemicals unknown in nature is caveat emptor—buyer beware. In the case of hormone-disrupting compounds, we have not been careful enough. Untested and unregulated chemicals are not necessarily safe. To do nothing about such compounds once we recognize a problem opens us to the same culpability and liability to the future generations that tobacco companies face now.
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Joseph K. Sheldon is Professor of Biology and Environmental Science at Messiah College in Pennsylvania, and is co-author of the book Redeeming Creation: The Biblical Basis for Environmental Stewardship. David K. Foster is Associate Professor of Biology and Environmental Science at Messiah College.
The above material has been excerpted from the article "What Knowledge is Required for Responsible Stewardship of Creation?" which originally appeared in Christian Scholars' Review, Volume XXXII, Number 4 (Summer 2003).
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