Environmental Endocrine Disruptors
Endocrine disrupting chemicals (EDCs) consist of synthetic and naturally occurring chemicals that affect the balance of normal hormonal functions in animals. Depending on their activity they may be characterized as estrogen modulators or androgen modulators. They may mimic the sex hormones estrogen or androgen (thereby producing similar responses to them) or they may block the activities of estrogen or androgen (i.e., be anti-estrogens or anti-androgens). One of the first recognized synthetic EDCs was diethylstilbestrol (DES), a pharmaceutical product given to pregnant women from 1948 to 1972 to help prevent miscarriages. It caused clear-cell carcinoma in the vagina, reproductive abnormalities in young adult female offspring, and a much higher than normal rate of genital defects in male babies. A second source of EDCs, collectively called “phyto-estrogens,” includes foods such as soybeans, apples, cherries, wheat, and peas. And yet a third group of endocrine modifying chemicals are some environmental pollutants. These environmental endocrine disruptors (EEDs) were the subject of a special Issues Workshop at the 13th Annual EPA-ACS Waste Testing & Quality Assurance Symposium organized by Dr. Keith in Washington, DC July 8, 1997.
EEDs may cause a variety of endocrine and reproductive system defects including malformations of newborns, undecended testicles, abnormal sperm, low sperm counts, feminization of males and masculinization of females, thyroid dysfunction, etc. In addition they are also suspected of contributing to increased evidence of cervical, breast, and prostate cancer. A major concern is that EEDs may exhibit their primary effects on the developing fetus; in these instances the time of exposure is more critical than the concentration level, but in all cases the environmental levels of concern are extremely low (e.g., parts per trillion and below).
The challenges to environmental analytical chemists include developing methods to screen and monitor for EEDs at very low levels and to determine which of the hundreds or thousands of pollutants in the environment are EEDs. The challenge is very real. In August 1996 President Clinton signed two bills (the Safe Drinking Water Act and the Food Protection Act) which mandate, within just a few years, the monitoring of these chemicals. Thus, intensive efforts are being mounted by EPA, the CDC, and other government agencies to develop strategies and methods to cope with this newly defined group of chemicals. Much of the government’s efforts are still focused on the effects of EEDs but the focus of these web pages is on their analysis. This will become especially important in just a few years when these chemicals have to be regulated in food and the environment because you can’t regulate a pollutant until you can reliably analyze for it. And you can’t analyze for it until you identify it.
The following data provides comprehensive information on what pollutants are known or suspected EEDs, what their chemical and physical properties are, why they are on various lists, and the best ways of analyzing for them using today’s methods.
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