Volume 5, Number 2
May 1992

Chlorinated Organics are Even Worse Than We Thought--For Animals, Anyhow

Dioxin is one of a dozen chlorinated organic compounds that have been found to behave like hormones in animals, especially fetuses and newborns, both in lab studies and in the wild. Even a very small exposure in utero profoundly affects the sexual physiology of the developing fetus and its subsequent adult behavior. Lab rodents exposed to PCBs and dioxins were born as feminized males or masculinized females. Fertility in affected animals goes down and birth defects go up. Suppression of the immune system has been observed in seagulls that eat contaminated fish.

So far there has been no study with humans, unless you count the studies done on the synthetic estrogen DES (diethyl stylbestrol), which caused infertility, cancer and defective reproductive tracts in the daughters of women who took it while pregnant. DES is not a chlorinated organic, but like the chlorinated organics, it mimics some of the behavior of hormones and throws the body's natural method of regulation off kilter.

Scientific interest in these effects only began 10 or 12 years ago, among scientists investigating different animals. They did not compare notes until last summer, at a small conference in Racine, Wisconsin. Since then, their work has been more focussed and better coordinated, and we can expect more news in the next few years.

The hormonal effect of chlorinated organics may turn out to be as great a concern as cancer, or greater. Even though these compounds are regulated in this country, they enter our environment through weather systems and in the tissues of migratory birds, from countries where they are still used. (From the New York Times, March 24,1992, p. B5)