Fish and alligators are just two of the creatures under assault by endocrine disrupters in the environment.

Crossed wires? EPA tackles hormones disrupters Talk about a tough assignment. Per Congressional edict, the Environmental Protection Agency (EPA) has begun mapping out a vast program to check whether synthetic chemicals can disrupt hormones in humans and animals. These "hormone disrupters" can cause cancer, birth defects and immune problems. Even incredibly tiny concentrations can interfere with reproduction. The hormone disrupters are more evidence that chemicals can be dangerous even if they don't cause cancer. In humans, as in animals, hormones have many communications jobs, affecting mood and memory, reproduction and development, virtually any biological process you can name.

				U P D A T E D 21 OCT 1998 . An EPA advisory group has suggested an approach for screening some 87,000 chemicals for their potential to disrupt the endocrine system. To slash the cost and complexity of the chore, the group eliminated 25,000 large molecules as unlikely to cross biological membranes. The Endocrine Disrupter Screening and Testing Advisory Committee also recommended testing certain combinations of chemicals, such as breast milk contaminants, plant-derived estrogen mimics, and gasoline. In addition to their human health effects, the chemicals will probably be screened for hormonal effects on wildlife. (See "EPA Unveils..." in the bibliography).

While the nervous system sends electrical signals along nerves, hormones drift to their destination through the blood to cells that have the correct receptor molecules on their outsides.

Once locked onto a receptor, a hormone may instruct a cell to divide or make a certain protein. Or it may tell the cell to stop dividing or making proteins. A copycat crime? There's growing evidence that artificial chemicals in the environment can disrupt hormones by sending erroneous signals or blocking legitimate signals. Since the hormones are part of the endocrine system, the hormone disrupters are also called endocrine disrupters. And since the concern originated with estrogen, the "female" hormone, they are sometimes called estrogen mimics. That's enough jargon for now. Plenty, really. Where's the beef -- the proof that endocrine disrupters are damaging human or animal health? The strongest evidence comes from the animal kingdom. In the 80s and '90s, fish and beluga whales with horrible malformations showed up in the Great Lakes region, with cancers, ulcers and other deformations. In the 1990s, an epidemic of misshapen reproductive organs in Florida alligators was blamed on a pesticide spill into the lake they called home. Other reproductive abnormalities in gulls, mink, eagles and other animals have been blamed on chemicals that mimic hormones. Furthermore, in the laboratory, tiny concentrations of hormone mimics lock onto cell receptors, causing the cells to reproduce in a phenomenon that sounds suspiciously like cancer. Are hormone mimics giving us the fix?

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