Panel Considers Methods To Test Man-made Chemicals

Determining Effects On Human Health Is Goal

April 29, 1997|By Timothy B. Wheeler | Timothy B. Wheeler,SUN STAFF

Venturing into an emerging environmental frontier, a group of experts meets in Baltimore this week to figure out how to test thousands of man-made chemicals for whether they may cause low sperm counts and abnormal growth and behavior in people and wildlife.

The two-day meeting starting today at Cross Keys Inn is the third for the 40-member panel, which is advising the Environmental Protection Agency on how best to identify the substances that can disrupt human and animal endocrine systems. It met earlier in San Francisco and Houston.

"Once you have a chemical that's in widespread commerce and society, if it's doing something across the population, it's very difficult to detect," said Lynn Goldman, assistant EPA administrator for pesticides and toxic substances. She is chairwoman of the federal advisory panel.

The endocrine system controls growth and reproduction by releasing hormones from glands. Endocrine-disrupting substances can mimic or interfere with the chemical messages delivered to the body by hormones.

Wildlife studies have found birth defects, sexual abnormalities and reproductive failure in bird, mammal and reptile populations exposed to certain pesticides and chemicals. Laboratory research and human data suggest similar effects may occur in humans.

But controversy remains over whether "endocrine disrupters" threaten people or wildlife, given the very low levels of such chemicals generally found in the environment.

The committee will hold an open forum from 7 p.m. to 9 p.m. today at Cross Keys Inn, 5100 Falls Road, for anyone wishing to comment on the issue. People exposed to high levels of chemicals that act like estrogen, the female sex hormone, have had health problems. One example is the drug DES, which was prescribed to pregnant women in the 1960s. Their daughters were found to be more likely to develop an unusual form of cancer.

There also have been documented instances of chemicals disrupting reproduction and development of wildlife. Scientists blamed DDT for the drastic decline of bald eagles in the 1960s and 1970s, for instance, because traces of the pesticide in the birds' prey caused them to lay thin-shelled eggs.

DDT and some other endocrine-disrupting chemicals have been banned or restricted by EPA for their potential to cause cancer in humans, not because of their ability to act like hormones.

But in the past year, Goldman noted, EPA has moved to restrict vinclozolin, a fungicide used on some fruits and vegetables. The agency is acting on evidence that the chemical causes male laboratory mice to develop abnormally small penises and have low sperm counts, she said.

The testing advisory panel stems from new laws enacted last year to protect the food supply and drinking water.

Congress directed EPA to begin screening for contaminants that may disrupt human endocrine systems.

The advisory panel must recommend a testing plan to EPA by the end of this year, and the agency is to begin by 1999.

The panel's task, which has been broadened to screen substances for their potential impacts on wildlife, is paired with a $10 million research effort by EPA seeking more definitive information on the actual threats.

One of the issues confronting the experts is where to begin testing, with more than 70,000 chemicals in commerce today.

The panel will seek to set some priorities on which substances, or related groups, to check first.

"There just are not enough people, laboratories or hours in the day to go through each chemical," said Peter deFur, an associate professor at Virginia Commonwealth University in Richmond, and one of the panel members.

Pub Date: 4/29/97

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