Johns Hopkins Magazine -- April 2000
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APRIL 2000


Ellen Silbergeld is not afraid to confront the chemical industry. She has the science to back her up.
APRIL 2000
Pioneers of Advocacy

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Lead's Nemesis
By Melissa Hendricks

Ellen Silbergeld got what she calls her "baptism" in environmental advocacy in 1975 at a scientific meeting. A newly minted PhD from Hopkins (Environmental Engineering, '72), Silbergeld described to her colleagues her research showing that lab mice exposed to lead in their drinking water became unusually active; the anti-hyperactivity drug Ritalin made them much calmer. During the Q & A session that followed, a normally collegial exchange, the questions took on a hostile tone. "Are you sure you did the experiments correctly?" "How do you know your results are valid?"

Afterward, a sympathetic colleague took Silbergeld aside and informed her that many members of the audience were representatives of a trade group for the lead industry or received funding from that organization. "There's a huge fight over whether to take lead out of gasoline," he explained, "and you're in the middle of it. You have to decide which side you're on."

Silbergeld decided to take a stand against adding lead to gasoline. Since then, she has achieved national prominence as an advocate for environmental health--an advocate who backs her views with solid science.

Today, Silbergeld directs the Program in Human Health and the Environment at the University of Maryland School of Medicine. Sipping coffee in her paper-strewn office one day recently, Silbergeld presents a relaxed appearance and takes little prodding to discuss her recent research. But her friendly manner belies a staunch determination, according to colleagues. "She's very pleasant and very demanding," says Julian Chisolm, a retired professor of pediatrics who ran Hopkins's lead poisoning program and was one of Silbergeld's mentors. "You're not going to divert her."

As a postdoctoral fellow at Hopkins, Silbergeld had become disturbed and intrigued by the many unanswered scientific and medical questions about lead. For example, workers who handled lead sometimes developed a drooping of the hand known as "painter's wrist." No one knew whether the basis was muscular or neurological. After studying the problem using nerve and muscle tissues and animals, Silbergeld discovered it was indeed neurological. (And her research linking lead exposure to hyperactivity, conducted during this period, ultimately was borne out: Lead is now routinely listed in pediatrics textbooks as one of the risk factors for the condition. Extensive research has also shown that lead exposure causes cognitive decline in children.)

In 1983, Silbergeld left the lab to sign on as senior toxicologist for the New York–based Environmental Defense Fund. There, she continued to tackle the lead paint issue. Though manufacturers had been prohibited from adding lead to interior paint since 1977, many children continued to be exposed, mainly through peeling paint in older homes. In the late '80s, a government report revealed that 3 to 4 million children were being poisoned by lead each year.

Unfortunately, the report got very little attention, says Karen Florini, a senior attorney at the EDF. "Ellen realized that part of the problem was that the report hadn't said where the kids were." So Silbergeld decided the data should be broken down to show how many children in each city had lead poisoning. That got people's attention, says Florini. EDF's city-by-city report of lead poisoning spawned hundreds of press stories. "Ellen's insight was in making the connection between science and public outreach and policy development, to bring the problem home and make it specific," says Florini. "The report played a major role in putting the issue of lead poisoning on the federal agenda in a major way."

At EDF, Silbergeld also argued for a ban on lead additives in gasoline, and worked on several other projects. In 1990, she decided to return to the lab. At the University of Maryland at Baltimore, she is studying, among other things, the effects of lead on menopausal women. She finds that lead stored in bone is released during menopause. Blood lead levels rise 30 percent during menopause, says Silbergeld, an increase associated with a rise in blood pressure, diminished cognitive skills, and declining kidney function.

Silbergeld is still continuing her advocacy role as a consultant for EDF. In work with EDF begun a few years ago, she pointed out that the debate over chemical safety focuses on only about 200 of the approximately 80,000 chemicals registered with the U.S. Environmental Protection Agency. What about the other 79,800? she queried.

So with EDF colleagues, Silbergeld investigated the extent of toxicologists' knowledge--or lack thereof. The investigators concluded that 71 percent of the roughly 3,000 chemicals produced in large volume lacked basic safety information, such as data about effects on human reproduction.

The EPA responded with its own study and found that the figure was actually closer to 90 percent. Various chemical industries and organizations, based on their own data, agreed. The industries are now directing a five-year study to screen thousands of the high-volume chemicals.

Says Silbergeld, "We've finally turned the flashlight on the black hole of toxicology."