Glowing in the dark; baby teeth studies reveal childhood radiation exposure. (Your Health).

Some Washington University researchers were cleaning a musty old ammunition bunker at Missouri's Tyson Research Center last spring. There they stumbled across a bizarre find: 85,000 baby teeth. Stumped university administrators nearly discarded them.

Luckily, they didn't; the cached teeth turned out to be a scientific treasure trove. Over the next few years, they will give researchers the rare chance to measure how radiation levels in children's bodies affect their health in later life.

The teeth were unused specimens from the St. Louis Baby-Tooth Survey, a massive public health study mobilized by scientist and anti-nuclear activist Barry Commoner from 1958 to 1970. The United States had been conducting above-ground nuclear weapons tests, setting off about 100 bombs in the American West in the years following World War II. Radioactive fallout was increasingly detected in milk supplies and in the environment, and the public was growing uneasy about its effects.

Researchers working on the survey collected some 300,000 baby teeth from children in the St. Louis area. They found that the amount of strontium-90 (a carcinogenic radioactive agent) in those teeth rose dramatically during bomb-test periods, and fell dramatically after testing ceased. This helped spur the U.S. to sign the 1963 treaty banning atmospheric bomb tests.

Tracking the Babies

But what happened to those St. Louis children later in life? Did their exposure lead to high cancer rates or other illnesses? No one knows, but Joe Mangano and his colleagues at the New York-based Radiation and Public Health Project (RPHP) are trying to find out. The teeth have been shipped to RPHP's lab, the only place in the U.S. currently measuring the level of radiation in people's bodies. (The U.S. government hasn't funded such research in nearly 20 years.) These modern-day tooth fairies test fallen teeth from children born near nuclear power plants, and their aim is to find out how much strontium-90 resides in these children's bodies and what impact it has on them. Says Mangano, the St. Louis teeth have provided an opportunity to follow the medical histories of thousands of people with known levels of childhood radiation exposure.

For countless boomers who strolled around in the 1950s and `60s wearing "I Gave My Tooth to Science" pins, the news of the tooth discovery has revived old questions. Many of them began contacting Mangano. "So far, 2,150 people have called to fill out health questionnaires," says Mangano. RPHP's task is to match teeth with owners, analyze radiation levels and health histories, and begin to assess the impact the Cold War fallout had on public health.

"It's not an idle look into the past," says Mangano. "It's about the present and the future." And the reason why should pique the interest of every parent, because many of the teeth from today's children show strontium-90 levels as high as those found in St. Louis children at the height of the atmospheric bomb tests.

What Radiation?

But where is today's radiation coming from? Not from residual bomb fallout, say nuclear experts: strontium-90 from the bomb tests would have decayed to fairly low levels by now. According to RPHP studies, the radioactive agent appears to be highest in children born near nuclear power plants. Strontium-90 enters human bodies through cow's milk, water and produce grown in soil exposed to radioactive runoff or contaminated rain. Since it mimics the calcium needed to form teeth and bones, it easily permeates growing bodies. Once there, it can disturb bone marrow--where the white cells that fight cancer and germs are made. This, postulate researchers, puts exposed children at risk of leukemia, cancer and infectious diseases.

Over the past few years, Mangano and his fellow researchers have released their findings on some 2,000 teeth from children born near reactors in five states. In some regions, the researchers have shown that radiation levels and death rates from childhood cancers have grown at an almost identical pace. They have also found that when reactors close, area infant and senior citizen cancer mortality rates improve dramatically.

So far, teeth from children born in Miami-Dade County and other southeastern Florida counties have the highest concentrations of strontium-90 in the U.S., which might be explained by the fact that two nuclear reactors there emitted 10.39 trillion picocuries of radioactivity into the air between 1970 and 1987, an amount equal to about three-fourths of all the radioactivity released during the infamous Three Mile Island accident. In the same region, cancer rates for children under 10 rose 35.2 percent from the early 1980s to the early 1990s, compared to a 10.8 percent rise nationwide, according to one RPHP report.

Childhood cancer rates jumped 75 percent in the San Louis Obispo, California area after a reactor opened there. In Pennsylvania, the baby tooth researchers tracked a rise in childhood cancers that corresponded with a reactor opening. "We think it is strong evidence for a cause-and-effect relationship," says Mangano.

A Call to Action

As startling as they are, RPHP findings haven't yet translated into public policy. Little more than a year ago, most pundits were predicting a gradual phase-out of nuclear power in the U.S. But now the Bush Administration wants to license new nuclear power plants, and many of the 103 nuclear power plants soon up for relicensing may get a previously unexpected extended lease on life. Victor Sidel, past president of the American Public Health Association, says, "The [RPHP] studies are certainly cause for others to be done. If the findings are the same, then that's cause for social policy to be based upon them." The odds of other studies getting underway, though, do not appear high. The baby-tooth researchers have had to rely on private grants for funding and direct-mail appeals and volunteers to solicit teeth.

Connecticut nurse Agnes Reynolds is one of those volunteers. The mother of a nine-year-old boy battling leukemia, Reynolds doesn't know what caused her son's illness. But she does want to know why childhood cancer rates are soaring among children living near nuclear power plants, as her family does. So she asks parents to donate their children's teeth to the project. She wants people "to pay attention" to the risks around them. That's a lesson she says she may have learned the hard way. Unless the government taboo on studying radiation-caused health risks is broken, say researchers, countless others will, too. CONTACT: Radiation and Public Health Project, [phone], www.radiation.org. (The project generally doesn't provide individual results.)

New Hampshire-based writer JONI PRADED covers wildlife and environmental issues for a variety of magazines.