NEW YORK, Oct 22 (Reuters Health) -- Baby teeth from children born in New York, New Jersey, and Florida in the 1980s have been found to contain a radioactive element at levels similar to those seen in the 1950s, when aboveground atomic bomb testing was taking place, according to findings presented at a Manhattan press conference on Thursday.
The findings are cause for concern, according to the Radiation and Public Health Project (RPHP), because the isotope, Strontium-90 (Sr-90), has been linked to leukemia and other forms of cancer.
"The levels of Strontium-90 should have dropped down to near zero once humankind stopped exploding nuclear weapons in the atmosphere," said study author Dr. Ernest Sternglass in a statement. "Instead the levels stayed essentially the same as during the bomb-test years, or in some areas they even increased."
As part of the "Tooth Fairy Project," launched last February, 1,500 families from New York and New Jersey donated their children's teeth to RPHP at the request of actor Alec Baldwin, who is on the board of directors of Standing for Truth About Radiation (STAR). Although the study is continuing, with a goal of analyzing at least 5,000 baby teeth, early results are "quite alarming," said Sternglass, because 515 of the teeth revealed high levels of Sr-90.
Strontium-90 is a byproduct of nuclear fission. From the mid 1950s to the early 1960s, researchers measured increasing amounts of Sr-90 in the bones of New York City cadavers, as well as in baby teeth collected in St. Louis. The alarm caused by these and other findings led President Kennedy to sign the 1963 Nuclear Test Ban Treaty, which banned aboveground testing of nuclear weapons. President Lyndon B. Johnson later remarked in his 1964 remarks on Preserving the Test Ban Treaty, "the dread Strontium-90 and Iodine-131 have disappeared from the environment."
But the new findings show Sr-90 levels comparable to those reported in the 1950s. Sr-90 "enters the body through drinking water and food, concentrating in bones and teeth," according to an RPHP statement.
"The fact that we're finding (Strontium-90) at much higher levels than we expected indicates that the dangers from radiation in our diet were not eliminated with the cessation of atmospheric bomb testing," said Dr. Jay M. Gould, an RPHP co-director.
"Strontium-90 is still persisting in the human environment," added Gould in a statement.
The researchers attribute some of the radioactive fallout to the 1979 Three Mile Island reactor accident in Pennsylvania, and the 1986 Chernobyl disaster in Russia. Airborne emissions from four nuclear reactors in Suffolk County, New York, in the early 1980s may also have contributed to the isotope levels found in the baby teeth donated by parents from that area.
The RPHP directors are calling for the federal government to study levels of Strontium-90 in the environment nationwide. They note that a US Department of Energy program that measured levels of the radioisotope in adult bone ended in 1982, and the Environmental Protection Agency stopped monthly reports of fission products in milk in 1990.
"Regardless of the precise source of the radiation, it is clear that more investigation is urgently needed," said Sternglass. "The situation is especially serious given that Strontium-90 is a known carcinogen and a marker for other shorter-lived fission products and simply should not be present at all in our children's teeth."
