The combination of remnants from Cold War nuclear testing and "CSI"-style technology may hold the key to identifying Gilgo Beach victims and resolving missing-persons cases around the country.
Scientists at the federal government's Lawrence Livermore National Laboratory in California, working with experts in Sweden and Canada, have been using carbon-14 dating to come up with more finely tuned approximate birth dates for human remains found in the wild. The science behind the technique also provides police with close approximations of dates of death.
In a method known as "bomb-pulse dating," scientists are able to place samples of human teeth, bones and hair in a device known as an accelerator mass spectrometer and measure the amount of carbon-14 they contain and determine a better approximation of when a person lived and died. Officials at the laboratory, in Livermore, Calif., are scheduled to announce developments related to two Canadian missing-persons cases Wednesday.
Bruce Buchholz, a scientist at the lab who is using the bomb-pulse technique, said the method could be useful in cases like the Gilgo investigation, where five sets of remains are still unidentified.
"It will be able to get dates of birth definitely from teeth and possibly dates of death, and that can narrow it down," said Buchholz, referring to the way knowledge of when a person was born can help police zero in on potential subjects and their relatives for further DNA testing. Hair strands can also be used, officials said.
Testing for carbon-14 costs several hundred dollars for each sample, said Anne Stark, a laboratory spokeswoman.
Dr. Yvonne I. Milewski, Suffolk's medical examiner, said her agency is "aware of carbon-14 dating techniques, their potential uses and limitations."
"We cannot comment on the ongoing Gilgo investigations," she said. "These techniques do not establish a specific identification. As a general policy, the medical examiner's office would consider pursuing any scientific method that could potentially provide additional information, and possibly assist in a criminal investigation."
The Suffolk medical examiner's office said it was aware of the method but wouldn't say if money would be spent on it.
"It sounds like it would be useful in cases where we have a body and don't know who it is," said Paul Browne, spokesman for the NYPD, which is not involved in the Gilgo case.
Carbon-14 exists naturally. But above-ground nuclear testing between 1955 and 1962 pumped larger quantities of the isotope into the atmosphere and into the human food chain. When testing ended in 1963, the amount of carbon-14 started to decline. But testing tooth enamel allows scientists to date the time of birth by the level of carbon-14 taken up by the tooth when it is formed, said Buchholz.
"You measure [carbon-14] content and convert that into a chronological age or date," Buchholz said. Once tooth enamel is formed, the carbon-14 level remains stable, he said.
Remains of six women have been identified in the Gilgo case, but those of an Asian man, a female toddler and two women are unidentified.
Combined with more traditional methods, scientists and police in Canada were able to identify the cranium of a child found in a riverbed in 1968. Experts believed it came from a boy around 7 to 9 years old. But carbon-14 dating of two teeth gave a more precise birth date and age of about 41/2 years, which narrowed the search to match a relative through DNA, Lawrence Livermore officials said.
"We were effectively at a standstill," police superintendant John House said last week.
But after House learned of bomb-pulse dating, scientists at the lab and the Karolinska Institute in Sweden determined the man was born around 1958, give or take 2.3 years. Additional tests found the victim likely once lived in the Northeastern U.S. That probe continues.