Lead isotope data can be compared to the levels of lead found in our teeth, which becomes trapped in the dentin as teeth develop and then lock in the material. ?As our tooth enamel develops, it locks in the isotope composition of the lead we have been exposed to in childhood. And as human activity that generates lead pollution varies around the world, so do the profiles of lead isotopes in the environment.?
This information could be used to help police solve cases that have gone cold, as a decomposing body would still provide enough lead from the teeth to pinpoint a geographic location. "We can use this pollution signal to figure out where these people came from," Dr. Kamenov said. ?Also, say the authors, because different teeth develop at different times in childhood, they can show if a person moved around in their childhood.?
?For instance, the enamel in first molar teeth has finished forming by the age of 3, and reveals where that person was from birth through toddler years.?
?Enamel in incisor and canine teeth begins to form later and finishes around age 5, giving clues about residency in early childhood, and third molar enamel does not finish until age 8, giving clues about later childhood years.?
The findings can also be used to identify where individuals originally come from, as they note that teeth from the United States are distinct from any other region around the world. You can go back in time, look at archaeological sites and try to reconstruct human migration," Dr. Kamenov said.