Sometimes the dead do give up their secrets. Lead analysis of a human tooth can offer valuable clues to a person’s origins, according to an article by Reuters, information that can aid criminal investigators and archeologists working with old or decomposed corpses. Analyzing a tooth’s lead content can determine where a person grew up, says University of Florida researcher George Kamenov, because lead ore deposits around the world differ and teeth will absorb traces of metal from their environment. Leaded gasoline used from the 1920s through 1980s also leaves its calling card on tooth chemistry and can help identify a body’s age, according to Kamenov, who has used lead analysis with law enforcement working on cold cases.
Oxygen in the bones and other chemical elements in the hair and nails also provide geographic clues but their usefulness has time limits. Bones regenerate every seven to ten years, according to the article, so they can shed light on the past decade while teeth and nails hold answers only from a person’s last few months.