Lead in a victim's teeth could help investigating officers identify the region he/she comes from. It can help archaeologists trace the route of human migration across history.
A study led by University of Florida geology researcher George D. Kamenov showed that trace amounts of lead in modern and historical human teeth can give clues about where they came from.
The paper will be published in the August issue of Science of The Total Environment.
Lead is composed of four variants, called isotopes. The amount of those isotopes fluctuates in different soils and, therefore, regions of the world. By knowing the isotope types in each region, a person can be identified from his teeth contents.
Mining and other pollution-causing activities releases lead into the environment, and it finds its way to the bodies of children when they inhale dust or and ingest soil.
Tooth enamel, which develops during childhood, locks in the lead signals and preserves them. Your local lead type is locked forever in your teeth.
Even different teeth can reveal facts about where the individual spent each part of his growing years! For instance, the first molar enamel forms by age 3, so it provides information about birth and toddler years. Incisor and canine enamel starts later and finishes around age 5, so it gives insight into early childhood. The third molar enamel does not start forming until age 8, so it indicates late childhood.
Lead analysis can also tell what time period a body is from. The natural composition of lead changed over the past century because of mining and the use of leaded gasoline, so there's a clear distinction between modern and historical human exposure.
Using that information, archaeologists can identify early European bodies in New World areas.
While available data for South America overlaps with Europe, American teeth stand out thanks to usage of ores with distinct isotope signals!