September 3, 2014
by Medical News Today
Our teeth can reveal where we grew up, according to a new study that says 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.
George Kamenov, of the University of Florida, and Brian L. Gulson, of Macquarie University in Sydney, Australia, write about the discovery in the journal Science of the Total Environment.
In their paper, they describe how they used high-precision lead isotope data from modern and historical human teeth to reveal where they came from.
Dr. Kamenov, a geology researcher, says the finding could help the police solve cold cases. For example, testing the teeth in a badly decomposed body could help focus the investigation in a particular geographic area:
Lead is an element that exists in four forms called isotopes. The amount of each isotope differs according to where it is found in the world in rocks, in soil and in ores. So samples of lead taken from different parts of the world will have slightly different proportions of the four isotopes – their lead isotope profiles will differ.
Tooth enamel locks in lead from childhood exposure
Unlike bone, which is always regenerating, tooth enamel develops during childhood and stays there, locking in the unique profile of lead isotopes and preserving them, as Dr. Kamenov explains:
“When you grow up, you record the signal of the local environment. If you move somewhere else, your isotope will be distinct from the local population.”
Lead profiles can distinguish modern from historical teeth
Analyzing lead profiles in teeth can also pinpoint a period – helping to distinguish between modern and historical teeth. Because of mining and the use of lead in gasoline, there is a clear distinction in the type of lead in the environment in modern times compared with earlier centuries.
The author suggest their discovery may also help archaeologists identify early European bodies in New World areas.
Written by Catharine Paddock PhD
Sourced: Medical News Today
For more information visit: http://www.medicalnewstoday.com/articles/280727.php.
The Pb isotopic record of historical to modern human lead exposure, George D. Kamenov and Brian L. Gulson, Science of The Total Environment, published 15 August 2014, DOI: 10.1016/j.scitotenv.2014.05.085, Abstract.
University of Florida news release, accessed 7 August 2014.