Quantified Retrospective Biomonitoring of Fetal and Infant Element Exposure using LA-ICP-MS Analysis of Deciduous Dentin in Three Contrasting Human Cohorts.

What the science says:

• We used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of dentin in baby teeth to reconstruct personal histories of toxic metal exposure, an approach that has been increasingly used over the last decade in environmental epidemiological studies.
• Absolute quantification (use of a standard reference material as a calibrant to convert raw data into parts per million) has largely not been used in studies because matrix-matched standards for this technique are not commercially available
• We used a pressed pellet of a NIST 1496 (Bone meal) certified standard reference material as a calibrant to convert data into parts per million
• We compared data from tooth specimens collected from three different populations; one of which when environmental lead concentrations were higher, to test whether absolute quantification could show this difference

We found that tooth lead levels were much higher in the St. Louis Baby Tooth Study teeth compared to those from children in present day rural Nigeria and present-day rural US (which were the lowest). See the figure below.

The height of the bars represents the average tooth lead concentration (burgundy for prenatal and blue for postnatal portions of the teeth) and the black lines show the standard deviation around the average. The bars are superimposed on a close-up image of one tooth section with circles showing where the laser ablated tooth material to take measurements in the dentin of the tooth.