Programmes > Par auteur > Bergmann Christine L.

Elemental Analysis using pXRF to Assess Human Diet and Mobility
Robert Tykot  1, *@  , Christine L. Bergmann  1@  
1 : University of South Florida  (USF)  -  Site web
* : Auteur correspondant

Elemental analysis of human bone to study diet and mobility is an established methodology, yet the number of studies done is relative few when compared to those on carbon, nitrogen, oxygen, and strontium isotopes. Elemental analysis of calcium, iron, barium, strontium, lead, zinc, arsenic and other elements nevertheless can support and supplement isotope-based interpretations, and be of significant use in cases where bone collagen is not preserved, or when only non-destructive methods of analysis are permitted. Most previous elemental studies have been just as destructive as isotope analyses, with samples well-cleaned, ashed, and put into solution for analysis by atomic absorption or ICP spectrometry. Over the last decade, non-destructive portable X-ray fluorescence (pXRF) spectrometers have become widely available to archaeologists. While regularly used for trace element analysis of obsidian and other lithics, and major element composition of metals, it appears potentially useful for studies of skeletal remains as well. Elemental analysis, however, has potential reliability issues due to degradation and contamination of the mineral portion of bone, especially near the surface.

In the United States and other parts of the world, permission to conduct destructive isotope analyses of human skeletal remains has become increasingly limited. In part for that reason, experimental studies using the pXRF have been conducted to test the precision and heterogeneity of bone surfaces and interior, with different amounts and methods of cleaning as well as analytical settings. One of the first studies done was on individuals from inland and coastal sites in Florida, with the small variation in barium and strontium among individuals at each site suggesting little contamination, and the clear differences between the sites most likely due to varying proportions of aquatic food in the diet. This has been followed by analyses of nearly 1000 individuals from many sites in Latin America, Europe, and the United States, most of whom were also analyzed isotopically and with interpretations made about the dietary importance of maize, millet, and aquatic resources with patterns based on sex and status.

The precision of the pXRF on the elements of interest is excellent, and proper calibration is now established for bone and other calcium-based materials, so that direct comparisons may be made with other elemental studies. Also, further studies are being conducted on tooth enamel and roots, to test whether non-destructive analysis may be reliable for assessing childhood diets. Examples from Italy, Peru, and the United States will be presented.


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