Synchrotron radiation micro X-Ray Fluorescence (SR-μXRF) elemental mapping of ancient hair: Metals and health at 3rd millennium BCE Shahr-i Sokhta, Iran

Abstract

Only a handful of studies using synchrotron radiation enabled approaches to ancient human hair have been undertaken to date, few studies explore metal element distribution within ancient hair, and none Cu in particular. This paper shows how key archaeological questions, such as effects of intensive metal and craft work on human health, can be investigated using synchrotron radiation micro X-Ray Fluorescence (SR-μXRF) in exploring biogenic versus diagenetic/environmental uptake of metals, and copper in particular, in ancient human hair. The ID21 scanning X-ray microscope optimized for 2D μXRF (elemental maps) was used at the ESRF (European Synchrotron Radiation Facility) to obtain detailed elemental maps, including Cu, in ancient hair sections (10 μm) of eight individuals (n = 8), as well as modern hair controls (n = 2). Differentiation in the levels of Cu were discovered between different skeletal individuals from the site of Shahr-i Sokhta, a 3rd millennium BCE large urban site with intensive metalwork and other craft work activities in ancient Iran. In particular, hair of a young female showed elevated levels of Cu, with highest values distributed within the cortex. This distribution of elevated levels of Cu, together with contextual data, points to biogenic, rather than diagenetic/environmental source for the uptake of Cu.