Assessing heavy metal exposure in Renaissance Europe using synchrotron microbeam techniques

A number of archaeological studies have used chemical analysis of preserved, human biological tissues to assess the potential exposure of historic figures and ancient populations to heavy metals. Accurately assessing historic levels of heavy-metal body burden for these individuals based on analysis of remnant soft-tissue, hair and bone collected from preserved human remains is often complicated by the potential for post-mortem chemical modifications and contamination of the body and burial site. This study employs high-resolution, synchrotron-based elemental X-ray fluorescence mapping, tomography and absorption spectroscopy of human remains collected in an archaeological context in an effort to discriminate between heavy metals such as mercury and lead that may have been incorporated through either endogenous or exogenous processes. These methods were used to analyze bone and hair samples from Ferrante II of Aragon, King of Naples (1469-1496) and Isabella of Aragon, Duchess of Milan (1470-1524). These individuals are likely to have been exposed to generally similar levels of heavy metals in their lifetime, would have been embalmed using similar methods and the post-mortem exposure to contaminants is likely to have been similar. Although the remains from both Ferrante II of Aragon and Isabella of Aragon contain high amounts of mercury and lead, the high-resolution and -sensitivity synchrotron microprobe techniques employed in this study provide insight in to the likelihood these metals were incorporated pre-mortem rather than as ante-mortem contaminants. Although synchrotron X-ray fluorescence mapping and tomography are generally consistent with measured mercury from Isabella hair samples being endogenous in nature, the high levels of mercury seen in Ferrante II's remains are most likely related to post-mortem embalming of the corpse. However, application of microfocused X-ray fluorescence compositional mapping and lead L₂ edge X-ray absorption spectroscopy to bone samples collected from Ferrante II show that the measured lead is likely endogenous and the result of in-life exposure to this heavy metal.