Quantitative evaluation of ante-mortem lead in human remains of the 18th century by triaxial geometry and bench top micro X-ray fluorescence spectrometry

Abstract

The aim of this work is to demonstrate the suitability of the commercial benchtop micro X-ray fluorescence (μ-XRF) system M4 Tornado, to evaluate the differences in lead distribution in different bone and tooth structures. Ante-mortem and post-mortem Pb accumulation was also assessed and the lead amount in different tissues was compared. Micro-XRF based on polycapillary systems is a relatively new technique with capabilities to provide multielemental maps and quantitative measurements. Another advantage of the technique is being non-destructive and requiring only a small amount of sample. In this work, we measured the lead concentration in human remains, bone and tooth of an 18^th century young male subject, around 30 years old, and compared the results obtained using μ-XRF with a setup with a triaxial geometry. Accuracy of the microanalytical system for pressed pellets and cross-sections of bone and tooth was also certified. The μ-XRF setup provided analytical point spectra, line profiles and elemental maps for Pb and Ca distribution in bone and tooth. The quantitative calculations were performed by the fundamental parameter and compare mode methods. The accuracy and the detection limits were checked using standard reference materials for Ca, Zn, Sr and Pb. Furthermore, unusual extremely high amounts of Pb in cortical bone, tibia and fibula were observed, reaching 120 ± 10 μg g⁻¹, while the trabecular region reached 250 ± 20 μg g⁻¹. Rib presented the highest levels, 560 ± 30 μg g⁻¹. In the tooth structure, the highest amount of Pb was found in pulp and root with 130 ± 50 μg g⁻¹. Low levels of Pb in the surrounding soil have been found.