Lead post-mortem intake in human bones of ancient populations by (109)Cd-based X-ray fluorescence and EDXRF

In this work we measured the lead concentration in human bones of Middle Age by means of a portable X-ray fluorescence system based on ¹⁰⁹Cd radioactive source. The detection system consists on a Ge hyperpure detector. This system, conceived for in vivo Pb analysis in bone, is portable, non-destructive and is based on lead K lines detection.

The analysed bones are part of two collections of bones both from the end of Middle Age and submitted for some years to a lead polluted burial environment. The bones of one collection were buried initially on the soil in a convent, in Lisbon (Portugal) and further on, kept in a lead coffin for around 100 years. The second collection contains bones buried permanently on the soil around an old church on the south of Portugal. This place became a parking car for around 20 years.

In this work we studied the distribution of Pb in cortical bone, and trabecular regions from the outside surface to the inner part of the bone and the results are compared with the obtained ones by energy dispersive X-ray fluorescence (EDXRF).

The obtained values present a strong contamination of Pb in spongy bones kept in the lead coffin with concentrations ranging from 250 to 350 μg Pb/g bone mineral, and 4 to 7 μg Pb/g bone mineral for bones buried in the soil. Good agreement was observed between the results obtained by the two techniques.