Bone analysis: Silent testimony of lead exposures in the past

Abstract

Modern-day environmental pollution by lead results in considerable adverse health effects. Increased lead exposures are a result of modern technology, and pre-industrial exposures were presumably very low. This possibility may be examined by analysis of mummified human tissues from the past. Bone samples are particularly well suited for this purpose, because the skeleton contains most of the body burden of lead, and because well preserved bone tissue is unlikely to be contaminated post mortem. Trabecular bone from a lumbar vertebral body was taken from each of the mummified bodies from Qilakitsoq, except for the youngest child.

The lead concentrations were determined by atomic absorption spectrometry with routine procedures against laboratory contamination. The lead levels varied between 0.12 and 0.30 11g/g dry weight with a median of 0.21 μg/g. Although slightly lower levels may be obtained by using more rigorous clean-laboratory techniques, the results found are similar to minimal levels measured in bone tissue from Nubians of Northern Sudan and Precolumbian Peruvians. Thus, the Qilakitsoq Eskimos lived in a pristine environment low in lead. This result offers an independent indication that modern-day lead exposures are considerably in excess of base-line levels to which humans have originally adapted.