Human tooth enamel as a record of the comparative lead exposure of prehistoric and modern people

There is a considerable body of evidence to support the contention that the atmospheric Pb burden is now considerably greater than it was in the remot e past. However, as there are a diversity of potential environmental pathwa ys leading to Pb ingestion, it is not clear how atmospheric Pb levels relat e to human exposure. It is necessary to establish a baseline for human expo sure to Pb from natural sources in the pre-metallurgical past, with which c ontemporary exposure can be compared. This paper addresses this issue by co mparing the Pb content of human dental enamel - an established proxy for Pb exposure - from modern and archaeological, pre-metallurgical individuals u sing thermal and plasma ionisation mass spectrometry. It is shown that mean Neolithic enamel Pb contents are approximately 0.31 +/- 0.04 ppm. These va lues are only one order of magnitude lower than previously reported data fo r the same tissues for modern juveniles, despite an established 400-fold in crease in the atmospheric Pb burden. The results suggest that 'natural' exp osure to Pb in food and water may have been higher than previously thought, and that the link between atmospheric Pb and human exposure warrants furth er investigation. (C) 2000 Elsevier Science B.V. All rights reserved.