Man, nutrition and mobility: A comparison of teeth and bone from the Medieval era and the present from Pb and Sr isotopes

Naturally occurring isotopic systems, such as strontium (Sr) and lead (Pb), are very useful for characterizing different sources and to produce backgr ound information. Norwegian teeth from the Medieval era have Pb-206/Pb-204 ratios between 18.8 and 18.2, in comparison with present day ratios of betw een 18.0 and 17.6 showing the impact of Pb from modern industrialization an d from traffic. Sr analyses of Medieval teeth show that an individual livin g in a coastal town on the west coast of Norway can easily be distinguished from one in a rural area at that time. The Sr signature shows that Medieva l people lived on local products while present people to a greater degree l ive on imported or domestic industrially processed food. Medieval and moder n teeth from one site give similar Pb signatures and concentrations indicat ing no increase in pollution over time. However, the impact of industrial p ollution can be seen from Pb analyses on contemporary teeth, so that the me thod can be used to monitor emission of heavy metals from local industry. W hilst the Pb and Sr natural isotopic systems individually provide valuable information, a combination of the two techniques is a very powerful tool in environmental and archaeological research. (C) 1998 Elsevier Science B.V. All rights reserved.