Lead isotope ratios: Tracking the migration of European‐Americans to Grafton, Illinois in the 19th century

Abstract

ABSTRACTLead isotope analysis was conducted using inductively coupled plasma mass spectrometer (ICP‐MS) instruments on local soil samples and human premolar tooth enamel from a 19th century population from Grafton, Illinois, USA. The goal of the study was to determine if lead isotope analysis could be used to infer place of birth and patterns of 19th century migration into the city of Grafton. Five soil core samples from a location near Grafton, Illinois, five grave soil samples from the city cemetery and the tooth enamel of 19 human premolars were analysed. The results of the soil core analysis indicated that the lead isotopic signature of Grafton differs significantly from isotope ratios of other geographic areas associated with recorded places of birth of 19th century Jersey County residents. Elemental and isotope analysis of the soil samples indicated that diagenesis was not a factor in the analysis of lead isotopic signatures of enamel. From the lead isotope analysis of human premolars, the geographic origin of 13 of the remaining 15 individuals could be inferred. The inferred geographic origin was supplemented by an analysis of 1860 mortality and census records and demonstrated the utility of using lead isotope analysis in bio‐archaeological investigations. Copyright © 2010 John Wiley & Sons, Ltd.