Regional insights into childhood lead exposure from historical North American skeletal remains

Lead (Pb) concentration and isotope analyses of human remains have been used to examine differences in Pb exposure to examine the movement of peoples and Pb-containing cultural materials. The thesis reviewed 55 bioarchaeological studies of Pb concentrations and isotope analyses of teeth and identified limitations in the archaeological, ethnographic, and historical documentation, and variability in tooth choice and analytical approach that complicate transparency and interpretation. Early fishing settlements (17ᵗʰ to 19ᵗʰ century) in Newfoundland and Nova Scotia lacked local anthropogenic Pb exposure. Pb concentrations in tooth enamel of 46 individuals from St. Paul’s Anglican Church (Harbour Grace), Foxtrap-2 (Foxtrap), Wester Point (Portugal Cove-St. Philip’s), Tors Cove, St. Luke’s Anglican Church (Placentia), and Block-3 (Louisbourg) cemeteries ranged from 0.1 to 28.9 ppm. These were compared to 19 individuals associated with the mid-18ᵗʰ-century St. John’s Royal Naval cemetery, Newfoundland who showed levels that ranged from 0.2 to 24.6 ppm. These levels showed that childhood exposures to Pb in these early fishing communities was as much as 20 times higher than expected, suggesting anthropogenic Pb sources were available in the absence of local mining. Although there were many potential imported Pb-containing products available to the fishers, ceramic materials were known to have a Pb glaze and are frequently found on archaeological sites. Ferryland and Anse à Bertrand were associated with English and French fisheries, respectively, and Pb concentrations of 23 ceramic glazes analyzed from these sites ranged from 28.3% to 58.9% Pb. Pb isotope ratios in both the ceramic glazes and human tooth enamel showed a strong association with isotope ratios of English/Welsh and Western European ore sources during the 17ᵗʰ to 18ᵗʰ centuries. However, individual outliers, including one born in Newfoundland, showed evidence of exposure to American Pb ore. The “de-focusing” of values in the 19ᵗʰ century as American Pb-containing products were exported highlight challenges with associating isotope ratios to cultural affiliation. This study contributes to understanding the roles of the physical versus the cultural environments in Pb exposure and emphasizes the importance of considering contributions from both environmental and cultural sources when interpreting exposure data, migration, and cultural histories.