LEAD EXCHANGE IN TEETH AND BONE - A PILOT-STUDY USING STABLE LEAD ISOTOPES

Stable lead isotopes and lead concentrations were measured in the enam el and dentine of permanent (n = 37) and deciduous teeth (n = 14) from 47 European immigrants to Australia to determine whether lead exchang e occurs in teeth and how it relates to lead exchange in bone. Enamel exhibits no exchange of its European-origin lead with lead from the Au stralian environment. In contrast, dentine lead exchanges with Austral ian lead to the extent of similar to 1% per year. In one subject, trab ecular bone from the tooth socket exchanged almost all its European le ad with Australian lead over a 15-year period (turnover of similar to 6% per year), similar to the similar to 8% per year proposed for lead turnover in trabecular bone. The repository characteristics of intact circumpulpal dentine were investigated by analyses of four sets of con tiguous slices from six teeth: 1) a set consisting of slices with inta ct circumpulpal dentine and cementum; 2) a set in which these areas we re removed; 3) another set consisting of slices with intact circumpulp al dentine and cementum; and 4) a set without cementum. These analyses show relatively small differences in isotopic composition between con tiguous slices except that circumpulpal dentine appears to be tile dom inant control on lead concentration. There is a significant correlatio n (R-2 = 0.19, p = 0.01, n = 34) of dentine lead concentration and rat e of exchange with residence time from the country of origin and Austr alian lead, but there is no such correlation with enamel lead concentr ation. Analyses of permanent and deciduous teeth of subjects from othe r-countries who have resided in Australia for varying lengths of time should resolve some of the questions arising from this pilot study.