AN INVESTIGATION OF THE CHEMICAL SPECIATION OF PB AND ZN IN HUMAN DECIDUOUS TEETH

Abstract

It has been shown that element concentrations in human deciduous teeth can demarcate exposure to that element for a developing child. The aim of this study was to investigate the interaction of the toxic metal lead (Pb) and other elements in the bloodstream with biologic hydroxyapatite, a central component of human deciduous teeth, with attention to their chemical speciation. Synthetic Pb-hydroxyapatite samples and deciduous teeth samples were analyzed via thermodynamic parameters, X-ray fluorescence (XRF), and X-ray absorption near edge structures (XANES) spectroscopy to determine Pb speciation, zinc (Zn) speciation, and the interactions of other elements. Pb substitution into the biologic hydroxyapatite and resulting pyromorphite precipitation was characterized. Additionally, we found possible Zn coprecipitation with biologic hydroxyapatite during tooth formation in the fetal stage. This research can be used to predict toxic metal concentration in a child's blood based on toxic metal concentration in human deciduous teeth and is relevant to the detection of toxic metals in a child's environment.