The determination of lead in human teeth

The effects of lead poisoning may be much more extensive than had been realised until recently. Industrial workers and the inhabitants of big cities are continuously absorbing small quantities and it is important to be able to detect excessive amounts over long periods. This can be done by examining teeth which have been extracted for other reasons. Tooth sections have been bombarded with 3He ions from the Birmingham 152 cm cyclotron. Several alpha-emitting isotopes of polonium are produced from any lead present. After bombardment the sections are held against an alpha-sensitive plastic track detector for a few days. Examination of the plastic then shows a distribution of tracks proportional to the distribution of lead in the tooth. Standards irradiated at the same time enable us to determine the absolute concentration. It is found that the concentration in the absorbed enamel records the lead absorbed during the time of the formation of the tooth while that in pulpal dentine shows the integrated take-up during the life of the tooth. (orig.)