Assessment of lead exposure of children from K-XRF measurements of shed teeth.

Lead is accumulated and immobilized for long periods of time in teeth. Thus the Pb concentration of a tooth can be used as an indicator of the cumulative Pb intake of a child. Shed and extracted teeth were collected from children in Beijing, China and some industrial regions in the Middle Urals in Russia. The Pb levels in the teeth were measured in Philadelphia, PA using an X-ray fluorescence (XRF) technique. Since Pb deposits in the tooth during the entire period that it is in the child, the measured tooth Pb level was divided by the age of the child when the tooth was shed and expressed in terms of (microgram/g-yr). 10% (n = 100) of the teeth from Beijing, China had Pb levels exceeding 5.5 and 3% above 9 micrograms/g-yr. For comparison, in the 1970s when urban environmental Pb levels were elevated, the tooth Pb levels in Philadelphia children were similar, i.e. 10% (n = 298) of the teeth had Pb levels exceeding 7.5 and 6% were above 9 micrograms/g-yr. Children in a more rural setting, Bennington, VT, had no detectable tooth Pb (n = 200). The Pb levels in the teeth from the Urals were much higher; 50% (n = 134) of the teeth had Pb levels exceeding 7.5 and 10% exceeding 17.8 micrograms/g-yr. The tooth Pb levels observed in the teeth from Beijing, and more so from the Urals, indicate that these children are residing in Pb polluted environments. Further studies are required to determine the extent of the Pb pollution and to explore the possibility that there are associated Pb-related health deficits.