Advantages of the use of deciduous teeth, hair, and blood analysis for lead and cadmium bio-monitoring in children. A study of 6-year-old children from Krakow (Poland).

The population of about 300 6-year-old preschool children was studied for lead (Pb) and cadmium (Cd) in deciduous teeth, scalp hair, and capillary blood. Zinc (Zn) content in hair was also measured due to its possible interferences with the elements studied. The Pb and Cd contents were measured by graphite furnace atomic absorption spectrometry with Zeeman background correction, and Zn, by flame method. Metal levels found were comparable to those in European countries. Positive correlations between Pb and Cd in the same and different tissues were widespread (r=0.23-0.68). A positive correlation was found between Pb in teeth and blood (r=0.65, p<0.001). Pb blood threshold 100 μg L(-1) referred to 2.6 μg g(-1) Pb in teeth. Predictability of this Pb teeth limit was 14% vs. 5% for Pb blood. Strong negative correlation was found between hair Pb and Zn (r=-0.68, p<0.001). Enhanced Cd and Zn levels in hair were associated with the household drinking water hardness. The associations with some other environmental and behavioral factors were also presented and discussed. The results proved the advantage of analysis of primary teeth for Pb exposure screening of preschool children.