To systematically study the partition of environmental metals including lead, mercury, and cadmium and essential minerals such as iron, manganese, copper, and zinc in the maternal/fetal unit of healthy pregnant women, we analyzed blood and umbilical cord blood samples of 50 healthy mother/child pairs using a biomonitoring approach. The levels of essential minerals in healthy pregnant women were significantly different from those of the general population. The partition of essential minerals and environmental metals and their associations between maternal and umbilical cord blood were metal-specific. Lead entered the fetal environment nearly unaffected. The median fetal level was only 10 % lower than the corresponding maternal concentration (10.3 vs. 11.5 ?g/l, P = 0.0038). Mercury accumulated in the fetal unit resulting in more than a threefold increase in fetal compared to maternal exposure (1.48 vs. 0.44 ?g/l, P <0.0001). In contrast, placental transfer of Cd was limited, and median fetal exposure was
