Cadmium, copper, lead and zinc concentrations in hair and toenails of young children and family members: a follow-up study.

In a follow-up study concentrations of cadmium, copper, lead and zinc (measured by atomic absorption spectrometry) in scalp hair and toenail clippings of 47 children (5-9 years) were compared with previous values (2 years earlier). Family members were also monitored. Twenty-five of the children selected have had either high hair values of Cd, Cu, Pb or low hair Zn concentrations or combinations of these (group A) in the first study. Control group comprised 22 children (B). At the follow-up study, there were no more differences between group A and B. Between the first and follow-up study Cd and Pb levels in hair and toenails of group A children declined (geometric means; hair Cd: 265 vs. 111 ng/g; hair Pb: 10.1 vs. 3.8 micrograms/g; toenail Cd: 720 vs. 335 ng/g; toenail Pb 18.5 vs. 5.8 micrograms/g) and hair Zn values increased (54 vs. 103 micrograms/g). Fathers of exposed children had more Cd and Pb in hair and toenails than fathers of control children (hair Cd: 88 vs. 48 ng/g; hair Pb: 4.4 vs. 1.3 micrograms/g; toenail Cd: 46 vs. 23 ng/g; toenail Pb: 1.3 vs. 0.7 microgram/g). No conclusive findings were obtained for Cu. With respect to heavy metal levels of mothers and brothers and sisters there was no uniform pattern. Children < 5 years of age are especially prone to higher Cd, Pb exposure and to lower Zn status compare with older children.