A powdered intercomparison material for trace element studies was prepared from human scalp hair and distributed to more than
100 laboratories of which 66 reported results for altogether more than 40 elements. By statistical evaluation of these data
certified concentration values were derived for 20 elements, namely As, Au, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, Mg, Mn, Na,
Pb, S, Sb, Se, Sr and Zn. The data also made it possible to compare different methods of analysis and to judge the value of
different levels of experience on the part of the analyst concerned; these comparisons are presented here with special reference
to the elements As, Cd, Hg, Pb and Sb.