Reference values for hair minerals of Polish students.

In the present work, reference values for the content of elements in human hair were elaborated. The population chosen for the study was a group of students in Polish urban area, which served as a representative group of a population of 20 years old individuals living in Europe. The content of 36 elements (essential (B, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, P, S, Si, Sn, V, Zn), toxic (Al, As, Cd, Hg, Ni, Pb, Sb, Tl) elements and others (Ag, Ba, Bi, Ce, La, Li, Rb, Sr, Ti, Y, Zr)) was determined in hair sampled from 117 subjects. Hair were digested with nitric acid in microwave oven in closed Teflon bombs and underwent multielemental analysis for the content of macroelements by ICP-OES and for micro- and trace elements by ICP-MS. Reference ranges were determined and considered as the values between 10th and 90th percentile. It was assumed that the values of the extreme low and high 10% in the population reflected mineral imbalance. In the population, a group of females and males was distinguished, and also a group of women which tinted their hair was separated. This enabled to point out the differences in hair mineral content between genders and for tinted and non-tinted hair. Statistical significance of differences was found for several elements, for which separate reference values were elaborated. This concerned the following elements: Ba, Ca, Cu, K, La, Mg, Mn, Si, Sr and Ti. In the interpretation of the level of these elements it is necessary to take into consideration both sex and artificial coloring. Also ratios between elements were evaluated - between nutritive (Ca/Mg, Ca/P, Na/K, Zn/Cu) and nutritive vs. toxic (Zn/Cd, Zn/Pb). In this case the differences were detected only for Ca/P ratio. This shows that perhaps in the future, inter-element ratios rather than the absolute levels of elements would be considered for the interpretation of the results of mineral analysis of hair.