Major and trace elements in spruce needles by NAA.
Concentrations of 23 elements in needles of Norway spruce (P. abies) have been determined at 47 sites. It is shown that a thorough removal of the aerosols sitting on the needles surface is necessary in order to get the inherent needle concentrations. Neutron activation was used to determine concentrations from 10(-9) to 10(-2) g/g. Irradiation and counting conditions are given. The essential elements, Ca, Cl, Cu, Fe, K, Mg, Mn, P, Zn, and the nonessential elements, Al, As, Ba, Br, Co, Cs, Hg, La, Na, Rb, Sb, Sc, Sr, and V, could be determined. The concentrations of most elements are about a factor of 6 smaller than the mean concentrations in land plants. Analytical reproducibility was much better than the variation among individual trees, and the variation within sites is smaller than among sites. In general, essential elements have smaller variations than nonessential elements. For some elements, variations between sites are owing to differences in the soil pH or the emission situation.