Determination of rare earth contents in plant and soil by Neutron Activation Analysis (NAA)

Soil and plant samples originating from the southern part of Germany are investigated to determine the concentrations of rare earth elements. In soils, 9 rare earth elements (Ce, Dy, Eu, La, Lu, Nd, Sm, Tb, Yb) are analysed by Instrumental Neutron Activation Analysis (INAA). In biological material (grassland, needle and wheat grains), the rare earth elemental concentrations are much lower, so a radiochemical separation is needed in order to remove or reduce the main interferences like Br, K, Cr, Fe, Zn etc. This technique, Radiochemical Neutron Activation Analysis (RNAA), makes it possible to determine 8 rare earth elements (Ce, Eu, La, Lu, Nd, Sm, Tb, Yb) in biological material. At various sampling sites both grassland and soil samples were taken. For these places transfer ratios for the rare earth elements are calculated. They show no significant enrichment of any of the rare earth elements, except two sites where Nd shows higher and Sm lower concentrations than expected.