Establishment of natural background concentration of some elements in soils from Zaria and environ by INAA using NIRR-1

Source profile of chemical elements is important both for determination of natural baseline and anthropogenic input into soil characteristics. Undisturbed soils in Zaria and environ were sampled at six locations namely Bassawa, Kufena, TSibiri, Palladan, Kamphaghi and Kudingi based on the geology of the area. The soil samples were analyzed for sixteen (16) elements using Instrumental Neutron Activation Analysis (INAA) Technique. The elements determined were AI, Mn, Dy, K, Br, La, Sc, Cr, Fe, Co, Rb, Cs, Ba, Eu, Lu and Ta. Analysis of the data revealed that concentration of most of the elements determined increases with depth indicating that natural sources account for the distribution pattern. In addition, soil samples collected in areas underlain by igneous rocks contain high concentrations of AI and Dy in 0-15 cm fraction and K, La, Rb and Mn in 0-30 cm fraction when compared with soil samples collected in areas underlain by metamorphic rocks. On the other hand, soil collected from the areas underlain by metamorphic rocks are more enriched in Sc and Cr in the 0-15 cm fraction and Sc and Co in the 0-30 cm fraction compared with soil collected from areas underlain by igneous rocks. The general variations in the elemental concentration of the various soil samples is attributed to the differences in parent rock chemistry and constituent minerals, local variation in Eh-pH conditions of the environment and continued alterations by other soil forming factors.