Profile distribution and soil health implication of some oxides in agrarian soils overlying geologic formations in Southeast Nigeria

This study monitored the concentration and distribution of the oxides of Cr, Ni, Cu, Zn and As in soils overlained by different lithological materials in southeast Nigeria. A 30 × 30 m spatial resolution of digital elevation model guided the selected eight soil profile pits dug for the study. A total of n = 27 soil samples were collected from the eight soil profile pits. Samples were air dried, and milled into 3–4 µm powder and analyzed using X-ray fluorescence. The result revealed that the oxides were irregularly distributed vertically, with the least heavy metal oxides obtained in the Ap horizons. Nevertheless, Cr2O3 was the most dominant and potentially toxic alongside NiO in Ishibori. Also, As2O3 was potentially toxic in most of the studied soils, with those in Ishibori as the most prone. Using multiple linear regression, the prediction was within the acceptable range (R2 > 0.50) except for As. For the prediction function of Cr, fine and coarse sand were negatively correlated with Cr, while CEC was positively correlated with Cu and Zn.