Geochemical distribution of major and trace elements in hydromorphic soil profiles developed on recent alluvium

Abstract

Geochemical composition and distribution of major elements study is vital in terms of investigating the major soil forming compounds and to know the fate of trace elements in soils. Particle size distribution (PSD), pH, organic carbon (OC), and major and trace elements of hydromorphic soils formed on recent alluvium in Obafemi-Owode Local Government Area of Ogun state, Nigeria were analysed using standard procedures. Three profiles pits were dug based on the mapping units identified, and samples were collected for laboratory analysis. Data were subjected descriptive statistics and Pearson’ correlation coefficients using IBM SPSS version 27. The PSD was dominated by sand content, followed by clay and silt, and soil pH in KCl was strongly acid (3.17–4.30) and pH in H₂O was moderately acid (4.74–5.80), while OC contents were low to moderate (1.22–6.69 g/kg). The major elemental results showed higher concentration of SiO₂ (>50 %) connotes presence quartz, feldspar, and clay minerals. Manganese, Cu, Ba, Zr, and Zn have higher concentrations among the trace elements. Major elements ratios (SiO₂/Al₂O_3, K₂O/Al₂O₃) showed moderate weathering stage, while trace elements ratios (Ni/Co and Cu/Zn) revealed deposition under humid conditions and anoxic environment. The statistical analysis revealed that most elements have skewness closed to zero except MgO and K₂O. Correlation coefficients between the elements are positive and significant (p < 0.05 and p < 0.01) indicating that their presence can be accounted for by similar lithology, though some have negative relationship which could be as a result of anthropogenic activities. The study found that elements were potential tracers for the presence of human activities and environmental changes.