Comparative Assessment of Portable X-ray Fluorescence and Atomic Absorption Spectrophotometry for Metal Analysis in Urban Dumpsite Soils of Ibadan, Nigeria

Accurate assessment of metal concentrations in soils is essential for environmental monitoring and risk evaluation. Portable X-ray fluorescence (p-XRF) has emerged as a rapid, non-destructive technique for elemental analysis, whereas atomic absorption spectrophotometry (AAS) remains the standard method for trace metal determination due to its superior sensitivity and precision. This study compares the analytical performance of p-XRF and AAS in quantifying trace and major metals in urban dumpsite soils from Ibadan, Oyo State, Nigeria. Concentrations of calcium (Ca), copper (Cu), zinc (Zn), chromium (Cr), lead (Pb), nickel (Ni), and iron (Fe) were measured using both methods. Statistical comparisons using paired t-tests indicated significant differences in the concentrations of Ca, Cr, and Ni between p-XRF and AAS, while no significant differences were observed for Cu, Zn, Pb, and Fe. Pearson correlation analysis revealed a very strong positive correlation for Ca (r = 0.950, p < .001) and a moderate correlation for Fe (r = 0.691, p = .013), but weak or negligible correlations for other elements. The findings suggest that p-XRF can serve as a reliable alternative to AAS for determining major metals such as Ca and Fe, offering advantages in speed and field applicability. However, its use for trace metal quantification in complex soil matrices remains limited and requires calibration against matrix-matched standards and validation with reference methods such as AAS.