Mapping on pollution of agricultural soil as a proxy by means of magnetic susceptibility and morphological measurements in some parts of Kebbi State, northwest Nigeria

Abstract

Magnetic susceptibility (MS) and morphological measurements were carried out on sur
face soil samples in order to find a possible relationship and to obtain environmental 
implications. The samples were taken along the two parcel roads of Maidahini (A–B) and 
Bunza (C–D) on a square grid of 400 × 400 m2 near the agricultural irrigation farmland 
soil close to the main city of Bunza area in Gwandu formation, northwestern Nigeria. MS 
distribution values ranged between 5.756 × 10−6 SI to 4.0 × 10−6 SI and 2.65 × 10−6 SI to 1.2 
× 10−6 SI, from the two parcel roads. Geochemical analysis by means of atomic absorption 
spectrometry shows that the concentration of various heavy elements was higher than 
the mean background values for world soils. However, in view of the high values, espe
cially that apparent mineralization was observed on each sample, the results were there
fore due to the proper calibration of the equivalent used for the analysis soil samples. 
Spatial histogram distribution of MS shows the variation in high and low susceptibility 
concentrations and relate to toxic content reported near the rivers. Urban pollution and 
road traffic emission seem to be the main influence for these values. The results showed 
that magnetic measurements are sensitive, fast, inexpensive, and robust, which can be 
advantageously applied for studying soils affected by urban and road pollution. Thus, the 
study has shown that the mean spatial distribution concentrations of Fe, Mn, Cu, Ni, and 
Cr content were 2,378.9, 107.3, 72.8, 53.6, and 6.5, which were very high in top soil sam
ples across the two parcel roads of Maidahini (A–B) and Bunza (C–D).