Quantitative determination of heavy metals around schools and automobile workshops near frequented roads in Kaduna State, Nigeria

Abstract

Heavy metals are metallic elements with high density compared to other metals and are toxic even at minute concentrations. The concentration of these metals around schools and automobile workshops near frequented roads in Kaduna State, Nigeria, was reported in the present work. Soil samples were collected at varying distances from the major roads (0 – 10m) and at different depths (0 – 60cm). The elemental composition of the samples was determined using Next-Generation Cartesian Geometry Energy Dispersive X-Ray Fluorescence Spectrometer (NEX CG EDXRF) and the statistical correlation and clustering analysis were carried out using SPSS and Mini tab, respectively. The heavy metals Sn, Hf, Ta, V, Cr, Zn, Ir, Pt, Au, Mn, Fe, Co, Ni, Cu, Pb, Th, Ga, As, U, and Zr were considered in the analysis, and their concentrations were presented as Average ± standard deviation. Pearson correlation coefficient indicated different levels of relationships among the heavy metals, while Clustering analysis grouped the soil samples into three major clusters, further confirming the interrelationship among the samples. The concentrations of As, Pb, Cd, Co, Ni were found to be of serious health concern, considering that in almost all the zones in Kaduna state, their average concentrations were greater than the threshold provided by WHO/FAO. Findings from this study indicated that it is unsafe for children to play near schools /auto-mechanic workshops located along highways.