Levels of Heavy Metals in Soil Sample from Active Automobile Workshops in Benin City

The evaluation of heavy metals contamination of soils as a means of monitoring the status of the environment for the good of the ecosystem is crucial. Benin city was subdivided into four zones (south east SE, south west SW, north east NE and north west NW) In this study, top soil (TS) and distance top soil (DTS) samples from three hundred and thirty-nine auto repair workshops in Benin City, Nigeria were assessed for physico-chemical properties and heavy metals (HMs), using standard methods. The main soil properties (pH, cation exchange capacity, total organic carbon and particle sizes) were determined for a network of representative sampling sites. The results shows that the average levels of the heavy metals (excluding Fe) in soil samples from within and 30 m away from the automobile workshops in the various zones are 143.1 (88.6), 118.6 (86.9), 129.1 (79.2) and 143.3 (113.0) for SE, SW, NE and NW respectively (the values in bracket represents DTS). When compared with mean concentrations for other cities. The results revealed higher concentrations of heavy metals in topsoil samples than in 30 m away from the epicentre samples. The samples from North West and South East part of the city had higher Cr, Ni, Pb, and Zn contents than samples from the other Locations. All the heavy metals show significant differences in their means across the two sampling locations (TS and DTS). The correlation analysis showed that all the heavy metals were significantly correlated with each other. The principal component analysis produced only one component which accounted for 69.414% of the total variation between the heavy metals