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

Anegbe Bala,Emina Rosemary Anwuli,Ugbune Ufuoma,Okieimen Felix Ebhodaghe,Okuo James Majebi

doi:10.11648/j.ijec.20190301.12

Anegbe Bala, Emina Rosemary Anwuli + Show 3 more

Open Access

https://doi.org/10.11648/j.ijec.20190301.12

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Abstract

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.

Highlights

During the last decades of the twentieth century there was an awareness of the importance of the soil as an environmental component and recognition of the need to maintain or improve its capacity to allow it to perform its various functions [1]
The local utilization of engine oil in Benin City has increased in recent time this is due to the upsurge in the number of vehicles due to ever-increasing demand for personal vehicles, most of which are used “Tokunbo” vehicles and other machines that makes use of these lubricants
Presence of residual hydrocarbon spills and oil may have had some direct impact in lowering the pH of the soil samples

Summary

Introduction

During the last decades of the twentieth century there was an awareness of the importance of the soil as an environmental component and recognition of the need to maintain or improve its capacity to allow it to perform its various functions [1]. The local utilization of engine oil in Benin City has increased in recent time this is due to the upsurge in the number of vehicles due to ever-increasing demand for personal vehicles, most of which are used “Tokunbo” vehicles and other machines that makes use of these lubricants These unguided practices have worsened the rate at which used engine oils spread and contaminate the soils and water around the town. The aim of this research is to obtain a representative soil sample and evaluate the contribution of the activities of automobile workshops to heavy metals load in soils, as well as their horizontal migration from different zones in Benin City

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