Concentration of Heavy Metals in the Soils near Some Mechanic Villages in Abeokuta Metropolis, Ogun State, Nigeria.

Abstract

Soils and water bodies near auto mechanic village (MV) contain heavy metals, which pollute the environments and are hazardous to human and environmental health. Assessment of heavy metal concentration in three replicate soil and water samples from three MVs (Fajol, Id-Aba and Kotopo) in Abeokuta metropolis in Nigeria was conducted. Heavy metal concentrations in topsoil of the MVs showed copper ranging from 0.02 mgkg^-1 in the topsoil at Idi-Aba MV to 126.89 mgkg^-1 for topsoil at Kotopo MV. The level of copper detected in Kotopo MV soil is however higher than the allowable limits for Sweden, Netherlands and Germany. Mean concentration of zinc in soils of the MVs were 2.89, 0.91 and 86.23 mgkg^-1 respectively for Fajol, Idi-Aba and Kotopo MV respectively. Metal enrichment factor indicated that the contamination degree ranged from unpolluted to moderately polluted areas. Copper is the most enriched metal in the soil of the MVs especially at Kotopo MV. Relative abundance of the metals in the topsoil (0-15cm) in Fajol MV follow the order Zn > Ni> Cr >Pb >Cu > Co> Cd.  For the Idi-Aba MV, relative abundance is in the order Ni > Zn > Cr > Pb> Cu > Co and Cd, and that of Kotopo MV was Cu >Zn> Pb > Ni > Cr, Co and Cd. Mean heavy metal in the water samples were lower than those found in the soils of the MVs. Stream water near the Kotopo MV had the highest concentration of most metals. Zinc had the highest mean concentration of 2.02 mgL^-1 while copper was 1.09 mgL^-1.  There is an urgent need to put measures in place to monitor the activities in these MVs in order to safeguard peoples’ health environmental integrity.