IMPACT OF USED MOTOR OIL ON THE SOIL QUALITIES OF ORJI MECHANIC VILLAGE OWERRI, NIGERIA

Abstract

The study investigated the effects of used motor oil on soil physical and chemical variables and their particle size distribution. Two (2) replicate soil samples were collected from  three radial coordinates 50 31.114N 70 02.703E, 50 31.165 N 70 2.670E and 5023.35N 6059.176E  respectively from the auto-mechanic village and agricultural land which serves as control; at depths of 0-15cm and 15-30cm. Standard methods were adopted both for field and laboratory analysis, utilizing  such instruments as Atomic Absorption Spectrometer (model FS 240 Varian), Jewniary, digital pH meter, Refractometer (model E- Line R.ATC- ), lovibond instrument model Cm-21 and mercury-in-built thermometer. Twenty three (23) different soils parameters were analyzed comprising total organic carbon, heavy metals, soil texture and particle size (clay, sand and silt) organic carbon, exchangeable cations (Na, Ca and Mg), conductivity, salinity,  nutrients (N, P, K), bulk density and organic matter. The result indicated a variation at the mechanic site and control point. The pH of the auto-mechanic soils were acidic with the range of 4.3- 5.0 in comparison with the control point which had a mean value of 5.6. Heavy metals had higher values in auto mechanic soils than in the control and their concentration decreased in this trend, Cu 0.940> Hg 0.211> Ni 0.093>  Zn 0.051> Pb 0.021> Cd 0.015 > Ar 0.003; Hg 1.385> Cu 0.853> Ni 0.079> Zn 0.041> Cd 0.04> Pb 0.034> Ar 0.004. This showed that disposal of used motor oil on the soil affected the soil quality negatively. It is therefore; recommended that there should be a legislation to stop the indiscriminate dumping of spent oil and lubricants on the surface of the soil at Orji Mechanic village without treatment prior to disposal.