Effect of Spent Engine Oil Discharge on Soil Properties in Selected Automobile Workshop in Calabar , Cross River State , Nigeria *

This research was carried out to investigate the effect of spent engine oil (SEO) discharge on soil properties and heavy metal concentrations in selected automobile workshops in Calabar, Cross River State, Nigeria. Soil samples were collected from four different automobile workshops (Atimbo, Etta-Agbor, Elijah Henshaw and Satellite town) in Calabar. Three sampling points were mapped out around each mechanic workshop. The soils were loamy sand and strongly acid. In all the locations, the highest pH values, organic carbon, total nitrogen and available phosphorus were at the point of discharge of the SEO while the exchangeable bases varied across all the locations. Lead, copper and cadmium were higher than the permissible limits whereas iron, manganese and zinc concentrations were below the permissible limits in the studied sites. Spent engine oil should be properly disposed of to avoid heavy metals toxicity in the soil as most of these metals are leached down the profile thereby polluting underground waters which in turn is dangerous to human health.