Properties of Soils and Plants Uptake within the Vicinity of Selected Automobile Workshops in Ile-Ife Southwestern, Nigeria

Abstract

Backyard farming is becoming popular among the auto mechanics near their workshops where spent engine oil and carcass of vehicles are continuously dumped in Nigeria. The properties of soil and maize plants sampled from the vicinity of selected auto mechanic workshops in Ile-Ife, Nigeria were investigated. The results showed that heavy metal contents in the soils from the sampled sites were (range, mg kg-1) Fe 1238.12 to 1564.25, Zn 18.10 to 24.75, Pb 1.21 to 3.43 and Hg 0.48 to 0.74. These values were significantly (P< 0.05) higher than the control (non auto mechanic site) with Fe 37.50, Zn 0.70, Pb 0.15 and Hg 0.13 mg kg-1. Also, these soil parameters reduced in values in the sub-soil. The mean concentrations of heavy metals (Fe, Zn, Pb and Hg) in maize plants were significantly (P < 0.05) higher while N and P were significantly (P < 0.05) lower in those from the experimental sites within the vicinity of automobile workshops than in the control. Higher accumulation of these heavy metals was obtained in soil and shoots of maize from older workshops than in the younger ones. The study therefore concluded that edible crops, particularly the phytoplants should not be cultivated on polluted soils as this may pose a threat to human health, if the heavy metals enter the food chain.Keywords: Backyard farming, automobile, spent engine oil, carcass of vehicle, plant uptake, phytoplant.