Concentrations of heavy metals in soil and water receiving used engine oil in Port Harcourt, Nigeria

The concentrations of heavy metals (Cu, Ni, Pb, Zn) in soils and water receiving used engine oil were investigated. Soil and water samples were collected at discharge and control points at each study site. The heavy metals were analyzed using atomic absorption spectrophotometer. The results show that about 80% of used engine oil was disposed of directly into the environment and 20% was recycled via use in civil works. The concentrations of metals in test soil and water samples exceeded permissible limits. The concentrations of heavy metals ranged from 20 µg/g (Ni) to 493 µg/g (Pb) in soil and 0.019 mg/l (Ni) to 0.147 mg/l (Pb) in water. It was suggested that curbside collection and re-refining of used engine oil should be encouraged and appropriate legislation should also be put in place to prevent widespread pollution of the environment by these metal ions