Heavy Metal Concentration in Fields Used as Urban Waste Dump Site in Owerri, Imo State, South-Eastern Nigeria

The concentration of heavy metals in fields used as urban waste dump sites in Owerri, Imo state Nigeria was evaluated. Three dumpsites were selected from Avu (along Port Harcourt Road), Mechanic village (opposite Tipper Park) and Egbeada housing (along Onitsha Road). Site selection was based on the presence of the dumps for at least 10 years. Soil samples were collected from the dumpsites and 100 m away from the dumpsite as control, using soil auger at depth of 0 ‒15 cm and 15‒30 cm. Cassava crops were planted on all the sites and the cassava roots were sampled alongside the soil for the study of heavy metal contents in plant roots. Routine soil analysis and plant root analysis were carried out to determine the physio-chemical characteristics and heavy metal contents of the soil and plant roots. Results showed that heavy metal contents of soils and plants are significantly (p = 0.05) higher in the dumpsites than the control except for Cd which did not show significant difference. Also results showed that Cd and Pb content of soil and plants are higher (4.17 and 3.17 mg/kg, respectively) for soil and (0.2 and 0.1 mg/kg, respectively) for plant roots. It is therefore recommended that farmers should avoid growing crops in urban waste dumpsites to avoid food contamination and health hazard.