Department of Plant Sciences

The study examined the concentration of heavy metals (Ni, Zn, Cu, Pb and Cd) in the sewage sludge dump soil and Cassava tuber harvested from cassava plant grown by farmers on the sewage sludge dump site along Owerri-Onitsha road Imo state, Nigeria, a dump site that was subjected to severe and intense sewage sludge dumping for about 2 years, abandoned for about 3 years and then cultivated with cassava plant. Soil and Cassava tubers were sampled and analysed using Atomic Adsorption Spectrophotometer. Concentration of the metals both in the soil and plant were found to be in excess but all, were not within critical concentration range except for Ni and Cu with concentrations within soil critical range (20-70, 50-250 mg kg-1 respectively). In all cases, the concentration were not above the established maximum tolerable limits. Thus, Ni , Zn ,Cu, Pb, and Cd concentrations in the soil were 25.15, 59.7, 68.2, 10.85, and 8.38 mg kg-1 respectively. For cassava plant, heavy metal concentration were 38.25, 138.7, 125.8, 5.50 and 3.60 mg kg-1 respectively. The concentrations were consistent with the findings of previous studies of sewage sludge contaminated soils .