HEAVY METALS CONTAMINATION OF SOLID WASTE DISPOSAL SITES IN UMUAHIA, ABIA STATE

Abstract

The extent of soil contamination with heavy metals within the vicinity of four solid waste disposal sites in Umuahia were assessed. Four solid waste disposal sites were sampled at depth profiles of 0-10 cm, 10-20 cm and 20-30cm respectively. The soil samples were digested and subjected to heavy metal analysis using Atomic Absorption Spectrophotometer (AAS). The results obtained revealed a wide variation in the concentrations of different heavy metals at various sampling sites. The heavy metal concentrations of soil samples at solid waste disposal sites were higher than those obtained from the control site. Maximum concentrations of Pb, Hg, Cu, Zn, Cd and As, were 2.910.02 mg/l, 0.300.00 mg/l, 15.000.02 mg/l, 143.00.15 mg/l, 2.260.31 mg/l, and 0.050.00 mg/l respectively which were obtained from soils with depth profile 0 -10 cm. There was a depth- wise steady decrease in heavy metal concentrations in the soil samples analyzed. However, geo-accumulation (Igeo) index suggested significant contribution of cadmium to soil contamination. Geo-accumulation (Igeo) index of Cd ranged from 1.78 to 4.20, indicating very high contamination of the soil by Cd. But calculated pollution load index (PLI) ranged from 0.10 to 0.45, which does not indicate high pollution load status of the soil.