Evaluation of Heavy Metal Contamination of Soils alongside Awka- Enugu Road, Southeastern Nigeria

Abstract

Fourteen top soil samples were collected from old Awka-Enugu road passing through Obioma, Nsude, Ngwo and Abor communities. Samples were taken from a depth of 10-15cm after making a hole with a pick axe. Total concentrations of cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), cobalt (Co), and chromium (Cr) were determined using a Buck 210 VGP atomic absorption spectrophotometer (AAS).Soil contamination was evaluated with pollution index (Pi) and index of enrichment factor (EF) concept. The enrichment factor of copper (Cu) was observed to be generally low across the study area. This implies that Cu toxicity in the area is not significant. However, the enrichment and pollution indices of cadmium (Cd) and lead (Pb) were observed to be high within the study area.The study area was observed to be highly contaminated by cadmium and lead but moderately contaminated with respect to nickel, zinc and chromium. The enrichment and pollution trends of the metals in descending order shows Cd > Pb > Ni > Zn > Cu > Cr > Co. In summary, the total heavy metal concentrations of soils studied were slightly higher than previously reported levels for similar soils which suggest some degree of heavy metal pollution.