Pollution Indices, Potential Ecological Risks and Spatial distribution of Heavy Metals in soils around Delta State, Nigeria

Abstract

The study investigated the pollution indices and potential ecological risks of heavy metals (HM) occurrence in the soil affected by municipal waste from selected parts of Delta state southern, Nigeria. The heavy metal concentrations were analyzed using Atomic Absorption Spectrometry (AAS). Heavy metals analyzed for this study are Zn, Cr, Cu, Pb, Cd, Co, Ni, and As. Findings obtained from a heavy metal risk assessment indices such as potential ecological risk assessment (ERI), index of geoaccumulation (Igeo), degree of contamination (Cdeg), and Nemerow Pollution (PNI) showed that human activities such as automobile mechanics, dumping of solid waste, and agricultural activities are the major source of heavy metals pollutionin soil within the study area. Findings obtained from Igeo are contrary to findings obtained from ERI which revealed soil samples were unpolluted, implying that the anthropogenic activities within the area had little influence on the ERI. Observation from Cdeg indicated a low contamination degree in the soil. Results from PNI showed that 36.4 %, 27.3 %, and 13.6% of analyzed soil samples were classified to be clean, slightly clean, and moderately polluted respectively. Deduction from Principal Component Analysis PCA analysis and Pearson correlation matrix suggested that anthropogenic activities within the study area have led to the occurrence of heavy metals in soil.