Human Health Risk Assessment of Crude Oil Polluted Soil, Surface & Groundwater Sources in Emohua, Rivers State, Nigeria

This study was carried out to assess the human health risk associated with a crude oil spill site in Emohua Local Government Area of Rivers State, Niger Delta. The Total Content and Fraction’s approaches were adopted to assess the human health risk. Total Content approach was carried out by comparing the concentration of various contaminants in the environmental media studied with the Intervention Values prescribed while the Fractions approach was carried out using RBCA Toolkit for Chemical Releases version 2.6. The results indicate that concentration indices for Total Petroleum Hydrocarbon (TPH) and Polycyclic Aromatic Hydrocarbon (PAH) were greater than the acceptable limit of 1.0 for both the maximum and mean concentrations in soil and groundwater, indicating unacceptable risk at this site. The result from the Fraction’s approach showed that carcinogenic risks are identified for the site through the soil and grounwater exposure pathways as the Total Risk Values for soil (1.7 x10-3) and groundwater (5.6 x 10-1) are higher than the target risk of 1.0 x 10-5 while toxic effects risks are identified for all pathways in the site with Total Health Risk Index for all four pathways greater than the applicable limit of 1.0. Ingestion of groundwater for carcinogenic risk with risk value 5.6 x 10-1 and inhalation of indoor air for non-carcinogenic risk Health Risk Index of 1.0 x104 are identified as the major contributing exposure pathways at this study site. It was therefore concluded that the study site poses unacceptable risk to human health and needs immediate intervention.