Mapping soil susceptibility to crude oil pollution in the region of Delta, South-South Nigeria: A proportional study of environmetrics, health, ecological risks, and geospatial evaluation

Abstract

Today, the threat of crude oil pollution globally, has been a resounding epoch of ecosystem degradation. This affects the lives of flora and fauna in the ecosystem as well as influence the human's economic needs. The aim of this study is to assess the heavy metals and petroleum hydrocarbons concentrations (crude oil pollutants) in agricultural soils of selected communities in Niger-Delta region. Models were used to assess the crude oil pollution loads and its source apportionment. The results from the principal components analysis (PCA) for the heavy metals (HMs) and total petroleum hydrocarbons (TPHs) in soils showed high loading factors > 0.32. The source allotment were both of crustal and human origin. The cluster analysis for the physical and chemical parameters of the HMs and TPHs showed that stations 1, 5, 2, 4, 6 and 7 and 2, 6, 7 and 9 were similar respectively. The outcome of the ecological risk status of the sampled soils, showed that the metals in the nine sampling stations were at the slight risk level with Cd being the main donor. The results of the health risk for both non-carcinogenic and carcinogenic pathways for the metals were <1 respectively, indicating no human health risk. The results obtained from the kriging contour mapping of the HMs in the sampled stations, indicated mean variability across the stations with Zn and Pb having the highest values. This might be linked to the high concentration from the crude oil impact on the soil that might possibly elicit ecological and health risks (non-carcinogenic and carcinogenic) when ingested by plants and humans. We recommend steady assessment and monitoring of the soils in order to provide reference point data and information for proper justification and management alternatives.