GEOCHEMICAL BACKGROUND, BASELINE VALUES DETERMINATION AND SPATIAL DISTRIBUTION OF HEAVY METAL CONTAMINATION IN SOIL OF FIELD X, ONSHORE NIGER DELTA.

This study evaluates the geochemical contamination of soil in the area, a site influenced by oil and gas exploration in the soil of Field X Onshore Niger Delta. A combination of multivariate statistical tools including Principal Component Analysis (PCA), hierarchical clustering, and various contamination indices was employed to assess pollution levels and identify key contaminants. Correlation analysis revealed strong positive relationships between Total Organic Carbon (TOC) and Total Hydrocarbon Content (THC), indicating significant petroleum-related contamination. Heavy metals such as iron (Fe) and cadmium (Cd) also showed notable associations, suggesting additional industrial pollution sources. PCA reduced the dataset into three principal components (PCs), explaining about 70.19% of the total variance. PC1 (37.24%) was dominated by hydrocarbons (THC, TOC), PC2 (19.95%) reflected heavy metal influence (Zn, Ni, Cu), and PC3 (13.00%) captured pH and other soil geochemical parameters. A scree plot validated the selection of these three PCs. Hierarchical clustering grouped samples into three clusters: Cluster 1 (SS1, SS2, SS3 and SS5) with severe contamination, Cluster 2 (SS6, SS8 and SS9) with moderate levels, and Cluster 3 (SS4, SS7 and SS10) with minimal contamination. Contamination indices supported these findings. High contamination and enrichment factors were observed at SS1-10 and only Zinc had low contamination value, while geochemical index values confirmed no pollution in SS1-10. Pollution Load Index (PLI) and Contamination Degree (CD) further emphasized the urgent need for remediation in heavily impacted sites. This study demonstrates the effectiveness of multivariate techniques and indices in assessing environmental impacts and guiding targeted remediation strategies.