GEOSPATIAL DISTRIBUTION AND MAPPING OF HYDROCARBON-CONTAMINATED SITES IN SELECTED COMMUNITIES OF THE NIGER DELTA, NIGERIA

Hydrocarbon contamination from anthropogenic activities remains a major environmental challenge in the Niger Delta. Accurate geospatial mapping of contaminant plumes is required for targeted remediation. To assess the geospatial distribution and lateral extent of hydrocarbon-impacted soils in two selected communities. Auger hole sampling was conducted at seven locations (AH1-AH7) plus a control (C) in Ajeokpori (Study Area 1) and Aabue-Korokoro Well 003 (Study Area 2). Coordinates were acquired with GPS in a projected metric system. Hydrocarbon impact was classified empirically as Low (<1000 mg/kg TPH), Medium (1000-5000 mg/kg TPH) and High (>5000 mg/kg TPH) in line with EGASPIN. Plume lateral extent was interpreted from Electrical Resistivity Tomography (ERT) profiles. In Study Area 1 (Ajeokpori), plume extents ranged from 68 m to 157 m. Five locations (AH1, AH2, AH3, AH4, AH6) were medium-impact (150-157 m) while two (AH5 - 68 m, AH7 - 144 m) were high-impact. AH5 and AH7 cluster within ∼111 m along a N-S alignment south of AH1-AH4. In Study Area 2 (Aabue-Korokoro), extents ranged from 35 m to 135 m (mean 96.4 m). Four locations (AH1-AH4) were low-impact, two (AH5-115 m, AH6-105 m) medium-impact, and one (AH7-80 m) high-impact. Medium-impact points AH5 and AH6 form a 12.2 m cluster in the southwest, while AH7 represents the southernmost hotspot. The study demonstrates that lateral extent does not equate to impact severity. Contamination is spatially heterogeneous. High-impact hotspots require targeted remediation, while extensive low and medium-impact plumes require boundary delineation. The geospatial framework provides a basis for ERT verification and monitoring.