Assessment of Total Petroleum Hydrocarbon (TPH) Contaminated Site Using Soil Samples and Monitoring Wells

Abstract

This research focuses on assessing and remediating petroleum hydrocarbon contamination at Ogale, Eleme LGA, Rivers State. Soil and groundwater samples were collected and analyzed for Total Petroleum Hydrocarbon (TPH) using Gas Chromatography-Flame Ionization Detection (GC-FID). Results showed heavy contamination in both soil (up to 3,658 mg/kg) and groundwater (up to 149,726 ?g/L), exceeding the National Oil Spill Detection and Response Agency (NOSDRA) target levels of 1,000 mg/kg for soil and 600 ?g/L for groundwater. Soil contamination reached depths of up to 5 meters, particularly at sampling locations AH2, AH3, AH5, AH6, and AH9. Groundwater contamination was also significant in monitoring wells BH2, BH3, BH4, BH7 (light TPH), BH1, BH5, BH6, BH8, BH9 (moderate TPH), and BH10 (heavy TPH). Though petroleum hydrocarbons are biodegradable under aerobic conditions, natural biodegradation is slow due to limitations in nutrients, oxygen, and bioavailability. Therefore, a combined remediation strategy is proposed: Ex-situ Bioremediation for highly contaminated soils (excavation and treatment) In- situ Chemical Oxidation (ISCO) for groundwater and saturated soils within identified zones (ISCO- 1 to ISCO-6) This dual approach aims to restore the site to meet NOSDRA's regulatory standards, ensuring the land and water are fit for use with minimal environmental impact.

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