An integrated geochemical and geoelectrical Investigation of an ancient crude oil spill site in south east Port harcourt, Southern Nigeria

Abstract

Geochemical analysis of borehole soil samples for Total Petroleum Hydrocarbon (TPH), geoelectrical imaging and geotechnical sieve analysis were used to assess the intensity and extent of hydrocarbon contamination at an ancient oil spill site near Ejama-Ebubu community in Eleme, near Port Harcourt. The subsurface sequence is generally composed of sandy clay/clayey sand to depth of over 10 m. The clayey sand consists of 24-37% fines and 63-76% sand. Soils Total Petroleum Hydrocarbon (TPH) concentrations generally decrease from a maximum of 6428 ppm at 1 m at the time of investigation to a minimum of 1508 ppm at 5 m depth within the impacted zone. These values are much higher than the Department of Petroleum Resources (DPR) background value of 50 ppm for TPH in soils of the Niger Delta, thereby establishing high level of contamination.

Keywords: Geochemical Analysis, Geoelectric Imaging, Borehole Sampling, TPH Concentrations, Oil Spill, Contamination