Geochemical Assessment of Hydrocarbon Contaminated Site in Central Niger Delta, Nigeria

Abstract

Hydrocarbon contamination results in environmental degradation and adversely affects health and socioeconomic standards of life globally and the Niger Delta in particular. This study assessed soil pollution and contamination levels of a Total Petroleum Hydrocarbon (TPH) impacted site at Otuasega in Ogbia Local Government Area of Bayelsa State, Nigeria. Geochemical analysis of soil samples for TPH was performed using gas chromatography (flame ionization detection) (GC-FID) and TPH divided into different carbon fractions in terms of the aliphatic and aromatic compounds and also according to their equivalent carbon number (EC). Soil type, particle size and size distribution were obtained by sieve analysis. Results showed that the soil type is generally composed of sand/clayey sand at proportions of 16-32 % fines and 68-84% sand to depth of over 30 cm. Chromatograms indicate predominance of the C15-C21 carbon fractions, the soils TPH concentrations generally increase with depth, having a minimum of 17,457.00 ppm at 0 – 15 cm and a maximum of 163,609.50 ppm at 15 cm - 30 cm. These concentrations are enormously higher than the target value of 50 ppm for Department of Petroleum Resources, (DPR) and intervention values of 300 ppm for Shell Petroleum Development Company, (SPDC) and 500 ppm for Environmental Guidelines and Standards for Petroleum Industry in Nigeria, (EGASPIN 2002) for TPH in soils of Niger Delta. A collective cooperation by respective authorities is paramount to achieve a sustainable management of oil pollution in the area.