Distribution, source and historical trend of aliphatic hydrocarbons in sediment cores from Imo River, Southeast Nigeria

9^th World Convention on Recycling and Waste Management

October 22-23, 2018 Osaka, Japan

Inyang O Oyo-Ita, O E Oyo-Ita, U S Ugim and U U Umoh

University of Calabar, Nigeria
Tongji University, China

Posters & Accepted Abstracts: J Environ Anal Toxicol

Abstract :

Four recent sediment cores (0-30 cm long) from Afam (AF), Mangrove (MG), Estuary (ES) and illegal Petroleum refinery (PT) sites of the Imo River, Southeastern Nigeria were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) in order to characterize the sources, distribution and fate of aliphatic hydrocarbons as well as examine their historical trends of deposition and assess humans-induced changes in the last ca. 5 decades. Evaluation of proxy parameters such as Carbon Preference Indices (CPIs, 2.01-2.19), carbon maxima (Cmax 29, 31) and atomic Carbon-Nitrogen (C/N, 16.51-31.32) for the most recent top layers (0-5 cm) revealed greater wash-in of land-derived Organic Matter (OM), attributable to the recent rise in water height/flood following intense rainfall occasioned by global climate change. The bottom layer (PT1, 25-30 cm,) of the PT core deposited ca. 1964-1972 exhibited CPI of 0.97 and pristine/phytane (Pr/Ph, 3.75), suggesting that oil bunkering/ illegal refinery activity had begun in the region about 8 years after the first commercial discovery of oil in Nigeria in 1956. The non-detection of petroleum biomarkers (e.g. αβ-hopames) in the bottom layer (MG1, 25-30 cm; 1964-1972) of MG core revealed a period of relatively pristine depositional environment and the occurrence in high abundance of heptadecane (C17) in the middle layer (ES4, 10-15 cm, ca. 1981-1989) of ES core corresponded with the period of eutrophication that blocked the waterway in the area. Measurement of a marked Unresolved Complex Mixture (UCM) at the near-top layer (AF5, 5-10 cm) of AF core indicated that heaviest contamination by petroleum hydrocarbons occurred at ca. 1997-2005. This time-frame coincided with the period of intensive bunkering and oil pipeline vandalization by Niger Delta militant groups who campaign for fair allocation of oil revenue in the oil-rich region.

Biography :

E-mail: inyangoyoita@yaghoo.com