Composition and distribution of polynuclear aromatic hydrocarbons contamination in surficial coastal sediments from Odidi Area of Delta State, Nigeria

Abstract

The distribution of PAHs in the environment has become widespread due to the impacts of human activities especially those relating to oil exploration and exploitation. This study was carried out to determine the composition and distribution of PAHs in sediments from Odidi River, Delta State, Nigeria. Samples were collected from two (2) upstream and downstream sampling points each at depths of 0 - 15cm from March 2015 to August 2016. Gas chromatography-mass spectrometry was used to determine the poly nuclei aromatic hydrocarbons (PAHs) concentrations in the samples. All data analyses were done using Microsoft Excel 2016. The results obtained showed that the mean concentrations of PAHs ranged from 4.37±1.29μg/g to 23.13±1.42μg/g (upstream), and from 2.22±1.11μg/g to 25.00±2.63μg/g (downstream). There was no significant difference between the values obtained upstream and downstream. Across the 18 months of the study, only Florene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benzo(a)anthracene and Crysene were detected in every month. The composition of PAHs shows a higher concentration of Heavy PAHs (HPAHs) with the mix of Light PAHs (LPAHs) indicating that they were released by both petrogenic and pyrogenic sources in the study area. The PAHs content of the sediments exceeds the threshold effect concentration (TEC) TEC and the threshold effect levels TEL limits PAHs in sediments indicating potential environmental and health threats.