Application of polynuclear aromatic hydrocarbons in chemical fingerprinting: the Niger Delta case study

ABSTRACT

Chemical fingerprinting is an aspect of environmental forensic investigation which involves chemical analysis of contaminants and associated chemicals to provide source specific information. Polynuclear Aromatic Hydrocarbons [PAHs] in the environment have 3 categories of sources namely petrogenic, pyrogenic and biogenic sources. Petrogenic PAHs are generated from geochemical alterations of organic mater. Pyrogenic PAHs originate when organic matter is incompletely combusted. Biogenic PAHs originate as a result of oxidation of microbial or plant derived compounds in older and deeper sediments. PAHs fingerprinting involves the determination of a number of quantitative diagnostic ratios of source specific marker PAH compounds. These quantitative diagnostic ratios may be used to distinguish petrogenic PAHs including phenanthrene/anthracene; benz[a]anthracene/chrysene; flouranthene/pyrene; phenanthrene/[phenanthrene+anthracene] and indeno[1,2,3-cd] pyrene/indeno [1,2,3-cd] pyrene + benzo [ghi] perylene from other sources. In this research over 40 environmental samples from the Niger Delta region were subjected to chemical fingerprinting employing some of the quantitative diagnostic ratios above with the aim of ascertaining the precise nature and source the contaminants. It was found that the PAHs contamination in the Niger Delta is not only emanating from petrogenic sources but other sources contribute significantly