Content area
Full text
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.
Key words: Crude oil; Fingerprinting; PAHs; Niger Delta
(ProQuest: ... denotes formula omitted.)
INTRODUCTION
Polynuclear Aromatic Hydrocarbons (PAHs) are a class of diverse organic compounds containing two or more fused aromatic rings of carbon and hydrogen atoms. They are ubiquitous environmental contaminants found in air, water and soil (Yang et al., 1991; Kennicutt et al., 1994; DuoAbul et al., 1997; Dejmek et al., 2001; Anyakora et al., 2005) and are always found as a mixture of individual compounds. PAHs comprise the largest class of chemical compounds known to be cancer-causing agents. Some, while not carcinogenic, may act as synergists (Anyakora et al., 2008). Owing to their low solubility and high affinity for particulate matter, PAHs are not usually found in water in notable concentrations; hence their presence in surface water or groundwater is an indication of a source of pollution.
PAHs are very difficult to degrade; the difficulty is due to the complexity and stability of their molecular structures (Yun and Xinhong, 2003; Arbabi et al., 2004; Nasseri et al., 2010). They are classified among the Semi-Volatile Organic Compounds (SVOC) having boiling points greater than 200°C. There...