Assessment of polynuclear aromatic hydrocarbon content in four species of fish in the Niger Delta by gas chromatography/mass spectrometry

Analysis for the presence of sixteen priority polynuclear aromatic hydrocarbons (PAHs) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene,  benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, dibenz[a, h]anthracene and indeno[1,2,3-cd]pyrene) was carried out on four different species of fish found in the Niger Delta region of Nigeria. The fish species included Parachanna obscura, Pseudolithus elongatus, Liza dumerillii and Clarais gariepinnus. Individual PAHs were identified through both retention time match with authentic standards and simultaneous maximization of several major ions from gas chromatography/mass spectrometry (GC/MS) data. Four isotopically-labeled internal standards namely D10-acenaphtalene, D12-chrysene, D10-phenanthrene and D12-perylene, were used for quantitation. All four species of fish were found to contain high levels of PAHs ranging from 0.41 to 39.64 ug/kg. The high molecular weight PAHs such as benzo[ghi]perylene, dibenzo[a,h]anthracene and indeno[1,2,3-cd]pyrene were consistently present in much higher amount than other PAHs in all four species of fish studied, suggesting higher resistance of these compounds to degradation.