ABSTRACT. Carcinogenic potency of polycyclic aromatic hydrocarbons (PAHs) in soils obtained from seven different sampling locations in Effurun metropolis and its environs of Niger Delta Area of Nigeria were evaluated. The 16 US EPA priority PAHs were determined with GC-MS. The concentrations of individual PAHs observed were used to compute the carcinogenic risk potency of the PAHs relative to benzo(a)pyrene (reference carcinogen). Benzo(a)pyrene equivalent concentration in soils from industrial sites, possess about 22 times carcinogenic potencies than soils from residential areas.

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ABSTRACT. An investigative study on polycyclic aromatic hydrocarbons (PAHs) in soils of different sampling stations in Effurun metropolis and its environs of the Niger Delta Area of Nigeria was carried out with gas chromatography mass spectrometry (GC-MS). Among the 16 US EPA priority PAHs determined, pyrene was observed to be the most abundant compound at all sites (20 %), followed by fluoranthene (14 %), phenanthrene (12 %), chrysene (10 %) and benzo(ghi)perylene (6 %). High concentrations of pyrene could be attributed to anthropogenic source such as industrial and vehicular emissions. On the other hand, naphthalene, acenathalene and anthracene accounted for 3.2 %, 1.6 %, and 1.1 %, respectively. The observed trend: Refinery > Ekpan > Enerhen > Water Resources > Alegbo > Ugborikoko > Ugboroke could be attributed to the density of industrial and commercial activities in each area. Clear differences in the total PAH between urban/industrial and rural areas were observed. The results showed that PAH levels in soils from heavily industrial sites were higher in concentrations to the effect that Refinery locations were comparatively higher than all other locations. The higher levels of PAHs observed in the Refinery location are clear indications of combustion emissions and gas flaring from fractionating towers.