The Niger Delta is one of the major hydrocarbon provinces of the world, with an estimated reserve of about 23 billion barrels of oil and 183 trillion cubic feet of natural gas with ongoing exploration in the province for over 50 years [1]. Much of the oil industries located within this region have contributed immensely to the growth and development of the nation.
However, oil exploration activities have rendered the Niger Delta region one of the most severely degraded ecosystems in the world [2]. Crude oil spills are common in the region with an estimated total of over 7,000 oil spill accidents reported over 50 years [3]. Studies have shown that the quantity of oil spilt over this period amounts to 9–13 million barrels, which is equivalent to 50 Exxon Valdez spills [4].
These spills occur through equipment failure, operational mishap, haulage, oil bunkering and/or vandalisation of pipelines leading to the destruction of aquatic and terrestrial flora and fauna of the Niger Delta region [5].
Geochemical or Oil fingerprinting is one of the ways of assessing and evaluating petroleum pollution. It involves the analysis of the released oil with gas chromatography (GC) and measurement of the hydrocarbon compound contents [6]. From the qualitative method (visual comparison of chromatograms) as well as quantitative determination of polycyclic aromatic hydrocarbons (PAHs) diagnostic ratio,
The study area lies within the Niger Delta region between latitudes 5°37′00″E–5°47′00″E and longitudes 5°53′00″N–6°02′30″N (Figure 1) and cuts across Sapele and Ethiope West Local government, Delta State, Nigeria. Stratigraphically, the Niger Delta consists of three formations, notably; Akata Formation, which is the oldest unit and constitutes under compacted shales, turbidites and silts. This is overlain by the paralic Agbada Formation, made up of alternating sequences of sandstone and shale which contains most of the hydrocarbon reservoirs in the basin while the youngest unit is the Benin Formation, which is made up of continental sands [7]. The area is characterised by an even topography. It is situated in the tropics and experiences a fluctuating climate characterised by rainy and dry seasons. The area is drained by minor rivers which are tributaries of the major River Ethiope with a dendritic pattern.
The field study involved the collection of soil and water samples from selected points as shown in Figure 2. A total of sixteen samples made up of ten crude oil-impacted soils taken at a depth of 30 cm and six water samples (two from boreholes, two from burrow pits plus and two from surface water – one from a river and the other from rain harvest as control) were collected. The water and soil samples were collected in clean, well-labelled glass jars and aluminium foils, respectively, and taken to the laboratory for analyses. Due to the relatively high volatility and instability of AHs and PAHs, the soils were not prepared using conventional soil preparation techniques such as grinding and sieving. However, the soil samples were dried by mixing the samples with 5 g of anhydrous sodium sulfate.
Organic pollutants were separated from the soil and water samples using an ultrasonic extraction and a separatory funnel, respectively. The extracts were fractionated into the AH and PAH fractions by eluting with
The results of the AH and PAHs in this study are shown in Table 1. The concentrations of the AHs and PAHs found in the studied samples are low when compared with values from other areas in the Niger Delta (Table 2). However, in this study, the concentrations are higher than the regulatory limits given by the United Nations Environment Programme (UNEP) [9].
Css_1 | Soil | 37.59 mg/kg | 16.88 mg/kg |
Css_2 | Soil | 25.70 mg/kg | 11.66 mg/kg |
Css_3 | Soil | 34.43 mg/kg | 14.72 mg/kg |
Css_4 | Soil | 22.52 mg/kg | 14.77 mg/kg |
Css_5 | Soil | 929.44 mg/kg | 14.54 mg/kg |
Css_6 | Soil | 79.55 mg/kg | 15.91 mg/kg |
Css_7 | Soil | 36.85 mg/kg | 13.11 mg/kg |
Css_8 | Soil | 34.86 mg/kg | 10.54 mg/kg |
Css_9 | Soil | 44.73 mg/kg | 12.15 mg/kg |
Css_10 | Soil | 41.93 mg/kg | 15.81 mg/kg |
Cbw_1 | Water | 0.22 mg/l | 0.09 mg/l |
Cbw_2 | Water | 0.13 mg/l | 0.29 mg/l |
Pw_1 | Water | 5.78 mg/l | 0.86 mg/l |
Pw_2 | Water | 5.14 mg/l | 1.11 mg/l |
Sw_1 | Water (control) | 0.61 mg/l | 0.17 mg/l |
Sw_2 | Water | 2.08 mg/l | 0.86 mg/l |
AH, aliphatic hydrocarbon; PAHs, polycyclic aromatic hydrocarbons.
Contaminated soil | 22.52–929.44 | 10.54–16.88 | |
Olawoyin et al. [14] | 7,878.8–76,510.9 | 31.4–132.0 | |
Adedosu et al. [12] | 575.96–1,202.47 | 7.40–78.30 | |
Udoetok and Osuji Leo [24] | 77.64–3,946.58 | 8.16–3,756.81 | |
United Nations Environment Programme (UNEP) [9] | 10 | No limit | |
Department of Petroleum Resources (DPR) [15] | No limit | 1.00 | |
United States Environmental Protection Agency (USEPA) [10] | No limit | 1.00 | |
Borehole | 0.13–0.22 | 0.09–0.29 | |
Olawoyin et al. [14] | No limit | 119.90–450.58 | |
Ibezue et al. [29] | 0.03–0.422 | 0.002–0.007 | |
WHO | 0.0002 | 0.0002 | |
Department of Petroleum Resources (DPR) [15] | No limit | 0.1 | |
Surface water | 0.61–2.08 | 0.17–0.86 | |
Inyang et al. [30] | 2.5–183.0 | No limit | |
European Union Environmental Protection Agency (EUEPA) [25] | 0.3 | No limit | |
Department of Petroleum Resources (DPR) [15] | No limit | 0.0001 | |
WHO | No limit | 0.05 | |
Contaminated water | 5.14–5.78 | 0.86–1.11 | |
Inyang et al. [30] | 2.5–183.0 | No limit | |
European Union Environmental Protection Agency (EUEPA) [25] | 0.3 | No limit | |
WHO | No limit | 0.05 |
AH, aliphatic hydrocarbon; PAH, polycyclic aromatic hydrocarbon.
The distribution of seventeen priority PAHs in the water and soil samples in the study area is presented in Table 3. The main PAH pollutants in the studied areas were found to be Chrysene, Acenaphthene, Methylnaphthalene, Naphthalene, Anthracene, Benzo(g,h,i) perylene, Fluorene, Indeno(1,2,3-cd)perylene and Phenanthrene. It is important to note that the sum of the PAHs in the contaminated soil samples is 10.54–16.89 times higher than the standard level (1 mg/kg) of heavy [10]. The level of PAH pollution in the control sample (Sw-1) is very low as compared with those from the other samples studied. The spatial distribution of PAHs in this study is shown in Figure 3 and indicates a predominance of three-ring PAHs which suggests recent deposition according to Jiao et al. [11]. The abundance of three-ring PAHs in the study area is in agreement with studies of some oil-polluted sites in the Niger Delta [12]. The four-ring PAHs are also abundant and they indicate the persistence of high molecular weight (HMW) PAHs in the environment. According to Li et al. [13], petrogenic sources are those PAHs derived from petroleum spills while pyrogenic sources are generated by incomplete combustion of fossil fuel such as coal, crude oil and natural gas plus biomass. Diagnostic ratios such as Phenanthrene/Anthracene, Fluorene/Pyrene, Benz(a)pyrene/Chrysene, Naphthalene/Acenaphthene, Anthracene/(Phenanthrene + Anthracene), Fluoranthene/(Fluoranthene + Pyrene), Benzo(a)anthracene/(Benzo(q)anthracene + Chrysene), Indeno(1,2,3-cd)perylene/(Indeno (1,2,3-cd)perylene + Benzo(g,h,i)perylene) and low molecular weight (LMW) hydrocarbon/HMW hydrocarbon have been utilised in deducing the source of pollution [18, 20, 23, 26, 28]. From the source diagnostic indices as presented in Table 4, most PAHs in the study area are from petrogenic sources with a minor contribution from pyrogenic sources.
Nap | BDL | 0.04 | 0.098 | 0.043 | BDL | 0.046 | 0.814 | 0.819 | 0.809 | 0.758 | 1.228 | 1.004 | 0.913 | 0.807 | 0.746 | 0.788 |
Mnap | BDL | BDL | 0.066 | 0.176 | BDL | 0.064 | 1.814 | 1.007 | 1.356 | 1.106 | 3.249 | 1.548 | 1.264 | 1.093 | 1.235 | 1.350 |
Acep | BDL | BDL | 0.056 | 0.037 | BDL | 0.066 | 3.352 | 1.148 | 1.666 | 0.683 | 1.459 | 2.311 | 1.672 | 1.340 | 1.740 | 1.830 |
Ace | BDL | 0.07 | 0.081 | 0.087 | BDL | 0.073 | 1.404 | 1.437 | 1.420 | 1.558 | 3.020 | 1.536 | 1.401 | 1.410 | 1.376 | 1.433 |
Fl | BDL | BDL | 0.036 | 0.173 | BDL | 0.042 | 0.768 | BDL | 0.697 | 1.216 | 1.085 | 0.959 | 0.706 | 0.697 | 0.769 | 0.771 |
Phe | BDL | 0.06 | 0.061 | 0.048 | BDL | 0.057 | 0.985 | 1.041 | 1.032 | 1.027 | 0.174 | 1.509 | 0.961 | 0.803 | 0.801 | 0.958 |
Ant | BDL | 0.01 | 0.010 | 0.133 | 0.166 | 0.017 | 0.364 | 0.274 | 0.375 | 0.744 | 0.111 | 1.632 | 0.336 | 0.222 | 0.233 | 0.265 |
Flu | BDL | 0.05 | 0.046 | 0.040 | BDL | 0.057 | 0.924 | 0.906 | 1.156 | 0.841 | 0.088 | 0.301 | 1.027 | 0.759 | 0.747 | 0.927 |
Pyr | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | 0.146 | 0.250 | BDL | BDL | BDL | BDL |
BaA | BDL | BDL | 0.133 | 0.050 | BDL | 0.015 | 0.299 | BDL | 0.313 | 0.707 | 0.259 | 0.134 | 0.292 | 0.124 | 0.104 | 0.269 |
Chr | 0.02 | 0.05 | 0.205 | 0.137 | BDL | 0.033 | 1.217 | 0.296 | 0.758 | 1.265 | 0.108 | 0.483 | 0.620 | 0.241 | 0.491 | 0.082 |
BbF | 0.02 | 0.01 | 0.010 | 0.042 | BDL | 0.105 | 1.592 | 0.728 | 0.506 | 2.668 | 0.085 | 0.447 | 0.501 | 0.108 | 1.149 | 0.066 |
BkF | 0.02 | 0.01 | 0.018 | 0.010 | BDL | 0.018 | 0.860 | 0.320 | 0.199 | 0.434 | 0.269 | 0.169 | 0.393 | 0.157 | 0.242 | 0.248 |
BaP | 0.02 | BDL | BDL | 0.025 | BDL | 0.015 | 0.252 | 0.215 | 0.883 | 0.228 | 0.091 | 0.366 | 0.167 | 0.413 | 0.203 | 0.283 |
DahA | BDL | BDL | 0.026 | 0.012 | BDL | 0.014 | 0.202 | 0.211 | 0.290 | 0.194 | 0.065 | 0.151 | 0.359 | 0.516 | 0.263 | 0.295 |
InP | 0.01 | BDL | BDL | 0.038 | BDL | 0.114 | 0.912 | 1.895 | 0.407 | 0.665 | 0.562 | 0.396 | 0.598 | 0.659 | 0.182 | 3.374 |
BghiP | BDL | BDL | BDL | 0.060 | BDL | 0.126 | 1.119 | 1.362 | 2.852 | 0.673 | 2.545 | 2.722 | 1.899 | 1.193 | 1.869 | 2.870 |
Total | 0.09 | 0.3 | 0.856 | 1.109 | 0.166 | 0.863 | 16.879 | 11.657 | 14.720 | 14.768 | 14.543 | 15.917 | 13.108 | 10.544 | 12.151 | 15.807 |
Mean | 0.005 | 0.02 | 0.050 | 0.065 | 0.010 | 0.051 | 0.993 | 0.688 | 0.866 | 0.869 | 0.855 | 0.936 | 0.771 | 0.620 | 0.715 | 0.930 |
Ace, Acenaphthene; Acep, Acenaphthylene; Ant, Anthracene; BaA, Benzo(a)anthracene; BaP, Benzo(a)pyrene; BbF Benzo(b)fluoranthene; BDL, Below Detection Limit; BghiP, Benzo (g, h, i) perylene; BkF, Benzo(k)fluoranthene; Chr, Chrysene; DahA, Dibenzo (a, h) anthrace; Fl, Fluorene; Flu, Fluoranthene; InP, Indeno (1, 2, 3-cd) perylene; Mnap, 2-Methylnaphthalene; Nap, Naphthalene; Phe, Phenanthrene; Pyr, Pyrene.
ΣLMW/ΣHMW | <1 | Pyrogenic | Zhang et al. [26] | 0–2.45 | Petrogenic/pyrogenic |
>1 | Petrogenic | ||||
Fl(Fl + Pyr) | <0.5 | Petroleum Emissions | Ravindra et al. [20] | 0–0.4 | Petroleum emissions |
>0.5 | Diesel Emissions | ||||
Ant(Phe + Ant) | <0.1 | Pyrogenic | Pies et al. [18] | 0–0.21 | Petrogenic/pyrogenic |
>0.1 | Petrogenic | ||||
Flu(Flu + Pyr) | <0.4 | Petrogenic Fossil fuel Combustion Grass, wood, coal combustion | De La Torre-Roche et al. [27] | 0–0.4 | Petrogenic/mixed source of fossil fuel and combustion |
0.4–0.5 | |||||
>0.5 | |||||
BaA/(BaA + Chr) | 0.2–0.35 | Coal combustion | Akyüz and Çabuk [23] | 0–0.31 | Coal combustion/petrogenic |
>0.35 | Vehicular emission | ||||
<0.2 | Petrogenic | Yunker et al. [28] | |||
>0.35 | Combustion | ||||
InP/(InP + BghiP) | <0.2 | Petrogenic | Yunker et al. [28] | 0–0.23 | Petrogenic/petroleum combustion |
0.2–0.5 | Petroleum Combustion | ||||
>0.5 | Grass, Wood, Coal Combustion |
ΣLMW/ΣHMW, the sum of low molecular weight hydrocarbon/the sum of high molecular weight hydrocarbon.
C8 | BDL | BDL | BDL | 0.11 | BDL | 0.51 | 12.76 | 1.13 | 0.59 | 0.30 | 2.38 | BDL | 1.32 | 1.44 | 1.77 | 9.42 |
C9 | BDL | BDL | 0.02 | 0.01 | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL |
C10 | BDL | BDL | 0.81 | 0.17 | BDL | 0.01 | BDL | BDL | BDL | BDL | 0.94 | BDL | BDL | BDL | 0.29 | 0.59 |
C11 | BDL | BDL | 0.08 | 0.04 | BDL | 0.04 | 1.63 | BDL | BDL | BDL | 11.06 | BDL | BDL | BDL | BDL | 0.53 |
C12 | BDL | BDL | 0.18 | 0.11 | BDL | BDL | BDL | BDL | BDL | BDL | 6.35 | BDL | BDL | 0.06 | BDL | 0.04 |
C13 | BDL | BDL | 0.23 | 0.18 | BDL | 0.14 | 2.43 | 0.36 | 0.46 | BDL | 11.24 | BDL | BDL | 0.18 | 1.28 | 3.06 |
C14 | BDL | 0.02 | 0.33 | 0.23 | 0.03 | 0.01 | 0.53 | 0.77 | 0.66 | 0.42 | 47.91 | 0.09 | BDL | 0.17 | 0.57 | 0.56 |
C15 | BDL | BDL | 0.31 | 0.23 | BDL | BDL | BDL | BDL | BDL | 0.06 | 48.04 | 0.88 | 0.13 | 0.29 | BDL | BDL |
C16 | BDL | 0.04 | 0.33 | 0.25 | 0.02 | 0.01 | 0.85 | 0.19 | 0.12 | 0.69 | 29.37 | 3.90 | 0.31 | 0.39 | 0.95 | 0.89 |
C17 | BDL | BDL | 0.31 | 0.25 | BDL | BDL | BDL | BDL | BDL | BDL | 9.39 | 6.82 | BDL | BDL | BDL | BDL |
C18 | BDL | 0.03 | 0.28 | 0.23 | 0.01 | 0.04 | 0.45 | 0.10 | 0.73 | 0.60 | 17.20 | 7.94 | 0.13 | BDL | 0.93 | 0.64 |
C19 | BDL | 0.01 | 0.21 | 0.20 | 0.02 | BDL | BDL | 0.27 | 0.22 | 0.13 | 16.14 | 7.08 | BDL | 0.19 | 0.14 | BDL |
C20 | BDL | 0.02 | 0.22 | 0.28 | 0.03 | 0.05 | 0.39 | 1.18 | 0.65 | 0.78 | 24.05 | 7.78 | 1.24 | 1.36 | 1.65 | 0.74 |
C21 | BDL | BDL | 0.20 | 0.19 | BDL | BDL | BDL | BDL | BDL | 0.12 | 15.49 | 6.19 | 0.04 | BDL | BDL | BDL |
C22 | BDL | BDL | 0.26 | 0.22 | 0.02 | 0.02 | 1.37 | 0.57 | 0.28 | BDL | 15.23 | 5.27 | 1.49 | 1.71 | 0.45 | 0.17 |
C23 | 0.01 | BDL | 0.26 | 0.17 | BDL | BDL | 0.13 | BDL | BDL | 0.24 | 11.69 | 4.35 | BDL | 0.42 | BDL | BDL |
C24 | 0.01 | 0.02 | 0.36 | 0.23 | 0.03 | BDL | BDL | BDL | 0.60 | 1.62 | 19.32 | 4.16 | 0.38 | 0.34 | BDL | 0.05 |
C25 | 0.02 | BDL | 0.30 | 0.17 | BDL | BDL | 0.40 | BDL | BDL | 0.19 | 13.90 | 3.17 | BDL | BDL | BDL | BDL |
C26 | 0.02 | BDL | 0.12 | 0.16 | BDL | 0.04 | 0.73 | 0.66 | 1.01 | 0.74 | 12.47 | 2.75 | 1.40 | 1.14 | 1.15 | 0.96 |
C27 | 0.02 | BDL | 0.14 | 0.14 | BDL | BDL | 0.59 | BDL | BDL | 0.31 | 10.58 | 2.44 | BDL | 0.19 | BDL | BDL |
C28 | 0.01 | BDL | 0.11 | 0.12 | BDL | 0.03 | 0.86 | 0.30 | 0.71 | 0.54 | 18.87 | 1.93 | 0.96 | 1.18 | 0.80 | 0.68 |
C29 | BDL | BDL | 0.08 | 0.10 | BDL | BDL | 0.24 | BDL | BDL | BDL | 30.88 | 1.19 | BDL | BDL | BDL | BDL |
C30 | BDL | BDL | 0.08 | 0.05 | BDL | BDL | BDL | BDL | BDL | BDL | 29.12 | 0.29 | BDL | BDL | BDL | BDL |
C31 | BDL | BDL | 0.08 | 0.08 | BDL | BDL | 1.06 | BDL | BDL | BDL | 15.14 | 1.11 | 0.63 | 0.32 | BDL | BDL |
C32 | BDL | BDL | BDL | BDL | BDL | 0.11 | BDL | 2.47 | 4.62 | 0.72 | 4.53 | BDL | BDL | 0.44 | 5.40 | 3.79 |
C33 | BDL | BDL | BDL | 0.31 | BDL | 0.40 | 5.05 | 8.38 | 12.62 | 2.20 | 13.12 | BDL | 3.23 | 4.24 | 13.73 | 10.84 |
C34 | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | 15.04 | 3.88 | 3.66 | BDL | BDL | BDL |
C35 | BDL | BDL | BDL | BDL | 0.07 | BDL | BDL | BDL | 11.16 | BDL | 6.12 | BDL | BDL | BDL | BDL | BDL |
C36 | 0.13 | BDL | BDL | 0.75 | 0.03 | 0.02 | 8.12 | 7.66 | BDL | 6.97 | 11.78 | BDL | 9.81 | 7.43 | 12.83 | 11.78 |
C37 | BDL | BDL | 0.15 | BDL | 0.26 | 0.65 | BDL | BDL | BDL | BDL | 5.90 | BDL | 9.99 | 11.26 | BDL | BDL |
C38 | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | 2.27 | BDL | BDL | BDL | BDL | BDL |
C39 | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL |
C40 | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL | BDL |
PRISTANE | BDL | BDL | 0.27 | 0.16 | BDL | BDL | BDL | BDL | BDL | 5.32 | 392.91 | 6.70 | BDL | BDL | BDL | BDL |
PHYTANE | BDL | BDL | 0.04 | 0.02 | 0.08 | BDL | BDL | 1.67 | BDL | 0.56 | 61.00 | 1.64 | 2.12 | 2.10 | BDL | BDL |
Pr/nC17 | 0 | 0 | 0.90 | 0.63 | 0 | 0 | 0 | 0 | 0 | 0 | 41.84 | 0.98 | 0 | 0 | 0 | 0 |
0.22 | 0.13 | 5.78 | 5.14 | 0.61 | 2.08 | 37.59 | 25.69 | 34.43 | 22.52 | 929.44 | 79.55 | 36.85 | 34.86 | 44.73 | 41.94 |
AH, aliphatic hydrocarbon.
Cbw_1 | 0.29 | 1.81 |
Cbw_2 | 0.06 | 0 |
Pw_1 | 0.76 | 0.82 |
Pw_2 | 0.71 | 0.79 |
Sw_1 | 2.14 | 0 |
Sw_2 | 1.47 | 0 |
Css_1 | 0.44 | 0.21 |
Css_2 | 0.60 | 0 |
Css_3 | 2.46 | 0 |
Css_4 | 0.24 | 0.27 |
Css_5 | 0.85 | 0.72 |
Css_6 | 0.87 | 0.94 |
Css_7 | 0.68 | 0.006 |
Css_8 | 1.09 | 0.31 |
Css_9 | 0.57 | 0 |
Css_10 | 0.48 | 0 |
Mean | 0.86 | 0.37 |
AH, aliphatic hydrocarbon.
Although some components of the PAHs and AHs in the study area have been degraded, the majority of the other components still persist in the environment which may affect groundwater, rivers and soils. This may be injurious to both human and animal health. Some sources of the PAH and AH studied are pyrolytic, i.e. from combustion/bush fire occasioned by explosion of oil tankers, oil installations, leakages from oil pipes and pipelines explosion during oil bunkering or pipeline vandalism. All these have bearing on agriculture, water supply settlement and the biodiversity within the study area.
PAHs are known to be injurious to health. The eight PAHs typically considered as possible carcinogens are Benzo(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Dibenzo(a,h)anthracene, Indeno(1,2,3-cd)pyrene and Benzo(g,h,i) perylene. In particular, Benzo(a)pyrene has been identified as being highly carcinogenic. The World Health Organization (1993) revealed that Benzo(a)pyrene concentration of 0.7 μg/l corresponds to an excess lifetime cancer risk of 10–5. The BaP-equivalent (BaPE) is used as a way to access carcinogenic risk due to the contamination by PAHs. The BaPE not only includes the risk due to BaP but also calculates all of the carcinogenic PAHs, where each of the PAH is weighed according to its carcinogenicity in relation to the carcinogenicity of BaP, which is measured by 1. This index can be calculated with this equation [17]; BaPE = BaP + (BaA*0.06) + (BkF*0.07) + (BbF*0.07) + (DahA*0.06) + (InP*0.08). BaPE ranged from 0 mg/l to 0.042 mg/l and 0.22 mg/kg to 1.16 mg/kg in the water and soil samples, respectively. The highest value of BaPE in the samples is in Css_3, hence indicating that PAHs at this sample point have high carcinogenic effects.
The prevalence of petrogenic-derived PAHs was confirmed in the studied samples. AHs in both media originated from both petrogenic and biogenic. The AHs are products from both terrestrial and marine inputs. The pollution level of the study area is high as compared with USEPA, DPR and WHO standards which poses health hazards. However, the values are lower compared with other areas in the Niger Delta. The PAH and AH diagnostic ratios have proven to be useful in tracking pollution emission sources and have helped in assessing the level of degradation of oils in impacted soils and water.