Baseline Assessment Of Biomarkers For Crude Oil Pollutants: Dna Adducts In Fish And Polycyclic Aromatic Hydrocarbons In Some Environmental Samples In The Western Coast Of Ghana

ABSTRACT

The industrialization of our society, including drilling for oil, mining of coal and minerals has led to increasing production of xenobiotic and natural chemical substances. Continual releases of polycyclic aromatic hydrocarbons (PAHs) from mining and drilling activities leads to their deposition in coastal environments and ultimately bioaccumulation in plants and animals, creating the danger of toxicity. PAH are deemed to be carcinogenic, mutagenic and teratogenic. In Ghana, oil drilling is ongoing at the Jubilee oil fields in the Western region, however, onshore baseline environmental assessment of pollutants such as PAHs have not yet been performed.

In this study, an environmental assessment of some communities bordering the oil drilling fields was performed to establish (1) levels of fish DNA adduct formation of fishes, (2) levels of polycyclic aromatic hydrocarbons in soil, plants, water and fishes. Examination of blood smears of several fish species showed the presence of micronuclei in fish from three of the study areas although their mean micronucleated frequencies were low and below the threshold frequency of 15%. There was no statistical difference between their mean frequencies upon one way ANOVA analysis with a p value < 0.05 except the mean of the fish Chloroscombrus chrysurus which showed a significant difference. Reverse phase HPLC analysis of fish, water, plant and soil samples collected from six study sites were done. Only two fish species Pomadasys incises at Aboadze and Thunnus alalunga from Dixcove recorded four and one PAH compounds respectively with concentrations above the maximum contaminant levels of 30 μg/Kg set by the

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USEPA. Mean concentration of PAHs in water samples were in the concentration range 1.4 to 1255 μg/L in water samples from two of the four study areas where water was found. All samples recorded concentrations above the threshold limit value of 50 ng/L set by the World Health Organization. Sixty plant samples were collected across the six study areas and only Erythrina senegalensis and Ficus umbellata recorded the presence of PAHs with concentrations in the range of 0.15-4.70 mg/Kg. Soil samples were collected from depths of 0-15 cm and 15-30 cm. The mean concentration of PAHs in surface soils (0-15cm) ranged from 0.1 to 95 mg/Kg with that at 15-30 cm ranging from 0.12 to 105 mg/Kg. The PAH composition profile in all the samples were similar with 2–3 ring PAHs being dominant which is suggestive of petrogenic source.