Assessment of the Impacts of Artisanal Refinery of Crude Oil On Surface Water, Ground Water And Sediment Quality At Obi-Ayagha Community In Delta State Nigeria

Abstract

<p style="text-align: justify;"><strong>Aim: </strong>This study aims to assess the impacts of artisanal refinery activities on the quality of surface water, ground water, sediment and microbial density of the recipient environment at the abandoned artisanal refinery site in Obi-Ayagha community, Ughelli South, Delta State.</p> <p style="text-align: justify;"><strong>Place and Duration of Study: </strong>Abandoned artisanal refinery hydrocarbon impacted site, Obi-Ayagha, Ughelli South, Delta State, Nigeria. During was from September 2021- February 2022.</p> <p style="text-align: justify;"><strong>Methodology: </strong><strong>F</strong>ield sampling techniques were consistent with established and standards methodologies, Environmental Guidelines and Standards for Petroleum Industries in Nigeria (EGASPIN) and Federal Ministry of Environment (FMENV) procedural guidelines. Composite surface water samples were collected using a water sampler, ground water was collected using a water pump from drilled boreholes in the study site. Sediment sample was collected using Eckman dredge (grab) from the surrounding river around the study site. Physicochemical, microbial and metal parameters were analysed in the collected samples and controls, using standard methods to assess the impact of hydrocarbon contaminant from the artisanal refinery activities on the recipient environment.</p> <p style="text-align: justify;"><strong>Results: </strong> The study revealed that there was a significant  difference in Biochemical Oxygen Demand (BOD₅) values for the three borehole water sampled, with a mean value of 5.23± 3.0 mg/l and the control borehole site (3.00 ± 2mg/l). Total Petroleum Hydrocarbon results were below the instrument detection limit for the surface and ground water samples, while it recorded 5.38mg/kg for the sediment sample. Polyaromatic hydrocarbon results for all samples analysed were below the instrument detection  limit of <0.0001mg/kg. Total heterotrophic Bacteria counts obtained were between 2.08 -2.13 x 10³ CFU/ml, 1.13 - 1.26 x 10³CFU/ml and 2.36 x 10⁵CFU/g for  surface water, groundwater and sediment samples respectively. Values obtained for all metals analysed in the study samples were within regulatory stipulated limits. Iron metal, though does not have available limits for sediment samples, recorded the highest concentration of 5585 ± 2.12 mg/kg in relation to other metals.</p> <p style="text-align: justify;"><strong>Conclusion:</strong>Results obtained from the environmental samples analysed showed the parameters assessed were within regulatory limits. This could have been due to natural attenuation(remediation) of the environment giving the prolonged period of abandonment of the artisanal refining activities<strong>.</strong></p> <p style="text-align: justify;">The integration of artisanal and modular refinery operations into the oil and gas sector will curtail illegal oil activities in the Niger Delta regions and will also promote the availability of petroleum products, stabilize prices, eliminate shipping costs and provide employment opportunities for the inhabitants in the region and Nigeria in general.  It is further recommended that with enough artisanal and modular refineries being granted license by the Federal Government in the country, Nigeria should be able to conserve foreign exchange currently utilized for the importation of petroleum products and promote socio-economic development.</p>