Impact of Oil Refinery Effluent on the Water Quality: Case Study of Ekerikana Creek in Nigeria
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Date
2013
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Abstract
Over the years Ekerikana creek in Okrika Local Government Area of Nigeria has served as the recipient water body where refinery effluents are discharged. The level of chemical contaminant in the treatment refinery waste water has always been a controversy. In the same way the level of impact of these discharges on the adjoining river has been a cause of worry to the community. A study was conducted on Ekerikana creek and its adjourning river to determine the impact of refinery effluent on the water quality. Standard methods were used to determine the physicochemical parameters of Refinery effluent and the effluent receiving river water bodies at four selected sites; Refinery effluent (S1), Point of Discharge (S2), Upstream river water (S3), and Downstream river (S4). The results obtained indicated that the physicochemical parameters of refinery effluent and river water bodies varied significantly (P<0.05). Parameters such as turbidity, Biochemical Oxygen Demand, Chemical Oxygen Demand, phosphate, ammonia, phenol, lead, cyanide, nickel and total coliform were all above maximum permissible limit as specified by Environmental Standards and Guidance for the Petroleum Industries in Nigeria (EGASPIN) in all stations while Parameters such as pH, temperature, sulphide, cyanide, vanadium, copper and zinc were all below permissible limit in all stations. Other parameters such as total suspended solids, total dissolved solids, and total chromium were above permissible limit in the river water than in the refinery effluent. However the concentration of heavy metals analysed on sediment samples in the river water were higher than the river water sample while other parameters were below permissible limit. Phytoplankton distribution and abundance among the sampling stations were very poor. A total of 40 taxas were recorded with 3 families namely; Bacillariophceae, Cyanobacteria and Chlorophyceae with Bacilliarophyceae dominating the entire phytoplankton distribution. Benthic organism distribution and abundance amongst the sampling stations were also very poor, a total of six species from the family Nereidae were recorded namely; Leonates decipiens, Dendronereis arborifera, Lopdorhynchus ucinatus, polycheate larvae, Capitella capitata and Arenicola spp. It was established from the results of this study that the refinery discharges had negative impact on the creek and adjoining river water qualities. Hence, extraction of water from these rivers for domestic and agricultural purposes requires some forms of physical and chemical treatment.
Description
A Thesis Submitted to the Department of Environmental Science, of the Kwame Nkrumah University of Science and Technology in Partial Fulfilment of the Requirements for the Degree of Master of Science (Environmental Science),