Physico-Chemistry of Surface Water Impacted by Crude Oil Spills in Bodo/Bonny Rivers, Nigeria

Abstract

The surface water resources of Bodo/Bonny communities in Rivers State suffers regular pollution of its ecosystem due to increase in crude oil exploration, refining and activities of other industrial establishments operating within the coastal areas of the Ogoniland of the Niger Delta region of Nigeria. This have resulted in the wide scale contamination of most of its creeks, swamps and rivers with hydrocarbons and dispersant products resulting in the alteration of the ecological integrity of fragile aquatic systems, bioaccumulation of chemical contaminants by zoobenthos, sediment enrichment, and smothering or asphyxiation of the organisms in water by oil coating, thereby causing death. These conditions have resulted in serious threat to public health and the ecosystems. The study was aimed at determining the physico-chemical characteristics of Bodo/Bonny coastal waters impacted by crude oil spills and their effect on the marine ecosystems. Surface water was collected from 5 stations (BBW1, BBW2, BBW3, BBW4 and LFPW5) with LFPW5 serving as control. Physico-chemical parameters were investigated following standard methods. The results of the physicochemical characteristics of the various sampling points in the dry season showed that pH, TDS and Electrical conductivity values showed statistically significant differences at P < 0.005. pH was slightly acidic in all sampling locations except for the Link fish pond, the values ranged from 6.20–6.40 which was below DPR Limit of 6.5-8.5 for potable water, TDS recorded 43175–57075 mg/L above DPR permissible Limit of 5000mg/L. Electrical Conductivity (EC) values ranged from 54050 -57050 µS/cm. The Dissolved Oxygen, Biological Oxygen Demand, Turbidity, Chloride recorded in this study varied significantly at P< 0.05. Results of the physicochemical parameters of surface water in the wet season fell within the standard limits except for the conductivity that was above the permissible limits. Comparatively the mean pH value of surface river water with Linked fish pond water which served as the control revealed that the Link fish pond water had the highest pH value of 7.9 than the surface river water samples with a pH of 6.4, TDS (60,200 mg/L), Electrical Conductivity (EC) (µS/cm3) followed a similar pattern with the mean EC value of 55,800 mg/L as against 750mg/L for the Link Fish pond water. Temperature recorded 310C as against 300C for the link fish pond while the Salinity (mg/L) of the surface river water was 31.63 mg/L. Dissolved Oxygen was 2.3 mg/L, Biochemical Oxygen Demand values for the surface river water was 0.49 mg/L while the Link fish pond water had 0.3mg/L. These values obtained in this study shows that the spilled oil in the water could impact on species abundance and biomass by depleting and depriving the fishes from available O2 for survival thus resulting in asphyxiation.