Effect of treated BAPCO oil refinery effluents on the marine environment in Bahrain

Abstract

The aim of this thesis was to study the effect of the treated oil refinery effluents of Bahrain Petroleum Company ( BAPCO ) on the marine environment. The study has been carried out in seven chapters, the first de~ling with general introduction about the physical environment of the Arabian Gulf and its oil industry in addition to marine pollution and fishery in Bahrain. The second chapter was aimed at studying the quality of water at different areas in Bahrain to compare it with the quality of water at an area adjacent to the refinery outfalls. The third chapter deals with the impact of the refinery on the marine environment. The research approach adopted was ecological and observational I involving water and sediment analysis. The fourth chapter was aimed at studying the effects of the refinery effluents on the fish through toxicity tests and estimation of trace metals and hydrocarbons in the fish tissues. The studies were conducted with several effluents from the main and side streams of the refinery, outlets of the induced air flotation unit and Sitra separator. The fifth chapter was aimed at studying the effect of Sitra oil storage tanks treated effluent on the intertidal fauna of the adjacent area. The sixth chapter deals with a general discussion on the whole studies. While the seventh chapter deals with sions and recommendations. From the study conducted , it could be said that in general the water quality of the western and northern regions of Bahrain is better than the water quality of the eastern region. The east has in general higher pH, higher ammonia, higher nitrite, lower nitrate, and higher phosphate levels than the other regions. The higher concentrations of all these substances reflects the urbanisation and industrialisation of this part of Bahrain and the consequent discharges of waste material. The fish, safee, were tested with different concentrations of the refinery main stream effluent using both short and long term exposures. The same experiment was set up using effluents from the side stream, the I.A.F. discharge of the refinery and Sitra separator outlet. The results indicated a greater toxicity of pollutants in the I.A.F. and Sitar separator effluents than in the main and the side stream effluents. The lethal concentration of I.A.F. and Sitra separator effluents which brought death to fifty percent of the test population of fish (safee) within 96 hours was approximately twenty percent. Fish from the experimental media showed a higner concentration of heavy metals. The study of the effect of Sitra oil storage tanks treated effluent on the intertidal fauna of the adjacent area revealed that no fauna was found at stations located just outside the effluent outlet. The sediment of these stations was black, slimy, heavily oiled with a bad smell and contains dead shells and turrets. Away from the effluent, a diverse fauna was found. It is concluded that the BAPCO refinery has a measurable impact on the marine environment of the east coast of Bahrain, and recommenqations are made tor the development of future policies with regard to Bahraini coastal waters.