RIASSUNTO
Abstract
Oil spill dispersants (OSD) are known to be effective tools needed to clean and disperse oil spills. One major concern in the use of dispersants is their toxicity. The toxicity of individual chemicals may be known and be of no concern, but when combined with other chemicals they can have unknown additive or synergistic effects. This study was therefore designed to investigate the toxicological effects of OSD Seacare and Bonny light crude oil on the African Catfish (Clarias gariepinus). The 96hr acute toxicity of the water accommodated fraction (WAF) of the mixture of OSD Seacare and Bonny light crude oil was investigated as well as the critical body residue on the fingerlings of the African Catfish. The mean (±SD) weight and height of the fish was 1.27±0.37g and 5.35±0.57cm respectively. The following concentrations, 30, 90, 180 and 270ml/L, were used for the definitive test of the CEWAF. The LC50 for the CEWAF was determined to be 199.289ml/L while no death was recorded in the WAF-co. The oil spill dispersant Seacare synergized the toxicity of the crude oil on the test organism by more than 4.516 times further proving that oil spill dispersants can and do synergize the toxicity of crude oil on aquatic organisms. There was no PAH recorded in the fish from the control. From the fish exposed to 30ml/L of the dispersed oil concentration, the total PAH concentration was 0.730227ppm with 1 Benzo (g,h,i) perylene accounting for the total amount. Whereas the total PAH in the fish exposed to the 270ml/L concentration was 2.52903ppm with Naphthalene accounting for the total amount. After the acute toxicity testing and the test organisms were put in clean water, it was noticed that the test organisms exposed to the dispersed oil had a change in colour and there was reduced feeding in both those exposed to the WAF of the crude oil and dispersed oil.