Acute toxicity of crude oil from NNPC and artisanal refineries in Niger Delta on selected aquatic biota

The spill of Crude oil from artisanal refineries and government owned pipelines has become recurrent situation in the Niger Delta, leading to devastating effects on the aquatic ecosystem. The toxicity of Crude oil from NNPC (Nigerian National Petroleum Corporation) refinery and selected artisanal refineries in Bolo, Twon-Brass and Ekpemu of the Niger Delta were investigated. The physicochemical properties of the products from the artisanal refineries short fall of the standards of Crude oil for refineries, as they contained impurities. The toxicity of the Crude oil was tested using three representatives of different trophic levels in the aquatic habitat; Fish (Tilapia guineensis), Crusteceans (Paleamonetes africanus), and Moluscs (Tympanotomus fuscatus). The LC50, NOEC, LOEC, and TUa were the indices used for toxicity assessment of the crude oil on the test organisms. The study revealed that all the Crude oil samples were toxic to the organisms. The degree of toxicity of crude oil showed the following trend; Ekpemu (LC50 – 0.02ppt)> Twon-Brass (LC50 – 0.06ppt)> Bolo (LC50 – 0.11ppt)> NNPC (LC50 – 4.63ppt), while the degree of sensitivity was; Tilapia guineensis > Paleamonetes africanus > Tympanotonus fuscatus. The findings further emphasize the need to control Crude oil spillage into the aquatic ecosystem.