Toxicological Evaluation and Usefulness of Lipid Peroxidation as Biomarker of Exposure to Crude Oil and Petroleum Products Tested against African Catfish, Clarias gariepinus and Hermit Crab, Clibanarius africanus

The toxicological evaluations of crude oil, petrol, kerosene and diesel were carried out against the African Catfish (Clarias gariepinus) fingerlings and Hermit crab (Clibanarius africanus). On the basis of 96hr LC₅₀ value, petrol (LC₅₀ = 2.449 mL/L) was found to be the most toxic followed by diesel (LC₅₀ = 7.839 mL/L), kerosene (LC₅₀ = 8.095 mL/L), and crude oil (LC₅₀ = 9.355 mL/L) to Clarias gariepinus. For Clibanarius africanus also, petrol (LC₅₀ = 4.569mL/L) was the most toxic followed by kerosene (LC₅₀ = 8.705 mL/L), diesel (LC₅₀ = 13.852 mL/L) and (LC₅₀ = 35.955 mL/L). On the basis of the computed susceptibility factor, hermit crab was found to be 2x, 2x, 6.1x and slightly more tolerant than catfish when exposed to petrol, diesel, crude oil and kerosene respectively. The results of the lipid peroxidation assay against juveniles of C. gariepinus showed that the level of malondialdehyde (MDA) in the liver of fish exposed to sublethal concentrations of all the test chemicals increased significantly when compared to control animals. The observed increase in MDA levels in the liver tissues of test animals exposed to crude oil and refined petroleum products was recommended as a good biomarker for early detection of oil related pollution during biomonitoring programmes.