Assessment of the Toxic Effect of Oily Drill Cuttings on Mangrove Littoral Periwinkle (Tympanotonus Fuscatus) of the Lagos Lagoon

The acute toxicity of oily drill cuttings against the littoral mangrove periwinkle (T. fuscutas) of the Lagos Lagoon was evaluated in the laboratory bioassay. In this study, the result showed that the acute toxicity of oily drill cuttings based on immobility response of Tympanotonus fuscatus increased with time of exposure. The concentration that caused 50% immobility in the organisms at 24hrs, 48hrs, 72hrs and 96hrs were 3808.80ml/L 660.89ml/L, 302.28ml/L and 102.43ml/L respectively. The median lethal concentration of drill cuttings against T. fuscatcus decreased as the duration of exposure increased. The analysis of variance (ANONA) showed that there was significant difference (p< 0.05) between all the treatments at 24, 48, 72 and 96 hours of exposure. The significance of these result is the need to include bio accumulators such as T.fuscatus in monitoring programmes aimed at establishing the environmental level of such pollutant as oily drill cuttings in aquatic ecosystem.