Lethal toxicity of industrial detergent on bottom dwelling sentinels

We used fresh and brackish water shrimp (Desmoscaris trispinosa and Palaemonetes africanus), in sediment bioassays to assess the toxicity of an industrial detergent containing high levels of anionic surfactant (linear alkylbenzene sulphonate (LAS)). The Organization for Economic Cooperation and Development (OECD), # 218 direct sediment toxicity assessment was employed. The organisms were exposed to different concentrations (31.25, 62.5, 125, 250 and 500 mg/kg) of the chemical (Neatex) in replicate treatments. Percentage mortality was measured as the ecological endpoint. Mean mortality and estimated lethal concentration LC50 values varied with species type, concentration and exposure duration. The statistical variation in the observed mean mortality of the test organisms in the chemical and the control treatment shows that mortality may be induced by the effect of the chemicals. The lethal concentration (LC(50)s) was significantly different at levels of p < 0.05 for the fresh and brackish water experiments. Consequently, assessment of water and sediment quality as a result of chemical pollutants was necessary for protecting some of the more sensitive benthic invertebrates representing the major proportion of the diet of many species in the Niger Delta ecological zone.