Comparative study of the acute toxicity of petroleum sludge on fresh and brackish water shrimp

摘要

The ecological impact of petroleum sludge on fresh water shrimp (Desmoscaris trispinosa)andbrackish watershrimp(Palaemonetes africanus) in the Niger Delta area was compared using the Organization of Economic Co-operation and Development (OECD) No. 218 protocol for sediment toxicity test. The shrimp were exposed to sediments treated with petroleum sludge at concentrations of 625, 1250, 2500, 5000 and 10000 mgkg-1. The LC50value obtained withD. trispinosa(1100 ± 160 mgkg-1) was lower than that obtained withP.africanus(1590 ± 336 mgkg-1). This was an indication that the petroleum sludge was more toxic to the fresh water shrimp than the brackish water shrimp. However, the observed mean LC50values were not significantly different at levels ofp0.01. These values indicated that petroleum sludge can have adverse effects on the fauna in the shoreline/benthic sediment of the Niger Delta ecological zone. Consequently, there is the need to protect sensitive invertebrates representing the major proportion of the diet of many species and humans.