Toxicity evaluation of effluent from the de-oiling works of a decommissioned Nigerian crude oil pipeline using Palaemonetes africanus

Abstract

Oil industry activities often involve the cleaning and replacement of pipelines, usually resulting in the discharge of effluents into waterbodies. The toxicity of de-oiling effluent from a decommissioned crude oil pipeline in the Niger Delta region of Nigeria was assessed using the brackish water shrimp Palaemonetes africanus in a 96 h laboratory bioassay. On the basis of the computed 96 h LC₅₀, the effluent showed a significant dose-dependent relationship in its toxicity between 24 and 96 h of exposure. The 96 h LC₅₀ was 4.6 times more toxic than the 24 h LC₅₀, indicating that the toxicity of the effluent increased over the study period. Besides crude oil and refined petroleum products, which are often the major concern for regulators, there is a need for the proper enforcement of standards and safe limits for effluents prior to discharge so as to protect sensitive marine species.