Evaluation of the acute toxicity of refined petroleum products against Pila ovata (Gastropoda: Ampullariidae) and Poecilia reticulata (Teleostei: Poeciliidae)

Abstract

Static and static-renewal evaluation of the acute toxicity of three refined petroleum products — petrol, kerosene and diesel — against two freshwater animals, the mollusc Pila ovata and the fish Poecilia reticulata, was conducted in the laboratory. Petrol, kerosene and diesel were found to be moderately toxic to the test species, the 96h LC₅₀ values being in the low ml l⁻¹ range, but there was no consistent trend in the levels of toxicity recorded under the bioassay conditions. However, there was no significant difference (p > 0.05) in the toxicities of petrol, kerosene and diesel to individual test species in both the static and static-renewal bioassays. There were significant differences (p < 0.05) in toxicities of kerosene and diesel against Poecilia reticulata between both bioassays, by a factor of 7–8. Pila ovata was more susceptible to kerosene and diesel by the same factor as Poecilia reticulata was in the static bioassay. Differential toxicity of the refined petroleum products varied with the species tested, indicating that ranking of the order of toxicity of refined petroleum products cannot be generalised.