Joint action toxicity of spent lubrication oil and laundry detergent against Poecilia reticulata (Telostei: Poeciliidae)
Single and joint action bioassays using spent lubrication oil, laundry detergent and a mixture of both (based on a 1:1 ratio of their 96h LC50 values) against the guppy Poecilia reticulata were carried out. On the basis of 96h mortality data, laundry detergent (LC50 value - 0.033g l−1) was found to be approximately 1 147 times more toxic than spent lubrication oil (96hrs LC50 — 37.72g l−1) when acting singly against P. reticulata. Joint action bioassays revealed a synergistic effect, with the mixture of the two test compounds being about 12 000 and 10 times more toxic, respectively, than either spent lubrication oil or laundry detergent acting singly. The significance of these results should affect both local and national waste disposal management policies.