Preliminary Investigation of Comparative Toxic Effects of Locally Formulated and Commercial Demulsifiers on C-Callichytes Fingerlings

Demulsifier is one of the crude oil production chemicals that constitute the contaminants in the resulting produced water that is usually discharged into the marine environment. Most commercial demulsifiers list the toxic effects of individual components of their formulations which on application, may require the addition of one or more other chemicals. The synergic effects of these components in the final products are not usually accounted for. Different concentrations (10, 20, 30, 40, 50, 60 and 70 mg/l) of a typical commercial and locally formulated demulsifiers were application-ready prepared. Each concentration was introduced into an aquarium containing 20 Callichthyes callichthyes fingerlings with an average weight of 9.73 g and observed for 60 hours. The values for 36-hour LC50 of the formulated demulsifier was found to be higher than that of the commercial one by 15.75 mg/l, using Miller & Tainter method and 18.70 mg/l in the arithmetic of Karber method. These preliminary results show that there is a difference between the toxicity of the individual components of the demulsifiers and their final formulations or when mixed with other chemicals at application stages.