Long-term fate of crankcase oil in rainbow trout: A time- and dose-response study

Rainbow trout (Oncorhynchus mykiss) were exposed to waste crankcase oil, a recognized source of polycyclic aromatic hydrocarbon (PAH) contamination in urban runoff. Dietary exposure was to a mean concentration of 0, 3.5, 8.9, and 13 {micro}g oil/g fish, and sampling took place after 3, 7, 11, and 15 weeks. The accumulation of compounds in muscle tissue, the elimination of bile metabolites, the activity of 7-ethoxyresorufin O-deethylase (EROD) in liver, and morphometric variables were compared at the different concentrations and times of sampling. The concentration of fluorescing compounds in muscle displayed the best dose- and time-response pattern, whereas other biological, chemical, and biochemical responses were not as well defined. No correlation could be drawn between the concentration of PAH in the oil and the measured variables. The environmentally relevant concentrations used in the experiment show the importance of choosing broad and specific indicators of exposure in a multidisciplinary investigation and the need for further research in chemical and toxicologic areas.