| The toxicity of crude oil to the early life stages of fish has been linked to the presence and concentration of polycyclic aromatic hydrocarbons (PAHs). Fish chronically exposed to alkyl PAHs exhibit dioxin-like toxicity characterized by the presence of Blue-Sac Disease (BSD) and the induction of cytochrome P4501A (CYP1A). I compared the relative toxicity of four crude oils, Scotian Light (Scot), Medium South American Crude (MESA), Federated Crude (FED), and Alaska North Slope Crude (ANSC) of differing total alkyl PAH concentrations to early life stages (ELS) of rainbow trout (Oncorhynchus mykiss) in simulated spawning beds containing gravel contaminated with one of those oils. In the direct exposure experiment, cumulative mortality and BSD severity increased as the oil concentration increased. The differences in toxicity among oils were not as expected, indicating that the overall composition of oil is more important than total PAH when trying to predict toxicity from crude oil. The extent of BSD and CYP1A induction in the early life stages of rainbow trout (Oncorhynchus mykiss) and Japanese medaka (Oryzias latipes) was compared after exposure to two crude oils: Scot and ANSC. (Abstract shortened by UMI.)... |
