W5 PM Toxicity of Complex Mixtures
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in 321-323

(CLA-1117-817531) Crude oil fraction toxicity to early life stage Japanese medaka (Oryzias latipes).

Clarke, Lauren¹, Hodson, Peter¹, ¹ Queen's University, Kingston, Ontario, Canada

ABSTRACT- Crude oil is a complex mixture with each crude being unique in chemical composition and PAH concentration. The presence and concentration of polycyclic aromatic hydrocarbons (PAHs) has been linked to the dioxin-like toxicity in early life stages of fish exposed to crude oil. This toxicity has been characterized by the presence and severity of blue-sac disease (BSD) and the induction of cytochrome P4501A (CYP1A) enzymes. Two crude oils, Scotian Shelf (SS) and Alaska North Slope Crude (ANSC), were fractionated into 4 fractions (F1-F4), which were then used in chronic early life stage Japanese medaka (Oryzias latipes) toxicity experiments. Embryos were exposed to a chemically enhanced water accommodated fraction (CEWAF) of one of the fractions. The F3 fraction, which contains many PAHs and alkyl PAHs, was found to have the highest toxicity in both oils. F1 and F2 had high mortality which was attributed primarily to narcotic effects as toxicity scores remained relatively low. ANSC F4 had a relatively low toxicity in terms of both sublethal and lethal effects.

Key words: Toxicity, Oil, Fractions, early life stage fish