EFFECTS OF THE IRANIAN HEAVY CRUDE OIL ON THE EARLY LIFE STAGES OF ZEBRA FISH (DANIO RERIO)

Abstract

These studies were prompted by the Hebei Spirit oil spill examined and the effects of 12,547 kl of crude oil which were spilled from the tanker into the west coast of Korea. Three different kinds of crude oils (Iranian Heavy, KEC and U/Zkum) were spilled from the punctured tanks. To clarify the effects of the spilled oil on fish early life stages, A laboratory study was conducted using zebrafish embryos. Zebrafish embryos (96 h post-fertilization) were exposed to gravel containing Iranian Heavy Crude (IHC) oil at a concentration of 6g/kg for 72h. Embryos were manually dechorionated and observed by a stereomicroscope and a compound microscope. Embryos were fixed in 4% phosphate-buffered paraformaldehyde and stained for CYP1A and myosin heavy chain. After 48 hr, several complex effects, including the edema and tail mutation were observed. 65% and 80% of embryos showed pericardiac edema and tail abnormality, respectively. About 90% of embryos showed pericardiac edema and tail abnormality after 72hr. 19 PAHs and alkylated PAHs concentrations in water were measured. Naphthalene dominated in oiled gravel. Tricyclic PAHs were accounted 82-89% of 19 PAHs and alkylated PAHs accounted for 16-27. The distribution of CYP1A in embryo was assessed by immunofluorescence. CYP1A immunofluorescence activity was visible in the endothelium of head, the epidermis and the endocardium. Our results confirm that Zebra fish embryos exposed to IHC may suffer disrupted cardiac function and fish tail during development both of which are highly relevant for fitness and survival.