Biological impacts of oil pollution: A case study of the M/V Hebei Spirit spill in Taean, Korea

Abstract

The M/V Hebei Spirit spilled about 12,547 kl of crude oil into the west coast of Republic of Korea on December 7, 2007. More than 150 km of coastline were heavily oiled. Hanging culture facilities for oysters and in-land fish aquaculture facilities were directly affected by fresh crude oil. Many marine species were affected and were found dead. To clarify the impact on fish physiological response by oil spill, hepatic biomarker responses were measured in several fish species from Euhang-ri, where the impact was serious. Biomarkers were selected in order to evaluate the toxic effects on hepatic detoxification system exposed to PAHs. Level of Ethoxyresorufin O-deethylase (EROD), Cytochrome P-450 1A (CYP1A) mRNA and protein were measured on a weekly or monthly basis from four days after the oil spill. The uptake of PAHs by fish was indirectly measured by pyrene metabolite, 1-OH-pyrene, using synchronous fluorescence spectrometry. Fish bile showed highly increased 1-OH-pyrene levels four days after the oil spill and then decreased to the reference level according to time. A significant induction in EROD and CYP1A mRNA and protein expression were observed from five days after the oil spill, and then decreased to reference level, too. Acetylcholine esterase (AChE) activity was also slightly inhibited in initial fish samples compared to the reference site. Enzymatic biomarker levels increased rapidly in flatfish (marbled sole) caught at Euhang-Ri on 23, July 2008. These results correlated well with bile 1-OH-pyrene levels. Accordingly, biological activities (enzyme induction/inhibition) fluctuated along with PAHs levels, whenever a secondary release occurred. Expectantly, the levels of PAHs metabolites and biomarker response differed with fish species that are coming from different habitat with different behavioral trends, sensitivity and metabolic processes. Hence, risk assessment on the actual impact of oil spill on fish should consider these essential biological and