Effects of the ‘Prestige’ oil spill on cellular biomarkers in intertidal mussels: results of the first year of studies

In November 2002 the tanker ‘Prestige’ sunk in front of the Galician coast (NW Iberian Peninsula). As a result, >60 000 t of heavy fuel oil leaked into the sea, affecting >1000 km of coastline. In order to assess the effects of the oil spill on coastal ecosystems, mussels Mytilus galloprovincialis were sampled (April, July and September 2003) in 17 locations along the Galician and Bay of Biscay coasts. In this study, 3 biomarkers were assessed: lysosomal responses as changes in the lysosomal structure and in the lysosomal membrane stability, accumulation of intracellular neutral lipids and peroxisome proliferation as induction of acyl-CoA oxidase (AOX) activity. Mussel flesh condition index and gonad developmental stages were assessed as supporting parameters. Lysosomal membrane stability was reduced in mussels from all locations, indicating disturbed health, especially in mussels from all Galician locations. Similarly, lysosomal enlargement was observed in most locations, as shown by relatively low values of the surface-to-volume ratio, although the volume density of lysosomes was low due to decreased lysosomal numbers. Overall, intracellular accumulation of neutral lipids was conspicuous in digestive tubules of mussels collected in July and was increased further in September. AOX induction was detectable in mussels sampled in April, except for those collected in Galicia. In July mussels from the most impacted stations in Galicia, Caldebarcos and Camelle, showed the highest AOX values. In conclusion, the biomarkers employed detected exposure to toxic chemicals and a disturbed status of health in mussels from the northern Iberian Peninsula after the ‘Prestige’ oil spill and will allow assessment of the long-term effects of the spill on the coastal ecosystems.