1. Variations in the V and Ni content in mussels after the Prestige spill VERTIMAR-2005 SYMPOSIUM ON MARINE ACCIDENTAL OIL SPILLS Vigo, Spain, 13-16 July 2005 Vigo, Spain, 13-16 July 2005 V. Besada, F. Schultze, J.A. Soriano, L. Viñas, A. Franco, B. Cambeiro, J.J. González Instituto Español de Oceanografía, Centro Oceanográfico de Vigo, 36280 Vigo, Spain

2. Introduction  The 13th of November 2002 and during the following months, the tanker Prestige released part of the 77.000 t of fuel  The Galician and Cantabrian Spanish coast were more of less impacted by the fuel spill  The concentrations of V and Ni in the Prestige fuel were 170 ± 5 mg/kg and 55 ± 1 mg/kg for V and Ni respectively

3. Objectives of the study  Estimate in Corrubedo and Punta Insua, two of the most affected areas by the fuel spill, the temporal evolution of the concentrations of vanadium and nickel in wild mussels (Mytilus galloprovincialis) during two years after Prestige accident  Observe the relation of V and Ni with the Polycyclic Aromatic Hydrocarbons (PAHs) concentrations

4. Sampling 4000 m 13°12°11°10°9° 43° 42° PUNTA INSUA CORRUBEDO vessel broke in two Drifting vessel 13/11/02

5. Sampling  The wild mussel was chosen as a pollution indicator, as this is a sedentary species, has a wide geographic distribution, has enough size, is easy to sample and easily accumulates pollutants, reflecting the environmental conditions of the area in which it lives  Analyses were made in pools of mussel soft tissue containing 50 individuals minimum, representing all sizes present in the sampling point. The homogenates were triturated with Ultraturrax and freeze-dried. The samples were homogenized again and stored until their analysis.

6. Chemical Analysis and Quality Control  The analysis of trace metals includes a nitric acid digestion in a microwave and V and Ni were analyzed by ETAAS with Zeeman background correction.  After Soxhlet extraction followed by extract cleaning using column chromatography with desactivated alumina, 13 PAHs have been determined using high performance liquid chromatography, with wavelength-programmable fluorescence detector.  The laboratory internal QC includes duplicate samples,the use of certified reference materials as well as participation in international intercomparison exercises, such as QUASIMEME, on a regular basis.

7. Comparison of V and Ni with other elements

8. Comparative evolution of V and  PAHs

10. Comparative evolution of Ni and  PAHs

12. Summary  No variations in the metals concentrations usually analysed in the National Monitoring were observed due to the Prestige  When comparing the evolution in the V and sum PAHs concentrations along the different sampling surveys, a temporal difference of 4-6 months between the occurrence of the maximum of sum PAHs levels and the maximum of V has been shown.  For V and Sum PAHs the concentrations in the mussels decrease quickly, getting to normal values in some months after the accident

13. Summary  The Prestige influence is not clearly showed in the temporal evolution of the Ni concentrations.  A. Dufour has reported a similar evolution after the Erika spill

14. Acknowledgements  The authors would like to thank the Spanish Ministry of Science and Technology for the financial support (VEM2003-20068- C05-03).