Analytica Chimica Acta 524 (2004) 27–32 Laser cleaning of Prestige tanker oil spill on coastal rocks controlled by spectrochemical analysis M.P. Mateo ∗ , G. Nicolas, V. Piñon, J.C. Alvarez, A. Ramil, A. Yañez Laboratorio de Aplicaciones Industriales del Láser, Centro de Investigaciones Tecnológicas, Universidad de A Coruña, Ferrol E-15403 (A Coruña), Spain Received 2 December 2003; received in revised form 29 March 2004; accepted 9 April 2004 Available online 23 July 2004 Abstract The potential of laser technology for controlled clean-up and analysis of Prestige tanker oil spill from coastal rocks is examined. Some of the massive cleaning methods cause more damage on the environment than they want to prevent. Laser treatment offers advantages with respect to these techniques such as the absence of additional residues and a minimal damage to the underlying substrate material. For these reasons, laser cleaning is presented as an alternative or complementary method in spills response available for minimizing their impact on the environment and human health. Test results of the yield of the laser cleaning process performed by a Nd:YAG laser emitting at two wavelengths are presented for various types of rocks polluted by the spill found on the north Galician coast. The laser cleaning process is controlled by the spectral analysis of the emission from the laser-produced plasma in order to avoid damage to the original rock surface. In order to provide complementary data, a morphological and compositional comparison of polluted and cleaned pieces has been performed by scanning electron microscopy and energy dispersive X-ray spectroscopy. © 2004 Elsevier B.V. All rights reserved. Keywords: Laser cleaning; Laser-induced plasma spectroscopy; Oil spill; Elemental analysis; On-line control 1. Introduction The oil spill from the Prestige tanker has devastated large sections of the Galician coastline in Spain since Novem- ber 2002 [1]. This environmental and economical disaster has demanded the development of fast, controlled and envi- ronmentally harmless cleaning techniques for fuel removal. Classical mechanical (water stripping) and chemical (disper- sants) procedures for rocks cleaning are difficult to control and generate waste and debris that require complementary techniques for their removal [2–4]. On the other hand, while chemical agents can be toxic, water washing can cause the sterilization of rocks by the elimination of sediments and nu- trients. Therefore, despite the final clean aspect of the rocks, these methods may cause more environmental damage than fuel by itself and are not recommended in some contam- inated zones that are specially delicate. New technologies ∗ Corresponding author. Tel.: +34-981337400x3411; fax: +34-981337416. E-mail address: pazmateo@udc.es (M.P. Mateo). have been developed, including bioremediation, which uses microorganisms to breakdown the hydrocarbons into less harmful compounds, but their ecological impact and appli- cability are still under study [5]. Laser technology described in this paper is proposed for the first time as an alternative or complementary technique for the clean-up of fuel spill from rocks in specific zones of the coast where classical cleaning procedures are too ag- gressive and damaging due to the waste generated or to the uncontrolled cleaning process itself. This can be the case in some zones of harbours, docks and natural protective spaces that require a more precise and harmless treatment or where the presence of waste or chemical agents is not acceptable. Another part of the Galician coast that cannot be cleaned by mechanical methods but requires a “softer” method such as that proposed here is the so-called “Museum of the German”, an open-air beach museum of stone, wooden and bone sculp- tures situated in the Galician fishing village of Camelle and constructed by a German hermit. This place had been a pop- ular tourist attraction for those visiting the Galician coast until it was damaged by the oil spill. 0003-2670/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.aca.2004.04.066