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Marine Pollution Bulletin 84 (2014) 44–55

Contents lists available at ScienceDirect

Marine Pollution Bulletin

journal homepage: www.elsevier.com/locate/marpolbul

Oil spill hazard assessment using a reverse trajectory method
for the Egadi marine protected area (Central Mediterranean Sea)

Achille Ciappa a,⇑ , Salvatore Costabile b
a
e-geos/ASI-Telespazio, via S. Cannizzaro 71, 00156 Roma, Italy
b
Ministero dell’Ambiente e della Tutela del Territorio e del Mare, Via Cristoforo Colombo 44, 00147 Roma, Italy
ar ti c l e i nf o ab stra ct
Article history: The Egadi Marine Protected Area (MPA) on the western side of the Sicily Channel (Central Mediterranean)
Available online 13 June 2014 is exposed to a high risk of oil pollution from the tanker routes connecting the eastern and western basins
of the Mediterranean Sea. Areas where an oil spill would do most damage, and thus where surveillance
Keywords: should be concentrated, are identified in this study by Lagrangian tracers tracked backwards in time from
Oil pollution transport points along the MPA perimeter using data spanning six years from 2006 to 2011. Results indicate that
Marine protected area the areas where oil surveillance would be most beneficial are segments of the tanker routes south of Sic-
Egadi archipelago
ily (highly frequented) and north of Sicily (scarcely frequented), both extending about 150 miles from
Lagrangian tracers
Backward-in-time integration November to March and 100 miles in the other months. The third route, close to the Tunisian shore, is
the most frequented by oil tankers but the threat period is limited to November and December.
Receptor mode
Ó 2014 Elsevier Ltd. All rights reserved.

1. Introduction The Marine Protected Area (MPA) of the Egadi archipelago, on
the western tip of Sicily in Central Mediterranean (Fig. 1), is very
Oil tanker routes in the Mediterranean Sea connect pipeline close to the main tanker routes connecting the Western and
terminals, refineries and offshore platforms concentrated along Eastern basins of the Mediterranean Sea and for this reason is
the coastal zone of Southern Europe, North Africa, the Middle East exposed to a high risk of oil pollution. A method for the identifica-
and the Black Sea, and account for more than 20% of global oil tion of the risk areas, i.e. where the occurrence of an oil spill would
tanker traffic. A great threat to the marine environment of the do most damage, is proposed in this study and applied to the Egadi
Mediterranean Sea comes from oil drillings and illegal discharges archipelago MPA. The intersection of these areas with the main
(Alpers and Huhnerfuss, 1988; Pavlakis et al., 2001). According to tanker routes indicates where to concentrate the monitoring effort,
the European Space Agency (1998), about 45% of the total oil pol- for instance by monitoring satellite data.
lution comes from regular spills along these routes while only 5% is Recent increases in modelling capability have made possible the
caused by large accidental oil spills (Fingas, 2001). incorporation of marine dynamics in techniques for the reduction
Satellite monitoring by Synthetic Aperture Radar (SAR) is an of environmental risks stemming from shipping offshore and
effective tool for discouraging the illegal practice of oil discharge coastal activities. Lagrangian trajectories have been used to
(Brekke and Solberg, 2005). Satellite images, if acquired at the right investigate the drift pattern induced by currents in the Baltic Sea
time and place, provide early warning of dangerous spills and and in the Gulf of Finland with the aim of identifying safe routes,
enable prosecution of the polluter, eventually acting as a deterrent in order to minimize the probability of coastal pollution and/or
(Ambjörn, 2008). Unfortunately, in the Mediterranean as in other to maximize the time before which adverse effects are seen at
highly frequented seas, the amount of data necessary to monitor the coast (Soomere et al., 2010; Lu et al., 2012; Soomere et al.,
the main tanker routes is very large and is beyond the capability 2014). More specific to oil pollution, trajectory analysis has been
of the current SAR constellations. More frequent surveillance is used to investigate the risk posed by oil-dumping from ships along
required in specific sea areas where the oil is quickly pushed to the German North Sea coast (Chrastansky and Callies, 2009), in the
the coast by the prevailing winds and currents rather than dispers- Gulf of Finland (Murawski and Woge Nielsen, 2013) and in the
ing offshore, or reaches a long portion of the coast rather than a Strait of Bonifacio in the Mediterranean Sea (Olita et al., 2012) dur-
short one. ing reconstructions of atmospheric winds and marine currents
spanning several years. A specific study on the current-driven risk
⇑ Corresponding author. Tel.: +39 06 40793672; fax: +39 06 40796202. of pollution for MPAs was carried out in the Gulf of Finland
E-mail address: achille.ciappa@e-geos.it (A. Ciappa). (Delpeche-Ellmann and Soomere, 2013). The common aspects of

http://dx.doi.org/10.1016/j.marpolbul.2014.05.044
0025-326X/Ó 2014 Elsevier Ltd. All rights reserved.