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generating probabilities contours for surface water and coastline. The generated scenarios were considered, for 2005,summer (February to April) and winter (May to June) conditions, respectively. The chosen oil volume for these scenariosconsidered worst case discharge, according to national federal legislation (Brasil, 2008), and for this example,consisted in the whole capacity of an oil tanker. Duration of the spill event was instantaneous and simulated a collisionfollowed by total rupture of ship hull and immediate release of all stored oil into the sea. The model used asexample the MF380 oil, which is the main fuel used in ships, which is a heavy oil, persistent with low solubility inwater, presenting also high toxicity.ESI Maps and their crossing with the probabilities of oil contact define a comprehensive matrix for measuring theimpact of oil in coastal environments. Negative and positive symbols codify the sensitivity as low ESI (-); median(+/-); high (+) and very high sensitivity (++). The same criteria apply to the probabilities. The crossings of sensitivitywith probability, using the pre-established codes, classify the vulnerabilities into categories: low; medium; highand very high, thus generating an Index of Environmental Vulnerability to Oil (IEVO), as shown in Table 1. Thus,for example, the IEVO 2 (low vulnerability), is determined by crossing the ESI 1 and 2 (-) with the probabilitiesbetween 1 and 20% (-). According to this index, the regions where oil does not touch the coast (0% probability)were classified as IEVO 1 (no damage or not measurable damage).Table 1. Index of Environmental Vulnerability to Oil (IEVO): IEVO 1 – no damage or not measurable damage; IEVO 2 – lowvulnerability; IEVO 3 – median vulnerability; IEVO 4 – high vulnerability; and IEVO 5 – very high vulnerability.Probability (%)ESI 0 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-1001 1 2 2 3 4 4 4 4 4 4 42 1 2 2 3 4 4 4 4 4 4 43 1 3 3 3 4 4 4 5 5 5 54 1 3 3 4 4 4 4 5 5 5 55 1 3 3 4 4 4 4 5 5 5 56 1 3 3 4 4 4 4 5 5 5 57 1 4 4 4 5 5 5 5 5 5 58 1 4 4 4 5 5 5 5 5 5 59 1 4 4 4 5 5 5 5 5 5 510 1 4 4 4 5 5 5 5 5 5 5Index of Environmental Vulnerability to Oil – IEVOResults and discussionAlthough we have generated vulnerability maps for the summer and winter, only the winter map is presented inthis paper since for this scenario the affected area was broader than the other one, comprising a 230 km coastline.For winter, 74% of coastline was classified as IEVO 3 (median vulnerability), 18% received IEVO 1 (no damage ornot measurable damage), 17% was IEVO 2 (low vulnerability) and 1% IEVO 4 (high vulnerability) (Figure 1). Forthe summer scenario, oil would affect 150 km coastline, with 48% IEVO 3, 30% IEVO 1, 12% IEVO 2 and 8% IE-VO 4. It is important to emphasize that the vulnerability of a region changes according to different meteorologic andoceanographic conditions. The map represents pre-established conditions for type and volume of spilled oil at a specificspilling point. Such variation of environmental vulnerability to oil and its dependence of meteorological andoceanographic conditions was also reported (Romero et al., 2011; Olita et al., 2012).We propose a more consistent method of approach for oil impact classification, as it allows very high vulnerabilityeven in environments with lower sensitivity classifications. Areas with lower ESI (as dissipative beaches withmedium to fine sands and exposed dunes fields) may be considered with very high vulnerability, if they present>61% probabilities of being affected by oil. According to Silva et al. (2012), vulnerability indices below ESI 6 (andhigher) for such cases may be considered very high (gravel beaches, calcareous detritus coast, exposed ripraps).46