Page 5 - Assessment

D. Melaku Canu et al. / Marine Pollution Bulletin xxx (2015) xxx–xxx 5
P P
X s x 2015), risk assessment is a methodology to determine the nature
HI s;i ¼ HI R;s;i ¼ R P t¼0 i;s
s
x
max½ t¼0 i;s Š and extent of risk by analysing potential hazards and evaluating exist-
R
ing conditions of vulnerability that together could potentially harm
Results are averaged over 4 seasonal groups defined as follows: exposed people, property, services, livelihoods and the environment
1-Winter, (January to March), 2-Spring, (April to June), 3-Summer on which they depend. Risk assessments include: a review of the tech-
(July to September), and 4-Autumn, (October to December). nical characteristics of hazards such as their location, intensity, fre-
Only averaged and normalized results are given because sim- quency and probability; the analysis of exposure and vulnerability.
ulation results do not represent the actual impact of any specific, The Ecological Sensitivity Index (ESI) was computed from a geo-
real, oil spill accident but are only a statistical characterization of referenced Site of Community Importance, SCI, and Special
the most likely trajectories following a hypothetical release in a Protection Areas, SPA, (SCI and SPA) database, released by the
given area under the typical conditions of a given season. Regional Authority (Sicily Region, www.sitr.regione.sicilia.it). We
assumed that the ESI of the areas close to protected SCI or SPA
2.4. Risk assessment habitat (distance shorter than 1500 m) was twice that of areas fur-
ther away from protected habitats and coded the former with a
A comprehensive risk index was calculated by combining a 10- factor value 2 and the latter with a factor value 1. This choice is
day seasonal hazard index with an Ecological Sensitivity Index, a clearly subjective and rather conservative and should be revised
vulnerability index expressed as the level of protection of habitats based on the results of ad hoc valuation exercises wherever they
along the shore. are available.
According to the definition given by UNISDR (The United The 10-day hazard index was calculated as HI 10,i , computed for
Nations Office for Disaster Risk Reduction, http://www.unisdr. each season, smoothed in space using a biweight kernel density
org/we/inform/terminology#letter-r, last visit February 17th,

Fig. 3. Seasonal surface residual circulation; Top panels: Winter (W), Summer (S), bottom panels, Spring (S), Autumn (A).
Please cite this article in press as: Melaku Canu, D., et al. Assessment of oil slick hazard and risk at vulnerable coastal sites. Mar. Pollut. Bull. (2015), http://
dx.doi.org/10.1016/j.marpolbul.2015.03.006