2007_6_Nr6_EEMJ

Robu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 573-592
environmental competent authority to request a risk
assessment with the aim at evaluating the probability
of harm and at finding the possible prejudiced
entities. Not every site affected by a certain pollutant
will exhibit the same risk or will need the same level
of remediation. The risk assessment is defined by the
World Bank as being a process for identification,
analysis and control of the danger appeared due to
the presence of a hazardous substance into a plant.
The Report from 1992 of the British Royal Society
explains the sense of the definition given in the
Directive European Commission 93/67/EEC,
enlightening the components of risk assessment,
meaning the risk estimation and calculus.
In consequence, the risk assessment involves
an estimation (including the identification of the
hazards, the magnitude of the effects and the
probability of occurrence) and a calculus of the risk
(including the quantification of the danger importance
and consequences for humans and/or environment).
Risk assessment aims at controlling the risks
produced on a site by identification of:
• Pollutant agents or the most important
hazards;
• Resources and receptors exposed to the risk;
• Mechanisms of risk accomplishment;
• Important risks that emerge on the site;
• General measures needed for reduction of
the risk to an accepted level.
The risk depends on the nature of impact
upon the receptors but also on the probability of the
occurrence of this impact. Identification of the critical
factors that influence the relationship source-pathreceptor
involves the detailed characterization of the
site from physical and chemical point of views.
Generally, the quantitative risk assessment
encloses five stages:
• description of the aim;
• identification of the hazard;
• identification of the consequences;
• estimation of the magnitude of the
consequences;
• estimation of the probabilities of the
consequences.
Concordant to Order to 184/1997, the risk is
the probability that a negative effect to occur in a
specified period of time and is often described by the
relation:
Risk = Danger x Exposure
The risk assessment implies the
identification of the hazard and of consequences that
may appear as a result of occurrence of the events
considered as risk sources. In function of the
importance of the consequences one may decide if
there is necessary or not to take remediation
measures. Concordant to the Order no. 184/1997, the
risk quantification is based on a simple system of
classification, where the probability and severity of an
event are descendent distributed, being assigned with
an arbitrary score:
Simplified model
Probability Severity
3 = high 3 = major
2 = medium 2 = medium
1 = low 1 = insignificant
This model is used not only for qualitative,
but also for quantitative risk assessment. Thus, the
risk may be calculated by multiplying the two factors
(probability, severity) in order to obtain a
comparative number, for example 3 (high probability)
x 2 (medium severity) = 6 (high risk). This allows the
comparison of different risks.
The greater the results, the bigger the priority
should be given to risk control. This basic technique
may be developed for allowing more serious analysis
by increasing the range of the scores for classification
and by considering a bigger number of improved
definitions for major severity, increased probability
etc. When a big number of important pollutants are
considered for assessment, an increased attention
should be paid to a clearer manner of presentation. It
is often necessary to summarize the information as a
control list or matrix.
4. Quantitative risk analysis for port hydrocarbon
logistics
4.1. Brief review
Over the last few decades much experience
has been gained in the field of risk analysis of
standard chemical or petrochemical plants.
Nowadays, this knowledge is being applied to a wide
range of industrial activities involving hazardous
materials handling, including ports (Crowl, 2002,
Gavrilescu, 2003; Robu, 2005). Nevertheless, few
works approached the application of QRA to
navigational aspects and terminal operations are
available, and this is to the role played by SEVESO II
Directive. This method allows quantitative risk
analysis (QRA) to be performed on marine
hydrocarbon terminals sited in ports. A significant
gap is identified in the technical literature on QRA for
the handling of hazardous materials in harbors
published prior to this work Ports are environments
often overloaded with hazardous materials, both in
bulk and containerized.
The method described here is proposed
within a Spanish project called FLEXRIS and applied
to the premises of the port of Barcelona, one of the
largest ports on the Mediterranean Sea (Ronza et.al.,
2006). Several risk assessment reports, made
available to the public, proved to be a valuable source
of information. What these works lack is an attempt at
standardizing the process of risk assessment of
navigation and loading operations for a generic
port/terminal.
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