Environmental risk assessment of marine activities by Jan-Bart Calewaert et alii. – Parte I

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ARGOMENTO: EMERGENZE AMBIENTALI
PERIODO: XXI SECOLO
AREA: DIDATTICA
parole chiave: rischio ambientale marino
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Environmental risk assessment of marine activities
credit to Jan-Bart Calewaert et alii. Original article published by  www.coastalwiki.org

Introduction
In broad terms, risk assessment is the procedure in which the risks posed by inherent hazards involved in processes or situations are estimated either quantitatively or qualitatively. Environmental Risk Assessments (ERA) are carried out to examine the effects of an entity or agent on humans (Health Risk Assessment) and ecosystems (Ecological Risk Assessment). They cover a broad spectrum of risks, receptors and end-points: an ERA can focus on biological, chemical, radiation and/or physical risks towards impacts on receptors such as human beings (individuals or population), fauna and flora (single species or whole ecosystems), and materials (e.g. impacts on building by acid rain, loss or damage of property). For each of these risk receptors, different end-points are defined: for example mortality and morbidity in human health assessment, property loss in fire, revenue loss for people depending on the harmed ecosystem in the economic impacts assessment, extinction or total catch in ecological risk assessment. Dependant on which risks, receptors and end-points one wants to investigate, the steps and methods to be used in ERA will differ. An adapted approach of ERA is required since a general description of the key tasks and methods in risk analysis is not possible.

Environmental risk assessment of marine activities

The usefulness of a risk assessment of marine activities depends on the method(s) used and the purpose of the results. The analysis of risks can be approached in several ways, from very general and rough to very detailed. A risk analysis consists of several consecutive steps and for each step in the risk assessment process a number of methods are available.

Each of these methods come with advantages and disadvantages. A number of factors influence the most appropriate method to be used in a given circumstance, including the type of activities, the study area, potential gaps in data and/or models and the uncertainty issue of risk assessment. Here we focus on methods relevant to risk sources related to marine activities and to marine and coastal as potential receptor.

Quantitative versus qualitative risk assessment approaches
Depending on the characteristics of the problem under review and the availability and form of data required, the analist needs to decide upon the use of a qualitative, semi-quantitative or quantitative approach.All approaches have their own set of possible methods that can be used for each of the consecutive steps of the risk analysis. Quantitative risk assessmentQuantitative Risk Analysis (QRA) is the determination of the probability and consequences of potential losses in numerical terms. The assignment of probability values to the various events in the risk model provides for a quantitative assessment of risk.An important aspect of risk assessment is the estimation of the associated uncertainty.

Therefore, the process may be completed through the use of statistical models such as probability analysis, Poisson distributions or Bayesian theory. These statistical models require the use of past data and assumptions about future trends. Much of the data may be accumulated from different sources.^[1][2]

Qualitative risk assessment
Although the bulk of the effort in developing methods of risk analysis has been addressed to quantitative methods, critical aspects of risk frequently require qualitative evaluation. Qualitative risk analysis may use “expert” opinion to estimate probability (or frequency) and consequence (or impacts) often through linguistic expressions. Based on expert judgement different qualitative consequence categories can be defined in terms of for example high, medium, low, etc.

The same can be done for qualitative probability categories in terms of expressions as likely, may occur, not likely, very unlikely. This subjective approach may be sufficient to assess the risk of a system, depending on the decisions to be made and available resources. Formal processes for expert-opinion elicitation have been developed to provide consistency in qualitative information gathering (e.g. Delphi technique). Concerning qualitative uncertainty estimates, one has to rely on subjective estimates of uncertainty.[1]

Environmental risk assessment Within the quantitative and qualitative approaches a wide range of methods exist, each with its own characteristics, advantages and disadvantages and fields of application. The selection of a quantitative or qualitative method depends upon the availability of data for evaluating the hazard and the level of analysis needed to make a confident decision.However, not all of the relevant risk sources and receptor specific aspects can be covered in quantitative terms and quality data essential for accurate results are not always available. In this sense, a less detailed analysis based on the use of qualitative analysis methods can be appropriate. A semi-quantitative approach, using quantitative methods if possible and qualitative methods if needed, is a pragmatic and often the most suitable approach.

This illustrates that an adapted approach of ERA is required and that a general description of the key tasks and methods in risk analysis is not possible. There are however a number of unifying principles underlying all risk assessments. Despite the diversity of approaches, we can state that in general seven steps can be identified addressing the key questions in an Ecological Risk Assessment (ERA): Problem Formulation, Hazard Identification, Release Assessment, Exposure Assessment, Consequence or Effect Assessment, Risk Characterisation and Estimation and Risk Evaluation (Table 1).^[3][4]

Conclusions made in the Risk Characterisation and/or Risk Evaluation are used as input for Risk Management. 

Which actions should be taken and how should the remaining risks be handled? 

The different consecutive steps are presented in fig. 1 below:

Fig. 1 Presentation of the general key tasks in environmental risk assessment (Based on Fairman et al. 1999) [4]

Whatever method chosen, two major topics that need to be taken into account throughout each consecutive step of the risk assessment are:

(1) uncertainty rating
(2) quality assessment of the input.

Identification of potential gaps is also an important topic of risk assessment in order to assure the quality and relevance of the available information.

References 

1. Wilcox R. LT. Burrows M. CDR. Ghosh S. and Ayyub B. M. (2000). Risk-based Technology for the Safety Assessment of Marine Compressed Natural Gas Fuel Systems. International Cooperation on Marine Engineering Systems/The Society of Naval Architects and Marine Engineers. Paper presented at the 8th ICMES/SNAME New York Metropolitan Section Symposium in New York, May 22-23, 2000.
2. Stern P. C. and Fineberg H. V. (eds.) (1996). Understanding Risk – Informing Decisions in a Democratic Society. Committee on Risk Characterization, Commission on Behavioural and Social Sciences and Education – National Research Council.
3. Covello, V.T. and Merkhofer, M.W. (1993). Risk Assessment Methods Approaches for Assessing Health and Environmental Risks. Plenum, New York
4.  Fairman R., Mead C. D. and Williams W. P. (1999). Environmental Risk Assessment – Approaches, Experiences and Information Sources. Monitoring and Assessment Research centre, King’s College, London. Published by European Environment Agency – EEA Environmental issue report No 4.[1]
5. MacDonald A., McGeehan C., Cain M., Beattie J., Holt H., Zhou R. and Farquhar, D. (1999). Identification of Marine Environmental High Risk Areas (MEHRA’s) in the UK. Department of the Environment, Transport and the Regions, ST-87639-MI-1-Rev 01, London, UK.
6. ECOTOC (2001). Risk Assessment in Marine Environments. Technical Report No. 82. ISSN -0773- 8072-82. European Centre For Ecotoxicology and Toxicology of Chemicals, Brussels.

See also

• References for environmental risk assessment
• Case study risk analysis of marine activities in the Belgian part of the North Sea

Le Roy D., Volckaert A., Vermoote S., De Wachter B., Maes F., Coene J. and Calewaert JB. (2006). Risk analysis of marine activities in the Belgian Part of the North Sea (RAMA). Research in the framework of the BELSPO Global change, ecosystems and biodiversity – SPSDII, April 2006, 107 pp + Annexes. Available at [2]

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