Environmental Engineering Reference
In-Depth Information
The decision as to the identifi cation of the RA end-point is made by the risk
assessor 7 and depends on the assessor's objectives, values, and abilities (Cothern
1996 ; Kirchsteiger et al. 1998 ). The perception of values can be highly diverse
(Cothern 1996 ; Kirchsteiger et al. 1998 ; Souvorov 1999 ), e.g., the preservation of
the native biological diversity in an environment will bear extraordinary value to a
biologist whereas it might have a comparatively lower value to other stakeholders.
A reverse relation would probably be observed when economic effects are consid-
ered (e.g., effects on fi sheries and aquaculture). Therefore, we conclude that the
perception of the degree of risk (within a broader circle of stakeholders in a state
and usually in direct correlation to the country's level of development) exerts a sig-
nifi cant infl uence on the acceptability degree of each risk.
Risk Assessment Errors
RA includes potential errors which can occur at any assessment step. The errors can
be divided into two groups (Hayes 2000 ):
￿
Type I errors - to cause overestimates of the real risk situation;
￿
Type II errors - to cause underestimates of the real risk situation.
RA provides the basis for the implementation of preventive measures. Therefore,
it can be assumed that a Type I error will result in higher protection from negative
impacts yet concurrently laying the additional burden of preventive measures on the
shipping industry. In contrast, a Type II error will result in a potentially lower degree
of protection from negative impacts with consequently a lighter burden on the ship-
ping industry.
The RA aims certainly to refl ect the real situation as accurately as possible
and implement appropriate measures in relation to the obtained results. However,
given that the ballast water issue has not been extensively researched yet in this
regard, the likelihood of error is high. In these cases the precautionary approach
should be adopted, with primary emphasis laid on the avoidance of Type II errors
through the entire RA and BWM process. In some cases Type II errors simply
cannot be prevented (e.g., sampling on-board ships, data collection with ballast
water reporting forms) and all possible measures aiming towards the error reduc-
tion have to be taken while the presence of the error has to be clearly recorded to
allow for correct RA data interpretation also for the consideration of the error
during the next step and the adoption of measures (Kirchsteiger et al. 1998 ;
Hayes 2000 ).
7 Given that the objective of RA is the prevention of undesired events via state regulation, the
'assessor' is to be understood as a state.
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