Risk Assessment in Ballast Water Management - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 145

Risk Assessment End-Point
The risk of ballast water and sediment discharges may be defi ned as the likelihood
of an undesired event to occur as a consequence of ballast discharge from a ship.
The interpretation of this defi nition entirely depends on the assessment end-point.
The end-point can be defi ned either as the discharge probability of potentially harm-
ful organisms via ballast water, or their establishment in the new environment, or
their invasiveness in and impact on the new environment.
When the identifi ed end-point is the probability of impact, 5 a risk would need to
be accurately defi ned through all RA stages from the bottom up (i.e., starting with
the introduction and establishment probability of new organisms). The RA process
was defi ned by the G7 Guidelines as “a logical process for objectively assigning the
likelihood and consequences of specifi c events, such as the entry, establishment, or
spread of harmful aquatic organisms and pathogens”. 6
The scenarios presented below describe the dependence of RA on the identifi ed
end-point under the assumption that the RA end-point is:
1. the discharge of HAOP via ballast water from a ship;
2. the establishment of HAOP in a novel environment;
3. the impact (invasiveness) of HAOP in a novel environment.
In scenario 1 the presence of HAOP in the discharged ballast water is understood
as an undesired event. In scenario 2 an undesired event is defi ned as the establish-
ment of a species, which means that the discharge of HAOP per se is not recorded
as an undesired event in cases where they remain unestablished. In scenario 3 the
undesired event is the impact while the discharge and establishment of a HAOP are
not recorded as undesired events.
After the discharge of HAOP in a new environment many of the discharged
individuals may not survive. Moreover, should they survive and establish them-
selves in the new environment, harm is not necessarily generated. However, con-
sidering the stochastic and complex array of factors which science is still unable
to predict, one of the key points is that it is extremely diffi cult or practically
impossible to conduct highly reliable assessments as to whether a new species
introduced to a novel environment will cause harm or not. There are also cases of
established of HAOP which have not caused harm for years but then, under cer-
tain circumstances, suddenly turned invasive. This lack of knowledge reveals
that the conservativeness of the approach descends from the fi rst to the third
scenario presented above as does the degree of certainty of the identifi cation of
an event.
5 i.e., various aspects of risk to human health, the natural environment, or the economy/resources.
6 G7 guidelines, paragraph 5.1.