Although you
probably think
you know the
answer,
scientists and
regulatory
authorities have
spent much time
and efforts to
make the concept
clear and
workable by
expert agencies,
like the EFSA in
Europe.
‘Risk’
has been defined
as a function of
the probability
of an adverse
effect and of
its severity. To
make it clear :
adverse effects
on health or the
environment
result from ‘hazards’,
which are
potentially
harmful agents (biological,
physical or
chemical). But
whether and to
what extent
these hazards
will actually
cause harm must
be approached on
probabilistic
terms : the
exposure to the
hazard and the
severity of the
effect will
finally
determine the
risk.
If we take the
example of the «
Monarch
butterfly
controversy »,
much of the
dispute was
caused by a
misunderstanding
of the notions
of risk and
hazard. In this
story, it was
proven in
laboratory
experiments that
pollen from
transgenic Bt-maize
was a hazard for
the larvae of
the Monarch
butterfly, in
the sense that
Bt toxins fed to
the larvae could
kill them. But
what is the risk
for the Monarch
butterflys in
the crop
environment ?
Further analyses
are needed for
answering the
question,
measuring the
amounts of
pollen spread in
the environment,
the presence of
the larvae at
that time,
analyzing the
feeding
behaviour of the
larvae, hence
the actual
exposure of the
insects to the
Bt-pollen, etc.
After a team of
scientists was
requested to
dissect the
problem, it was
concluded that,
although the Bt-pollen
is a hazard for
the Monarch
butterfly larvae,
the associated
risk in the crop
environment is
negligible.
