...
Fate
...
and
...
effect
...
of
...
contaminants
...
The
...
guideline
...
given
...
in
...
the
...
integrated
...
management
...
strategy
...
(IMS)
...
is
...
based
...
on
...
the
...
following
...
steps
...
to
...
assess
...
the
...
risks
...
caused
...
by
...
large-scale
...
groundwater
...
contamination
...
(see
...
figure
...
below).
...
- Carry
...
- out
...
- a
...
- megasite
...
- characterization
...
- Define
...
- potential
...
- risk
...
- clusters
...
- Carry
...
- out
...
- fate
...
- and
...
- transport
...
- modelling
...
- Determine
...
- risks
...
- and
...
- derive
...
- local
...
- standards
...
- Finalize
...
- risk
...
- clusters
1.
...
In
...
the
...
megasite
...
characterization,
...
all
...
information
...
relevant
...
to
...
a
...
risk
...
assessment
...
is
...
to
...
be
...
specified.
...
This
...
characterization
...
is
...
based
...
on
...
the
...
developed
...
conceptual
...
model
...
and
...
should
...
include:
...
- the
...
- contaminant
...
- situation
...
- the
...
- megasite
...
- natural
...
- systems
...
- and
...
- infrastructure
...
- the
...
- potential
...
- receptors
...
Executing
...
this
...
step
...
should
...
result
...
in
...
gathering
...
all
...
necessary
...
data
...
regarding
...
the
...
risk
...
assessment
...
and
...
storing
...
them
...
in
...
a
...
structured
...
way
...
using
...
a
...
geographical
...
information
...
system
...
(GIS).
...
2.
...
Potential
...
risk
...
clusters
...
are
...
made
...
which
...
help
...
to
...
systematically
...
structure
...
the
...
megasite.
...
Site-specific
...
conditions
...
are
...
important
...
in
...
the
...
determination
...
of
...
risk
...
clusters.
...
The
...
generic
...
aspects
...
of
...
clustering
...
are:
...
- estimation
...
- of
...
- pathway
...
- -
...
- and
...
- receptor-specific
...
- priority
...
- contaminants
...
- estimation
...
- of
...
- transfer
...
- pathways
...
- between
...
- contaminant
...
- sources
...
- and
...
- receptors
...
Once
...
the
...
potential
...
risk
...
clusters
...
have
...
been
...
selected,
...
a
...
specific
...
and
...
detailed
...
risk
...
assessment
...
for
...
potential
...
receptors
...
is
...
carried
...
out
...
in
...
the
...
following
...
steps.
...
Because
...
of
...
the
...
IMS
...
being
...
a
...
tiered
...
approach,
...
an
...
adjustment
...
of
...
the
...
potential
...
clusters
...
to
...
final
...
clusters
...
takes
...
place
...
in
...
the
...
final
...
step
...
of
...
this
...
section.
...
3.
...
The
...
fate
...
and
...
transport
...
modelling
...
is
...
carried
...
out
...
for
...
each
...
derived
...
cluster
...
and
...
each
...
potential
...
receptor
...
to
...
obtain
...
information
...
about
...
the
...
tendency
...
of
...
the
...
temporal
...
and
...
spatial
...
behaviour
...
of
...
contaminants.
...
It
...
is
...
based
...
on:
...
- criteria
...
- of
...
- the
...
- risks
...
- for
...
- potential
...
- receptors
...
- reliability
...
- of
...
- the
...
- description
...
- of
...
- groundwater
...
- and
...
- contaminant
...
- transport
...
- processes
...
The
...
reliability
...
of
...
the
...
pollutant
...
transport
...
description
...
is
...
the
...
base
...
of
...
all
...
further
...
assessments,
...
and
...
therefore
...
needs
...
to
...
be
...
discussed
...
in
...
detail.
...
The
...
IMS
...
offers
...
tools
...
for
...
making
...
the
...
choice
...
of
...
reliable
...
models
...
and
...
screening
...
methods
...
of
...
the
...
contaminant
...
situation.
...
4.
...
The
...
risks
...
have
...
to
...
be
...
determined
...
with
...
regard
...
to
...
possible
...
mitigation
...
measures
...
on
...
the
...
basis
...
of
...
the
...
modelling
...
results.
...
Tools
...
for
...
translating
...
the
...
modelling
...
results
...
into
...
risks
...
to
...
specific
...
receptors
...
of
...
concern
...
are
...
presented,
...
and
...
referred
...
to,
...
in
...
the
...
tool
...
section.
...
The
...
site-specific
...
standards
...
are
...
to
...
be
...
derived
...
as
...
a
...
result
...
of
...
the
...
risk
...
assessment,
...
depending
...
on
...
the
...
following
...
aspects:
...
- the
...
- functions
...
- of
...
- the
...
- receptors
...
- of
...
- concern
...
- the
...
- potential
...
- management
...
- scenarios
...
- (on
...
- a
...
- strategic
...
- level)
...
- the
...
- stakeholders'
...
- priority
...
- and
...
- risk
...
- perception
...
The
...
standards
...
determined
...
for
...
the
...
receptors
...
of
...
concern
...
serve
...
as
...
the
...
input
...
data
...
for
...
developing
...
and
...
optimising
...
risk
...
reduction
...
scenarios.
...
This
...
is
...
done
...
in
...
the
...
next
...
section
...
of
...
the
...
IMS.
...
5.
...
The
...
risk
...
clusters
...
must
...
be
...
finalized
...
according
...
to
...
the
...
results
...
of
...
modelling
...
and
...
risk
...
assessment.
...
An
...
adjustment
...
of
...
the
...
potential
...
clusters
...
may
...
be
...
needed
...
to
...
derive
...
the
...
final
...
clusters.
...
These
...
are
...
the
...
base
...
for
...
the
...
development
...
of
...
risk
...
reduction
...
scenarios
...
in
...
next
...
section
...
of
...
the
...
IMS.