Interpreting
the
PBT
Profiler
Results
Introduction
The
PBT
Profiler
helps
to
identify
potential
persistent,
bioaccumulative,
and
toxic
(PBT)
chemicals
using
a
series
of
computer
estimation
methods
based
on
chemical
structure
and
physical/
chemical
properties.
The
PBT
Profiler
uses
the
results
of
these
estimation
methods
and
compares
the
results
to
a
set
of
well­
defined
criteria
for
each
of
these
three
areas.
For
a
chemical
to
be
considered
a
PBT,
it
must
exceed
the
criteria
in
all
3
areas;
that
is,
it
must
be
persistent,
bioaccumulative,
and
toxic.
Chemicals
that
are
persistent,
bioaccumulative,
and
toxic
are
of
concern
because
they
can
accumulate
over
time
to
higher
concentrations
that
may
adversely
impact
health
or
the
environment.

The
PBT
Profiler
has
three
levels
of
output
that
appears
on
two
separate
pages:

 
PBT
Estimate
 
Persistence,
Bioaccumulation,
and
Toxicity
results
 
P2
Considerations
The
PBT
Profiler
summary
output
and
the
individual
estimates
for
each
area
(persistence,
bioaccumulation,
and
toxicity)
are
provided
in
table
format
on
the
initial
results
screen.
Any
number
of
chemicals
can
be
profiled
and
the
results
for
all
chemicals
are
provided
on
this
page.
The
user
can
rapidly
determine
which
estimates
exceed
the
PBT
Profiler
criteria
as
they
appear
in
orange
or
red
text;
those
that
do
not
exceed
the
PBT
Profiler
criteria
appear
in
green
text.

Example
Results
Page
for
2,3,4,6­
tetrachlorophenol
Persistence
Bioaccumulation
Toxicity
58­
90­
2
Phenol,
2,
3,4,
6­
tetrachloroPBT
Profiler
Estimate
=
PBT
P2
considerations
Media
Half­
Life
(days)
Percent
in
Each
Medium
BCF
Fish
ChV
(mg/
l)

Water
60
15%
212
0.032
Soil
60
70%

Sediment
540
14%

Air
58
1%

CTD
in
air
=
875
Km
Overall
Persistence
=
115
days
(Note:
these
results
are
provided
only
as
a
representative
example,
experimental
data
are
available
for
this
chemical).

Each
of
the
important
terms
used
by
the
PBT
Profiler
are
linked
to
its
definition.
A
link
to
the
P2
Considerations
output
is
also
provided
for
each
chemical.
The
P2
Considerations
output
discusses
the
results
of
the
PBT
Profiler
on
a
chemical­
bychemical
basis
and
includes
additional
information
on
the
results
of
the
PBT
Profiler
estimates.
More
information
on
interpreting
the
results
for
each
type
of
output
is
provided
below.

Summary
Output
­
The
PBT
Profiler
Estimate
The
PBT
Profiler
summary
output
is
based
on
the
results
of
the
individual
estimates
and
it
uses
an
uppercase
P,
B,
or
T
to
represent
the
persistence,
bioaccumulation,
and
toxicity
results,
respectively.
It
compares
the
estimated
results
to
a
set
of
defined
criteria
for
each
area.
If
the
estimated
results
exceed
the
criteria
in
any
of
the
three
areas
the
corresponding
letter
is
shaded
orange
or
red;
if
the
estimate
does
not
exceed
the
criteria,
it
is
shaded
green.
In
the
black­
and­
white
version,
the
corresponding
letter
is
italicized
(
P
)
or
underlined
(
P
)
if
the
estimated
results
exceed
the
criteria
and
it
appears
in
lowercase
(
p
)
it
the
estimate
does
not
exceed
the
criteria.

For
a
chemical
to
be
considered
a
PBT,
it
must
be
persistent,
bioaccumulative,
and
toxic.
For
chemicals
run
through
the
PBT
Profiler,
the
following
examples
are
predicted
to
be
PBTs:

 
P
B
T
 
P
B
T
 
P
B
T
(or
any
other
combination
of
orange
and
red
text)

In
the
black­
and­
white
version,
The
PBT
Profiler
would
display
these
examples
as
follows:

 
P
B
T
 
P
B
T
 
P
B
T
The
following
examples
are
not
predicted
to
be
PBTs:

 
PBT
(
p
bt)
 
PBT
(
p
bT)
 
PBT
(
P
B
t
)

Reviewing
the
summary
output
allows
the
results
of
the
PBT
Profiler's
estimates
on
the
persistence,
bioacuumulation,
and
toxicity
of
a
chemical
substance
to
be
readily
determined.

Another
result
that
is
worth
noting
when
identifying
P2
opportunities
occurs
when
the
PBT
Profiler
can
not
estimate
a
chemical's
aquatic
toxicity:

 
PB
T
(
P
B
°
)
 
P
B
T
(
P
B
°
)
 
Any
combination
of
orange
or
red
P
and
B
with
a
gray
T
or
(
°
)
in
the
black­
and
white
version)

In
these
examples,
the
chemical
is
expected
to
be
persistent
and
bioaccumulative,
but
the
aquatic
toxicity
could
not
be
estimated.
Given
that
persistent
and
bioaccumulate
chemicals
may
accumulate
in
the
environment
to
relatively
high
levels,
chemicals
with
this
type
of
estimated
result
should
be
reviewed
similar
to
those
predicted
to
be
a
PBT
when
identifying
P2
opportunities.

If
a
chemical
is
expected
to
be
present
in
water,
soil,
or
sediment,
the
PBT
Profiler
then
determines
which
of
these
three
environmental
compartments
the
chemical
is
estimated
to
be
most
prevalent
in
(the
predominant
compartment).
If
the
half­
life
in
the
predominant
compartment
exceeds
the
persistence
criteria,
then
the
PBT
Profiler
will
shade
the
persistence
term
as
P
or
P
(
P
or
P
),
indicating
that
this
chemical
is
expected
to
persist
in
the
environment.
The
PBT
Profiler
does
not
explicitly
consider
a
chemical's
fate
in
air
in
the
persistence
summary
estimate
Persistence,
Bioaccumulation,
and
Toxicity
Results
The
Persistence,
Bioacummulation,
and
Toxicity
results
provide
numerical
estimates
for
indicators
in
each
of
these
three
areas
and
are
provided
in
a
tabular
format.
The
persistence
results
are
further
broken
down
to
provide
information
for
each
of
the
environmental
compartments.

Persistence
The
persistence
section
provides
the
half­
life
in
each
of
the
environmental
media
(also
called
environmental
compartments
­
air,
water,
soil,
and
sediment)
as
well
as
the
amount
(as
a
percent
of
the
total)
expected
to
be
found
in
each
compartment.
The
half­
life
indicates
how
long
(in
days)
a
chemical
is
expected
to
persist
in
each
environmental
compartment.
The
percent
in
each
medium
provides
an
estimate
of
how
much
is
found
in
each
environmental
compartment
after
its
release
(the
sum
of
the
percent
of
all
four
media
=
100%).
Using
this
information,
P2
initiatives
can
be
identified
by
comparing
the
results
to
likely
release
scenarios
throughout
the
life
cycle
of
the
substance.

The
PBT
Profiler
compares
the
half­
life
in
each
environmental
compartment
to
a
defined
set
of
persistence
criteria.
If
the
half­
life
exceeds
the
persistence
criteria,
its
value
is
shaded
orange
or
red;
if
the
criteria
are
not
exceeded,
the
half­
life
is
shaded
green.
In
the
black­
and­
white
version,
these
are
indicated
using
italics
(e.
g.,
60)
and
underlines
(e.
g.,
180)
for
those
values
that
exceed
the
PBT
Profiler
criteria.
The
persistence
criteria
in
air
differ
from
those
or
water,
soil,
and
sediment
and
the
methodology
to
determine
the
persistence
in
each
media
are
slightly
different.
When
viewing
the
persistence
results,
the
user
can
quickly
identify
which
environmental
compartments
a
chemical
may
be
persistent
in
by
noting
in
which
media
the
half­
life
has
exceeded
the
PBT
Profiler
persistence
criteria.

The
percent
in
each
medium
column
of
the
table
provides
an
indication
of
the
partitioning,
or
transport,
of
a
chemical
in
the
environment.
This
value
is
provided
to
the
user
to
help
identify
P2
initiatives
by
helping
with
possible
release
and
exposure
scenarios
as
well
as
providing
information
on
a
chemical's
likely
environmental
fate.
The
values
in
water,
soil,
and
sediment
are
used
directly
in
the
summary
persistence
estimate.
The
persistence
summary
term
is
determined
based
on
a
chemicals
half­
life
in
the
media
it
is
predominately
found
in
(excluding
air).
The
P2
Considerations
results
page
provides
narrative
that
helps
to
put
the
persistence
results
in
perspective.

The
PBT
Profiler
also
provides
two
other
estimates
that
can
be
used
to
better
understand
a
chemical's
persistence
in
the
environment.
The
characteristic
travel
distance
(CTD)
estimate
provides
an
indication
of
how
far
a
chemical
is
expected
to
travel
in
air
after
its
initial
release
to
the
environment.
This
is
an
estimate
of
its
potential
for
long­
range
transport
in
air,
which
addresses
a
chemical's
potential
for
migrating
to
remote
locations,
and,
therefore,
the
potential
for
exposure
far
from
its
original
point
of
release.
Using
published
criteria,
the
PBT
Profiler
ranks
the
CTD
as
high,
medium,
orlow
based
on
its
potential
for
long­
range
transport
in
air.
The
corresponding
highlights
in
the
black­
andwhite
version
are
underlined
(e.
g.,
2100)
and
italicized
(e.
g.,
1000),
respectively.
The
PBT
Profiler
also
estimates
an
overall
environmental
persistence
that
is
based
on
a
standardized
set
of
environmental
conditions.
This
value
provides
an
estimate
of
overall
environmental
persistence
based
only
on
reactivity
and
not
from
losses
through
irreversible
movement
of
the
chemical
in
the
environment
(such
as
when
it
is
buried
deeply
in
sediment).
The
overall
persistence
is
not
compared
to
the
PBT
Profiler
criteria
for
ranking
purposes,
however,
it
is
a
useful
value
to
determine
a
chemical's
potential
for
degradation
in
the
environment.
It
is
also
useful
for
directly
comparing
different
chemicals
when
identifying
P2
initiatives.

Bioaccumulation
The
bioaccumulation
results
provide
the
numerical
estimate
for
the
fish
bioconcentration
factor
(BCF).
The
BCF
is
a
unit­
less
value.
In
general,
compounds
that
are
found
to
bioconcentrate
are
also
found
to
bioaccumulate.
The
PBT
Profiler
compares
the
BCF
to
a
definedsetofbioaccumulation
criteria.
If
the
BCF
exceeds
the
PBT
Profiler
bioaccumulation
criteria,
its
value
is
shaded
orange
or
red;
if
the
criteria
are
not
exceeded,
it
is
shaded
green.
If
the
BCF
result
for
a
chemical
is
shaded
orange
or
red
(italicized
or
underlined
in
the
black­
and­
white
version),
the
PBT
Profiler
predicts
that
it
may
be
bioaccumulative.

Toxicity
The
aquatic
toxicity
results
provide
the
numerical
estimate
for
the
fish
Chronic
Value
(ChV)
in
mg/
l.
The
PBT
Profiler
compares
the
ChV
to
a
defined
set
of
toxicity
criteria.
If
the
ChV
exceeds
the
PBT
Profiler
toxicity
criteria,
its
value
is
shaded
orange
or
red;
if
the
criteria
are
not
exceeded,
it
is
shaded
green.
If
the
ChV
result
for
a
chemical
is
shaded
orange
or
red
(italicized
or
underlined
in
the
black­
and­
white
version),
the
PBT
Profiler
predicts
that
it
may
be
toxic.

The
PBT
Profiler
will
flag
chemicals
where
the
maximum
water
solubility
is
estimated
to
be
lower
than
the
Fish
ChV
(in
mg/
l).
This
is
referred
to
as
no
effect
at
saturation.
In
this
situation,
the
chemical
cannot
reach
a
concentration
high
enough
in
environmental
waters
to
allow
the
estimated
aquatic
toxicity
effects
to
be
expressed.
The
PBT
Profiler
results
for
chemicals
that
fall
into
this
category
should
still
be
interpreted
with
caution,
however,
especially
if
they
are
predicted
to
be
persistent
and
bioaccumulate.
The
P2
Considerations
results
page
will
help
to
put
the
results
for
chemicals
displaying
no
effect
at
saturation
into
perspective.

P2
Considerations
Results
The
P2
Considerations
Results
section,
located
on
a
separate
page
for
each
chemical,
provides
additional
information
on
the
PBT
Profiler
results
on
a
chemical­
by­
chemical
basis.
This
page
contains
information
on
how
the
summary
output
(the
PBT
Profiler
Estimate)
was
determined
as
well
as
the
meaning
of
the
individual
persistence,
bioaccumulation,
and
toxicity
results
.
The
init
ial
sect
ion
is
the
most
robust
section
of
this
report
and
contains
a
discussion
on
partitioning,
transformation,
and
persistence.
Based
on
the
chemical­
specific
results,
it
may
also
contain
information
on
pollution
prevention
considerations
that
should
be
considered.
The
initial
section
also
contains
additional
information
on
the
long­
range
transport
potential
of
the
chemical,
as
well
as
its
estimated
partitioning
based
on
a
number
of
different
release
scenarios.

The
bioconcentration
and
toxicity
sections
also
discuss
the
chemical
values
provided
on
the
results
page
and
may
provide
chemical­
specific
P2
considerations
as
appropriate.

Developed
by
the
Environmental
Science
Center
under
contract
to
the
Office
of
Pollution
Prevention
and
Toxics
,
U.
S.
Environmental
Protection
Agency
Computer
Resources
Donated
by
Syracuse
Research
Corporation
Ver
0.
911
BetaR
Restricted
Access
Last
Updated
April
18,
2001
