CREOSOTE­
RESIDUE
CHEMISTRY
Background:

Creosote,
an
oil­
based
wood
preservative,
unlike
pentachlorophenol,
historically
has
not
had
agriculture
base
uses,
or
any
indirect
food
contact
uses,
and
hence
was
never
a
subject
of
FDA's
food
basket
survey.
Creosote
is
a
complex
mixture
of
aromatic/
phenolic
compounds
and
from
simple
two
ring
cyclic
organic
hydrocarbons
to
five
/
six
membered
fused
cyclic
substances.
These
polycyclic
aromatic
hydrocarbons
(
PAHs)
constitute
about
85%
of
the
total
mixture
of
creosote.
These
PAHs
range
from
being
moderately
water
soluble
(
see
product
chemistry
science
chapter)
to
being
practically
insoluble
(
chrysene,
pyrene
etc.).
In
a
1979
Document
of
the
Environmental
Protection
Agency
on
the
Water­
Related
Environmental
Fate
of
129
Priority
Pollutants
(
EPA­
440/
4­
79­
029b,
1979,
Volume
II),
the
Agency
observed:
"
­­
under
most
environmental
conditions,
the
dominant
aquatic
transport
process
for
the
polycyclic
aromatic
hydrocarbons
will
be
adsorption
onto
the
suspended
particulates.
The
role
of
volatilization
is
unknown
but
under
certain
conditions
(
e.
g.,
water
agitation)
it
could
be
competitive
with
adsorption.
The
ultimate
fate
of
naphthalene
and
possibly
other
polycyclic
aromatic
appear
to
be
biodegradable
by
microganisms
and
metabolism
(
biotransformation)
by
multi­
cellular
organisms."
No
food­
related
exposure
from
the
creosote
mixture
was
indicated
at
that
time.

The
Agency
issued
a
Position
Document
4
(
PD
4)
in
1984
on
Wood
Preservative
Pesticides
specifically
about
Creosote,
Pentachlorophenol
and
Inorganic
Arsenicals.
The
Document
stated
that
"
The
Agency
was
concerned
that
food,
feed
and
water
may
become
contaminated
from
home
and
farm
use
of
pentachlorophenol
or
creosote
products
and
that
there
could
be
direct
contact
with
domestic
animals
or
livestock."
Having
the
same
concern
in
mind
the
Agency
earlier
had
proposed
(
PD
2/
3)
to
include
the
label
amendment:
"
Do
not
use
creosote
or
pentachlorophenol
in
a
manner
which
may
result
in
direct
exposure
of
domestic
animals
or
livestock
or
in
the
contamination
of
food,
feed,
or
drinking
or
irrigation
water
(
e.
g.,
food
crates,
irrigation
flumes,
vegetable
stakes,
feed
lot
bins
and
watering
troughs."
Therefore,
in
PD
4,
the
Agency
established
the
Final
Regulatory
Position
that
all
wood
preservatives
such
as
oil­
based
creosote
must
include
the
following
information
their
product
use
labels:

"
Do
not
apply
where
there
may
be
direct
contact
with
domestic
animals
or
livestock
and
where
there
may
be
contact
with
food,
feed
or
drinking
and
irrigation
water."
The
Agency
concluded
that
this
statement
on
the
use
labels
for
creosote
application
would
eliminate
the
possibility
of
liquid
formulation
contact
with
food,
feed
or
water
during
the
pesticide
application.
(
Wood
preservative
Pesticide:
Creosote,
Pentachlorophenol
and
Inorganic
Arsenicals,
PD
4,
Office
of
Pesticides
and
Toxic
Substances,
Washington,
DC
20460,
July
1984).

There
is
no
report
of
which
shows
migration
of
creosote
or
its
components
into
ground
water.
Creosote
is
disposed
off
in
hazardous
waste
landfills
only
after
it
has
been
treated
to
EPA­
specified
standards
(
after
the
toxic
phenolic
components
have
been
eliminated).

PAHs
which
constitute
the
largest
percent
of
the
creosote
mixture
have
been
shown
to
partition
between
water,
soil
and
animals.
The
K
OC
of
some
of
the
PAHs
are
high
and
have
high
binding
constants
with
soil
and
bioaccumulation
of
some
of
these
PAHs
have
been
shown
to
take
place
with
benthic
organisms.
A
number
of
bioaccumulation
studies
have
appeared
in
the
recent
literature
and
these
indicate
that
the
PAHs
have
a
tendency
to
bioaccumulate
in
a
number
of
aquatic
organisms
as
well
as
benthic
ones.(
See
science
chapter
on
environmental
fate
of
creosote).
However,
very
few
of
these
studies
show
that
any
significant
biomagnification
in
aquatic
food
chains
take
place.
In
fact
more
studies
have
shown
that
the
some
of
PAHs
are
rapidly
metabolized
by
aquatic
organisms
and
are
thus
eliminated
from
biological
systems.
Thus
some
of
the
PAHs
components
though
present
but
not
at
high
level
in
some
of
the
human
food
items
(
aquatic),
food
chain
biomagnification
does
not
seem
to
be
of
concern
in
the
exposure
scenario.

The
use
patterns
of
creosote
do
not
apply
to
RACs,
direct
food
contact
or
indirect
food
contact
surfaces
and
hence
no
residue
chemistry
data
(
Series
860­
Residue
Chemistry
Test
Guidelines)
2
was
asked
by
the
Agency
nor
was
submitted.

The
Agency
has
no
concerns
about
residues
on
direct
food
contact,
food
contact
surfaces
and
or
biomagnification
through
trophic
transfer
at
this
time.
If
further
scientific
research
shows
a
high
degree
of
bioaccumulation
and
biomagnification
due
to
exposure
from
creosote
or
some
of
its
components,
residue
chemistry
data
may
be
required
in
the
future.
References
1.
OPPTS
Test
Guidelines;
Series
860
(
Residue
Chemistry)

2.
EPA's
Position
Document
4
(
PD
4,
July
1984,
pp
174)

3.
Water­
Related
Environmental
Fate
of
129
Priority
Pollutants,
Volume
2,
EPA
440/
4­
79­
029b,
December
1979
4.
Creosote,
Toxicological
Profile,
US
Department
of
health
&
Human
Services,
PHS,
Agency
for
Toxic
susbtances
&
Disease
Registry,
Document
TP­
90­
09,
December
1990
