RESIDUE
CHEMISTRY
SCIENCE
CHAPTER
EXECUTIVE
SUMMARY
Chromated
Copper
Arsenicals(
CCA)
are
registered
for
use
as
wood
preservatives.
Historically,
the
Agency
has
not
considered
wood
preservative
uses
as
food
uses.
Therefore,
there
have
been
no
dietary
exposure
considerations
for
the
registered
use
of
arsenicals
when
used
as
wood
preservatives
and
no
pesticide
tolerances
have
been
required
for
food
commodities
as
a
result
of
residues
that
could
be
incurred
as
a
result
of
these
uses.

However,
this
does
not
prevent
contact
between
residues
from
wood
treated
with
wood
preservatives
and
food
commodities.
The
Agency
is
aware
that
purchasers
of
CCA­
treated
wood
have
frequently
used
CCA­
treated
wood
in
and
around
sites
where
food
is
grown.
These
uses
could
include,
but
are
not
limited
to
the
use
of
CCA­
treated
wood;
to
outline
home
fruit
and
vegetable
gardens;
as
stakes
in
gardens
to
support
vine
crops
such
as
berries
or
grapes;
in
container
box
gardening;
and
in
the
construction
of
greenhouse
planter
boxes.
Wood
preservatives
that
are
present
in
treated
wood
that
is
used
for
theses
purposes
could
migrate
from
treated
wood
to
soil
and
be
taken
up
from
soil
by
food
commodities.

At
the
present
time,
the
Agency
and
the
wood
treatment
industry
rely
on
printed
information
and
on
tags
affixed
to
treated
wood
to
discourage
the
use
of
CCA­
treated
wood
around
food
commodities.
The
wood
treatment
industry
has
also
agreed
to
voluntarily
cancel
the
use
of
chromated
copper
arsenicals
used
to
treat
most
wood,
including
dimensional
lumber,
after
December
2003.

As
part
of
the
CCA
residue
chemistry
chapter,
the
Agency
will
include
a
discussion
of
residues
that
could
result
in
dietary
exposure
to
arsenic
and
chromium
from
the
use
of
CCA­
treated
wood
in
home
gardens.
These
home
garden
uses
of
CCA­
treated
wood
are
considered
the
most
likely
uses
that
would
contribute
arsenic
residues
to
the
human
diet.

This
chapter
will
not
include
a
discussion
of
CCA
residues
that
could
result
in
the
diet
from
other
uses
of
CCA­
treated
wood
such
as:
in
the
construction
of
fruit
and
vegetable
packing
crates;
truck
bodies;
or
underwater
fish­
farming
structures.
These
exposure
sources
are
expected
to
largely
disappear
with
the
voluntary
cancellation
of
the
use
of
CCA
to
treat
dimensional
lumber.

This
document
addresses
the
levels
of
arsenic
in
food
from
the
use
of
CCA­
treated
wood
in
situations
where
food
is
grown;
i.
e.
specifically
when
used
as
landscaping
wood
in/
around
home
gardens.
There
are
little
residue
data
available
for
arsenic
concentrations
in
food
reflecting
the
use
of
CCA­
treated
wood
used
in
raising
fruits
and
vegetables
in
gardens
outlined
with
wood,
in
containers,
in
greenhouses,
or
used
as
garden
stakes.
Likewise,
there
are
very
little
residue
data
for
chromium
residues
in
food
commodities
grown
in
the
vicinity
of
CCA­
treated
wood.

The
majority
of
residue
data
that
are
available
in
the
literature
and
from
researchers'
studies
do
not
reflect
typical
situations
for
the
use
of
treated
landscape
wood
used
to
outline
home
gardens.
The
available
arsenic
residue
data
generally
reflect
the
following
scenarios:
plants
grown
in
pots
with
soil
that
has
been
fortified
with
arsenic;
plants
grown
in
pots
with
CCA­
treated
stakes
or
wood
blocks;
or
plants
grown
in
soil
fortified
with
sawdust
from
CCA­
treated
wood.
The
data
do
tend
to
show
that
small
amounts
of
arsenic,
above
background
level,
result
in
food
grown
near
CCA­
treated
wood.
The
data
are
not
adequate
to
quantitate
arsenic
and
chromium
levels
under
typical
uses
in
which
the
bed
would
be
outlined
with
CCA­
treated
wood.
The
data
indicate
that
arsenic
levels
in
plants
appear
to
depend
on
various
factors
including
the
type
of
plant,
the
plant
part,
soil
properties,
and
distance
that
the
food
plant
is
grown
from
the
CCA­
treated
wood.
Additionally,
the
residue
data
for
both
arsenic
and
chromium
reflect
total
arsenic
levels
in
the
plants
and
do
not
differentiate
between
organic
and
inorganic
arsenic
and
do
not
determine
the
oxidation
state
of
the
two
elements.

Considering
the
above,
it
can
be
stated
that
on
a
fresh
weight
basis,
the
total
arsenic
level
in
edible
plant
parts
from
plants
grown
near
CCA­
treated
wood
is
generally
less
than
0.3
ppm.
Higher
arsenic
levels
occur
in
the
roots
and
fibrous
parts
of
the
plants(
e.
g.
up
to
1.8
ppm
in
bean
leaves
and
stems).

The
limited
residue
data
available
which
reflect
chromium
levels
in
food
commodities
grown
in
the
vicinity
of
CCA­
treated
wood
appear
to
show
little
difference
in
the
levels
of
endogenous
chromium
levels
in
the
food
plants
and
any
added
chromium
residues
from
the
CCA­
treated
wood.
However,
the
data
are
very
limited
for
purposes
of
drawing
any
conclusions.
DIETARY
EXPOSURE
CHAPTER
1.
Background
Chromated
copper
arsenate
(
CCA)­
treated
wood
is
commonly
used
by
consumers
to
outline
vegetable
gardens
and
construct
raised­
bed
gardens.
The
use
of
CCA­
treated
wood
has
been
popular
because
of
its
long
life
expectancy
due
to
its
ability
to
resist
rot,
even
in
soil.
CCAtreated
wood
is
manufactured
by
forcing
CCA
into
the
cells
of
the
wood
under
high
pressure.
Even
though
a
vacuum
carries
the
CCA
deep
into
the
cells
of
the
wood,
studies
have
shown
that
arsenic
and
chromium
from
the
CCA­
treated
wood
may
migrate
to
the
soil.
Once
in
the
soil,
arsenic
and
chromium
may
then
be
taken
up
by
edible
plants.
Thus,
the
presence
of
arsenic
and
chromium
residue
in
edible
plants
from
CCA­
treated
timber
would
be
considered
additives
to
the
naturally­
occurring
arsenic
and
chromium
already
present
in
food.
Currently,
there
are
no
registered
food
uses
for
CCA.
Few
studies
have
been
specifically
conducted
on
the
uptake
of
arsenic
and
chromium
from
CCA­
treated
wood
by
edible
plants
and
the
studies
that
are
available
show
conflicting
results.
However,
the
majority
of
the
studies,
including
the
most
recently
conducted,
show
that
very
small
amounts
of
arsenic
from
CCA­
treated
wood
are
taken
up
into
the
edible
parts
of
plants
grown
in
the
vicinity
of
CCA­
treated
wood.
The
amount
of
arsenic
taken
up
by
plants
depends
on
a
variety
of
factors
such
as
the
type
of
plant,
part
of
plant
(
i.
e.
root
vs.
above
ground),
distance
from
the
CCA­
treated
wood,
and
the
soil
properties.

2.
Results
of
CCA­
Treated
Wood
Studies
Alamgir
(
date
unknown),
Stilwell
(
2001),
Arch
Wood
Protection
(
1991),
and
Levi
(
1974)
conducted
experiments
to
study
the
uptake
of
arsenic
and/
or
chromium
in
edible
plants
using
CCA­
treated
lumber
as
the
source
of
CCA.
The
Alamgir
experiment
consisted
of
growing
plants
in
pots
of
sandy
loam
and
loamy
sand
soil
in
which
the
soil
was
obtained
from
raised
bed
gardens
at
least
ten
years
old
and
constructed
with
CCA­
treated
wood;
the
Arch
Wood
Protection
(
1991)
experiment
consisted
of
growing
plants
directly
in
raised
bed
gardens
constructed
with
Wolmanized
and
Extra
Wolmanized
brand
CCA­
treated
wood;
the
Stilwell
(
2001)
experiment
consisted
of
growing
plants
in
pots
of
soil
with
CCA­
treated
blocks
of
wood;
and
the
Levi
(
1974)
experiment
consisted
of
growing
grapes
near
wooden
stakes
treated
with
CCA.
All
of
the
experiments,
except
Levi's,
showed
small
increases
in
the
level
of
arsenic
at
varying
degrees
in
some
or
all
of
the
plants
as
compared
to
the
control
samples.
Plants
were
analyzed
for
chromium
only
in
the
studies
conducted
by
Stilwell
and
Arch
Wood
Protection.
In
these
studies,
the
concentration
of
chromium
in
the
treated
plants
did
not
vary
significantly
from
the
concentration
of
chromium
detected
in
the
control
plants.

In
the
Alamgir
study,
arsenic
was
detected
in
edible
parts
of
carrots,
spinach,
beans,
and
buckwheat
grown
in
pots
containing
soils
that
had
been
taken
at
distances
of
0
to
1
inch
away
from
the
edge
of
CCA­
treated
boards
of
vegetable
gardens.
Residue
levels
were
3
to
123
times
higher
on
a
fresh
weight
basis
than
control
samples
(
plants
grown
in
soil
obtained
from
45
to
50
inches
away
from
the
edge
of
CCA­
treated
boards
of
vegetable
gardens).
Overall,
on
a
fresh
weight
basis,
concentrations
of
arsenic
in
the
edible
parts
of
the
treated
plants
ranged
from
0.022
±
0.003
to
0.305
±
0.067
parts
per
million
(
ppm)
and
from
0.358
±
0.048
to
2.950
±
0.809
ppm
(
on
a
dry
weight
basis)
and
the
concentration
of
arsenic
in
the
control
plants
ranged
from
less
than
0.001
to
0.033
±
0.007
ppm
(
less
than
0.006
to
0.307
±
0.044
ppm
on
a
dry
weight
basis).
For
both
the
sandy
loam
and
loamy
sand
experiments,
the
highest
concentration
of
arsenic
was
detected
in
the
carrot
peel.
The
results
of
Alamgir's
study
are
shown
in
Table
1.

In
the
Stilwell
(
2001)
study,
romaine
lettuce,
grown
in
pots
with
CCA­
treated
boards
for
3
to
5
weeks,
showed
concentrations
of
arsenic
between
0.06
and
0.1
ppm
on
a
fresh
weight
basis
and
0.8
and
1.7
ppm
on
a
dry
weight
basis;
whereas
control
samples
exhibited
concentrations
of
arsenic
less
than
0.01
ppm
on
a
fresh
weight
basis
and
less
than
0.2
ppm
on
a
dry
weight
basis.

The
study
performed
by
Arch
Wood
Protection
examined
arsenic
concentrations
in
carrots,
okra,
peppers,
cucumbers,
and
tomatoes.
As
compared
to
control
samples,
the
concentrations
of
arsenic
in
carrots
were
approximately
three
times
higher
for
both
Wolmanized
and
Extra
Wolmanized
wood
(
2.9
and
2.2
ppm
versus
less
than
0.8
ppm
on
a
dry
weight
basis,
respectively).
For
okra,
arsenic
was
not
detected
in
the
control
or
Wolmanized
wood
experiment,
but
was
detected
in
the
Extra
Wolmanized
wood
experiment
at
a
concentration
of
1.5
ppm.
Similarly,
arsenic
concentrations
were
less
than
0.8
ppm
in
the
control
tomato
plants,
but
reached
concentrations
of
0.5
ppm
in
the
Wolmanized
wood
sample
and
3.7
ppm
in
the
Extra
Wolmanized
wood
sample.
For
the
pepper
and
cucumber
plants,
there
was
no
significant
difference
between
the
arsenic
levels
detected
in
the
plants
grown
in
the
CCA­
treated
garden
beds
versus
the
untreated
garden
beds.
Additionally,
there
were
no
significant
differences
in
the
concentration
of
chromium
detected
in
the
plants
grown
in
the
CCA­
treated
garden
beds
versus
the
untreated
garden
beds.
The
results
of
the
Arch
Wood
Protection
Study
are
presented
in
Table
2.

The
arsenic
levels
in
the
Arch
study
are
reported
only
on
a
dry
weight
basis.
There
are
no
information
provided
as
to
the
moisture
content
of
the
commodities.
The
arsenic
levels
for
these
commodities
would
likely
be
about
10
­
15%
of
the
dry
weight
basis,
or
about
0.3
ppm
on
a
wet
basis.

3.
Factors
Controlling
Uptake
of
CCA
by
Edible
Plants
a.
Type
and
Part
of
Plant
As
already
demonstrated
in
the
Arch
Wood
Protection
and
Alamgir
studies,
the
type
of
plant
is
a
predominate
factor
in
determining
the
amount
of
arsenic
taken
up
by
a
plant.
Additionally,
metals
typically
tend
to
concentrate
in
roots
of
plants,
especially
in
the
fibrous
parts,
with
limited
movement
to
the
edible
portions
above
ground.
However,
leafy
green
vegetables
such
as
lettuce,
spinach,
and
mustard
greens
have
also
been
shown
to
accumulate
higher
concentrations
of
metals.
As
such,
leafy
green
vegetables
and
plants
such
as
carrots,
turnips,
and
potatoes
tend
to
take
up
more
elements
from
CCA
(
Stehouwer,
2001).
In
Arch
Wood
Protection's
study,
the
highest
concentration
of
arsenic
was
detected
in
the
carrot
(
2.9
ppm
on
a
dry
weight
basis),
as
compared
to
the
okra,
pepper,
cucumber,
and
tomato
plant.
Similarly,
the
highest
concentration
of
arsenic
in
the
Alamgir
study
was
detected
in
the
carrot
peel
(
0.305
ppm
on
a
fresh
weight
basis
and
2.95
ppm
on
a
dry
weight
basis),
as
compared
to
carrots
with
peel,
carrots
without
peel,
spinach,
bean
pods,
and
buckwheat.
Typically,
metals
remain
on
the
surface
of
skin
and
can
be
removed
by
peeling
(
Lively,
1998).
In
a
study
conducted
by
Woolson
(
1973),
green
beans,
lima
beans,
spinach,
cabbage,
tomatoes,
and
radishes
were
grown
in
soil
to
which
sodium
arsenate
was
added
at
a
level
which
would
reduce
plant
growth
by
50%.
This
application
rate
was
most
likely
an
exaggerated
rate
and
the
arsenic
levels
in
the
plants
would
be
expected
to
be
high.
In
this
experiment,
the
highest
concentration
of
arsenic
was
exhibited
in
the
radish
at
a
concentration
of
approximately
8
ppm
on
a
fresh
weight
basis
(
76
ppm
on
a
dry
weight
basis),
followed
by
spinach
at
a
concentration
of
approximately
1
ppm
(
10
ppm
on
a
dry
weight
basis).
Woolson
did
not
study
the
effects
of
chromium
on
the
plants.

Speir
(
1992)
conducted
a
study
in
which
beets,
lettuce,
and
clover
were
grown
in
soil
to
which
CCA­
treated
sawdust
was
added
at
10%
(
v/
v)
volume.
In
this
study,
the
plant
tops
(
above
ground
portions)
and
roots
were
analyzed
separately
for
both
arsenic
and
chromium.
Speir
found
that
arsenic
and
chromium
did
not
accumulate
in
the
tops
of
the
plants
at
high
levels,
but
did
concentrate
in
the
fibrous
roots.
For
example,
arsenic
accumulated
in
the
aboveground
edible
parts
of
lettuce
at
concentrations
between
6
ppm
and
9
ppm
for
all
experiments
(
control
and
treated),
but
accumulated
in
the
lettuce
roots
grown
in
the
CCA
amended
soil
at
a
concentration
of
around
150
ppm
compared
to
less
than
10
ppm
in
the
controls.
Arsenic
levels
are
reported
on
a
dry
basis.

b.
Soil
Properties
Another
factor
determining
the
amount
of
arsenic
and
chromium
taken
up
by
plants
is
the
properties
of
the
soil.
In
particular,
studies
have
shown
that
uptake
by
plants
is
higher
when
plants
are
grown
in
soil
with
a
low
pH.
Arsenic,
and
especially
chromium,
are
more
soluble
and
mobile
in
soils
at
a
lower
pH.
Additionally,
the
amounts
of
arsenic
and
chromium
leached
from
wood
to
the
soil
will
increase
as
the
pH
decreases,
thus
providing
a
greater
amount
of
CCA
available
for
uptake
in
plants.
In
Speir's
study,
plants
were
grown
in
CCA
amended
soil
with
a
pH
of
5
and
a
pH
of
7.
In
general,
the
concentration
of
arsenic
and
chromium
was
greater
in
the
plants
grown
in
the
soils
with
a
pH
of
5
than
a
pH
of
7.
Additionally,
in
the
Alamgir
study,
the
higher
concentrations
of
arsenic
detected
in
the
plants
grown
in
the
loamy
sand
soil
as
compared
to
the
sandy
loam
soil
may
have
been
attributed
to
the
lower
pH
in
the
loamy
sand
soil,
as
well
as
a
higher
organic
matter
content
and
slightly
higher
concentrations
of
arsenic
in
the
loamy
sand
soil.

c.
Distance
from
CCA­
Treated
Wood
The
distance
of
the
plants
from
the
CCA­
treated
wood
may
also
determine
the
amount
of
CCA
which
will
be
taken
up
by
the
plants.
In
general,
the
concentration
of
arsenic
in
soil
will
decrease
as
the
distance
from
the
CCA­
treated
wood
increases.
For
example,
in
the
Alamgir
study,
the
arsenic
concentrations
in
the
soil
collected
from
0
to
1
inch
from
the
treated
wood
were
significantly
higher
than
soil
collected
from
45
to
50
inches
from
the
treated
wood.
The
analysis
of
the
plants
grown
in
soil
from
these
distances
also
showed
higher
concentrations
of
arsenic
in
the
plants
grown
in
soil
from
0
to
1
inch
from
the
edge
of
the
wood.
According
to
DeGroot
(
1979),
the
soil
adjacent
to
CCA­
treated
posts,
which
had
been
in
the
ground
for
30
years,
showed
increases
in
arsenic
and
chromium
within
6
inches
from
the
posts,
but
no
changes
further
away.
As
such,
it
appears
that
the
CCA
elements
which
do
leach
from
CCA­
treated
wood
do
not
migrate
far
from
the
wood.
d.
Valence
State
of
Arsenic
The
valence
state
and
form
of
arsenic
determines
the
level
of
toxicity
in
plants
and
humans.
In
general,
inorganic
arsenic
is
more
toxic
than
organic
arsenic.
The
oxidation
state
of
arsenic
was
not
determined
in
the
studies
reviewed.
Of
the
total
levels
of
arsenic
detected
in
the
plants,
much
of
the
arsenic
would
be
in
the
organic
form
(
Lively,
1998).

4.
Dietary
Risk
from
CCA­
Treated
Wood
In
general,
the
studies
reviewed
conclude
that
most
edible
plants
grown
in
gardens
constructed
with
CCA­
treated
wood
tend
to
have
a
slightly
higher
concentration
of
arsenic
in
the
plant
tissue
as
compared
to
control
samples.
For
the
most
part,
however,
the
concentrations
of
arsenic
in
the
plants
are
below
0.3
ppm
on
a
wet
basis.
In
the
studies
reviewed,
the
maximum
concentration
of
arsenic
detected
in
plants
grown
near
CCA­
treated
lumber
was
2.9
ppm
on
a
dry
weight
basis.
The
amount
of
arsenic
taken
up
by
plants
may
decrease
with
increased
distance
from
the
edge
of
the
treated
wood
and
may
be
higher
in
root
crops
(
i.
e.,
carrots
and
beets).
Limited
data
are
available
on
the
uptake
of
chromium
by
plants
from
CCA­
treated
wood.
However,
the
data
available
suggest
that
plants
grown
in
gardens
constructed
with
CCA­
treated
wood
show
no
greater
concentration
of
chromium
in
the
plant
tissue
than
plants
grown
elsewhere.
Table
1:
Concentrations
of
Arsenic
Detected
in
Plants
Grown
in
Soils
Near
CCA
Treated
Wood,
As
Determined
in
the
Alamgir,
F,
D.
Allen,
and
C.
Rosen
Study
Crop
Soil
Type
Distance
From
Treated
Wood
(
inch)
Arsenic
Concentration
(
part
per
billion)

Fresh
Weight
Basis
Dry
Weight
Basis
Carrots
(
without
peel)
Loamy
Sand
0
­
1
27
±
4
186
±
32
Loamy
Sand
45
­
50
9
±
2
55
±
7
Sandy
Loam
0
­
1
43
±
8
283
±
45
Sandy
Loam
45
­
50
5
±
2
30
±
10
Carrot
Peel
Loamy
Sand
0
­
1
165
±
15
1,633
±
169
Loamy
Sand
45
­
50
33
±
7
307
±
44
Sandy
Loam
0
­
1
305
±
67
2,950
±
809
Sandy
Loam
45
­
50
19
±
3
165
±
50
Carrots
(
with
peel)
Loamy
Sand
0
­
1
51
±
3
378
±
29
Loamy
Sand
45
­
50
14
±
2
92
±
13
Sandy
Loam
0
­
1
85
±
12
608
±
70
Sandy
Loam
45
­
50
8
±
3
49
±
10
Spinach
Loamy
Sand
0
­
1
22
±
3
358
±
48
Loamy
Sand
45
­
50
5
±
0.4
72
±
8
Sandy
Loam
0
­
1
92
±
9
1,475
±
96
Sandy
Loam
45
­
50
5
±
0.5
65
±
9
Beans
Loamy
Sand
0
­
1
38
±
21
318
±
184
Loamy
Sand
45
­
50
<
1
±
1
<
9
±
7
Sandy
Loam
0
­
1
40
±
23
360
±
204
Sandy
Loam
45
­
50
<
1
±
0.3
<
6
±
2
Beans
Leaves
and
Stems
Loamy
Sand
0
­
1
1,150
±
73
6,831
±
922
Loamy
Sand
45
­
50
113
±
12
682
±
85
Sandy
Loam
0
­
1
1846
±
130
10,894
±
1,575
Sandy
Loam
45
­
50
15
±
6
105
±
47
Buckwheat
Loamy
Sand
0
­
1
59
±
15
565
±
146
Loamy
Sand
45
­
50
7
±
0.3
54
±
4
Sandy
Loam
0
­
1
229
±
86
1,966
±
663
Sandy
Loam
45
­
50
4
±
2
37
±
13
Table
2:
Concentrations
of
Arsenic
and
Chromium
Detected
in
Plants
Grown
in
Soils
Near
CCA
Treated
Wood,
As
Determined
in
the
Arch
Wood
Protection
Study
Vegetable
Analysis,
Dry
Basis,
mg/
kg
(
ppm)

Vegetable
Untreated
Wood
Wolmanized
Wood
Extra
Wolmanized
Wood
Store
Purchase
Arsenic
Carrot
<
0.8
2.2
2.9
2.7
Okra
<
0.8
<
0.8
1.5
­­

Pepper
<
0.8
0.5
<
0.8
­­

Cucumber
0.5
<
0.9
<
0.5
­­

Tomato
<
0.8
0.5
2.1
3.7
Chromium
Carrot
3.5
1.5
1.9
1.3
Okra
1.2
1.1
0.2
­­

Pepper
0.5
0.9
0.9
­­

Cucumber
1.9
1.2
0.5
­­

Tomato
1.1
0.4
3.5
0.6
LITERATURE
SUMMARIES
Alamgir,
F.,
D.
Allen,
and
C.
Rosen,
date
unknown
This
study
assesses
the
safety
of
using
CCA­
treated
wood
vegetable
garden
beds
by
evaluating
the
distribution
of
arsenic
in
the
soil
and
the
uptake
of
arsenic
in
carrot,
spinach,
bean,
and
buckwheat
plants.
The
uptake
of
arsenic
in
plants
was
studied
by
growing
the
plants
in
pots
with
sandy
loam
and
loamy
sand
soil
in
which
the
soil
was
obtained
from
raised
bed
gardens
at
least
10
years
old
and
constructed
with
CCA­
treated
wood.
With
respect
to
the
distribution
of
arsenic
in
the
soil,
the
study
authors
concluded
the
concentration
of
arsenic
in
the
soil
is
higher
closer
to
the
wood
(
39.7
to
49.9
ppm
at
0
to
1
inch
from
the
wood)
and
decreases
further
away
from
the
wood
(<
3.1
to
10.4
ppm
at
45
to
50
inches
from
wood).
With
respect
to
the
uptake
of
arsenic
in
the
plants,
the
plants
grown
in
soil
collected
from
0
to
1
inch
away
from
the
treated
wood
exhibited
concentrations
of
arsenic
significantly
higher
than
the
plants
grown
in
soils
collected
from
45
to
50
inches
away
from
the
treated
wood
(
control
samples).
The
levels
of
arsenic
detected
in
the
edible
portions
of
the
plants
were
at
or
below
0.3
ppm2.6
ppm
on
a
fresh
weight
basis.
Of
the
edible
plant
parts,
carrot
peel
exhibited
the
highest
concentration
of
arsenic
in
both
the
sandy
loam
and
loamy
sand
soils
(
0.305
and
0.165
ppm
on
a
fresh
weight
basis,
respectively).
It
is
unlikely
that
plants
would
be
grown
in
pots
filled
with
soil
taken
from
within
1
inch
of
treated
wood.
The
exception
would
be
for
plants
grown
in
container
gardening.
Arsenic
levels
would
also
tend
to
be
higher
in
container
gardening
because
the
plant
root
system
are
confined
to
the
container
and
not
spread
into
surrounding
soil
as
would
be
the
case
for
plants
grown
in
a
garden.
Arch
Wood
Protection,
1992
This
is
an
excerpt
from
a
study
conducted
to
assess
the
uptake
of
chromium,
copper,
and
arsenic
in
vegetables
grown
in
raised
bed
gardens
constructed
with
Wolmanized
and
Extra
Wolmanized
brand
CCA­
treated
lumber.
The
vegetables
studied
were
carrots,
okra,
peppers,
cucumbers,
and
tomatoes.
The
concentration
of
copper,
chromium,
and
arsenic
in
the
vegetables
grown
in
the
raised
bed
gardens
constructed
with
Wolmanized
and
Extra
Wolmanized
CCAtreated
lumber
were
compared
to
concentrations
detected
in
the
vegetables
grown
in
raised
bed
gardens
constructed
with
untreated
lumber,
and
concentrations
in
store
bought
vegetables.
Concentrations
of
chromium
and
copper
detected
in
the
vegetables
grown
in
the
treated
beds
were
very
similar
to
the
concentrations
detected
in
vegetables
grown
in
the
control
(
untreated)
beds,
and
the
store
purchased
vegetables.
Arsenic
was
detected
in
the
carrots
and
tomatoes
grown
in
the
treated
beds
at
concentrations
slightly
higher
than
the
carrots
and
tomatoes
grown
in
the
control
beds.
However,
the
concentrations
of
arsenic
in
the
store
purchased
vegetables
were
similar
to
the
concentrations
in
the
vegetables
grown
in
the
treated
beds.

Levi,
M.
P.,
D.
Huisingh,
W.
B.
Nesbitt,
1974.

This
is
an
excerpt
from
a
study
in
which
grapes
were
analyzed
for
copper,
chromium,
and
arsenic
at
1,
2,
and
3
years
after
planting
the
grapes
three
inches
from
Southern
pine
posts
which
were
treated
with
chrome­
arsenate
or
flour­
chrome­
arsenate­
dinitrophenol.
Chromium
and
arsenic
were
not
detected
in
the
grapes
at
concentrations
above
the
limit
of
detection
(
0.2
and
0.05
ppm,
respectively).
Thus,
the
study
concluded
that
there
is
no
evidence
for
the
uptake
of
wood
preservative
components
into
leaf
tissue,
stem
tissue,
or
fruit
of
plants
grown
adjacent
to
treated
posts.

Lively,
R.,
1998
This
article
presents
information
to
help
gardeners
decide
if
pressure­
treated
wood
belongs
in
the
garden.
Specifically,
the
article
provides
data
from
a
variety
of
sources
on
leaching
of
arsenic
from
CCA­
treated
wood
into
the
soil
and
the
uptake
of
arsenic
in
vegetables.
The
article
also
provides
information
on
alternative
preservatives
which
can
be
used
to
treat
wood.

Speir,
T.
W.,
J.
A.
August,
and
C.
W.
Feltham,
1992
To
access
the
feasibility
of
using
CCA
sawdust
as
a
soil
amendment,
beetroot,
white
clover,
and
cos
lettuce
were
grown
in
soil
to
which
CCA
sawdust
was
added
at
a
10%
(
v/
v)
level.
After
the
addition
of
the
CCA
sawdust,
the
arsenic
and
chromium
contents
of
the
soil
increased
by
63
mg/
kg
and136
mg/
kg,
respectively.
As
compared
to
the
control
samples,
very
little
arsenic
and
chromium
were
taken
up
to
the
plant
tops
and
beetroot
bulbs;
however,
large
amounts
were
taken
up
in
the
fibrous
roots
of
the
plants.
Additionally,
the
uptake
of
arsenic
and
chromium
in
the
roots
and
plant
tops
was
generally
higher
at
a
pH
of
5
than
a
pH
of
7.
The
study
authors
concluded
that
the
uptake
of
arsenic
and
chromium
by
the
edible
portions
of
the
plants
are
low,
and
probably
would
be
minimal
at
a
normal
garden
pH;
however,
uptake
of
arsenic
and
chromium
by
fibrous
roots
is
a
concern.
The
study
authors
stress
that
this
study
only
evaluated
three
plant
species
and
a
wider
range
of
edible
plants
should
be
studied.
The
use
of
sawdust
from
CCA­
treated
wood
is
not
a
recommended
practice.
However,
this
practice
could
result
in
arsenic
levels
above
background
levels
in
plants.

Stehouwer,
R.,
2001
This
fact
sheet,
prepared
by
Pennsylvania
State
University,
College
of
Agricultural
Science,
Agricultural
Research
and
Cooperative
Extension,
explains
the
method
for
treating
wood,
examines
the
risks
from
gardening
with
treated
lumber,
and
makes
recommendations
for
reducing
any
possible
risks.
Specifically,
the
fact
sheet
provides
information
on
the
effects
of
arsenic,
chromium,
and
copper
on
plant
and
human
health,
the
properties
of
these
elements
in
soil
and
plants,
and
scientific
evidence
for
the
leaching
of
these
elements
from
treated
wood
and
uptake
into
plants.

Stilwell,
D.,
2001
Stilwell
conducted
experiments
using
romaine
lettuce
and
mustard
greens
grown
in
Pro
Mix
(
50%
Peat
Moss,
25%
Perlite,
25%
Vermiculite,
and
lime
to
pH
5.6)
and
sandy
loam
soil
to
which
CCA
treated
blocks
of
wood,
CCA
liquid
spikes,
or
CCA
powder
was
added.
The
plants
were
allowed
to
grow
for
3
to
5
weeks
in
pots
and
were
then
analyzed
for
copper,
chromium,
and
arsenic
by
atomic
spectroscopy.
The
results
show
that
small,
but
measurable,
increases
of
arsenic
were
detected
in
the
lettuce
grown
with
CCA
sawdust
and
CCA
treated
blocks
of
wood.
The
amount
of
arsenic
detected
in
the
mustard
plants,
which
were
only
grown
in
pots
of
soil
treated
with
liquid
CCA,
was
about
8
times
greater
than
the
amount
detected
in
the
romaine
lettuce
grown
under
the
same
conditions.
In
most
cases,
the
arsenic
level
in
the
plant
tissue
increased
as
the
concentration
of
arsenic
in
the
soil
increased.
However,
in
some
cases,
the
arsenic
level
in
the
plant
tissue
reached
a
plateau
or
saturated
region.
The
form
of
arsenic
found
was
not
known.
In
this
report,
Stilwell
also
summarizes
the
results
of
experiments
conducted
by
other
researchers
on
the
leaching
of
CCA
from
CCA­
treated
wood
to
soil
and
the
subsequent
uptake
of
CCA
in
plants.

This
study
is
intended
to
show
that
arsenic
added
to
soil
can
result
in
an
increase
in
plant
arsenic
concentrations.
The
plant
arsenic
levels
in
the
study
are
undoubtedly
higher
than
would
have
occurred
if
the
plants
had
been
grown
in
untreated
soil.

Woolson,
E.
A.
,
1973
This
study
analyzed
the
phytotoxic
response
and
crop
uptake
of
arsenate
by
six
different
vegetable
crops
on
three
soils
with
different
physical
and
chemical
characteristics.
The
soils
were
treated
with
500
ppm
of
arsenic
as
sodium
arsenate.
The
results
showed
that
the
phytotoxicity
of
arsenic
residues
was
highest
on
Lakeland
loamy
sand
and
lowest
on
Hagerstown
silty
clay
loam.
Correlations
between
available
arsenic
and
plant
dry
weight
indicated
that
green
beans
were
most
sensitive
to
arsenic.
Following
green
beans,
the
crop
sensitivity
to
arsenic
in
declining
order
was
lima
beans,
spinach,
radish,
tomato,
and
cabbage.
When
considering
the
edible
plant
parts,
radish
(
a
root
crop)
had
the
highest
arsenic
content
at
the
level
which
growth
was
reduced
by
50%
(
GR
50)
by
the
addition
of
sodium
arsenate
to
the
soil.
Spinach
had
the
next
highest
arsenic
content
at
the
GR
50
level.
The
arsenic
concentrations
in
the
radish
and
spinach
plants
at
the
GR
50
level
were
approximately
8
ppm
and
1
ppm
on
a
fresh
weight
basis,
respectively,
and
76
ppm
and
10
ppm
on
a
dry
weight
basis,
respectively.
The
soil
at
the
GR
50
level
for
radish
contained
about
19
ppm
of
available
arsenic
from
a
treatment
of
50
ppm
to
the
Hagerstown
soil
and
100
ppm
to
the
other
two
soils.
Correlation
coefficients
between
the
arsenic
and
the
edible
part
of
the
plant
were
much
lower
than
when
the
whole
plant
was
considered,
expect
for
radish,
spinach,
and
lima
beans.

LITERATURE
REFERENCES
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M.
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from
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Detected.
www.
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com/
levi.
html
