­
1
­
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
April
6,
2006
MEMORANDUM
SUBJECT:
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
Ecological
Hazard
and
Environmental
Risk
Characterization
and
Environmental
Modeling
Chapters
for
the
Reregistration
Eligibility
Decision
(
RED)
Document
(
D322613),
Edited
per
Phase
I
Error
Correction
Comments
and
Revised
ESA
Language
TO:
Kathryn
Avivah
Jakob,
Chemical
Review
Manager
Ben
Chambliss,
Team
Leader
Mark
Hartman,
Branch
Chief
Regulatory
Management
Branch
II
Antimicrobials
Division
(
7510C)

FROM:
Kathryn
Montague,
M.
S.,
Biologist/
Acting
Team
Leader
Srinivas
Gowda,
Microbiologist
Siroos
Mostaghimi,
Environmental
Engineer/
Acting
Team
Leader
Risk
Assessment
and
Science
Support
Branch
Antimicrobials
Division
(
7510C)

THRU:
Norm
Cook,
Branch
Chief
Risk
Assessment
and
Science
Support
Branch
Antimicrobials
Division
(
7510C)

Attached
are
the
TCMTB
ecological
hazard
and
environmental
risk
characterization
and
environmental
modeling
chapters
for
incorporation
into
the
RED
document.
­
2
­
ECOLOGICAL
HAZARD
AND
ENVIRONMENTAL
RISK
ASSESSMENT
CHAPTER
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)

D322613
PC
Code
035603
CASE
No.:
2625
04/
06/
2006
Kathryn
Montague
Srinivas
Gowda
Siroos
Mostaghimi
Antimicrobials
Division
Office
of
Pesticide
Programs
U.
S.
Environmental
Protection
Agency
1200
Pennsylvania
Avenue,
NW
Washington,
DC
20460
­
3
­
Table
of
Contents
I.
Executive
Summary.
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1
II.
Ecological
Hazard
Assessment.
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3
A.
Toxicity
to
Terrestrial
Animals
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3
1.
Birds,
Acute
and
Subacute
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3
2.
Birds,
Chronic.
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5
3.
Mammals,
Acute
and
Chronic
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5
B.
Toxicity
to
Aquatic
Animals
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7
1.
Freshwater.
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7
a.
Freshwater
Fish,
Acute.
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7
b.
Freshwater
Fish,
Chronic.
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8
c.
Freshwater
Invertebrates,
Acute
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d.
Freshwater
Invertebrates,
Chronic.
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10
e.
Freshwater
Field
Studies.
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6.
Estuarine
and
Marine
Organisms.
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a.
Estuarine/
Marine
Fish,
Acute.
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b.
Estuarine/
Marine
Fish,
Chronic.
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11
c.
Estuarine/
Marine
Invertebrates,
Acute.
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d.
Estuarine/
Marine
Invertebrates,
Chronic
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.11
e.
Estuarine/
Marine
Field
Studies.
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7.
Bioaccumulation
in
Aquatic
Organisms.
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12
8.
Toxicity
to
Plants
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12
III.
Environmental
Fate
and
Exposure
Assessment
Summaries.
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13
A.
Environmental
Fate
Assessment
Summary.
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B.
Environmental
Exposure
Assessment
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14
1.
Terrestrial.
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14
a.
Seed
Treatment..
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14
b.
Antisapstain
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2.
Aquatic
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15
a.
Seed
Treatment.
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15
b.
Antisapstain.
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16
IV.
Risk
Assessment
and
Risk
Characterization
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A.
Terrestrial
Organisms..
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20
B.
Aquatic
Organisms..
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C.
Endangered
Species
Considerations..
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22
D.
Label
Hazard
Statements
and
Use
Recommendations..
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V.
References
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24
Appendix
I:
Antisapstain
Environmental
Modeling..
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.28
­
4
­
I.
EXECUTIVE
SUMMARY
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
is
a
pesticide
that
is
used
as
a
seed
treatment
to
prevent
mold
and
fungus
on
cotton,
wheat,
barley,
oats,
rice,
sugar
beets,
and
safflower.
Additionally,
it
is
used
to
control
algae,
slime,
mold,
and
fungus
in
industrial
processing
waters
in
various
applications,
such
as
leather
processing,
recirculating
cooling
towers,
pulp
and
paper
mills,
storage
tanks,
secondary
oil
recovery,
and
waste
water
systems.
It
is
also
used
as
a
materials
preservative
in
various
industrial
applications.
TCMTB
is
also
used
as
a
wood
preservative,
primarily
to
control
sapstain
in
cut
lumber.

Environmental
Fate:
TCMTB
shows
pH­
dependent
hydrolytic
degradation.
While
hydrolytically
stable
at
pH
5,
the
half­
life
at
pH
9
is
1.8­
2.1
days.
TCMTB
breaks
down
rapidly
by
photolysis,
with
a
half
life
of
1.5
hours.
Biotic
degradation
also
occurs,
with
half­
lives
ranging
from
1.4
days
in
soil
under
aerobic
conditions
to
6.9
days
in
water/
sediment
systems
under
anaerobic
conditions.
TCMTB
is
mobile­
very
mobile
in
various
soils,
which
indicates
that
runoff
into
aquatic
habitats
is
a
potential
concern.

The
Kow
of
TCMTB
is
1995.
A
Kow
>
1000
indicates
that
a
chemical
may
potentially
bioconcentrate;
however,
the
results
of
a
bioconcentration
study
in
fish
indicate
that
bioconcentration
of
TCMTB
will
be
minimal.

Several
major
metabolites
are
formed
during
the
biotic
degradation
processes
of
TCMTB,
including
2­
benzothiazolesulfonic
acid
(
BTSA)
and
2­
mercaptobenzothiazole
(
2­
MBT).
BTSA
not
of
toxicological
concern
due
to
being
completely
excreted
(
sulfonic
acid)
and
having
negligible
toxicity.
2­
MBT
is
generally
less
toxic
than
parent
TCMTB
(
see
tables,
below);
therefore,
mitigation
of
any
risks
from
TCMTB
toxicity
endpoints
will
be
protective
of
any
risks
from
2­
MBT.
Therefore,
the
environmental
risk
assessment
was
conducted
for
TCMTB
only.

Ecological
Effects:
TCMTB
is
slightly
toxic
and
2­
MBT
is
practically
non­
toxic
to
birds
on
an
acute
oral
basis,
and
both
TCMTB
and
2­
MBT
are
slightly
toxic
to
birds
on
a
subacute
dietary
basis.

Based
on
the
results
of
mammalian
studies
conducted
to
meet
human
toxicity
data
requirements,
TCMTB
exhibits
low
acute
oral
and
dermal
toxicity
(
toxicity
category
III).
However,
it
is
highly
irritating
to
the
eyes
and
skin
(
toxicity
category
I
and
II,
respectively)
and
is
also
considered
to
be
highly
toxic
via
the
inhalation
route
of
exposure
(
toxicity
category
I).
TCMTB
is
a
dermal
sensitizer.
The
NOAEL
determined
in
a
rat
2­
generation
reproduction
study
was
400
ppm.

Both
TCMTB
and
2­
MBT
are
very
highly
toxic
to
freshwater
fish
on
an
acute
basis.
Chronic
testing
indicates
that
TCMTB
causes
reproduction
and
growth
effects
in
fish
at
very
low
levels
(>
0.34
ppb).
TCMTB
is
very
highly
toxic
to
estuarine/
marine
fish
on
an
acute
basis.

TCMTB
is
very
highly
toxic
and
2­
MBT
is
moderately
toxic
to
freshwater
aquatic
invertebrates
on
an
acute
basis,
and
TCMTB
also
shows
very
high
acute
toxicity
to
marine/
estuarine
­
5
­
invertebrate
species
TCMTB
impairs
growth
of
aquatic
vascular
plants
at
levels
greater
than
0.15
ppm
(
150
ppb).

Acute
risks
to
birds
and
mammals
from
consuming
TCMTB­
treated
seeds
were
below
Agency
Levels
of
Concern
(
LOCs).
Terrestrial
risk
from
the
wood
preservative
uses
of
TCMTB
were
not
addressed
due
to
a
lack
of
available
models
to
estimate
terrestrial
exposure
from
antisapstain
treatments.

Risks
to
aquatic
organisms
from
the
seed
treatment
use
of
TCMTB
are
below
LOCs.
However,
based
on
the
Tier
I
screening
model
used
for
the
antisapstain
use,
there
are
risks
to
aquatic
organisms.
Acute
LOCs
were
exceeded
for
all
taxa
except
aquatic
plants,
and
chronic
LOCs
for
fish
were
also
exceeded.
Chronic
risk
to
invertebrates
could
not
be
addressed
due
to
a
lack
of
chronic
toxicity
data.
An
environmental
monitoring
study
of
runoff
from
antisapstain
facilities
is
needed
to
address
the
potential
risks
of
concern
and
provide
estimated
environmental
concentrations
(
EEC)
to
use
in
a
refined
risk
assessment.
In
the
interim,
precautions
to
limit
leaching
and
runoff
from
antisapstain
treatment
facilities
areas
(
see
Label
Hazard
Statements
and
Use
Recommendations
section,
below)
should
prevent
exposure
to
aquatic
organisms.

Endangered
Species
Concerns:
Using
Tier
I
screening
modeling
to
assess
potential
exposure
from
antisapstain
wood
preservation
uses
of
TCMTB,
risks
to
Listed
Species
are
indicated.
Since
the
model
is
only
intended
as
a
screening­
level
model,
and,
as
such,
has
inherent
uncertainties
and
limitations
which
may
result
in
inaccurate
exposure
estimations,
further
refinement
of
the
model
is
recommended
before
any
regulatory
action
is
taken
regarding
the
antisapstain
uses
of
TCMTB.
Additionally,
impacts
from
the
antisapstain
use
could
potentially
be
mitigated
with
precautions
to
prevent
leaching
and
runoff
when
wood
is
stored
outdoors.
Due
to
these
circumstances,
the
Agency
defers
making
a
determination
for
the
antisapstain
uses
of
TCMTB
until
additional
data
and
modeling
refinements
are
available.
At
that
time,
the
environmental
exposure
assessment
of
the
antisapstain
use
of
TCMTB
will
be
revised,
and
the
risks
to
Listed
Species
will
be
reconsidered.

Data
Gaps:
Ecological
Effects:
The
following
data
requirements
are
outstanding
for
the
currently
registered
uses
of
TCMTB:
72­
4b/
850.1400
Aquatic
invertebrate
life­
cycle
study
(
wood
preservation)
123­
1/
850.4225
and
850.4250
Tier
II
seedling
emergence
and
vegetative
vigor
with
rice
(
wood
preservation)
122­
1/
850.4100
Tier
I
seedling
emergence
for
10
species
of
terrestrial
plant
(
seed
treatment)
123­
2/
850.5400Algal
Toxicity
(
wood
preservation
and
seed
treatment)
Monitoring
study
of
runoff
from
antisapstain
facilities
to
establish
EEC's
for
risk
assessment.

The
following
data
requirement
is
reserved
for
TCMTB,
pending
the
results
of
Tier
I
testing:
Tier
II
seedling
emergence
(
123­
1/
850.4100)
with
10
species
of
terrestrial
plant
(
seed
treatment)
­
6
­
Environmental
Fate:
The
following
data
requirements
are
outstanding
for
the
currently
registered
uses
of
TCMTB:
161­
1
Hydrolysis
(
wood
preservation
and
seed
treatment)
162­
1
Aerobic
soil
metabolism
(
wood
preservation
and
seed
treatment)
162­
2
Anaerobic
soil
metabolism
(
wood
preservation
and
seed
treatment)
162­
3
Aerobic
aquatic
metabolism
(
wood
preservation
and
seed
treatment)

The
following
data
requirements
are
reserved
for
TCMTB,
pending
the
results
of
lower
tier
testing
and
exposure
modeling:
164­
1
Terrestrial
field
dissipation
(
seed
treatment
and
wood
preservation)
164­
2
Aquatic
field
dissipation
(
wood
preservation)

Label
Hazard
Statements/
Use
Recommendations
The
following
ecological
effects/
environmental
risk
statements
are
required
for
TCMTB
labels:
"
This
product
is
toxic
to
fish,
aquatic
invertebrates,
oysters
and
shrimp."

"
Do
not
discharge
effluent
containing
this
product
into
lakes,
streams,
ponds,
estuaries,
oceans,
or
other
waters
unless
in
accordance
with
the
requirements
of
a
National
Pollutant
Discharge
Elimination
System
(
NPDES)
permit
and
the
permitting
authority
has
been
notified
in
writing
prior
to
discharge.
Do
not
discharge
effluent
containing
this
product
to
sewer
systems
without
previously
notifying
the
local
sewage
treatment
plant
authority.
For
guidance
contact
your
State
Water
Board
or
Regional
Office
of
the
EPA."

Antisapstain
labels
must
state:
"
Treated
lumber
must
not
be
stored
outdoors
without
precautions
to
prevent
to
prevent
leaching
by
rainfall
to
the
environment.
Suitable
precautions
include:
covering
wood
with
plastic
or
other
impervious
covering,
installation
of
berms
and
placement
of
plastic
under
the
wood
to
prevent
surface
water
runoff
away
from
the
storage
area."

II.
ECOLOGICAL
HAZARD
ASSESSMENT
A.
Toxicity
to
Terrestrial
Animals
1.
Birds,
Acute
and
Subacute
An
acute
oral
toxicity
study
using
the
technical
grade
of
the
active
ingredient
(
TGAI)
is
required
under
FIFRA
to
establish
the
toxicity
of
a
pesticide
to
birds.
The
preferred
test
species
is
either
mallard
duck
(
a
waterfowl)
or
bobwhite
quail
(
an
upland
game
bird).
The
results
of
these
studies
are
provided
in
Table
1,
below.
­
7
­
Table
1.
Acute
Oral
Toxicity
of
TCMTB
and
2­
MBT
to
Birds
Study
type
(%
a.
i.)
Species
Tested
Endpoint
Parameter
Toxicity
Value
(
95%
confidence
limits)
NOEL
Other
Effects
Noted
EPA
ID
#/
Reference
Status
TCMTB
Avian
acute
oral,
850.2100/
71­
1
(
80.4%
a.
i.)
Bobwhite
quail
(
Colinus
virginianus)
Mortality
LD50
=
660.85
(
541.09
 
805.08)
mg/
kg,
"
slightly
toxic"
<
292
mg/
kg
Signs
of
toxicity
and
reduction
of
body
weight
and
feed
consumption
at
292
mg/
kg
417809­
01
(
Campbell,
1991)
Acceptable
2­
MBT
Avian
acute
oral,
850.2100/
71­
1
(
98.22%
a.
i.)
Bobwhite
quail
(
Colinus
virginianus)
Mortality
LD50
>
2150
mg/
kg
"
practically
non­
toxic"
<
1000
mg/
kg
Some
evidence
of
dose­
related
abnormalities
upon
gross
necropsy
(
friable
livers,
resorbed
eggs,
fluid­
filled
sacs
in
abdomen)
422671­
01
(
Pedersen
and
Helsten,
1992a)
Acceptable
These
results
indicate
that
TCMTB
is
slightly
toxic
and
2­
MBT
is
practically
non­
toxic
to
birds
on
an
acute
oral
basis.
The
guideline
requirement
(
71­
1/
OPPTS
850.2100)
is
fulfilled.

Two
subacute
dietary
studies
using
the
technical
grade
of
the
active
ingredient
are
required
to
establish
the
toxicity
of
a
pesticide
to
birds.
The
preferred
test
species
are
mallard
duck
(
a
waterfowl)
and
Northern
bobwhite
quail
(
an
upland
gamebird).
Results
of
avian
subacute
dietary
tests
are
tabulated
below.

Table
2.
Avian
Subacute
Dietary
Toxicity
of
TCMTB
and
2­
MBT
Test
Type
(
Chemical
and
%
a.
i.)
Chemical
(%
a.
i.)
Species
Endpoint
Results
Other
Effects
Noted
Reference
Status
Avian
acute
dietary,
850.2200/
71­
2
TCMTB
(
80­
83%
a.
i.)
Mallard
duck
(
Anas
platyrhynchos)
Mortality
8­
day
LC50
>
10000
ppm
"
practically
non­
toxic"
Feed
consumption
and
10%
mortality
at
5,000
and
10,000
ppm
Accession
#
009869
(
Booden,
1974)
Acceptable
­
8
­
Table
2.
Avian
Subacute
Dietary
Toxicity
of
TCMTB
and
2­
MBT
Avian
acute
dietary,
850.2200/
71­
2
TCMTB
(
75
%
a.
i.)
Bobwhite
quail
(
Colinus
virginianus)
Mortality
LC50
>
10000
ppm
"
Practically
non­
toxic"
Huddling
and
depression
at
levels
>
1000
ppm
Accession
#
091624
(
Knott
and
Woodard,
1968a)
Supplemental
Avian
acute
dietary,
850.2200/
71­
2)
TCMTB
(
80%
a.
i.)
Mallard
duck
(
Anas
platyrhynchos)
Mortality
8­
day
LC50
>
4496
ppm
"
Slightly
toxic"
NOEC
<
450
ppmbased
on
reduction
in
body
weight
gain
and
food
consumption
415956­
01
(
Long
et
al.,
1990.
Acceptable
Avian
acute
dietary,
850.2200/
71­
2
TCMTB
(
80%
a.
i.)
Bobwhite
quail
(
Colinus
virginianus)
Mortality
8­
day
LC50
>
4496
ppm
"
Slightly
toxic"
NOEC
=
450
ppm,
based
on
reduction
of
average
body
weight
gain
at
higher
levels
415956­
02
(
Long
et
al.,
1990
Acceptable
Avian
acute
dietary,
850.2200/
71­
2)
2­
MBT
(
98.22%
a.
i.)
Bobwhite
quail
(
Colinus
virginianus
Mortality
8­
day
LC50
>
3387
ppm
"
Slightly
toxic"
NOEC
=
3387
ppm
 
no
signs
of
toxicity
at
any
level
424285­
01
(
Pedersen
and
Helsten,
1992b)
Acceptable
These
results
indicate
that
both
TCMTB
and
2­
MBT
are
slightly
toxic
to
birds
on
a
subacute
dietary
basis.
The
guideline
requirement
(
71­
2/
OPPTS
850.2200)
is
fulfilled.

2.
Birds,
Chronic
Avian
reproduction
studies
using
the
technical
grade
of
the
active
ingredient
are
required
for
a
pesticide
when
any
of
the
following
conditions
are
met:
(
1)
birds
may
be
subject
to
repeated
or
continuous
exposure
to
the
pesticide,
especially
preceding
or
during
the
breeding
season,
(
2)
the
pesticide
is
stable
in
the
environment
to
the
extent
that
potentially
toxic
amounts
may
persist
in
animal
feed,
(
3)
the
pesticide
is
stored
or
accumulated
in
plant
or
animal
tissues,
and/
or,
(
4)
information
derived
from
mammalian
reproduction
studies
indicates
reproduction
in
terrestrial
vertebrates
may
be
adversely
affected
by
the
anticipated
use
of
the
product.
The
currently
registered
uses
of
TCMTB
do
not
require
avian
reproduction
testing.

3.
Mammals:
(
Excerpted
from
Toxicology
Chapter)

Wild
mammal
testing
was
not
required
for
TCMTB.
In
most
cases,
rodent
acute
toxicity
values
obtained
from
studies
conducted
to
support
data
requirements
for
human
health
risk
assessment
substitute
for
wild
mammal
testing.
This
information
is
discussed
in
the
Toxicology
chapter
of
this
RED
document,
from
which
the
following
is
excerpted:
­
9
­
Table
3.
Acute
Toxicity
Data
on
TCMTB
Technical
(
80%
ai)

Guideline
No./
Study
Type
MRID
No.
Results
Toxicity
Category
870.1100
Acute
oral
toxicity
41583801
LD50
=
750
mg/
kg
(
M+
F);
80%
ai
III
870.1200
Acute
dermal
toxicity
41515401
LD50
>
2000
mg/
kg
(
M+
F);
80%
ai
III
870.1300
Acute
inhalation
toxicity
41640601
LC50=
0.07
mg/
L;
80%
ai
I
870.2400
Acute
eye
irritation
Acc
No.
111991
Diluted
Busan
72
(
60
%
ai):
primary
irritation
score
(
PIS)=
2/
110
(
slight
conjunctival
redness,
no
corneal
opacity);
undiluted
Busan
72
(
60%
ai)
PIS=
34/
110
(
blanched
conjunctivae,
chemosis,
corneal
opacity
not
reversible
by
day
7)
I
870.2500
Acute
dermal
irritation
41583701
primary
irritation
index=
7.42
with
severe
erythema
and
edema
observed
at
72
hours;
80%
ai
II
870.2600
Skin
sensitization
MRID
42349201
Acc
No.
259676
Busan
74
(
80%
ai)
caused
delayed
contact
hypersensitivity
in
guinea
pigs
when
induced
and
challenged
by
a
40%
w/
v
aqueous
concentration
of
active
ingredient.
Sensitizer.
­­

TCMTB
exhibits
low
acute
oral
and
dermal
toxicity
(
toxicity
category
III).
However,
it
is
highly
irritating
to
the
eyes
and
skin
(
toxicity
category
I
and
II,
respectively)
and
is
also
considered
to
be
highly
toxic
via
the
inhalation
route
of
exposure
(
toxicity
category
I).
TCMTB
is
a
dermal
sensitizer.

In
a
two­
generation
rat
reproduction
study,
there
were
no
treatment
related
effects
noted
at
the
highest
dose
tested
for
parental
toxicity
or
on
reproductive
parameters
examined
in
this
study.
Slight,
statistically
significant
effects
were
noted
in
mean
body
weight
in
the
high
dose
offspring
in
the
second
mating
(
F2B)
around
lactation
day
21.
This
must
be
considered
as
systemic
toxicity
as
the
litters
began
with
relatively
equal
mean
body
weights
and
around
lactation
day
14,
the
pups
began
to
consume
diet
while
continuing
to
nurse.
­
10
­
The
parental/
systemic
NOAEL
=
400
ppm
(
38.4/
45.5
mg
/
kg/
day
[
males/
females])
and
the
parental/
systemic
LOAEL
>
400
ppm
(>
38.4/
45.5
mg
/
kg/
day
[
males/
females]).
The
offspring
NOAEL
is
400
ppm.
The
Reproductive
toxicity
NOAEL
>
400ppm
and
the
Reproductive
toxicity
LOAEL
>
400
ppm.

B.
Toxicity
to
Aquatic
Animals
1.
Freshwater
a.
Freshwater
Fish,
Acute
Two
fish
toxicity
studies
using
the
TGAI
are
required
to
establish
the
toxicity
of
a
pesticide
to
freshwater
fish.
The
preferred
test
species
are
rainbow
trout
(
a
coldwater
fish)
and
bluegill
sunfish
(
a
warmwater
fish).
The
results
of
toxicity
study
are
provided
in
the
following
table.

Table
4.
Acute
Toxicity
of
TCMTB
to
Freshwater
Fish
Study
Type/%
Active
Ingredient
(
a.
i.)
Organism
Endpoints
Results
Other
Effects
Noted
Reference
Status
TCMTB
Freshwater
fish
acute
toxicity,
850.1075/
72­
1
(
90
%
a.
i.)
Rainbow
trout
(
Oncorhynchus
mykiss,
Mortality
96­
hr
static
LC50
=
55.2
(
27
 
75)
µ
g/
L
(
ppb)
"
very
highly
toxic"
None
reported
TN
2437
(
US
EPA,
1980)
Supplemental
Freshwater
fish
acute
toxicity,
850.1075/
72­
1
(
90%
a.
i.)
Bluegill
sunfish
(
Lepomis
macrochirus)
Mortality
96­
hour
static
LC50
=
32
(
16
 
45)
µ
g/
L
(
ppb)
)
"
very
highly
toxic"
None
reported
TN
2432
(
US
EPA,
1979)
Supplemental
Freshwater
fish
acute
toxicity,
850.1075/
72­
1
(
80.4
a.
i.)
Bluegill
sunfish
(
Lepomis
macrochirus
Mortality
96­
hour
flowthrough
LC50
=
8.7
µ
g/
L
(
ppb);
"
very
highly
toxic"
NOEC
=
5.1
µ
g/
L
(
ppb)
due
to
signs
of
toxicity
at
higher
levels
418042­
01
(
Machado,
1991a)
Acceptable
Freshwater
fish
acute
toxicity,
850.1075/
72­
1
(
80.4
a.
i.)
Rainbow
trout
(
Oncorhynchus
mykiss
Mortality
96­
hour
flowthrough
LC50
=
20.12
(
17.77
 
22.91)
µ
g/
L
(
ppb);
"
very
highly
toxic"
NOEC
=
8.7
µ
g/
L
(
ppb)
due
to
mortality
and
lethargy
and
loss
of
equilibrium
in
surviving
fish
at
higher
levels
418181­
01
(
Machado,
1991b)
Acceptable
­
11
­
Freshwater
fish
acute
toxicity,
850.1075/
72­
1
(
75%
a.
i.)
Rainbow
trout
(
Oncorhynchus
mykiss,
formerly
Salmo
gairdineri)
Mortality
96­
hour
static
LC50
=
29
(
21
 
40)
µ
g/
L
(
ppb);
"
very
highly
toxic"
Loss
of
equilibrium
and
lying
on
sides
observed
ACC#
091624
(
Knott
and
Woodard,
1968b)
Supplemental
Freshwater
fish
acute
toxicity,
850.1075/
72­
1
(
75%
a.
i.)
Bluegill
sunfish
(
Lepomis
macrochirus
Mortality
96­
hour
static
LC50
=
47
(
40
 
55)
µ
g/
L
(
ppb);
"
very
highly
toxic
Loss
of
equilibrium
and
lying
on
sides
observed
ACC#
091624
(
Knott
and
Woodard,
1968b)
Supplemental
2­
MBT
Freshwater
fish
acute
toxicity,
850.1075/
72­
1
(
98.22%
a.
i.)
Rainbow
trout
(
Oncorhynchus
mykiss
Mortality
96­
hour
static
LC50
=
730
µ
g/
L
(
ppb)
"
very
highly
toxic"
NOEC
=
310
µ
g/
L
(
ppb)
due
to
mortality
at
higher
treatment
levels
422322­
01
(
Collins,
1992)
Acceptable
These
results
indicate
that
both
TCMTB
and
2­
MBT
are
very
highly
toxic
to
freshwater
fish
on
an
acute
basis.
The
guideline
requirement
(
72­
1/
OPPTS
850.1075)
is
fulfilled.

b.
Freshwater
Fish,
Chronic
A
freshwater
fish
early
life­
stage
test
using
the
technical
grade
of
the
active
ingredient
is
required
for
a
pesticide
when
it
may
be
applied
directly
to
water
or
if
the
end­
use
product
is
expected
to
be
transported
to
water
from
the
intended
use
site,
and
any
of
the
following
conditions
are
met:
(
1)
the
pesticide
is
intended
for
use
such
that
its
presence
in
water
is
likely
to
be
continuous
or
recurrent
regardless
of
toxicity,
(
2)
any
aquatic
acute
LC50
or
EC50
is
less
than
1
mg/
l,
(
3)
the
EEC
in
water
is
equal
to
or
greater
than
0.01
of
any
acute
LC50
or
EC50
value,
or,
(
4)
the
actual
or
estimated
environmental
concentration
in
water
resulting
from
use
is
less
than
0.01
of
any
acute
LC50
or
EC50
value
and
any
one
of
the
following
conditions
exist:
studies
of
other
organisms
indicate
the
reproductive
physiology
of
fish
may
be
affected,
physicochemical
properties
indicate
cumulative
effects,
or
the
pesticide
is
persistent
in
water
(
e.
g.,
half­
life
greater
than
4
days).
The
preferred
test
species
is
rainbow
trout,
but
other
species
may
be
used.

Table
5:
Chronic
Toxicity
Values
for
Freshwater
Fish
Exposed
to
TCMTB
Study
Type
Species
Endpoint
NOEC
:
g
a.
i./
L
LOEC
:
g
a.
i./
L
MRID#
(
reference)
Status
Freshwater
fish
Early
life­
stage
toxicity
(
72­
4a/
850.1300)
(
83.78%
a.
i.)
Rainbow
trout
(
Oncorhynch
us
mykiss)
Reproduction
,
post­
hatch
survival,
growth
0.34
ppb
based
on
growth
and
egg
hatchability
0.56
ppb
based
on
growth
425959­
01
(
Rhodes,
1992)
Acceptable
­
12
­
The
results
indicate
that
TCMTB
causes
reproduction
and
growth
effects
in
fish
at
very
low
levels
(>
0.34
ppb).
The
guideline
requirement
(
72­
4a/
OPPTS
850.1300)
is
fulfilled.

Some
reports
in
the
published
literature
indicate
that
TCMTB
may
cause
sublethal
effects
in
fish,
which
could
result
in
an
increase
in
predation
and
a
decreased
ability
to
survive.
This
information
was
submitted
to
the
Agency
under
FIFRA
§
6(
a)
2
(
MRID
#
424053­
01).
These
studies
demonstrate
that
exposure
to
TCMTB
at
levels
of
8­
10
ppb
caused
gill
damage
and
behavioral
changes,
which
could
severely
reduce
the
ability
of
fish
to
survive
in
the
wild.
From
Proceedings
of
the
Seventeenth
Annual
Aquatic
Toxicity
Workshop,
Nov.
5­
7,
1990,
Vancouver,
BC,
Vol.
1.
(
edited
by
P.
Chapman,
F.
Bishay,
E.
Power,
K.
Hall,
L.
Harding,
D.
Mcleay,
M.
Nassichuk
and
W.
Knapp).
Canadian
Technical
report
of
Fisheries
and
Aquatic
Sciences,
No.
1774
(
vol
1).
Individual
paper
citations:
(
Kruzynski
and
Birtwell,
1990;
Kruzynski
et
al.,
1990;
Chew
et
al.,
1990).
The
LC50
used
in
this
risk
assessment
(
8.7
µ
g/
L)
is
comparable
to
the
levels
at
which
these
sublethal
effects
occurred,
however,
so
the
risk
assessment
should
be
protective
of
those
effects.

c.
Freshwater
Invertebrates,
Acute
A
freshwater
aquatic
invertebrate
toxicity
test
using
the
TGAI
is
required
to
establish
the
toxicity
of
a
pesticide
to
freshwater
aquatic
invertebrates.
The
preferred
test
species
is
Daphnia
magna.

Table
6.
Acute
Toxicity
of
TCMTB
and
2­
MBT
to
Freshwater
Invertebrates
Substance/%
Active
Ingredient
(
AI)
Organism
Endpoints
Results
Toxicity
Reference
Status
TCMTB
(
90%
a.
i.)
Daphnia
magna
Immobilization
48­
hr
static
EC50
=
23
µ
g/
L
(
ppb)
Very
highly
toxic
TN
2427
(
US
EPA,
1979)
Supple
mental
TCMTB
(
80.4%
a.
i.)
Daphnia
magna
Immobilization
48­
hour
flowthrough
EC50
=
22
µ
g/
L
(
ppb);
NOEC
=
8.7
µ
g/
L
(
ppb)
Very
highly
toxic
418382­
01
(
McNamara,
1991)
Accepta
ble
2­
MBT
2­
MBT
(
100%
a.
i.)
Daphnia
magna
Immobilization
48­
hour
static
EC50
=
2.9
mg/
L
(
ppm)
Moderatel
y
toxic
422260­
01
(
Collins,
1992b)
Accepta
ble
These
studies
indicates
that
TCMTB
is
very
highly
toxic
and
2­
MBT
is
moderately
toxic
to
aquatic
invertebrates
on
an
acute
basis.
The
guideline
requirement
(
72­
2/
OPPTS
850.1010)
is
fulfilled.

d.
Freshwater
Invertebrates,
Chronic
13
A
freshwater
aquatic
invertebrate
life­
cycle
test
using
the
technical
grade
of
the
active
ingredient
is
required
for
a
pesticide
if
the
end­
use
product
may
be
applied
directly
to
water
or
expected
to
be
transported
to
water
from
the
intended
use
site,
and
any
of
the
following
conditions
are
met:
(
1)
the
pesticide
is
intended
for
use
such
that
its
presence
in
water
is
likely
to
be
continuous
or
recurrent
regardless
of
toxicity,
(
2)
any
aquatic
acute
LC50
or
EC50
is
less
than
1
mg/
l,
or,
(
3)
the
EEC
in
water
is
equal
to
or
greater
than
0.01
of
any
acute
EC50
or
LC50
value,
or,
(
4)
the
actual
or
estimated
environmental
concentration
in
water
resulting
from
use
is
less
than
0.01
of
any
aquatic
acute
EC50
or
LC50
value
and
any
of
the
following
conditions
exist:
studies
of
other
organisms
indicate
the
reproductive
physiology
of
invertebrates
may
be
affected,
physicochemical
properties
indicate
cumulative
effects,
or
the
pesticide
is
persistent
in
water
(
e.
g.,
half­
life
greater
than
4
days).
The
preferred
test
species
is
Daphnia
magna.

One
daphnid
life­
cycle
study
was
submitted
(
MRID#
425591­
01),
but
was
invalidated
due
to
high
variablility
in
the
test
concentrations
to
which
the
daphnids
were
exposed.
A
new
daphnid
life­
cycle
study
(
72­
4b/
850.1400)
is
required
to
support
the
currently
registered
uses
of
TCMTB.

e.
Freshwater
Field
Studies
This
testing
is
currently
reserved
for
TCMTB.

6.
Toxicity
to
Estuarine
and
Marine
Organisms
a.
Estuarine
and
Marine
Fish,
Acute
Acute
toxicity
testing
with
estuarine/
marine
fish
using
the
technical
grade
of
the
active
ingredient
is
required
for
a
chemical
when
the
end­
use
product
is
intended
for
direct
application
to
the
marine/
estuarine
environment
or
the
active
ingredient
is
expected
to
reach
this
environment
because
of
its
use
in
coastal
counties.
The
preferred
test
species
is
sheepshead
minnow.

Table
7.
Acute
Toxicity
of
TCMTB
to
Estuarine/
Marine
Fish
Substance/%
a.
i.
Species
Endpoint
Results
Toxicity
Reference
Status
TCMTB
(
80%
a.
i.)
Sheepshead
minnow
(
Cyprinodon
variegatus)
Mortality
96­
hour
static
LC50
=
60
(
36
 
100)
µ
g/
L
(
ppb)
Very
highly
toxic
403636­
01
(
Surprenant,
1986a)
Accep
table
The
results
indicate
that
TCMTB
is
very
highly
toxic
to
estuarine/
marine
fish
on
an
acute
basis.
The
guideline
requirement
(
72­
3a/
OPPTS
850.1025)
is
fulfilled.

b.
Estuarine
and
Marine
Fish,
Chronic
Estuarine/
marine
fish
early
life­
stage
testing
is
not
required
for
the
currently
registered
14
uses
of
TCMTB.
The
freshwater
fish
early
life­
stage
test,
which
is
required,
should
provide
an
adequate
endpoint
for
use
in
future
risk
assessments,
since
acute
data
indicate
the
freshwater
fish
species
tested
are
comparably
sensitive
or
more
sensitive
to
TCMTB
than
the
marine/
estuarine
species
tested.
Risks
assessed
using
the
freshwater
endpoint
should
therefore
be
protective
of
marine/
estuarine
species.

c.
Estuarine
and
Marine
Invertebrates,
Acute
Acute
toxicity
testing
with
estuarine/
marine
invertebrates
using
the
technical
grade
of
the
active
ingredient
is
required
for
a
pesticide
when
the
end­
use
product
is
intended
for
direct
application
to
the
marine/
estuarine
environment
or
the
active
ingredient
is
expected
to
reach
this
environment
because
of
its
use
in
coastal
counties.
The
preferred
test
species
are
mysid
shrimp
and
eastern
oyster.

Table
8:
Acute
Toxicity
of
TCMTB
to
Estuarine/
Marine
Invertebrates
Test
%
ai.
Species
Endpoint
Results
Toxicit
y
Reference
Status
Marine/
estuarin
e
bivalve
acute
embryo­
larvae
toxicity,
72­
3b/
850.1055
80%
Quahog
clam,
Mercenari
a
mercenari
a
Normal
embryolarvae
developme
nt
48­
hour
static
EC50
=
13.9
(
9.8
 
16.1)
µ
g/
L
(
ppb)
;
NOEC
<
13
20.3
µ
g/
L
(
ppb)
Very
highly
toxic
403636­
03
(
Surprenan
t,
1986)
Acceptable
Marine/
estuarin
e
invertebrate
acute
toxicity,
72­
3c/
850.1035
80%
Mysid
(
America
mysis
bahia,
formerly
Mysidopsi
s
bahia)
Mortality
96­
hour
static
LC50
=
20.3
µ
g/
L
(
ppb);
NOEC
<
7.8
µ
g/
L
(
ppb)
Very
highly
toxic
403636­
02
(
Surprenen
t,
1987)
Acceptable
The
results
indicate
that
TCMTB
is
very
highly
toxic
to
marine/
estuarine
invertebrate
species.
The
guideline
requirements
(
72­
3b
and
72­
3c/
OPPTS
850.1035
and
850.1045)
are
fulfilled.

d.
Estuarine
and
Marine
Invertebrate,
Chronic
An
estuarine/
marine
invertebrate
life­
cycle
toxicity
test
is
required
for
a
pesticide
if
the
end­
use
product
may
be
applied
directly
to
water
or
expected
to
be
transported
to
water
from
the
intended
use
site,
and
any
of
the
following
conditions
are
met:
(
1)
the
pesticide
is
intended
for
use
such
that
its
presence
in
water
is
likely
to
be
continuous
or
recurrent
regardless
of
toxicity,
(
2)
any
aquatic
acute
LC50
or
EC50
is
less
than
1
mg/
l,
or,
(
3)
the
EEC
in
water
is
equal
to
or
greater
than
0.01
of
any
acute
EC50
or
LC50
value,
or,
(
4)
the
actual
or
estimated
environmental
concentration
in
water
resulting
from
use
is
less
than
0.01
of
any
aquatic
acute
EC50
or
LC50
value
and
any
of
the
following
conditions
exist:
studies
of
other
organisms
indicate
the
reproductive
physiology
of
invertebrates
may
be
affected,
physicochemical
properties
indicate
cumulative
effects,
or
the
pesticide
is
15
persistent
in
water
(
e.
g.,
half­
life
greater
than
4
days).
A
freshwater
invertebrate
life
cycle
study
(
72­
4b/
850.1400)
is
required
for
TCMTB.
Since
the
acute
invertebrate
data
indicate
that
daphnids
are
more
sensitive
to
TCMTB
than
clams
and
mysids,
data
from
the
freshwater
invertebrate
life
cycle
test
will
be
adequate
to
assess
risk
for
marine/
estuarine
invertebrate
species.

e.
Estuarine
and
Marine
Field
Studies
This
testing
is
currently
reserved
for
TCMTB.

7.
Bioaccumulation
in
Aquatic
Organisms
a.
Fish
(
MRID
#
424185­
01,
424932­
01,
and
467052­
01):
(
see
Environmental
Fate
chapter
of
this
RED
document
for
additional
details
regarding
this
study)

The
log
octanol­
water
coefficient
(
log
Kow)
of
TCMTB
is
3.30.
Bioconcentration
testing
is
required
for
chemicals
having
a
log
Kow
>
3.00
if
they
are
likely
to
result
in
exposure
to
aquatic
organisms,
so
this
testing
was
required
for
TCMTB.

Radiolabeled
residues
accumulated
in
bluegill
sunfish
that
were
exposed
to
uniformly
phenyl­
ring
labeled
[
14C]
TCMTB,
at
a
nominal
concentration
of
0.40
:
g/
L,
under
flowthrough
aquarium
conditions.
Maximum
bioconcentration
factors
(
BCF),
based
on
total
radioactivity
were
302X
for
viscera,
64X
for
fillet,
and
184X
for
whole
fish
tissues.
Seventy­
five
to
77%,
84­
87%,
and
84­
86%
of
the
mean
accumulated
[
14C]
residues
(
exposure
days
14­
28)
were
eliminated
from
the
fillet,
viscera
and
whole
fish
tissues,
respectively,
by
days
21­
35.

The
results
indicate
that
the
bioaccumulation
potential
of
TCMTB
is
minimal.

This
study
was
scientifically
sound,
and
fulfills
the
requirements
for
Guideline
165­
1.

8.
Toxicity
to
Plants
Phytotoxicity
testing
is
required
for
pesticides
other
than
herbicides
on
a
case­
by­
case
basis
(
e.
g.,
labeling
bears
phytotoxicity
warnings,
incidents
of
plant
damage
have
been
reported,
or
literature
indicating
phytotoxicity
is
available).
Since
many
of
the
TCMTB
product
labels
state
that
the
product
controls
algae,
semi­
aquatic
(
seed
germination
in
rice,
123­
1/
850.4225,
and
vegetative
vigor
in
rice,
123­
1/
850.4250)
and
aquatic
plant
testing
(
123­
2/
850.4400
and
850.5400)
is
required
for
TCMTB.
Additionally,
since
TCMTB
is
used
as
a
seed
treatment,
terrestrial
plant
testing
(
seed
germination,
123­
1/
850.4225
and
vegetative
vigor,
123­
1/
850.4250)
is
required
for
TCMTB.

No
terrestrial
or
semi­
aquatic
plant
toxicity
data
have
been
submitted
for
TCMTB.
These
data
are
required
to
support
the
currently
registered
uses
of
TCMTB.
Guidelines
123­
1/
850.4225
and
850.4250
(
Tier
II
seedling
emergence
and
vegetative
vigor)
for
rice
16
are
required
to
support
wood
preservative
uses.
Guideline
122­
1/
850.4100
(
Tier
I
seedling
emergence)
for
10
species
of
terrestrial
plants
(
to
support
seed
treatment
uses)
is
also
required.
Guideline
123­
1/
850.4100
(
Tier
II
seedling
emergence)
is
reserved
for
seed
treatment
uses,
pending
the
results
of
the
Tier
I
test.

A
single
aquatic
plant
study
was
submitted
for
TCMTB,
the
results
of
which
are
summarized
below.
Additional
aquatic
phytotoxicity
testing
with
four
species
of
algae
are
required
to
support
the
currently
registered
uses
of
TCMTB.

Table
9:
Toxicity
of
TCMTB
to
Aquatic
Plants
Test
Species/%
a.
i.
Endpoint
Toxicity
NOEC/
other
effects
noted
MRID
(
reference)
Status
Aquatic
Vascular
Plant
Acute
Toxicity,
Tier
II
(
doseresponse
123­
2/
850.4400
Duckweed
(
Lemna
gibba)/
83.5%
a.
i.
Frond
growth
14­
day
static
renewal
EC50
=
0.43
(
0.29
 
0.65)
mg/
L
(
ppm)
0.15
mg/
L
(
ppm)
442009­
01
(
Thompson
and
Swigert,
1996)
Acceptable
The
results
indicate
that
TCMTB
is
impairs
growth
of
aquatic
vascular
plants
at
levels
greater
than
0.15
ppm
(
150
ppb).
Guideline
850.4400
is
fulfilled;
however,
Guideline
123­
2/
850.5400
is
NOT
fulfilled,
as
additional
testing
with
four
algae
species
is
required
to
support
wood
preservative
and
seed
treatment
uses
of
TCMTB.

III.
ENVIRONMENTAL
FATE
AND
EXPOSURE
ASSESSMENT
SUMMARY
A.
Environmental
Fate
Assessment
Summary
(
excerpted
from
the
TCMTB
Environmental
Fate
Chapter
of
this
RED
document):

As
an
antimicrobial
pesticide,
2­(
thiocyanomethylthio)
benzothiazole
(
TCMTB)
is
used
largely
as
a
wood
preservative.
It
is
also
used
as
a
microbiocide/
microbiostat
and
bacteriocide/
bacteriostat
in
industrial
processes
and
water
system,
as
well
as
in
industrial
materials,
as
a
preservative.
As
an
agricultural
pesticide,
TCMB
is
used
for
seed
treatment
of
crops;
bulb
and
corm
treatment
of
flowers;
and
seed
and
soil
treatment
of
trees.
Buckman
Laboratories
has
submitted
several
guideline
studies
for
an
environmental
fate
assessment;
however,
not
all
of
these
studies
fulfill
Guidelines
requirements.
Additionally,
a
special
leaching
study
is
required
to
support
the
antisapstain
uses
of
TCMTB.
For
additional
information,
please
refer
to
the
Environmental
Fate
Chapter
of
this
RED.

An
assessment
of
the
various
studies
indicates
the
hydrolysis
of
TCMTB
is
pH
dependent.
It
is
hydrolytically
stable
under
abiotic
and
buffered
conditions
at
pH
5
and
slowly
degrades
at
pH
7.
Under
more
alkaline
conditions,
hydrolysis
proceeds
more
rapidly
with
a
calculated
half­
life
ranging
from
1.8
to
2.1
days.
Photolytically,
TCMTB
17
degrades
in
a
pH
5
buffered
aqueous
solution
with
a
calculated
half­
life
of
1.5
hours.
Based
on
its
degradation,
TCMTB
may
not
pose
a
concern
for
surface
water
run­
off.

Aquatic
metabolism
under
aerobic
and
anaerobic
conditions,
as
well
as
aerobic
soil
metabolism,
are
major
routes
of
dissipation
for
TCMTB.
TCMTB's
calculated
degradation
half­
life
in
flooded
lake
sediment
is
6.9
days;
however,
the
apparent
half­
life
occurs
between
2
and
4
days.
Similarly,
TCMTB
shows
a
tendency
of
degrading
anaerobically
in
flooded
sediment
within
2.7
days.
Under
aerobic
conditions
in
sandy
loam
soil,
a
representative
agricultural
soil,
TCMTB
degrades
with
a
calculated
half­
life
of
1.4
days.
Because
of
the
biodegradation
in
water
and
soils,
TCMTB
is
not
likely
to
contaminate
surface
and
ground
waters.

TCMTB's
tendency
to
bind
with
agricultural
soils
varies
according
to
soil
type.
TCMTB
is
very
mobile
in
clay
loam,
sand,
and
sandy
loam
soil,
and
mobile
in
clay
and
silt
loam
soil.
Kds
are
3.5
for
clay
loam
soil,
0.99
for
sand
soil,
9.9
for
sandy
loam
soil,
22.1
for
clay
soil,
and
62.7
for
silt
loam
soil.
There
may
be
a
water/
sediment
partitioning
issue
and
an
acute
adverse
impact
on
benthic
organisms.
However,
TCMTB
degrades
fairly
rapidly
in
freshwater
and
soils
and
the
impacts
may
be
short­
lived.

Additional
information
on
the
aqueous
availability
of
TCMTB
from
wood,
indicates
that
the
use
of
TCMTB
as
a
wood
preservative
may
result
in
minimal
releases
to
the
environment.
A
special
leaching
study
is
still
needed
to
address
the
leaching
from
wood
treated
with
TCMTB.

B.
Environmental
Exposure
Assessment
1.
Terrestrial:

a.
Seed
Treatment
The
Terrestrial
Residue
Exposure
Model
(
TREX)
was
used
to
calculate
risk
quotients
for
birds
and
mammals
consuming
TCMTB­
treated
seeds.
This
is
discussed
in
the
risk
assessment
section,
below.

b.
Antisapstain
No
model
is
available
to
estimate
the
exposure
to
terrestrial
wildlife
from
the
use
of
TCMTB­
treated
wood.
It
is
assumed
that
risk
to
aquatic
organisms
from
runoff
of
TCMTB
from
antisapstain
treating
facilities
is
the
greater
concern
from
this
use
of
TCMTB;
therefore,
the
risk
assessment
for
the
antisapstain
uses
of
TCMTB
focuses
on
aquatic
organisms.

2.
Aquatic:
18
a.
Seed­
Treatment
Aquatic
exposure
from
seed
treatment
uses
of
TCMTB
was
modeled
by
the
Environmental
Fate
and
Effects
Division
(
EFED)
(
USEPA,
2005).
The
following
section
is
a
summary
of
that
exposure
assessment.

This
aquatic
exposure
assessment
provides
the
estimated
environmental
concentrations
(
EEC)
for
the
use
of
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
as
a
seed
treatment
on
cotton,
wheat,
barley,
oats,
rice,
sugar
beets,
and
safflower.
For
this
action,
EFED
considered
risk
only
from
parent
compound
of
TCMTB
and
not
any
degradates
associated
with
TCMTB.

TABLE
10:
Application
Rates
for
Seed
Treatment
Uses
of
TCMTB
(
revised
02/
16/
06)
Crop
Application
Rate
(
fl
oz/
100
lbs)
Max.
Seeding
Rate
(
lbs/
ac)
Rate
(
lbs
ai/
ac)
Cotton
5
18
0.018
Safflower
2
100
0.041
Sugar
beets
2
8
0.003
Rice
1.25
150
0.039
Wheat
1.25
150
0.039
Oats
1.25
128
0.033
Barley
1.25
100
0.026
The
maximum
seeding
rate
information
is
based
on
EFED's
Terrestrial
Residue
Exposure
model
(
TREX)
(
http://
www.
epa.
gov/
oppefed1/
models/
terrestrial/).
The
application
rate
ranges
from
0.0018
lb
ai/
ac
to
0.041
lb
ai/
ac.

Modeling
Approach
For
this
aquatic
exposure
assessment,
the
highest
rate
of
0.0128
lb
ai/
ac
is
used
for
the
screening
purpose.
We
used
the
tier
1
models:
GENEEC
(
version
2.0;
Aug.
1,
2001)
and
SCI­
GROW
(
version
2.3;
Nov.
4,
2003)
screening
models
to
assess
estimated
concentrations
of
TCMTB
in
surface
water
and
ground
water,
respectively.
These
models
and
their
descriptions
are
available
at
the
EPA
internet
site:

http://
www.
epa.
gov/
oppefed1/
models/
water/
.

Conclusions:
For
surface
water
exposures,
results
from
GENEEC
indicate
that
the
TCMTB
concentrations
of
0.28
ppb
(
ug/
L),
0.26
ppb,
0.20
ppb,
0.12
ppb,
and
0.08
ppb,
respectively,
for
peak,
4­
day
average,
21­
day
average,
60­
day
average,
and
90­
day
average
exposure.
For
ground
water,
SCI­
GROW
indicates
that
TCMTB
concentrations
are
not
likely
to
exceed
0.00014
:
g/
L.
Full
model
inputs
and
outputs
are
in
provided
in
USEPA,
2006.
19
Since
these
models
are
not
specifically
designed
to
estimate
concentrations
for
pesticides
used
for
seed
treatment,
there
are
uncertainties
in
their
predictive
potential.
However,
these
uncertainties
are
not
expected
to
substantially
decrease
the
conservativeness
of
the
Tier
1
modeling
results.

Uncertainties
in
the
Seed
Treatment
Modeling
Several
factors
suggests
low
environmental
exposure
from
seed
treatment,
including
(
1)
seed
treatment
pesticides
are
applied
at
low
rates;
(
2)
adjuvants
are
used
to
encourage
pesticide
binding
to
the
seed
coat;
(
3)
physicochemical
properties
of
seed
treatment
pesticides
generally
exhibit
low
mobility
to
retain
the
pesticide
near
the
seed
coat
and
root
zone;
(
4)
seeds
are
normally
incorporated,
which
is
expected
to
limit
environmental
exposure;
and
(
5)
seed
treatments
may
have
indoor
use
patterns
(
e.
g.,
seed
storage).
In
additional
to
these
factors,
the
main
uncertainty
in
our
assessment
for
the
use
of
TCMTB
as
a
seed
treatment
is
that
we
have
not
accounted
for
the
potential
for
sorption
to,
or
reaction
on,
the
seed
coat.
Because
of
model
limitations
and
because
we
have
no
data
to
the
contrary,
we
assumed
that
TCMTB
does
not
sorb
to
the
seed
coat,
but
only
to
soil.
In
effect,
this
assumption
provides
conservative
runoff
and
leaching
scenarios.

SCI­
GROW
was
developed
using
Koc
values
ranging
from
32
 
180
ml/
g
and
half­
lives
from
13
 
1000
days.
The
input
values
for
TCMTB
are
outside
these
ranges,
therefore,
the
extrapolation
increases
the
uncertainty
of
the
ground
water
estimated
concentrations.

b.
Antisapstain
This
section
is
a
summary
of
the
environmental
exposure
modeling
conducted
to
address
the
antisapstain
uses
of
TCMTB.
For
additional
details,
please
refer
to
Appendix
I.

Runoff
concentrations
of
TCMTB
were
estimated
for
facilities
that
treat
wood
with
antisapstain
chemicals.
The
concentrations
were
estimated
using
an
approach
developed
to
determine
runoff
concentrations
of
pesticides
from
antisapstain
facilities
in
British
Columbia,
Canada
(
Krahn
and
Strub,
1990).

Krahn
and
Strub
(
1990),
in
their
protocol
for
a
leaching
study,
suggest
that
treated
wood
be
stored
outdoors,
stacked
into
lumber
packages
24"
x
48"
x
16',
and
placed
over
leachate
collection
trays
(
1.52
m
x
5.2
m).
A
total
of
16
leaching
cycles
should
be
applied
at
a
rate
of
15
mm/
day
every
other
day,
with
each
rain
duration
lasting
5
hours
and
a
target
intensity
of
3
mm/
hr.
These
values
are
based
on
the
average
precipitation
that
occurs
in
British
Columbia
in
the
worst­
case
month
of
the
year.

Predictions
of
leaching
behavior
(
as
would
be
observed
in
a
study
following
the
Krahn
and
Strub
(
1990)
protocol)
were
made
based
on
the
chemical
properties
of
TCMTB
and
a
number
of
assumptions
(
see
Antisapstain
Environmental
Modeling
Chapter
for
details).
20
Aschacher
and
Gruendlinger
(
2000)
have
measured
uptake
of
antisapstain
dipping
solution
by
pine
boards.
Freshly
sawn
pine
boards
(
2.3
x
10
x
50
cm,
code
R2
and
R2
Ab)
were
dipped
into
a
1.5%
Busan
30
L
solution
(
a.
i.:
2­
thiocyanomethylthiobenzthiazole
TCMTB).
One
set
of
samples
was
treated
in
April
1997,
and
another
set
was
treated
in
April
1998.
For
each
type
of
board
treated
each
year,
the
uptake
was
measured
based
on
the
average
of
7
boards.
The
average
uptake,
based
on
the
measurement
of
28
boards,
was
163
g
solution/
m2.
Krahn
and
Strub
(
1990)
assume
that
leachate
entering
the
storm
drain
is
diluted
with
extra
runoff
water
at
a
1:
15
ratio.
This
is
based
on
measurements
of
runoff
in
storm
drains
at
facilities
using
antisapstain
chemicals
in
British
Columbia.
Use
of
the
ratios
1:
6
and
1:
23
were
also
suggested
by
Krahn
and
Strub
(
1990)
to
determine
a
"
general
industry
wide"
predicted
runoff
concentration.
These
values
were
used
in
this
assessment.
The
estimated
leachate
concentration
(
0.196
ppm)
was
used
in
conjunction
with
these
dilution
factors
to
estimate
runoff
concentrations
Table
11.
Estimated
Runoff
Concentrations
Parameter
Dilution
Factor
Estimated
Runoff
Concentration
(
ppm)
a
High­
end
dilution
23.0
0.00852
Typical
dilution
15.0
0.0131
Low­
end
dilution
6.00
0.0327
aEstimated
Runoff
Concentration
=
Estimated
Leachate
Concentration
(
0.196
ppm)
/
Dilution
Factor
Uncertainties
and
Limitations
 
Krahn
and
Strub
(
1990)
note
that
the
concentrations
of
antisapstain
chemical
in
runoff
will
be
affected
by
numerous
variables,
including:
chemical
formulation,
chemical
retention
in
wood,
rough
vs.
planed
lumber
cut,
lumber
packaging
and
stacking,
drying
time
prior
to
exposure
to
precipitation,
precipitation
duration,
precipitation
intensity,
precipitation
frequency,
precipitation
pH,
quantity
of
treated
lumber
on
the
storage
site,
species
of
lumber
treated,
general
house
keeping
practices,
whether
the
lumber
is
1st,
2nd,
or
3rd
growth,
solubility
of
the
chemical
in
water,
diffusion
of
the
chemical
into
the
wood,
additives
in
the
formulations,
exposure
and
degradation
due
to
ultraviolet
light,
microbial
action,
ambient
temperatures,
and
affinity
of
the
chemical
to
soils
and
to
yard
surfaces.
 
Information
regarding
the
leaching
behavior
of
TCMTB­
treated
wood
is
limited.
It
is
unclear
how
well
the
method
used
above
predicts
the
results
of
a
study
conducted
using
the
protocol
described
by
Krahn
and
Strub
(
1990).
 
It
was
assumed,
for
this
assessment,
that
rain
events
are
of
equal
intensity
and
duration.
Variations
in
the
intensities
and
durations
of
rain
events
would
affect
the
results.
 
Krahn
and
Strub
(
1990)
obtained
a
dilution
factor
of
15
based
on
a
study
of
antisapstain
facilities
in
British
Columbia.
The
dilution
factor
is
dependent
on
the
intensity
of
rainfall
events.
There
is
no
reason
to
expect
that
the
average
rainfall
intensity
in
British
Columbia
would
be
representative
of
the
average
rainfall
intensity
of
the
United
States;
however,
for
lack
of
better
data,
the
value
was
used.
21
 
Krahn
and
Strub
(
1990)
assume
that
any
batch
of
treated
wood
remains
in
the
yard
for
16
rain
cycles.
The
frequency
of
rainfall
events
in
British
Columbia
may
not
be
representative
of
the
frequency
of
rainfall
events
in
the
United
States;
therefore,
the
use
of
16
rain
cycles
may
not
be
an
accurate
description
of
treatment
facilities
in
the
United
States.
 
The
model
is
sensitive
to
the
selection
of
the
thickness
of
the
leachable
region,
and
the
depth
to
which
the
antisapstain
is
assumed
to
penetrate.
Although
the
value
of
0.01
m
is
based
on
the
value
used
in
the
Wood
Leaching
Model
(
WLM)
(
Lee,
2004),
it
is
unclear
how
this
value
was
derived
and
if
use
of
the
value
is
reasonable
for
a
dipping
treatment.
The
WLM
is
still
under
development,
and
has
not
yet
been
validated.

IV.
Risk
Assessment
and
Characterization
Risk
assessment
integrates
the
results
of
the
exposure
and
ecotoxicity
data
to
evaluate
the
likelihood
of
adverse
ecological
effects.
One
method
of
integrating
the
results
of
exposure
and
ecotoxicity
data
is
called
the
quotient
method.
For
this
method,
risk
quotients
(
RQs)
are
calculated
by
dividing
exposure
estimates
by
ecotoxicity
values,
both
acute
and
chronic:

RQ
=
EXPOSURE/
TOXICITY
RQs
are
then
compared
to
levels
of
concern
(
LOCs).
These
LOCs
are
criteria
used
by
OPP
to
indicate
potential
risk
to
nontarget
organisms
and
the
need
to
consider
regulatory
action.
The
criteria
indicate
that
a
pesticide
used
as
directed
has
the
potential
to
cause
adverse
effects
on
nontarget
organisms.
LOCs
currently
address
the
following
risk
presumption
categories:
(
1)
acute
high
­
potential
for
acute
risk
is
high
regulatory
action
may
be
warranted
in
addition
to
restricted
use
classification;
(
2)
acute
restricted
use
­
the
potential
for
acute
risk
is
high,
but
this
may
be
mitigated
through
restricted
use
classification;
(
3)
acute
endangered
species
­
the
potential
for
acute
risk
to
endangered
species
is
high,
and
regulatory
action
may
be
warranted,
and
(
4)
chronic
risk
­
the
potential
for
chronic
risk
is
high,
and
regulatory
action
may
be
warranted.
Currently,
AD
does
not
perform
assessments
for
chronic
risk
to
plants,
acute
or
chronic
risks
to
nontarget
insects,
or
chronic
risk
from
granular/
bait
formulations
to
mammalian
or
avian
species.

The
ecotoxicity
test
values
(
i.
e.,
measurement
endpoints)
used
in
the
acute
and
chronic
risk
quotients
are
derived
from
the
results
of
required
studies.
Examples
of
ecotoxicity
values
derived
from
the
results
of
short­
term
laboratory
studies
that
assess
acute
effects
are:
(
1)
LC50
(
fish
and
birds)
(
2)
LD50
(
birds
and
mammals
(
3)
EC50
(
aquatic
plants
and
aquatic
invertebrates)
and
(
4)
EC25
(
terrestrial
plants).
The
NOEC
value
is
used
as
the
ecotoxicity
test
value
in
assessing
chronic
effects.

Risk
presumptions,
along
with
the
corresponding
RQs
and
LOCs
are
tabulated
below.
22
Risk
Presumptions
for
Terrestrial
Animals
Risk
Presumption
RQ
LOC
Birds
and
Wild
Mammals
Acute
High
Risk
EEC1/
LC50
or
LD50/
sqft2
or
LD50/
day3
0.5
Acute
Restricted
Use
EEC/
LC50
or
LD50/
sqft
or
LD50/
day
(
or
LD50
<
50
mg/
kg)
0.2
Acute
Endangered
Species
EEC/
LC50
or
LD50/
sqft
or
LD50/
day
0.1
Chronic
Risk
EEC/
NOEC
1
1
abbreviation
for
Estimated
Environmental
Concentration
(
ppm)
on
avian/
mammalian
food
items
2
mg/
ft2
3
mg
of
toxicant
consumed/
day
LD50
*
wt.
of
bird
LD50
*
wt.
of
bird
Risk
Presumptions
for
Aquatic
Animals
Risk
Presumption
RQ
LOC
Acute
High
Risk
EEC1/
LC50
or
EC50
0.5
Acute
Restricted
Use
EEC/
LC50
or
EC50
0.1
Acute
Endangered
Species
EEC/
LC50
or
EC50
0.05
Chronic
Risk
EEC/
MATC
or
NOEC
1
1
EEC
=
(
ppm
or
ppb)
in
water
Risk
Presumptions
for
Plants
Risk
Presumption
RQ
LOC
Terrestrial
and
Semi­
Aquatic
Plants
Acute
High
Risk
EEC1/
EC25
1
Acute
Endangered
Species
EEC/
EC05
or
NOEC
1
Aquatic
Plants
Acute
High
Risk
EEC2/
EC50
1
Acute
Endangered
Species
EEC/
EC05
or
NOEC
1
1
EEC
=
lbs
ai/
A
2
EEC
=
(
ppb/
ppm)
in
water
A.
Environmental
Risk
Assessment
for
Terrestrial
Organisms:
23
Modeling
was
performed
to
address
the
exposure
and
risk
to
birds
and
mammals
consuming
seeds
treated
with
TCMTB.
Using
the
Terrestrial
Residue
Exposure
Model
(
TREX)
(
http://
www.
epa.
gov/
oppefed1/
models/
terrestrial/)
for
the
seed
treatment
on
safflower,
which
has
the
highest
application
rate
of
0.041
lb
ai/
A,
the
following
RQs
for
seed
treatment
were
calculated:

Avian:
:
0.02
as
(
mg
ai/
kg/
day)/
LD50
The
avian
RQ
was
calculated
with
no
toxicity
scaling
factor.
Scaling
factors
are
used
when
it
is
likely
that
a
pesticide
will
be
proportionally
more
toxic
to
smaller
organisms
than
larger
ones
(
e.
g.,
the
toxicity
will
not
be
directly
correlated
with
body
weight).
TREX
recommends
a
default
scaling
factor
of
1.15,
based
on
Mineau
et
al.
(
1996);
however,
that
scaling
factor
was
developed
based
on
37
conventional
pesticides,
most
of
which
are
cholinesterase
inhibitors.
There
is
no
information
available
indicating
that
such
an
adjustment
is
necessary
or
appropriate
for
TCMTB.

Mammalian
Acute:
0.05
as
(
mg
ai/
kg/
day)/
LD50,
0.02
as
(
mg
ai/
ft2)/(
LD50*
BW)
Chronic:
0.53
as
(
mg/
kg
seed)/
reproduction
NOAEC
All
of
these
are
below
any
LOCs
for
avian
or
mammalian
acute
risk
and
mammalian
chronic
risk.
Avian
chronic
data
are
not
available
nor
required
for
the
currently
registered
uses
of
TCMTB,
therefore
chronic
avian
risk
was
not
assessed.

B.
Environmental
Risk
Assessment
for
Aquatic
Organisms:

To
develop
RQs,
the
EECs
determined
by
modeling
were
compared
to
the
most­
sensitive
endpoint
for
each
taxa.
For
seed
treatment,
the
peak
EEC
was
used
for
acute
and
endangered
species
risks,
the
21­
day
average
was
used
for
invertebrate
chronic
risk,
and
the
60
day
average
was
used
for
the
fish
chronic
risk.
For
antisapstain
uses,
the
worstcase
scenario
(
low
dilution)
and
the
"
best­
case"
(
high
dilution)
EECs
were
used
for
acute
and
endangered
species
risks,
and
the
typical
dilution
was
used
for
fish
and
invertebrate
chronic
risks.
RQs
exceeding
one
or
more
LOCs
(
listed
in
the
risk
presumptions
section,
above)
are
in
bold
text.

Table
12:
Aquatic
Organism
Risk
Quotients
for
Seed
Treatment
and
Antisapstain
Uses
of
TCMTB
Taxa/
Endpoint
Seed
treatment
EEC
Seed
Treatment
RQ
Antisapstain
EEC
Low
dilution
High
dilution
Antisapstain
RQ
Freshwater
fish
Acute
8.7
µ
g/
L
0.28
ppb
0.03
32.7
ppb
8.5
ppb
3.76
0.98
Freshwater
Invertebrates
Acute
22
µ
g/
L
0.28
ppb
0.01
32.7
ppb
8.5
ppb
1.49
0.39
Marine/
Estuarine
Fish
0.28
ppb
0.00
32.7
ppb
0.54
24
Acute
60
µ
g/
L
8.5
ppb
0.14
Marine/
Estuarine
Bivalve
Acute
13.9
µ
g/
L
0.28
ppb
0.02
32.7
ppb
8.5
ppb
2.35
0.61
Marine/
Estuarine
Invertebrate
Acute
20.3
µ
g/
L
0.28
ppb
0.01
32.7
ppb
8.5
ppb
1.61
0.42
Green
Algae
Acute
EC50
430
µ
g/
L
0.28
ppb
0.00
32.7
ppb
8.5
ppb
0.08
0.02
Green
Algae
NOEC
150
µ
g/
L
0.28
ppb
0.00
32.7
ppb
8.5
ppb
0.22
0.06
Fish
Chronic
0.34
µ
g/
L
0.12
ppb
0.35
13.1
ppb
8.5
ppb
38.53
25.00
Invertebrate
Chronic
 
DATA
GAP
0.20
ppb
­­­­­
13.1
ppb
­­­­­

For
seed
treatment,
no
LOCs
are
exceeded,
indicating
that
the
use
poses
minimal
risk
to
aquatic
organisms.

For
the
antisapstain
use,
the
low
dilution
(
worst­
case)
EECs
exceed
acute
high
risk
LOCs
for
all
taxa,
and
chronic
risk
to
fish.
Even
using
the
high
dilution
("
best­
case")
EECs
still
results
in
exceedance
of
acute
high
risk
LOCs
for
freshwater
fish
and
marine
bivalves,
and
restricted
use
LOCs
for
freshwater
invertebrates,
marine
fish
and
marine
invertebrates,
and
chronic
risk
to
fish.

Chronic
risk
to
invertebrates
cannot
be
assessed
at
this
time
due
to
the
lack
of
chronic
invertebrate
toxicity
data.

The
model
used
to
estimate
exposure
from
antisapstain
uses
is
intended
as
a
Tier
I
screening
model,
and,
as
such,
has
inherent
assumptions
and
uncertainties
that
may
result
in
over­
or
under­
estimation
of
exposure
levels.
Additional
information,
including,
but
not
limited
to,
specific
leaching
data
for
TCMTB
used
as
an
antisapstain
wood
preservative,
would
remove
some
of
the
uncertainties,
and
may
result
in
more
accurate
exposure
estimation.
An
environmental
monitoring
study
is
also
needed
to
address
the
potential
risks
of
concern
and
provide
EECs
for
a
refined
risk
assessment.

Methods
to
reduce
the
amount
of
TCMTB
potentially
released
from
antisapstain­
treated
wood
would
mitigate
the
risks.
Possible
mitigation
methods
might
include
lowering
the
application
rate
or
requiring
specific
storage
conditions
to
prevent
exposure
of
recently
treated
wood
to
weather
(
e.
g.,
full
covering)
and/
or
prevent
the
release
of
any
associated
runoff
into
aquatic
habitats
(
e.
g.,
drip
pads).
TCMTB
is
very
mobile
in
soils,
so
any
TCMTB
leached
outdoors
will
likely
reach
aquatic
habitats.

C.
Endangered
Species
Considerations
Section
7
of
the
Endangered
Species
Act,
16
U.
S.
C.
Section
1536(
a)(
2),
requires
all
federal
agencies
to
consult
with
the
National
Marine
Fisheries
Service
(
NMFS)
for
marine
and
anadromous
listed
species,
or
the
United
States
Fish
and
Wildlife
Services
(
FWS)
for
listed
wildlife
and
freshwater
organisms,
if
they
are
proposing
an
"
action"
that
25
may
affect
listed
species
or
their
designated
habitat.
Each
federal
agency
is
required
under
the
Act
to
insure
that
any
action
they
authorize,
fund,
or
carry
out
is
not
likely
to
jeopardize
the
continued
existence
of
a
listed
species
or
result
in
the
destruction
or
adverse
modification
of
designated
critical
habitat.
To
jeopardize
the
continued
existence
of
a
listed
species
means
"
to
engage
in
an
action
that
reasonably
would
be
expected,
directly
or
indirectly,
to
reduce
appreciably
the
likelihood
of
both
the
survival
and
recovery
of
a
listed
species
in
the
wild
by
reducing
the
reproduction,
numbers,
or
distribution
of
the
species."
50
C.
F.
R.
'
402.02.

To
facilitate
compliance
with
the
requirements
of
the
Endangered
Species
Act
subsection
(
a)(
2)
the
Environmental
Protection
Agency,
Office
of
Pesticide
Programs
has
established
procedures
to
evaluate
whether
a
proposed
registration
action
may
directly
or
indirectly
reduce
appreciably
the
likelihood
of
both
the
survival
and
recovery
of
a
listed
species
in
the
wild
by
reducing
the
reproduction,
numbers,
or
distribution
of
any
listed
species
(
U.
S.
EPA
2004).
After
the
Agency=
s
screening­
level
risk
assessment
is
performed,
if
any
of
the
Agency=
s
Listed
Species
LOC
Criteria
are
exceeded
for
either
direct
or
indirect
effects,
a
determination
is
made
to
identify
if
any
listed
or
candidate
species
may
co­
occur
in
the
area
of
the
proposed
pesticide
use.
If
determined
that
listed
or
candidate
species
may
be
present
in
the
proposed
use
areas,
further
biological
assessment
is
undertaken.
The
extent
to
which
listed
species
may
be
at
risk
then
determines
the
need
for
the
development
of
a
more
comprehensive
consultation
package
as
required
by
the
Endangered
Species
Act.

Using
Tier
I
screening
modeling
to
assess
potential
exposure
from
antisapstain
wood
preservation
uses
of
TCMTB,
risks
to
Listed
Species
are
indicated.
Since
the
model
is
only
intended
as
a
screening­
level
model,
and,
as
such,
has
inherent
uncertainties
and
limitations
which
may
result
in
inaccurate
exposure
estimations,
further
refinement
of
the
model
is
recommended
before
any
regulatory
action
is
taken
regarding
the
antisapstain
uses
of
TCMTB.
An
environmental
monitoring
study
of
runoff
from
antisapstain
treatment
facilities
is
needed
to
address
the
potential
risks
and
to
provide
EECs
for
use
in
a
refined
risk
assessment.
Additionally,
impacts
from
the
antisapstain
use
could
potentially
be
mitigated
with
precautions
to
prevent
leaching
and
runoff
when
wood
is
stored
outdoors.
Due
to
these
circumstances,
the
Agency
defers
making
a
determination
for
the
antisapstain
uses
of
TCMTB
until
additional
data
and
modeling
refinements
are
available.
At
that
time,
the
environmental
exposure
assessment
of
the
antisapstain
use
of
TCMTB
will
be
revised,
and
the
risks
to
Listed
Species
will
be
reconsidered.

D.
Label
Hazard
Statements
for
and
Use
Recommendations:

TCMTB
labels
must
state:

"
This
product
is
toxic
to
fish,
aquatic
invertebrates,
oysters
and
shrimp."
26
"
Do
not
discharge
effluent
containing
this
product
into
lakes,
streams,
ponds,
estuaries,
oceans,
or
other
waters
unless
in
accordance
with
the
requirements
of
a
National
Pollutant
Discharge
Elimination
System
(
NPDES)
permit
and
the
permitting
authority
has
been
notified
in
writing
prior
to
discharge.
Do
not
discharge
effluent
containing
this
product
to
sewer
systems
without
previously
notifying
the
local
sewage
treatment
plant
authority.
For
guidance
contact
your
State
Water
Board
or
Regional
Office
of
the
EPA."

Antisapstain
labels
must
state:
"
Treated
lumber
must
not
be
stored
outdoors
without
precautions
to
prevent
to
prevent
leaching
by
rainfall
to
the
environment.
Suitable
precautions
include:
covering
wood
with
plastic
or
other
impervious
covering,
installation
of
berms
and
placement
of
plastic
under
the
wood
to
prevent
surface
water
runoff
away
from
the
storage
area."
27
REFERENCES
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Studies:

Accession
#
009869.
Booden,
R.
M.
1974.
Avian
Dietary
LC50,
Mallard
Duck,
Report
#
4043620.
Unpublished
data,
conducted
by
Warf
Institute
for
Buckman
Laboratories,
Memphis,
TN.

Accession
#
091624.
Knott,
W.
B.,
and
G.
Woodard.
1968a.
Busan
72
 
Safety
Evaluation
on
Bobwhite
Quail.
Unpublished
data,
conducted
by
Woodard
Research
Corp.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN.

Accession
#
091624.
Knott,
W.
B.,
and
G.
Woodard.
1968b.
Busan
72
 
Safety
Evaluation
on
Bluegill
Sunfish
and
Rainbow
Trout.
Unpublished
data,
conducted
by
Woodard
Research
Corp.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN
MRID
#
403636­
01.
Surprenant,
D.
C.
1986a.
Acute
Toxicity
of
TCMTB
to
the
Sheepshead
Minnow,
Cyprinodon
variegatus.
Unpublished
data,
conducted
by
Springborn
Bionomics,
Inc.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN
MRID
#
403363­
02.
Surprenant,
D.
C.
1987.
Acute
Toxicity
of
TCMTB
to
Mysid
Shrimp
(
Mysidopsis
bahia).
Unpublished
data,
conducted
by
Springborn
Bionomics,
Inc.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN.

MRID
#
403636­
03.
Surprenant,
D.
C.
1986b.
Acute
Toxicity
of
TCMTB
to
Embryo­
Larvae
of
the
Quahog
Clam
(
Mercenaria
mercenaria).
Unpublished
data,
conducted
by
Springborn
Bionomics,
Inc.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN.

MRID
#
415956­
01.
Long,
R.
D.,
C.
P.
Driscoll,
K.
A.
Hoxter,
and
G.
J.
Smith.
1990.
TCMTB:
A
Dietary
LC50
Study
with
the
Mallard.
Unpublished
data,
conducted
by
Wildlife
International,
Ltd.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN.

MRID
#
415956­
02.
Long,
R.
D.,
C.
P.
Driscoll,
K.
A.
Hoxter,
and
G.
J.
Smith.
1990.
TCMTB:
A
Dietary
LC50
Study
with
the
Northern
Bobwhite.
Unpublished
data,
conducted
by
Wildlife
International,
Ltd.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN.

MRID
#
417809­
01.
Campbell,
S.
1991.
TCMTB:
An
Acute
Oral
Toxicity
Study
with
the
Northern
Bobwhite."
Unpublished
data,
conducted
by
Wildlife
International,
Ltd.,
for
Buckman
Laboratories,
Memphis,
TN
MRID
#
418042­
01.
Machado,
M.
W.
1991a.
TCMTB
 
Acute
Toxicity
to
Bluegill
Sunfish
(
Lepomis
macrochirus)
under
Flow­
through
Conditions.
Unpublished
data,
conducted
by
Springborn
Laboratories,
Inc.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN.

MRID
#
418181­
01.
Machado,
M.
W.
1991b.
TCMTB
 
Acute
Toxicity
to
Rainbow
Trout
(
Oncorhynchus
mykiss)
under
Flow­
through
Conditions.
Unpublished
data,
conducted
by
28
Springborn
Laboratories,
Inc.,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN
MRID
#
418382­
01.
McNamara,
P.
C.
1991.
TCMTB
 
Acute
Toxicity
to
Daphnids
(
Daphnia
magna)
Under
Flow­
Through
Conditions.
Unpublished
data,
conducted
by
Springborn
Laboratories,
Inc,
for
Buckman
Laboratories,
Inc.,
Memphis,
TN.

MRID
#
422260­
01.
Collins,
M.
K.
1992b.
2­
Mercaptobenzothiazole
(
ROKON)
 
Acute
Toxicity
to
Daphnids
(
Daphnia
magna)
Under
Static
Conditions.
Unpublished
data,
conducted
by
Springborn
Laboratories,
Inc.,
for
R.
T.
Vanderbilt
Ct.,
Inc.,
Norwalk,
CT.

MRID
#
422322­
01.
Collins,
M.
K.
1992a.
2­
Mercaptobenzothiazole
(
ROKON)
 
Acute
Toxicity
to
Rainbow
Trout
(
Oncorhynchus
mykiss)
Under
Static
Conditions.
Unpublished
data,
conducted
by
Springborn
Laboratories,
Inc.,
for
R.
T.
Vanderbilt
Ct.,
Inc.,
Norwalk,
CT
MRID
#
422671­
01.
Pedersen,
C.
A.,
and
B.
R.
Helsten.
1992a.
2­
Mercaptobensothiazole
(
ROKON):
14­
day
Acute
Oral
LD50
Study
in
Bobwhite
Quail.
Unpublished
data,
conducted
by
Bio­
Life
Associates,
Ltd.,
for
R.
T.
Vanderbilt
Co.,
Inc.,
Norwalk,
CT.

MRID
#
424285­
01.
Pedersen,
C.
A.,
and
B.
R.
Helsten.
1992b.
2­
Mercaptobenziothiazol
(
ROKON):
8­
Day
Acute
Dietary
LC50
Study
in
Bobwhite
Quail.
Unpublished
data,
conducted
by
Bio­
Life
Associates,
Ltd.,
for
R.
T.
Vanderbilt
Co.,
Norwalk,
CT.

MRID
#
425929­
01.
Rhodes,
J.
E.
1992.
Early
Life­
Stage
Toxicity
of
2­
(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
to
the
Rainbow
Trout
Under
Flow­
Through
Conditions.
Unpublished
data,
conducted
b
ABC
Laboratories,
Inc.,
for
Buckman
Laboratories
International,
Inc.,
Memphis,
TN.

MRID
#
442009­
01.
Thompson,
S.
G.,
and
J.
P.
Swigert.
1996.
TCMTB:
A
14­
Day
Static­
Renewal
Toxicity
Test
with
Duckweed
(
Lemna
gibba).
Unpublished
data,
conducted
by
Wildlife
International,
Ltd.,
for
Buckman
Laboratories
International,
Inc.,
Memphis,
TN.

Additional
References:

Aschacher
G
and
Gruendlinger
R,
2000.
Methods
to
evaluate
the
ecotoxicological
risks
of
antisapstain
preservatives.
Holzforschung,
Austria
Research
and
Development.
www.
holzforschung.
at/
english/
img_
eng/
ascha200.
pdf.

Addinsoft,
2004.
XLSTAT
v7.5.
http://
www.
xlstat.
com.

Chew,
G.
L.,
G.
M.
Kruzynski,
and
I.
K.
Birtwell.
Behavioural
assessment
of
exposure
of
juvenile
Chinook
salmon
(
Oncorhynchus
tshawtscha)
to
sublethal
doses
of
a
toxicant.
In
Proceedings
of
the
Seventeenth
Annual
Aquatic
Toxicity
Workshop,
Nov.
5­
7,
1990,
Vancouver,
BC,
Vol.
1.
(
edited
by
P.
Chapman,
F.
Bishay,
E.
Power,
K.
Hall,
L.
Harding,
D.
Mcleay,
M.
Nassichuk
and
W.
Knapp).
Canadian
Technical
report
of
Fisheries
and
Aquatic
Sciences,
No.
1774
(
vol
1).
29
Karickhoff
SW,
DS
Brown,
TA
Scott,
1979.
Sorption
of
Hydrophobic
Pollutants
on
Natural
Sediments.
Water
Resources.
13:
241­
248.

Krahn
P
and
Strub
R,
1990.
Standard
Leaching
Test
for
Antisapstain
Chemicals:
Regional
Program
Report
90­
10.
Environment
Canada,
Conservation
and
Protection,
Pacific
and
Yukon
Region
North
Vancouver,
BC.

Kruzynski,
G.
M.,
and
I.
K.
Birtwell.
1990.
Some
Respiratory
Responses
of
Juvenile
Pacific
Salmon
to
the
Antisapstain
Chemical
TCMTB.
In
Proceedings
of
the
Seventeenth
Annual
Aquatic
Toxicity
Workshop,
Nov.
5­
7,
1990,
Vancouver,
BC,
Vol.
1.
(
edited
by
P.
Chapman,
F.
Bishay,
E.
Power,
K.
Hall,
L.
Harding,
D.
Mcleay,
M.
Nassichuk
and
W.
Knapp).
Canadian
Technical
report
of
Fisheries
and
Aquatic
Sciences,
No.
1774
(
vol
1).

Kruzynski,
G.
M.,
I.
K.
Birtwell,
G.
L.
Chew,
G.
E.
Piercey,
and
S.
Spohn.
1990.
An
approach
to
testing
for
ecological
relevance
using
behavioral
toxicology.
In
Proceedings
of
the
Seventeenth
Annual
Aquatic
Toxicity
Workshop,
Nov.
5­
7,
1990,
Vancouver,
BC,
Vol.
1.
(
edited
by
P.
Chapman,
F.
Bishay,
E.
Power,
K.
Hall,
L.
Harding,
D.
Mcleay,
M.
Nassichuk
and
W.
Knapp).
Canadian
Technical
report
of
Fisheries
and
Aquatic
Sciences,
No.
1774
(
vol
1).

Lee
R,
2004.
WLM
recommendation
regarding
chemical
generalization.
Memorandum
to
Siroos
Mostaghimi,
USEPA.
December
15,
2004.

Mineau,
P.,
B.
T.
Collins,
and
A.
Baril.
1996.
On
the
Use
of
Scaling
Factors
to
Improve
Interspecies
Extrapolation
of
Acute
Toxicity
in
Birds.
Regul
Toxicol
Pharmacol
24;
24­
29.

USEPA.
2006.
Office
of
Pesticide
Programs
internal
memorandum,
"
Aquatic
Exposure
Assessment
for
the
Use
of
the
Fungicide
of
2­
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
as
a
Seed
Treatment
on
Cotton,
Wheat,
Barley,
Oats,
Rice,
Sugar
Beets,
and
Safflower,"
February
16,
2006.

USEPA.
2004.
Overview
of
the
Ecological
Risk
Assessment
Process
in
the
Office
of
Pesticide
Programs
U.
S.
Environmental
Protection
Agency
­
Endangered
and
Threatened
Species
Effects
Determinations,
1/
23/
04.

US
EPA.
1979.
TN
2432.
Biological
Report
of
Analysis,
90+
TCMTB,
sample
MB618.
Unpublished
data,
performed
by
US
EPA
Terrestrial
and
Aquatic
Biology
Laboratory.

US
EPA.
1979.
TN
2427.
Biological
Report
of
Analysis,
90+
TCMTB,
sample
MB618.
Unpublished
data,
performed
by
US
EPA
Terrestrial
and
Aquatic
Biology
Laboratory.

US
EPA.
1980.
TN
2437.
Biological
Report
of
Analysis,
90+
TCMTB,
sample
MB618.
Unpublished
data,
performed
by
US
EPA
Terrestrial
and
Aquatic
Biology
Laboratory.
30
USEPA,
2004.
Wood
Leaching
Model:
Chemical
Concentration
Screening
Tool,
v1.0.
USEPA/
OPPT/
AD,
developed
by
Versar,
Inc.
Appendix
I:

2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)

Antisapstain
Environmental
Modeling
Chapter
For
the
Reregistration
Eligibility
Decision
Document
33
Introduction
In
this
report,
runoff
concentrations
of
TCMTB
were
estimated
for
facilities
that
treat
wood
with
antisapstain
chemicals.
The
concentrations
were
estimated
using
an
approach
developed
to
determine
runoff
concentrations
of
pesticides
from
antisapstain
facilities
in
British
Columbia,
Canada
(
Krahn
and
Strub,
1990).
Krahn
and
Strub
used
the
following
equation
to
determine
leaching
behavior
for
a
rainfall
event:

D
C
C
leachate
runoff
=
Eq.
1
where:

Crunoff
=
Concentration
of
chemical
in
runoff
from
the
facility
(
ppm)
Cleachate
=
Concentration
of
chemical
in
leachate
(
i.
e.,
the
rainwater
dripping
directly
off
the
wood
(
ppm)
D
=
Dilution
Factor
(
unitless)

Use
of
this
equation
implies
that
the
leachate
concentration
is
directly
proportional
to
the
runoff
concentration,
regardless
of
the
rainfall
intensity
or
duration.
The
methods
for
determining
Cleachate
and
D
are
discussed
below.
The
following
general
assumptions
were
made
in
estimating
Crunoff:

 
Softwood
lumber
is
being
treated
at
the
facility
using
the
methods
described
in
the
product
labels.
 
Precipitation
in
British
Columbia
is
similar
to
that
experienced
in
the
United
States.
 
Krahn
and
Strub
(
1990)
measured
the
dilution
rates
of
runoff
at
a
British
Columbian
antisapstain
facility.
It
is
assumed
that
these
dilution
rates
are
similar
to
the
rates
for
facilities
in
the
United
States.

Concentration
of
Leachate
(
Cleachate)

Krahn
and
Strub
(
1990)
suggest
calculating
the
leachate
concentration
using
the
following
equation:

 
=
=
16
1
16
i
i
leachate
C
C
Eq.
2
where:

Cleachate
=
Concentration
of
chemical
in
leachate
(
ppm)
Ci
=
Concentration
from
a
leaching
study
associated
with
leaching
cycle
i.

Use
of
this
equation
implies:
34
 
The
lumber
yard
consists
of
wood
of
various
ages.
For
any
given
storage
yard,
the
inventory
can
be
split
into
16
sections.
Prior
to
any
rain
event,
1/
16th
of
the
yard
inventory
has
never
been
exposed
to
rain,
1/
16th
of
the
yard
inventory
has
been
exposed
to
1
rain
event,
1/
16th
of
the
yard
inventory
has
been
exposed
to
2
rain
events,
etc.
 
Leaching
data
are
available
for
a
given
chemical.
Krahn
and
Strub
(
1990)
describe
a
study
protocol
that
can
be
used
to
obtain
such
data,
and
it
is
assumed
that
the
leachate
concentrations
that
can
be
generated
using
the
Krahn
and
Strub
protocol
would
work
in
conjunction
with
Equation
2
to
give
a
reliable
estimate
of
Cleachate.

Krahn
and
Strub
(
1990),
in
their
protocol
for
a
leaching
study,
suggest
that
treated
wood
be
stored
outdoors,
stacked
into
lumber
packages
24"
x
48"
x
16',
and
placed
over
leachate
collection
trays
(
1.52
m
x
5.2
m).
A
total
of
16
leaching
cycles
should
be
applied
at
a
rate
of
15
mm/
day
every
other
day,
with
each
rain
duration
lasting
5
hours
and
a
target
intensity
of
3
mm/
hr.
These
values
are
based
on
the
average
precipitation
that
occurs
in
British
Columbia
in
the
worst­
case
month
of
the
year.

No
leaching
studies
were
available
for
TCMTB.
For
lack
of
better
data,
predictions
of
leaching
behavior
(
as
would
be
observed
in
a
study
following
the
Krahn
and
Strub
(
1990)
protocol)
were
made
based
on
the
chemical
properties
of
TCMTB
and
a
number
of
assumptions.

Lee
(
2004)
states
a
method
for
determining,
for
screening­
level
purposes,
the
quantity
of
chemical
leaching
from
pressure
treated
wood
during
rain
events.
The
following
equations
describe
the
leaching
behavior:

OC
wood
leachate
K
t
C
t
C
)
(
)
(
=
Eq.
3
kt
oe
M
t
M
 
=
)
(
Eq.
4
Z
K
SA
I
SA
k
OC
total
top
=
Eq.
5
where:

Cleachate(
t)
=
Concentration
of
chemical
in
leachate
at
time
t
(
mg/
m3)
Cwood(
t)
=
Concentration
of
chemical
in
leachable
portion
of
wood
at
time
t
(
mg/
m3)
Mo
=
Mass
of
chemical
applied
to
leachable
portion
of
wood
(
mg)
at
time
t=
0
M(
t)
=
Mass
of
chemical
remaining
in
wood
(
mg)
at
time
t
k
=
Rate
constant
(
hr­
1)
SAtop
=
Surface
area
from
bird's
eye
view
of
the
wood
(
m2)
SAtotal
=
Surface
area
exposed
to
rain
(
i.
e.,
all
surfaces
except
bottom)
35
I
=
Rainfall
Intensity
(
m/
hr)
KOC
=
Organic
carbon
partition
coefficient
(
unitless)
Z
=
Distance
from
surface
of
wood
at
which
chemical
is
available
for
leaching
(
0.01
m)

In
using
Equations
3,
4,
and
5,
the
following
assumptions
apply:

 
The
`
leachable'
portion
of
the
wood
consists
of
the
surfaces
of
the
lumber
pile
that
are
exposed
to
rain
(
surface
thickness=
Z).
The
leachable
portion
of
the
wood
at
any
given
time
is
homogenous 
i.
e.,
the
concentration
of
the
chemical
throughout
the
leachable
portion
of
the
wood
is
the
same
at
any
given
time
t.
Cwood(
t),
Mo,
and
M(
t)
all
refer
to
the
leachable
portion
of
wood
only.
 
The
value
of
Z
(
0.01
m)
is
based
on
the
default
value
presented
in
the
Wood
Leaching
Model
(
USEPA,
2005).
 
Equation
3
implies
that
a
partitioning
equilibrium
is
always
reached
between
rain
water
and
treated
wood
surfaces
after
rain
travels
from
the
top
to
the
base
of
the
wood.
Assuming
that
a
partitioning
equilibrium
model
is
reasonable
for
the
situation,
this
should
provide
an
upper
bound
estimate
for
the
amount
of
chemical
that
can
leach
from
the
wood.
 
Equations
4
and
5
imply
that
the
concentration
of
chemical
present
in
the
leachable
portion
of
the
wood
follows
first­
order
kinetics.
The
assumption
follows
from
Equation
3,
and
its
derivation
is
shown
in
Lee
(
2004).
 
Each
cycle,
as
defined
by
Krahn
and
Strub
(
1990),
is
assumed
to
correspond
to
a
5­
hour
period
of
leaching.
Therefore,
16
cycles
of
leaching
corresponds
to
80
(
i.
e.,
16x5)
hours
of
leaching.

Equations
3,
4,
and
5
can
be
modified
to
determine
Ci
(
the
average
concentration
associated
with
leaching
cycle
i,
as
shown
in
Equation
2):

leachate
i
i
i
V
t
M
t
M
C
)
(
)
(
1
 
=
 
Eq.
6
or
  
  
 

  
  
 

 
×
=
 

  

 

 

  
 
 

 

  
 

 

  
 
 
 
i
OC
total
top
i
OC
total
top
t
Z
K
SA
I
SA
t
Z
K
SA
I
SA
leachate
o
i
e
e
V
M
C
1
Eq.
7
where:

ti
=
Time
at
which
leaching
cycle
i
ends,
in
hours
(
each
leaching
cycle
is
5
hours)
Vleachate
=
Volume
of
leachate
associated
with
one
lumber
pile
(
L)
36
A
number
of
parameters
are
needed
for
use
of
Equation
7.
Table
1
shows
the
calculations
of
some
of
these
values.
The
octanol­
water
partition
coefficient
(
KOW)
was
estimated
using
KOWWIN
v1.67
(
SRC,
2004),
a
program
that
uses
the
chemical
structure
to
estimate
certain
properties
(
see
Appendix
A).
KOC
was
then
estimated
using
a
formula
found
in
Karickhoff
et
al.
(
1979).

Table
1.
Miscellaneous
Calculations
for
Leaching
Studies
Parameter
Value
Rationale
Dimensions
of
Wood
in
Krahn
and
Strub
0.61
m
x
1.22
m
x
4.88
m
per
lumber
package
(
width,
height,
length)
Krahn
and
Strub
(
1990)

Surface
area
of
Leachable
Wood
in
K&
S
(
SATotal)
16.4
m2/
package
All
surfaces
except
the
bottom
will
be
exposed
to
rainwater
Surface
area
of
Top
of
Wood
in
K&
S
(
SATop)
2.98
m2/
package
0.61
m
x
4.88
m
1.19x105
cm3/
package
Quantity
of
Leachate
Collected
per
lumber
package
in
K&
S
(
Vleachate)
119
L/
package
According
to
Krahn
and
Strub
(
1990),
the
standard
leachate
collection
tray
is
1.52
m
x
5.2
m.
15
mm/
day
of
rain
is
collected.

Rainfall
Intensity
(
I)
0.003
m/
hr
Krahn
and
Strub
(
1990)
Octanol­
Water
Partition
Coefficient
(
Log
Kow)
3.12
KOWWIN
v1.67
Organic
Carbon
Partition
Coefficient
(
KOC)
809
Karickhoff
et
al.
(
1979)
use
the
following
approximation
to
determine
KOC:
Log
KOC=
Log
KOW­
0.21
Determination
of
Mo
Eight
TCMTB
products
were
found
that
listed
sapstain
control
as
a
potential
use
(
see
Appendix
B).
Of
these
products,
the
one
with
the
highest
listed
application
rate
(
EPA
Reg.
#
1448­
55)
stated
that,
for
sapstain
control,
the
product
should
be
used
at
a
rate
of
0.216
lbs
a.
i./
gallon
of
water.
Lumber
can
then
be
treated
via
dipping
or
pressure
impregnation
of
the
wood.
For
this
assessment,
it
is
assumed
that
treatment
occurs
via
dipping.

Aschacher
and
Gruendlinger
(
2000)
have
measured
uptake
of
antisapstain
dipping
solution
by
pine
boards.
Freshly
sawn
pine
boards
(
2.3
x
10
x
50
cm,
code
R2
and
R2
Ab)
were
dipped
into
a
1.5%
Busan
30
L
solution
(
a.
i.:
2­
thiocyanomethylthiobenzthiazole
One
set
of
samples
was
treated
in
April
1997,
and
another
set
was
treated
in
April
1998.
For
each
type
of
board
treated
each
year,
the
uptake
was
measured
based
on
the
average
of
7
boards.
The
results
of
the
tests
are
shown
in
Table
2.
The
average
uptake,
based
on
the
measurement
of
28
boards,
was
163
g
solution/
m2.
37
Table
2.
Uptake
of
1.5%
Busan
30
L
Dipping
Solution
Sample
Type
Average
Uptake
(
g
solution/
m2
surface
area)
R2,
1997
158
R2
ab,
1997
148
R2,
1998
173
R2
ab,
1998
173
Average
163
Source:
Aschacher
and
Gruendlinger,
2000.

It
is
assumed
that
the
quantity
of
TCMTB
solution
taken
up
by
pine
boards
via
dipping
is
the
same
as
the
uptake
rate
measured
by
Aschacher
and
Gruendlinger
(
2000)
for
Busan
30
L.
Based
on
the
Krahn
and
Strub
(
1990)
protocol,
the
surface
area
of
the
leachable
wood
in
the
lumber
pile
(
SAtotal)
is
16.3
m2
(
see
Table
1).
Therefore,
the
quantity
of
solution
that
is
taken
up
by
the
leachable
portion
of
wood
is
2,670
g.
Since
26
gallons
of
solution
contain
one
gallon
of
antisapstain
product,
and
since
the
antisapstain
products
contain
50%
a.
i.,
this
corresponds
to
a
Mo
of
69.1
g
a.
i.
The
calculations
are
shown
in
Table
3.

Table
3.
Calculations
for
Mo
Parameter
Value
Rationale
Uptake
rate
163
g
solution/
m2
Aschacher
and
Grundlinger
(
2000).
See
Table
1.
Quantity
of
solution
taken
up
by
leachable
area
2,670
g
solution
Surface
area
of
leachable
wood
=
16.4
m2/
lumber
pile
(
See
Table
1)
Quantity
of
antisapstain
in
diluted
solution
0.216
lbs
a.
i.
/
gallon
solution
Product
#
1448­
55
(
see
Appendix
B)

Density
of
solution
8.34
lbs
solution
/
gallon
solution
Assuming
that
the
diluted
solution
has
the
density
of
water
Mass
a.
i.
in
leachable
area
(
Mo)
69,100
mg
a.
i.
Quantity
of
antisapstain
in
diluted
solution
/
Density
of
solution
*
Uptake
rate
*
(
1000
mg/
g)

Based
on
the
calculations
in
Tables
1
and
3,
Equation
7
can
be
simplified
to:

(
)
i
i
i
i
t
t
t
t
i
e
e
e
e
C
5
1
5
1
10
74
.
6
10
74
.
6
01
.
0
809
4
.
16
003
.
0
98
.
2
01
.
0
809
4
.
16
003
.
0
98
.
2
583
119
100
,
69
 
 
 
 
×
 
×
 

  

 

  
 

×
×
×
 

  

 

  
 

×
×
×
 

 
×
=

 
 

 
 

 
 

 
 
 
×
=
Eq.
8
where
Ci
is
in
units
of
mg/
L
(
ppm),
and
time
is
in
hours.

Calculations
for
Ci
are
shown
in
Table
4.
Because
the
estimated
leaching
is
slow,
Ci
is
nearly
constant
for
all
16
leaching
cycles.
Using
the
Ci
values
in
Equation
2,
the
concentration
of
leachate
(
Cleachate)
was
determined
to
be
0.196
ppm.
Table
4.
Calculations
for
Ci
Leaching
Cycle
Hours
of
Leaching
Concentration
of
Leachate
(
Ci)
(
mg/
L)

1
5
0.196
2
10
0.196
3
15
0.196
4
20
0.196
5
25
0.196
6
30
0.196
7
35
0.196
8
40
0.196
9
45
0.196
10
50
0.196
11
55
0.196
12
60
0.196
13
65
0.196
14
70
0.196
15
75
0.196
16
80
0.195
aOne
leaching
cycle
in
the
Krahn
and
Strub
protocol
corresponds
to
5
hours
of
rainfall.
bSee
Equation
8.

Dilution
Factor
Krahn
and
Strub
(
1990)
assume
that
leachate
entering
the
storm
drain
is
diluted
with
extra
runoff
water
at
a
1:
15
ratio.
This
is
based
on
measurements
of
runoff
in
storm
drains
at
facilities
using
antisapstain
chemicals
in
British
Columbia.
Use
of
the
ratios
1:
6
and
1:
23
were
also
suggested
by
Krahn
and
Strub
(
1990)
to
determine
a
"
general
industry
wide"
predicted
runoff
concentration.
These
values
were
used
in
this
assessment.
The
estimated
leachate
concentration
(
0.196
ppm)
was
used
in
conjunction
with
these
dilution
factors
to
estimate
runoff
concentrations
(
Table
5).

Table
5.
Estimated
Runoff
Concentrations
Parameter
Dilution
Factor
Estimated
Runoff
Concentration
(
ppm)
a
High­
end
dilution
23.0
0.00852
Typical
dilution
15.0
0.0131
Low­
end
dilution
6.00
0.0327
aEstimated
Runoff
Concentration
=
Estimated
Leachate
Concentration
(
0.196
ppm)
/
Dilution
Factor
Uncertainties
and
Limitations
 
Krahn
and
Strub
(
1990)
note
that
the
concentrations
of
antisapstain
chemical
in
runoff
will
be
affected
by
numerous
variables,
including:
chemical
formulation,
chemical
retention
in
wood,
rough
vs.
planed
lumber
cut,
lumber
packaging
and
stacking,
drying
time
prior
to
exposure
to
precipitation,
precipitation
duration,
precipitation
intensity,
precipitation
frequency,
precipitation
pH,
quantity
of
treated
lumber
on
the
storage
site,
species
of
lumber
treated,
general
house
keeping
practices,
whether
the
lumber
is
1st,
2nd,
or
3rd
growth,
solubility
of
the
chemical
in
water,
diffusion
of
the
chemical
into
the
wood,
additives
in
the
formulations,
exposure
and
degradation
due
to
ultraviolet
light,
microbial
action,
ambient
temperatures,
and
affinity
of
the
chemical
to
soils
and
to
yard
surfaces.
 
Information
regarding
the
leaching
behavior
of
TCMTB­
treated
wood
is
limited.
It
is
unclear
how
well
the
method
used
above
predicts
the
results
of
a
study
conducted
using
the
protocol
described
by
Krahn
and
Strub
(
1990).
 
It
was
assumed,
for
this
assessment,
that
rain
events
are
of
equal
intensity
and
duration.
Variations
in
the
intensities
and
durations
of
rain
events
would
affect
the
results.
 
Krahn
and
Strub
(
1990)
obtained
a
dilution
factor
of
15
based
on
a
study
of
antisapstain
facilities
in
British
Columbia.
The
dilution
factor
is
dependent
on
the
intensity
of
rainfall
events.
There
is
no
reason
to
expect
that
the
average
rainfall
intensity
in
British
Columbia
would
be
representative
of
the
average
rainfall
intensity
of
the
United
States;
however,
for
lack
of
better
data,
the
value
was
used.
 
Krahn
and
Strub
(
1990)
assume
that
any
batch
of
treated
wood
remains
in
the
yard
for
16
rain
cycles.
The
frequency
of
rainfall
events
in
British
Columbia
may
not
be
representative
of
the
frequency
of
rainfall
events
in
the
United
States;
therefore,
the
use
of
16
rain
cycles
may
not
be
an
accurate
description
of
treatment
facilities
in
the
United
States.

 
The
model
is
sensitive
to
the
selection
of
Z,
the
thickness
of
the
leachable
region,
and
the
depth
to
which
the
antisapstain
is
assumed
to
penetrate.
Although
the
value
of
0.01
m
is
based
on
the
value
used
in
the
Wood
Leaching
Model
(
WLM),
it
is
unclear
how
this
value
was
derived
and
if
use
of
the
value
is
reasonable
for
a
dipping
treatment.
References
Aschacher
G
and
Gruendlinger
R,
2000.
Methods
to
evaluate
the
ecotoxicological
risks
of
antisapstain
preservatives.
Holzforschung,
Austria
Research
and
Development.
www.
holzforschung.
at/
english/
img_
eng/
ascha200.
pdf.

Addinsoft,
2004.
XLSTAT
v7.5.
http://
www.
xlstat.
com.

Karickhoff
SW,
DS
Brown,
TA
Scott,
1979.
Sorption
of
Hydrophobic
Pollutants
on
Natural
Sediments.
Water
Resources.
13:
241­
248.

Krahn
P
and
Strub
R,
1990.
Standard
Leaching
Test
for
Antisapstain
Chemicals:
Regional
Program
Report
90­
10.
Environment
Canada,
Conservation
and
Protection,
Pacific
and
Yukon
Region
North
Vancouver,
BC.

Lee
R,
2004.
WLM
recommendation
regarding
chemical
generalization.
Memorandum
to
Siroos
Mostaghim,
USEPA.
December
15,
2004.

USEPA,
2004.
Wood
Leaching
Model:
Chemical
Concentration
Screening
Tool,
v1.0.
USEPA/
OPPT/
AD,
developed
by
Versar,
Inc.
Appendix
A:
KOWWIN
Results
Log
Kow
(
estimated):
3.12
Experimental
Database
Structure
Match:
Name
:
2(
Thiocyanate­
MeS)
Bzthiazole
CAS
Num
:
021564­
17­
0
Exp
Log
P:
3.30
Exp
Ref
:
Chem
Inspect
Test
Inst
(
1992)

SMILES
:
C(#
N)
SCSc2nc1ccccc1s2
CHEM
:
TCMTB
MOL
FOR:
C9
H6
N2
S3
MOL
WT
:
238.34
­­­­­­­+­­­­­+­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­­­+­­­­­­­­
TYPE
|
NUM
|
LOGKOW
FRAGMENT
DESCRIPTION
|
COEFF
|
VALUE
­­­­­­­+­­­­­+­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­­­+­­­­­­­­
Frag
|
1
|
­
CH2­
[
aliphatic
carbon]
|
0.4911
|
0.4911
Frag
|
7
|
Aromatic
Carbon
|
0.2940
|
2.0580
Frag
|
1
|
­
S­
[
aliphatic
sulfur,
one
aromatic
attach]|
0.0535
|
0.0535
Frag
|
1
|
Aromatic
Sulfur
|
0.4082
|
0.4082
Frag
|
1
|
­
S­
[
aliphatic
attach]
|­
0.4045
|
­
0.4045
Frag
|
1
|
Aromatic
Nitrogen
[
5­
member
ring]
|­
0.5262
|
­
0.5262
Frag
|
1
|
C#
N­
S
[
cyano,
sulfur
attach]
|
0.3540
|
0.3540
Factor|
1
|
Ortho­
Alkyloxy(
thio)
to
1
aromat
nitrogen
|
0.4549
|
0.4549
Const
|
|
Equation
Constant
|
|
0.2290
­­­­­­­+­­­­­+­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­­­+­­­­­­­­
Log
Kow
=
3.1180
N
S
S
N
S
Log
Kow
(
estimated):
3.12
Appendix
B:
List
of
TCMTB
Products
Labeled
for
Use
in
Sapstain
Control
Product
Number
Percent
a.
i.
Density
(
lbs/
gal)
Application
Rate
Listed
on
Label
Application
Rate
Units
Listed
on
Label
Application
Rate
(
lbs
a.
i./
gal
H2O)

1448­
55
30
9
0.08
gal
prod/
gal
H2O
0.216
1448­
100
5
7.8
0.48
gal
prod/
gal
H2O
0.1872
1448­
376
2.5
8.3
960
lbs
prod/
1000
gal
H2O
0.024
1448­
81
10
9
180
lbs
prod/
1000
gal
H2O
0.018
1448­
99
10
8.2
240
gal
prod/
1000
gal
H2O
0.1968
1448­
102
2.5
8.6
96
lbs
prod/
1000
gal
H2O
0.0024
1448­
377
10
9.2
180
lbs
prod/
1000
gal
H2O
0.018
1448­
386
5
8.5
480
gal
prod/
1000
gal
H2O
0.204
