UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
February
27,
2006
MEMORANDUM
SUBJECT:
Environmental
Effects
Assessment
of
Didecyl
dimethyl
ammonium
chloride
(
DDAC)
for
the
Reregistration
Eligibility
Decision
(
RED)
Document
Case
No.:
3003
DP
Barcode:
323305
FROM:
David
C.
Bays,
Microbiologist
Risk
Assessment
and
Science
Support
Branch
(
RASSB)
Antimicrobials
Division
(
7510C)

TO:
Mark
Hartman,
Branch
Chief
Ben
Chamblis,
Acting
Team
Leader
Najm
Shamim,
Risk
Assessor
Regulatory
Management
Branch
II
Antimicrobials
Division
(
7510C)

Tracy
Lantz,
Chemical
Review
Manager
Regulatory
Management
Branch
I
Antimicrobials
Division
(
7510C)

THRU:
Rick
Petrie,
Acting
Team
Leader,
Team
Three
Risk
Assessment
and
Science
Support
Branch
(
RASSB)
Antimicrobials
Division
(
7510C)

Norman
Cook,
Branch
Chief
Risk
Assessment
and
Science
Support
Branch
(
RASSB)
Antimicrobials
Division
(
7510C)

Chemical
Name
PC
Code
CAS#
Common
Name
Didecyl
dimethyl
ammonium
chloride
069149
7173­
51­
5
DDAC
Environmental
Effects
Science
Chapter
and
Assessment
on
DDAC
is
submitted
for
Reregistration
Eligibility
Decision
(
RED).
Page
2
of
33
ECOLOGICAL
HAZARD
AND
ENVIRONMENTAL
RISK
ASSESSMENT
CHAPTER
Didecyl
Dimethyl
Ammonium
Chloride
(
DDAC)

PC
Code
069149
CASE
No.:
3003
02/
02/
2006
David
C.
Bays
Antimicrobials
Division
Office
of
Pesticide
Programs
U.
S.
Environmental
Protection
Agency
1200
Pennsylvania
Avenue,
NW
Washington,
DC
20460
Page
3
of
33
Table
of
Contents
I.
Summary
of
Uses                            
3
II.
Ecological
Toxicity
Data
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4
A.
Toxicity
to
Terrestrial
Animals
.
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4
1.
Birds,
Acute
and
Subacute
                  .. 
4
2.
Mammals,
Acute
and
Chronic
.
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.
.
5
B.
Toxicity
to
Aquatic
Animals
   ..                ..
6
1.
Freshwater
Fish,
Acute
.
.
.
.
.
.
.
.
.
.
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.
.
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.
.
.
6
2.
Freshwater
Fish,
Chronic
          .       . 
8
3.
Freshwater
Invertebrates,
Acute       .        ...
8
4.
Freshwater
Invertebrates,
Chronic
               
9
5.
Estuarine
and
Marine
Organisms
               ..
10
C.
Toxicity
to
Plants
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.10
III.
Risk
Assessment
and
Risk
Characterization
.
.
.
.
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.
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.
.
11
A.
Environmental
Fate
Assessment
Summary
.
.
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.
.
13
B.
Environmental
Exposure
Assessment
                ..
14
C.
Endangered
Species
Considerations
.
.
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.
26
III.
Confirmatory
Data
Required.
.
.
.
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.
..
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.
27
IV.
Label
Hazard
Statements
for
Terrestrial
and
Aquatic
Organisms.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
.
27
V.
References
.
.
.
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.
.
.
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.
29
Page
4
of
33
I.
Summary
of
Uses
DDAC
includes
structurally
similar
quaternary
ammonium
compounds
(
quats)
that
are
characterized
by
having
a
positively
charged
nitrogen
atom
covalently
bonded
to
two
alkyl
groups
(
one
at
least
eight
carbons
in
length)
and
two
methyl
groups.
These
chemicals
are
highly
water
soluble
and
have
a
wide
variety
of
uses
and
formulations.
The
following
is
a
list
of
the
general
uses
of
these
chemicals:

CURRENT
USES
Algicide/
Algistat
Bactericide/
Bacteriostat
Fungicide/
Fungistat
Insecticide
 
termiticide
(
wood
preservative)
Disinfectant
Microbiocide/
Microbiostat
Miticide
Mold
and
mildew
control
Molluscicide
Sanitizer
(
food
and
non­
food
contact
hard
surface)
Slimicide
Tuberculocide
Virucide
The
specific
uses
include
Agricultural,
Agricultural
Premises
and
Equipment
(
hatchery
rooms,
incubators,
mushroom
farms,
animal
housing
facilities,
citrus
farms,
swine/
turkey
poultry
farms,
flower
shops,
greenhouses),
Industrial
processes
and
water
systems
(
oil
fields,
cooling
water)
Swimming
Pools,
Aquatic
areas
(
decorative
pools
and
fountains,
ponds,
water
displays,
standing
water,
greenhouse/
nurseries),
Wood
treatment,
Residential
and
Public
Access
Premises
(
homes,
mobile
homes,
cars,
campgrounds,
trailer
campers,
boats,
playgrounds,
public
facilities,
trucks),
Medical
Premises
and
Equipment
(
hospitals,
health
care
facilities,
medical/
dental
offices,
nursing
homes,
operating
rooms,
patient
care
facilities,
clinics,
isolation
wards,
medical
research
facilities,
autopsy
rooms,
ICU
areas,
recovery
anesthesia,
emergency
rooms,
X­
ray
cat
labs,
newborn
nurseries,
orthopedics,
respiratory
therapy,
acute
care
institutions,
alternate
care
institutions,
healthcare
institutions,
funeral
homes,
mortuaries,
day­
care
facilities),
Commercial,
Institutional
and
Industrial
Premises
and
Equipment
(
athletic/
recreational
facilities,
exercise
facilities,
schools,
colleges,
dressing
rooms,
transportation
terminals,
locker
rooms,
motels,
hotels,
barber
and
beauty
salons,
health
clubs,
emergency
vehicles,
correctional
facilities,
factories,
commercial
florists,
dorms,
convenience
stores,
recreational
centers,
offices,
commercial
and
institutional
laundry
mats,
industrial
premise),
Food
Handling/
Storage
Establishments
Premises
and
Equipment
(
Disinfectant)
(
restaurants,
food
service
establishments,
food
processing
plans/
facilities,
bottling
and
beverage
processing
plans,
bars,
cafeterias,
supermarkets,
dairies,
egg
processing
plants,
federally
inspected
meat
and
poultry
plants,
food
handling
areas,
food
preparation
areas,
food
storage
areas,
institutional
kitchens,
USDA
inspected
food
processing
facilities,
breweries,
fast
food
operations,
tobacco,
rendering
plants,
fishery/
milk/
citrus/
wine/
ice
cream/
potato
processing
plants,
school
Page
5
of
33
lunchrooms),
and
Clean/
Deodorization
(
water/
smoke
restoration,
sewer
backup/
river
flood
cleanup,
garbage
storage
areas,
pet
areas,
garbage
bins
and
cans)

The
following
are
the
current
formulation
types
for
these
chemicals:

Soluble
concentrate
Ready
to
use
solution
Pressurized
liquid
Water
soluble
packaging
Formulation
intermediate
Wettable
powder
Impregnated
materials
Emulsifiable
concentrate
II.
Ecological
Toxicity
Data
A.
Toxicity
to
Terrestrial
Animals
1.
Birds,
Acute
and
Subacute
For
indoor
uses,
an
acute
oral
toxicity
study
using
the
technical
grade
of
the
active
ingredient
(
TGAI)
is
required
to
establish
the
toxicity
of
these
chemicals
to
birds.
The
preferred
test
species
is
either
mallard
duck
(
a
waterfowl)
or
northern
bobwhite
quail
Ian
upland
game
bird).
Several
avian
acute
toxicity
studies
were
found
in
the
Agency's
files
for
this
chemical.
Avian
acute
oral
toxicity
testing
(
850.2100/
71­
1),
preferably
using
the
bobwhite
quail,
is
required
to
support
the
currently
registered
uses
of
these
chemicals.

Avian
dietary
toxicity
studies
using
the
TGAI
of
these
chemicals
are
not
required
for
indoor
uses.

The
results
from
the
avian
acute
toxicity
and
dietary
studies
obtained
from
the
Agency's
files
are
summarized
in
the
table
below
(
Table
1).

Table
1
Test
and
Organism
Results
LC50
(
mg/
L)
or
LD50
(
mg/
kg)
Toxicity
Category
Comments
Reference
Avian
dietary
LC50
Bobwhite
Quail
(
Colinus
virginianus)
239
NOEC
<
31
Practically
nontoxic
Core
study
Long
et
al.
1991a
MRID#
­
41785801
Avian
dietary
LC50
Mallard
Duck
(
Anas
platyrhynchos
)
>
5620
NOEC
=
562
Practically
nontoxic
Core
study
Long
et
al.
1991b
MRID#
­
41785802
Page
6
of
33
Avian
single
dose
oral
LD50
Bobwhite
Quail
(
Colinus
virginianus)
217
Moderately
toxic
Core
Study
Campbell
et
al.
1991
MRID#
­
41785803
Eight
day
dietary
LC50
Bobwhite
Quail
(
Colinus
virginianus)
>
5000
Practically
nontoxic
Supplemental
Study
Henck,
H.
W.
1986
ACC#
­
40129801
8­
day
dietary
LC50
Mallard
Duck
(
Anas
platyrhynchos)
>
5620
Practically
nontoxic
Core
Study
Fink,
R.
and
Beavers
J.
1985
ACC#
­
258798
8­
day
dietary
LC50
Bobwhite
Quail
(
Colinus
virginianus)
>
5620
Practically
nontoxic
Core
Study
Fink,
R.
and
Beavers,
J.
1982
ACC#
­
258798
Acute
Oral
LD50
Bobwhite
Quail
(
Colinus
virginianus)
54.4
Moderately
toxic
Core
Study
Fink,
R.
and
Beavers,
J.
1985
ACC#
­
258798
8­
day
dietary
LC50
Bobwhite
Quail
(
Colinus
virginianus)
1950
+
236.6
None
given
Supplemental
Study
Cannon
Lab.
1973
ACC#
­
132164
8­
day
dietary
LC50
Mallard
Duck
(
Anas
platyrhynchos)
>
3500
None
given
Supplemental
Study
Cannon
Lab.
1973
ACC#
­
132164
Acute
Oral
Toxicity
LD50
Mallard
Duck
(
Anas
platyrhynchos)
0.33
gm/
kg
None
given
Supplemental
Study
Cannon
Lab.
1977
ACC#
­
225889
The
results
of
the
dietary
avian
studies
indicate
that
DDAC
is
practically
non­
toxic
to
both
mallard
duck
and
bobwhite
quail.
In
the
Acute
oral
studies,
the
chemical
was
found
to
be
moderately
toxic
to
bobwhite
quail.
All
of
these
studies
were
considered
to
be
core
and
met
guideline
requirements
at
the
time
they
were
submitted
to
the
Agency.
Page
7
of
33
2.
Mammals
A
summary
of
mammalian
toxicity
of
DDAC
is
presented
in
the
"
Evaluation
of
Toxicity
Database
for
Reregistration
Eligibility
Decision
Document
Disciplinary
Chapter".

B.
Toxicity
to
Aquatic
Animals
1.
Freshwater
Fish,
Acute
Freshwater
fish
toxicity
studies
using
the
TGAI
are
required
to
establish
the
toxicity
of
these
chemicals
to
fish.
Data
are
generally
required
for
only
one
species.
Testing
in
two
fish
species
is
required
for
stable
chemicals
with
high
volume
effluents
(
e.
g.,
including,
but
not
limited
to,
egg
washing,
fruit
and
vegetable
rinses,
swimming
pools
or
materials
preservatives)
and
if
the
LC50
in
the
first
species
is
greater
than
(>)
1
ppm.
The
preferred
test
species
are
rainbow
trout
(
a
coldwater
fish)
and
bluegill
sunfish
(
a
warmwater
fish),
although
other
test
species
identified
in
the
OPPTS
Guideline
(
i.
e.,
OPPTS
850.1075
(
e)(
4)(
i)(
A))
may
also
be
used.
Several
freshwater
fish
acute
toxicity
studies
were
identified
from
peer­
reviewed
literature
(
Table
2).
Several
freshwater
fish
acute
toxicity
studies
were
found
in
the
Agency's
files
(
Table
3).
Freshwater
fish
acute
toxicity
testing
(
850.1075/
72­
1)
on
one
species,
preferably
the
rainbow
trout,
is
required
to
support
the
currently
registered
uses
of
this
chemical.

The
results
from
freshwater
fish
acute
toxicity
studies
obtained
from
peer­
reviewed
literature
are
summarized
in
the
table
below
(
Table
2).

Table
2
Organism
Results
Comments
Reference
White
Sturgeon
(
Acipenser
transmontanus)
Larvae:
24­
h
LC50
=
0.74
ppb
(
0.1,
1.0);
100%
mortality
at
>
1.0
ppb;
NOEC
=
0.5
ppb
Fry:
100%
mortality
at
10.0
ppb
8
day
old
larvae
42
day
old
fry
96
hour
test
duration
no
mortality
in
control
groups
Bennett,
W.
R.
and
Farrell,
A.
P.
1998.
Water
Qual.
Res.
J.
Can.
33(
1)
95­
110.

Rainbow
Trout
(
Oncorhynchus
mykiss)
96­
h
LC50
=
0.409
mgL­
1
96
hour
test
duration
flow­
through
system
Wood,
A.
W.
et.
al.
1996.
Can.
J.
Fish.
Aquat.
Sci.
53:
2424­
2432.
Japanese
Makata
(
Oryzias
latipes)
and
Zebrafish
(
Danio
rerio)
IC25
=
439.7
+
9.9
ug/
l
(
NOEC
=
312.5
ug/
l)
for
zebrafish;
IC25
=
1563
+
14.5
ug/
l
(
NOEC
=
1250
ug/
l)
for
makata
9
day
test
for
zebrafish
14
day
test
for
makata
Tatarazako,
N.
et
al.
2002.
Health
Sci.
48(
4):
359­
365.

White
Sturgeon
(
Acipenser
LC50
=
10
to
50
ug/
l
for
3
day,
58.5
ug/
l
96­
hr.
static
renewal
method
using
3,
11,
Teh,
S.
J.
et
al.
2003.
Toxicol.
Chem.
Page
8
of
33
transmontanus)
for
11
day,
99.7
ug/
l
for
42
day
old
larvae;
LC50
=
100
to
250
ug/
l
for
78
day
old
juveniles
42
day
larvae,
and
78
day
old
juveniles
22(
9):
2152­
2158.

Rainbow
Trout
(
Orcorhynchus
mykiss)
LC50
=
537
ug/
l
96­
hr.
test
using
juvenile
rainbow
trout
Bailey,
H.
C.
et
al.
1999.
Water
Res.
33(
10):
2410­
2414.

The
results
from
the
above
fish
acute
toxicity
studies
obtained
from
the
literature
indicate
that
DDAC
is
toxic
to
fish
at
microgram
concentrations.
The
chemical
would
be
considered
to
be
very
highly
toxic
to
fish.
However
these
studies
do
not
meet
current
guideline
requirements.

The
results
from
freshwater
fish
acute
toxicity
studies
obtained
from
the
Agency's
files
are
summarized
in
the
table
below
(
Table
3).

Table
3
Test
and
Organism
Results
LC50
(
mg/
L)
Toxicity
Category
Comments
Reference
Acute
Toxicity
LC50
Rainbow
Trout
(
Onchorynchus
mykiss)
478
Practically
nontoxic
Supplemental
Study
Rhodes,
R.
E.
2000a
MRID#
­
41592002
Acute
Toxicity
LC50
Bluegill
Sunfish
(
Lepomis
macrochirus)
188
Practically
nontoxic
Supplemental
Study
Rhodes,
R.
E.
2000b
MRID#
­
45192001
Static
Acute
Toxicity
LC50
Sheepshead
minnow
(
Cyprindon
variegates)
0.96
Highly
toxic
Core
Study
Collins,
M.
K.
1994
MRID#
­
43620001
Static
Acute
Toxicity
LC50
Bluegill
Sunfish
(
Lepomis
macrochirus)
0.32
Highly
toxic
Core
Study
LeLievre,
M.
K.
1990a
MRID#
­
41578001
Static
Acute
Toxicity
LC50
Coho
Salmon
(
Oncorhynchus
1.0
Highly
toxic
Core
Study
LeLievre,
M.
K.
1990b
MRID#
­
41578003
Page
9
of
33
kisutch)
Acute
Toxicity
96­
hr
LC50
Blue
gill
sunfish
(
Lepomis
macrochirus)
0.5
Highly
toxic
Core
Study
Onyx
Chemical
Co.
1982a
PROJ#
­
038901
Acute
Toxicity
96­
hr
LC50
Rainbow
Trout
(
Oncorhynchus
mykiss)
2.8
Moderately
toxic
Core
Study
Onyx
Chemical
Co.
1982b
PROJ#
­
038901
Acute
Toxicity
96­
hr
LC50
Rainbow
Trout
(
Oncorhynchus
mykiss)
1.6
Moderately
toxic
Core
Study
Surpremant,
D.
C.
1986
ACC#
­
40129801
96
hr.
Static
Bioassay
LC50
Bluegill
Sunfish
(
Lepomis
macrochirus)
0.27
Not
given
Supplemental
Wells
Labs
1971a
ACC#
­
007958
96
hr.
Static
Bioassay
LC50
Rainbow
Trout
(
Oncorhynchus
mykiss)
1.1
Not
given
Supplemental
Wells
Labs
1971b
ACC#
­
007958
As
shown
in
Table
3,
the
toxicity
ranged
from
0.27
to
478
mg/
L,
which
ranged
in
toxicity
category
from
practically
nontoxic
to
moderately
toxic
to
highly
toxic,
depending
on
the
product
being
tested.

2.
Freshwater
Fish,
Chronic
Fish
early
life
stage
testing
is
not
required
for
the
currently
registered
indoor
uses
of
this
chemical.

3.
Freshwater
Invertebrates,
Acute
A
freshwater
aquatic
invertebrate
toxicity
test
using
the
TGAI
is
required
to
establish
the
toxicity
of
a
pesticide
to
aquatic
invertebrates.
The
preferred
test
species
is
Daphnia
magna
or
Daphnia
pulex.
Several
studies
testing
these
organisms
were
found
in
the
Agencies
files
(
Table
4).
Freshwater
invertebrate
acute
toxicity
testing
(
850.1010/
72­
2)
is
required
for
the
currently
registered
uses
of
this
chemical.
Page
10
of
33
Table
4
Test
and
Organism
Results
Toxicity
Category
Comments
Reference
Freshwater
invertebrate
static
acute
toxicity
Daphnia
magna
48­
hr.
EC
50
=
94
ug/
l
Very
highly
toxic
Core
Study
LeLievre,
M.
K.
1990c
MRID#
­
41578002
Freshwater
Invertebrate
Static
Acute
Toxicity
Daphnia
magna
48­
hr.
LC50
=
0.018
mg/
l
Very
highly
toxic
Core
Study
Onyx
Chemical
Co.
1982c
PROJ#
­
038901
Acute
Toxicity
Daphnia
pulex
48­
hr.
LC50
=
0.052
mg/
l
Very
highly
toxic
Core
Study
Surprenant,
E.
C.
1987
ACC#
­
40129801,
02,
03
Static
48­
hr.
toxicity
study
Daphnia
magna
48­
hr.
LC50
=
0.095
mg/
l
None
given
Supplemental
Study
Roberts,
S.
1977
No.
­
7E­
6686
48­
hr.
Static
aquatic
invertebrate
study
Daphnia
magna
48­
hr.
LC50
=
0.1
mg/
l
None
given
Supplemental
Study
Cannon
Labs
1976
ACC#
­
225596
As
shown
in
Table
4,
this
chemical
is
very
highly
toxic
to
aquatic
invertebrates.

One
study
was
found
in
the
open
literature
and
is
summarized
in
Table
5.

Table
5
Organism
Results
Comments
Reference
Daphna
magna
IC25
=
211.2
+
6.8
ug/
l
(
NOEC
=
125
ug/
l)
21
day
test
Tatarazako,
N.
et
al.
2002.
Health
Sci.
48(
4):
359­
365.

The
Daphnid
study
in
Table
5
indicates
that
DDAC
is
very
highly
toxic
to
Daphnia
magna.

4.
Freshwater
Invertebrates,
Chronic
Chronic
aquatic
invertebrate
testing
is
conditionally
required
for
the
currently
registered
wood
preservative
use
of
this
chemical.
One
study
was
found
in
the
Agency's
files
(
Table
6).
Page
11
of
33
Table
6
Test
and
Organism
Results
Toxicity
Category
Comments
Reference
Whole
Sediment
chronic
toxicity
invertebrate
test
Midge
(
Chironomus
tentans)
LC50
=
>
1000
(
mg
ai/
kg
dry
sediment)
EC50
=
1981
None
given
Supplemental
Study
England,
D.
C.
and
Leak,
T.
1995
MRID#
­
45821701
The
results
of
the
above
study
indicate
that
DDAC
is
practically
non­
toxic
to
the
Midge
in
a
whole
sediment
chronic
toxicity
test.
The
test
was
considered
Supplemental.

5.
Estuarine
and
Marine
Organisms
Acute
toxicity
testing
with
estuarine
and
marine
organisms
using
the
TGAI
is
conditionally
required
for
the
wood
preservative
uses
of
this
chemical.
Several
studies
on
marine/
estuarine
invertebrates
were
found
in
the
Agency's
files
(
Table
7).

Table
7
Test
and
Organism
Results
Toxicity
Category
Comments
Reference
Estuarine
Invertebrate
Static
Acute
Toxicity
Mysid
Shrimp
(
Mysidopsis
bahia)
96­
hr.
LC50
=
69
ug/
l
Very
highly
toxic
Core
Study
LeLievre,
M.
K.
1990d
MRID#
­
41578004
48­
hr.
EC50
and
96­
hr.
LC50
oyster
eggs
and
straight­
hinge
larvae
Eggs:
9­
hr.
EC50
=
19
ppm
Larvae:
48­
hr.
LC50
=
10.5
ppm;
96­
hr.
LC50
=
6.4
ppm
None
given
Core
Study
Cannon
Labs
1974a
ACC#
­
249002
96­
hr.
LC50
marine
blue
crab
96­
hr.
LC50
=
2.10
+
1.28
ppm
None
given
Core
Study
Cannon
Labs
1974b
ACC#
­
249002
96­
hr.
LC50
marine
grass
shrimp
96­
hr.
LC50
=
2.78
+
0.29
None
given
Core
Study
Cannon
Labs
1974c
ACC
#
­
249002
Page
12
of
33
As
shown
in
Table
6,
this
chemical
is
very
highly
toxic
to
mysid
shrimp,
practically
non­
toxic
to
oyster
eggs
and
straight­
hinge
larvae,
and
moderately
toxic
to
blue
crab
and
grass
shrimp.
Since
all
the
studies
except
the
mysid
shrimp
are
old,
over
30
years,
the
results
of
the
mysid
shrimp
test
would
be
the
most
reliable.

C.
Toxicity
to
Plants
Terrestrial
and
aquatic
plant
testing
is
required
for
the
registered
wood
preservative
use
of
this
chemical.

There
were
not
aquatic
phytotoxicity
endpoints
reported
in
the
ECOTOX
data
base
(
EPA,
2002).
Two
Alga
toxicity
studies
on
this
chemical
were
found
in
the
Agency's
files
(
Table
8).

Table
8
Test
and
Organism
Results
Toxicity
Category
Comments
Reference
96­
hr.
Toxicity
Test
Freshwater
Alga
(
Selenastrum
capricornutum)
Using
Natural
Surface
Water
EC10
=
9.64
ug
ai/
L
EC50
=
73.2
ug
ai/
L
NOEC
=
27
ug
ai/
L
None
given
Supplemental
Study
Krueger,
H.
O.
et
al.
2003
MRID#
­
45896401
96­
hr
Toxicity
Test
with
Freshwater
Alga
(
Selenastrum
capricornutum)
96­
hr
EC10
=
6.56
ug/
L
EC50
=
14.22
ug/
L
NOEC
=
8
ug/
L
None
given
Core
Study
Krueger,
H.
O.
et
al.
2002
MRID#
­
48596402
As
shown
in
Table
8,
DDAC
was
toxic
to
freshwater
alga
at
microgram
concentrations.

One
study
was
found
in
the
open
literature
and
is
summarized
in
Table
9.

Table
9
Organism
Results
Comments
Reference
Green
alga
(
Selenastrum
capricornutum)
IC25
=
10
+
24.4
ug/
l
(
NOEC
=
25
ug/
l)
72­
hr
test
Tatarazako,
N.
2002
Health
Sci.
48(
4):
359­
365.

The
above
study
indicates
that
DDAC
is
toxic
to
green
alga
at
microgram
concentrations.
Page
13
of
33
III.
Risk
Assessment
and
Characterization
Risk
assessment
integrates
the
results
of
the
exposure
and
ecotoxicity
data
to
evaluate
the
likelihood
of
adverse
ecological
effects.
Also
playing
a
role
is
the
environmental
fate
of
a
chemical.
The
following
sections
present
a
summary
of
the
environmental
fate
of
DDAC
and
an
environmental
exposure
and
ecological
risk
assessment.
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
OPP's
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,
and
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).
Examples
of
toxicity
test
effect
levels
derived
from
the
results
of
longterm
laboratory
studies
that
assess
chronic
effects
are:
(
1)
LOEC
(
birds,
fish,
and
aquatic
invertebrates)
(
2)
NOEC
(
birds,
fish
and
aquatic
invertebrates)
and
(
3)
MATC
(
Maximum
Allowable
Toxic
Concentration)
(
fish
and
aquatic
invertebrates).
For
birds
and
mammals,
the
NOEC
value
is
used
as
the
ecotoxicity
test
value
in
assessing
chronic
effects.
Other
values
may
be
used
when
justified.
Generally,
the
MATC
(
defined
as
the
geometric
mean
of
the
NOEC
and
LOEC)
is
used
as
the
ecotoxicity
test
value
in
assessing
chronic
effects
to
fish
and
aquatic
invertebrates.
However,
the
NOEC
is
used
if
the
measurement
endpoint
is
production
of
offspring
or
survival.

Risk
presumptions,
along
with
the
corresponding
RQs
and
LOCs
are
tabulated
below.

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
Page
14
of
33
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
Fate
Assessment
Summary
(
excerpted
from
the
Environmental
Fate
Science
Chapter
of
this
RED
document)

The
Agency
has
reviewed
various
environmental
fate
studies
and
reports
submitted
for
DDAC.
The
data
indicate
that
DDAC
is
hydrolytically
and
photolytically
stable
under
abiotic
Page
15
of
33
and
buffered
conditions.
Aquatic
metabolism
studies
indicate
that
DDAC
is
also
stable
to
microbial
degradation.
However,
a
report
on
the
biodegradability
of
DDAC
concluded
that
the
degree
of
DDAC
biodegradability
is
variable
and
is
influenced
by
the
chemical
concentration,
alkyl
chain
length,
the
presence
of
anionic
moieties
and
the
quantity
and
characteristics
of
the
microbial
population.
Accordingly,
DDAC
is
considered
biodegradable
under
aerobic
and
anaerobic
conditions
and,
therefore,
environmentally
acceptable.
In
addition,
DDAC
is
immobile
in
soil
because
of
its
strong
tendency
to
bind
to
sediment/
soil.
Bioaccumulation
of
DDAC
in
terrestrial
or
aquatic
organisms
is
not
likely
to
occur.
Further
information
on
the
environmental
fate
of
DDAC
may
be
found
in
the
Environmental
Fate
Chapter
of
this
RED
document.

B.
Environmental
Exposure
and
Ecological
Risk
Assessment
Freshwater
and
estuarine/
marine
aquatic
organisms,
and
plants
could
potentially
be
exposed
to
DDAC
discharged
into
the
aquatic
environment.
The
Agency
conducted
modeling
in
2005
to
estimate
the
exposure
and
environment
risk
resulting
from
such
discharges
of
DDAC
from
the
once­
through
cooling
tower
and
antisapstain
wood
treatment
uses.

(
1)
Tier
I
2005
Probabilistic
Dilution
Modeling
for
once­
through
cooling
tower
use
The
EPA
Office
of
Water
PDM4
Model
was
used
to
estimate
exposure
from
oncethrough
cooling
tower
use
as
a
preliminary
screen
in
the
absence
of
field
residue
data.
Oncethrough
cooling
water
systems
applying
a
continuous
dose
of
pesticide
located
on
low­
flow
streams
(
100
million
gallons
per
day)
were
used
as
the
scenarios
providing
the
maximum
concentrations
of
DDAC
in
the
receiving
water,
e.
g.,
the
"
worst
case"
scenarios.
It
was
assumed
that
the
chemical
was
being
applied
at
the
highest
listed
maintenance
rate
shown
on
any
of
the
DDAC
product
labels.
Actual
probabilities
of
exceedance
of
concentrations
in
receiving
waters
are
likely
lower
than
what
are
shown
in
Table
10
due
to
higher
flow
rates
and
possible
degradation/
dissipation
of
available
DDAC
by
mechanisms
other
than
hydrolysis.
A
summary
of
concentrations
over
time
is
provided
in
Table
10.
The
concentrations
selected
for
analysis
were
the
measured
endpoints
derived
from
the
results
of
the
required
studies
(
see
Section
I.
B.)

Table
10
­
Table
of
LOC's
Taxa
LC50/
EC50
High
Acute
Risk
LOC
(
X
0.5)
Restricted
Use
LOC
(
X
0.1)
Endangered
Species
LOC
(
X
0.05)

Freshwater
fish­
warm
320
ppb
160
ppb
32
ppb
16
ppb
Freshwater
fish
 
cold
1600
ppb
800
ppb
160
ppb
80
ppb
Page
16
of
33
Freshwater
invertebrate
94
ppb
47
ppb
9.4
ppb
4.7
ppb
Marine
fish
96
ppb
48
ppb
9.6
ppb
4.8
ppb
Marine
mollusk
No
data
Marine
invertebrate
69
ppb
34.5
ppb
6.9
ppb
3.45
ppb
Green
alga
14ppb
7ppb
1.4ppb
0.7ppb
Aquatic
vascular
plant
No
data
Freshwater
fish
chronic
No
data
Modeling
Results
for
DDAC
 
Once­
through
Cooling
Use
The
following
tables
list
the
probability
that
levels
of
concern
(
LOCs)
will
be
exceeded
for
aquatic
organisms.
Various
dosages,
dosing
methods
(
continuous
vs
intermittent),
and
water
flow
rates
(
low,
medium,
high
stream
flow
rates)
were
modeled
(
Versar
2006).

Results
are
given
as
percent
of
days
per
year
and
number
of
days
per
year
of
LOC
exceedance
for
the
different
aquatic
animal
and
plant
groups.
BOLD
indicates
exceedance
of
LOC
(
e.
g.,
if
the
number
of
days
exceeded
is
equivalent
to
or
greater
than
number
of
days
used
to
determine
the
toxicology
endpoint,
risk
is
assumed).
Dose
rates
selected
from
labeling
for
this
chemical
were
32
and
63
ppm
for
continuous
feed
and
1000
and
1800
ppm
for
intermittent
feed.
Page
17
of
33
Table
11.
Average
Exceedances,
Low
Continuous
Dose
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
98.2%,
358
days
0.7
ppb
99.8%,
364
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
97.7%,
357
days
0.9
ppb
99.8%,
364
days
ME
Invertebrates
(
4)
69
34.5
ppb
89.9%,
328
days
3.45
ppb
99.1%,
362
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
89.3%,
326
days
3.65
ppb
99.1%,
362
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
86.2%,
315
days
4.75
ppb
98.8%,
361
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
72.4%,
264
days
16
ppb
95.5%,
349
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
58.5%,
214
days
50
ppb
85.5%,
312
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
99.7%,
364
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
99.6%,
364
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
97.8%,
357
days
3.45
ppb
99.9%,
364
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
97.6%,
356
days
3.65
ppb
99.8%,
364
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
96.7%,
353
days
4.75
ppb
99.8%,
364
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
89.5%,
327
days
16
ppb
99.3%,
362
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
76.5%,
279
days
50
ppb
96.5%,
352
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
98.6%,
360
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
98.4%,
359
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
97.6%,
356
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
89.2%,
326
days
16
ppb
99.9%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
77.5%,
283
days
50
ppb
97.4%,
355
days
Page
18
of
33
Table
12.
Average
Exceedances,
High
Continuous
Dose
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
99.6%,
363
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
99.4%,
363
days
0.9
ppb
99.9%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
95.1%,
347
days
3.45
ppb
99.8%,
364
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
94.7%,
346
days
3.65
ppb
99.8%,
364
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
92.5%,
338
days
4.75
ppb
99.7%,
364
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
80.4%,
293
days
16
ppb
98.8%,
360
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
66.7%,
243
days
50
ppb
92%,
336
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
99.9%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
99.9%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
99.1%,
362
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
99%,
361
days
3.65
ppb
99.9%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
98.6%,
360
days
4.75
ppb
99.9%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
94.3%,
344
days
16
ppb
99.8%,
364
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
84.8%,
310
days
50
ppb
98.5%,
360
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
99.7%,
364
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
99.7%,
364
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
99.5%,
363
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
94.9%,
346
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
84.1%,
307
days
50
ppb
99.4%,
363
days
Page
19
of
33
Table
13.
Average
Exceedances,
Low
Intermittent
Dose
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
92.9%,
339
days
0.7
ppb
99.3%,
362
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
90.9%,
332
days
0.9
ppb
99.1%,
362
days
ME
Invertebrates
(
4)
69
34.5
ppb
77.8%,
284
days
3.45
ppb
96.5%,
352
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
77.2%,
282
days
3.65
ppb
96.3%,
351
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
73.9%,
270
days
4.75
ppb
95.2%,
347
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
59%,
215
days
16
ppb
84.3%,
308
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
42.2%,
154
days
50
ppb
73.1%,
267
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
98.6%,
360
days
0.7
ppb
99.9%,
364
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
98.1%,
358
days
0.9
ppb
99.8%,
364
days
ME
Invertebrates
(
4)
69
34.5
ppb
92.7%,
338
days
3.45
ppb
99.3%,
362
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
92.3%,
337
days
3.65
ppb
99.2%,
362
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
90.1%,
329
days
4.75
ppb
99%,
361
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
76.9%,
281
days
16
ppb
96.6%,
353
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
56.7%,
207
days
50
ppb
89.6%,
327
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
99.2%,
362
days
0.7
ppb
99.9%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
99%,
361
days
0.9
ppb
99.9%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
93.1%,
340
days
3.45
ppb
99.6%,
364
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
92.5%,
338
days
3.65
ppb
99.6%,
364
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
89.6%,
327
days
4.75
ppb
99.5%,
363
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
77.9%,
284
days
16
ppb
97.9%,
358
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
66.4%,
242
days
50
ppb
89%,
325
days
Page
20
of
33
Table
14.
Average
Exceedances,
High
Intermittent
Dose
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
96.1%,
351
days
0.7
ppb
99.6%,
364
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
95%,
347
days
0.9
ppb
99.5%,
363
days
ME
Invertebrates
(
4)
69
34.5
ppb
84.5%,
308
days
3.45
ppb
98.1%,
358
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
83.9%,
306
days
3.65
ppb
98%,
358
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
80.5%,
294
days
4.75
ppb
97.4%,
355
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
66.1%,
241
days
16
ppb
90.9%,
332
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
51.2%,
187
days
50
ppb
79.7%,
291
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
99.3%,
363
days
0.7
ppb
99.9%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
99.2%,
362
days
0.9
ppb
99.9%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
95.9%,
350
days
3.45
ppb
99.7%,
364
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
95.7%,
349
days
3.65
ppb
99.7%,
364
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
94.2%,
344
days
4.75
ppb
99.6%,
363
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
84.3%,
308
days
16
ppb
98.4%,
359
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
68.1%,
249
days
50
ppb
93.8%,
342
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
99.8%,
364
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
99.8%,
364
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
96.6%,
353
days
3.45
ppb
99.9%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
96.2%,
351
days
3.65
ppb
99.9%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
94.4%,
344
days
4.75
ppb
99.9%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
83.7%,
306
days
16
ppb
99.6%,
363
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
72.7%,
265
days
50
ppb
93.9%,
343
days
Page
21
of
33
Table
15.
Worst­
Case
Exceedances,
Low
Continuous
Dose
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
99.7%,
364
days
50
ppb
100%,
365
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
99.8%,
364
days
50
ppb
100%,
365
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
99.9%,
365
days
50
ppb
100%,
365
days
Page
22
of
33
Table
16.
Worst­
Case
Exceedances,
High
Continuous
Dose
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
100%,
365
days
50
ppb
100%,
365
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
100%,
365
days
50
ppb
100%,
365
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
100%,
365
days
50
ppb
100%,
365
days
Page
23
of
33
Table
17.
Worst­
Case
Exceedances,
Low
Intermittent
Dose
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
99.7%,
364
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
95.1%,
347
days
50
ppb
100%,
365
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
99.8%,
364
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
96.4%,
352
days
50
ppb
100%,
365
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
99.9%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
96.7%,
353
days
50
ppb
100%,
365
days
Page
24
of
33
Table
18.
Average
Exceedances,
8
Dose
Taxa
(
Duration
of
Acute
Study,
in
Days)
Endpoint
Value
(
From
Study,
ppb)
Levels
of
Concern
(
ppb),
%
Days
Exceeded,
#
Days/
Year
Exceeded
Acute
Nontarget
(
LC50
or
EC50
*
0.5)
Endangered
Species
(
LC50
or
EC50
*
0.05)
Facilities
on
Low
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
99.9%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
98.6%,
360
days
50
ppb
100%,
365
days
Facilities
on
Medium
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
99.1%,
362
days
50
ppb
100%,
365
days
Facilities
on
High
Flow
Streams
FW
Alga
(
Low­
end)
(
4)
14
7
ppb
100%,
365
days
0.7
ppb
100%,
365
days
FW
Invertebrates
(
Lowend
(
2)
18
9
ppb
100%,
365
days
0.9
ppb
100%,
365
days
ME
Invertebrates
(
4)
69
34.5
ppb
100%,
365
days
3.45
ppb
100%,
365
days
FW
Alga
(
High­
end)
(
4)
73
36.5
ppb
100%,
365
days
3.65
ppb
100%,
365
days
FW
Invertebrates
(
Highend
(
2)
95
47.5
ppb
100%,
365
days
4.75
ppb
100%,
365
days
FW
Fish
(
Low­
end)
(
2)
320
160
ppb
100%,
365
days
16
ppb
100%,
365
days
FW
Fish
(
High­
end)
(
2)
1000
500
ppb
99.3%,
363
days
50
ppb
100%,
365
days
Page
25
of
33
Tier
I
once­
through
cooling
tower
modeling
indicates
that
DDAC
use
will
result
in
acute
and
chronic
risk
to
non­
endangered
and
endangered/
threatened
freshwater
fish
and
acute
risk
to
other
aquatic
animals
at
all
dosages
modeled:
32
ppm,
63
ppm,
1000
ppm,
and
1800
ppm.

(
2)
Wood
Leaching
Model
The
DDAC
wood
treatment
use
was
modeled
using
Krahn
and
Strub
­
1990,
to
estimate
expected
environmental
concentrations
(
EEC's).
The
EEC
is
an
estimate
of
the
amount
of
DDAC
that
will
runoff
from
treated
wood
exposed
to
the
elements
when
stored
outdoors.
The
chemical
formulation,
retention
of
chemical
by
the
wood,
rough
vs
smooth
wood
surfaces,
amount
and
timing
of
precipitation,
and
storage
site
conditions
are
some
of
the
variables
that
affect
the
amount
and
timing
of
runoff.
A
total
of
16
rain
cycles
of
equal
intensity
and
duration
were
used
in
this
model.

Estimated
Environmental
Concentrations
(
EECs)
are
as
follows:

The
leaching
study
indicates
that
1.58%
of
DDAC
was
leached
from
the
wood
into
water,
therefore:

(
0.6
lb/
ft3
)
X
(
1
ft3
/
0.0283168
m3
)
x
(
0.4535924
kg/
lb)
X
0.03
=
0.2883328
kg/
m3
30.81
m3
x
0.2883328
kg/
m3
x
0.0158
leach
rate
=
0.1403598
Kg
of
DDAC
=
140.3598
g
of
DDAC
=
140359.8
mg
of
DDAC
It
is
assumed
that
the
water
body
close
to
the
dock
contains
between
6
acre
feet
(
7400891
liters)
to
24
acre
foot
(
29603736
liters)
of
water.
Using
the
following
relationship
the
amount
of
DDAC
in
fresh
water
will
be:

(
140359.8
mg
of
DDAC)/
7400891
=
0.01896526mg/
L
=
0.01896526
ppm
of
DDAC
in
water
=
18.97
ppb
of
DDAC
in
water.

The
DDAC
concentrations
in
different
size
fresh
bodies
are
shown
in
Table
1:

Table
19.
Concentration
of
DDAC
(
ppm
and
ppb)
in
different
size
water
bodies
DDAC
In
Water
(
ppm)
DDAC
In
Water
(
ppb)
1
Acre
Foot
1233481.85
5
Liters
0.113791578
113.8
6
Acre
foot
7400891.13
2
Liters
0.018965263
19.0
12
Acre
foot
14801782.2
6
Liters
0.009482632
9.50
18
Acre
foot
22202673.4
Liters
0.006321754
6.30
24
Acre
foot
29603564.5
3
Liters
0.004741316
4.7
Page
26
of
33
The
maximum
amount
of
leachate
from
the
treated
wood
that
was
predicted
by
this
model
totaled
18.97
ppb.
The
lowest
predicted
amount
of
leachate
was
4.7
ppb
and
the
highest
amount
was
113.8
ppb.
LOC
values
for
fish
range
from
160
to
800
ppb,
for
green
algae
was
14
ppb
and
for
estuarine
invertebrates
was
48
ppb.
Freshwater
invertebrates
are
the
most
sensitive
aquatic
animals
to
DDAC
with
an
acute
LOC
of
34.5
ppb.

Conclusions:

Once­
through
Cooling
Tower
Use
Tier
I
once­
through
cooling
tower
modeling
indicates
that
DDAC
use
will
result
in
acute
and
chronic
risk
to
all
non­
endangered
and
endangered/
threatened
aquatic
organisms
at
all
dosages
modeled:
32
ppm
and
63
ppm
for
continuous
dosing
and
1000
ppm
and
1800
ppm
for
intermittent
dosing.

The
high
vs
medium
vs
low
water
flow
rate
is
based
on
size
of
the
facility.
Generally,
higher
flow
(
e.
g.,
>
1000
MGD)
would
use
more
chemical
than
smaller
facilities,
but
the
pattern
does
not
hold
true
across
the
board,
probably
because
model
input
values
are
based
on
different
receiving
water
("
reach")
data
for
individual
facilities.
This
model
uses
7Q10
rainfall
conditions,
which
is
essentially
the
worst­
case
drought
of
a
10
year
period.
Variables
such
as
stream
flow
rate
and
DDAC
dissipation,
degradation,
and
1/
2
life
were
not
considered
in
this
Tier
I
model
but
should
be
considered
in
higher
tier
modeling.
Field
monitoring
is
suggested
in
the
absence
of
higher
Tier
modeling.
Risk
mitigation
recommendations
should
be
based
on
dosing
method
(
e.
g.
intermittent
vs
continuous)
and
application
rate
instead
of
facility
size,
however,
risk
mitigation
is
not
recommended
at
this
time.

Wood
Treatment
Use
The
maximum
amount
of
leachate
from
treated
wood
per
the
Krahn
and
Strub,
1990
model
totaled
18.97
ppb.
The
lowest
predicted
amount
of
leachate
was
4.7
ppb
and
the
highest
amount
was
113.8
ppb.
Non­
endangered/
threatened
aquatic
species
(
fish
and
invertebrates)
are
not
expected
to
be
adversely
affected
­
acute
or
chronic
toxicity
­
based
on
LOCs
above.
Endangered/
threatened
fish
(
freshwater
warmwater
species)
are
not
expected
to
be
adversely
affected
by
the
wood
treatment
use.
However,
green
alga
non­
endangered/
threatened
species,
and
freshwater
fish
coldwater
species,
freshwater
and
marine
aquatic
invertebrates,
and
green
algae
endangered/
threatened
species
are
at
risk
from
the
wood
treatment
use.

Due
to
the
extreme
sensitivity
of
freshwater
and
marine
aquatic
invertebrates
to
DDAC,
methods
such
as
indoor
or
covered
wood
storage
and/
or
containment
of
runoff
water
via
berms
or
plastic
barriers
in
outdoor
storage
areas
are
suggested.
DDAC
is
tightly
adsorbed
to
clay
and
organic
matter
which
greatly
reduces
potential
for
DDAC
to
leach
downward
through
soil
to
groundwater,
and
will
serve
to
reduce
surface
runoff
as
well.
The
Tier
I
screening
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
Page
27
of
33
model
is
recommended
before
any
regulatory
action
is
taken
regarding
the
antisapstain
uses
of
DDAC.
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.

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
andronomus
listed
species,
or
the
United
States
Fish
and
Wildlife
Services
(
FWS)
for
listed
wildlife
and
freshwater
organisms,
if
they
are
proposing
an
"
action"
that
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.

For
certain
use
categories,
the
Agency
assumes
there
will
be
minimal
environmental
exposure,
and
only
a
minimal
toxicity
data
set
is
required
(
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,
Appendix
A,
Section
IIB,
pg.
81).
Chemicals
in
these
categories
therefore
do
not
undergo
a
full
screening­
level
risk
assessment,
and
are
considered
to
fall
under
a
Ano
effect@
determination
(
NE).
The
majority
of
DDAC
uses
are
spray
applications
to
indoor
surfaces,
truck
interiors,
kennels,
institutional
areas,
household
areas,
recirculating
cooling
towers,
evaporative
condensers,
pulp/
paper
mills,
swimming
pools
and
spas,
and
oil
field
mud
treatments
to
name
a
few
and
fall
into
this
category
for
the
following
reasons:
Page
28
of
33
1.
The
amount
that
will
actually
reach
the
environment
is
very
small
based
on
usage
data
and
use
patterns
(
no
homeowner/
residential
use
for
bathrooms)
and
containment
methods
(
retaining
ponds,
recirculation,
low
residual
upon
release).

2.
Breakdown
in
the
environment
and
via
sewage
treatment
is
rapid
and
well
documented
in
the
literature
(
See
Environmental
Fate
Chapter
for
more
detail).
The
agency
requires
the
following
label
statement:
"
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
authorities
are
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."
There
was
no
information
in
the
Sewage
Treatability
Database
on
DDAC.

DDAC
uses
that
have
potential
for
direct
release
into
the
environment
or
runoff
to
surface
waters
include
once­
through
cooling
tower
and
wood
treatment
uses
respectively.
These
uses
are
considered
to
be
representative
of
having
worst­
case
potential
for
impacting
the
environment.
Therefore,
these
sites
were
modeled.

The
"
best
case"
once­
through
cooling
tower
scenario
using
1/
2
the
maximum
recommended
label
dosage
intermittently
applied
in
a
low
water
flow
resulted
in
LOC
exceedances
for
all
aquatic
organisms
used
in
the
model,
including
freshwater
fish,
green
alga,
freshwater
invertebrates,
and
marine
invertebrates.
The
agency
is
not
aware
of
any
endangered
or
threatened
green
algae.
Because
DDAC
is
rapidly
adsorbed
to
organic
materials
and
clay,
impacts
to
aquatic
organisms
may
be
less
than
modeled.
Aerobic
aquatic
metabolism
study
on
DDAC
(
MRID#
422538­
03)
provides
a
sediment
half­
life
of
60
years.
There
is
a
potential
for
sediment
concentrations
to
reach
toxic
levels
over
time
(
aerobic
soil
metabolism
half­
life
of
2.8
years,
MRID#
422538­
01).
The
once­
through
cooling
tower
model
does
not
account
for
degradation
and
therefore,
further
assessment
is
required
prior
to
making
an
agency
endangered
species
determination.

Endangered/
threatened
coldwater
fish
species,
marine
and
freshwater
invertebrates,
and
green
algae
species
are
expected
to
be
adversely
affected
by
the
wood
treatment
use.
Impacts
from
the
wood
treatment
use
are
not
expected
to
occur
as
long
as
precautions
are
taken
to
prevent
leaching
when
wood
is
stored
outdoors.
Using
Tier
I
screening
modeling
to
assess
potential
exposure
from
antisapstain
wood
preservation
uses
of
DDAC,
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
DDAC.
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
Page
29
of
33
is
stored
outdoors.
Due
to
these
circumstances,
the
Agency
defers
making
a
determination
for
the
antisapstain
uses
of
DDAC
until
additional
data
and
modeling
refinements
are
available.
At
that
time,
the
environmental
exposure
assessment
of
the
antisapstain
use
of
DDAC
will
be
revised,
and
the
risks
to
Listed
Species
will
be
reconsidered.

IV.
Confirmatory
Data
Required
1.
Nontarget
Plant
Phytotoxicity
Study
is
Required:
850.4225
(
seedling
emergence
test
using
rice).

2.
Acute
Eastern
Oyster
embryo
larvae
study
is
required:
850.1055
3.
Chronic
Daphnia
magna
is
required:
850.1300
4.
Monitoring/
Tier
II
modeling
of
once­
through
cooling
tower
and
antisapstain
uses
to
establish
EEC's
for
risk
assessment.

IV.
Label
Hazard
Statements
for
Terrestrial
and
Aquatic
Organisms
and
Use
Recommendations
DDAC
labels
must
state:

"
This
pesticide
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
authorities
are
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."

Wood
treatment
labels
must
state:
"
Treated
lumber
must
not
be
stored
outdoors
without
precautions
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."
Page
30
of
33
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22
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Lab.
(
1973)
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22)
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bobwhite
quail
and
mallard
duck.

ACC#
225596:
Cannon
Lab.
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1976)
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hour
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study
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22
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ACC#
225596:
Cannon
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1977)
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oral
LD50
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22
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48
hour
EC50
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96
hour
LC50
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14
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Bardac
22)
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oyster
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and
straight­
hinge
larvae.

ACC#
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(
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14
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ACC#
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(
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14
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ACC#
258798:
Fink,
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Fink,
R.
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ACC#
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01:
Henck,
J.
H.
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1986)
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01:
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C.
(
1986)
Acute
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12­
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01,
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02,
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03:
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C.
(
1987)
Acute
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Maquat
MQ
416M
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MRID#
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01:
LeLievre,
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a
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MRID#
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LeLievre,
M.
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(
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Evaluation
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MRID#
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LeLievre,
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MRID#
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LeLievre,
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static
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MRID#
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MRID#
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Long,
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MRID#
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02:
Long,
R.
D.,
Hoxter,
K.
A.
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Smith,
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J.
(
1991b)
Didecyldimethylammoniumchloride:
A
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study
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the
mallard.

MRID#
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03:
Campbell,
S.,
Hoxter,
K.
A.,
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G.
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(
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MRID#
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Didecyldimethylammoniumchloride
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A
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Wildlife
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MRID#
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R.
(
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A
96­
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ADDITIONAL
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Elphick,
J.
R.,
Potter,
A.,
Chao,
E.
and
Zak,
B.
(
1999)
Acute
toxicity
of
the
antisapstain
chemicals
DDAC
and
IPBC,
alone
and
in
combination,
to
rainbow
trout
(
Oncorhynchus
mykiss).
Water
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33(
10):
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2414.

Bennett,
W.
R.
and
Farrell,
A.
P.
(
1998)
Acute
toxicity
testing
with
Juvenile
white
sturgeon
(
Acipenser
transmontanus).
Water
Qual.
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33(
1):
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110.

Tatarazako,
N.,
Yamamota,
K.
and
Iwasaki,
K.
(
2000)
Subacute
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