1
of
17
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
April
13,
2006
MEMORANDUM
SUBJECT:
Environmental
Fate
Assessment
of
Didecyl
dimethyl
ammonium
chloride
(
DDAC)
for
the
Reregistration
Eligibility
Decision
(
RED)
Document
Case
No.:
3003
DP
Barcode:
323303
FROM:
Srinivas
Gowda,
Microbiologist/
Chemist
Risk
Assessment
and
Science
Support
Branch
(
RASSB)
Antimicrobials
Division
(
7510C)

TO:
Mark
Hartman,
Branch
Chief
Benjamin
Chambliss,
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:
Siroos
Mostaghimi,
Acting
Team
Leader,
Team
one
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
Fate
Science
Chapter
and
Fate
Assessment
on
DDAC
is
submitted
for
Reregistration
Eligibility
Decision
(
RED).
2
of
17
1­
DECANAMINIUM,
N­
DECYL­
N,
N­
DIMETHYL­,
CHLORIDE
(
DDAC)
ENVIRONMENTAL
FATE
SCIENCE
CHAPTER
EXECUTIVE
SUMMARY
DDAC
is
used
primarily
as
a
disinfectant,
sanitizer,
or
as
a
microbiocide/
microbiostat.
It
also
serves
as
an
algaecide,
bacteriocide/
bacteriostat,
fungicide/
fungistat,
insecticide,
miticide,
virucide,
and
tuberculocide.
Use
sites
for
DDAC
include
agricultural
premises
and
equipment,
food
handling,
commercial,
industrial
and
institutional
settings,
residential
areas
or
areas
of
public
access,
pets
and
kennels,
medical
facilities,
swimming
pools,
aquatic
areas,
and
industrial
water
systems.
DDAC
is
also
used
as
a
wood
preservative.
As
an
agricultural
pesticide,
DDAC
is
used
for
ornamental
plants,
shrubs,
and
vines.
Some
of
the
required
guideline
studies
for
an
environmental
fate
assessment
have
been
submitted.
The
Agency
is
using
these
environmental
fate
studies
for
fate
assessment
of
DDAC
to
fulfill
the
reregistration
requirements.
However,
field
dissipation
and
aquatic
field
dissipation
studies
as
well
as
a
long­
term
study
on
accumulation
on
soils
are
still
needed.

DDAC
has
been
shown
to
be
hydrolytically
stable
under
abiotic
and
buffered
conditions
over
the
pH
5­
9
range.
DDAC
is
stable
to
photodegradation
in
pH
7
buffered
aqueous
solutions;
even
in
the
presence
of
a
photosensitizer
(
acetone),
degradation
is
minimal.
DDAC
is
not
subject
to
photodegradation
in
soil.

Aquatic
metabolism
studies
under
aerobic
and
anaerobic
conditions
indicate
that
DDAC
is
stable
to
microbial
degradation.
The
calculated
aerobic
and
anaerobic
half­
lives
of
14C­
DDAC
in
flooded
river
water
are
180
days
and
261
days,
respectively.
Similarly,
DDAC
was
found
to
be
stable
with
very
little
degradation
in
aerobic
soils
during
a
year­
long
metabolism
study.
However,
a
report
on
the
biodegradability
of
DDAC
prepared
by
the
Registrant
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.
According
to
this
report,
DDAC
is
biodegradable
and
environmentally
acceptable.
This
report
was
based
on
information
from
the
open
literature,
unpublished
sources,
and
meeting
proceedings
and
has
not
been
reviewed
by
the
Agency.

DDAC
is
immobile
in
soil.
A
soil
mobility
study
reviewed
by
the
Agency
shows
that
DDAC
has
a
strong
tendency
to
bind
to
sediment/
soil
with
Freundlich
Kads
values
of
1,095,
8,179,
32,791,
and
30,851
in
sand,
sandy
loam,
silty
clay
loam,
and
silt
loam
soils,
respectively.
Because
of
its
strong
adsorption
to
soils,
DDAC
is
not
expected
to
contaminate
surface
and
ground
waters.

Bioaccumulation
of
DDAC
in
freshwater
fish
is
not
likely
to
occur.
Mean
steady
state
bioconcentration
factors
for
DDAC
were
determined
to
be
38X,
140X,
and
81X
in
the
edible,
nonedible,
and
whole
body
fish
tissue,
respectively.
DDAC
is
not
expected
to
pose
a
concern
for
bioconcentration
in
aquatic
organisms.
3
of
17
Information
on
the
aqueous
availability
of
DDAC
from
wood
indicates
that
the
use
of
DDAC
as
a
wood
preservative
may
result
in
minimal
releases
to
the
environment.

I.
Environmental
Fate
Assessment
A.
Abiotic
In
a
hydrolysis
study
conducted
under
abiotic
and
buffered
conditions,
methyl­
labeled
14C­
didecyl
dimethyl
ammonium
chloride
(
DDAC),
at
concentrations
of
8.47
to
8.69
µ
g/
ml,
was
stable
in
sterile
aqueous
buffer
solutions
adjusted
to
pH
5
(
0.2
M
acetate),
pH
7
[
tris(
hydroxymethyl)
aminomethane­
(
TRIS)],
pH
7
[
N­
2­
hydroxyethyl­
piperazine­
N'­
2­
ethanesulfonic
acid
(
HEPES)],
and
pH
9
(
0.2
M
borate)
that
were
incubated
in
darkness
at
25EC
±
1EC
for
30
days.
Of
the
recovered
radioactivity
throughout
the
30­
day
monitoring
period,
DDAC
residues
comprised
92.0
to
95.9%
(
pH
5),
89.9
to
94.5%
(
pH
7,
HEPES),
93.1
to
97.9%
(
pH
7,
TRIS),
and
92.0
to
96.7%
(
pH
9).
The
calculated
half­
lives
for
DDAC
(
extrapolated
beyond
the
experimental
timeframe)
were
368
days
at
pH
5,
194
days
at
pH
7
(
TRIS),
175
days
at
pH
7
(
HEPES),
and
506
days
at
pH
9.
The
hydrolysis
guideline
requirements
(
OPP
161­
1)
have
been
fulfilled
by
this
study
(
MRID
No.
411758­
01).

The
photodegradation
potential
of
DDAC
was
investigated
in
sensitized
and
nonsensitized
buffer
solutions
adjusted
to
pH
7
(
0.2
M
TRIS).
Methyl­
labeled
14C­
didecyl
dimethyl
ammonium
chloride
(
DDAC),
at
a
concentration
of
8.58
µ
g/
ml,
was
relatively
stable
in
nonsensitized
sterile
aqueous
buffer
solutions
that
were
continuously
irradiated
with
a
xenon
light
source
at
25EC
±
1EC
for
30
days.
DDAC
concentrations
ranged
from
91.2
to
103%
of
the
applied
radioactivity
with
no
discernible
pattern
of
decline.
In
the
dark
controls,
DDAC
concentrations
ranged
from
93.5
to
100%
of
the
applied
radioactivity
throughout
the
30­
day
monitoring
period.
In
a
similar
experiment
using
acetone­
sensitized
buffer
solutions,
DDAC
was
also
found
to
be
relatively
stable.
DDAC
declined
from
100%
of
the
applied
radioactivity
immediately
post
treatment
to
93.1%
at
the
end
of
30­
day
monitoring
period.
DDAC
concentrations
ranged
from
96.2
to
102
percent
of
the
applied
radioactivity
with
no
discernible
pattern
of
decline
in
the
dark
sensitized
controls.
The
calculated
half­
life
of
DDAC
(
extrapolated
beyond
the
experimental
timeframe)
was
227
days
based
on
results
for
the
sensitized
irradiated
solutions.
The
photodegradation
in
water
guideline
requirements
(
OPP
161­
2)
have
been
fulfilled
by
this
study
(
MRID
411758­
02).
4
of
17
B.
Biotic
The
aerobic
aquatic
biotransformation
of
DDAC
was
studied
in
a
pond
water/
sediment
system
(
water
­
pH
of
8.7,
sediment
­
pH
of
8,
sandy
loam
texture,
organic
carbon
content
of
1.6%)
from
Northwood,
North
Dakota
treated
with
methyl­
labeled
[
14C]
DDAC
at
a
nominal
concentration
of
10
parts
per
million
(
ppm).
The
treated
water/
sediment
system
was
incubated
in
the
dark
for
365
days
at
25EC.
The
calculated
half­
lives
of
14C­
DDAC
in
water,
sediment,
and
in
the
entire
system
were
180
days,
22,706
days
(
60.5
years),
and
8,366
days
(
22.9
years),
respectively.
At
test
termination,
101%
of
the
applied
radioactivity
was
partitioned
from
water
to
sediment.
Transformation
products
were
not
present
in
any
significant
amounts
in
the
water
or
sediment.
The
aerobic
aquatic
metabolism
guideline
requirements
(
OPP
162­
4)
have
been
fulfilled
by
this
study
(
MRID
422538­
03).

A
study
of
the
anaerobic
aquatic
metabolism
of
DDAC
in
lake
water
and
sediment
was
also
conducted.
Samples
of
lake
water
and
sediment
were
incubated
at
25
EC
in
a
dark
environment
for
365
days.
In
this
study,
DDAC
was
shown
to
be
stable
to
microbial
degradation.
The
calculated
half­
lives,
based
on
first­
order
degradations
of
14C­
DDAC
in
anaerobic
water,
sediment
and
in
the
entire
system
were
261,
4,594,
and
6,217
days,
respectively.
Transformation
products
were
not
present
in
any
significant
amounts
in
the
water
or
sediment.
This
study
satisfies
the
anaerobic
aquatic
metabolism
guideline
requirements
(
OPP
162­
3)
(
MRID
No.
422538­
02).

The
aerobic
soil
metabolism
of
DDAC
was
investigated
in
a
sandy
loam
soil,
which
is
a
representative
agricultural
soil.
The
soil
was
treated
with
[
14C]
DDAC
to
achieve
a
concentration
of
10
ppm
and
incubated
in
darkness
at
25EC
for
up
to
365
days.
DDAC
was
found
to
be
stable
with
very
little
degradation
during
the
year­
long
study.
Transformation
products
were
not
present
in
any
significant
amounts.
The
calculated
half­
life
for
degradation
was
1,048
days.
This
study
is
acceptable
and
satisfies
guidelines
(
OPP
162­
1)
for
aerobic
soil
metabolism
(
MRID
No
422538­
01).

A
review
of
information
from
the
open
literature,
unpublished
sources
and
meeting
proceedings
prepared
by
the
Registrant
indicates
that
DDAC
is
aerobically
biodegradable.
The
report
author
noted
that
the
aerobic
and
anaerobic
aquatic
metabolism
studies
conducted
on
DDAC
were
designed
to
assess
the
environmental
fate
of
DDAC
based
on
outdoor
applications
of
agricultural
chemicals
but
not
the
direct
biodegradability
potential
of
DDAC
as
a
result
of
its
use
as
an
antimicrobial.
Other
limitations
of
the
tests
were
noted
such
as
loss
of
microbial
activity
during
air
drying
of
soil
material,
limited
gas
exchange
in
the
aerobic
test,
and
the
use
of
unacclimated
microbial
systems.
According
to
this
report,
the
degree
of
DDAC's
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.
A
mechanism
of
biodegradation
for
DDAC
in
which
several
bacterial
species
are
needed
for
ultimate
biodegradation
of
this
compound
is
also
described.

In
an
adsorption/
desorption
study
reviewed
by
the
Agency,
DDAC
was
found
to
be
immobile
in
four
representative
agricultural
soils
(
sand,
sandy
loam,
silt
clay
loam,
and
silt
5
of
17
loam).
Freundlich
Kads
values
were
1,095
for
the
sand,
8,179
for
the
sandy
loam,
32,791
for
the
silty
clay
loam,
and
30,851
for
the
silt
loam
soils.
Respective
Koc
values
were
437,805,
908,757,
1,599,564,
and
1,469,081.
Freundlich
Kdes
values
were
591
for
the
sand
soil,
2,074
for
the
sandy
loam
soil,
8,309
for
the
silty
clay
loam
soil,
and
7,714
for
the
silt
loam
soil.
Respective
Koc
values
were
236,473,
230,498,
405,328,
and
367334.
This
study
(
MRID
No.
413853­
01)
partially
fulfills
the
adsorption/
desorption
data
requirements
for
DDAC
(
OPP
163­
1)
by
providing
information
on
the
mobility
(
batch
equilibrium)
of
unaged
14C­
DDAC
in
sodium
azide­
sterilized
sand,
sandy
loam,
silty
clay
loam,
and
silt
loam
soils.
However,
additional
data
are
required
on
the
mobility
of
aged
14C­
DDAC
residues
in
soil.

A
46­
day
study
(
28­
day
bioconcentration
and
18­
day
depuration
period)
was
conducted
to
evaluate
the
bioconcentration
of
DDAC
in
bluegill
sunfish
under
flow­
through
aquarium
conditions
(
MRID
No.
458341­
01).
In
this
study,
the
levels
of
14C
residues
in
the
edible,
nonedible
and
whole
body
fish
tissue
reached
steady
state
by
day
10
of
exposure.
Mean
steady
state
bioconcentration
factors
for
DDAC
were
38X,
81X,
and
140X
in
the
edible
tissue,
whole
body
fish
tissue,
and
nonedible
tissue,
respectively.
These
bioconcentration
factors
are
considered
relatively
low
and
indicate
that
DDAC
would
not
be
expected
to
bioaccumulate
in
fish
tissue.
By
day
14
of
the
depuration
period,
57%,
67%,
and
71%
of
the
14C
residues
present
on
the
last
day
of
exposure
in
the
edible,
whole
body,
and
nonedible
tissue,
respectively,
had
been
eliminated.
DDAC
was
found
to
bind
significantly
to
the
non­
edible
segments
of
the
bluegill,
especially
the
skin
and
scales.
14C
residue
levels
were
approximately
2
to
6
times
higher
in
skin
tissue
than
those
observed
for
the
corresponding
edible
tissue.
The
half­
life
of
DDAC
was
determined
to
be
between
7
and
14
days
of
depuration.
Study
results
also
indicated
that
the
half­
life
of
DDAC
in
edible
tissue
is
significantly
shorter
than
that
of
the
nonedible
segments.
The
Agency
noted
that
the
concentration
of
DDAC
in
the
treatment
aquarium
was
continuously
above
nominal
and
was
not
consistently
maintained
within
±
20%
of
the
mean
measured
value.
In
addition,
the
temperatures
ranged
between
17­
18
°
C,
which
is
below
the
recommended
temperature
of
20­
25
°
C.
However,
the
study
was
found
by
the
Agency
to
be
acceptable
and
provided
useful
information
on
the
bioaccumulation
of
DDAC
residues
in
bluegill
sunfish.
It
satisfies
the
bioaccumulation
in
fish
data
requirements
for
DDAC
(
OPP
165­
4/
850.1730).

A
photolysis
study
was
conducted
with
DDAC
on
soil
treated
at
a
nominal
concentration
of
10
ppm.
The
study
consisted
of
two
test
systems:
an
exposed
test
system
that
was
continuously
irradiated
with
a
xenon
arc
light
source
for
30
days
and
a
non­
exposed
test
system.
In
the
exposed
system,
the
photolysis
rate
constant
and
half­
life
of
DDAC
were
reported
as
5.26
x
10­
3
days­
1
and
132
days,
respectively.
The
photolysis
rate
constant
and
half­
life
of
DDAC
in
the
non­
exposed
system
were
determined
to
be
4.11
x
10­
3
days­
1
and
169
days,
respectively.
This
study
is
acceptable
and
meets
guidelines
for
the
fulfillment
of
data
requirements
for
DDAC
on
photodegradation
on
soil
(
OPP
161­
3)
(
MRID
No.
424807­
01).

An
aqueous
availability
study
(
MRID
No.
455243­
05),
performed
according
to
the
American
Wood
Preservers'
Association
Standard,
Method
E11­
97,
evaluated
the
leachability
of
didecylmethyl
ammonium
carbonate
(
DDACarb),
a
related
compound,
from
treated
wood.
Wood
samples
were
vacuum­
treated
with
0.85
percent
(
0.5X
retention
level),
1.7
percent
(
1X),
6
of
17
and
3.4
percent
(
2X)
of
DDACarb,
and
placed
in
deionized
water
for
14
days.
Leachate
was
collected
from
the
sampling
unit
at
intervals
of
6,
24,
and
48
hours,
and
4,
6,
8,
10,
12,
and
14
days
following
the
start
of
the
leaching
period.
The
corrected
amount
of
DDACarb
recovered
from
the
leachate
ranged
from
186.1
µ
g
to
764.7
µ
g
(
0.5X
retention
level),
from
218.9
µ
g
to
1152.9
µ
g
(
1X),
and
from
446.2
µ
g
to
2101.1
µ
g
(
2X).
The
total
recovery
from
the
leachate
over
the
14­
day
period
was
3464.7
µ
g,
4483.0
µ
g
and
7444.7
µ
g
for
the
0.5X,
1X
and
2X
retention
levels,
respectively.
7
of
17
APPENDIX
Environmental
Fate
Data
for
DDAC
A.
Environmental
Fate
Guideline
Studies
1.
Hydrolysis
(
OPP
Guideline
Number
161­
1,
MRID
No.
411758­
01)

This
hydrolysis
study
was
reviewed
by
the
Agency
and
was
found
acceptable.
The
hydrolysis
data
requirements
for
DDAC
have
been
fulfilled.

In
this
study,
methyl­
labeled
[
14C]
DDAC
(
didecyldimethylammonium
chloride,
radiochemical
purity
99.2%,
specific
activity
9.01
mCi/
mmol),
in
deionized,
sterile­
filtered
water,
was
added
to
sterile
pH
5
(
acetate),
pH
7
(
TRIS),
pH
7
(
HEPES)
and
pH
9
(
borate)
aqueous
buffer
solutions
at
concentrations
of
8.47­
8.69
µ
g/
ml.
Aliquots
of
the
treated
buffer
solutions
were
added
to
sterile,
foil­
covered
culture
tubes
and
incubated
in
the
dark
at
25
±
1EC
for
30
days.
Samples
were
removed
for
analysis
at
0,
4,
7,
14,
22,
and
30
days
post
treatment.

At
each
sampling
interval,
duplicate
aliquots
of
the
buffer
solutions
were
analyzed
for
total
radioactivity
by
liquid
scintillation
counting
(
LSC).
An
additional
aliquot
of
the
test
solution
was
analyzed
by
one­
dimensional
TLC
on
silica
gel
plates
developed
in
chloroform:
methanol:
formic
acid
(
60:
40:
2,
v:
v:
v).
Radioscanning
was
used
to
locate
and
quantify
radioactive
areas.
TLC
plates
from
the
0­
and
30­
day
sampling
intervals
were
analyzed
by
autoradiography.

Study
results
indicate
that
methyl­
labeled
[
14C]
DDAC
was
relatively
stable
in
sterile
pH
5,
pH
7
(
TRIS
and
HEPES),
and
pH
9
buffer
solutions
incubated
in
the
dark
at
25
±
1EC
for
30
days.
In
the
pH
5
buffer
solution,
the
parent
was
present
at
92.0%
of
the
recovered
radioactivity
at
30
days
posttreatment
(
range
during
the
study:
92.0
­
95.9%
of
the
recovered
radioactivity);
total
[
14C]
DDAC
residues
during
the
study
ranged
from
8.22
µ
g/
mL
to
8.95
µ
g
/
ml
with
no
discernible
pattern.
The
parent
comprised
89.9
­
94.5%
and
93.1
­
97.9%
of
the
recovered
radioactivity
in
the
pH
7(
HEPES)
and
pH
7
(
TRIS)
buffer
solutions,
respectively.
Total
[
14C]
DDAC
residues
during
the
study
ranged
from
7.93
µ
g
/
ml
to
9.02
µ
g
/
ml
in
the
pH
7
(
HEPES)
buffer
solution
and
from
7.83
µ
g
/
ml
to
8.90
µ
g
/
ml
in
the
pH
7
(
TRIS)
buffer
solution
.
In
the
pH
9
buffer
solution,
total
[
14C]
DDAC
residues
ranged
from
8.00
µ
g
/
ml
to
8.67
µ
g
/
ml
with
no
discernible
pattern;
parent
[
14C]
DDAC
comprised
92.0
­
96.7%
of
the
recovered
radioactivity.
The
material
balances
were
95.6
­
104%
for
the
pH
5
solution,
93.6
­
106%
for
the
pH
7
(
HEPES)
solution,
90.1
­
102%
for
the
pH
7
(
TRIS)
solution,
and
92.3
­
100%
for
the
pH
9
solution.

The
calculated
half­
lives
for
[
14C]
DDAC
were
368
days
at
pH
5,
194
days
at
pH
7
(
TRIS),
175
days
at
pH
7
(
HEPES),
and
506
days
at
pH
9.
It
was
noted
that
these
statistical
estimates
are
of
limited
value
because
the
calculations
involve
extrapolation
considerably
beyond
the
experimental
time
limits
of
the
study.
8
of
17
TLC
analysis
of
the
pH
7
(
HEPES)
solution
at
day
30
indicated
a
slight
decrease
(
approximately
10%)
in
the
size
of
the
parent
peak;
the
material
appeared
to
form
a
shoulder
on
the
parent
peak.
However,
given
the
apparent
half­
life
of
175
days
and
a
low
correlation
coefficient
(
r2
=
0.575),
the
authors
concluded
that
this
observation
did
not
indicate
significant
degradation.

2.
Photodegradation
in
Water
(
OPP
Guideline
No.
161­
2,
MRID
No.
411758­
02)

This
photodegradation
study
was
reviewed
by
the
Agency
and
was
found
to
be
acceptable.
The
photodegradation
in
water
data
requirements
for
DDAC
have
been
satisfied.

In
this
study,
methyl­
labeled
[
14C]
DDAC
(
didecyldimethylammonium
chloride,
radiochemical
purity
 
98.5%,
specific
activity
9.01
mCi/
mmol),
in
deionized
water,
was
added
to
sterile
pH
7
(
TRIS)
buffer
solution
at
a
concentration
of
8.58
µ
g/
ml.
[
14C]
DDAC
was
also
added
at
a
concentration
of
8.59
µ
g
/
ml
to
a
sterile
pH
7
(
TRIS)
buffer
solution
that
had
been
photosensitized
with
1%
acetone.
Aliquots
of
the
treated
solutions
were
transferred
to
borosilicate
glass
culture
tubes
with
Teflon­
lined
screw
tops.
Some
of
the
vials
containing
the
test
solutions
were
covered
with
aluminum
foil
and
stored
inside
a
closed
box
(
dark
control
samples).
The
box
was
placed
along
with
unwrapped
tubes
(
12)
in
a
photolysis
apparatus.
A
xenon
lamp
was
used
to
continuously
irradiate
the
samples
for
30
days.
The
temperature
in
the
photolysis
chamber
was
maintained
at
25
±
1EC.

Aliquots
of
the
test
solutions
were
analyzed
immediately
post
treatment
and
duplicate
samples
of
irradiated
and
dark
control
solutions
were
removed
for
analysis
at
1.03,
2.02,
7.03,
14.0,
21.0,
and
29.9
days
post
treatment.
At
each
sampling
interval,
duplicate
aliquots
of
irradiated
and
dark
control
solutions
were
analyzed
for
total
radioactivity
by
liquid
scintillation
counting
(
LSC).
Additional
aliquots
of
each
test
solution
were
analyzed
by
one­
dimensional
TLC
on
silica
gel
plates
developed
in
chloroform:
methanol:
formic
acid
(
60:
40:
2,
v:
v:
v).
Radioactive
areas
were
located
and
quantified
by
radioscanning.
In
addition,
TLC
plates
from
the
0­
and
30­
day
sampling
intervals
were
autoradiographed.
The
volatilization
of
[
14C]
residues
from
the
irradiated
and
dark
control
samples
was
also
measured.

Methyl­
labeled
[
14C]
DDAC,
at
a
concentration
of
8.58
µ
g/
ml,
was
relatively
stable
in
nonsensitized
aqueous
buffer
solution
(
pH
7)
that
was
continuously
irradiated
with
a
xenon
light
source
at
25EC
±
1EC
for
30
days.
In
the
irradiated
samples,
[
14C]
DDAC
was
present
at
100%
of
the
applied
radioactivity
immediately
post
treatment
and
ranged
from
91.2
to
103%
of
the
applied
radioactivity
throughout
the
study
period
(
1.03
 
29.9
days).
[
14C]
DDAC
was
93.5­
98.9%
of
the
applied
radioactivity
from
1.03
 
29.9
days
and
was
present
at
100%
of
the
applied
radioactivity
immediately
post
treatment
in
the
dark
control
samples.

In
the
irradiated
sensitized
samples,
[
14C]
DDAC
was
present
at
100%
of
the
applied
radioactivity
immediately
post
treatment
and
declined
to
93.1%
at
29.9
days.
An
unidentified
degradate
was
detected,
but
not
quantified.
In
the
dark
controls,
[
14C]
DDAC
was
100%
of
the
applied
radioactivity
immediately
post
treatment
and
96.2­
102%
of
the
applied
radioactivity
from
1.03
 
29.9
days.
The
calculated
photolytic
half­
life
was
227
days.
9
of
17
Material
balance
ranged
from
90.4
to
102%.
Results
of
the
volatility
experiments
indicated
little
or
no
volatilization
of
[
14C]
DDAC
from
the
test
solutions.

3.
Aerobic
Soil
Metabolism
(
OPP
Guideline
No.
162­
1,
MRID
No.
422538­
01)

This
aerobic
soil
metabolism
study
was
reviewed
by
the
Agency
and
found
to
be
acceptable.
The
study
meets
guidelines
for
the
fulfillment
of
data
requirements
for
DDAC
on
aerobic
soil
metabolism.
However,
the
Agency
stated
that
the
Registrant
must
provide
evidence
that
aerobic
conditions
were
maintained
throughout
the
experiment.

In
this
study,
samples
of
sandy
loam
soil
(
collected
from
Northwood,
North
Dakota,
78%
sand,
10%
silt,
12%
clay,
1.8%
organic
carbon,
pH
6.3,
CEC
0.7
meq/
100
g)
were
treated
with
methyl­
labeled
[
14C]
DDAC
(
didecyldimethylammonium
chloride,
radiochemical
purity
90%,
specific
activity
9.01
mCi/
mmol),
at
a
nominal
concentration
of
10
parts
per
million
(
ppm).
The
treated
soil
samples
were
incubated
in
darkness
at
24­
26EC
for
up
to
365
days;
soil
moisture
levels
were
maintained
between
70%
and
75%
of
field
moisture
capacity
by
the
addition
of
water
as
needed.
The
test
system
consisted
of
a
standard
tall
form
3,000
ml
resin­
pot
as
the
incubation
vessel
and
included
an
ethylene
glycol
trap,
a
sulfuric
acid
trap
and
two
potassium
hydroxide
traps
vessels
for
trapping
CO2
and
volatile
organics.
Samples
were
analysed
at
0,
1,
3,
7,
14,
31,
61,
92,
123,
182,
273,
and
365
days
of
incubation.
The
soil
samples
were
extracted
with
30
ml
of
80:
20
(
v:
v)
dimethylformamide:
acetic
acid
and
then
shaken
for
1
hour,
followed
by
centrifugation
for
10
minutes.
Total
radioactivity
in
the
samples
was
determined
by
liquid
scintillation
counting
(
LSC).
Quantification
and
identification
of
the
14C­
DDAC
residues
was
performed
using
TLC
and/
or
HPLC.

Material
balance
averaged
100.5
±
4.1%
of
the
applied
amount.
The
concentration
of
the
parent
compound
decreased
from
a
mean
of
93.7%
of
the
applied
amount
at
day
0,
to
a
mean
of
72.85%
of
the
applied
amount
at
the
end
of
the
study
period.
However,
no
biotransformation
of
the
parent
compound
was
reported.
The
calculated
half­
life
of
14C­
DDAC
in
aerobic
soil
was
1,048
days.

Extractable
14C­
residues
decreased
from
a
mean
of
98.55%
of
the
applied
amount
at
day
0
to
a
mean
of
74.87%
of
the
applied
amount
at
the
end
of
study
period.
Non­
extractable
14Cresidues
increased
from
a
mean
of
1.45%
of
the
applied
amount
at
day
0
to
a
mean
of
17.74%
of
the
applied
at
the
end
of
the
incubation
period.
At
study
termination,
an
average
of
1.95%
of
the
applied
radioactivity
was
present
as
volatile
organics.
CO2
was
not
present
in
any
significant
amount.
Transformation
products
were
not
present
in
any
significant
amounts
in
the
water
or
sediment.

4.
Anaerobic
Aquatic
Metabolism
(
OPP
Guideline
No.
162­
3,
MRID
No.
422538­
02)

This
anaerobic
aquatic
metabolism
study
was
reviewed
by
the
Agency
and
was
found
acceptable.
It
fulfills
the
anaerobic
aquatic
metabolism
data
requirement
for
DDAC;
however
10
of
17
the
Agency
noted
that
the
Registrant
must
submit
information
describing
how
anaerobic
conditions
were
assured
and
maintained.

The
anaerobic
aquatic
metabolism
of
DDAC
was
studied
using
subsamples
(
10
g
dry
weight)
of
sieved
(
2
mm)
sandy
loam
sediment
from
Northwood,
ND
(
62%
sand,
22%
silt,
16%
clay,
pH
8,
CEC
16.3
meq/
100g,
organic
carbon
1.6%)
flooded
with
20
ml
of
lake
water
from
the
same
site
(
pH
8.1).
The
sediment
water
samples
were
treated
with
a
sufficient
amount
of
methyl­
labeled
[
14C]
DDAC
(
didecyldimethylammonium
chloride,
radiochemical
purity
90%,
specific
activity
9.01
mCi/
mmol),
to
achieve
a
nominal
concentration
of
10
parts
per
million
(
ppm).
The
test
tubes
were
incubated
in
the
dark
at
a
temperature
of
25
°
C
for
365
days;
the
test
system
consisted
of
a
standard
tall
form
3000­
ml
resin­
pot
as
the
metabolism
vessel.
An
ethylene
glycol
trap,
a
sulfuric
acid
trap
and
two
potassium
hydroxide
traps
were
attached
for
the
collection
of
carbon
dioxide
(
CO2)
and
volatile
organic
compounds.
Sediment,
water
and
volatile
traps
were
sampled
at
0,
1,
3,
7,
14,
31,
61,
92,
123,
182,
273,
and
365
days
of
incubation.
Volatile
traps
were
also
sampled
at
151,
212,
243,
304
and
335
days
of
incubation.

At
each
sampling
interval,
sediment:
water
samples
were
centrifuged
and
the
aqueous
phase
decanted.
The
water
samples
were
extracted
via
mixing
with
an
equal
volume
of
80:
20
(
v:
v)
dimethylformamide:
acetic
acid
and
then
run
through
a
0.2­
F
filter
to
remove
any
suspended
solids.
The
sediment
samples
were
extracted
with
30
ml
of
80:
20
(
v:
v)
dimethylformamide:
acetic
acid
and
then
shaken
for
1
hour,
followed
by
centrifugation
for
10
minutes.
Quantification
and
identification
of
the
14C­
DDAC
residues
was
performed
using
TLC
and/
or
HLPC.

Material
balance
averaged
103.1
±
3.5
%
of
the
applied
amount
for
the
year­
long
study.
The
test
conditions
outlined
in
the
study
protocol
were
maintained
throughout
the
study.
Extractable
[
14C]
residues
in
sediment
increased
from
a
mean
of
84.87
%
at
day
0,
to
a
mean
of
92.22
%
of
the
applied
amount,
at
study
termination.
Non­
extractable
[
14C]
residues
in
sediment
decreased
from
a
mean
of
12.21
%
at
day
0,
to
a
mean
of
10.39
%
of
the
applied
amount,
at
study
termination.
At
the
end
of
the
study,
0.30
%
of
the
applied
radioactivity
was
present
as
volatile
compounds,
and
this
activity
was
later
confirmed
to
be
14C­
carbon
dioxide
via
precipitation
with
barium
chloride.

The
concentration
of
14C­
DDAC
in
water
decreased
from
a
mean
of
100
%
at
day
0
to
a
mean
of
68.65
%
of
the
applied
amount,
at
study
termination.
The
concentration
of
14C­
DDAC
in
the
sediment
increased
from
a
mean
of
93.85
%
at
day
0
to
a
mean
of
97.45
%
of
the
applied
amount,
at
the
end
of
the
study
period.
The
study
authors
noted
that
transformation
products
were
not
present
in
any
significant
amounts
in
the
water
or
sediment.

The
calculated
half­
life
of
14C­
DDAC
(
for
the
entire
system),
based
on
a
first­
order
degradation,
was
6,218
days.
The
Agency's
calculated
half­
lives,
based
on
first­
order
degradations
of
14C­
DDAC
in
anaerobic
water,
sediment
and
in
the
entire
system
were
261,
4,594,
and
6,217
days,
respectively.
No
biotransformation
of
the
parent
compound
was
reported.
11
of
17
5.
Aerobic
Aquatic
Metabolism
(
OPP
Guideline
No.
162­
4,
MRID
No.
422538­
03)

This
aerobic
aquatic
metabolism
study
was
reviewed
by
the
Agency
and
was
found
to
be
acceptable.
It
satisfies
the
aerobic
aquatic
metabolism
data
requirements
for
DDAC.
However,
the
Agency
noted
that
the
Registrant
must
submit
information
describing
how
aerobic
conditions
were
assured
and
maintained.

In
this
study,
subsamples
(
10
g
dry
weight)
of
sieved
(
2
mm)
sandy
loam
sediment
from
Northwood,
ND
(
62%
sand,
22%
silt,
16%
clay,
pH
8,
CEC
16.3
meq/
100g,
organic
carbon
1.6%)
were
weighed
into
culture
tubes
and
flooded
with
20
ml
of
lake
water
from
the
same
site
(
pH
8.7).
The
sediment
was
treated
with
a
sufficient
amount
of
methyl­
labeled
[
14C]
DDAC
(
didecyldimethylammonium
chloride,
radiochemical
purity
98.5
±
0.04%,
specific
activity
9.01
mCi/
mmol),
to
achieve
a
nominal
concentration
of
10
parts
per
million
(
ppm).
The
test
tubes
were
incubated
in
the
dark
at
25EC
for
365
days;
the
test
system
consisted
of
a
standard
tall
form
3000­
ml
resin­
pot
as
the
metabolism
vessel.
An
ethylene
glycol
trap,
a
sulfuric
acid
trap
and
two
potassium
hydroxide
traps
were
attached
for
the
collection
of
carbon
dioxide
(
CO2)
and
volatile
organic
compounds.
Sediment,
water
and
volatile
traps
were
sampled
for
analysis
at
0,
1,
3,
7,
14,
31,
61,
92,
123,
182,
273,
and
365
days
of
incubation.
Volatile
traps
were
also
sampled
at
151,
212,
243,
304
and
335
days
of
incubation.

At
each
sampling
interval,
sediment:
water
samples
were
centrifuged
and
the
aqueous
phase
decanted.
Before
analysis
by
thin
layer
chromatography
(
TLC),
the
6­,
9­,
and
12­
month
water
samples
were
concentrated
by
evaporating
aliquots
to
dryness
and
redissolving
in
methanol.
The
other
water
samples
were
not
concentrated
prior
to
analysis.
The
sediment
samples
were
extracted
with
30
ml
of
80:
20
(
v:
v)
dimethylfomamide
(
DMF):
acetic
acid
and
then
shaken
for
1
hour,
followed
by
centrifugation
for
10
minutes.
Quantification
and
identification
of
the
14C­
DDAC
residues
was
performed
using
TLC
and/
or
high
performance
liquid
chromatography
(
HLPC).

The
material
balance
averaged
105
±
2.8
%
of
the
applied
amount
for
the
year
long
study.
The
mean
total
recovery
of
the
radiolabelled
material
applied
was
1.5
±
0.9%
for
water
and
101.9
%
for
sediment
(
93.0
±
4.4%
for
extractable
residues
and
8.9
±
3.3%
non­
extractable
residues).
The
concentration
of
14C­
DDAC
in
water
decreased
from
2.20
%
at
day
0,
to
0.83%
of
the
applied
at
study
termination.
The
concentration
of
14C­
DDAC
in
the
sediment
increased
from
86.0%
at
day
0
to
87.8%
of
the
applied,
at
the
end
of
the
study
period.
At
test
termination,
101%
of
the
applied
radioactivity
was
partitioned
from
water
to
sediment.
Transformation
products
were
not
present
in
any
significant
amounts
in
the
water
or
sediment.

Extractable
[
14C]
residues
in
sediment
decreased
from
an
average
of
90.0
%
at
day
0,
to
89.9
%
of
the
applied
amount
at
the
end
of
incubation
period.
Non­
extractable
[
14C]
residues
in
sediment
increased
from
7.8%
at
day
0,
to
11.3%
of
the
applied
amount,
at
study
termination.
At
the
end
of
the
study,
4.5
%
of
the
recovered
radioactivity
was
present
as
volatiles.
The
volatiles
were
determined
to
be
14C­
carbon
dioxide
via
precipitation
with
barium
chloride.
12
of
17
As
determined
by
the
Agency,
the
half­
lives
of
14C­
DDAC
in
water,
sediment,
and
in
the
entire
system
were
180
days,
22,706
days
(
60.5
years),
and
8,366
days
(
22.9
years),
respectively.
The
Registrant
calculated
a
half­
life
of
8,365
days
for
14C­
DDAC
in
the
entire
system.
The
pathway
of
aerobic
biotransformation
of
14C­
DDAC
in
water­
sediment
system
was
not
described.

6.
Adsorption/
Desorption
(
OPP
Guideline
No.
163­
1,
MRID
No.
413853­
01)

This
adsorption/
desorption
study
was
reviewed
by
the
Agency
and
found
scientifically
valid.
This
study
partially
fulfills
the
adsorption/
desorption
data
requirements
for
DDAC
by
providing
information
on
the
mobility
(
batch
equilibrium)
of
unaged
14C­
DDAC
in
sodium
azide­
sterilized
sand,
sandy
loam,
silty
clay
loam,
and
silt
loam
soils.
Additional
data
are
required
on
the
mobility
of
aged
14C­
DDAC
residues
in
soil.

Based
on
the
results
of
preliminary
batch
equilibrium
studies,
an
equilibration
period
of
24
hours
and
a
soil:
solution
ratio
of
1:
200
(
w:
v)
were
chosen
for
this
study.
For
the
adsorption
phase
of
the
study,
aliquots
(
200
ml)
of
0.1
N
CaCl2
solution
containing
methyl­
labeled
[
14C]
DDAC
(
didecyldimethylammonium
chloride,
radiochemical
purity
97.5%,
specific
activity
9.01
mCi/
mmol),
at
nominal
concentrations
of
0.70,
3.50,
5.25,
and
7.0
µ
g/
ml,
were
added
to
sterile
Nalgene
screw­
cap
bottles
containing
subsamples
(
1
g)
of
sand,
sandy
loam,
silty
clay
loam,
or
silt
loam
soils.
The
soil
samples
had
been
air­
dried,
sieved
(
2
mm)
and
sterilized
by
addition
of
1%
sodium
azide
(
w:
w)
prior
to
the
experiment.
Triplicate
tubes
were
prepared
for
each
soil
type/
treatment
rate
combination.
After
the
adsorption
equilibration
period
of
24
hours
in
a
dark
environmentally
controlled
chamber
at
approximately
25
±
1EC,
the
soil:
solution
slurries
were
centrifuged
and
triplicate
aliquots
of
the
supernatant
were
analyzed
for
total
radioactivity
by
liquid
scintillation
counting
(
LSC).

For
the
desorption
phase
of
the
study,
pesticide­
free
0.01N
CaCl2
solution
(
equal
to
the
volume
removed
in
the
adsorption
phase)
was
added
to
the
soil
pellets
from
the
adsorption
phase
of
the
study.
The
soil:
solution
slurries
were
again
equilibrated
for
24
hours
at
approximately
25
±
1EC
in
the
dark.
Following
equilibration,
the
soil:
solution
slurries
were
centrifuged
and
triplicate
aliquots
of
the
supernatant
were
analyzed
for
total
radioactivity
by
LSC.

The
sandy
loam,
silty
clay,
and
silt
loam
samples
were
dried
and
analyzed
for
total
radioactivity
by
LSC
following
combustion.
The
sand
soil
samples
were
extracted
three
times
with
dimethylformamide:
acetic
acid
(
80:
20).
Following
extraction,
the
samples
were
centrifuged
and
aliquots
of
the
supernatant
were
analyzed
by
LSC.
Subsamples
of
the
extracted
soil
were
analyzed
by
LSC
following
combustion.

14C­
didecyl
dimethyl
ammonium
chloride
(
DDAC),
at
nominal
concentrations
of
0.70­
7.0
µ
g/
ml,
was
determined
to
be
immobile
in
sodium
azide­
sterilized
sand,
sandy
loam,
silty
clay
loam,
and
silt
loam
soil:
solution
slurries
(
1:
200)
that
were
equilibrated
in
darkness
at
25EC
±
1EC
for
24
hours.
Freundlich
Kads
values
were
1,095
for
sand,
8,179
for
the
sandy
loam,
32,791
for
the
silty
clay
loam,
and
30,851
for
the
silt
loam
soils.
Respective
Koc
values
were
437,805,
908,757,
1,599,564,
and
1469081.
13
of
17
Study
results
for
the
desorption
phase
indicate
that
16.26
to
39.33%
of
the
absorbed
radioactivity
was
desorbed
from
the
sand
soil,
2.20
to
12.60%
was
desorbed
from
the
sandy
loam
soil,
0.20
to
1.40%
was
desorbed
from
the
silty
clay
loam
soil,
and
0.20
to
1.66%
was
desorbed
from
the
silt
loam
soil.
Freundlich
Kdes
values
were
591
for
the
sand
soil,
2,074
for
the
sandy
loam
soil,
8,309
for
the
silty
clay
loam
soil,
and
7,714
for
the
silt
loam
soil.
Respective
Koc
values
were
236,473,
230,498,
405,328,
and
367334.

Material
balances
were
88.5
­
108.1%
for
the
sand
soil,
91.6
­
108.5%
for
the
sandy
loam
soil,
78.3
­
106.5%
for
the
silty
clay
loam
soil,
and
80.8
­
118.0%
for
the
silt
loam
soil.

7.
Field
dissipation
study
on
soil
(
OPP
Guideline
No.
164­
1)

A
field
dissipation
study
on
soil
is
required
for
DDAC.
No
data
have
been
submitted
to
the
Agency.

8.
Aquatic
field
dissipation
study
(
OPP
Guideline
No.
164­
2)

An
aquatic
field
dissipation
study
is
required
for
DDAC.
No
data
have
been
submitted
to
the
Agency.

9.
Long­
term
study
on
accumulation
on
soil
(
OPP
Guideline
No.
164­
5).

A
long­
term
study
on
accumulation
on
soil
is
required
for
DDAC
if
pesticide
residues
do
not
readily
dissipate
in
soil.
No
data
have
been
submitted
to
the
Agency.
.
10.
Bioaccumulation
in
Fish
(
OPP
Guideline
No.
165­
4,
MRID
No.
458341­
01)

This
bioaccumulation
study
was
reviewed
by
the
Agency
and
found
scientifically
valid.
It
satisfies
the
bioaccumulation
in
fish
data
requirements
for
DDAC.

In
this
study,
Bluegill
(
220)
were
continuously
exposed
to
a
nominal
concentration
of
59
µ
g/
L
of
DDAC
for
28
days
in
an
exposure
aquarium.
A
control
aquarium
was
also
used
which
had
the
same
conditions
as
the
treatment
aquarium.
Water
samples
were
collected
from
a
central
point
in
the
treatment
aquarium
on
days
0,
3,
4,
10,
11,
17,
and
24
of
exposure.
Five
fish
were
collected
for
tissue
analysis
from
the
treatment
aquarium
on
days
4,
10,
17,
24,
and
28
of
exposure.
Water
samples
and
fish
were
collected
from
the
control
aquarium
for
14C­
residues
on
days
0
and
28
of
exposure.

Following
a
28­
day
exposure
period,
40
of
the
fish
remaining
in
the
exposure
aquarium
were
transferred
to
an
aquarium
containing
untreated
dilution
water
for
an
18­
day
depuration
period.
Water
samples
were
collected
during
the
depuration
period
on
days
3,
7,
12,
and
18.
Five
fish
were
collected
on
days
3,
7,
14,
and
18
of
the
depuration
phase.
Water
samples
and
fish
were
collected
from
the
control
aquarium
on
day
18
of
depuration
for
14C­
residues.
14
of
17
The
aqueous
14C­
residues
measured
in
the
exposure
system
during
the
28
days
were
consistently
above
nominal,
at
a
mean
measured
concentration
of
93
µ
g/
L
(
±
32)
DDAC.
Concentrations
of
14C­
residues
present
in
the
depuration
aquarium
remained
at
<
11
µ
g
/
L
throughout
the
18
days.
The
levels
of
14C­
residues
in
the
edible,
non­
edible,
and
whole
tissue
of
bluegill
exposed
to
DDAC
reached
steady
state
by
day
10.
The
mean
steady
state
bioconcentration
factor
for
DDAC
in
the
edible,
nonedible
and
whole
body
tissue
of
the
bluegill
were
determined
by
the
authors
to
be
38X,
140X
and
81X,
respectively.
The
half­
life
of
the
14Cresidues
present
in
all
tissue
portions
of
the
bluegill
were
found
to
be
between
7
and
14
days.
The
elimination
of
14C­
residues
for
edible,
nonedible
and
whole
body
tissue
was
38%,
66%
and
56%,
respectively.
Of
the
accumulated
14C­
residues
in
the
edible
tissue
of
bluegill
exposed
28
days
to
DDAC,
65.5%
was
extractable
with
a
polar
solvent
(
methanol),
8.1%
was
extractable
with
a
non­
polar
solvent
(
hexane),
and
25.9%
was
not
extractable
with
either
solvent.
Analysis
of
skin
tissue
after
28
days
of
exposure
displayed
that
14C­
residue
levels
were
approximately
2
to
6
times
higher
than
those
observed
for
the
corresponding
edible
tissue.
Analytical
results
for
QA
samples
analyzed
concurrently
with
water
samples
during
the
exposure
and
depuration
period
resulted
in
a
mean
recovery
(
standard
deviation)
of
91
±
5.93
percent.
Analyses
of
the
QA
samples
analyzed
with
the
tissue
samples
during
exposure
and
depuration
resulted
in
a
mean
recovery
(
standard
deviation)
of
88.7
±
6.29
percent.

The
concentration
of
DDAC
in
the
treatment
aquarium
was
continuously
above
nominal
concentration
and
was
not
consistently
maintained
within
±
20
percent
of
the
mean
of
the
measured
values
(
93
µ
g
/
L).
The
temperature
recommended
for
testing
bluegill
is
20­
25
°
C.
In
this
study,
the
temperatures
ranged
between
17­
18
°
C.

The
study
authors
concluded
that
14C­
residues
reached
steady
state
by
day
10
of
exposure.
They
found
that
the
bioconcentration
factor
of
14C­
residues
in
edible
tissue
of
bluegill
was
much
lower
(
38X)
than
that
of
the
nonedible
tissues
(
140X)
and
also
found
that
DDAC
binds
significantly
to
the
non­
edible
segments
of
bluegill,
and
especially
to
the
skin
and
scales.
The
study
results
indicated
that
the
half­
life
of
DDAC
in
the
edible
tissue
of
the
bluegill
is
significantly
shorter
than
that
of
the
nonedible
segments.

11.
Photolysis
Rate
on
Surface
of
Soil
(
OPP
Guideline
No.
161­
3,
MRID
No.
424807­
01)

This
study
was
reviewed
by
the
Agency
and
was
found
to
be
scientifically
valid
and
acceptable.
The
study
meets
guidelines
for
the
fulfillment
of
data
requirements
for
DDAC
on
photodegradation
on
soil.

In
this
study,
aliquots
(
1
g
dry
weight)
of
sandy
loam
soil
were
placed
in
silanized
glass
vials
and
treated
with
[
14C]
DDAC
at
a
nominal
concentration
of
10
ppm.
Half
of
the
vials
were
placed
in
a
photolysis
chamber
where
they
were
exposed
to
a
xenon
arc
light
source
for
30
days
in
an
environmentally
controlled
chamber
at
25
±
1EC.
The
rest
of
the
vials
were
not
exposed
to
the
xenon
arc
light
source.
One
exposed
and
one
non­
exposed
test
sample
were
removed
from
the
photolysis
chamber
on
days
1,
3,
7,
14,
21,
and
30.
Each
vial
was
extracted
with
aliquots
of
80:
20
(
v:
v)
dimethylformamide:
acetic
acid.
Thin
layer
chromatography
15
of
17
(
TLC)/
autoradiography/
liquid
scintillation
counting
(
LSC)
were
used
to
measure
14C­
DDAC
and
potential
photolysis
products.

For
both
exposed
and
non­
exposed
test
systems,
the
mean
14C­
mass
balance
was
104%.
The
parent
compound
was
the
only
radioactive
component
obtained
in
the
test
samples
when
analyzed
by
TLC
and
HPLC.
In
the
exposed
system,
the
photolysis
rate
constant
and
half­
life
of
DDAC
were
reported
by
the
study
authors
as
5.26
x
10­
3
days­
1
and
132
days,
respectively.
The
photolysis
rate
constant
and
half­
life
of
DDAC
in
the
non­
exposed
system
were
determined
to
be
4.11
x
10­
3
days­
1
and
169
days,
respectively.

Soil
bound
residues
increased
from
9.48%
of
the
dose
at
day
0
to
25.5
and
20.9%
in
the
exposed
and
non­
exposed
test
systems,
respectively.
The
nature
of
these
bound
residues
was
investigated
by
HPLC
analysis
of
the
extracts
from
composites
of
reserve
day
30
soil
samples
from
both
systems.
The
analytical
results
indicated
the
presence
of
the
parent
compound
and
no
significant
degradation
products.

12.
Biodegradability
of
DDAC
(
No
MRID
Number)

This
report
is
an
assessment
of
the
biodegradability
of
DDAC
based
on
the
review
of
information
from
the
open
literature,
unpublished
sources
and
meeting
proceedings.
It
also
provides
a
summary
of
the
current
information
available
on
the
environmental
fate
of
DDAC.
The
report
was
submitted
by
the
Registrant
to
EPA,
but
has
not
been
reviewed
by
the
Agency.

Based
on
the
review
of
the
studies
in
the
report,
Lee
(
1992)
concluded
that:

"
Results
of
studies
published
in
the
open
literature,
literature
reviews,
conference
proceedings
and
information
obtained
from
unpublished
sources
indicate
that
ADBAC
and
DDAC
are
biodegradable
with
the
rate
and
extent
of
degradation
influenced
by
quat
concentration,
alkyl
chain
length,
the
presence
of
anionic
moieties,
and
the
type
of
microbes.
These
factors
and
the
design
of
the
test
system
are
important
in
interpreting
the
reliability
of
biodegradability
test
results.

After
release
of
ADBAC
and
DDAC
to
domestic
waste
streams
or
in
the
open
environment,
a
combination
of
physical
and
chemical
properties,
in
addition
to
biodegradability,
influence
their
fate
through
the
environmental
compartments
of
air,
water,
soil/
sediment
and
biota.
Important
properties
for
evaluating
the
environmental
fate
of
these
materials
include
solubility,
vapor
pressure,
surface
activity
and
adsorptive
properties."

13.
Aqueous
Availability
(
Leachability)
(
American
Wood­
Preservers'
Association
Standard
Method
E11­
97
"
Standard
Method
for
Determining
the
Leachability
of
Wood
Preservatives,
MRID
No.
455243­
05)

This
study
was
reviewed
by
the
Agency
based
on
the
standards
specified
by
the
American
Wood­
Preservers'
Association
Standard
Method
E11­
97
and
found
to
be
acceptable.
The
study
was
submitted
by
Lonza
Inc.
to
fulfill
the
requirements
for
registration
of
the
product,
16
of
17
Bardac
22C50,
EPA
File
Symbol
6836­
EGA.
Bardac
22C50
consists
of
two
active
ingredients:
didecylmethyl
ammonium
carbonate
(
DDACarb)
and
didecyl
ammonium
bicarbonate,
both
of
which
are
similar
in
structure
to
DDAC.

The
test
material
used
in
the
study
was
Bardac
22C,
which
contained
51.7%
of
the
active
ingredient
DDACarb.
The
purpose
of
this
study
was
to
determine
the
leach
rate
of
DDACarb
from
a
sample
of
treated
wood
in
deionized
water
using
high
performance
liquid
chromatography
(
HPLC).

Southern
pine
wood
blocks
(
19.0
±
0.2
mm)
were
vacuum
treated
with
0.85
percent,
1.7
percent,
and
3.4
percent
of
Bardac
22C
(
based
on
the
active
ingredient
DDACarb).
After
treatment,
the
blocks
were
subjected
to
a
post­
treatment
fixation
for
7
days
followed
by
conditioning
for
28
days
in
an
environment
producing
a
moisture
content
of
9
to
10
percent.
After
conditioning,
the
blocks
were
vacuum­
treated
with
deionized
water
and
placed
in
additional
deionized
water
for
14
days.

Leach
rates
of
DDACarb
from
wood
blocks
were
determined
by
removing
the
leachate
from
the
sampling
unit
at
intervals
of
6,
24,
and
48
hours,
and
4,
6,
8,
10,
12,
and
14
days
following
the
start
of
the
leaching
period.
The
leachate
was
extracted
with
aqueous
tetramethylammonium
chloride
(
TMAC)
and
methylene
chloride
and
analyzed
by
HPLC.
After
14
days
of
leaching,
the
wooden
blocks
were
extracted
with
acetonitrile
and
aqueous
TMAC
and
analyzed
by
HPLC.

The
corrected
amount
of
DDACarb
recovered
from
the
leachate
ranged
from
186.1
µ
g
to
764.7
µ
g
(
0.5X
retention
level),
from
218.9
µ
g
to
1152.9
µ
g
(
1X),
and
from
446.2
µ
g
to
2101.1
µ
g
(
2X).
The
total
recovery
from
the
leachate
over
the
14­
day
period
was
3464.7
µ
g,
4483.0
µ
g
and
7444.7
µ
g
for
the
0.5X,
1X
and
2X
retention
levels,
respectively.
For
all
three
retention
levels,
the
leachability
of
DDACarb
declined
continuously
over
the
14­
day
period
with
the
exception
of
the
leaching
rate
of
the
2X
retention
level,
which
began
lower
than
the
other
two
retention
levels
(
160.4
µ
g),
significantly
increased
at
Day
1
(
2101.1
µ
g),
and
decline
gradually
through
Day
14
(
496.8
µ
g).
The
total
amount
of
DDACarb
recovered
from
the
leachate
and
the
wood
blocks
combined
were
176,983.0
µ
g
(
101.8%),
286,606.6
µ
g
(
99.5%),
and
542,370.3
µ
g
(
104.9%)
for
the
0.5X,
1X
and
2X
retention
levels,
respectively.

American
Wood
Preservers'
Association
Standard,
Method
E11­
97:
"
Standard
Method
of
Determining
the
Leachability
of
Wood
Preservatives
was
generally
followed;
however,
an
issue
of
concern
was
that
the
study
did
not
report
running
spike
samples
along
with
the
test
samples
during
HPLC
analysis.
Rather,
the
samples
were
corrected
using
average
validated
extraction
recoveries
of
92.1
percent
from
three
different
fortification
levels
with
seven
replicates
per
level.
17
of
17
BIBLIOGRAPHY
MRID
Citation
411758­
01
Dykes,
J.
and
M.
Fennessy.
1989.
Hydrolysis
of
Didecyldimethylammonium
chloride
(
DDAC)
as
a
function
of
pH
at
25
°
C.
Final
Report
#
37004.
Unpublished
study
prepared
by
Analytical
Bio­
chemistry
Laboratories,
Inc.

411758­
02
Dykes,
J.
and
M.
Fennessy.
1989.
Determination
of
the
Photolysis
Rate
of
Didecyldimethylammonium
chloride
(
DDAC)
in
pH
7
Buffered
solution
at
25
°
C.
Final
Report
#
37005.
Unpublished
study
prepared
by
Analytical
Bio­
chemistry
Laboratories,
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413853­
01
Daly,
D.
1989.
Soil/
Sediment
Adsorption­
desorption
of
[
14C]
Didecyldimethylammonium
chloride
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14C­
DDAC).
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Unpublished
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422538­
01
Cranor,
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1991.
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422538­
02
Cranor,
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1991.
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Unpublished
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422538­
03
Cranor,
W.
1991.
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14C]
Didecyldimethylammonium
chloride
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14C­
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Unpublished
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prepared
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424807­
01
1992.
Schmidt,
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the
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prepared
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455243­
05
2001.
Bestari,
K.
Determination
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the
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22C
from
Treated
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Centre
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Toxicology,
University
of
Guelph,
Guelph,
Ontario
N1G
2W1,
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458341­
01
1990.
Fackler,
P.
H.,
E.
Dionne,
D.
A.
Hartley,
and
S.
P.
Shepherd.
Bioconcentration
and
Elimination
of
14C­
Residues
by
Bluegill
(
Lepomis
macrochirus)
Exposed
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Chloride
(
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Unpublished
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Contractor's
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Summary
