November
6,
1998
MEMORANDUM
SUBJECT:
RESPONSE
TO
COMMENTS
FROM
EXPOSAC
ON
EXPOSURE
ASSESSMENT
FOR
DICHLORVOS
(
DDVP)
FROM
FLEA
COLLARS
(
Barcode
D246127,
PC
Code
084001)

FROM:
David
Jaquith
Chemistry
and
Exposure
Branch
2
Health
Effects
Division
(
7509C)

TO:
Christina
Scheltema
Risk
Characterization
and
Analysis
Branch
Health
Effects
Division
(
7509C)

THRU:
Sue
Hummel,
Senior
Scientist
Chemical
Exposure
Branch
II
Health
Effects
Division
(
7509C)

1.0
INTRODUCTION
In
1987
EAB/
HED
conducted
a
number
of
exposure
assessments
in
support
of
the
Registration
Standard
for
DDVP
(
1).
The
potential
inhalation
exposures
resulting
to
residents
from
flea
collar
uses
were
included
in
that
assessment.
The
assessment
for
flea
collar
use
from
that
assessment
is
repeated
in
section
4
of
this
document.
EAB
later
conducted
an
exposure
assessment
for
the
animals
wearing
these
products
(
2).
The
exposure
estimate
for
the
human
exposure
scenario
was
presented
to
the
HED
Exposure
Science
Advisory
Council
(
EXPOSAC)
in
August
1998.
The
EXPOSAC
had
the
following
recommendations
(
3):

!
"
Include
characterization
of
data
and
assumptions
used
in
the
assessment
(
e.
g.,
conservative
nature
due
to
the
use
of
active
ingredient
values
from
cat
collars
to
represent
dog
collars
which
presumably
would
have
a
larger
amount
of
active
ingredient)."

!
"
Obtain
update
on
any
incidence
data
from
exposure
to
collars."
DDVP
­
Pet
Collars
Page
2
of
12
!
"
Include
assessment
of
child
sleeping
with
dog
for
eight
hours
as
bounding
estimate."

2.0
CONCLUSIONS
The
1987
exposure
assessments
addressed
persons
in
the
proximity
of
pets
treated
with
flea
collars
containing
DDVP
and
for
the
pets
themselves.
The
assessment
was
derived
from
a
study
conducted
by
a
previous
registrant
(
4).
The
study
contained
a
number
of
technical
flaws
but
remains
the
Agency's
only
source
of
chemical
specific
data
addressing
this
issue.
The
air
concentration
values
were
taken
from
the
original
PD4
from
the
Rebuttal
Presumption
Against
Registration
(
RPAR)
and
have
not
been
updated.
The
original
data
are
not
available.
The
inhalation
exposures
of
7
population
groups
to
DDVP
from
flea
collars.
The
following
groups
were
addressed:
adult
males;
adult
females;
children,
age
1­
2;
children,
age
3­
5;
children,
age
6­
8;
males,
age
9­
11;
and
females,
age
9­
11.
It
was
assumed
that
an
individual
spends
1
hour
in
close
contact
with
an
animal
wearing
a
flea
collar
and
8
hours
in
the
same
room.
An
estimate
of
exposure
assuming
that
an
individual
spends
8
hours
in
close
contact
while
sleeping
has
also
been
included
as
an
upper
bound.
The
latter
scenario
was
not
included
in
the
RED
package
but
are
included
here
for
comparison.
The
exposures
and
resulting
MOEs
for
these
population
groups
are
presented
in
Table
1.

The
exposure
estimates
do
not
include
a
dermal
component.
There
are
no
chemical
specific
data
currently
available
to
address
this
issue.
The
MOEs
presented
in
Table
1
for
total
exposure
(
excluding
close
contact
during
sleep)
range
from
14
to
38
and
yield
an
unacceptable
risk
even
without
the
inclusion
of
a
dermal
component.
This
risk
is
driven
largely
by
the
amount
of
time
in
close
contact
with
the
animal.
It
must
be
noted
that,
due
to
the
technical
difficulties
in
the
data
source
and
the
difficulty
of
extrapolating
these
limited
data
to
yield
an
exposure
assessment,
there
is
a
large
degree
of
uncertainty
associated
with
these
estimates.

The
respiratory
exposures
of
the
animals
wearing
these
products
were
also
estimated
in
an
earlier
document
to
be
53
:
g/
kg/
day
for
dogs
and
56
:
g/
kg/
day
for
cats
(
2).
The
corresponding
MOEs
would
be
0.94
for
dogs
and
0.89
for
cats.
There
are
no
data
with
which
to
estimate
the
dermal
component
of
the
total
exposure
or
with
which
to
update
these
estimates.
DDVP
­
Pet
Collars
Page
3
of
12
Table
1.
Estimated
Respiratory
Exposures
of
Individuals
in
Seven
Representative
Population
Groups
to
DDVP
from
the
Use
of
Flea
Collars.
Numbers
in
parentheses
are
Margins
of
Exposure.

Population
Group
Daily
Respiratory
Exposure
During
1
Hour
of
Close
Contact
in
mg/
kg/
day
(
MOE)
Daily
Respiratory
Exposure
During
8
Hours
of
Casual
Contact
in
mg/
kg/
day
(
MOE)
Total
Exposure;
Excluding
8
Hours
of
Close
Contact
with
Animal
Scenario
in
next
column.
(
MOE)
Exposure
During
8
Hours
of
Close
Contact
While
at
Rest
in
mg/
kg/
day
(
MOE)

Adult
Males
0.0014
(
36)
0.00012
(
417)
0.0015
(
33)
0.0093
(
5)

Adult
Females
0.0012
(
42)
0.00010
(
500)
0.0013
(
38)
0.0086
(
6)

Children,
1­
2
years
old
0.0034
(
15)
0.00029
(
172)
0.0037
(
14)
Not
Available
Children,
3­
5
years
old
0.0031
(
16)
0.00026
(
192)
0.0033
(
15)
0.026
(
2)

Children,
6­
8
years
old
0.0025
(
20)
0.00022
(
227)
0.0027
(
19)
0.022
(
2)

Males,
9­
11
years
old
0.0024
(
21)
0.00021
(
238)
0.0026
(
19)
0.015
(
3)

Females,
9­
11
years
old
0.0022
(
23)
0.00019
(
263)
0.0023
(
22)
0.015
(
3)
DDVP
­
Pet
Collars
Page
4
of
12
3.0
LABEL
INFORMATION
The
relevant
features
of
the
current
labels
for
flea
collar
products
are
presented
in
Table
2.
In
general,
all
of
the
products
have
the
similar
warning
statements.
They
state
that
the
collar
should
be
removed
when
the
pet
is
bathed
and
remain
off
until
the
animal
is
dry.
They
are
not
to
be
used
on
sick,
convalescing,
pregnant
or
nursing
pets.
Other
pesticides
are
not
to
be
used
on
the
pet
while
the
collar
is
being
worn.
Some
labels
for
cat
products
state
that
the
collars
are
not
to
be
used
on
Persians.
Most
labels
specify
that
the
products
are
effective
for
3
months.
The
range
of
DDVP
concentrations
is
4.37
to
4.8
percent
for
cats
and
7
to
9
percent
DDVP
for
the
dog
collars.

Table
2.
Summary
of
Contents
of
Labels
for
Flea
Collar
Products
Containing
DDVP.

EPA
No.
Wt.
of
Wt.
of
Pct
DDVP
Total
DDVP
Duration
of
Type
of
Collar
Collar
(
g)
Action
Pet
(
oz)
(
g)

5481­
343
0.6
17
8.37
1.4
3
months
Dog
778­
24
0.4
11
4.37
0.5
3
months
Cat
778­
83
1.1
31
7
2.2
3
months
Large
Dog
778­
87
0.9
24
9
2.2
5
months
Dog
4691­
127
0.4
11
4.8
3
months
Cat
4691­
126
0.8
23
9.6
2.2
8
weeks
Dog
5481­
342
0.4
11.3
4.37
0.5
3
months
Cat
5481­
345
0.4
11.3
4.37
0.5
3
months
Cat
5481­
347
0.4
11.3
4.37
0.5
3
months
Cat
5481­
343
0.6
17
8.37
1.4
3
months
Dog
5481­
346
0.6
17
8.37
1.4
3
months
Dog
5481­
346
0.6
17
8.37
1.4
3
months
Dog
42835­
03
0.46
13
4.37
0.6
3
months
Cat
42836­
01
0.78
22
8.37
1.8
3
months
Dog
DDVP
­
Pet
Collars
Page
5
of
12
4.0
Assessment
from
EAB
Assessment
of
August
4,
1987
(
Any
current
comments
are
in
BOLDFACE)

EXPOSURE
OF
RESIDENTS
FROM
FLEA
COLLAR
USE
A.
Calculation
of
the
PD4
of
the
RPAR
­
NOT
UPDATED,
DATA
FROM
THE
ORIGINAL
STUDY
NOT
AVAILABLE
1)
Assumptions
a)
Casual
exposure
to
a
pet
wearing
a
flea
collar
occurs
for
8
hours
per
day.

b)
Exposure
near
the
breathing
zone
of
the
pet
occurs
for
1
hour
per
day.

c)
There
is
a
room
dilution
factor
of
10
for
DDVP
vapors.

d)
An
average
resident
weighs
70
kg
and
has
a
respiratory
volume
of
1.2
m3
per
hour
(
6).

2)
Study
by
Van
Kampen
(
1977)
(
4)

Concentration
of
DDVP
in
room
from
pet
with
one
collar:

a)
Room
(
casual
exposure)
range:
0.00013
­
0.0031
mg/
m3
Mean:
0.0016
mg/
m3
b)
Breathing
zone
range:
0.003
­
0.29
mg/
m3
Mean:
0.15
mg/
m3
Potential
Daily
Exposure
Casual
Exposure
=
0.0016
mg/
m3
x
1.2
m3/
hr
x
8
hr/
day
x
0.1
=
0.0015
mg/
day
Breathing
zone
=
0.15
mg/
m3
x
1.2
m3/
hr
x
1
hr/
day
x
0.1
=
0.018
mg/
day
Total
Daily
Exp.
=
(
0.0015
mg/
day
+
0.018
mg/
day)
x
1/
70
kg
(
mg/
kg/
day)
=
0.0003
mg/
kg/
day
DDVP
­
Pet
Collars
Page
6
of
12
B.
Reassessment
from
Memorandum
of
August
4,
1987
The
reassessment
uses
the
same
concentrations
and
the
same
exposure
times
as
the
PD4.

1)
Assumptions
a)
A
resident
weighs
70
kg
and
has
respiratory
volumes
of
0.44
and
1.7
m3/
hr
while
at
rest
and
while
performing
light
tasks,
respectively.

b)
A
resident
spends
1/
3
of
his
time
performing
light
tasks
and
the
remaining
2/
3
at
rest.
The
average
respiratory
volume
is:

Average
Respiratory
Volume
=
(
1/
3
x
1.7
m3/
hr)
+
(
2/
3
x
0.44
m3)

=
0.86
m3
c)
A
resident
is
exposed
to
concentration
of
0.15
mg
per
m3
(
breathing
zone)
for
1
hour
per
day
and
a
concentration
of
0.0016
mg
per
m3
for
8
hours
per
day
(
casual
exposure).

2)
Calculation
of
Exposures
Daily
Exposure
=
(
0.15
mg/
m3
x
1
hr
+
0.0016
mg/
m3
x
8
hr)
x
0.86
m3/
hr
x
1/
70
kg
x
0.1
=
0.00021
mg/
kg/
day
Annual
Exposure
=
0.00021
mg/
kg/
day
x
365
days/
year
=
0.077
mg/
kg/
yr
C.
Conclusions
EAB
has
no
additional
information
with
which
to
estimate
exposure
of
residents
of
homes
in
which
flea
collars
are
employed.
The
reassessment
is
essentially
in
agreement
with
the
PD4
assessment
with
minor
changes
in
resident
respiratory
volume.

5.0
Clarifications/
Changes
Requested
by
EXPOSAC
5.1
Include
characterization
of
data
and
assumptions
used
in
the
assessment
(
e.
g.,
conservative
nature
due
to
the
use
of
active
ingredient
values
from
cat
collars
to
represent
dog
collars
which
presumably
would
have
a
larger
amount
of
active
ingredient).

There
are
minimal
data
addressing
the
exposures
of
individuals
or
their
pets
to
DDVP
from
the
use
of
flea
collars.
No
new
chemical
specific
data
have
been
received
since
the
original
assessment
conducted
in
1987.
The
assessment,
originally
presented
in
the
PD4
for
the
RPAR
for
this
compound,
was
derived
using
air
monitoring
data
from
a
weak
study
in
which
cats
were
fitted
DDVP
­
Pet
Collars
Page
7
of
12
with
flea
collars.
An
undocumented
dilution
factor
of
10
was
used
for
DDVP
vapors
in
the
PD4
for
the
RPAR.
The
body
weight
and
respiratory
volume
were
changed
slightly
in
the
1987
assessment
to
account
for
the
Agency
policies
then
in
use.
Fundamentally,
the
assessment
did
not
change
and
remains
weak.
The
potential
exposures
of
children
were
not
considered
in
the
assessment
conducted
in
1987.
There
are
no
data
with
which
to
estimate
any
dermal
component
to
the
total
DDVP
exposure.

The
EXPOSAC
expressed
concern
that
the
amount
of
DDVP
in
dog
collars
is
greater
than
that
in
products
intended
for
cats.
It
is
not
known
whether
the
greater
amount
of
DDVP
in
the
collar
would
have
any
appreciable
effect
on
the
air
concentrations
since
the
DDVP
in
the
collar
must
diffuse
through
the
resin
in
order
to
be
released
into
the
air.

5.2
Obtain
update
on
any
incidence
data
from
exposure
to
collars.

The
reviewer
defers
to
HED's
experts
in
the
analysis
of
incidents
to
address
this
issue.
The
analysis
of
incidents
will
be
part
of
the
RED
for
this
compound.

5.3
Include
assessment
of
child
sleeping
with
dog
for
8
hours
as
bounding
estimate.

As
mentioned
in
Section
5.1,
the
exposures
of
children
were
not
considered
in
the
assessment
conducted
in
1987.
It
was
assumed
that
an
adult
spent
1
hour
in
close
contact
(
breathing
zone
value)
with
the
animal
and
8
hours
in
the
room
(
casual
exposure).
The
EXPOSAC
has
recommended
that
a
scenario
considering
an
8
hour
exposure
to
a
child
be
included
as
a
bounding
estimate.
In
response
to
this
request
the
exposure
assessment
was
expanded,
not
only
to
include
this
scenario,
but
also
to
address
the
exposures
of
seven
population
groups.
The
daily
respiratory
volumes
of
individuals
and
body
weights
for
children
were
obtained
from
the
Exposure
Factors
Handbook
(
7).
The
daily
respiratory
rates,
calculated
by
dividing
the
daily
values
by
24
hours,
were
used
since
it
is
not
known
what
levels
of
activity
might
occur
during
exposure.

The
previous
assessment
assumed
that
an
individual
spent
1
hour
per
day
in
close
proximity
to
an
animal
wearing
a
flea
collar
(
breathing
zone
concentration,
BZ
=
0.15
mg/
m
³
)
and
8
hours
in
the
general
area
(
room
concentration,
RC
=
0.0016
mg/
m
³
)
.
These
assumptions
were
used
for
this
assessment
also.
An
estimate
of
the
exposures
of
individuals
exposed
to
the
breathing
zone
concentration
for
8
hours
has
also
been
included.
For
the
8
hour
close
contact
scenario
it
was
assumed
that
the
individual
was
at
rest
during
this
time.
The
respiratory
NOAEL
of
0.05
mg/
kg/
day
(
5)
was
used
for
calculation
of
MOEs.
The
daily
volumes,
average
hourly
volumes,
average
hourly
volumes
while
at
rest,
and
body
weights
of
the
seven
population
groups
are
presented
in
Table
3.
The
equations
used
for
calculation
of
exposures
were:

Typical
Exposure
(
1
hr
close,
8
hrs
casual):

Exposure
=
[(
1
hr
x
BZ
Conc
(
mg/
m3)
+
(
8
hrs
x
Rm
Conc
(
mg/
m3)]
x
Resp.
Rate,
(
m3/
hr)
(
mg/
kg/
day)
BW
(
kg)
DDVP
­
Pet
Collars
Page
8
of
12
where:
BZ
=
breathing
zone,
close
to
the
animal
Rm
=
room
zone,
casual
exposure
BW
=
body
weight
8
Hours
Close
Contact
while
at
rest:

Exposure
(
mg/
kg/
day)
=
[(
8
hrs
x
BZ
Conc
(
mg/
m3)
BW
(
kg)

The
resulting
exposures
are
presented
in
Table
4
and
the
MOEs
are
presented
in
Table
5.
DDVP
­
Pet
Collars
Page
9
of
12
Table
3.
Daily
Respiratory
Rates,
Average
Hourly
Respiratory
Rates,
and
Body
Weights
for
5
Representative
Population
Classes.

Population
Class
Daily
Respiratory
Rate
(
m
³
/
day)
1
Average
Hourly
Respiratory
Rate
(
m
³
/
hr)
Average
Hourly
Respiratory
Rate
(
m
³
/
hr)
While
at
Rest2
Body
Weight
(
kg)

Adult
Males
15.2
0.63
0.54
70
Adult
Females
11.3
0.47
0.43
60
Children,
1­
2
years
old
6.8
0.28
Not
Available
12.34
Children,
3­
5
years
old
8.3
0.35
0.37
175
Children,
6­
8
years
old
10
0.42
0.453
256
Males,
9­
11
years
old
14
0.58
0.453
367
Females,
9­
11
years
old
13
0.54
0.453
378
1
From
Exposure
Factors
Handbook,
Table
5­
23.
2
From
Exposure
Factors
Handbook,
Table
5­
6.
3
From
Exposure
Factors
Handbook,
Table
5­
6,
resting
value
for
children,
age
6­
12.9
years.
4
From
Exposure
Factors
Handbook,
Table
7­
3,
average
of
means
for
2
year
old
children.
5
From
Exposure
Factors
Handbook,
Table
7­
3,
average
of
means
for
3
year,
4
year,
and
5
year
old
children.
6
From
Exposure
Factors
Handbook,
Table
7­
3,
average
of
means
for
6
year,
7
year,
and
8
year
old
children.
7
From
Exposure
Factors
Handbook,
Table
7­
3,
average
of
means
for
9
year,
10
year,
and
11
year
old
females.
8
From
Exposure
Factors
Handbook,
Table
7­
3,
average
of
means
for
9
year,
10
year,
and
11
year
old
females.
DDVP
­
Pet
Collars
Page
10
of
12
Table
4.
Daily
Respiratory
Exposures
of
Seven
5
Representative
Population
Groups
to
DDVP
from
Flea
Collars.

Population
Group
Daily
Respiratory
Exposure
During
1
Hour
of
Close
Contact
(
mg/
kg/
day)
Daily
Respiratory
Exposure
During
8
Hours
of
Casual
Contact
(
mg/
kg/
day)
Total
Exposure
(
Excluding
8
Hours
of
Close
Contact
with
Animal
Scenario
in
next
column)
Exposure
During
8
Hours
of
Close
Contact
While
at
Rest
(
mg/
kg/
day)

Adult
Males
0.0014
0.00012
0.0015
0.0093
Adult
Females
0.0012
0.00010
0.0013
0.0086
Children,
1­
2
years
old
0.0034
0.00029
0.0037
Not
Available
Children,
3­
5
years
old
0.0031
0.00026
0.0033
0.026
Children,
6­
8
years
old
0.0025
0.00022
0.0027
0.022
Males,
9­
11
years
old
0.0024
0.00021
0.0026
0.015
Females,
9­
11
years
old
0.0022
0.00019
0.0023
0.015
DDVP
­
Pet
Collars
Page
11
of
12
Table
5.
Margins
of
Exposure
(
MOEs)
For
Residents
of
Homes
Resulting
from
the
Use
of
Flea
Collars
Containing
DDVP.

Population
Group
MOE
Resulting
from
1
Hour
of
Close
Contact
MOE
Resulting
From
8
Hours
of
Casual
Contact
MOE
from
Both
Sources
MOE
8
Hours
of
Close
Contact
While
at
Rest
Adult
Males
36
417
33
5
Adult
Females
42
500
38
6
Children,
1­
2
years
old
15
172
14
Not
Available
Children,
3­
5
years
old
16
192
15
2
Children,
6­
8
years
old
20
227
19
2
Males,
9­
11
years
old
21
238
19
3
Females,
9­
11
years
old
23
263
22
3
DDVP
­
Pet
Collars
Page
12
of
12
REFERENCES
1)
Memorandum
from
D.
Jaquith
(
EAB)
to
C.
Monroe
(
SIS)
titled
"
Exposure
Assessment
for
DDVP",
dated
August
4,
1987.

2)
Memorandum
from
D.
Jaquith
(
EAB)
to
C.
Monroe
(
SIS)
titled
"
Exposure
of
Cats
and
Dogs
to
DDVP
from
Flea
Collar
Use",
dated
August
11,
1987.

3)
Memorandum
from
J.
Arthur
(
EXPOSAC
Chair)
to
D.
Jaquith
(
CEB2)
titled
"
Review
of
DDVP
Exposure
Assessment
for
Scenarios:
Total
Release
Fogger;
Turf;
Aerosol
Crack/
Crevice
Treatment,
and
Pet
Collars",
dated
August
31,
1998.

4)
Van
Kampen,
K.
R.,
D.
R.
Brooks,
and
S.
D.
Allen
(
1977)
Influence
of
High
Temperature
and
Low
Humidity
On
Cats
Wearing
Single
and
Multiple
Dichlorvos
Flea
Collar.
Shell
Chemical
Company.

5)
Federal
Register
Notice,
September
28,
1995,
Dichlorvos;
Notice
of
Preliminary
Determination
to
Cancel
Certain
Registrations
and
Draft
Notice
of
Intent
to
Cancel;
Notice.
Page
50352.

6)
EPA
(
1987),
Pesticide
Assessment
Guidelines
­
Subdivision
U
Applicator
Exposure.
PB87­
133286.

7)
EPA,
Exposure
Factors
Handbook,
Volume
I,
EPA/
600/
P­
95/
002Fa,
August
1997.

cc:
Dichlorvos
file/
084001
Correspondence
file
S.
Hummel
(
CEB2/
7509C)
D.
Utterback
(
7508W)
