Imazapyr
Dietary
Exposure
Assessment
DP
Barcode:
D288806
PC
Code:
128821
Page:
1
of
7
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
MEMORANDUM
DATE:
26­
MAR­
2003
SUBJECT:
Imazapyr.
Chronic
Dietary
Exposure
Assessment
for
the
Section
3
Registration
Action
on
Grasses
and
Aquatic
Sites.

PC
Code:
128821
DP
Barcode:
D288806
REVIEWER:
William
H.
Donovan,
Ph.
D.,
Chemist
Reregistration
Branch
3
(
RRB3)/
Health
Effects
Division
(
HED)
(
7509C)

THROUGH:
Thurston
Morton,
Chemist
Sheila
Piper,
Chemist
Dietary
Exposure
Science
Advisory
Council
(
DESAC)
HED
(
7509C)

and
G.
Jeffrey
Herndon,
Branch
Senior
Scientist
Registration
Action
Branch
1
(
RAB1)/
HED
(
7509C)

TO:
Dana
Vogel,
Risk
Assessor
RAB1/
HED
(
7509C)

Executive
Summary
The
purpose
of
this
memorandum
is
to
report
the
results
of
a
dietary
exposure
analysis
for
imazapyr.
In
this
analysis
the
chronic
dietary
exposure
and
risk
estimates
resulting
from
food
intake
were
determined
for
the
general
U.
S.
population
and
various
population
subgroups.

A
chronic
dietary
exposure
analysis
was
performed
in
order
to
determine
the
exposure
and
risk
estimates
which
result
from
the
addition
of
fish,
shellfish,
and
livestock
commodities
to
the
commodity
residue
list
for
imazapyr.
The
proposed
tolerances
are
associated
with
Section
3
requests.
Imazapyr
Dietary
Exposure
Assessment
DP
Barcode:
D288806
PC
Code:
128821
Page:
2
of
7
The
chronic
dietary
analysis
for
imazapyr
shows
that
the
exposure
for
all
population
subgroups
is
below
HED's
level
of
concern.
All
population
subgroups
are
predicted
to
have
exposures
<
0.1%
of
the
cPAD.

I.
Introduction
Dietary
risk
assessment
incorporates
both
exposure
and
toxicity
of
a
given
pesticide.
For
acute
and
chronic
assessments,
the
risk
is
expressed
as
a
percentage
of
a
maximum
acceptable
dose.
This
is
the
population
adjusted
dose
(
PAD),
which
HED
has
concluded
will
result
in
no
unreasonable
adverse
health
effects.
The
PAD
is
the
Reference
Dose
(
RfD)
divided
by
the
special
FQPA
Safety
Factor.
Dietary
risk
is
expressed
as
a
percentage
of
the
PAD.
For
acute
and
noncancer
chronic
exposures,
HED
is
concerned
when
estimated
dietary
risk
exceeds
100%
of
the
PAD.
References
which
discuss
the
acute
and
chronic
risk
assessments
in
more
detail
are
available
on
the
EPA/
pesticides
web
site:
"
Available
Information
on
Assessing
Exposure
from
Pesticides,
A
User's
Guide",
6/
21/
2000,
web
link:
http://
www.
epa.
gov/
fedrgstr/
EPA­
PEST/
2000/
July/
Day­
12/
6061.
pdf
;
or
see
SOP
99.6
(
8/
20/
99).

II.
Residue
Information
New
Uses
For
the
proposed
new
uses,
HED
recommended
tolerance
levels
were
employed
in
the
DEEMFCID
analysis
together
with
100%
CT
assumptions
and
DEEM
default
processing
factors.
These
recommended
levels
were
taken
from
the
appropriate
chemistry
review
(
D275561,
W.
Donovan,
20­
MAR­
2003)]
and
are
summarized
as
follows:

Grass,
forage
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
100
ppm
Grass,
hay
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
30
ppm
Fish
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
1.0
ppm
Shellfish
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
0.10
ppm
Fat
of
cattle,
sheep,
goats,
and
horses
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
0.05
ppm
Kidney
of
cattle,
sheep,
goats,
and
horses
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
0.20
ppm
Meat
byproducts
(
except
kidney)
of
cattle,
sheep,
goats,
and
horses
.
.
.
.
.
.
.
.
.
.
.
.
.
.
0.05
ppm
Meat
of
cattle,
sheep,
goats,
and
horses
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
0.05
ppm
Milk
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
0.01
ppm
Note
that
the
above
listed
tolerance
levels
are
expressed
in
terms
of
imazapyr
per
se,
consistent
with
the
HED
Metabolism
Assessment
Review
Committee
(
MARC)
decision
that
the
residue
of
concern
for
the
tolerance
expression
and
for
risk
assessment
purposes
is
parent
only
in
plants,
livestock,
fish,
and
water
(
TXR#
0051641,
W.
Donovan
and
E.
Rinde,
13­
MAR­
2003).
Imazapyr
Dietary
Exposure
Assessment
DP
Barcode:
D288806
PC
Code:
128821
Page:
3
of
7
Established
Uses
A
listing
of
established
imazapyr
tolerances
(
for
residues
of
imazapyr
per
se)
is
given
in
40
CFR
§
180.500.
This
listing
consists
of
field
corn
raw
agricultural
commodities
(
RACs),
all
at
0.05
ppm.

III.
DEEM­
FCID
 
Program
and
Consumption
Information
An
imazapyr
chronic
dietary
exposure
assessment
was
conducted
using
the
Dietary
Exposure
Evaluation
Model
software
with
the
Food
Commodity
Intake
Database
(
DEEM­
FCID
 
,
Version
1.3),
which
incorporates
consumption
data
from
USDA's
Continuing
Surveys
of
Food
Intakes
by
Individuals
(
CSFII),
1994­
1996
and
1998.
The
1994­
1996
and
1998
data
are
based
on
the
reported
consumption
of
more
than
20,000
individuals
over
two
non­
consecutive
survey
days.
Foods
"
as
consumed"
(
e.
g.,
apple
pie)
are
linked
to
EPA­
defined
food
commodities
(
e.
g.
apples,
peeled
fruit
­
cooked;
fresh
or
N/
S;
baked;
or
wheat
flour
­
cooked;
fresh
or
N/
S,
baked)
using
publicly
available
recipe
translation
files
developed
jointly
by
USDA/
ARS
and
EPA.
Consumption
data
are
averaged
for
the
entire
U.
S.
population
and
within
population
subgroups
for
chronic
exposure
assessment,
but
are
retained
as
individual
consumption
events
for
acute
exposure
assessment.

For
chronic
exposure
and
risk
assessment,
an
estimate
of
the
residue
level
in
each
food
or
foodform
(
e.
g.,
orange
or
orange
juice)
on
the
food
commodity
residue
list
is
multiplied
by
the
average
daily
consumption
estimate
for
that
food/
food
form.
The
resulting
residue
consumption
estimate
for
each
food/
food
form
is
summed
with
the
residue
consumption
estimates
for
all
other
food/
food
forms
on
the
commodity
residue
list
to
arrive
at
the
total
average
estimated
exposure.
Exposure
is
expressed
in
mg/
kg
body
weight/
day
and
as
a
percent
of
the
cPAD.
This
procedure
is
performed
for
each
population
subgroup.

IV.
Toxicological
Information
The
Hazard
Identification
Assessment
Review
Committee
(
HIARC)
discussed
the
toxicity
of
imazapyr
in
a
meeting
held
on
06­
FEB­
2003
(
TXR#
0051689,
E.
Rinde,
25­
MAR­
2003).
The
relevant
dietary
exposure
toxicological
doses
and
endpoints
selected
by
the
HIARC
are
summarized
in
Table
1.
Based
on
the
HIARC
conclusions
and
the
imazapyr
risk
assessment
team's
evaluation
of
the
hazard
and
exposure
data,
the
team
recommended
that
the
Special
FQPA
Safety
Factor
be
reduced
to
1x.
Imazapyr
Dietary
Exposure
Assessment
DP
Barcode:
D288806
PC
Code:
128821
Page:
4
of
7
Table
1.
Summary
of
Toxicological
Doses
and
Endpoints
for
Imazapyr
for
Use
in
Dietary
Exposure
Assessment
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
FQPA
SF*
and
Endpoint
for
Risk
Assessment
Study
and
Toxicological
Effects
Acute
Dietary
females
13­
50
years
old
and
general
population
none
none
An
appropriate
endpoint
attributable
to
a
single
oral
dose
was
not
available
in
the
data
base.

Chronic
Dietary
all
populations
NOAEL=
250
mg/
kg/
day
UF
=
100
Chronic
RfD
=
2.5
mg/
kg/
day
FQPA
SF
=
1X
cPAD
=
cRfD
FQPA
SF
=
2.5
mg/
kg/
day
1­
year
dog
(
feeding)
study
No
LOAEL
found
as
250
mg/
kg/
day
was
highest
dose
tested
(
HDT).
Endpoint
of
concern
may
be
translated
from
that
of
imazapic
where
skeletal
muscle
effects
were
seen
in
dogs.

Cancer
Cancer
classification
"
Group
E"
in
26­
APR­
1995
CPRC
meeting
N/
A
N/
A
V.
Results/
Discussion
As
stated
above,
for
chronic
assessments,
HED
is
concerned
when
dietary
risk
exceeds
100%
of
the
cPAD.
The
DEEM­
FCID
 
analysis
estimates
the
dietary
exposure
of
the
U.
S.
population
and
26
population
subgroups.
The
results
reported
in
Table
2
are
for
the
general
U.
S.
Population,
all
infants
(<
1
year
old),
children
1­
2,
children
3­
5,
children
6­
12,
youth
13­
19,
females
13­
49,
males
20­
49,
and
adults
50+
years.

Results
of
Chronic
Dietary
Exposure
Analysis
Table
2.
Results
of
Chronic
Dietary
Exposure
Analysis
for
Imazapyr.

Population
Subgroup
cPAD
(
mg/
kg/
day)
Exposure
(
mg/
kg/
day)
%
cPAD
General
U.
S.
Population
2.5
0.000340
<
0.1
All
Infants
(<
1
year
old)
2.5
0.000273
<
0.1
Children
1­
2
years
old
2.5
0.000828
<
0.1
Children
3­
5
years
old
2.5
0.000730
<
0.1
Children
6­
12
years
old
2.5
0.000499
<
0.1
Youth
13­
19
years
old
2.5
0.000309
<
0.1
Imazapyr
Dietary
Exposure
Assessment
DP
Barcode:
D288806
PC
Code:
128821
Page:
5
of
7
Table
2.
Results
of
Chronic
Dietary
Exposure
Analysis
for
Imazapyr.

Population
Subgroup
cPAD
(
mg/
kg/
day)
Exposure
(
mg/
kg/
day)
%
cPAD
Adults
20­
49
years
old
2.5
0.000267
<
0.1
Females
13­
49
years
old
2.5
0.000257
<
0.1
Adults
50+
years
old
2.5
0.000287
<
0.1
VI.
Discussion
of
Uncertainties
Adequate
data
are
available
for
the
determination
of
tolerance
levels,
as
discussed
in
the
applicable
residue
chemistry
memos.
For
fish
and
shellfish,
the
tolerance
levels
are
based
on
residue
levels
measured
in
magnitude
of
the
residue
studies,
as
opposed
to
being
based
on
the
method
LOQ.
For
field
corn,
and
all
livestock
commodities
except
kidney,
the
tolerance
levels
are
set
at
the
method
LOQ.
For
kidney,
use
of
maximum
grass
residue
levels
in
conjunction
with
the
results
of
a
bovine
feeding
study,
allowed
projection
of
a
maximum
imazapyr
residue
level
of
0.20
ppm
(
the
recommended
tolerance
level).

The
present
dietary
exposure
analysis
made
use
of
tolerance­
level
residues,
100%
crop
treated
assumptions,
and
DEEM
default
processing
factors.
All
processing
factors
in
the
current
analysis
were
1.0
except
for
the
"
beef,
meat,
dried"
factor
where
a
value
of
1.92
was
used.
Thus,
the
exposure
estimates
provided
here
overestimate
the
actual
risk.
With
the
current
low­
level
of
risk
from
imazapyr,
refinement
was
determined
to
be
unnecessary.

VII.
Conclusions
The
Tier
1
chronic
dietary
risk
assessment
for
imazapyr
shows
that
exposures
for
all
population
subgroups
are
below
HED's
level
of
concern.
Total
food
exposure
for
all
population
subgroups
was
determined
to
occupy
<
0.1%
cPAD.

VIII.
List
of
Attachments
Attachment
1:
Imazapyr
Tier
1
residue
file
for
chronic
DEEM
 
analysis.
Attachment
2:
Imazapyr
Chronic
DEEM
 
analysis.

cc
(
with
Attachments):
W.
Donovan,
W.
Cutchin
RDI:
G.
Herndon
(
26­
MAR­
2003)
W.
H.
Donovan:
821B:
CM#
2:(
703)
305­
7330:
7509C:
RRB3
Imazapyr
Dietary
Exposure
Assessment
DP
Barcode:
D288806
PC
Code:
128821
Page:
6
of
7
ATTACHMENT
1.
RESULTS
OF
CHRONIC
DEEM
ANALYSIS.

U.
S.
Environmental
Protection
Agency
Ver.
1.30
DEEM­
FCID
Chronic
analysis
for
IMAZAPYR
(
1994­
98
data)
Residue
file
name:
C:\
DEEMFCID\
128821.
r98
Adjustment
factor
#
2
NOT
used.
Analysis
Date
03­
20­
2003/
14:
16:
24
Residue
file
dated:
03­
20­
2003/
14:
11:
01/
8
Reference
dose
(
RfD,
Chronic)
=
2.5
mg/
kg
bw/
day
COMMENT
1:
PP#
0F6166
(
grass
&
aquatic
uses)
===============================================================================
Total
exposure
by
population
subgroup
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­

Total
Exposure
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
Population
mg/
kg
Percent
of
Subgroup
body
wt/
day
Rfd
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
­­­­­­­­­­­­­
­­­­­­­­­­­­­­­
U.
S.
Population
(
total)
0.000340
0.0%

U.
S.
Population
(
spring
season)
0.000360
0.0%
U.
S.
Population
(
summer
season)
0.000344
0.0%
U.
S.
Population
(
autumn
season)
0.000334
0.0%
U.
S.
Population
(
winter
season)
0.000320
0.0%

Northeast
region
0.000366
0.0%
Midwest
region
0.000321
0.0%
Southern
region
0.000324
0.0%
Western
region
0.000360
0.0%

Hispanics
0.000349
0.0%
Non­
hispanic
whites
0.000312
0.0%
Non­
hispanic
blacks
0.000409
0.0%
Non­
hisp/
non­
white/
non­
black
0.000566
0.0%

All
infants
(<
1
year)
0.000273
0.0%
Nursing
infants
0.000075
0.0%
Non­
nursing
infants
0.000348
0.0%
Children
1­
6
yrs
0.000739
0.0%
Children
7­
12
yrs
0.000483
0.0%

Females
13­
19
(
not
preg
or
nursing)
0.000276
0.0%
Females
20+
(
not
preg
or
nursing)
0.000266
0.0%
Females
13­
50
yrs
0.000273
0.0%
Females
13+
(
preg/
not
nursing)
0.000244
0.0%
Females
13+
(
nursing)
0.000294
0.0%

Males
13­
19
yrs
0.000343
0.0%
Males
20+
yrs
0.000283
0.0%
Seniors
55+
0.000287
0.0%

Children
1­
2
yrs
0.000828
0.0%
Children
3­
5
yrs
0.000730
0.0%
Children
6­
12
yrs
0.000499
0.0%
Youth
13­
19
yrs
0.000309
0.0%
Adults
20­
49
yrs
0.000267
0.0%
Adults
50+
yrs
0.000287
0.0%
Females
13­
49
yrs
0.000257
0.0%

­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
Imazapyr
Dietary
Exposure
Assessment
DP
Barcode:
D288806
PC
Code:
128821
Page:
7
of
7
ATTACHMENT
2.
RESIDUE
FILE
LISTING
FOR
IMAZAPYR.

Filename:
C:\
DEEMFCID\
128821.
r98
Chemical:
Imazapyr
RfD(
Chronic):
2.5
mg/
kg
bw/
day
NOEL(
Chronic):
250
mg/
kg
bw/
day
RfD(
Acute):
0
mg/
kg
bw/
day
NOEL(
Acute):
0
mg/
kg
bw/
day
Date
created/
last
modified:
03­
20­
2003/
14:
11:
01/
8
Program
ver.
1.30
Comment:
PP#
0F6166
(
grass
&
aquatic
uses)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
EPA
Crop
Def
Res
Adj.
Factors
Comment
Code
Grp
Commodity
Name
(
ppm)
#
1
#
2
­­­­­­­­
­­­­
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
­­­­­­­­­­
­­­­­­
­­­­­­
­­­­­­­
21000440
M
Beef,
meat
0.050000
1.000
1.000
N
PP#
0F6166
21000441
M
Beef,
meat­
babyfood
0.050000
1.000
1.000
N
PP#
0F6166
21000450
M
Beef,
meat,
dried
0.050000
1.920
1.000
N
PP#
0F6166
21000460
M
Beef,
meat
byproducts
0.050000
1.000
1.000
N
PP#
0F6166
21000461
M
Beef,
meat
byproducts­
babyfood
0.050000
1.000
1.000
N
PP#
0F6166
21000470
M
Beef,
fat
0.050000
1.000
1.000
N
PP#
0F6166
21000471
M
Beef,
fat­
babyfood
0.050000
1.000
1.000
N
PP#
0F6166
21000480
M
Beef,
kidney
0.200000
1.000
1.000
N
PP#
0F6166
21000490
M
Beef,
liver
0.050000
1.000
1.000
N
PP#
0F6166
21000491
M
Beef,
liver­
babyfood
0.050000
1.000
1.000
N
PP#
0F6166
15001200
15
Corn,
field,
flour
0.050000
1.000
1.000
PP#
6F4641
15001201
15
Corn,
field,
flour­
babyfood
0.050000
1.000
1.000
PP#
6F4641
15001210
15
Corn,
field,
meal
0.050000
1.000
1.000
PP#
6F4641
15001211
15
Corn,
field,
meal­
babyfood
0.050000
1.000
1.000
PP#
6F4641
15001220
15
Corn,
field,
bran
0.050000
1.000
1.000
PP#
6F4641
15001230
15
Corn,
field,
starch
0.050000
1.000
1.000
PP#
6F4641
15001231
15
Corn,
field,
starch­
babyfood
0.050000
1.000
1.000
PP#
6F4641
15001240
15
Corn,
field,
syrup
0.050000
1.000
1.000
PP#
6F4641
15001241
15
Corn,
field,
syrup­
babyfood
0.050000
1.000
1.000
PP#
6F4641
15001250
15
Corn,
field,
oil
0.050000
1.000
1.000
PP#
6F4641
15001251
15
Corn,
field,
oil­
babyfood
0.050000
1.000
1.000
PP#
6F4641
80001570
F
Fish­
freshwater
finfish
1.000000
1.000
1.000
N
PP#
0F6166
80001580
F
Fish­
freshwater
finfish,
farm
ra
1.000000
1.000
1.000
N
PP#
0F6166
80001590
F
Fish­
saltwater
finfish,
tuna
1.000000
1.000
1.000
N
PP#
0F6166
80001600
F
Fish­
saltwater
finfish,
other
1.000000
1.000
1.000
N
PP#
0F6166
80001610
F
Fish­
shellfish,
crustacean
0.100000
1.000
1.000
N
PP#
0F6166
80001620
F
Fish­
shellfish,
mollusc
0.100000
1.000
1.000
N
PP#
0F6166
23001690
M
Goat,
meat
0.050000
1.000
1.000
N
PP#
0F6166
23001700
M
Goat,
meat
byproducts
0.050000
1.000
1.000
N
PP#
0F6166
23001710
M
Goat,
fat
0.050000
1.000
1.000
N
PP#
0F6166
23001720
M
Goat,
kidney
0.200000
1.000
1.000
N
PP#
0F6166
23001730
M
Goat,
liver
0.050000
1.000
1.000
N
PP#
0F6166
24001890
M
Horse,
meat
0.050000
1.000
1.000
N
PP#
0F6166
28002210
M
Meat,
game
0.050000
1.000
1.000
N
PP#
0F6166
27002220
D
Milk,
fat
0.010000
1.000
1.000
N
PP#
0F6166
27002221
D
Milk,
fat
­
baby
food/
infant
for
0.010000
1.000
1.000
N
PP#
0F6166
27012230
D
Milk,
nonfat
solids
0.010000
1.000
1.000
N
PP#
0F6166
27012231
D
Milk,
nonfat
solids­
baby
food/
in
0.010000
1.000
1.000
N
PP#
0F6166
27022240
D
Milk,
water
0.010000
1.000
1.000
N
PP#
0F6166
27022241
D
Milk,
water­
babyfood/
infant
form
0.010000
1.000
1.000
N
PP#
0F6166
27032251
D
Milk,
sugar
(
lactose)­
baby
food/
0.010000
1.000
1.000
N
PP#
0F6166
26003390
M
Sheep,
meat
0.050000
1.000
1.000
N
PP#
0F6166
26003391
M
Sheep,
meat­
babyfood
0.050000
1.000
1.000
N
PP#
0F6166
26003400
M
Sheep,
meat
byproducts
0.050000
1.000
1.000
N
PP#
0F6166
26003410
M
Sheep,
fat
0.050000
1.000
1.000
N
PP#
0F6166
26003411
M
Sheep,
fat­
babyfood
0.050000
1.000
1.000
N
PP#
0F6166
26003420
M
Sheep,
kidney
0.200000
1.000
1.000
N
PP#
0F6166
26003430
M
Sheep,
liver
0.050000
1.000
1.000
N
PP#
0F6166
