Document ID: EPA-HQ-OPP-2003-0266-0001
Agency: epa
Document Type: Notice
Title: Imazapyr; Notice of Filing a Pesticide Petition to Establish a Tolerance for a Certain Pesticide Chemical in or on Food
Posted Date: 2003-08-13T04:00Z

48362
Federal
Register
/
Vol.
68,
No.
156
/
Wednesday,
August
13,
2003
/
Notices
Nominations
are
requested
within
60
days
of
this
notice,
and
may
be
submitted
online
at
www.
epa.
gov/
iris/
whatsnew/
2004nominations
or
by
mail
or
electronic
mail.
Submissions
by
mail
may
be
made
to
the
IRIS
Submission
Desk,
c/
o
ASRC,
6301
Ivy
Lane,
Suite
300,
Greenbelt,
MD
20770.
Please
send
two
copies,
with
one
copy
unbound.
Alternatively,
nominations
may
be
sent
electronically
to
IRIS.
desk@
epa.
gov.
Electronic
information
must
be
submitted
in
WordPerfect
format
or
as
an
ASCII
file.
Information
also
will
be
accepted
on
3.5 
floppy
disks
or
CD.
The
IRIS
Submission
Desk
will
acknowledge
receipt
of
your
information.

Dated:
August
8,
2003.
Peter
W.
Preuss,
Director,
National
Center
for
Environmental
Assessment.
[
FR
Doc.
03
 
20528
Filed
8
 
12
 
03;
8:
45
am]

BILLING
CODE
6560
 
50
 
P
ENVIRONMENTAL
PROTECTION
AGENCY
[
OPP
 
2003
 
0266;
FRL
 
7321
 
7]

Imazapyr;
Notice
of
Filing
a
Pesticide
Petition
to
Establish
a
Tolerance
for
a
Certain
Pesticide
Chemical
in
or
on
Food
AGENCY:
Environmental
Protection
Agency
(
EPA).

ACTION:
Notice.

SUMMARY:
This
notice
announces
the
initial
filing
of
a
pesticide
petition
proposing
the
establishment
of
regulations
for
residues
of
a
certain
pesticide
chemical
in
or
on
various
food
commodities.

DATES:
Comments,
identified
by
docket
ID
number
OPP
 
2003
 
0266,
must
be
received
on
or
before
September
12,
2003.

ADDRESSES:
Comments
may
be
submitted
electronically,
by
mail,
or
through
hand
delivery/
courier.
Follow
the
detailed
instructions
as
provided
in
Unit
I.
of
the
SUPPLEMENTARY
INFORMATION.

FOR
FURTHER
INFORMATION
CONTACT:
Jim
Tompkins,
Registration
Division
(
7505C),
Office
of
Pesticide
Programs,
Environmental
Protection
Agency,
1200
Pennsylvania
Ave.,
NW.,
Washington,
DC
20460
 
0001;
telephone
number:
(
703)
305
 
5697;
e­
mail
address:
Tompkins.
Jim@
epa.
gov.

SUPPLEMENTARY
INFORMATION:
I.
General
Information
A.
Does
this
Action
Apply
to
Me?

You
may
be
potentially
affected
by
this
action
if
you
are
an
agricultural
producer,
food
manufacturer,
or
pesticide
manufacturer.
Potentially
affected
entities
may
include,
but
are
not
limited
to:
 
Crop
production
(
NAICS
111)
 
Animal
production
(
NAICS
112)
 
Food
manufacturing
(
NAICS
311)
 
Pesticide
manufacturing
(
NAICS
32532)
This
listing
is
not
intended
to
be
exhaustive,
but
rather
provides
a
guide
for
readers
regarding
entities
likely
to
be
affected
by
this
action.
Other
types
of
entities
not
listed
in
this
unit
could
also
be
affected.
The
North
American
Industrial
Classification
System
(
NAICS)
codes
have
been
provided
to
assist
you
and
others
in
determining
whether
this
action
might
apply
to
certain
entities.
If
you
have
any
questions
regarding
the
applicability
of
this
action
to
a
particular
entity,
consult
the
person
listed
under
FOR
FURTHER
INFORMATION
CONTACT.

B.
How
Can
I
Get
Copies
of
this
Document
and
Other
Related
Information?

1.
Docket.
EPA
has
established
an
official
public
docket
for
this
action
under
docket
identification
(
ID)
number
OPP
 
2003
 
0266.
The
official
public
docket
consists
of
the
documents
specifically
referenced
in
this
action,
any
public
comments
received,
and
other
information
related
to
this
action.
Although
a
part
of
the
official
docket,
the
public
docket
does
not
include
Confidential
Business
Information
(
CBI)
or
other
information
whose
disclosure
is
restricted
by
statute.
The
official
public
docket
is
the
collection
of
materials
that
is
available
for
public
viewing
at
the
Public
Information
and
Records
Integrity
Branch
(
PIRIB),
Rm.
119,
Crystal
Mall
#
2,
1921
Jefferson
Davis
Hwy.,
Arlington,
VA.
This
docket
facility
is
open
from
8:
30
a.
m.
to
4
p.
m.,
Monday
through
Friday,
excluding
legal
holidays.
The
docket
telephone
number
is
(
703)
305
 
5805.
2.
Electronic
access.
You
may
access
this
Federal
Register
document
electronically
through
the
EPA
Internet
under
the
``
Federal
Register''
listings
at
http://
www.
epa.
gov/
fedrgstr/.
An
electronic
version
of
the
public
docket
is
available
through
EPA's
electronic
public
docket
and
comment
system,
EPA
Dockets.
You
may
use
EPA
Dockets
at
http://
www.
epa.
gov/
edocket/
to
submit
or
view
public
comments,
access
the
index
listing
of
the
contents
of
the
official
public
docket,
and
to
access
those
documents
in
the
public
docket
that
are
available
electronically.
Although
not
all
docket
materials
may
be
available
electronically,
you
may
still
access
any
of
the
publicly
available
docket
materials
through
the
docket
facility
identified
in
Unit
I.
B.
1.
Once
in
the
system,
select
``
search,''
then
key
in
the
appropriate
docket
ID
number.
Certain
types
of
information
will
not
be
placed
in
the
EPA
Dockets.
Information
claimed
as
CBI
and
other
information
whose
disclosure
is
restricted
by
statute,
which
is
not
included
in
the
official
public
docket,
will
not
be
available
for
public
viewing
in
EPA's
electronic
public
docket.
EPA's
policy
is
that
copyrighted
material
will
not
be
placed
in
EPA's
electronic
public
docket
but
will
be
available
only
in
printed,
paper
form
in
the
official
public
docket.
To
the
extent
feasible,
publicly
available
docket
materials
will
be
made
available
in
EPA's
electronic
public
docket.
When
a
document
is
selected
from
the
index
list
in
EPA
Dockets,
the
system
will
identify
whether
the
document
is
available
for
viewing
in
EPA's
electronic
public
docket.
Although
not
all
docket
materials
may
be
available
electronically,
you
may
still
access
any
of
the
publicly
available
docket
materials
through
the
docket
facility
identified
in
Unit
I.
B.
EPA
intends
to
work
towards
providing
electronic
access
to
all
of
the
publicly
available
docket
materials
through
EPA's
electronic
public
docket.
For
public
commenters,
it
is
important
to
note
that
EPA's
policy
is
that
public
comments,
whether
submitted
electronically
or
in
paper,
will
be
made
available
for
public
viewing
in
EPA's
electronic
public
docket
as
EPA
receives
them
and
without
change,
unless
the
comment
contains
copyrighted
material,
CBI,
or
other
information
whose
disclosure
is
restricted
by
statute.
When
EPA
identifies
a
comment
containing
copyrighted
material,
EPA
will
provide
a
reference
to
that
material
in
the
version
of
the
comment
that
is
placed
in
EPA's
electronic
public
docket.
The
entire
printed
comment,
including
the
copyrighted
material,
will
be
available
in
the
public
docket.
Public
comments
submitted
on
computer
disks
that
are
mailed
or
delivered
to
the
docket
will
be
transferred
to
EPA's
electronic
public
docket.
Public
comments
that
are
mailed
or
delivered
to
the
docket
will
be
scanned
and
placed
in
EPA's
electronic
public
docket.
Where
practical,
physical
objects
will
be
photographed,
and
the
photograph
will
be
placed
in
EPA's
electronic
public
docket
along
with
a
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Federal
Register
/
Vol.
68,
No.
156
/
Wednesday,
August
13,
2003
/
Notices
brief
description
written
by
the
docket
staff.

C.
How
and
To
Whom
Do
I
Submit
Comments?
You
may
submit
comments
electronically,
by
mail,
or
through
hand
delivery/
courier.
To
ensure
proper
receipt
by
EPA,
identify
the
appropriate
docket
ID
number
in
the
subject
line
on
the
first
page
of
your
comment.
Please
ensure
that
your
comments
are
submitted
within
the
specified
comment
period.
Comments
received
after
the
close
of
the
comment
period
will
be
marked
``
late.''
EPA
is
not
required
to
consider
these
late
comments.
If
you
wish
to
submit
CBI
or
information
that
is
otherwise
protected
by
statute,
please
follow
the
instructions
in
Unit
I.
D.
Do
not
use
EPA
Dockets
or
e­
mail
to
submit
CBI
or
information
protected
by
statute.
1.
Electronically.
If
you
submit
an
electronic
comment
as
prescribed
in
this
unit,
EPA
recommends
that
you
include
your
name,
mailing
address,
and
an
email
address
or
other
contact
information
in
the
body
of
your
comment.
Also
include
this
contact
information
on
the
outside
of
any
disk
or
CD
ROM
you
submit,
and
in
any
cover
letter
accompanying
the
disk
or
CD
ROM.
This
ensures
that
you
can
be
identified
as
the
submitter
of
the
comment
and
allows
EPA
to
contact
you
in
case
EPA
cannot
read
your
comment
due
to
technical
difficulties
or
needs
further
information
on
the
substance
of
your
comment.
EPA's
policy
is
that
EPA
will
not
edit
your
comment,
and
any
identifying
or
contact
information
provided
in
the
body
of
a
comment
will
be
included
as
part
of
the
comment
that
is
placed
in
the
official
public
docket,
and
made
available
in
EPA's
electronic
public
docket.
If
EPA
cannot
read
your
comment
due
to
technical
difficulties
and
cannot
contact
you
for
clarification,
EPA
may
not
be
able
to
consider
your
comment.
i.
EPA
Dockets.
Your
use
of
EPA's
electronic
public
docket
to
submit
comments
to
EPA
electronically
is
EPA's
preferred
method
for
receiving
comments.
Go
directly
to
EPA
Dockets
at
http://
www.
epa.
gov/
edocket,
and
follow
the
online
instructions
for
submitting
comments.
Once
in
the
system,
select
``
search,''
and
then
key
in
docket
ID
number
OPP
 
2003
 
0266.
The
system
is
an
``
anonymous
access''
system,
which
means
EPA
will
not
know
your
identity,
e­
mail
address,
or
other
contact
information
unless
you
provide
it
in
the
body
of
your
comment.
ii.
E­
mail.
Comments
may
be
sent
by
e­
mail
to
opp­
docket@
epa.
gov,
Attention:
Docket
ID
Number
OPP
 
2003
 
0266.
In
contrast
to
EPA's
electronic
public
docket,
EPA's
e­
mail
system
is
not
an
``
anonymous
access''
system.
If
you
send
an
e­
mail
comment
directly
to
the
docket
without
going
through
EPA's
electronic
public
docket,
EPA's
e­
mail
system
automatically
captures
your
e­
mail
address.
E­
mail
addresses
that
are
automatically
captured
by
EPA's
e­
mail
system
are
included
as
part
of
the
comment
that
is
placed
in
the
official
public
docket,
and
made
available
in
EPA's
electronic
public
docket.
iii.
Disk
or
CD
ROM.
You
may
submit
comments
on
a
disk
or
CD
ROM
that
you
mail
to
the
mailing
address
identified
in
Unit
I.
C.
2.
These
electronic
submissions
will
be
accepted
in
WordPerfect
or
ASCII
file
format.
Avoid
the
use
of
special
characters
and
any
form
of
encryption.
2.
By
mail.
Send
your
comments
to:
Public
Information
and
Records
Integrity
Branch
(
PIRIB)
(
7502C),
Office
of
Pesticide
Programs
(
OPP),
Environmental
Protection
Agency,
1200
Pennsylvania
Ave.,
NW.,
Washington,
DC
20460
 
0001,
Attention:
Docket
ID
Number
OPP
 
2003
 
0266.
3.
By
hand
delivery
or
courier.
Deliver
your
comments
to:
Public
Information
and
Records
Integrity
Branch
(
PIRIB),
Office
of
Pesticide
Programs
(
OPP),
Environmental
Protection
Agency,
Rm.
119,
Crystal
Mall
#
2,
1921
Jefferson
Davis
Hwy.,
Arlington,
VA,
Attention:
Docket
ID
Number
OPP
 
2003
 
0266.
Such
deliveries
are
only
accepted
during
the
docket's
normal
hours
of
operation
as
identified
in
Unit
I.
B.
1.

D.
How
Should
I
Submit
CBI
To
the
Agency?
Do
not
submit
information
that
you
consider
to
be
CBI
electronically
through
EPA's
electronic
public
docket
or
by
e­
mail.
You
may
claim
information
that
you
submit
to
EPA
as
CBI
by
marking
any
part
or
all
of
that
information
as
CBI
(
if
you
submit
CBI
on
disk
or
CD
ROM,
mark
the
outside
of
the
disk
or
CD
ROM
as
CBI
and
then
identify
electronically
within
the
disk
or
CD
ROM
the
specific
information
that
is
CBI).
Information
so
marked
will
not
be
disclosed
except
in
accordance
with
procedures
set
forth
in
40
CFR
part
2.
In
addition
to
one
complete
version
of
the
comment
that
includes
any
information
claimed
as
CBI,
a
copy
of
the
comment
that
does
not
contain
the
information
claimed
as
CBI
must
be
submitted
for
inclusion
in
the
public
docket
and
EPA's
electronic
public
docket.
If
you
submit
the
copy
that
does
not
contain
CBI
on
disk
or
CD
ROM,
mark
the
outside
of
the
disk
or
CD
ROM
clearly
that
it
does
not
contain
CBI.
Information
not
marked
as
CBI
will
be
included
in
the
public
docket
and
EPA's
electronic
public
docket
without
prior
notice.
If
you
have
any
questions
about
CBI
or
the
procedures
for
claiming
CBI,
please
consult
the
person
listed
under
FOR
FURTHER
INFORMATION
CONTACT.

E.
What
Should
I
Consider
as
I
Prepare
My
Comments
for
EPA?
You
may
find
the
following
suggestions
helpful
for
preparing
your
comments:
1.
Explain
your
views
as
clearly
as
possible.
2.
Describe
any
assumptions
that
you
used.
3.
Provide
copies
of
any
technical
information
and/
or
data
you
used
that
support
your
views.
4.
If
you
estimate
potential
burden
or
costs,
explain
how
you
arrived
at
the
estimate
that
you
provide.
5.
Provide
specific
examples
to
illustrate
your
concerns.
6.
Make
sure
to
submit
your
comments
by
the
deadline
in
this
notice.
7.
To
ensure
proper
receipt
by
EPA,
be
sure
to
identify
the
docket
ID
number
assigned
to
this
action
in
the
subject
line
on
the
first
page
of
your
response.
You
may
also
provide
the
name,
date,
and
Federal
Register
citation.

II.
What
Action
is
the
Agency
Taking?

EPA
has
received
a
pesticide
petition
as
follows
proposing
the
establishment
and/
or
amendment
of
regulations
for
residues
of
a
certain
pesticide
chemical
in
or
on
various
food
commodities
under
section
408
of
the
Federal
Food,
Drug,
and
Cosmetic
Act
(
FFDCA),
21
U.
S.
C.
346a.
EPA
has
determined
that
this
petition
contains
data
or
information
regarding
the
elements
set
forth
in
FFDCA
section
408(
d)(
2);
however,
EPA
has
not
fully
evaluated
the
sufficiency
of
the
submitted
data
at
this
time
or
whether
the
data
support
granting
of
the
petition.
Additional
data
may
be
needed
before
EPA
rules
on
the
petition.

List
of
Subjects
Environmental
protection,
Agricultural
commodities,
Feed
additives,
Food
additives,
Pesticides
and
pests,
Reporting
and
recordkeeping
requirements.

Dated:
August
7,
2003.
Debra
Edwards,
Director,
Registration
Division,
Office
of
Pesticide
Programs.

Summary
of
Petition
The
petitioner
summary
of
the
pesticide
petition
is
printed
below
as
required
by
FFDCA
section
408(
d)(
3).
The
summary
of
the
petition
was
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Federal
Register
/
Vol.
68,
No.
156
/
Wednesday,
August
13,
2003
/
Notices
prepared
by
the
petitioner
and
represents
the
view
of
the
petitioner.
The
petition
summary
announces
the
availability
of
a
description
of
the
analytical
methods
available
to
EPA
for
the
detection
and
measurement
of
the
pesticide
chemical
residues
or
an
explanation
of
why
no
such
method
is
needed.

BASF
Corporation
PP
0F6166
EPA
has
received
a
pesticide
petition
(
PP
0F6166)
from
BASF,
26
Davis
Drive,
Research
Triangle
Park,
NC
27709
 
3528
proposing,
pursuant
to
section
408(
d)
of
the
Federal
Food,
Drug,
and
Cosmetic
Act
(
FFDCA),
21
U.
S.
C.
346a(
d),
to
amend
40
CFR
part
180
by
establishing
a
tolerance
for
residues
of
imazapyr
[
2­
[
4,5­
dihydro­
4­
methyl­
4­(
1­
methylethyl)­
5­
oxo­
lH­
imidazol­
2­
yl]­
3­
pyridinecarboxylic
acid],
applied
as
the
isopropylamine
salt,
in
or
on
the
raw
agricultural
commodity
on
grass
forage
at
125
parts
per
million
(
ppm)
and
hay
at
35
ppm,
fish
at
1
ppm,
shellfish
at
0.1
ppm,
milk
at
0.01
ppm,
and
kidney
at
0.5
ppm,
meat
by­
products
other
than
kidney
at
0.05
ppm,
meat
at
0.05
ppm,
and
fat
at
0.05
ppm
of
cattle,
sheep,
goats,
and
horses.
EPA
has
determined
that
the
petition
contains
data
or
information
regarding
the
elements
set
forth
in
section
408(
d)(
2)
of
the
FFDCA;
however,
EPA
has
not
fully
evaluated
the
sufficiency
of
the
submitted
data
at
this
time
or
whether
the
data
supports
granting
of
the
petition.
Additional
data
may
be
needed
before
EPA
rules
on
the
petition.

A.
Residue
Chemistry
1.
Plant
metabolism
 
i.
Bermudagrass.
Radiolabeled
imazapyr
was
applied
at
1.5
lb
acid
equivalents/
acre
(
ae)/
A
to
field­
grown
bermudagrass.
Parent
imazapyr
accounted
for
the
majority
of
the
total
radioactive
residue
(
TRR)
in
all
harvested
samples.
No
metabolites
were
identified
which
require
regulation.
ii.
Ruminant.
Goats
were
dosed
with
radiolabeled
imazapyr
at
17.7
ppm,
42.5
ppm,
or
47
ppm
dietary
equivalents
for
7
days.
As
assessed
for
goats
receiving
the
17.7
or
42.5
ppm
doses,
TRR
in
fat,
liver
and
leg
and
loin
muscle
were
nondetectable
<
0.05
ppm.
TRR
in
milk
were
a
maximum
of
0.01,
0.02,
and
0.02
ppm
for
the
three
goats,
respectively,
while
TRR
in
kidney
were
0.08,
0.11,
and
0.08
ppm,
respectively.
Of
these
residues,
parent
imazapyr
accounted
for
50
 
66%
of
the
TRR
in
milk
and
82
 
95%
of
the
TRR
in
kidney.
No
metabolites
were
identified
which
require
regulation.
iii.
Confined
crop
rotation.
Radiolabeled
imazapyr
was
applied
to
soil
at
a
rate
of
0.79
lb
ae/
A.
Root
(
carrot),
lettuce
(
leafy
vegetables),
and
wheat
(
cereal
grains),
were
planted
at
330
through
540
days;
shorter
intervals
were
not
required
as
rangeland
and
pastures
are
not
normally
rotated
to
other
crops.
The
TRR
in
all
harvested
samples
were
<
0.02
ppm
and
the
major
extractable
component
of
these
residues
was
parent
imazapyr.
Therefore,
there
is
no
reasonable
expectation
of
inadvertent
residues
in
rotational
crops
planted
12
months
after
application.
2.
Analytical
method.
M
3023
is
a
reliable
capillary
electrophoresis
method
with
ultraviolet
(
CE/
UV)
detection
for
the
determination
of
imazapyr
residues
in
grass
forage
and
grass
hay.
M
3184
is
a
reliable
CE/
UV
method
for
the
determination
of
imazapyr
residues
in
meat,
kidney,
other
meat
byproducts,
and
fat
of
cattle,
sheep,
goats,
and
horses.
M
3075
is
a
reliable
CE/
UV
method
for
the
determination
of
imazapyr
residues
in
milk.
M
3066
is
a
reliable
CE/
UV
method
for
the
determination
of
imazapyr
residues
in
fish
and
shellfish.
3.
Magnitude
of
residues
 
i.
Grass.
Imazapyr
was
applied
at
a
nominal
rate
of
0.75
lb
ae/
A
to
bluegrass,
bermudagrass,
tall
fescue,
and
bromegrass
for
a
total
of
14
field
trials.
Residues
of
imazapyr
were
reached
a
maximum
of
98
ppm
in
grass
forage
immediately
after
treatment
and
27
ppm
upon
drying
to
grass
hay
cut
7
days
after
treatment.
Therefore,
tolerances
of
125
ppm
in/
on
grass
forage
and
35
ppm
in/
on
grass
hay
are
proposed.
ii.
Ruminants.
Lactating
dairy
cows
were
dosed
orally
each
day
for
28
or
29
consecutive
days
at
feed
equivalents
of
0,
58,
157,
607,
and
1,680
milligrams
(
mg)
imazapyr
per
kilogram
(
kg)
dry
matter
consumed.
The
58
mg/
kg
dose
is
equivalent
to
1.4
times
the
anticipated
dietary
burden
for
the
worst­
case
cattle
diet
where
10%
of
the
grass
received
an
imazapyr
spot
treatment,
the
proposed
label
use
for
range
and
pasture
grasses.
At
58
mg/
kg,
imazapyr
residues
in
milk
were
<
0.01
ppm;
residues
in
muscle,
fat,
and
liver
were
<
0.05
ppm;
and
residues
in
kidney
averaged
0.25
ppm.
Furthermore,
imazapyr
residues
in
milk
were
shown
not
to
be
concentrated
into
milk
fat.
Therefore,
the
following
tolerances
for
imazapyr
residues
in
cattle,
sheep,
goats,
and
horses
are
proposed:
Milk
at
0.01
ppm;
meat
byproducts
(
except
kidney)
at
0.05
ppm;
meat
at
0.05
ppm;
fat
at
0.05
ppm;
and
kidney
at
0.5
ppm.
iii.
Fish
and
shellfish.
Imazapyr
was
applied
at
1.6
lb
ae/
A
to
two
ponds
containing
fish
and
aquatic
invertebrates.
Imazapyr
residues
were
observed
from
the
organisms
collected
from
the
treated
ponds
at
only
one
site
and
only
in
the
3­
hour­
after­
treatment
samples.
Average
residues
from
these
samples
were:
Bluegill,
0.636
ppm;
tilapia,
0.233
ppm;
catfish,
0.068
ppm;
crayfish,
0.059
ppm.
In
a
separate
study,
freshwater
clams
were
exposed
to
a
dose
of
imazapyr
equivalent
to
1.5
lb
ae/
A
as
applied
to
a
2.2­
foot
deep
pond;
residues
of
imazapyr
in
these
clams
remained
<
0.05
ppm
at
all
intervals
evaluated
(
up
to
28
days
posttreatment
Given
these
results,
tolerances
for
imazapyr
are
proposed
at
1
ppm
for
fish
and
0.1
ppm
for
shellfish.

B.
Toxicological
Profile
1.
Acute
toxicity.
Based
on
a
battery
of
acute
toxicity
studies,
imazapyr
has
been
placed
in
toxicity
category
I
for
eye
irritation,
category
IV
for
oral
LD50
and
primary
dermal
irritation,
and
category
III
for
dermal
LD50
and
inhalation
LC50.
Imazapyr
was
a
non­
sensitizer
when
tested
for
dermal
sensitization
(
Buehler
Method).
2.
Genotoxicity.
Studies
on
gene
mutation
and
other
genotoxic
effects,
Ames
Salmonella
Assay,
CHO/
HGPRT
Point
Mutation
Assay,
in
vitro
CHO
cell
chromosome
aberration
assay,
dominant
lethal
assay,
and
unscheduled
DNA
synthesis
(
UDS)
in
primary
rat
hepatocytes
yielded
negative
results.
3.
Reproductive
and
developmental
toxicity
 
i.
For
a
rat
developmental
toxicity
study
at
doses
of
0,
100,
300,
or
1,000
mg/
kg
body
weight/
day
(
b.
w./
day),
the
only
clinical
sign
of
toxicity
was
salivation
in
gravid
dams
at
1,000
mg/
kg
b.
w./
day.
The
No­
Observed­
Adverse­
Effect
Level
(
NOAEL)
for
maternal
toxicity
is
300
mg/
kg
b.
w./
day.
There
were
no
developmental
findings
in
this
study
up
to
the
limit
dose
of
1,000
mg/
kg
b.
w./
day,
the
highest
dose
tested
(
HDT).
ii.
For
a
rabbit
development
toxicity
study
at
doses
of
0,
25,
100,
and
400
mg/
kg
b.
w./
day,
the
maternal
and
developmental
NOAEL
is
400
mg/
kg
b.
w./
day
HDT.
Doses
were
based
on
pilot
range­
finder
study,
which
tested
at
0,
250,
500,
1,000,
and
2,000
mg/
kg
b.
w./
day.
The
only
toxic
effect
observed
was
increased
salivation
at
1,000
and
2,000
mg/
kg
b.
w./
day.
iii.
A
2
 
generation
rat
reproduction
study
at
doses
of
0,
1,000,
5,000,
or
10,000
ppm
yielded
a
NOAEL
of
10,000
ppm
highest
concentration
tested
(
HCT)
(
800
mg/
kg
b.
w./
day
for
males,
980
mg/
kg
b.
w./
day
for
females,
as
based
on
food
consumption
data).
4.
Subchronic
toxicity
 
i.
A
90
 
day
dietary
study
in
rats
at
doses
of
0,
15,000,
or
20,000
ppm
resulted
in
a
VerDate
jul<
14>
2003
15:
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12,
2003
Jkt
200001
PO
00000
Frm
00031
Fmt
4703
Sfmt
4703
E:\
FR\
FM\
13AUN1.
SGM
13AUN1
48365
Federal
Register
/
Vol.
68,
No.
156
/
Wednesday,
August
13,
2003
/
Notices
NOAEL
of
20,000
ppm
HCT
(
approximately
1,695
mg/
kg
b.
w./
day
for
males,
1,785
mg/
kg
b.
w./
day
for
females,
as
based
on
food
consumption
data).
ii.
A
21
 
day
rabbit
dermal
toxicity
study
at
doses
of
0,
100,
200,
or
400
mg/
kg
b.
w./
day
resulted
with
the
NOAEL
of
400
mg/
kg
b.
w./
day
HDT.
5.
Chronic
toxicity
 
i.
A
1
 
year
chronic
toxicity
study
in
dogs
at
doses
of
0,
1,000,
5,000,
or
10,000
ppm
yielded
a
NOAEL
of
10,000
ppm
HCT
(
equivalent
to
250
mg/
kg
b.
w./
day).
ii.
A
2
 
year
chronic
toxicity/
carcinogenicity
study
in
rats
at
doses
of
0,
1,000,
5,000,
or
10,000
ppm
provided
NOAELs
for
both
systemic
toxicity
and
oncogenicity
of
10,000
ppm
HCT
(
approximately
500
mg/
kg
b.
w./
day
for
males,
640
mg/
kg
b.
w./
day
for
females,
as
based
on
food
consumption
data).
iii.
An
18
 
month
oncogenicity
study
in
mice
at
doses
of
0,
1,000,
5,000,
or
10,000
ppm
provided
NOAELs
for
both
systemic
toxicity
and
oncogenicity
of
10,000
ppm
HCT
(
equivalent
to
1,500
mg/
kg
b.
w./
day).
6.
Animal
metabolism.
Results
from
a
rat
metabolism
study
indicated
that
imazapyr
was
rapidly
absorbed
and
excreted
by
7
days
post­
dosing,
with
the
majority
of
the
administered
14C­
label
(
90%)
eliminated
in
the
urine
within
48
hours.
Metabolite
characterization
studies
showed
that
essentially
all
the
test
material
was
excreted
unchanged.
Two
minor
metabolites
were
detected
in
the
urine
or
feces
of
treated
rats;
however,
their
contribution
combined
was
less
than
or
equal
to
0.5%
of
the
administered
dose.
An
additional
12
unidentified
metabolites
were
isolated,
but
they
contributed
less
than
3%
of
the
total
dose.
7.
Metabolite
toxicology.
There
were
no
metabolites
identified
in
plant
or
animal
commodities
which
require
regulation.
8.
Endocrine
disruption.
There
is
sufficient
data
from
the
2
 
generation
rat
reproduction
study
as
well
as
from
the
subchronic
(
90
 
day)
rat
feeding
study
and
chronic
feeding
studies
in
the
dog
(
1
 
year),
rat
(
24
 
month),
and
mouse
(
18
 
month),
to
determine
whether
imazapyr
has
potential
estrogenic
properties
or
causes
other
endocrine
effects.
The
collective
data
from
these
studies,
indicate
that
imazapyr
is
not
associated
with
any
treatment­
related
estrogenic
or
endocrine
effects.
The
2
 
generation
rat
reproduction
study,
conducted
at
dietary
concentrations
up
to
10,000
ppm,
showed
no
treatment­
related
effects
on
reproductive
performance
(
including
estrous
cycle
data,
mating
indices,
pregnancy
rates,
fertility
indices,
gestational
length,
and
gestation
indices)
or
on
pup
growth
and
development
from
parturition
to
adulthood
for
both
litter
intervals.
Histopathological
examinations
of
the
testes,
epididymides,
prostate
gland,
and
seminal
vesicles,
were
conducted
for
high­
dose
and
control
P1
and
F1
adult
males.
Histopathological
examinations
of
the
mammary
gland,
ovaries,
uterus
(
corpus
and
cervix),
and
vagina,
were
conducted
for
high­
dose
and
control
P1
and
F1
adult
females.
In
addition,
for
F2b
pups,
histopathological
examinations
of
the
adrenal
glands,
pancreatic
islets,
pituitary
gland,
thyroid
gland,
parathyroid
glands,
testes,
epididymides,
prostate
gland,
seminal
vesicles,
mammary
gland,
ovaries,
uterus
(
corpus
and
cervix),
and
vagina,
were
conducted.
For
all
of
these
tissue
examinations,
no
treatmentrelated
microscopic
findings
were
observed
in
either
males
or
females.
Further,
no
treatment­
related
macroscopic
findings
were
observed
for
either
parental
or
pup
generations.
Organ
weight
data
and
histopathological
examinations
from
the
subchronic
(
90
 
day)
rat
feeding
study
and
chronic
feeding
studies
in
the
dog
(
1
 
year),
rat
(
24
 
month),
and
mouse
(
18
 
month),
may
also
be
utilized
to
determine
whether
imazapyr
has
potential
estrogenic
properties
or
causes
other
endocrine
effects.
Absolute
and
relative
weights
of
the
adrenal
glands
(
not
measured
in
the
dog
study),
pituitary
gland,
thyroid/
parathyroid
gland,
ovaries,
and
testes
(
with/
without
epididymides)
were
recorded
for
animals
at
the
interim
(
if
applicable)
and
terminal
sacrifice
periods
in
these
studies.
In
addition,
detailed
macroscopic
and
microscopic
examinations
of
the
following
organs
were
performed:
Pituitary
gland,
thyroid
gland,
parathyroid
glands,
pancreatic
islets,
adrenal
glands,
testes,
epididymides,
prostate
gland,
seminal
vesicles
(
not
performed
in
the
dog
study),
mammary
gland,
ovaries,
uterus
(
corpus
and
cervix),
and
vagina.
No
information
was
found
from
the
organ
weight
data
or
macroscopic
and
microscopic
examinations,
from
the
subchronic
(
90
 
day)
rat
feeding
study
and
chronic
feeding
studies
in
the
dog
(
1
 
year),
rat
(
24
 
month),
and
mouse
(
18
 
month),
that
suggests
that
imazapyr
is
associated
with
any
treatment­
related
estrogenic
effects
or
effects
on
the
endocrine
system.

C.
Aggregate
Exposure
1.
Dietary
exposure
 
i.
Food
 
a.
Acute
dietary
exposure.
An
acute
dietary
risk
assessment
is
not
required
because
no
acute
toxicological
endpoints
were
identified
by
the
EPA
for
imazapyr.
b.
Chronic
dietary
exposure.
Novigen
Sciences,
Inc.
conducted
a
Tier
1
assessment
of
potential
chronic
dietary
exposure
from
the
proposed
uses
of
imazapyr
for
weed
control
in
pasture/
range
grasses
and
for
aquatic
weed
control.
These
uses
may
result
in
dietary
residues
in
shellfish,
freshwater
finfish,
milk,
and
tissues
of
cattle,
sheep,
goats,
and
horses.
This
assessment
also
included
the
current
tolerances
on
field
corn
commodities.
For
this
Tier
1
analysis,
tolerance
values
were
used
for
fish
at
1.0
ppm;
shellfish
at
0.1
ppm;
kidney
of
cattle,
sheep,
goats,
and
horses
at
0.5
ppm;
other
meat
byproducts
of
cattle,
sheep,
goats,
and
horses
at
0.05
ppm;
meat
of
cattle,
sheep,
goats,
and
horses
0.05
ppm;
fat
of
cattle,
sheep,
goats,
and
horses
at
0.05
ppm;
and
milk
at
0.01
ppm.
Tolerance
level
residues
were
assumed,
including
those
for
field
corn
grain
(
0.05
ppm).
Chronic
dietary
exposure
analyses
for
the
overall
U.
S.
population
and
25
population
subgroups,
including
infants
and
children,
were
compared
to
the
chronic
Reference
Dose
(
RfD)
of
2.5
mg/
kg
b.
w./
day.
Results
of
the
chronic
dietary
analyses
for
all
population
subgroups
examined
were
less
than
0.1%
of
the
chronic
RfD.
Exposure
estimates
for
children
1
to
6
years
of
age,
the
most
highly
exposed
population
group,
were
only
0.000575
mg/
kg
b.
w./
day
or
less
than
0.1%
of
the
RfD.
Therefore,
the
results
of
the
chronic
dietary
assessment
demonstrate
a
reasonable
expectation
of
no
harm
from
the
proposed
and
existing
uses
of
imazapyr.
ii.
Drinking
water.
According
to
label
restrictions,
ARSENAL
herbicide
will
not
be
applied
directly
to
water
within
c
mile
upstream
of
an
active
potable
water
intake
in
flowing
water
(
i.
e.,
river,
stream,
etc.)
or
within
c
mile
of
an
active
potable
water
intake
in
a
standing
body
of
water
such
as
lake,
pond
or
reservoir.
However,
for
purposes
of
demonstrating
the
large
margin
of
exposure
to
imazapyr
residues
in
drinking
water,
no
label
restrictions
will
be
presumed.
Rather,
a
level
of
0.200
ppm
in
the
water
will
be
used,
as
based
upon
data
from
Missouri
and
Florida
sites
at
1
 
hour
after
treatment
(
maximum
levels
of
imazapyr
were
approximately
0.197
ppm
and
0.092
ppm,
respectively).
If
0.200
ppm
is
chosen
as
the
maximum
potential
residues
in
the
aquatic
dissipation
studies,
then
the
standard
(
chronic)
exposure
analyses
would
be:
Adult
male
(
200
µ
g/
L
x
10­
3
mg/
µ
g
X
2
L/
day)
/
70
kg
=
0.0057
mg/
kg/
day
Adult
female
(
200
µ
g/
L
x
10­
3
mg/
µ
g
X
2
L/
day)
/
60
kg
=
0.0067
mg/
kg/
day
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48366
Federal
Register
/
Vol.
68,
No.
156
/
Wednesday,
August
13,
2003
/
Notices
Children
(
200
µ
g/
L
x
10­
3
mg/
µ
g
X
1
L/
day)
/
10
kg
=
0.02
mg/
kg/
day
The
degree
of
risk
can
be
characterized
by
the
magnitude
of
the
margin
of
exposure
(
MOE),
which
is
the
ratio
of
the
NOAEL
from
the
animal
toxicity
study
used
to
set
the
RfD
to
an
estimated
human
exposure
value
(
MOE
=
NOAEL/
Human
Exposure).
Based
on
the
NOAEL
of
250
mg/
kg
b.
w./
day
from
the
chronic
dog
study
and
children's
exposure
value
(
worst
case)
of
0.02
mg/
kg
b.
w./
day,
a
very
high,
favorable
MOE
of
12,500
times
is
derived.
Thus,
there
is
a
reasonable
expectation
of
no
harm
from
the
proposed
and
existing
uses
of
imazapyr.
2.
Non­
dietary
exposure.
There
is
no
available
information
quantifying
nondietary
exposure
to
imazapyr.
However,
based
on
physical
and
chemical
characteristics
of
the
compound,
the
use
patterns,
and
available
information
concerning
its
environmental
fate,
nondietary
exposure
is
expected
to
be
negligible.
Previous
registrations
for
imazapyr
included
non­
crop
sites.
Labeled
use
sites
for
one
group
of
imazapyr
products
include
railroad,
utility,
pipeline,
and
highway
rights­
of­
way,
utility
plant
sites,
petroleum
tank
farms,
pumping
installations,
fence
rows,
storage
areas,
non­
irrigation
ditchbanks,
under
asphalt,
under
pond
liners,
wildlife
management
areas,
forestry
site
preparation,
and
other
non­
crop
areas.
Imazapyr
products
for
the
above
uses
are
clearly
not
intended
for
use
in
residential
or
recreational
areas
that
have
a
high
potential
of
exposure
for
the
general
population.
The
labels
state
that
these
imazapyr
products
are
not
for
use
on
lawns,
walks,
driveways,
tennis
courts
or
similar
areas.
Other
imazapyr
products
are
labeled
as
plant
growth
regulators
for
applications
to
limited
care­
low
maintenance
areas,
such
as
roadsides,
airports,
fairgrounds,
and
golf
course
roughs,
and
to
limited
wear
areas
such
as
industrial,
institutional,
and
cemetery
grounds.
These
low
rate
uses
entail
minimal
exposure
potential
for
the
general
population.
The
product
labeling
does
not
allow
use
on
turf
that
is
being
grown
for
sale
or
other
commercial
use,
such
as
sod.
There
are
imazapyr
products
marketed
for
residential
use.
These
total
vegetation
control
products
are
used
for
spot
treatments
or
bare
ground
applications.
These
products
are
to
be
applied
only
where
no
plant
growth
is
desired
and
are
not
to
be
used
on
lawns.
Therefore,
even
for
the
limited
residential
uses,
the
potential
for
exposure
is
minimal.
For
the
aquatic
use,
a
recreational
swimmer
risk
assessment
is
not
required
because
no
acute
toxicological
endpoints
for
oral,
dermal,
and
inhalation
routes
of
exposure
were
identified
by
EPA
for
imazapyr.
Moreover,
the
dermal
NOAEL
for
the
21
 
day
rabbit
toxicity
study
is
the
HDT
(
400
mg/
kg
b.
w./
day),
indicating
that
imazapyr
is
non­
toxic
following
repeated
dermal
exposure.
3.
Operator
exposure.
Specifically,
for
potential
short­
and
intermediate­
term
occupational
exposure,
professional
contractors
(
representing
worst­
case
for
the
proposed
uses)
would
be
mixing/
loading/
applying
the
end­
use
product
for
less
than
90
days
per
year
(
and
less
than
30
consecutive
days
per
year).
Importantly,
in
its
risk
characterization
of
imazapyr
for
use
in/
on
corn
(
1997),
EPA
found
no
toxicological
endpoints
indicating
potential
for
adverse
effects
that
were
identified
for
short­
term
(
1
 
7
days)
and
intermediate­
term
(
7
days
to
several
months)
occupational
exposure.
In
the
21
 
day
dermal
toxicity
study,
the
NOAEL
was
determined
to
be
400
mg/
kg
b.
w./
day
HDT.
This
was
further
supported
by
oral
NOAELs
of
250
mg/
kg
b.
w./
day
HDT
in
the
chronic
dog
study
and
500
mg/
kg
b.
w./
day
HDT
(
males)
or
640
mg/
kg
b.
w./
day
HDT
(
females)
in
the
chronic
rat
study.
Therefore,
short­
and
intermediate­
term
risk
assessments
are
not
required.

D.
Cumulative
Effects
Imazapyr
belongs
to
the
imidazolinone
class
of
compounds.
Other
compounds
in
this
class
are
registered
herbicides.
However,
the
herbicidal
activity
of
the
imidazolinones
is
due
to
the
inhibition
of
acetohydroxyacid
synthase
(
AHAS),
an
enzyme
only
found
in
plants.
AHAS
is
part
of
the
biosynthetic
pathway
leading
to
the
formation
of
branched
chain
amino
acids.
Animals
lack
AHAS
and
this
biosynthetic
pathway.
This
lack
of
AHAS
contributes
to
the
low
toxicity
of
the
imidazolinone
compounds
in
animals.
We
are
aware
of
no
information
to
indicate
or
suggest
that
imazapyr
has
any
toxic
effects
on
mammals
that
would
be
cumulative
with
those
of
any
other
chemical.

E.
Safety
Determination
1.
U.
S.
population.
Based
on
the
chronic
RfD
of
2.50
mg/
kg
b.
w./
day,
the
proposed
application
will
utilize
less
than
0.1%
of
this
value.
Exposure
estimates
for
the
general
U.
S.
population
were
only
0.000227
mg/
kg
b.
w./
day.
Exposure
estimates
for
children
1
to
6
years
of
age,
the
most
highly
exposed
population
group,
were
only
0.000575
mg/
kg
b.
w./
day
or
less
than
0.1%
of
the
RfD.
EPA
generally
has
no
concern
for
exposure
below
100%
of
the
RfD
which
represents
the
level
at
or
below
which
daily
aggregate
dietary
exposure
over
a
lifetime
will
not
pose
appreciable
risks
to
human
health.
The
complete
and
reliable
toxicity
data,
indicating
low
potential
mammalian
toxicity,
and
the
conservative
chronic
exposure
assumptions
support
the
conclusion
that
there
is
a
``
reasonable
certainty
of
no
harm''
from
aggregate
exposure
to
imazapyr
residues.
2.
Infants
and
children.
No
developmental,
reproductive
or
fetotoxic
effects
were
noted
at
the
highest
doses
of
imazapyr
tested.
The
only
maternal
effect
in
the
rat
teratology
study
was
increased
salivation
in
the
highest
dose
group.
The
NOAEL
used
to
calculate
the
RfD
for
the
general
U.
S.
population
is
250
mg/
kg
b.
w./
day
derived
from
the
1
 
year
chronic
toxicity
study
in
dogs.
That
NOAEL
is
lower
than
the
developmental
NOAELs
for
the
teratology
studies
in
rabbits
and
rats
(
1.6
and
4
times,
respectively),
as
well
as
lower
than
the
NOAEL
for
the
2
 
generation
reproduction
study
in
male
and
female
rats
(
3.2
­
3.9
times).
EPA
has
found
the
data
base
relative
to
prenatal
and
postnatal
effects
for
children
to
be
complete,
valid
and
reliable.
There
were
no
effects
observed
in
the
offspring
in
the
developmental
studies
in
rats
and
rabbits.
In
the
reproduction
study,
the
lack
of
any
pup
effects
observed
at
10,000
ppm
(
the
highest
dose
tested)
in
their
growth
and
development
from
parturition
through
adulthood,
suggests
that
there
is
no
additional
sensitivity
for
infants
and
children.
Therefore,
an
additional
safety
(
uncertainty)
factor
is
not
warranted
and
the
RfD
of
2.50
mg/
kg
b.
w./
day,
which
utilizes
a
100­
fold
safety
factor,
is
appropriate
to
assure
a
reasonable
certainty
of
no
harm
to
infants
and
children.
Therefore,
the
registrant
believes
that
the
results
of
the
toxicology
and
metabolism
studies
support
both
the
safety
of
imazapyr
to
humans
based
on
the
intended
use
as
a
herbicide
for
aquatic
and
grass
uses
and
the
granting
of
the
requested
tolerances.

F.
International
Tolerances
There
are
no
Codex
tolerances
established
for
imazapyr.

[
FR
Doc.
03
 
20640
Filed
8
 
12
 
03;
8:
45
am]

BILLING
CODE
6560
 
50
 
S
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