Document ID: EPA-HQ-OPP-2005-0535-0002
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-04-21T04:00Z

Interregional
Research
Project
Number
4
(
IR­
4)

3E6555,
4E6836,
5E6977,
5E6978
and
4F6895
Summary
of
Petitions
EPA
has
received
pesticide
petitions
(
3E6555,
4E6836,
5E6977,
5E6978
and
4F6895)
from
Interregional
Research
Project
Number
4
(
IR­
4),
Rutgers,
The
State
University
of
New
Jersey,
681
U.
S.
Highway
No.
1
South,
North
New
Brunswick,
NJ
08902
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
180.458
to
establish
tolerances
for
residues
of
of
the
herbicide
clethodim,
(
E)­(
±
)
­
2­[
1­[[(
3­
chloro­
2­
propenyl)
oxy]
imino]
propyl]­
5­[
2(
ethylthio)
propyl]
­
3­
hydroxy­
2
­
cyclohexen­
1­
one
and
its
metabolites
containing
the
2­
cyclohexene­
1­
one
moiety
in
or
on
the
raw
agricultural
commodities:
flax
seed
at
0.5
ppm
(
3E6555);
herb
subgroup
19A
at
10
ppm
(
4E6836);
asparagus
at
2.0
ppm
(
5E6977);
hops,
dry
cones,
at
0.5
ppm;
leafy
greens,
subgroup
4A,
including
cilantro
at
2.0
ppm
(
5E6978);
sesame
seed
at
0.4
ppm
(
4F6895);
vegetable,
legume,
group
6
at
3.0
ppm
(
4F6895);
and
safflower,
meal
at
10.0
ppm
and
safflower,
seed
at
5.0
ppm
(
4F6895).
The
petitioner,
IR­
4,
further
proposes,
upon
approval
of
the
aforementioned
tolerances,
to
remove
established
tolerances
for
residues
of
the
herbicide
clethodim
and
its
metabolites
containing
the
2­
cyclohexene­
1­
one
moiety
in
or
on
the
raw
agricultural
commodities
lettuce,
leaf,
beans,
dry,
and
spinach.

EPA
has
determined
that
the
petitions
contain
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.
This
notice
includes
a
summary
of
the
petition
prepared
by
Valent
U.
S.
A.
Corporation,
the
registrant,
Walnut
Creek,
CA
94596­
8025.

A.
Residue
Chemistry
1.
Plant
metabolism.
The
metabolism
of
clethodim
is
adequately
understood
for
the
purpose
of
the
proposed
tolerances.

2.
Analytical
method.

Practical
analytical
methods
for
detecting
and
measuring
levels
of
clethodim
and
its
metabolites
have
been
developed
and
validated
in/
on
all
appropriate
agricultural
commodities,
respective
processing
fractions,
milk,
animal
tissues,
and
environmental
samples.
The
methods
have
been
validated
at
independent
laboratories,
and
EPA
has
successfully
performed
an
analytical
method
trial.
For
most
commodities,
the
primary
enforcement
method
is
EPA­
RM­
26D­
3,
a
high
performance
liquid
chromatography
(
HPLC)
method
capable
of
distinguishing
clethodim
from
the
structurally
related
herbicide
sethoxydim.
3.
Magnitude
of
residues.
Residue
data
on
flax,
basil
(
fresh
and
dried),
chives
(
fresh
and
dried),
hops,
asparagus,
head
lettuce,
sesame,
snap
bean,
pea
(
dry),
lima
bean
(
succulent
shelled),
and
pea
(
succulent),
have
been
submitted
which
adequately
support
the
requested
tolerances.

B.
Toxicological
Profile
The
toxicological
profile
for
clethodim
which
supports
this
petition
for
tolerances
was
previously
published
in
the
Federal
Register
of
March
14,
2001
(
66
FR
14829)
(
FRL­
6770­
8).

C.
Aggregate
Exposure
1.
Dietary
exposure.
Chronic
dietary
analyses
were
conducted
to
estimate
exposure
to
potential
clethodim
residues
in/
on
the
following
crops:
peanuts,
cotton,
vegetable,
tuberous
and
corm
(
Group
1C),
vegetable,
brassica,
head
and
stem
(
Group
5A),
brassica,
leafy
greens
(
Group
5B),
vegetable,
fruiting
(
Group
8),
melon
(
Group
9A),
squash/
cucumber
(
Group
9B),
cranberry,
strawberry,
sunflower,
canola,
flax,
alfalfa,
mint,
and
clover
(
existing
tolerances);
vegetable,
root
and
tuber
(
Group
1),
vegetable,
leaves
of
root
and
tuber
(
Group
2),
vegetable,
bulb
(
Group
3),
berry
(
Group
13)(
tolerances
to
be
proposed
in
the
future);
and
herbs
(
Group
19A),
asparagus,
vegetable,
leafy
(
Group
4),
vegetable,
legume
(
Group
6),
hops,
safflower,
and
sesame
(
tolerances
proposed
in
the
current
petition).
The
Cumulative
and
Aggregate
Risk
Evaluation
System
(
CARES)
Version
1.1
was
used
to
conduct
this
assessment.
Actual
residue
data
and
conservative
estimates
for
percentages
of
the
crop
treated
were
used
in
these
assessments.
No
adjustments
were
made
for
common
washing,
cooking
or
preparation
practices.
Exposure
estimates
for
water
were
made
based
upon
modeling
(
GENEEC
and
SCI­
GROW).

i.
Food.
The
chronic
dietary
exposure
estimate
of
clethodim
residues
in
food
at
the
100th
percentile
was
calculated
to
be,
at
most,
24.2%
of
the
chronic
Population
Adjusted
Dose
(
c­
PAD)
with
a
Margin
of
Exposure
(
MOE)
of
410.
The
population
subgroup
with
the
highest
exposure
was
children
1­
2
years
old.
The
c­
PAD
was
defined
as
the
NOEL
from
a
dog
chronic
feeding
study
and
includes
an
uncertainty
factor
of
100
to
account
for
intra­
and
inter­
species
variation
(
NOEL
=
1.0
mg/
kg
bw/
day,
c­
PAD
=
0.01
mg/
kg/
day).

ii.
Drinking
water.
Since
clethodim
is
applied
outdoors
postemergence
to
growing
agricultural
crops,
the
potential
exists
for
clethodim
and/
or
its
metabolites
to
reach
ground
or
surface
water
that
may
be
used
for
drinking
water.
To
model
very
conservative
estimates
of
the
potential
concentrations
of
clethodim
and
its
sulfoxide
metabolite
in
drinking
water,
the
Agency
used
SCI­
GROW
for
groundwater,
and
Generic
Expected
Environmental
Concentration
(
GENEEC)
for
surface
water.
The
sum
of
the
parent
and
metabolite
estimated
concentrations
in
surface
water
greatly
exceeded
those
in
groundwater.
Based
on
the
GENEEC
and
SCI­
GROW
models,
the
estimated
environmental
concentrations
(
EECs)
of
clethodim
for
chronic
exposures
are
estimated
to
be
24.2
ppb
for
surface
water
and
0.49
ppb
for
ground
water
[
Federal
Register
of
March
14,
2001
(
66
FR
14829)
(
FRL­
6770­
8)].
Using
standard
assumptions
about
body
weight
and
water
consumption,
the
worse
case
chronic
exposure
from
drinking
water
would,
therefore,
be
0.0007
and
0.0024
mg/
kg
bw/
day
for
adults
and
children,
respectively;
24%
of
the
cPAD
for
children.
Based
on
this
worse
case
analysis,
the
contribution
of
water
to
the
chronic
dietary
risk
exceeds
food,
but
is
still
acceptable.

2.
Non­
dietary
exposure.
Clethodim
is
currently
registered
for
use
on
the
following
residential
non­
food
sites:
ornamental
plants,
wooden
containers
for
growing
plants,
golf
course
turf,
walkways,
trails,
and
paths.
There
are
no
indoor
uses
registered
for
clethodim.
Clethodim
kills
grassy
weeds
and
does
not
control
broadleaf
weeds.
Therefore,
clethodim
is
not
used
broadcast
on
turf,
but
only
on
edges
and
walkways,
thus
greatly
reducing
the
risk
of
residential
exposure.
The
Agency
did
calculate
that
these
potential
exposures
to
homeowner
applicators
and
other
potential
exposed
individuals
lead
to
acceptable
Margins
of
Exposure
(
MOE)
(
April
8,
1998,
63
FR
17101)(
FRL­
5784­
9).
However,
because
the
Agency
did
not
identify
short­
or
intermediate­
term
dermal
toxic
endpoints
of
concern,
these
risk
analyses
are
no
longer
necessary.

D.
Cumulative
Effects.
There
are
other
pesticidal
compounds
that
are
structurally
related
to
clethodim,
including
sethoxydim,
cycloxydim,
and
tralkoxydim.
Analytical
methods
convert
some
of
these
herbicides
and
their
metabolites
to
common
moieties.
Plant
and
animal
metabolism
data
demonstrate
that
no
common
metabolites
are
formed.
In
consideration
of
potential
cumulative
effects
of
clethodim
and
other
substances
that
may
have
a
common
mechanism
of
toxicity,
there
are
currently
no
available
data
or
other
reliable
information
indicating
that
any
toxic
effects
produced
by
clethodim
would
be
cumulative
with
those
of
other
chemical
compounds.
Thus,
only
the
potential
risks
of
clethodim
have
been
considered
in
this
assessment
of
aggregate
exposure
and
effects.

Valent
USA
Corporation
will
submit
information
for
EPA
to
consider
concerning
potential
cumulative
effects
of
clethodim
consistent
with
the
schedule
established
by
EPA
on
August
4,
1997
(
62
FR
42020)(
FRL­
5734­
6)
and
other
subsequent
EPA
publications
pursuant
to
the
Food
Quality
Protection
Act.

E.
Safety
Determination
1.
U.
S.
population­
chronic
exposure
and
risk
i.
Adult
sub­
populations.
Using
the
dietary
exposure
assessment
procedures
described
above
for
clethodim,
calculated
chronic
dietary
exposure
­­
taking
into
account
per
cent
of
crop
treated
and
using
actual
field
residues
­­
from
existing
and
proposed
uses
of
clethodim
is
minimal.
The
estimated
chronic
dietary
exposure
from
food
for
the
U.
S.
population
was
0.00047
mg/
kg
bw/
day,
4.7%
of
the
cPAD.
Addition
of
the
small
but
worse
case
potential
chronic
exposure
from
drinking
water
(
calculated
above)
increases
exposure
by
0.0007
mg/
kg
bw/
day
and
the
maximum
occupancy
of
the
cPAD
from
4.7%
to
11.7%.
Generally,
the
Agency
has
no
cause
for
concern
if
total
residue
contribution
is
less
than
100
percent
of
the
cPAD.
It
can
be
concluded
that
there
is
a
reasonable
certainty
that
no
harm
will
result
to
the
U.
S.
population
from
aggregate,
chronic
exposure
to
clethodim
residues.

ii.
Acute
dietary
exposure
and
risk
­­
Adult
sub­
populations.
An
acute
dietary
endpoint
was
not
identified.
Thus,
the
risk
from
acute
aggregate
dietary
exposure
to
clethodim
is
considered
to
be
negligible.
iii.
Non­
dietary
exposure
and
aggregate
risk
­­
Adult
sub­
populations.
Acute,
short
term,
and
intermediate
term
dermal
and
inhalation
risk
assessments
for
residential
exposure
to
clethodim
are
not
required
because
no
significant
toxicological
effects
were
observed.

2.
Infants
and
children
i.
Safety
factor
for
infants
and
children.
The
toxicological
data
base
for
evaluating
prenatal
and
postnatal
toxicity
for
clethodim
is
complete
with
respect
to
current
data
requirements.
There
are
no
special
prenatal
or
postnatal
toxicity
concerns
for
infants
and
children,
based
on
the
results
of
the
rat
and
rabbit
developmental
toxicity
studies
or
the
3­
generation
reproductive
toxicity
study
in
rats.
Valent
USA
Corporation
concludes
that
reliable
data
support
use
of
the
standard
100­
fold
uncertainty
factor
and
that
an
additional
uncertainty
factor
is
not
needed
for
clethodim
to
be
further
protective
of
infants
and
children.

ii.
Chronic
exposure
and
risk
­­
Infant
and
child
sub­
populations.
Using
the
conservative
exposure
assumptions
described
above
(
anticipated
residues
and
percent
of
crop
treated),
the
percentage
of
the
cPAD
that
will
be
utilized
by
dietary
(
food
only)
exposure
to
residues
of
clethodim
was
24.2%
for
children
,
1­
2
years
old.
Adding
the
worse
case
potential
incremental
exposure
to
infants
and
children
from
clethodim
in
drinking
water
(
0.0024
mg/
kg
bw/
day)
greatly
increases
the
aggregate,
chronic
dietary
exposure
and
the
occupancy
of
the
cPAD
by
24%
to
48.2%.
EPA
generally
has
no
concern
for
exposures
below
100%
of
the
cPAD
because
the
cPAD
represents
the
level
at
or
below
which
daily
aggregate
dietary
exposure
over
a
lifetime
will
not
pose
appreciable
risks
to
human
health.
It
can
be
concluded
that
there
is
a
reasonable
certainty
that
no
harm
will
result
to
infants
and
children
from
aggregate,
chronic
exposure
to
clethodim
residues.

iii.
Acute
dietary
exposure
and
risk
­­
Infant
and
child
sub­
populations.
An
acute
dietary
endpoint
was
not
identified.
Thus,
the
risk
from
acute
aggregate
dietary
exposure
to
clethodim
is
considered
to
be
negligible.

iv.
Non­
dietary
exposure
and
aggregate
risk
­­
Infant
and
child
sub­
populations.
Acute,
short
term,
and
intermediate
term
dermal
and
inhalation
risk
assessments
for
residential
exposure
to
clethodim
are
not
required
because
no
significant
toxicological
effects
were
observed.

F.
International
Tolerances
Codex,
Canadian,
or
Mexican
maximum
residue
levels
(
MRLs)
have
been
established
or
proposed
for
residues
of
clethodim
in/
on
sugar
beets
(
0.1
ppm),
potatoes
(
0.2
ppm),
rape
seed
(
0.5
ppm),
rape
seed
oils
(
0.5
ppm),
sunflower
seed
(
0.5
ppm),
and
sunflower
seed
oils
(
0.05
ppm).
There
are
no
conflicts
between
this
proposed
action
and
existing
international
residue
limits.