UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
April
16,
2002
MEMORANDUM:
LINURON:
IR­
4
Petitions
for
Use
on
Rhubarb
(8E5027)
and
Celeriac
(8E5028)
PC
Code
(035506)
DP
Barcodes
D281591
and
D281599
FROM:
Carol
Christensen,
Risk
Assessor
Reregistration
Branch
II
Health
Effects
Division
(7509C)

THRU:
Alan
Nielsen,
Branch
Senior
Scientist
Reregistration
Branch
II
Health
Effects
Division
(7509C)

TO:
Hoyt
Jamerson,
IR­
4
Petition
Manager
Minor
Use,
Inerts
and
Emergency
Response
Branch
Registration
Division
(7505C)

The
attached
document
was
generated
in
response
to
Inter­
Regional
Research
Project
number
4
IR4
petitions
for
the
establishment
of
tolerances
for
the
use
of
3­(
3,4­
dichlorophenyl)­
1­
methoxy­
1­
methylurea,
linuron,
on
rhubarb
(petition
8E5027)
and
celeriac
(petition
8E5028).
The
aggregate
exposures
and
risks
associated
with
the
use
of
linuron
were
assessed
in
the
HED
Chapter
of
the
Tolerance
Reassessment
Eligibility
Decision
document
dated
April
15,
2002
to
which
this
document
is
an
addendum.
Potential
risks
associated
with
the
additional
use
of
linuron
on
rhubarb
and
celeriac
are
represented
in
this
addendum.
The
dietary
exposures
were
assessed
by
John
Punzi
and
potential
occupational
exposures
were
assessed
by
Shanna
Recore.
Aggregate
risk
and
risk
characterization
were
discussed
by
Carol
Christensen.
The
aggregate
risk
from
linuron
(including
use
on
rhubarb
and
celeriac)
do
not
exceed
the
Agency's
level
of
concern.
2
IR­
4
Petitions:
Dietary
Exposure
to
Rhubarb
and
Celeriac
IR­
4
has
submitted
a
proposal
to
establish
a
tolerance
for
Linuron
in/
on
Rhubarb
(8E5027).
There
are
no
data
submitted
along
with
this
proposal.
The
request
is
for
field
trial
data
to
be
translated
from
celery
to
rhubarb.
The
proposed
label
directions
for
EPA
Reg.
No.
18112­
320
and
EPA
Reg.
No.
1812­
245
for
use
on
rhubarb
are
essentially
the
same
directions
as
for
celery.
The
following
use
parameters
are
proposed:
a
single
application
of
0.75
to
1.5
lbs
ai/
A
(not
to
exceed
2.0
lbs
ai/
A
(per
year));
application
as
a
non­
directed
broadcast
or
banded
spray
in
spring
or
late
summer
to
rhubarb
after
harvest
or
before
regrowth
of
the
crop;
and,
a
pre­
harvest
interval
(PHI)
of
30
days.
The
translation
of
data
and
use
directions
are
appropriate.
The
dietary
exposure
to
Linuron
from
the
addition
of
rhubarb
to
the
registered
uses
will
not
substantially
increase
the
exposure
to
Linuron
from
the
diet.
HED
recommends
that
a
tolerance
of
0.50
ppm
be
established
for
Linuron
and
metabolites
convertible
to
3,4­
DCA
in/
on
Rhubarb.

IR­
4
has
also
submitted
a
proposal
to
establish
a
tolerance
for
Linuron
in/
on
Celeriac
(8E5028).
There
are
no
data
submitted
along
with
this
proposal.
The
request
is
for
data
to
be
translated
from
carrot
to
celeriac.
The
proposed
label
use
directions
for
EPA
Reg.
No.
18112­
320
and
EPA
Reg.
No.
1812­
245
for
celeriac
are
essentially
the
same
directions
as
for
carrot.
The
following
use
parameters
are
proposed:
a
single
application
0.75
to
1.5
lbs
ai/
A
(not
to
exceed
2.0
lbs
ai/
A
(per
year)
and
application
as
a
non­
directed
spray
after
celeriac
is
transplanted
but
before
it
is
8
inches
high.
A
PHI
is
not
specified.
The
translation
of
data
and
use
directions
are
appropriate.
The
dietary
exposure
to
Linuron
from
the
addition
of
celeriac
to
the
registered
uses
will
not
substantially
increase
the
exposure
to
Linuron
from
the
diet.
HED
recommends
that
a
tolerance
of
1.0
ppm
be
established
for
Linuron
and
metabolites
convertible
to
3,4­
DCA
in/
on
celeriac.

Aggregate
Risk
Assessment
and
Risk
Characterization
Because
there
are
no
changes
to
the
dietary
exposure
and
risks
associated
with
the
use
of
linuron
when
rhubarb
and
celeriac
are
added
to
the
list
of
crops
on
which
the
chemical
may
be
used,
the
acute
and
chronic
aggregate
risk
assessments
prepared
in
the
HED
Chapter
of
the
Tolerance
Reassessment
Eligibility
Decision
document
dated
April
16,
2002
are
not
changed.
The
aggregate
risk
from
linuron
(including
use
on
rhubarb
and
celeriac)
do
not
exceed
the
Agency's
level
of
concern.

Occupational
Exposure
and
Risks
An
occupational
exposure
assessment
was
performed
for
the
use
of
linuron
on
rhubarb
and
celeriac.
(DP
Barcode
281845,
March
27,
2002)
The
herbicides
Linex
®
50DF
(dry
flowable)
and
Linex
®
4L
(liquid)
which
controls
grasses
and
broadleaf
weeds
were
included
in
the
assessment.
Linuron
may
be
applied
either
by
ground
sprayers
or
chemigation
to
rhubarb
and
celeriac.
A
maximum
of
one
application
of
1.5
lbs
active
ingredient
(ai)/
acre
per
season
is
proposed.
3
Based
on
the
proposed
use
patterns,
short­
term
dermal
and
inhalation
exposures
(1­
30
days)
are
expected
for
private
applicators
(farmers
treating
their
own
crops)
and
commercial
applicators.
Since
no
chemical­
specific
data
are
available
to
assess
potential
exposure
to
workers,
the
exposure
and
risk
assessment
presented
in
this
document
are
based
on
the
Pesticide
Handler
Exposure
Database
Version
1.1
(PHED,
Surrogate
Exposure
Guide,
August
1998).
The
maximum
application
rate
listed
on
the
label
was
used
for
all
calculations.
The
standard
values
for
acreage
were
taken
from
HED
Exposure
Science
Advisory
Committee
(Expo
SAC)
Policy
#
9.1,
effective
September
25,
2001.
All
calculated
Margins
of
Exposure
(MOEs)
do
not
exceed
HED's
level
of
concern.

Workers
having
potential
post­
application
re­
entry
exposure
to
linuron
from
the
proposed
use
include
scouts
and
workers
re­
entering
treated
fields
to
perform
irrigation
and
handweeding
tasks.
Since
linuron
will
be
applied
at
the
early
stages
of
crop
growth,
low
potential
for
post­
application
exposure
is
expected.
In
order
to
demonstrate
that
minimal
exposure
and
risk
are
expected,
a
post­
application
exposure
assessment
was
done
for
scouting,
handweeding
and
irrigating.
The
estimated
MOE
for
these
activities
related
to
the
proposed
use
of
linuron
on
rhubarb
and
celeriac
does
not
exceed
HED's
level
of
concern.

Reference:
Occupational
Exposure
and
Risk
Assessment/
Characterization
for
the
Proposed
Use
of
Linuron
on
Rhubarb
and
Celeriac.
S.
Recore,
March
27,
2002
DPBarcode
D281845.
