UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
May
31,
2002
CERTIFIED
MAIL
Ronald
Landis,
Ph.
D.
Landis
International
3185
Madison
Highway
PO
Box
5126
Valdosta,
GA
31603­
5126
Dear
Mr.
Landis:

This
is
the
Environmental
Protection
Agency's
(hereafter
referred
to
as
EPA
or
the
Agency)
"Report
of
the
Food
Quality
Protection
Act
(FQPA)
Tolerance
Reassessment
Progress
and
Risk
Management
Decision
(TRED)
for
Linuron",
which
was
approved
on
May
31,
2002.
A
Notice
of
Availability
of
this
tolerance
reassessment
decision
will
be
published
in
the
Federal
Register
(FR)
shortly.

The
Federal
Food,
Drug
and
Cosmetic
Act
(FFDCA),
as
amended
by
FQPA,
requires
EPA
to
reassess
all
the
tolerances
for
registered
chemicals
in
effect
on
or
before
the
date
of
the
enactment
of
the
FQPA,
which
was
in
August
of
1996.
In
reassessing
these
tolerances,
the
Agency
must
consider,
among
other
things,
aggregate
risks
from
non­
occupational
sources
of
pesticide
exposure,
whether
there
is
increased
susceptibility
to
infants
and
children,
and
the
cumulative
effects
of
pesticides
with
a
common
mechanism
of
toxicity.
Once
a
safety
finding
has
been
made
that
aggregate
risks
are
not
of
concern,
the
tolerances
are
considered
reassessed.
A
Reregistration
Eligibility
Decision
(RED)
for
linuron
was
completed
in
March,
1995,
prior
to
FQPA
enactment.
Therefore,
the
tolerances
need
to
be
reassessed
to
meet
the
FQPA
standard.

The
Agency
has
evaluated
the
dietary
risk
associated
with
linuron
and
has
determined
that
there
is
a
reasonable
certainty
that
no
harm
to
any
population
subgroup
will
result
from
aggregate
exposure
to
linuron
when
considering
dietary
exposure
and
all
other
non­
occupational
sources
of
pesticide
exposure
for
which
there
is
reliable
information.
However,
for
chronic
drinking
water
risk
from
surface
water,
potential
(average)
Estimated
Environmental
Concentrations
(EECs)
of
linuron
(18
ppb)
exceeds
the
chronic
Drinking
Water
Level
of
Comparison
(DWLOC)
(6
ppb)
for
infants
and
children,
the
most
sensitive
population
subgroups.
The
chronic
EECs
were
estimated
using
modeling
and
exceed
the
DWLOC
slightly.
The
EEC
estimate
is
based
on
upper­
end
input
parameters
such
as
an
assumption
that
87%
of
a
watershed
would
be
treated
with
linuron.
EECs
predicted
from
this
model
are
likely
higher
than
would
be
found
in
drinking
water
from
surface
reservoirs
because
it
is
unlikely
that
87%
of
a
watershed
would
be
treated
with
linuron.
Nonetheless,
additional
data
are
being
required
that
will
further
refine
the
chronic
drinking
water
risk
assessment.
A
leaching/
adsorption/
desorption
study
will
provide
data
on
the
mobility
of
linuron
and
a
terrestrial
field
dissipation
study
will
provide
information
on
what
happens
2
to
linuron
under
field
conditions.

FQPA
requires
that
EPA
consider
"available
information"
concerning
the
cumulative
effects
of
a
particular
pesticide's
residues
and
"other
substances
that
have
a
common
mechanism
of
toxicity."
The
reason
for
considering
other
substances
is
because
of
the
possibility
that
low­
level
exposures
to
multiple
chemical
substances
that
cause
a
common
toxic
effect
by
a
common
mechanism
could
lead
to
the
same
adverse
health
effect,
as
would
a
higher
level
of
exposure
to
any
of
the
other
substances
individually.
EPA
did
not
perform
a
cumulative
risk
assessment
as
part
of
this
review
of
linuron,
because
the
Agency
has
not
determined
that
there
are
any
other
chemical
substances
that
have
a
mechanism
of
toxicity
common
with
that
of
linuron.
If
EPA
identifies
other
substances
that
share
a
common
mechanism
of
toxicity
with
linuron,
then
a
cumulative
risk
assessment
will
be
conducted
that
includes
linuron
once
the
final
framework
EPA
will
use
for
conducting
cumulative
risk
assessments
is
available.
Further,
EPA
is
in
the
process
of
developing
criteria
for
characterizing
and
testing
endocrine
disrupting
chemicals
and
plans
to
implement
an
Endocrine
Disruptor
Screening
Program.
Linuron
will
be
reevaluated
at
that
time
and
additional
studies
may
be
requested.

The
Agency's
human
health
findings
for
the
pesticide
linuron,
were
discussed
in
a
closure
conference
call,
and
are
summarized
in
the
enclosed
Linuron
Overview
and
Linuron
Summary
of
the
risk
assessments.
The
risk
assessments
and
other
documents
pertaining
to
the
linuron
tolerance
reassessment
decision
are
available
on
the
Internet
at
http://
www.
epa.
gov/
pesticides/
reregistration/
status.
htm
and
are
in
the
public
docket
for
viewing.

The
Agency
has
reassessed
all
40
tolerances
for
linuron
and
can
make
a
FQPA
safety
determination.
In
addition,
three
new
tolerances
are
proposed
for
use
on
cotton
gin
by­
products
(9.0
ppm),
celeriac
(1.0
ppm),
and
rhubarb
(0.5
ppm).
The
Agency
has
sufficient
residue
data
for
reassessing
the
tolerances
for
linuron
and
is
requiring
additional
confirmatory
data
for
celery,
corn,
sorghum,
and
wheat.
Anticipated
residues
for
all
commodities
were
calculated
from
field
trial
data
and
subsequently
utilized
to
estimate
the
dietary
exposure
to
linuron.
For
commodities
that
require
additional
residue
data,
the
Current
Tolerance
value
was
used
in
the
acute
and
chronic
dietary
risk
assessments
and
this
is
the
value
that
will
continue
to
be
used
for
enforcement
purposes
until
the
additional
confirmatory
data
are
reviewed.
Acute
and
chronic
dietary
risks
from
exposure
do
not
exceed
the
Agency's
level
of
concern.
Final
tolerances
are
being
proposed
as
part
of
this
Tolerance
Reassessment
Decision.
Tolerances
may
be
revised
once
the
confirmatory
field
trial
data
have
been
submitted
to
and
reviewed
by
the
Agency.

Table
1.
Tolerance
Reassessment
Summary
for
Linuron.

Commodity
Current
Tolerance
(ppm)
1
Reassessed
Tolerance
Level
(ppm)
Comment/
Correct
Commodity
Definition
Tolerances
listed
under
40
CFR
§180.184(
a):

Asparagus
7.0
7.0
Carrots
1.0
1.0
[Carrot]

Cattle,
fat
1.0
0.2
Commodity
Current
Tolerance
(ppm)
1
Reassessed
Tolerance
Level
(ppm)
Comment/
Correct
Commodity
Definition
3
Cattle,
mbyp
1.0
0.1
[Cattle,
meat
byproducts,
except
kidney
and
liver]

Cattle,
meat
1.0
0.1
Celery
0.5
0.5
/
(TBD
4)
The
available
data
support
use
east
of
the
Rocky
Mountains;
additional
data
are
required
to
support
use
on
celery
west
of
the
Rocky
Mountains.

Corn,
field,
fodder
1.0
6.0
[Corn,
field,
stover]

Corn,
field,
forage
1.0
1.0
Corn,
fresh
(inc.
sweet
K+
CWHR)
0.25
0.25
/
(TBD
4)
Additional
crop
field
trial
data
are
required.
[Corn,
sweet
(K+
CWHR)]

Corn,
grain
(inc.
popcorn)
0.25
0.1
Popcorn
grain
tolerance
should
be
deleted
since
there
are
no
registered
uses.
[Corn,
field,
grain]

Corn,
sweet,
fodder
1.0
1.0
/
(TBD
4)
Additional
crop
field
trial
data
are
required.
[Corn,
sweet,
stover]

Corn,
sweet,
forage
1.0
1.0
/
(TBD
4
)
Additional
crop
field
trial
data
are
required.

Cottonseed
0.25
Reassign
This
tolerance
should
be
reclassified
under
180.184(
c)
because
use
of
linuron
on
cotton
is
restricted
to
east
of
the
Rocky
Mountains.

Goats,
fat
1.0
0.2
[Goat,
fat]

Goats,
mbyp
1.0
0.1
[Goat,
meat
byproducts,
except
kidney
and
liver]

Goats,
meat
1.0
0.1
[Goat,
meat]

Hogs,
fat
1.0
0.05
[Hog,
fat]

Hogs,
mbyp
1.0
0.1
[Hog,
meat
byproducts]

Hogs,
meat
1.0
0.05
[Hog,
meat]

Horses,
fat
1.0
0.2
[Horse,
fat]
Commodity
Current
Tolerance
(ppm)
1
Reassessed
Tolerance
Level
(ppm)
Comment/
Correct
Commodity
Definition
4
Horses,
mbyp
1.0
0.1
[Horse,
meat
byproducts,
except
kidney
and
liver]

Horses,
meat
1.0
0.1
[Horse,
meat]

Parsnips
(with
tops)
0.5
0.05
[Parsnip,
root]

Parsnips
(without
tops)
0.5
0.05
[Parsnip,
root]

Potatoes
1.0
Reassign
This
tolerance
should
be
reclassified
under
180.184(
c)
as
use
of
linuron
on
potatoes
is
restricted
to
east
of
the
Rocky
Mountains.

Sheep,
fat
1.0
0.2
Sheep,
mbyp
1.0
0.1
[Sheep,
meat
byproducts,
except
kidney
and
liver]

Sheep,
meat
1.0
0.1
Sorghum,
fodder
1.0
1.0
/
(TBD
4)
Additional
crop
field
trial
data
are
required.
[Sorghum,
stover]

Sorghum,
forage
1.0
1.0
/
(TBD
4)
Additional
crop
field
trial
data
are
required.

Sorghum,
grain
(milo)
0.25
0.25
[Sorghum,
grain]

Soybeans
(dry)
1.0
1.0
[Soybean,
seed]

Soybeans
(succulent)
1.0
1.0
[Soybean,
seed]

Soybean,
forage
1.0
Revoke
These
tolerances
should
be
revoked,
provided
all
pertinent
labels
are
amended
to
include
the
following
feeding
restriction
on
the
product
labels:
"The
feeding
of
treated
forage
or
hay
to
livestock
is
prohibited.

Soybean,
hay
1.0
Revoke
Commodity
Current
Tolerance
(ppm)
1
Reassessed
Tolerance
Level
(ppm)
Comment/
Correct
Commodity
Definition
5
Wheat,
forage
0.5
Reassign
These
tolerances
should
be
reclassified
under
180.184(
c),
as
use
of
linuron
on
wheat
is
restricted
to
ID,
OR,
and
WA.
Wheat,
grain
0.25
Reassign
Wheat,
hay
0.5
Reassign
Wheat,
straw
0.5
Reassign
Tolerances
listed
under
40
CFR
§180.184(
c):

Parsley
0.25
0.25
Tolerances
established
under
40
CFR
§180.184(
a):

Cattle,
kidney
Not
applicable
2.0
Cattle,
liver
Not
applicable
2.0
Celeraic
Not
applicable
1.0
Goat,
kidney
Not
applicable
2.0
Goat,
liver
Not
applicable
2.0
Horse,
kidney
Not
applicable
2.0
Horse,
liver
Not
applicable
2.0
Milk
Not
applicable
0.05
Rhubarb
Not
applicable
0.5
Sheep,
kidney
Not
applicable
2.0
Sheep,
liver
Not
applicable
2.0
Tolerances
established
under
40
CFR
§180.184(
c):

Cotton,
gin
byproducts
Not
applicable
9.0
Additional
field
trial
data
and/
or
information
is
required.

Cottonseed
0.25
0.05
This
tolerance
should
be
reclassified
under
180.184(
c)
because
use
of
linuron
on
cotton
is
restricted
to
east
of
the
Rocky
Mountains.
[Cotton,
undelinted
seed]

Potatoes
1.0
0.2
This
tolerance
should
be
reclassified
under
180.184(
c)
because
use
of
linuron
on
potatoes
is
restricted
to
east
of
the
Rocky
Mountains.
[Potato]
Commodity
Current
Tolerance
(ppm)
1
Reassessed
Tolerance
Level
(ppm)
Comment/
Correct
Commodity
Definition
6
Wheat,
forage
0.5
0.5
/
(TBD
4)
Crop
field
trial
data
are
required.
This
tolerance
should
be
reclassified
under
180.184(
c),
because
use
of
linuron
on
wheat
is
restricted
to
ID,
OR,
and
WA.

Wheat,
grain
0.25
0.05
This
tolerance
should
be
reclassified
under
180.184(
c),
because
use
of
linuron
on
wheat
is
restricted
to
ID,
OR,
and
WA.

Wheat,
hay
0.5
0.5
/
(TBD
4)
Crop
field
trial
data
are
required.
This
tolerance
should
be
reclassified
under
180.184(
c),
because
use
of
linuron
on
wheat
is
restricted
to
ID,
OR,
and
WA.

Wheat,
straw
0.5
2.0
The
registrants
may
wish
to
generate
additional
crop
field
trial
data
at
1x
instead
of
proposing
an
increased
tolerance.
This
tolerance
should
be
reclassified
under
180.184(
c),
because
use
of
linuron
on
wheat
is
restricted
to
ID,
OR,
and
WA.

1
Expressed
in
terms
of
linuron
per
se.
2
Refer
to
sections
on
Magnitude
of
the
Residue
in
Crop
Plants,
Magnitude
of
the
Residue
in
Processed
Food/
Feed,
and
Magnitude
of
the
Residue
in
Meat,
Milk,
Poultry,
and
Eggs
for
detailed
discussion
of
residues
in
plant
and
animal
commodities.
3
Expected
residues
at
a
1x
feeding
level.
4
These
commodities
were
included
in
the
dietary
risk
assessment
using
the
Current
Tolerance
level.
Additional
confirmatory
field
trial
residue
data
are
required;
therefore,
the
final
tolerance
may
be
revised.

No
maximum
residue
limits
(MRLs)
for
linuron
have
been
established
by
Codex
for
any
agricultural
commodity.
In
addition,
no
Canadian
nor
Mexican
MRLs
have
been
established
for
linuron.
Therefore,
no
compatibility
questions
exist
with
respect
to
U.
S.
tolerances.

Note
that
you
will
be
sent
a
Section
3(
c)(
2)(
B)
Data­
Call­
In
(DCI)
letter
under
the
Federal
Insecticide,
Fungicide,
Rodenticide
Act
(FIFRA)
in
a
separate
mailing.
If
you
have
questions
on
this
document,
please
contact
the
Chemical
Review
Manager,
Dirk
V.
Helder,
at
(703)
305­
4610.

Sincerely,

Lois
A.
Rossi,
Director
Special
Review
and
Reregistration
Division
7
Enclosures:
"Linuron
Overview"
and
"Linuron
Summary"
