
1
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES,
AND
TOXIC
SUBSTANCES
March
27,
2002
MEMORANDUM
SUBJECT:
Occupational
Exposure
and
Risk
Assessment/
Characterization
for
the
Proposed
Use
of
Linuron
on
Rhubarb
and
Celeriac.

FROM:
Shanna
Recore,
Industrial
Hygienist
Reregistration
Branch
II
Health
Effects
Division
(7509C)

TO:
Carol
Christensen,
Risk
Assessor
Reregistration
Branch
II
Health
Effects
Division
(7509C)

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

Please
find
the
review
of
Linuron.

DP
Barcode:
D281845
Pesticide
Chemical
Codes:
035506
EPA
Reg
Numbers:
1812­
245,
1812­
320
PHED:
Yes,
Version
1.1
Summary
2
Interregional
Research
Project
No.
4
(IR­
4),
on
behalf
of
Griffin
Corporation,
is
proposing
two
new
uses,
rhubarb
and
celeriac,
for
the
herbicides
Linex
®
50DF
(dry
flowable)
and
Linex
®
4L
(liquid)
which
controls
grasses
and
broadleaf
weeds.
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.

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
at
the
minimum
personal
protective
equipment
(PPE)
level.

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,
on
the
day
of
application.

Use
Patterns
and
Formulations
IR­
4,
on
behalf
of
Griffin
LLC,
has
proposed
the
registration
of
two
new
uses,
rhubarb
and
celeriac,
for
the
previously
registered
herbicides
Linex
®
50DF
(EPA
Reg.
No.
1812­
320)
and
Linex
®
4L
(EPA
Reg.
No.
1812­
245).
Linex
®
50DF
is
a
dry
flowable
containing
50%
of
the
ai
linuron.
Linex
®
4L
is
a
liquid
containing
40.6%
of
the
ai
linuron.
According
to
the
labels,
this
product
is
applied
as
a
non­
direct
spray
to
control
annual
grasses
and
broadleaf
weeds.
A
maximum
of
one
to
two
application
per
season
of
0.75
to
1.5
lbs
ai/
acre,
but
no
more
than
2
lb
ai/
acre/
year,
may
be
applied
by
ground
sprayers
or
by
chemigation
(Linex
®
4L
only).
For
Linex
®
50DF,
applications
using
irrigation
equipment
is
prohibited.
According
to
the
proposed
labels,
linuron
is
applied
to
rhubarb,
after
harvest
but
before
the
regrowth
of
crop,
and
to
celeriac,
before
a
height
of
eight
inches
is
reached
and
before
annual
grasses
exceed
two
inches
in
height
and
before
broadleaf
weed
exceed
six
inches
in
height.
Table
1
summarizes
the
proposed
linuron
use
on
rhubarb
and
celeriac.
Currently,
there
are
no
registered
or
proposed
residential
uses
of
linuron.
4,5
Table
1:
Use
Pattern
Summary
of
Linuron
on
Rhubarb
and
Celeriac
3
Formulation
Linex
®
50DF
­
dry
flowable
Linex
®
4L
­
liquid
Pests
annual
grasses
and
broadleaf
weeds
Application
methods
Linex
®
50DF
­
groundboom
sprayer
Linex
®
4L
­
groundboom
sprayer
and
chemigation
Maximum
application
rate
(AR)
1.5
lbs
a.
i./
acre
(Maximum
application
per
year
is
2
lbs
ai/
acre)

Number
of
applications
per
season
1­
2
Timing/
frequency
Rhubarb
­
after
harvest
but
before
the
regrowth
of
crop
Celeriac
­
before
a
height
of
8
inches
is
reached
and
before
annual
grasses
exceed
2
inches
in
height
and
before
broadleaf
weed
exceed
6
inches
in
height
Manufacturer
Griffin
LLC
Toxicological
Profile
Table
2
presents
the
acute
toxicity
categories
as
outlined
in
the
Linuron
­
Report
of
the
Hazard
Identification
Assessment
Review
Committee
(HIARC).
3
Table
2:
Acute
Toxicity
of
Linuron
(ai)

Guideline
No.
Study
Type
MRIDs
#
Results
Toxicity
Category
870.110
Acute
Oral
(Rat)
00027625
LD50
=
2600
mg/
kg
III
870.1200
Acute
Dermal
(Rabbit)
00027625
LD50
>
2,000
mg/
kg
III
870.1300
Acute
Inhalation
(Rat)
00053769
LC50
>
218
mg/
L
IV
870.2400
Primary
Eye
Irritation
42849001
Slight
conjunctival
redness
at
24
hrs;
clear
at
72
hrs
III
870.2500
Primary
Skin
Irritation
42849002
Not
an
irritant
IV
870.2600
Dermal
Sensitization
00146868
Not
a
sensitizer
N/
A
The
HIARC
memorandum,
dated
November
20,
2001,
indicates
that
there
are
toxicological
endpoints
of
concern
for
linuron.
The
endpoints,
and
associated
uncertainty
factors
used
in
assessing
the
risks
for
linuron
are
presented
in
Table
3.
3
Table
3:
Summary
of
Dose
and
Toxicological
Endpoints
for
Linuron
4
Exposure
Scenario
NOAEL
(mg/
kg/
day)
Effect
Study
Uncertainty
Factors
Target
MOE
Short­
Term
Dermal
(1­
30
days)

(Occupational/
Residential)
Oral
NOAEL
=
5.8
a
Statistically
and
biologically
significant
decrease
in
premating
body
weights
in
F0
and
F1
animals
2­
Generation
Reproduction
Study
­
Rat
Interspecies:
10x
Intraspecies:
10x
FQPA:
10x
Occupational:
100
IntermediateTerm
Dermal
(1
­
6
months)

(Occupational/
Residential)
Oral
NOAEL
=
0.77
a
Increased
met­
and
sulfhemoglobin
levels
after
3
and
6
months
of
treatment
Chronic
Feeding
Study
­
Dog
Interspecies:
10x
Intraspecies:
10x
FQPA:
10x
Occupational:
100
Long­
Term
Dermal
(Longer
than
6
months)
(Occupational/
Residential)
Oral
NOAEL
=
0.77
a
Increased
met­
and
sulfhemoglobin
levels
Chronic
Feeding
Study
­
Dog
Interspecies:
10x
Intraspecies:
10x
FQPA:
10x
Occupational:
100
Short­
Term
Inhalation
(1­
30
days)

(Occupational/
Residential)
Oral
NOAEL
=
5.8
b
statistically
and
biologically
significant
decrease
in
premating
body
weights
in
F0
and
F1
animals
2­
Generation
Reproduction
Study
­
Rat
Interspecies:
10x
Intraspecies:
10x
FQPA:
10x
Occupational:
100
IntermediateTerm
Inhalation
(1
to
6
months)

(Occupational/
Residential)
Oral
NOAEL
=
0.77
b
Increased
met­
and
sulfhemoglobin
levels
Chronic
Feeding
Study
­
Dog
Interspecies:
10x
Intraspecies:
10x
FQPA:
10x
Occupational:
100
Long­
Term
Inhalation
(Longer
than
6
months)

(Occupational/
Residential)
Oral
NOAEL=
0.77
b
Increased
met­
and
sulfhemoglobin
levels
Chronic
Feeding
Study
­
Dog
Interspecies:
10x
Intraspecies:
10x
FQPA:
10x
Occupational:
100
Footnote
a
=
Assume
16%
dermal
absorption
for
route­
to­
route
extrapolation
b
=
Assume
100%
inhalation
absorption
for
route­
to­
route
extrapolation
FQPA
Safety
Factor
The
FQPA
Safety
Factor
Committee
memorandum,
dated
December
6,
2001,
5
recommended
that
the
FQPA
safety
factor
be
retained
at
10x
for
the
following
weight­
ofevidence
considerations:

°
a
qualitative
increase
in
susceptibility
seen
in
the
F1
males
in
the
rat
reproductive
toxicity
study;
and
°
a
developmental
neurotoxicity
study
in
rats
is
required
for
the
chemical
because
linuron
is
a
potential
endocrine
disruptor
and
there
is
evidence
for
testicular
lesions
and
decreased
fertility
in
the
rat
reproductive
toxicity
study.

However,
the
Committee
concluded
that
the
safety
factor
could
be
reduced
to
3x
for
linuron
because:

°
the
toxicology
database
is
complete;
°
the
dietary
(food
and
water)
exposure
assessments
will
not
underestimate
the
potential
exposures
for
infants,
children,
and/
or
women
of
childbearing
age;
and
°
there
are
no
residential
uses.

When
assessing
acute
dietary
exposure
of
females
13­
50
years
of
age,
the
safety
factor
should
be
reduced
to
3x
since
the
developmental
neurotoxicity
study
in
rats
is
required
and
may
further
define
the
neurotoxic
(neuro­
endocrine)
potential
observed
in
rats
that
were
exposed
in
pre­
and
post­
natal
time
periods.
However,
when
assessing
chronic
dietary
exposure
to
all
other
population
sub­
groups,
the
safety
factor
should
be
retained
at
10x
since
there
is
concern
for
the
qualitative
increase
in
susceptibility
observed
in
the
rat
reproductive
toxicity
study
(a
long­
term
study),
and,
since
the
developmental
neurotoxicity
study
in
rats
is
required.
The
developmental
neurotoxicity
study
may
further
define
the
neurotoxic
(neuro­
endocrine)
potential
observed
in
rats
due
to
pre­
and
post­
natal
exposure.
2
Cancer
Determination
The
RfD/
Peer
Review
Committee
has
classified
linuron
as
an
unquantifiable
Group
C
carcinogen
(a
possible
human
carcinogen
for
which
there
is
limited
animal
evidence)
requiring
no
quantification
of
human
cancer
risk.

Occupation
Exposure
Assessment
Occupational
Handler
Exposures
and
Risk
Estimates
PHED
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
Handlers
Exposure
Database
(PHED)
Version
1.1.
It
is
the
policy
of
the
HED
to
use
data
from
PHED
to
assess
handler
exposures
for
regulatory
actions
when
chemical­
specific
monitoring
data
are
not
available.
7
6
PHED
was
designed
by
a
task
force
of
representatives
from
the
U.
S.
EPA,
Health
Canada,
the
California
Department
of
Pesticide
regulation,
and
member
companies
of
the
American
Crop
Protection
Association.
PHED
is
a
software
system
consisting
of
two
parts
­­
a
database
of
measured
exposure
values
for
workers
involved
in
the
handling
of
pesticides
under
actual
field
conditions
and
a
set
of
computer
algorithms
used
to
subset
and
statistically
summarize
the
selected
data.
Currently,
the
database
contains
values
for
over
1,700
monitored
individuals
(i.
e.,
replicates).

Users
select
criteria
to
subset
the
PHED
database
to
reflect
the
exposure
scenario
being
evaluated.
The
subsetting
algorithms
in
PHED
are
based
on
the
central
assumption
that
the
magnitude
of
handler
exposures
to
pesticides
are
primarily
a
function
of
activity
(e.
g.,
mixing/
loading,
applying),
formulation
type
(e.
g.,
wettable
powders,
granulars),
application
method
(e.
g.,
aerial,
groundboom),
and
clothing
scenarios
(e.
g.,
gloves,
double
layer
clothing).

Once
the
data
for
a
given
exposure
scenario
have
been
selected,
the
data
are
normalized
(i.
e.,
divided
by)
by
the
amount
of
pesticide
handled
resulting
in
standard
unit
exposures
(milligrams
of
exposure
per
pound
of
active
ingredient
handled).
Following
normalization,
the
data
are
statistically
summarized.
The
distribution
of
exposure
values
for
each
body
part
(e.
g.,
chest
upper
arm)
is
categorized
as
normal,
lognormal,
or
"other"
(i.
e.,
neither
normal
nor
lognormal).
A
central
tendency
value
is
then
selected
from
the
distribution
of
the
exposure
values
for
each
body
part.
These
values
are
the
arithmetic
mean
for
normal
distributions,
the
geometric
mean
for
lognormal
distributions,
and
the
median
for
all
"other"
distributions.
Once
selected,
the
central
tendency
values
for
each
body
part
are
composited
into
a
"best
fit"
exposure
value
representing
the
entire
body.

The
unit
exposure
values
calculated
by
PHED
generally
range
from
the
geometric
mean
to
the
median
of
the
selected
data
set.
To
add
consistency
and
quality
control
to
the
values
produced
from
this
system,
the
PHED
Task
Force
has
evaluated
all
data
within
the
system
and
has
developed
a
set
of
grading
criteria
to
characterize
the
quality
of
the
original
study
data.
The
assessment
of
data
quality
is
based
on
the
number
of
observations
and
the
available
quality
control
data.
These
evaluation
criteria
and
the
caveats
specific
to
each
exposure
scenario
are
summarized
in
Table
6.
While
data
from
PHED
provide
the
best
available
information
on
handler
exposures,
it
should
be
noted
that
some
aspects
of
the
included
studies
(e.
g.,
duration,
acres
treated,
pounds
of
active
ingredient
handled)
may
not
accurately
represent
labeled
uses
in
all
cases.
HED
has
developed
a
series
of
tables
of
standard
unit
exposure
values
for
many
occupational
scenarios
that
can
be
utilized
to
ensure
consistency
in
exposure
assessments.
6
7
Occupational
Handler
Exposure
Scenarios
HED
has
determined
that
there
are
potential
exposures
to
mixer,
loader,
applicator
and
other
handlers
during
the
usual
use­
patterns
associated
with
linuron.
Based
on
the
use
patterns,
three
major
occupational
exposure
scenarios
were
identified
for
linuron:

(1a)
mixing/
loading
liquids
for
ground
application;
(1b)
mixing/
loading
liquids
for
chemigation
application;
(2)
mixing/
loading
dry
flowable
for
ground
application;
and
(3)
applying
liquids
with
groundboom
sprayer.

The
current
Linex
®
50DF
and
Linex
®
4L
labels
have
the
following
PPE
requirements
for
handlers:
coveralls
over
short­
sleeved
shirt
and
short
pants,
waterproof
gloves,
shoes
plus
socks,
and
chemical­
resistant
headgear
for
overhead
exposures.

Assumptions
for
Handler
Exposure
Scenarios
The
following
assumptions
and
factors
were
used
in
order
to
complete
this
exposure
assessment:

C
average
body
weight
of
an
adult
handler
is
70
kg;

°
average
work
day
interval
represents
an
8
hour
workday
(e.
g.,
the
acres
treated
or
volume
of
spray
solution
prepared
in
a
typical
day);

°
for
groundboom
equipment
use
on
rhubarb
and
celeriac,
80
acres
per
day
was
used
to
assess
handler
exposure;
8
°
for
chemigation
application
to
rhubarb
and
celeriac,
350
acres
per
day
was
used;
8
°
aerial
application
will
be
prohibited
on
the
label
for
application
to
rhubarb
and
celeriac;

°
calculations
are
completed
at
the
maximum
application
rates
for
crops
as
stated
on
the
designated
linuron
labels;
and
°
due
to
a
lack
of
scenario­
specific
data,
HED
calculates
unit
exposure
values
using
generic
protection
factors
that
are
applied
to
represent
various
risk
mitigation
options
(i.
e.,
the
use
of
PPE
and
engineering
controls).
8
Occupational
Handler
Exposures
and
Non­
Cancer
Risk
Assessment
Equations
to
Calculate
Handler
Exposure
Daily
dermal
exposure
is
calculated
using
the
following
formula:

Daily
inhalation
exposure
is
calculated
using
the
following
formula:

The
daily
dermal
and
inhalation
dose
is
calculated
as
follows
using
a
70
kg
body
weight:

The
dermal
and
inhalation
MOEs
were
calculated
using
the
following
formulas:

Based
on
the
available
toxicity
data,
it
is
appropriate
to
combine
short­
term
dermal
and
inhalation
MOEs
because
the
effects
observed
at
the
LOAEL
were
identical.
The
total
MOE
9
were
calculated
using
the
following
formula:

Based
on
the
proposed
use
patterns,
short­
term
(1
to
30
days)
dermal
and
inhalation
exposures
are
expected
for
private
applicators
(farmers
treating
their
own
crops)
and
commercial
applicators.
Since
linuron
may
be
applied
only
one
to
two
times
per
year
and
has
a
limited
crop
production
(for
celeriac
­
only
750
acres
are
grown
in
the
United
States;
for
rhubarb
­
only
860
acres
are
grown
in
the
United
States),
intermediate­
term
(30
days
to
6
months)
and
long­
term
(longer
than
6
months)
exposures
are
not
expected
from
the
proposed
use.
Table
4
presents
the
summary
of
occupational
handler
short­
term
(1­
30
days)
dermal
and
inhalation
exposures
at
baseline,
with
additional
personal
protective
equipment,
and
with
engineering
controls.
Table
5
lists
the
caveats
and
parameters
specific
to
the
surrogate
data
used
for
each
scenario
and
corresponding
exposure/
risk
assessment.
See
appendix
tables
A,
B,
C,
and
D
for
additional
information.
10
Table
4.
Summary
of
Occupational
Handler
Short­
term
Dermal
and
Inhalation
Total
Exposure
Variables
Exposure
Scenario
(Scenario
#)
Crop
Application
rates
a
Area
Treated
Total
Short­
term
MOE
Baseline
b,
f
Total
Short
term
MOE
Min
PPE
c,
f
Total
Short
term
MOE
Max
PPE
d,
f
Total
Short
term
MOE
Eng.
Control
e,
f
Mixer/
Loader
Mixing/
Loading
Liquids
for
Groundboom
application
(1a)
Rhubarb
and
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
7.
3
860
­


Mixing/
Loading
Liquids
for
Chemigation
application
(1b)
Rhubarb
and
Celeriac
1.50
lb
ai
per
acre
350
Acres
per
day
1.
7
200
­


Dry
Flowables
for
Groundboom
application
(2)
Rhubarb
and
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
300
­
­


Applicator
Sprays
for
Groundboom
application
(3)
Rhubarb
and
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
1100
­
­


Footnotes
:

a
Application
Rates
are
based
on
the
maximum
application
rates
listed
on
the
proposed
linuron
labels.

b
Baseline
dermal
unit
exposure
represents
long
pants,
long
sleeved
shirt,
no
gloves,
open
mixing/
loading,
open
cab
tractor
and
baseline
inhalation
unit
exposure
represents
no
respirator
8
.

c
Minimum
PPE
for
all
dermal
scenarios
include
chemical
resistant
gloves
(90%
Protection
Factor)
and
minimum
PPE
for
all
inhalation
scenarios
include
a
dust/
mist
respirator
(5­
fold
Protection
Factor).

d
Maximum
PPE
for
all
dermal
scenarios
include
double
layer
of
clothing
(50%
Protection
Factor
for
clothing)
and
chemical
resistant
gloves
(90%
Protection
Factor)
and
maximum
PPE
for
all
inhalation
scenarios
include
an
organic
vapor
respirator
(90%
Protection
Factor).

e
Engineering
Controls
for
mixer/
loader
include
closed
mixing/
loading,
single
layer
clothing
and
scenario
1a
and
1b
also
include
chemical
resistant
gloves.
Engineering
Controls
for
applicators
and
flaggers
include
enclosed
cockpit,
cab
or
truck,
single
layer
clothing,
no
gloves.

f
Total
MOE
(combined
dermal
and
inhalation)
=
1
/
((
1/
dermal
MOE)
+
(1/
inhalation
MOE))

­
Scenario's
calculated
MOE
exceeds
the
target
MOE
at
the
previous
level
of
mitigation
(MOE>
100)

Table
5.
Occupational
Handler
Exposure
Scenario
Descriptions
for
the
Use
of
Linuron
11
Exposure
Scenario
(Scenario
Number)
Data
Source
Standard
Assumption
a
(8­
hr
work
day)
Comments
b
MIXER/
LOADER
DESCRIPTORS
Mixing/
Loading
Liquid
Formulations
(1a,
b)
PHED
V1.1
°
80
acres
for
groundboom
to
rhubarb
and
celeriac
°
350
acres
for
chemigation
application
to
rhubarb
and
celeriac
Baseline:
Hand,
dermal,
and
inhalation
data
are
AB
grades.
Hand
=
72
to
122
replicates;
dermal
=
53
replicates;

and
inhalation
=
85
replicates.
High
confidence
in
hand/
dermal
and
inhalation
data.
No
protection
factor
was
needed
to
define
the
unit
exposure
value.

PPE:
The
same
dermal
and
inhalation
data
are
used
as
for
the
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing,
and
an
80%
protection
factor
to
account
for
the
use
of
a
dust/
mist
respirator
and
90%
protection
factor
to
account
for
the
use
of
an
organic
vapor
respirator,
respectively.
Hand
data
are
AB
grades,
with
59
replicates.
High
confidence
in
hand/
dermal
data.

Engineering
Controls:
Hand,
dermal,
and
inhalation
data
are
AB
grades.
Hand
=
31
replicates;
dermal
=16
to
22
replicates;
inhalation
=
27
replicates.
High
confidence
in
hand/
dermal
and
inhalation
data.

Mixing/
Loading
Dry
Flowable
Formulations
(2)
PHED
V1.1
°
80
acres
for
groundboom
to
rhubarb
and
celeriac
Baseline:
Hand,
dermal
and
inhalation
data
are
AB
grades.
Hand
=
7
replicates;
dermal
=
16
to
26
replicates;
and
inhalation
=
23
replicates.
Low
confidence
in
hand/
dermal
data
and
high
confidence
in
inhalation
data.

PPE:
Hand/
dermal
data
are
AB
grades.
The
same
inhalation
data
are
used
as
for
the
baseline
coupled
with
an
80%

protection
factor
to
account
for
the
use
of
a
dust/
mist
respirator
and
90%
protection
factor
to
account
for
the
use
of
an
organic
vapor
respirator.
Hand
=
21
replicates
and
dermal
=
16
to26
replicates.
High
confidence
in
hand/
dermal
data.

Engineering
Controls:
No
data
APPLICATOR
DESCRIPTORS
Applying
Sprays
with
a
Groundboom
Sprayer
(3)
PHED
V1.1
°
80
acres
for
groundboom
to
rhubarb
and
celeriac
Baseline:
Hand,
dermal,
and
inhalation
data
are
AB
grades.
Hand
=
29
replicates;
dermal
=
23
to
42
replicates;

and
inhalation
=
22
replicates.
High
confidence
in
hand/
dermal
and
inhalation
data.
No
protection
factor
was
needed
to
define
the
unit
exposure
value.

PPE:
The
same
dermal
and
inhalation
data
are
used
as
for
the
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing,
and
an
80%
protection
factor
to
account
for
the
use
of
a
dust/
mist
respirator
and
90%
protection
factor
to
account
for
the
use
of
an
organic
vapor
respirator,
respectively.
Hand
data
are
ABC
grades,
with
21
replicates.
Medium
confidence
in
hand/
dermal
data.

Engineering
Controls:
Hand
and
dermal
data
are
ABC
grades,
and
inhalation
are
AB
grades.
Hand
=
16
replicates;
dermal
=20
to
31
replicates;
inhalation
=
16
replicates.
Medium
confidence
in
hand/
dermal
data,
and
high
confidence
in
inhalation
data.

Footnotes
a
Standard
Assumptions
based
on
an
8­
hour
work
day
as
estimated
by
HED.
BEAD
data
were
not
available.

b
All
handler
exposure
assessments
in
this
document
are
based
on
the
"Best
Available"
data
as
defined
by
OREB
SOP
for
meeting
Subdivision
U
Guidelines.
Best
available
grades
are
assigned
to
data
as
follows:
matrices
with
grades
A
and
B
data
and
a
minimum
of
15
replicates;
if
not
available,
then
grades
A,
B
and
C
data
and
a
minimum
of
15
replicates;
if
not
available,
then
all
data
regardless
of
the
quality
(i.
e.,
All
Grade
Data)
and
number
of
replicates.
High
quality
data
with
a
protection
factor
take
precedence
over
low
quality
data
with
no
protection
factor.
Generic
data
confidence
categories
are
assigned
as
follows:
12
High
=
grades
A
and
B
and
15
or
more
replicates
per
body
part
Medium
=
grades
A,
B,
and
C
and
15
or
more
replicates
per
body
part
Low
=
grades
A,
B,
C,
D
and
E
or
any
combination
of
grades
with
less
than
15
replicates
Summary
of
Non­
Cancer
Risk
Concerns
for
Occupational
Handlers
For
the
dermal
and
inhalation,
short­
term
exposure,
the
target
MOE
is
100.
The
calculated
dermal
and
inhalation
MOE
values
were
combined
for
short­
term
because
the
dermal
and
inhalation
endpoints
were
the
same.
MOEs
are
calculated
for
all
scenarios
at
baseline,
minimum
PPE,
maximum
PPE,
and
engineering
control
level
exposures.

Baseline
Level
The
calculations
of
short­
term
combined
dermal
and
inhalation
risk
indicate
that
the
only
scenarios
with
MOEs
that
are
less
than
the
target
MOE
of
100
at
the
baseline
level
are
the
following:

°
(1a)
mixing/
loading
liquids
for
groundboom
application
to
rhubarb
and
celeriac
at
80
acres
per
day;
and
°
(1b)
mixing/
loading
liquids
for
chemigation
application
to
rhubarb
and
celeriac
at
350
acres
per
day.

Additional
PPE
The
calculations
of
short­
term
combined
dermal
and
inhalation
risk
indicate
that
all
the
scenarios
have
MOEs
that
exceed
the
target
MOE
of
100
at
the
additional
PPE
level.

Engineering
Controls
The
calculations
of
short­
term
combined
dermal
and
inhalation
risk
indicate
that
all
the
scenarios
have
MOEs
that
exceed
the
target
MOE
of
100
at
the
engineering
control
level.

Occupational
Handler
Exposure
and
Risk
Estimates
for
Cancer
Linuron
cancer
classification
is
"Suggestive
evidence
of
carcinogenic
potential
by
all
routes
of
exposure,
but
not
sufficient
to
assess
human
carcinogenic
potential"
therefore
a
occupational
handler
cancer
assessment
was
not
conducted.
Occupational
Post
Application
Exposures
and
Non­
Cancer
Risk
Estimates
Linuron
is
in
toxicity
category
III
and
IV
for
the
dermal
route
of
exposure,
primary
eye
irritation,
and
primary
skin
irritation.
Linuron
is
not
a
dermal
sensitizer.
Based
on
the
Worker
13
Protection
Standard
(WPS),
an
interim
REI
of
12
hours
is
sufficient
to
protect
workers
performing
re­
entry
activities
for
the
proposed
use
of
linuron.

The
WPS
prohibits
routine
entry
to
perform
hand
labor
tasks
during
the
REI
and
requires
PPE
to
be
worn
for
other
early­
entry
tasks
that
require
contact
with
treated
surfaces.
The
linuron
labels
specify
the
following
early
entry
PPE:
coveralls
over
short­
sleeved
shirt
and
short
pants,
waterproof
gloves,
shoes,
socks,
and
chemical
resistant
headgear
for
overhead
exposure.

The
transfer
coefficients
used
in
this
assessment
for
the
use
on
rhubarb
and
celeriac
are
from
the
Agricultural
Re­
entry
Task
Force
(ARTF)
database.
An
interim
transfer
coefficient
policy
was
developed
by
HED's
Science
Advisory
Council
for
Exposure
using
the
ARTF
database.
It
is
the
intention
of
HED's
Science
Advisory
Council
for
Exposure
that
this
policy
will
be
periodically
updated
to
incorporate
additional
information
about
agricultural
practices
in
crops
and
new
data
on
transfer
coefficients.
Much
of
this
information
will
originate
from
exposure
studies
currently
being
conducted
by
the
ARTF,
from
the
further
analysis
of
studies
already
submitted
to
the
Agency,
and
from
the
studies
in
the
published
scientific
literature.
8,9
Although
rhubarb
and
celeriac
are
not
specifically
listed
in
the
EPA
Policy
3.1,
the
transfer
coefficient
for
celery,
a
similar
crop,
was
used
as
a
surrogate.

The
rhubarb
and
celeriac
surrogate
assessments
use
a
low
transfer
coefficient
of
500
cm
2
/hr
for
activities
such
as
scouting
during
minimal
foliage
development.
8
The
linuron
labels
indicates
that
it
is
applied
pre­
emergent
to
rhubarb
and
post­
emergent
but
before
a
height
of
eight
inches
is
reached
to
celeriac.
4,5
Therefore,
the
high
transfer
coefficient
for
activities,
such
as
scouting
during
full
foliage,
will
not
be
used.
No
chemical
specific
dislodgeable
foliar
residue
(DFR)
or
turf
transferable
residue
(TTR)
data
exist.
The
DFR
is
derived
from
using
an
estimated
20
percent
of
the
rate
applied
as
initial
dislodgeable
residues
for
rhubarb
and
celeriac.
An
estimated
10
percent
dissipation
rate
per
day
for
rhubarb
and
celeriac.
The
duration
of
postapplication
exposure
is
assumed
to
be
short­
term.

The
equations
used
to
calculate
the
post­
application
in
Table
6
are
presented
below:

Surrogate
DFR
calculation
(rhubarb
and
celeriac):

Where:
AR
=
Application
rate
(1.5
lbs
ai/
acre
for
rhubarb
and
celeriac)
DR
=
Daily
dissipation
rate
(10
percent/
day)
t
=
Days
after
treatment
CF
=
Conversion
factor
(11.2
µg
per
cm
2
/lb
ai
per
A)
F
=
Fraction
retained
on
foliage
(20%
for
rhubarb
and
celeriac)
14
Dose
calculation:

Where:
DFR
=
Initial
DFR
or
daily
DFR
(µg/
cm
2
)
Tc
=
Transfer
coefficient
(500
cm
2
/hr
for
rhubarb
and
celeriac)
CF
=
Conversion
factor
(1
mg/
1,000
µg)
ED
=
Exposure
duration
(8
hours
per
day)
BW
=
Body
weight
(70
kg)

Where:
NOAEL
=
5.8
mg/
kg/
day
Dose
=
Calculated
dose
(mg/
kg/
day)

Occupational
Post­
application
Non­
cancer
Risk
Summary
For
non­
cancer
risks,
the
calculated
MOE
for
rhubarb
and
celeriac
exceeds
the
target
MOE
on
the
day
of
application
for
activities
such
as
handweeding,
scouting,
and
irrigating
(see
table
6).
15
Table
6.
Linuron
Non­
Cancer
Post
application
Assessment
Crop
Maximum
Label
Application
Rate
(lbs
ai/
acre)
a
Transfer
Coefficient
b
(cm
2
/hr)
Activity
c
DAT
d
DFR
e
(µg/
cm
2
)
MOE
f
Rhubarb
and
Celeriac
1.5
500
hand
weeding,
scouting,
and
irrigating
0
(12
hours)
3.36
190
Footnotes:
a
Maximum
application
rates
as
proposed
for
linuron
use
on
rhubarb
and
celeriac.
b
Transfer
Coefficients
from
Science
Advisory
Council
on
Exposure
Policy
3.1.
7
c
Activities
from
Science
Advisory
Council
on
Exposure
Policy
3.1.
7
Every
activity
listed
may
not
occur
for
every
crop
in
the
group.
d
DAT
is
"days
after
treatment"
e
Initial
DFR
(µg/
cm
2
)
=
Application
rate
(lbs
ai/
A)
x
Conversion
factor
(1
lb
ai/
acre=
11.209
µg/
cm2)
x
Fraction
of
initial
ai
retained
on
foliage
(20%)
f
MOE
=
NOAEL
(mg/
kg/
day)
/
Dermal
dose
(mg/
kg/
day).
Target
MOE
=
100.

Occupational
Post­
application
Exposure
and
Risk
Estimates
for
Cancer
Linuron
was
classified
as
an
unquantifiable
Group
C
carcinogen
(a
possible
human
carcinogen
for
which
there
is
limited
animal
evidence)
requiring
no
quantification
of
human
cancer
risk;
therefore,
an
occupational
handler
cancer
assessment
was
not
conducted.

Residential
Exposure
and
Risks
Spray
drift
is
always
a
potential
source
of
exposure
to
residents
nearby
to
spraying
operations.
This
is
particularly
the
case
with
aerial
application,
but
to
a
lesser
extent,
groundboom
application
methods
could
also
be
a
potential
source
of
exposure.
The
Agency
has
been
working
with
the
Spray
Drift
Task
Force,
EPA
Regional
Offices
and
State
Lead
Agencies
for
pesticide
regulation
and
other
parties
to
develop
the
best
spray
drift
management
practices.
The
Agency
is
now
requiring
interim
mitigation
measures
for
aerial
applications
that
must
be
placed
on
product
labels/
labeling.
The
Agency
has
completed
its
evaluation
of
the
new
data
base
submitted
by
the
Spray
Drift
Task
Force,
a
membership
of
U.
S.
pesticide
registrants,
and
is
developing
a
policy
on
how
to
appropriately
apply
the
data
and
the
AgDRIFT
computer
model
to
its
risk
assessments
for
pesticides
applied
by
air,
orchard
airblast
and
ground
hydraulic
methods.
After
the
policy
is
in
place,
the
Agency
may
impose
further
refinements
in
spray
drift
management
practices
to
reduce
off­
target
drift
and
risks
associated
with
aerial
as
well
as
other
application
types
where
appropriate.

HED
has
determined
that,
other
than
the
possibility
of
spray
drift
exposure,
there
are
no
potential
post­
application
exposures
to
residents
because
linuron
is
not
used
in
any
residential
areas.
16
Incident
Reports
The
Agency
searched
several
databases
for
reports
of
poisoning
incident
data
for
linuron.
These
databases
include
the
OPP
Incident
Data
System,
the
Poison
Control
Centers
database,
the
California
Department
of
Pesticide
Regulation,
and
the
National
Pesticide
Telecommunications
Network.
Relatively
few
incidents
of
illness
have
been
reported.
Three
cases
were
submitted
to
the
California
Pesticide
Illness
Surveillance
Program
(1982­
1999)
concerning
possible
linuron
poisoning.
Effects
reported
in
these
cases
include
chemical
conjuctivitis
when
linuron
was
splashed
into
the
eyes,
headache,
nausea,
swollen
tongue
and
blurred
vision,
and
itchy
hives.
According
to
the
fifth
edition
of
"Recognition
and
Management
of
Pesticide
Poisonings"
(EPA
1999),
systemic
toxicity
is
unlikely
unless
large
amounts
have
been
ingested.
No
recommendations
can
be
made
based
on
the
few
incident
reports
available
for
linuron.
1
17
References
1.
Blondell,
J.
and
M.
Spann
(2001)
Review
of
Linuron
Incident
Reports
DP
Barcode
D280196,
Chemical
#035506.
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.
January
11,
2001.

2.
Christensen,
C.
(2001)
Linuron
­
Report
of
the
FQPA
Safety
Factor
Committee.
Washington,
D.
C.:
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.
December
6,
2001.

3.
Fricke,
R.
(2001)
Linuron:
Report
of
the
Hazard
Identification
Assessment
Review
Committee.
Washington,
D.
C.:
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.
November
20,
2001.

4.
Interregional
Research
Project
No.
4
(1998)
Petition
Re:
Linuron/
Rhubarb/
PR#­
06591,
New
Use,
No
date
for
review.
Interregional
Research
Project
No.
4.
Center
for
Minor
Crop
Pest
Management.
Letter
from
Edith
Lurvey
(IR­
4)
to
Hoyt
Jamerson
(MUERIB/
RD/
OPP),
August
20,
1998.

5.
Interregional
Research
Project
No.
4
(1998)
Petition
Re:
Linuron/
Celeriac/
PR#­
03557,
New
Use,
No
date
for
review.
Interregional
Research
Project
No.
4.
Center
for
Minor
Crop
Pest
Management.
Letter
from
Edith
Lurvey
(IR­
4)
to
Hoyt
Jamerson
(MUERIB/
RD/
OPP),
August
20,
1998.

6.
U.
S.
EPA
(1998)
PHED
Surrogate
Exposure
Guide,
Version
1.1.
Washington,
D.
C.:
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.
August
1998.

7.
U.
S.
EPA
(1999)
Use
of
Values
from
the
PHED
Surrogate
Table
and
Chemical­
specific
Data,
Science
Advisory
Council
for
Exposure
Policy
No.
7.
Washington,
D.
C.:
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.
January
28,
1999.

8.
U.
S.
EPA
(2001)
Agricultural
Transfer
Coefficients,
Science
Advisory
Council
for
Exposure
Policy
No.
3.1.
Washington,
D.
C.:
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.
August
7,
2000.

9.
U.
S.
EPA
(2001)
Revised
­
Standard
Values
for
Daily
Acres
Treated
in
Agriculture,
Science
Advisory
Council
for
Exposure
Policy
No.
9.1.
Washington,
D.
C.:
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.
September
25,
2001.
18
Appendix
19
Table
A.
Occupational
Handler
Short­
Term
Risk
to
Linuron
at
Baseline
Exposure
Scenario
(Scenario
#)
Dermal
Unit
Exposure
(mg/
lb
ai)
a
Inhalation
Unit
Exposure
b
(Ug/
lb
ai)
Crop
Application
Rate
c
Amount
Treated
Dermal
Dose
(mg/
kg/
day)
d
Dermal
MOE
e
Inhalation
Dose
(mg/
kg/
day)
f
Inhalation
MOE
g
Total
MOE
h
Mixer/
Loader
Mixing/
Loading
Liquids
for
Groundboom
application
(1)
2.9
1.
2
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.80
7
0.
0021
2800
7.3
Dry
Flowables
for
Groundboom
application
(2)
0.066
0.77
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.018
320
0.0013
4400
300.0
Mixing/
Loading
Liquids
for
Chemigation
application
(3)
2.9
1.
2
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
350
Acres
per
day
3.5
2
0.009
640
1.7
Applicator
Sprays
for
Groundboom
application
(4)
0.014
0.74
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.0038
1500
0.0013
4600
1100.0
Footnotes:
a
Baseline
dermal
unit
exposure
represents
long
pants,
long
sleeved
shirt,
no
gloves,
open
mixing/
loading,
and
open
cab
tractor
b
Baseline
inhalation
unit
exposure
represents
no
respirator.

c
Application
rates
are
based
on
the
maximum
application
rates
listed
on
the
proposed
linuron
labels.

d
Daily
Dermal
Dose
(mg/
kg/
day)
=
Dermal
Unit
Exposure
(mg/
lb
ai)*
Application
Rate
(lb
ai/
acre)*
Amount
Treated
(acres/
day)*
dermal
absorption
(16%)/
Body
Weight
(70
kg)).

e
Dermal
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Dermal
Dose
(mg/
kg/
day)
.
The
target
MOE
value
is
100.

f
Daily
Inhalation
Dose
(mg/
kg/
day)
=
(Inhalation
Unit
Exposure
(mg/
lb
ai)
*
Application
Rate
(lb
ai/
acre)
*
Amount
Treated
(acres/
day)*
1mg/
1000µg)
/
Body
weight
(70kg).

g
Inhalation
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Inhalation
Dose
(mg/
kg/
day).
The
target
MOE
value
is
100.

h
Total
MOE
(combined
dermal
and
inhalation)
=
1
/
((
1/
dermal
MOE)
+
(1/
inhalation
MOE)).
The
target
MOE
value
is
100.
20
Table
B.
Occupational
Handler
Short­
Term
Risk
to
Linuron
with
Minimum
PPE
Exposure
Scenario
(Scenario
#)
Dermal
Unit
Exposure
(mg/
lb
ai)
a
Inhalation
Unit
Exposure
b
(Ug/
lb
ai)
Crop
Application
Rate
c
Amount
Treated
Dermal
Dose
(mg/
kg/
day)
d
Dermal
MOE
e
Inhalation
Dose
(mg/
kg/
day)
f
Inhalation
MOE
g
Total
MOE
h
Mixer/
Loader
Mixing/
Loading
Liquids
for
Groundboom
application
(1)
0.023
0.24
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.0063
920
0.00041
14000
860.0
Dry
Flowables
for
Groundboom
application
(1b)
0.066
0.15
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.018
320
0.00026
23000
320.0
Mixing/
Loading
Liquids
for
Chemigation
application
(2)
0.023
0.24
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
350
Acres
per
day
0.028
210
0.0018
3200
200.0
Applicator
Sprays
for
Groundboom
application
(3)
0.014
0.15
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.0038
1500
0.00026
23000
1400.0
Footnotes
:

a
Baseline
dermal
unit
exposure
represents
long
pants,
long
sleeved
shirt,
no
gloves,
open
mixing/
loading,
and
open
cab
tractor
b
Baseline
inhalation
unit
exposure
represents
no
respirator.

c
Application
rates
are
based
on
the
maximum
application
rates
listed
on
the
proposed
linuron
labels.

d
Daily
Dermal
Dose
(mg/
kg/
day)
=
Dermal
Unit
Exposure
(mg/
lb
ai)*
Application
Rate
(lb
ai/
acre)*
Amount
Treated
(acres/
day)*
dermal
absorption
(16%)/
Body
Weight
(70
kg)).

e
Dermal
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Dermal
Dose
(mg/
kg/
day)
.
The
target
MOE
value
is
100.

f
Daily
Inhalation
Dose
(mg/
kg/
day)
=
(Inhalation
Unit
Exposure
(mg/
lb
ai)
*
Application
Rate
(lb
ai/
acre)
*
Amount
Treated
(acres/
day)*
1mg/
1000µg)
/
Body
weight
(70kg).

g
Inhalation
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Inhalation
Dose
(mg/
kg/
day).
The
target
MOE
value
is
100.

h
Total
MOE
(combined
dermal
and
inhalation)
=
1
/
((
1/
dermal
MOE)
+
(1/
inhalation
MOE)).
The
target
MOE
value
is
100.
21
Table
C.
Occupational
Handler
Short­
Term
Risk
to
Linuron
with
Maximum
PPE
Exposure
Scenario
(Scenario
#)
Dermal
Unit
Exposure
(mg/
lb
ai)
a
Inhalation
Unit
Exposure
b
(Ug/
lb
ai)
Crop
Application
Rate
c
Amount
Treated
Dermal
Dose
(mg/
kg/
day)
d
Dermal
MOE
e
Inhalation
Dose
(mg/
kg/
day)
f
Inhalation
MOE
g
Total
MOE
h
Mixer/
Loader
Mixing/
Loading
Liquids
for
Groundboom
application
(1)
0.017
0.12
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.0047
1200
0.00021
28000
1200.0
Dry
Flowables
for
Groundboom
application
(1b)
0.047
0.077
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.013
450
0.00013
44000
450.0
Mixing/
Loading
Liquids
for
Chemigation
application
(2)
0.017
0.12
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
350
Acres
per
day
0.020
280
0.0009
6400
270.0
Applicator
Sprays
for
Groundboom
application
(3)
0.011
0.074
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.0030
1900
0.00013
46000
1800.0
Footnotes
:

a
Baseline
dermal
unit
exposure
represents
long
pants,
long
sleeved
shirt,
no
gloves,
open
mixing/
loading,
and
open
cab
tractor
b
Baseline
inhalation
unit
exposure
represents
no
respirator.

c
Application
rates
are
based
on
the
maximum
application
rates
listed
on
the
proposed
linuron
labels.

d
Daily
Dermal
Dose
(mg/
kg/
day)
=
Dermal
Unit
Exposure
(mg/
lb
ai)*
Application
Rate
(lb
ai/
acre)*
Amount
Treated
(acres/
day)*
dermal
absorption
(16%)/
Body
Weight
(70
kg)).

e
Dermal
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Dermal
Dose
(mg/
kg/
day)
.
The
target
MOE
value
is
100.

f
Daily
Inhalation
Dose
(mg/
kg/
day)
=
(Inhalation
Unit
Exposure
(mg/
lb
ai)
*
Application
Rate
(lb
ai/
acre)
*
Amount
Treated
(acres/
day)*
1mg/
1000µg)
/
Body
weight
(70kg).

g
Inhalation
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Inhalation
Dose
(mg/
kg/
day).
The
target
MOE
value
is
100.

h
Total
MOE
(combined
dermal
and
inhalation)
=
1
/
((
1/
dermal
MOE)
+
(1/
inhalation
MOE)).
The
target
MOE
value
is
100.
22
Table
D.
Occupational
Handler
Short­
Term
Risk
to
Linuron
with
Engineering
Controls
Exposure
Scenario
(Scenario
#)
Dermal
Unit
Exposure
(mg/
lb
ai)
a
Inhalation
Unit
Exposure
b
(Ug/
lb
ai)
Crop
Application
Rate
c
Amount
Treated
Dermal
Dose
(mg/
kg/
day)
d
Dermal
MOE
e
Inhalation
Dose
(mg/
kg/
day)
f
Inhalation
MOE
g
Total
MOE
h
Mixer/
Loader
Mixing/
Loading
Liquids
for
Groundboom
application
(1)
0.0086
0.083
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.0024
2500
0.00014
41000
2300.0
Dry
Flowables
for
Groundboom
application
(1b)
No
Data
No
Data
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
No
Data
No
Data
No
Data
No
Data
Mixing/
Loading
Liquids
for
Chemigation
application
(2)
0.0086
0.083
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
350
Acres
per
day
0.010
560
0.00062
9300
530.0
Applicator
Sprays
for
Groundboom
application
(3)
0.005
0.043
Rhubarb,
Celeriac
1.50
lb
ai
per
acre
80
Acres
per
day
0.0014
4200
0.000074
79000
4000.0
Footnotes
:

a
Baseline
dermal
unit
exposure
represents
long
pants,
long
sleeved
shirt,
no
gloves,
open
mixing/
loading,
and
open
cab
tractor
b
Baseline
inhalation
unit
exposure
represents
no
respirator.

c
Application
rates
are
based
on
the
maximum
application
rates
listed
on
the
proposed
linuron
labels.

d
Daily
Dermal
Dose
(mg/
kg/
day)
=
Dermal
Unit
Exposure
(mg/
lb
ai)*
Application
Rate
(lb
ai/
acre)*
Amount
Treated
(acres/
day)*
dermal
absorption
(16%)/
Body
Weight
(70
kg)).

e
Dermal
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Dermal
Dose
(mg/
kg/
day)
.
The
target
MOE
value
is
100.

f
Daily
Inhalation
Dose
(mg/
kg/
day)
=
(Inhalation
Unit
Exposure
(mg/
lb
ai)
*
Application
Rate
(lb
ai/
acre)
*
Amount
Treated
(acres/
day)*
1mg/
1000µg)
/
Body
weight
(70kg).

g
Inhalation
MOE
=
NOAEL
(5.8
mg/
kg/
day)
/
Daily
Inhalation
Dose
(mg/
kg/
day).
The
target
MOE
value
is
100.

h
Total
MOE
(combined
dermal
and
inhalation)
=
1
/
((
1/
dermal
MOE)
+
(1/
inhalation
MOE)).
The
target
MOE
value
is
100.
