Document ID: EPA-HQ-OPP-2005-0495-0007
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2005-12-21T05:00Z

Page
1
of
63
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
MEMORANDUM
Date:
August
31,
2005
Subj:
Imazapyr:
Occupational
and
Residential
Exposure
Assessment
for
the
Reregistration
Eligibility
Decision
Document.

PC
Code:
128821
(
Imazapyr)
DP
Barcode:
D320582
From:
Charles
Smith,
Environmental
Scientist
Health
Effects
Division/
Reregistration
Branch
2
(
7509C)

Through:
Alan
Nielsen,
Branch
Senior
Scientist
Health
Effects
Division/
Reregistration
Branch
2
(
7509C)

To:
Christina
Jarvis,
Risk
Assessor
Health
Effects
Division/
Registration
Action
Branch
2
(
7509C)

The
attached
assessment
is
the
occupational
and
non­
occupational
(
residential)
exposure
and
risk
estimates
for
imazapyr
to
support
HED's
Reregistration
Eligibility
Decision
(
RED)
document.
Page
2
of
63
Table
of
Contents
Executive
Summary
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Page
4
of
62
1.0
Occupational
and
Residential
Exposure/
Risk
Assessment
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Page
7
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62
1.1
Purpose
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Page
7
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62
1.2
Criteria
for
Conducting
Exposure
Assessments
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Page
7
of
62
1.3
Summary
of
Hazard
Concerns
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Page
7
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62
1.3.1
Imazapyr
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Page
7
of
62
1.4
Incident
Reports
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Page
10
of
62
1.4.1
Human
Incident
Reports
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Page
10
of
62
1.5
Summary
of
Physical
and
Chemical
Properties
of
Imazapyr
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Page
10
of
62
1.6
Summary
of
Use
Patterns
and
Formulations
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Page
10
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62
1.6.1
End­
Use
Products
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Page
10
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62
1.6.2
Registered
Use
Categories
and
Sites
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Page
10
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62
1.6.3
Application
Methods
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Page
12
of
62
2.0
Occupational
Exposures
and
Risks
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Page
12
of
62
2.1
Occupational
Handler
Exposures
and
Risks
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Page
12
of
62
2.1.1
Data
and
Assumptions
For
Handler
Exposure
Scenarios
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Page
14
of
62
2.1.1.1
Assumptions
for
Handler
Exposure
Scenarios
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Page
14
of
62
2.1.1.2
Exposure
Data
for
Handler
Exposure
Scenarios
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Page
15
of
62
2.1.2
Imazapyr
Handler
Exposure
Scenarios
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Page
23
of
62
2.1.3
Non­
cancer
Imazapyr
Handler
Exposure
and
Assessment
.
.
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Page
24
of
62
2.1.3.1
Non­
cancer
Imazapyr
Handler
Exposure
and
Risk
Calculations
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Page
24
of
62
2.1.3.2
Imazapyr
Non­
cancer
Risk
Summary
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Page
26
of
62
2.1.4
Summary
of
Risk
Concerns
and
Data
Gaps
for
Occupational
Handlers
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Page
30
of
62
2.1.4.1
Summary
of
Risk
Concerns
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Page
30
of
62
2.1.4.2
Summary
of
Data
Gaps
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Page
30
of
62
2.1.5
Recommendations
For
Refining
Occupational
Handler
Risk
Assessment
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Page
30
of
62
2.2
Occupational
Postapplication
Exposures
and
Risks
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Page
30
of
62
2.2.1
Occupational
Postapplication
Exposure
Scenarios
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Page
31
of
62
2.2.2
Data/
Assumptions
for
Postapplication
Exposure
Scenarios
.
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Page
33
of
62
2.2.3
Occupational
Postapplication
Exposure
and
Non­
cancer
Risks
.
.
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Page
34
of
62
2.2.4
Off
Target
Non­
Occupational
Exposure
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Page
35
of
62
2.2.5
Summary
of
Occupational
Postapplication
Risk
Concerns
and
Data
Gaps
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Page
36
of
62
2.2.6
Recommendations
For
Refining
Occupational
Postapplication
Risk
assessment
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Page
36
of
62
3.0
Residential
and
Other
Non­
Occupational
Exposures
and
Risks
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Page
36
of
62
3.1
Residential
Handler
Exposures
and
Risks
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Page
36
of
62
3.1.1
Handler
Exposure
Scenarios
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Page
36
of
62
Page
3
of
63
3.1.2
Data
and
Assumptions
For
Handler
Exposure
Scenarios
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Page
37
of
62
3.1.3
Residential
Handler
Exposure
and
Non­
Cancer
Risk
Estimates
.
.
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Page
40
of
62
Noncancer
Risk
Summary:
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Page
40
of
62
3.1.4
Summary
of
Risk
Concerns
and
Data
Gaps
for
Handlers
.
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Page
41
of
62
3.1.5
Recommendations
For
Refining
Residential
Handler
Risk
Assessment
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Page
41
of
62
3.2
Residential
Postapplication
Exposures
and
Risks
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Page
41
of
62
3.2.1
Residential
Postapplication
Exposure
Scenarios
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Page
41
of
62
3.2.2
Data
and
Assumptions
for
Residential
Postapplication
Exposure
Scenarios
.
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Page
44
of
62
3.2.3
Residential
Postapplication
Exposure
and
Noncancer
Risk
Estimates
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Page
45
of
62
3.2.4
Residential
Postapplication
Noncancer
Risk
Summary
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Page
48
of
62
3.2.5
Summary
of
Residential
Postapplication
Risk
Concerns
and
Data
Gaps
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Page
51
of
62
3.2.6
Recommendations
For
Refining
Residential
Postapplication
Risk
Assessment
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Page
51
of
62
Appendix
A:
Occupational
Handler
Exposures
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Page
52
of
62
Appendix
B:
Residential
Handler
Exposures
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Page
60
of
62
Page
4
of
63
Executive
Summary
The
Health
Effects
Division
(
HED)
has
conducted
an
occupational
and
non­
occupational
(
residential)
exposure
assessment
for
the
active
ingredient
imazapyr
[
2­(
4­
isopropyl­
4­
methyl­
5­
oxo­
2­
imidazolin­
2­
yl)­
nicotinic
acid]
for
the
purpose
of
supporting
HED's
Reregistration
Eligibility
Decision
(
RED)
document.

Use
and
Usage
Summary
Imazapyr
is
an
herbicide
used
in
the
United
States
in
agricultural,
commercial,
and
residential
settings.
Imazapyr
is
formulated
as
an
liquid,
a
wettable
powder
(
including
water
soluble
bags),
and
a
granular.

Hazard
Profile
Imazapyr
has
low
acute
toxicity
via
the
oral,
dermal
and
inhalation
routes
of
exposure.
It
is
not
irritating
to
the
skin
and
is
negative
for
dermal
sensitization.
However,
imazapyr
is
corrosive
to
the
eye
(
toxicity
category
I).

The
incidental
oral
toxicological
endpoint
of
concern
(
250
mg/
kg/
day)
is
the
same
for
short­,
and
intermediate­
term
oral
exposures.
It
was
selected
from
a
1­
year
dog
feeding
study
based
on
the
skeletal
muscle
effects
observed
in
the
dog
with
a
structural
analog,
imazapic.
With
imazapic
there
were
skeletal
muscle
effects
in
dogs
at
5000
ppm
(
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females).
Although
there
were
no
skeletal
muscle
effects
or
any
other
adverse
effects
seen
with
imazapyr
up
to
250
mg/
kg/
day
the
HIARC
noted
that
one
cannot
say
that
effects
with
imazapyr
would
not
have
occurred
had
dosing
been
higher.
The
dermal
and
inhalation
toxicological
endpoint
of
concern
are
both
the
same
as
the
oral
study.
Since
an
oral
dose
was
selected,
and
there
is
no
information
on
dermal
penetration
for
imazapyr,
a
100%
default
dermal
absorption
factor
(
oral
equivalent)
was
used
for
route­
to­
route
extrapolation.
Absorption
via
the
inhalation
route
is
presumed
to
be
equivalent
to
oral
absorption
(
100%).
The
dermal
and
inhalation
risks
were
combined
for
this
assessment,
because
the
adverse
effects
for
the
dermal
and
inhalation
routes
of
exposure
were
the
same
(
skeletal
muscle
effects).

HED's
level
of
concern
for
noncancer
risks
(
i.
e.,
target
level
for
MOEs
or
Margins
of
Exposure)
is
defined
by
the
uncertainty
factors
that
are
applied
to
the
assessment.
HED
applies
a
10X
factor
to
account
for
interspecies
extrapolation
and
a
10X
factor
to
account
for
intraspecies
sensitivity.
The
total
uncertainty
factors
that
have
been
applied
to
noncancer
risk
assessments
is
100
for
occupational
and
residential
scenarios.

Imazapyr
was
classified
by
the
Cancer
Peer
Review
Committee
(
CPRC)
in
October
1995
as
a
"
Group
E
chemical,"
no
evidence
of
carcinogenicity
in
at
least
2
adequate
studies
in
the
rat
and
mouse"
(
TXR
#
0050019).
This
decision
was
reaffirmed
on
May
22,
2003
(
TXR
#
0051943).
A
quantitative
cancer
risk
assessment
is
not
required
for
imazapyr.
Imazapyr
was
negative
for
Page
5
of
63
mutagenic
potential
in
the
Salmonella
assay,
CHO
HGPRT
gene
mutation
assay,
in
vitro
chromosomal
aberration
assay
in
CHO
cells
and
in
a
dominant
lethal
assay
in
mice.

Occupational
Handler
Noncancer
Risks
The
noncancer
occupational
handler
risk
assessment
indicates
that
for
most
scenarios,
risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
at
either
baseline
PPE
or
with
the
addition
of
chemical­
resistant
gloves.
With
respect
to
the
application
of
sprays
or
granules
with
aircraft,
the
only
data
available
are
for
enclosed
cockpits
which
is
an
engineering
control.
Risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
with
the
use
of
enclosed
cockpit
engineering
controls.

Occupational
Postapplication
Noncancer
Risks
Agricultural
Crop
Scenarios:
The
noncancer
occupational
postapplication
worker
risk
assessment
indicates
that
for
all
agricultural
postapplication
exposure
scenarios,
postapplication
occupational
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
on
day
0
 
approximately
12
hours
following
application.

Residential
Handler
Noncancer
Risks
The
noncancer
residential
handler
risk
assessment
indicates
that
for
all
scenarios,
risks
are
below
HED's
level
of
concern
(
i.
e.,
MOEs
are
greater
than
100)
assuming
handlers
are
wearing
shortsleeve
shirt,
short
pants,
shoes,
and
socks.

Residential
Postapplication
Noncancer
Risks
Adult
short­
term
residential
postapplication
risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
for
all
scenarios.

Toddler
(
3
year
old)
short­
term
residential
postapplication
risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
for
all
scenarios.

HED
combines
risk
values
resulting
from
separate
postapplication
exposure
scenarios
when
it
is
likely
they
can
occur
simultaneously
based
on
the
use­
pattern
and
the
behavior
associated
with
the
exposed
population.
The
combined
risks
for
the
turf
spray
scenario
(
dermal
and
nondietary
oral
exposures
to
toddles)
is
410
and
is
below
HED's
level
of
concern.

Overall
Risk
Summary
and
Data
Gaps
For
most
scenarios,
risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
at
either
baseline
PPE
or
with
the
addition
of
chemical­
resistant
gloves.
With
respect
to
the
application
of
sprays
or
granules
with
aircraft,
the
only
data
available
are
for
enclosed
cockpits,
an
Page
6
of
63
engineering
control.
Risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
with
the
use
of
enclosed
cockpit
engineering
controls.
A
few
data
gaps
were
identified
for
imazapyr
in
a
few
different
use
areas
that
include:

S
applying
sprayers
to
aquatic
sites
via
helicopters
(
PHED
data
for
fixed
wind
aerial
spray
applications
were
used
as
a
reasonable
surrogate);
and
S
mixing/
loading/
applying
liquids
to
trees
via
injection
equipment
(
no
surrogate
data
are
available
at
this
time).

For
all
agricultural
postapplication
exposure
scenarios,
postapplication
occupational
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
on
day
0
 
approximately
12
hours
following
application.
HED
has
used
the
latest
information
to
complete
this
postapplication
risk
assessment
for
imazapyr.
Data
gaps
exist
such
as
a
lack
of
imazapyr
specific
postapplication
studies.

Noncancer
residential
handler
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
for
all
residential
handler
scenarios.
No
key
data
gaps
have
been
identified
by
HED
at
this
time
for
residential
handlers.

Residential
postapplication
risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
less
than
100)
for
dermal
and
nondietary
oral
postapplication
exposures
to
toddlers
from
turf
pesticide
treatments.
For
the
turf
uses,
dermal
and
hand­
to­
mouth
exposures
are
the
key
contributors
to
the
overall
estimates.
HED
combines
risks
resulting
from
different
routes
of
exposures
to
individuals
when
it
is
likely
they
can
occur
simultaneously
based
on
the
use
pattern
and
the
behavior
associated
with
the
exposed
population.
For
imazapyr,
HED
has
combined
risk
values
(
i.
e.,
MOEs)
for
different
routes
of
exposures
associated
with
the
turf
scenario
(
dermal,
hand­
tomouth
object­
to­
mouth,
and
soil
ingestion).
These
are
typically
added
together
when
pesticides
are
used
on
turf,
because
it
is
logical
they
can
co­
occur.
These
combined
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100).
Page
7
of
63
1.0
Occupational
and
Residential
Exposure/
Risk
Assessment
1.1
Purpose
This
document
is
the
occupational
and
residential
non­
dietary
exposure
and
risk
assessment
for
the
systemic
herbicide
imazapyr.
In
this
document,
which
is
for
use
in
EPA's
development
of
the
HED
chapter
of
the
imazapyr
Reregistration
Eligibility
Decision
(
RED)
Document,
EPA
presents
the
results
of
its
review
of
the
potential
human
health
effects
of
occupational
and
residential/
nonoccupational
exposure
to
imazapyr.

1.2
Criteria
for
Conducting
Exposure
Assessments
An
occupational
and/
or
residential
exposure
assessment
is
required
for
an
active
ingredient
if
(
1)
certain
toxicological
criteria
are
triggered
and
(
2)
there
is
a
potential
for
exposure
to
handlers
(
mixers,
loaders,
applicators)
during
use
or
to
persons
entering
treated
sites
or
exposed
to
vapors
after
application
is
complete.
Toxicological
endpoints
were
selected
for
short­
and
intermediateterm
dermal,
incidental
oral,
and
inhalation
exposures
to
imazapyr.
There
is
potential
for
exposure
in
a
variety
of
occupational
agricultural
and
commercial
settings
as
well
as
in
residential
settings.
Therefore,
risk
assessments
are
required
for
occupational
and
residential
handlers
as
well
as
for
occupational
and
residential
postapplication
exposures
that
can
occur
as
a
result
of
imazapyr
use.

1.3
Summary
of
Hazard
Concerns
HED's
Hazard
Identification
Assessment
Review
Committee
(
HIARC)
met
to
determine
appropriate
toxicological
endpoints
of
concern
for
imazapyr.
The
toxicological
endpoints
that
were
used
to
complete
the
occupational
and
residential
risk
assessments
are
summarized
below
which
have
been
extracted
from
the
Imazapyr
HIARC
report
(
02/
06/
03).
Adverse
effects
were
identified
at
all
durations
of
exposure
ranging
from
short­
term
(
up
to
30
days)
to
intermediateterm
(
1
to
6
months)
to
long­
term
(>
6
months
up
to
1
year)
durations.

1.3.1
Imazapyr
Imazapyr
is
a
systemic
herbicide
with
a
variety
of
use
patterns.
Exposure
durations
are
expected
to
range
from
short­
term
through
intermediate­
term.
The
HIARC
evaluated
the
imazapyr
toxicological
database
(
see
Table
1)
and
selected
endpoint
doses
for
short­,
intermediate­,
and
long­
term
exposures.
Imazapyr
exposures
are
expected
to
occur
to
both
occupational
and
residential
users.

Acute
Toxicity
Imazapyr
has
low
acute
toxicity
via
the
oral,
dermal
and
inhalation
routes
of
exposure.
It
is
not
irritating
to
the
skin
and
is
negative
for
dermal
sensitization.
However,
imazapyr
is
corrosive
to
Page
8
of
63
the
eye
(
toxicity
category
I).

Incidental
Oral
Route
The
HIARC
selected
the
1­
year
dog
feeding
study
with
a
NOAEL
of
250
mg/
kg/
day,
based
on
the
skeletal
muscle
effects
observed
in
the
dog
with
a
structural
analog,
imazapic.
With
imazapic
there
were
skeletal
muscle
effects
in
dogs
at
5000
ppm
(
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females).
Although
there
were
no
skeletal
muscle
effects
or
any
other
adverse
effects
seen
with
imazapyr
up
to
250
mg/
kg/
day
the
HIARC
noted
that
one
cannot
say
that
effects
with
imazapyr
would
not
have
occurred
had
dosing
been
higher.

Dermal
Route
(
all
durations)

The
HIARC
selected
the
1­
year
dog
feeding
study
with
a
NOAEL
of
250
mg/
kg/
day,
based
on
the
skeletal
muscle
effects
observed
in
the
dog
with
a
structural
analog,
imazapic.
With
imazapic
there
were
skeletal
muscle
effects
in
dogs
at
5000
ppm
(
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females).
Although
there
were
no
skeletal
muscle
effects
or
any
other
adverse
effects
seen
with
imazapyr
up
to
250
mg/
kg/
day
(
HDT)
the
HIARC
noted
that
one
cannot
say
that
effects
with
imazapyr
would
not
have
occurred
had
dosing
been
higher.
Since
an
oral
dose
was
selected,
and
there
is
no
information
on
dermal
penetration
for
imazapyr,
a
100%
default
dermal
absorption
factor
(
oral
equivalent)
was
used
for
route­
to­
route
extrapolation.

Inhalation
Route
(
all
durations)

The
HIARC
selected
the
1­
year
dog
feeding
study
with
a
NOAEL
of
250
mg/
kg/
day,
based
on
the
skeletal
muscle
effects
observed
in
the
dog
with
a
structural
analog,
imazapic.
With
imazapic
there
were
skeletal
muscle
effects
in
dogs
at
5000
ppm
(
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females).
Although
there
were
no
skeletal
muscle
effects
or
any
other
adverse
effects
seen
with
imazapyr
up
to
250
mg/
kg/
day
(
HDT)
the
HIARC
noted
that
one
cannot
say
that
effects
with
imazapyr
would
not
have
occurred
had
dosing
been
higher.
Absorption
via
the
inhalation
route
is
presumed
to
be
equivalent
to
oral
absorption
(
100%

Non­
cancer
Level
of
Concern
(
LOC)

HED's
level
of
concern
(
LOC)
for
imazapyr
is
100
(
i.
e.,
a
margin
of
exposure
­
MOE
­
less
than
100
exceeds
HED's
level
of
concern)
for
occupational
scenarios
and
residential
scenarios.
The
level
of
concern
is
based
on
10x
to
account
for
interspecies
extrapolation
to
humans
from
the
animal
test
species
and
10X
to
account
for
intraspecies
sensitivity.

Cancer
Imazapyr
was
classified
by
the
Cancer
Peer
Review
Committee
(
CPRC)
in
October
1995
as
a
Page
9
of
63
"
Group
E
chemical,"
no
evidence
of
carcinogenicity
in
at
least
2
adequate
studies
in
the
rat
and
mouse"
(
TXR
#
0050019).
This
decision
was
reaffirmed
on
May
22,
2003
(
TXR
#
0051943).
A
quantitative
cancer
risk
assessment
is
not
required
for
imazapyr.
Imazapyr
was
negative
for
mutagenic
potential
in
the
Salmonella
assay,
CHO
HGPRT
gene
mutation
assay,
in
vitro
chromosomal
aberration
assay
in
CHO
cells
and
in
a
dominant
lethal
assay
in
mice.

Body
Weight
Since
the
adverse
effects
for
all
studies
utilized
in
the
imazapyr
dermal
and
inhalation
risk
assessments
are
for
the
general
population,
the
average
weight
of
an
adult
(
i.
e.,
70
kg)
was
used
to
estimate
exposure.

Table
1.
Toxicology
Endpoints
for
Imazapyr
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
Special
FQPA
SF*
and
Level
of
Concern
for
Risk
Assessment
Study
and
Toxicological
Effects
Chronic
Dietary
NOAEL=
250
mg/
kg/
day
cPAD
==
2.5
mg/
kg/
day
No
LOAEL
was
demonstrated
with
imazapyr
at
doses
up
to
250
mg/
kg/
day
(
HDT);
HIARC
assumed
this
dose
as
an
endpoint
for
RA
for
imazapyr,
based
on
skeletal
muscle
effects
seen
in
dogs
with
structural
analog
imazapic
at
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females.

Short­
and
Intermediate­
Term
Incidental
Oral
(
1
­
30
Days)
NOAEL
=
250
mg/
kg/
day
Residential
LOC
for
MOE
=
100
No
LOAEL
was
demonstrated
with
imazapyr
at
doses
up
to
250
mg/
kg/
day
(
HDT);
HIARC
assumed
this
dose
as
an
endpoint
for
RA
for
imazapyr,
based
on
skeletal
muscle
effects
seen
in
dogs
with
structural
analog
imazapic
at
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females.

Short­,
Intermediate­,
and
Long­
Term
Dermal
(
1
­
30
days)
NOAEL
=
250
mg/
kg/
day
Residential
LOC
for
MOE
=
100
No
LOAEL
was
demonstrated
with
imazapyr
at
doses
up
to
250
mg/
kg/
day
(
HDT);
HIARC
assumed
this
dose
as
an
endpoint
for
RA
for
imazapyr,
based
on
skeletal
muscle
effects
seen
in
dogs
with
structural
analog
imazapic
at
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females.

Short­,
Intermediate­,
and
Long­
Term
Inhalation
(
1
­
30
days)
NOAEL
=
250
mg/
kg/
day
Residential
LOC
for
MOE
=
100
No
LOAEL
was
demonstrated
with
imazapyr
at
doses
up
to
250
mg/
kg/
day
(
HDT);
HIARC
assumed
this
dose
as
an
endpoint
for
RA
for
imazapyr,
based
on
skeletal
muscle
effects
seen
in
dogs
with
structural
analog
imazapic
at
137
mg/
kg/
day
in
males
and
180
mg/
kg/
day
in
females.
Page
10
of
63
1.4
Incident
Reports
1.4.1
Human
Incident
Reports
This
section
will
be
added
by
Jerome
Blondell.

1.5
Summary
of
Physical
and
Chemical
Properties
of
Imazapyr
Chemical
Name:
2­[
4,5­
dihydro­
4­
methyl­
4­(
1­
methylethyl)­
5­
oxo­
1H­
imidazol­
2­
yl]­
3­
pyridinecarboxylic
acid
Common
Name:
Imazapyr
Chemical
Type:
Herbicide
PC
Code
Number:
128821
CAS
Registry
No.:
81334­
34­
1
Empirical
Formula:
C
13
H
15
N
3
O
3
Molecular
Weight:
261.3
The
following
data
for
imazapyr
were
taken
from
product
chemistry
data
supplied
by
BASF:

Vapor
Pressure:
<
2
x
10­
7
mm
Hg
at
20
°
C
Water
Solubility:
1.11
g/
100
mL
at
25
°
C
Octanol/
Water
Partition
Coefficient:
1.3
at
22
°
C
Melting
Point:
169­
173
°
C
Density:
0.35
g/
mL
Imazapyr
is
a
solid
at
room
temperature
with
a
low
vapor
pressure;
thus,
any
losses
due
to
volatilization/
sublimation
are
expected
to
be
minimal.

1.6
Summary
of
Use
Patterns
and
Formulations
1.6.1
End­
Use
Products
Imazapyr
is
an
herbicide
used
in
the
United
States
in
agricultural,
commercial,
and
residential
settings.
Imazapyr
is
formulated
as
a
liquid,
a
wettable
powder
(
including
water
soluble
bags),
and
a
granular.

1.6.2
Registered
Use
Categories
and
Sites
An
analysis
of
the
current
labeling
and
available
use
information
was
completed
by
HED.
Imazapyr
is
registered
for
use
in
a
variety
of
occupational
and
residential
scenarios
(
see
Tables
2
through
4)
and
thus
both
occupational
and
residential
populations
could
be
potentially
exposed
while
making
imazapyr
applications.
It
is
also
possible
for
occupational
and
residential
populations
to
be
exposed
to
imazapyr
during
postapplication
time
periods.
Page
11
of
63
Table
2:
Summary
of
Maximum
Application
Rates
for
Registered
Imazapyr
Agricultural
Uses
Crop
Type/
Use
Site
Target
of
Application
Application
Equipment
Maximum
Application
Rate
clearfield
corn
hybrids
foliage
backpack,
low­
pressure,
handgun,
groundboom,
aerial
0.014lb
ae/
A
Table
3:
Summary
of
Maximum
Application
Rates
for
Registered
Imazapyr
Commercial
Uses
Crop
Type/
Use
Site
Target
of
Application
Application
Equipment
Maximum
Application
Rate
non­
crop
areas
(
including
highway
rights­
of­
way,
turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,
commercial/
industrial
areas)
grasses,
weeds,
paved
surfaces
aerial,
groundboom,
low­
pressure
handwand,
high­
pressure
handwand,
handgun,
rights­
ofway
sprayer,
backpack
1.5
lb
ae/
A
(
liquid)

non­
crop
areas
(
including
highway
rights­
of­
way,
turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,
commercial/
industrial
areas)
grasses,
weeds
aerial,
tractor
drawn
spreader,
push­
type
spreader,
backpack
spreader
1.5
lb
ae/
A
(
granular)

broadcast
application
to
aquatic
areas
or
draw
down
area
aquatic
vegetation
aerial,
boat,
handgun,
low­
pressure
handwand
1.5
lb
ae/
A
trees
brush,
trees
aerial,
groundboom,
handgun,
rights­
of­
way
sprayer
1.25
lb
ae/
A
areas
grazed
or
cut
for
hay
saltcedar
aerial,
groundboom,
low­
pressure
handwand
1.0
lb
ae/
A
trees
brush,
trees
EXJECT
capsule
injection
equipment
­
­

Table
4:
Summary
of
Maximum
Application
Rates
for
Registered
Imazapyr
Residential
Uses
Crop
Type/
Use
Site
Target
of
Application
Application
Equipment
Maximum
Application
Rate
driveways,
parking
areas,
brick
walls,
gravel
pathways,
patios,
along
sidewalks
and
bare
ground
grasses,
weeds
low­
pressure
handwand,
sprinkling
can
0.19
lb
ae/
1,000
sq
ft
Page
12
of
63
1.6.3
Application
Methods
Imazapyr
is
applied
with
several
types
of
application
equipment
 
the
major
wide­
area
methods
are
aerial,
groundboom
sprayer,
boat,
rights­
of­
way
sprayer,
and
tractor­
drawn
spreader.
Applications
to
smaller
areas
may
be
made
with
handheld
equipment,
including
low­
pressure
handwand
sprayers,
backpack
sprayers,
sprinkling
cans,
tree
injectors
and
handgun
sprayers.

2.0
Occupational
Exposures
and
Risks
There
is
a
potential
for
exposure
to
imazapyr
in
occupational
scenarios
from
handling
imazapyr
products
during
the
application
process
(
i.
e.,
mixer/
loaders,
applicators,
flaggers,
and
mixer/
loader/
applicators)
and
a
potential
for
postapplication
worker
exposure
from
entering
into
areas
previously
treated
with
imazapyr.
As
a
result,
risk
assessments
have
been
completed
for
occupational
handler
scenarios
as
well
as
occupational
postapplication
scenarios.

2.1
Occupational
Handler
Exposures
and
Risks
HED
uses
the
term
"
handlers"
to
describe
those
individuals
who
are
involved
in
the
pesticide
application
process.
HED
believes
that
there
are
distinct
job
functions
or
tasks
related
to
applications
and
that
exposures
can
vary
depending
on
the
specifics
of
each
task.
Job
requirements
(
e.
g.,
amount
of
chemical
to
be
used
in
an
application),
the
kinds
of
equipment
used,
the
target
being
treated,
and
the
level
of
protection
used
by
a
handler
can
cause
exposure
levels
to
differ
in
a
manner
specific
to
each
application
event.

Exposure
scenarios
can
be
thought
of
as
ways
of
categorizing
the
kinds
of
exposures
that
occur
related
to
the
use
of
a
chemical.
The
use
of
scenarios
as
a
basis
for
exposure
assessment
is
very
common
as
described
in
the
U.
S.
EPA
Guidelines
For
Exposure
Assessment
(
U.
S.
EPA;
Federal
Register
Volume
57,
Number
104;
May
29,
1992).
Information
from
the
current
labels;
use
and
usage
information;
toxicology
data;
and
exposure
data
were
all
key
components
in
developing
the
exposure
scenarios.

The
first
step
in
the
handler
risk
assessment
process
is
to
identify
the
kinds
of
individuals
that
are
likely
to
be
exposed
to
imazapyr
during
the
application
process.
In
order
to
do
this
in
a
consistent
manner,
HED
has
developed
a
series
of
general
descriptions
for
tasks
that
are
associated
with
pesticide
applications.
Tasks
associated
with
occupational
pesticide
use
(
i.
e.,
for
"
handlers")
can
generally
be
categorized
using
one
of
the
following
terms:

C
Mixers
and/
or
Loaders:
these
individuals
perform
tasks
in
preparation
for
an
application.
For
example,
prior
to
application,
mixer/
loaders
would
mix
the
imazapyr
and
load
it
into
the
holding
tank
of
the
airplane
or
groundboom
sprayers.

C
Applicators:
these
individuals
operate
application
equipment
during
the
release
of
a
pesticide
product
into
the
environment.
These
individuals
can
make
applications
using
Page
13
of
63
equipment
such
as
airplanes
or
groundboom
sprayers.

C
Mixer/
Loader/
Applicators
and
or
Loader/
Applicators:
these
individuals
are
involved
in
the
entire
pesticide
application
process
(
i.
e.,
they
do
all
job
functions
related
to
a
pesticide
application
event).
These
individuals
would
transfer
imazapyr
into
the
application
equipment
and
then
also
apply
it.

C
Occupational
Flaggers:
these
individuals
guide
aerial
applicators
during
the
release
of
a
pesticide
product
onto
an
intended
target.

Next,
assessors
must
understand
how
exposures
to
imazapyr
occur
(
i.
e.,
frequency
and
duration)
and
how
the
patterns
of
these
occurrences
can
cause
the
effects
of
the
chemical
to
differ
(
referred
to
as
dose
response).
Wherever
possible,
use
and
usage
data
determine
the
appropriateness
of
certain
types
of
risk
assessments.
Other
parameters
are
also
defined
from
use
and
usage
data
such
as
application
rates
and
application
frequency.
HED
always
completes
non­
cancer
risk
assessments
using
maximum
application
rates
for
each
scenario
because
what
is
possible
under
the
label
(
the
legal
means
of
controlling
pesticide
use)
must
be
evaluated
in
order
to
ensure
there
are
no
concerns
for
each
specific
use.

HED
believes
that
occupational
imazapyr
exposures
can
occur
over
a
single
day
or
up
to
weeks
at
a
time
for
many
use­
patterns
and
intermittent
exposures
over
several
weeks
are
also
anticipated.
Custom
or
commercial
applicators
may
apply
imazapyr
over
a
period
of
weeks
completing
applications
for
a
number
of
different
clients.
HED
classifies
exposures
up
to
30
days
as
shortterm
and
exposures
greater
than
30
days
up
to
several
months
as
intermediate­
term.
HED
completes
both
short­
and
intermediate­
term
assessments
for
occupational
scenarios
in
essentially
all
cases,
because
these
kinds
of
exposures
are
likely
and
acceptable
use/
usage
data
are
not
available
to
justify
deleting
intermediate­
term
scenarios.
Long­
term
handler
exposures
are
not
expected
to
occur
for
imazapyr.
The
same
toxicological
endpoint
of
concern
(
from
an
oral
study)
was
selected
for
short­
and
intermediate­
term
dermal
and
inhalation
imazapyr
exposures,
therefore
the
risk
results
for
both
durations
of
exposure
are
numerically
identical.

Occupational
handler
exposure
assessments
are
completed
by
HED
using
different
levels
of
personal
protection.
HED
typically
evaluates
all
exposures
with
a
tiered
approach.
The
lowest
tier
is
represented
by
the
baseline
exposure
scenario
(
i.
e.,
long­
sleeve
shirt,
long
pants,
shoes,
and
socks)
followed
by
increasing
the
levels
of
personal
protective
equipment
or
PPE
(
e.
g.,
gloves,
double­
layer
body
protection,
and
respirators)
and
engineering
controls
(
e.
g.,
enclosed
cabs
and
closed
mixing/
loading
systems).
This
approach
is
always
used
by
HED
in
order
to
be
able
to
define
label
language
using
a
risk­
based
approach.
In
addition,
the
minimal
level
of
adequate
protection
for
a
chemical
is
generally
considered
by
HED
to
be
the
most
practical
option
for
risk
reduction
(
i.
e.,
over­
burdensome
risk
mitigation
measures
are
not
considered
a
practical
alternative).
Page
14
of
63
2.1.1
Data
and
Assumptions
For
Handler
Exposure
Scenarios
2.1.1.1
Assumptions
for
Handler
Exposure
Scenarios
A
series
of
assumptions
and
exposure
factors
served
as
the
basis
for
completing
the
occupational
handler
risk
assessments.
Each
assumption
and
factor
is
detailed
below
on
an
individual
basis.
The
assumptions
and
factors
used
in
the
risk
calculations
include:

C
HED
has
patterned
this
risk
assessment
on
a
series
of
likely
representative
scenarios
that
are
believed
by
HED
to
represent
the
vast
majority
of
imazapyr
uses.

C
Occupational
handler
exposure
estimates
were
based
on
surrogate
data
from:
the
Pesticide
Handlers
Exposure
Database
(
PHED),
Outdoor
Residential
Exposure
Task
Force
(
ORETF),
and
proprietary
studies.

C
Average
body
weight
of
an
adult
handler
is
70
kg
because
the
toxicity
endpoint
values
used
for
the
assessments
are
appropriate
for
average
adult
body
weight
representing
the
general
population.

C
Generic
protection
factors
(
PFs)
were
used
to
calculate
exposures
when
data
were
not
available.
For
example,
an
80
percent
protection
factor
was
assumed
for
the
use
of
a
quarter­
face
cup­
style
respirator
equipped
with
dust/
mist
filter.

C
Exposure
factors
used
to
calculate
daily
exposures
to
handlers
are
based
on
applicable
data
if
available.
For
lack
of
appropriate
data,
values
from
a
scenario
deemed
similar
enough
by
the
assessor
might
be
used.
As
an
example,
for
imazapyr
handler
exposures,
ORETF
data
for
hose­
end
sprayer
equipment
were
used
to
assess
sprinkling
can
applications.
The
nature
of
these
application
methods
are
believed
to
be
similar
enough
to
bridge
the
data.

C
For
non­
cancer
assessments,
HED
assumes
the
maximum
application
rates
allowed
by
labels
in
its
risk
assessments
(
see
Tables
2
through
4).

C
The
average
occupational
workday
is
assumed
to
be
8
hours.

C
The
daily
areas
treated
were
defined
for
each
handler
scenario
(
in
appropriate
units)
by
determining
the
amount
that
can
be
reasonably
treated
in
a
single
day
(
e.
g.
acres,
square
feet,
or
gallons
per
day).
When
possible,
the
assumptions
for
daily
areas
treated
is
taken
from
the
HED
ExpoSAC
SOP
#
9:
Standard
Values
for
Daily
Acres
Treated
in
Agriculture
which
was
completed
on
July
5,
2000.
[
Note:
No
standard
values
are
available
for
the
tree
injection
scenario.]

S
Aerial
spray
and
granular
applications:
400
acres
for
aquatic
sites*,
350
acres
for
corn
(
since
it
is
applied
to
Clearfield
corn
hybirds
only),
forest
sites,
and
areas
Page
15
of
63
grazed
or
cut
for
hay
and
a
rangefinder
of
100
­
350
acres
for
aerial
applications
to
non­
crop
areas;

S
Groundboom:
80
acres
for
corn
(
since
it
is
applied
to
Clearfield
corn
hybirds
only),
forest
sites,
areas
grazed
or
cut
for
hay,
and
non­
crop
areas;

S
Rights
of
Way
Spreader:
80
acres
for
forest
sites
and
non­
crop
areas;

S
Tractor­
Drawn
Spreader:
80
acres
for
non­
crop
areas;

S
Boat
Applications:
10
acres
for
aquatic
sites*;

S
Flaggers:
350
acres
for
all
aerial
use
sites;

S
Handgun:
10
acres
for
aquatic
sites*,
5
acres
for
forest
sites
and
non­
crop
areas;

S
Low
Pressure
Handwand
Sprayer:
5
acres
for
non­
crop
areas;

S
Backpack
Sprayer:
5
acres
for
aquatic
sites*;

S
High
Pressure/
Volume
Handwand:
5
acres
for
non­
crop
areas;

S
Push
Type
Granular
Spreader:
5
acres
for
non­
crop
areas;

S
Bellygrinder:
5
acres
for
non­
crop
areas;
and
S
Backpack
Granular
Spreader:
rangefinder
of
5­
10
acres
for
non­
crop
areas.

*
Further
descriptions
of
these
assumptions
can
be
found
in
Imazapyr
in/
on
Rangeland
and
Aquatic
Sites.
Health
Effects
Division
(
HED)
Risk
Assessment.
Dana
Vogel.
DP
Barcode
DP291393.
July
17,
2003.

2.1.1.2
Exposure
Data
for
Handler
Exposure
Scenarios
No
chemical
specific
information
was
available
for
imazapyr
handler
exposure
assessments,
all
analyses
were
completed
using
acceptable
surrogate
exposure
data
for
the
scenario
in
question.

HED
uses
a
concept
known
as
unit
exposure
as
the
basis
for
the
scenarios
used
to
assess
handler
exposures
to
pesticides.
Unit
exposures
numerically
represent
the
exposures
one
would
receive
related
to
an
application.
They
are
generally
presented
as
mg
active
ingredient
exposure/
pounds
of
handled
(
mg
ai/
lb).
HED
has
developed
different
unit
exposures
for
different
types
of
application
equipment;
job
functions;
and
levels
of
protection.
The
unit
exposure
concept
has
been
established
in
the
scientific
literature
and
also
through
various
exposure
monitoring
guidelines
published
by
the
U.
S.
EPA
and
international
organizations
such
as
Health
Canada
and
OECD
(
Organization
For
Economic
Cooperation
and
Development).

Pesticide
Handler
Exposure
Database
(
PHED)
Version
1.1
(
August
1998):
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
exposures
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)
Page
16
of
63
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
exposures
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
exposures
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
exposures
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
Appendix
A,
Table
A1.
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
exposures
for
many
occupational
scenarios
that
can
be
utilized
to
ensure
consistency
in
exposure
assessments.
Unit
exposures
are
used
which
represent
different
levels
of
personal
protection
as
described
above.
Protection
factors
were
used
to
calculate
unit
exposures
for
varying
levels
of
personal
protection
if
data
were
not
available.

ORETF
Handler
Studies
(
MRID
449722­
01):
A
report
was
submitted
by
the
ORETF
(
Outdoor
Residential
Exposure
Task
Force)
that
presented
data
in
which
the
application
of
various
products
used
on
turf
by
homeowners
and
lawncare
operators
(
LCOs)
was
monitored.
All
of
the
data
submitted
in
this
report
were
completed
in
a
series
of
studies.
The
study
that
monitored
LCO
exposure
scenarios
using
a
push
type
granular
spreader
(
ORETF
Study
OMA001)
is
summarized
below
as
is
the
study
that
monitored
LCO
exposure
scenarios
using
a
low
pressure,
high
volume
turf
handgun
(
ORETF
Study
OMA002).

LCO
Push
Type
Granular
Spreader:
A
loader/
applicator
study
was
performed
by
the
ORETF
using
Dacthal
(
active
ingredient
DCPA,
dimethyl
tetrachloroterephthalate)
as
a
surrogate
compound
to
determine
"
generic"
exposures
of
lawn
care
operators
(
LCOs)
applying
a
granular
Page
17
of
63
pesticide
formulation
to
residential
lawns.
Surrogate
chemicals
were
chosen
by
the
Task
Force
for
their
representativeness
based
on
physical
chemical
properties
and
other
factors.
Dacthal,
which
was
the
surrogate
chemical
used
for
the
granular
spreader
and
low­
pressure
hand
gun
sprayer
studies,
has
a
molecular
weight
of
331.97
and
a
vapor
pressure
of
1.6
x
10­
6
mm
Hg,
and
is
believed
to
be
an
appropriate
surrogate
for
many
relatively
nonvolatile
pesticides.
The
study
was
designed
to
simulate
a
typical
work
day
for
a
LCO
applying
granular
pesticide
formulation
to
home
lawns.
Each
LCO
replicate
loaded
and
applied
approximately
3.3
lbs
ai
(
360
lbs
formulated
product)
over
a
period
of
about
4
hours
to
15
simulated
residential
lawns
(
6480
ft2
each)
with
a
rotary
type
spreader.
The
average
industry
application
rate
of
2
lbs
ai/
acre
was
simulated
(
actual
rate
achieved
was
about
1.9
lbs
ai/
acre).
The
monitoring
period
included
simulated
driving,
placing
the
spreader
onto
and
off
of
the
truck,
carrying
and
loading
the
formulation
in
the
spreader,
and
the
actual
application.
Incidental
activities
such
as
repairs,
cleaning
up
spills,
and
disposing
of
empty
bags
were
monitored.

A
total
of
40
replicates
(
individual
test
subjects)
were
monitored
using
passive
dosimetry
(
inner
and
outer
whole
body
dosimeters,
hand
washes,
face/
neck
wipes,
and
personal
inhalation
monitors
with
OVS
tubes).
Inhalation
exposure
was
calculated
using
an
assumed
respiratory
rate
of
17
Lpm
(
1
m3/
hr)
for
light
work
(
NAFTA,
1999),
the
actual
sampling
time
for
each
individual,
and
the
pump
flow
rate.
All
results
were
normalized
for
lb
a.
i.
handled.
Twelve
professional
lawn
care
operators
(
LCO)
participated
in
the
study.
Ten
individuals
per
day
(
20
per
site)
were
monitored
over
4
days
at
2
different
sod
farms
near
Columbus,
Ohio.
Each
replicate
consisted
of
a
LCO
loading
and
applying
approximately
3.3
lbs
ai
/
360
lbs
formulated
product
(
1.5
kg
ai/
163
kg
formulated
product)
to
15
simulated
residential
lawns,
for
an
approximate
total
duration
of
4
hours
and
total
area
of
2.2
acres
(
0.9
ha).
Twenty
test
subjects
wore
chemical­
resistant
gloves
during
all
loading
and
application
activities
and
moving
the
spreader
on
and
off
the
truck,
then
removed
and
place
the
gloves
in
the
truck
during
simulated
driving
time.
The
other
twenty
test
subjects
did
not
wear
gloves
during
any
activity.
Each
test
subject
wore
long
sleeve
cotton
shirts
and
pants
over
one­
piece
cotton
inner
dosimeters.
Both
outer
and
inner
dosimeters
were
analyzed
to
estimate
potential
exposure
for
a
number
of
clothing
scenarios.

Nearly
all
samples
(
for
every
body
part
and
for
inhalation)
were
above
the
level
of
quantitation
(
LOQ)
for
dacthal
(
the
level
of
detection,
or
LOD
was
not
reported).
Where
results
were
less
than
the
reported
LOQ,
½
LOQ
value
was
used
for
calculations,
and
no
recovery
corrections
were
applied.
The
overall
laboratory
recoveries
(
83­
101%)
and
field
recoveries
(
73­
98%)
were
within
guideline
parameters.
An
data
average
recovery
greater
than
90%
does
not
require
correction;
all
data
sets
beyond
this
criterion
were
corrected
by
PMRA
reviewers
for
the
recovery
of
the
nearest
field
fortification
level.
The
HED
Exposure
SAC
reviewed
the
data
and
recommends
using
the
hand
replicates
with
the
corresponding
subject's
dermal
body
replicates,
rather
than
combining
them
in
an
attempt
to
increase
statistical
power
(
the
latter
method
was
favored
by
PMRA).
Keeping
the
two
sets
of
data
separate
(
20
gloved,
20
ungloved)
is
considered
to
be
a
better
representation
of
an
individual's
"
total"
exposure.
Therefore
the
OMA001
data
may
be
classified
as
"
A/
B"
quality
and
of
"
high
confidence".
Page
18
of
63
This
study
is
of
sufficient
quality
and
scope
to
make
it
broadly
applicable
for
use
as
a
surrogate
chemical
in
estimating
LCO
handler
exposures.
The
unit
exposure
value
from
the
long
sleeves
and
long
pants
scenario
is
lower
than
the
unit
exposure
reported
in
the
current
PHED
tables.
The
inhalation
unit
exposures
agree
very
closely
with
the
current
PHED
values.
The
current
PHED
study
contains
"
C"
(
or
low)
grade
data
and
therefore
will
not
be
combined
with
the
ORETF
study.
The
unit
exposure
values
can
be
seen
in
Table
5.

Table
5:
Unit
Exposures
Obtained
From
ORETF
LCO
Push
Type
Granular
Spreader
(
MRID
449722­
01)

Application
Method
Total
Dermal
Unit
Exposure
(
mg/
lb
ai)
Inhalation
Unit
Exposure
(
µ
g/
lb
ai)
1
Single
Layer,
No
Gloves
Single
Layer,
Gloves
Double
Layer,
Gloves
2
LCO
Push
Type
Spreader
Mixer/
Loader/
Applicator
Granular
3
0.35
0.22
0.11
7.3
1Air
concentration
(
mg/
m3/
lb
ai)
calculated
using
NAFTA
`
99
standard
breathing
rate
of
17
lpm
(
1
m3/
hr)
2Exposure
calculated
using
OPP/
HED
50%
protection
factor
(
PF)
for
cotton
coveralls
on
torso,
arms,
legs.
3All
commercial
handlers
wore
long
pants,
long­
sleeved
shirt,
nitrile
gloves
and
shoes.

LCO
Handgun
Sprayer:
A
mixer/
loader/
applicator
study
was
performed
by
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
using
Dacthal
as
a
surrogate
compound
to
determine
"
generic"
exposures
to
individuals
applying
a
pesticide
to
turf
with
a
low­
pressure
"
nozzle
gun"
or
"
hand
gun"
sprayer.
Dermal
and
inhalation
exposures
were
estimated
using
whole­
body
passive
dosimeters
and
breathing­
zone
air
samples
on
OVS
tubes
(
biological
monitoring
data
were
not
collected).
Inhalation
exposure
was
calculated
using
an
assumed
respiratory
rate
of
17
Lpm
for
light
work
(
NAFTA,
1999),
the
actual
sampling
time
for
each
individual,
and
the
pump
flow
rate.
All
results
were
normalized
for
lb
a.
i.
handled.
A
total
of
90
replicates
were
monitored
using
17
test
subjects.
Four
different
formulations
of
dacthal
[
75%
wettable
powder/
WP
(
packaged
in
4lb
and
24
lb
bags),
75%
wettable
powder
in
water
soluble
bags/
WSB
(
3
lb
bag),
75%
water
dispersible
granules/
WDG
(
2
lb
bag)
and
55%
liquid
flowable/
FL
(
2.5
Gal
container)]
were
mixed,
loaded,
and/
or
applied
by
five
different
LCOs
to
actual
residential
lawns
at
each
site
in
three
different
locations
(
Ohio,
Maryland,
and
Georgia),
for
a
total
of
fifteen
replicates
per
formulation.
An
additional
ten
replicates
at
each
site
were
monitored
while
they
performed
spray
application
only
(
using
75%
wettable
powder
formulation).

A
target
application
rate
of
2
lb
ai/
acre
was
used
for
all
replicates
(
actual
rate
achieved
was
about
2.2
lbs
ai/
acre).
Each
replicate
treated
a
varying
number
of
actual
client
lawns
to
attain
a
"
representative"
target
of
2.5
acres
(
1
hectare)
of
turf.
This
is
approximately
one­
half
the
5
acres
typically
used
in
HED
exposure
estimates
for
LCOs
applying
pesticides
with
a
hand
gun
controlled
pressurized
system
for
an
8­
hour
work
day.
The
application
times
varied
considerably
between
replicate
because
of
the
study
design,
but
total
sampling
time
was
meant
to
simulate
a
full
day
of
spraying
customer
lawns.
The
exposure
periods
averaged
five
hours
twenty­
one
minutes,
five
hours
thirty­
nine
minutes,
and
six
hours
twenty­
four
minutes,
in
Ohio,
Maryland
and
Page
19
of
63
Georgia,
respectively.
Average
time
spent
actually
spraying
at
all
sites
was
about
two
hours.
All
mixing,
loading,
application,
adjusting,
calibrating,
and
spill
clean
up
procedures
were
monitored,
except
for
typical
end­
of­
day
clean­
up
activities
(
e.
g.
rinsing
of
spray
tank,
etc.).

Dermal
exposure
was
measured
using
inner
and
outer
whole
body
dosimeters,
hand
washes,
face/
neck
washes,
and
personal
air
monitoring
devices.
All
test
subjects
wore
one­
piece,
100%
cotton
inner
dosimeters
beneath
100%
cotton
long­
sleeved
shirt
and
long
pants,
rubber
boots
and
nitrile
gloves.
Gloves
are
typically
worn
by
most
LCOs,
and
required
by
many
pesticide
labels
for
mixing
and
loading.
Overall,
residues
were
highest
on
the
upper
and
lower
leg
portions
of
the
dosimeters
In
general,
concurrent
laboratory
fortifications
produced
mean
recoveries
in
the
range
of
78­
120%,
with
the
exception
of
OVS
sorbent
tube
sections
which
produced
mean
recoveries
as
low
as
65.8%.
With
the
exception
of
the
lowest
OVS
tube
spike
level
on
the
14th
day,
the
variation
in
mean
field
recoveries
between
sampling
days
did
not
exceed
a
coefficient
of
variation
(
CV)
of
25%;
the
same
was
true
for
mean
recoveries
for
each
of
the
three
general
sites
(
Ohio,
Maryland,
and
Georgia).
Adjustment
for
recoveries
from
field
fortifications
were
performed
on
each
dosimeter
section
or
sample
matrix
for
each
study
participant,
using
the
mean
recovery
for
the
closest
field
spike
level
for
each
matrix
and
correcting
the
value
to
100%.
The
data
for
this
study
are
for
the
most
part
"
B"
or
better,
and
the
study
meets
the
criterion
for
minimum
replicates
(
15
or
more
per
body
part).
Therefore
OMA002
may
be
ranked
"
high
confidence"
data.
Most
residues
were
above
the
limit
of
quantitation.
Where
results
were
less
than
the
reported
LOQ,
½
LOQ
value
was
used
for
calculations,
and
no
recovery
corrections
were
applied.

The
values
for
dermal
and
inhalation
unit
exposures
in
the
PHED
are
based
on
a
single
applicator
study
and
are
of
C­
grade.
The
unit
exposures
in
PHED
are
for
a
single
layer
of
clothing
with
gloves
only,
and
are
in
the
range
of
the
values
in
the
ORETF
data
for
this
same
scenario
and
clothing.
The
mean
inhalation
value
is
nearly
the
same
in
both
studies.
This
study
is
of
sufficient
quality
and
scope
to
make
it
broadly
applicable
for
use
as
a
surrogate
chemical
in
estimating
LCO
exposures.
The
PHED
v.
1.1
study
only
contains
applicator
data
and
does
not
consider
LCOs
who
mix
their
own
pesticide
each
day.
There
were
only
14
replicates
in
the
PHED
study,
all
of
whom
wore
gloves,
and
the
data
were
of
lower
quality.
The
unit
exposure
values
can
be
seen
in
Table
6.
Page
20
of
63
Table
6:
Unit
Exposures
Obtained
From
ORETF
LCO
Handgun
Studies
(
MRID
449722­
01)

Application
Method
Total
Dermal
Unit
Exposure
(
mg/
lb
ai)
Inhalation
Unit
Exposure
(
µ
g/
lb
ai)
1
Single
Layer,
No
Gloves
Single
Layer,
Gloves
Double
Layer,
Gloves
2
LCO
Handgun
Spray
Mixer/
Loader/
Applicator
Liquid
Flowable3
No
Data
0.45
0.245
1.8
LCO
Handgun
Spray
Mixer/
Loader/
Applicator
Wettable
Powder
3
No
Data
0.80
0.43
64
LCO
Handgun
Spray
Mixer/
Loader/
Applicator
Wettable
Powder
in
Water
Soluble
Bags
3
No
Data
0.64
0.37
7.2
1Air
concentration
(
mg/
m3/
lb
ai)
calculated
using
NAFTA
`
99
standard
breathing
rate
of
17
lpm
(
1
m3/
hr)
2Exposure
calculated
using
OPP/
HED
50%
protection
factor
(
PF)
for
cotton
coveralls
on
torso,
arms,
legs.
3All
commercial
handlers
wore
long
pants,
long­
sleeved
shirt,
nitrile
gloves
and
shoes.

Proprietary
Studies
Two
proprietary
studies
were
used
to
obtain
unit
exposures
for
handlers
applying
granular
formulations
via
granular
backpack
spreaders.
The
studies
are
summarized
below:

EPA
MRID
451672­
01
(
Temik
10G
granular
backpack
spreader
study):
Exposure
during
the
application
of
a
granular
formulation
of
the
insecticide,
aldicarb
(
i.
e.,
Temik
10G),
was
monitored
during
granular
backpack
application
to
bananas
for
control
of
insects,
mites,
and
nematodes.

A
total
of
12
mixer/
loader/
applicator
events
during
granular
backpack
(
i.
e.,
a
specialized
device
manufactured
by
Swissmex
Rapid)
application
to
bananas
were
monitored
during
August
of
1998
on
the
island
of
Martinique
which
is
in
the
French
West
Indies.
Weather
was
typical
of
the
application
season
in
that
it
was
hot,
humid,
and
rainy
at
points.
Monitoring
was
completed
using
whole
body
dosimeters,
handwashes,
facial
wipes,
and
personal
sampling
pumps
equipped
with
XAD
resin/
filter
combination
samplers.
Temik
10G
was
supplied
in
22
pound
boxes
which
was
loaded
directly
into
the
backpack
devices
(
i.
e.,
4
to
8
boxes
were
used
per
replicate).
The
application
rate
for
aldicarb
used
in
this
study
is
20
grams
of
Temik
10G
(
i.
e.,
2
grams
ai/
plant)
which
is
equivalent
to
about
3.56
lb
ai/
acre
at
approximately
2000
plants
per
acre.
The
numbers
of
acres
treated
ranged
from
approximately
2.5
to
5
acres.
The
pounds
of
active
ingredient
handled
ranged
from
8.8
up
to
17.6
per
replicate.
Each
applicator
wore
the
whole
body
dosimeters
covered
by
a
cotton
coverall,
Tyvek
gloves
supplied
with
the
Temik
10G
formulation,
and
an
apron
on
their
backs
between
their
backs
and
the
backpack
applicator.
The
Tyvek
gloves
were
changed
with
each
box
of
Temik
10G
used.
In
many
instances,
the
gloves
were
compromised
because
they
were
ripped.
In
one
case,
the
gloves
filled
with
rainwater.
In
many
other
cases,
when
the
whole
body
dosimeters
were
removed,
they
were
found
to
be
wet
and
muddy.
Page
21
of
63
Analysis
of
aldicarb
and
its
sulfoxide
and
sulfone
degradates
was
completed.
The
residue
levels
were
added
together
to
obtain
total
exposure
levels.
The
limits
of
quantification
(
LOQ)
were
1.0
µ
g
per
sample
for
the
whole­
body
dosimeters
and
handwashes
(
600
mL
volume).
The
LOQ
for
the
facial
wipes
was
0.10
µ
g
per
sample
and
0.050
0.10
µ
g
per
sample
for
the
air
filters.
Field
and
laboratory
recovery
data
were
generated
for
all
media
for
all
residues
measured
(
i.
e.,
parent
and
metabolites).
Field
recovery
data
were
generated
in
a
manner
that
addressed
field
sampling,
field
storage,
transport,
laboratory
storage,
and
analysis.
Residues
were
corrected
for
the
overall
average
field
recovery
for
each
residue/
matrix
combination.
Generally,
recovery
was
adequate
for
all
media/
residue
combinations.
If
the
PHED
grading
criteria
are
applied
all
residue/
matrix
combinations
(
except
facial
wipes
with
sulfone
residues)
have
at
least
grade
"
B"
data
and
in
many
cases
the
data
meet
the
grade
"
A"
criteria.
The
grade
"
B"
criteria
require
laboratory
recovery
data
with
an
average
of
at
least
80
percent
and
a
coefficient
of
variation
of
25
or
less
accompanied
with
field
recoveries
that
are
at
least
50
percent
but
not
exceeding
120
percent.
The
grade
"
A"
criteria
require
laboratory
recovery
data
with
an
average
of
at
least
90
percent
and
a
coefficient
of
variation
of
15
or
less
accompanied
with
field
recoveries
that
are
at
least
70
percent
but
not
exceeding
120
percent.

Unit
exposure
values
were
calculated
using
the
data
from
the
study
and
a
commercial
spreadsheet
program.
The
exposures
that
were
calculated
were
normalized
by
the
amount
of
chemical
used,
the
duration
of
the
application
interval,
and
by
the
body
weight
of
the
individual
applicators.
For
each
calculation,
the
arithmetic
mean,
geometric
mean,
and
various
percentiles
were
calculated.
No
analyses
were
completed
with
these
data
to
ascertain
the
exact
type
of
distribution.
The
Agency
typically
uses
the
best
fit
values
from
the
Pesticide
Handlers
Exposure
Database
which
are
representations
of
the
central
tendency.
Considering
the
standard
practice,
the
Agency
will
use
the
geometric
mean
for
risk
assessment
purposes.
The
unit
exposures
are
presented
below
in
Table
7.

Table
7:
Unit
Exposures
Obtained
From
Temik
10G
Granular
Backpack
Spreader
Study
(
MRID
451672­
01)

Application
Method
Total
Dermal
Unit
Exposure
(
mg/
lb
ai)
Inhalation
Unit
Exposure
(
µ
g/
lb
ai)
1
Single
Layer,
No
Gloves
Single
Layer,
Gloves
Double
Layer,
Gloves
Granular
Backpack
Spreader
No
Data
0.1
No
Data
4.2
1Air
concentration
(
mg/
m3/
lb
ai)
calculated
using
NAFTA
`
99
standard
breathing
rate
of
17
lpm
(
1
m3/
hr)

MRID
452507­
01
(
Regent
20GR
granular
backpack
spreader
study):
A
total
of
18
mixer/
loader/
applicator
events
during
granular
backpack
(
i.
e.,
a
specialized
device
manufactured
by
Horstine
Farmery)
or
spoon
application
to
bananas
were
monitored
during
applications
on
three
different
days
in
June,
1994
on
the
same
banana
plantation
in
Cameroon.
The
18
replicates
were
distributed
over
the
3
sampling
days
as
follows:
6
spoon/
hand
applications
on
day
1;
4
spoon/
hand
applications
on
day
2;
and
8
backpack
events
on
day
3.
Weather
was
typical
of
the
application
season
in
that
it
was
hot
and
humid.
Monitoring
was
completed
using
whole
body
Page
22
of
63
dosimeters,
cotton
gloves,
cotton
caps,
and
personal
sampling
pumps
equipped
with
filters.
Regent
20GR
was
supplied
in
22
pound
boxes
which
was
loaded
directly
into
the
backpack
devices
or
buckets
for
the
spoon
applicators.
The
application
rate
for
fipronil
used
in
this
study
is
7.5
grams
of
Regent
20GR
(
i.
e.,
0.15
grams
ai/
plant)
which
is
equivalent
to
about
0.26
lb
ai/
acre
(
0.00033
lb
ai/
plant)
at
approximately
800
plants
per
acre.
The
numbers
of
acres
treated
ranged
from
approximately
0.75
to
1
acre.
The
pounds
of
active
ingredient
handled
ranged
from
about
a
quarter
to
half
a
pound
per
replicate.
Each
applicator
wore
whole
body
dosimeters
that
also
served
as
the
normal
work
clothing.
PVC
gloves
were
also
worn
over
cotton
gloves
which
served
as
the
dosimeters.
A
protection
factor
of
50
percent
was
used
by
the
Agency
to
calculate
exposure
levels
under
a
layer
of
normal
work
clothing.
Dosimeter
samples
were
segments
into
arms,
legs,
and
torso
for
analysis.

Analysis
of
fipronil
residues
was
completed
with
gas
chromatography
and
electron
capture
detection.
The
limits
of
quantification
(
LOQ)
were
9.7
µ
g
per
sample
for
all
media
used.
The
limit
of
detection
(
LOD)
varied
for
each
media.
The
LOD
for
the
cotton
gloves
was
0.5
µ
g
per
sample,
0.10
µ
g
per
sample
for
the
air
filters,
and
2.0
to
4.0
µ
g
per
sample
for
the
whole
body
dosimeters
depending
upon
the
sample
analyzed.
Field
and
laboratory
recovery
data
were
generated
for
all
media.
Field
recovery
data
were
generated
in
a
manner
that
addressed
field
sampling,
field
storage,
transport,
laboratory
storage,
and
analysis.
However,
the
laboratory
recovery
data
were
indeterminate
because
the
sample
media
could
not
be
identified
for
each
reported
result.
The
overall
recovery
values
do
appear
to
be
quantitative.
Residues
were
corrected
for
the
overall
average
field
recovery
for
each
residue/
matrix
combination.
Generally,
recovery
was
adequate
for
all
media/
residue
combinations
(
i.
e.,
all
correction
factors
were
greater
than
85
percent).
If
the
PHED
grading
criteria
are
applied
and
the
overall
laboratory
recovery
averages
are
used
all
residue/
matrix
combinations
are
considered
grade
"
A"
data.
The
grade
"
A"
criteria
require
laboratory
recovery
data
with
an
average
of
at
least
90
percent
and
a
coefficient
of
variation
of
15
or
less
accompanied
with
field
recoveries
that
are
at
least
70
percent
but
not
exceeding
120
percent.

Unit
exposure
values
were
calculated
using
the
data
from
the
study
and
a
commercial
spreadsheet
program.
The
exposures
that
were
calculated
were
normalized
by
the
amount
of
chemical
used,
the
duration
of
the
application
interval,
and
by
the
body
weight
of
the
individual
applicators
(
see
table
below).
The
values
are
based
on
a
50
percent
clothing
penetration
factor
and
are
separated
for
each
equipment
type
monitored
in
this
study.
For
each
normalization
factor,
the
arithmetic
mean,
geometric
mean,
and
various
percentiles
were
calculated.
No
analyses
were
completed
with
these
data
to
ascertain
the
exact
type
of
distribution.
The
Agency
typically
uses
the
best
fit
values
from
the
Pesticide
Handlers
Exposure
Database
which
are
representations
of
the
central
tendency.
Considering
the
standard
practice,
the
Agency
will
use
the
geometric
mean
for
risk
assessment
purposes.
The
unit
exposure
values
are
presented
below
in
Table
8.
Page
23
of
63
Table
8:
Unit
Exposures
Obtained
From
Regent
20GR
Granular
Backpack
Spreader
Study
(
MRID
451672­
01)

Application
Method
Total
Dermal
Unit
Exposure
(
mg/
lb
ai)
Inhalation
Unit
Exposure
(
µ
g/
lb
ai)
1
Single
Layer,
No
Gloves
Single
Layer,
Gloves
Double
Layer,
Gloves
Granular
Backpack
Spreader
No
Data
0.6
No
Data
44
1Air
concentration
(
mg/
m3/
lb
ai)
calculated
using
NAFTA
`
99
standard
breathing
rate
of
17
lpm
(
1
m3/
hr)

2.1.2
Imazapyr
Handler
Exposure
Scenarios
Exposure
to
pesticide
handlers
is
likely
during
the
occupational
use
of
imazapyr
based
on
the
types
of
equipment
and
techniques
that
can
potentially
be
used.
The
quantitative
exposure/
risk
assessment
developed
for
occupational
handlers
is
based
on
the
following
scenarios.
Imazapyr
dermal
and
inhalation
exposure
was
estimated
using
PHED,
ORETF,
and
proprietary
data.
[
Note:
Scenarios
denoted
with
a
"*"
could
not
be
evaluated
quantitatively
because
applicable
unit
exposure
data
are
not
available.]

Mixer/
Loaders:
(
1a)
Liquids
for
Fixed
Wing
Aerial
Applications;
(
1b)
Liquids
for
Groundboom
Applications;
(
1c)
Liquids
for
Rights
of
Way
Sprayers;
(
2a)
Dry
Flowables
for
Aerial
Applications;
(
2b)
Dry
Flowables
for
Groundboom
Applications;
(
2c)
Dry
Flowables
for
Rights
of
Way
Sprayers;
(
3a)
Granulars
for
Aerial
Applications;
(
3b)
Granulars
for
Tractor
Drawn
Spreader
Applications;

Applicators:
(
4)
Fixed
Wing
Aerial
Applications
(
Sprays);
(
5)
Fixed
Wing
Aerial
Applications
(
Granulars);
(
6)
Groundboom
Applications;
(
7)
Rights
of
Way
Applications;
(
8)
Tractor
Drawn
Spreader
Applications
(
Granulars);

Flaggers:
(
9)
Flagging
for
Aerial­
Sprays;
(
10)
Flagging
for
Aerial­
Granulars;

Mixer/
Loader/
Applicators:
(
11)
Liquids:
Low
Pressure
Handwand
Sprayer;
(
12)
Dry
Flowables:
Low
Pressure
Handwand
Sprayer;
Page
24
of
63
(
13)
Granulars:
Push
Type
Spreader
(
14)
Granulars:
Pump­
feed
Backpack
Spreader
(
15)
Granulars:
Gravity­
feed
Backpack
Spreader
(
16)
Liquid:
Handgun
Sprayer;
(
17)
Dry
Flowables:
Handgun
Sprayer;
(
18)
Water
Soluble
Bags:
Handgun
Sprayer;
(
19)
Liquid:
Backpack
Sprayer;
and
(
20)
Liquid:
Tree
Injection
Equipment*.

2.1.3
Non­
cancer
Imazapyr
Handler
Exposure
and
Assessment
The
occupational
handler
exposure
and
non­
cancer
risk
calculations
are
presented
in
this
section.

2.1.3.1
Non­
cancer
Imazapyr
Handler
Exposure
and
Risk
Calculations
Non­
cancer
risks
were
calculated
using
the
Margin
of
Exposure
(
MOE)
which
is
a
ratio
of
the
toxicological
endpoint
of
concern
to
the
daily
dose.
Daily
dose
values
are
calculated
by
first
calculating
exposures
by
considering
application
parameters
(
i.
e.,
rate
and
area
treated)
along
with
unit
exposures.
Exposures
are
then
normalized
by
body
weight
and
adjusted
for
absorption
factors
as
appropriate
to
calculate
dose
levels.

Daily
Exposure:
The
daily
exposure
and
daily
dose
to
handlers
were
calculated
as
described
below.
The
first
step
was
to
calculate
daily
exposure
(
dermal
or
inhalation)
using
the
following
formula:

Where:

Daily
Exposure
=
Amount
(
mg
ai/
day)
deposited
on
the
surface
of
the
skin
that
is
available
for
dermal
absorption
or
amount
inhaled
that
is
available
for
inhalation
absorption;
Unit
Exposure
=
Unit
exposures
(
mg
ai/
lb
ai)
derived
from
August
1998
PHED
data,
from
ORETF
data,
or
from
proprietary
data;
Application
Rate
=
Normalized
application
rate
based
on
a
logical
unit
treatment,
such
as
acres,
square
feet,
or
gallons.
Maximum
values
are
generally
used
(
lb
ai/
A,
lb
ai/
sq
ft,
lb
ai/
gal);
and
Daily
Area
Treated
=
Normalized
application
area
based
on
a
logical
unit
treatment
such
as
acres
(
A/
day),
square
feet
(
sq
ft/
day),
or
gallons
per
day
(
gal/
day).

Daily
Dose:
Daily
dose
(
inhalation
or
dermal)
was
calculated
by
normalizing
the
daily
dermal
or
inhalation
exposure
value
by
body
weight
and
accounting
for
dermal
or
inhalation
absorption.
For
adult
handlers
using
imazapyr,
an
average
body
weight
of
70
kilograms
was
used
for
all
exposure
scenarios.
Since
the
dermal
toxicological
endpoint
of
concern
are
based
on
an
oral
study,
a
dermal
absorption
factor
is
needed
for
dermal
dose
calculations.
However,
since
no
data
about
dermal
Page
25
of
63
absorption
are
available,
a
default
value
of
100
percent
dermal
absorption
is
used.
Since
the
inhalation
toxicological
endpoint
of
concern
are
based
on
an
oral
study,
an
inhalation
absorption
factor
is
needed
for
inhalation
dose
calculations.
However,
since
no
data
about
inhalation
absorption
are
available,
a
default
value
of
100
percent
inhalation
absorption
is
used.
Daily
dose
was
calculated
using
the
following
formula:

Where:

Average
Daily
Dose
=
Absorbed
dose
received
from
exposure
to
a
pesticide
in
a
given
scenario
(
mg
pesticide
active
ingredient/
kg
body
weight/
day);
Daily
Exposure
=
Amount
(
mg
ai/
day)
deposited
on
the
surface
of
the
skin
that
is
available
for
dermal
absorption
or
amount
inhaled
that
is
available
for
inhalation
absorption;
Absorption
Factor
=
A
measure
of
the
amount
of
chemical
that
crosses
a
biological
boundary
such
as
the
skin
or
lungs
(%
of
the
total
available
absorbed);
and
Body
Weight
=
Body
weight
determined
to
represent
the
population
of
interest
in
a
risk
assessment
(
kg).

Margins
of
Exposure:
Finally,
the
calculations
of
daily
dermal
dose
and
daily
inhalation
dose
received
by
handlers
were
then
compared
to
the
appropriate
endpoint
(
i.
e.,
NOAEL)
to
assess
the
total
risk
to
handlers
for
each
exposure
route
within
the
scenarios.
All
MOE
values
were
calculated
separately
for
dermal
and
inhalation
exposure
levels
using
the
formula
below:

Where:

MOE
=
Margin
of
exposure,
value
used
by
HED
to
represent
risk
or
how
close
a
chemical
exposure
is
to
being
a
concern
(
unitless);
ADD
=
(
Average
Daily
Dose)
or
the
amount
as
absorbed
dose
received
from
exposure
to
a
pesticide
in
a
given
scenario
(
mg
pesticide
active
ingredient/
kg
body
weight/
day);
and
NOAEL
=
Dose
level
(
mg
pesticide
active
ingredient/
kg
body
weight/
day)
in
a
toxicity
study,
where
no
observed
adverse
effects
occurred
(
NOAEL)
in
the
study.

It
is
important
to
present
risk
estimates
for
each
route
of
exposure
(
i.
e.,
dermal
or
inhalation)
in
each
scenario
because
it
makes
determining
appropriate
risk
mitigation
measures
easier.
For
example,
if
overall
risks
are
driven
by
dermal
exposures
and
not
inhalation,
it
is
inadvisable
to
require
respirators
even
though
they
may
marginally
reduce
overall
risks.
Page
26
of
63
A
total
MOE
was
calculated
for
imazapyr
because
common
toxicity
endpoints
(
skeletal
muscle
effects)
were
used
to
calculate
dermal
and
inhalation
risks
for
each
exposure
duration.
The
dermal
and
inhalation
MOEs
were
combined
using
the
formula
below:

MOE
TOTAL
=
1
__
(
1/
Dermal
MOE
)
+
(
1/
Inhalation
MOE)

2.1.3.2
Imazapyr
Non­
cancer
Risk
Summary
(
using
PHED,
ORETF,
and
Proprietary
Data)

All
of
the
non­
cancer
risk
unit
exposures
used
in
the
calculations
for
occupational
imazapyr
handlers
completed
in
this
assessment
are
included
in
Appendix
A.
A
summary
of
the
short­
and
intermediate­
term
risks
for
each
exposure
scenario
are
presented
in
Table
9.

Short­
and
Intermediate­
term
Combined
Risks
(
Dermal
and
Inhalation)

For
all
scenarios,
risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
at
either
baseline
PPE
or
with
the
addition
of
gloves.
Page
27
of
63
Table
9:
Summary
of
Short­
and
Intermediate­
Term
Imazapyr
Occupational
Handler
Non­
cancer
Risk
Estimates
Exposure
Scenario
Crop
or
Target
Application
Rate
a
Area
Treated
Daily
b
Combined
MOEs
c
Baseline
G
­
NR
PPE­
G,

DL­
NR
G
­
80%
R
G,
DL
­

80%
R
G
­
90%

R
G,
DL
­

90%
R
Eng
Cont
Mixer/
Loader
Mixing/
Loading
Liquids
for
Aerial
Applications
(
1a)
corn
0.014
lb
ae/
acre
1200
acres
360
43000
57000
45000
45000
60000
61000
120000
aquatic
sites
(
helicopter)
1.5
lb
ae/
acre
400
acres
10
1200
1600
1300
1300
1700
1700
3400
non­
crop
areas
(
including
highway
rights­
of­
way)
1.5
lb
ae/
acre
100
acres
40
4800
6400
5000
5000
6800
6800
14000
forestry
1.25
lb
ae/
acre
350
acres
14
1700
2200
1700
1700
2300
2300
4700
areas
grazed
or
cut
for
hay
1
lb
ae/
acre
100
acres
60
7200
9600
7500
7600
10000
10000
20000
Mixing/
Loading
Liquids
for
Groundboom
Applications
(
1b)
corn
0.014
lb
ae/
acre
200
acres
2200
260000
340000
270000
270000
360000
370000
720000
non­
crop
areas
(
including
highway
rights­
of­
way
and
commercial/
industrial
areas)
1.5
lb
ae/
acre
80
acres
50
6000
8000
6300
6300
8500
8500
17000
non­
crop
areas
(
including
turfgrass,
recreation
areas,
athletic
fields,
and
golf
course
roughs)
1.5
lb
ae/
acre
40
acres
100
12000
16000
13000
13000
17000
17000
34000
forestry
1.25
lb
ae/
acre
80
acres
60
7200
9600
7500
7600
10000
10000
20000
areas
grazed
or
cut
for
hay
1
lb
ae/
acre
80
acres
75
9000
12000
9400
9500
13000
13000
25000
Mixing/
Loading
Liquids
to
Support
Rights
of
Way
Equipment
(
1c)
non­
crop
areas
(
including
highway
rights­
of­
way)
1.5
lb
ae/
acre
80
acres
50
6000
8000
6300
6300
8500
8500
17000
forestry
1.25
lb
ae/
acre
80
acres
60
7200
9600
7500
7600
10000
10000
20000
Mixing/
Loading
Dry
Flowables
for
Aerial
Applications
(
2a)
corn
0.014
lb
ae/
acre
1200
acres
16000
16000
22000
16000
16000
22000
22000
110000
non­
cropland
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
non­
irrigation
ditches,

etc.)
1.5
lb
ae/
acre
100
acres
1700
1700
2400
1800
1800
2500
2500
12000
Mixing/
Loading
Dry
Flowables
for
Groundboom
Applications
(
2b)
corn
0.014
lb
ae/
acre
200
acres
94000
94000
130000
94000
95000
130000
130000
620000
non­
cropland
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
non­
irrigation
ditches,

etc.)
1.5
lb
ae/
acre
80
acres
2200
2200
3100
2200
2200
3100
3100
15000
Mixing/
Loading
Dry
Flowables
to
Support
Rights
of
Way
Equipment
(
2c)
non­
cropland
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
non­
irrigation
ditches,

etc.)
1.5
lb
ae/
acre
80
acres
2200
2200
3100
2200
2200
3100
3100
15000
Loading
Granulars
for
Aerial
Applications
(
3a)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
100
acres
12000
14000
23000
16000
17000
31000
33000
570000
Loading
Granulars
for
Tractor
Drawn
Spreader
Applications
(
3b)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
80
acres
14000
17000
29000
20000
21000
39000
41000
720000
Applicator
Applying
Liquid
Sprays
via
Aerial
Equipment
(
4)
corn
0.014
lb
ae/
acre
1200
acres
ND
ND
ND
ND
ND
ND
ND
210000
aquatic
sites
(
helicopter)
1.5
lb
ae/
acre
400
acres
ND
ND
ND
ND
ND
ND
ND
5700
non­
cropland
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
non­
irrigation
ditches,

etc.)
1.5
lb
ae/
acre
100
acres
ND
ND
ND
ND
ND
ND
ND
23000
forestry
1.25
lb
ae/
acre
350
acres
ND
ND
ND
ND
ND
ND
ND
7900
Table
9:
Summary
of
Short­
and
Intermediate­
Term
Imazapyr
Occupational
Handler
Non­
cancer
Risk
Estimates
Exposure
Scenario
Crop
or
Target
Application
Rate
a
Area
Treated
Daily
b
Combined
MOEs
c
Baseline
G
­
NR
PPE­
G,

DL­
NR
G
­
80%
R
G,
DL
­

80%
R
G
­
90%

R
G,
DL
­

90%
R
Eng
Cont
Page
28
of
63
areas
grazed
or
cut
for
hay
1
lb
ae/
acre
100
acres
ND
ND
ND
ND
ND
ND
ND
35000
Applying
Granulars
via
Aerial
Equipment
(
5)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
350
acres
ND
ND
ND
ND
ND
ND
ND
11000
Table
9:
Summary
of
Short­
and
Intermediate­
Term
Imazapyr
Occupational
Handler
Non­
cancer
Risk
Estimates
Exposure
Scenario
Crop
or
Target
Application
Rate
a
Area
Treated
Daily
b
Combined
MOEs
c
Baseline
G
­
NR
PPE­
G,

DL­
NR
G
­
80%
R
G,
DL
­

80%
R
G
­
90%

R
G,
DL
­

90%
R
Eng
Cont
Page
29
of
63
Applying
Liquid
Sprays
via
Groundboom
Equipment
(
6)
corn
0.014
lb
ae/
acre
80
acres
1100000
1100000
1300000
1100000
1100000
1400000
1400000
3100000
non­
crop
areas
(
including
highway
rights­
of­
way,

turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,
commercial/
industrial
areas)
1.5
lb
ae/
acre
80
acres
9900
9900
12000
10000
10000
13000
13000
29000
non­
crop
areas
(
including
turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,

commercial/
industrial
areas)
1.5
lb
ae/
acre
40
acres
20000
20000
25000
21000
21000
26000
26000
58000
forestry
1.25
lb
ae/
acre
80
acres
12000
12000
15000
12000
12000
16000
16000
35000
areas
grazed
or
cut
for
hay
1
lb
ae/
acre
80
acres
15000
15000
19000
15000
16000
20000
20000
44000
Applying
Liquid
Sprays
via
Rights
of
Way
Equipment
(
7)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
80
acres
110
370
500
370
370
500
500
NF
forestry
1.25
lb
ae/
acre
80
acres
130
440
600
450
450
600
600
NF
Applying
Granulars
via
Tractor
Drawn
Spreader
(
8)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
80
acres
13000
17000
27000
20000
20000
33000
34000
62000
Flagger
Flagging
for
Liquid
Sprays
via
Aerial
Equipment
(
9)
corn
0.014
lb
ae/
acre
350
acres
310000
ND
350000
ND
ND
350000
360000
13000000
Flagging
for
Granulars
via
Aerial
Equipment
(
10)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
100
acres
40000
ND
67000
ND
ND
72000
72000
420000
Mixer/
Loader/
Applicator
Mixing/
Loading/
Applying
Liquids
with
Low
Pressure
Handwand
(
11)
non­
crop
areas
(
including
turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,

commercial/
industrial
areas)
1.5
lb
ae/
acre
5
acres
23
5100
ND
5400
5400
ND
ND
NF
Mixing/
Loading/
Applying
Dry
Flowables
with
Low
Pressure
Handwand
(
using
liquid
data
as
surrogate)
(
12)
non­
crop
areas
(
including
turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,

commercial/
industrial
areas)
1.5
lb
ae/
acre
5
acres
23
5100
ND
5400
5400
ND
ND
NF
Loading/
Applying
Granulars
via
Push
Type
Spreader
(
ORETF)
(
13)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
5
acres
6500
10000
20000
11000
11000
21000
21000
NF
Loading/
Applying
Granulars
via
Pumpfeed
Backpack
Applicator
(
MRID#
451672­

01;
Temik)
(
14)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
10
acres
NBDD
11000
ND
12000
12000
ND
ND
NF
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
5
acres
NBDD
22000
ND
23000
23000
ND
ND
NF
Loading/
Applying
Granulars
via
Gravity­
feed
Backpack
Applicator
(
MRID
#
452507­

01;
Fipronil
study)
(
15)
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
10
acres
NBDD
1800
ND
1900
1900
ND
ND
NF
non­
crop
areas
(
railroad,
utility,
pipeline
and
highway
rights­
of­
way,
etc)
1.5
lb
ae/
acre
5
acres
NBDD
3600
ND
3800
3900
ND
ND
NF
Table
9:
Summary
of
Short­
and
Intermediate­
Term
Imazapyr
Occupational
Handler
Non­
cancer
Risk
Estimates
Exposure
Scenario
Crop
or
Target
Application
Rate
a
Area
Treated
Daily
b
Combined
MOEs
c
Baseline
G
­
NR
PPE­
G,

DL­
NR
G
­
80%
R
G,
DL
­

80%
R
G
­
90%

R
G,
DL
­

90%
R
Eng
Cont
Page
30
of
63
Mixing/
Loading/
Applying
Liquids
with
a
Handgun
Sprayer
(
ORETF
data)
(
16)
aquatic
sites
1.5
lb
ae/
acre
10
acres
NBDD
2600
4600
2600
2600
4700
4700
NF
non­
crop
areas
(
including
highway
rights­
of­
way,

turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,
commercial/
industrial
areas)
1.5
lb
ae/
acre
5
acres
NBDD
5200
9300
5200
5200
9300
9300
NF
forestry
1.25
lb
ae/
acre
5
acres
NBDD
6200
11000
6200
6200
11000
11000
NF
Mixing/
Loading/
Applying
Dry
Flowables
with
a
Handgun
Sprayer
(
LCO
ORETF
data)
(
17)
non­
crop
areas
(
including
turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,

commercial/
industrial
areas)
1.5
lb
ae/
acre
5
acres
NBDD
3900
6600
4000
4000
7000
7000
NF
Mixing/
Loading/
Applying
Water
Soluble
Bags
with
Handgun
Sprayer
(
ORETF
data)
(
18)
non­
crop
areas
(
including
highway
rights­
of­
way,

turfgrass
(
recreation
areas,
athletic
fields,
golf
course
roughs,
commercial/
industrial
areas)
1.5
lb
ae/
acre
5
acres
NBDD
3600
6200
3600
3600
6300
6300
NF
Mixing/
Loading/
Applying
Liquids
with
a
Backpack
Sprayer
(
19)
aquatic
sites
(
frill
or
girdle
treatments)
1.5
lb
ae/
acre
10
acres
NBDD
460
ND
470
470
ND
ND
140000
Mixing/
Loading/
Applying
Liquids
with
an
Injector
(
20)
forestry
0.1875
lb
ae/
gallon
NBDD
ND
ND
ND
ND
ND
ND
NF
Footnotes
*
MOEs
shown
in
bold
indicate
the
lowest
risk
mitigation
level
that
does
not
exceed
HED's
level
of
concern.

ND
No
Data
NBDD
No
Baseline
Dermal
Data
NF
Not
Feasible
a
Application
rates
are
the
maximum
application
rates
determined
from
EPA
registered
labels
for
imazapyr.

b
Amounts
handled
per
day
are
HED
estimates
of
acres,
square
feet,
or
cubic
feet
treated
or
gallons
applied
based
on
Exposure
SAC
SOP
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture,"
industry
sources,
and
HED
estimates.

c
Baseline:
Long­
sleeve
shirt,
long
pants,
no
gloves,
and
no
respirator.

PPE­
G­
NR:
Baseline
plus
chemical­
resistant
gloves,
and
no
respirator.

PPE­
G,
DL­
NR:
Coveralls
worn
over
long­
sleeve
shirt
and
long
pants,
chemical­
resistant
gloves,
and
no
respirator.

PPE­
G­
80%
R:
Baseline
plus
chemical­
resistant
gloves
and
an
80%
PF
(
quarter­
face
dust/
mist)
respirator.

PPE­
G,
DL­
80%
R:
Coveralls
worn
over
long­
sleeve
shirt
and
long
pants,
chemical­
resistant
gloves,
and
an
80%
PF
(
quarter­
face
dust/
mist)
respirator.

PPE­
G­
90%
R:
Baseline
plus
chemical­
resistant
gloves
and
a
90%
PF
(
half­
face
dust/
mist)
respirator.

PPE­
G,
DL­
90%
R:
Coveralls
worn
over
long­
sleeve
shirt
and
long
pants,
chemical­
resistant
gloves,
and
a
90%
PF
(
half­
face
dust/
mist)
respirator.

Eng
Controls:
Closed
mixing/
loading
system,
enclosed
cab,
or
enclosed
cockpit.
Page
31
of
63
2.1.4
Summary
of
Risk
Concerns
and
Data
Gaps
for
Occupational
Handlers
There
are
no
occupational
handler
scenarios
for
imazapyr
that
have
risks
associated
with
them
that
exceed
HED's
level
of
concern.
However,
there
are
a
few
occupational
handler
scenarios
for
imazapyr
that
have
data
gaps.

2.1.4.1
Summary
of
Risk
Concerns
For
most
scenarios,
risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
at
either
baseline
PPE
or
with
the
addition
of
chemical­
resistant
gloves.
With
respect
to
the
application
of
sprays
or
granules
with
aircraft,
the
only
data
available
are
for
enclosed
cockpits,
an
engineering
control.
Risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
with
the
use
of
enclosed
cockpit
engineering
controls.

2.1.4.2
Summary
of
Data
Gaps
A
few
data
gaps
were
identified
for
imazapyr
in
a
few
different
use
areas
that
include:

S
applying
sprayers
to
aquatic
sites
via
helicopters
(
PHED
data
for
fixed
wind
aerial
spray
applications
were
used
as
a
reasonable
surrogate);
and
S
mixing/
loading/
applying
liquids
to
trees
via
injection
equipment
(
no
surrogate
data
are
available
at
this
time).

2.1.5
Recommendations
For
Refining
Occupational
Handler
Risk
Assessment
In
order
to
refine
this
occupational
risk
assessment,
data
on
actual
use
patterns
including
rates,
timing,
and
areas
treated
would
better
characterize
imazapyr
risks.
Exposure
studies
for
many
equipment
types
that
lack
data
or
that
are
not
well
represented
in
PHED
(
e.
g.,
because
of
low
replicate
numbers
or
data
quality)
should
also
be
considered
based
on
the
data
gaps
identified
above
and
based
on
a
review
of
the
quality
of
the
data
used
in
this
assessment.

2.2
Occupational
Postapplication
Exposures
and
Risks
HED
uses
the
term
"
postapplication"
to
describe
exposures
to
individuals
that
occur
as
a
result
of
being
in
an
environment
that
has
been
previously
treated
with
a
pesticide
(
also
referred
to
as
reentry
exposure).
HED
believes
that
there
are
distinct
job
functions
or
tasks
related
to
the
kinds
of
activities
that
occur
in
previously
treated
areas.
Job
requirements
(
e.
g.,
the
kinds
of
jobs
to
cultivate
a
crop),
the
nature
of
the
crop
or
target
that
was
treated,
and
the
how
chemical
residues
degrade
in
the
environment
can
cause
exposure
levels
to
differ
over
time.
Each
factor
has
been
considered
in
this
assessment.
Page
32
of
63
2.2.1
Occupational
Postapplication
Exposure
Scenarios
Imazapyr
use
is
varied
as
it
can
be
used
on
corn,
on
rights
of
ways,
and
in
aquatic
settings.
As
a
result,
individuals
can
potentially
be
exposed
by
working
in
areas
that
have
been
previously
treated.
HED
is
concerned
about
these
kinds
of
exposures
one
could
receive
in
the
workplace.
When
assessing
postapplication
exposures
to
agricultural
crops,
HED
uses
a
concept
known
as
the
transfer
coefficient
to
numerically
represent
the
post­
application
exposures
one
would
receive
(
i.
e.,
generally
presented
as
cm2/
hour).
The
transfer
coefficient
concept
has
been
established
in
the
scientific
literature
and
through
various
exposure
monitoring
guidelines
published
by
the
U.
S.
EPA
and
international
organizations
such
as
Health
Canada
and
OECD
(
Organization
For
Economic
Cooperation
and
Development).
The
establishment
of
transfer
coefficients
also
forms
the
basis
of
the
work
of
the
Agricultural
Reentry
Task
Force.
The
transfer
coefficient
is
essentially
a
measure
of
the
contact
with
a
treated
surface
one
would
have
while
doing
a
task
or
activity.
These
values
are
defined
by
calculating
the
ratio
of
an
exposure
for
a
given
task
or
activity
to
the
amount
of
pesticide
on
leaves
(
or
other
surfaces)
that
can
rub
off
on
the
skin
resulting
in
an
exposure.
For
postapplication
exposures,
the
amounts
that
can
rub
off
on
the
skin
are
measured
using
techniques
that
specifically
determine
the
amount
of
residues
on
treated
leaves
or
other
surfaces
(
referred
to
as
transferable
residues
or
dislodgeable
foliar
residues)
rather
than
the
total
residues
contained
both
on
the
surface
and
absorbed
into
treated
leaves.
HED
has
developed
a
series
of
standard
transfer
coefficients
that
are
unique
for
variety
of
job
tasks
or
activities
that
are
used
in
lieu
of
chemical­
and
scenario­
specific
data.

As
with
the
handler
risk
assessment
process,
the
first
step
in
the
post­
application
risk
assessment
process
is
to
identify
the
kinds
of
individuals
that
are
likely
to
be
exposed
to
imazapyr
after
application.
In
order
to
do
this
in
a
consistent
manner,
HED
has
developed
a
series
of
general
descriptions
for
tasks
that
are
associated
with
post­
application
exposures.
HED
also
considers
whether
or
not
individuals
are
exposed
to
pesticides
as
part
of
their
employment
(
referred
to
as
occupational
risk
assessments).
Common
examples
include:
agricultural
harvesters,
scouting
activities
in
agriculture,
crop
maintenance
tasks
(
e.
g.,
irrigating,
hoeing
and
weeding),
and
turf
maintenance
(
golf
course
mowing).

The
next
step
in
the
risk
assessment
process
is
to
define
how
and
when
pesticides
are
applied
in
order
to
determine
the
level
of
transferable
residues
to
which
individuals
could
be
exposed
over
time.
Wherever
available,
use
and
usage
data
are
included
in
this
process
to
define
values
such
as
application
rates
and
application
frequency.
HED
always
completes
risk
assessments
using
maximum
application
rates
for
each
scenario
because
what
is
possible
under
the
label
(
the
legal
means
of
controlling
pesticide
use)
must
be
evaluated,
for
complete
stewardship,
in
order
to
ensure
HED
has
no
concern
for
the
specific
use.
In
order
to
define
the
amount
of
transferable
residues
to
which
individuals
can
be
exposed,
HED
relies
on
chemical­
and
crop­
specific
studies
as
described
in
HED
guidelines
for
exposure
data
collection
(
Series
875,
Occupational
and
Residential
Exposure
Test
Guidelines:
Group
B
­
Postapplication
Exposure
Monitoring
Test
Guidelines)
when
such
studies
are
available.
Page
33
of
63
There
are
no
imazapyr­
specific
dislodgeable
foliar
residue
studies.
In
this
situation,
HED
uses
a
standard
modeling
approach
that
can
predict
transferable
residues
over
time
(
best
described
in
HED's
SOPs
For
Residential
Exposure
Assessment).
Dermal
exposures
during
postapplication
activities
were
estimated
using
dermal
transfer
coefficients
from
the
Science
Advisory
Council
for
Exposure
Policy
Number
3.1:
Agricultural
Transfer
Coefficients,
August
2000
and
using
dislodgeable
foliar
residue
values
estimated
using
the
standard
default
assumption
that
20
percent
of
the
application
rate
is
initially
deposited
on
foliar
surfaces
and
the
residues
dissipate
at
a
rate
of
10
percent
per
day.

Next,
assessors
must
understand
how
exposures
to
imazapyr
occur
(
i.
e.,
frequency
and
duration)
and
how
the
patterns
of
these
occurrences
can
alter
the
effects
of
the
chemical
in
the
population
after
being
exposed
(
referred
to
as
dose
response).
This
is
supported
by
the
fact
that
several
areas
within
a
work
environment
may
be
treated
at
different
times.
For
example,
parts
of
agricultural
fields
in
a
localized
area
might
be
treated
over
several
weeks
because
of
an
infestation
with
a
concurrent
need
for
hand
labor
activities.
Therefore,
individuals
working
in
those
fields
might
be
exposed
from
contact
with
treated
foliage
over
an
extended
period
of
time
that
could
be
categorized
as
an
intermediate­
term
exposure
as
they
work
on
different
sections
of
fields.
Two
different
types
of
non­
cancer
risk
calculations
were
required
for
each
exposure
duration
considered.
The
durations
of
exposure
that
were
considered
for
non­
cancer
toxicity
were
shortterm
(#
30
days)
and
intermediate­
term
(
30
days
up
to
several
months).
However,
since
the
shortand
intermediate­
term
dermal
endpoints
are
the
same
(
i.
e.,
NOAEL
=
250
mg/
kg/
day
for
both
short­
term
and
intermediate­
term
exposures),
the
short­
and
intermediate­
term
postapplication
risks
are
numerically
equal.
Inhalation
exposures
are
thought
to
be
negligible
in
outdoor
postapplication
scenarios
because
of
the
low
vapor
pressure
and
due
to
the
infinite
dilution
expected
outdoors.
As
such,
inhalation
postapplication
exposures
are
not
considered
in
this
assessment.

The
use
of
personal
protective
equipment
or
other
types
of
equipment
to
reduce
exposures
for
post­
application
workers
is
not
considered
a
viable
alternative
for
the
regulatory
process.
This
is
described
in
some
detail
in
EPA's
Worker
Protection
Standard
(
40CFR170).
As
such,
an
administrative
approach
is
used
by
HED
to
reduce
the
risks
and
is
referred
to
as
the
Restricted
Entry
Interval
or
REI.
The
REI
is
time
period
follow
a
pesticide
application
during
which
entry
into
the
treated
area
is
restricted.
At
this
time,
the
REI
on
the
current
imazapyr
labels
is
12
hours.
Postapplication
risk
levels
are
generally
calculated
in
the
risk
assessment
process
on
a
chemical­,
crop­,
and
activity­
specific
basis.
To
establish
REIs,
HED
considers
postapplication
risks
on
varying
days
after
application.

HED
has
used
the
basic
approach
described
above
since
the
mid
1980s
for
calculating
postapplication
risks
to
pesticides.
From
that
time
to
the
present,
several
revisions
and
modifications
were
made
to
HED
policies
as
data
which
warranted
such
changes
became
available.
In
1995,
HED
issued
a
Data
Call­
In
for
postapplication
agricultural
data
that
prompted
the
formation
of
the
Agricultural
Reentry
Task
Force
(
ARTF).
This
task
force
has
generated
a
number
of
exposure
studies
and
associated
documents
that
are
currently
under
review
by
.
The
Page
34
of
63
work
of
the
ARTF
is
not
yet
complete,
however,
sufficient
data
were
available
from
the
group
that
warranted
a
significant
interim
change
in
HED
policy
related
to
the
data
which
were
already
available
as
the
efforts
of
the
ARTF
paralleled
push
for
tolerance
reassessment
stipulated
by
the
timelines
established
by
FQPA.
As
a
result
of
the
need
for
the
revision
and
using
the
latest
data,
HED
developed
a
revised
policy
on
August
7,
2000
entitled
Policy
003.1
Science
Advisory
Council
For
Exposure
Policy
Regarding
Agricultural
Transfer
Coefficients.
The
revision
to
this
policy
entailed
linking
worker
activities
to
more
specific
crop/
agronomic
groupings
and
making
better
use
of
the
available
occupational
post­
application
exposure
data.
In
the
new
policy,
transfer
coefficients
were
selected
to
represent
the
activities
associated
with
18
distinct
crop/
agronomic
groupings
based
on
different
types
of
vegetables,
trees,
berries,
vine/
trellis
crops,
turf,
field
crops,
and
bunch/
bundle
crops
(
e.
g.,
tobacco).
In
this
new
scheme
which
HED
uses
to
develop
scenarios
for
occupational
postapplication
exposures,
imazapyr
uses
were
identified
in
the
following
crop
groupings
from
the
policy:

C
Field/
row
crops,
tall
(
e.
g.,
corn).

Within
each
agronomic
group,
a
variety
of
cultural
practices
are
required
to
maintain
the
included
crops.
These
practices
are
varied
and
typically
involve
light
to
heavy
contact
with
immature
plants
as
well
as
with
more
mature
plants.
HED
selected
transfer
coefficient
values
in
its
revision
of
Policy
003
to
represent
this
range
of
exposures
within
each
agronomic
group.
In
the
policy,
transfer
coefficients
were
placed
in
1
of
5
generic
categories
based
on
the
exposures
relative
to
that
group.
These
5
categories
include:
very
low
exposure,
low
exposure,
medium
exposure,
high
exposure,
and
very
high
exposure.
Numerical
values
were
not
necessarily
assigned
to
each
category
for
each
crop
group.
Selections
depended
upon
the
actual
agronomic
practices
that
were
identified
by
for
each
group
(
i.
e.,
some
groups
had
2
assigned
transfer
coefficients
while
others
had
5).
The
transfer
coefficient
values
which
have
been
used
are
excerpted
directly
from
HED
policy
003.

2.2.2
Data/
Assumptions
for
Postapplication
Exposure
Scenarios
A
series
of
assumptions
and
exposure
factors
served
as
the
basis
for
completing
the
occupational
postapplication
worker
risk
assessments
for
agricultural
scenarios.
Each
assumption
and
factor
is
detailed
below
on
an
individual
basis.
In
addition
to
these
values,
transfer
coefficient
values
were
used
to
calculate
risk
estimates.
Several
chemical­
specific
residue
dissipation
studies
were
also
submitted
which
were
used
in
the
development
of
the
risk
values
.
The
transfer
coefficients
were
taken
from
HED's
revised
policy
entitled
Policy
003.1
Science
Advisory
Council
For
Exposure
Policy
Regarding
Agricultural
Transfer
Coefficients
(
August
7,
2000).
The
assumptions
and
factors
used
in
the
risk
calculations
are
presented
below:

C
There
are
many
factors
that
are
common
to
handler
and
postapplication
risk
assessments
such
as
body
weights,
duration,
and
ranges
of
application
rates.
Please
refer
to
the
assumptions
and
factors
in
Section
2.1.1.1
for
further
information
concerning
these
values
which
are
common
to
both
handler
and
postapplication
risk
assessments.
In
the
Page
35
of
63
postapplication
risk
assessment,
only
maximum
application
rates
were
considered
for
each
of
the
agronomic
groups
contained
in
Policy
003.

C
Levels
of
Concern:
HED
has
established
the
following
levels
of
concern
(
LOC)
for
occupational
postapplication
risks:

S
margin
of
exposure
of
less
than
100
for
occupational
non­
cancer
risks.

2.2.3
Occupational
Postapplication
Exposure
and
Non­
cancer
Risks
The
occupational
postapplication
exposure
and
non­
cancer
risk
calculations
are
presented
in
this
section.
Postapplication
risks
diminish
over
time
because
imazapyr
residues
eventually
dissipate
in
the
environment.
As
a
result,
risk
values
were
calculated
over
time
based
on
changing
residue
levels.

Postapplication
exposures
to
agricultural
workers
are
summarized
in
Table
10
below.
The
following
assumptions
are
used
in
the
postapplication
exposure
assessment:

°
Application
Rate:
maximum
label
rate
for
each
crop
°
Exposure
Duration:
8
hours
°
Body
Weight:
70
kg
for
short­
term
exposures
°
Dermal
absorption:
100%
°
Fraction
of
active
ingredient
retained
on
foliage:
20
percent
°
Fraction
of
active
ingredient
dissipating
per
day:
10
percent
°
Transfer
coefficients
from
Policy
3.1
Equations/
Calculations
The
following
equations
were
used
to
calculate
risks
for
workers
performing
postapplication
activities:

DFRt
(
µ
g/
cm2)
=
Application
Rate
(
lb
ae/
acre)
x
F
x
(
1­
D)
t
x
4.54E8
µ
g/
lb
x
2.47E­
8
acre/
cm2
Where:

DFRt
=
dislodgeable
foliage
residue
on
day
"
t"
(
µ
g/
cm2)
Rate
=
application
rate
(
lb
ai/
acre)
F
=
fraction
of
ai
retained
on
foliage
(
unitless)
D
=
fraction
of
residue
that
dissipates
daily
(
unitless)

Daily
Dermal
Doset
=
DFRt
(
µ
g/
cm2)
x
1E­
3
mg/
µ
g
x
Tc
(
cm2/
hr)
x
DA
x
ET
(
hrs/
day)
BW
(
kg)
Where:
t
=
number
of
days
after
application
day
(
days)
DFRt
=
dislodgeable
foliage
residue
on
day
"
t"
(
µ
g/
cm2)
Tc
=
transfer
coefficient
(
cm2/
hr)
DA
=
dermal
absorption
factor
(
unitless)
ET
=
exposure
time
(
hr/
day)
Page
36
of
63
BW
=
body
weight
(
kg)

Non­
cancer
Risk
Summary:
For
all
agricultural
postapplication
exposure
scenarios,
postapplication
occupational
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
on
day
0
 
approximately
12
hours
following
application.
A
summary
of
the
results
for
each
crop/
activity
combination
considered
for
each
time­
frame
is
also
provided
in
Table
10.

Table
10:
Summary
of
Imazapyr
Postapplication
Activities
and
Risks
Crops
Transfer
Coefficients
(
cm2/
hr)
a
Activities
Short­
and
Intermediate­
Term
MOE
at
Day
0
(
12
hours
after
application)
b,
c,
d
Corn
(
0.014
lb
ae/
A)
100
Scouting,
Hand
Weeding
700000
400
Scouting
170000
1000
Irrigation,
Scouting,
Hand
Weeding
70000
17000
Detasseling,
Hand
Harvesting
4100
Footnotes:
a
Crop­
specific
activities
and
transfer
coefficients
from
Science
Advisory
Council
for
Exposure
Policy
Number
3.1,
Agricultural
Transfer
Coefficients
adopted
May
7,
1998,
and
revised
August
7,
2000.
b
The
DFR
is
based
on
default
assumption
that
20%
of
the
application
rate
is
available
for
transfer
on
day
0.
c
Daily
Dermal
Dose
=
DFR
(
µ
g/
cm2)
x
conversion
factor
(
1E­
3
mg/
µ
g)
x
Tc
(
cm2/
hr)
x
DA
x
ET
(
8
hrs/
day)
/
BW
(
70
kg).
d
Short­
and
Intermediate­
Term
Dermal
MOE
=
Short­
and
Intermediate­
term
NOAEL
(
250
mg
ai/
kg/
day)
÷
Daily
Dermal
Dose
(
mg
ai/
kg/
day).

The
restricted
entry
interval
(
REI)
on
the
parent
label
is
12
hours,
however,
imazapyr
is
Toxicity
Category
I
for
primary
eye
irritation.
Under
the
Worker
Protection
Standard
(
WPS;
40
CFR
Part
170),
an
interim
48­
hour
REI
is
required
for
an
active
ingredient
that
has
an
acute
toxicity
of
Category
I
for
primary
eye
irritation.

2.2.4
Off
Target
Non­
Occupational
Exposure
Spray
drift
is
always
a
potential
(
postapplication)
source
of
exposure
to
residents
nearby
to
spraying
operations.
This
is
particularly
the
case
with
aerial
application,
but,
to
a
lesser
extent,
could
also
be
a
potential
source
of
exposure
from
the
ground
application
method
employed
for
imazapyr.
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
Page
37
of
63
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.

2.2.5
Summary
of
Occupational
Postapplication
Risk
Concerns
and
Data
Gaps
For
all
agricultural
postapplication
exposure
scenarios,
postapplication
occupational
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
on
day
0
 
approximately
12
hours
following
application.

HED
has
used
the
latest
information
to
complete
this
postapplication
risk
assessment
for
imazapyr.
Data
gaps
exist
such
as
a
lack
of
imazapyr
specific
postapplication
studies.

2.2.6
Recommendations
For
Refining
Occupational
Postapplication
Risk
assessment
To
refine
this
occupational
risk
assessment,
data
on
actual
use
patterns
including
rates,
timing,
and
the
kinds
of
tasks
that
are
required
to
produce
agricultural
commodities
and
other
products
would
better
characterize
imazapyr
risks.
Exposure
studies
for
many
cultural
practices
that
lack
data
or
that
are
not
well
represented
in
the
revised
transfer
coefficient
policy
should
also
be
considered
based
on
the
data
gaps
identified
above.

3.0
Residential
and
Other
Non­
Occupational
Exposures
and
Risks
It
has
been
determined
there
is
a
potential
for
exposure
in
residential
settings
during
the
application
process
for
homeowners
who
use
products
containing
imazapyr.
There
is
also
a
potential
for
exposure
from
entering
imazapyr­
treated
areas,
such
as
patios
and
lakes
that
could
lead
to
exposures
to
adults
and
children.
Risk
assessments
have
been
completed
for
both
residential
handler
and
postapplication
scenarios.

3.1
Residential
Handler
Exposures
and
Risks
HED
uses
the
term
"
handlers"
to
describe
those
individuals
who
are
involved
in
the
pesticide
application
process.
HED
believes
that
there
are
distinct
tasks
related
to
applications
and
that
exposures
can
vary
depending
on
the
specifics
of
each
task
as
was
described
above
for
occupational
handlers.
Residential
handlers
are
addressed
somewhat
differently
by
HED
as
homeowners
are
assumed
to
complete
all
elements
of
an
application
without
use
of
any
protective
equipment.

3.1.1
Handler
Exposure
Scenarios
Page
38
of
63
Scenarios
are
used
to
define
risks
based
on
the
U.
S.
EPA
Guidelines
For
Exposure
Assessment
(
U.
S.
EPA;
Federal
Register
Volume
57,
Number
104;
May
29,
1992).
Assessing
exposures
and
risks
resulting
from
residential
uses
is
very
similar
to
assessing
occupational
exposures
and
risks,
with
the
following
exceptions:

C
Residential
handler
exposure
scenarios
are
considered
to
be
short­
term
only
due
to
the
infrequent
uses
associated
with
homeowner
products;

C
A
tiered
approach
for
personal
protection
using
increasing
levels
of
PPE
is
not
used
in
residential
handler
risk
assessments.
Homeowner
handler
assessments
are
based
on
the
assumption
that
individuals
are
wearing
shorts,
short­
sleeved
shirts,
socks,
and
shoes;

C
Homeowner
handlers
are
expected
to
complete
all
tasks
associated
with
the
use
of
a
pesticide
product
including
mixing/
loading
if
needed
as
well
as
the
application;

C
Label
use­
rates
and
use­
information
specific
to
residential
products
serve
as
the
basis
for
the
risk
calculations;
and
C
Area/
volumes
of
spray
or
chemical
used
in
the
risk
assessment
are
based
on
HED's
guidance
specific
to
residential
use­
patterns.

It
has
been
determined
that
exposure
to
pesticide
handlers
is
likely
during
the
residential
use
of
imazapyr
on
driveways,
parking
areas,
brick
walls,
gravel
pathways,
patios,
along
sidewalks
and
bare
ground.
The
anticipated
use
patterns
and
current
labeling
indicate
two
major
residential
exposure
scenarios
based
on
the
types
of
equipment
and
techniques
that
can
potentially
be
used
to
make
imazapyr
applications.
The
quantitative
exposure/
risk
assessment
developed
for
residential
handlers
is
based
on
these
scenarios.

Mixer/
Loader/
Applicators:
(
1)
Liquid:
Low
Pressure
Handwand;
and
(
2)
Liquid:
Watering
Can.

3.1.2
Data
and
Assumptions
For
Handler
Exposure
Scenarios
A
series
of
assumptions
and
exposure
factors
served
as
the
basis
for
completing
the
residential
handler
risk
assessments.
Each
assumption
and
factor
is
detailed
below.
In
addition
to
these
factors,
unit
exposures
were
used
to
calculate
risk
estimates.
These
unit
exposures
were
taken
from
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
studies.

Assumptions
and
Factors:
The
assumptions
and
factors
used
in
the
risk
calculations
include:

C
Exposure
factors
used
to
calculate
daily
exposures
to
handlers
were
based
on
applicable
data
if
available.
When
appropriate
data
are
unavailable,
values
from
a
scenario
deemed
Page
39
of
63
similar
might
be
used.
As
an
example,
mixer/
loader/
applicator
data
for
hose­
end
sprayers
were
used
to
assess
sprinkler
can
applications.
These
application
methods
are
believed
to
be
similar
enough
to
bridge
the
data.
See
Appendix
B/
Table
B1
for
more
details.

C
HED
always
considers
the
maximum
application
rates
allowed
by
labels
in
its
risk
assessments.

C
Residential
risk
assessments
are
based
on
estimates
of
what
homeowners
would
typically
treat.
The
factors
used
for
the
imazapyr
assessment
were
from
the
Health
Effects
Division
Science
Advisory
Committee
Policy
12:
Recommended
Revisions
To
The
Standard
Operating
Procedures
For
Residential
Exposure
Assessment
which
was
completed
on
February
22,
2001
and
on
best
professional
judgement.
The
daily
volumes
handled
and
area
treated,
used
in
each
residential
scenario,
include:

C
1000
square
feet
for
spot
applications
to
driveways,
parking
areas,
brick
walls,
gravel
pathways,
patios,
along
sidewalks
and
bare
ground
using
watering
cans
and
low
pressure
handwand
sprayers.

Residential
Handler
Exposure
Studies:
The
unit
exposures
that
were
used
in
this
assessment
were
based
on
the
Outdoor
Residential
Exposure
Task
Force
studies.

ORETF
Handler
Studies
(
MRID
449722­
01):
A
report
was
submitted
by
the
ORETF
(
Outdoor
Residential
Exposure
Task
Force)
that
presented
data
in
which
the
application
of
various
products
used
on
turf
by
homeowners
and
lawncare
operators
(
LCOs)
was
monitored.
All
of
the
data
submitted
in
this
report
were
completed
in
a
series
of
studies.
The
study
that
monitored
homeowner
exposures
while
using
a
hose­
end
sprayer
(
ORETF
Study
OMA004).

Homeowner
Hose
End
Sprayer:
A
mixer/
loader/
applicator
study
was
performed
by
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
using
Diazinon
as
a
surrogate
compound
to
determine
"
generic"
exposures
to
individuals
applying
a
pesticide
to
turf
with
a
dial
type
hose
end
sprayer.
Dermal
and
inhalation
exposures
were
estimated
using
whole­
body
passive
dosimeters
and
breathing­
zone
air
samples
on
OVS
tubes.
Inhalation
exposure
was
calculated
using
an
assumed
respiratory
rate
of
17
liters
per
minute
for
light
work
(
NAFTA,
1999),
the
actual
sampling
time
for
each
individual,
and
the
pump
flow
rate.
All
results
were
normalized
for
pounds
active
ingredient
handled.
A
total
of
30
replicates
were
monitored
throughout
the
study.

Diazinon
(
25%
emulsifiable
concentrate)
was
applied
by
homeowners
to
actual
residential
lawns
at
a
site
in
Maryland.
A
target
application
rate
of
4
pounds
active
ingredient
was
used
for
all
replicates.
Each
replicate
monitored
the
test
subject
treating
5,000
ft2
of
turf
and
handling
a
total
of
0.5
lb
ai/
replicate.
The
exposure
periods
(
mixing/
loading/
applying)
averaged
seventy­
five
minutes.
Dermal
exposure
was
measured
using
inner
and
outer
whole
body
dosimeters,
hand
washes,
face/
neck
washes,
and
personal
air
monitoring
devices.
In
general,
concurrent
lab
spikes
produced
mean
recoveries
in
the
range
of
87­
103
percent.
Adjustment
for
recoveries
from
field
Page
40
of
63
fortifications
(
79­
104
%)
were
performed
on
each
dosimeter
section
or
sample
matrix
for
each
study
participant,
using
the
mean
recovery
for
the
closest
field
spike
level
for
each
matrix
and
correcting
the
value
to
100
percent.
The
unit
exposures
are
presented
below
in
Table
11.
[
Note
the
data
were
found
to
be
lognormally
distributed.
As
a
result,
all
exposures
are
geometric
means.]

Table
11:
Unit
Exposures
Obtained
From
ORETF
Hose
End
Sprayer
Studies
(
MRID
449722­
01)

Type
Dermal:
Short
Pants,
Short
Sleeves
(
mg
ai/
lb
handled)
Inhalation
(
µ
g
ai/
lb
handled)

Hose­
end
(
Mix­
your­
own)
11
17
All
unit
exposures
are
geometric
means.

ORETF
Handler
Studies
(
MRID
444598­
01):
A
report
was
submitted
by
the
ORETF
(
Outdoor
Residential
Exposure
Task
Force)
that
presented
data
in
which
the
application
of
various
products
used
on
fruit
trees
and
ornamentals
by
homeowners
was
monitored.
All
of
the
data
submitted
in
this
report
were
completed
in
a
series
of
studies.
The
study
that
monitored
homeowner
exposure
scenarios
using
a
low
pressure
handwand
(
ORETF
Study
OMA006)
is
summarized
below.

Homeowner
Hand­
held
Sprayer:
The
data
collected
reflect
the
dermal
and
respiratory
exposure
of
homeowners
mixing,
loading
and
applying
RP­
2
Liquid
(
21%),
a
carbaryl
end­
use
product.
Applications
were
made
by
volunteers
to
two
18
foot
rows
of
tomatoes
and
one
18
foot
row
of
cucumber.
The
only
test
field
was
located
in
Florida.
For
this
study,
RP­
2
Liquid
(
21%)
exposures
were
monitored
using
low­
pressure
handwand
sprayers.
Exposure
for
each
spray
method/
product
combination
was
monitored
using
40
handlers
(
replicates).
Of
the
40
replicates
per
spray
method/
product
combination,
20
wore
household
latex
gloves
and
20
performed
tasks
without
gloves.

Each
replicate
opened
the
end­
use
product,
added
it
to
the
application
implement,
adjusted
the
setting
and
applied
it
to
the
vegetable
rows.
After
application
to
the
vegetable
rows,
dosimeters
were
collected.
Inhalation
exposure
was
monitored
with
personal
air
sampling
pumps
with
OVS
tubes
attached
to
the
shirt
collar
in
the
breathing
zone.
Dermal
exposure
was
assessed
by
extraction
of
carbaryl
from
inner
and
outer
100
percent
cotton
dosimeters,
face/
neck
wipes,
and
glove
and
hand
washes.
The
inner
and
outer
dosimeters
were
segmented
into:
lower
and
upper
arms,
lower
and
upper
legs,
front
and
back
torso.

Field
fortification
recoveries
for
passive
dosimeters
averaged
84.3
percent
for
inner
and
77.7
percent
for
outer
dosimeters.
Face
and
neck
wipe
fortifications
average
84.8
percent.
Handwash
and
Inhalation
OVS
tube
field
fortification
averaged
>
90
percent.
Inner
and
outer
Page
41
of
63
dosimeter
and
face
and
neck
wipe
residues
were
adjusted
for
field
fortification
results.
Handwash
and
inhalation
residues
were
not
adjusted.

Laboratory
method
validation
for
each
matrix
fell
within
the
acceptable
range
of
70
to
120
percent.
The
limit
of
quantitation
(
LOQ)
was
1.0
µ
g/
sample
for
all
media
except
the
inhalation
monitors
where
the
LOQ
was
0.01
µ
g/
sample.
The
limit
of
detection
(
LOD)
was
0.5
µ
g/
sample
for
all
media
except
the
inhalation
monitors
where
the
LOQ
was
0.005
µ
g/
sample.

Dermal
exposure
was
determined
by
adding
the
values
from
the
bare
hand
rinses,
face/
neck
wipes
to
the
outer
dosimeter
lower
legs
and
lower
arms
plus
the
inner
dosimeter
front
and
rear
torso,
upper
legs,
lower
legs,
lower
arms,
and
upper
arms.
This
accounts
for
the
residential
handler
wearing
short­
sleeved
shirt
and
short
pants.
Unit
exposures
for
each
application
method
are
presented
below
in
Table
12.

Table
12:
Unit
Exposures
Obtained
From
ORETF
Homeowner
Low
Pressure
Handwand
Studies
(
MRID
444598­
01)

Type
Dermal:
Short
Pants,
Short
Sleeves
(
mg
ai/
lb
handled)
Inhalation
(
µ
g
ai/
lb
handled)

Low
Pressure
Handwand
38
2.7
All
unit
exposures
are
geometric
means.

3.1.3
Residential
Handler
Exposure
and
Non­
Cancer
Risk
Estimates
The
residential
handler
exposure
and
non­
cancer
risk
estimations
are
presented
in
this
section.
Noncancer
risks
were
estimated
using
the
Margin
of
Exposure
(
MOE)
as
described
above.
Assessing
exposures
and
risks
resulting
from
residential
uses
is
very
similar
to
assessing
occupational
exposures
and
risks,
except
as
described
above
in
Section
3.1.1.
The
other
major
difference
with
residential
risk
assessments
is
that
the
uncertainty
factor
which
defines
the
level
of
risk
concern
has
the
additional
FQPA
safety
factor
applied.
The
overall
uncertainty
factor
applied
to
imazapyr
for
residential
handler
risk
assessments
is
100
which
is
based
on
the
FQPA
safety
factor
of
1x
along
with
the
10x
for
inter­
species
extrapolation
and
10x
for
intra­
species
sensitivity.

Noncancer
Risk
Summary:
All
of
the
unit
exposure
values
used
in
the
noncancer
risk
estimations
for
residential
imazapyr
handlers
in
this
assessment
are
included
in
Appendix
B/
Table
B2.
A
brief
summary
of
the
results
for
each
exposure
scenario
is
also
provided
below.

The
data
used
by
HED
have
provided
a
basic
broad
overview
of
the
uses
of
imazapyr
around
a
residential
environment
(
i.
e.,
the
database
is
fairly
complete).
HED
believes
that
the
scenarios
assessed
in
this
document
represent
worse­
case
exposures
and
risks
resulting
from
use
of
imazapyr
in
residential
environments.
Data
quality
should
be
considered
in
the
interpretation
of
the
uncertainties
associated
with
each
risk
presented.
Page
42
of
63
Short­
term
risks
for
residential
handlers
(
intermediate­
term
exposures
are
not
likely,
because
of
the
sporadic
nature
of
applications
by
homeowners)
are
presented
in
Table
13.
For
all
scenarios,
risks
are
below
HED's
level
of
concern
(
i.
e.,
MOEs
are
greater
than
100)
assuming
handlers
are
wearing
short­
sleeve
shirt,
short
pants,
shoes,
and
socks.

Table
13:
Summary
of
Short­
Term
Imazapyr
Residential
Handler
Noncancer
Risk
Estimates
Exposure
Scenario
Crop
or
Target
Application
Rate
a
Area
Treated
Daily
b
Baseline
MOEs
Dermal
Inhalation
Combined
Mixer/
Loader/
Applicator
Mixing/
Loading/
Applying
Liquids
with
Low
Pressure
Handwand
(
1)
residential
sites
­­
no
vegetation
(
driveways,
parking
areas,
walks,
paths,
patios)
0.006
lb
ae/
gal
1000
sq
ft
25000
350000000
25000
Mixing/
Loading/
Applying
Liquids
with
Hose­
End
Sprayer
(
ORETF
data)
(
2)
residential
sites
­­
no
vegetation
(
driveways,
parking
areas,
walks,
paths,
patios)
0.006
lb
ae/
gal
1000
sq
ft
85000
55000000
85000
Footnotes
a
Application
rates
are
the
maximum
application
rates
provided
by
for
imazapyr
in
all
cases.
b
Amount
handled
per
day
values
are
HED
estimates
of
area
treated
or
gallons
applied
based
on
Exposure
SAC
SOP
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture,"
industry
input,
and
HED
estimates.

3.1.4
Summary
of
Risk
Concerns
and
Data
Gaps
for
Handlers
Noncancer
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100)
for
all
residential
handler
scenarios.
No
key
data
gaps
have
been
identified
by
HED
at
this
time
for
residential
handlers.

3.1.5
Recommendations
For
Refining
Residential
Handler
Risk
Assessment
In
order
to
refine
this
residential
risk
assessment,
more
data
on
actual
use
patterns
including
rates,
timing,
and
areas
treated
would
better
characterize
imazapyr
risks.

3.2
Residential
Postapplication
Exposures
and
Risks
HED
uses
the
term
"
postapplication"
to
describe
exposures
to
individuals
that
occur
as
a
result
of
being
in
an
environment
that
has
been
previously
treated
with
a
pesticide.
Imazapyr
can
be
used
in
many
areas
that
can
be
frequented
by
the
general
population
including
residential
use
areas
(
e.
g.,
patios
and
driveways)
as
well
occupational
use
areas
(
e.
g.,
lakes,
golf
courses,
and
fairground
sites).
HED
generically
refers
to
these
exposures
as
"
residential"
in
nature.

3.2.1
Residential
Postapplication
Exposure
Scenarios
A
wide
array
of
individuals
of
varying
ages
can
potentially
be
exposed
to
imazapyr
when
they
do
activities
in
areas
that
have
been
previously
treated.
Postapplication
exposure
scenarios
were
developed
for
each
residential
setting
where
imazapyr
can
be
used.
Assessing
postapplication
Page
43
of
63
exposures
and
risks
resulting
from
residential
uses
is
very
similar
to
assessing
occupational
postapplication
exposures
and
risks,
except
in
residential
assessments:

S
exposures
were
calculated
for
children
of
differing
ages
as
well
as
adults;
and
S
non­
dietary
ingestion
exposures
to
toddlers
were
calculated
(
i.
e.,
soil
ingestion,
hand­/
object­
to­
mouth).

HED
relies
on
a
standardized
approach
for
completing
residential
risk
assessments
that
is
based
on
current
imazapyr
labels
and
guidance
contained
in
the
following
five
documents.

S
Series
875,
Residential
and
Residential
Exposure
Test
Guidelines:
Group
B
­
Postapplication
Exposure
Monitoring
Test
Guidelines
(
V
5.4,
Feb.
1998)
This
document
provides
general
risk
assessment
guidance
and
criteria
for
analysis
of
residue
dissipation
data.

S
Standard
Operating
Procedures
For
Residential
Exposure
Assessment
(
Dec.
1997)
This
document
provides
the
overarching
guidance
for
developing
residential
risk
assessments
including
scenario
development,
algorithms,
and
values
for
inputs.

S
Science
Advisory
Council
For
Exposure
Policy
003.1
(
Aug.
2000):
Agricultural
Transfer
Coefficients
This
document
provides
transfer
coefficients
which
have
been
used
to
assess
exposures
in
home
gardens.

S
Science
Advisory
Council
For
Exposure
Policy
12
(
Feb.
2001):
Recommended
Revisions
To
The
Standard
Operating
Procedures
(
SOPs)
For
Residential
Exposure
Assessment
This
document
provides
additional,
revised
guidance
for
completing
residential
exposure
assessments.

S
Overview
of
Issues
Related
To
The
Standard
Operating
Procedures
For
Residential
Exposure
Assessment
(
August
1999
Presentation
To
The
FIFRA
SAP)
This
document
provides
rationale
for
HED
changes
in
SOPs.

When
the
guidance
in
current
labels
and
these
documents
is
considered,
it
is
clear
that
HED
should
consider
children
of
differing
ages
as
well
as
adults
in
its
assessments.
It
is
also
clear
that
different
age
groups
should
be
considered
in
different
situations.
The
populations
that
were
considered
in
the
assessment
include:

C
Residential
Adults:
these
individuals
are
members
of
the
general
population
that
are
exposed
to
chemicals
by
engaging
in
activities
at
their
residences
(
e.
g.,
patios
or
driveways)
and
also
in
areas
not
limited
to
their
residence
(
e.
g.,
fairgrounds
and
lakes)
previously
treated
with
a
pesticide.
These
kinds
of
exposures
are
attributable
to
a
variety
of
activities
and
usually
addressed
by
HED
in
risk
assessments
by
considering
a
representative
activity
as
the
basis
for
the
exposure
calculation.
Page
44
of
63
C
Residential
Children:
children
are
members
of
the
general
population
that
can
also
be
exposed
in
their
residences
(
e.
g.,
patios
and
driveways
as
well
as
other
areas
previously
treated
with
a
pesticide
(
e.
g.,
fairgrounds
and
lakes).
These
kinds
of
exposures
are
attributable
to
a
variety
of
activities
such
as
playing
outside,
home
gardening,
or
playing
with
a
companion
animal.
Toddlers
have
been
selected
as
a
sentinel
(
or
representative)
population
for
imazapyr
postapplication
residential.

The
SOPs
For
Residential
Exposure
Assessment
define
several
scenarios
that
apply
to
uses
specified
in
current
labels.
These
scenarios
served
as
the
basis
for
the
residential
postapplication
assessment
along
with
the
modifications
to
them
and
the
additional
data
and
approaches
described
above.
HED
used
this
guidance
to
define
the
exposure
scenarios
that
essentially
include
dermal
and
nondietary
ingestion
exposure
to
toddlers
on
treated
lawns
and
dermal
exposure
to
adults
on
treated
lawns.
The
SOPs
and
the
associated
scenarios
are
presented
below:

C
Dose
from
dermal
exposure
on
treated
turf:
Postapplication
dermal
dose
calculations
for
toddlers
from
playing
on
treated
turf;

C
Dose
from
ingestion
of
imazapyr
granules
from
treated
turf:
Postapplication
dose
calculations
for
toddlers
from
episodic
nondietary
ingestion
of
pesticide
granules
picked
up
from
treated
turf
(
i.
e.,
those
residues
that
are
swallowed
when
toddlers
pick
up
granules
from
treated
turf
and
put
the
granules
in
their
mouth);

C
Dose
from
hand­
to­
mouth
activity
from
treated
turf:
Postapplication
dose
calculations
for
toddlers
from
incidental
nondietary
ingestion
of
pesticide
residues
on
treated
turf
from
hand­
to­
mouth
transfer
(
i.
e.,
those
residues
that
are
swallowed
when
toddlers
get
pesticide
residues
on
their
hands
from
touching
treated
turf
and
then
put
their
hands
in
their
mouth);

C
Dose
from
object­
to­
mouth
activity
from
treated
turf:
Postapplication
dose
calculations
for
toddlers
from
incidental
nondietary
ingestion
of
pesticide
residues
on
treated
turf
from
object­
to­
mouth
transfer
(
i.
e.,
those
residues
that
swallowed
when
toddlers
put
treated
turf
in
their
mouths);

C
Dose
from
soil
ingestion
activity
from
treated
turf:
Postapplication
dose
calculations
for
toddlers
from
incidental
nondietary
ingestion
of
pesticide
residues
from
ingesting
soil
in
a
treated
turf
area
(
i.
e.,
those
soil
residues
are
swallowed
when
toddlers
get
pesticide
residues
on
their
hands
from
touching
treated
soil
and
then
put
their
hands
in
their
mouth);

C
Dose
from
dermal
exposure
to
treated
lakes
(
from
swimming):
Postapplication
dermal
dose
calculations
for
adults
and
toddlers
from
swimming
in
treated
lakes
and
ponds;
and
Page
45
of
63
C
Dose
from
incidental
ingestion
of
water
from
treated
lakes
(
from
swimming):
Postapplication
incidental
ingestion
dose
calculations
for
toddlers
from
swimming
in
treated
lakes
and
ponds.

3.2.2
Data
and
Assumptions
for
Residential
Postapplication
Exposure
Scenarios
A
series
of
assumptions
and
exposure
factors
served
as
the
basis
for
completing
the
residential
postapplication
risk
assessments.
The
assumptions
and
factors
used
in
the
risk
calculations
are
consistent
with
current
HED
policy
for
completing
residential
exposure
assessments
(
i.
e.,
SOPs
For
Residential
Exposure
Assessment).
The
values
used
in
this
assessment
include:

C
There
are
many
factors
that
are
common
to
the
occupational
and
residential
postapplication
risk
assessments.
Please
refer
to
the
assumptions
and
factors
in
Section
2.1.1
for
further
information
concerning
these
common
values.

C
HED
combines
risks
resulting
from
exposures
to
individual
chemicals
when
it
is
likely
they
can
occur
simultaneously
based
on
the
use
pattern
and
the
behavior
associated
with
the
exposed
population.
Within
a
residential
assessment,
this
can
take
two
forms.
The
first
approach
is
to
add
together
risks
for
individual
exposure
scenarios
from
all
likely
sources
of
exposure
such
as
after
an
application
to
turf.
For
imazapyr,
HED
has
combined
risks
(
i.
e.,
MOEs)
for
different
kinds
of
exposures
for
the
turf
scenarios
(
i.
e.,
dermal,
hand­
tomouth
object­
to­
mouth,
and
soil
ingestion).
These
represent
the
standard
set
of
exposures
that
are
typically
combined
when
chemicals
are
used
on
turf,
because
it
is
logical
they
can
co­
occur.

C
Exposures
to
adults
and
children
on
treated
turf
have
been
addressed
using
the
latest
HED
standard
operating
procedures
for
this
scenario
including:

S
5
percent
of
the
application
rate
has
been
used
to
calculate
the
day­
zero
residue
levels
used
for
assessing
risks
from
hand­
to­
mouth
behaviors;

S
20
percent
of
the
application
rate
has
been
used
to
calculate
the
day­
zero
residue
levels
used
for
assessing
risks
from
object­
to­
mouth
behaviors
(
a
higher
percent
transfer
has
been
used
for
object­
to­
mouth
behaviors,
because
it
involves
a
teething
action
believed
to
be
more
analogous
to
DFR/
leaf
wash
sample
collection
where
20
percent
is
also
used);

S
the
transfer
coefficients
used
are
those
presented
at
the
1999
Agency
presentation
before
the
FIFRA
Science
Advisory
Panel
that
have
been
adopted
in
routine
practice
by
HED;

S
3
year
old
toddlers
are
expected
to
weigh
15
kg
(
average
of
1
to
6
year
olds);

S
hand­
to­
mouth
exposures
are
based
on
a
frequency
of
20
events/
hour
and
a
surface
area
per
event
of
20
cm2
representing
the
palmar
surfaces
of
three
fingers;

S
saliva
extraction
efficiency
is
50
percent
meaning
that
every
time
the
hand
goes
in
the
mouth
approximately
½
of
the
residues
on
the
hand
are
removed;
Page
46
of
63
S
object­
to­
mouth
exposures
are
based
on
a
25
cm2
surface
area;

S
exposure
durations
are
expected
to
be
2
hours
based
on
information
in
HED's
Exposure
Factors
Handbook;

S
soil
residues
are
contained
in
the
top
centimeter
and
soil
density
is
0.67
mL/
gram;
and
S
dermal,
hand­
and
object­
to­
mouth,
and
soil
ingestion
are
combined
to
represent
an
overall
risk
from
exposure
to
turf
while
granular
ingestion
is
considered
to
be
a
much
more
episodic
behavior
and
is
considered
separately
by
HED.

°
Exposures
to
adults
and
children
swimming
in
treated
lakes
and
ponds
have
been
addressed
using
SWIMODEL
V
1.0,
which
includes
the
following
assumptions:

S
The
worst­
case
estimate
of
imazapyr
in
the
top
one­
foot
of
the
water
column
in
a
treated
waterbody
is
550
ppb.
Assume
that
100%
of
this
concentration
is
available
for
ingestion;

S
Ingestion
rate:
0.05
L/
hr;

S
Exposure
duration:
2
hrs/
day
for
non­
competitive
adult
and
child
swimmers;

S
Body
weight:
70
kg
for
adults,
29
kg
for
children
(
mean
figure
from
SWIMODEL)
and
15
kg
for
toddlers;

S
Body
surface
area:
20,670
cm2
for
adult
and
14,580
cm2
for
toddler/
child
swimmers
(
mean
figures
from
SWIMODEL);
and
S
Permeability
coefficient
(
K
p
):
5.85
x
10­
5
cm/
hr
(
where
K
ow
=
1.3
{
MRID
45119707},
molecular
weight
of
imazapyr
acid
=
261.3).

C
Postapplication
residential
risks
are
based
on
maximum
application
rates
or
values
specified
in
the
SOPs
For
Residential
Exposure
Assessment.

C
The
Jazzercize
approach
is
the
basis
for
the
dermal
transfer
coefficients
as
described
in
HED's
Series
875
guidelines,
SOPs
For
Residential
Exposure
Assessment,
and
the
1999
FIFRA
SAP
Overview
document.

3.2.3
Residential
Postapplication
Exposure
and
Noncancer
Risk
Estimates
Noncancer
risks
were
calculated
using
the
Margin
of
Exposure
(
MOE)
approach,
which
is
a
ratio
of
the
body
burden
to
the
toxicological
endpoint
of
concern.
Exposures
were
calculated
by
considering
the
potential
sources
of
exposure
(
i.
e.,
TTRs
on
turf),
then
calculating
dermal
and
nondietary
ingestion
exposures.
The
major
difference
with
residential
risk
assessments
is
that
the
uncertainty
factor
which
defines
the
level
of
risk
concern
also
has
to
consider
application
of
the
additional
FQPA
safety
factor.
In
the
case
of
imazapyr,
the
FQPA
factor
is
1X.
Therefore,
the
overall
uncertainty
factor
applied
to
imazapyr
for
residential
postapplication
risk
assessments
is
100
which
is
based
on
the
FQPA
safety
factor
of
1X
along
with
the
100
applied
for
inter­
species
extrapolation
(
10x)
and
intra­
species
sensitivity
(
10x).
Page
47
of
63
Dermal
exposures
and
risks
from
turf
uses
were
calculated
in
the
same
manner
as
described
above
in
Section
2.2.2.
Along
with
calculating
these
dermal
exposures,
other
aspects
of
the
turf
scenarios
involved
calculating
dose
from
non­
dietary
ingestion.
The
algorithms
used
for
each
type
of
calculation
which
have
not
been
previously
addressed
in
Section
2.2.3
are
presented
below.

Dermal
Exposure
from
Treated
Turf
(
adult
and
toddler)

The
approach
used
to
calculate
the
dermal
exposures
that
are
attributable
to
exposure
from
contacting
treated
lawns
is:

ADD
=
(
TTRt
*
ET
*
TC
*
DA
*
CF1)
/
BW
Where:
ADD
=
average
daily
dose
(
mg/
kg/
day);
TTRt
=
turf
transferable
residue
on
day
"
0"
(
µ
g/
cm2
);
ET
=
exposure
time
(
2
hr/
day);
TC
=
transfer
coefficient
(
14,500
cm2/
hr
for
adults
and
5,200
cm2/
hr
for
toddlers);
DA
=
dermal
absorption
factor;
CF1
=
weight
unit
conversion
factor
to
convert
:
g
units
to
mg
for
the
daily
exposure
(
0.001
mg/:
g);
and
BW
=
body
weight
(
70
kg
for
adults
and
15
kg
for
toddlers).

Nondietary
Ingestion
Exposure
From
Treated
Turf:
Nondietary
ingestion
exposure
from
treated
turf
were
calculated
using
the
following
equations.
These
values
were
then
used
to
calculate
MOEs.

Hand­
to­
mouth
Transfer
of
Pesticide
Residues
on
Turf
(
toddler)

The
approach
used
to
calculate
the
nondietary
ingestion
exposures
that
are
attributable
to
handto
mouth
behavior
on
treated
turf
is:

ADD
=
(
TTRt
*
SA
*
FQ
*
ET
*
SE
*
CF1)
/
BW
Where:
ADD
=
average
daily
dose
(
mg/
kg/
day);
TTRt
=
turf
transferable
residue
on
day
"
0"
(
µ
g/
cm2
);
SA
=
surface
area
of
the
hands
(
20
cm2/
event);
FQ
=
frequency
of
hand­
to­
mouth
activity
(
20
events/
hr);
ET
=
exposure
time
(
2
hr/
day);
SE
=
extraction
by
saliva
(
50%);
CF1
=
weight
unit
conversion
factor
to
convert
µ
g
units
in
the
DFR
value
to
mg
for
the
daily
exposure
(
0.001
mg/
µ
g);
and
BW
=
body
weight
(
15
kg).
Page
48
of
63
Object­
to­
mouth
Transfer
of
Pesticide
Residues
on
Turf
(
toddler)

The
approach
used
to
calculate
exposures
that
are
attributable
to
object­
to­
mouth
behavior
on
treated
turf
that
is
represented
by
a
child
mouthing
on
a
handful
of
turf
is:

ADD
=
(
TTRt
*
IgR*
CF1)
/
BW
Where:
ADD
=
average
daily
dose
(
mg/
kg/
day);
TTRt
=
turf
transferable
residue
on
day
"
0"
(
µ
g/
cm2);
IgR
=
ingestion
rate
of
grass
(
25
cm2/
day);
CF1
=
weight
unit
conversion
factor
to
convert
the
µ
g
of
residues
on
the
grass
to
mg
to
provide
units
of
mg/
day
(
1E­
3
mg/
µ
g);
and
BW
=
body
weight
(
15
kg).

Incidental
Ingestion
of
Soil
from
Pesticide­
Treated
Areas
(
toddler)

The
approach
used
to
calculate
exposures
that
are
attributable
to
soil
ingestion
is:

ADD
=
(
SRt
*
IgR
*
CF1)
/
BW
Where:
ADD
=
average
daily
dose
(
mg/
kg/
day);
SRt
=
soil
residue
on
day
"
0"
(
0.0022
µ
g/
g);
IgR
=
ingestion
rate
of
soil
(
100
mg/
day);
CF1
=
weight
unit
conversion
factor
to
convert
the
µ
g
of
residues
on
the
soil
to
grams
to
provide
units
of
mg/
day
(
1E­
6
g/
µ
g);
and
BW
=
body
weight
(
15
kg).

and
SRt
=
TTRt
*
F
*
CF2
Where:
TTRt
=
turf
transferable
residue
on
day
"
0"
(
µ
g/
cm2);
F
=
fraction
of
ai
available
in
uppermost
cm
of
soil
(
1
fraction/
cm);
and
CF2
=
volume
to
weight
unit
conversion
factor
to
convert
the
volume
units
(
cm3)
to
weight
units
for
the
SR
value
(
U.
S.
EPA,
1992)
(
0.67
cm3/
g
soil).

Incidental
Ingestion
of
Granules
from
Pesticide­
Treated
Areas
(
toddler)

The
approach
used
to
calculate
exposures
that
are
attributable
to
granule
ingestion
is:

ADD
=
(
IgR
*
F
*
CF1)/
BW
Where:
ADD
=
average
daily
dose
(
mg/
kg/
day);
IgR
=
ingestion
rate
of
granules
(
0.3
g/
day);
Page
49
of
63
F
=
fraction
of
ai
in
dry
formulation
(
unitless);
CF1
=
weight
unit
conversion
factor
to
convert
the
g
units
in
the
ingestion
rate
value
to
mg
for
the
daily
exposure
(
1000
mg/
g);
and
BW
=
body
weight
(
15
kg).

3.2.4
Residential
Postapplication
Noncancer
Risk
Summary
HED
has
addressed
residential
postapplication
exposures
to
imazapyr
using
the
standard
set
of
scenarios
that
are
prescribed
in
current
guidance.
There
are
many
issues
associated
with
the
development
of
these
scenarios
and,
in
general,
residential
exposure
methods.
Readers
should
refer
to
the
guidance
documents
that
are
presented
above
for
further
information
concerning
the
development
of
scenarios
for
residential
exposure
assessment
purposes.
The
uncertainty
factors
are
similar
to
those
applied
to
the
residential
handler
assessments
described
above
(
i.
e.,
100
for
short­
term
exposures).

Post­
application
Turf
Exposure
and
Risk:

Adult
short­
term
postapplication
risk
is
below
HED's
level
of
concern
(
i.
e.,
the
MOE
is
greater
than
100)
for
the
turfgrass
scenario.
Table
14
presents
the
postapplication
MOE
for
adults
after
turfgrass
(
recreational
areas)
applications
of
imazapyr.

Table
14:
Adult
Residential
Risk
Estimates
for
Postapplication
Exposure
to
Imazapyr
Exposure
Scenario
Route
of
Exposure
Application
Ratea
MOE
on
Day
of
Application
Outdoors
Residential
Turf
(
High
Contact
Activities)
Dermal
1.5
lb
ae/
acre
720
Toddler
(
3
year
old)
short­
term
postapplication
risks
were
calculated
following
the
turf
uses
of
imazapyr.
Table
15
presents
a
summary
of
the
MOE
estimates
for
toddlers.
Short­
term
MOEs
from
dermal
and
incidental
oral
exposures
to
treated
turf
(
in
products
labeled
for
direct
application
to
turf)
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100).

Table
15:
Toddler
Residential
Risk
Estimates
for
Postapplication
Exposure
to
Imazapyr
Exposure
Scenario
Route
of
Exposure
Application
Rate
MOE
on
Day
of
Application
Outdoors
Hand
to
Mouth
Activity
on
Turf
Oral
1.5
lb
ae/
acre
11,000
Object
to
Mouth
Activity
on
Turf
Oral
1.5
lb
ae/
acre
45,000
Incidental
Soil
Ingestion
Oral
1.5
lb
ae/
acre
3,300,000
Incidental
Ingestion
of
Granules
Oral
1.5
lb
ae/
acre
2,500
Turf
(
High
Contact
Activities)
Dermal
1.5
lb
ae/
acre
430
Page
50
of
63
Post­
application
Swimmer
Exposure
and
Risk:
This
section
excerpted
from
Imazapyr
in/
on
Rangeland
and
Aquatic
Sites.
Health
Effects
Division
(
HED)
Risk
Assessment.
Dana
Vogel.
DP
Barcode
DP291393.
July
17,
2003.

A
post­
application
assessment
is
included
for
adults,
toddlers,
and
children
swimming
in
treated
waters
immediately
after
an
application,
since
the
proposed
label
does
not
prohibit
swimming
in
treated
waters.
The
registrant
submitted
a
field
dissipation
study
using
Arsenal
®
(
MRID:
45119707)
applied
at
a
rate
of
1.6
lb
ae/
A.
At
four
test
sites
(
Florida
and
Missouri),
the
highest
imazapyr
concentration
observed
was
approximately
196
ppb
in
Missouri;
however,
at
the
Florida
sites,
the
Environmental
Fate
and
Effects
Division
(
EFED)
noted
that
the
initial
concentrations
of
imazapyr
were
only
about
one­
third
of
the
amount
applied.
Accounting
for
this
observation,
the
highest
imazapyr
concentration
could
have
approached
500
ppb.
Therefore,
HED
estimated
a
worst­
case
concentration
for
imazapyr
in
the
top
one­
foot
of
the
water
column
in
a
treated
waterbody;
this
peak
estimate
is
550
ppb
and
is
anticipated
to
be
conservative.

The
exposure
assumptions
used
in
the
swimmer
assessment
are
based
on
HED's
SOP
for
Residential
Exposure
Assessments,
Draft,
December
17,
1997
and
HED's
SWIMODEL
V
1.0
(
W.
Dang
and
Versar,
27­
MAR­
1999)
for
swimming
pools
adapted
for
this
assessment.
It
should
be
noted
that
the
Residential
SOP/
SWIMODEL
assumptions
are
considered
to
be
conservative
for
use
in
assessing
the
lake/
pond
swimmer
scenario
as
explained
in
Table
16.

Table
16:
Comparison
of
Assumptions
for
Post­
Application
Swimmer
Exposure
Assessments
for
Imazapyr
Assumption
Residential
SOP
for
Swimmers
in
Pools
Arsenal
®
Application:
Post­
Application
at
Aquatic
Sites
Post­
application
concentration
100%
available
concentration
post­
application
Maximum
imazapyr
concentration
in
top
onefoot
of
water
column
is
approx.
550
ppb.
Assuming
100%
available
is
considered
conservative.

Subsequent
postapplication
Assumed
not
to
dissipate
Exposed
foliage
is
the
intended
target
of
treatments.
Any
spray
entering
water
column
is
anticipated
to
dissipate.

Duration
of
exposure
5
hours
for
competitive
adult
2
hours
for
non­
competitive
child
2
hours
assumed,
since
floating
or
emerged
weeds
will
be
present
making
competitive
swimming
(
training)
very
difficult
Inhalation
exposure
Assumed
for
pool
swimmers
No
significant
inhalation
exposure
is
anticipated.
An
inhalation
assessment
is
not
included.
Page
51
of
63
Table
17
presents
the
risk
estimates
for
post­
application
exposures
by
swimmers.
Short­
term
MOEs
from
dermal
and
incidental
oral
exposures
to
treated
lake
water
(
from
swimming
activities)
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100).

Table
17.
Post­
Application
Swimmer
Exposure
and
Risk
Assessments
for
Proposed
Use
of
Imazapyr
at
Aquatic
Sites
Exposure
Scenario
AR
(
lb
ae/
A)
Concentration
in
water
(
ppb)
Potential
Dose
Rate
(
PDR;
oral)
1
or
Absorbed
Dose
Rate
(
ADR;
dermal)
2
(
mg/
kg/
day)
Short­
term
MOE3
Incidental
Ingestion,
adult
1.5
550
(
0.55
mg/
L)
7.86
x
10­
4
320,000
Incidental
Ingestion,
child
1.90
x
10­
3
130,000
Incidental
Ingestion,
toddler
3.67
x
10­
3
68,000
Dermal,
adult
1.90
x
10­
5
>
1
x
107
Dermal,
child
3.24
x
10­
5
>
1
x
106
Dermal,
toddler
6.26
x
10­
5
>
1
x
106
1.
PDR,
incidental
oral
ingestion
=
concentration,
C
w
(
mg/
L)
x
ingestion
rate,
IgR
(
L/
hr)
x
exposure
time,
ET
(
hrs/
day)
x
1/
BW
(
adult=
70
kg;
child
=
29
kg;
toddler
=
15
kg)
2.
ADR=
concentration,
C
w
(
mg/
L)
x
dermal
surface
area
exposed,
SA
(
cm2)
x
ET
x
K
p
(
cm/
hr)
x
1/
l000
cm3
x
%
Dermal
Absorption
(
correct
to
oral
equivalent)
x
1/
BW,
where
K
p
is
estimated
as
follows:
log
K
p
=
­
2.72
+
0.71log
K
ow
­
0.0061MW;
K
ow
=
1.3
,
MW
=
261.3,
so
K
p
=
5.85
x
10­
5
cm/
hr.
3.
MOE
=
NOAEL/
PDR;
short­
term
incidental
oral
NOAEL
=
250
mg/
kg/
day
short­
term
dermal
NOAEL
=
250
mg/
kg
bw/
day.
The
level
of
concern
for
short­
term
recreational
exposures
is
for
MOEs
<
100.

Combined
Risk
Assessment
for
Residential
Postapplication
Exposure
Scenarios
HED
combines
risk
values
resulting
from
separate
postapplication
exposure
scenarios
when
it
is
likely
they
can
occur
simultaneously
based
on
the
use­
pattern
and
the
behavior
associated
with
the
exposed
population.
Table
18
presents
a
summary
of
the
combined
MOE
estimates.

The
combined
risk
assessment
was
calculated
as
follows:

Combined
MOE
=
NOAEL/(
ADD
hand­
to­
mouth
+
ADD
object­
to­
mouth
+
ADD
incidental
soil
ingestion
)

The
combined
risks
for
the
turf
spray
scenario
is
410
and
does
not
exceed
HED's
level
of
concern.
The
combined
risks
for
the
water
(
swimming)
scenario
is
64,000
and
does
not
exceed
HED's
level
of
concern.

Table
18:
Imazapyr
Residential
Scenarios
for
Combined
Risk
Estimates
Postapplication
Exposure
Scenario
Margins
of
Exposure
(
MOEs)
(
UF=
100)
Short­
Term
Oral
(
Non­
Dietary)
Total
Non­
Dietary
Risk
Page
52
of
63
Toddler
Turf
­
sprays
(
1.5
lb
ae/
acre)
Dermal
430
410
Hand
to
Mouth
11,000
Object
to
Mouth
45,000
Incidental
Soil
Ingestion
3,300,000
Toddler
Water
(
1.5
lb
ae/
acre)
Dermal
>
1
x
106
64,000
Incidental
Ingestion
68,000
3.2.5
Summary
of
Residential
Postapplication
Risk
Concerns
and
Data
Gaps
HED
considered
exposure
scenarios
for
products
that
can
be
used
in
the
residential
environment
representing
different
segments
of
the
population
including
toddlers,
youth­
aged
children,
and
adults.
Short­
term
noncancer
MOEs
were
calculated
for
all
scenarios.
In
residential
settings,
HED
does
not
use
restricted­
entry
intervals
or
other
mitigation
approaches
to
limit
postapplication
exposures
because
they
are
viewed
as
impractical
and
not
enforceable.
As
such,
risk
estimates
on
the
day
of
application
are
the
key
concern.

Risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
less
than
100)
for
dermal
postapplication
exposures
to
adults
or
toddlers
from
turf
pesticide
treatments.
Risks
also
do
not
exceed
HED's
level
of
concern
for
nondietary
postapplication
exposures
to
toddlers
from
turf
pesticide
treatments.

HED
combines
risks
resulting
from
different
routes
of
exposures
to
individuals
when
it
is
likely
they
can
occur
simultaneously
based
on
the
use
pattern
and
the
behavior
associated
with
the
exposed
population.
For
imazapyr,
HED
has
combined
risk
values
(
i.
e.,
MOEs)
for
different
routes
of
exposures
associated
with
the
turf
scenario
(
dermal,
hand­
to­
mouth,
object­
to­
mouth,
and
soil
ingestion).
These
are
typically
added
together
when
pesticides
are
used
on
turf,
because
it
is
logical
they
can
co­
occur.
For
the
turf
uses,
dermal
and
hand­
to­
mouth
exposures
are
the
key
contributors
to
the
overall
estimates.
All
of
these
combined
risks
are
below
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
greater
than
100).

Risks
do
not
exceed
HED's
level
of
concern
(
i.
e.,
the
MOEs
are
less
than
100)
for
dermal
postapplication
exposures
to
adults
or
toddlers
from
swimming
in
imazapyr
treated
water.
Risks
also
do
not
exceed
HED's
level
of
concern
for
nondietary
postapplication
exposures
to
toddlers
from
swimming
in
imazapyr
treated
water.

3.2.6
Recommendations
For
Refining
Residential
Postapplication
Risk
Assessment
In
order
to
refine
this
residential
assessment,
data
on
actual
use
patterns
including
rates,
timing,
and
the
kinds
of
tasks
that
are
required
to
better
characterize
imazapyr
risks.
Page
53
of
63
Appendix
A:
Occupational
Handler
Exposures
Page
54
of
63
Appendix
A/
Table
A1:
Sources
of
Exposure
Data
Used
In
The
Occupational
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
(
Number)
Data
Source
Standard
Assumptions
(
8­
hr
work
day)
a
Commentsb,
c
Mixer/
Loader
Descriptors
Mixing/
Loading
Liquid
Formulations
(
1a
through
1c)
PHED
V1.1
Aerial:
400
acres
for
aquatic
sites,
350
acres
for
corn,
forest
sites,
and
areas
grazed
for
hay,

and
100
for
non­
crop
areas;

Groundboom:
80
acres
for
corn,

forest
sites,
areas
grazed
for
hay,

and
for
non­
crop
areas;

Rights
of
Way:
80
acres
for
forest
sites
and
non­
crop
areas
Baseline:
Dermal,
hand,
and
inhalation
=
acceptable
grades.
Hands
=
53
replicates;
Dermal
=
72
to
122
replicates;
and
Inhalation
=
85
replicates.
High
confidence
in
hand,
dermal,
and
inhalation
data.
No
protection
factor
was
needed
to
define
the
unit
exposures.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Hands
=
acceptable
grades.
Hands
=
59
replicates.
High
confidence
in
hand
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Hands,
dermal,
and
inhalation
=
acceptable
grades.
Hands
=
31
replicates;
Dermal
=
16
to
22
replicates;
and
Inhalation
=
27
replicates.
High
confidence
in
hand,
dermal,
and
inhalation
data.
Gloves
were
used
coupled
with
engineering
controls
since
empirical
data
without
gloves
were
not
available
and
back
calculation
of
gloves
to
a
no
glove
scenario
is
believed
to
give
erroneously
high
estimates.

Mixing/
Loading
Dry
Flowable
Formulations
(
2a
through
2c)
PHED
V1.1
Aerial:
350
acres
for
corn
and
of
100
for
non­
crop
areas;

Groundboom:
80
acres
for
corn
and
for
non­
crop
areas;

Rights
of
Way:
80
acres
for
noncrop
areas
Baseline:
Dermal,
hand,
and
inhalation
=
AB
grades.
Hands
=
7
replicates;
Dermal
=
16
to
26
replicates,
and
Inhalation
=
23
replicates.
Low
confidence
in
the
dermal/
hands
data
due
to
the
low
number
of
hand
replicates.
High
confidence
in
inhalation
data.
No
protection
factor
was
needed
to
define
the
unit
exposure
value.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Hand
=
AB
grades.
Hands
=
21
replicates.
High
confidence
in
hand
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Dermal
and
hands
=
AB
grades.
Inhalation
=
all
grades.
Dermal
=
6
to
15
replicates;
Hands
=
5
replicates;
and
Inhalation
=
15
replicates.
Low
confidence
in
hand,
dermal,
and
inhalation
data.

Loading
Granular
Formulations
(
3a
through
3b)
PHED
V1.1
Aerial:
100
acres
for
non­
crop
areas;

Tractor
Drawn
Spreader:
80
acres
for
non­
crop
areas
Baseline:
Dermal
=
ABC
grades;
Hand
=
all
grades;
and
Inhalation
=
AB
grades.
Dermal
=
25
to
59
replicates;
Hands
=
10
replicates;

and
Inhalation
=
58
replicates.
Low
confidence
in
the
dermal/
hands
data
due
to
the
poor
replicate
quality
of
the
hand
replicates
and
low
replicate
number.
High
confidence
in
inhalation
data.
No
protection
factor
was
needed
to
define
the
unit
exposure
value.

PPE:
Dermal
=
ABC
grades
and
Hand
=
AB
grades.
Dermal
=
33
to
78
replicates
and
Hands
=
45
replicates.
Medium
confidence
in
the
dermal/
hands
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
The
same
data
are
used
as
for
baseline
coupled
with
a
98%
protection
factor
to
account
for
the
use
of
an
engineering
control
(
e.
g.,
closed
mixing/
loading
system).

Applying
Descriptors
Applying
Sprays
via
Fixedwing
Aircraft
(
4)
PHED
V1.1
400
acres
for
aquatic
sites,
350
acres
for
corn,
forest
sites,
and
areas
grazed
for
hay,
and
100
for
non­
crop
areas;
Engineering
Controls:
Dermal
and
hands
=
AB
grade
and
Inhalation
=
ABC
grade.
Dermal
=
20
to
28
replicates;
Hands
=
34
replicates;
and
Inhalation
=
23
replicates.
High
confidence
in
dermal
and
hand
data.
Medium
confidence
in
inhalation
data.
No
protection
factor
was
needed
to
define
the
unit
exposure
value.

EPA
has
no
data
for
this
scenario,
other
than
enclosed
cockpits
 
the
engineering
control.
Appendix
A/
Table
A1:
Sources
of
Exposure
Data
Used
In
The
Occupational
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
(
Number)
Data
Source
Standard
Assumptions
(
8­
hr
work
day)
a
Commentsb,
c
Page
55
of
63
Applying
Granulars
via
Fixed­
wing
Aircraft
(
5)
PHED
V1.1
100
acres
for
non­
crop
areas
Engineering
Controls:
Dermal
=
C
grade
and
Hands
and
Inhalation
=
all
grades.
Dermal
=
9
to
13
replicates;
Hands
=
4
replicates;

and
Inhalation
=
13
replicates.
Low
confidence
in
dermal,
hand,
and
inhalation
data
due
to
inadequate
replicate
number
and
poor
grade
quality.
No
protection
factor
was
needed
to
define
the
unit
exposure
value.

EPA
has
no
data
for
this
scenario,
other
than
enclosed
cockpits
 
the
engineering
control.

Applying
Sprays
via
Groundboom
Sprayer
(
6)
PHED
V1.1
80
acres
for
corn,
forest
sites,

areas
grazed
for
hay,
and
for
noncrop
areas
Baseline:
Dermal,
hand,
and
inhalation
=
AB
grades.
Dermal
=
23
to
42
replicates;
Hands
=
29
replicates;
and
Inhalation
=
22
replicates.
High
confidence
in
hand,
dermal,
and
inhalation
data.
No
protection
factors
were
needed
to
define
the
unit
exposure
values.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Hands
=
ABC
grades.
Hands
=
21
replicates.
Medium
confidence
in
hand
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Dermal
and
Hands
=
ABC
grade.
Inhalation
=
AB
grades.
Dermal
=
20
to
31
replicates;
Hands
=
16
replicates;

and
inhalation
=
16
replicates.
Medium
confidence
in
the
hand
and
dermal
data.
High
confidence
in
inhalation
data.
No
protection
factor
needed
to
define
the
unit
exposure
value.
Protective
gloves
not
used.

Applying
Sprays
via
Rights
of
Way
Sprayer
(
7)
PHED
V1.1
80
acres
for
forest
sites
and
noncrop
areas
Baseline:
Dermal
=
ABC
grades.
Hand
=
AB
grades.
Inhalation
=
A
grades.
Dermal
=
4
to
20
replicates;
Hands
=
16
replicates;
and
Inhalation
=
16
replicates.
Low
confidence
in
dermal
and
hand
data.
High
confidence
in
inhalation
data.
No
protection
factor
was
needed
to
define
the
unit
exposure
value.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Hands
=
AB
grades.
Hands
=
4
replicates.
Low
confidence
in
hand
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Applying
Granulars
via
Tractor
Drawn
Spreader
(
8)
PHED
V1.1
80
acres
for
non­
crop
areas
Baseline:
Dermal,
hand,
and
inhalation
=
AB
grades.
Dermal
=
1
to
5
replicates;
Hands
=
5
replicates;
and
Inhalation
=
5
replicates.

Low
confidence
in
hand,
dermal,
and
inhalation
data
due
to
low
replicates.
No
protection
factors
were
needed
to
define
the
unit
exposure
values.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Dermal
=
AB
grades.
Low
confidence
in
dermal
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).
Gloved
hand
replicates
are
unavailable
for
this
scenario.
The
only
way
to
estimate
gloved
hand
exposure
is
to
reduce
the
"
no
glove"
hand
value
by
90%.

Engineering
Controls:
Dermal,
hands,
and
inhalation
=
AB
grade.
Dermal
=
2
to
27
replicates;
Hands
=
24
replicates;
and
Inhalation
=
37
replicates.
Low
confidence
in
the
dermal
data
due
to
inadequate
replicate
number.
High
confidence
in
hand
and
inhalation
data.

No
protection
factor
needed
to
define
the
unit
exposure
value.
Protective
gloves
not
used.
Appendix
A/
Table
A1:
Sources
of
Exposure
Data
Used
In
The
Occupational
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
(
Number)
Data
Source
Standard
Assumptions
(
8­
hr
work
day)
a
Commentsb,
c
Page
56
of
63
Flagging
Descriptors
Flagging
for
Aerial
Spray
Applications
(
9)
PHED
V1.1
350
acres
for
corn,
forest
sites,

and
areas
grazed
for
hay
Baseline:
Dermal,
hands,
and
inhalation
=
AB
grades.
Dermal
=
18
to
28
replicates;
Hands
=
30
replicates;
and
Inhalation
=
28
replicates.
High
confidence
in
dermal,
hand,
and
inhalation
data.
No
protection
factor
was
required
to
calculate
unit
exposures.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.

Hand
=
AB
grades.
Hands
=
6
replicates.
Low
confidence
in
hand
data
due
to
the
small
number
of
replicates.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
The
same
data
are
used
as
for
baseline
coupled
with
a
98%
protection
factor
to
account
for
the
use
of
an
engineering
control
(
e.
g.,
sitting
in
a
vehicle).

Flagging
for
Aerial
Granular
Applications
(
10)
PHED
V1.1
100
for
non­
crop
areas
Baseline:
Dermal,
hands,
and
inhalation
=
AB
grades.
Dermal
=
18
to
28
replicates;
Hands
=
30
replicates;
and
Inhalation
=
28
replicates.
High
confidence
in
dermal,
hand,
and
inhalation
data.
No
protection
factor
was
required
to
calculate
unit
exposures.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.

Hand
=
AB
grades.
Hands
=
6
replicates.
Low
confidence
in
hand
data
due
to
the
small
number
of
replicates.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
The
same
data
are
used
as
for
baseline
coupled
with
a
98%
protection
factor
to
account
for
the
use
of
an
engineering
control
(
e.
g.,
sitting
in
a
vehicle).

Mixing/
Loading/
Applying
Descriptors
Mixing/
Loading/
Applying
Liquids
via
Low
Pressure
Handwand
(
11)
PHED
V1.1
5
acres
for
non­
crop
areas
Baseline:
Hands
=
all
grades;
dermal
and
inhalation
=
ABC
grades.
Dermal
=
9
to
80
replicates;
Hands
=
70
replicates;
and
Inhalation
=
80
replicates.
Medium
confidence
in
inhalation
data.
Low
confidence
in
dermal
and
hand
data.
No
protection
factor
was
needed
to
define
the
unit
exposure
values.

PPE:
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.

Hand
=
10
replicates.
Hands=
ABC
grades
Low
confidence
in
hand
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
halfface
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Mixing/
Loading/
Applying
Dry
Flowables
via
Low
Pressure
Handwand
(
12)
PHED
V1.1
5
acres
for
non­
crop
areas
Data
from
Mixing/
Loading/
Applying
Liquids
via
Low
Pressure
Handwand
were
used
as
a
surrogate
for
this
scenario.
Appendix
A/
Table
A1:
Sources
of
Exposure
Data
Used
In
The
Occupational
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
(
Number)
Data
Source
Standard
Assumptions
(
8­
hr
work
day)
a
Commentsb,
c
Page
57
of
63
Mixing/
Loading/
Applying
Granulars
via
Push
Type
Spreader
(
13)
ORETF
Chemical
Handler
Exposure
Studies
5
acres
for
non­
crop
areas
Baseline:
Dermal
data
=
AB
grade
and
20
replicates.
Inhalation
=
AB
grade
and
20
replicates.
Moderate
to
high
confidence
in
inhalation
data.

PPE:.
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Gloved
hand
=
20
replicates.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Mixing/
Loading/
Applying
Granulars
via
Pump
Feed
Backpack
Spreader
(
14)
MRID#
451672­
01;

Temik
rangefinder
of
5
to
10
acres
for
non­
crop
areas
Baseline:
Dermal
data
=
AB
grade
and
12
replicates.
Inhalation
=
AB
grade
and
12
replicates.
Moderate
to
high
confidence
in
inhalation
data.

PPE:.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Mixing/
Loading/
Applying
Granulars
via
Gravity
Feed
Backpack
Spreader
(
15)
MRID
#
452507­
01;

Fipronil
rangefinder
of
5
to
10
acres
for
non­
crop
areas
Baseline:
Dermal
data
=
A
grade
and
18
replicates.
Inhalation
=
A
grade
and
18
replicates.
Moderate
to
high
confidence
in
inhalation
data.
PPE:.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Mixing/
Loading/
Applying
Liquids
via
Handgun
Sprayer
(
ORETF
data)
(
16)
ORETF
Chemical
Handler
Exposure
Studies
10
acres
for
aquatic
sites,
5
acres
for
non­
crop
areas
Baseline:
Dermal
data
=
B
grade
and
15
replicates.
The
only
empirical
data
available
are
based
on
the
use
of
chemical­
resistant
gloves.
It
is
generally
not
appropriate
to
back­
calculate
a
non­
glove
hand
exposure.
Inhalation
=
B
grade
and
15
replicates.
Moderate
to
high
confidence
in
inhalation
data.

PPE:.
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Gloved
hand
=
15
replicates.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Mixing/
Loading/
Applying
Dry
Flowables
via
Handgun
Sprayer
(
ORETF
data)
(
17)
ORETF
Chemical
Handler
Exposure
Studies
5
acres
for
non­
crop
areas
Baseline:
Dermal
data
=
B
grade
and
15
replicates.
The
only
empirical
data
available
are
based
on
the
use
of
chemical­
resistant
gloves.
It
is
generally
not
appropriate
to
back­
calculate
a
non­
glove
hand
exposure.
Inhalation
=
B
grade
and
15
replicates.
Moderate
to
high
confidence
in
inhalation
data.

PPE:.
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Gloved
hand
=
15
replicates.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.
Appendix
A/
Table
A1:
Sources
of
Exposure
Data
Used
In
The
Occupational
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
(
Number)
Data
Source
Standard
Assumptions
(
8­
hr
work
day)
a
Commentsb,
c
Page
58
of
63
Mixing/
Loading/
Applying
Water
Soluble
Bags
via
Handgun
Sprayer
(
ORETF
data)
(
18)
ORETF
Chemical
Handler
Exposure
Studies
5
acres
for
non­
crop
areas
Baseline:
Dermal
data
=
B
grade
and
15
replicates.
The
only
empirical
data
available
are
based
on
the
use
of
chemical­
resistant
gloves.
It
is
generally
not
appropriate
to
back­
calculate
a
non­
glove
hand
exposure.
Inhalation
=
B
grade
and
15
replicates.
Moderate
to
high
confidence
in
inhalation
data.

PPE:.
The
same
dermal
data
are
used
as
for
baseline
coupled
with
a
50%
protection
factor
to
account
for
an
additional
layer
of
clothing.
Gloved
hand
=
15
replicates.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Mixing/
Loading/
Applying
Liquids
via
Backpack
Sprayers
(
19)
PHED
V1.1
5
acres
for
aquatic
sites
Baseline:
The
only
empirical
data
available
are
based
on
the
use
of
chemical­
resistant
gloves.
It
is
generally
not
appropriate
to
back­
calculate
a
non­
glove
hand
exposure.
Inhalation
=
AB
grade
and
11
replicates.
Low
confidence
in
inhalation
data.

PPE:.
Dermal
data
=
AB
grades
and
9
to
11
replicates.
Gloved
hand
=
C
grades
and
11
replicates.
Low
confidence
in
dermal
and
hand
data.
A
respirator
protection
factor
of
5
is
applied
to
estimate
the
use
of
a
quarter­
face
respirator
(
dust/
mist
filtering
only).
A
respirator
protection
factor
of
10
is
applied
to
estimate
the
use
of
a
half­
face
negative
pressure
respirator
or
a
powered
air
purifying
respirator
(
dust/
mist
filtering
and/
or
organic
vapor­
removing).

Engineering
Controls:
Not
considered
feasible
for
this
exposure
scenario.

Mixing/
Loading/
Applying
Liquids
via
Tree
Injection
Equipment
(
20)
No
data
is
available
for
this
scenario.

a
All
Standard
Assumptions
are
based
on
an
8­
hour
work
day
as
estimated
by
HED.

b
All
handler
exposure
assessments
in
this
document
are
based
on
the
"
Best
Available"
data
as
defined
by
the
HED
SOP
for
meeting
Subdivision
U
Guidelines
(
i.
e.,
completing
exposure
assessments).
Best
available
grades
are
assigned
to
data
as
follows:
matrices
with
A
and
B
grade
data
(
i.
e.,
Acceptable
Grade
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:

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.

c
PHED
grading
criteria
do
not
reflect
overall
quality
of
the
reliability
of
the
assessment.
Sources
of
the
exposure
factors
should
also
be
considered
in
the
risk
Page
59
of
63
Appendix
A/
Table
A2:
Unit
Exposure
Values
Used
In
The
Occupational
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
Baseline
Dermal
Unit
Exposure
(
mg/
lb
ai)
Baseline
Inhalation
Unit
Exposure
(
ug/
lb
ai)
PPE­
G
Dermal
Unit
Exposure
(
mg/
lb
ai)
PPE­
G,
DL
Dermal
Unit
Exposure
(
mg/
lb
ai)
80%
PPE­
R
Inhalation
Unit
Exposure
(
ug/
lb
ai)
90%
PPE­
R
Inhalation
Unit
Exposure
(
ug/
lb
ai)
Eng
Con
Dermal
Unit
Exposure
(
mg/
lb
ai)
Eng
Con
Inhalation
Unit
Exposure
(
ug/
lb
ai)

Mixer/
Loader
Mixing/
Loading
Liquids
2.9
1.2
0.023
0.017
0.24
0.12
0.0086
0.083
Mixing/
Loading
Dry
Flowables
0.066
0.77
0.066
0.047
0.154
0.077
0.0098
0.24
Loading
Granulars
0.0084
1.7
0.0069
0.0034
0.34
0.17
0.00017
0.034
Applicator
Applying
Liquid
Sprays
via
Aerial
Equipment
No
Data
No
Data
No
Data
No
Data
No
Data
No
Data
0.005
0.068
Applying
Granulars
via
Aerial
Equipment
No
Data
No
Data
No
Data
No
Data
No
Data
No
Data
0.0017
1.3
Applying
Liquid
Sprays
via
Groundboom
Equipment
0.014
0.74
0.014
0.011
0.148
0.074
0.005
0.043
Applying
Liquid
Sprays
via
Rights
of
Way
Equipment
1.3
3.9
0.39
0.29
0.78
0.39
Not
Feasible
Not
Feasible
Applying
Granulars
via
Tractor
Drawn
Spreader
0.0099
1.2
0.0072
0.0042
0.24
0.12
0.0021
0.22
Flagger
Flagging
for
Liquid
Sprays
via
Aerial
Equipment
0.011
0.35
No
Data
0.01
0.07
0.035
0.00022
0.043
Flagging
for
Granulars
via
Aerial
Equipment
0.0028
0.15
No
Data
0.0016
0.03
0.015
0.000056
0.22
Mixer/
Loader/
Applicator
Mixing/
Loading/
Applying
Liquids
with
Low
Pressure
Handwand
100
30
0.43
No
Data
6
3
Not
Feasible
Not
Feasible
Mixing/
Loading/
Applying
Dry
Flowables
with
Low
Pressure
Handwand
100
30
0.43
No
Data
6
3
Not
Feasible
Not
Feasible
Loading/
Applying
Granulars
via
Push
Type
Spreader
(
ORETF)
0.35
7.3
0.22
0.11
1.46
0.73
Not
Feasible
Not
Feasible
Loading/
Applying
Granulars
via
Pumpfeed
Backpack
Applicator
(
MRID#
451672­
01;

Temik)
No
Data
4.2
0.1
No
Data
0.84
0.42
Not
Feasible
Not
Feasible
Loading/
Applying
Granulars
via
Gravity­
feed
Backpack
Applicator
(
MRID
#
452507­
01;

Fipronil
study)
No
Data
44
0.6
No
Data
8.8
4.4
Not
Feasible
Not
Feasible
Mixing/
Loading/
Applying
Liquids
with
a
Handgun
Sprayer
(
ORETF
data)
No
Data
1.8
0.45
0.25
0.36
0.18
Not
Feasible
Not
Feasible
Appendix
A/
Table
A2:
Unit
Exposure
Values
Used
In
The
Occupational
Imazapyr
Handler
Exposure
And
Risk
Calculations
Page
60
of
63
Mixing/
Loading/
Applying
Liquids
with
a
Backpack
Sprayer
No
Data
30
2.5
No
Data
6
3
0.0086
0.083
Mixing/
Loading/
Applying
Dry
Flowables
with
a
Handgun
Sprayer
(
LCO
ORETF
data)
No
Data
22
0.58
0.33
4.4
2.2
Not
Feasible
Not
Feasible
Mixing/
Loading/
Applying
Water
Soluble
Bags
with
Handgun
Sprayer
(
ORETF
data)
No
Data
7.2
0.64
0.37
1.44
0.72
Not
Feasible
Not
Feasible
Mixing/
Loading/
Applying
Liquids
with
an
Injector
No
Data
No
Data
No
Data
No
Data
No
Data
No
Data
Not
Feasible
Not
Feasible
Page
61
of
63
Appendix
B:
Residential
Handler
Exposures
Page
62
of
63
Appendix
B/
Table
B1:
Sources
of
Exposure
Data
Used
In
The
Residential
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
(
Number)
Data
Source
Standard
Assumptions
(
8­
hr
work
day)
a
Commentsb,
c
Mixer/
Loader/
Applicator
Descriptors
Mixing/
Loading/
Applying
Liquids
with
Low
Pressure
Handwand
(
1)
ORETF
Chemical
Handler
Exposure
Studies
1,000
sq
ft
for
driveways,
parking
areas,
brick
walls,
gravel
pathways,
patios,
along
sidewalks
and
bare
ground
Baseline:
Dermal,
inhalation,
and
hands
=
A
grade.
Dermal,
inhalation,
and
hands
=
20
replicates
each.
High
confidence
in
all
data.

Mixing/
Loading/
Applying
Liquids
with
a
Watering
Can
(
using
ORETF
hose­
end
sprayer
data)
(
2)
ORETF
Chemical
Handler
Exposure
Studies
1,000
sq
ft
for
driveways,
parking
areas,
brick
walls,
gravel
pathways,
patios,
along
sidewalks
and
bare
ground
Baseline:
Dermal,
inhalation,
and
hands
=
A
grade.
Dermal,
inhalation,
and
hands
=
20
replicates
each.
High
confidence
in
all
data.

PPE
and
Engineering
Controls
data
are
not
required
for
this
assessment.

a
All
Standard
Assumptions
are
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
the
PHED
SOP
for
meeting
Subdivision
U
Guidelines
(
i.
e.,
completing
exposure
assessments).
Best
available
grades
are
assigned
to
data
as
follows:
matrices
with
A
and
B
grade
data
(
i.
e.,
Acceptable
Grade
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:

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.

c
PHED
grading
criteria
do
not
reflect
overall
quality
of
the
reliability
of
the
assessment.
Sources
of
the
exposure
factors
should
also
be
considered
in
the
risk
management
decision.
Page
63
of
63
Appendix
B/
Table
B2:
Unit
Exposure
Values
Used
In
The
Residential
Imazapyr
Handler
Exposure
And
Risk
Calculations
Exposure
Scenario
Crop
or
Target
Baseline
Dermal
Unit
Exposure
(
mg/
lb
ai)
Baseline
Inhalation
Unit
Exposure
(
ug/
lb
ai)

Mixer/
Loader/
Applicator
Mixing/
Loading/
Applying
Liquids
with
Low
Pressure
Handwand
driveways,
parking
areas,
brick
walls,
gravel
pathways,

patios,
along
sidewalks
and
bare
ground
38
2.7
Mixing/
Loading/
Applying
Liquids
with
a
Watering
Can
(
using
ORETF
residential
hose­
end
data)
driveways,
parking
areas,
brick
walls,
gravel
pathways,

patios,
along
sidewalks
and
bare
ground
11
17