Document ID: EPA-HQ-OPP-2005-0479-0003
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2005-12-28T05:00Z

Page
1
of
33
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
OFFICE
OF
PREVENTION,
PESTICIDES,
AND
TOXIC
SUBSTANCES
WASHINGTON,
D.
C.
20460
September
6,
2005
MEMORANDUM
SUBJECT:
DICAMBA:
Occupational
and
Residential
Exposure
and
Risk
Assessment
for
the
Reregistration
Eligibility
Decision
(
RED)
Document
[
PC
Code
029801,
DP
Barcode
D317701]

FROM:
Timothy
C.
Dole,
Industrial
Hygienist
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

THROUGH:
Matthew
Lloyd,
Industrial
Hygienist
And
Whang
Phang,
Branch
Senior
Scientist
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

TO:
Christine
Olinger,
Risk
Assessor
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

And
Kendra
Tyler,
Chemical
Review
Manager
Special
Review
and
Reregistration
Division
(
SRRD)

Attached
is
the
Occupational
and
Residential
Exposure
and
Risk
Assessment
document
for
the
Dicamba
RED
Chapter.

Expo
SAC
Reviewers:
Steve
Weiss
and
Kelly
Orourke
Page
2
of
33
Table
of
Contents
Executive
Summary
3
1.01
Background
Information
6
1.1
Purpose
and
Criteria
for
Conducting
Exposure
Assessments
6
1.2
Toxicological
Endpoints
6
1.3
Incident
Reports
8
1.4
Summary
of
Use
Patterns,
Formulations
and
Application
Methods
8
2.0
Occupational
and
Residential
Exposures
and
Risks
13
2.1
Occupational
Handler/
Applicator
Exposures
&
Risks
13
2.1.1
Exposure
Scenarios
13
2.1.2
Exposure
Assumptions
and
Data
Sources
13
2.1.3
Exposure
and
Risk
Estimates
16
2.1.4
Risk
Characterization
16
2.2
Occupational
Post
Application
Exposures
&
Risks
18
2.2.1
Exposure
Scenarios
18
2.2.2
Exposure
Data
Sources,
Assumptions
and
Transfer
Coefficients
18
2.2.3
Exposure
and
Risk
Estimates
20
2.2.4
Risk
Characterization
20
2.3
Residential
Applicator
Exposure
and
Risks
21
2.3.1
Exposure
Scenarios,
Data
Sources
and
Assumptions
21
2.3.2
Exposure
and
Risk
Estimates
22
2.3.3
Risk
Characterization
22
2.4
Residential
Turf
Post
Application
Exposure
and
Risks
22
2.4.1
Exposure
Scenarios,
Data
Sources
and
Assumptions
22
2.4.2
Exposure
and
Risk
Estimates
28
2.4.3
Risk
Characterization
29
2.5
Resdential
Turf
Granular
Ingestion
Exposure
and
Risks
31
3.0
References
32
4.0
Glossary
of
Terms
33
Appendices
A
­
Standard
Formulas
Used
for
Calculating
Dicamba
Occupational
and
Residential
Exposures
B
­
Occupational
Handler
Exposure
Data
and
Risk
Calculations
for
Dicamba
C
­
Occupational
Post­
Application
Risks
of
Dicamba
D
­
Residential
Handler
Exposure
Data
and
Risk
Calculations
for
Dicamba
E
­
Dicamba
Turf
Transferable
Residue
Data
F
­
Residential
Turf
Post
Application
Risk
Assessment
for
Dicamba
Page
3
of
33
Executive
Summary
Dicamba
Use
Description
Based
upon
the
Dicamba
Use
Closure
Memo,
there
are
registered
products
of
dicamba
intended
for
both
occupational
and
residential
uses.
The
registered
occupational
uses
include
small
grains,
corn,
sorghum,
sugarcane,
sod
farms,
pastures,
rangeland
and
rights
of
way
areas.
Residential
uses
include
broadcast
and
spot
treatment
on
golf
courses
and
lawns.

Toxicology
Endpoints:

Dicamba
is
of
low
to
moderate
acute
toxicity
(
i.
e.
Tox
Category
III
or
IV)
via
the
oral,
inhalation
or
dermal
routes
of
exposure.
Dicamba
is
an
eye
and
skin
irritant
(
Tox
Category
II);
however,
it
is
not
a
skin
sensitizer.

The
following
endpoints
were
used
for
assessing
dicamba
occupational
and
residential
risks:

C
An
oral
LOAEL
of
300
mg/
kg/
day
from
an
acute
neurotoxicity
study
in
rats
in
which
clinical
signs
of
neurotoxicity
were
observed
at
the
lowest
dose
tested
of
300
mg/
kg/
day.
This
LOAEL
is
applicable
for
acute
dermal
and
incidental
oral
exposures
for
children
and
acute
dermal
exposures
for
adults.

C
An
oral
NOAEL
of
45
mg/
kg/
day
from
a
multigeneration
reproduction
study
in
rats
in
which
decreased
pup
growth
was
observed
at
the
LOAEL
of
136
mg/
kg/
day.
This
NOAEL
is
applicable
to
short­,
intermediate­,
and
long­
term
incidental
oral,
dermal
and
inhalation
exposures
for
the
general
population
and
workers.

C
A
dermal
absorption
factor
of
15
percent
was
estimated
for
converting
dermal
exposures
to
oral
equivalent
doses.

The
target
MOE
for
occupational
exposures
is
100,
which
includes
the
standard
safety
factors
of
10X
for
intraspecies
variability
(
i.
e.
differences
among
humans)
and
10X
for
interspecies
variability
(
differences
between
humans
and
animals).
The
target
MOE
for
acute
residential
exposures
is
300
because
it
includes
an
additional
factor
of
3
to
account
for
the
lack
of
a
NOAEL
in
the
acute
neurotoxicity
study.
The
target
MOE
for
short
term
residential
exposures
is
100.

Occupational
Handler/
Applicator
Exposure
and
Risk
Estimates:

The
MOEs
for
occupational
exposures
were
calculated
for
short/
intermediate
term
dermal
and
inhalation
exposures
using
standard
assumptions
and
unit
exposure
data.
The
unit
exposure
data
were
generally
taken
from
the
Pesticide
Handlers
Exposure
Database
(
PHED)
and
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
studies
for
professional
lawn
care
operators.
All
of
the
mixer/
loader
MOEs
exceed
the
target
of
100
with
single
layer
PPE
(
i.
e.
baseline
clothing
with
gloves)
and
are
not
of
concern.
The
MOEs
for
applicators
are
above
100
with
baseline
or
single
layer
PPE
.
The
MOEs
for
the
mixer/
loader/
applicators
are
acceptable
with
single
layer
PPE
and
the
MOEs
for
the
flaggers
are
acceptable
with
baseline
PPE.
The
labels
typically
require
baseline
Page
4
of
33
clothing
with
water
proof
gloves.

Data
Used
for
Turf
Post
Application
Exposure
Assessment
There
are
three
turf
transferable
residue
studies
that
were
submitted
by
the
Broadleaf
Turf
Herbicide
TFR
Task
Force
and
there
was
an
additional
study
that
was
submitted
by
Novartis
Crop
Protection.
All
of
the
studies
were
reviewed
by
HED
and
were
found
to
meet
most
of
the
series
875
guidelines
for
postapplication
exposure
monitoring.
The
day
0
TTR
values
ranged
from
0.8
to
1.5
percent
of
the
application
rate
with
an
average
of
1.1
percent
(
n
=
9)
and
maximum
TTR
values
ranged
from
1.1
to
2.6
with
an
average
of
1.6
(
n=
9).
In
many
cases
the
maximum
TTR
values
occurred
a
few
hours
after
application.
The
half
lives
ranged
from
0.33
days
at
sites
with
rain
to
1.8
days
at
dry
sites.

A
maximum
TTR
value
of
2.6
percent
of
the
application
rate
was
derived
from
the
Vanquish
Study
(
MRID
449590­
01)
and
was
used
for
assessing
acute
exposures.
A
7
day
average
TTR
of
0.55
percent
of
the
application
rate
was
derived
from
the
California
site
of
MRID
450331­
01
which
had
a
half
life
of
1.8
days.
The
seven
day
average
TTR
was
used
for
assessing
short
term
exposures.

Post­
Application
Occupational
Exposure
and
Risk
Estimates:

Post
application
exposure
to
re­
entry
workers
may
occur
because
dicamba
can
be
applied
over
the
top
to
some
of
the
labeled
crops.
The
exposures
include
irrigation
and
scouting
of
small
grains
and
harvesting
of
sod
farm
turf.
The
exposures
were
assessed
using
standard
assumptions
and
maximum
label
rates.
The
TTR
data
was
used
to
assess
exposures
on
sod
farm
turf
and
default
assumptions
were
used
for
the
other
crops
that
did
not
have
residue
data.
All
of
the
post
application
MOEs
are
above
the
target
MOE
of
100
on
Day
0.

Residential
Applicator
Exposure
and
Risk
Estimates:

The
residential
products
are
typically
formulated
as
dry
weed
and
feed
products
or
as
liquids
in
concentrates
or
ready
to
use
sprays.
Spot
and
broadcast
treatments
are
both
included
on
the
labels.
The
MOEs
for
residential
handlers
exposures
were
calculated
using
standard
assumptions,
maximum
label
rates
and
PHED
and
ORETF
unit
exposure
data.
The
MOEs
exceed
the
target
MOE
of
100
which
means
the
risks
are
not
of
concern.

Residential
Turf
Post
Application
Exposure
and
Risk
Estimates
The
MOEs
for
residential
turf
exposures
were
calculated
using
the
TTR
data,
maximum
label
rates
and
the
Residential
SOPs.
MOEs
were
calculated
for
acute
exposures
using
the
maximum
TTR
value
of
2.6
percent
of
the
application
rate
along
with
the
appropriate
acute
endpoint.
MOEs
for
short
term
exposures
were
calculated
using
the
seven
day
average
TTR
because
the
short
term
NOAEL
was
based
upon
effects
observed
during
the
multi­
generation
reproduction
study
(
decreased
pup
weight
gain)
which
did
not
occur
until
after
several
days
of
exposure.

The
acute
MOEs
exceed
the
target
MOE
of
300
and
the
short
term
MOEs
exceed
the
target
Page
5
of
33
MOE
of
100.
This
means
that
the
acute
and
short
term
risks
are
not
of
concern.

Residential
Turf
Granule
Ingestion
Exposure
and
Risk
Estimates
The
risks
for
toddlers
ingesting
granules
that
have
been
applied
to
residential
turf
were
assessed
using
a
standard
method
as
outlined
in
the
Residential
SOPs.
The
percent
ai
in
granular
products
was
assumed
to
be
in
the
range
of
0.1
to
1.0
percent
based
upon
the
labels
listed
in
OPPIN.
The
MOEs
were
calculated
using
the
NOAEL
of
300
mg/
kg/
day
and
ranged
from
1,500
to
15,000
which
exceeds
the
target
MOE
of
300.
This
means
that
the
risks
for
toddler
exposures
from
granular
ingestion
are
not
of
concern.

Risk
Characterization
The
calculation
of
acute
MOEs
using
a
maximum
TTR
value
for
toddler
turf
post
application
exposure
represents
a
policy
change,
because
the
maximum
TTR
values
were
previously
only
used
to
calculate
short
term
MOEs.
The
dicamba
risk
assessment
team
decided
that
the
previous
approach
would
greatly
overestimate
the
short
term
risks,
because
the
short
term
incidental
oral
and
dermal
endpoints
were
based
upon
effects
that
would
only
occur
after
several
days
of
exposure.
The
team
also
decided
that
the
single
day
exposures
as
represented
by
the
maximum
TTR
values
would
be
more
appropriately
assessed
using
the
acute
dietary
endpoint.
The
short
term
exposures
were
assessed
using
the
seven
day
average
TTR
values
because
the
endpoints
occurred
after
several
days
of
exposure
and
because
the
TTR
data
were
collected
during
a
seven
day
time
period.

The
actual
use
rates
of
dicamba
are
typically
less
than
the
maximum
label
rates
because
dicamba
is
usually
mixed
with
other
herbicides
(
e.
g.
2,4­
D)
to
improve
weed
control.

Only
a
few
dicamba
products
are
formulated
as
wettable
powders
and
most
of
these
products
are
packaged
in
water
soluble
bags
for
turf
use.

Some
of
the
end
use
product
labels
require
waterproof
gloves
instead
of
chemical
resistant
gloves.
It
is
not
known
if
these
gloves
provide
adequate
protection
for
dicamba.
Page
6
of
33
1.0
Background
Information
1.1
Purpose
and
Criteria
for
Conducting
Exposure
Assessments
Occupational
and
residential
exposure
and
risk
assessments
are
required
for
an
active
ingredient
if:
(
1)
certain
toxicological
criteria
are
triggered
and
(
2)
there
is
potential
exposure
to
handlers
during
use,
or
to
field
workers
entering
treated
areas
after
application
is
completed.
Dicamba
(
4­
chloro­
2­
methylphenoxy
acetic
acid;
CAS
#
94­
74­
6)
meets
both
criteria.
There
is
potential
exposure
to
handlers
and
field
workers
from
agricultural
site
applications
of
dicamba.
In
addition,
the
general
public
may
be
exposed
to
dicamba
during
or
after
application
to
turf.

Many
of
the
dicamba
products
also
contain
other
registered
active
ingredient
herbicides
including
other
phenoxy
herbicides
such
as
2,4­
D.
These
ingredients
are
not
addressed
in
this
risk
assessment.

1.2
Toxicological
Endpoints
A
summary
of
the
acute
toxicity
data
is
included
in
Table
1.
This
data
indicates
that
dicamba
is
of
low
to
moderate
toxicity
(
i.
e.
Tox
Category
III
or
IV)
via
the
oral,
inhalation
or
dermal
routes
of
exposure.
Dicamba
is
an
eye
and
skin
irritant
(
Tox
Category
II),
however,
it
is
not
a
skin
sensitizer.

Table
1
­
Acute
Toxicity
of
Dicamba
Guideline
No.
Study
Type
MRID
NO.
Results
Toxicity
Category
870.1100
870.1200
870.1300
870.2400
870.2500
870.2600
Acute
Oral
Acute
Dermal
Acute
Inhalation
Primary
Eye
Irritation
Primary
Skin
Irritation
Dermal
sensitization
00078444
00241584
00263861
00241584
00237955
00263861
LD50
=
2740
mg/
kg
LD50
>
2000
mg/
kg
LC50
=
>
5.3
mg/
L
Irritant
Irritant
Non
sensitizer
III
III
IV
II
II
N/
A
The
toxicological
endpoints
used
to
complete
occupational
and
residential
exposure
assessments
are
summarized
in
Table
2.
A
21
day
dermal
toxicity
study
was
available
but
it
was
not
used
to
assess
dermal
exposures
because
it
did
not
evaluate
reproductive
effects.
A
dermal
absorption
factor
of
15
percent
was
derived
from
a
comparison
of
the
NOAEL
of
1000
mg/
kg/
day
from
the
21
day
dermal
toxicity
study
in
rabbits
with
the
NOAEL
of
150
mg/
kg/
day
from
the
rat
oral
developmental
study.
Page
7
of
33
Table
2
­
Dicamba
Toxicological
Endpoints
Used
for
Occupational
and
Residential
Risk
Assessment
Exposure
Scenario
Dose
or
Factor
Used
in
Risk
Assessment
Study
and
Toxicological
Effects
Acute
Dietary
(
all
populations)
Oral
LOAEL
=
300
mg/
kg/
day
Acute
Neurotoxicity
Study
in
Rats
LOAEL
=
300
mg/
kg/
day
(
LDT)
based
on
clinical
signs
of
neurotoxicity.

Incidental
Oral
Short/
Intermediate/
Long
Term
NOAEL=
45
mg/
kg/
day
Multi­
generation
Reproduction
Study
in
Rats.
LOAEL
=
136
mg/
kg/
day
based
on
impaired
pup
growth.

Dermal
Short/
Intermediate/
Long
Term
Same
as
above
Same
as
above
Inhalation
Short/
Intermediate/
Long
Term
Same
as
above
Same
as
above
Cancer
Classification:
Not
likely
to
be
carcinogenic
to
humans
Dermal
Absorption
Factor
15
percent
of
the
oral
dose
Comparison
of
NOAEL
of
1000
mg/
kg/
day
from
the
21
day
dermal
toxicity
study
in
rabbits
with
the
NOAEL
of
150
mg/
kg/
day
from
the
rat
oral
developmental
study.

Target
MOE
for
Occupational
Exposures
100
Dermal
100
Inhalation
Includes
standard
uncertainty
factors
of
10
and
10
for
intraspecies
variability
and
interspecies
extrapolation.

Target
MOE
for
Acute
Residential
Exposures
300
All
routes
Includes
additional
factors
of
3
to
account
for
the
lack
of
a
NOAEL.

Target
MOE
for
Short
Term
Residential
Exposures
100
All
routes
*
Since
an
oral
NOAEL
was
selected,
a
dermal
absorption
factor
should
be
used
in
route
to
route
extrapolation.
*
Inhalation
absorption
is
assumed
to
be
equivalent
to
oral
absorption
(
100
percent
default
value).
Page
8
of
33
1.3
Incident
Report
The
incident
report
was
prepared
under
a
separate
memo
by
Monica
Spann,
M.
P.
H.
and
Jerome
Blondell,
PhD.
of
the
Office
of
Pesticide
Programs.
The
incident
report
was
complicated
by
the
fact
that
dicamba
is
rarely
used
as
a
herbicide
by
itself
and
is
usually
mixed
with
other
chlorophenoxy
herbicides,
like
2,4­
D.
Only
those
incidents
involving
products
with
dicamba
as
the
sole
active
ingredient
in
a
product
were
considered.
There
was
only
a
single
report
in
the
Incident
Data
System
which
occurred
when
a
contractor
at
the
formulating
plant
was
treated
for
minor
eye
irritation
resulting
from
dicamba
flaked
dust
falling
into
his
eye.
The
flake
operation
was
started
while
the
contractor
was
installing
a
pipe
bracket
under
a
line
below
the
operating
equipment.

Poison
Control
Center
Data
for
the
years
1993
through
2003
indicate
that
there
were
only
24
occupational
exposures
to
dicamba
that
is
too
few
to
warrant
a
detailed
analysis.
Of
these
24
cases,
3
had
a
moderate
medical
outcome
and
1
was
considered
a
major
medical
outcome.
The
one
major
outcome
case
was
a
15
year
old
who
was
exposed
in
the
eye
and
experienced
blurred
vision,
irritation,
non­
reactive
pupils,
and
visual
defect.
This
case
should
not
have
been
classified
as
major
unless
the
poison
specialist
anticipated
the
effect
would
be
permanent
and
the
duration
of
effect
for
this
case
was
listed
as
unknown.
The
poison
control
data
indicated
that
there
were
146
non­
occupational
(
i.
e.
residential)
exposure
cases
and
13
of
these
cases
were
classified
as
a
moderate
medical
outcome
with
primary
symptoms
of
eye
irritation,
corneal
abrasion,
coughing,
and
difficulty
breathing.
One
case
with
major
medical
outcome
was
a
16
year­
old
with
chest
pain,
dysrhythmia,
tachycardia
(
fast
pulse),
multiple
seizures,
and
coma
after
inhalation.
However,
there
were
no
other
cases
with
such
serious
symptoms
among
the
146
exposures.

No
reports
of
dicamba
poisoning
were
reported
in
California
from
1982
through
2003.
It
was
not
possible
to
search
the
National
Pesticide
Information
Center
for
calls
associated
with
products
containing
only
dicamba.
Out
of
5,899
reported
cases
in
the
NIOSH
SENSOR
program
from
1998­
2003,
none
involved
dicamba
as
a
sole
active
ingredient.

The
incident
report
concluded
that
"
There
were
too
few
reports
of
ill
effects
from
exposure
to
dicamba
in
the
available
data
bases
to
draw
conclusions
about
likely
effects.
Reigart
and
Roberts
(
1999)
state
that
dicamba
can
be
moderately
irritating
to
skin
and
respiratory
tract.
This
is
consistent
with
reported
symptoms
from
Poison
Control
Centers.
No
recommendations
are
made
based
on
the
limited
information
available."

1.4
Summary
of
Use
Patterns,
Formulations
and
Application
Methods
Uses
Based
upon
the
Dicamba
Use
Closure
Memo,
there
are
registered
products
of
dicamba
intended
for
both
occupational
and
residential
site
applications.
The
registered
agricultural
uses
include
small
grains
(
i.
e.
barley,
oats,
rye
and
wheat),
corn,
sorghum,
sugarcane,
pastures,
rangeland
and
sod
farm
turf.
Residential
uses
include
broadcast
and
spot
treatment
on
turf.

Based
upon
available
pesticide
survey
usage
information
for
the
years
1998­
2003,
the
Page
9
of
33
Biological
and
Economic
Effects
Division
(
BEAD)
of
EPA
estimates
that
total
annual
domestic
usage
of
dicamba
is
approximately
5.65
million
pounds
active
ingredient
(
ai).
A
listing
of
the
use
sites
ranked
by
the
amount
used
is
given
in
Table
3.

Table
3
­
Screening
Level
Estimates
of
Agricultural
Uses
of
Dicamba
Use
Site
Amount
Used
(
pounds)
Percent
of
Total
Used
Corn
Wheat
Pasture
and
Rangeland
Sorghum
Hay
Sugarcane
Barley
Oats
Cotton
Soybeans
Total
of
Above
3,500,000
1,300,000
600,000
100,000
50,000
30,000
30,000
20,000
10,000
10,000
5,650,000
61.9%
23.0%
10.6%
1.8%
0.9%
0.5%
0.5%
0.4%
0.2%
0.2%
100%

Source:
SLUA
Report
for
Dicamba,
EPA
BEAD,
6/
20/
01.

Mode
of
Action
and
Targets
Controlled
Dicamba
is
a
highly
selective
herbicide
mainly
used
for
post
emergent
control
of
certain
broadleaf
weeds
and
woody
plants.
It
is
an
auxin
agonist
that
is
readily
translocated
symplastically
and
apoplastically
with
accumulation
in
meristemic
regions
of
the
plant.
Sensitive
plants
exhibit
rapid
uncontrolled
growth
characterized
by
twisting
and
curling
of
stems
and
petioles,
stem
elongation
and
swelling
and
leaf
cupping.
Weed
control
is
generally
achieved
in
5
to
7
days.

Formulation
Types
and
Percent
Active
Ingredient
According
to
the
EPA
OPPIN
tracking
system,
as
of
01/
24/
05,
there
were
approximately
434
active
dicamba
products
formulated
from
6
different
forms.
A
listing
of
these
forms
is
included
in
Table
4.
The
acid,
dimethylamine
and
sodium
salt
ester
forms
of
dicamba
have
the
most
products.
The
commercial
and
agricultural
products
are
generally
formulated
as
liquids,
standard
granules
and
water
dispersible
granules.
One
dimethylamine
product
(
228­
283)
is
a
wettable
powder
and
is
labeled
for
professional
applicator
use
on
turf.
One
sodium
salt
product
(
241­
359)
is
a
wettable
powder
that
is
packaged
in
water
soluble
bags
and
it
is
labeled
for
use
on
clearfield
corn
seed
hybrids.
The
residential
products
are
typically
formulated
as
granular
weed
and
feed
formulations
or
as
liquids
in
concentrates
or
ready
to
use
sprays.
Two
dimethylamine
residential
products
are
listed
as
dusts
in
OPPIN,
however,
the
labels
indicate
that
they
are
weed
and
feed
formulations
applied
with
broadcast
spreaders
which
suggests
that
they
are
actually
granular
formulations.
Page
10
of
33
Table
4
­
Dicamba
Forms
and
Number
of
Labels
Dicamba
Form
PC
CODE
Number
of
Labels
Predominant
Formulations
Other
Formulations
(
Registration
Number)

Acid
029801
143
Liquids
and
granules
None
Dimethylamine
salt(
DMA)
029802
251
Liquids
and
granules
Dusts
(
228­
343,
228­
229)
Wettable
Powder
(
228­
283)

Sodium
salt
029806
21
Liquids
and
Water
Dispersible
Granules
Wettable
Powder
in
Water
Soluble
Bags
(
241­
359)

Potassium
salt
129043
10
Liquids
None
DGA
salt
128931
5
Liquids
None
Isopropyl
amine
128944
4
Liquid
None
Application
Rates,
Timing
and
Frequency
of
Applications
Typically
one
application
is
made
per
growing
season.
The
label
required
spray
volumes
for
ground
applications
range
from
20
gallons
for
most
crops
to
100
gallons
per
acre
for
vine
and
brush
control.
Dicamba
can
be
applied
over
the
top
to
the
labeled
crops.

The
application
rates
are
included
in
Table
5
and
are
given
in
terms
of
acid
equivalent
(
ae).
The
average
application
rates
are
typically
lower
than
the
label
application
rates
because
dicamba
is
typically
tank
mixed
with
other
herbicides.
Page
11
of
33
Table
5
­
Dicamba
Application
Rates
Crop
or
Site
Acid
Equivalent
Application
Rates
Per
Application
(
lb
ae/
acre)

Application
Rates
per
Smart
Meeting1
Application
Rates
per
All
Registrant
Labels2
Average
Rate3
Percent
Crop
Treated4
Outlier
Labels
Asparagus
0.5
0.5
0.33
5
Barley
N/
A
0.25
foliar
0.5
Preplant
0.08
5
Corn
0.5
0.5
0.19
20
Cotton
0.25
0.25
0.25
<
1
Fallow
Land
2.0
2.0
0.12
ND
Grass
for
Seed
2.0
1.0
ND
ND
Hay
1.0
2.0
ND
ND
Right
of
Way
(
ROW)
Areas
2.0
2.0
Most
Labels
8.7
Outlier
Labels
ND
NA
Veteran
10G
SAN
845H*

Oat
0.125
0.125
foliar
0.5
preplant
ND
5
Millet
0.125
0.125
ND
ND
Pasture
and
Rangeland
1.0
2.0
Most
Labels
8.7
Outlier
Labels
0.25
<
1
Veteran
10G
SAN
845H
Rye
N/
A
0.5
ND
ND
Sod
Farms
1.0
1.0
ND
ND
Sorghum
0.25
0.275
foliar
0.5
pre­
emergent
0.16
5
Soybean
2.0
2.0
0.21
<
1
Sugar
Cane
2.0
2.0
Most
Labels
2.8
Outlier
Label
0.18
15
7969­
140
Turf,
Golf
Courses
1.0
ND
NA
Turf,
Lawns
2.0
ND
NA
Wheat
0.25
0.10
10
Notes
1.
As
listed
in
the
Dicamba
Smart
Meeting
of
11/
04/
2004.
2.
Based
upon
the
master
label
spreadsheets
produced
by
BEAD.
3.
Usage
Report
in
Support
of
the
Dicamba
(
029801)
Reregistration,
BEAD,
7/
29/
05
4.
Screening
Level
Estimates
of
Agricultural
Uses
of
Dicamba,
BEAD,
7/
14/
04
*
The
master
label
spreadsheet
has
this
rate
listed
as
0.877
lb
ae/
acre
which
is
an
apparent
typographical
error.
Page
12
of
33
Application
Methods
The
dicamba
labels
allow
ground
and
aerial
application,
but
do
not
allow
chemigation.
Most
of
the
dicamba
applications
(
97%)
are
made
by
ground
and
only
a
small
percentage
(
3%)
are
made
by
air.
Most
of
the
ground
applications
are
made
by
the
grower.
A
listing
of
application
methods
and
amounts
of
acreage
treated
per
8
hour
day
is
included
in
Table
6.

Table
6
­
Dicamba
Application
Methods
Application
Method
Typical
Crops
Treated
Treated
Acreagea
Groundboom
Small
Grains,
Corn,
Sugarcane
Golf
Course
Turf
200
40
Fixed
Wing
Aircraft
Small
Grains,
Corn,
Sugarcane
1200
Right
of
Way
(
ROW)
Sprayer
Broadcast
Weed
Control
­
20
gallons
per
acre
Spot
Treatment
Brush
Control
­
10
gallons/
acre
50b
10c
Turfgun
(
mix/
load/
apply)
Turfgun
(
mixer/
loader
for
20
person
crew)
Turfgun
(
apply
only)
Turf
5
100d
5
Backpack
Sprayer
­
Mix/
Load/
Apply
Spot
Treatment
2e
Backpack
Sprayer
(
apply
only)
Backpack
Sprayer
(
mixer/
loader
for
10
person
crew)
Forest
Sites
4f
40g
Tractor
Drawn
Broadcast
Spreader
Turf
40
Push
Type
Broadcast
Spreader
Turf
5
a.
Based
upon
HED
Exposac
SOP
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture",
Revised
July
5,
2000
b.
Based
upon
1000
gallons
of
spray
applied
per
day
from
SOP
#
9
divided
by
an
estimated
spray
volume
of
20
GPA.
c.
Based
upon
1000
gallons
of
spray
applied
per
day
from
SOP
#
9
divided
by
an
estimated
spray
volume
of
100
GPA.
d.
Based
upon
a
mixer
loader
at
a
central
location
supporting
a
crew
of
20
PCOs.
e.
Based
upon
40
gallons
of
spray
applied
per
day
from
SOP
#
9
divided
by
an
estimated
spray
volume
of
20
GPA.
f.
Based
upon
the
acreage
treated
in
CA
DPR
HS­
1769
normalized
to
an
8
hour
day.
The
spray
volume
was
25
GPA.
g.
Based
upon
a
mixer/
loader
supporting
a
crew
of
10
backpack
applicators.

2.0
Occupational
and
Residential
Exposures
and
Risks
As
discussed
above,
dicamba
is
used
both
in
the
agricultural
and
residential
environment.
The
risks
from
mixing,
loading
and
applying
dicamba
in
the
agricultural
environment
are
discussed
in
section
2.1.
Post
application
exposures
and
risks
for
agriculture
are
discussed
in
section
2.2.
Exposures
and
risks
for
homeowners
(
i.
e.
residential)
are
discussed
in
sections
2.3
and
2.4.
Page
13
of
33
2.1
Occupational
Handler/
Applicator
Exposures
&
Risks
2.1.1
Exposure
Scenarios
Based
upon
the
application
methods
listed
in
Table
6,
the
following
exposure
scenarios
were
assessed.

Mix/
Load
Wettable
Powder
Mix/
Load
Water
Dispersible
Granules
Mix/
Load
Liquid
Formulations
Load
Granules
Aerial
Application
Groundboom
Application
Turfgun
Application
Backpack
application
Right
of
Way
Application
Broadcast
Spreader
Application
Mix/
Load/
Apply
Liquids
with
a
Backpack
Sprayer
Mix/
Load/
Apply
Wettable
Powder
with
a
Turfgun
Mix/
Load/
Apply
Wettable
Powder
with
a
Water
Dispersible
Granules
Mix/
Load/
Apply
Liquids
with
a
Turfgun
Load/
Apply
Granules
with
a
Push
Cyclone
Flag
Aerial
Application
2.1.2
Occupational
Handler
Exposure
Assumptions
and
Data
Sources
Exposure
Assumptions
The
following
assumptions
and
factors
were
used
in
order
to
complete
the
exposure
and
risk
assessments
for
occupational
handlers/
applicators:
°
The
average
work
day
was
8
hours.
°
The
daily
acreages
treated
were
taken
from
EPA
Science
Advisory
Council
for
Exposure
Standard
Operating
Procedure
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture,"
Revised
July
5,
2000.
These
values
are
listed
in
Table
6.

C
The
application
rates
are
the
maximum
rates
as
listed
in
the
Dicamba
Use
Closure
Memo.

C
A
body
weight
of
70
kg
was
assumed
because
the
endpoint
is
not
gender
specific.

C
The
inhalation
absorption
rate
is
100%.

C
Baseline
PPE
includes
long
sleeve
shirts,
long
pants
and
no
gloves
or
respirator.

C
Single
Layer
PPE
includes
baseline
PPE
with
chemical
resistant
gloves.

C
Double
Layer
PPE
includes
coveralls
over
single
layer
PPE.

C
PF5
indicates
a
filtering
facepiece
respirator
(
i.
e.
a
dustmask)
with
a
protection
factor
of
5
when
properly
fitted.

C
PF10
indicates
a
half
mask
elastomeric
facepiece
respirator
with
a
protection
factor
of
10
when
properly
fitted
and
used
with
appropriate
cartridges.

C
Only
closed
cockpit
airplanes
are
used
for
aerial
application.

C
Airplane
pilots
do
not
wear
chemical
resistant
gloves.
Page
14
of
33
Handler
Exposure
Data
Sources
The
handler
exposure
data
were
taken
from
the
Pesticide
Handler
Exposure
Database
(
PHED),
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
and
the
California
Department
of
Pesticide
Regulation
(
CA
DPR).
The
PHED
data
were
used
primarily
for
the
large
scale
agricultural
and
forestry
scenarios
and
the
ORETF
data
were
used
for
lawn
care
scenarios.
The
CA
DPR
data
were
used
for
the
backpack
applicator
forest
site
preparation
scenario
where
multiple
applicators
are
supplied
by
a
nurse
tank.
A
summary
of
each
data
source
is
provided
below.

PHED
Data
PHED
was
designed
by
a
task
force
of
representatives
from
the
US
EPA,
Health
Canada,
the
California
Department
of
Pesticide
Regulation,
and
member
companies
of
the
American
Crop
Protection
Association.
PHED
is
a
software
system
consisting
of
two
parts
 
a
database
of
measured
exposure
values
for
workers
involved
in
the
handling
of
pesticides
under
actual
field
conditions
and
a
set
of
computer
algorithms
used
to
subset
and
statistically
summarize
the
selected
data.
Currently,
the
database
contains
values
for
over
1,700
monitored
individuals
(
i.
e.,
replicates).
The
distribution
of
exposure
values
for
each
body
part
(
e.
g.,
chest,
upper
arm)
is
categorized
as
normal,
lognormal,
or
"
other"
(
i.
e.,
neither
normal
nor
lognormal).
A
central
tendency
value
is
then
selected
from
the
distribution
of
the
exposure
values
for
each
body
part.
These
values
are
the
arithmetic
mean
for
normal
distributions,
the
geometric
mean
for
lognormal
distributions,
and
the
median
for
all
"
other"
distributions.
Once
selected,
the
central
tendency
values
for
each
body
part
are
composited
into
a
"
best
fit"
exposure
value
representing
the
entire
body.

The
unit
exposure
values
calculated
by
PHED
generally
range
from
the
geometric
mean
to
the
median
of
the
selected
data
set.
To
add
consistency
and
quality
control
to
the
values
produced
from
this
system,
the
PHED
Task
Force
has
evaluated
all
data
within
the
system
and
has
developed
a
set
of
grading
criteria
to
characterize
the
quality
of
the
original
study
data.
The
assessment
of
data
quality
is
based
upon
the
number
of
observations
and
the
available
quality
control
data.
These
evaluation
criteria
and
the
caveats
specific
to
each
exposure
scenario
are
summarized
in
Table
B2
of
Appendix
B.
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
used
to
ensure
consistency
in
exposure
assessments.

Unit
exposure
values
were
calculated
in
PHED
using
the
following
protection
factors
for
PPE:
second
layer
of
clothing
=
50%
PF
for
dermal
exposure
to
the
body,
chemically
resistant
gloves
90%
PF
for
dermal
exposure
to
the
hands,
dust
mask
80%
PF
for
inhalation
exposure
and
half
face
cartridge
respirator
=
90%
PF
for
inhalation.
Engineering
controls
are
assigned
a
protection
factor
of
90%
to
98%
depending
upon
the
type
of
engineering
controls
selected.
Page
15
of
33
ORETF
Data
Handler
exposure
data
generated
by
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
were
used
for
assessing
the
lawn
care
operator
scenarios.
These
studies
are
summarized
in
the
HED
Memorandum
"
Summary
of
HED's
Reviews
of
ORETF
Chemical
Handler
Exposure
Studies;
MRID
449722­
01",
DP
Barcode
D261948
of
April
30,
2001.
These
studies
used
Dacthal
as
a
surrogate
compound
with
a
target
application
rate
of
2.0
lbs/
ae
acre.
These
studies
were
conducted
in
accordance
with
current
Agency
guidelines
and
the
data
generated
were
of
high
quality.
These
studies
have
been
reviewed
by
HED
and
Health
Canada.

California
Department
of
Pesticide
Regulation
Exposure
Data
The
study
HS­
1769
"
Exposure
of
Hand
Applicators
to
Triclopyr
in
Forest
Settings,
1995
"
was
used
to
assess
the
exposure
of
backpack
application
for
forest
site
preparation.
This
study
was
conducted
by
the
California
Environmental
Protection
Agency,
Department
of
Pesticide
Regulation,
Worker
Health
and
Safety
Branch.

Ten
applicators
were
monitored
for
two
days
for
a
total
of
20
replicates
as
they
applied
Garlon
using
Solo
Backpack
Sprayers
which
were
filled
from
a
300
gallon
mixing
tank.
The
workers
treated
an
average
of
3.2
acres
during
each
9
hour
day
with
a
spray
volume
of
25
gallons
per
acre
and
an
application
rate
of
1.0
lb
triclopyr
ae
per
acre.
The
actual
spraying
time
was
360
minutes
per
day
with
the
remainder
of
time
spent
placing
plastic
bags
over
the
seedlings
at
the
start
of
the
workday,
removing
the
bags
at
the
end
of
the
day,
pulling
hose,
lunch/
rest
breaks
and
donning
monitoring
clothing
and
equipment.

Dermal
exposures
were
monitored
using
long
sleeve
t­
shirt
and
knee
length
socks,
hand
and
face/
neck
exposures
were
monitored
using
Chubbs
baby
wipes
and
inhalation
exposures
were
monitored
using
glass
fiber
filters.
The
workers
typically
wore
coveralls
over
the
dosimeters.
The
results
of
the
socks
were
extrapolated
to
rest
of
the
leg
by
the
Agency
using
a
factor
of
2.04
to
account
for
the
thighs.
This
factor
is
based
upon
the
surface
area
of
the
thighs,
lower
legs
and
feet
(
7510
cm2)
divided
by
the
surface
area
of
the
lower
legs
and
feet
(
3690
cm2).

The
field
recovery
was
60
+
21%
for
the
air
filters
at
100
ug/
sample,
95.9
+
8.7%
for
the
wipes
at
100
ug/
sample,
85.6
+
8.0%
for
the
sock
dosimeters
at
100
ug/
sample
and
98.2
+
5.1%
at
5000
ug/
sample
for
the
t­
shirt
dosimeters.
The
measured
results
were
above
the
fortification
levels
for
the
dermal
media
and
were
approximately
one
tenth
the
fortification
level
for
the
air
filters.
The
minimum
storage
stability
sample
recoveries
were
81
+
40%
for
the
air
filters
at
week
31,
88%
+
7.3%
for
the
socks
at
week
16,
93.2
+
2.4%
for
the
t­
shirt
at
week
10
and
93.2
+
6.5%
for
the
wipes
at
week
16.
Method
validation
data
were
also
provided
and
substantiated
the
LOQs
of
150
ug/
sample
for
the
t­
shirts,
40.1
ug/
sample
for
the
socks,
10
ug/
sample
for
the
wipes
and
1.5
ug/
sample
for
the
air
filters.
All
of
the
results
were
above
the
LOQs.

This
study
meets
Agency
guidelines
and
is
acceptable
for
use
in
risk
assessment.
The
major
limitation
is
the
use
of
knee
length
socks
to
estimate
exposures
to
the
thighs.
This
could
be
significant
because
the
majority
of
the
exposure
(
53%)
was
measured
on
the
legs,
while
lessor
amounts
were
measured
on
the
torso
(
33%),
hands
(
13%)
and
head/
face
(
2.3%).
In
a
backpack
Page
16
of
33
applicator
study
on
grasslands
in
England,
however,
86%
of
the
leg
exposure
occurred
to
the
lower
legs,
11%
occurred
on
the
thighs
and
3.5%
occurred
on
the
feet
(
Abbot
et.
al.
1983)
.
This
study
was
conducted
with
whole
body
dosimeters.
Another
limitation
is
that
4
of
the
20
inhalation
replicates
were
not
valid
because
the
sampling
pump
flowrate
decreased
by
more
than
25
percent
by
the
end
of
the
sampling
period.
The
data
from
this
study
are
summarized
in
Table
7.
In
accordance
with
ExpoSAC
Policy
the
geometric
mean
values
will
be
used
as
the
appropriate
measure
of
central
tendency
for
exposure
assessment
because
the
data
have
a
lognormal
distribution.

Table
7
­
Unit
Exposure
Values
for
Backpack
Application
in
Forest
Settings
(
CA
DPR
HS­
1769)

Unit
Exposures
per
lb
ae
handled
N
Mean
SD
Geo.
Mean1
Median
90th
Percentile
Maximum
W­
test
Result
for
Normality
Dermal
(
mg/
lb
ae)
20
8.1
7.1
6.1
6.9
15.1
30.9
Lognormal
Inhalation
(
ug/
lb
ae)
16
56
17
54
56
78
91.1
Lognormal
Note
1
­
The
values
in
bold
font
are
used
for
risk
assessment
in
accordance
with
ExpoSAC
Policy.

2.1.3
Occupational
Handler
Exposure
and
Risk
Estimates
Calculation
Methodology
and
Equations
Daily
dermal
and
inhalation
exposures
and
MOEs
were
calculated
using
standard
HED
methodology
as
described
in
Appendix
A.
A
combined
MOE
was
also
calculated
because
dicamba
exposures
from
the
dermal
and
inhalation
routes
have
the
same
toxicological
effects.
The
target
MOE
is
100
for
short/
intermediate/
long
term
exposure.
Scenarios
with
an
MOE
less
than
the
target
MOE
indicates
a
risk
of
concern
for
the
occupational
population.

Results
and
Comparison
to
Target
MOE
The
MOEs
for
handlers
are
summarized
in
Table
8
and
a
detailed
listing
is
also
included
in
Appendix
B.
All
of
the
mixer/
loader
MOEs
exceed
the
target
of
100
with
the
single
layer
PPE
and
are
not
of
concern.
The
MOEs
for
applicators
are
above
100
with
baseline
or
single
layer
PPE
.
The
MOEs
for
the
mixer/
loader/
applicators
are
acceptable
with
single
layer
PPE
and
the
MOEs
for
the
flaggers
are
acceptable
with
baseline
PPE.

2.1.4
Occupational
Handler
Risk
Characterization
The
actual
use
rates
of
dicamba
are
typically
less
than
the
maximum
label
rates
because
dicamba
is
usually
mixed
with
other
herbicides
such
as
2,4­
D
to
increase
the
spectrum
of
weeds
controlled.
Only
a
few
dicamba
products
are
formulated
as
wettable
powders
and
most
of
these
products
are
packaged
in
water
soluble
bags
that
are
used
on
turf.
Many
of
the
labels
require
waterproof
gloves
instead
of
chemical
resistant
gloves.
It
is
not
known
if
these
gloves
provide
adequate
protection.
Page
17
of
33
Table
8
­
Dicamba
Handler
Combined
MOEs
Exposure
Scenario
Crop
or
Site
Application
Rate
(
lb
ae/
acre)
Acres/
Day
Baseline
MOE
Single
Layer
MOE
Engineering
Control
MOE
Mixer/
Loader
(
M/
L)

M/
L
WP
for
Groundboom
M/
L
WP
for
Turfgun
Application
Golf
Courses
Turf
1
1
40
100
130
53
>
1000
>
1000
>
1000
>
1000
M/
L
WDG
for
Aerial
M/
L
WDG
for
Aerial
M/
L
WDG
for
Groundboom
M/
L
WDG
for
Groundboom
M/
L
WDG
for
Groundboom
M/
L
WDG
for
Turf
Gun
Fallow
Land
Corn
Fallow
Land
Corn
Golf
Courses
Turf
2
0.5
2
0.5
1
1
1200
1200
200
200
40
100
120
490
740
>
1000
>
1000
>
1000
120
490
740
>
1000
>
1000
>
1000
NA
NA
NA
NA
NA
NA
M/
L
Liquids
for
Aerial
M/
L
Liquids
for
Aerial
M/
L
Liquids
for
Aerial
M/
L
Liquids
for
Groundboom
M/
L
Liquids
for
Groundboom
M/
L
Liquids
for
Groundboom
M/
L
Liquids
for
Groundboom
M/
L
Liquids
for
Groundboom
M/
L
Liquids
for
ROW
Sprayer
M/
L
Liquids
for
Turf
Gun
M/
L
Liquids
for
Backpack
Application
Sugar
Cane
Soybeans,
RPF
Small
Grains,
Corn
Sugar
Cane
Soybean,
RPF
Small
Grains,
Corn
Sod
Farms
Golf
Courses
Right
of
Way
Areas
Turf
Forest
Site
Prep
2.8
2
0.5
2.8
2
0.5
1
1
2
1
2
1200
1200
1200
200
200
200
80
40
50
100
40
23
12
13
18
72
90
180
72
72
90
200
280
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
680
960
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
Load
Granulars
for
Broadcast
Spreader
Golf
Courses
1
40
>
1000
>
1000
>
1000
Applicator
(
APP)

Aerial
Application
Groundboom
Application
ROW
Application
Back
Pack
Application
Turfgun
Application
Broadcast
Spreader
Application
All
crops
above
All
crops
above
ROW
Forest
Site
Prep
Turf
Golf
Courses
0.5
to
2.8
0.5
to
2.8
2
1
1
1
1200
40
to
200
50
4
5
40
ND
>
1000
160
ND
ND
>
1100
ND
>
1000
500
410
>
1000
>
1000
>
1000
>
1000
ND
ND
ND
>
1000
Mixer/
Loader/
Applicator
(
M/
L/
A)

M/
L/
A
Wettable
Powder
with
Turfgun
M/
L/
A
WDG
with
Turfgun
M/
L/
A
Liquid
Flowables
with
Turfgun
M/
L/
A
Liquids
with
Backpack
Sprayer
Load/
Apply
Granules
with
a
Push
Cyclone
turf
turf
turf
ROW,
RPF
turf
1
1
1
2
1
5
5
5
4
5
ND
ND
ND
ND
ND
>
1000
>
1000
>
1000
970
>
1000
>
1000
ND
ND
ND
ND
Flagger
Flag
Aerial
Application
All
crops
above
0.5
to
2.8
1200
>
470
>
440
>
1000
Notes:

RPF
=
Rangeland,
Pastures
and
Fallow
Land
ROW
=
Rights
of
Way
MOEs
that
are
less
than
100
indicate
risks
of
concern
and
are
highlighted
in
bold
font.
Page
18
of
33
2.2
Occupational
Post
Application
Exposure
and
Risks
Post
application
dicamba
exposures
can
occur
in
the
agricultural
environment
when
workers
enter
fields
recently
treated
with
dicamba
to
conduct
tasks
such
as
scouting
and
irrigation.

2.2.1
Occupational
Post
Application
Exposure
Scenarios
Broadcast
applications
can
be
made
to
grass
crops,
such
as
cereal
grains,
which
are
tolerant
of
dicamba.
Because
dicamba
is
typically
applied
once
per
season
and
the
relevant
agricultural
scenarios
occur
for
only
a
few
weeks
per
year,
it
is
anticipated
that
dicamba
exposures
would
be
primarily
short
term
and,
more
rarely,
intermediate
term.

Potential
inhalation
exposures
are
not
anticipated
for
the
post­
application
worker
scenarios
because
of
the
low
vapor
pressure
of
dicamba
(
3.4e­
05
mm
Hg
at
25o
C),
and
the
Agency
currently
has
no
policy/
method
for
evaluating
non­
dietary
ingestion
by
workers
due
to
poor
hygiene
practices
or
smoking.
As
a
result,
only
dermal
exposures
were
evaluated
in
the
postapplication
worker
assessment.

2.2.2
Exposure
Data
Sources,
Assumptions
and
Transfer
Coefficients
Data
Sources:

There
are
three
turf
transferable
residue
(
TTR)
studies
that
were
submitted
by
the
Broadleaf
Turf
Herbicide
TFR
Task
Force.
These
studies
summarized
in
Section
2.4
­
Residential
Turf
Post
Application
Exposures
and
Risks.

Assumptions
The
following
assumptions
were
made
regarding
occupational
post
application:

C
Risks
were
assessed
using
the
maximum
rates
from
the
Dicamba
Use
Closure
Memo.

C
The
transfer
coefficients
as
listed
in
Table
9
are
from
an
interim
transfer
coefficient
policy
developed
by
HED's
Science
Advisory
Council
for
Exposure
using
proprietary
data
from
the
Agricultural
Re­
entry
Task
Force
(
ARTF)
database
(
US
EPA,
August
7,
2001).
This
policy
will
be
periodically
updated
to
incorporate
additional
information
about
agricultural
practices
in
crops
and
new
data
on
transfer
coefficients.
Much
of
this
information
will
originate
from
exposure
studies
currently
being
conducted
by
the
ARTF,

C
The
transfer
coefficients
for
turf
harvesting
and
maintenance
are
based
upon
recently
conducted
ARTF
studies
that
are
being
reviewed
by
HED.

C
The
initial
percent
of
application
rate
as
Dislodgeable
Foliar
Residue
(
DFR)
was
assumed
to
be
20%
for
all
crops
except
turf.
These
are
standard
values
used
in
the
absence
of
chemical
specific
data.

C
The
Maximum
TTR
value
(
2.6
percent
of
the
application
rate)
from
the
DMA
Treatment
at
the
Florida
site
in
the
Vanquish
Study
was
used
to
assess
risks
of
working
on
turf.
Page
19
of
33
Table
9
­
Post
Application
Exposure
Scenarios
and
Transfer
Coefficients
for
Dicamba
Crop
Label
Directions
Post
Application
Exposure
Scenarios
Transfer
Coefficient
(
cm2/
hr)

Asparagus
Apply
immediately
after
cutting.
If
spray
contacts
emerged
spears,
crooking
may
result.
Pre
Harvest
Interval
(
PHI)
=
24
hours
None1,2
Small
Grains
Barley,
Oats,
proso
millet,
triticale,
wheat
Apply
to
fall
seeded
barley
prior
to
the
jointing
stage.
Apply
to
spring
seed
barley
before
it
exceeds
the
4
leaf
stage.
Apply
to
fall
seeded
oats
prior
to
the
jointing
stage.
Apply
to
spring
seeded
oats
before
the
5
leaf
stage
is
exceeded.
Apply
to
proso
millet
at
the
2
to
5
leaf
stage.
Apply
to
fall
seeded
triticale
or
wheat
prior
to
the
jointing
stage.
Apply
to
spring
seeded
triticale
or
wheat
before
the
6
leaf
stage.

Low
Exposure
Scenarios
­
Irrigation,
scouting,
immature
plants
Medium
Exposure
Scenarios
­
Same
as
above
on
mature
plants
100
1500
Corn
Early
Post
Emergence
­
Apply
from
corn
emergence
through
5
leaf
stage
or
8
inches
tall,
whichever
comes
first.

Late
Post
Emergence
­
Apply
from
8
to
36
inch
corn
or
to
15
days
before
tassel
emergence,
whichever
comes
first.

Low
Exposure
Scenarios
­
Scouting,
weeding
immature
plants
Medium
Exposure
Scenarios
­
Scouting,
weeding
more
mature
plants
High
Exposure
Scenarios
­
Scouting,
weeding,
irrigation
mature
plants
Very
High
Exposure
Scenarios
­
Detasseling
100
400
NA
NA
Cotton
N/
A
­
Applied
as
a
preplant
treatment.
NA
Pasture,
Rangeland,
Grassland
PHI
=
7
days
None1
Sorghum
Post
Emergence
­
Apply
when
sorghum
is
in
the
3
to
5
leaf
stage,
but
before
it
is
15"
tall.
If
sorghum
is
taller
than
8"
use
drop
nozzles
and
keep
spray
off
the
foliage.

Pre­
harvest
application
(
TX
and
OK
only)
­
apply
anytime
after
soft
dough
stage
(
PHI
=
30
days)

Low
Exposure
Scenarios
­
Scouting
immature
plants
High
Exposure
Scenarios
­
Irrigation
and
scouting
mature
plants
100
1000
Soybeans
Apply
after
pods
have
reached
mature
brown
color
and
at
least
75%
leaf
drop
has
occurred
(
PHI
=
14
days)
None1
Sugarcane
Apply
before
canes
appear
for
control
of
emerged
weeds.
Apply
after
canes
emerge
and
through
canopy
closure.
When
possible
direct
sprays
beneath
the
canopy
to
minimize
the
likelihood
of
crop
damage.

Medium
Exposure
Scenarios
­
scouting
immature
plants
High
Exposure
Scenarios
­
scouting
mature
plants
1000
2000
Turf,
Sod
Farm
and
Golf
Course
Treat
when
weeds
are
young
and
actively
growing.
Do
not
apply
more
than
1.0
lb
per
season.

Low
Exposure
Scenarios
­
Mowing
High
Exposure
Scenarios
­
Transplanting,
hand
weeding
3400
6800
1.
Post
application
exposures
are
expected
to
be
minimal
due
to
application
timing
or
method.
2.
Asparagus
plants
do
not
have
foliage
(
i.
e.
ferns)
when
the
spears
are
harvested.
Page
20
of
33
Calculation
Methodology
for
Post
Application
Exposures
The
calculations
used
to
estimate
the
exposures
for
the
post­
application
scenarios
are
similar
to
those
described
previously
for
the
handler/
applicator
scenarios
and
are
described
in
Appendix
A.
Daily
dermal
exposure
is
calculated
by
multiplying
the
residue
level
(
ug/
cm2
of
leaf
area)
times
a
transfer
coefficient
(
amount
of
leaf
area
contacted
per
unit
time).
Inhalation
exposures
were
not
calculated
for
the
post­
application
scenarios
because
inhalation
exposures
have
been
shown
to
account
for
a
negligible
percentage
of
the
overall
body
burden.
This
is
particularly
true
for
dicamba
which
has
a
low
vapor
pressure
of
3.4
x
10­
5
mm
Hg
at
25oC.
.

2.2.3
Occupational
Post
Application
Exposure
and
Risk
Estimates
A
summary
of
the
worker
risks
for
short/
intermediate
term
post
application
exposures
is
given
in
Table
10
and
the
calculations
are
included
in
Appendix
C.
All
of
the
short/
intermediate
term
MOEs
are
above
100
on
Day
0
which
indicates
that
the
risks
are
not
of
concern
at
the
current
REI
of
24
hours.

Table
10
­
Dicamba
Postapplication
Worker
Risks
Crop
Transfer
Coefficient
Group
Short/
Intermediate
Term
MOE
on
Day
0
Application
Rate
(
lb
ae/
acre)
Low
Exposure
Scenarios*
Medium
Exposure
Scenarios*
High
Exposure
Scenarios*

Small
Grains
(
i.
e.
wheat)
Field/
row
crop,
low/
medium
0.50
23000
1600
NA
Corn
(
Early
Post
Emergence)
Field/
row
crop,
low/
medium
0.50
23000
N/
A
NA
Corn
(
Late
Post
Emergence)
Field/
row
crop,
low/
medium
0.25
N/
A
12000
N/
A
Sorghum
Field/
row
crop,
low/
medium
0.25
47000
12000
4700
Sugarcane
Sugarcane
2.8
N/
A
420
210
Turf
Turf
1.0
2600
N/
A
1300
*
Task
descriptions
for
each
crop
and
exposure
scenario
are
included
in
Table
9.

2.2.4
Occupational
Post
Application
Risk
Characterization
The
actual
use
rates
of
dicamba
are
typically
less
than
the
maximum
label
rates
because
dicamba
is
usually
mixed
with
other
herbicides.
In
addition,
the
rate
of
2.8
lbs
ae/
acre
for
sugarcane
is
present
only
one
label
(
7969­
140).
The
rate
for
the
remaining
labels
is
2.0
lb
ae/
acre.
Page
21
of
33
2.3
Residential
Handler
Exposures
and
Risks
According
to
the
EPA
Pesticide
Sales
and
Usage
Report
for
2000/
2001,
dicamba
is
ranked
number
seven
among
the
ten
most
commonly
used
conventional
pesticide
active
ingredients
in
the
home
and
garden
market
sector.
This
list
includes
2,4­
D
and
MCPP­
p
and
which
rank
1
and
5,
respectively.

The
residential
products
are
typically
formulated
as
dry
weed
and
feed
products
or
as
liquids
in
concentrates
or
ready
to
use
sprays.
Many
of
these
formulations
include
other
herbicides
such
as
2,4­
D
and
MCPP­
p.
Spot
and
broadcast
treatments
are
both
included
on
the
labels.
Exposures
are
expected
to
be
short
term
in
duration
for
broadcast
treatments
because
the
label
allows
only
two
broadcast
treatments
per
year.
Exposures
are
also
expected
to
be
short
term
in
duration
for
spot
treatments
because
the
labels
recommend
repeat
applications
in
two
to
three
weeks
for
hard
to
kill
weeds.

2.3.1
Residential
Handler
Scenarios,
Data
Sources
and
Assumptions
Scenarios
The
following
scenarios
were
assessed.

1.
Hand
Application
of
Granules
2.
Belly
Grinder
Application
3.
Load/
Apply
Granules
with
a
Broadcast
Spreader
4.
Mix/
Load/
Apply
with
a
Hose­
end
Sprayer
(
Mix
your
own)
5.
Mix/
Load/
Apply
with
a
Hose­
end
Sprayer
(
Ready
to
Use)
6.
Mix/
Load/
Apply
with
Hand
Held
Pump
Sprayer
7.
Mix/
Load/
Apply
with
Ready
to
Use
Sprayer
Data
Sources
Exposure
data
for
scenarios
#
1
and
#
2
were
taken
from
PHED.
Exposure
data
for
scenarios
#
3,
#
4
and
#
5
were
taken
from
the
residential
portion
of
the
ORETF
Handler
Study
(
this
study
was
discussed
in
Section
2.1.2.)

Exposure
data
for
scenarios
#
6
and
#
7
were
taken
from
MRID
444598­
01,
which
has
recently
been
purchased
by
the
ORETF.
This
study
involved
low
pressure
handwand
and
RTU
trigger
sprayer
application
of
carbaryl
to
home
vegetable
plants.
Details
of
this
study
are
included
in
Appendix
D.

Assumptions
Regarding
Residential
Applicators
C
Clothing
would
consist
of
a
short­
sleeved
shirt,
short
pants
and
no
gloves.

C
Broadcast
spreaders
and
hose
end
sprayers
would
be
used
for
broadcast
treatments
and
the
other
application
methods
would
be
used
for
spot
treatments
only.

C
An
area
of
0.023
acre
(
1000
square
feet)
would
be
treated
per
application
during
spot
treatments
and
an
area
of
0.5
acre
would
be
treated
during
broadcast
applications.
Page
22
of
33
C
The
application
rate
is
1.0
lb
ae/
acre
as
listed
in
the
Dicamba
Use
Closure
Memo.

2.3.2
Residential
Handler
Exposure
and
Risk
Estimates
The
MOE
calculations
are
included
in
Appendix
D
and
a
summary
is
included
in
Table
11.
The
MOEs
exceed
the
target
MOE
of
100
and
the
risks
are
not
of
concern.

Table
11
­
Dicamba
Short
Term
MOEs
for
Homeowner
Applications
to
Lawns
(
Application
Rate
=
1.0
lb
ae/
acre)

Scenario
Treated
Area
(
acres/
day)
Combined
Dose
(
mg/
kg/
day)
Combined
MOEA
1
Hand
Application
of
Granules
(
spot
treatment)
0.023
0.0058
7800
2
Belly
Grinder
Application
(
spot
treatment)
0.023
0.0054
8300
3.
Load/
Apply
Granules
with
a
Broadcast
Spreader
0.5
0.00073
62000
4.
Mix/
Load/
Apply
with
a
Hose­
end
Sprayer
(
Mix
your
own)
0.5
0.012
3800
5.
Mix/
Load/
Apply
with
a
Hose­
end
Sprayer
(
Ready
to
Use)
0.5
0.0029
16000
6.
Mix/
Load/
Apply
with
Hand
Held
Pump
Sprayer
0.023
0.0019
24000
7.
Mix/
Load/
Apply
with
Ready
to
Use
Sprayer
0.023
0.0027
17000
A.
The
target
MOE
is
100.

2.3.3
Residental
Handler
Risk
Characterization
The
residential
handler
risks
were
calculated
using
standard
assumptions,
the
highest
quality
unit
exposure
data
available
and
the
maximum
label
application
rates.

2.4
Residential
Turf
Post
Application
Exposure
and
Risks
2.4.1
Residential
Turf
Post
Application
Exposure
Scenarios,
Data
Sources
and
Assumptions
Scenarios
The
following
exposure
scenarios
are
assessed
for
residential
post
application
risks
Acute
and
Short
Term
Exposures
of
Toddlers
Playing
on
Treated
Turf
Acute
and
Short
Term
Exposures
of
Adults
Performing
Yardwork
on
Treated
Turf
Acute
and
Short
Term
Exposures
of
Adults
Playing
Golf
on
Treated
Turf
Acute
Exposures
of
Toddlers
From
Incidental
Oral
Ingestion
of
Granules
Page
23
of
33
Data
Sources:

There
are
three
turf
transferable
residue
studies
(
MRID
446557­
02,
450331­
01
and
446557­
03
that
were
submitted
by
the
Broadleaf
Turf
Herbicide
TFR
Task
Force.
The
field
portion
of
the
studies
were
conducted
by
Grayson
Research
LLC
of
Creedmoor,
North
Carolina,
AGSTAT
of
Verona,
Wisconsin,
and
Research
for
Hire
of
Porterville,
California.
The
laboratory
analysis
for
all
three
studies
was
conducted
by
Covance
Laboratories
of
Madison,
Wisconsin.
These
studies
measured
the
dissipation
of
several
phenoxy
herbicides,
including
dicamba,
using
the
ORETF
roller
technique
(
also
called
the
modified
California
Roller).

The
was
an
additional
study
(
MRID
449590­
01)
that
was
submitted
by
Novartis
Crop
Protection.
This
field
portion
of
this
study
was
conducted
by
Research
Options,
Inc
of
Winter
Garden,
Florida,
ABC
Laboratories
California
of
Madera,
California
and
Crop
Management
Strategies
of
Germansville,
PA.
The
laboratory
analysis
for
all
three
sites
was
conducted
by
ABC
Laboratories
of
Columbia,
Missouri.
This
study
also
used
the
ORETF
roller
technique.

All
of
the
studies
were
reviewed
by
HED
and
were
found
to
meet
most
of
the
series
875
guidelines
for
postapplication
exposure
monitoring.
The
studies
are
summarized
on
the
following
pages
and
the
data
analyses
are
presented
in
Appendix
E.
The
abbreviations
DAT
and
HAT
refer
to
Day
After
Treatment
and
Hour
After
Treatment,
respectively.

Determination
of
Transferable
Turf
Residues
on
Turf
Treated
with
2,4­
D,
2,4­
DP­
p,
MCPP­
p
and
Dicamba,
MRID
446557­
02
(
Phase
1
­
Effect
of
Form)

The
purpose
of
this
study
was
to
assess
the
effects
of
different
forms
upon
the
day
zero
turf
transferable
residues
(
TTR)
and
dissipation
rates
of
phenoxy
herbicides
including
dicamba.
Dicamba
was
applied
with
2,4­
D
DMA
and
MCPP­
p
DMA
to
turf
plots
in
North
Carolina
using
a
groundboom
sprayer.
The
plots
were
mowed
to
a
height
of
two
inches
prior
to
the
application
and
were
not
mowed
again
until
after
the
seventh
day
of
sampling.
No
irrigation
was
performed.
Significant
rainfall
(
i.
e.
greater
than
0.05
inches)
did
not
occur
until
DAT
10
when
0.17
inches
occurred
prior
to
the
DAT
10
sample.

Sampling
was
conducted
with
a
ORETF
roller
using
a
27"
X
39"
percale
cotton
cloth
in
accordance
with
the
SOP
developed
by
the
ORETF.
Samples
were
collected
after
the
sprays
had
dried
and
at
0.5,
1,
2,
3,
4,
5,
6,
7,
10
and
14
DAT.
The
samples
were
analyzed
using
a
validated
method
that
had
an
LOQ
of
0.879
ng/
cm2.
The
concurrent
laboratory
recoveries
were
close
to
100
percent
and
were
acceptable.
The
average
field
recoveries
were
acceptable
with
a
range
of
68.9
to
87.1
percent
depending
upon
the
date
of
fortification
and
fortification
level.
The
TTRs
values
were
corrected
using
a
field
recovery
factor
of
0.689.

The
results
of
the
Phase
1
samples
are
shown
in
Table
12.
The
highest
TTR
levels
occurred
on
DAT
0.5.
The
TTR
levels
declined
to
the
LOQ
by
DAT
2.
Page
24
of
33
Table
12
­
Dissipation
of
Dicamba
Applied
to
Turf
Using
Various
Forms
(
Phase
1)

Dicamba
Form
Application
Rate
(
lb
ae/
acre)
Maximum
TTR2
(
ug/
cm2)
Percent
Applied
as
TTR
Correlation
Coefficient
Half
Life
(
days)

Dicamba
Mixture
0.20
0.055
+
0.012
(
n=
3)
2.5
0.89
(
n=
12)
0.38
1.
The
DMA
mixture
contained
Dicamba
with
2,4­
D
DMA
and
MCPP­
p
DMA
Determination
of
Transferable
Turf
Residues
on
Turf
Treated
with
2,4­
D
DMA
+
MCPP­
p
DMA
+
Dicamba
DMA
in
Various
Spray
Volumes,
­
MRID
446557­
03
(
Phase
2
­
Effect
of
Spray
Volume)

The
purpose
of
this
study
was
to
assess
the
effects
of
different
spray
volumes
upon
the
day
zero
TTRs
and
dissipation
rates
of
phenoxy
herbicides.
In
all
cases,
dicamba
was
applied
in
combination
with
MCPP­
p
DMA
and
2,4­
D
DMA
All
of
the
applications
were
made
to
cool
season
fescue/
blue
grass
turf
plots
in
North
Carolina
using
a
groundboom
sprayer.
The
plots
were
mowed
to
a
height
of
two
inches
prior
to
the
application
and
were
not
mowed
again
until
after
the
seventh
day
of
sampling.
No
irrigation
was
performed.
No
rain
occurred
on
DAT
0
or
DAT
1
and
0.17
inches
of
rain
occurred
prior
to
the
DAT
2
sample,
0.46
inches
occurred
prior
to
the
DAT
3
sample
and
0.03
inches
occurred
prior
to
the
DAT
4
and
5
samples.

Sampling
was
conducted
in
the
same
manner
as
for
Phase
1
using
an
ORETF
roller.
Samples
were
collected
at
3
and12
hours
after
treatment
(
HAT)
and
at
1,
2,
3,
4,
5,
6,
7,
10
and
14
DAT.
The
samples
were
analyzed
using
Method
2
as
described
and
validated
in
MRID
446557­
04
and
the
LOQ
was
0.879
ng/
cm2.
The
concurrent
laboratory
recovery
was
86.3
+
11.6
(
n=
26)
and
did
not
vary
significantly
with
respect
to
the
fortification
levels
which
ranged
from
1
to
400X
LOQ.
Field
recovery
samples
were
prepared
at
DAT
0
and
DAT
6
using
fortification
levels
of
0.004
and
0.04
ug/
cm2.
The
average
recoveries
for
each
subset
of
field
spikes
(
n=
6)
ranged
from
76.4
to
80.2
percent
depending
upon
the
fortification
level
and
date
of
preparation.
The
raw
data
were
corrected
for
field
recovery
by
using
0.78
which
is
overall
average
(
n=
12).

A
summary
of
the
results
are
shown
in
Table
13
and
a
more
detailed
listing
is
included
in
Appendix
E.
The
half
lives
ranged
from
0.33
to
0.39
days
and
were
calculated
based
upon
the
first
two
days
of
dissipation
because
the
TTRs
reached
the
LOQ
by
DAT
2.

Table
13
­
Dissipation
of
Dicamba
Applied
to
Turf
at
Various
Spray
Volumes
(
Phase
2)

Spray
Volume
(
GA/
acre)
Application
Rate
(
lb
ae/
acre)
Maximum
TTR1
(
ug/
cm2)
Percent
Applied
as
TTR
Correlation
Coefficient
Half
Life
(
days)

2
5
20
0.2
0.2
0.2
0.035
+
0.0072
(
n=
3)
0.036
+
0.0085
(
n=
3)
0.028
+
0.0060
(
n=
3)
1.4
1.5
1.1
0.80
(
n=
12)
0.97
(
n=
12)
0.95
(
n=
12)
0.39
0.33
0.35
1.
The
maximum
average
TTR
occurred
on
DAT
1.0,
DAT
0.0
and
DAT
0.5
for
the
2,
5
and
20
GPA
applications,
respectively.
Page
25
of
33
Determination
of
Transferable
Turf
Residues
on
Turf
Treated
with
2,4­
D
DMA
+
MCPP­
p
DMA
+
Dicamba
DMA
MRID
450331­
01
(
Two
Additional
Sites)

The
purpose
of
this
study
was
to
assess
the
effects
of
two
additional
sites
upon
the
day
zero
TTRs
and
dissipation
rates
of
phenoxy
herbicides.
Dicamba
was
applied
in
combination
with
MCPP­
p
DMA
and
2,4­
DP­
p
DMA
(
Treatment
4).
The
applications
were
made
to
turf
plots
in
Wisconsin
and
California
using
groundboom
sprayers
with
a
spray
volume
of
9.4
to
9.9
gallons
per
acre.
The
plots
were
mowed
to
a
height
of
two
inches
prior
to
the
application
and
were
not
mowed
again
until
after
the
seventh
day
of
sampling.
No
irrigation
was
performed.
No
rain
occurred
at
the
California
site,
however,
the
grass
was
wet
with
dew
during
the
DAT
0.5
sampling
which
occurred
at
night.
The
following
rainfall
occurred
at
the
Wisconsin
site:
0.025
inches
prior
to
the
HAT
8
sample,
0.145
inches
prior
to
the
HAT
12
sample
and
0.19
inches
prior
to
the
HAT
24
sample.

Sampling
was
conducted
in
the
same
manner
as
for
Phase
1
using
the
ORETF
roller.
Samples
were
collected
at
1,
4,
8,
12
and
24
HAT
and
2,
3,
4
and
7
DAT.
The
samples
were
analyzed
using
a
validated
method
and
the
LOQ
was
0.879
ng/
cm2.
The
concurrent
laboratory
recoveries
were
acceptable
for
both
sites.
Field
recovery
samples
were
prepared
in
the
same
manner
as
for
Phase
1
with
the
exception
that
a
different
fortification
solution
was
used.
In
Phase
1,
the
fortification
solution
contained
only
acetone
as
the
solvent,
while
in
this
study
0.1
M
phosphoric
acid
was
added
to
the
acetone.
The
recoveries
obtained
were
very
low
and
were
not
reported.
These
low
recoveries
were
thought
to
be
the
result
of
interference
caused
by
the
acid
interaction
with
the
cotton
during
storage
The
recoveries
from
phase
1
were
instead
used
as
a
surrogate.

The
results
of
this
study
are
shown
in
Table
14.
The
TTR
values
declined
to
the
LOQ
by
DAT
1
in
Wisconsin
and
to
2X
LOQ
by
DAT
7
in
California.
The
data
for
DAT
0.5
at
the
California
site
are
not
included
because
these
samples
were
collected
at
night
when
there
was
dew.

Table
14
­
Dissipation
of
Dicamba
Applied
to
Turf
at
Sites
in
California
and
Wisconsin
Site
­
Treatment1
Application
Rate
(
lb
ae/
acre)
Maximum
TTR2
(
ug/
cm2)
Percent
Applied
as
TTR
Correlation
Coefficient
Half
Life
(
days)

CA­
4
WI­
4
0.21
0.21
0.030
+
0.0040
(
n=
3)
0.034
+
0.0040
(
n=
3)
1.3
1.5
0.91(
n=
24)
0.90(
n=
15)
1.8
0.17
1.
Treatment
4
consisted
of
Dicamba
DMA
formulated
with
MCPP­
p
DMA
and
2,4­
D
DMA
2.
The
maximum
TTR
occurred
on
HAT
1
for
the
CA
site
and
at
HAT
8
for
the
WI­
5
site.
Page
26
of
33
Determination
of
Transferable
Turf
Residues
on
Turf
Treated
with
Dicamba
(
Vanquish)
­
MRID
449590­
01
In
this
study,
a
soluble
concentrate
formulation
of
dicamba
(
Vanquish)
was
applied
by
itself.
to
turf
plots
in
Florida
(
FL),
California
(
CA)
and
Pennsylvania
(
PA)
at
an
application
rate
of
1.0
lb
ae/
acre
with
a
spray
volume
of
50
gallons
per
acre.
The
applications
were
made
using
CO
2
powered
backpack
sprayers
in
FL
and
PA
and
a
groundboom
sprayer
in
CA.
The
turf
was
mowed
to
a
height
of
one
inch
two
days
prior
to
application
at
the
FL
site,
three
inches
seven
days
prior
to
application
at
the
CA
site
and
2
inches
one
day
prior
to
application
at
the
PA
site.
The
turf
was
not
mowed
during
the
study.
One
of
the
two
PA
sites
was
irrigated
with
0.28
inches
of
water
approximately
30
minutes
after
application
and
the
FL
and
CA
site
were
not
irrigated.
Significant
rainfall
(
0.71"
inches
on
day
2)
occurred
only
at
the
FL
site.
No
rain
occurred
at
the
CA
site,
and
only
a
small
amount
of
rain
(
0.06
inches
on
day
3)
occurred
at
the
PA
site.

Sampling
was
conducted
using
the
ORETF
roller
with
cotton
cloth
with
an
exposed
surface
area
of
5600
cm2.
Samples
were
collected
at
0,
4,
8,
24,
32­
36,
48,
56­
60
HAT
and
3,
5
and
7
DAT.
Four
samples
were
collected
at
each
plot
at
each
sampling
intervals.
The
samples
were
analyzed
using
a
validated
method
and
the
LOQ
was
0.000879
ug/
cm2.
The
concurrent
laboratory
recoveries
were
acceptable.
Field
recovery
samples
were
prepared
by
spiking
blank
sampling
cloths
with
25
or
2000
ug
of
dicamba
to
yield
fortification
levels
of
0.0045
or
0.36
ug/
cm2.
The
average
(
n=
6)
field
recoveries
were
87.1
percent
for
the
FL
site,
79.5
percent
for
the
CA
site
and
86.6
percent
for
the
PA
site.
The
recoveries
did
not
vary
significantly
between
fortification
levels.

The
raw
results
were
corrected
for
site
specific
field
recovery
and
are
shown
in
Table
15.
The
maximum
TTRs
at
the
non­
irrigated
plots
occurred
on
HAT
8
at
the
FL
site,
on
HAT
1
at
the
CA
site
and
on
HAT
3
at
the
PA
site.
The
TTRs
declined
to
the
LOQ
by
DAT
3
in
FL,
3X
LOQ
by
DAT
7
in
CA
and
6X
LOQ
by
DAT
7
in
PA.
Most
of
the
TTRs
at
the
irrigated
plot
were
close
to
the
LOQ.
Only
one
of
the
four
DAT
0
replicates
had
detectable
residues,
which
when
combined
with
the
other
three
replicates
that
were
at
the
LOQ,
yielded
the
maximum
TTR
of
0.0026
ug/
cm2.

Table
15
­
Dissipation
of
Dicamba
Applied
as
Vanquish
Site
Application
Rate
(
lb
ae/
acre)
Maximum
TTR
(
ug/
cm2)
Percent
Applied
as
TTR
Correlation
Coefficient
Half
Life
(
days)

FL
CA
PA
­
Dry
PA
­
Irrigated
1.0
1.0
1.0
1.0
0.29
+
0.072
(
n=
4)
0.17
+
0.017
(
n=
4)
0.13
+
0.0075(
n=
4)
0.0026
+
0.0042
(
n=
4)
2.6
1.5
1.2
0.023
0.85
(
n=
32)
0.97
(
n=
40)
0.90
(
n=
40)
N/
A
0.44
1.1
1.5
N/
A
Page
27
of
33
Application
of
the
TTR
Data
A
summary
of
the
data
used
for
exposure
assessment
is
included
in
Table
16.
A
maximum
TTR
value
of
2.6
percent
of
the
application
rate
was
derived
from
the
Vanquish
Study
(
MRID
449590­
01)
and
was
used
for
assessing
acute
exposures.
A
7
day
average
TTR
of
0.55
percent
of
the
application
rate
was
derived
from
the
California
site
of
MRID
450331­
01
which
had
a
half
life
of
1.8
days.

Table
16
­
Summary
of
TTR
Data
Used
for
Post
Application
Exposure
Assessment
MRID
449590­
01
450331­
01
Location
Florida
California
Precipitation
No
Rain
No
Rain
Application
Rate
(
lb
ae/
acre)
1.0
0.21
Maximum
TTR
(
ug/
cm2)
Maximum
TTR
(
percent
of
application
rate)
0.29
2.6
­
Note
1
0.033
1.3
Day
0
Average
TTR
(
ug/
cm2)
Day
0
Average
TTR
(
percent
of
application
rate)
0.10
0.90
0.033
1.3
­
Note
2
Semi­
log
Slope
Factor
N/
A
­
0.38
­
Note
2
7
day
Average
TTR
(
ug/
cm2)
7
day
Average
TTR
(
percent
of
application
rate)
N/
A
N/
A
0.013
0.55
­
Note
2
Note
1
­
This
value
was
used
to
derive
the
TTR
for
1day
acute
exposures.
Note
2
­
These
values
were
used
to
derived
the
TTR
for
seven
day
average
short
term
exposures.

General
Assumptions
The
following
general
assumptions
are
taken
from
the
Standard
Operating
Procedure
(
SOPs)
of
December
18,
1997
and
ExpoSAC
Policy
#
12
"
Recommended
Revisions
to
the
Standard
Operating
Procedures
for
Residential
Exposure
Assessments
of
February
22,
2001.

C
The
TTR
values
were
used
for
calculating
dermal
exposures
on
turf
because
they
were
greater
than
1.0%
of
the
application
rate.
These
values
were
adjusted
for
application
rates
as
needed.

C
An
assumed
initial
TTR
value
of
5.0%
of
the
application
rate
is
used
for
assessing
hand
to
mouth
exposures.

C
An
assumed
initial
TTR
value
of
20%
of
the
application
is
used
for
assessing
object
to
mouth
exposures.

C
Soil
residues
are
contained
in
the
top
centimeter
and
soil
density
is
0.67
mL/
gram.

C
Three
year
old
toddlers
are
expected
to
weigh
15
kg.

C
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.
Page
28
of
33
C
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.

C
Adults
are
assessed
using
a
transfer
coefficient
of
14,500
cm2/
hour.

C
Toddlers
are
assessed
using
a
transfer
coefficient
of
5200
cm2/
hour.

C
Golfers
are
assessed
using
a
transfer
coefficient
of
500
cm2/
hour.

C
An
exposure
duration
of
2
hours
per
day
is
assumed
for
toddlers
playing
on
turf
or
adults
performing
heavy
yardwork.

C
An
exposure
duration
of
4
hours
is
assumed
for
playing
golf.

Assumptions
Specific
to
Dicamba
The
following
assumptions
that
are
specific
to
dicamba
are
used
for
assessing
residential
post
application
exposures.

C
The
application
rate
of
1.0
lbs
ae/
acre
as
stated
in
the
Use
Closure
Memo
was
used.

Calculation
Methods
The
above
factors
were
used
in
the
standard
SOP
formulas
to
calculate
the
exposures.
These
formulas
are
described
in
Appendix
A.
MOEs
were
calculated
for
acute
dermal
and
incidental
oral
exposures
using
the
maximum
TTR
value
along
with
the
acute
dietary
NOAEL
of
300
mg/
kg/
day.
MOEs
for
short
term
exposures
were
calculated
using
the
seven
day
average
TTR
value,
because
the
short
term
dermal
NOAEL
of
45
mg/
kg/
day
was
based
upon
decreased
pup
body
weight
gain
which
did
not
occur
until
after
several
days
of
exposure.

2.4.2
Residential
Turf
Post
Application
Exposure
and
Risk
Estimates
The
MOEs
for
acute
exposures
are
summarized
in
Table
17
and
the
detailed
calculations
are
included
in
Appendix
F.
All
of
the
acute
MOEs
for
both
adult
and
toddler
exposures
exceed
the
target
MOE
of
300.
This
means
that
the
risks
for
adults
and
toddler
exposures
are
not
of
concern.

Table
17
­
Acute
Dicamba
MOEs
for
Turf
Exposures
(
Application
Rate
=
1.0
lb
ae/
acre)

Population/
Scenario
TTR
(
ug/
cm2)
TC
(
cm2/
hr)
Dermal
DoseB
Hand­
to
Mouth
Dose
Object
to
Mouth
Dose
Soil
Ingestion
Dose
Total
Dose
Total
MOEC
Toddlers/
Playing
0.29A
5,200
0.0030
0.015
0.0037
0.000050
0.049
6,100
Adults/
Yardwork
Adults/
Golfing
0.29A
14,500
500
0.018
0.0012
N/
A
N/
A
N/
A
0.018
17,000
240,000
A.
This
value
was
derived
from
the
maximum
TTR
of
2.6
percent
from
MRID
449590­
01.
B.
All
doses
are
expressed
in
mg/
kg/
day.
C.
Total
MOE
=
NOAEL/
Total
Dose
where
the
NOAEL
is
300
mg/
kg/
day.

The
target
MOE
for
adult
and
toddler
exposures
is
300.
Page
29
of
33
The
MOEs
for
short
term
exposures
are
summarized
in
Table
18.
All
of
the
short
term
MOEs
for
both
adult
and
toddler
exposures
exceed
the
target
MOE
of
100.

Table
18
­
Short
Term
Dicamba
MOEs
for
Turf
Exposures
(
Application
Rate
=
1.0
lb
ae/
acre)

Population/
Scenario
TTR
(
ug/
cm2)
TC
(
cm2/
hr)
Dermal
DoseB
Hand­
to
Mouth
Dose
Object
to
Mouth
Dose
Soil
Ingestion
Dose
Total
Dose
Total
MOEC
Toddlers/
Playing
0.060A
5,200
0.0062
0.0063
0.0016
0.000021
0.014
3,200
Adults/
Yardwork
Adults/
Golfing
0.060A
14,500
500
0.0037
0.0003
N/
A
N/
A
N/
A
0.0037
0.0003
12,000
170,000
A.
Seven
day
average
TTR
derived
from
the
California
TTR
Study
MRID
450331­
01.
B.
All
doses
are
expressed
in
mg/
kg/
day.
C.
Total
MOE
=
NOAEL/
Total
Dose
where
the
NOAEL
is
45
mg/
kg/
day.

The
target
MOE
for
adult
and
toddler
exposures
is
100.

2.4.3
Residential
Turf
Post
Application
Risk
Characterization
The
calculation
of
acute
MOEs
using
a
maximum
TTR
value
for
toddler
turf
post
application
exposure
represents
a
policy
change,
because
the
maximum
TTR
values
were
previously
only
used
to
calculate
short
term
MOEs.
The
dicamba
risk
assessment
team
decided
that
the
previous
approach
would
greatly
overestimate
the
short
term
risks,
because
the
short
term
incidental
oral
and
dermal
endpoints
were
based
upon
effects
that
would
only
occur
after
several
days
of
exposure.
The
team
also
decided
that
the
single
day
exposures
as
represented
by
the
maximum
TTR
values
would
be
more
appropriately
assessed
using
the
acute
dietary
endpoint.
The
short
term
exposures
were
assessed
using
the
seven
day
average
TTR
values
because
the
endpoint
occurred
after
several
days
of
exposure
and
because
the
TTR
data
were
collected
during
a
seven
day
time
period.

The
actual
use
rates
of
dicamba
are
typically
less
than
the
maximum
label
rates
because
dicamba
is
usually
mixed
with
other
herbicides
such
as
2,4­
D
and
MCPP­
p.
As
shown
in
Table
19,
the
application
rate
of
dicamba
ranges
from
0.03
to
0.20
lb
ae/
acre
when
dicamba
is
formulated
with
other
herbicides.
Page
30
of
33
Table
19
­
Dicamba
Application
Rates
in
Phenoxy
Herbicide
Liquid
Products
Product
Reg
#
Individual
Application
Rate(
lb
ae/
acre)

2,4­
D
MCPP­
p
Dicamba
2,4­
DP
Trimec
937
PBI
Gordon
Trimec
Plus
2217­
758
2217­
709
0.80
0.80
­­­­
0.40
0.20
0.20
0.40
­­­

Riverdale
Triplet
Sensitive
228­
288
0.41
0.72
0.18
­­­

Ortho
Weed
b
Gon
Trimec
Bentgrass
Formula
2217­
570
2217­
529
0.37
0.40
1.27
0.64
0.16
0.16
­­­
­­­

NuFarm
Tri­
Power
228­
262
1.36
0.26
0.13
­­­

PBI
Gordon
Trimec
849
2217­
597
0.57
1.06
0.12
­­­

Riverdale
Triplet
Selective
Herbicide
PBI
Gordon
Trimec
848
228­
264
2217­
531
1.19
0.99
0.32
0.48
0.11
0.11
­­­
­­­

Millenium
Ultra
TM
Plus
228­
382
0.83
­­­
0.10
­­­

PBI
Gordon
Trimec
Lawn
Weed
Killer
Lilly
Miller
Lawn
Weed
Killer
Bonide
Lawn
Weed
Killer
Dexol
Lawn
Weed
Killer
PBI
Gordon
Trimec
891
2217­
539
802­
485
4­
400
192­
118
2217­
517
0.73
0.77
0.73
0.73
0.95
0.18
0.19
0.35
0.35
0.25
0.08
0.08
0.08
0.08
0.08
­­­
­­­
­­­
­­­
­­­

PBI
Gordon
Speed
Zone
2217­
864
0.73
0.23
0.07
­­­

Trimec
932
2217­
749
1.49
0.29
0.06
­­­

EC
1382
Residential
2217­
855
0.35
0.14
0.03
­­­

2.5
Residential
Turf
Granule
Ingestion
Exposure
and
Risks
Scenarios
The
following
exposure
scenario
was
assessed
Acute
Exposures
of
Toddlers
from
Incidental
Oral
Ingestion
of
Granules
General
Assumptions
The
following
general
assumptions
are
taken
from
the
Standard
Operating
Procedure
(
SOPs)
of
December
18,
1997
and
ExpoSAC
Policy
#
12
"
Recommended
Revisions
to
the
Standard
Operating
Procedures
for
Residential
Exposure
Assessments
of
February
22,
2001.

C
The
assumed
ingestion
rate
is
0.3
gram/
day.
This
is
based
on
the
assumption
that
if
150
lbs
of
product
were
applied
to
a
½
acre
lawn,
the
amount
of
product
per
square
foot
would
be
3
g/
ft2
and
a
child
would
consume
one­
tenth
of
the
product
available
in
a
square
foot.

C
Three
year
old
toddlers
are
expected
to
weigh
15
kg.

C
The
application
rate
of
1.0
lbs
ae/
acre
as
stated
in
the
Use
Closure
Memo
was
used.
Page
31
of
33
C
The
percent
ai
in
granular
formulations
used
in
residential
settings
was
assumed
to
be
in
the
range
of
0.1
to
1.0
percent
based
upon
the
product
labels
listed
in
OPPIN.

Calculation
Methods
The
above
factors
were
used
to
calculate
the
potential
dose
rate
and
the
absorbed
dose
using
the
standard
SOP
formula
as
shown
in
Table
20
MOEs
were
then
calculated
using
the
acute
dietary
NOAEL
of
300
mg/
kg/
day
and
they
exceed
the
target
MOE
of
300.
This
means
that
the
risks
for
toddler
exposures
from
granular
ingestion
are
not
of
concern.

Table
20
­
Granule
Ingestion
Risks
for
Dicamba
Percent
ai
Potential
Dose
Rate1
(
mg/
day)
Absorbed
Dose2
(
mg/
kg/
day)
Acute
MOE3
0.1
0.3
0.02
15000
0.5
1.5
0.1
3000
1.0
3.0
0.2
1500
1.
Potential
Dose
Rate
(
PDR)
=
0.3
gram/
day
*
Percent
ai*
1000
mg/
gram
2.
Absorbed
Dose
=
PDR/
BW
3.
MOE
=
NOAEL/
Dose
where
the
NOAEL
=
300
mg/
kg/
day
Page
32
of
33
3.0
References
Dicamba
Smart
Meeting,
November
4,
2004,
BASF.

U.
S.
EPA,
February
10,
1998
Draft
Standard
Operating
Procedures
for
Residential
Exposure
Assessments.
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.

U.
S.
EPA,
1998.
PHED
Surrogate
Exposure
Guide,
V1.1.
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs,
August
1998.

U.
S.
EPA
SAP,
"
Exposure
Data
Requirement
for
Assessing
Risks
from
Pesticide
Exposure
of
Children",
SAP
Meeting
of
March
8,
1999,
page
60.

U.
S.
EPA,
1999,
"
Use
of
Values
from
the
PHED
Surrogate
Table
and
Chemical­
Specific
Data."
Science
Advisory
Council
for
Exposure,
Policy.
007,
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.

U.
S.
EPA,
August
7,
2000,
"
Agricultural
Default
Transfer
Coefficients"
Science
Advisory
Council
for
Exposure,
SOP
003.1,
.
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.

U.
S.
EPA,
July
5,
2000,
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture"
HED
Science
Advisory
Council
for
Exposure,
Policy.
009,
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.

U.
S.
EPA,
9/
14/
04,
Screening
Level
Estimates
of
Agricultural
Uses
of
Dicamba,
OPP
BEAD
Page
33
of
33
4.0
Glossary
of
Terms
Used
in
Occupational/
Residential
Exposure
Assessment
TERM
DEFINITION
AE
­
Acid
Equivalent
The
weight
of
dicamba
excluding
the
weight
of
the
ester
or
salt
groups.

Baseline
PPE
Includes
long
pants,
long
sleeved
shirt,
shoes,
socks
and
no
gloves
or
respirator
DAT
Day
after
treatment
Dose
The
amount
of
pesticide
that
is
absorbed
into
the
body.

Double
Layer
PPE
Includes
coveralls
over
single
layer
PPE
ExpoSac
­
Scientific
Advisory
Committee
for
Exposure
A
committee
within
the
EPA
Health
Effects
Division
that
reviews
pesticide
exposure
assessments
and
develops
policy.

Exposure
The
amount
of
pesticide
that
impinges
upon
the
skin
or
is
inhaled.

Handler/
Applicator
A
worker
who
mixes,
loads
and/
or
applies
pesticides
HAT
Hours
after
treatment
Intermediate
Term
31
days
to
six
months
MOE
­
Margin
of
Exposure
The
ratio
of
the
"
safe"
dose
(
usually
the
NOAEL)
divided
by
the
estimated
exposure.
Formerly
called
the
Margin
of
Safety.

NOAEL
No
Observed
Adverse
Effect
Level
ORETF
Outdoor
Residential
Exposure
Task
Force
PF5
Respirator
A
filtering
facepiece
respirator
(
i.
e.
dustmask)
that
has
a
protection
factor
of
5
when
properly
fitted.

PF10
Respirator
A
half
face
respirator
with
cartridges
that
has
a
protection
factor
of
10
when
properly
fitted.

PHED
Pesticide
Handlers
Exposure
Database
Re­
entry
Worker
One
who
works
in
fields
that
have
been
treated
with
pesticides
REI
­
Restricted
Entry
Interval
The
period
of
time
that
must
pass
following
pesticide
application
before
workers
are
re­
enter
the
treated
area.

ROW
­
Right
of
Way
Areas
such
as
roadsides,
powerlines,
railway
right­
of­
way
and
pipelines.

Short
Term
One
to
thirty
days
Single
Layer
PPE
Includes
baseline
PPE
with
chemical
resistant
gloves
Target
MOE
The
MOE
which
is
equal
to
the
uncertainty
factor
level
of
concern.
MOEs
that
are
less
than
the
target
MOE
indicate
risks
of
concern
that
may
require
additional
evaluation
and
refinement.