UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
OFFICE
OF
PREVENTION,
PESTICIDES,
AND
TOXIC
SUBSTANCES
WASHINGTON,
D.
C.
20460
May
27,
2004
MEMORANDUM
SUBJECT:
2,4­
D:
Revised
Occupational
and
Residential
Exposure
and
Risk
Assessment
and
Response
to
Phase
one
Comments
for
the
Registration
Eligibility
Decision
(
RED)
Document
[
PC
Code
030001,
DP
Barcode
D302261]

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

THROUGH:
Jeff
Dawson,
Chemist
And
Whang
Phang,
PhD,
Branch
Senior
Scientist
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

TO:
Bill
Hazel,
Risk
Assessor
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

Mark
Seaton,
Ph.
D.,
Chemical
Review
Manager
Reregistration
Branch
II
Special
Review
and
Reregistration
Division
(
SRRD),
7508C
The
following
is
in
reference
to
the
Occupational
and
Residential
(
ORE)
Aspects
of
the
"
Error
Only
Response
to
Health
Effects
Division's
Risk
Assessment
for
the
Reregistration
Eligibility
Decision
(
RED)
for
2,4­
Dichlorophenoxy
acetic
acid
(
2,4­
D)"
that
was
prepared
by
the
Industry
Task
Force
II
on
2,4­
D
Research
Data
on
April
21,
2004.
This
response
was
submitted
following
the
Phase
1
review
period.
The
ORE
Risk
Assessment
has
been
revised
as
appropriate
and
responses
to
the
Task
Force
comments
are
included
in
Appendix
J.
Page
Executive
Summary
i
1.0
Background
Information
1
1.1
Purpose
and
Criteria
for
Conducting
Exposure
Assessments
1.2
Toxicological
Endpoints
1.3
Incident
Reports
1.4
Summary
of
Use
Patterns,
Formulations
and
Application
Methods
2.0
Occupational
and
Residential
Exposures
and
Risks
11
2.1
Occupational
Handler/
Applicator
Exposures
&
Risks
11
2.1.1
Exposure
Scenarios
2.1.2
Exposure
Assumptions
and
Data
Sources
2.1.3
Exposure
and
Risk
Estimates
2.1.4
Risk
Characterization
2.2
Occupational
Post
Application
Exposures
&
Risks
19
2.2.1
Exposure
Scenarios
2.2.2
Exposure
Data
Sources,
Assumptions
and
Transfer
Coefficients
2.2.3
Exposure
and
Risk
Estimates
2.2.4
Risk
Characterization
2.3
Residential
Applicator
Exposure
and
Risks
28
2.3.1
Exposure
Scenarios,
Data
Sources
and
Assumptions
2.3.2
Exposure
and
Risk
Estimates
2.3.3
Risk
Characterization
2.4
Residential
Turf
Post
Application
Exposure
and
Risks
30
2.4.1
Exposure
Scenarios,
Data
Sources
and
Assumptions
2.4.2
Exposure
and
Risk
Estimates
2.4.3
Risk
Characterization
and
Comparison
to
Biomonitoring
Data
2.5
Recreational
Swimmer
Post
Application
Exposure
and
Risks
37
2.5.1
Exposure
Scenarios,
Data
Sources
and
Assumptions
2.5.2
Exposure
and
Risk
Estimates
2.5.3
Risk
Characterization
3.0
­
Data
Compensation
Issues
41
4.0
­
References
42
5.0
­
Glossary
of
Terms
44
Appendices
A
­
Standard
Formulas
Used
for
Calculating
2,4­
D
Occupational
and
Residential
Exposures
B
­
Occupational
Handler
Exposure
Data
and
Risk
Calculations
for
2,4­
D
C
­
Occupational
Post­
Application
Risks
of
2,4­
D
Short
Term
Exposures
D
­
Occupational
Post­
Application
Risks
of
2,4­
D
Intermediate
Term
Exposures
E
­
Residential
Handler
Exposure
Data
and
Risk
Calculations
for
2,4­
D
F
­
2,4­
D
Turf
Transferable
Residue
Data
G
­
Residential
Turf
Post
Application
Risk
Assessment
for
2,4­
D
H
­
2,4­
D
Swimmer
Exposures
I
­
2,4­
D
Aquatic
Dissipation
Data
J
­
Response
to
the
Phase
One
Comments
from
the
2,4­
D
Task
Force
i
Executive
Summary
2,4­
D
Product
Descriptions,
Uses
and
Application
Methods:

There
are
registered
products
of
2,4­
D
for
both
occupational
and
residential
site
applications.
The
registered
agricultural
uses
include
field/
row
crops,
orchard
floors,
vineyard
floors,
and
sod
farm
turf.
Residential
uses
include
broadcast
and
spot
treatment
on
turf.
The
acid,
dimethylamine
and
ethylhexyl
ester
forms
of
2,4­
D
account
for
the
most
products.
Most
of
the
2,4­
D
products
are
formulated
as
liquids
or
granules,
although
a
few
of
the
acid
and
salt
forms
are
also
formulated
as
water
soluble
powders.
The
residential
products
are
typically
formulated
as
dry
weed
and
feed
products
or
as
liquids
in
concentrates
or
ready
to
use
sprays.
The
2,4­
D
master
label
has
been
developed
by
the
2,4­
D
task
force
and
represents
the
maximum
application
rates
for
agricultural
and
non­
agricultural
uses.
Some
of
the
rates
are
lower
than
the
rates
present
on
existing
labels,
however,
the
agency
and
the
task
force
have
agreed
that
the
existing
labels
will
be
updated
with
the
new
rates
as
part
of
the
re­
registration
process.

Typically
one
to
three
applications
are
made
per
growing
season.
Applications
are
made
to
the
target
weeds
prior
to
crop
emergence,
after
crop
emergence,
prior
to
harvest
and
in
the
dormant
season,
depending
upon
the
crop.
The
2,4­
D
labels
allow
ground
and
aerial
application,
however,
they
do
not
allow
chemigation.
Ground
applications
are
made
whenever
possible
due
to
cost
and
convenience
while
aerial
applications
are
primarily
made
to
rice
fields
that
are
flooded
or
to
rangeland
areas
where
woody
weeds
are
too
tall
for
a
tractor
(
2,4­
D
Smart
Meeting,
2001).
Aquatic
areas
can
treated
from
boats
either
by
spraying
the
floating
weeds
or
by
applying
liquid
or
granular
materials
to
submerged
weeds.
Forestry
applications
can
be
made
by
rotary
winged
aircraft
(
i.
e.
helicopters)
for
large
scale
conifer
release
programs
or
by
backpack
for
smaller
areas
such
as
Christmas
tree
plantations.

Toxicology
Endpoints:

The
following
endpoints
as
selected
by
the
HIARC
(
US
EPA,
May
1,
2003)
were
used
for
assessing
2,4­
D
risks:


A
NOAEL
of
67
mg/
kg/
day
was
selected
from
an
acute
neurotoxicity
study
in
rats
during
which
in­
coordination
and
slight
gait
abnormalities
were
observed.
This
NOAEL
is
applicable
to
acute
incidental
oral
and
dermal
exposures.


A
NOAEL
of
25
mg/
kg/
day
was
selected
from
a
developmental
oral
study
in
rats
during
which
developmental
(
skeletal
variations)
and
maternal
(
decreased
body
weight
gain)
effects
were
observed.
This
NOAEL
is
applicable
to
short
term
incidental
oral,
dermal
and
inhalation
exposures.
ii

A
NOAEL
of
15
mg/
kg/
day
was
selected
from
a
sub­
chronic
oral
study
in
rats
during
which
decreased
body
weight/
body
weight
gain,
alterations
in
hematology
and
clinical
chemistry
parameters
and
cataract
formation
were
observed.
This
NOAEL
is
applicable
to
intermediate
term
incidental
oral,
dermal
and
inhalation
exposures.


A
dermal
absorption
factor
of
5.8
percent
was
selected
for
converting
dermal
exposures
to
oral
equivalent
doses.
An
inhalation
absorption
factor
of
100
percent
was
selected
for
converting
inhalation
exposures
to
oral
equivalent
doses.

Endpoints
were
also
selected
by
the
HIARC
for
chronic
exposures,
however,
these
endpoints
were
not
used
in
this
assessment
because
chronic
occupational
and
residential
exposures
to
2,4­
D
are
not
expected
to
occur.
2,4­
D
is
only
applied
a
couple
of
times
each
year
during
the
growing
season,
rapidly
dissipates
from
the
foliage
and
is
readily
excreted
from
the
human
body.

The
target
MOE
for
occupational
populations
is
100
which
includes
the
standard
uncertainty
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
residential
populations
is
1000
because
it
also
includes
a
database
uncertainty
factor
of
10X.
The
HIARC
determined
that
this
factor
is
needed
due
the
lack
of
certain
studies
since
the
available
data
provide
no
basis
to
support
reduction
or
removal
of
the
default
10X
factor.

Occupational
Handler/
Applicator
Exposure
and
Risk
Estimates:

The
non­
cancer
risks
(
i.
e.
MOEs)
for
occupational
exposures
were
calculated
for
short
and
intermediate
term
dermal
and
inhalation
exposures
using
standard
assumptions
and
unit
exposure
data
for
a
wide
range
of
application
methods
and
equipment.
The
standard
assumptions,
such
as
acres
treated
per
day,
were
taken
from
ExpoSAC
SOPs.
The
unit
exposure
data
were
taken
from
PHED,
the
ORETF
studies
for
professional
lawn
care
operators
and
a
California
DPR
study
for
backpack
applicators.
With
the
exception
of
mixing/
loading
wettable
powder,
most
of
the
MOEs
exceed
the
target
of
100
with
baseline
or
single
layer
PPE
and
are
not
of
concern.
This
level
of
PPE
is
generally
consistent
with
the
labels
which
typically
require
coveralls
and
gloves.
The
MOEs
for
handling
wettable
powder
are
acceptable
with
engineering
controls
(
i.
e.
water
soluble
bags).
Only
a
few
2,4­
D
products
are
formulated
as
wettable
powders
and
almost
all
of
these
products
are
packaged
in
water
soluble
bags.

Post­
Application
Occupational
Exposure
and
Risk
Estimates:

2,4­
D,
which
is
highly
selective
for
broadleaf
weeds,
can
cause
leaf
damage
to
some
of
the
labeled
broadleaf
crops
and
the
labels
specify
that
it
should
be
applied
to
the
ground
in
such
a
manner
as
to
minimize
crop
damage.
To
provide
weed
control
without
damaging
the
crops,
applications
are
made
in
the
dormant
season
or
prior
to
planting,
sprays
are
directed
to
the
row
middles
or
orchard
floors
and
drop
booms
and/
or
shields
are
used
to
prevent
crop
contact.
Broadcast
applications
can
be
made
to
grass
crops
such
cereal
grains,
rice
and
sugarcane
which
iii
are
tolerant
of
2,4­
D.
Given
the
above
characteristics
of
2,4­
D,
it
is
anticipated
that
post
application
exposures
would
primarily
occur
following
treatment
of
the
grass
crops.

MOEs
were
calculated
for
short
and
intermediate
term
post
application
exposures
using
standard
assumptions,
standard
transfer
coefficients
and
the
TTR
data.
All
of
the
MOEs
are
above
100
on
day
zero
which
indicates
that
the
risks
are
not
of
concern.
The
WPS
REI
ranges
from
12
to
48
hours
depending
upon
the
form
of
2,4­
D.

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.
Many
of
these
formulations
include
other
phenoxy
herbicides
such
as
MCPP­
p
and
MCPA.
Both
spot
and
broadcast
treatments
are
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
for
hard
to
kill
weeds
in
two
to
three
weeks.

The
MOEs
for
residential
handlers
exposures
were
calculated
using
standard
assumptions,
master
label
rates
and
PHED
and
ORETF
unit
exposure
data.
All
of
the
MOEs
exceed
the
target
MOE
of
1000
and
are
not
of
concern.

Data
Used
for
Turf
Post
Application
Exposure
Assessment
There
are
three
turf
transferable
residue
studies
that
were
submitted
by
the
Broadleaf
Turf
Herbicide
TTR
Task
Force.
These
studies
measured
the
dissipation
of
several
phenoxy
herbicides,
including
2,4­
D,
using
the
ORETF
roller
technique
(
which
is
also
called
the
modified
California
Roller).
The
studies
have
been
reviewed
by
HED
and
were
found
to
meet
all
of
the
series
875
guidelines
for
postapplication
exposure
monitoring.

The
purpose
of
the
first
study
was
to
assess
the
effects
of
the
different
chemical
forms
upon
the
day
zero
turf
transferable
residues
(
TTR)
and
dissipation
rates
of
phenoxy
herbicides
including
2,4­
D.
This
study
indicated
that
the
DMA
form
of
2,4­
D
had
the
highest
transferability
of
2.9
percent.
The
half
lives
ranged
from
0.53
days
to
1.2
days
and
no
rain
occurred.

The
purpose
of
the
second
study
was
to
assess
the
effects
of
different
spray
volumes
upon
the
day
zero
TTRs
and
dissipation
rates
of
phenoxy
herbicides.
The
day
zero
TTRs
ranged
from
0.87
to
1.3
percent
and
were
generally
greater
than
the
DAY
1
TTRs.
The
half
lives
were
fairly
consistent
and
were
short
(
0.30
days)
because
rain
occurred
on
Day
2
and
3.

The
purpose
of
third
study
was
to
assess
the
effects
of
two
additional
sites
(
California
and
Wisconsin)
upon
the
day
zero
TTRs
and
dissipation
rates.
The
TTRs
declined
to
the
LOQ
by
iv
DAT
1
in
Wisconsin
due
to
rain.
The
TTRs
remained
above
the
LOQ
at
the
California
site
because
no
rain
occurred
and
the
halflife
was
2.7
days.

Residential
Turf
Post
Application
Exposure
and
Risk
Estimates
The
MOEs
for
residential
turf
exposures
were
calculated
using
the
TTR
data,
master
label
rates
and
the
Residential
SOPs.
MOEs
were
calculated
for
acute
exposures
using
the
maximum
TTR
value
of
2.9
percent
of
the
application
rate
along
with
the
acute
NOAEL.
MOEs
for
toddler
short
term
exposures
were
calculated
using
the
seven
day
average
TTR
values
because
the
short
term
NOAEL
was
based
upon
decreased
body
weight
gain
which
occurred
after
several
days
of
exposure.
MOEs
for
adult
short
term
exposures
were
calculated
using
the
maximum
TTR
value
because
the
short
term
NOAEL
is
based
upon
developmental
effects
that
could
have
occurred
following
one
day
of
exposure.
All
of
the
MOEs
meet
or
exceed
the
target
MOE
of
1000.

The
results
of
a
biomonitoring
study
(
Harris
and
Solomon
1992)
were
also
used
to
calculate
dermal
MOEs
for
post
application
exposure
on
turf.
The
study
was
conducted
with
adult
volunteers
who
were
exposed
to
2,4­
D
while
performing
controlled
activities
for
one
hour
on
turf
treated
with
2,4­
D.
The
controlled
activities
were
conducted
at
1
hour
after
treatment
(
HAT)
and
at
24
HAT.
Ten
volunteers
participated
in
the
study.
Five
volunteers
wore
long
pants,
a
tee
shirt,
socks
and
closed
footwear.
The
other
five
wore
shorts
and
a
tee
shirt
and
were
barefoot.
The
volunteers
walked
on
the
turf
for
a
period
of
5
minutes
and
then
sat
or
lay
on
the
area
for
5
minutes
and
then
continued
in
this
fashion
for
50
more
minutes.
Each
volunteer
collected
all
urine
for
the
next
96
hours
immediately
following
the
exposure.
The
MOEs
for
the
DAT
1
volunteers
who
wore
shorts
and
no
shoes
ranged
from
1000
to
26000
with
the
lowest
MOE
corresponding
to
the
volunteer
who
removed
his
shirt
during
the
exposure
period.
The
MOEs
for
the
remaining
volunteers
ranged
from
17000
to
27000.

Recreational
Swimmer
Post
Application
Exposure
and
Risk
Estimates
The
master
label
indicates
that
2,4­
D
can
be
used
for
aquatic
weed
control
of
surface
weeds
such
as
Water
Hyacinth
and
submersed
weeds
such
as
Eurasian
Milfoil.
Surface
weeds
are
controlled
by
foliar
applications
at
a
maximum
rate
of
2.0
lbs
ae/
acre.
Submersed
weeds
are
controlled
by
the
subsurface
injection
of
liquids
or
the
application
of
slow
dissolving
granules.
Although
many
herbicide
treatments
are
applied
to
aquatic
areas
where
recreational
swimming
is
not
likely
to
occur,
some
of
the
subsurface
treatments
are
made
at
recreational
lakes
because
the
Eurasian
Milfoil
interferes
with
swimming,
fishing
and
boating.

The
MOEs
for
recreational
swimmers
were
calculated
using
master
label
target
water
concentrations,
standard
exposure
factors
and
the
dermal
and
ingestion
exposure
formulae
from
the
SWIMODEL.
MOEs
were
calculated
for
acute
exposures
using
the
maximum
target
concentration
value
along
with
the
appropriate
acute
NOAELs.
MOEs
for
toddler
short
term
exposures
were
calculated
using
the
seven
day
average
water
concentration
because
the
short
v
term
NOAEL
was
based
upon
decreased
body
weight
gain
which
occurred
after
several
days
of
exposure.
MOEs
for
adult
short
term
exposures
were
calculated
using
the
maximum
water
concentrations
value
because
the
short
term
NOAEL
is
based
upon
developmental
effects
that
could
have
occurred
following
one
day
of
exposure.

All
of
the
dermal
MOEs
meet
or
exceed
the
target
MOE
of
1000
when
the
2,4­
D
acid
or
2,4­
D
DMA
are
used
because
these
forms
have
very
low
skin
permeability
coefficients.
The
dermal
MOEs
are
of
concern
when
2,4­
D
BEE
is
used
because
2,4­
D
BEE
has
a
relatively
high
skin
permeability
coefficient.
The
ingestion
MOEs
are
of
concern
for
short
term
children's
exposure
and
is
not
dependent
on
the
form
used.
If
a
lower
target
concentration
of
2
ppm
is
used,
the
MOEs
for
ingestion
rise
to
above
1000,
however,
the
dermal
MOEs
remain
below
1000
for
2,4­
D
BEE
exposures.

Incident
Reports
The
incident
report
was
prepared
by
the
HED
Chemistry
and
Exposure
Branch
(
US
EPA,
2004).
A
total
of
45
incidents
were
reported
in
the
OPP
Incident
Data
System
and
many
of
these
incidents
involved
irritant
effects
to
the
eyes,
skin
and
occasionally
respiratory
passages.
Poison
Control
Center
Incident
Data
(
1993
to1998)
indicated
that
2,4­
D
is
generally
less
likely
than
other
pesticides
to
cause
minor,
moderate
or
life
threatening
symptoms.
The
most
common
symptoms
were
dermal
irritation
and
ocular
problems.
Incident
data
from
CA
DPR
indicated
that
the
number
of
cases
generally
ranges
from
0
to
3
per
year
and
most
of
these
cases
were
due
to
eye
or
skin
effects.
Incident
data
from
the
National
Pesticide
Information
center
for
the
years
1996
to
2002
indicated
that
an
average
of
3
cases
definitely
or
probably
related
to
2,4­
D
exposure
were
reported
per
year.

Risk
Characterization
The
occupational
handler
risks
are
mainly
of
concern
when
handling
2,4­
D
as
a
wettable
powder
without
engineering
controls
(
i.
e.
the
powder
is
not
in
water
soluble
bags).
Only
a
few
2,4­
D
products
are
formulated
as
wettable
powders
and
most
of
these
products
are
packaged
in
water
soluble
bags.

The
occupational
post
application
MOEs
are
above
the
target
MOE
of
100
on
day
zero
and
many
are
greater
than
1000
which
means
that
the
risks
are
generally
low.

The
master
label
application
rate
of
2.0
lb
ae/
acre
was
used
for
the
residential
handler
and
post
application
turf
assessments.
Many
of
the
labels
have
application
rates
in
the
range
of
0.5
to
1.5
lb
ae/
acre
because
2,4­
D
is
formulated
with
other
phenoxy
herbicides
such
as
MCPP­
p
and
MCPA.
vi
The
probability
that
a
person
would
swim
in
an
area
recently
treated
for
milfoil
is
low
because
the
presence
of
milfoil
makes
swimming
difficult
and
unpleasant.
The
dermal
exposures
from
2,4­
D
BEE
might
be
less
than
calculated
because
2,4­
D
BEE
degrades
rapidly
to
form
2,4­
D
acid.
According
to
EFED,
the
average
half
life
of
BEE
is
2.6
hours
based
upon
several
literature
studies
that
cover
a
wide
range
of
field
conditions.

The
acute
MOEs
may
underestimate
risk
in
cases
where
swimming
occurs
immediately
after
application
before
mixing
has
occurred.
Field
dissipation
studies
reviewed
by
EFED
indicated
that
2,4­
D
concentrations
sometimes
exceeded
the
target
concentration
in
parts
of
the
treated
area
shortly
after
application.
The
short
term
MOEs
from
water
ingestion
are
an
upper
bound
estimate
of
risk
because
dissipation
was
not
taken
into
account.
Field
dissipation
studies
indicated
that
the
2,4­
D
half
lives
following
the
subsurface
injection
of
2,4­
D
to
lakes
and
ponds
ranged
from
2.9
to
29.5
days
with
an
average
of
11.4
days
and
a
geometric
mean
of
7.3
days.
1
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
(
i.
e.,
mixers,
loaders,
applicators,
etc.)
during
use
or
to
persons
entering
treated
areas
after
application
is
completed.
2,4­
D
(
2,4­
dichlorophenoxy
acetic
acid;
CAS
#
94­
75­
7)
meets
both
criteria.
There
is
potential
exposure
to
private
growers
and
custom
applicators
from
agricultural
site
applications
of
2,4­
D.
In
addition,
the
general
public
may
be
exposed
to
2,4­
D
during
or
after
application
to
residential
lawns.

2,4­
D
is
produced
in
various
forms
including
acid,
sodium
salt,
amine
salts
and
esters.
A
listing
of
these
forms
is
included
in
Table
1.

Table
1
­
2,4­
D
Forms
2,4­
D
Form
PC
CODE
2,4­
D
Acid
2,4­
D
Sodium
Salt
2,4­
D
diethanolamine
salt
(
DEA)
2,4­
D
dimethylamine
salt
(
DMA)
2,4­
D
isopropylamine
salt
(
IPA)
2,4­
D
trisisopropanolamine
(
TIPA)
2,4­
D
2­
butoxyethyl
ester
(
BEE)
2,4­
D
2­
ethylhexyl
ester
(
2­
EHE)
2,4­
D
isopropyl
ester
(
IPE)
030001
030004
030016
030019
030025
030035
030053
030063
030066
Many
of
the
2,4­
D
products
also
contain
other
phenoxy
herbicides
such
as
MCPA
and
MCPP­
p.
These
herbicides
are
not
addressed
in
this
risk
assessment.

1.2
Acute
Toxicity
and
Endpoints
Used
for
Risk
Assessment
Acute
Toxicity
The
results
of
acute
toxicity
testing
are
summarized
in
Table
2.
The
sodium
salt,
IPE,
BEE
and
EHE
forms
of
2,4­
D
are
mild
to
moderate
eye
irritants
(
i.
e.
Toxicity
Category
III)
while
all
of
the
other
forms
are
severe
eye
irritants
(
i.
e.
Toxicity
Category
I).
All
of
the
forms
are
of
moderate
toxicity
(
Tox
III)
via
oral
and
dermal
exposure.
With
the
exception
of
the
BEE
ester,
all
of
the
forms
are
of
low
toxicity
(
Tox
IV)
for
primary
skin
irritation.
None
of
the
forms
are
dermal
sensitizers.
2
Table
2
­
Acute
Toxicity
Categories
for
the
Various
Forms
of
2,4­
D
2
,4­
D
Form
Guideline
(
Number)
Acid
Sodium
Salt
DEA
DMA
IPA
IPE
TIPA
BEE
2­
EHE
Acute
Oral
(
870.1100)
III
III
III
III
III
III
III
III
III
Acute
Dermal
(
870.1200)
III
III
III
III
III
III
III
III
III
Acute
Inhalation
(
870.1300)
III
No
Data
IV
IV
IV
IV
IV
IV
IV
Primary
Eye
Irritation
(
870.2400)
I
III
I
I
I
III
I
III
III
Primary
Skin
Irritation
(
870.2500)
IV
IV
IV
IV
IV
IV
IV
III
IV
Dermal
Sensitization
(
870.2600)
Not
a
dermal
sensitizer
­
all
forms
Note:
The
acute
toxicity
categories
range
from
I
which
is
the
most
toxic
to
IV
which
is
the
least
toxic.

Toxicological
Endpoints
Used
for
ORE
Risk
Assessment
The
toxicological
endpoints
that
were
used
to
complete
occupational
and
residential
exposure
assessments
are
summarized
in
Table
3.
These
endpoints
were
selected
from
animal
studies
by
the
HIARC
and
are
discussed
in
detail
in
HED
Document
#
0051866
of
May
1,
2003.

The
combined
uncertainty
factor
which
defines
the
target
MOE
for
occupational
populations
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
residential
populations
is
1000
because
it
also
includes
a
database
uncertainty
factor
of
10X.
The
HIARC
determined
that
this
factor
is
needed
due
the
lack
of
certain
studies
since
the
available
data
provide
no
basis
to
support
reduction
or
removal
of
the
default
10X
factor.
These
studies
include
a
developmental
neurotoxicity
study
and
a
repeat
of
2­
generation
reproduction
study
using
the
new
protocol.
3
Table
3
­
2,4­
D
Toxicology
Endpoints
Used
for
ORE
Assessment
EXPOSURE
SCENARIO
DOSE
(
mg/
kg/
day)
ENDPOINT
(
NOAEL/
LOAEL
=
mg/
kg/
day)
TARGE
T
MOE
STUDY
Acute
Dietary
(
Females
13­
50
years
of
age)
NOAEL=
25
Developmental
toxicity
Skeletal
malformations
and
variations
with
a
LOAEL
of
75.
100
=
O
1000
=
R
Developmental
rat
study
Acute
Dietary
General
Population
NOAEL
=
67
Gait
abnormalities
with
a
LOAEL
of
227.
The
NOAEL
for
systemic
toxicity
was
227[
the
highest
dose
tested].
1000
=
R
Acute
Nuerotoxicity
in
rats
Short
Term
Dermal,
Inhalation
and
Incidental
Oral
NOAEL=
25
Maternal
and
Developmental
toxicity
Developmental
­
skeletal
malformations
and
variations
with
a
LOAEL
of
75.
Maternal
­
Decreased
weight
gain
with
a
LOAEL
of
75.
100
=
O
1000
=
R
Developmental
rat
study
Intermediate
Term
Dermal,
Inhalation
and
Incidental
Oral
NOAEL
=
15
Decreased
body
weight/
body­
weight
gain,
alterations
in
some
hematology
[
decreased
platelets
]
and
clinical
chemistry
[
decreased
T3
and
T4]
parameters,
and
cataract
formation
with
a
LOAEL
of
100.
100
=
O
1000
=
R
Sub­
chronic
oral
study
in
rats
Long
Term
Dermal,
Inhalation
and
Incidental
Oral
NOAEL
=
5.0
Decreased
body
weight/
body­
weight
gain,
alterations
in
hematology,
clinical
chemistry
parameters,
increased
kidney
weights,
degeneration
of
the
descending
proximal
tubules,
hepatocellular
hypertrophy,
lung
inflammation
and
adipose
tissue
atrophy
with
a
LOAEL
of
75.
At
the
high­
dose
level,
there
also
were
microscopic
lesions
in
the
eyes,
liver,
testes,
thyroid,
and
lungs.
100
=
O
1000
=
R
Chronic
oral
toxicity
study
in
rats
Notes
1.
Oral
endpoint
were
used
for
dermal
exposure,
therefore
a
dermal
absorption
factor
of
5.8%
of
oral
exposure
was
used.
2.
Oral
endpoints
were
used
for
inhalation
exposure,
therefore
inhalation
exposure
was
assumed
to
be
equivalent
to
oral
exposure.
3.
The
target
MOE
is
100
for
occupational
populations
(
O)
and
1000
for
residential
populations
(
R).

Carcinogenicity
of
2,4­
D
The
HED
Carcinogenicity
Assessment
Review
Committee
(
CARC)
concluded
that
2,4­
D
"
should
remain
classified
as
a
group
D
­
Not
Classifiable
as
to
Human
Carcinogenicity.
That
is,
the
evidence
is
inadequate
and
cannot
be
interpreted
as
showing
either
the
presence
or
absence
of
a
carcinogenic
effect."
This
conclusion
is
discussed
in
the
EPA/
OPP
Memorandum
"
Carcinogenicity
Peer
Review
(
4th)
of
2,4­
Dichlorophenoxyacetic
acid",
TXR
#
005017
of
January
29,
1997.
This
memo
also
states
that
"
Overall,
the
pattern
of
responses
observed
in
both
in
vitro
and
in
vivo
tests
indicated
that
2,4­
D
was
not
mutagenic
(
although
some
cytogenic
effects
were
observed)".
4
1.3
Incident
Report
The
incident
report
was
prepared
by
the
HED
Chemistry
and
Exposure
Branch
(
US
EPA,
2004).
A
total
of
45
incidents
were
reported
in
the
OPP
Incident
Data
System.
Many
of
these
incidents
involved
irritant
effects
to
the
eyes,
skin
and
occasionally
respiratory
passages.
Poison
Control
Center
Incident
Data
(
1993
to1998)
indicated
that
2,4­
D
is
generally
less
likely
than
other
pesticides
to
cause
minor,
moderate
or
life
threatening
symptoms.
The
most
common
symptoms
were
dermal
irritation
and
ocular
problems.

There
were
33
cases
reported
in
the
California
Pesticide
Illness
Surveillance
Program
for
the
years
1982­
2001
where
2,4­
D
was
used
alone
or
was
judged
to
be
responsible
for
the
health
effects.
With
the
exception
of
1989
when
seven
cases
were
reported,
the
number
of
cases
per
year
ranged
from
0
to
3.
Of
the
33
cases,
13
were
due
to
systemic
effects,
18
were
due
to
eye
or
skin
effects,
1
was
due
to
respiratory
effects
and
1
was
due
a
combination
of
effects.
Seven
of
the
13
systemic
cases
occurred
in
1989.
Twenty
two
of
the
cases
involved
pesticide
handling
(
mixing,
loading,
application
or
storage),
seven
involved
drift,
one
case
involved
field
worker
exposure
and
3
cases
involved
unspecified
exposures.
Many
of
the
handler
cases
occurred
during
equipment
cleaning
or
repair
or
when
a
hose
broke.
Six
of
the
seven
drift
cases
involved
a
helicopter
application
that
violated
label
instructions.

According
to
the
National
Pesticide
Information
center,
2,4­
D
was
number
8
in
terms
of
calls
received
with
a
total
of
429
incidents
reported
in
humans
and
108
incidents
reported
in
animals
(
mostly
pets)
during
the
years
1984
to
1991.
A
similar
pattern
was
also
observed
during
the
years
1996
to
2002
when
a
total
of
368
incidents
were
reported
in
humans
and
206
incidents
were
reported
in
animals.
Of
the
incidents
reported
from
1996
to
2002,
19
incidents
in
humans
and
3
incidents
in
animals
were
considered
to
be
definite
or
probable.

The
incident
report
includes
a
review
of
the
incidents
reported
in
the
literature.
Many
of
these
incidents
were
the
result
of
accidental
or
intentional
ingestion
of
relatively
large
amounts
of
2,4­
D
and
some
resulted
in
death
due
to
renal
failure,
acidosis
and
electrolyte
imbalance.
Single
doses
of
5
mg/
kg/
day
have
been
administered
to
human
subjects
without
adverse
affects
and
one
subject
consumed
500
mg
per
day
for
3
week
without
experiencing
symptoms
or
signs
of
illness.
Neurotoxic
effects
such
as
peripheral
neuropathy
have
been
observed
following
dermal
exposures,
however,
it
is
not
certain
that
exposures
to
other
neurotoxicants,
such
as
solvents,
were
entirely
excluded.

The
incident
report
concludes
with
the
following
recommendations:
(
1)
Dermal
PPE
may
be
important
not
only
to
prevent
minor
dermal
irritant
effects,
but
also
long
term
effects
of
the
muscles.
Labels
should
clearly
warn
that
significant
amounts
of
2,4­
D
spilled
on
the
skin
should
be
rinsed
off
with
copious
amounts
of
soap
and
water
immediately
after
exposure.
(
2)
Eye
protection
for
both
occupational
and
residential
users
is
warranted
because
a
large
number
of
problems
have
occurred
among
workers
and
residential
users
who
got
2,4­
D
in
their
eyes.
5
1.4.
Summary
of
Use
Patterns,
Formulations
and
Application
Methods
Uses
The
2,4­
D
Task
Force
has
developed
a
Master
Label
for
Reregistration
of
2,4­
D
Uses
(
2,4­
D
Master
Label,
2003)
and
SRRD
has
determined
that
this
label
will
be
used
for
risk
assessment
(
EPA,
2003).
There
are
registered,
supported
products
of
2,4­
D
intended
for
both
occupational
and
residential
site
applications.
The
registered
agricultural
uses
include
field
/
row
crops,
orchard
floors,
vineyard
floors,
and
sod
farm
turf.
Residential
uses
include
broadcast
and
spot
treatment
on
turf.

Based
upon
available
pesticide
survey
usage
information
for
the
years
1992­
2000,
the
Biological
and
Economic
Effects
Division
(
BEAD)
of
EPA
estimates
that
total
annual
domestic
usage
for
agricultural
applications
of
2,4­
D
is
approximately
30
million
pounds
active
ingredient
(
ai).
Based
upon
information
for
the
years
1993­
1999,
BEAD
estimates
that
total
annual
domestic
usage
for
non­
agricultural
applications
of
2,4­
D
is
approximately
16
million
pounds
ai.
A
listing
of
the
use
sites
with
the
largest
amounts
of
2,4­
D
used
and/
or
the
highest
percent
crop
treated
is
given
in
Table
4.

Table
4
­
Qualitative
Usage
Analysis
Summary
for
2,4­
D
Use
Site
Amount
Used
(
pounds)
Percent
of
Total
Amount
Used
Percent
Crop
Treated
Pasture/
Rangeland
Spring
Wheat
Winter
Wheat
Field
Corn
Soybeans
Fallow,
Summer
Filberts
Sugar
cane
Barley
Total
Agriculture
11
million
3.8
million
3.3
million
2.9
million
1.7
million
1.4
million
26,000
335,000
1
million
30
million
37%
13%
11%
9.7%
5.7%
4.7%
0.087%
1.1%
3.3%
3%
51%
15%
9%
5%
7%
49%
36%
36%

Lawns
by
Homeowner
Lawns
by
PCO
Roadways/
Rights
of
Way
Total
Non­
Agriculture
8.3
million
3.2
million
1.4
million
16
million
52%
20%
7.0%

Source:
QUA
Report
for
2,4­
D,
EPA
BEAD,
8/
9/
01.
6
Mode
of
Action
and
Targets
Controlled
2,4­
D
is
a
highly
selective
herbicide
that
is
used
mainly
for
post
emergence
control
of
certain
broadleaf
weeds
and
woody
plants.
It
is
translocated
throughout
the
weed
plant
and
has
a
complex
mechanism
of
action
resembling
those
of
auxins
(
growth
hormones)
and
affects
cellular
division,
activates
phosphate
metabolism,
and
modifies
nucleic
acid
metabolism
(
Ware
2000).
It
is
well
tolerated
by
grass
crops
such
as
small
grains,
however,
it
can
be
highly
damaging
to
broadleaf
crops.

Formulation
Types
and
Percent
Active
Ingredient
According
to
EPA
OPP
REFS
label
tracking
system,
as
of
01/
29/
03
there
are
approximately
600
active
products
of
2,4­
D
formulated
from
9
different
forms.
A
listing
of
these
forms
is
included
in
Table
5.
The
acid,
DMA
and
2­
EHE
forms
of
2,4­
D
have
the
most
products.
Most
of
the
2,4­
D
products
are
formulated
as
liquids
or
granules,
although
a
few
of
the
acid
and
salt
forms
are
also
formulated
as
wettable
powders.
The
residential
products
are
typically
formulated
as
dry
weed
and
feed
products
or
as
liquids
in
concentrates
or
ready
to
use
sprays.

Table
5
­
2,4­
D
Forms
and
Number
of
Labels
2,4­
D
Form
PC
CODE
Number
of
Labels
Predominant
Formulations
Other
Formulations
Acid
030001
100
Liquids
and
granulars
Wettable
Powder
(
8
labels)

Sodium
Salt
030004
7
granular
Wettable
Powder
(
1
label)

DEA
030016
3
Liquids
None
DMA
030019
342
Liquids
and
granulars
Wettable
Powder
(
4
labels)

IPA
030025
8
Liquids
None
TIPA
030035
20
Liquids
and
granulars
None
BEE
030053
14
Liquids
and
granulars
None
2­
EHE
030063
111
Liquids
and
granulars
None
IPE
030066
5
Liquids
None
Application
Rates,
Timing
and
Frequency
of
Applications
The
2,4­
D
master
label
has
been
developed
by
the
2,4­
D
task
force
and
represents
the
maximum
application
rates
for
agricultural
and
non­
agricultural
uses.
Some
of
the
rates
are
lower
than
the
rates
present
on
existing
labels,
however,
the
agency
and
the
task
force
have
agreed
that
all
of
the
2,4­
D
the
labels
will
be
updated
with
the
new
rates
as
part
of
the
registration
process.
It
was
also
decided
that
all
of
the
registrants,
including
those
that
are
not
in
the
2,4­
D
7
task
force,
will
have
to
conform
to
the
master
label
rates.
The
master
label
agreement
is
discussed
in
a
memo
from
SRRD
to
EFED
and
HED
(
EPA,
March
18,
2003).

Typically
one
to
three
applications
are
made
per
growing
season.
Applications
are
made
to
the
target
weeds
prior
to
crop
emergence,
after
crop
emergence,
prior
to
harvest
and
in
the
dormant
season,
depending
upon
the
crop.
The
label
required
spray
volumes
for
ground
applications
range
from
20
gallons
for
most
crops
to
400
gallons
per
acre
for
brush
control.
2,4­
D
can
be
applied
over
the
top
to
tolerant
crops
such
as
small
grains
and
rice,
but
must
be
directed
or
shielded
for
the
more
sensitive
crops
such
as
fruits
and
berries.

The
application
rates
as
taken
from
the
master
label
are
included
in
Table
6
for
non­
crop
areas
and
Table
7
for
agricultural
crops.
The
average
application
rates
from
the
2,4­
D
QUA
report
(
EPA
BEAD
2001)
are
shown
for
comparison.
With
the
exception
of
filberts,
the
QUA
data
indicate
that
only
one
application
is
made
to
most
crops.
The
National
Agricultural
Pesticide
Impact
Assessment
Program
(
NAPIAP)
report
on
Phenoxy
Herbicides
indicates
that
one
2,4­
D
application
is
made
annually
to
turfgrass.

Table
6
­
2,4­
D
Application
Rates
for
Non­
Crop
Areas
Aquatic
Areas,
Forestry,
Non­
Crop
Areas
and
Turf
Acid
Equivalent
(
ae)
Application
Rates
Per
Application/
Per
crop
or
Year
Master
Label
Amount
Used
per
QUA
Report
Aquatic
Areas
­
Floating
Weeds
2.0/
4.0
per
acre
512,000
lbs1
Aquatic
Areas
­
Submerged
Weeds
10.8
per
acre
foot
Tree
and
Brush
Control
­
Tree
Injection
1
to
2
ml
per
inch
of
trunk
diameter
136,000
lbs
Forestry
­
Weed
and
Brush
Control
4.0/
4.0
per
acre
Forestry
­
Conifer
Release
4.0/
4.0
per
acre
Irrigation
Ditch
Banks
2.0/
4.0
per
acre
Rights
of
Way
Areas
2.0/
4.0
per
acre
2.1
million
lbs
Rangeland,
Pastures
2.0/
4.0
per
acre
Turf
­
Grass
Grown
for
Seed
or
Sod
2.0/
4.0
per
acre
351,000
lbs
Turf
­
Ornamental
2.0/
4.0
per
acre
11.6
million
lbs
1.
According
to
the
NAPIAP
report
97789
acres
were
treated
for
floating
weeds
and
4652
acres
were
treated
for
submerged
weeds
by
state
agencies
in
1993.
8
Table
7
­
2,4­
D
Application
Rates
for
Agricultural
Crops
Agricultural
Crops
Acid
Equivalent
(
ae)
Application
Rates
per
Acre
Per
Application/
Per
crop
or
Year
Master
Label
Average
Rate
per
QUA
Report
Asparagus
2.0/
4.0
1.1/
1.3
Blueberries
­
Low
Bush
Wiper
Bar
0.0375
lb/
GA
0.46/
0.51
Blueberries
­
High
Bush
1.4
Citrus
(
Growth
Regulator)
0.1
No
Data
Conifer
Plantations
4.0
No
Data
Corn
(
sweet)
Corn
(
field
and
pop)
0.5
to
1.0/
1.5
0.5
to
1.5/
3.0
0.48/
0.51
0.44/
0.46
Cranberries
­
granular
applications
Cranberries
­
liquid
applications
4.0
1.2
1.8/
2.0
Fallowland
and
Crop
Stubble
2.0/
NS
0.69/
0.89
Filberts
1.0
lb
per
100
Ga/
4
Apps
per
year
0.64/
1.7
Grain
Sorgum
0.5
to
1.0/
NS
0.46/
0.50
Grapes
1.36
0.73/
0.87
Orchard
Floors
(
Pome
and
Stone
Fruits,
Tree
Nuts)
2.0/
4.0
Apples
=
1.2/
1.4
Pears
=
1.1/
1.5
Potatoes
0.07/
0.14
0.10/
0.17
Rice
1.0
or
1.5/
1.5
0.92/
0.94
Soybeans
(
Preplant
burndown)
0.5
or
1.0/
1.0
0.46/
0.47
Strawberries
(
Except
CA
or
FL)
1.5
1.2/
1.3
Sugarcane
2.0/
4.0
0.75/
0.99
Cereal
Grains
(
Wheat,
Barley,
Millet,
Oats
and
Rye)
0.5
or
1.25/
1.75
Wheat=
0.44/
0.48
Barley
=
0.46/
0.47
Oats
=
0.46/
0.46
Rye
=
0.50/
0.50
Millet=
0.44/
0.44
Wild
Rice
(
MN
only)
0.25/
0.25
0.20/
0.20
9
Other
Sources
of
Use
Information
The
Phenoxy
Herbicide
NAPIAP
report
(
Burnside
et.
al.
1996)
has
a
great
deal
of
information
regarding
the
use
of
2,4­
D
on
a
wide
variety
of
crops.
Selected
information
that
is
relevant
for
2,4­
D
occupational
exposure
assessment
is
summarized
in
Table
8.

The
USDA
Forest
Service
2,4­
D
Risk
Assessment
(
USFS,
1998)
has
useful
information
about
2,4­
D
applications
in
forests
and
rights
of
way
areas.
This
information
is
summarized
below:


The
most
commonly
used
ground
application
method
is
backpack
(
selective)
foliar
applications
and
a
worker
can
treat
approximately
0.5
acre
per
hour.


Hack
and
squirt
applications
are
used
to
eliminate
large
trees
during
site
preparation,
conifer
release
or
rights
of
way
maintenance.
The
worker
usually
treats
0.5
acres
per
hour.


Boom
spray
or
roadside
hydraulic
spraying
is
used
primarily
for
roadside
rights
of
way
management.
Usually
8
acres
are
treated
in
a
45
minute
period
with
200
gallons
of
spray
solution,
however,
some
special
truck
mounted
spray
systems
may
be
used
to
treat
12
acres
in
a
35
minute
period
with
300
gallons.


Aerial
application
is
currently
not
used
by
the
Forest
Service.


The
typical
application
rate
is
1.0
lb
ae/
acre
with
a
range
of
0.5
to
2.0
lbs
ae/
acre.
10
Table
8
­
2,4­
D
Use
Information
in
the
Phenoxy
Herbicide
NAPIAP
Report
Use
Site
NIPIAP
Findings
Aquatic
Weed
Control
2,4­
D
accounted
for
56%
of
aquatic
acreage
treated.
97789
acres
were
treated
for
water
hyacinth
and
4652
acres
were
treated
for
Eurasian
water
milfoil
by
state
agencies
in
1993.
2,4­
D
provides
control
for
at
least
one
season.
Liquid
formulations
are
primarily
used
for
hyacinth
while
granular
formulations
are
primarily
used
for
milfoil.
State
agencies
want
to
use
liquid
formulations
for
milfoil
because
this
would
significantly
reduce
costs.

Asparagus
Used
on
27%
of
the
crop.
Only
use
amine.
Broadcast
applied
before
spears
emerge
in
the
spring
or
between
cuttings.
Directed
spray
is
applied
after
harvest
with
drop
nozzles
to
keep
2,4­
D
off
of
ferns.

Citrus
IPE
form
is
applied
as
a
growth
regulator
to
delay
harvest.

Conifer
Release
Most
herbicides
are
applied
by
helicopter
in
western
regions.
In
the
south,
skidder
mounted
broadcast
systems
with
boomless
nozzles
are
also
in
extensive
use.
The
typical
application
rate
is
2.0
lbs
ae
per
acre.

Conifer
Plantations
Many
growers
selective
spray
with
2,4­
D
in
backpack
sprayers
in
June.

Corn
(
field)
Preharvest
applications
are
not
commonly
made
because
the
weeds
are
too
large,
yield
reduction
has
already
occurred,
crop
is
too
tall
for
ground
application
and
drift
may
occur
from
aerial
application.

Corn
(
sweet)
Similar
to
field
corn
though
sweet
corn
is
more
sensitive
and
drop
nozzles
are
used.
Normally
only
one
application
is
made
per
season.

Fallow
land
Approximately
20%
of
the
72
million
acres
in
fallow
was
treated
once
with
2,4­
D
at
a
rate
of
0.5
lb
ae/
acre.
70%
of
fallow
acreage
in
Kansas
was
treated
with
2,4­
D.

Grain
Sorgum
Major
use
is
post
emergence
control
of
broadleaf
weeds.

Grapes
2,4­
D
is
important
for
the
control
of
annual
broadleaf
weeds.

Orchard
Floors
Used
for
selective
control
of
broadleaf
weeds
in
a
grass
cover.

Rice
(
except
CA)
18.5%
of
crop
treated
nationally
with
45%
crop
treated
in
Louisiana.
One
treatment
per
year.

Rights
of
Way
Most
products
are
applied
by
truck
mounted
sprayers
and
spray
trains.
Treatments
are
applied
by
backpack
for
ornamental
plantings
and
around
facilities
such
as
pump
stations.
Generally
applied
in
the
spring
but
also
applied
in
the
fall
in
the
south.
Rates
range
from
1
to
2
lb/
A.

Soybeans
Is
used
to
control
existing
vegetation
prior
to
planting
no­
till
soybeans.

Strawberries
In
the
northeastern
states
where
straw
berries
are
a
perennial
crop,
70­
90%
of
the
acreage
is
treated
with
2,4­
D
after
harvest.
Use
is
insignificant
in
CA
because
of
methyl
bromide
fumigation.

Sugarcane
In
some
states
multiple
applications
are
made.

Small
Grains
Use
of
2,4­
D
is
greater
on
spring
wheat
than
on
winter
wheat
because
winter
wheat
is
higher
yielding
and
more
competitive
against
weeds.

Wild
Rice
(
MN
only)
About
10%
of
crop
is
treated
at
a
rate
of
0.25
lb
ae/
acre.
11
12
Application
Methods
The
2,4­
D
labels
allow
ground
and
aerial
application,
however,
they
do
not
allow
chemigation.
Ground
applications
are
made
whenever
possible
due
to
cost
and
convenience
while
aerial
applications
are
made
primarily
to
rice
fields
that
are
flooded
or
rangeland
areas
where
woody
weeds
are
too
tall
for
a
tractor
(
2,4­
D
Smart
Meeting,
2001).
Wiper
bar
applications
can
be
made
to
crops
such
as
blueberries
and
cranberries.
Aquatic
weeds
can
treated
from
boats
either
by
foliar
applications
to
floating
weeds
or
by
subsurface
application
of
liquids
or
granular
materials
to
submersed
weeds.
Forestry
applications
can
be
made
by
rotary
winged
aircraft
(
i.
e.
helicopters)
for
large
scale
conifer
release
programs
or
by
backpack
for
smaller
areas
such
as
christmas
tree
plantations.
Forestry
applications
can
also
be
made
to
unwanted
trees
by
injection
or
frill
treatment.

2.0
Occupational
and
Residential
Exposures
and
Risks
As
discussed
above,
2,4­
D
is
used
both
in
the
agricultural
and
residential
environment.
The
risks
of
mixing,
loading
and
applying
2,4­
D
in
the
agricultural
environment
are
discussed
in
section
2.1.
Occupational
post
application
exposures
and
risks
are
discussed
in
section
2.2.
Residential
applicator
exposures
and
risk
are
discussed
in
section
2.3
and
residential
turf
post
application
exposures
and
risks
are
discussed
in
section
2.4.
Recreational
swimmer
post
application
exposure
and
risks
are
discussed
in
section
2.5.

2.1
Occupational
Handler/
Applicator
Exposures
&
Risks
2.1.1
Exposure
Scenarios
The
following
exposure
scenarios
were
assessed
based
upon
the
application
methods
listed
in
Table
9.

Mixer/
Loader
Mix/
Load
Wettable
Powder
Mix/
Load
Liquid
Formulations
Load
Granules
Applicator
Aerial
Application
Groundboom
Application
Subsurface
Application
of
Liquids
to
Submersed
Aquatic
Weeds
Airblast
Application
Backpack
Application
Rights
of
Way
(
ROW)
Application
Foliar
Application
of
Liquids
to
Floating
Aquatic
Weeds
Turfgun
Application
Broadcast
Spreader
Application
13
Mixer/
Loader/
Applicator
Mix/
Load/
Apply
Wettable
Powder
with
a
Turfgun
Mix/
Load/
Apply
Liquids
with
a
Turfgun
Mix/
Load/
Apply
Water
Dispersable
Granules
with
a
Turfgun
Mix/
Load/
Apply
Liquids
with
a
Backpack
Sprayer
Load/
Apply
Granules
with
a
Push
Spreader
Flagger
Flag
Aerial
Application
2.1.2
Exposure
Assumptions
and
Data
Sources
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.

$
A
listing
of
application
methods
and
amounts
of
acreage
treated
per
8
hour
day
is
included
in
Table
9.


The
application
rate
for
submerged
aquatic
weeds
is
based
upon
the
master
label
rate
of
10.8
lbs
a.
i.
per
acre
foot
times
an
average
lake
depth
of
5
feet.


Maximum
application
rates
and
daily
acreage
were
used
to
evaluate
short
term
exposures.


Average
application
rates
were
used
to
evaluate
intermediate
term
exposures.


A
body
weight
of
60
kg
was
assumed
for
short
term
exposures
because
the
short
term
endpoint
relates
to
females
13­
50
years
of
age.


A
body
weight
of
70
kg
was
assumed
for
intermediate
term
exposures
because
the
intermediate
term
endpoint
is
not
gender
specific.


The
dermal
absorption
rate
is
5.8%.


The
inhalation
absorption
rate
is
100%.


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


Single
Layer
PPE
includes
baseline
PPE
with
gloves.


Double
Layer
PPE
includes
coveralls
over
single
layer
PPE

Double
Layer
PPE
PF5
includes
above
with
a
PF5
respirator
(
i.
e.
a
dustmask)


Double
Layer
PPE
PF10
includes
above
with
a
PF10
cartridge
respirator

Only
closed
cockpit
airplanes
are
used
for
aerial
application.


There
are
very
little
exposure
data
to
evaluate
the
exposure
in
rotary
winged
aircraft,
therefore,
the
exposure
data
for
fixed
wing
aircraft
are
used
as
a
surrogate.


Airplane
and
helicopter
pilots
do
not
wear
chemical
resistant
gloves.
14
Table
9
­
2,4­
D
Application
Methods
Application
Method
Typical
Crops
Treated
Treated
Areaa
Aerial
Small
Grain,
Field
Corn,
Sugarcane
Citrus
Growth
Regulation
1200
350
Groundboom
Small
Grains,
Field
Corn,
Sugarcane
Orchard/
Vineyard
Floors
Strawberries
200
80
80
Subsurface
Application
of
Liquids
Submersed
Aquatic
Weeds
30b
Airblast
Citrus
Growth
Regulation
40
Backpack
Sprayer
­
Mix/
Load/
Apply
Christmas
Tree
Plantations
2c
Backpack
Sprayer
­
Apply
Only
Conifer
Release
4d
Right
of
Way
(
ROW)
Sprayer
Weed
Control
­
20
gallons
per
acre
Brush
Control
­
400
gallons
per
acre
50e
2.5e
Foliar
Application
of
Liquids
Floating
Aquatic
Weeds
10f
Broadcast
Spreader
­
Tractor
Drawn
or
Boat
Mounted
Turf
Submersed
Aquatic
Weeds
40
50g
Turfgun
Turf
5
Broadcast
Spreader
­
Push
Type
Turf
5
Notes
a.
Except
as
noted,
the
acres
treated
per
day
values
are
from
ExpoSAC
Policy
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture",
Revised
7/
5/
2000.

b.
The
area
treated
for
aquatic
application
of
liquids
to
submersed
aquatic
weeds
is
based
information
provided
in
an
email
of
12/
11/
03
from
Dr.
Kurt
Getsinger
of
the
US
Army
Corps
of
Engineers
to
Timothy
C.
Dole
of
the
US
EPA
Office
of
Pesticide
Programs.

c.
The
area
treated
for
Backpack
Sprayer
(
Mix/
Load/
Apply)
is
40
gallons
per
day
from
ExpoSAC
Policy
#
9
divided
by
the
label
recommended
spray
volume
of
20
gallons
per
acre.

d.
The
area
treated
for
Backpack
Sprayer
(
Apply
Only)
is
4
acres
per
day
based
upon
the
acreage
treated
in
CA
DPR
HS­
1769
normalized
to
an
8
hour
day.

e.
The
area
treated
for
ROW
sprayers
was
determined
by
the
dividing
the
daily
spray
volume
handled
(
1000
gallons
per
day)
from
ExpoSAC
Policy
#
9
by
the
label
recommended
spray
volume
of
20
gallons
per
acre
for
weed
control
and
400
gallons
per
acre
for
woody
brush
control.

f.
The
area
treated
for
foliar
application
of
liquids
to
floating
aquatic
weeds
is
based
upon
use
information
reported
in
the
HED
Memorandum
"
Occupational
and
Residential
Exposure
Characterization/
Risk
Assessment
for
Triclopyr
Triethylamine
for
Aquatic
Weed
Control,
DP
Barcode
D269448
of
7/
22/
2002.

g.
The
area
treated
for
application
of
granules
to
submersed
aquatic
weeds
is
based
upon
information
provided
in
an
email
of
11/
22/
2000
from
Jim
Kannenburg
of
Marine
Biochemists/
Applied
Biochemists
to
Troy
Swackhammer
of
the
US
EPA
Office
of
Pesticide
Programs.
15
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
forestry
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
B
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
B1
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.

ORETF
Data
16
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
conifer
release.
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
17
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
10.
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
10
­
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
Exposure
and
Risk
Estimates
Calculation
Methodology
and
Equations
Daily
dermal
and
inhalation
exposures,
absorbed
doses
and
MOEs
are
calculated
as
described
in
Appendix
A.
The
basic
rationale
for
these
calculations
is
that
the
daily
exposure
is
the
product
of
the
amount
of
ai
handled
per
day
times
a
unit
exposure
value.
The
target
MOEs
are
100
for
both
short
and
intermediate
term
exposures.
Scenarios
with
MOEs
greater
than
the
target
MOEs
are
not
of
concern
for
the
occupational
population.

Results
and
Comparison
to
Target
MOE
The
MOEs
for
Handlers
are
summarized
in
Tables
11
and
12
and
a
detailed
listing
of
these
MOEs
is
also
included
in
Appendix
B.
With
the
exception
of
mixing/
loading
wettable
powder,
most
of
the
MOEs
exceed
the
target
of
100
with
baseline
or
single
layer
PPE
and
are
not
of
concern.
The
MOEs
for
handling
wettable
powder
are
acceptable
with
engineering
controls
(
i.
e.
water
soluble
bags).
The
labels
typically
require
single
layer
PPE
for
applicators
and
handlers
and
that
a
probe
and
pump
mechanical
transfer
system
or
spigot
be
used
for
containers
of
5
gallons
or
more.
The
mechanical
transfer
system
or
spigot
is
not
required
for
1
to
5
gallon
containers,
however,
additional
PPE
(
coveralls
or
a
chemical
resistant
apron)
are
required
if
the
mechanical
system
or
spigot
are
not
used.
Most
of
the
wettable
powder
products
are
packaged
in
water
soluble
bags.
18
Table
11
­
Summary
of
2,4­
D
Short
Term
MOEs
for
Occupational
Handlers
Exposure
Scenario
Crop
Type
Application
Rate
(
lb
ae/
acre)
Acres/
Day
Baseline
Single
Layer
Single
Layer
PF5
Single
Layer
PF10
Double
Layer
PF10
Eng.
Control
Mixer/
Loader
(
M/
L)

M/
L
WP
All
Crops
0.25
to
4
5
to
1200
>
1.4
>
6
>
17
>
22
>
26
>
390
M/
L
Liquids
All
Crops
0.25
to
4
5
to
1200
>
1.8
>
130
>
200
>
220
>
270
>
550
M/
L
Liquids
Submersed
Weeds
54
30
5.5
370
580
630
820
1600
Load
Granulars
for
Broadcast
Spreader
Golf
Courses
and
Aquatic
Areas
2
to
54
40
or
50
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
Applicator
(
APP)

Aerial
Application
All
Crops
1.25
to
4.0
1200
ND
ND
ND
ND
ND
>
850
Groundboom
Application
All
Crops
1.25
to
4
40
to
200
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
Subsurface
Aquatic
Application
of
Liquids
Submersed
Weeds
54
30
600
600
970
1050
1300
2800
Airblast
Application
Citrus
0.1
40
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
Backpack
Application
Conifer
Release
4
4
ND
230
260
260
ND
ND
ROW
Application
Weed
Control
2
50
190
570
640
650
870
ND
Foliar
Aquatic
Application
of
Liquids
Floating
Weeds
2
10
950
>
1000
>
1000
>
1000
>
1000
>
1000
Turfgun
Application
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
>
1000
Broadcast
Spreader
Application
Golf
Courses
and
Aquatic
Areas
2
or
54
40
or
50
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
Mixer/
Loader/
Applicator
(
M/
L/
A)

M/
L/
A
Liquids
with
Backpack
Sprayer
Christmas
Trees
4
2
ND
>
1000
>
1000
>
1000
>
1000
ND
M/
L/
A
WD
Granules
with
a
Turfgun
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
ND
M/
L/
A
Wettable
Powder
with
a
Turf
Gun
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
>
1000
M/
L/
A
Liquid
Flowables
with
a
Turfgun
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
ND
Load/
Apply
Granules
with
a
Push
Spreader
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
ND
Flagger
Flag
Aerial
Liquid
Application
All
Crops
1.25
to
4.0
1200
>
320
>
300
>
410
>
430
>
470
>
16000
MOEs
in
bold
font
do
not
exceed
the
target
MOE
of
100
and
are
of
concern
19
Table
12
­
Summary
of
2,4­
D
Intermediate
Term
MOEs
for
Occupational
Handlers
Exposure
Scenario
Crop
Type
Application
Rate
(
lb
ae/
acre)
Acres/
Day
Baseline
Single
Layer
Single
Layer
PF5
Single
Layer
PF10
Double
Layer
PF10
Eng.
Control
Mixer/
Loader
(
M/
L)

M/
L
WP
All
Crops
0.25
to
4
5
to
1200
>
1.7
>
8.3
>
24
>
31
>
37
>
540
M/
L
Liquids
All
Crops
0.25
to
4
5
to
1200
>
2.6
>
170
>
280
>
300
>
390
>
750
M/
L
Liquids
Submersed
Weeds
54
30
3.8
250
420
450
570
1100
Load
Granulars
for
Broadcast
Spreader
Golf
Courses
or
Aquatic
Areas
2
or
54
40
or
50
>
180
>
190
>
530
>
680
>
1000
>
1000
Applicator
(
APP)

Aerial
Application
All
Crops
0.5
to
2.0
1200
ND
ND
ND
ND
ND
>
1200
Groundboom
Application
All
Crops
0.5
to
4
40
to
200
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
Subsurface
Aquatic
Application
Submersed
Weeds
54
30
420
420
680
730
920
2000
Airblast
Application
Citrus
0.1
40
>
1000
>
1000
>
1000
>
1000
>
1000
>
1000
Backpack
Application
Conifer
Release
2
4
ND
320
360
370
ND
ND
ROW
Application
Weed
Control
2
50
130
390
450
460
610
ND
Foliar
Aquatic
Application
of
Liquids
Floating
Weeds
and
Wild
Rice
4
or
0.25
10
>
330
>
990
>
1000
>
1000
>
1000
>
1000
Turfgun
Application
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
>
1000
Broadcast
Spreader
Application
Golf
Courses
and
Aquatic
Areas
2
or
54
40
or
50
>
220
>
240
>
590
>
720
>
1000
>
1000
Mixer/
Loader/
Applicator
(
M/
L/
A)

M/
L/
A
Liquids
with
Backpack
Sprayer
Conifer
Plantations
4
2
ND
720
860
880
1400
ND
M/
L/
A
WD
Granules
with
a
Turfgun
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
ND
M/
L/
A
Wettable
Powder
with
a
Turf
Gun
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
>
1000
M/
L/
A
Liquid
Flowables
with
a
Turfgun
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
ND
Load/
Apply
Granules
with
a
Push
Spreader
turf
2
5
ND
>
1000
>
1000
>
1000
>
1000
ND
Flagger
Flag
Aerial
Liquid
Application
All
Crops
0.50
to
2.0
1200
>
910
>
860
>
1200
>
1300
>
1400
>
32000
MOEs
in
bold
font
do
not
exceed
the
target
MOE
of
100
and
are
of
concern
20
2.1.4
Risk
Characterization
Only
a
few
2,4­
D
products
are
formulated
as
wettable
powders
and
most
of
these
products
are
packaged
in
water
soluble
bags.
These
products
are
labeled
primarily
for
use
on
turf.

2.2
Occupational
Post
Application
Exposure
and
Risks
Post
application
2,4­
D
exposures
can
occur
in
the
agricultural
environment
when
workers
enter
fields
recently
treated
with
2,4­
D
to
conduct
tasks
such
as
scouting
and
irrigation.

2.2.1
Post
Application
Exposure
Scenarios
2,4­
D,
which
is
highly
selective
for
broadleaf
weeds,
can
cause
leaf
damage
to
some
of
the
labeled
broadleaf
crops
and
the
labels
specify
that
it
should
be
applied
to
the
ground
in
such
a
manner
as
to
minimize
foliar
residues
and
crop
damage.
This
is
particularly
true
for
crops
such
as
berries,
grapes
and
tree
fruits.
To
provide
weed
control
without
damaging
the
crops,
applications
are
made
during
the
dormant
season
or
prior
to
planting,
sprays
are
directed
to
the
row
middles
or
orchard
floors
and
drop
booms
and/
or
shields
are
used
to
prevent
crop
foliar
contact.
These
techniques
also
prevent
post
application
exposures
because
they
minimize
the
amount
of
residue
on
the
crop
foliar
surfaces.
Broadcast
applications
can
be
made
to
grass
crops
such
cereal
grains,
rice
and
sugarcane
which
are
tolerant
of
2,4­
D.

Given
the
above
characteristics
of
2,4­
D,
it
is
anticipated
that
post
application
exposures
would
primarily
occur
following
treatment
of
the
grass
crops.
Because
2,4­
D
is
typically
applied
one
to
three
times
per
season
and
because
the
agricultural
scenarios
occur
for
only
a
few
months
per
year,
it
is
anticipated
that
2,4­
D
exposures
would
primarily
be
short
term
and
secondarily
intermediate
term.

Potential
inhalation
exposures
are
not
anticipated
for
the
post­
application
worker
scenarios
because
of
the
low
vapor
pressure
of
2,4­
D
(
2.0e­
07
torr
at
20o
C).

In
the
Worker
Protection
Standard
(
WPS)
a
restricted
entry
interval
(
REI)
is
defined
as
the
duration
of
time
which
must
elapse
before
residues
decline
to
a
level
so
entry
into
a
previously
treated
area
and
engaging
in
a
specific
task
or
activity
would
not
result
in
exposures
which
are
of
concern.
The
WPS
Restricted
Entry
Interval
(
REI)
for
2,4­
D
is
12
hours
for
the
ester
and
sodium
salt
forms
and
is
48
hours
for
the
acid
and
amine
salt
forms.
21
2.2.2
­
Exposure
Data
Sources,
Assumptions
and
Transfer
Coefficients
Data
Sources:

There
are
three
turf
transferable
residue
studies
that
were
submitted
by
the
Broadleaf
Turf
Herbicide
TTR
Task
Force.
The
field
portion
of
the
studies
were
conducted
by
Grayson
Research
LLC
of
Creedmore,
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
2,4­
D,
using
the
OREFT
roller
technique
(
which
is
also
called
the
modified
California
Roller).
The
studies
have
been
reviewed
by
HED
and
were
found
to
meet
all
of
the
series
875
guidelines
for
postapplication
exposure
monitoring.
The
studies
are
summarized
on
the
following
pages.

Determination
of
Transferable
Turf
Residues
on
Turf
Treated
with
2,4­
D,
2,4­
D­
p,
MCPA,
MCPP­
p
and
Dicamba,
MRID
446557­
01(
Phase
1
­
Effect
of
Form)

The
purpose
of
this
study
was
to
assess
the
effects
of
different
forms
of
phenoxy
herbicides
including
2,4­
D
upon
the
day
zero
turf
transferable
residues
(
TTR)
and
dissipation
rates.
In
two
cases
2,4­
D
was
applied
by
itself
while
in
one
case
it
was
applied
as
a
tank
mixture
with
the
other
herbicides.
All
of
the
applications
were
made
to
cool
season
fescue
turf
plots
in
North
Carolina
using
a
ground­
boom
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
days
after
treatment
(
DAT).
The
samples
were
analyzed
using
Method
1
as
described
and
validated
in
MRID
446557­
04
and
the
LOQ
was
0.879
ng/
cm2.
The
concurrent
laboratory
recoveries
were
108
+
11.3
(
n=
8)
for
2,4­
D
2­
EHE
and
108
+
15.4
(
n=
15)
for
2,4­
D
DMA.
These
recoveries
did
not
vary
significantly
with
respect
to
the
fortification
levels
which
ranged
from
1
to
900X
LOQ.
Field
recovery
samples
were
prepared
at
DAT
0
and
DAT
6
using
fortification
levels
of
0.004
and
0.04
ug/
cm2.
The
recoveries
for
2,4­
D
EHE
were
110
+
8.4
(
n=
12)
and
did
not
vary
with
respect
to
fortification
level
or
day
of
preparation.
The
recovery
for
2,4­
D
DMA
was
99.1
+
7.7
(
n=
6)
and
did
not
vary
with
respect
to
fortification
level.
Only
the
DAT
0
samples
were
used
for
2,4­
D
DMA,
however,
because
the
evaporation
of
the
extraction
solvent
caused
high
recoveries
on
the
DAT
6
samples.
The
raw
data
were
not
corrected
for
field
recovery
because
the
recoveries
were
greater
than
90
percent.

A
summary
of
the
results
are
shown
in
Table
13
and
a
more
detailed
listing
is
included
in
Appendix
F.
The
highest
TTR
levels
occurred
on
DAT
1
for
the
single
ingredient
application
and
were
greater
for
the
DMA
form
of
2,4­
D.
The
highest
TTR
level
for
2,4­
D
DMA
applied
as
part
of
a
combination
occurred
on
DAT
0.5.
The
TTR
levels
declined
to
the
LOQ
in
10
days
for
the
22
EHE
treatment,
7
days
for
the
DMA
treatment
and
5
days
for
the
DMA
combination
treatment.

Table
13
­
Dissipation
of
2,4­
D
Applied
to
Turf
Using
Various
Forms
(
Phase
1)

2,4­
D
Form
Application
Rate
(
lb
ae/
acre)
Maximum
TTR2
(
ug/
cm2)
Percent
Applied
as
TTR
Correlation
Coefficient
Half
Life
(
days)

EHE
DMA
DMA
Comb1
1.7
1.7
1.6
0.34
+
0.87
(
n=
3)
0.56
+
0.20
(
n=
3)
0.31
+
0.066(
n=
3)
1.8
2.9
1.7
0.96
(
n=
30)
0.90
(
n=
27)
0.91
(
n=
21)
1.2
0.83
0.53
1.
The
combination
included
2,4­
D
DMA,
MCPP­
p
and
dicamba.
2.
The
maximum
TTR
occurred
on
DAT
1
for
EHE
and
DMA.
The
maximum
TTR
for
the
DMA
combination
occurred
on
DAT
0.5.

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
2,4­
D
was
applied
in
combination
with
MCPP­
p
DMA
and
dicamba
DMA
All
of
the
applications
were
made
to
cool
season
fescue/
blue
grass
turf
plots
in
North
Carolina
using
a
ground­
boom
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
with
cotton
cloth.
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
82.8
+
11.5
(
n=
28)
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
recoveries
were
89.7
+
7.2
(
n=
6)
at
0.004
ug/
cm2
and
78.8
+
5.9
(
n=
6)
at
0.040
ug/
cm2.
When
considered
by
DAT,
the
recoveries
were
82.0
+
5.8
(
n=
6)
for
the
DAT
0
samples
and
86.5
+
10.6
(
n=
6)
for
the
DAT
6
samples.
The
raw
data
were
corrected
for
field
recovery
by
using
0.788
for
data
greater
than
0.040
ug/
cm2
and
0.897
for
data
less
than
0.040
ug/
cm2.

A
summary
of
the
results
are
shown
in
Table
14
and
a
more
detailed
listing
is
included
in
Appendix
F.
The
half
lives
ranged
from
0.29
to
0.32
days
and
were
calculated
based
upon
the
first
three
days
of
dissipation
because
the
TTRs
reached
the
LOQ
by
DAT
3.
23
Table
14
­
Dissipation
of
2,4­
D
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
1.76
1.76
1.76
0.23
+
0.035
(
n=
3)
0.25
+
0.064
(
n=
3)
0.17
+
0.025
(
n=
3)
1.0
1.3
0.87
0.79
(
n=
15)
0.90
(
n=
15)
0.95
(
n=
15)
0.31
0.29
0.32
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.

Determination
of
Transferable
Turf
Residues
on
Turf
Treated
with
2,4­
D
DMA,
MCPA
DMA,
2,4­
D
DMA
+
MCPP­
p
DMA
+
Dicamba
DMA
and
MCPA
DMA
+
MCPP­
p
DMA
+
2,4­
DP­
p­
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.
The
2,4­
D
DMA
was
applied
either
by
itself
(
Treatment
2)
or
in
combination
with
MCPP­
p
DMA
and
dicamba
DMA
(
Treatment
4).
The
applications
were
made
to
Kentucky
Bluegrass
turf
plots
in
Wisconsin
and
to
Dwarf
Fescue
turf
plots
in
California
using
ground­
boom
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
Phases
1
and
2
using
the
ORETF
roller
with
cotton
cloth.
Samples
were
collected
at
1,
4,
8,
12
and
24
HAT
and
2,
3,
4
and
7
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
for
the
California
site
data
was
104
+
11.5
percent
(
n=
17)
and
did
not
vary
significantly
with
respect
to
the
fortification
levels
which
ranged
from
1
to
1600X
LOQ.
The
concurrent
laboratory
recovery
for
the
Wisconsin
site
data
was
87.1
+
12.7
percent
(
n=
17)
and
did
not
vary
significantly
with
respect
to
the
fortification
levels
which
ranged
from
1
to
600X
LOQ.
Field
recovery
samples
were
prepared
in
the
same
manner
as
for
Phases
1
and
2
with
the
exception
that
a
different
fortification
solution
was
used.
In
Phases
1
and
2,
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.

A
summary
of
the
results
are
shown
in
Table
15
and
a
more
detailed
listing
is
included
in
Appendix
F.
The
TTR
values
declined
to
the
LOQ
by
DAT
1
in
Wisconsin
and
to
40X
LOQ
by
DAT
7
in
California.
The
California
TTRs
declined
steeply
during
DAT
1
and
at
a
much
slower
rate
during
DAT
1
through
7.
The
data
for
DAT
0.5
at
the
California
site
are
not
included
24
because
these
samples
were
collected
at
night
when
there
was
dew.

Table
15
­
Dissipation
of
2,4­
D
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
2
CA­
4
WI­
2
WI­
4
1.67
1.66
1.65
1.64
0.24
+
0.030
(
n=
3)
0.20
+
0.020
(
n=
3)
0.21
+
0.031
(
n=
3)
0.21
+
0.021(
n=
3)
1.3
1.1
1.1
1.1
0.78
(
n=
24)
0.91(
n=
24)
0.92
(
n=
15)
0.89
(
n=
15)
2.8
2.6
0.12
0.11
1.
Treatment
2
consisted
of
2,4­
D
by
itself.
Treatment
4
consisted
of
2,4­
D
with
MCPP­
p
and
dicamba
2.
The
maximum
TTR
occurred
on
HAT
1
for
the
both
CA
sites,
on
HAT
1
for
the
WI­
2
and
on
HAT
8
for
the
WI­
4
site.

Overall
Summary
and
Application
of
the
TTR
Data
A
detailed
listing
of
the
TTR
data
is
included
in
Appendix
F
and
a
summary
of
the
data
used
for
occupational
exposure
assessment
is
included
in
Table
16.
The
maximum
TTR
values
of
2.9%
of
the
application
rate
in
North
Carolina
and
1.3%
of
the
application
rate
in
California
were
used
for
assessing
exposures
in
humid
and
dry
regions,
respectively.
The
Wisconsin
data
were
not
used
because
the
rain
occurred
on
DAT
1
which
caused
the
TTRs
to
decline
to
the
LOQ
by
the
end
of
DAT
1.
The
dissipation
rates
were
not
used
because
the
MOEs
on
day
zero
were
greater
than
100.

Table
16
­
Summary
of
TTR
Data
Used
for
Occupational
Post
Application
Exposure
Assessment
NC
­
Phase
1
NC
­
Phase
2
CA
Conditions
No
Rain
Some
Rain
After
DAT
2
No
Rain
Application
Rate
(
lbs
ae/
acre)
1.72
1.76
1.67
Maximum
TTR
(
ug/
cm2)
0.56
0.25
0.24
Maximum
TTR
(
percent
of
applied)
2.9
­
Note
1
1.3
1.3
25
Assumptions
The
following
assumptions
were
made
regarding
occupational
post
application:


Short
term
risks
were
assessed
using
master
label
rates.


Intermediate
term
risks
were
assessed
using
average
application
rates
when
available.


The
transfer
coefficients
as
listed
in
Table
17
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,
from
further
analysis
of
studies
already
submitted
to
the
Agency,
and
from
studies
in
the
published
scientific
literature.


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


In
cases
where
applications
would
be
made
in
such
a
way
as
to
minimize
contact
with
crop
foliage
post
application
exposures
are
expected
to
be
negligible
and
are
not
assessed.
These
cases
are
included
in
Table
17.


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

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)
time
the
duration
worked
(
hr).
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,
particularly
when
the
pesticide
is
applied
outdoors
and
has
a
low
vapor
pressure.
The
vapor
pressure
of
2,4­
D
is
2.0e­
07
torr
at
20o
C.
26
Table
17
­
Post
Application
Exposure
Scenarios
and
Transfer
Coefficients
for
2,4­
D
Crop
Label
Directions
Post
Application
Exposure
Scenarios
Transfer
Coefficient
(
cm2/
hr)

Asparagus
Apply
immediately
after
cutting
before
regrowth
of
new
spears
or
post
harvest.
Spears
contacted
the
spray
may
be
malformed
and
off
flavor.
Do
not
exceed
two
applications
per
crop.
Do
not
apply
within
30
days
of
previous
application.
Pre
Harvest
Interval
(
PHI)
=
3
days
None1,2
Blueberries
­
High
Bush
Make
directed
or
shielded
applications
in
the
spring.
Make
directed
applications
to
row
middles
in
summer
or
fall
after
harvest.
None1
Blueberries
­
Low
Bush
Make
directed
wipe
or
spot
applications
when
weed
tops
are
above
crop.
Make
directed
application
to
cut
hardwoods
in
row
middles
in
summer
or
fall
after
harvest.
Avoid
contact
with
blueberry
foliage
and
apply
only
in
the
non­
bearing
year.
None1
Cereal
Grains
Apply
Post­
emergence
rate
(
1.25
lb
ae/
acre)
after
grain
is
fully
tillered
(
4­
8"
high).
Apply
Pre­
harvest
rate
(
0.5
lb
ae/
acre)
at
the
dough
stage.
PHI
=
14
days
Low
Exposure
Scenarios
­
Irrigation,
scouting,
immature
plants
Medium
Exposure
Scenarios
­
Same
as
above
on
mature
plants
100
1500
Citrus
Applied
to
trees
to
prevent
fruit
drop
and
increase
fruit
size.
PHI
=
7
days.
None3
Conifer
Plantations
Apply
over
the
top
to
firs
prior
to
bud
break
or
after
complete
bud
set
and
hardening
in
the
late
summer
or
fall.
Avoid
treatment
during
the
year
of
harvest.
Directed
sprays
may
be
made
to
weeds
in
Christmas
tree
plantations
of
all
conifer
species,
but
the
spray
must
not
contact
tree
foliage
as
injury
may
occur.
None1
Corn,
Field
and
Popcorn
Apply
Preemergence
rate
(
1.0)
before
corn
emerges.
Apply
Post
Emergence
rate
(
0.5)
when
corn
is
less
than
8"
tall
or
by
using
drop
nozzles.
Apply
Preharvest
rate
(
1.5)
after
dough
or
at
denting
stage.
Not
applied
in
tassel
to
dent
stage.
PHI
=
7
days.

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
1000
NA4
Corn,
Sweet
Apply
Preemergence
rate
(
1.0)
before
corn
emerges.
Apply
Post
Emergence
rate
(
0.5)
when
corn
is
less
than
8"
tall
or
by
using
drop
nozzles.
Preharvest
rate
not
used.
PHI
=
45
days.

Low
Exposure
Scenarios
­
Scouting,
immature
plants
100
Cranberries
Make
broadcast
applications
at
dormant
rate
(
4.0)
in
the
dormant
season.
Make
directed
wipe
or
spot
applications
at
the
postemergence
rate
(
1.2)
when
weed
tops
are
above
crop.
PHI
=
30
days.
None1
Filberts
Spray
on
suckers
that
arise
from
the
base
of
the
trees.
None1
Grapes
Use
hooded
boom
sprayer
or
equivalent
to
direct
coarse
spray
to
weeds
and
minimize
potential
contact
with
grape
foliage,
shoots
or
stems..
None1
Orchard
Floors
For
control
of
weeds
on
orchard
floors.
PHIs
are
14
days
for
pome
fruits,
40
days
for
stone
fruits
and
60
days
for
nuts.
None1
Pasture,
Rangeland,
Grassland
PHI
=
7
days
None1
Potatoes
Make
first
application
when
potatoes
are
in
the
pre­
bud
stage
(
7
to
10"
high)
and
second
application
is
made
10
to
14
days
later.
PHI
=
45
days.
None3
Rice,
Wild
Applied
to
rice
in
the
1
to
2
aerial
leaf
through
early
tillering
stage.
Not
applied
after
boot
stage.
PHI
=
60
days.
See
Below
Table
17
­
Post
Application
Exposure
Scenarios
and
Transfer
Coefficients
for
2,4­
D
Crop
Label
Directions
Post
Application
Exposure
Scenarios
Transfer
Coefficient
(
cm2/
hr)

27
Rice,
Conventional
Apply
Preplant
rate
(
1.0)
2
to
4
weeks
prior
to
planting.
Apply
Postemergence
rate
(
1.5)
at
the
late
tillering
stage
usually
6
to
9
weeks
after
emergence.
Do
not
apply
after
panicle
initiation.
PHI
=
60
days.

Low
Exposure
Scenarios
­
Irrigation,
scouting,
immature
plants
Medium
Exposure
Scenarios
­
Same
as
above
on
mature
plants
100
1500
Sorghum,
Grain
or
Forage
Apply
when
sorghum
is
6
to
15"
tall.
If
sorghum
is
taller
than
8"
use
drop
nozzles
and
keep
spray
off
the
foliage.

Low
Exposure
Scenarios
­
Scouting
immature
plants
High
Exposure
Scenarios
­
Irrigation
and
scouting
mature
plants
100
NA5
Soybeans
Apply
for
preplant
burndown
not
less
than
7
to
30
days
prior
to
planting.
None1
Strawberries
Apply
when
strawberries
have
gone
into
dormancy
or
after
last
picking.
None1
Sugarcane
Apply
before
canes
appear
for
control
of
emerged
weeds.
Apply
after
canes
emerge
and
through
canopy
closure.

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
4.0
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.

3.
The
application
rates
are
extremely
low
(
0.1
lb
ae/
acre
for
citrus
and
0.07
lb
ae/
acre
for
potatoes).

4.
Detasselling
TC
does
not
apply
to
field
corn
because
label
prohibits
application
during
tassel
to
dent
stage.

5.
This
TC
does
not
apply
because
2,4­
D
is
applied
when
the
plants
are
immature.

2.2.3
Exposure
and
Risk
Estimates
A
summary
of
the
worker
risks
for
short
term
post
application
exposures
is
given
in
Table
18
and
the
calculations
are
included
in
Appendix
C.
All
of
the
short
term
MOEs
are
above
100
on
day
zero
which
indicates
that
the
risks
are
not
of
concern.
The
intermediate
term
MOEs
as
shown
in
Table
19
and
Appendix
D
are
also
all
above
100
on
day
zero.
28
Table
18
­
2,4­
D
Postapplication
Short
Term
Worker
Risks
Crop
Group
ShortTerm
MOE
on
Day
0
Application
Rate
(
lb
a.
e./
acre)
Low
Exposure
Scenarios*
Medium
Exposure
Scenarios*
High
Exposure
Scenarios*

Field/
row
crop,
low/
med
(
cereal
grains)
1.25
12,000
770
NA
Field/
row
crop,
low/
med
(
rice)
1.5
9,600
640
NA
Field/
row
crop,
tall
(
corn)
Pre­
harvest
rate
for
field
corn
Post­
emergence
rate
for
sweet
corn
1.5
0.5
9,600
28,000
2,400
7,200
960
NA
Field/
row
crop,
tall
(
sorghum)
1.0
14,000
3,600
NA
Sugarcane
2.0
NA
720
360
Turf
­
California
Turf
­
North
Carolina
2.0
2.0
3,300
1,500
NA
NA
1,600
750
*
Task
descriptions
for
each
crop
and
exposure
scenario
are
included
in
Table
17.

Table
19
­
2,4­
D
Postapplication
Intermediate
Term
Worker
Risks
Crop
Group
Intermediate
Term
MOE
on
Day
0
Application
Rate+
(
lb
a.
e./
acre)
Low
Exposure
Scenarios*
Medium
Exposure
Scenarios*
High
Exposure
Scenarios*

Field/
row
crop,
low/
med
(
cereal
grains)
0.5
20,000
1,300
NA
Field/
row
crop,
low/
med
(
rice)
0.92
11,000
730
NA
Field/
row
crop,
tall
(
field
corn)
0.44
23,000
5,700
2,300
Field/
row
crop,
tall
(
sweet
corn)
0.48
22,000
5,500
NA
Field/
row
crop,
tall
(
sorghum)
0.46
22,000
5,500
NA
Sugarcane
0.75
NA
1,300
670
Turf
­
California
Turf
­
North
Carolina
2.0
2.0
2,800
1,000
NA
NA
1400
520
+
Average
application
rates
as
reported
in
the
QUA
report
or
NASS
report
were
used
when
available.
*
Task
descriptions
for
each
crop
and
exposure
scenario
are
included
in
Table
17.

2.2.4
Risk
Characterization
All
of
the
post
application
MOEs
are
substantially
greater
than
100
which
means
that
the
risks
are
not
of
concern.

2.3
­
Residential
Applicator
Exposures
and
Risks
29
According
to
the
EPA
Pesticide
Sales
and
Usage
Report
for
1998/
1999,
2,4­
D
is
the
most
commonly
used
conventional
pesticide
active
ingredient
in
the
home
and
garden
market
sector
with
7
to
9
million
pounds
applied
per
year.
It
is
also
the
most
commonly
used
conventional
active
ingredient
in
the
Industry/
Commercial/
Government
market
section
with
17
to
20
million
pound
applied
per
year.
This
segment
includes
applications
to
homes
and
gardens
by
professional
applicators.

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
phenoxy
herbicides
such
as
MCPP­
p
and
MCPA.
Both
spot
and
broadcast
treatments
are
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
for
hard
to
kill
weeds
in
two
to
three
weeks.

2.3.1
­
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
the
following
study
which
has
recently
been
purchased
by
the
ORETF:


Carbaryl
Mixer/
Loader/
Applicator
Exposure
Study
during
Application
of
RP­
2
Liquid
(
21%)
Sevin
(
r)
Ready
to
Use
Insect
Spray
or
Sevin
10
Dust
to
Home
Garden
Vegetables.
Agrisearch
Study
No.
1519.
EPA
MRID
444598­
01.
Report
dated
August
22,
1998,
Author;
Thomas
C.
Mester,
PhD.,
Sponser:
Rhone
Poulenc
Ag
Company
This
study
involved
low
pressure
handwand
and
RTU
trigger
sprayer
application
of
Sevin(
R)
30
which
contains
21%
carbaryl
to
home
vegetable
plants.
Applications
were
made
by
volunteers
to
two
18
foot
rows
of
tomatoes
and
one
18
foot
row
of
cucumbers
at
a
test
field
in
Florida.
A
total
of
40
replicates
were
conducted.
Latex
gloves
were
worn
for
twenty
of
the
replicates
and
no
gloves
were
worn
for
the
other
twenty
replicates.
Each
replicate
opened
the
end
use
product
and
applied
it
to
the
vegetable
rows,
after
which
the
dosimeters
were
collected.
Inhalation
exposure
was
monitored
in
the
breathing
zone
with
personal
air
sampling
pumps
and
OVS
sampling
tubes.
Dermal
exposure
was
monitored
by
the
extraction
of
carbaryl
from
inner
and
outer
cotton
full
body
dosimeters,
face
neck
wipes,
and
glove
and
hand
washes.

The
average
field
fortification
recoveries
for
the
full
body
dosimeters
were
84.3%
for
the
inner
and
77.7
%
for
the
outer.
Face/
neck
wipe
field
recoveries
were
84.8%
and
handwash
and
OVS
tube
field
recoveries
were
greater
than
90
%.
Laboratory
method
validation
for
each
sampling
matrix
fell
within
the
acceptable
range
of
70
%
to
120%.
The
limit
of
quantitation
(
LOQ)
was
1.0
ug/
sample
for
all
media
except
the
OVS
tubes
where
the
LOQ
was
0.01
ug/
sample.

Dermal
exposure
was
determined
by
adding
the
values
from
the
bare
hand
rinses,
face/
neck
wipes,
outer
dosimeter
lower
legs
and
arms,
inner
dosimeter
torso
and
inner
dosimeter
upper
legs
and
upper
arms.
This
accounts
for
the
residential
applicator
wearing
a
short
sleeved
shirt
and
short
pants.
The
unit
exposures
are
presented
in
Table
20.

Table
20
­
Unit
Exposure
Values
For
Trigger
and
Pump
Sprayer
Application
(
MRID
444598­
01)
Scenario
Dermal
Unit
Exposure
(
mg/
lb
ai
handled)
Inhalation
Unit
Exposure
(
ug/
lb
ai
handled)
Average
Geo.
Mean
Median
Average
Geo.
Mean
Median
Trigger
Sprayer
80
53
53
0.096
0.067
0.034
Hand
Held
Pump
Sprayer
56
38
35
0.012
0.030
0.011
Assumptions
regarding
Residential
Applicators

Clothing
would
consist
of
a
short­
sleeved
shirt,
short
pants
and
no
gloves.


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


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.


The
application
rate
is
2.0
lb
ae/
acre
as
listed
on
the
master
label.

2.3.2
Exposure
and
Risk
Estimates
The
MOE
calculations
are
included
in
Appendix
E
and
a
summary
is
included
in
Table
21.
All
of
the
MOEs
exceed
the
target
MOE
of
1000
and
are
not
of
concern.
31
Table
21
­
2,4­
D
Short
Term
MOEs
for
Homeowner
Applications
to
Lawns
Scenario
Application
Rate
(
lbs
ae/
acre)
Treated
Area
(
acres/
day)
MOE
1
Hand
Application
of
Granules
2.0
0.023
4,600
2
Belly
Grinder
Application
2.0
0.023
5,100
3.
Load/
Apply
Granules
with
a
Broadcast
Spreader
2.0
0.5
38,000
4.
Mix/
Load/
Apply
with
a
Hose­
end
Sprayer
(
Mix
your
own)
2.0
0.5
2,300
5.
Mix/
Load/
Apply
with
a
Hose­
end
Sprayer
(
Ready
to
Use)
2.0
0.5
9,300
6.
Mix/
Load/
Apply
with
Hand
Held
Pump
Sprayer
2.0
0.023
15,000
7.
Mix/
Load/
Apply
with
Ready
to
Use
Sprayer
2.0
0.023
10,000
Note:
1000
square
feet
equals
0.023
acres
2.3.3
Risk
Characterization
The
master
label
application
rate
of
2.0
lb
ae/
acre
was
used
for
all
assessments.
Many
of
the
labels
have
application
rates
in
the
range
of
0.5
to
1.5
lb
ae/
acre
because
2,4­
D
is
formulated
with
other
phenoxy
herbicides
such
as
MCPP­
p
and
MCPA.

The
2,4­
D
Task
force
is
in
the
process
of
completing
probabilistic
assessments
of
residential
handler
scenarios
using
the
CARES
model,
which
has
been
reviewed
by
the
FIFRA
Science
Advisory
Panel.
The
Agency
will
evaluate
the
inputs
and
analysis
of
the
CARES
model
when
they
are
submitted
and
if
all
appropriate
criteria
for
submission
have
been
met.
For
example,
the
public
availability
of
any
model
used
for
probabilistic
assessments
is
required.

2.4
­
Residential
Turf
Post
Application
Exposure
and
Risks
2.4.1
Exposure
Scenarios,
Data
Sources
and
Assumptions
The
following
exposure
scenarios
are
assessed
for
residential
post
application
risks
Toddlers
Playing
on
Treated
Turf
Adults
Performing
Yardwork
on
Treated
Turf
Adults
Playing
Golf
on
Treated
Turf
Data
Sources:

There
are
three
turf
transferable
residue
studies
that
were
submitted
by
the
Broadleaf
Turf
Herbicide
TTR
Task
Force.
These
studies
were
described
in
Section
2.2.2.
32
Overall
Summary
and
Application
of
the
TTR
Data
Regression
analysis
of
the
TTR
data
is
included
in
Appendix
F
and
a
summary
of
the
data
used
for
exposure
assessment
is
included
in
Table
22.
The
maximum
TTR
value
of
2.9%
percent
of
the
application
rate
is
used
for
assessing
acute
exposures.
The
dissipation
rate
for
humid
regions
without
rain
is
derived
from
the
North
Carolina
Phase
1
study
in
which
the
DMA
form
of
2,4­
D
was
applied
by
itself.
This
dissipation
rate
is
similar
to
the
rates
observed
when
the
EHE
form
of
2,4­
D
was
applied
or
when
the
DMA
form
of
2,4­
D
is
applied
with
MCPP­
p
and
dicamba.
The
dissipation
rate
for
the
dry
regions
is
derived
from
the
California
TTR
site
data
in
which
the
DMA
form
of
2,4­
D
was
applied
with
MCPP­
p
and
dicamba.
The
dissipation
rate
for
humid
regions
with
rain
is
derived
from
the
North
Carolina
Phase
2
data
in
which
the
DMA
form
of
2,4­
D
was
applied
with
MCPP­
p
and
dicamba.

Table
22
­
Summary
of
TTR
Data
Used
for
Residential
Post
Application
Exposure
Assessment
NC
­
Phase
1
NC
­
Phase
2
CA
Conditions
No
Rain
Some
Rain
After
DAT
2
No
Rain
Application
Rate
(
lbs
ae/
acre)
1.72
1.76
1.67
Maximum
TTR
(
ug/
cm2)
0.56
0.25
0.24
Maximum
TTR
(%
of
applied)
2.9
­
Note
1
1.3
1.3
Initial
TTR
(
ug/
cm2)
0.31
0.20
0.20
Initial
TTR
(%
of
applied)
1.6
­
Note
2
1.0
­
Note
2
1.1
­
Note
2
Semi­
log
Slope
Factor
­
0.83
­
2.3
­
0.26
Seven
Day
Average
TTR
(
ug/
cm2)
0.080
0.034
0.10
Seven
Day
Average
TTR
(%
of
applied)
0.41
­
Note
2
0.18
­
Note
2
0.56
­
Note
2
Days
to
LOQ
7
3
greater
than
7
Note
1
­
This
value
was
used
to
assess
1
day
acute
and
one
day
short
term
exposures.
Note
2
­
These
values
were
used
to
assess
seven
day
average
short
term
exposures.
33
General
Assumptions
The
following
assumptions
and
standard
values
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.


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


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


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


Three
year
old
toddlers
are
expected
to
weigh
15
kg.


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.


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.


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


Toddlers
are
assessed
using
a
transfer
coefficient
of
5,200
cm2/
hour.


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


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


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

Assumptions
Specific
to
2,4­
D
The
following
assumptions
that
are
specific
to
2,4­
D
are
used
for
assessing
residential
post
application
exposures.


The
master
label
application
rate
of
2.0
lbs
ae/
acre
was
used.


The
exposure
following
the
application
of
granular
formulations
was
not
assessed
because
there
were
no
TTR
data
submitted
for
granular
formulations.
It
was
assumed
this
exposure
would
be
less
than
or
equal
to
the
exposure
from
liquid
formulations.
Calculation
Methods
34
The
above
factors
were
used
in
the
standard
SOP
formulae
to
calculate
the
exposures.
These
formulas
are
described
in
Appendix
A.
MOEs
were
calculated
for
acute
toddler
exposures
using
the
maximum
TTR
value
along
with
the
acute
dietary
NOAEL
of
67
mg/
kg/
day
as
selected
by
the
HIARC
(
see
Table
3).
This
NOAEL
was
adapted
to
acute
dermal
exposures
by
using
the
dermal
absorption
factor
of
5.8
percent
to
account
for
route
to
route
extrapolation.
The
MOEs
for
toddler
short
term
exposures
were
calculated
using
the
seven
day
average
TTR
value
because
the
short
term
NOAEL
was
based
upon
decreased
body
weight
gain
which
occurred
after
several
days
of
exposure.
MOEs
for
acute
and
adult
short
term
exposures
were
calculated
using
the
maximum
TTR
value
because
the
acute
and
short
term
NOAELs
are
the
same
and
are
based
upon
the
developmental
effects
which
could
have
occurred
following
one
day
of
exposure.

2.4.2
Exposure
and
Risk
Estimates
The
MOEs
are
summarized
in
Table
23
and
24
and
the
detailed
calculations
are
included
in
Appendix
G.
All
of
the
MOEs
meet
or
exceed
the
target
MOE
of
1000.

Table
23
­
Toddler
MOEs
for
Exposure
to
Turf
Treated
with
2,4­
D
Application
Rate
(
lbs
ae/
acre)
TTR
(
ug/
cm2)
Semilog
Slope
R2
Dermal
MOE
Hand­
to
Mouth
MOE
Object
to
Mouth
MOE
Soil
Ingestion
MOE
Total
MO
E
Acute
Toddler
Risks
Using
the
Maximum
TTR
(
North
Carolina
Trial
1
using
2,4­
D
DMA)

DAT
0
2.0
0.67
(
MAX)
N/
A
N/
A
2,500
2,200
9,000
>
100,000
1,040
Short
Term
Toddlers
Risks
Using
California
TTR
Data
(
DMA
Mix,
No
Rain)

DAT
0
to
DAT
6
2.0
0.12
(
AVG)
­
0.26
0.83
5,000
1,600
6,400
>
100,000
1,000
Short
Term
Toddler
Risks
Using
North
Carolina
TTR
Data
from
Trial
1
(
DMA
and
DMA
Mix,
No
Rain)

DAT
0
to
DAT
6
2.0
0.093
(
AVG)
­
0.83
0.81
6,700
3,300
13,000
>
100000
1,900
Short
Term
Toddler
Risks
Using
North
Carolina
TTR
Data
from
Trial
2
(
DMA
Mix,
Some
Rain)

DAT
0
to
DAT
6
2.0
0.039
(
AVG)
­
2.3
0.87
16,000
5,200
21,000
>
100000
3,300
The
acute
NOAEL
is
67
mg/
kg/
day
for
neurotoxic
effects
observed
in
acute
neurotoxicity
study.
The
short
term
NOAEL
is
25
mg/
kg/
day
for
maternal
effects
observed
in
the
developmental
study.
35
Table
24:
Adult
Acute/
Short
Term
MOEs
for
Exposure
to
Turf
Treated
with
2,4­
D
Exposure
Scenario
Application
Rate
(
lbs
ae/
acre)
TTR
(
ug/
cm2)
Acute/
Short
Term
Dermal
MOEA
on
Day
0
Heavy
Yardwork
Playing
Golf
2.0
0.67
1300
19000
A.
The
acute/
short
term
NOAEL
is
25
mg/
kg/
day
for
developmental
effects
observed
in
the
developmental
study.

2.4.3
Risk
Characterization
and
Comparison
to
Biomonitoring
Data
Risk
Characterization
The
calculation
of
acute
MOEs
using
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
2,4­
D
risk
assessment
team
decided
that
the
previous
approach
would
greatly
overestimate
the
short
term
toddler
risk
because
the
short
term
endpoint
was
based
upon
maternal
effects
that
would
only
occur
after
several
days
of
exposure.
The
team
also
decided
that
the
single
day
toddler
exposures
as
represented
by
the
maximum
TTR
values
would
be
more
appropriately
assessed
using
the
acute
endpoint.
The
short
term
toddler
exposures
were
assessed
using
the
seven
day
average
TTR
values
because
the
endpoint
occurred
after
following
several
days
of
exposure
and
because
the
TTR
data
were
collected
during
a
seven
day
time
period.
The
acute/
short
term
adult
exposures
were
assessed
using
the
maximum
TTR
value
because
the
acute/
short
term
endpoint
was
a
development
effect
that
could
have
occurred
following
a
single
day
of
exposure.
Although
the
developmental
effect
only
applies
to
females
of
reproductive
age,
the
Agency
currently
does
not
calculate
separate
MOEs
for
male
and
females
because
it
not
practical
to
exclude
females
from
residential
exposures.

The
master
label
application
rate
of
2.0
lb
ae/
acre
was
used
for
all
assessments.
Many
of
the
labels
have
application
rates
in
the
range
of
0.5
to
1.5
lb
ae/
acre
because
2,4­
D
is
formulated
with
other
phenoxy
herbicides
such
as
MCPP­
p
and
MCPA.

The
2,4­
D
Task
force
is
also
in
the
process
of
completing
probabilistic
assessments
of
residential
turf
post
application
scenarios
using
the
CARES
model.

Comparison
to
Biomonitoring
Data
Researchers
at
the
Canadian
Centre
for
Toxicology
conducted
2,4­
D
biomonitoring
on
adult
volunteers
who
were
exposed
to
2,4­
D
while
performing
controlled
activities
for
one
hour
on
turf
treated
with
0.88
lb
ae/
acre
2,4­
D
(
Harris
and
Solomon
1992).
The
controlled
activities
were
conducted
at
1
hour
after
treatment
(
HAT)
and
at
24
HAT.
Ten
volunteers
participated
in
36
the
study.
Five
volunteers
wore
long
pants,
a
tee
shirt,
socks
and
closed
footwear.
The
other
five
wore
shorts
and
a
tee
shirt
and
were
barefoot.
The
volunteers
walked
on
the
turf
for
a
period
of
5
minutes
and
then
sat
or
lay
on
the
area
for
5
minutes
and
then
continued
in
this
fashion
for
50
more
minutes.
At
the
end
of
the
exposure
period
the
volunteers
were
allowed
to
wash
their
hands
and
were
served
a
picnic
lunch
on
an
adjacent
unsprayed
area.
Each
volunteer
collected
all
urine
for
the
next
96
hours
immediately
following
the
exposure.
A
baseline
urine
sample
was
also
collected
on
morning
of
the
exposure
day
to
account
for
previous
2,4­
D
exposures
and
to
use
for
spike
samples.
The
spike
samples
were
prepared
by
adding
22
ug
of
2,4­
D
to
100
ml
subsamples
of
the
baseline
urine
samples
and
were
stored
by
the
volunteers
in
the
same
manner
as
the
daily
urine
samples.
The
results
indicated
that
detectable
levels
of
2,4­
D
were
found
only
in
the
volunteers
who
wore
shorts
without
shoes
and
who
were
exposed
at
1
HAT.
The
highest
exposure
of
426
ug
was
detected
in
a
HAT
1
volunteer
who
removed
his
shirt
during
the
exposure
period.
The
1
HAT
volunteers
who
wore
long
pants
and
shoes
and
all
of
the
24
HAT
volunteers
had
urinary
2,4­
D
levels
that
were
below
the
limit
of
detection
of
5
ug/
liter.
The
creatinine
values,
which
were
in
the
normal
range
and
showed
little
daily
variation,
indicated
that
the
urine
collection
was
complete.
The
spike
samples
indicated
an
average
recovery
of
92.5
+
14.5
percent.
One
of
the
1
HAT
volunteers
and
one
of
the
24
HAT
volunteers
had
detectable
levels
of
2,4­
D
in
the
baseline
sample.

As
discussed
in
a
recent
review
of
pesticide
biomonitoring
(
Maroni
et
al.
2000)
most
of
the
phenoxy
herbicide
dose
is
excreted
in
the
urine
as
unmodified
compounds
or
conjugate
derivatives.
As
part
of
the
skin
absorption
study
of
various
pesticides
including
2,4­
D
(
Maibach
and
Feldmann,
1974)
intravenous
dosing
was
conducted
to
measure
urinary
excretion.
One
hundred
percent
(
n=
6)
of
the
administered
2,4­
D
dose
was
recovered
within
120
hours
of
administration
and
98
percent
of
the
dose
was
recovered
within
96
hours.
The
dermal
absorption
portion
of
this
study
indicated
that
5.8
+
2.4
percent
of
the
topical
dose
was
recovered
within
120
hours
and
5.2
percent
of
the
topical
dose
was
recovered
within
96
hours.
In
a
more
recent
study
of
2,4­
D
skin
absorption
(
Harris
and
Solomon,
1992)
80.8
+
13.3
percent
(
n=
10)
of
the
urinary
excretion
of
a
topically
applied
dose
occurred
during
the
first
96
hours
and
urinary
2,4­
D
was
approaching
the
limit
of
detection
at
144
hours.
It
should
be
noted
that
the
applied
dose
(
ug/
cm2)
in
the
Harris
and
Solomon
study
was
280
times
that
of
the
applied
dose
in
the
Maibach
and
Feldmann
study.
The
applied
dose
of
in
the
Maibach
study
(
4
ug/
cm2)
is
also
closer
to
the
estimated
dermal
exposure
of
1.8
ug/
cm2
for
a
70
kg
adult
with
an
exposed
skin
surface
area
of
11000
cm2.
The
dermal
exposure
in
ug
=
0.672
ug/
cm2
*
2
hours
exposure
*
14500
cm2/
hr
and
the
dermal
exposure
in
ug/
cm2
=
19500
ug/
11000
cm2.

The
results
of
the
biomonitoring
study
were
used
to
calculated
MOEs
by
assuming
that
all
of
the
urinary
2,4­
D
measured
in
the
96
hours
after
the
exposure
period
was
the
result
of
the
turf
exposure.
This
assumption
is
protective
because
2,4­
D
exposures
due
to
inhalation
and
due
to
food
and
water
ingestion
would
be
counted
as
dermal
exposure.
The
biomonitoring
results
were
adjusted
by
a
factor
of
two
to
account
the
SOP
assumption
of
two
hours
of
daily
exposure
vs
one
hour
of
exposure
during
the
study
and
factor
of
2.3
to
account
for
an
application
rate
of
2.0
lbs
ae/
acre
vs
0.88
lb
ae/
acre
applied
during
the
study.
37
The
MOEs
for
the
DAT
1
volunteers
who
wore
shorts
and
no
shoes
ranged
from
1000
to
26000
with
the
lowest
MOE
corresponding
to
the
volunteer
who
removed
his
shirt
during
the
exposure
period.
The
MOEs
for
the
remaining
volunteers
ranged
from
17000
to
27000.
The
MOEs
are
listed
in
Table
25.

Table
25
­
Residential
Post
Application
MOES
on
2,4­
D
Treated
Turf
Based
Upon
Biomonitoring
Data
Exposure
Beginning
at
One
Hour
Post
Application
Volunteer
Clothing
BW
Measured
2,4­
D
DoseA
Adjusted
2,4­
D
DoseB
Adjusted
2,4­
D
dose
MOEC
1
2
3
4
5
Avg
GM
shorts/
barefoot
shorts/
barefoot
shorts/
barefoot
shorts/
barefoot
shorts/
barefootE
100
kg
95.5
63.6
45.5
79.5
0.153
mg
0.020
(
Note
D)
0.020
0.103
0.426
0.70
mg
0.091
0.091
0.47
1.9
0.0070
mg/
kg/
day
0.00095
0.0014
0.0103
0.0244
3600
26000
17000
2400
1000
10000
5300
6
7
8
10
Avg
GM
pants/
shoes
pants/
shoes
pants/
shoes
pants/
shoes
77.3
kg
68.2
72.7
79.5
0.020
mg
0.020
0.020
0.020
0.091mg
0.091
0.091
0.091
0.0012
mg/
kg/
day
0.0013
0.0013
0.0011
21000
19000
19000
23000
20000
20000
Exposure
Beginning
at
24
Hours
Post
Application
Volunteer
Clothing
BW
Measured
2,4­
D
DoseA
Adjusted
2,4­
D
DoseB
Adjusted
2,4­
D
dose
MOEC
1
2
3
4
5
Avg
shorts/
barefoot
shorts/
barefoot
shorts/
barefoot
shorts/
barefoot
shorts/
barefoot
100
kg
77.3
63.6
79.5
72.7
0.020
mg
0.020
0.020
0.020
0.020
0.091mg
0.091
0.091
0.091
0.091
0.00091
mg/
kg/
day
0.0012
0.0014
0.0011
0.0013
27000
21000
17000
22000
20000
22000
6
7
8
10
Avg
pants/
shoes
pants/
shoes
pants/
shoes
pants/
shoes
75
kg
67.3
65.9
100
0.020
mg
0.020
0.020
0.020
0.091mg
0.091mg
0.091mg
0.091mg
0.0012
mg/
kg/
day
0.0014
0.0014
0.00091
21000
18000
18000
27000
21000
Notes
A.
Study
conditions
included
one
hour
of
exposure
on
turf
treated
with
0.88
lb
ae/
acre
B.
Adjusted
to
account
for
two
hours
of
exposure
and
an
application
rate
of
2.0
lb
ae/
acre.
C.
MOEs
were
calculated
using
a
NOAEL
of
25
mg/
kg/
day.
D.
Measured
doses
of
0.02
mg
represent
non­
detect
values
where
the
LOD
is
5
ug/
liter
and
the
sample
volume
is
4
litres.
The
sample
volume
of
4
litres
is
based
upon
an
average
urinary
output
of
1
litre
per
day
times
4
days.
E.
This
volunteer
removed
his
shirt
during
the
exposure
period.
38
2.5
­
Recreational
Swimmer
Post
Application
Exposure
and
Risks
The
master
label
indicates
that
2,4­
D
can
be
used
for
aquatic
weed
control
of
surface
weeds
such
as
Water
Hyacinth
and
submersed
weeds
such
as
Eurasian
Milfoil.
Surface
weeds
are
controlled
by
foliar
applications
at
a
maximum
rate
of
2.0
lb
ae/
acre.
Submersed
weeds
are
controlled
by
subsurface
injection
of
liquids
to
achieve
a
target
concentration
of
2
to
4
ppm
in
the
water
column
surrounding
the
weeds.
This
requires
5.4
to
10.8
lb
ae
per
acre
foot
of
water
depth
(
i.
e.
5.4
lbs
ae
would
be
required
to
achieve
2
ppm
in
a
one
acre
pond
that
has
an
average
depth
of
1
foot).
Granular
formulations
of
BEE
(
Aquakleen
and
Navigate)
are
also
used
to
control
submersed
weeds.
The
granular
formulations
are
made
with
heat
treated
attaclay
granules
that
resists
rapid
decomposition
in
water
and
release
the
herbicide
into
the
root
zone.

Although
many
herbicide
treatments
are
applied
to
aquatic
areas
where
recreational
swimming
is
not
likely
to
occur,
some
of
the
subsurface
treatments
are
made
at
recreational
lakes.
These
treatments
are
made
because
the
Eurasian
Milfoil
interferes
with
recreation
and
other
activities.
This
problem
is
particularly
prevalent
in
the
northern
states
such
as
Minnesota
and
Washington
and
in
the
New
England
region.

2.5.1
Exposure
Scenarios,
Data
Sources
and
Assumptions
Scenarios
The
following
exposure
scenarios
are
assessed
for
recreational
swimmers.

Adult
Recreational
Swimmer
Child
Recreational
Swimmer
Assumptions
The
following
assumptions
were
used
for
the
assessment
of
swimmer
risks.
Many
of
these
assumptions
were
taken
from
the
Residential
SOPs
and
are
also
used
in
the
SWIMODEL.


The
skin
surface
area
of
adults
is
assumed
to
be
21,000
cm2
as
cited
in
the
Residential
SOPs.
This
is
the
95th
percentile
value
for
females
(
EPA
Exposure
Factors
Handbook,
1997).


The
body
weight
for
children
is
assumed
to
be
22
kg
as
cited
in
the
Residential
SOPs.
This
is
a
mean
value
for
6
year
old
children.


The
skin
surface
area
for
children
is
assumed
to
be
9,000
cm2
as
cited
in
the
Residential
SOPs.
This
is
the
90th
percentile
value
for
male
and
female
children.


The
assumed
mean
ingestion
rate
is
0.05
liters
per
hour
for
both
adults
and
children
as
cited
in
the
Residential
SOP.
This
value
may
be
greater
for
young
children
playing
in
water
and
accidentally
ingesting
a
remarkable
quantity
of
water
(
U.
S.
EPA
SAP,
1999).
39

The
exposure
time
is
assumed
to
be
3
hours
per
day.
This
is
the
90th
percentile
value
for
time
spent
swimming
in
a
freshwater
pool.
(
EPA
Child
Specific
Exposure
Factors
Handbook,
2002).


The
body
weight
for
female
adult
acute
exposures
is
assumed
to
be
60
kg.


The
body
weight
for
male
adult
acute
exposures
is
assumed
to
be
70
kg.


The
body
weight
for
adult
short
term
exposure
is
assumed
to
be
60
kg
because
the
endpoint
is
gender
specific.


The
target
concentration
of
4
mg/
liter
(
4
ppm)
is
from
the
master
label.


The
target
concentration
of
2
mg/
liter
(
2
ppm)
is
from
use
information.


Risks
were
not
calculated
for
foliar
treatments
because
the
application
rate
of
2.0
lb
ae/
acre
would
result
in
water
concentration
of
only
0.25
ppm
in
a
three
foot
water
column
even
if
all
of
the
spray
were
to
run
off
the
leaves
into
the
water.

Calculation
Methods
The
above
factors
were
used
in
the
SWIMODEL
formulae
for
dermal
and
ingestion
exposure
which
are
described
in
Appendix
A.
The
SWIMODEL
formulas
for
the
other
dermal
pathways
(
aural,
buccal/
sublingual
and
orbital/
nasal)
were
not
used
because
these
formulas
are
based
upon
recreational
swimmers
in
swimming
pools
who
swim
with
their
heads
partially
immersed.
It
is
anticipated
that
recreational
swimmers
in
weed
infested
areas
would
be
less
likely
to
swim
with
their
heads
immersed
than
recreational
swimmers
in
weed­
free
swimming
pools.
In
addition,
the
formulas
for
the
buccal/
sublingual
and
orbital/
nasal
pathways
contain
a
default
absorption
factor
of
0.01
which
is
based
upon
the
absorption
of
nitroglycerin.
This
factor
would
greatly
overestimate
the
risk
of
2,4­
D
exposure
because
2,4­
D
is
absorbed
at
a
much
lower
rate.

MOEs
were
calculated
for
children's
acute
exposures
using
the
target
water
concentration
(
i.
e.
the
maximum
water
concentration)
along
with
the
acute
NOAEL
of
67
mg/
kg/
day.
MOEs
for
children's
short
term
exposures
were
calculated
using
the
target
water
concentration
(
because
there
was
insufficient
data
to
define
a
dissipation
rate)
along
with
the
short
term
NOAEL
of
25
mg/
kg/
day
for
maternal
effects.
MOEs
for
adult
acute/
short
term
exposures
were
calculated
using
the
target
water
concentration
because
the
acute/
short
term
NOAEL
is
based
upon
the
developmental
effects
which
could
have
occurred
following
one
day
of
exposure.

2.4.2
Exposure
and
Risk
Estimates
The
MOEs
are
summarized
in
Table
26
and
the
detailed
calculations
are
included
in
Appendix
H.
All
of
the
dermal
MOEs
meet
or
exceed
the
target
MOE
of
1000
when
2,4­
D
acid
or
2,4­
D
DMA
are
used
because
these
forms
have
very
low
skin
permeability
coefficients.
The
dermal
MOEs
are
of
concern
when
2,4­
D
BEE
is
used
because
2,4­
D
BEE
has
a
relatively
high
skin
permeability
coefficient.
The
ingestion
MOEs
are
of
concern
for
short
term
children's
exposure
and
are
not
dependent
on
the
form
used.
If
a
lower
target
concentration
of
2
ppm
is
used,
the
MOEs
for
ingestion
rise
to
above
1000,
however,
the
dermal
MOEs
remain
below
1000
for
2,4­
D
BEE
exposures.
40
Table
26
­
MOEs
for
Recreational
Swimmers
in
Water
Bodies
Treated
with
2,4­
D
2,4­
D
Form
Acute
Dermal
MOE
Acute
Ingestion
MOE
Acute
Combined
MOE
Short
Term
Dermal
MOE
Short
Term
Ingestion
MOE
Short
Term
Combined
MOE
2,4­
D
Concentration
=
4
mg/
liter
Adult
­
60
kg
Acid
240000
2500
2500
Short
Term
MOEs
are
the
same
as
acute
MOEs
because
the
same
NOAEL
applies
to
both
acute
and
short
term
exposures.
Adult
DMA
450000
2500
2500
Adult
BEE
350
2500
310
Child
­
22
kg
Acid
550000
2500
2400
200000
920
920
Child
DMA
1000000
2500
2500
380000
920
920
Child
BEE
800
2500
600
300
920
220
2,4­
D
Concentration
=
2
mg/
liter
Adult
­
60
kg
Acid
470000
5000
5000
Short
Term
MOEs
are
the
same
as
acute
MOEs
because
the
same
NOAEL
applies
to
both
acute
and
short
term
exposures.
Adult
DMA
900000
5000
5000
Adult
BEE
700
5000
620
Child
­
22
kg
Acid
1300000
5000
4800
400000
1800
1800
Child
DMA
2400000
5000
5000
760000
1800
1800
Child
BEE
2000
5000
1200
600
1800
440
Note
­
MOEs
in
bold
font
do
not
exceed
the
target
MOE
of
1000
and
are
of
concern
to
the
Agency.

2.5.3
Risk
Characterization
The
probability
that
a
person
would
swim
in
an
area
recently
treated
for
milfoil
is
low
because
milfoil
forms
dense
mats
of
vegetation
on
the
surface
of
the
water
which
makes
swimming
difficult
and
unpleasant.
This
situation
would
occur
prior
to
mid
summer
treatments
when
the
milfoil
has
had
time
to
grow.
Early
season
treatments
are
recommended
to
prevent
milfoil
growth
because
milfoil
is
tolerant
of
cold
water
and
will
grow
fast
in
the
early
spring
when
the
lake
water
is
still
cold.
In
the
case
of
early
season
treatments,
the
cold
water
would
also
reduce
the
time
spent
swimming.

The
acute
MOEs
may
underestimate
risk
in
cases
where
swimming
occurs
immediately
after
subsurface
liquid
applications
before
mixing
has
occurred.
Field
dissipation
studies
reviewed
by
EFED
indicated
that
2,4­
D
concentrations
sometimes
exceeded
the
target
concentration
in
parts
of
the
treated
area
shortly
after
application.
In
the
Minnesota
lake
study
(
MRID
458971­
01),
a
maximum
concentration
of
13.2
ppm
was
measured
at
1
HAT
at
one
of
the
three
sampling
stations
that
were
within
the
treated
area
while
the
average
of
the
three
stations
41
was
4.5
ppm.
By
DAT
1,
the
maximum
and
average
concentrations
had
declined
to
2.7
ppm
and
1.8
ppm.
Many
of
the
states
require
or
recommend
that
a
24
hour
swimming
restriction
be
imposed
following
the
aquatic
application
of
2,4­
D
for
milfoil
control.

The
short
term
MOEs
from
water
ingestion
are
an
upper
bound
estimate
of
risk
because
dissipation
was
not
taken
into
account.
Field
dissipation
studies
reviewed
by
EFED
indicated
that
the
2,4­
D
half
lives
following
the
subsurface
injection
of
2,4­
D
liquid
DMA
to
lakes
and
ponds
(
application
rate
8.4
to
13.6
lbs
ae/
acre
foot)
ranged
from
2.9
to
29.5
days
with
an
average
of
12.9
days
and
a
geometric
mean
of
8.7
days.
The
longest
half
life
occurred
following
the
second
application
to
a
14
acre
pond
in
North
Dakota.
The
half
life
after
the
first
application
was
10.1
days.
The
diagram
for
this
pond
indicates
that
it
had
an
inlet
but
no
outlet
and
the
water
flow
was
not
recorded.
Summary
data
from
these
studies
is
included
in
Table
27.

The
dermal
exposures
from
BEE
might
be
less
than
calculated
because
BEE
degrades
rapidly
to
form
2,4­
D
acid.
This
is
particularly
true
when
the
PH
is
approximately
8.0
as
was
observed
in
a
the
BEE
farm
pond
study
(
MRID
445250­
01)
that
was
reviewed
by
EFED
.
The
majority
of
2,4­
D
detected
after
the
application
of
granular
BEE
was
the
acid
form.
The
maximum
2,4­
D
BEE
concentration
was
71.1
ppb
while
the
maximum
2,4­
D
acid
concentration
was
3370
ppb.
According
literature
cited
by
EFED,
the
average
half
life
of
BEE
is
2.6
hours.

The
BEE
farm
pond
study
indicated
that
the
maximum
2,4­
D
acid
concentration
of
3.4
ppm
was
measured
on
Day
14
in
the
North
Carolina
pond
which
was
characterized
as
being
stagnant
with
opaque
water.
The
maximum
2,4­
D
acid
concentrations
in
the
other
two
ponds
included
in
this
study
were
0.38
ppm
in
the
Minnesota
pond
and
0.15
ppm
in
the
Washington
pond.
These
two
ponds
were
characterized
as
having
some
flow
out
of
the
pond
as
well
as
clear
water.
The
2,4­
D
concentration
in
the
Minnesota
and
Washington
ponds
declined
to
the
LOQ
of
0.002
ppm
in
122
and
30
days,
respectively,
while
the
2,4­
D
concentration
in
the
North
Carolina
pond
was
0.13
ppm
at
189
days
post
application.

The
skin
surface
area
of
21,000
cm2
for
females
as
listed
in
the
SOPs
is
a
95th
percentile
value.
The
median
value
for
this
parameter
is
16,900
cm2.

The
EPA/
ORD
has
recently
completed
the
pilot
phase
of
a
study
that
will
determine
the
ingestion
rate
of
recreational
swimmers.
These
rates
are
being
obtained
by
measuring
urinary
cyanuric
acid
levels
in
swimmers
after
they
swan
in
a
cyanuric
acid
treated
pool.
The
results
for
the
12
adult
swimmers
indicated
that
the
average
ingestion
rate
was
16
ml/
hour
and
the
maximum
rate
was
50
ml/
hour.
The
results
for
the
41
children
indicated
that
the
average
rate
was
37
ml/
hr,
the
70th
percentile
rate
was
50
ml/
hr
and
the
maximum
rate
was
154
ml/
hr.
These
rates
might
be
overestimates
because
the
other
pathways,
such
as
dermal
and
buccal,
were
not
considered.
The
full
study
will
include
600
swimmers.

In
testing
the
use
of
2,4­
D
for
use
in
managing
Eurasian
Watermilfoil
in
Minnesota,
most
treatments
were
done
with
2,4­
D
BEE
(
i.
e.
Aqua­
Kleen(
R)
or
Navigate)
an
application
rate
of
100
lbs
per
acre.
(
Crowell,
1999).
Practical
experience
from
local
applicators
in
Washington
state
has
42
indicated
than
an
application
rate
of
90
to
100
pounds/
acre
may
be
more
effective
than
rates
of
200
pounds
per
acre
due
to
a
change
in
the
plants
physiology
at
higher
rates
(
Washington
State
Dept
of
Ecology,
1998).

Table
27
­
Dissipation
Studies
Following
the
Subsurface
Injection
of
2,4­
D
DMAS
MRID
Location
Water
Body
Type
Size
in
Acres
Acres
Treated
Application
Rate
(
lb
ae)
Treated
Area
Depth
(
feet)
Max
2,4­
D
Concentration
(
ppm)
Half
Life
(
days)

458971­
01
MN
Lake
1700
4.5
10.8
acre/
foot
8.25
13.2
3.2
439083­
02
ND
­
1st
App
Pond
14
14
41.8/
acre
4
to
6
6.1
10.1
ND
­
2nd
App
14
41.8/
acre
4
to
6
4.2
29.5A
439547­
01
NC
­
1st
App
Pond
­
Strea
m
Fed
2.4
2.4
41/
acre
3
2.5B
20.5C
NC
­
2nd
App
2.4
41/
acre
3
3.0
2.9
Avg
GM
Max
12.9
8.7
29.5
A.
This
half
life
is
based
upon
Day
After
Application
(
DAA)
0
to
30.
B.
This
maximum
concentration
occurred
on
DAA
3.
C.
This
half
life
is
based
upon
DAA
3
to
30.

3.0
­
Data
Compensation
Issues
The
TTR
studies
were
submitted
by
the
Broadleaf
Turf
Herbicide
TFR
Task
Force.
This
task
force
includes
many,
but
not
all,
of
the
2,4­
D
registrants.
There
are
data
compensation
issues
regarding
the
use
of
the
TTR
data
to
support
reregistration
of
products
belonging
to
the
2,4­
D
registrants
that
are
not
members
of
the
Broadleaf
Turf
Herbicide
TFR
Task
Force.

Many
of
the
occupational
and
residential
handler
scenarios
were
evaluated
using
unit
exposure
data
that
was
submitted
by
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF).
This
task
force
includes
many,
but
not
all,
of
the
2,4­
D
registrants.
There
are
data
compensation
issues
regarding
the
use
of
the
ORETF
data
to
support
reregistration
of
products
belonging
to
the
2,4­
D
registrants
that
are
not
members
of
the
ORETF.
4.0
­
References
2,4­
D
Smart
Meeting
,
March
6,
2001,
Industry
Task
Force
II
on
2,4­
D
Research
Data
and
the
USDA
Office
of
43
Pest
Management
Policy.

2,4­
D
Master
Label,
March
17,2003,
Industry
Task
Force
II
on
2,4­
D
Research
Data
and
the
USDA
Office
of
Pest
Management
Policy.

Abbott,
et.
al.,
1987
"
Worker
Exposure
to
a
Herbicide
Applied
with
Ground
Sprayers
in
the
United
Kingdom",
AIHA
Journal
48
(
2):
167­
175
Burnside,
Oliver
C.
et
al,
Biologic
and
Economic
Assessment
of
Benefits
from
Use
of
Phenoxy
Herbicides
in
the
United
States,
NAPIAP
Report
Number
1­
PA­
96,
November
1996
Crowell,
Wendy
J.,
November
1999,
"
Minnesota
DNR
Tests
the
Use
of
2,4­
D
in
Managing
Eurasian
Watermilfoil."
Aquatic
Nuisance
Species
Digest,,
Volume
3,
No.
4,
pp
42­
43.

Feldmann
and
Maibach,
"
Percutaneous
Penetration
of
Pesticides
and
Herbicides
in
Man",
Toxicology
and
Applied
Pharmacology
28,
126­
132
(
1974)

Harris
and
Solomon,
1992,
"
Human
Exposure
to
2,4­
D
Following
Controlled
Activities
on
Recently
Sprayed
Turf",
Journal
of
Environmental
Science
and
Health,
B27
(
1),
9­
22
(
1992).

Maroni
et
al./
Chapter
6
­
Phenoxyacetate
Herbicides,
Toxicology
143
(
2000),
77­
83.

USFS,
September
20,
1998,
2,4­
Dichlorophenoxyacetic
acid
Formulation
­
Human
Health
and
Ecological
Risk
Assessment
Final
Report,
Prepared
for
the
USFS
by
Syracuse
Environmental
Research
Associates,
Inc.

U.
S.
EPA,
August,
1997
Exposure
Factors
Handbook
Volume
I
­
General
Factors.
U.
S.
Environmental
Protection
Agency,
Office
of
Research
and
Development,
EPA/
600/
P­
95/
002Fa.

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,
8/
9/
2001,
Quantitative
Usage
Analysis
for
2,4­
D.

U.
S.
EPA,
December
5,
2001
"
A
Pilot
Study
to
Determine
the
Water
Volume
Ingested
by
Recreational
Swimmers",
Paper
Presented
at
the
2001
Annual
Meeting
of
the
Society
of
Risk
Analysis
by
Otis
Evans
et.
al.
of
the
U.
S.
EPA
Office
of
Research
and
Development,
National
Exposure
Research
Laboratory.
44
U.
S.
EPA,
August
23,
2002,
Master
Label
for
the
Reregistration
of
2,4­
Dichlorophenoxyacetic
Acid
Uses
Supported
by
the
2,4­
D
Industry
and
IR­
4
U.
S.
EPA,
March
18,
2003,
Maximum
Application
Rates
for
2,4­
D
Risk
Assessments
U.
S.
EPA,
May
1,
2003,
2,4­
D
Report
of
Hazard
Identification
And
Review
Committee;
Author:
Linda
Taylor,
Ph.
D.,
TXR
NO.
0051866
U.
S.
EPA,
January
14,
2004,
Review
of
2,4­
D
Incident
Reports;
Authors:
Jerome
Blondell,
Ph.
D.
and
Monica
Hawkins,
M.
P.
H.,
DP
Barcode
D297233.

Washington
State
Dept.
of
Ecology,
Feb.
2001,
Herbicide
Risk
Assessment
for
the
Aquatic
Plant
Management
Final
Supplemental
Environmental
Impact
Statement,
Appendix
C,
Volume
3:
2.4­
D
,
Pub.
No.
00­
109­
043
45
5.0
Glossary
of
Terms
Used
in
Occupational/
Residential
Exposure
Assessment
TERM
DEFINITION
Absorbed
Dose
The
amount
of
pesticide
that
is
absorbed
into
the
body.

AE
­
Acid
Equivalent
The
weight
of
2,4­
D
excluding
the
weight
of
the
ester
or
salt
groups
AI
Active
ingredient
DAT
Day
after
treatment
DFR
­
Dislodgeable
Foliar
Residue
The
amount
of
residue
that
can
transfer
from
treated
crop
foliage
to
human
skin.

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,
is
inhaled
or
is
ingested.

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

NOAEL
No
Observed
Adverse
Effect
Level
ORETF
Outdoor
Residential
Exposure
Task
Force
PCO
Pest
Control
Operator
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
appropriate
cartridges
that
has
a
protection
factor
of
10
when
properly
fitted.

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.

PPE
Personal
Protective
Equipment
Short
Term
One
to
thirty
days
TTR
­
Turf
Transferable
Residue
The
amount
of
residue
that
can
transfer
from
treated
turf
to
human
skin.
