Document ID: EPA-HQ-OPP-2004-0167-0017
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-05-20T04:00Z

Appendix
J
­
Response
to
Phase
One
ORE
Comments
from
the
2,4­
D
Task
Force
Note:
The
Phase
1
Comments
were
submitted
by
the
Industry
Task
Force
II
on
2,4­
D
Research
Data
in
Laboratory
Study
ID
TFII042104
entitled
"
Error
Only
Response
to
Health
Effects
Division's
Risk
Assessment
for
the
Reregistration
Eligibility
Decision
(
RED)
for
2,4­
Dichlorophenoxyacetic
Acid
(
2,4­
D)".
This
study
was
completed
on
April
21,
2004.
Appendix
J
­
Page
1
Response
to
Phase
1
ORE
Comments
from
the
2,4­
D
Task
Force
Task
Force
Comment
­
Various
Typographical
Errors
The
Task
Force
noted
various
typographical
errors
such
as
the
following:
MCCP
should
be
MCPP­
p
a.
i.
should
be
a.
e.
IPA
should
be
IPE
HED
Response
These
typos
have
been
corrected.

Task
Force
Comment
­
Acute
Toxicity
Values
The
Task
Force
noted
that
some
of
the
acute
toxicity
categories
appeared
to
be
incorrect
and
proposed
corrections
to
Table
2
of
the
ORE
chapter.

HED
Response
The
HED
toxicologist
has
reviewed
acute
toxicity
data
and
concurs
with
the
Task
Force.
Table
2
has
been
revised.

Task
Force
Comment
­
Clarification
of
Orchard
Floors
and
deletion
of
(
Except
CA)
notation.

These
comments
pertain
to
Table
7
which
is
a
listing
of
Application
Rates
for
Agricultural
Crops.

HED
Response
Table
7
has
been
revised
to
reflect
these
comments.

Task
Force
Comment
­
Label
requirements
for
probe
and
pump
mechanical
transfer
systems.

The
Task
Force
contends
that
a
spigot
can
be
used
in
place
of
a
probe
and
pump
as
stated
in
a
Jack
Housenger
Letter
of
January
26,
1995.

HED
Response
HED
concurs
with
this
comment
and
has
updated
the
ORE
Chapter.
Appendix
J
­
Page
2
Task
Force
Comment
­
CARES
is
being
used
instead
of
Lifeline
for
probabilistic
assessment
of
residential
turf
post
application
scenarios.

HED
Response
The
ORE
Chapter
has
been
revised
to
reflect
this
comment.

Task
Force
Comment
­
The
swimming
assessment
for
2,4­
BEE
should
be
conducted
with
the
assumption
that
the
actual
exposure
is
predominantly
to
2,4­
D
acid
rather
than
2,4­
D
BEE.

The
Task
Force
contends
that
the
2,4­
D
BEE
granules
release
their
active
ingredient
so
gradually
that
2,4­
D
acid
is
overwhelmingly
the
detected
residue
in
water.
They
cite
the
low
water
solubility
of
2,4­
D
BEE
(
12.7
ug/
ml,
MRID
42830901)
and
the
rapid
metabolism
to
2,4­
D
acid
(
e.
g.
anaerobic
half
life
14.4
hours,
MRID
42574701)
to
support
the
statement
"
that
there
is
only
minimal
and
transitory
exposure
to
intact
2,4­
D
BEE
in
water."
They
also
cite
aquatic
field
dissipation
studies
(
MRID
44525001)
which
indicated
that
peak
concentrations
of
2,4­
D
BEE
were
much
lower
than
the
corresponding
concentrations
of
2,4­
D
acid.

HED
Response
This
comment
is
outside
the
definition
of
"
error
only"
and
will
not
be
addressed
until
the
next
comment
period.
HED
would
like
to
know,
however,
how
quickly
the
granules
release
the
active
ingredient
as
this
would
impact
the
intensity
and
duration
of
exposure.
HED
has
also
reviewed
MRID
44525001
and
concurs
that
2,4­
D
BEE
concentrations
were
low.
Because
MRID
445250­
01
was
conducted
in
ponds
which
had
a
ph
of
approximately
8.0,
HED
would
like
to
know
what
2,4­
D
BEE
concentrations
would
occur
at
the
lower
ph
values
that
are
more
typical
of
northeastern
lakes.

Task
Force
Comment
­
Correct
half
live
values
in
accordance
with
DER
conclusions
for
the
pond
and
lake
studies
and
recalculation
of
Ave,
GM
and
Max.

The
Task
Force
contends
that
the
half
life
values
listed
in
Table
27
of
the
ORE
chapter
are
incorrect
and
should
be
changed
values
listed
in
the
DERs.
Appendix
J
­
Page
3
HED
Response
The
values
in
Table
27
were
calculated
directly
from
the
study
data.
Some
of
these
values
differ
from
those
cited
by
EFED
because
different
time
periods
were
used
to
calculate
half
lives.
For
example,
HED
calculated
a
half
life
of
27.8
days
for
MRID
439083­
02
(
ND
Pond
App
#
2)
which
is
different
than
the
EFED
calculated
half
life
of
6.5
days
because
HED
used
DAA
0
to
30
data
while
EFED
used
the
DAA
0
to
90
data.
HED
used
the
DAA
0
to
DAA
30
data
because
it
is
more
representative
of
a
short
term
exposure.
HED
has
included
spreadsheets
showing
these
calculations
in
Appendix
I
of
the
revised
ORE
Chapter.

Task
Force
Comment
­
Acres
treated
per
day
during
airblast
spraying
The
Task
Force
contends
that
the
acres
treated
per
day
during
airblast
spraying
is
dependent
upon
the
spray
volume
and
may
less
than
the
HED
assumption
of
40
acres
per
day
if
the
spray
volume
approaches
1000
gallons
per
acre
(
GPA).
They
state
that
labels
specify
minimums
of
100
and
500
GPA,
depending
upon
the
specific
types
of
applications.

HED
Response
The
HED
assumption
of
40
acres
per
day
is
based
upon
a
spray
volume
of
150
GPA
as
listed
in
ExpoSAC
SOP
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture".
Although
this
value
could
be
refined
for
the
500
GPA
application,
this
refinement
is
not
needed
because
the
handler
MOEs
greatly
exceed
the
target
MOE
of
100
due
to
the
very
low
application
rate
of
0.10
lbs
ai/
acre.

Task
Force
Comment
­
Acres
treated
per
day
for
backpack
mixer/
loader
The
Task
Force
contends
that
the
HED
assumption
of
40
acres
per
day
for
the
backpack
mixer/
loader
scenario
is
ten
times
too
high
because
it
is
a
carry
over
from
the
calculation
for
M/
L/
A
which
used
40
gallons
per
day.

HED
Response
The
40
acre
per
day
value
is
based
upon
the
assumption
that
the
backpack
mixer/
loader
would
service
a
crew
of
ten
backpack
applicators.
Each
applicator
would
treat
4
acres
per
day.
The
ORE
Chapter
has
been
revised
to
clarify
this
issue.

Task
Force
Comment
­
The
transfer
coefficient
for
weeding,
scouting,
and
thinning
stem
and
stalk
and
root
vegetables
should
be
a
central
tendency
value.

The
Task
Force
states
that
the
transfer
coefficient
for
low
exposure
(
irrigation,
scouting,
thinning,
weeding
immature
plants)
ranged
from
140­
290
cm2/
hr,
but
the
value
used
in
risk
assessment
was
300
cm2.
All
of
the
other
transfer
coefficients
used
were
typically
either
middle
of
the
range
or
Appendix
J
­
Page
4
were
adjusted
for
the
growth
stage
of
the
plant.
The
reasoning
for
using
a
value
above
the
range
was
not
made
clear.

HED
Response
The
transfer
coefficients
are
selected
from
transfer
coefficient
studies
as
described
in
ExpoSAC
SOP
#
003.1
"
Agricultural
Transfer
Coefficients".
Because
there
are
a
limited
number
of
transfer
coefficient
studies
and
a
wide
variety
of
crops,
it
was
necessary
in
some
cases
to
extrapolate
TC
values
across
crops.
The
transfer
coefficient
of
300
cm2
for
irrigation
and
scouting
of
immature
potato
plants
is
a
high
end
value
from
MRID
428513
­
scouting
cotton
(
range
140
to
290).
The
high
end
value
was
selected
because
of
the
extrapolation
uncertainties.
The
spreadsheets
for
Stem
and
Stalk
vegetables
(
i.
e.
asparagus)
should
not
have
been
included
in
the
ORE
chapter
and
have
been
deleted.

Task
Force
Comment
­
Seven
day
average
water
concentration
values
should
be
used
for
calculating
short
term
swimmer
risks.

The
Task
Force
contends
that
seven
day
average
water
concentration
values
should
be
used
for
calculating
short
term
toddler
swimmer
risks.

HED
Response
The
target
concentration
values
of
2
and
4
ppm
were
used
because
it
was
not
for
possible
to
estimate
7
day
average
values
from
the
submitted
data
The
submitted
data
do
not
cover
the
full
range
of
conditions
that
could
affect
the
seven
day
average
concentrations.
This
issue
will
be
examined
in
more
detail
during
upcoming
comment
periods.

Task
Force
Comment
­
The
most
recent
version
of
the
SWIMODEL
should
be
used.

The
Task
Force
contends
that
most
recent
version
of
the
SWIMODEL
should
be
used
instead
of
the
1996
version
that
was
cited
in
the
ORE
assessment.

HED
Response
The
citation
is
incorrect
and
was
changed
to
reflect
the
fact
that
SWIMODEL
2.0
of
November
20,
2001
was
used.