UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.,
20460
ENVIRONMENTAL
FATE
AND
EFFECTS
DIVISION
OFFICE
OF
PESTICIDE
PROGRAMS
February
4,
2002
PC
Code:
114402
Chemical:
Sodium
Acifluorfen
Related
Chemical:
Lactofen
(
PC
Code
128888)
DP
Barcode:
D278403
TO:
Betty
Shackleford,
PM
53
Christina
Scheltema,
PM
Team
Reviewer
Special
Review
and
Reregistration
Branch
(
7508C)

FROM:
James
Goodyear,
Ph.
D.,
Biologist
Environmental
Risk
Branch
3
Environmental
Fate
and
Effects
Division
(
7507C)

THRU:
Kevin
Costello,
Acting
Branch
Chief
Environmental
Risk
Branch
3
Environmental
Fate
and
Effects
Division
(
7507C)

RE:
Response
to
the
ecological
effects
portion
of
BASF's
"
60­
day
comments"
on
the
draft
RED
on
Sodium
Acifluorfen
posted
to
the
Public
Docket
OPP­
34241.

EFED
has
reviewed
the
ecological
effects
portion
of
BASF's
"
60­
day
comments"
on
the
Environmental
Risk
Assessment
for
the
reregistration
of
the
herbicide
sodium
acifluorfen.
Our
response
is
attached.
2
ECOLOGICAL
EFFECTS
ISSUES
BASF
Comments.
Refutation
of
EFED's
assumptions
of
a
30­
day
foliar
dissipation
half­
life
and
treated
fields
providing
100%
of
the
diet
of
birds
and
mammals.

EPA
states
that
it
has
performed
a
screening
level
assessment
and
a
higher
tier
modeling
assessment
of
the
risk
that
acifluorfen
may
pose
to
birds
and
concludes
that
there
may
be
a
chronic
risk
to
birds
that
eat
short
grass
and
to
insects
after
the
use
of
the
compound
on
peanuts,
soybeans,
or
rice.
BASF
has
submitted
a
study
(
MRID
440911­
01)
entitled
"
Foliar
Dislodgable
Residues
of
Blazer
on
Soybeans"
which
reports
a
half­
life
of
less
than
one
day
on
the
treated
plants
and
no
detectable
residues
after
3­
5
days.
A
more
realistic
assessment
that
includes
a
7­
day
halflife
and
a
smaller
fraction
of
the
diet
obtained
from
the
treated
field
would
result
in
Risk
Quotients
below
EPA's
Level
of
Concern.

EFED
Response:
While
the
results
of
MRID
440911­
01
are
of
interest,
they
are
not
useful
in
developing
a
foliar
dissipation
half­
life.
The
authors
stated
the
following:
".
.
.
in
a
study
of
this
type
it
is
impossible
to
determine
if
the
residues
have
actually
dissipated
or
if
they
have
been
rendered
non­
dislodgable
by
some
other
process
(
e.
g.,
binding).
The
term
dissipation
in
this
report
is
meant
to
express
only
the
reduction
of
dislodgable
residues
with
time."

The
Agency
does
not
possess
BASF's
reference
to
unnamed
preliminary
guidance
by
the
EU
in
which
a
7­
day
half­
life
in
various
media
is
discussed
the
Agency
can
not
address
the
findings.
EFED
will
retain
the
assumption
of
a
30­
day
half­
life,
even
though
the
work
of
Willis
and
McDowell
(
1987)
suggests
a
default
half­
life
of
35
days
appropriate.

Sodium
acifluorfen
will
be
applied
after
the
emergence
of
weeds
as
well
as
the
crop.
They
serve
birds
and
mammals
as
food,
cover,
and
as
a
source
of
invertebrates.
EFED
did
acknowledge
the
uncertainty
associated
with
risk
to
vertebrates
in
the
original
assessment.

In
light
of
some
of
BASF's
comments
a
series
of
ELL
fate
runs
were
made
with
the
lowest
application
rate
(
0.25
lbs
a.
i./
A)
and
half­
lives
of
3­
5
days
based
on
the
dislodgable
residues
as
suggested
by
the
registrant
and
7
days
based
on
the
uncited
results
from
the
EU.
Since
the
chronic
NOAEC
for
birds
is
20
ppm,
even
a
single
application
yields
RQs
of
3
and
1.7
on
short
grass
and
broadleaves/
small
insects
respectively.
These
RQs
exceed
the
chronic
LOC
of
1
ranging
from
2
days
for
(
broadleaves)
or
5
days
for
short
grass
(
with
a
3­
day
halflife
and
48
days
for
short
grass
(
for
the
default
of
30
days).
See
the
attached
spreadsheet
outputs.
In
conclusion,
because
the
chronic
LOC
is
still
exceeded,
no
changes
will
be
made
to
the
original
risk
assessment.
1
Anuran
amphibian
species
have
been
the
focus
of
many
phototoxicity
studies
(
Zage
et
al.,,
1998;
Hatch
and
Burton,
1998;
Walker
et
al.,
1998)
and
protocols
for
standard
toxicity
tests
have
also
been
published
(
ASTM,
1994).
In
nature,
amphibians
may
be
exposed
to
acifluorfen
and
its
degradation
products
through
run­
off
and
spray
drift
or
through
seepage
discharge
of
contaminated
groundwater.
They
are
also
known
to
inhabit
shallow
water
bodies
that
would
be
exposed
to
high
levels
of
solar
radiation.
Therefore,
amphibians
may
exhibit
lightinduced
toxic
effects.

3
BASF
Comments:
Chronic
risk
to
aquatic
animals
in
natural
wavelength
light.
"
The
Agency
states
that
it
is
uncertain
about
the
chronic
risk
of
acifluorfen
to
freshwater
and
estuarine
animals.
However,
based
on
the
data
set
submitted
and
reviewed
for
acifluorfen,
EPA,
in
chapter
3
of
the
preliminary
risk
assessment
(`
Integrated
Environment
Risk
Characterization'),
clearly
states
that
no
chronic
risk
is
anticipated."

EFED
Response.
The
Agency
has
referred
to
a
20­
fold
toxicity
difference
in
LOAEC
between
two
fish
early
life
stage
studies
on
the
rainbow
trout
(
MRID
449632­
01;
D261358.
DER.
WPD))
for
carfentrazone­
ethyl
(
another
phototoxic
herbicide)
as
justification
for
concern
for
the
potential
increased
risk
posed
by
acifluorfen
to
aquatic
organisms
being
exposed
to
natural
sunlight.
BASF
has
questioned
the
risk
potential
of
acifluorfen.
Although
EFED
recognizes
that
if
the
assumed
factor
(
more
accurately
a
14
fold
factor)
would
not
significantly
increase
the
risk
of
aquatic
organisms
exposed
to
acifluorfen,
unless
a
study
is
conducted
there
is
uncertainty
as
to
the
degree
of
potential
risk.

EFED
will
require
that
an
aquatic
phototoxicity
study
be
conducted.
A
fish
early
life
stage
study
or
an
amphibian
study
using
tadpoles
are
possibilities1.
The
choice
of
an
experimental
subject
and
the
protocol
should
be
submitted
for
review
and
agreement
by
both
parties
prior
to
study
initiation.

The
following
are
some
of
the
areas
to
be
addressed:

Endpoints­
Behavioral
observations
should
be
made
in
addition
to
measurements
of
mortality,
growth,
weight,
morphology,
and
appearance.
Ideally,
measurements
of
protoporphyrin
and
heme
concentrations
in
the
blood
and
protox
activity
in
the
liver
of
each
test
organisms
should
be
made.

Light
sources­
Artificial
light
may
be
preferred
to
natural
light
that
will
vary
in
different
regions
and
seasons
as
well
as
with
weather.
If
artificial
light
is
used,
the
light
should
resemble
full,
natural
sunlight
as
closely
as
possible.
No
matter
what
the
light
source,
the
duration
and
intensity
of
UV
and
visible
light
should
be
reported
at
all
wavelengths
(
200­
800
nanometers).

Dark,
light,
and
positive
controls­
As
this
study
is
intended
to
identify
potential
effects
of
light
on
LDPH
toxicity,
an
appropriate
study
protocol
should
include
a
dark,
or
low
light,
4
control
group.
Another
group
that
is
not
exposed
to
chemicals
but
exposed
to
full
light
should
be
included
(
a
full
light
control).
In
addition
to
the
dark
and
light
controls,
a
positive
control
group
using
protoporphyrin
IX
would
be
useful.

Dosing­
A
range
finding
study
should
be
conducted
under
defined
low
light
conditions
to
identify
an
LC50
value
and
lower
dose
levels
expected
to
be
similar
to
controls.
Doses
used
in
the
phototoxicity
study
should
not
be
expected
to
result
in
significant
mortality
in
low
light
controls.
Dissolved
concentrations
of
the
test
chemical
should
be
confirmed
by
an
appropriate
analytical
method.

Exposure
chambers
and
light
filters­
Chambers
should
allow
UV
and
visible
light
to
penetrate.
Any
filters
should
be
cured
under
the
study
light
for
72­
hours
prior
to
study
initiation
to
ensure
consistent
transmittance.

BASF
Comments:
Risk
of
acifluorfen
to
nontarget
terrestrial
plants.
"
The
Agency
states
that
it
is
uncertain
about
the
risk
of
acifluorfen
to
nontarget
terrestrial
plants.
BASF
agrees
.
.
.
BASF
is
willing
to
work
with
the
Agency
to
further
define
the
risk."

EFED
Response:
The
registrant
acknowledges
that
additional
studies
are
needed.
Since
the
original
studies
(
MRID
449632­
01
)
were
performed
with
a
highly
diluted
end
use
product
much
of
the
test
material
may
have
run
off
as
it
was
applied.
Therefore,
using
the
end
use
product,
both
tier
II
seedling
emergence
(
123­
1)
and
vegetative
vigor
(
123­
2)
studies
should
be
repeated.
5
REFERENCES
American
Society
for
Testing
and
Materials.
1994.
Standard
guide
for
conducting
the
frog
embryo
teratogenesis
assay­
Xenopus.
E
1439­
91.
In
Annual
Book
of
ASTM
Standards,
Vol
11.5,
pp.
825­
835.
Philadelphia,
PA.

Hatch,
A.
C.
and
G.
A.
Burton,
Jr.,
1998.
Effects
of
photoinduced
toxicity
of
fluoranthene
on
amphibian
embryos
and
larvae.
Environmental
Toxicology
and
Chemistry
17:
1777­
1785.

Walker,
S.
E.,
D.
H.
Taylor,
and
J.
T.
Oris.
1998.
Behavioral
and
histopathological
effects
of
fluoranthene
on
bullfrog
larvae
(
Rana
catesbeiana).
Environ.
Toxicol.
Chem.
17:
734­
739.

Willis,
G.
H.
and
L.
L.
McDowell.
1987.
Pesticide
persistence
on
foliage.
Reviews
of
Environmental
Contamination
and
Toxicology,
v.
100.
Springer­
Verlag,
New
York.

Zaga,
A.,
E.
E.
Little,
C.
F.
Rabeni,
and
M.
R.
Ellersieck.
1998.
Photoenhanced
toxicity
of
a
carbamate
insecticide
to
early
life
stage
anuran
amphibians.
Environmental
Toxicology
and
Chemistry
17:
2543
­
2553.
