U.
S.
ENVIRONMENTAL
PROTECTION
AGENCY
Washington,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
MEMORANDUM
PC
Code:
028201
Barcode:
D286628
SUBJECT:
Propanil
­
Public
Comments
(
Phase
III)
on
the
Environmental
Fate
and
Effects
Division's
Risk
Assessment.

TO:
Carmen
Rodia,
Chemical
Review
Manager
Reregistration
Branch
III
Special
Review
and
Reregistration
Division
(
7508C)

FROM:
Dana
S.
Spatz,
Senior
Chemist/
Team
Leader
Environmental
Risk
Branch
II
Environmental
Fate
and
Effects
Division
(
7507C)

THRU:
Thomas
A.
Bailey,
Chief
Environmental
Risk
Branch
II
Environmental
Fate
and
Effects
Division
(
7507C)

This
memorandum
serves
as
EFED's
response
to
public
comments
on
our
October
4,
2001
propanil
risk
assessment.
Comments
dated
August
5,
2002
were
received
from
McDermott,
Will
&
Emory
representing
the
Propanil
Task
Force
II.

Concerns
of
potential
risk
to
non­
target
organisms
from
exposure
to
3,4­
dichloroaniline
(
3,4­
DCA),
a
major
degradate
of
propanil,
were
noted
in
the
propanil
risk
assessment.
These
concerns
were
based
on
non­
guideline,
open
literature
information
that
showed
adverse
reproductive
effects
in
invertebrates,
growth
effects
in
fish,
and
toxic
effects
to
the
spleen
and
thymus
of
mammals.
To
address
the
uncertainties
surrounding
the
potential
risk
posed
by
3,4­
DCA,
additional
ecotoxicity
and
environmental
fate
data
were
requested.

In
their
rebuttal
to
the
request
for
additional
data,
the
Propanil
Task
Force
II
states
that
3,4­
DCA
"
may
not
be
a
significant
metabolite
from
the
perspective
of
exposure
based
upon
the
label
uses
of
propanil."
No
additional
information
was
submitted
to
substantiate
this
comment.
On
the
contrary,
as
discussed
in
our
propanil
risk
assessment,
metabolism
studies
demonstrated
that
propanil
degrades
rapidly
and
that
3,4­
DCA
is
the
major
metabolite.
For
example,
in
an
aerobic
soil
metabolism
study,
propanil
degraded
with
a
half­
life
of
12
hours.
The
primary
metabolite
(>
40%)
was
3,4­
DCA,
which
had
a
half
life
of
30
days.
Similarly,
propanil
degraded
rapidly
to
3,4­
DCA
in
the
aquatic
metabolism
studies.
The
significance
of
3,4­
DCA
was
also
evident
in
the
results
of
field
studies
conducted
with
propanil,
USGS
surface
water
monitoring,
and
finally
concentrations
predicted
by
drinking
water
simulation
modeling.
For
Page
2
of
2
example,
as
noted
in
the
risk
assessment,
a
USGS
study
which
analyzed
346
water
samples
collected
in
MS,
MO,
TN,
AR,
and
north
LA
(
mostly
creeks,
bayous,
and
rivers)
from
February
1996
through
February
2001
(
sampling
every
2
weeks
to
monthly),
showed
that
3,4­
DCA
was
detected
with
extremely
high
frequency
(
96.2%)
in
surface
water.

The
Propanil
Task
Force
II
points
out
that
since
3,4­
DCA
is
a
metabolite
of
several
pesticides,
they
anticipate
that
the
ecotoxicity
and
environmental
fate
data
requirements
will
be
applied
to
all
of
these
pesticides.
They
plan
to
work
with
other
groups
as
a
task
force
to
address
the
3,4­
DCA
data
requirements
to
the
extent
necessary
and
applicable
to
propanil.

EFED
agrees
that
the
comprehensive
approach
proposed
by
the
task
force
to
addressing
data
requirements
seems
like
a
worthwhile
effort.
