UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
PC
Code:
109901
DP
Barcodes:
D297517,
D283708,
D279915,
D279913,
D264522,
D238995,
D239847
Date:
August
30,
2005
MEMORANDUM
SUBJECT:
Ecological
Risk
Assessment
in
Support
of
the
Reregistration
Eligibility
Decision
on
Triadimefon
TO:
John
Pates,
Chemical
Review
Manager
Special
Review
and
Reregistration
Division
FROM:
Michelle
Embry,
Ph.
D.,
Biologist
Jonathan
Angier,
Ph.
D.,
Environmental
Scientist
Environmental
Risk
Branch
II
Environmental
Fate
and
Effects
Division
(
7507C)

THROUGH:
Dana
Spatz,
Risk
Assessment
Process
Leader
APPROVED
BY:
Tom
Bailey,
Ph.
D.,
Branch
Chief
Environmental
Risk
Branch
II
Environmental
Fate
and
Effects
Division
The
Environmental
Fate
and
Effects
Division
(
EFED)
has
completed
its
ecological
risk
assessment
of
triadimefon
in
support
of
the
reregistration
eligibility
decision.
This
is
a
Level
1
national­
scale
ecological
risk
assessment.
The
purpose
of
this
assessment
was
to
determine
whether
current
label
uses
of
triadimefon
provide
a
means
of
exposure
that
could
potentially
result
in
adverse
ecological
effects
(
risk)
to
threatened/
endangered
and
non­
endangered
animals
and
plants.
Assessment
endpoints
include
survival,
reproduction
and
growth
of
terrestrial
and
aquatic
animals
and
plants.
Conclusions
from
this
screening­
level
ecological
risk
assessment
are
in
the
Executive
Summary
of
the
document.
This
assessment
indicates
some
risks
to
aquatic
plants,
freshwater
fish
and
invertebrates,
birds,
and
mammals
associated
with
use
of
triadimefon.
­
2­

The
results
of
this
screening­
level
risk
assessment
suggest
the
potential
for
direct
adverse
chronic
effects
to
birds
and
mammals
at
all
application
rates,
scenarios,
number
of
applications,
and
application
intervals.
Simulations
indicate
that
to
reduce
risk
below
the
chronic
risk
levels
of
concern
for
birds
and
mammals,
the
application
rate
for
a
single
application
would
have
to
be
as
low
as
0.08
lb
ai/
A
and
0.025
lbs
a.
i./
A
for
birds
and
mammals,
respectively.
It
should
be
noted
that
the
endangered
species
assessment
is
preliminary
and
incomplete,
due
to
the
formation
of
the
degradate
1,2,4­
triazole,
which
is
currently
being
addressed
in
a
separate
risk
assessment
by
the
Agency,
as
well
as
the
following
data
gaps.

Major
data
gaps
include:
°
§
123­
2:
Aquatic
vascular
plant
growth
(
triadimefon
and
triadimenol)
°
§
72­
3a:
Estuarine/
Marine
Fish
LC
50
(
triadimefon
and
triadimenol)
°
§
72­
3b:
Estuarine/
Marine
Mollusk
EC
50
(
triadimefon
and
triadimenol)
°
§
72­
3c:
Estuarine/
Marine
Shrimp
EC
50
(
triadimefon
and
triadimenol)
°
§
123­
1a:
Seedling
Emergence
(
triadimefon
and
triadimenol)
°
§
123­
1b:
Vegetative
Vigor
(
triadimefon
and
triadimenol)

°
Information
regarding
the
formation
of
the
degradate
triadimenol
(
rate,
conditions,
and
pathways
of
formation)
