1
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
PC
Code
109702
DP
Barcode
D293413
MEMORANDUM
DATE:
June
9,
2006
SUBJECT:
Addendum
to
the
EFED
RED
Chapter
for
Cypermethrin
TO:
Dirk
Helder,
Chemical
Review
Manager
Veronique
C.
LaCapra,
Chemical
Review
Manager
Margaret
Rice,
Branch
Chief
Reregistration
Branch
2
Special
Review
and
Reregistration
Division
(
7508P)

FROM:
Michael
Hoffmann,
Biologist
Miachel
Rexrode,
Aquatic
Biologist,
Senior
Scientist
Ronald
Parker,
Senior
Environmental
Engineer
José
Luis
Meléndez,
Chemist
Environmental
Risk
Branch
V
Environmental
Fate
and
Effects
Division
(
7507P)

THROUGH:
Karen
Whitby,
Acting
Chief
Environmental
Risk
Branch
V
Environmental
Fate
and
Effects
Division
(
7507P)

The
purpose
of
this
Addendum
to
the
EFED
RED
Chapter
for
Cypermethrin
is
to
address
a
number
of
issues
that
were
raised
by
the
Special
Review
and
Reregistration
Division
(
SRRD)
and
other
parties
regarding
previous
versions
of
the
chapter.
This
addendum
contains
a
list
of
issues
and
EFED's
corresponding
responses,
as
well
as
additional
analyses
on
the
effects
of
buffers
on
spray
drift,
a
revised
terrestrial
risk
assessment,
and
additional
details
on
ecological
incidents
reported
for
cypermethrin.

Issue
#
1:
There
has
been
inconsistent
use
of
various
input
parameters
for
determining
exposure
and
risk
to
terrestrial
animals
in
the
original
risk
assessment
and
the
subsequent
revisions.
Corrected
mammalian
and
avian
acute
and
chronic
RQs
are
needed,
along
with
a
clear
explanation
of
which
input
values
were
incorrect
in
the
original
assessment,
and
what
the
correct
T­
REX
input
values
are.

Response
to
Issue
#
1:
Mammalian
and
avian
acute
and
chronic
RQs
have
been
recalculated,
and
a
clear
explanation
of
which
input
values
were
used
to
derive
them
has
been
included
below
in
Table
1
of
the
revised
terrestrial
risk
assessment.
The
maximum
number
of
applications
per
year,
the
minimum
application
intervals,
and
the
maximum
application
rates
for
each
crop
were
derived
from
the
product
labels
and
have
been
used
as
stated.
The
foliar
half­
life
of
16.1
days
that
was
used
in
this
revision
was
based
on
data
for
2
cypermethrin
in
Willis
and
McDowell
(
1987).
This
half­
life
is
different
than
was
used
previously
in
all
versions
of
the
cypermethrin
risk
assessment.
Additional
discussion
regarding
this
half­
life
is
provided
below
in
the
revised
terrestrial
risk
assessment.

Issue
#
2:
No
effects
were
observed
in
the
available
chronic
avian
studies
with
cypermethrin,
but
the
highest
dose
tested
was
only
50
ppm.
In
a
previous
revision,
the
permethrin
NOAEC
(
identified
as
150
ppm)
was
used
to
determine
chronic
risk
to
birds
instead
of
the
NOAEC
value
of
>
50
ppm
used
in
the
original
risk
assessment,
but
with
no
supporting
explanation.
In
addition,
the
permethrin
NOAEC
is
listed
as
125
ppm
on
p.
67
of
the
original
cypermethrin
risk
assessment,
and
has
been
changed
to
500
ppm
in
the
most
recent
EFED
addendum
for
permethrin.
Therefore,
the
150
ppm
NOAEC
value
used
for
cypermethrin
seems
to
be
a
mistake.
The
NOAEC
that
is
most
appropriate
for
determining
chronic
avian
risk
should
be
clearly
identified
and
explained.

Response
to
Issue
#
2:
Neither
the
125
ppm
nor
the
150
ppm
values
should
be
reported
as
the 
NOAEC
value
for
the
permethrin
avian
reproduction
study
(
MRID
42322902).
The
150
ppm
treatment
was
not
actually
a
concentration
tested
in
the
available
studies,
and
although
the
125
ppm
was
a
true
test
level,
it
represents
an
incorrect
NOAEC
because
no
significant
effects
were
observed
at
any
test
level
up
to
and
including
the
highest
test
concentration
of
500
ppm.

Instead,
EFED
has
recalculated
risk
quotients
for
birds
below
based
on
the
correct
NOAEC
of
500
ppm
(
LOAEC
>
500
ppm)
from
the
two
avian
reproduction
studies
for
permethrin
(
MRID
42322902
and
MRID
42322901).
The
available
avian
reproduction
studies
for
cypermethrin
(
MRID
90072
and
MRID
90074)
showed
no
adverse
treatment­
related
effects
to
mallards
or
bobwhite
quail.
However,
they
were
only
conducted
at
maximum
concentrations
of
50
ppm.
Although
no
effects
were
seen
in
either
study,
if
the
nondefinitive
NOAEC
(>
50
ppm)
value
from
the
avian
reproduction
studies
with
cypermethrin
was
used,
uncertainty
would
be
high
because
risk
to
avian
species
could
not
be
precluded.
Subsequently,
the
NOAEC
value
for
permethrin
(
NOAEC
=
500
ppm)
was
used
to
demonstrate
low
risk
to
birds
resulting
from
cypermethrin
use.
Permethrin
data
are
considered
to
be
suitable
surrogate
data
for
cypermethrin
because
both
chemicals
are
pyrethroids,
they
are
structurally­
similar
compounds
with
similar
modes
of
action,
and
both
are
expected
to
be
of
low
chronic
toxicity
to
birds.

The
use
of
the
NOAEC
of
500
ppm
did
not
result
in
any
chronic
LOC
exceedances
for
birds
(
described
in
the
revised
terrestrial
risk
assessment
below).
This
is
in
contrast
to
the
original
assessment,
which
found
that
avian
species
were
at
chronic
risk
when
estimates
were
based
on
a
NOAEC
of
>
50
ppm.

Issue
#
3:
The
original
EFED
assessment
lists
different
NOAECs
(
and
NOAELs)
for
determining
chronic
mammalian
risk
in
different
parts
of
the
assessment
and
it
is
not
clear
as
to
which
of
the
reported
values
is
correct.
In
the
original
assessment,
chronic
risk
to
mammals
was
eventually
determined
using
a
NOAEL
of
7.5
mg/
kg/
day
and
a
NOAEC
of
150
ppm
(
MRIDs
00112912,
42068504,
9202704).
While
revisions
to
the
original
assessment
employed
these
values
to
determine
chronic
risk
to
mammals
for
most
crop
scenarios,
risk
to
mammals
for
the
cotton
crop
scenario
was
determined
using
a
NOAEL
of
5
mg/
kg/
day
and
a
NOAEC
of
150
ppm.
The
correct
NOAEL
(
and
NOAEC)
for
assessing
chronic
mammalian
risk
for
all
crops
should
be
identified.

Response
to
Issue
#
3:
The
NOAEC
value
of
150
ppm
(
LOAEC
=
750
ppm,
NOAEL
=
7.5
mg/
kg/
day,
and
LOAEL
=
50/
37.5
mg/
kg/
day)
from
a
3­
generation
reproduction
study
(
MRIDs
00112912,
42068504,
and
92027040)
was
based
on
decreased
body
weight
gain
in
parents
(
typically
 
10%
from
controls
for
males
and
females)
and
decreased
mean
litter
weight
gain
during
lactation
( 
12%
to
21%
for
F1B
and
 
12%
to
17%
for
F1B
females
for
days
10
to
28).
The
NOAEC
value
of
100
ppm
(
LOAEC
=
500
ppm,
NOAEL
=
5
mg/
kg/
day,
and
LOAEL
=
25
mg/
kg/
day)
from
another
3­
generation
reproduction
study
(
MRID
00090040)
was
based
on
decreased
body
weight
gain
in
parents
( 
3%
and
 
7%
from
controls
for
males
and
females,
respectively,
at
the
500
ppm
level;
p 
0.05)
and
pups
( 
4.0%
from
controls
at
the
500
ppm
level;
p 
0.01).
In
3
this
addendum,
the
NOAEC
value
of
100
ppm
(
NOAEL
=
5
mg/
kg/
day)
was
used
to
determine
chronic
risk
to
mammals
for
all
crop
scenarios
because
it
is
the
most
conservative
(
lowest),
accurate
value
available
for
cypermethrin.

"
Issue
#
4:
A
thorough
description
of
the
ecological
incidents
for
cypermethrin
is
needed.

Response
to
Issue
#
4:
The
incidents
that
were
attributed
to
cypermethrin
exposure
are
very
limited
in
information.
However,
five
incidents
involving
terrestrial
organisms
(
birds,
goats,
dogs)
were
noted.
The
incident
involving
birds
(
5000
sparrows)
may
be
attributed
to
birds
eating
insects
that
had
been
killed
from
cypermethrin
use
the
previous
night
on
an
eggplant
crop
(
I011348­
001);
however,
a
number
of
other
chemicals
could
also
be
responsible.
Incidents
involving
fish
and
other
aquatic
organisms
were
about
double
the
incidents
involving
terrestrial
organisms.
Although
in
about
half
of
these
aquatic
incidents
the
source
of
cypermethrin
was
not
reported
(
I007107­
003,
I006971­
001,
I010444­
004,
I013857­
011),
several
fish
kills
were
attributed
to
termidicide
use
of
cypermethrin
(
I009966­
002,
I001031­
001,
I000011­
001,
I015094­
001).

Additional
details
on
the
reported
terrestrial
and
aquatic
incidents
for
cypermethrin
are
detailed
below
in
Incident
Tables
1
and
2,
respectively.

Issue
#
5:
EFED
should
provide
a
complete
explanation
of
the
data
requirements
and
should
thoroughly
address
any
relevant
changes
that
have
been
made
to
the
original
risk
assessment.

Response
to
Issue
#
5:
In
the
original
risk
assessment
for
cypermethrin,
the
following
data
gaps
were
identified:

(
1)
71­
4
(
a):
Avian
Reproduction,
Quail
(
2)
72­
4
(
b):
Aquatic
Invertebrate
Life­
Cycle,
Freshwater
(
3)
OPPTS
Harmonized
Test
Guideline
850.1735:
Whole
Sediment
Acute
Toxicity
Testing
with
Freshwater
Invertebrates
(
Chironomus
tentans)
(
4)
EPA/
600/
R­
99/
064:
Chronic
Freshwater
Sediment
Testing­
A
65­
day
Test
with
Chironomus
tentans
(
5)
EPA/
600/
R01/
020:
Chronic
Estuarine/
Marine
Sediment
Testing­
A
28­
day
Test
with
Leptocheirus
plumulosus
However,
since
the
original
assessment
was
written,
the
OPPTS
Harmonized
Test
Guideline
850.1735,
EPA/
600/
R­
99/
064,
and
EPA/
600/
R01/
020
studies
have
been
submitted
to
the
Agency
by
the
Pyrethroid
Working
Group,
but
have
not
yet
been
reviewed
or
incorporated
into
this
risk
assessment.
In
addition,
the
NOAEC
values
from
the
available
avian
reproduction
studies
for
permethrin
have
been
used
in
lieu
of
definitive
values
for
cypermethrin,
and
are
considered
appropriate
for
precluding
significant
chronic
risk
to
avian
species
(
see
discussion
in
the
revised
terrestrial
risk
assessment
below).
Therefore,
at
this
time,
only
72­
4(
b):
Aquatic
Invertebrate
Life­
Cycle,
Freshwater,
is
still
identified
as
a
data
gap.

Issue
#
6:
A
revised
spray
drift
discussion
is
needed.

Response
to
Issue
#
6:
A
revised
discussion
is
included
below
in
the
section
entitled,
"
Effect
of
Buffers
on
Spray
Drift."

Issue
#
7:
It
appears
that
the
EFED
may
have
overlooked
the
acute
toxicity
study
with
Daphnia
magna
(
MRID
43293501;
Wheat
and
Evans,
1994)
or
transcribed
its
results
incorrectly
in
the
RED.
The
48­
hr
EC50
value
of
161.5
pptr
(
161.5
ng
ai/
L)
from
the
study
(
not
µ
g
a.
i./
L,
as
it
was
reported
in
the
Chapter)
appears
to
be
the
most
sensitive
endpoint
available
for
freshwater
invertebrates,
yet
it
was
not
used
to
calculate
risk
for
this
taxonomic
group.
4
Response
to
Issue
#
7:
MRID
43293501
was
not
overlooked
in
the
document
and
the
most
sensitive
endpoint
was
used
to
calculate
risk
to
freshwater
invertebrates;
however,
MRID
43293501
was
misclassified
in
the
RED
and
the
units
for
the
endpoint
were
reported
incorrectly.
The
individual
data
evaluation
record
(
DER)
for
the
study
indicates
that
the
study
was
not
scientifically
sound
because
there
was
significant
contamination
of
the
controls.
The
study
report
itself
also
states
that
the
measured
"
residues
from
the
cypermethrin
exposure 
did
not
follow
a
serial
dilution
pattern"
and
that
the
"
analysis
of
test
samples
failed
to
yield
useful
results."
Therefore,
the
study
should
have
been
classified
as
Invalid
and
should
not
have
been
discussed
in
the
RED.

Issue
#
8:
In
the
analysis
of
effects
on
estuarine/
marine
invertebrates,
toxicity
data
from
benthic
and
open
water
species
were
combined.
Yet
in
the
analysis
of
effects
on
freshwater
invertebrates,
the
Science
Chapter
separated
toxicity
data
for
benthic
species
from
data
for
Daphnia
magna,
and
used
Daphnia
magna
as
a
surrogate
for
all
freshwater
water
column
invertebrates.
Data
from
water­
only
studies
with
freshwater
invertebrate
species
considered
to
be
benthic
were
not
used
in
the
effects
characterization
for
the
water
column.
In
addition,
not
all
of
the
test
organisms
listed
as
benthic
in
Table
E­
4
are
actually
sediment
dwellers;
for
example,
adult
whirligigs
(
Gyrinus),
backswimmers
(
Notonecta),
water
boatmen
(
Corixa),
and
water
mites
(
Piona).
The
segregation
of
benthic
from
water
column
species
was
not
discussed,
and
no
justification
was
presented.
By
segregating
data
from
benthic
and
water
column
species
this
assessment
deviates
from
EPA's
stated
practice
of
basing
screening­
level
RQs
on
the
most
sensitive
species
in
each
category
of
organisms.
Daphnia
magna
is
in
fact
the
least
sensitive
of
the
five
freshwater
crustacean
species
for
which
water­
only
toxicity
data
are
presented
in
Appendix
E.
As
has
been
found
for
other
synthetic
pyrethroids,
amphipods
(
Gammarus
and
Hyalella)
are
substantially
more
sensitive
than
Daphnia
magna.
If
data
from
all
water­
only
toxicity
tests
with
freshwater
invertebrates
were
used
to
characterize
effects
on
water
column
species,
the
Toxicity
Reference
Value
would
have
been
0.0036
µ
g/
L
(
Hyalella
azteca,
96­
h
LC50)
rather
than
0.42
µ
g/
L
(
Daphnia
magna,
48­
h
EC50).
RQs
for
freshwater
invertebrates
would
have
been
approximately
100
times
greater
than
those
calculated
in
the
Science
Chapter.
Use
of
Daphnia
magna
data
to
represent
all
water
column
invertebrates
reduces
the
apparent
risk
of
cypermethrin.

Response
to
Issue
#
8:
The
Agency
acknowledges
that
some
of
the
species
listed
in
the
table
referring
to
Freshwater
Benthic
Invertebrates
are
not
benthic
(
e.
g.,
adult
whirligigs
(
Gyrinus),
backswimmers
(
Notonecta),
water
boatmen
(
Corixa),
and
water
mites
(
Piona)).
EFED
also
agrees
that
the
data
for
aquatic
invertebrates
would
have
been
most
transparently
separated
based
on
water
column
toxicity
(
studies
with
water­
only
systems)
data
and
sediment
toxicity
(
studies
with
water­
sediment
systems)
data.

The
two
most
important
considerations
when
selecting
toxicity
data
to
characterize
risk
to
a
specific
taxonomic
group
are
whether
the
data
are
the
most
sensitive
available
and
whether
the
exposure
scenario
under
which
the
endpoints
were
derived
are
appropriate
and
representative
of
that
group
of
organisms.
The
RED
explicitly
states
in
Appendix
E:

"
In
the
water
system
studies,
organisms
were
exposed
only
to
cypermethrin
in
overlying
water;
there
was
no
sediment
in
the
test
chamber.
Thus,
while
data
from
these
studies
provide
information
regarding
the
sensitivity
of
benthic
organisms
to
cypermethrin
in
surface
water,
no
data
from
these
studies
regarding
exposure
to
cypermethrin
in
sediment
are
available.
Therefore,
data
are
insufficient
for
use
in
quantifying
risks
to
benthic
organisms,"
and
"
studies
using
the
water­
sediment
system
more
accurately
depict
the
environmental
exposure
of
benthic
organisms
than
the
water
system
studies."

Therefore,
only
those
studies
that
exposed
sediment
dwellers
to
cypermethrin
in
a
water­
sediment
system
were
considered
appropriate
for
determining
risk
to
benthic
organisms.
The
only
two
studies
that
met
these
criteria
were
MRID
44074402
and
MRID
44074406.

EFED
agrees
that
it
may
be
appropriate
to
use
the
study
with
Hyallella
(
MRID
44423501)
to
characterize
5
risk
to
freshwater
water
column
dwelling
species
because
this
species
can
spend
time
in
both
the
water
column
and
benthos
and
because
the
study
was
conducted
in
a
water­
only
system.
However,
the
EFED
reviewer
exercised
best
professional
judgment
and
chose
the
Daphnia
measurement
endpoint
because
the
use
of
this
endpoint
allows
for
a
comparative
analysis
of
toxicity
to
most
other
chemicals.
Although
the
96­
hour
LC50
value
of
0.0036
µ
g
a.
i./
L
for
Hyalella
azteca
(
based
on
a
water­
only
system)
may
be
appropriate
for
determining
risk
to
all
freshwater
water
column
dwelling
organisms,
freshwater
invertebrate
acute
RQs
still
exceeded
all
acute
LOCs
(
RQ
range=
0.4
­
4.8)
when
based
on
the
48­
h
EC50
value
of
0.42
µ
g
a.
i./
L
for
Daphnia
magna.
If
based
on
the
endpoint
for
Hyalella,
acute
RQs
would
be
approximately
100
times
higher
and
range
from
49.4
to
558.3.

In
addition,
chronic
RQs
for
freshwater
invertebrates
would
also
increase
if
the
Hyalella
measurement
endpoint
is
used.
Because
no
chronic
data
were
available
for
freshwater
invertebrates,
a
surrogate
NOAEC
toxicity
value
was
derived
to
calculate
chronic
RQs
for
this
taxonomic
group.
Previously,
the
chronic
NOAEC
estimated
for
freshwater
invertebrates
was
based
on
the
acute­
to­
chronic
ratio
method,
determined
by
using
the
acute
Daphnia
measurement
endpoint
and
the
following
mathematical
relationship:

Estuarine/
marine
invertebrate
LC50
(
0.00475
µ
g
a.
i./
L)
/
Estuarine/
marine
invertebrate
NOAEC
(
0.000781
µ
g
a.
i./
L)
=
Freshwater
invertebrate
LC50
(
0.42
µ
g
a.
i./
L)/
X
(
estimated
value
for
Freshwater
invertebrate
NOAEC),
where
X
=
0.069
µ
g
a.
i./
L.

Based
on
this
derived
NOAEC
for
freshwater
invertebrates,
chronic
RQs
exceeded
chronic
LOCs
and
ranged
from
0.5
to
2.8.
However,
because
a
more
sensitive
endpoint
has
now
been
identified,
a
chronic
NOAEC
can
be
estimated
for
freshwater
invertebrates
using
the
acute
Hyalella
measurement
endpoint
and
the
following
mathematical
relationship:

Estuarine/
marine
invertebrate
LC50
(
0.00475
µ
g
a.
i./
L)
/
Estuarine/
marine
invertebrate
NOAEC
(
0.000781
µ
g
a.
i./
L)
=
Freshwater
invertebrate
LC50
(
0.0036
µ
g
a.
i./
L)/
X
(
estimated
value
for
Freshwater
invertebrate
NOAEC),
where
X
=
0.00059
µ
g
a.
i./
L.

Based
on
this
newly
estimated
NOAEC
value,
chronic
RQs
for
freshwater
invertebrates
would
be
approximately
100
times
higher
and
range
from
57.6
to
325.4.
Therefore,
while
use
of
the
Daphnia
EC50
value
may
foster
a
comparative
analysis,
its
use
may
also
result
in
RQs
that
underestimate
acute
and
chronic
risk
to
freshwater
water
column
dwelling
invertebrates.

Issue
#
9:
The
analysis
described
above
based
on
Daphnia
magna
leads
EFED
to
the
erroneous
conclusion
in
the
Aquatic
Effects
Characterization
Section
that
estuarine/
marine
invertebrates
are
substantially
more
sensitive
to
cypermethrin
than
freshwater
invertebrates.
The
EFED
states
that
for
estuarine/
marine
invertebrates,
the
lowest
LC50
value
reported
is
0.00475
µ
g
a.
i./
L,
which
is
100
times
lower
than
reported
for
other
aquatic
animals.
However,
it
appears
that
data
for
freshwater
amphipods
was
ignored
(
e.
g.
Hyalella
azteca
and
Gammarus
species),
which
are
approximately
100
times
more
sensitive
than
Daphnia
magna.
Moreover,
the
relative
sensitivities
would
be
better
represented
by
means,
medians
or
Entire
Sensitivity
Distributions.
The
EFED
Science
Chapter
also
says
that
estuarine/
marine
invertebrates
are
expected
to
be
the
taxonomic
group
at
greatest
risk.
However,
based
on
studies
not
yet
published,
freshwater
and
marine
invertebrates
are
approximately
equal
in
their
sensitivity
to
cypermethrin.

Response
to
Issue
#
9:
The
EFED
does
not
use
means,
medians,
or
Entire
Sensitivity
Distributions
in
screening­
level
risk
assessments,
but
rather,
bases
risk
conclusions
on
the
most
sensitive
data
available.
The
EFED
acknowledges
that
it
may
be
considered
appropriate
to
use
the
study
with
Hyallella
(
MRID
44423501)
to
characterize
risk
to
freshwater
water
column
dwelling
species
(
Please
refer
to
the
Agency's
Response
to
Issue
#
8),
and
that
based
on
such
an
analysis,
the
sensitivity
of
and
risk
to
estuarine/
marine
invertebrates
is
on
par
with
freshwater
invertebrates.
However,
while
the
EFED
cannot
comment
on
the
unpublished
data
mentioned
above,
the
increased
sensitivity
of
estuarine/
marine
invertebrates
does
appear
to
6
be
consistent
among
other
pyrethroids
and
may
be
correlated
with
osmoregulation.

Issue
#
10:
The
following
is
stated
in
the
Science
Chapter:

"
For
two
studies,
the
acute
NOAEC
value
for
sub­
lethal
effects
was
several
orders
of
magnitude
lower
than
the
LC50
value;
in
rainbow
trout,
the
acute
NOAEC
and
LC50
values
were
0.00068
µ
g
a.
i./
L
and
0.8
µ
g
a.
i./
L,
respectively
(
Acc.
No.
241598),
and
in
bluegill
sunfish,
the
acute
NOAEC
and
LC50
values
were
<
0.0022
µ
g
a.
i./
L
and
2.2
µ
g
a.
i./
L,
respectively
(
Acc.
No.
241598).
Thus,
sub­
lethal
effects
can
occur
at
exposure
levels
far
below
the
concentrations
that
cause
lethality."

However,
the
NOAEC
values
cited
for
Bluegill
sunfish
and
Rainbow
trout
are
incorrect.
The
NOAEC
units
should
be
mg/
L
instead
of
µ
g/
L.
Therefore,
the
LC50
=
0.8
µ
g
a.
i./
L
and
the
NOAEC
=
0.68
µ
g/
L
for
rainbow
trout,
while
the
LC50
=
2.2
µ
g
a.
i./
L
and
the
NOAEC<
2.2
µ
g/
L
for
bluegill
sunfish.

Response
to
Issue
#
10:
The
EFED
acknowledges
that
the
LC50
and
the
NOAEC
values
for
rainbow
trout
are
0.8
and
0.68
µ
g
a.
i./
L,
respectively,
while
the
LC50
and
the
NOAEC
values
for
bluegill
sunfish
are
2.2
and
<
2
µ
g
a.
i./
L,
respectively.
Therefore,
while
sub­
lethal
effects
can
still
occur
at
exposure
levels
below
the
concentrations
that
cause
lethality,
the
magnitude
of
the
difference
between
these
values
may
not
be
as
large
as
originally
anticipated.
7
Revised
Terrestrial
Animal
Risk
Assessment
I.
Introduction
The
terrestrial
risk
assessment
for
cypermethrin
was
revised
according
to
the
comments
above.
Based
on
the
comments,
risk
quotients
for
terrestrial
organisms
were
recalculated
using
T­
REX
v1.2.3
and
the
input
values
and
toxicity
reference
values
described
below
in
Tables
1
and
2,
respectively.
Cotton,
pecan,
canola,
and
lettuce
crop
scenarios
were
all
considered
in
this
addendum
in
order
to
be
consistent
with
the
original
risk
assessment
and
because
they
represent
over
90%
of
cypermethrin's
agricultural
use.
However,
risk
quotients
(
RQs)
have
now
been
calculated
based
on
different
NOAEC/
NOAEL
values
for
birds
and
mammals,
and
different
foliar
dissipation
half­
lives
than
were
used
in
the
original
risk
assessment.

II.
Terrestrial
Exposure
Analysis
The
EFED
terrestrial
exposure
model
T­
REX
(
T­
REX,
Version
1.2.3,
dated
August
8,
2005)
is
used
to
estimate
exposure
and
risk
to
avian
and
mammalian
species.
Input
values
for
avian
and
mammalian
toxicity
as
well
as
chemical
application
and
foliar
dissipation
half­
life
data
are
required
to
run
the
model.
The
model
provides
estimates
of
exposure
concentrations
and
risk
quotients
(
RQs).
Specifically,
the
model
provides
estimates
of
concentrations
(
upper­
bound
and
mean)
of
chemical
residues
on
the
surface
of
different
types
of
foliage
and
insects
that
may
be
dietary
sources
of
exposure
to
avian,
mammalian,
reptilian,
or
terrestrialphase
amphibian
receptors.
The
surface
residue
concentration
(
ppm)
is
estimated
by
multiplying
the
application
rate
(
pounds
active
ingredient
per
acre)
by
a
value
specific
to
each
food
item.

For
multiple
applications,
the
EEC
is
determined
by
adding
the
mass
on
the
surface
immediately
following
the
application
to
the
mass
of
the
chemical
still
present
on
the
surfaces
on
the
day
of
application
(
determined
based
on
first
order
kinetics
using
the
foliar
half­
life
as
the
rate
constant).
Input
values
used
for
estimating
avian
and
mammalian
exposure
risks
to
cypermethrin
are
summarized
in
Table
1.
The
maximum
number
of
applications
per
year,
the
minimum
application
intervals,
and
the
maximum
application
rates
for
each
crop
were
derived
from
the
product
labels,
whereas
the
foliar
half­
life
of
16.1
days
was
based
on
data
for
cypermethrin
in
Willis
and
McDowell
(
1987).

The
foliar
half­
life
of
16.1
days
represents
the
90%
upper
confidence
limit
of
the
mean
half­
life
for
all
crops
that
had
half­
life
estimates
based
on
total
residues
(
internal
plus
dislodgeable
residues).
Data
on
all
available
crops
(
i.
e.,
cotton
and
beans)
were
considered
because
T­
REX
is
used
to
calculate
terrestrial
exposure
concentration
estimates
on
all
plant
surfaces
following
pesticide
application,
and
not
just
concentration
estimates
on
a
particular
crop.
However,
half­
lives
based
on
dislodgeable
residues
alone
were
not
considered
for
cypermethrin
because
the
compound
has
a
high
log
kow
(
6.4)
and
is
expected
to
bind
strongly
to
plants.
Therefore,
half­
lives
based
on
total
residues
(
i.
e.,
half­
lives
of
7.9
and
4.8
for
cotton
and
beans,
respectively)
will
likely
provide
more
realistic
estimates,
whereas
half­
lives
based
on
dislodgeable
residues
alone
will
likely
underestimate
exposure
concentrations.

By
comparing
estimated
concentrations
to
acute
and
chronic
toxicity
reference
values,
acute
and
chronic
RQs
are
calculated.
The
EECs
on
food
items
may
be
compared
directly
with
dietary
toxicity
data
or
converted
to
an
oral
dose,
as
is
done
for
small
mammals.
For
mammals,
the
residue
concentration
is
converted
to
daily
oral
dose
based
on
the
fraction
of
body
weight
consumed
daily
as
estimated
through
mammalian
allometric
relationships.
The
screening­
level
risk
assessment
for
cypermethrin
uses
upper­
bound
predicted
residues
as
the
measure
of
exposure.
Summaries
of
the
predicted
residues
of
cypermethrin
that
may
be
expected
to
occur
on
selected
avian
or
mammalian
food
items
immediately
following
application
for
the
maximum
use
scenarios
are
presented
in
Table
2.
8
Table
1.
Input
parameters
for
cypermethrin
used
in
T­
REX
(
v1.2.3).

Crop
Application
rate
(
lbs
a.
i./
A)
Foliar
half­
life
a
(
days)
Frequency
of
application
(
days)
Maximum
applications
per
year
Cotton
0.1
16.1
3
6
Lettuce
0.1
16.1
7
6
Canola
0.1
16.1
7
4
Pecans
0.1
16.1
5
6
a
This
half­
life
represents
the
90%
upper
confidence
limit
of
the
mean
half­
life
for
all
crops
that
had
half­
life
estimates
based
on
total
residues
(
internal
plus
dislodgeable
residues)
in
Willis
and
McDowell
(
1987).

Table
2.
Upper­
bound
foliar
estimated
environmental
concentrations
(
EECs;
in
ppm)
for
cypermethrin
applications
to
various
crops.
a
Crop
Foliage
type
Cotton
Lettuce
Canola
Pecans
Short
grass
107
77
65
90
Tall
grass
49
35
30
41
Broadleaf/
forage
plants
&
small
insects
60
43
36
51
Fruits/
pods/
seeds/
large
insects
7
5
4
6
a
EEC
equivalent
dose
=
Upper­
bound
Kenega
value
*
(%
BW
consumed/
100).
%
BW
consumed
=
114%,
65%,
and
29%
for
small,
medium,
and
large
birds,
respectively.

III.
Risk
Characterization
A.
Terrestrial
Risk
Estimation
­
Integration
of
Exposure
and
Effects
Data
Results
of
the
exposure
and
toxicity
effects
data
are
used
to
evaluate
the
likelihood
of
adverse
ecological
effects
on
non­
target
species.
For
the
assessment
of
cypermethrin
risks,
the
risk
quotient
(
RQ)
method
is
used
to
compare
exposure
and
measured
toxicity
values
(
refer
to
Appendix
F).
Estimated
environmental
concentrations
(
EECs)
are
divided
by
the
most
sensitive
acute
and
chronic
toxicity
values
(
Table
3;
refer
to
the
EFED
RED
Chapter
for
Cypermethrin
for
details
on
the
studies
from
which
these
were
derived).
The
RQs
are
then
compared
to
the
Agency's
levels
of
concern
(
LOCs).
These
LOCs,
summarized
in
Appendix
F,
are
the
Agency's
interpretive
policy
and
are
used
to
provide
some
perspective
on
estimated
potential
risk
to
non­
target
organisms
and
the
need
to
consider
regulatory
action.
These
criteria
are
used
to
indicate
when
a
pesticide's
use
as
directed
on
the
label
has
the
potential
to
cause
adverse
effects
on
non­
target
organisms
which
may
warrant
risk
mitigation.

The
EFED
terrestrial
exposure
model
T­
REX
(
T­
REX,
Version
1.2.3,
dated
August
8,
2005)
was
used
to
estimate
exposure
and
risks
in
conservative
scenarios
to
avian
species
for
four
forage
food
types
and
to
mammalian
species
for
five
forage
food
types
for
spray
applications
of
cypermethrin
as
described
in
the
Exposure
Characterization.
For
this
risk
assessment,
terrestrial
EECs
as
a
result
of
spray
applications
were
estimated
using
the
maximum
proposed
application
rate,
the
maximum
number
of
applications,
and
the
9
minimum
application
interval
for
cypermethrin
spray
applications
for
four
representative
crop
scenarios.
Risk
quotients
were
calculated
using
upper­
bound
EECs.
For
birds,
acute
RQs
were
derived
using
a
dietarybased
and
an
oral­
based
acute
toxicity
value,
and
chronic
RQs
were
derived
using
a
dietary­
based
chronic
toxicity
value.
For
mammals,
acute
RQs
were
derived
using
an
oral­
based
acute
toxicity
value,
and
chronic
RQs
were
derived
using
a
dietary­
based
chronic
toxicity
value
and
a
calculated
dose­
based
chronic
toxicity
value
(
as
determined
using
T­
REX).
Dietary­
based
RQs
were
calculated
using
EECs
expressed
in
terms
of
residue
concentration
for
the
various
forage
categories,
and
toxicity
values
(
LC50
or
NOAEC)
are
expressed
in
units
of
dietary
concentration.
Dose­
based
RQs
were
calculated
using
a
body
weight­
adjusted
LD50
and
consumption­
weighted
equivalent
dose
sorted
by
food
source
and
body
size.
For
both
birds
and
mammals,
three
weight
categories
(
or
sizes)
were
considered.

All
toxicity
reference
values
for
terrestrial
animals
and
risk
quotients
(
RQs)
are
summarized
in
Table
3.
All
terrestrial
RQs
are
summarized
below
in
Table
4.

Table
3.
Toxicity
reference
values
for
mammals
and
birds
for
cypermethrin.

Exposure
scenario
Species
Exposure
duration
Toxicity
reference
value
Reference
Mammals
Acute
Rat
Single
oral
dose
LD50
(
M)
=
247
mg/
kg­
bw
MRID
00056800
Chronic
Rat
3­
generation
reproduction
study
NOAEC
(
toxicity
to
parents
and
offspring)
=
100
ppm
(
5
mg/
kg/
day)

LOAEC
=
(
toxicity
to
parents
and
offspring)
=
500
ppm
(
25
mg/
kg/
day)
MRID
00090040
Birds
Acute
Mallard
duck
5­
day
dietary
LC50
>
2,634
mg
a.
i./
kg
diet
MRID
90071
Acute
Bobwhite
quail
Single
oral
dose
LD50
>
2,000
mg
a.
i./
kg
body
wt
MRID
44546024
Chronic
Mallard
duck
and
Bobwhite
quail
Reproduction
study
NOAEC
=
500
ppm
LOAEC
>
500
ppm
MRID
42322902
and
MRID
42322901
a
a
The
NOAEC
and
LOAEC
values
reported
here
are
from
avian
reproduction
studies
for
permethrin.
The
available
avian
reproduction
studies
for
cypermethrin
(
MRID
90072
and
MRID
90074)
showed
no
adverse
treatment­
related
effects
to
mallards
or
bobwhite
quail;
however,
they
were
only
conducted
at
maximum
concentrations
of
50
ppm.
Although
no
effects
were
seen,
the
non­
definitive
NOAEC
value
of
>
50
ppm
could
not
be
used
to
preclude
chronic
risk
to
avian
species,
and
the
NOAEC
value
for
permethrin
was
used
to
demonstrate
low
risk
to
birds
resulting
from
cypermethrin
use.
Permethrin
data
are
considered
to
be
suitable
surrogate
data
for
cypermethrin
because
both
chemicals
are
pyrethroids,
they
are
structurallysimilar
compounds
with
similar
modes
of
action,
and
both
are
expected
to
be
of
low
chronic
toxicity
to
birds.

Table
4.
Risk
quotient
ranges
for
various
usage
scenarios
for
cypermethrin.

Avian
Species
Mammalian
Species
Crop
Acute
Dose­
based
a,
b
Acute
Dietary­
based
a,
b
Chronic
Dietary­
based
c
Acute
Dose­
based
Chronic
Dietary­
based
Chronic
Dose­
based
Cotton
<
0.01
­
0.08
<
0.01
­
0.04
0.01
­
0.21
<
0.01
­
0.19
d
0.07
 
1.07
e
0.06
 
9.27e
10
Table
4.
Risk
quotient
ranges
for
various
usage
scenarios
for
cypermethrin.

Avian
Species
Mammalian
Species
Crop
Acute
Dose­
based
a,
b
Acute
Dietary­
based
a,
b
Chronic
Dietary­
based
c
Acute
Dose­
based
Chronic
Dietary­
based
Chronic
Dose­
based
Lettuce
<
0.01
­
0.06
<
0.01
­
0.03
0.01
­
0.15
<
0.01
­
0.14
d
0.05
­
0.77
0.04
 
6.69e
Canola
<
0.01
­
0.05
<
0.01
­
0.02
0.01
­
0.13
<
0.01
­
0.11
d
0.04
­
0.65
0.04
 
5.61e
Pecans
<
0.01
­
0.07
<
0.01
­
0.03
0.01
­
0.18
<
0.01
­
0.16
d
0.06
­
0.90
0.05
 
7.80e
a
All
reported
RQs
are
actually
less
than
the
reported
values
because
they
are
based
on
toxicity
reference
values
expressed
by
inequality
signs
(
LD50
>
2,000
mg/
kg­
bw
and
LC50
>
2,634
ppm).

b
All
acute
RQ
values
are
below
the
LOC
for
acute
risk
(
0.5),
acute
restricted
use
(
0.2),
and
endangered
species
(
0.1).
c
All
chronic
RQ
values
are
below
the
LOC
for
chronic
risk
(
1).
d
Acute
RQ
value
exceeds
the
LOC
for
endangered
species
(
0.1).
e
Chronic
RQ
value
exceeds
the
LOC
for
chronic
risk
(
1).

1.
Avian
Species
All
dose­
based
(
RQ
range
=
<
0.01
­
<
0.08)
and
dietary­
based
RQs
(
RQ
range
=
<
0.01
­
<
0.04)
for
acute
risk
to
avian
species
are
below
the
LOC
for
acute
risk
(
0.5),
acute
restricted
use
(
0.2),
and
endangered
species
(
0.1)
for
the
maximum
spray
application
scenarios
considered
in
this
risk
assessment
(
Table
4).
In
addition,
all
dietary­
based
chronic
RQs
for
avian
species
are
below
the
chronic
risk
LOC
(
1)
(
RQ
range
=
<
0.01
­
<
0.21;
Table
4).
Dose­
based
RQs
for
chronic
risk
to
avian
species
could
not
be
calculated
because
there
were
no
acceptable
dose­
based
toxicity
values
for
birds
available.

2.
Mammalian
Species
Based
on
the
maximum
spray
application
scenarios
for
all
crops
considered
in
this
risk
assessment,
dosebased
RQs
for
acute
risk
to
mammalian
species
do
exceed
the
LOC
for
endangered
species
(
0.1),
but
not
for
acute
risk
(
0.5)
or
acute
restricted
use
(
0.2)
(
RQ
range
=
<
0.01
­
0.19;
Table
4).
Specifically,
cypermethrin
use
does
appear
to
pose
an
acute
risk
on
cotton
(
RQ
range
=
<
0.01
­
0.19;
Table
4),
lettuce
(
RQ
range
=
<
0.01
­
0.14;
Table
4),
canola
(
RQ
range
=
<
0.01
­
0.11;
Table
4),
and
pecans
(
RQ
range
=
<
0.01
­
0.16;
Table
4).
For
cotton
uses
there
is
acute
endangered
species
risk
to
small
mammals
feeding
on
short
grass
(
RQ
=
0.19)
and
broadleaf
plants/
small
insects
(
RQ
=
0.11),
and
medium­
sized
mammals
feeding
on
short
grass
(
RQ
=
0.16).
For
lettuce
uses,
there
is
acute
endangered
species
risk
to
small
and
medium­
sized
mammals
feeding
on
short
grass
(
RQs
=
0.14
and
0.12,
respectively).
For
canola
uses,
there
is
acute
endangered
species
risk
to
small
and
medium­
sized
mammals
feeding
on
short
grass
(
RQs
=
0.11
and
0.10,
respectively).
For
pecan
uses,
there
is
acute
endangered
species
risk
to
small
and
medium­
sized
mammals
feeding
on
short
grass
(
RQs
=
0.16
and
0.13,
respectively).

Dietary­
based
RQs
for
acute
risk
to
mammalian
species
could
not
be
calculated
because
there
were
no
acceptable
dietary­
based
toxicity
values
for
mammals
available.

For
all
crop
scenarios
considered
in
this
risk
assessment,
only
the
dietary­
based
RQ
for
chronic
risk
to
mammalian
species
feeding
on
short
grass
exceeds
the
chronic
risk
LOC
(
1)
for
the
maximum
spray
application
to
cotton
(
RQ
=
1.07;
Table
4).
However,
all
other
chronic
dietary­
based
RQs
for
all
crop
scenarios
are
below
the
LOC
(
RQ
range
=
0.04
to
0.90;
Table
4).
Dose­
based
RQs
for
chronic
risk
to
mammalian
species
do
exceed
the
chronic
LOC
(
RQ
range
=
0.04
to
9.27;
Table
4)
for
all
crop
scenarios.
Specifically,
dose­
based
RQs
for
all
sizes
of
mammals
feeding
on
short
grass,
tall
grass,
and
broadleaf
11
plants/
small
insects
exceed
the
chronic
risk
LOC
for
use
of
cypermethrin
on
cotton
(
RQ
ranges
=
4.24
to
9.27,
1.94
to
4.25,
and
2.39
to
5.21,
respectively),
lettuce
(
RQ
ranges
=
3.06
to
6.69,
1.40
to
3.07,
and
1.72
to
3.76,
respectively),
canola
(
RQ
ranges
=
2.57
to
5.61,
1.18
to
2.57,
and
1.44
to
3.15,
respectively),
and
pecans
(
RQ
ranges
=
3.57
to
7.80,
1.64
to
3.57,
and
2.01
to
4.39,
respectively).
All
dose­
based
RQs
are
below
the
chronic
risk
LOC
for
mammals
feeding
on
fruits/
pods/
large
insects
or
seeds.

B.
Risk
Description
­
Interpretation
of
Direct
Effects
Based
on
the
revised
analyses,
exposure
of
terrestrial
organisms
to
cypermethrin
spray
applications
relative
to
the
use
patterns
identified
in
this
assessment
is
not
expected
to
result
in
acute
and
chronic
risk
to
listed
and
non­
listed
birds
and
reptiles.
However,
there
is
acute
and
chronic
risk
to
mammals.

1.
Avian
Species
As
might
be
expected
from
the
available
toxicity
studies
that
demonstrated
that
cypermethrin
is
practically
non­
toxic
to
avian
species
on
an
acute
oral
and
dietary
basis
(
toxicity
reference
values:
LD50
>
2,000
mg/
kgbw
and
LC50
>
2,634
ppm),
none
of
the
predicted
acute
dose­
based
or
dietary­
based
EECs
exceed
the
most
sensitive
toxicity
endpoints,
suggesting
that
avian
mortality
is
unlikely
and
exposure
to
cypermethrin
does
not
appear
to
pose
an
acute
risk
(
all
RQs
 
0.08).
In
addition,
given
that
all
chronic
dietary­
based
RQs
are
below
the
LOC
(
RQ
range
=
<
0.01
­
<
0.21),
chronic
risk
to
avian
species
also
appears
to
be
low.

It
should
be
noted
that
some
uncertainty
regarding
acute
and
chronic
risk
to
birds
does
exist.
Both
acute
dose­
based
and
acute
dietary­
based
RQs
were
based
on
toxicity
reference
values
that
were
expressed
using
inequality
signs
(>)
and
a
NOAEC
of
500
ppm
was
used
to
determine
chronic
risk
to
birds,
despite
that
a
LOAEC
was
not
established
(
there
were
no
statistically
significant
effects
at
this
highest
treatment
level).
Therefore,
both
acute
and
chronic
risks
are
likely
to
be
overestimated.
However,
the
use
of
these
conservative
estimates
of
toxicity
for
birds
still
did
not
result
in
any
LOC
exceedances.

In
addition,
the
NOAEC
value
of
500
ppm
used
to
estimate
risk
to
avian
species
is
from
two
avian
reproduction
studies
for
permethrin
(
MRID
42322902
and
MRID
42322901).
The
available
avian
reproduction
studies
for
cypermethrin
(
MRID
90072
and
MRID
90074)
showed
no
adverse
treatment­
related
effects
to
mallards
or
bobwhite
quail.
However,
they
were
only
conducted
at
maximum
concentrations
of
50
ppm.
Although
no
effects
were
seen
in
either
study,
if
the
non­
definitive
NOAEC
(>
50
ppm)
value
from
the
avian
reproduction
studies
with
cypermethrin
was
used,
uncertainty
would
be
high
because
risk
to
avian
species
could
not
be
precluded;
chronic
dietary
RQs
could
exceed
the
chronic
risk
LOC
and
range
from
<
0.13
to
<
2.14
for
cotton,
<
0.10
to
<
1.54
for
lettuce,
<
0.08
to
<
1.29
for
canola,
and
<
0.11
to
<
1.80
for
pecans.
Subsequently,
the
NOAEC
value
for
permethrin
was
used
to
demonstrate
low
risk
to
birds
resulting
from
cypermethrin
use.
Permethrin
data
are
considered
to
be
suitable
surrogate
data
for
cypermethrin
because
both
chemicals
are
pyrethroids,
they
are
structurally­
similar
compounds
with
similar
modes
of
action,
and
both
are
expected
to
be
of
low
chronic
toxicity
to
birds.

1.
Mammalian
Species
Based
on
the
submitted
acute
oral
toxicity
study
on
mammals,
cypermethrin
is
categorized
as
moderately
toxic
to
mammals
on
an
acute
oral
basis
(
LD50
=
247
mg/
kg­
bw).
As
might
be
expected
from
this
acute
dose­
based
study
with
rats,
there
are
some
slight
exceedances
of
the
acute
endangered
species
LOC
(
0.1),
primarily
for
risk
to
small
and
medium­
sized
mammals
feeding
on
short
grass
(
for
all
crops).
The
only
other
acute
LOC
exceedance
is
for
cotton,
where
the
RQ
for
small
mammals
feeding
on
broadleaf
plants/
small
insects
exceeds
the
acute
endangered
species
LOC.
This
suggests
that
mammalian
mortality
could
possibly
result
upon
exposure
to
cypermethrin
in
the
environment,
and
that
cypermethrin
use
does
appear
to
pose
an
acute
risk
on
cotton
(
RQ
range
=
<
0.01
­
0.19),
lettuce
(
RQ
range
=
<
0.01
­
0.14),
canola
(
RQ
range
=
<
0.01
­
0.11),
and
pecans
(
RQ
range
=
<
0.01
­
0.16).
The
highest
estimated
upper­
bound
dose­
based
EEC
(
102
12
mg/
kg­
bw
for
small
mammals
that
feed
on
short
grass)
under
the
most
conservative
application
scenario
considered
in
this
risk
assessment
(
spray
applications
to
cotton)
is
slightly
less
than
one­
fifth
the
adjusted
LD50
value
for
small
mammals
(
543
mg/
kg­
bw).
Based
on
the
highest
acute
dose­
based
RQ
value
of
0.19
(
for
dose­
based
acute
risk
to
small
mammals
feeding
on
short
grass
under
the
cotton
use
scenario),
a
cypermethrin
application
rate
of
~
0.05
lb
a.
i./
A
would
be
required
to
ensure
that
all
acute
RQ
values
are
less
than
the
LOCs
for
all
mammals
under
all
crop
scenarios
(
approximately
half
of
the
current
rate
of
0.1
lb
a.
i./
A).

The
NOAEC
value
of
100
ppm
(
5
mg/
kg/
day)
from
the
3­
generation
reproduction
study
(
MRID
00090040)
was
based
on
decreased
body
weight
gain
in
parents
( 
3%
and
 
7%
from
controls
for
males
and
females,
respectively,
at
the
500
ppm
level;
p 
0.05)
and
pups
( 
4.0%
from
controls
at
the
500
ppm
level;
p 
0.01).
Based
on
this
NOAEC
value,
only
the
dietary­
based
RQ
for
chronic
risk
to
mammalian
species
feeding
on
short
grass
exceeds
the
chronic
risk
LOC
(
1)
for
the
maximum
spray
application
to
cotton
(
RQ
=
1.07);
all
other
chronic
dietary­
based
RQs
for
all
crop
scenarios
considered
in
this
risk
assessment
are
below
the
LOC
(
RQ
range
=
0.04
to
0.90).

Dose­
based
RQs
for
chronic
risk
to
mammalian
species
do
exceed
the
chronic
LOC
(
RQ
range
=
0.04
to
9.27)
for
all
crop
scenarios.
Specifically,
dose­
based
RQs
for
all
sizes
of
mammals
feeding
on
short
grass,
tall
grass,
and
broadleaf
plants/
small
insects
exceed
the
chronic
risk
LOC
for
use
of
cypermethrin
on
all
crop
scenarios
considered,
while
all
dose­
based
RQs
are
below
the
chronic
risk
LOC
for
mammals
feeding
on
fruits/
pods/
large
insects
or
seeds.
These
analyses
indicate
that
mammals
are
at
chronic
risk
and
that
adverse
outcomes
(
decreased
growth
in
parents
and
offspring)
may
result
from
dietary
and
oral
exposure
to
cypermethrin.
The
highest
estimated
upper­
bound
dose­
based
EEC
(
102
mg/
kg­
bw
for
small
mammals
that
feed
on
short
grass)
under
the
most
conservative
application
scenario
considered
in
this
risk
assessment
(
spray
applications
to
cotton)
is
about
10
times
higher
than
the
adjusted
NOAEL
for
small
mammals
(
11
mg/
kg­
bw).
Based
on
the
highest
RQ
value
of
9.27
(
for
dose­
based
chronic
risk
to
small
mammals
feeding
on
short
grass
under
the
cotton
use
scenario),
a
cypermethrin
application
rate
of
~
0.01
lb
a.
i./
A
would
be
required
to
ensure
that
all
acute
and
chronic
RQ
values
are
less
than
the
LOCs
for
all
mammals
under
all
crop
scenarios.

One
source
of
uncertainty
for
this
risk
assessment
is
that
the
dietary­
based
chronic
RQs
suggest
a
lower
risk
to
mammals
than
do
the
dose­
based
chronic
RQs.
In
general,
dose­
based
estimates
of
toxicity
are
the
basis
of
risk
conclusions
since
they
are
body­
weight
specific
and
typically
present
a
more
conservative
estimate
of
risk
(
higher
RQs),
although
the
dietary­
based
estimates
do
provide
further
insight
into
potential
risks
of
some
compounds.
The
dose­
based
approach
considers
the
uptake
and
absorption
kinetics
of
a
gavage
toxicity
study
to
approximate
exposure
associated
with
uptake
from
a
dietary
matrix.
Toxic
response
is
a
function
of
duration
and
intensity
of
exposure.
For
many
compounds
a
gavage
dose
represents
a
very
short­
term
high
intensity
exposure.
Although
the
dose­
based
estimates
may
not
reflect
reality
in
that
animals
do
not
receive
a
gavage
while
feeding,
it
is
possible
that
a
short­
duration,
high­
intensity
exposure
could
occur
associated
with
feeding
on
a
agricultural
field
since
many
animals
may
gorge
themselves
when
food
items
are
available.
While
the
dietary­
based
estimates
may
suggest
greater
"
realism",
they
too
suffer
from
some
uncertainties.
Primarily,
the
dietary­
based
approach
assumes
that
animals
in
the
field
are
consuming
food
at
a
rate
similar
to
that
of
confined
laboratory
animals
despite
the
fact
that
energy
content
in
food
items
differs
between
the
field
and
the
laboratory
as
does
the
energy
requirements
of
wild
and
captive
animals.

To
bound
the
estimates
of
risk
to
mammals
resulting
from
acute
and
chronic
exposure
to
cypermethrin,
RQs
using
mean
Kenaga
residue
values
rather
than
upper­
bound
values
were
calculated.
Using
the
nonconservative
mean
residue
values,
implying
that
higher
predicted
residue
values
are
expected
half
the
time,
dose­
based
RQs
still
exceed
the
chronic
LOC
for
cotton
(
maximum
RQ
=
3.27),
lettuce
(
maximum
RQ
=
2.36),
canola
(
maximum
RQ
=
1.98),
and
pecans
(
maximum
RQ
=
2.75),
while
no
dietary­
based
chronic
RQs
(
maximum
RQ
=
0.38)
or
acute
RQs
(
maximum
RQ
=
0.07)
exceed
the
LOCs.
However,
relying
on
the
mean
Kenaga
residue
values
for
calculating
RQs
would
not
protect
birds
and
mammals
that
consume
food
items
that
have
residues
on
the
higher
end
of
the
residue
distribution.
An
analysis
of
the
residue
distribution
13
for
the
different
food
items
using
input
values
from
Fletcher
et
al.
(
1994)
and
assuming
a
log­
normal
distribution
of
residues
on
food
items
shows
that
the
mean
Kenaga
values
range
from
about
the
62­
87
percentile
indicating
that
up
to
38%
of
the
higher­
end
food
item
residue
estimates
are
not
captured
by
using
the
mean
Kenaga
values.
In
contrast,
for
the
upper­
end
Kenaga
residue
estimates,
about
3­
13%
of
the
upperend
residue
estimates
were
not
captured.
This
highlights
the
fact
that
the
upper­
end
Kenaga
values
are
not
a
maximum
exposure
level.

IV.
References
Fletcher,
J.
S.,
J.
E.
Nellesson
and
T.
G.
Pfleeger.
1994.
Literature
review
and
evaluation
of
the
EPA
foodchain
(
Kenaga)
nomogram,
an
instrument
for
estimating
pesticide
residues
on
plants.
Environ.
Tox.
And
Chem.
13(
9):
1383­
1391.

Hoerger,
F.
and
E.
E.
Kenaga.
1972.
Pesticide
residues
on
plants:
correlation
of
representative
data
as
a
basis
for
estimation
of
their
magnitude
in
the
environment.
IN:
F.
Coulston
and
F.
Corte,
eds.,
Environmental
Quality
and
Safety:
Chemistry,
Toxicology
and
Technology.
Vol
1.
George
Theime
Publishers,
Stuttgart,
Germany.
pp.
9­
28.

T­
REX.
2005.
Terrestrial
Residue
Exposure
Model
(
T­
REX),
Version
1.2.3.
August
8,
2005.
Environmental
Fate
and
Effects
Division,
Office
of
Pesticide
Programs,
U.
S.
Environmental
Protection
Agency,
Washington,
D.
C.

Willis
and
McDowell.
1987.
Pesticide
persistence
on
foliage.
Environ.
Contam.
Toxicol.
100:
23­
73.

Effect
of
Buffers
on
Spray
Drift
The
screening­
level
risk
assessment
indicates
that
peak
EECs
exceed
acute
levels­
of­
concern
for
all
aquatic
taxa
considered.
The
ecological
risk
assessment
includes
an
evaluation
of
the
relative
contribution
of
runoff
and
spray
drift
to
the
exposure
simulated
by
PRZM/
EXAMS.
A
hypothetical
scenario
was
run
(
for
use
on
NC
cotton)
in
which
application
of
cypermethrin
resulted
in
no
spray
drift.
The
resulting
EEC
of
2.2
µ
g
a.
i./
L,
which
represented
transport
of
cypermethrin
to
water
via
runoff
and
erosion
alone,
is
high
enough
to
exceed
the
acute
LOC
for
all
aquatic
taxa.

The
effect
of
a
150­
foot
spray
buffer
on
potential
exposure
from
runoff
and
erosion
cannot
currently
be
quantified.
Presumably,
the
mass
of
cypermethrin
that
would
be
applied
to
that
portion
the
field
within
150
feet
of
a
water
body
would
be
less
than
that
applied
to
the
rest
of
the
crop,
and
would
decline
with
distance.
However,
the
PRZM
model
is
an
edge­
of­
field
model
which
cannot
simulate
an
untreated
area
between
the
field
and
the
receiving
water
body.

The
expected
effect
of
a
spray
buffer
on
exposure
through
spray
drift
can
be
quantified
using
the
AgDRIFT
model,
which
was
developed
using
extensive
field
data
collected
by
the
Spray
Drift
Task
Force.
This
is
important
because
while
the
EEC
from
PRZM/
EXAMS
used
in
the
screening
model
represents
a
1­
in­
10­
year
exposure
from
combined
runoff/
erosion
and
spray
drift,
the
output
from
AgDRIFT
can
be
made
to
represent
the
amount
of
exposure
from
spray
drift
that
could
occur
any
time
a
pesticide
is
applied.

AgDRIFT
modeling
for
cypermethrin
indicates
that
the
exposure
from
spray
drift
alone
could
be
sufficient
to
exceed
levels
of
concern
for
aquatic
organisms,
and
that
implementation
of
a
spray
buffer
can
reduce
that
exposure
significantly.
Using
typical
spray
conditions
(
10
ft.
release
height,
10
mph
wind,
and
a
fine­
tomedium
droplet
size
distribution
[
DSD]),
the
AgDRIFT
model
simulates
a
concentration
of
0.73
µ
g
a.
i./
L
in
14
the
standard
pond
from
spray
drift
if
no
buffer
zone
is
observed.
Risk
quotients
calculated
with
this
EEC
would
exceed
the
acute
LOCs
of
0.5
for
freshwater
and
estuarine/
marine
fish
and
invertebrates.

The
table
below
shows
the
effect
of
spray
buffers
on
the
concentration
of
cypermethrin
that
AgDRIFT
simulates
in
the
standard
pond.
These
values
reflect
the
typical
spray
conditions
described
above,
and
an
application
rate
of
0.1
lb
ai/
acre:

Buffer
(
ft)
0
50
100
150
200
Concentration
(
µ
g
a.
i./
L)
0.73
0.44
0.31
0.24
0.20
When
a
buffer
of
150
feet
is
simulated,
the
resulting
concentration
of
cypermethrin
in
the
pond
resulting
from
drift
alone
is
reduced
by
two­
thirds.
This
is
sufficient
to
reduce
the
EEC
below
the
acute
level­
of­
concern
of
0.5
for
estuarine/
marine
fish
(
RQ
=
0.24
µ
g
a.
i./
L/
0.95
µ
g
a.
i./
L
=
0.25).
This
reduction
would
not
reduce
the
risk
quotients
for
drift
alone
below
the
acute
LOC
for
freshwater
fish
(
RQs
of
0.61),
but
the
reduction
in
exposure
could
lead
to
lower
levels
of
mortality,
and
perhaps
be
sufficiently
protective
for
less
sensitive
species.
The
toxicity
reference
values
for
freshwater
and
estuarine/
marine
invertebrates
(
LC50
=
0.0036
and
0.0048
µ
g
a.
i./
L,
respectively)
are
so
low
that
even
a
two­
third
reduction
in
exposure
still
results
in
RQs
far
above
the
LOC
(
RQ
=
67
and
50,
respectively).

The
use
of
a
spray
buffer
would
reduce
exposure
under
conditions
other
than
the
typical
conditions
described
above,
but
conditions
more
conducive
to
spray
drift
could
result
in
unacceptable
exposure
from
drift
alone
regardless
of
the
buffer.
For
instance,
if
the
wind
speed
(
10
mph)
and
release
height
(
10
ft)
are
kept
the
same
as
above,
but
a
very
fine­
to­
fine
DSD
is
simulated
instead
of
a
fine­
to­
medium
DSD,
much
greater
exposure
to
cypermethrin
could
result.

Buffer
(
ft)
0
50
100
150
200
Concentration
(
µ
g
a.
i./
L)
1.7
1.2
0.96
0.8
0.68
The
resulting
amount
of
spray
drift
would
lead
to
more
than
three
times
the
exposure
at
150
feet
than
if
the
fine­
to­
medium
DSD
were
used,
and
the
resulting
EECs
would
still
exceed
the
LOC
for
all
aquatic
taxa.

In
summary,
the
maintenance
of
a
150­
foot
spray
buffer
can
result
in
significant
reductions
in
exposure
to
aquatic
organisms,
provided
that
application
occurs
during
typical
conditions
and
the
DSD
used
for
application
is
not
too
fine.
Such
exposure
from
spray
drift
alone
can
be
expected
any
time
cypermethrin
is
applied,
regardless
of
whether
a
significant
runoff/
erosion
event
happens
soon
after.
The
spray
buffer
is
an
important
mitigation
measure,
therefore,
even
if
any
reduction
in
runoff
and
erosion
it
might
lead
to
cannot
be
quantified.

Incident
Reports
for
Cypermethrin
15
Incident
Table
1.
Terrestrial
Incident
Reports
Involving
Cypermethrin.
Location
and
Incident
#
Date
Organisms
Involved
Formulation
Certainty
Index
a
Legality
b
Description
I011348­
001
8/
31/
9
9
Sparrows
Ustad
(
an
Indian
pesticide
containing
cypermethrin)
1
UN
A
report
on
the
Internet
(
Third
World
Network)
described
a
massive
killing
of
sparrows
in
a
small
village
in
Bangladesh
as
the
result
of
Ustad
(
an
Indian
pesticide
containing
cypermethrin).
In
eggplant
and
pointed
gourd
fields
there
was
a
spraying
of
Ustad
the
night
before.
The
sparrows
ate
insects
that
had
died
from
the
spraying
and
they,
in
turn,
died
by
the
thousands.
An
original
estimate
was
that
5000
had
died
but
later
indications
were
that
the
number
was
much
higher.
Residents
were
shocked
by
the
massive
kill
of
these
birds
and
protests
were
made
against
the
use
of
pesticides.
However,
many
toxic
pesticides
are
used
in
the
area,
including
some
illegal
products.
It
is
unlikely
that
cypermethrin
was
the
cause
because
it
has
low
acute
toxicity
to
vertebrates.

I000340­
009
10/
9/
9
2
Goats
AMMO
2.5
­
EC
2
UN
The
report
implied
that
an
unspecified
number
of
goats
may
have
suffered
illness
(
incapacitation)
due
to
nearby
application
of
cypermethrin
(
drift)
to
cotton.
Insufficient
information
was
given
in
the
incident
report
to
lend
a
greater
certainty
to
the
cause
of
the
event.

I000103­
010
3/
7/
90
Sparrows,
mockingbird,
and
barred
owl
Demon
­
Spray
1
UN
According
to
the
investigative
report,
11
dead
birds
were
found
near
a
private
dwelling
(
9
sparrows,
a
mockingbird,
and
a
barred
owl).
It
was
suspected
that
the
mortality
was
due
to
toxicosis.
Four
birds
were
selected
for
necropsy
(
1
mockingbird
and
3
sparrows).
The
premises
had
been
periodically
sprayed
for
termites
for
8
years,
the
most
recent
being
2
month
prior
to
the
event
with
cypermethrin.
Earlier
treatments
had
been
done
with
lindane.
Analysis
of
brain
ChE
activity
gave
normal
results.
Residue
analysis
of
gizzard/
crop
contents
revealed
the
presence
of
Heptachlor
Epoxide
and
a
significant
amount
of
Dieldrin.
there
was
an
insufficient
amount
of
brain
tissue
left
to
make
a
residue
analysis
of
the
brain
for
Dieldrin.
According
to
the
report
brain
tissue
residue
of
1ppm
is
considered
significant
but
body
residues
are
usually
many
times
greater
than
brain
residue.
The
birds
were
observed
to
undergo
convulsions
just
before
dying.
Crop/
gizzard
content
residue
analysis
revealed
Dieldrin
at
7480
ppb
and
Hrptachlor
Epoxide
at
710
ppb.
There
was
no
evidence
of
organophosphate,
carbamate,
lindane,
or
cypermethrin
pesticides;
it
is
unlikely
that
cypermethrin
contributed
to
the
observed
bird
mortality.

I000340­
006
12/
3/
9
2
Dog
Cynoff
­
EC
2
UN
According
to
the
investigative
report,
a
dog
was
dipped
and
also
exposed
to
pyrethroid
products.
The
dog's
illness
(
incapacitation)
was
suspected
to
be
due
to
one
of
these
exposures.
Since
the
report
indicated
exposure
to
permethrin
and
cypermethrin,
which
are
known
toxicants
to
animals,
it
is
possible
that
the
observed
incapacitation
of
the
dog
was
due
to
either
or
both
of
the
chemicals.
Insufficient
information
was
given
in
the
incident
report
to
lend
a
greater
certainty
to
the
cause
to
the
event.

I000340­
002
12/
18/
92
Cat
Cynoff
­
EC
3
RU
According
to
the
report,
a
cat
was
exposed
to
toxic
fumes
of
cypermethrin
by
following
applicator
around
as
he
worked
and
was
incapacitated.
According
to
the
incident
report
the
cat
was
in
the
treatment
area
where
it
could
be
exposed
to
toxic
fumes
of
cypermethrin.
This
exposure
was
probably
responsible
for
the
observed
illness
in
the
cat.
Insufficient
information
was
given
in
the
report
to
lend
a
greater
certainty
to
the
cause
of
the
event.
16
Incident
Table
1.
Terrestrial
Incident
Reports
Involving
Cypermethrin.
Location
and
Incident
#
Date
Organisms
Involved
Formulation
Certainty
Index
a
Legality
b
Description
a
Certainty
index
scoring
reflects
the
likelihood
that
the
pesticide
was
responsible
for
the
alleged
damage.
Highly
probable
(
4);
Probable
(
3);
Possible
(
2);
Unlikely
(
1);
Unrelated
(
0).
b
Legality:
RU=
Registered
Use,
MA=
Misuse
(
accidental),
MI=
Misuse
(
intentional),
UN=
Undetermined
N/
R:
not
reported
Incident
Table
2.
Aquatic
Incident
Reports
Involving
Cypermethrin.
Location
and
Incident
#
Date
Organisms
Involved
Formulation
Certainty
Index
a
Legality
b
Description
I008737­
001
8/
8/
98
Lobster
Raid
Fogger
K
Ready­
to­
Use
3
RU
In
a
5000
gal.
saltwater
tank
in
Cocoa
Beach,
FL
32931,
an
owner,
Rancher/
Breeder/
Farmer
found
800
lobsters
dead
and
another
25
lobsters
still
alive
in
the
tank.
He
used
a
product
(
EPA
Reg.
No.
4822­
452):
RAID
Concentrate
­
Deep
Reach
Fogger
in
a
room
adjacent
to
the
tank
room
then
closed
the
tank
room
door
for
the
night,
but
did
not
place
a
towel
under
the
door.
An
air
conditioner
was
turned
off.
He
does
not
have
UV/
ozone
sterilization.
He
has
added
another
200­
300
lobsters
to
this
same
tank
and
they
seem
fine.
He
has
tested
water,
ammonia
nitrites,
nitrate,
pH
and
all
are
within
normal
limits.
He
could
not
locate
the
EPA
Reg.
No.
on
the
container.
Breeder
has
changed
1000
gallons
in
the
tank
and
is
expecting
another
immediate
shipment
of
lobsters
and
is
wondering
if
its
O.
K.
to
add
them
to
the
tank!

Evidently,
the
RAID
Fogger
spread
(
creeped)
under
the
door
and
into
the
Lobster
Tank
Room
where
it
contacted
the
uncovered
tank.
The
LC/
50
for
fish:
(
rainbow
trout)
=
2.0
to
2.8
ug/
l.
It
then,
obviously
settled
because
after
the
incident
another
200­
300
lobster
were
added
to
the
tank
and
the
product
was
not
a
hazard.
I001031­
001
4/
26/
94
Bluegill,
Carp,
Catfish,
Largemouth
Bass
Demon
TC
­
EC
4
UN
This
fish
kill
resulted
from
the
application
of
Demon
TC
as
a
termite
barrier
around
a
home
in
Henderson,
Kentucky.
Underground
drainage
tile
had
been
installed
around
the
home
to
divert
water
to
a
pond
50
feet
away,
and
the
night
following
the
application
of
Demon
there
was
a
heavy
rainfall
which
resulted
in
dumping
some
of
the
Demon
into
the
pond.
Approximately
44
fish
we
re
killed.
The
pond
in
back
of
the
house
was
estimated
to
be
1­
2
acres
in
area,
and
a
sample
of
water
taken
3
days
after
the
rainfall,
where
the
drainage
tile
pipe
enters
the
water,
contained
4.1
ppb
cypermethrin.
I007107­
003
2/
7/
97
Minnows
N/
R
4
UN
This
incident
is
one
of
the
incidents
stated
on
a
consolidated
report
submitted
by
the
Pesticide
Investigation
Unit,
California
Dept.
of
Fish
and
Game
for
the
year
1997.
One
thousand
Gambusia
(
minnows)
reported
dead
in
Placer
County
on
2­
7­
1997.
Pesticide
Investigation
Unit,
California
Department
of
Fish
and
Game
confirmed
through
its
findings
that
the
gambusia
mortality
was
caused
by
cypermethrin
poisoning.
I006971­
001
2/
6/
98
Bass,
bluegill,
shad
Demon
TC
­
EC
2
UN
Zeneca
reported
that
Tennessee
Dept.
of
Agriculture
was
contacted
about
fish
kills
in
several
small
ponds
fed
by
a
small
stream.
State
investigators
estimated
2,200
dead
fish
(
i.
e.,
bass,
bluegill,
shad)
were
impacted
along
with
various
other
unspecified
aquatic
organisms.
Soil
and
water
samples
were
obtained,
Analysis
showed
trace
levels
of
chlorpyrifos
and
permethrin,
and
exceptionally
high
levels
of
cypermethrin.
Initial
investigation
focused
on
a
local
pest
control
applicator.
A
multi­
agency
investigation
team
later
focused
its
attention
to
alternative
explanations.
State
analysis
showed
high
levels
of
cypermethrin
in
both
soil
and
water.
17
Incident
Table
2.
Aquatic
Incident
Reports
Involving
Cypermethrin.
Location
and
Incident
#
Date
Organisms
Involved
Formulation
Certainty
Index
a
Legality
b
Description
I009966­
002
2/
9/
98
Bluegill,
bass,
crappie,
catfish,
minnow,
carp,
shad
Demon
TC
­
EC
4
MA
A
fish
kill
was
reported
on
February
9,
1998
in
Chattanooga,
the
result
of
a
termiticide
containing
cypermethrin
entering
Rogers
Branch
and
its
un­
named
tributaries.
The
Tennessee
Wildlife
Resources
Association
assessed
the
cost
of
the
dead
fish
at
$
609.33.
Civil
penalties
and
damages
were
assessed,
suggesting
misuse
of
the
pesticide.

Further
information
was
provided
by
a
6(
a)(
2)
report
from
Zenaca
Ag
Products
(
I006971­
001).
They
claim
that
their
investigation
indicate
that
the
kill
was
not
likely
the
result
of
any
labeled
use
of
Demon
TC
or
of
the
minor
spill
reported
on
the
property
in
November
­
December
1997.
They
claim
the
exposure
characteristics
suggest
"
introduction
of
relatively
massive
amounts
of
chemical
directly
into
the
water
course."

No
analyses
were
submitted
with
the
report,
but
the
circumstances
of
the
kill
and
the
assessment
of
civil
penalties
indicate
that
exposure
to
this
chemical
was
the
probable
cause
of
the
kill.
I010444­
004
6/
23/
00
Fishunspecified
N/
R
3
MA
To
comply
with
6(
a)
2
regulations,
FMC
reported
an
incident
that
occurred
in
Silver
Spring,
MD
(
the
location
was
not
given
in
the
report
but
was
known
to
this
writer).
A
treatment
tank
was
being
cleaned
out
by
an
applicator
and
the
washings
entered
Rock
Creek,
causing
a
fish
kill
extending
from
an
area
near
Walter
Reed
Hospital
to
the
Potomac
River.
Initial
estimates
were
that
between
1000
and
150,000
fish
were
killed,
but
estimates
were
later
revised
to
10,000.
The
Maryland
Dept.
of
Agricuoture
found
50
ppb
cypermethrin
in
the
water,
although
no
analyses
of
the
fish
were
made.
I013857­
011
2/
25/
03
Fishunspecified
N/
R
3
MI
To
comply
with
6(
a)
2
requirements,
Syngenta
reported
that
the
February
25,
2003,
issue
of
the
Independent
(
London)
carried
an
account
of
a
large
fish
kill
in
the
river
Slea,
in
Lincolnshire.
According
to
this
newspaper,
someone
had
dumped
Cypermethrin
into
surface
water
drains
at
an
industrial
site,
infecting
13
miles
of
the
river
and
causing
the
death
of
100,000
fish.
The
newspaper
account
gave
no
report
of
an
analysis
being
made
of
the
fish
or
of
the
water,
but
it
is
presumed
that
there
was
some
reason
for
the
allegation.
I004876­
011
8/
5/
91
Crayfish
and
stoneflies
N/
R
4
MA
There
was
nearly
a
complete
kill
of
crayfish
and
stoneflies
for
a
6
mile
stretch.
I000011­
001
4/
3/
92
Fishunspecified
Demon
TC
­
EC
2
RU
Pond
150­
200
ft
from
treatment
site
experienced
fishkill
via
alleged
underground
stream
under
home,
after
termite
control.
Magnitude
of
fish
kill
not
reported.
I015094­
001
4/
24/
04
Fishunspecified
Prevail
FT
­
EC
2
RU
FMC
6(
a)(
2)
incident
report
stated
that
a
contractor
applied
Prevail
(
cypermethrin)
on
a
horizontal
soil
surface
where
a
concert
slab
was
to
be
poured.
5000
dead
fish
were
found
in
a
stream
1/
2
to
1
mile
from
the
construction
site.
No
analyses
were
given.
Since
the
report
did
not
give
any
analysis
of
either
the
fish
or
the
creek
water,
only
a
possible
index
can
be
given.
a
Certainty
index
scoring
reflects
the
likelihood
that
the
pesticide
was
responsible
for
the
alleged
damage.
Highly
probable
(
4);
Probable
(
3);
Possible
(
2);
Unlikely
(
1);
Unrelated
(
0).
b
Legality:
RU=
Registered
Use,
MA=
Misuse
(
accidental),
MI=
Misuse
(
intentional),
UN=
Undetermined
N/
R:
not
reported
