Document ID: EPA-HQ-OPP-2006-0366-0004
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-08-11T04:00Z

Page
1
of
50
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
Date:
6­
April­
2006
MEMORANDUM
SUBJECT:
Bifenthrin:
Human
Health
Risk
Assessment
for
Proposed
Uses
on
Cilantro,
Leafy
Brassica
Greens
(
subgroup
5b),
Tuberous
and
Corm
Vegetables
(
Subgroup
1c),
Dried
Shelled
Peas
and
Beans
(
except
Soybean)
(
Subgroup
6c)
and
Tobacco.
PC
Code:
128825,
DP
Barcodes:
DP310088,
DP310089,
DP310874,
DP313738,
DP313817,
DP313818.

Regulatory
Action:
Section
3
Registration
Action
Risk
Assessment
Type:
Single
Chemical
Aggregate
FROM:
Mary
Clock­
Rust,
Biologist
George
Kramer,
Ph.
D.,
Chemist
Sarah
Levy,
M.
S.,
Chemist
Mark
I.
Dow,
Ph.
D.,
Biologist
P.
V.
Shah,
Ph.
D.,
Toxicologist
Registration
Action
Branch
1
(
RAB1)
Health
Effects
Division
(
HED)
(
7509C)
and
Sheila
Piper,
Chemist
Chemistry
and
Exposure
Branch
(
CEB)
HED
(
7509C)

THROUGH:
PV
Shah,
Ph.
D.,
Branch
Senior
Scientist
RAB1
HED
(
7509C)

TO:
George
LaRocca,
Chemical
Review
Manager
Barbara
Madden,
Minor
Use
Team
Registration
Division
(
RD,
7505C)

The
Interregional
Research
Project
No.
4
(
IR­
4)
and
the
FMC
Corporation
have
requested
registration
of
the
insecticide
bifenthrin
for
use
on
cilantro
(
coriander)
and
tuberous
and
corm
vegetables
(
Subgroup
1c)
(
Arracacha,
arrowroot,
Chinese
artichoke,
Jerusalem
artichoke,
edible
canna,
cassava
(
bitter
and
sweet),
chayote
(
root),
chufa,
dasheen
(
taro),
ginger,
leren,
potato,
sweet
potato,
tanier,
turmer,
yam
bean,
true
yam),
dried
shelled
peas
and
beans
(
subgroup
6c)
and
Leafy
Brassica
Greens
(
Subgroup
5b).
FMC
also
requests
a
label
amendment
for
use
on
tobacco.
Page
2
of
50
This
memorandum
serves
as
the
HED's
estimates
of
exposure
and
risk
to
humans
from
the
proposed
applications
of
bifenthrin.

The
HED
of
the
Office
of
Pesticide
Programs
(
OPP)
is
charged
with
estimating
the
risk
to
human
health
from
exposure
to
pesticides.
The
RD
of
OPP
has
requested
that
HED
evaluate
hazard
and
exposure
data
and
conduct
dietary,
occupational,
residential,
and
aggregate
exposure
assessments,
as
needed,
to
estimate
the
risk
to
human
health
that
will
result
from
the
proposed
uses
of
bifenthrin
in/
on
cilantro,
tuberous
and
corm
vegetables,
dried
beans
and
peas,
leafy
Brassica
and
label
amendment
use
of
tobacco.

A
summary
of
the
findings
and
an
assessment
of
human
health
risk
resulting
from
the
proposed
uses
of
bifenthrin
are
provided
in
this
document.
The
hazard
characterization
was
provided
by
P.
V.
Shah
(
RAB1);
the
residue
chemistry
review
was
provided
by
George
Kramer
and
Sarah
Levy
(
RAB1);
the
dietary
exposure
assessment
was
provided
by
Sheila
Piper
(
CEB);
the
occupational/
residential
exposure
assessment
was
provided
by
Mark
Dow
(
RAB1);
the
drinking
water
assessment
was
provided
by
Jose
Melendez
of
the
Environmental
Fate
and
Effects
Division
(
EFED);
the
aggregate
exposure
and
risk
assessment
were
provided
by
Mary
Clock­
Rust
(
RAB1).
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
3
of
50
1.0
Executive
Summary
Reference:
Revised
Preliminary
HED
Chapter
for
the
Bifenthrin
Tolerance
Reassessment
Eligibility
Decision
(
TRED).
PC
Code:
128825
DP
Barcode:
D283796.
J.
Liccione.
12/
04/
2002.

Background
Bifenthrin
is
a
neurotoxic
insecticide
acting
through
direct
contact
and
ingestion,
having
a
slight
repellent
effect.
The
primary
biological
effects
of
bifenthrin
and
other
pyrethroids
on
insects
and
vertebrates
are
inhibition
of
the
voltage­
gated
Ca2+
channels
coupled
with
a
stimulatory
effect
on
the
voltage­
gated
Na+
channels.
All
pyrethroids
act
as
axonic
poisons,
affecting
both
the
peripheral
and
central
nervous
systems,
and
share
similar
modes
of
action.
Pyrethroids,
including
bifenthrin,
stimulate
repetitive
action
in
the
nervous
system
by
binding
to
voltage­
gated
sodium
channels,
prolonging
the
sodium
ion
permeability
during
the
excitatory
phase
of
the
action
potential.
This
action
leads
to
spontaneous
depolarizations,
augmented
neurotransmitter
secretion
rate
and
neuromuscular
block,
which
ultimately
results
in
paralysis
of
the
insect.

Bifenthrin,
formulated
as
an
emulsifiable
concentrate
(
EC)
or
wettable
powder
(
WP),
and
granular
(
G)
has
permanent
tolerances
for
foliar
use
on/
in
artichoke,
imported
banana,
head
and
stem
Brassica
vegetables,
cabbage,
caneberry,
field
and
sweet
corn,
cotton,
eggplant,
citrus,
cucurbits,
grape,
herbs,
hops,
lettuce,
nuts,
succulent
bean
and
pea,
pear,
bell
and
non­
bell
pepper,
rapeseed,
spinach,
strawberry,
tomato
and
edible
podded
legumes.

Current
tolerances
(
ranging
from
0.05­
10
ppm)
are
established
in
40
CFR
§
180.442(
a)
for
various
plant
commodities
and
livestock
for
bifenthrin
(
2­
methyl
[
1,1'­
biphenyl]­
3­
yl)
methyl­
3­(
2­
chloro­
3,3,3,­
trifluoro­
1­
propenyl)­
2,2­
dimethylcyclopropanecarboxylate.
Time­
limited
tolerances
for
orchard
grass
and
sweet
potato
roots
(
0.05
ppm)
have
been
established
in
conjunction
with
Section
18
Emergency
Exemptions
[
40
CFR
§
180.442(
2b)].
A
tolerance
of
0.05
ppm
is
established
for
residues
of
bifenthrin
in
food
handling
establishments
[
40
CFR
§
180.442(
2)]

A
Tolerance
Reassessment
Eligibility
Decision
(
TRED)
was
issued
for
bifenthrin
in
2002
(
reference
above).
The
TRED
examined
all
registered
uses
of
bifenthrin.
The
background
information
and
conclusions
reported
in
the
2002
TRED
(
including
exposure
from
dietary,
occupational
and
residential
uses)
have
been
summarized
and
incorporated
into
this
risk
assessment.
For
more
details,
see
the
2002
TRED
or
relevant
memoranda
for
each
section.

Hazard
Characterization
Bifenthrin
has
a
moderate
order
of
acute
toxicity
via
the
oral
route
(
Category
II)
and
a
low
order
of
acute
toxicity
via
the
dermal
route
(
Category
III)
of
exposure.
There
are
no
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
4
of
50
acute
inhalation
studies
on
bifenthrin
technical;
however,
acceptable
studies
on
the
end­
use
products
are
available.
Bifenthrin
has
a
low
vapor
pressure.
It
is
neither
an
eye
nor
skin
irritant,
nor
is
it
a
dermal
sensitizer.

Bifenthrin
produces
characteristic
pyrethroid
neurotoxicity.
Tremors
have
been
observed
in
developmental
toxicity
studies
in
the
rat
and
rabbit,
a
2­
generation
rat
reproduction
toxicity
study,
subchronic
toxicity
studies
in
the
rat
and
dog,
acute
and
subchronic
neurotoxicity
rat
studies,
a
21­
day
toxicity
dermal
rat
study,
chronic
oral
toxicity
studies
in
the
rat
and
dog,
and
a
mouse
oncogenicity
study.
The
subchronic
and
chronic
oral
toxicity
studies
in
dogs
and
rats
demonstrate
neurotoxicological
responses
of
similar
magnitude.
Staggered
gait
and
exaggerated
hindlimb
flexion
were
noted
in
a
21­
day
dermal
toxicity
study
in
the
rat.
The
neurotoxicity
of
bifenthrin
has
been
supported
by
the
results
of
acute
and
subchronic
neurotoxicity
studies
in
the
rat.
FOB
findings
were
observed
in
these
neurotoxicity
studies.
FOB
findings
consisted
of
tremors,
abnormal
posture,
splayed
hindlimbs,
staggered
gait,
altered
activity,
altered
landing
foot­
splay,
twitching,
uncoordinated
movement/
ataxia,
and
convulsions.

Bifenthrin
is
neither
a
developmental
nor
a
reproductive
toxicant.
Bifenthrin
has
been
evaluated
for
potential
developmental
effects
in
the
rat
(
following
gavage
or
dietary
administration)
and
in
the
rabbit
(
gavage
administration).
Maternal
toxicity
included
neurological
effects
(
tremors
in
rats
and
rabbits;
head
and
forelimb
twitching
in
rabbits).
There
were
no
developmental
effects
of
biological
significance
in
either
species.

The
potential
reproductive
toxicity
of
bifenthrin
was
examined
in
a
two­
generation
reproduction
study
in
the
rat.
Tremors
were
noted
only
in
females
of
both
generations
with
one
parental
generation
rat
observed
to
have
clonic
convulsions.
Administration
of
bifenthrin
did
not
result
in
reproductive
or
offspring
toxicity.

Bifenthrin
was
negative
in
most
tests
for
mutagenicity.
It
was
marginally
mutagenic
with
and
without
S9
activation
in
the
mouse
lymphoma
forward
gene
mutation
assay.
This
finding
has
not
been
confirmed
in
a
repeat
test.
There
is
also
inconclusive,
but
presumptive,
evidence
that
bifenthrin
was
mutagenic
in
the
S9­
activated
phase
of
the
Chinese
Hamster
Ovary
Cell
(
CHO)
gene
mutation
assay,
however,
this
study
was
classified
as
unacceptable.

There
was
no
conclusive
evidence
of
carcinogenic
potential
of
bifenthrin
in
the
rat.
A
mouse
oncogenicity
study
provided
some
evidence
for
carcinogenic
potential
in
this
species.
In
the
mouse
oncogenicity
study,
high­
dose
(
81.3
mg/
kg/
day)
males
showed
a
highly
significant
increased
incidence
of
urinary
bladder
tumors.
Other
findings
in
the
mouse
study
included
a
dose­
related
trend
of
increased
combined
incidences
of
adenoma
and
adenocarcinoma
of
the
liver
(
males
only),
and
increased
incidences
of
bronchioalveolar
adenomas
and
adenocarcinomas
of
the
lung
in
females
at
some,
but
not
all
dose
levels
relative
to
their
controls.
HED's
Carcinogenicity
Peer
Review
Committee
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
5
of
50
(
CPRC)
has
characterized
bifenthrin
as
Category
C
(
possible
human
carcinogen)
primarily
on
the
basis
of
a
mouse
study
in
which
the
Cancer
Assessment
Review
Committee
(
CARC)
(
1992)
recommended
that
for
the
purpose
of
risk
characterization,
the
reference
dose
(
RfD)
approach
should
be
used
for
quantification
of
human
cancer
risk.

Several
dermal
absorption
studies
on
bifenthrin
are
available;
each
study
was
considered
acceptable
for
regulatory
purposes
when
taken
in
conjunction
with
the
other
studies.
The
Hazard
Identification
and
Review
Committee
(
HIARC)
recommended
a
dermal
absorption
rate
of
25%
based
on
the
weight­
of
the­
evidence
available
for
structurally
related
pyrethroids.

Dose
Response
Assessment
and
Food
Quality
Protection
Act
(
FQPA)
Decision
The
HED
Hazard
Identification
and
Assessment
Review
Committee
(
HIARC)
met
on
June
25,
2002
to
select
endpoints
for
risk
assessment
and
to
evaluate
the
potential
for
increased
susceptibility
of
infants
and
children
from
exposure
to
bifenthrin.
No
appropriate
acute
dietary
endpoints
were
available
to
quantify
risk
to
females
13­
50
years
of
age
from
a
single­
dose
administration
of
bifenthrin.
However,
an
acute
reference
dose
(
aRFD)
of
0.033
mg/
kg/
day,
relevant
to
the
general
population
including
infants
and
children,
and
based
on
observation
of
mortality
(
females
only),
clinical
and
Functional
Observation
Battery
(
FOB)
findings,
and
differences
in
motor
activity,
was
selected
from
an
acute
neurotoxicity
study
in
rats
for
acute
risk
assessment.
The
acute
RfD
is
based
on
the
no­
observed
adverse
effect
level
(
NOAEL)
of
32.8
mg/
kg/
day
divided
by
an
uncertainty
factor
(
UF)
of
1000
(
10x
for
interspecies
extrapolation,
10x
for
intraspecies
variations,
and
10x
for
an
incomplete
database
for
lack
of
a
developmental
neurotoxicity
study.

HIARC
concluded
that,
based
on
reliable
data,
an
additional
traditional
database
UF
of
3X
is
required
for
all
repeated­
dose
exposure
scenarios
to
address
deficiencies
in
the
databases
for
bifenthrin
(
i.
e.,
the
lack
of
a
developmental
neurotoxicity
study
(
DNT)
because
existing
data
indicate
that
the
results
of
the
DNT
study
might
impact
the
current
toxicology
endpoint
selection
and
RfDs).
An
UFDB
of
10X
is
applied
to
single
dose
exposure
scenarios
(
i.
e.,
acute
RfD)
to
account
for
the
lack
of
the
DNT.

The
short­
and
intermediate­
term
incidental
oral
and
inhalation
endpoints
are
based
on
observations
of
an
increased
incidence
of
tremors
in
male
and
female
dogs
in
a
90­
day
oral
toxicity
study.
A
chronic
dietary
RfD
of
0.004
mg/
kg/
day
was
determined
from
the
1­
year
oral
dog
study
that
demonstrated
increased
incidence
of
tremors
in
both
sexes.
The
chronic
RfD
is
based
on
the
NOAEL
of
1.3
mg/
kg/
day
divided
by
an
UF
of
300
(
10x
for
interspecies
extrapolation,
10x
for
intraspecies
variations,
and
3x
for
an
incomplete
database
for
lack
of
a
developmental
neurotoxicity
study).
The
results
of
the
1­
year
dog
toxicity
study
were
also
the
basis
for
the
determination
of
the
long­
term
inhalation
endpoint.
An
inhalation
absorption
default
factor
of
100%
was
used
for
risk
assessment
purposes,
since
the
endpoint
was
derived
from
an
oral
study.
The
21­
day
rat
dermal
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
6
of
50
toxicity
study
was
used
to
select
short­,
intermediate­
and
long­
term
dermal
endpoints;
clinical
signs
included
staggered
gait
and
exaggerated
hindlimb
flexion.

The
Food
Quality
Protection
Act
(
FQPA)
requires
the
Agency
to
consider
potential
special
sensitivity
to
infants
and
children
from
exposure
to
bifenthrin.
The
HED
FQPA
Safety
Factor
Committee
(
SFC)
met
on
July
15
and
22,
2002
to
evaluate
the
hazard
and
exposure
data
for
bifenthrin
with
regard
to
making
a
decision
on
the
additional
safety
factor
for
the
protection
of
infants
and
children.
Acceptable
developmental
studies
in
the
rat
and
rabbit
revealed
no
increased
susceptibility
of
rat
or
rabbit
fetuses
following
in
utero
exposure
to
bifenthrin.
In
addition,
there
was
no
evidence
of
increased
susceptibility
of
young
rats
in
the
reproduction
study
with
bifenthrin.

The
1X
safety
factor
has
been
applied
to
all
dietary
and
residential
non­
dietary
exposure
scenarios.
The
acute
and
chronic
RfD
modified
by
a
FQPA
Safety
Factor
is
a
population
adjusted
dose
(
PAD).
Therefore,
the
acute
PAD
(
aPAD)
for
bifenthrin
is
0.033
mg/
kg/
day,
and
the
chronic
PAD
(
cPAD)
for
bifenthrin
is
0.004
mg/
kg/
day.

The
FQPA
Committee
noted
that
there
were
no
residual
uncertainties
in
the
exposure
databases.
The
dietary
food
exposure
assessment
was
refined
using
percent
crop
treated
(
CT)
information,
and
anticipated
residue
(
AR)
values
calculated
from
the
available
monitoring
data
and
field
trial
results.
Dietary
drinking
water
exposure
is
based
on
conservative
modeling
estimates,
and
the
HED
Residential
standard
operating
procedures
(
SOPs),
in
conjunction
with
some
chemical
specific
data,
were
used
to
assess
residential
handler
and
post­
application
exposure
to
adults
and
children.
These
assessments
will
not
underestimate
the
exposure
and
risks
posed
by
bifenthrin.

Dietary
Exposure
Assessment
Acute
and
chronic
dietary
exposure
and
risk
assessments
were
conducted
using
the
Dietary
Exposure
Evaluation
Model­
Food
Commodity
Intake
Database
(
DEEM­
FCID
 
,
Version
2.03)
which
uses
food
consumption
data
from
the
U.
S.
Department
of
Agriculture's
(
USDA)
Continuing
Surveys
of
Food
Intakes
by
Individuals
(
CSFII)
from
1994­
1996
and
1998.

Acute
Dietary
Exposure
and
Risk
A
Tier
3,
acute
probabilistic
dietary
exposure
and
risk
assessment
was
conducted
for
all
registered
(
and
pending)
food
uses
and
drinking
water.
ARs
were
developed
based
on
1998­
2003
USDA's
Pesticide
Data
Program
(
PDP)
monitoring
data,
Food
and
Drug
Administration
(
FDA)
data,
or
field
trial
data
for
bifenthrin.
ARs
were
further
refined
using
%
CT
data
and
processing
factors
where
appropriate.

EFED
calculated
the
ground
and
surface
drinking
water
Tier
1
estimated
drinking
water
concentrations
(
EDWCs)
for
bifenthrin
using
the
screening
concentration
in
ground
water
(
SCI­
GROW)
and
FQPA
Index
Reservoir
Screening
Tool
(
FIRST)
models.
EECs
in
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
7
of
50
ground
water
were
estimated
as
0.003
ppb
and
0.014
ppb
in
surface
water.
The
acute
drinking
water
concentration
of
bifenthrin
in
surface
water
(
0.014
ppb)
is
based
on
the
application
of
bifenthrin
to
lettuce
at
the
highest
application
rate
(
0.5
lb
ai/
A/
season).

The
acute
dietary
exposure
estimates
for
food
and
drinking
water
are
below
HED's
level
of
concern
(<
100%
aPAD)
at
the
99.9th
percentile
of
exposure.
Bifenthrin
dietary
exposure
at
the
99.9th
percentile
for
food
and
drinking
water
for
the
U.
S.
population
is
21%
of
the
aPAD
and
41%
of
the
aPAD
for
children
1­
2
yrs,
the
most
highly
exposed
population
subgroup.
These
estimates
include
drinking
water.

Chronic
Dietary
Exposure
and
Risk
A
refined
chronic
dietary
exposure
assessment
was
also
conducted
for
the
supported
food
uses
of
bifenthrin
and
drinking
water
using
single
point
estimates
of
anticipated
bifenthrin
residues
for
food
and
drinking
water.
The
estimated
surface
water
concentration
of
0.014
ppb,
based
on
application
to
lettuce
at
the
highest
application
rate,
was
also
used
for
the
chronic
dietary
assessment.

The
chronic
dietary
exposure
estimates
for
food
and
drinking
water
are
below
HED's
level
of
concern
(<
100%
cPAD)
for
the
U.
S.
population
and
all
population
subgroups.
Bifenthrin
dietary
exposure
for
food
and
drinking
water
for
the
U.
S.
population
is
6%
of
the
cPAD
and
18%
of
the
cPAD
for
children
1­
2
yrs,
the
most
highly
exposed
population
subgroup.
These
estimates
include
drinking
water.

Cancer
Dietary
Risk
The
CARC
(
1992)
recommended
that
for
the
purpose
of
risk
characterization,
the
reference
dose
(
RfD)
approach
should
be
used
for
quantification
of
human
risk.
The
chronic
exposure
analysis
revealed
<
100%
RfD,
and
it
is
assumed
that
the
chronic
dietary
endpoint
is
protective
for
cancer
dietary
exposure.

Residential
Exposure
and
Risk
Bifenthrin
has
both
indoor
and
outdoor
residential
uses.
Adults
are
potentially
exposed
to
bifenthrin
residues
during
residential
application
of
bifenthrin.
Adults
and
children
are
potentially
exposed
to
bifenthrin
residues
after
application
(
post­
application)
of
bifenthrin
products
in
residential
settings.
Risk
estimates
were
generated
for
residential
handler
exposures,
and
potential
post­
application
contact
with
lawn,
soil,
and
treated
indoor
surfaces
using
HED's
Draft
SOPs
for
Residential
Exposure
Assessment,
and
dissipation
data
from
a
turf
transferable
residue
(
TTR)
study.
These
estimates
are
considered
conservative,
but
appropriate,
since
the
study
data
were
generated
at
maximum
application
rates.

Residential
Handler
Risk
Estimates
Short­
to
intermediate­
term
dermal
and
inhalation
exposures
may
occur
for
residential
handlers
of
bifenthrin
products.
Although
residential
handler
risks
from
inhalation
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
8
of
50
exposures
to
bifenthrin
gas/
vapor
are
considered
unlikely,
since
the
vapor
pressure
of
bifenthrin
is
low,
inhalation
exposure
was
assessed
for
aerosols/
particulates
during
residential
mixing,
loading,
and
application
of
granular
products.
Short­
and
intermediateterm
handler
MOEs
estimated
for
combined
dermal
and
inhalation
exposures
were
 
300,
and
therefore,
do
not
exceed
HED's
level
of
concern.

Residential
Post­
Application
Risk
Estimates
Adults
and
children
may
be
potentially
exposed
to
bifenthrin
residues
after
application
of
bifenthrin
products
in
residential
settings.
Short­
and
intermediate­
term
post­
application
dermal
exposures
for
adults,
and
short­
and
intermediate­
term
post­
application
dermal
and
incidental
oral
exposures
for
children
are
anticipated.
Risk
estimates
were
generated
for
potential
contact
with
lawn,
soil,
and
treated
indoor
surfaces.
Short­
and
intermediateterm
risks
estimated
for
post­
application
exposure
do
not
exceed
HED's
level
of
concern
for
adults
and
children.
Combined
oral
and
dermal
exposures
do
not
exceed
HED's
level
of
concern
for
short­
term
exposures
for
children.
Combined
adult
handler
and
postapplication
risk
estimates
(
inhalation
and
dermal)
associated
with
homeowner
applied
liquids
do
not
exceed
HED's
level
of
concern.

Aggregate
Risk
Because
there
is
the
potential
for
short­
and
intermediate­
term,
non­
dietary
postapplication
exposure
of
children
and
adults
to
bifenthrin
when
used
as
a
residential
treatment,
aggregate
risk
was
assessed.
Short­
and
intermediate­
term
aggregate
(
dietary
+
residential)
MOEs
for
the
general
U.
S.
population
and
any
subpopulation
of
the
general
U.
S.
population
are
at
least
340.
This
value
does
not
exceed
HED's
level
of
concern
(
MOE
>
300).
Chronic
(>
6
months)
non­
dietary
post­
application
exposure
to
bifenthrin
as
a
residential
treatment
is
considered
unlikely;
therefore,
chronic
aggregate
risk
assessments
were
not
performed.

Occupational
Handler
Risk
Based
upon
the
proposed
use
pattern,
HED
expects
the
most
highly
exposed
occupational
pesticide
handlers
(
mixers,
loaders,
applicators)
to
be
1)
mixer/
loader
using
open
pour
loading
of
liquids;
2)
mixer/
loader
using
open
pour
loading
of
granules;
3)
an
aerial
applicator
and
4)
an
applicator
using
open­
cab,
ground­
boom
spray
equipment.
Estimates
for
short­
and
intermediate­
term
occupational
risks
were
calculated.
Provided
that
mixer/
loaders
wear
protective
gloves,
all
MOEs
are
above
100.
The
lowest
MOE
for
occupational
handlers
was
650
for
mixer/
loaders
supporting
aerial
application.
Therefore,
the
estimated
risks
for
occupational
handlers
do
not
exceed
HED's
levels
of
concern
(
MOE
>
100).

Occupational
Post­
Application
Risk
Based
on
the
proposed
use
pattern,
HED
has
calculated
post­
application
exposure
and
risk
for
workers
exposed
to
bifenthrin
residues
following
treatment.
Workers
engaging
in
activities
such
as
hand
harvesting,
topping,
stripping
and
irrigation
activities
were
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
9
of
50
assessed.
Standard
assumptions
were
incorporated
into
the
assessment
to
reflect
conservative
risk
estimates.
The
MOE
for
the
theoretically
most
highly
exposed
postapplication
agricultural
activity
is
410,
and
does
not
exceed
HED's
level
of
concern.
All
other
identified
post­
application
activities
are
expected
to
have
lower
exposures
and
therefore
greater
MOEs.

HED
Recommendations
The
tolerances
proposed
by
the
registrants
in
the
current
petitions
are
listed
below,
along
with
HED's
recommended
tolerance
levels.

Provided
revised
Sections
B
and
F
are
submitted,
the
residue
chemistry
and
toxicology
databases
support
unconditional
registration
and
permanent
tolerances
for
the
following:

Crop
Commodity
Proposed
Tolerance
(
ppm)
Recommended
Tolerance
(
ppm)
Comments
(
correct
commodity
definition)

Tuberous
and
corm
vegetables,
subgroup
1C
0.1
0.05
Vegetable,
tuberous
and
corm,
subgroup
1C
Brassica,
leafy
greens,
subgroup
5B1
3
3.5
Turnip
greens1
3
3.5
Turnip,
greens
Pea
and
bean,
dried
shelled,
except
soybean,
subgroup
0.1
0.15
Pea
and
bean,
dried
shelled,
except
soybean,
subgroup
6C
Cilantro,
leaves
5.0
6.0
Coriander,
leaves
Cilantro,
dried
leaves
30.0
25
Coriander,
dried
leaves
Coriander,
seed
5.0
5.0
1
Turnip
greens
will
be
removed
from
Crop
Group
2:
Leaves
of
root
and
tuber
vegetables
group
[
40
CFR
180.41
(
2)],
and
will
become
a
member
of
Crop
Group
5:
Brassica
leafy
vegetables
[
40
CFR
180.41
(
5)].
It
will
also
be
a
member
of
Crop
Subgroup
5B:
Leafy
Brassica
greens
(
Commodity
Reviewers
Guide,
B.
Schneider,
14­
JUN­
2002).
Until
that
time,
"
turnip,
greens"
should
have
a
separate
tolerance.

Revised
Sections
F
with
the
correct
tolerance
levels
and
commodity
definitions
should
be
submitted
where
appropriate.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
10
of
50
2.0
Ingredient
Profile
2.1
Summary
of
Proposed
Uses
There
are
currently
four
bifenthrin
end­
use
products
(
EPs)
registered
to
FMC
for
use
on
food/
feed
crops.
One
is
a
2
lb/
gal
EC
formulation
marketed
under
the
trade
name
Capture
®
2EC
Insecticide/
Miticide
(
EPA
Reg.
No.
279­
3069)
and
another
is
a
1.15%
G
formulation
marketed
under
the
trade
name
Capture
®
1.15G
Insecticide
(
EPA
Reg.
No.
279­
3244).
IR­
4
is
supporting
the
use
of
the
2
lb/
gal
EC
on
tuberous
and
corm
vegetables
(
subgroup
1C),
Brassica
leafy
greens
(
subgroup
5B),
dried
peas
and
beans
(
subgroup
6C),
cilantro,
and
the
use
of
the
1.15%
G
on
tuberous
and
corm
vegetables.
FMC
is
also
proposing
amending
the
label
for
the
2
lb/
gal
EC
to
include
a
non­
food/
feed
use
on
tobacco.
Example
labels
were
provided
and
the
proposed
use
directions
are
summarized
below
in
Table
2.1.

Table
2.1
Summary
of
Proposed
Use
Directions
for
Bifenthrin.

Application
Timing,
Type
and
Equipment
Formulation
[
EPA
reg.
No.]
Single
rate(
lb
ai/
A)
Max
Number
Applications
per
Season
Max.
Seasonal
Application
Rate
(
lb
ai/
A)
PHI
(
Days)
Use
Directions
and
Limitations
1
Tuberous
and
Corm
Vegetables
(
Crop
subgroup
1C)
In­
furrow
application
at
planting
Ground
equipment
1.15%
G
[
279­
3244
]
or
2
lb/
gal
EC
[
279­
3069]
0.3
1
Directed
foliar
applications
during
tuber
formation
Ground
equipment
2
lb/
gal
EC
[
279­
3069]
0.1
2
0.5
21
The
minimum
RTI
is
21
days.

Brassica
leafy
Greens
(
subgroup
5B)
Post­
emergence
broadcast
foliar
applications
Ground
or
aerial
equipment
2
lb/
gal
EC
[
279­
3069]
0.1
4
0.4
7
The
minimum
RTI
is
7
days
Dried
Beans
(
subgroup
6C)
Post­
emergence
broadcast
foliar
applications
Ground
or
aerial
equipment
2
lb/
gal
EC
[
279­
3069]
0.1
3
0.3
14
No
minimum
RTI
is
specified
Dried
Peas
(
subgroup
6C)
Post­
emergence
broadcast
foliar
applications
Ground
or
aerial
equipment
2
lb/
gal
EC
[
279­
3069]
0.1
2
0.2
14
A
minimum
RTI
is
not
specified
Cilantro
(
Coriander)
Post­
emergence
broadcast
foliar
applications
Ground
or
aerial
equipment
2
lb/
gal
EC
[
279­
3069]
0.1
5
0.5
3
The
minimum
RTI
is
7
days.

Tobacco
Pre­
transplant
soil
application
Ground
equipment
2
lb/
gal
EC
[
279­
3069]
0.1
1
NS
NS
Apply
pretransplant
soil
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
11
of
50
Application
Timing,
Type
and
Equipment
Formulation
[
EPA
reg.
No.]
Single
rate(
lb
ai/
A)
Max
Number
Applications
per
Season
Max.
Seasonal
Application
Rate
(
lb
ai/
A)
PHI
(
Days)
Use
Directions
and
Limitations
1
At
transplant
water
drench
application
Ground
equipment
0.1
1
NS
Broadcast
foliar
applications
up
to
and
including
lay­
by
Ground
equipment
0.05
NS
NS
application
and
broadcast
foliar
applications
in
a
minimum
of
10
gal/
A,
and
water
drench
application
in
50­
200
gal/
A
1
Crops
with
bifenthrin
tolerances
may
be
rotated
at
any
time,
and
all
other
corps
may
be
rotated
30
days
following
the
final
bifenthrin
application.
NS
=
not
specified.

Conclusions.
The
proposed
use
directions
for
tuberous
and
corm
vegetables,
leafy
Brassica
greens,
dried
peas
and
beans,
and
cilantro
are
adequately
supported
by
the
available
field
trials
on
potatoes,
mustard
greens,
dried
beans
and
peas,
and
cilantro;
however,
the
use
directions
for
dried
beans
and
peas
should
be
amended
to
specify
a
minimum
RTI
of
7
days.
The
available
tobacco
field
trials
will
also
support
the
use
of
the
EC
formulation
on
tobacco;
however,
the
use
directions
should
be
amended
to
specify
the
maximum
number
of
foliar
applications
allowed
and
the
maximum
seasonal
use
rate.
The
available
tobacco
field
trials
will
support
use
of
the
2
lb/
gal
EC
as
either
a
broadcast
preplant
soil
application
at
up
to
0.1
lb
ai/
A
or
an
in­
furrow
water
drench
application
at
transplant
at
up
to
0.1
lb
ai/
A,
followed
by
a
single
broadcast
foliar
application
up
to
layby
at
up
to
0.1
lb
ai/
A,
for
a
maximum
seasonal
use
rate
of
0.2
lb
ai/
A.
These
data
will
also
support
the
use
of
the
1.15%
G
formulation
to
tobacco
as
a
single
broadcast
pre­
plant
soil
application
at
up
to
0.1
lb
ai/
A.
A
revised
Section
B
should
be
submitted.

2.2
Structure
and
Nomenclature
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
12
of
50
Table
2.2
Nomenclature
of
Bifenthrin
Compound
O
O
Cl
F
3
C
CH
3
CH
3
C
H
3
Common
name
Bifenthrin
Company
experimental
names
Capture
®

Molecular
weight
422.88
IUPAC
name
2­
methylbiphenyl­
3­
ylmethyl(
Z)­(
1RS,
3RS)­
3­(
2­
chloro­
3,3,3­
trifluoroprop­
1­
enyl)­
2,2­
dimethylcyclopropanecarboxylate
or
2­
methylbiphenyl­
3­
ylmethyl(
Z)­(
1RS)­
cis­
3­(
2­
chloro­
3,3,3­
trifluoroprop­
1­
enyl)­
2,2­
dimethylcyclopropanecarboxylate
CAS
name
rel­
2­
methyl(
1,1'­
biphenyl)­
3­
yl)
methyl(
1R,
3R)­
3­((
1Z)­
2­
chloro­
3,3,3­
trifluoro­
1­
propenyl)­
2,2­
dimethylcyclopropanecarboxylate
CAS
#
82657­
04­
03
End­
use
products/
EP
2.0
lb/
gal
EC
and
1.5%
G
2.3
Physical
and
Chemical
Properties
Table
2.3
Physicochemical
Properties
of
the
Technical
Grade
Bifenthrin
Parameter
Value
Reference
Melting
range
68­
70.6
º
C
pH
NA
Density
at
24
°
C
1.26
g/
mL
Water
solubility
<
0.1
Fg/
L
Solvent
solubility
(
g/
100
mL)
8.9
in
heptane
and
methanol
125
in
acetone,
chloroform,
ether,
methylene
chloride,
and
toluene
Vapor
pressure
(
Pa)
at
25
°
C
2.41
x
10­
5
Dissociation
constant
(
pKa)
NA
Octanol/
water
partition
coefficient)
Kow
>
1
x
10
6
UV/
visible
absorption
spectrum
NA
Product
Chemistry
Chapter
of
TRED
NA
=
Not
available
3.0
Hazard
Characterization/
Assessment
References:

BIFENTHRIN
­
3rd
Report
of
the
Hazard
Identification
Assessment
Review
Committee.
TXR
No.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
13
of
50
0051570.
B.
Tarplee.
2/
19/
2003.

Revised
Preliminary
HED
Chapter
for
the
Bifenthrin
Tolerance
Reassessment
Eligibility
Decision
(
TRED).
PC
Code:
128825
DP
Barcode:
D283796.
J.
Liccione.
12/
04/
2002.

Bifenthrin
is
a
non­
systemic
insecticide/
miticide
in
the
class
of
synthetic
pyrethroids.
It
is
registered
for
use
on
a
variety
of
crops
for
the
control
of
insect
pests.

Bifenthrin
is
classified
as
Category
II
for
acute
oral
toxicity,
and
Category
III
for
acute
dermal
toxicity.
There
are
no
acute
inhalation
studies
on
bifenthrin
technical.
It
is
not
an
eye
or
skin
irritant,
or
a
dermal
sensitizer.

Bifenthrin
produces
characteristic
pyrethroid
neurotoxicity.
Tremors
have
been
observed
in
developmental
toxicity
studies
in
the
rat
and
rabbit,
a
2­
generation
rat
reproduction
study,
subchronic
toxicity
studies
in
the
rat
and
dog,
acute
and
subchronic
neurotoxicity
rat
studies,
a
21­
day
dermal
rat
study,
chronic
oral
studies
in
the
rat
and
dog,
and
oncogenicity
rat
and
mouse
studies.
FOB
findings
were
observed
in
the
acute
and
subchronic
neurotoxicity
studies
in
the
rat.

There
is
no
evidence
of
increased
susceptibility
of
rats
or
rabbits
to
in
utero
and/
or
postnatal
exposure
to
bifenthrin.

Bifenthrin
was
negative
in
most
tests
for
mutagenicity.
It
was
marginally
mutagenic
with
and
without
S9
activation
in
the
mouse
lymphoma
forward
gene
mutation
assay.
This
finding
has
not
been
confirmed
in
a
repeat
test.
There
is
also
inconclusive,
but
presumptive
evidence
that
bifenthrin
was
mutagenic
in
the
S9­
activated
phase
of
the
CHO
gene
mutation
assay
(
unacceptable
study).

The
CPRC
has
characterized
bifenthrin
as
Category
C
(
possible
human
carcinogen)
primarily
on
the
basis
of
a
mouse
study
in
which
the
high­
dose
(
600
ppm)
males
showed
a
highly
significant
increased
incidence
of
urinary
bladder
tumors.
Other
findings
in
the
mouse
study
included
a
dose­
related
trend
of
increased
combined
incidences
of
adenoma
and
adenocarcinoma
of
the
liver
(
males
only),
and
increased
incidences
of
bronchioalveolar
adenomas
and
adenocarcinomas
of
the
lung
in
females
at
50,
200
and
600
ppm
(
but
not
500
ppm)
relative
to
their
controls.
The
CARC
(
1992)
recommended
that
for
the
purpose
of
risk
characterization,
the
reference
dose
(
RfD)
approach
should
be
used
for
quantification
of
human
cancer
risk.

3.1
Hazard
and
Dose­
Response
Characterization
The
acute
toxicity
profile
for
bifenthrin
is
presented
below
in
Table
3.1.4.
The
full
toxicological
profile
is
presented
in
Attachment
1
to
this
memo.
A
summary
of
the
toxicology
of
bifenthrin
is
discussed
below.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
14
of
50
Subchronic
Toxicity
The
database
for
subchronic
toxicity
is
considered
incomplete
due
to
the
lack
of
a
DNT
study.
The
available
subchronic
oral
toxicity
studies
in
rats
and
dogs
demonstrated
the
neurotoxicity
of
bifenthrin.
Tremors
were
observed
in
rats
fed
doses
equal
to
or
greater
than
100
ppm
(
7.5
mg/
kg/
day
for
males;
8.5
mg/
kg/
day
for
females)
bifenthrin
for
90
days.
Male
and
female
dogs
administered
(
via
gelatin
capsule)
bifenthrin
at
doses
equal
to
or
greater
than
4.42
mg
ai/
kg/
day
for
up
to
13
weeks
exhibited
tremors.
Ataxia
was
noted
in
male
dogs
at
8.84
and
17.7
mg
ai/
kg/
day,
and
in
female
dogs
at
4.42
mg
ai/
kg/
day.
Languidness
occurred
primarily
at
17.7
mg
ai/
kg/
day
in
both
sexes,
but
also
occasionally
at
8.84
mg
ai/
kg/
day.
All
of
these
symptoms
occurred
more
frequently
during
the
last
3
weeks
of
the
study.
Other
dose­
related
clinical
signs
included
blinking,
mydriasis,
nystagmus,
lacrimation,
and
polypnea
(
increased
rate
of
respiration)
in
the
two
highest
dose
groups.
One
high­
dose
female
appeared
thin
and/
or
dehydrated
during
the
final
weeks
of
the
study.
A
non­
statistically
significant,
but
possibly
treatment­
related,
reduction
in
mean
body
weight
gain
was
noted
in
females
at
17.7
mg
ai
/
kg/
day
(
0.6
kg)
relative
to
the
controls
(
1.3
kg).

Neurotoxicity
Bifenthrin
produces
characteristic
pyrethroid
neurotoxicity.
Tremors
have
been
observed
in
developmental
toxicity
studies
in
the
rat
and
rabbit,
a
2­
generation
rat
reproduction
study,
subchronic
toxicity
studies
in
the
rat
and
dog,
acute
and
subchronic
neurotoxicity
rat
studies,
a
21­
day
dermal
rat
study,
chronic
oral
studies
in
the
rat
and
dog,
and
oncogenicity
rat
and
mouse
studies.
Staggered
gait
and
exaggerated
hindlimb
flexion
were
noted
in
a
21­
day
dermal
toxicity
study
in
the
rat.
The
neurotoxicity
of
bifenthrin
has
been
supported
by
the
results
of
acute
and
subchronic
neurotoxicity
studies
in
the
rat.
FOB
findings
were
observed
in
these
neurotoxicity
studies.
FOB
findings
consisted
of
tremors,
abnormal
posture,
splayed
hindlimbs,
staggered
gait,
altered
activity,
altered
landing
foot­
splay,
twitching,
uncoordinated
movement/
ataxia,
and
convulsions.
The
HIARC
concluded
that
there
is
a
concern
for
developmental
neurotoxicity
resulting
from
exposure
to
bifenthrin.
The
DNT
study
is
required
based
on
evidence
of
neurotoxicity
observed
in
the
developmental
toxicity,
2­
generation
reproduction,
acute
and
subchronic
neurotoxicity,
subchronic
and
chronic
oral
toxicity,
and
dermal
toxicity
studies.
The
requirement
of
a
DNT
study
for
bifenthrin
is
consistent
with
HIARC's
conclusion
for
other
pyrethroids,
e.
g.,
permethrin,
cyfluthrin,
and
cypermethrin.

Chronic
Toxicity
The
database
for
chronic
toxicity
is
considered
complete.
No
additional
data
are
required
at
this
time.
The
results
of
chronic
toxicity
studies
support
the
finding
of
neurotoxicity
for
bifenthrin.
Tremors
were
observed
in
both
a
1­
year
feeding
study
in
the
dog
(
LOAEL
=
2.7
mg
ai/
kg/
day
for
both
sexes;
NOAEL
=
1.3
mg
ai/
kg/
day
for
both
sexes),
in
a
combined
chronic
toxicity/
oncogenicity
dietary
study
in
the
rat
(
LOAEL
=
6.1
mg
ai/
kg/
day
for
females;
NOAEL
=
3.0
mg
ai/
kg/
day
for
males),
and
in
a
combined
chronic
toxicity/
oncogenicity
dietary
study
in
the
mouse
(
LOAEL
=
25.6
mg
ai/
kg/
day
in
males;
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
15
of
50
NOAEL
=
6.7
mg
ai/
kg/
day
in
males).

Developmental
Toxicity
A
complete
developmental
toxicity
database
exists
for
bifenthrin.
The
available
data
provided
no
indication
of
increased
susceptibility
of
(
quantitative
or
qualitative)
rats
or
rabbits
to
in
utero
and/
or
postnatal
exposure
to
bifenthrin.
In
the
prenatal
developmental
(
gavage)
toxicity
study
in
rats,
a
slight
increase
in
the
incidence
of
"
hydroureter
without
hydronephrosis"
was
observed
in
fetuses
at
the
highest
dose
tested
(
2
mg/
kg/
day);
maternal
toxicity
(
tremors)
was
also
observed
at
this
dose
level,
and
the
maternal
and
developmental
NOAELs
were
equivalent
at
1
mg/
kg/
day.
This
effect
was
not
observed
in
the
prenatal
developmental
(
dietary)
toxicity
study
in
rats;
maternal
toxicity
was
evident
at
15.5
mg
ai/
kg/
day
as
tremors
and
decreased
food
consumption,
body
weight
gains,
and
adjusted
(
for
gravid
uterine
weight)
body
weight
gains.
In
the
prenatal
developmental
toxicity
study
in
rabbits,
there
was
no
evidence
of
developmental
toxicity
at
the
highest
dose
tested
(
8
mg/
kg/
day).
Head
and
forelimb
twitching
was
observed
at
the
maternal
LOAEL
of
4
mg/
kg/
day;
the
maternal
NOAEL
was
established
at
2.67
mg/
kg/
day.

Reproductive
Toxicity
Bifenthrin
is
not
a
reproductive
toxicant
and
there
is
no
evidence
of
increased
susceptibility
of
offspring.
In
an
acceptable
two­
generation
reproduction
study
in
rats,
no
evidence
of
toxicity
was
noted
in
the
offspring
at
dietary
levels
up
to
100
ppm
(
5
mg/
kg/
day).
Parental
toxicity
(
tremors
and
decreased
body
weights)
was
observed
at
100
ppm
(
5
mg/
kg/
day),
with
a
NOAEL
of
60
ppm
(
3.0
mg/
kg/
day).

Carcinogenicity
There
was
no
conclusive
evidence
of
carcinogenic
potential
of
bifenthrin
in
the
rat.
A
mouse
oncogenicity
study
provided
some
evidence
for
the
carcinogenic
potential
of
bifenthrin
in
this
species.
In
the
mouse
oncogenicity
study,
high­
dose
males
showed
a
highly
significant
increased
incidence
of
urinary
bladder
tumors.
Other
findings
in
the
mouse
study
included
a
dose­
related
trend
of
increased
combined
incidences
of
adenoma
and
adenocarcinoma
of
the
liver
(
males
only),
and
increased
incidences
of
bronchioalveolar
adenomas
and
adenocarcinomas
of
the
lung
in
females
at
50,
200
and
600
ppm
(
but
not
500
ppm)
relative
to
their
controls.
The
CRPC
has
characterized
bifenthrin
as
Category
C
(
possible
human
carcinogen)
primarily
on
the
basis
of
the
mouse
study.
Other
findings
in
the
mouse
study
included
a
dose­
related
trend
of
increased
combined
incidences
of
adenoma
and
adenocarcinoma
of
the
liver
(
males
only),
and
increased
incidences
of
bronchioalveolar
adenomas
and
adenocarcinomas
of
the
lung
in
females
at
some,
but
not
all,
doses
relative
to
their
controls.
The
CARC
(
1992)
recommended
that
for
the
purpose
of
risk
characterization,
the
reference
dose
(
RfD)
approach
should
be
used
for
quantification
of
human
cancer
risk.

Mutagenicity
Bifenthrin
was
negative
in
most
tests
for
mutagenicity.
It
was
marginally
mutagenic
with
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
16
of
50
and
without
S9
activation
in
the
mouse
lymphoma
forward
gene
mutation
assay.
This
finding
has
not
been
confirmed
in
a
repeat
test.
There
is
also
inconclusive,
but
presumptive,
evidence
that
bifenthrin
was
mutagenic
in
the
S9­
activated
phase
of
the
CHO
gene
mutation
assay;
however,
this
was
an
unacceptable
study.

Metabolism
Bifenthrin
is
absorbed
by
the
oral
route
and
eliminated
primarily
in
the
feces
(
about
70%
within
48
hours).
Approximately
10%
of
the
administered
doses
were
excreted
in
the
urine.
Nearly
all
the
administered
dose
was
eliminated
in
urine
and
feces
within
7
days
indicating
no
retention
in
the
body.
Very
little
of
the
administered
radioactive
dose
is
expired
as
14C­
CO2.
The
major
metabolic
route
of
radiolabeled
bifenthrin
is
hydrolysis
of
the
ester
linkage
with
oxidation
of
the
resulting
alcohol
to
the
acid.
Protein
binding
of
radioactive
components
or
metabolites
increases
with
time.

Dermal
Absorption
Several
dermal
absorption
studies
on
bifenthrin
are
available;
each
study
is
considered
acceptable
for
regulatory
purposes
when
taken
in
conjunction
with
the
other
studies.
The
HIARC
recommended
a
dermal
absorption
rate
of
25%
based
on
the
weight­
of
theevidence
available
for
structurally
related
pyrethroids.

Table
3.1.4
Acute
Toxicity
Profile
 
Bifenthrin
Guideline
No./
Study
Type
MRID
No.
Results
Toxicity
Category
870.1100/
Acute
oral
toxicity
0013519
LD50
=
70.1
mg/
kg
(
 
)
;
53.8
mg/
kg
(
 
)
II
870.1200/
Acute
dermal
toxicity
00132520
LD50
>
2,000
mg/
kg
III
870.1300/
Acute
inhalation
toxicity
46029703
Data
waived.
Acceptable
atmosphere
could
not
be
generated
with
product.
IV
870.2400/
Primary
eye
irritation
00132522
Non­
irritant
IV
870.2500/
Primary
dermal
irritation
00132521
Non­
irritant
IV
870.2600/
Dermal
sensitization
00132523
Not
a
sensitizer
N/
A
3.2
FQPA
Considerations
3.2.1
Adequacy
of
the
Toxicity
Database
The
HIARC
concluded
that
the
toxicology
database
for
bifenthrin
is
not
complete
for
FQPA
assessment.
On
June
25,
2002,
the
HIARC
requested
that
a
developmental
neurotoxicity
study
in
rats
be
conducted
with
bifenthrin.

3.2.2
Evidence
of
Neurotoxicity
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
17
of
50
The
HIARC
concluded
that
there
is
a
concern
for
neurotoxicity
resulting
from
exposure
to
bifenthrin.
This
is
based
on
the
observation
of
neurotoxicity
(
clinical
signs)
in
the
acute
neurotoxicity,
subchronic
neurotoxicity,
2­
generation
reproduction,
developmental
toxicity,
dermal
toxicity,
subchronic
toxicity
and
chronic
toxicity
studies.
In
addition,
FOB
findings
were
observed
in
the
acute
and
subchronic
neurotoxicity
studies.

3.2.2.1
Acute
Neurotoxicity
Study
In
an
acute
oral
neurotoxicity
study
(
MRID
44862102),
bifenthrin
(
FMC
54800
technical,
93.7%
ai;
FMC
Ref.
No.
PL97­
592)
was
administered
by
a
single
gavage
dose
to
10
Sprague­
Dawley
rats/
sex/
dose
at
doses
of
0,
10,
35
or
75
mg/
kg,
or
0,
9.4,
32.8,
or
70.3
mg
ai/
kg/
day
(
2
control
males
and
2
control
females
were
removed
from
the
study
due
to
an
unspecified
dosing
error,
leaving
8/
sex).
The
FOB
assessment
and
motor
activity
testing
were
performed
during
the
pretest
interval,
and
on
days
0,
7
and
14.
Five
animals/
sex/
group
were
perfused
in
situ
for
neurohistological
examination
at
day
14
and
brain,
central
and
peripheral
nervous
system
tissues
from
control
and
high
dose
animals
were
examined
microscopically.

At
75
mg/
kg,
two
females
died
on
day
0,
shortly
after
dosing.
The
following
clinical
signs
were
observed
in
males
after
dosing
(#
incidences):
decreased
feces
(
1
vs.
0
control);
staggered
gait
(
1
vs.
0
control);
tremors
(
1
vs.
0
control);
and
twitching
(
3
vs.
0
control).
Females
displayed
the
following
clinical
signs
following
dosing
(#
incidences):
abdominogenital
staining
(
2
/
2
died
vs.
0
control);
clonic
convulsions
(
1
treated/
died
vs.
0
control);
chromorhinorrhea
(
2
/
2
died
vs.
0
control);
and
tremors
(
3
[
2
died]
vs.
0
control).
All
clinical
signs
of
toxicity
were
resolved
in
survivors
by
study
day
2.

The
following
FOB
home
cage
observations
were
noted
on
day
0
at
6­
8
hrs
postdosing:
whole
body
tremors
(
1
male,
1
female/
died
vs.
0
control);
abnormal
mobile
posture
(
1
male
vs.
1
control);
uncoordinated
movement/
ataxia
(
1
male
vs.
0
control);
splayed
hindlimbs
(
1
male
vs.
0
control);
convulsions
(
2
females/
2
died
vs.
0
control);
tense/
rigid
during
handling
(
1
male,
4
females/
2
died
vs.
0
controls);
and
unusual
posture
(
immobile;
1
female/
died
vs.
0
control).
Day
0
FOB
open
field
observations
included
the
following:
localized
spasms/
twitching
(
2
males
vs.
0
control);
whole
body
tremors
(
2
males,
2
females/
1
died
treated
vs.
0
control);
staggered
gait
(
1
male
vs.
0
control);
abnormal
posture
(
mobile;
1
male
vs.
0
control);
uncoordinated
movement/
ataxia
(
1
male
vs.
0
control);
splayed
hindlimbs
(
1
male
vs.
0
control);
increased
activity
(
1
female
vs.
0
control);
decreased
activity
(
1
female/
died
vs.
0
control);
convulsions
(
2
females/
1
died
vs.
0
control);
walking
on
toes
(
1
female
vs.
0
controls);
and
unusual
immobile
posture
(
1
female/
died
vs.
0
control).
Landing
foot­
splay
values
were
decreased
in
males
during
the
day
0
FOB
( 
15%,
p 
0.05).
No
treatment­
related
differences
from
controls
were
observed
in
the
FOB
assessment
in
survivors
on
study
days
7
and
14.
Mean
motor
activity
was
decreased
in
males
on
day
0
( 
36%,
not
statistically
significant),
while
motor
activity
in
the
females
was
increased
on
days
0
and
14
( 
23%
and
 
18%,
respectively;
not
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
18
of
50
statistically
significant),
although
the
day
14
increase
was
not
considered
biologically
significant.
No
treatment­
related
differences
were
observed
in
body
weights,
body
weight
gains,
gross
observations
or
neuropathological
examinations
in
any
treated
group
(
the
latter
only
examined
in
control
and
high
dose
groups).
No
treatment­
related
findings
were
observed
at
10
or
35
mg/
kg.

The
LOAEL
for
this
study
is
75
mg/
kg
(
70.3
mg
ai/
kg/
day)
based
on
mortality
(
females
only),
clinical
and
FOB
findings
and
differences
in
motor
activity.
The
NOAEL
for
this
study
is
35
mg/
kg
(
32.8
mg
ai/
kg/
day).

3.2.2.2
Subchronic
Neurotoxicity
Study
In
this
subchronic
oral
neurotoxicity
study
(
MRID
44862103),
FMC
54800
technical
(
Bifenthrin,
93.7%
ai,
batch
PL97­
592)
was
administered
continuously
in
the
diet
for
13
weeks
to
10
Sprague­
Dawley
rats/
sex/
dose
at
doses
of
50,
100
or
200
ppm
(
equivalent
to
[
M/
F]
0/
0,
2.9/
3.7,
6.0/
7.2
or
11.8/
14.6
mg/
kg).

At
100
ppm,
tremors
were
observed
during
clinical
examinations
in
8
(
28
incidences)
males
and
10
(
119
incidences)
females.
Twitching
was
observed
in
4
(
4
incidences)
males
and
2
(
5
incidences)
females.
During
the
open
field
portion
of
the
FOB,
tremors
were
observed
in
all
females
following
4
weeks
of
treatment.
In
addition,
females
displayed
decreased
(
p 
0.05)
hindlimb
grip
strength
during
weeks
8
and
13
( 
22­
25%).
One
female
died
on
day
52
as
a
result
of
kidney
inflammation;
however,
this
death
was
not
considered
treatment
related.

At
200
ppm,
tremors
were
observed
during
clinical
examinations
in
10
(
311
incidences)
males
and
10
(
336
incidences)
females.
Twitching
was
also
observed
in
10
(
76
incidences)
males
and
10
(
96
incidences)
females.
During
the
open
field
FOB,
tremors
were
observed
in
all
males
and
females
following
4
weeks
of
treatment.
In
addition,
females
displayed
increased
arousal
when
compared
to
concurrent
controls
(
3
treated
vs.
1
control).
Females
displayed
decreased
(
p 
0.05
or
0.01)
forelimb
grip
strength
( 
20­
31%)
and
hindlimb
grip
strength
( 
18­
36%),
and
increased
landing
foot­
splay
values
( 
21­
28%)
during
weeks
4,
8
and
13.
In
addition,
decreased
forelimb
grip
strength
was
observed
in
males
at
week
4
( 
27%,
not
statistically
significant),
but
not
at
later
times.

No
treatment­
related
differences
were
observed
at
any
dose
level
in
body
weights,
body
weight
gains,
food
consumption,
home
cage
FOB
examination,
motor
activity
measurements,
or
gross
or
neuropathological
examinations.

The
LOAEL
for
this
study
is
100
ppm
(
equivalent
to
6.0
mg/
kg/
day
in
males
and
7.2
mg/
kg/
day
in
females)
based
on
neuromuscular
findings
(
tremors,
changes
in
grip
strength
and
landing
foot­
splay).
The
NOAEL
is
50
ppm
(
equivalent
to
2.9
mg/
kg/
day
in
males
and
3.7
mg/
kg/
day
in
females).
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
19
of
50
3.2.2.3
Evidence
of
Neurotoxicity
From
Other
Related
Studies
3.2.3
Developmental
Toxicity
Studies
3.2.3.1
Rat
Developmental
Rat
Studies
In
a
pilot
developmental
study
(
MRID
00154482),
bifenthrin
(
88.35%
ai)
in
corn
oil
was
administered
via
gavage
to
mated
female
Sprague­
Dawley
rats
(
10/
sex/
dose)
at
dose
levels
of
0,
0.5,
1.0,
2.0,
or
2.5
mg/
kg/
day
FMC
54800
during
days
6­
15
of
gestation.
These
doses
are
equivalent
to
0,
0.44,
0.88,
1.77,
and
2.2
mg
ai/
kg/
day.
Three
of
10
rats
at
2.5
mg/
kg/
day
died
on
days
14­
15.
Tremors
were
noted
in
all
10
rats
at
2.5
mg/
kg/
day
(
days
6­
15)
and
in
9/
10
at
2.0
mg/
kg/
day
(
days
7
through
18).
Two
of
the
rats
administered
2.5
mg/
kg/
day
also
exhibited
clonic
convulsions.
Mean
body
weight
gains
were
depressed
at
2.5
mg/
kg/
day
throughout
the
study,
and
food
consumption
was
lower
( 
20%)
at
this
dose
level
during
days
6­
13.
There
were
no
differences
in
mean
body
weight
gains
or
food
consumption
in
the
lower
dose
groups
with
respect
to
the
controls.
There
were
no
treatment­
related
differences
from
controls
in
the
number
of
implantations
or
litter
size.
The
mean
number
of
resorptions
was
similar
in
the
lower
dose
groups;
at
2.5
mg/
kg/
day
it
was
somewhat
higher,
but
this
was
attributable
to
an
excessive
number
of
resorptions
in
a
single
rat.

The
maternal
LOAEL
is
1.77
mg
ai/
kg/
day
(
2.0
mg/
kg/
day)
based
on
sporadic
tremors
(
gestation
days
7­
18)
and
30%
mortality
at
2.2
mg
ai/
kg/
day
(
2.5
mg/
kg/
day).
The
maternal
NOAEL
is
0.88
mg
ai/
kg/
day
(
1.0
mg/
kg/
day).
The
developmental
LOAEL
and
NOAEL
were
not
determined;
fetuses
were
not
examined.

In
a
second
developmental
study
in
rats
(
MRID
00141201),
bifenthrin
(
88.35%
ai)
(
as
FMC
54800
technical)
in
corn
oil
was
administered
via
gavage
to
pregnant
female
Sprague­
Dawley
rats
(
25/
dose)
at
dose
levels
of
0,
0.5,
1.0,
or
2.0
mg/
kg/
day,
which
is
equivalent
to
0,
0.44,
0.88,
and
1.77
mg
ai/
kg/
day,
or
with
250
mg/
kg/
day
aspirin
(
positive
control)
in
2%
carboxymethylcellulose
during
days
6­
15
of
gestation.

Maternal
toxicity
was
characterized
as
tremors
in
18/
25
dams
at
1.77
mg
ai/
kg/
day
(
2.0
mg/
kg/
day)
during
days
10­
19.
There
were
no
deaths
during
the
study,
and
no
significant
differences
between
groups
or
dose­
related
trends
with
respect
to
mean
maternal
body
weight
gains
or
food
consumption
were
noted.

The
maternal
LOAEL
is
1.77
mg
ai/
kg/
day
(
2.0
mg/
kg/
day)
based
on
the
incidence
of
tremors.
The
maternal
NOAEL
is
0.88
mg
ai/
kg/
day
(
1.0
mg/
kg/
day).

Slight
developmental
toxicity
was
noted
at
1.77
mg
ai/
kg/
day
(
2.0
mg/
kg/
day)
and
was
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
20
of
50
characterized
as
an
increased
fetal
and
litter
incidence
of
"
hydroureter
without
hydronephrosis."
Although
not
statistically
significant,
the
incidence
of
hydroureter
was
double
that
of
the
vehicle
control
and
the
lower
dose
groups
(
3.55%
versus
0%
in
controls
and
low
dose
groups).
Also,
5
fetuses
from
dams
at
1.77
mg
ai/
kg/
day
(
2.0
mg/
kg/
day)
(
from
five
different
litters)
had
"
hydroureter
without
hydronephrosis,"
a
finding
that
was
not
present
in
controls
or
any
of
the
other
exposure
groups.
There
were
no
other
treatment­
related
malformations
or
variations
noted
at
any
dose
level.
There
were
no
group
differences
or
dose­
related
trends
with
respect
to
pregnancy
rates,
numbers
of
corpora
lutea,
implantation
sites
and
resorptions,
litter
sizes,
sex
ratios,
fetal
body
weights,
or
viability.
The
positive
control
gave
the
appropriate
responses
of
increased
early
resorptions,
depressed
fetal
body
weights,
external,
visceral,
and
skeletal
malformations
and
variations.

The
developmental
LOAEL
is
1.77
mg
ai/
kg/
day
(
2.0
mg/
kg/
day)
based
on
the
increased
fetal
and
litter
incidence
of
hydroureter
without
hydronephrosis.
The
developmental
NOAEL
is
0.88
mg
ai/
kg/
day
(
1.0
mg/
kg/
day).

This
developmental
toxicity
study
in
the
rat
is
classified
as
acceptable­
guideline
and
satisfies
the
guideline
requirement
for
a
developmental
toxicity
study
(
OPPTS
870.3700)
in
the
rat.

Comments:
The
original
DER
presented
fetal
incidence
data
for
hydroureter
(
with
hydronephrosis
and
without
hydronephrosis
separated).
Litter
incidence
data
were
not
provided.
The
reviewer
notes
that
litter
incidence
of
"
hydroureter
without
hydronephrosis"
is
0/
23,
0/
24,
0/
25,
and
5/
23;
the
litter
incidence
of
"
hydroureter
with
hydronephrosis"
is
3/
23,
2/
24,
2/
24
and
2/
23.
The
original
DER
concluded
based
on
fetal
incidence
data,
"
the
increased
incidence
of
hydroureter
without
associated
hydronephrosis
is
equivocal,
but
without
further
information
it
is
being
interpreted
as
indicating
a
slight
fetotoxic
effect
at
2
mg/
kg/
day."
The
reviewer
notes
that
the
litter
incidence
of
hydroureter
without
hydronephrosis
was
also
slightly
increased.
A
pilot
rat
developmental
study
(
MRID
00154482)
did
not
include
gross
necropsies,
soft
tissue
or
skeletal
examination
on
fetuses.
Hydroureter
was
not
reported
in
the
rabbit
developmental
study,
or
in
the
prenatal
developmental
toxicity
(
dietary)
study
in
rats
(
MRID
45352301).
No
historical
control
data
were
presented.

In
another
developmental
toxicity
study
(
MRID
45352301),
bifenthrin
(
95.3%
ai;
Lot/
Batch
#
PL99­
0108)
was
administered
orally
in
the
diet
to
25
female
Sprague­
Dawley
CD
rats/
group
at
dose
levels
of
0,
30,
60,
90,
or
200
ppm
(
equivalent
to
0,
2.5,
5.0,
7.4,
and
16.3
mg/
kg/
day
or
0,
2.4,
4.8,
7.1
or
15.5
mg
ai/
kg/
day
when
adjusted
for
purity)
on
gestation
days
(
GD)
6
through
20.
All
dams
were
sacrificed
on
GD
20
and
their
fetuses
were
removed
by
cesarean
and
examined.

No
animals
died
during
the
study.
When
compared
to
concurrent
controls,
no
treatment
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
21
of
50
related
changes
were
observed
in
gross
pathology,
the
number
of
corpora
lutea,
number
of
implantations,
number
of
live
and
dead
fetuses,
number
of
resorptions,
fetal
weights,
sex
ratios,
or
post­
implantation
losses.

At
200
ppm,
clinical
signs,
indicative
of
neurotoxicity,
were
observed.
These
signs
included
tremors
(
22/
25),
observed
from
days
9­
20;
hypersensitivity
to
sound
(
5/
25),
observed
from
days
18­
20;
splayed
hindlimbs
(
1/
25),
observed
from
days
15­
20;
and
piloerection
(
1/
25)
observed
at
day
19.
None
of
these
findings
was
observed
in
any
control
animal.
A
negative
trend
(
p 
0.05)
in
body
weight
gains
was
observed
during
GDs
6­
9,
15­
18,
and
18­
20
with
a
decrease
of
44,
17,
and
14%,
respectively,
at
200
ppm
relative
to
controls.
In
addition,
a
negative
trend
(
p 
0.001)
was
observed
in
adjusted
(
for
gravid
uterine
weight)
body
weight
gain
with
a
22%
decrease
at
200
ppm
when
compared
to
controls.
Food
consumption
was
decreased
at
200
ppm
at
the
beginning
(
GD
6­
9)
and
end
(
GD
18­
20)
of
treatment
( 
11­
12%,
relative
to
controls).
In
addition,
a
negative
trend
(
p 
0.05)
was
observed
during
GDs
6­
9,
9­
12,
18­
20,
and
for
the
overall
treatment
interval
(
GD
6­
20).

Dose­
dependent
(
p 
0.05
for
negative
trend)
decreases
in
food
consumption
were
observed;
however,
the
decreases
that
were
noted
at
doses
below
200
ppm
did
not
result
in
decreased
body
weight
gains
and
were
considered
not
to
be
toxicologically
important.

The
maternal
LOAEL
is
200
ppm
(
equivalent
to
16.3
mg/
kg/
day
or
15.5
mg
ai/
kg/
day)
based
on
clinical
signs
and
decreased
food
consumption,
body
weight
gains,
and
adjusted
(
for
gravid
uterine
weight)
body
weight
gains.
The
maternal
NOAEL
is
90
ppm
(
equivalent
to
7.4
mg/
kg/
day
or
7.1
mg
ai/
kg/
day).

No
treatment­
related
developmental
findings
were
noted
at
any
dose
tested.

The
developmental
toxicity
LOAEL
was
not
observed.
The
developmental
toxicity
NOAEL
is
200
ppm.

3.2.3.2
Rabbit
Developmental
Rabbit
Study
In
a
developmental
study
(
MRID
00145997),
bifenthrin
(
88.35%
ai)
in
corn
oil
was
administered
via
gavage
to
pregnant
female
New
Zealand
White
rabbits
(
20/
dose)
at
dose
levels
of
0,
2.67,
4.0,
or
8.0
mg/
kg/
day
FMC
54800
technical
(
equivalent
to
0,
2.36,
3.5,
and
7.1
mg
ai/
kg/
day)
or
with
3.0
g/
kg/
day
6­
aminonicotinamide
(
positive
control)
in
2%
carboxymethylcellulose
via
IP
injection
during
days
7­
19
of
gestation.
Maternal
toxicity
was
characterized
at
7.1
mg
ai/
kg/
day
(
8.0
mg/
kg/
day)
as
tremors
in
17/
20
rabbits
(
observed
during
days
12­
23)
and
twitching
of
the
head
and
forelimb
in
14/
20
rabbits
(
observed
during
days
13­
20).
In
addition,
one
rabbit
in
the
7.1
mg
ai/
kg/
day
group
displayed
clonic
convulsions
and
loss
of
muscle
control
during
days
17
and
18.
At
3.5
mg
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
22
of
50
ai/
kg/
day
(
4.0
mg/
kg/
day)
head
and
forelimb
twitching
was
noted
in
4/
20
rabbits
(
observed
during
days
8­
16).
There
were
no
treatment­
related
deaths
in
the
does;
however,
10
rabbits
died
during
the
study
and
9
of
these
deaths
(
including
3
vehicle
control
animals)
were
attributed
to
Pasteurella
multocida.
There
were
no
apparent
treatment­
related
differences
in
mean
body
weight
gains
in
the
does
or
pregnancy
rates;
data
excluded
those
with
infection.
There
were
no
gross
or
microscopic
findings
attributable
to
exposure
to
the
test
material.

The
maternal
LOAEL
is
3.5
mg
ai/
kg/
day
(
4.0
mg/
kg/
day)
based
on
the
treatment­
related
incidence
of
head
and
forelimb
twitching.
The
maternal
NOAEL
is
2.36
mg
ai/
kg/
day
(
2.67
mg/
kg/
day).
There
was
no
developmental
toxicity
demonstrated
at
any
dose
level.

There
were
no
treatment­
related
effects
on
the
number
of
live
fetuses,
fetal
weights,
implantations,
resorptions,
external,
visceral
or
skeletal
malformations
and
variations.
The
positive
control
gave
the
appropriate
responses
of
increased
early
resorptions,
reduced
number
of
live
fetuses,
increased
external,
visceral,
and
skeletal
malformations
and
variations.

A
developmental
LOAEL
was
not
observed.
The
developmental
NOAEL
is
 
7.1
mg
ai/
kg/
day
(
8.0
mg/
kg/
day).

3.2.4
Reproductive
Toxicity
Study
(
Rat)

In
a
2­
generation
study
(
MRID
00157225),
liquified
bifenthrin
(
88.35%
ai)
mixed
with
acetone
was
administered
in
the
diet
to
TAC(
SD)
fBR
rats
(
25/
sex/
dose)
at
dose
levels
of
0,
30,
60,
or
100
ppm
as
FMC
54800
technical
(
approximately
equivalent
to
0,
1.5,
3.0
and
5.0
mg/
kg/
day).
P
generation
females
at
100
ppm
had
lower
mean
body
weights
( 
4%,
p<
0.05)
at
week
17
(
after
gestation
and
lactation),
significantly
lower
body
weights
during
the
first
lactation
(
days
7
and
14)
period;
and
lower
body
weight
gains
during
the
second
gestation
and
lactation
periods
(
statistically
significant
only
on
lactation
day
14,

 
5%
body
weight
and
 
34%
for
body
weight
gain,
p<
0.01).
There
was
no
correlation
between
lower
body
weight
and
frequency
of
tremors.
Lower
body
weights
in
females
at
60
ppm
(
although
not
statistically
significant)
frequently
paralleled
body
weight
depression
at
100
ppm.
There
were
no
clinical
signs
or
effects
on
body
weight
at
30
ppm.
There
were
no
significant
differences
in
mean
body
weights
between
treated
F1animals
and
controls.
In
the
high­
dose
P
generation
females,
there
was
a
statistically
significant
increase
in
absolute
and
relative
brain
weights.
Mean
absolute
ovary
weights
were
slightly
decreased
( 
9%,
p<
0.05
or
 
12%,
p<
0.01)
at
60
and
100
ppm,
respectively,
in
the
F1
parental
generation;
however,
ovary­
to
body­
weight
ratios
were
unaffected.
In
the
100
ppm
group
F1b
female
progeny,
absolute
adrenal
and
heart
weights
were
statistically
elevated
compared
to
control
values.
Significantly
elevated
absolute
ovary
and
ovary/
brain
weights
were
also
observed
in
these
animals.
There
were
no
treatment­
related
gross
or
microscopic
findings
in
either
adults
or
progeny.
In
either
the
P
or
F1
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
23
of
50
generations,
there
were
no
treatment­
related
effects
on
reproductive
parameters
(
mating,
male
fertility,
female
fertility
and
gestation
indices),
and
there
were
no
treatment­
related
gross
or
microscopic
findings
in
either
sex.

The
parental
LOAEL
is
100
ppm
(
5.0
mg/
kg/
day)
based
on
the
incidence
of
tremors
and
marginally
lower
body
weights
in
P
and
F1
generation
females
during
gestation
and
lactation.
The
parental
NOAEL
is
60
ppm
(
3.0
mg/
kg/
day).
A
reproductive
and
offspring
LOAEL
was
not
observed.
The
reproductive
and
offspring
NOAEL
is
100
ppm
(
5.0
mg/
kg/
day).

Comments:
The
original
DER
identified
the
60
ppm
dose
as
a
LOAEL
based
on
decreased
absolute
ovarian
weight;
however,
the
DER
also
indicated
that
the
decreased
F1
absolute
ovarian
weight
is
"
equivocal
as
it
was
only
observed
in
F1
adult
females
and
not
in
F1b
or
F2b
weanlings),"
and
"
when
ovary­
to­
body
weight
ratios
for
F1
females
are
examined,
none
of
the
FMC
54800
exposed
groups
are
statistically
different
from
controls
for
this
parameter."
The
reviewer
agrees,
and
notes
the
lack
of
histopathology
effects.
The
reviewer
considers
the
60
ppm
dose
level
as
a
NOAEL.

A
range­
finding
study
summarized
in
the
DER
indicates
that
excessive
fetotoxicity
occurred
at
10
mg/
kg/
day
(
all
pups
from
2
of
the
4
litters
at
10
mg/
kg/
day
died
within
14
days
of
birth)
and
body
weight
gains
were
decreased
during
lactation
at
2.5,
5,
and
10
mg/
kg/
day.

3.2.5
Additional
Information
from
Literature
Sources
None.

3.2.6
Pre­
and/
or
Postnatal
Toxicity
The
HIARC
concluded
that
there
is
not
a
concern
for
pre­
and/
or
postnatal
toxicity
resulting
from
exposure
to
bifenthrin.

3.2.6.1
Determination
of
Susceptibility
Based
on
the
results
in
a
developmental
toxicity
studies
in
rats
and
rabbits,
there
was
no
quantitative
or
qualitative
evidence
of
increased
susceptibility
of
rat
or
rabbit
fetuses
to
in
utero
exposure
to
bifenthrin.

Based
on
the
results
in
a
2­
generation
reproduction
study
in
rats,
there
was
no
quantitative
or
qualitative
evidence
of
increased
susceptibility
of
neonates
(
as
compared
to
adults)
to
bifenthrin.

3.2.6.2
Degree
of
Concern
Analysis
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
24
of
50
There
are
no
concerns
or
residual
uncertainties
for
pre
and/
or
post­
natal
toxicity
following
exposure
to
bifenthrin.

Based
upon
the
above­
described
data,
no
special
FQPA
safety
factor
is
needed
(
i.
e.
1X)
since
there
are
no
residual
uncertainties
for
pre
and/
or
post
natal
toxicity.

The
Special
FQPA
Safety
Factor
recommended
by
the
HIARC
assumes
that
the
exposure
databases
(
dietary
food,
drinking
water,
and
residential)
are
complete
and
that
the
risk
assessment
for
each
potential
exposure
scenario
includes
all
metabolites
and/
or
degradates
of
concern
and
does
not
underestimate
the
potential
risk
for
infants
and
children.

3.2.7
Recommendation
for
a
DNT
Study
The
HIARC
concluded
that
there
is
a
concern
for
DNT
resulting
from
exposure
to
bifenthrin.
A
DNT
study
has
been
submitted
and
is
under
review.
The
UFDB
may
change
pending
the
results
of
the
recently
submitted
DNT
study.

On
January
22,
2003,
based
on
the
weight
of
evidence
presented,
the
HIARC
reaffirmed
the
previous
conclusion
that
a
DNT
(
DNT)
study
conducted
with
bifenthrin
in
rats
is
required.
HIARC
determined
that
a
10X
database
UF
(
UFDB)
is
needed
to
account
for
the
lack
of
the
DNT
when
assessing
acute
(
single
dose)
exposure
scenarios
since
the
available
(
acute)
data
provide
no
basis
to
support
reduction
or
removal
of
the
default
10X
factor.
The
following
points
were
considered
in
this
determination:

°
It
is
assumed
that
the
DNT
study
will
be
conducted
at
dose
levels
similar
to
those
used
in
the
rat
reproduction
study
with
bifenthrin
wherein
the
offspring
NOAEL
was
5.0
mg/
kg/
day
(
no
effects
were
observed
in
offspring
at
the
highest
dose
tested).
But
that
the
DNT
would
not
be
conducted
at
dose
levels
higher
than
10
mg/
kg/
day
since
a
range­
finding
study
indicates
excessive
fetotoxicity
occurred
at
this
dose
(
all
pups
from
2
of
the
4
litters
at
10
mg/
kg/
day
died
within
14
days
of
birth).

°
It
is
likely
that
the
results
of
the
DNT
study
will
impact
the
currently
selected
acute
regulatory
dose
since
the
NOAEL
used
to
establish
the
acute
Reference
dose
for
dietary
risk
assessment
(
33
mg/
kg/
day)
is
higher
(
more
than
5­
fold)
than
the
offspring
NOAEL
in
the
rat
reproduction
study
conducted
with
Bifenthrin
(
5.0
mg/
kg/
day).

Given
these
circumstances,
HIARC
does
not
have
sufficient
reliable
data
justifying
selection
of
an
additional
safety
factor
for
the
protection
of
infants
and
children
lower
than
the
default
value
of
10X
for
single
dose
exposure
scenarios.
Therefore,
a
UFDB
of
10X
will
be
applied
to
single
dose
exposure
scenarios
(
i.
e.,
acute
RfD)
to
account
for
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
25
of
50
the
lack
of
the
DNT
study
with
bifenthrin.

HIARC
further
determined
that
for
repeated
dose
exposure
scenarios
a
3X
database
UF
(
UFDB)
is
adequate
to
account
for
the
lack
of
the
DNT
based
on
the
following
considerations:

°
As
stated
above,
the
DNT
study
will
likely
be
conducted
at
dose
levels
similar
to
the
rat
reproduction
study.
°
The
results
of
the
DNT
study
are
not
expected
to
impact
the
current
regulatory
doses
selected
for
repeated
exposure
scenarios
since
the
NOAELs
used
for
these
risk
assessment
endpoints
(
e.
g.,
1.3
mg/
kg/
day
for
chronic
RfD)
are
approximately
5­
fold
lower
than
the
offspring
NOAEL
(
5.0
mg/
kg/
day)
in
the
rat
reproduction
study
conducted
with
bifenthrin.

Although
the
results
of
the
DNT
are
not
expected
to
impact
the
current
regulatory
dose
given
the
3­
fold
difference
observed
in
the
rat
and
dog
studies,
HIARC
does
not
have
sufficient
reliable
data
to
apply
no
additional
safety
factor.
Rather,
HIARC
believes
that
the
5X
difference
between
the
offspring
NOAEL
in
the
rat
reproduction
study
and
the
NOAELs
used
for
risk
assessment
endpoints
provides
reliable
data
supporting
a
3X.
The
use
of
a
3X
provides
roughly
a
10­
fold
difference
between
the
NOAEL
associated
with
the
identified
effects
in
the
rat
necessitating
the
DNT
study
and
the
NOAELs
used
for
setting
regulatory
doses.

Therefore,
a
UFDB
of
3X
will
be
applied
to
repeated
dose
exposure
scenarios
(
i.
e.,
chronic
RfD,
short­
and
intermediate­
term
incidental
oral,
and
short­,
intermediate­,
and
long­
term
dermal
and
inhalation)
to
account
for
the
lack
of
the
DNT
study
with
bifenthrin.

3.3
Hazard
Identification
and
Toxicity
Endpoint
Selection
The
strengths
and
weaknesses
of
the
bifenthrin
toxicology
database
were
considered
during
the
process
of
toxicity
endpoint
and
dose
selection.
The
selected
toxicity
endpoints
are
summarized
in
Table
3.5.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
26
of
50
Table
3.3
Summary
of
Toxicological
Doses
and
Endpoints
for
Bifenthrin
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
FQPA
SF1
and
Level
of
Concern
for
Risk
Assessment
Study
and
Toxicological
Effects
Acute
Dietarygeneral
population,
including
infants
and
children
NOAEL
=
32.8
mg
ai/
kg
UF
=
1000
Acute
RfD
=
0.033
mg/
kg/
day
FQPA
SF
=
1X
aPAD
=
acute
RfD
FQPA
SF
=
0.033
mg/
kg/
day
Acute
neurotoxicity
study
in
rats.
LOAEL
=
70.3
mg/
kg/
day
based
on
observations
of
mortality
(
females
only),
clinical
and
FOB
findings
and
differences
in
motor
activity.

Chronic
Dietarygeneral
population,
including
infants
and
children
NOAEL
=
1.3
mg
ai/
kg/
day
UF
=
300
Chronic
RfD
=
0.004
mg/
kg/
day
FQPA
SF
=
1X
cPAD
=
cRfD
FQPA
SF
=
0.004
mg/
kg/
day
1­
year
oral
toxicity
in
dogs.
LOAEL
=
2.7
mg/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
in
both
sexes.

Short­
Term
(
1­
30
days)
Incidental
Oral
NOAEL=
2.21
mg
ai/
kg/
day
UF
=
300
MOE=
300
Residential
MOE
=
300
90­
day
oral
toxicity
study
in
dogs.
LOAEL
=
4.42
mg/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
in
both
sexes.

Intermediate­
Term
(
1­
6
months)
Incidental
Oral
NOAEL=
2.21
mg
ai/
kg/
day
UF
=
300
MOE=
300
Residential
MOE
=
300
90­
day
oral
toxicity
study
in
dogs.
LOAEL
=
4.42
mg/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
in
both
sexes.

Short­
Term
(
1­
30
days)
Dermal
Dermal
NOAEL
=
47
mg/
kg/
day
Residential
MOE
=
300
Occupational
MOE
=
100
21­
day
dermal
study
in
rats.

LOAEL
=
93
mg/
kg/
day
based
on
observations
of
clinical
signs
(
staggered
gait
and
exaggerated
hindlimb
reflex).

Intermediate­
Term
(
1­
6
months)
Dermal
Dermal
NOAEL
=
47
mg/
kg/
day
Residential
MOE
=
300
Occupational
MOE
=
100
21­
day
dermal
study
in
rats.

LOAEL
=
93
mg/
kg/
day
based
on
observations
of
clinical
signs
(
staggered
gait
and
exaggerated
hindlimb
reflex).

Long­
Term
(>
6
months)
Dermal
Dermal
NOAEL
=
47
mg/
kg/
day
Residential
MOE
=
300
Occupational
MOE
=
100
21­
day
dermal
study
in
rats.

LOAEL
=
93
mg/
kg/
day
based
on
observations
of
clinical
signs
(
staggered
gait
and
exaggerated
hindlimb
reflex).

Short­
Term
(
1­
30
days)
Inhalation
NOAEL=
2.21
mg
ai/
kg/
day
UF
=
300
Residential
MOE
=
300
Occupational
MOE
=
100
1­
year
oral
toxicity
in
dogs.
LOAEL
=
2.7
mg/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
27
of
50
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
FQPA
SF1
and
Level
of
Concern
for
Risk
Assessment
Study
and
Toxicological
Effects
MOE=
300
in
both
sexes.

Intermediate­
Term
(
1­
6
months)
Inhalation
NOAEL=
2.21
mg
ai/
kg/
day
UF
=
300
MOE=
300
Residential
MOE
=
300
Occupational
MOE
=
100
1­
year
oral
toxicity
in
dogs.
LOAEL
=
2.7
mg
ai/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
in
both
sexes.

Long­
Term
(>
6
months)

Inhalation
NOAEL=
2.21
mg
ai/
kg/
day
UF
=
300
MOE=
300
Residential
MOE
=
300
Occupational
MOE
=
100
1­
year
oral
toxicity
in
dogs.
LOAEL
=
2.7
mg/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
in
both
sexes.

Cancer
(
oral,
dermal,
inhalation)
Classification:
Category
C
(
possible
human
carcinogen).
No
Q1*
has
been
derived.
RfD
approach
recommended
for
cancer
assessment.

UF
=
uncertainty
factor,
FQPA
SF
=
Special
FQPA
Safety
Factor,
NOAEL
=
no
observed
adverse
effect
level,
LOAEL
=
lowest
observed
adverse
effect
level,
RfD
=
reference
dose
(
a
=
acute,
c
=
chronic),
PAD
=
population
adjusted
dose,
MOE
=
margin
of
exposure,
LOC
=
level
of
concern,
N/
A
=
Not
Applicable
1
Refer
to
Section
3.4
3.3.1
Acute
Reference
Dose
(
aRfD)
­
Females
age
13­
49
HIARC
determined
that
no
appropriate
acute
dietary
endpoint
was
available
to
quantify
risk
to
females
13­
50
years
of
age
from
a
single­
dose
administration
of
bifenthrin.

A
developmental
toxicity
study
in
rats
(
gavage)
with
a
developmental
NOAEL
of
0.88
mg
ai/
kg/
day
(
1.0
mg/
kg/
day)
based
on
the
increased
fetal
and
litter
incidence
of
hydroureter
without
hydronephrosis
seen
at
the
LOAEL
of
1.77
mg
ai/
kg/
day
(
2.0
mg/
kg/
day)
was
considered
as
an
endpoint
for
aRfD
for
females
age
13­
49.
However,
this
evidence
was
considered
as
equivocal
since
the
litter
incidence
of
"
hydroureter
without
hydronephrosis"
is
0/
23,
0/
24,
0/
25,
and
5/
23;
the
litter
incidence
of
"
hydroureter
with
hydronephrosis"
is
3/
23,
2/
24,
2/
24
and
2/
23.
In
addition,
this
effect
was
not
observed
in
a
dietary
developmental
toxicity
study
in
rats
using
the
same
strain
of
rats.
Therefore,
HIARC
concluded
that
the
endpoint
(
hydroureter/
hydronephrosis)
is
not
appropriate
for
this
risk
assessment.

3.3.2
Acute
Reference
Dose
(
aRfD)
­
General
Population
Acute
dietary
endpoints
were
available
to
quantify
risk
to
the
general
population,
including
infants
and
children.
For
this
scenario,
an
acute
reference
dose
(
aRFD)
of
0.033
mg/
kg/
day
was
determined
on
the
basis
of
an
acute
neurotoxicity
study
in
rats
and
the
application
of
an
UF
of
1000
(
10x
for
interspecies
extrapolation,
10x
for
intraspecies
variation,
and
10x
for
incomplete
database
for
lack
of
a
DNT
study).
The
NOAEL
in
this
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
28
of
50
study
was
32.8
mg
ai/
kg/
day
and
the
LOAEL
was
70.3
mg
ai/
kg/
day
based
on
mortality
(
females),
clinical
and
FOB
findings
and
differences
in
motor
activity.
Although
a
lower
NOAEL
for
an
effect
(
i.
e.,
tremors
in
dams)
associated
with
a
single
dose
exposure
was
observed
in
a
developmental
gavage
study,
the
vehicle
(
corn
oil)
used
in
this
study
enhanced
the
toxicity
of
bifenthrin.
There
is
evidence
that,
in
the
case
for
bifenthrin,
corn
oil
can
enhance
its
toxicity.
This
evidence
is
based
on
the
results
of
comparative
studies
of
the
acute
oral
LD50
of
bifenthrin
following
oral
gavage
as
either
a
corn
oil
vehicle
or
as
an
undiluted
technical
material
to
rats.
These
comparative
studies
demonstrate
increased
lethality
from
bifenthrin
exposure
in
a
corn
oil
vehicle.
In
the
acute
neurotoxicity
study
in
rats,
bifenthrin
was
administered
undiluted
by
gavage,
making
this
study
more
suitable
than
the
developmental
gavage
study
(
with
corn
oil
as
vehicle)
for
risk
assessment
purposes.
Therefore,
the
acute
neurotoxicity
study
was
selected
for
the
acute
reference
dose,
and
the
aRfD
is
0.033
mg/
kg/
day.

3.3.3
Chronic
Reference
Dose
(
cRfD)

A
cRfD
of
0.004
mg/
kg/
day
was
determined
on
the
basis
of
the
one­
year
oral
study
in
dogs
and
the
application
of
an
UF
of
300
(
10x
for
interspecies
extrapolation,
10x
for
intraspecies
variation,
and
3x
for
incomplete
database
for
lack
of
a
DNT
study).
The
NOAEL
in
this
study
was
1.3
mg
ai/
kg/
day
and
the
LOAEL
was
2.7
mg
ai/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
in
both
sexes.

3.3.4
Incidental
Oral
Exposure
(
Short­
and
Intermediate­
Term)

A
NOAEL
of
2.21
mg
ai/
kg/
day
was
selected
from
the
90­
day
oral
study
in
dogs,
and
used
for
short­
and
intermediate­
term
incidental
oral
and
short­
and
intermediate­
term
inhalation
risk
assessments.
This
NOAEL
was
based
on
observations
of
increased
incidence
of
tremors
in
males
and
females
at
the
LOAEL
of
4.42
mg
ai/
kg/
day.
The
HIARC
concluded
that
the
selected
dose/
endpoint
is
appropriate
for
the
population
and
durations
of
concern.
For
the
inhalation
scenarios,
an
inhalation
absorption
factor
of
100%
(
default
value
assuming
equivalent
inhalation
and
oral
absorption)
was
used
for
route­
to­
route
extrapolation.

3.3.5
Dermal
Absorption
Several
dermal
absorption
studies
on
bifenthrin
were
available;
each
study
was
considered
acceptable
for
regulatory
purposes
when
taken
in
conjunction
with
the
other
studies.
The
HIARC
recommended
a
dermal
absorption
rate
of
25%
based
on
the
weight­
of
theevidence
available
for
structurally
related
pyrethroids.
However,
since
a
dermal
toxicity
study
was
used
for
the
assessment
of
short­
and
intermediate­
term
dermal
risk,
the
dermal
absorption
factor
was
not
used.

3.3.6
Dermal
Exposure
(
Short­
and
Intermediate­
Term)
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
29
of
50
A
NOAEL
of
47
mg/
kg/
day
was
selected
from
the
21­
day
dermal
study
in
rats.
The
LOAEL
of
93
mg/
kg/
day
was
based
on
observations
of
clinical
signs
(
staggered
gait
and
exaggerated
hindlimb
flexion).
The
HIARC
determined
that
the
dermal
toxicity
study
is
appropriate
for
short­,
intermediate­
and
long­
term
dermal
exposures
and
durations
because,
besides
route
specificity,
the
subchronic
and
chronic
oral
toxicity
studies
in
dogs
and
rats
demonstrate
neurotoxicity
of
similar
magnitude.
Since
a
dermal
toxicity
study
is
selected
for
dermal
risk
assessment,
a
dermal
absorption
factor
is
not
required.

3.3.7
Inhalation
Exposure
(
Short
and
Intermediate­
Term)

A
NOAEL
of
2.21
mg/
kg/
day
was
selected
from
the
90­
day
oral
study
in
dogs,
and
used
for
short­
and
intermediate­
term
inhalation
risk
assessments.
This
NOAEL
was
based
on
observations
of
increased
incidence
of
tremors
in
males
and
females
at
the
LOAEL
of
4.42
mg/
kg/
day.
The
HIARC
concluded
that
the
selected
dose/
endpoint
is
appropriate
for
the
population
and
durations
of
concern.
An
inhalation
absorption
factor
of
100%
(
default
value
assuming
equivalent
inhalation
and
oral
absorption)
was
used
for
route­
to­
route
extrapolation.

The
results
of
the
one­
year
oral
dog
study
were
selected
for
the
long­
term
inhalation
risk
assessment.
The
NOAEL
in
this
study
was
1.3
mg/
kg/
day
and
the
LOAEL
was
2.7
mg/
kg/
day
based
on
observations
of
increased
incidence
of
tremors
in
both
sexes.
An
inhalation
absorption
factor
of
100%
(
default
value
assuming
equivalent
inhalation
and
oral
absorption)
was
used
for
route­
to­
route
extrapolation.

3.3.8
Level
of
Concern
for
Margin
of
Exposure
The
target
MOEs
for
occupational
and
residential
exposure
risk
assessments
are
as
follows:
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
30
of
50
Duration
Route
Short­
Term
(
1­
30
days)
Intermediate­
Term
(
1
­
6
Months)
Long­
Term
(>
6
Months)

Occupational
(
Worker)
Exposure
Dermal
100a
100
100
Inhalation
100
100
100
Residential
(
Non­
Dietary)
Exposure
Oral
300
300
300
Dermal
300
300
300
Inhalation
300
300
300
a
based
on
the
conventional
UF
of
100X
(
10X
for
interspecies
extrapolation
and
10X
for
intraspecies
variation)

3.3.9
Recommendation
for
Aggregate
Exposure
Risk
Assessments
The
toxicity
endpoints
selected
for
these
routes
of
exposure
may
be
aggregated
as
follows:
for
short­,
intermediate­
and
long­
term
aggregate
exposure
risk
assessments,
the
oral,
dermal
and
inhalation
(
oral
equivalent)
routes
can
be
combined
because
of
the
common
toxicity
endpoints
(
clinical
signs
of
neurotoxicity)
via
these
routes.

3.3.10
Classification
of
Carcinogenic
Potential
There
was
no
conclusive
evidence
of
carcinogenic
potential
of
bifenthrin
in
the
rat.
A
mouse
oncogenicity
study
provided
some
evidence
for
the
carcinogenic
potential
of
bifenthrin
in
this
species.
In
the
mouse
oncogenicity
study,
high­
dose
males
showed
a
highly
significant
increased
incidence
of
urinary
bladder
tumors.
Other
findings
in
the
mouse
study
included
a
dose­
related
trend
of
increased
combined
incidences
of
adenoma
and
adenocarcinoma
of
the
liver
(
males
only),
and
increased
incidences
of
bronchioalveolar
adenomas
and
adenocarcinomas
of
the
lung
in
females
at
50,
200
and
600
ppm
(
but
not
500
ppm)
relative
to
their
controls.
The
CPRC
has
characterized
bifenthrin
as
Category
C
(
possible
human
carcinogen)
primarily
on
the
basis
of
the
mouse
study.
Other
findings
in
the
mouse
study
included
a
dose­
related
trend
of
increased
combined
incidences
of
adenoma
and
adenocarcinoma
of
the
liver
(
males
only),
and
increased
incidences
of
bronchioalveolar
adenomas
and
adenocarcinomas
of
the
lung
in
females
at
some,
but
not
all,
doses
relative
to
their
controls.
The
CARC
(
1992)
recommended
that
for
the
purpose
of
risk
characterization,
the
reference
dose
(
RfD)
approach
should
be
used
for
quantification
of
human
risk.

3.4
Endocrine
disruption
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
31
of
50
EPA
is
required
under
the
Federal
Food,
Drug,
and
Cosmetic
Act
(
FFDCA),
as
amended
by
FQPA,
to
develop
a
screening
program
to
determine
whether
certain
substances
(
including
all
pesticide
active
and
other
ingredients)
"
may
have
an
effect
in
humans
that
is
similar
to
an
effect
produced
by
a
naturally
occurring
estrogen,
or
other
such
endocrine
effects
as
the
Administrator
may
designate."
Following
recommendations
of
its
Endocrine
Disruptor
and
Testing
Advisory
Committee
(
EDSTAC),
EPA
determined
that
there
was
a
scientific
basis
for
including,
as
part
of
the
program,
the
androgen
and
thyroid
hormone
systems,
in
addition
to
the
estrogen
hormone
system.
EPA
also
adopted
EDSTAC=
s
recommendation
that
the
Program
include
evaluations
of
potential
effects
in
wildlife.
For
pesticide
chemicals,
EPA
will
use
the
Federal
Insecticide,
Fungicide,
and
Rodenticide
Act
(
FIFRA)
and,
to
the
extent
that
effects
in
wildlife
may
help
determine
whether
a
substance
may
have
an
effect
in
humans,
FFDCA
authority
to
require
the
wildlife
evaluations.
As
the
science
develops
and
resources
allow,
screening
of
additional
hormone
systems
may
be
added
to
the
Endocrine
Disruptor
Screening
Program
(
EDSP).
Bifenthrin
database
did
not
indicate
any
endocrine
mediated
effects.
When
additional
appropriate
screening
and/
or
testing
protocols
being
considered
under
the
Agency's
EDSP
have
been
developed,
bifenthrin
may
be
subjected
to
further
screening
and/
or
testing
to
better
characterize
effects
related
to
endocrine
disruption.

4.0
Dietary
Exposure/
Risk
Characterization
4.1
Pesticide
Metabolism
and
Environmental
Degradation
4.1.1
Metabolism
in
Primary
Crops
and
Livestock
4.1.1.1
Metabolism
in
Primary
Crops
Bifenthrin
TRED,
S.
Levy,
21­
AUG­
2002;
DP#
283808
45794202.
der
The
nature
of
bifenthrin
residues
in
plants
is
adequately
understood
based
on
the
available
metabolism
studies
on
corn,
cotton,
and
apple.
HED
previously
determined
that
for
purposes
of
tolerance
expression
and
risk
assessment,
the
residue
of
concern
in
cotton
and
apple
commodities
is
bifenthrin
per
se
(
Memos,
M.
Flood,
24­
DEC­
1987
and
N.
Dodd,
02­
JUL­
1987).
After
re­
examining
the
cotton
and
apple
metabolism
data
and
additional
corn
metabolism
data,
the
HED
Metabolism
Committee
(
Memo,
M.
Flood,
23­
JUL­
1993)
reaffirmed
that
the
residue
of
concern
in
plant
commodities
is
bifenthrin
per
se.

In
conjunction
with
the
petition
for
use
on
tuberous
and
corm
vegetables,
IR­
4
has
submitted
an
additional
metabolism
study
on
potatoes
reflecting
both
soil
and
foliar
applications
of
[
14C]
bifenthrin.
The
potato
study
is
adequate
and
the
results
from
the
metabolism
study
support
HED's
previous
determination
that
the
residue
of
concern
is
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
32
of
50
bifenthrin
per
se.

4.1.1.2
Metabolism
in
Livestock
Bifenthrin
TRED,
S.
Levy,
21­
AUG­
2002;
DP#
283808
Adequate
ruminant
and
poultry
metabolism
studies
are
available
depicting
the
metabolism
of
bifenthrin
radiolabeled
in
either
the
phenyl
or
cyclopropyl
ring.
Based
on
these
data,
the
HED
Metabolism
Committee
(
M.
Flood,
8/
2/
93)
concluded
that
the
residue
of
concern
in
livestock
commodities
is
bifenthrin
per
se.

4.1.2
Metabolism
in
Rotational
Crops
Bifenthrin
TRED,
S.
Levy,
21­
AUG­
2002;
DP#
283808
Adequate
confined
and
field
rotational
crop
studies
are
available.
Based
on
the
confined
study,
HED
has
concluded
that
the
residue
of
concern
in
rotational
crops
is
the
parent
compound
only.

4.1.3
Analytical
Methodology
Adequate
gas
chromatography
(
GC)/
electron­
capture
detection
(
ECD)
methods
are
available
for
enforcing
tolerances
of
bifenthrin
in
plant
and
livestock
commodities.
The
available
methods
for
plant
commodities
generally
involve
extraction
of
the
sample
with
acetone,
partitioning
with
hexane,
purification
using
a
Florisil
column,
and
analysis
of
residues
by
GC/
ECD.
The
limit
of
quantitation
(
LOQ)
for
these
methods
is
0.05
ppm.
Samples
from
the
current
field
trials
and
the
potato
processing
study
were
analyzed
using
methods
that
are
modifications
to
one
of
the
current
enforcement
methods
(
P­
2550
M),
with
variations
in
extraction
solvents
and
detection
methods.
Residues
of
bifenthrin
in/
on
mustard
greens
and
cilantro
(
leaves
and
seeds)
were
determined
using
a
GC/
ECD
method
(
FMC
Report
P­
2132).
For
this
method,
residues
are
extracted
with
hexane,
concentrated,
and
cleaned
up
using
a
Florisil
column,
then
analyzed
by
GC/
ECD.
Residues
in/
on
potato
fractions
and
dried
beans
and
peas
were
determined
using
a
GC/
mass­
selective
detection
(
MSD)
method
(
FMC
Report
P­
3426).
For
this
method,
residues
are
extracted
with
acetone,
concentrated,
and
purified
by
silica­
gel
solid­
phase
extraction
(
SPE).
The
residues
are
then
analyzed
by
GC/
MSD,
using
the
m/
z
181
ion
for
quantitation.
Residues
in/
on
green
tobacco
were
determined
using
a
related
GC/
MSD
method
(
FMC
Report
P­
3457).
For
this
method,
residues
are
extracted
with
acetone/
water,
partitioned
into
hexane,
and
cleaned
up
with
a
SPE
column,
and
analyzed
by
GC/
MSD.
For
each
of
the
above
methods,
the
LOQ
for
bifenthrin
is
0.05
ppm,
and
the
reported
limit
of
detection
(
LOD)
is
0.01
ppm.
Each
of
these
methods
was
adequately
validated
in
conjunction
with
analysis
of
samples
from
the
field
trials
or
processing
study.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
33
of
50
4.1.4
Environmental
Degradation
Tier
I
Estimated
Environmental
Concentrations
of
Bifenthrin
for
the
Use
in
the
Human
Health
Risk
Assessment.
02/
07/
2006.
J.
Melendez
The
environmental
fate
database
for
bifenthrin
is
complete
enough
to
characterize
drinking
water
exposure.
The
submitted
data
indicate
that
bifenthrin
is
relatively
persistent
under
both
laboratory
and
field
conditions.
Bifenthrin
is
relatively
immobile
in
four
soils
tested.
Due
to
its
low
mobility,
bifenthrin
is
not
likely
to
reach
subsurface
soil
environments
(
lower
microbial
activity)
or
ground
waters.
Various
terrestrial
field
dissipation
studies
confirm
that
bifenthrin
remains
mostly
in
the
upper
soil
level.
Due
to
its
low
solubility
and
high
level
of
binding
it
appears
that
bifenthrin
would
remain
bound
to
the
soils
during
runoff
events
and
it
may
reach
surface
waters
if
the
run­
off
event
is
accompanied
by
erosion.

The
HED
Metabolism
Assessment
Review
Committee
(
MARC)
concluded
that
the
parent
compound,
bifenthrin
per
se,
should
be
the
residue
of
concern
for
drinking
water
risk
assessment
based
on
its
persistence
and
the
absence
of
major
degradates
in
laboratory
studies
(
HED
Doc.
No.
0050887).

4.1.5
Food
Residue
Profile
The
field
trials
on
potatoes,
mustard
greens,
dried
beans
and
peas,
cilantro,
and
tobacco
are
adequate.
An
adequate
number
of
trials
were
conducted
reflecting
the
proposed
use
patterns
in
the
appropriate
geographic
regions,
and
the
appropriate
commodities
were
collected
at
the
proposed
PHIs.
Samples
were
analyzed
using
adequate
analytical
methods,
and
the
sample
storage
intervals
are
supported
by
the
available
storage
stability
data.

Following
an
at­
planting
soil
application
and
two
foliar
applications
of
bifenthrin
at
1x
the
proposed
rate,
residues
were
<
0.05
ppm
(<
LOQ)
in/
on
all
potatoes
harvested
at
21
days
after
the
final
treatment
(
DAT).
Residues
on
mustard
greens
harvested
6­
7
DAT
were
<
0.05­
2.05
ppm
following
four
foliar
applications
of
bifenthrin
(
EC)
totaling
~
0.4
lb
ai/
A
(
1x).
In
the
dried
bean
and
pea
field
trials,
residues
on
dried
beans
harvested
13­
15
DAT
were
<
0.05­
0.10
ppm
following
three
foliar
applications
of
bifenthrin
(
EC)
totaling
0.3
lb
ai/
A
(
1x),
and
residues
on
dried
peas
harvested
14­
15
DAT
were
<
0.05
ppm
following
two
foliar
applications
of
bifenthrin
(
EC)
totaling
0.2
lb
ai/
A
(
1x).
Following
five
foliar
applications
of
bifenthrin
(
EC)
to
cilantro
totaling
~
0.5
lb
ai/
A
(
1x),
residues
at
3
DAT
were
1.98­
4.83
ppm
in/
on
fresh
leaves,
14.93­
16.25
ppm
in/
on
dried
leaves,
and
3.66­
3.69
ppm
in/
on
seeds.
In
the
tobacco
field
trials,
residues
of
bifenthrin
were
<
0.05
ppm
in/
on
all
green
tobacco
samples
harvested
at
normal
maturity
following
either
a
preplant
or
attransplanting
application
of
bifentrhin
(
EC
or
G)
at
0.1
lb
ai/
A
and
a
single
foliar
application
of
bifenthrin
(
EC)
at
0.05
or
0.10
lb
ai/
A
(
1x).
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
34
of
50
The
available
potato
processing
study
is
adequate.
Because
bifenthrin
residues
were
<
LOQ
(<
0.05
ppm)
in
all
samples
from
the
potato
field
trials
and
in
potato
tubers
and
all
processed
fractions
from
the
processing
study
conducted
at
a
3x
rate,
HED
concludes
that
residues
of
bifenthrin
in
wet
peel
are
unlikely
to
exceed
the
LOQ
when
bifenthrin
is
applied
at
a
1x
rate.
Therefore,
a
separate
tolerance
will
be
not
be
required
for
residues
in/
on
processed
potato
fractions.
In
addition,
a
comparison
of
residues
in/
on
fresh
and
dried
cilantro
leaves
indicates
that
there
is
a
5.7x
processing
factor
for
dried
cilantro
leaves.
Based
on
highest­
average
field­
trial
(
HAFT)
residues
of
3.96
ppm
in/
on
fresh
leaves,
the
maximum
expected
residues
in/
on
dried
cilantro
leaves
would
be
22.6
ppm.

The
proposed
tolerances
for
plant
commodities
will
not
have
any
impact
on
the
current
tolerances
for
livestock
commodities.
The
only
proposed
crop
use
with
any
regulated
livestock
feedstuffs
is
potato
(
processed
potato
waste
and
culls),
and
the
addition
of
these
commodities
to
livestock
diets
will
not
increase
the
dietary
exposure
of
livestock
calculated
in
the
Bifenthrin
Tolerance
Reassessment
Eligibility
Decision
(
TRED)
(
S.
Levy,
22­
AUG­
2002;
DP#
283808).

Adequate
confined
and
field
rotational
crop
studies
are
available
to
support
the
proposed
uses.
Based
on
the
results
of
these
rotational
crop
studies,
HED
concludes
that
the
current
rotational
crop
plant­
back
interval
is
acceptable
and
that
tolerances
for
rotated
crops
are
not
necessary.

4.1.5.1
Tolerance
Summary
The
tolerances
proposed
by
the
registrants
in
the
current
vegetable
petitions
are
listed
below
in
Table
5.1.5.1,
along
with
HED's
recommended
tolerance
levels.
The
appropriate
tolerance
levels
were
calculated
using
the
methodology
formulated
by
the
NAFTA
MRL/
Tolerance
Harmonization
Workgroup
for
calculating
statistically­
based
pesticide
tolerances
for
plant
commodities
based
on
field
trial
residue
data
(
Attachment
2).
Maximum
likelihood
estimation
(
MLE)
techniques
were
used
to
supplement
the
dried
bean
dataset.
Based
on
visual
inspection
of
the
probability
plot,
the
lognormality
assumption
was
rejected
[
HED
Science
Advisory
Council
for
Chemistry
(
ChemSAC)
meeting
of
3/
8/
06].
The
value
derived
by
the
California
Method
(
0.15
ppm)
was
thus
deemed
to
be
appropriate.
Revised
Sections
F
with
the
correct
tolerance
levels
and
commodity
definitions
should
be
submitted
where
appropriate.

The
available
potato
data
will
support
a
tolerance
of
0.05
ppm
on
tuberous
and
corm
vegetables
(
subgroup
1C),
and
the
mustard
green
data
will
support
a
tolerance
of
3.5
ppm
on
leafy
Brassica
vegetables
(
subgroup
5B).
The
data
on
dried
beans
and
peas
will
support
a
tolerance
of
0.15
ppm
on
shelled
dried
beans
and
peas,
excluding
soybean
(
subgroup
6C).
The
data
on
cilantro
(
coriander)
will
support
separate
tolerances
of
5
ppm
in/
on
coriander
leaves
and
seed.
Based
on
the
HAFT
residues
observed
for
coriander
leaves
(
3.96
ppm)
and
the
observed
processing
factor
of
5.7x
for
dried
leaves,
the
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
35
of
50
maximum
expected
residues
in/
on
dried
leaves
would
be
22.6
ppm,
which
will
support
at
tolerance
of
25
ppm
for
dried
coriander
leaves.

Table
4.1.5.1.
Tolerance
Summary
for
Bifenthrin
Crop
Commodity
Proposed
Tolerance
(
ppm)
Recommended
Tolerance
(
ppm)
Comments
(
correct
commodity
definition)

Tuberous
and
corm
vegetables,
subgroup
1C
0.1
0.05
Vegetable,
tuberous
and
corm,
subgroup
1C
Brassica,
leafy
greens,
subgroup
5B1
3
3.5
Turnip
greens1
3
3.5
Turnip,
greens
Pea
and
bean,
dried
shelled,
except
soybean,
subgroup
0.1
0.15
Pea
and
bean,
dried
shelled,
except
soybean,
subgroup
6C
Cilantro,
leaves
5.0
6.0
Coriander,
leaves
Cilantro,
dried
leaves
30.0
25
Coriander,
dried
leaves
Coriander,
seed
5.0
5.0
1
Turnip
greens
will
be
removed
from
Crop
Group
2:
Leaves
of
root
and
tuber
vegetables
group
[
40
CFR
180.41
(
2)],
and
will
become
a
member
of
Crop
Group
5:
Brassica
leafy
vegetables
[
40
CFR
180.41
(
5)].
It
will
also
be
a
member
of
Crop
Subgroup
5B:
Leafy
Brassica
greens
(
Commodity
Reviewers
Guide,
B.
Schneider,
14­
JUN­
2002).
Until
that
time,
"
turnip,
greens"
should
have
a
separate
tolerance.

4.1.6
International
Residue
Limits
The
Codex
Alimentarius
Commission
has
established
maximum
residue
limits
(
MRLs)
for
residues
of
bifenthrin
in/
on
various
commodities.
Codex
MRLs
are
expressed
in
terms
of
bifenthrin
per
se,
as
are
U.
S.
tolerances.
The
only
established
Codex
MRL
relevant
to
the
current
petitions
is
for
potato
at
0.05
mg/
kg
(
See
attached
International
Residue
Limits
Status
sheet).
As
the
recommended
tolerance
of
tuberous
and
corm
vegetables
is
also
0.05
ppm,
this
tolerance
is
in
harmony
with
the
Codex
MRL
for
potato.
There
are
no
equivalent
Canadian
or
Mexican
MRLs
for
the
tolerances
being
requested
in
the
current
petition.

4.1.7
Drinking
Water
Residue
Profile
Tier
I
Estimated
Environmental
Concentrations
of
Bifenthrin
for
the
Use
in
the
Human
Health
Risk
Assessment.
02/
07/
2006.
J.
Melendez
Residues
of
Concern
in
Drinking
Water
The
HED
MARC
concluded
that
the
parent
compound,
bifenthrin
per
se,
should
be
the
residue
of
concern
for
drinking
water
risk
assessment
based
on
its
persistence
and
the
absence
of
major
degradates
in
laboratory
studies
(
HED
Doc.
No.
0050887).

Drinking
Water
Estimates
The
EDWCs
for
bifenthrin
were
calculated
based
on
a
maximum
application
rate
of
0.5
lb
ai/
A/
season.
The
acute
drinking
water
concentration
in
surface
water
is
0.0140
ppb
of
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
36
of
50
bifenthrin,
based
on
aerial
applications
to
lettuce.
The
cancer/
chronic
drinking
water
concentration
is
0.0140
ppb
(
based
on
applications
of
lettuce,
highest
application
rate).
The
SCI­
GROW
generated
EDWC
is
0.00300
ppb
of
bifenthrin,
which
is
recommended
for
use,
both
for
acute
and
chronic
exposures.
Because
of
the
very
low
solubility
of
bifenthrin,
the
EDWCs
did
not
exceed
0.0140
ppb
(
the
solubility
of
bifenthrin).

Table
4.1.7.
Tier
1
Estimated
Drinking
Water
Concentrations
for
Bifenthrin
DRINKING
WATER
SOURCE
(
MODEL
USED)
USE
(
rate
modeled)
MAXIMUM
ESTIMATED
DRINKING
WATER
CONCENTRATION
(
EDWC)
(
ppb)

Groundwater
(
SCI­
GROW)
Lettuce
(
0.5
lb.
ai/
A/
season)
Acute
and
Chronic
0.00300
Lettuce
(
0.5
lb.
ai/
A/
season)
Acute
0.0140
Surface
water
(
FIRST)

Lettuce
(
0.5
lb.
ai/
A/
season)
Chronic
0.0140
4.2
Dietary
Exposure
and
Risk
Acute
and
chronic
dietary
exposure
and
risk
assessments
were
conducted
using
the
Model
(
DEEM­
FCID
 
,
Version
2.03)
which
uses
food
consumption
data
from
the
U.
S.
Department
of
Agriculture's
CSFII
from
1994­
1996
and
1998.
The
analyses
were
performed
as
part
of
a
registration
action;
(
1)
to
support
Interregional
Research
Project
No.
4
(
IR­
4)
tolerance
petitions
for
pending
uses
on
dried
peas
and
beans,
cilantro,
Brassica
leafy
vegetables,
and
tuberous
and
corm
vegetables;
(
2)
to
include
drinking
water
estimates;
and
(
3)
to
support
the
new
acute
toxicological
endpoint.

4.2.1
Acute
Dietary
Exposure
and
Risk
The
acute
dietary
exposure
estimates
for
food
and
drinking
water
are
below
HED's
level
of
concern
(<
100%
aPAD)
at
the
99.9th
percentile
of
exposure
(
see
Table
4.2.1).
Bifenthrin
dietary
exposure
at
the
99.9th
percentile
for
food
and
drinking
water
for
the
U.
S.
population
is
21%
of
the
aPAD
and
41%
of
the
aPAD
for
children
1­
2
yrs,
the
most
highly
exposed
population
subgroup.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
37
of
50
Table
4.2.1.
Results
of
Bifenthrin
Acute
Dietary
(
Food
+
Drinking
Water)
Exposure
Analysis
Using
DEEM
FCID
99.9th
Percentile
Population
Subgroup
aPAD
(
mg/
kg/
day)
Exposure
(
mg/
kg/
day)
%
aPAD
General
U.
S.
Population
0.033
0.006953
21
All
Infants
(<
1
year
old)
0.033
0.012335
37
Children
1­
2
years
old
0.033
0.013472
41
Children
3­
5
years
old
0.033
0.011708
35
Children
6­
12
years
old
0.033
0.004966
15
Youth
13­
19
years
old
0.033
0.006087
18
Adults
20­
49
years
old
0.033
0.004808
15
Adults
50+
years
old
0.033
0.005373
16
Females
13­
49
years
old
0.033
0.004567
14
4.2.1
Chronic
Dietary
Exposure
and
Risk
The
chronic
dietary
exposure
estimates
for
food
and
drinking
water
are
below
HED's
level
of
concern
(<
100%
cPAD)
for
the
U.
S.
population
and
all
population
subgroups
(
Table
4.2.2).
Bifenthrin
dietary
exposure
for
food
and
drinking
water
for
the
U.
S.
population
is
6%
of
the
cPAD
and
18%
of
the
cPAD
for
children
1­
2
yrs,
the
most
highly
exposed
population
subgroup.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
38
of
50
Table
4.2.2:
Summary
of
Dietary
Exposure
and
Risk
for
Bifenthrin
Acute
Dietary
(
99.9th
Percentile)
Chronic
Dietary
Population
Subgroup
Dietary
Exposure
(
mg/
kg/
day)
%
aPAD
Dietary
Exposure
(
mg/
kg/
day)
%
cPAD
General
U.
S.
Population
0.006957
21
0.000228
6
All
Infants
(<
1
year
old)
0.012335
37
0.000369
9
Children
1­
2
years
old
0.013472
41
0.000715
18
Children
3­
5
years
old
0.011708
35
0.000489
12
Children
6­
12
years
old
0.004966
15
0.000272
7
Youth
13­
19
years
old
0.006087
18
0.000166
4
Adults
20­
49
years
old
0.004805
15
0.000196
5
Adults
50+
years
old
0.005373
16
0.000173
4
Females
13­
49
years
old
0.004564
14
0.000144
4
5.0
Residential
(
Non­
Occupational)
Exposure/
Risk
Characterization
Bifenthrin:
REVISED
Residential
Exposure
Assessment
and
Recommendations
for
the
Tolerance
Reassessment
Eligibility
Decision
(
TRED)
Document.
S.
Weiss.
D286358.
10/
25/
2002.

Bifenthrin
products
are
available
to
homeowners
for
indoor
and
outdoor
application
to
residential
premises.
Adults
and
children
may
be
potentially
exposed
to
bifenthrin
residues
resulting
from
application.

Potential
exposure
and
risk
to
residents
(
or
"
homeowners")
have
been
assessed
previously
by
HED.
Information
for
this
section
was
adapted
from
previous
residential
assessment
for
bifenthrin
performed
in
2002
(
see
reference
below).
Since
completion
of
the
last
residential
assessment,
no
product
cancellations
have
occurred
that
would
alter
the
conclusions.
A
summary
of
the
exposure
and
risk
resulting
from
residential
uses
of
bifenthrin
is
provided
below.
These
exposure
estimates
were
used
in
the
aggregate
risk
assessment
which
appears
in
Section
7.0
of
this
document.

5.1
Residential
Handler
Exposure
End
use
products
containing
bifenthrin
are
formulated
as
ready­
to­
use­
sprays,
emulsified
concentrates,
wettable
powders,
granulars,
pelletized
tablets,
and
pressurized
liquids.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
39
of
50
The
current
maximum
application
rates
of
granulars
and
liquids
by
lawn
care
operators
(
LCOs)
are
0.4
and
0.3
lb
ai/
acre,
respectively.
For
liquid
and
granular
formulations
applied
by
homeowners,
the
maximum
rate
is
0.2
lb
ai/
acre.
In
a
letter
to
the
Agency
dated
September
16,
2002,
FMC
agreed
to
lower
the
maximum
rate
for
all
turf
uses
to
0.2
lb
ai/
acre.
Bifenthrin
products
may
be
applied
by
pest
control
operators
(
PCOs)
and
homeowners
in
and
around
homes
as
a
spray
in
concentrations
of
up
to
0.06%.
The
majority
of
residential
labels
do
not
specify
frequency
of
application.

On
October
25,
2002,
HED
performed
a
residential
exposure
and
risk
assessment
for
the
use
of
bifenthrin
(
see
reference
above).
A
summary
of
the
uses
and
the
results
of
the
assessment
are
summarized
below.
For
more
details
and
for
the
results
of
all
exposure
scenarios,
please
see
the
original
residential
exposure
assessment.

Short­
and
intermediate­
term
exposures
may
occur
for
residents
applying
bifenthrin
products.
Chronic
exposures
are
not
anticipated
for
residential
handlers.
The
exposure
and
risk
for
residential
handlers
were
assessed
using
the
revised
draft
SOPs
for
Residential
Exposure
Assessment,
and
includes
surrogate
data
from
the
Pesticide
Handlers
Exposure
Database
(
PHED),
Outdoor
Residential
Exposure
Task
Force
(
ORETF).
Since
PHED
and
ORETF
do
not
include
data
for
ready­
to­
use
spray
bottle
application,
data
from
a
proprietary
study
were
used
to
estimate
exposure
(
MRID
447393­
01).

The
major
exposure
scenarios
for
non­
occupational
(
residential)
handler
exposures
are
as
follows:
*
Mixing/
loading/
applying
Liquids
for
Low
Pressure
Handwand
Application
*
Mixing/
loading/
applying
Liquids
for
Hose­
end
Sprayer
Application
*
Mixing/
loading/
applying
Liquids
for
Backpack
Sprayer
Application
*
Paintbrush
Application
*
Loading/
applying
Granulars
for
Belly
Grinder
Application
*
Loading/
applying
Granulars
for
Push­
type
Spreader
Application
*
Applying
Granulars
with
Bare
Hands
*
RTU
Spray
Bottle
Application
The
most
likely
residential
handler
exposure
scenario
resulting
in
the
highest
exposure
and
risk
is
for
mixing/
loading
and
applying
liquids
using
a
hose­
end
broadcast
sprayer.
The
short­
and
intermediate­
term
MOE
for
this
use
is
2900
(
dermal
and
inhalation
MOEs
were
summed).

This
use
does
not
exceed
HED's
level
of
concern.
Short­
and
intermediate­
term
risks
estimated
for
residential
handlers
and
for
post­
application
exposure
do
not
exceed
HED's
level
concern.
Long­
term
exposure
is
not
expected.

5.2
Residential
Post­
application
Exposure
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
40
of
50
Adults
and
children
may
be
potentially
exposed
to
bifenthrin
residues
after
application
of
bifenthrin
products
in
residential
settings.
Short­
and
intermediate­
term
post­
application
dermal
exposures
for
adults,
and
short­
and
intermediate­
term
post­
application
dermal
and
incidental
oral
exposures
for
children
are
anticipated.
Long­
term
exposure
is
not
expected.
Risk
estimates
were
generated
for
potential
contact
with
lawn,
soil,
and
treated
indoor
surfaces
using
HED's
Draft
SOPs
for
Residential
Exposure
Assessment,
and
for
the
lawn
scenarios,
dissipation
data
from
a
chemical
specific
TTR
study.
Indoor
surface
residues
in
homes
were
based
on
crack
and
crevice
data
collected
for
bifenthrin
and
malathion.
These
estimates
are
considered
conservative
screening
level
estimates,
but
appropriate,
since
the
study
data
were
adjusted
to
reflect
maximum
application
rates.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
41
of
50
Table
5.2
Summary
of
Residential
Post­
Application
Exposure
Scenarios
for
Bifenthrin
Exposure
Scenario
Population
Route
of
Exposure
Short­
Term
MOE
Intermediate­
Term
MOE
Adults
Dermal
3100
3100
Indoor:
High
Contact
Activity
Toddlers
Dermal
1800
1800
Adults
Dermal
2300
4500
Outdoor:
High
Contact
Activity
on
Turfgrass
Toddler
Oral
and
Dermal
740
Oral
1400
Dermal
1600
Oral
2700
Dermal
5.3
Other
(
Spray
Drift)

Spray
drift
is
always
a
potential
source
of
exposure
to
residents
nearby
to
spraying
operations.
This
is
particularly
the
case
with
aerial
application,
but,
to
a
lesser
extent,
could
also
be
a
potential
source
of
exposure
from
the
ground
application
method
employed
for
bifenthrin.
The
Agency
has
been
working
with
the
Spray
Drift
Task
Force,
EPA
Regional
Offices
and
State
Lead
Agencies
for
pesticide
regulation
and
other
parties
to
develop
the
best
spray
drift
management
practices.
On
a
chemical
by
chemical
basis,
the
Agency
is
now
requiring
interim
mitigation
measures
for
aerial
applications
that
must
be
placed
on
product
labels/
labeling.
The
Agency
has
completed
its
evaluation
of
the
new
database
submitted
by
the
Spray
Drift
Task
Force,
a
membership
of
U.
S.
pesticide
registrants,
and
is
developing
a
policy
on
how
to
appropriately
apply
the
data
and
the
AgDRIFT7
computer
model
to
its
risk
assessments
for
pesticides
applied
by
air,
orchard
airblast
and
ground
hydraulic
methods.
After
the
policy
is
in
place,
the
Agency
may
impose
further
refinements
in
spray
drift
management
practices
to
reduce
off­
target
drift
with
specific
products
with
significant
risks
associated
with
drift.

6.0
Aggregate
Risk
Assessments
and
Risk
Characterization
In
accordance
with
the
FQPA,
HED
must
consider
and
aggregate
pesticide
exposures
and
risks
from
three
major
sources:
food,
drinking
water,
and
residential
exposures.
In
an
aggregate
assessment,
exposures
from
dietary
and
residential
sources
are
added
together
and
compared
to
quantitative
estimates
of
hazard
(
e.
g.,
a
NOAEL),
or
the
risks
themselves
can
be
aggregated.
When
aggregating
exposures
and
risks
from
various
sources,
HED
considers
both
the
route
and
duration
of
exposure.

Short­
term
aggregate
risk
assessment
is
required
for
bifenthrin
due
to
the
potential
for
residential
exposure.
The
common
toxicological
effect
observed
across
the
oral
and
dermal
routes
of
exposure
is
clinical
signs
of
neurotoxicity.
An
aggregate
MOE
was
calculated
by
taking
the
inverse
of
the
sum
of
inverse
MOEs
for
dietary
and
non­
dietary
(
incidental
oral
and
dermal)
exposure
pathways.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
42
of
50
6.1
Acute
Aggregate
Risk
No
acute
residential/
recreational
exposures
are
expected
and
since
the
dietary
assessment
included
food
and
water,
the
exposures
in
Table
5.2.1
represent
aggregate
exposures.
The
values
are
below
HED's
level
of
concern.

6.2
Short­
and
Intermediate­
term
Aggregate
Risk
Because
there
is
the
potential
for
short­
and
intermediate­
term,
non­
dietary
exposure
of
children
and
adults
to
bifenthrin
as
a
residential
treatment
(
indoors
and
outdoors),
it
is
appropriate
to
aggregate
these
exposures
with
dietary
(
food
and
water)
exposure.
Adults
can
be
exposed
through
the
residential
application
of
bifenthrin
via
dermal
and
inhalation
routes
and
through
postapplication
exposure
via
the
dermal
route
(
treated
turf).
Children
might
be
exposed
following
application
in
residential
settings
via
dermal
and
oral
routes.
HED
believes
that
if
a
toddler
were
to
be
exposed
to
bifenthrin
granules,
it
would
most
likely
be
episodic,
that
is,
a
one­
time
occurrence
and
not
likely
to
be
repeated.
Therefore,
this
episodic
scenario
was
not
aggregated
with
dietary
exposure.

Residential
exposure
and
risk
have
been
summarized
based
on
HED
residential
risk
assessments
for
the
existing
uses
of
bifenthrin.
Those
scenarios
resulting
in
the
highest
exposure
and
risk
for
adults
and
children
have
been
summarized
in
Table
6.2.
These
exposures
were
used
to
calculated
short­
andintermediate­
term
aggregate
risk
by
combining
residential
exposure
with
that
from
dietary
sources.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
43
of
50
Table
6.2
Summary
of
Residential
Risk
Scenarios
Resulting
in
Highest
Exposure
and
Risk
for
Bifenthrin
Population
Exposure
Scenario
Route
of
Exposure
Short­
Term
MOE
Handler
Dermal
and
Inhalation
97,000
Inhalation
3000
Dermal
Hose­
end
Sprayer
Application
Post­
Application
Dermal
2300
Handler
Dermal
and
Inhalation
23,000
Inhalation
600
Dermal
Liquid
Structural
Wood
Treatment
with
Paintbrush
Post­
Application
No
exposure
expected
due
to
low
accessibility
to
treated
areas
(
termite
control).

Handler
Dermal
and
Inhalation
210,000
Inhalation
14,000
Dermal
Adults
Indoor:
Liquid
Crack
and
Crevice
Spray
Post­
Application
Dermal
3100
Hand­
to­
Mouth/
Oral
740
Mouthing
Treated
Turf
3000
Soil
Ingestion
220,000
Toddler
Outdoor:
High
Contact
Activity
on
Turfgrass
Post­
Application
Dermal
1400
1.
Combined
MOE
for
handlers
since
dermal
and
inhalation
endpoints
(
clinical
signs
of
same
[
1/(
1/
MOEdermal
1/
MOE­
inhalation)].

The
short­
and
intermediate­
term
NOAEL
for
non­
dietary
oral
exposure
is
based
on
the
90­
day
oral
toxicity
study
in
dogs
(
NOAEL
=
2.21
mg/
kg/
day).
The
short­
and
intermediate­
term
NOAEL
dermal
exposure
is
based
on
the
21­
day
dermal
toxicity
study
in
the
rat
(
NOAEL
=
47
mg/
kg/
day).
The
common
toxicological
effect
observed
across
the
oral
and
dermal
routes
of
exposure
is
clinical
signs
of
neurotoxicity.
The
aggregate
LOC
(
MOE)
is
300.

The
results
of
the
short­
and
intermediate­
term
aggregate
risk
assessment
for
various
subpopulations
based
on
age
are
reported
in
Table
6.2.1.
Short­
and
intermediate­
term
aggregate
(
dietary
+
residential)
MOEs
for
the
general
US
population
and
any
subpopulation
of
the
general
US
population
are
>
300
and
do
not
exceed
HED's
level
of
concern.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
44
of
50
Table
6.2.1.
Short­
and
Intermediate­
Term
Aggregate
Risk
for
Bifenthrin
Population
Dietary
MOE1
Non­
dietary
Oral
MOE2
Dermal
MOE3
Inhalation
MOE4
Aggregate
MOE5
General
US
population
9700
N/
A
600
23,000
550
All
infants
(<
1
yr
old)
6000
590
1400
390
Children
1­
2
yrs.
Old
3100
590
1400
370
Children
3­
5
yrs.
Old
4500
590
1400
380
Children
6­
12
yrs.
Old
8100
1400
1200
Youth
13­
19
yrs.
Old
13,000
1400
N/
A
1300
Adults
20­
49
yrs.
Old
11,000
600
23,000
550
Adults
50+
yrs.
Old
13,000
600
23,000
560
Females
13­
49
yrs.
Old
15,000
N/
A
510
23,000
480
1
Dietary
MOE
=
[(
short­
or
intermediate­
term
oral
NOAEL)
÷
(
chronic
dietary
exposure)];
NOAEL=
2.21
mg/
kg/
day;
chronic
dietary
(
food
+
water)
exposures
(
see
Table
5.2.2)
were
utilized
as
surrogates
for
short­
and
intermediate­
term
exposures
2
Non­
dietary
oral
MOE
=
[(
short­
or
intermediate­
term
oral
NOAEL)
÷
(
sum
of
all
high­
end
incidental
oral
residential
exposure)];
NOAEL=
2.21
mg/
kg/
day;
chronic
dietary
(
food
+
water)
exposures
(
see
Table
4.2.2)
were
utilized
as
surrogates
for
short­
and
intermediate­
term
exposures.
3
Dermal
MOE
=
[(
short­
or
intermediate­
term
dermal
NOAEL)
÷
(
high­
end
dermal
residential
exposure)];
NOAEL=
47
mg/
kg/
day;
structural
wood
treatment
(
paintbrush
application)
used
for
adult
estimates
4
Inhalation
MOE
=
[(
short­
or
intermediate­
term
inhalation
NOAEL)
÷
(
high­
end
dermal
residential
exposure)];
NOAEL=
2.21
mg/
kg/
day
5
Aggregate
MOE
(
dietary
and
residential)
=
1
÷
[
(
1
÷
Dietary
MOE)
+
(
1
÷
Non­
dietary
oral
MOE)
+
(
1
÷
Dermal
MOE)
+
(
1
÷
Inhalation
MOE)];
values
expressed
to
2
significant
figures;
Inhalation
MOE
based
on
adult
residential
handler
exposure
(
intermediate­
term
not
likely).
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
45
of
50
6.3
Long­
term
(
Chronic)
Aggregate
Risk
A
chronic
(
non­
cancer)
aggregate
risk
assessment
was
not
performed,
because
chronic
residential
exposure
to
bifenthrin
(
i.
e.,
>
6
months)
is
not
considered
likely
to
occur.

6.4
Cancer
Risk
The
CARC
(
1992)
recommended
that
for
the
purpose
of
risk
characterization,
the
reference
dose
(
RfD)
approach
should
be
used
for
quantification
of
human
risk.
The
chronic
exposure
analysis
revealed
<
100%
RfD,
and
it
is
assumed
that
the
chronic
dietary
endpoint
is
protective
for
cancer
dietary
exposure.

7.0
Cumulative
Risk
Characterization/
Assessment
Bifenthrin
is
a
member
of
the
pyrethroid
class
of
pesticides.
EPA
is
not
currently
following
a
cumulative
risk
approach
based
on
a
common
mechanism
of
toxicity
for
the
pyrethroids.
Although
all
pyrethroids
alter
nerve
function
by
modifying
the
normal
biochemistry
and
physiology
of
nerve
membrane
sodium
channels,
available
data
show
that
there
are
multiple
types
of
sodium
channels
and
it
is
currently
unknown
whether
the
pyrethroids
as
a
class
have
similar
effects
on
all
channels
or
whether
modifications
of
different
types
of
sodium
channels
would
have
a
cumulative
effect.
Nor
do
we
have
a
clear
understanding
of
effects
on
key
downstream
neuronal
function,
e.
g.,
nerve
excitability,
or
how
these
key
events
interact
to
produce
their
compound
specific
patterns
of
neurotoxicity.
Without
such
understanding,
there
is
no
basis
to
make
a
common
mechanism
of
toxicity
finding.
There
is
ongoing
research
by
the
EPA's
Office
of
Research
and
Development
and
pyrethroid
registrants
to
evaluate
the
differential
biochemical
and
physiological
actions
of
pyrethroids
in
mammals.
This
research
is
expected
to
be
completed
by
2007.
When
available,
the
Agency
will
consider
this
research
and
make
a
determination
of
common
mechanism
as
a
basis
for
assessing
cumulative
risk.
For
information
regarding
EPA's
procedures
for
cumulating
effects
from
substances
found
to
have
a
common
mechanism
on
EPA's
website
at
http://
www.
epa.
gov/
pesticides/
cumulative/.

8.0
Occupational
Exposure/
Risk
Pathway
8.1
Short­/
Intermediate­
Term
Handler
Risk
Based
upon
the
proposed
use
pattern,
HED
expects
the
most
highly
exposed
occupational
pesticide
handlers
(
mixers,
loaders,
applicators)
to
be
1)
mixer/
loader
using
open
pour
loading
of
liquids;
2)
mixer/
loader
using
open
pour
loading
of
granules;
3)
an
aerial
applicator
and
4)
an
applicator
using
open­
cab,
ground­
boom
spray
equipment.
HED
believes
most
exposure
durations
will
be
short­
term
(
1
­
30
days).
However,
the
Science
Policy
Council
for
Exposure
(
ExpoSAC)
maintains
that
it
is
possible
for
commercial
applicators
to
be
exposed
to
intermediate
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
46
of
50
term
exposure
durations
(
1
­
6
months).
Therefore
estimates
for
short­
and
intermediate­
term
risks
are
presented.

It
is
expected
that
some
private
applicators
may
perform
all
tasks,
that
is,
mix,
load
and
apply
the
material.
However,
HED
ExpoSAC
draft
SOP
(
29
March
2000)
directs
that
although
the
same
individual
may
perform
all
tasks,
in
some
cases
they
shall
be
assessed
separately.

The
available
exposure
data
for
combined
mixer/
loader/
applicator
scenarios
are
limited
in
comparison
to
the
monitoring
of
these
two
activities
separately.
These
exposure
scenarios
are
outlined
in
the
PHED
Surrogate
Exposure
Guide
(
August
1998).
HED
has
adopted
a
methodology
to
present
the
exposure
and
risk
estimates
separately
for
the
job
functions
in
some
scenarios
and
to
present
them
as
combined
in
other
cases.
Most
exposure
scenarios
for
hand­
held
equipment
(
such
as
hand
wands,
backpack
sprayers,
and
push­
type
granular
spreaders)
are
assessed
as
a
combined
job
function.
With
these
types
of
hand
held
operations,
all
handling
activities
are
assumed
to
be
conducted
by
the
same
individual.
The
available
monitoring
data
support
this
and
HED
presents
them
in
this
way.
Conversely,
for
equipment
types
such
as
fixedwing
aircraft,
groundboom
tractors,
air­
blast
sprayers,
or
high­
pressure
handwand
sprayers,
the
applicator
exposures
are
assessed
and
presented
separately
from
those
of
the
mixers
and
loaders.
By
separating
the
two
job
functions,
HED
determines
the
most
appropriate
levels
of
PPE
for
each
aspect
of
the
job
without
requiring
an
applicator
to
wear
unnecessary
PPE
that
might
be
required
for
a
mixer/
loader
(
e.
g.,
chemical
resistant
gloves
may
only
be
necessary
during
the
pouring
of
a
liquid
formulation).

No
chemical
specific
data
were
available
with
which
to
assess
potential
exposure
to
occupational
pesticide
handlers.
The
estimates
of
exposure
to
pesticide
handlers
are
based
upon
surrogate
study
data
available
in
the
PHED
(
v.
1.1,
1998).
For
pesticide
handlers,
it
is
HED
standard
practice
to
present
estimates
of
dermal
exposure
for
"
baseline"
that
is,
for
workers
wearing
a
single
layer
of
work
clothing
consisting
of
a
long
sleeved
shirt,
long
pants,
shoes
plus
socks
and
no
protective
gloves
as
well
as
for
"
baseline"
and
the
use
of
protective
gloves
or
other
PPE
as
might
be
necessary.
The
proposed
product
label
involved
in
this
assessment
directs
applicators
and
other
handlers
who
may
be
exposed
to
the
dilute
through
application
or
other
tasks
must
wear:
long­
sleeved
shirt
and
long
pants,
chemical
resistant
gloves,
such
as
barrier
laminate,
nitrile,
neoprene
or
viton
rubber
and
shoes
plus
socks.
Handlers
who
may
be
exposed
to
the
concentrate
through
mixing,
loading,
application
or
other
tasks
must
wear;
long­
sleeved
shirt
and
long
pants,
chemical
resistant
gloves
such
as
barrier
laminate,
nitrile,
neoprene
or
viton
rubber,
shoes
plus
socks
and
protective
eye
wear.

Since
single
application
rates
for
the
proposed
uses
range
from
0.1
lb
ai/
acre
to
0.3
lb
ai/
acre,
those
uses
with
the
higher
application
rate
were
assessed
in
the
table
below
(
potatoes).
Since
the
dermal
effects
are
derived
from
a
21­
day
dermal
study,
there
are
no
adjustments
made
for
dermal
absorption.
HED
asssumes
100%
inhalation
absorption.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
47
of
50
See
Table
9.1
for
a
summary
of
estimated
exposures
and
risks.
In
this
case,
the
toxicological
effects
are
similar
(
i.
e.,
neurological)
for
the
dermal
and
inhalation
routes
although
they
were
identified
from
different
studies.
Therefore,
MOEs
are
expressed
as
Combined
MOEs.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
48
of
50
Table
8.1
Occupational
Exposure
and
Risk
Estimates
for
Proposed
Uses
of
Bifenthrin
Unit
Exposure1
(
mg
ai/
lb
ai
handled)
Acres
Treated2
Average
Daily
Dose3
(
mg
ai/
kg
bw/
day)
MOE4
Combined
MOE5
Mixer/
Loader
 
Liquids
 
Open
Pour
 
Supporting
Aerial
Applications
Dermal:
SLNG:
2.9
HC
SLWG:
0.023
HC
Dermal:
NG:
4.35
WG:
0.0345
NG:
11
WG:
1400
Inhal:
0.0012
350
Acres/
Day
Inhal:
0.0018
Inhal:
1200
NG:
11
WG:
650
Mixer/
Loader
 
Granules
 
Open
Pour
Dermal:
SLNG:
0.0084
LC
SLWG:
0.0069
MC
Dermal:
NG:
0.0126
WG:
0.0104
NG:
3700
WG:
4500
Inhal:
0.0017
350
Acres/
Day
Inhal:
0.00255
Inhal:
870
NG:
700
WG:
730
Aerial
Applicator6
Dermal:
SLNG:
0.0050
Dermal:
NG:
0.0075
NG:
6300
Inhal:
0.000068
350
Acres/
Day
Inhal:
0.00010
Inhal:
22,000
NG:
4900
Applicator
 
Open
Cab
 
Ground
Boom
Dermal:
SLNG:
0.014
SLWG:
0.014
Dermal:
SLNG:
0.012
SLWG:
0.012
NG:
3900
WG:
3900
Inhal:
0.00074
200
Acres/
Day
Inhal:
0.00063
Inhal:
3500
NG:
1800
WG:
1800
1.
Unit
exposure
=
mg/
lb
ai
handled;
taken
from
PHED
Surrogate
Exposure
Guide
(
v.
1.1,
8/
1998)
SLNG=
single
layer
PPE,
no
gloves;
SLWG=
single
layer
PPE
with
gloves.
HC=
high
confidence
data;
MC=
medium
confidence
data;
LC=
low
confidence
data.
2.
Acres
treated
are
derived
from
ExpoSAC
Policy
No.
9.1,
revised
9/
25/
2001.
3.
Average
Daily
Dose
(
ADD)
=
Unit
Exposure*
Application
Rate*
Acres
Treated
÷
70
kg
body
weight.
4.
MOE=
Margin
of
Exposure
(
MOE)
=
NOAEL
÷
ADD.
5.
Margins
of
Exposure
may
be
combined
when
the
dermal
and
inhalation
toxicological
effect
is
the
same
but
derived
from
different
studies.
The
convention
used
to
combine
is:
1
÷
[(
1/
MOE­
DERMAL
)
+
(
1/
MOE­
INHALATION)]
6.
Pilots
are
not
required
to
wear
protective
gloves.

A
MOE
of
100
is
adequate
to
protect
occupational
pesticide
handlers.
Provided
that
mixer/
loaders
wear
protective
gloves,
all
MOEs
are
>
100.
Therefore
the
estimated
risks
do
not
exceed
HED's
levels
of
concern.

8.1
Short­/
Intermediate­
Term
Post­
application
Risk
There
is
typically
the
possibility
for
agricultural
workers
to
experience
post­
application
exposure
to
dislodgeable
pesticide
residues.
In
conjunction
with
the
Agricultural
Re­
Entry
Task
Force
(
ARTF),
HED
has
identified
a
number
of
agricultural
work
activities
that
may
result
in
postapplication
re­
entry
exposure
to
pesticides.
In
addition,
HED
has
identified
surrogate
Transfer
Coefficients
(
TCs)
in
units
of
cm
²
/
hr
derived
from
exposure
studies
relative
to
"
standard"
agricultural
work
activities
but
which
were
conducted
to
assess
exposure
to
other
compounds.

Not
all
of
the
identified
post­
application
work
activities
are
listed
here.
However,
the
activities
associated
with
the
highest
TCs
are
summarized
in
Table
9.2.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
49
of
50
Table
8.2
Transfer
Coefficients
Associated
With
Proposed
Uses
of
Bifenthrin
Crop
Activity
Transfer
Coefficient
(
cm2/
hr)
Leafy
green
vegetables
(
cilantro)
2500
Brassica
leafy
greens
2500
Beans,
Peas
­
dried,
shelled
Hand
Harvesting
2500
Tobacco
Hand
Harvesting,
Topping,
Stripping
2000
Roots
and
tuber
(
potatoes)
Irrigation
activities,
Scouting
1500
Since
there
are
no
chemical
specific
data
with
which
to
assess
post­
application
exposures
to
agricultural
workers,
HED
uses
TCs
identified
from
surrogate
studies
in
conjunction
with
the
assumption
that
20%
of
the
rate
of
application
is
available
as
dislodgeable
foliar
residue
(
DFR)
on
day
zero
after
application.
Although
hand
harvesting
(
cilantro,
leafy
greens
and
peas
and
beans)
has
a
TC
of
2,500,
the
rate
of
application
is
0.1
lb
ai/
A.
The
rate
of
application
for
potato
is
0.3
lb
ai/
A
which
results
in
a
higher
exposure
despite
a
slightly
lower
TC.
Therefore,
as
a
"
worse
case",
screening
level
assessment,
a
TC
of
1500
cm
²
/
hr
is
used
in
conjunction
with
an
application
rate
of
0.3
lb
ai/
A.

The
TCs
used
in
this
assessment
are
from
an
interim
TC
policy
developed
by
HED's
ExpoSAC
using
proprietary
data
from
the
ARTF
database
(
policy
#
3.1
Revised
7
AUG
2000).
It
is
the
intention
of
HED's
ExpoSAC
that
this
policy
will
be
periodically
updated
to
incorporate
additional
information
about
agricultural
practices
in
crops
and
new
data
on
TC's.
Much
of
this
information
will
originate
from
exposure
studies
currently
being
conducted
by
the
ARTF,
from
further
analysis
of
studies
already
submitted
to
the
Agency,
and
from
studies
in
the
published
scientific
literature.
The
following
convention
may
be
used
to
estimate
post­
application
exposure
to
agricultural
workers.

Surrogate
Dislodgeable
Foliar
Residue:
DFR
=
application
rate
*
20%
available
as
dislodgeable
residue
*
4.54
x
108
µ
g/
lb
*
2.47
x
10­
8
A/
cm2
or
1.08
x
10­
3
ft2/
cm
²

and
the
Average
Daily
Dose
ADD
=
DFR
(
µ
g/
cm2)
*
TC
(
cm2/
hr)
*
hr/
day
*
0.001
mg/
µ
g
*
1/
70
kg
bw

0.3
b
ai/
A
*
0.20
*
4.548
µ
g/
lb
*
2.47­
8
A/
cm
²
=
0.673
g/
cm2
and
0.673
µ
g/
cm2
*
1500
cm2/
hr
*
8
hr/
day
*
0.001
mg/
µ
g
*
1/
70
kg
bw
=
0.12
mg/
kg
bw/
day
Since
MOE
=
NOAEL
÷
ADD
then
47
mg/
kg
bw/
day
÷
0.12
mg/
kg
bw/
day
=
410
The
MOE
for
the
theoretically
most
highly
exposed
post­
application
agricultural
activity
is
410
(
greater
than100),
and
does
not
exceed
HED's
level
of
concern.
All
other
identified
postapplication
activities
are
expected
to
have
lower
exposures
therefore
greater
MOEs.
Bifenthrin
Human
Health
Risk
Assessment
PC
Code:
128825
Page
50
of
50
HED
notes
that
in
the
occupational
exposure
assessment
which
is
the
basis
of
this
section,
a
discrepancy
was
discovered
relative
to
the
application
rate
for
tobacco
(
stated
as
0.3
lb
ai/
acre).
The
correct
application
rate
for
tobacco
is
0.1
lb
ai/
acre.

RESTRICTED
ENTRY
INTERVAL
(
REI)

HED
is
not
aware
of
possible
REIs
proposed
for
cilantro,
tobacco
and
tuberous
and
corm
vegetables.
The
restricted
entry
intervals
for
bifenthrin
are
variable,
depending
upon
crop
site
and
to
some
extent
upon
activity.
The
shortest
REI
is
24
hours
for
caneberries
(
mechanically
harvested),
beans
(
for
processing
only),
field
corn
(
grown
for
seed),
peas
(
for
processing
only),
sweet
corn
(
for
processing
only)
and
"
other
crops"
(
i.
e.,
meaning
crops
not
mentioned
on
the
label
with
an
otherwise
specified
REI).
Other
REIs
vary
from
4
days
to
18
days
and
generally
seem
associated
with
crops
harvested
for
the
"
fresh"
market.
Based
upon
the
conservative
estimate
of
post­
application
exposure
and
risk
described
above,
HED
believes
a
REI
of
24
hours
is
adequate
to
protect
agricultural
workers
from
post­
application
exposures
to
bifenthrin
from
the
proposed
new
uses.

9.0
Data
Needs
and
Label
Requirements
9.1
Toxicology
The
HIARC
identified
a
data
gap
pertaining
to
subchronic
inhalation
toxicity,
and
recommended
a
90­
day
inhalation
toxicity
study
be
conducted.
However,
based
on
the
acute
inhalation
toxicity
category
(
IV),
the
low
vapor
pressure
and
inhalation
MOEs
for
the
proposed
new
uses
(
870­
2200),
HED
concludes
that
it
is
appropriate
to
waive
the
requirement
for
the
28­
day
inhalation
toxicity
exposure
for
this
action
and
for
these
proposed
uses
only.

9.2
Residue
Chemistry
 
revised
Section
F
 
see
Table
4.1.5.1
 
revised
Section
B
 
see
Section
2.1
9.3
Occupational
and
Residential
Exposure
None.