May
7,
2004
MEMORANDUM
SUBJECT:
Trifluralin:
Human
Health
Risk
Assessment
PC
Code:
036101
Case
No:
0179
DP
Barcode:
296628
FROM:
Richard
Griffin,
Risk
Assessor
Reregistration
Branch
II
Health
Effects
Division
THROUGH:
Alan
Nielsen,
Branch
Senior
Scientist
Reregistration
Branch
II
Health
Effects
Division
(
7509C)

TO:
John
Pates,
Jr.
Reregistration
Branch
Special
Review
and
Reregistration
Division
(
7508W)

The
following
human
health
risk
assessment
for
trifluralin
has
been
prepared
by
the
Health
Effects
Division
for
Phase
One
of
the
Tolerance
Reassessment
Eligibility
Decision
(
TRED)
process
for
trifluralin.
Occupational
risk
assessment
for
trifluralin
is
not
addressed
in
this
document.
Aggregate
(
food
/
drinking
water
/
residential)
risk
assessment
is
based
on
the
following
memoranda:

Trifluralin:
Report
of
the
Hazard
Identification
Assessment
Review
Committee
(
R.
Fricke
memo,
5/
2/
03)

Trifluralin:
Toxicology
Disciplinary
Chapter
for
the
Tolerance
Reassessment
Eligibility
Decision
Document
(
R.
Fricke
memo,
10/
2/
03)

Trifluralin.
Product
Chemistry
Chapter
for
the
TRED
Document
(
K.
Dockter
memo,
12/
23/
03)

Trifluralin:
Residue
Chemistry
Chapter
(
R.
Griffin
memo,
3/
4/
04)

Trifluralin.
Metabolism
Assessment
Review
Committee
Briefing
Memorandum
2
(
S.
Piper
memo,
1/
6/
04)

Trifluralin:
Health
Effects
Division
(
HED)
Metabolism
Assessment
Review
Committee
(
MARC)
Decision
Document.
(
S.
Piper
memo,
3/
9/
04)

Trifluralin:
Anticipated
Residues,
Acute,
Chronic,
and
Cancer
Dietary
Exposure
Assessments
for
the
Reregistration
Eligibility
Decision
(
S.
Piper
memo,
4/
12/
04)

Trifluralin:
Drinking
Water
Assessment
for
Tolerance
Reassessment
Eligibility
Decision
(
S.
Ramasamy
memo,
12/
11/
03)

Residential
Exposure
Assessment
and
Recommendations
for
the
Tolerance
Reassessment
Evaluation
Decision
(
TRED)
Document
for
Trifluralin
(
S.
Recore
memo,
5/
6/
04)

Review
of
Trifluralin
Incident
Reports
(
J.
Blondell
memo,
5/
5/
04)
3
CONTENTS
Pg.

l.
0
SUMMARY
4
2.0
PHYSICAL
/
CHEMICAL
PROPERTIES
CHARACTERIZATION
9
3.0
TOXICOLOGY
10
3.1
Toxicity
Profile
10
3.2
FQPA
Considerations
14
3.3
Dose­
Response
Assessment
16
3.4
Endocrine
Disruption
Potential
18
4.0
DIETARY
/
RESIDENTIAL
EXPOSURE
/
RISK
19
4.1
Usage
Summary
19
4.2
Dietary
Exposure
/
Food
21
4.3
Dietary
Exposure
/
Water
26
4.4
Dietary
Risk
Estimates
31
4.5
Residential
Exposure
33
5.0
AGGREGATE
EXPOSURE
/
RISK
44
6.0
CUMULATIVE
RISK
46
8.0
HUMAN
INCIDENT
DATA
REVIEW
46
9.0
DATA
REQUIREMENTS
/
LABEL
REVISIONS
TABLES
Table
1
Nomenclature
9
Table
2
Physicochemical
Properties
9
Table
3
Acute
Toxicity
10
Table
4
Toxicology
Endpoint
Selection
16
Table
5
Registrations
for
Agricultural
Use
20
Table
6
Estimated
Concentrations
in
Water
29
Table
7
Dietary
Risk
Estimates
33
Table
8
Residential
Applicator
Systemic
Risk
36
Table
9
Residential
Applicator
Carcinogenic
Risk
38
Table
10
Post­
Application
Oral
Ingestion
41
Table
11
Post­
Application
Oral
Ingestion
Combined
41
Table
12
Residential
Post­
Application
Carcinogenic
Risk
43
Appendix
A
49
4
Appendix
B
50
Appendix
C
52
1.0
SUMMARY
Trifluralin
(
2,6­
dinitro­
N,
N­
dipropyl­
4­(
trifluoromethyl)
benzenamine)
is
a
selective,
pre­
emergence,
dinitroaniline
herbicide
registered
for
the
control
of
annual
grasses
and
certain
broadleaf
weeds.
Trifluralin
is
primarily
used
in
soybeans
and
cotton,
but
is
also
registered
for
use
on
a
variety
of
food
and
feed
crops
including:
alfalfa,
asparagus,
barley,
Brassica
vegetables,
bulb
vegetables,
celery,
citrus
fruits,
corn
(
field),
cotton,
cucurbit
vegetables,
endive,
flax,
fruiting
vegetables,
grapes,
hops,
legume
vegetables,
peanuts,
peppermint,
root
and
tuber
vegetables,
rapeseed
(
canola),
safflower,
sorghum,
spearmint,
stone
fruits,
sugarcane,
sunflower,
tree
nuts,
and
wheat.
Tolerances
range
from
0.05
ppm
to
2.0
ppm
and
adequate
enforcement
methods
are
available
for
the
determination
of
residues
in/
on
plant
commodities.
Tolerances
for
residues
of
trifluralin
in
animal
commodities
have
not
been
established.
Non­
agricultural
uses
include
turf,
ornamentals,
and
vegetable
gardens.

The
toxicity
database
is
sufficient
for
tolerance
reassessment.
Technical
trifluralin
exhibits
low
acute
toxicity
in
rats
via
the
oral,
dermal,
and
inhalation
routes
of
exposure.
In
rabbit
studies
trifluralin
is
a
slight
eye
irritant,
but
not
a
skin
irritant;
however
it
was
found
to
be
a
dermal
sensitizer
in
guinea
pigs.

Subchronic
oral
studies
in
the
rat
and
dog
show
that
the
liver
and
kidneys
appear
to
be
the
principal
target
organs.
Some
blood
effects
such
as
lower
hemoglobin
levels
and
changes
in
clinical
chemistry
are
reported.
In
a
special
urinalysis
study
in
the
male
rat,
tubular
cytoplasmic
hyaline
droplets,
increased
total
protein,
aspartate
amino­
transferase
(
AST),
and
lactate
dehydrogenase
(
LDH)
were
observed
in
the
urine.
Following
electrophoresis,
albumin,
 1­
globulin,
and
 2­
globulin
were
identified
in
the
urine.
Histopathological
findings
included
increased
incidences
of
lesions
of
the
renal
proximal
tubules,
decreased
corticomedullary
mineralization,
and
hyaline
droplets
in
the
tubular
epithelium
in
the
rat.
In
the
dog,
multifocal
cortical
tubular
cytoplasmic
pigment
deposition
was
observed.

Chronic
toxicity
to
trifluralin
was
evaluated
in
the
rat,
mouse,
and
dog.
Systemic
toxicity
in
rats
included
decreases
in
body
weight
and
body
weight
gains.
Two
12­
month
oral
toxicity
studies
were
performed
in
the
dog.
In
one
study,
increased
frequency
of
abnormal
stool,
decreased
body
weights,
decreased
body
weight
gains,
decreased
erythrocytes
and
hemoglobin,
and
increased
thrombocytes
in
males
were
observed,
while
increased
absolute
liver
weights
were
observed
in
the
other.
Trifluralin
does
not
appear
to
be
an
immunotoxicant.
There
were
no
signs
of
neurotoxicity
in
the
trifluralin
data
base.
5
In
a
rat
metabolism
study
many
non­
conjugated
(
20­
30)
and
conjugated
(
10­
20)
urinary
metabolites
were
observed
with
the
majority
present
at
1­
2%
of
the
total
urinary
radioactivity.
Four
metabolic
pathways
were
identified;
(
1)
oxidative
N­
dealkylation
of
one
or
both
propyl
groups
and
metabolites
which
were
hydroxylated
on
the
propyl
side
chain;
(
2)
reduction
of
one
or
both
nitro
groups
to
the
corresponding
amine;
(
3)
cyclization
reactions
to
give
a
variety
of
substituted
and
unsubstituted
benzimidazole
metabolites;
and
(
4)
conjugation
reactions,
including
acetylation
of
the
reduced
nitro
groups,
sulfate,
and
glucuronic
acid
conjugates.

In
developmental
toxicity
studies,
maternal
toxicity
consisted
of
decreased
body
weight
gain
and
food
consumption,
increased
liver
and
spleen
weights,
increased
incidence
of
resorptions
and
litters
with
total
resorptions
in
the
rat;
and
an
increased
number
of
abortions,
macroscopic
changes
in
the
liver
and
lungs,
and
decreased
food
consumption
in
the
rabbit.
Reduced
ossification
of
vertebrae
and
ribs
were
observed
in
both
the
rat
and
rabbit.

In
reproduction
studies
kidney
toxicity
(
acute
renal
failure,
lesions
of
renal
proximal
tubule,
increased
relative
liver)
and
uterine
atrophy
in
females
were
observed.
Offspring
toxicity
consisted
of
decreased
pup
weight
and
increased
number
of
runts.
Decreased
fetal,
neonatal,
and
litter
viability,
and
decreased
lactation
index
were
also
observed.

The
toxicity
database
is
adequate
for
FQPA
consideration.
The
concern
for
qualitative
susceptibility
is
low
even
though
some
effects
seen
in
the
rat
developmental
study
indicate
some
susceptibility.
The
HIARC
determined
that
since
the
dose
response
was
well
characterized,
the
developmental
effects
were
only
seen
in
the
presence
of
materanal
toxicity,
and
clear
NOAELs
were
established
for
developmental
and
maternal
toxicities,
the
concern
for
susceptibilty
was
low.

There
are
no
residual
uncertainties
for
pre­
and
post­
natal
toxicities
since
the
doses
selected
for
overall
risk
assessments
will
address
the
concerns
seen
in
these
studies.
Based
on
the
above
data,
no
Special
FQPA
Safety
Factor
is
needed
(
1x)
since
there
are
no
residual
uncertainties
for
pre­
and/
or
post­
natal
toxicity.

The
HIARC
reviewed
the
trifluralin
toxicity
data
and
selected
the
appropriate
studies,
endpoints,
and
dose
levels
for
human
health
risk
assessment.
An
acute
Population
Adjusted
Dose
(
aPAD)
of
1.0
mg/
kg/
day
was
established
for
females
of
child­
bearing
age
based
on
the
No
Observable
Adverse
Effect
(
NOAEL)
of
100
mg/
kg/
day
observed
in
the
rat
developmental
study.
A
chronic
Population
Adjusted
Dose
(
cPAD)
of
0.024
mg/
kg/
day
was
established
based
on
the
NOAEL
(
2.4
mg/
kg/
day)
of
a
chronic
toxicity
study
in
dogs.
The
endpoint(
s)
of
concern
is
increased
frequency
of
abnormal
stool,
decreased
body
weights,
decreased
body
weight
gains,
decreased
erythrocytes
and
hemoglobin,
and
increased
thrombocytes
in
males
at
the
6
study
LOAEL.
The
uncertainty
factor
is
100,
based
on
10x
for
inter­
species
extrapolation,
10x
intra­
species
variability,
and
1x
for
FQPA
considerations.

Risk
assessment
by
the
Margin
of
Exposure
(
MOE)
approach
for
short­
term
"
incidental"
oral
exposure
to
children
is
based
on
the
NOAEL
(
10
mg/
kg/
day)
of
the
two­
generation
reproduction
study
in
the
rat.
Risk
assessment
by
the
MOE
approach
for
short­
term
inhalation
exposure
to
residential
applicators
is
based
on
the
NOAEL
(
81
mg/
kg/
day)
of
the
30­
day
inhalation
study
in
rats.
Risk
assessment
by
the
MOE
approach
for
short­
term
dermal
exposure
is
not
quantified
based
on
no
systemic
toxicity
observed
at
the
limit
dose
in
the
dermal
toxicity
study.
Intermediate­
and
long­
term
residential
exposure
is
not
expected
for
trifluralin
and
not
assessed.
The
Agency
considers
a
Margin
of
Exposure
(
MOE)
of
100
to
be
adequately
protective
for
each
assessment.

On
January
29
and
February
27,
1986,
the
Carcinogenicity
Peer
Review
Committee
classified
trifluralin
as
a
Group
C
Carcinogen
("
possible"
human
carcinogen),
and
recommended
that,
for
the
purpose
of
risk
characterization,
a
low
dose
extrapolation
model
be
applied
to
the
experimental
animal
tumor
data
for
quantification
of
human
risk.
The
upper­
bound
potency
factor
(
Q
1*)
for
trifluralin
is
5.8
x
10­
3
(
mg/
kg/
day)­
1
based
on
male
rat
thyroid
follicular
cell
combined
adenoma,
papillary
adenoma,
cystadenoma,
and
carcinoma
tumors
(
converted
from
animals
to
humans
by
use
of
the
3/
4'
s
scaling
factor).
Extensive
testing
showed
trifluralin
is
neither
mutagenic
nor
genotoxic,
and
does
not
inhibit
the
polymerization
of
microtubules
in
mammalian
cells.

The
HED
Metabolism
Assessment
Review
Committee
(
MARC)
reviewed
trifluralin
toxicology
and
metabolism
data
(
2/
4/
04)
and
concluded
that
tolerances
for
enforcement
(
and
dietary
risk
assessment
for
plant
commodities)
should
be
based
on
trifluralin
per
se.
Also,
dietary
risk
assessment
for
ruminant
commodities
should
be
based
on
trifluralin
per
se
and
all
metabolites/
degradates
identified
as
total
radioactive
residue,
or
TRR,
in
a
ruminant
metabolism
study.
Risk
assessment
for
drinking
water
contamination
is
based
on
estimates
for
trifluralin
per
se
and
3
metabolites
identified
in
metabolism
and
photolysis
studies.
All
metabolites/
degradates
are
considered
toxicologically
similar
to
parent.

Trifluralin
is
not
acutely
toxic
and
there
is
no
expectation
that
single,
or
singleday
high­
end
exposure,
including
aggregate
exposure,
will
have
an
adverse
effect.
However,
based
on
the
toxicity
observed
in
sub­
chronic
and
chronic
studies,
trifluralin
has
been
assessed
for
the
following;
1)
acute
exposure
from
food
and
water
(
aPAD);
2)
chronic
exposure
from
food
and
water
(
cPAD);
3)
chronic
exposure
from
food
and
water
(
Q
1*);
4)
short­
term
inhalation
exposure
to
homeowner
applicators
(
MOE);
5)
combined
inhalation
and
dermal
exposure
to
homeowner
applicators
(
Q
1*);
6)
short­
term
oral
exposure
to
children
post­
application
on
turf
(
MOE);
and
7)
dermal
exposure
to
persons
7
(
golfers,
etc.)
post­
application
on
turf
(
Q
1*).

A
refined
chronic
dietary
risk
assessment
was
conducted
by
comparing
trifluralin
dietary
exposure,
due
to
food
uses
and
contaminated
drinking
water,
to
the
trifluralin
cPAD
and
secondly,
by
quantifying
carcinogenic
risk
by
the
Q
1*
approach.
The
dietary
assessment
relies
on
field
trial,
monitoring
(
PDP),
and
usage
data
(
percent
crop
treated).
Contamination
estimates
for
drinking
water
are
refined
by
PRZM­
EXAMS
modeling,
incorporating
percent
cropped
area
(
PCA)
data.
Food
consumption
data
are
from
the
USDA's
Continuing
Surveys
of
Food
Intakes
by
Individuals
(
CSFII),
1994­
1996/
1998,
combined
to
form
the
Food
Commodity
Intake
Database
(
FCID).
For
the
cPAD
dietary
risk
estimates,
the
assessment
uses
averaged
consumption
data
for
the
general
U.
S.
population
and
various
population
subgroups
and
for
carcinogenic
risk
uses
an
overall
average.
Estimated
chronic
dietary
risk
estimates
for
all
population
subgroups
are
less
than
1%
of
the
trifluralin
cPAD
(
0.005
mg/
kg/
day)
and
do
not
indicate
a
concern
for
this
route
of
exposure.
Carcinogenic
risk
for
the
general
U.
S.
population,
based
on
food
and
drinking
water,
is
10­
7
and
less
than
the
level
(
10­
6)
considered
negligible
by
the
Agency.

Trifluralin
products
are
marketed
for
homeowner
use
on
lawns,
landscape
ornamentals,
and
vegetable
gardens.
Trifluralin­
containing
products
are
also
marketed
for
use
by
professional
applicators
on
residential
turf,
on
golf
courses,
other
turf
such
as
recreational/
commercial
areas,
and
on
ornamental
plantings.
Based
on
these
uses,
trifluralin
is
assessed
for
the
residential
applicator
(
or
"
handler")
and
for
postapplication
exposure
that
may
occur
from
turf
contact.
For
residential
applicators,
all
estimated
inhalation
MOEs
are
above
the
target
MOE
of
100
and
the
carcinogenic
risk
estimate
for
typical
turf
applications
is
10­
8.

Since
a
toxicological
endpoint,
based
on
dermal
exposure,
was
not
selected
for
trifluralin,
only
post­
application
incidental
oral
ingestion
(
i.
e.,
soil,
granule,
and
hand­
tomouth
ingestion)
exposures
to
children
were
calculated.
Estimated
MOEs
for
soil,
granule,
and
hand­
to­
mouth
exposures
are
above
the
target
MOE
of
100.
However,
carcinogenic
risk
has
been
estimated,
based
on
dermal
exposure
during
golfing
or
other
activity,
over
a
lifetime
of
exposure.
These
estimates
are
less
than
10­
8
and
are
again,
considered
upper­
bound
estimates.

The
Agency
remains
concerned
about
dermal
sensitization
reactions
to
adults
and
children
who
are
exposed
to
trifluralin
in
residential
settings
and
recommends
for
labeling
to
this
effect,
on
all
products.

Acute
dietary
exposure
based
on
both
food
and
drinking
water
sources
has
been
aggregated
and
the
aPAD
risk
estimate
is
less
than
1%
for
women
of
child­
bearing
age.
Chronic
dietary
exposure
based
on
both
food
and
drinking
water
sources
has
been
aggregated
and
the
cPAD
risk
estimates
are
less
than
1%
for
the
general
U.
S.
8
population,
and
population
sub­
groups
.
Oral
exposure
estimates
for
3
specific
postapplication
activities
of
children
on
treated
turf
have
been
aggregated
to
form
an
upperbound
MOE
risk
estimate
that
is
well
above
the
target
level
of
100.

For
trifluralin,
chronic
exposure
from
foods
(
0.000022
mg/
kg/
day)
has
been
added
to
chronic
exposure
due
to
drinking
water
(
0.000008
mg/
kg/
day)
and
this
in
turn
is
added
to
estimates
of
residential
exposure
to
estimate
carcinogenic
risk.
Since
carcinogenic
risk
assessment
attempts
to
reflect
long­
term
exposure,
the
most
appropriate
exposure
estimate
would
be
based
on
the
most
common
application
method;
the
push­
type
spreader.
The
Lifetime
Average
Daily
Dose
estimated
for
this
application
method
is
negligible
(
0.0000006
mg/
kg/
day),
and
when
added
to
the
chronic
dietary
exposure
the
aggregate
carcinogenic
risk
estimate
is
2x10­
7.

Although
recognized
as
a
member
of
the
dinitroaniline
group
of
pesticides,
cumulative
risk
assessment
has
not
been
completed
for
trifluralin.
HED
has
not
initiated
a
comprehensive
review
to
determine
if
other
chemical
substances
have
a
mechanism
of
toxicity
common
to
trifluralin.

Based
on
California
incident
data
and
the
Agency's
Incident
Data
System,
it
appears
that
the
majority
of
reported
trifluralin
cases
involved
skin
and
eye
illnesses.
Poison
Control
Center
data
would
tend
to
support
these
results,
in
that
dermal
and
ocular
effects
were
some
of
the
most
common
effects
reported.
Appropriate
protective
clothing
to
protect
the
skin
and
eyes
of
applicators
is
recommended.
9
NO
2
CF
3
O
2
N
N
CH
3
C
H
3
2.0
PHYSICAL
/
CHEMICAL
PROPERTIES
Table
1
Trifluralin
Nomenclature
Chemical
structure
Common
name
Trifluralin
Molecular
Formula
C
13
H
16
F
3
N
3
O
4
Molecular
Weight
335.3
IUPAC
name
 ,
 ,
 ­
trifluroro­
2,6­
dinitro­
N,
N­
dipropyl­
p­
toluidine
CAS
name
2,6­
dinitro­
N,
N­
dipropyl­
4­(
trifluoromethyl)
benzenamine
CAS
#
1582­
09­
8
PC
Code
036101
Table
2
Physicochemical
Properties
of
Trifluralin
Parameter
Value
Reference
Melting
point/
range
42­
49

C
Trifluralin
Update
10/
29/
91
pH
5.9
±
0.1
saturated
aqueous
solution
Density
or
specific
gravity
(
22
°
C)
1.36
g/
mL
D207577,
4/
9/
97,
K.
Dockter
Water
solubility
(
25
°
C)
<
1
ppm
D207577,
4/
9/
97,
K.
Dockter
Solvent
solubility
(
25
°
C)
readily
soluble
in
organic
solvents
such
as
acetone,
acetonitrile,
chloroform,
dichloromethane,
ethyl
acetate,
and
toluene
at
>
100
g/
100
mL,
and
in
hexane
at
5­
6.7
g/
100
mL
or
methanol
at
3.3­
4
g/
100
mL
D207577,
4/
9/
97,
K.
Dockter
Vapor
pressure
(
25
°
C)
6.1
x
10­
3
Pa
D207577,
4/
9/
97,
K.
Dockter
Dissociation
constant
(
pK
a)
not
required;
does
not
dissociate
D207577,
4/
9/
97,
K.
Dockter
Octanol/
water
partition
coefficient
(
log
K
ow;
20

C)
4.83
D207577,
4/
9/
97,
K.
Dockter
Table
2
Physicochemical
Properties
of
Trifluralin
Parameter
Value
Reference
10
UV/
vis
absorption
spectrum
not
available
3.0
TOXICOLOGY
3.1
Toxicity
Profile
3.1.1
Acute
Toxicity
Acute
toxicity
studies
are
available
for
technical
trifluralin
as
well
as
manufactured
products.
Technical
trifluralin
shows
low
acute
toxicity
via
the
oral,
dermal
and
inhalation
routes
of
exposure
(
toxicity
categories
IV,
III,
and
IV,
respectively).
Technical
trifluralin
showed
some
irritation
in
the
eye
(
toxicity
category
III),
but
not
in
the
skin
(
toxicity
category
IV).
In
the
dermal
sensitization
assay
trifluralin
was
found
to
be
a
dermal
sensitizer.
Although
not
required,
an
acute
delayed
neurotoxicity
study
was
also
performed
with
negative
results.
Acute
toxicity
studies
are
summarized
in
Table
3.

Table
3
Acute
Toxicity
Guideline
No.
Study
Type
MRID
No.
Results
Toxicity
Category
870.1100
Acute
Oral
(
Rat)
00157486
(
1985)

Acceptable/
Guideline
LD50
>
5000
mg/
kg
IV
870.1200
Acute
Dermal
(
Rat)
00157482
(
1985)

Acceptable/
Guideline
LD50
>
2000
mg/
kg
III
870.1300
Acute
Inhalation
(
Rat)
00155261
(
1982)

Acceptable/
guideline
LC50
>
4660
mg/
m3,
4.66
mg/
L
IV
870.2400
Primary
Eye
Irritation
(
Rabbit)
00157483
(
1985)

Acceptable/
Guideline
Conjunctival
redness
at
24hr,
cleared
by
4
days
III
870.2500
Primary
Skin
Irritation
00157485
(
1985)

Acceptable/
Guideline
Not
an
irritant
IV
11
870.2600
Dermal
Sensitization
00157484
(
1985)

Acceptable/
Guideline
Sensitizing
agent
N/
A
3.1.2
Subchronic
Toxicity
The
subchronic
toxicity
data
base
is
complete.
Trifluralin
was
evaluated
in
rat
and
mouse
oral
studies,
in
rat
and
rabbit
dermal
studies,
in
a
rat
inhalation
study,
and
in
a
6­
month
oral
study
in
the
dog.
In
the
rat
subchronic
oral
toxicity
study,
minor
decreases
in
overall
body
weight
gains
and
food
consumption
in
males
and
females,
decreased
hemoglobin,
alkaline
phosphatase,
and
alanine
aminotransferase
in
the
males,
and
increased
absolute
and
relative
(
to
body)
liver
weights
in
males
and
females
were
observed
at
the
LOAEL
of
391
mg/
kg/
day.
In
the
mouse
subchronic
oral
toxicity
study,
no
toxicity
was
observed
at
the
highest
dose
tested
of
375
mg/
kg/
day.
In
the
dog
6­
month
oral
study,
increased
absolute
and
relative
(
to
body)
liver
weights,
liver
enlargement,
discolored
kidneys,
decreased
red
cell
indices,
increased
platelets
in
males;
and
increased
alkaline
phosphatase
were
observed
at
the
LOAEL
of
10
mg/
kg/
day.

A
21­
day
dermal
toxicity
study
in
the
rat
showed
no
systemic
toxicity
at
the
limit
dose
of
1,000
mg/
kg/
day
(
only
dose
tested).
A
31­
day
dermal
toxicity
study
in
the
rat
showed
no
systemic
toxicity
at
1,000
mg/
kg/
day;
dermal
effects
included
sub­
epidermal
inflamation
and
ulcerations
at
200
mg/
kg/
day.
A
rabbit
21­
day
dermal
toxicity
study
with
a
formulation
(
35.8%
trifluralin)
also
did
not
show
any
systemic
toxicity
at
1,000
mg/
kg/
day;
dermal
effects
observed
at
the
LOAEL
(
100
mg/
kg/
day)
included
erythema,
edema,
and/
or
scaling
and
fissuring.
The
systemic
NOAELs
(
1,000
mg/
kg/
day)
observed
in
the
dermal
toxicity
studies
are
consistent
with
the
dermal
absorption
factor
of
3%.
A
30­
day
inhalation
exposure
to
rats
at
1,000
mg/
m3
resulted
in
increased
methemoglobin
and
bilirubin,
as
well
as
dyspnea
and
ruffled
fur.

3.1.3
Chronic
Toxicity
Chronic
toxicity
to
trifluralin
was
evaluated
in
the
rat,
mouse,
and
dog.
Systemic
toxicity
in
rats
exposed
to
169/
219
mg/
kg/
day
(
males/
females)
included
decreases
in
body
weight
(
NOAEL
40/
53
mg/
kg/
day).
In
a
2­
year
mouse
study
no
systemic
toxicity
was
observed
at
the
highest
dose
tested
of
118
mg/
kg/
day.
Two
12­
month
oral
toxicity
studies
were
performed
in
the
dog.
In
one
study
increased
frequency
of
abnormal
stool,
decreased
body
weights
and
body
weight
gains,
decreased
erythrocytes
and
hemoglobin,
and
increased
thrombocytes
in
males
were
observed
at
the
LOAEL
of
40
mg/
kg/
day.
In
the
other
study
increased
absolute
liver
weights
in
males
were
observed
at
the
LOAEL
of
3.8
mg/
kg/
day.
12
3.1.4
Developmental
/
Reproductive
Toxicity
Developmental
toxicity
of
trifluralin
in
the
rat
and
rabbit,
as
well
as
three
2­
generation
reproduction
studies
were
evaluated.
In
all
of
these
studies
the
NOAEL/
LOAELs
for
parental
toxicity
were
the
same
as,
or
lower,
than
the
NOAEL/
LOAELs
for
reproductive
and
developmental
toxicity.
In
the
developmental
toxicity
studies,
maternal
toxicity
consisted
of
decreased
body
weight
gain
and
food
consumption,
increased
liver
and
spleen
weights,
increased
incidence
of
resorptions
and
litters
(
with
total
resorptions
observed
in
the
rat);
and
increased
abortions,
macroscopic
changes
in
the
liver
and
lungs,
and
decreased
food
consumption
in
the
rabbit.
Reduced
ossification
of
vertebrae
and
ribs
were
observed
in
both
the
rat
and
rabbit.
In
the
reproduction
studies
kidney
toxicity
(
acute
renal
failure,
lesions
of
renal
proximal
tubule,
increased
relative
liver
weight)
and
uterine
atrophy
in
females
were
observed.
Offspring
toxicity
consisted
of
decreased
pup
weight
including
an
increase
in
the
number
of
runts.
Decreased
fetal,
neonatal,
and
litter
viability,
and
decreased
lactation
index
were
also
observed.

3.1.5
Mutagenicity
/
Genotoxicity
Extensive
testing
showed
that
trifluralin
is
neither
mutagenic
nor
genotoxic.
There
was
no
evidence
of
mutagenicity
in
rat
dominant
lethal,
L5178Y
mouse
lymphoma,
Salmonella
typhimurium,
Saccharomyces
cerevisiae,
and
DNA
repair
assays,
nor
did
it
induce
sister
chromatid
exchange
in
Chinese
hamster
ovary
cells.
These
tests
showed
that
trifluralin
does
not
inhibit
the
polymerization
of
microtubules
in
mammalian
cells.

3.1.6
Carcinogenicity
Two
carcinogenicity
studies
by
the
National
Cancer
Institute
(
NCI)
revealed
hepatocellular
carcinomas
in
both
the
rat
and
in
the
mouse.
Subsequent
analysis
of
the
trifluralin
used
in
these
studies
showed
high
concentrations
of
nitrosamine
[
Ndinitroso
di­
n­
propylamine
NDPA]
and
the
carcinomas
were
attributed
to
this
contaminant.
Subsequent
carcinogenicity
studies
were
conducted
with
purified
trifluralin.
On
January
29
and
February
27,
1986,
the
Carcinogenicity
Peer
Review
Committee
classified
trifluralin
as
a
Group
C
Carcinogen
("
possible"
human
carcinogen),
and
recommended
that,
for
the
purpose
of
risk
characterization,
a
lowdose
extrapolation
model
be
applied
to
the
experimental
animal
tumor
data
for
quantification
of
human
risk.
The
upper­
bound
potency
factor
(
Q
1*)
for
trifluralin
is
5.8
x
10­
3
(
mg/
kg/
day)­
1
based
on
male
rat
thyroid
follicular
cell
combined
adenoma,
papillary
adenoma,
cystadenoma,
and
carcinoma
tumors
(
converted
from
animals
to
humans
by
use
of
the
3/
4'
s
scaling
factor).

3.1.7
Immunotoxicity
13
Effects
suggestive
of
immunotoxicity
include
thymic
hypoplasia
and
decreased
relative
thymus
weights
in
the
rabbit
developmental
toxicity
study
and
rat
reproduction
study,
respectively,
and
increased
spleen
weights
in
a
rat
developmental
toxicity
study.
No
other
indications
of
possible
immunotoxicity
were
observed
in
the
trifluralin
data
base.

3.1.8
Metabolism
In
a
rat
metabolism
study,
14C­
trifluralin
was
administered
by
gavage
at
300
mg/
kg/
day
to
5
rats/
sex
on
three
consecutive
days.
The
objective
of
this
study
was
to
identify
the
urinary
metabolites
of
trifluralin.
There
was
no
sex­
dependent
effect
on
metabolic
profiles.
A
minimum
of
20­
30
non­
conjugated
metabolites
and
an
additional
10­
20
conjugated
metabolites
were
present
in
the
urine,
but
no
parent
compound
was
detected.
No
single
metabolite
accounted
for
more
than
8­
10%
of
the
total
urinary
radioactivity,
and
the
majority
of
the
metabolites
were
present
at
1­
2%
of
the
total
urinary
radioactivity.
Thus,
almost
all
of
the
metabolites
were
minor
(<
5%
of
the
total
radioactive
dose).
Four
metabolic
pathways
were
identified
as
follows;
(
1)
oxidative
Ndealkylation
of
one
or
both
propyl
groups
and
metabolites
which
were
hydroxylated
on
the
propyl
side
chain;
(
2)
reduction
of
one
or
both
nitro
groups
to
the
corresponding
amine;
(
3)
cyclization
reactions
to
give
a
variety
of
substituted
and
unsubstituted
benzimidazole
metabolites;
and
(
4)
conjugation
reactions,
including
acetylation
of
the
reduced
nitro
groups,
sulfate,
and
glucuronic
acid
conjugates.

3.1.9
Kidney
Toxicity
The
kidney
appears
to
be
a
target
organ
for
trifluralin.
These
findings
are
summarized
in
a
peer
review
of
trifluralin
(
April
11,
1986)
and
include
the
following
observations;
kidney
and
bladder
tumors,
decreased
kidney
weights,
increased
BUN,
increases
in
total
protein,
aspartate
aminotransferase
and
lactate
dehydrogenase
in
the
urine.
Also,
protein
electrophoresis
of
urine
samples
showed
 1­
globulin
and
 2­
globulin,
tubular
hyaline
casts
in
the
kidneys,
minimal
cortical
tubular
epithelial
regeneration
observed
microscopically,
and
increased
incidence
of
progressive
glomerulonephritis.

A
special
rat
urinalysis
study
included
the
presence
of
tubular
cytoplasmic
hyaline
droplets,
increased
total
protein,
AST
and
LDH
in
the
urine,
albumin
 1­
globulin
and
 2­
globulin
observed
by
urine
electrophoresis,
and
increased
urinary
volume.
A
two­
generation
reproduction
study
showed
increased
incidences
of
lesions
of
the
renal
proximal
tubules,
decreased
corticomedullary
mineralization,
hyaline
droplets
in
the
tubular
epithelium,
and
acute
renal
failure.
A
developmental
toxicity
14
study
in
the
rat
demonstrated
clear
fluid
in
the
renal
pelvis,
grey
hollows
on
the
kidney
surface,
and
enlarged
kidney
with
yellow
calculi
in
the
pelvis.
In
a
chronic
dog
study,
minimal
to
slight
multifocal
cortical
tubular
cytoplasmic
pigment
deposition
was
noted
in
the
kidneys
in
males
and
females.
A
two­
week
range­
finding
study
in
the
rat
showed
urinary
triple
phosphates.

3.2
FQPA
Considerations
3.2.1
Database
Summary
Relative
to
FQPA
No
significant
toxicological
data
deficiency
has
been
identified
for
trifluralin
and
the
HED
HIARC
committee
concluded
that
the
toxicity
data
base
is
adequate
for
FQPA
considerations.
Acceptable
rabbit
and
rat
developmental
toxicity
studies
were
available
in
addition
to
two,
acceptable,
2­
generation
reproduction
studies
in
the
rat.
Also,
the
HIARC
was
able
to
conclude
that
additional
developmental
neurotoxicity
data
will
not
be
required
since
there
were
no
signs
of
neurotoxicity
in
the
trifluralin
data
base.

3.2.2
Evidence
of
Quantitative
/
Qualitative
Susceptibility
Evidence
of
increased
susceptibility:
The
HIARC
concluded
that
there
is
a
concern
for
pre­
and/
or
post­
natal
toxicity
resulting
from
exposure
to
trifluralin.
There
was
qualitative
evidence
of
increased
susceptibility
in
the
rat
developmental
toxicity
study
where
fetal
developmental
effects
(
increased
resorptions
and
wavy
ribs)
occurred
in
the
presence
of
less
severe
maternal
effects
(
decreases
in
body
weight
gain,
clinical
signs,
and
changes
in
organ
weights).
Also
qualitatively,
there
is
an
indication
of
increased
sensitivity
in
the
2­
generation
reproduction
study
in
the
rat
in
that
offspring
effects
(
decreased
fetal,
neonatal
and
litter
viability)
were
observed
at
a
dose
level
where
there
was
less
severe
maternal
toxicity
(
decreased
body
weight,
body
weight
gain
and
food
consumption).

Degree
of
Concern
Analysis
and
Residual
Uncertainties:
The
HIARC
concluded
that
concern
is
low
for
the
qualitative
susceptibility
seen
in
the
developmental
rat
study
because
the
dose
response
was
well
characterized,
the
developmental
effects
were
seen
in
the
presence
of
maternal
toxicity,
and
clear
NOAELs/
LOAELs
were
established
for
maternal
and
developmental
toxicities.
There
is
low
concern
for
the
qualitative
susceptibility
observed
in
the
rat
reproduction
study
since
the
dose­
response
was
well
characterized;
there
was
a
clear
NOAEL/
LOAEL
for
maternal
and
developmental
toxicities;
and
the
effects
were
seen
at
a
high­
dose
level
(
295/
337
mg/
kg/
day).
Offspring
viability
was
not
adversely
affected
in
two
other
2­
generation
studies
with
trifluralin
at
dose
levels
up
to
100
and
148
mg/
kg/
day.
There
are
no
residual
uncertainties
for
pre­
and
postnatal
toxicities
since
the
doses
selected
for
overall
risk
assessments
will
address
the
concerns
seen
in
these
studies.
Also,
the
HIARC
concluded
that
there
is
not
a
concern
for
developmental
neurotoxicity
resulting
from
15
exposure
to
trifluralin
since
there
were
no
signs
of
neurotoxicity
in
the
trifluralin
data
base.

3.2.3.
Special
FQPA
Safety
Factor(
s)

The
HIARC
concluded
that
the
FQPA
Safety
Factor
should
be
removed
(
equivalent
to
a
1x
Safety
Factor)
based
on
a
conclusion
of
no
concern
for
qualitative
susceptibility
seen.
The
FQPA
Safety
Factor
recommendation
by
the
HIARC
assumed
that
the
exposure
databases
(
food,
drinking
water,
and
residential)
are
complete
and
the
risk
assessment
for
each
exposure
scenario
includes
all
metabolites
and/
or
degradates
of
concern,
and
the
assessment
does
not
underestimate
the
potential
risk
for
infants
and
children.

This
criteria
has
been
met
in
the
aggregate
risk
assessment
for
trifluralin
based
on
food,
drinking
water,
and
residential
exposure.
Specifically,
the
food
exposure
assessment
is
based
on
reliable
residue,
usage,
and
consumption
data
(
including
monitoring
data)
that
does
not
underestimate
actual
trifluralin
exposure.
The
drinking
water
assessment
is
based
on
an
adequate
environmental
fate
database
for
parent
trifluralin
and
degradates,
upper­
bound
modeling
for
parent
trifluralin
and
degradates
in
water,
and
Agency
estimates
of
daily
drinking
water
consumption.
Also,
residential
risk
assessment
for
trifluralin
is
considered
an
upper­
bound
assessment
since
it
is
based
(
in
general)
on
maximum
use
rates,
the
Agency's
Residential
SOPs
(
which
tend
to
the
high
end),
and
more
recent
and
reliable
exposure
data,
including
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
data.
16
3.3
Dose
Response
Assessment
Table
4
Toxicology
Endpoint
Selection
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
FQPA
SF*
Target
MOE
Study
and
Toxicological
Effects
Acute
Dietary
(
Females
13­
50
years
of
age)
NOAEL
=
100
mg/
kg/
day
UF
=
100
Acute
RfD
=
1.0
mg/
kg/
day
FQPA
SF
=
1
aPAD
=
1.0
mg/
kg/
day
Developmental
Toxicity
Study
­
Rat
LOAEL
=
500
mg/
kg/
day
based
on
increased
total
litter
resorptions.

Acute
Dietary
(
General
population,
including
infants
and
children)
No
appropriate
single
dose
endpoint
was
selected
Chronic
Dietary
(
All
populations)
NOAEL=
2.4
mg/
kg/
day
UF
=
100
Chronic
RfD
=
0.024
mg/
kg/
day
FQPA
SF
=
1
cPAD
=
0.024
mg/
kg/
day
Chronic
Toxicity
(
capsule)
­
Dog
LOAEL
=
40
mg/
kg/
day
based
on
based
on
increased
frequency
of
abnormal
stool,
decreased
body
weights
and
body
weight
gains,
and
on
decreased
erythrocytes
and
hemoglobin
and
increased
thrombocytes
in
males
Short­
Term
Incidental
Oral
(
1­
30
days)
NOAEL=
10
mg/
kg/
day
MOE
=
100
Two­
generation
Reproduction
Study
­
Rat
LOAEL
=
32.5
mg/
kg/
day
based
on
decreased
pup
weights
in
both
generations
Intermediate­
Term
Incidental
Oral
(
1­
6
months)
NOAEL=
10
mg/
kg/
day
MOE
=
100
Special
Urinalysis
Study
­
Rat
LOAEL
=
40
mg/
kg/
day
based
on
based
on
the
presence
of
tubular
cytoplasmic
hyaline
droplets;
increased
total
protein,
AST,
and
LDH
in
the
urine;
albumin
 1­
globulin
and
 2­
globulin
observed
by
urine
electrophoresis;
and
increased
urinary
volume
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
FQPA
SF*
Target
MOE
Study
and
Toxicological
Effects
17
Short­
Term
Dermal
(
1
to
30
days)
No
quantification
required
since
there
was
no
systemic
toxicity
at
the
limit
dose
in
the
dermal
toxicity
study.
There
are
no
developmental
toxicity
concerns.
The
HIARC
also
recommends
that
the
products
containing
trifluralin
should
be
labeled
as
SENSITIZER
Intermediate­
Term
Dermal
(
1
to
6
months)
Oral
study
NOAEL
=
10
mg/
kg/
day
(
dermal
absorption
rate
=
3
%)
Residential
MOE
=
100
Occupational
MOE
=
100
Special
Urinalysis
Study
­
Rat
LOAEL
=
40
mg/
kg/
day
based
on
based
on
the
presence
of
tubular
cytoplasmic
hyaline
droplets;
increased
total
protein,
AST,
and
LDH
in
the
urine;
albumin
 1­
globulin
and
 2­
globulin
observed
by
urine
electrophoresis;
and
increased
urinary
volume
Long­
Term
Dermal
(>
6
months)
Oral
study
NOAEL=
2.4
mg/
kg/
day
(
dermal
absorption
rate
=
3
%
when
appropriate)
Residential
MOE
=
100
Occupational
MOE
=
100
Chronic
Toxicity
(
capsule)
­
Dog
LOAEL
=
40
mg/
kg/
day
based
on
based
on
increased
frequency
of
abnormal
stool,
decreased
body
weights
and
body
weight
gains,
and
on
decreased
erythrocytes
and
hemoglobin
and
increased
thrombocytes
in
males
Short­
Term
Inhalation
(
1
to
30
days)
Inhalation
study
NOAEL=
81
mg/
kg/
day
Residential
MOE
=
100
Occupational
MOE
=
100
30­
Day
Inhalation
Study
­
Rat
LOAEL
=
270
mg/
kg/
day
based
on
increased
methemoglobin
and
bilirubin
in
females
and
incidences
of
dyspnea
and
ruffled
fur
in
males
and
females
Intermediate­
Term
Inhalation
(
1
to
6
months)
Oral
study
NOAEL
=
10
mg/
kg/
day
(
inhalation
absorption
rate
=
100%)
Residential
MOE
=
100
Occupational
MOE
=
100
Special
Urinalysis
Study
­
Rat
LOAEL
=
40
mg/
kg/
day
based
on
based
on
the
presence
of
tubular
cytoplasmic
hyaline
droplets;
increased
total
protein,
AST,
and
LDH
in
the
urine;
albumin
 1­
globulin
and
 2­
globulin
observed
by
urine
electrophoresis;
and
increased
urinary
volume
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
FQPA
SF*
Target
MOE
Study
and
Toxicological
Effects
18
Long­
Term
Inhalation
(>
6
months)
Oral
study
NOAEL=
2.4
mg/
kg/
day
(
inhalation
absorption
rate
=
100%)
Residential
MOE
=
100
Occupational
MOE
=
100
Chronic
Toxicity
(
capsule)
­
Dog
LOAEL
=
40
mg/
kg/
day
based
on
based
on
increased
frequency
of
abnormal
stool,
decreased
body
weights
and
body
weight
gains,
and
on
decreased
erythrocytes
and
hemoglobin
and
increased
thrombocytes
in
males
Cancer
(
oral,
dermal,
inhalation)
Q
1*
=
5.8
X
10­
3
(
mg/
kg/
day)­
1
Group
C
("
Possible"
Human
Carcinogen)

UF
=
uncertainty
factor,
FQPA
SF
=
FQPA
safety
factor,
NOAL
=
no
observed
adverse
effect
level,
LOAEL
=
lowest
observed
adverse
effect
level,
PAD
=
population
adjusted
dose
(
a
=
acute,
c
=
chronic)
RfD
=
reference
dose,
MOE
=
margin
of
exposure,
NA
=
Not
Applicable
3.4
Endocrine
Disruption
EPA
is
required
under
the
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
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).
In
the
available
toxicity
studies
on
trifluralin,
the
effects
seen
on
the
thyroid
and
kidney
may
possibly
be
endocrine
related.
When
additional
appropriate
screening
and/
or
testing
protocols
being
considered
under
the
Agency's
EDSP
have
been
developed,
trifluralin
may
be
subjected
to
further
screening
and/
or
testing
to
better
characterize
effects
related
to
endocrine
disruption.
19
4.0
DIETARY
/
RESIDENTIAL
EXPOSURE
/
RISK
4.1
Usage
Summary
4.1.1
Agricultural
Use
Trifluralin
[
2,6­
dinitro­
N,
N­
dipropyl­
4­(
trifluoromethyl)
benzenamine]
is
a
selective,
pre­
emergence
(
to
the
weed)
herbicide
registered
for
the
control
of
annual
grasses
and
certain
broadleaf
weeds.
Trifluralin
is
one
of
the
dinitroaniline
family
of
herbicides
that
controls
weeds
by
disrupting
the
growth
process
(
preventing
cell
division)
during
germination,
but
does
not
control
established
weeds.
The
mode
of
action
(
MOA)
is
described
as
microtubule
assembly
inhibition.

Trifluralin
is
registered
for
use
on
a
wide
variety
of
food
and
feed
crops
including
soybean,
cotton,
alfalfa,
asparagus,
barley,
Brassica
vegetables,
bulb
vegetables,
celery,
citrus
fruits,
corn
(
field),
cotton,
cucurbit
vegetables,
endive,
flax,
fruiting
vegetables,
grapes,
hops,
legume
vegetables,
peanuts,
peppermint,
root
and
tuber
vegetables,
rapeseed
(
canola),
safflower,
sorghum,
spearmint,
stone
fruits,
sugarcane,
sunflower,
tree
nuts,
and
wheat.
Trifluralin
end­
use
products
for
food
and
feed
crops
include
emulsifiable
concentrates
(
EC,
36.4,
50.8%
ai)
and
a
granular
formulation
(
G,
10%
ai).
These
formulations
may
be
applied
using
ground
or
aerial
equipment,
with
the
EC
formulations
being
typically
applied
as
aqueous
dilutions.
The
application
timing
may
be
dormant,
pre­
plant,
or
pre­
emergence;
with
application
typically
followed
by
mechanical
or
water­
based
soil
incorporation.
20
Table
5
Registrations
for
Agricultural
Use
Trifluralin
Food
/
Feed
Registrations
Registrant
EPA
Reg.
No.
Label
Acceptance
Date
Formulation
Class
Product
Name
Dow
AgroSciences
LLC
62719­
97
11/
20/
01
4
lb/
gal
EC
Treflan
E.
C.
Weed
and
Grass
Preventer
62719­
131
12/
4/
01
10%
G
Treflan
TR­
10
62719­
222
2/
16/
99
3.4
lb/
gal
EC
Broadstrike
+
Treflan
62719­
250
11/
30/
01
4
lb/
gal
EC
Treflan
HFP
Industria
Prodotti
Chimici
S.
P.
A.

33660­
31
1/
15/
99
5
lb/
gal
EC
Flutrix
Five
EC
33660­
32
1/
15/
99
4
lb/
gal
EC
Flutrix
4
EC
ATT
33660­
33
1/
25/
99
4
lb/
gal
EC
Flutrix
4
EC
Agan
Chemical
Manufacturers
Ltd.

66222­
46
10/
24/
02
4
lb/
gal
EC
Triflurex
HFP
4.1.2
Residential
/
Commercial
/
Other
Use
Trifluralin
is
also
registered
for
weed
control
on
ornamentals,
field
grown
roses,
cottonwood
trees,
turfgrass,
christmas
trees,
non­
bearing
trees
and
vines,
and
rootbarrier
applications.
Sites
of
usage
include
home
lawns,
home
vegetable
gardens,
ornamental
gardens
(
including
planting
beds,
flowers,
shrubs,
and
trees)
and
other
public/
private
sites
including
golf
courses,
parkland,
bike
paths,
and
cemeteries.
For
residential
and
other
non­
agricultural
uses,
trifluralin
is
formulated
as
a
granular
(
G
0.17
­
2.0
%
ai)
and
an
emulsifiable
concentrate
liquid
(
EC
43
%
ai).
For
turf,
trifluralin
is
typically
applied
once
in
Spring
(
March/
April),
prior
to
crabgrass
germination.
The
predominant
formulation
for
the
above
uses
is
granular,
and
granular
is
the
only
formulation
used
on
turf.
However,
trifluralin
may
also
be
applied
as
a
liquid
to
ornamentals
and
vegetable
gardens.

4.1.3
Use
Estimates
Based
on
1997­
2001
data,
the
Agency
estimates
that
approximately
18,000,000
lbs
of
trifluralin
ai
is
used
per
year
for
agricultural
production
in
the
United
States.
Usage
data
available
for
this
assessment
was
limited
and
could
not
be
used
to
predict
the
general
trend
of
overall
use,
although
data
provided
by
the
registrant(
s)
indicates
a
steady
decline
in
trifluralin
use
on
the
two
major
uses,
soybean
and
cotton.
The
top
6
21
uses
include
soybean,
cotton,
wheat,
alfalfa,
sunflowers,
and
dry
beans/
peas,
and
accounts
for
93%
of
total
trifluralin
ai
applied
in
the
US.
The
label
rate
for
for
agricultural
uses
is
1
to
2
lbs
ai/
acre,
with
a
maximum
rate
of
4
lbs
ai/
acre
on
sugarcane.
However,
the
registrant
reports
that
the
typical
use
rate
is
1
lb
ai/
acre,
or
less.
The
following
are
agency
estimates
of
percent
crop
treated
for
trifluralin
registrations.
Other
crops
are
estimated
to
be
less
than
10%
treated
(
or
lack
data
for
a
reliable
estimate).

Use
Estimates:

Crop
Pounds
ai/
Year
%
Treated
Soybeans
8,200,000
15
Cotton
5,000,000
45
Sunflowers
800,000
30
Durum
Wheat
600,000
35
Dry
Beans
300,000
30
Sugarcane
200,000
10
Tomatoes
100,000
50
Beans,
Green
70,000
35
Peanuts
60,000
10
Safflower
50,000
60
Carrots
50,000
55
Peas,
Green
40,000
30
Cabbage
30,000
45
Asparagus
20,000
25
Peppers
20,000
25
Dry
Peas
20,000
15
Watermelons
20,000
15
Cantaloupes
10,000
15
Broccoli
8,000
10
Collards
3,000
35
Cauliflower
3,000
10
Greens,
Turnip
2,000
30
Greens,
Mustard
2,000
25
Spinach
2,000
10
Kale
1,000
25
Celery
1,000
10
Okra
<
500
20
Radishes
<
500
10
4.2
Dietary
Exposure
/
Food
4.2.1
Tolerance
Summary
Trifluralin
[
2,6­
dinitro­
N,
N­
dipropyl­
4­(
trifluoromethyl)
benzenamine]
tolerances
are
established
under
40
CFR
§
180.207
and
are
expressed
in
terms
of
trifluralin
per
se
in/
on
the
raw
agricultural
commodities
(
RACs)
listed
above
under
4.1.1.
Current
tolerances
range
from
0.05
ppm
to
2.0
ppm,
with
most
tolerances
established
at
the
22
enforcement
method's
"
level
of
quantitation"
(
LOQ)
of
0.05
ppm
in
plant
matrices.
At
this
time,
tolerances
for
residues
of
trifluralin
in
livestock
commodities
have
not
been
established.
Adequate
enforcement
methods
are
available
for
the
determination
of
trifluralin
per
se
residues
in/
on
plant
commodities.

4.2.2
Tolerance
Reassessment
In
general,
most
trifluralin
commodities
will
retain
their
current
tolerance
level
of
0.05
ppm
based
on
data
indicating
trifluralin
per
se
at
less
than
the
level
of
detection,
or
LOD,
in
field
trial
studies.
A
proposed,
but
not
final,
registration
for
use
on
mung
bean
sprouts
(
at
2.0
ppm)
as
a
growth
regulator
will
be
revoked,
as
well
as
a
revocation
of
tolerance
for
upland
cress.
Other
tolerance
revocations
and
recommendations
for
new
tolerances
are
made
to
conform
to
new
guidance
for
crop
group
definitions.

Of
greater
significance
however,
is
the
tolerance
increase
from
0.2
ppm
to
2.0
ppm
for
alfalfa
hay
and
the
new
tolerance
of
3.0
ppm
for
alfalfa
forage,
based
on
a
revised
use
pattern
allowing
application
during
the
growing
season.
In
the
residue
chemistry
chapter
of
the
trifluralin
Registration
Eligibility
Document
(
RED,
10/
94),
the
data
requirements
for
magnitude
of
trifluralin
residues
in
livestock
were
waived
(
R.
Perfetti
memo,
2/
4/
93)
based
on
the
low
levels
of
radioactive
residues
shown
in
the
animal
metabolism
studies
and
the
low
trifluralin
exposure
estimated
for
cattle.
The
Agency
concluded
that
tolerances
for
trifluralin
in
fat,
meat,
meat
by­
products,
and
milk
were
not
necessary
as
there
was
no
expectation
for
finite
residues
occurring
in
animal
commodities
[
40
CFR
180.6(
a)(
3)].
In
the
recent
alfalfa
field
trials,
maximum
trifluralin
residues
at
the
labeled
21­
day
PHI
were
2.2
ppm
in/
on
alfalfa
forage
and
1.6
ppm
in/
on
alfalfa
hay,
and
the
highest
average
field
trial
(
HAFT)
residues
were
2.0
ppm
in/
on
alfalfa
forage
and
1.3
ppm
in/
on
alfalfa
hay.
This
estimated
exposure
to
ruminants
from
alfalfa
is
significant
enough
to
require
additional
data
to
both
identify
metabolites
in
meat
products
and
milk,
and
to
predict
residue
levels
for
tolerance
and
risk
assessment.

4.2.3
Residue
Data
As
part
of
the
"
TRED"
process,
the
Agency
has
re­
examined
the
residue
chemistry
data
submitted
by
the
registrant(
s)
for
trifluralin.
These
data
include
studies
that
support
trifluralin's
food
uses
in
general,
including
metabolism
in
plants
and
livestock,
analytical
and
multiresidue
methods
for
enforcement,
and
studies
with
rotational
crops.
Studies
have
also
been
re­
reviewed
that
support
trifluralin
commodities
specifically,
such
as
crop
field
trials,
processing
studies,
and
storage
stability
studies.
This
data
is
presented
below
as
background
to
the
dietary
portion
of
the
risk
assessment.

4.2.4
Metabolism
in
Plants
and
Livestock
23
Plants:
The
qualitative
nature
of
trifluralin
residues
in
plants
is
adequately
understood
based
on
field
corn
and
mustard
green
metabolism
studies;
supplemented
with
carrot,
cotton,
peanut,
soybean,
and
sweet
potato
metabolism
data.
The
residue
of
concern
in
plants
is
trifluralin
per
se
and
the
current
tolerance
expression
for
plants
is
considered
adequate.
Trifluralin
was
the
predominant
residue
in
field
corn
and
mustard
greens.
Smaller
amounts
of
conjugates
C1
(
N­[
2­
Ethyl­
1­
propyl­
5­
(
trifluoromethyl)­
1H­
benzimidazol­
7­
yl]­
 ­
D­
glucopyranosylamine)
and
C2
(
N­[
2­
Ethyl­
1­
propyl­
5­(
trifluoromethyl)­
1H­
benzimidazol­
7­
yl]­
 ­
D­
glucopyranosylamine)
as
well
as
the
metabolite
TR­
4
(
 ,
 ,
 ­
trifluoro­
5­
nitro­
N4,
N4,­
dipropyltoluene­
3,4­
diamine)
were
identified
in
corn
forage.
It
was
concluded
that
conjugates
in
corn
plants
were
converted
from
nonpolar
to
polar
compounds,
and
subsequently
incorporated
into
insoluble
forms
including
cell
wall
components.

Livestock:
Trifluralin
metabolism
studies
in
ruminants
and
in
poultry
have
been
submitted
to
the
Agency
and
are
summarized
below.
Dietary
risk
assessment
is
based,
in
part,
on
the
results
of
the
ruminant
metabolism
study,
even
though
the
study
is
considered
to
be
of
low
quality
by
current
standards.
To
address
this
uncertainty
in
the
dietary
risk
assessment,
and
to
establish
the
appropriate
tolerance
expression
and
tolerance
levels
in
ruminant
commodities,
the
HED
Metabolism
Assessment
Review
Committee
(
2/
4/
04)
concluded
that
a
new
metabolism
study
in
ruminants
must
be
submitted
as
well
as
a
ruminant
feeding
study
at
1x,
3x,
and
10x
(
based
on
the
reassessed
tolerance
of
3.0
ppm
for
alfalfa
forage
the
revised
maximum
dietary
exposure
for
cattle
is
~
6.0
ppm).
In
addition,
an
analytical
method
for
determining
trifluralin
residues
in
ruminant
fat,
meat,
meat
by­
products,
and
milk
must
be
submitted
for
Agency
review.

In
the
available
ruminant
metabolism
study,
two
steers
were
dosed
with
uniformly
ring­
labeled
[
14C]
trifluralin
at
0.88
ppm
(
0.15x
the
revised
maximum
exposure)
and
8.8
ppm
(
1.5x)
in
the
diet
for
5
and
3
days,
respectively.
In
addition,
two
dairy
cows
were
dosed
with
uniformly
ring­
labeled
[
14C]
trifluralin
at
1.7
ppm
(
0.3x)
and
17
ppm
(
2.8x)
in
the
diet
for
5
and
3
consecutive
days,
respectively.
For
the
steer
dosed
with
[
14C]
trifluralin
at
levels
equivalent
to
0.15x
the
(
revised)
maximum
exposure
for
5
days,
total
radioactive
residues
(
TRR)
were
<
0.001
ppm
in
muscle,
0.004
ppm
in
fat
and
kidney,
and
0.014
ppm
in
liver.
For
the
steer
dosed
with
[
14C]
trifluralin
at
levels
equivalent
to
1.5x
the
(
revised)
maximum
exposure
for
3
days,
TRR
were
0.003
ppm
in
muscle,
0.015
ppm
in
fat,
0.048
ppm
in
kidney,
and
0.145
ppm
in
liver.
Average
TRR
values
in
milk
were
0.0016
ppm
from
the
cow
dosed
at
0.3x
and
0.011
ppm
in
milk
from
the
cow
dosed
at
2.8x.
Extracted
14C­
residues
were
fractionated
and
characterized
by
column
chromatography,
but
residues
in
milk
and
tissues
were
not
conclusively
identified.
Based
on
thin
layer
chromatography
(
TLC)
data
and
comparison
to
metabolite
fractions
identified
in
urine,
the
following
compounds
were
identified
in
milk
and
tissues:
24
Liver:
TR­
14,
TR­
5,
TR­
6,
TR­
7,
and
desethyl
TR­
14
Kidney:
TR­
42
or
TR­
44,
and
desethyl
TR­
15
Fat:
Trifluralin,
TR­
4,
TR­
6,
and
TR­
14
Milk:
Trifluralin,
TR­
2,
TR­
6,
TR­
7
and
TR­
14
It
should
be
noted
that
the
HED
Metabolism
Committee
concluded
(
2/
4/
04)
that
all
trifluralin
metabolites,
including
the
above,
must
be
considered
toxicologically
similar
to
trifluralin
per
se.

The
maximum
dietary
exposure
of
trifluralin
to
poultry
is
0.05
ppm
based
on
a
diet
consisting
of
80%
field
corn
grain
and
20%
soybean.
In
the
poultry
metabolism
study,
laying
hens
were
dosed
with
uniformly
ring
labeled
[
14C]
trifluralin
at
0.05
ppm
(
1x)
and
0.5
ppm
(
10x)
in
the
diet
for
five
consecutive
days,
or
at
50
ppm
(
1,000x)
for
ten
consecutive
days.
For
the
1x
dose
group,
TRR
were
nondetectable
in
muscle
(<
0.003
ppm),
skin/
fat
(<
0.003
ppm),
and
eggs
(<
0.001
ppm)
and
0.004
ppm
in
liver.
For
the
10x
dose
group,
TRR
were
nondetectable
(<
0.003
ppm)
in
muscle,
0.002
ppm
in
skin/
fat,
0.014
ppm
in
liver,
and

0.002
ppm
in
eggs.
For
the
1,000x
dose
group,
TRR
were
0.15
ppm
in
muscle,
0.47
ppm
in
skin/
fat,
2.49
ppm
in
liver,
and
0.032­
0.53
ppm
in
eggs.
14C­
residues
in
eggs
from
the
1,000x
dose
group
plateaued
by
8
days.
TRR
in
eggs
and
tissues
from
the
1,000x
dose
group
were
extracted
and
fractionated,
but
attempts
at
identifying
metabolites
were
unsuccessful.
However,
given
the
low
dietary
exposure
of
trifluralin
residues
to
poultry,
the
Agency
has
concluded
that
further
characterization
and
identification
of
the
residue
in
eggs
and
tissue
is
not
required.

4.2.5
Residue
Analytical
Methods
Data
Collection
/
Enforcement:
The
reregistration
requirements
for
residue
analytical
methods
are
fulfilled
for
plant
commodities.
Adequate
methods
are
available
for
data
collection
and
enforcement
of
tolerances
for
residues
of
trifluralin
per
se
in/
on
plant
commodities.
The
Pesticide
Analytical
Manual
(
PAM,
Vol.
II,
Section
180.207)
lists
four
GC
methods
(
designated
as
Methods
I,
II,
III,
and
A)
with
electron
capture
detection
(
ECD)
and
a
detection
limit
of
0.005­
0.01
ppm,
as
available
for
determination
of
trifluralin
per
se
in/
on
plant
commodities.
However,
although
the
Agency
previously
(
2/
2/
94)
waived
the
requirement
for
an
analytical
method
for
animal
commodities,
an
analytical
method
for
determining
trifluralin
residues
in
fat,
meat,
meat
byproducts,
and
milk
is
now
required
in
conjunction
with
the
required
metabolism
and
feeding
studies.

Multiresidue
Methods:
The
FDA
PESTDATA
database
(
PAM
Vol.
I,
Appendix
II,
1/
94)
indicates
that
trifluralin
is
completely
recovered
(>
80%)
using
multiresidue
method
PAM
Vol.
I
Sections
302
(
Luke
method),
303
(
Mills,
Onley,
Gaither
method)
and
304
(
Mills
Method;
Protocol
E,
fatty
foods).

4.2.6
Field
Trial
Data
("
Magnitude
of
the
Residue")
25
Plants:
Field
trials
determine
the
amount
of
residue
in
plant
commodities
at
the
time
of
harvest.
Field
trial
data
are
used
to
set
tolerance
levels
and
are
often
used
as
the
basis
for
dietary
exposure
estimates.
Overall,
adequate
field
trial
data
for
trifluralin
food/
feed
uses,
based
on
the
maximum
registered
use
patterns,
have
been
submitted
and
reviewed
by
the
Agency.
The
residue
chemistry
chapter
for
the
trifluralin
RED
(
10/
94)
noted
that,
with
a
few
exceptions,
crop
field
trial
data
were
available
to
support
the
registered
uses
of
trifluralin.
However,
a
substantial
portion
of
the
trifluralin
crop
field
trials
are
older
studies
conducted
20
to
30
years
ago
and
HED
noted
that
samples
stored
at
temperatures
above
freezing
would
be
of
particular
concern
because
storage
stability
data
indicated
the
potential
for
trifluralin
residue
instability
in
those
cases.
To
address
concerns
pertaining
to
the
storage
stability
of
trifluralin
residues,
the
Trifluralin
Reregistration
Standard,
Science
Chapter
(
7/
85)
and
the
Trifluralin
Product
and
Residue
Reregistration
Update
(
10/
91)
required
sample
storage
information
to
validate
existing
crop
field
trials.
Although
a
substantial
portion
of
the
field
trial
residue
database
for
trifluralin
is
still
considered
questionable,
the
Agency
has
determined
that
sufficient
residue
data
are
available
for
reassessment
of
trifluralin
tolerances
for
most
crops
based
on
the
following;
(
1)
the
early­
season
use
pattern
of
trifluralin
in
most
crops
results
in
residues
below
the
enforcement
method
LOQ
(
0.05
pm);
(
2)
bridging
studies
from
more
recent
field
trials
have
residue
levels
that
are
similar
to
residue
levels
in
the
earlier
field
trials;
(
3)
adequate
residue
data
are
available
for
some
crops
that
can
be
readily
translated
to
similar
uses
on
related
crops;
and
(
4)
numerous
processing
studies
conducted
at
exaggerated
rates
indicate
that
trifluralin
residues
in
various
RACs
are
likely
to
be
nondetectable
(<
0.01
ppm)
following
treatment
at
1x
the
maximum
labeled
rate.

4.2.7
Residue
Estimates
for
Risk
Assessment
The
HED
MARC
committee
met
on
2/
4/
04
and
decisions
were
made
concerning
trifluralin
residues
for
tolerance
expression
and
residues
for
risk
assessment.
For
dietary
risk
assessment,
the
residues
of
concern
are
trifluralin
per
se
in
plants;
trifluralin
per
se
and
degradates
TR­
4,
TR­
6,
and
TR­
15
in
drinking
water;
and
trifluralin
per
se
and
all
degradates
identified
as
total
radioactive
residue
(
TRR)
in
milk
and
meat(
s)
from
the
ruminant
metabolism
study.
Note
that
the
decision
to
use
TRR
is
based,
in
part,
on
the
MARC
conclusion
that
lacking
specific
toxicological
data,
trifluralin
metabolites/
degradates
are
considered
to
be
similar
to
and
not
less
toxic
than
trifluralin
parent.

Plant
Commodities:
Trifluralin
residues
were
not
detected
in
crop
field
trials
except
for
alfalfa,
beets,
cabbage,
collards,
cottonseed,
flax
seed,
green
onions,
mint,
radish,
and
one
detection
each
in
field
corn
and
mustard
greens.
Also,
monitoring
data
from
the
USDA
Pesticide
Data
Program
(
PDP,
1997­
2002)
are
available
for
the
following
commodities:
asparagus,
barley,
green
beans,
broccoli,
cantaloupe,
carrots,
celery,
cherries,
grapes,
grape
juice,
oranges,
orange
juice,
nectarines,
oats,
peaches,
26
peanut
butter,
potato,
sweet
peppers,
sweet
potato,
tomatoes,
winter
squash,
and
wheat.
Detectable
residues
of
trifluralin
were
seen
in
barley
(
3
detects,
0.005
ppm),
broccoli
(
1
detect,
0.007
ppm),
carrots
(
889
detects,
range
of
0.01­
0.21
ppm)
and
canned
tomato
(
range
of
025
ppm
to
0.002
ppm).

Livestock
Commodities:
Total
radioactive
residues
(
TRR)
in
tissue
extracts
and
milk
from
cattle
dosed
with
[
14C]
trifluralin
at
levels
equivalent
to
1.5x
to
2.8x
the
(
revised)
maximum
expected
exposure
for
3
days,
were
0.003
ppm
in
muscle,
0.015
ppm
in
fat,
0.048
ppm
in
kidney,
0.145
ppm
in
liver,
and
0.011
ppm
in
milk.
Based
on
the
conclusions
of
the
MARC
(
all
metabolites
are
considered
toxicologically
similar
to
parent),
the
TRR
measurements
were
used
for
dietary
risk
assessment.

4.2.8
Vegetable
Gardens
Trifluralin
is
currently
registered
for
use
on
home­
grown
vegetables;
with
a
recommended
rate
equal
to
4
lbs
ai/
acre.
Based
on
field
trial
and
monitoring
data,
the
Agency
expects
that
most
vegetables,
when
eaten,
would
not
have
detectable
trifluralin
residues.
However,
since
some
crops
have
demonstrated
detectable
residues,
at
application
rates
less
than
4
lbs
ai/
acre,
the
Agency
cannot
be
certain
that
residential
users
will
not
be
exposed
to
trifluralin
from
garden
usage,
or
what
that
exposure
would
be.
To
mitigate
the
uncertainty
(
and
risk)
associated
with
this
use,
HED
recommends
that
the
label
rate
for
vegetable
garden
use
not
exceed
the
label
rate
for
agricultural
uses.

4.3
Dietary
Exposure
/
Water
A
geographic
information
systems
(
GIS)
analysis
indicates
trifluralin
use
is
widespread
across
the
United
States.
The
highest
trifluralin
use
areas
(
51
to
175
lbs
of
trifluralin/
mile2)
are
found
in
the
Mississippi
embayment,
the
Red
River
basin,
northwestern
Iowa,
southwestern
Minnesota,
and
the
western
panhandle
of
Texas.
Moderate
trifluralin
use
(
11­
50
lbs
trifluralin/
mile2)
can
be
found
in
most
of
the
midwestern
corn
belt,
the
Great
Plains,
the
central
valley
of
California,
the
coastal
plains
of
North
Carolina
and
Georgia,
and
the
Mississippi
embayment.
National
Water
Quality
Assessment
(
NAWQA)
surface
and
ground
water
sampling
stations
are
located
in
the
moderate
to
high
trifluralin
use
regions.
In
these
regions,
the
maximum
trifluralin
concentrations
were
greater
than
<
0.02
ppb.
The
GIS
analysis
indicates
the
NAWQA
sampling
locations
appear
to
reflect
trifluralin
use
areas.

4.3.1
Residue
Profile
Environmental
Persistence:
Trifluralin
is
moderately
persistent
in
the
environment.
In
laboratory
soil
metabolism
studies,
trifluralin
degraded
with
half­
lives
of
116­
201
days
during
aerobic
conditions
and
25­
59
days
during
anaerobic
conditions.
27
In
field
studies,
trifluralin
dissipated
with
half­
lives
ranging
from
15­
149
days.
Trilfuralin
is
stable
to
hydrolysis
in
acidic,
neutral,
and
basic
conditions,
but
undergoes
a
rapid
degradation
by
photolysis
in
aqueous
conditions.
The
aqueous
photolysis
half­
life
for
trifluralin
is
reported
as
8.9
hours
but
photolyzes
slowly
in
soil
with
a
half­
life
of
41
days.
Mobility
/
Volatility:
Trifluralin
tends
to
bind
to
soil
with
greater
affinity,
with
Kds
ranging
from
18
for
sand
to
156
for
clay
loam.
In
the
field
dissipation
studies,
trifluralin
was
rarely
detected
below
0­
6"
soil
depth.
Trifluralin
is
expected
to
be
volatile,
with
vapor
pressure
measured
as
1.1x10­
4
Torr
(
mm
Hg).
In
the
laboratory
volatility
study
using
a
trifluralin
formulation
incorporated
in
soil,
up
to
9%
of
the
applied
radioactivity
was
detected
in
volatiles
at
30
days.
The
maximum
volatility
of
trifluralin
at
day
1
was
0.0036
µ
g/
cm2/
hour.

Environmental
Metabolites
/
Degradates:
The
major
degradates
were
reported
in
aqueous
photolysis
and
anaerobic
soil
metabolism
studies.
The
major
degradates
reported
in
aqueous
photolysis
study
include:
TR­
6
(
5­
trifluoromethyl­
3­
nitro­
1,2­
benzenediamine)
and
TR­
15
(
2­
ethyl­
7­
nitro­
5­
trifluromethylbenzimidazole).
One
major
degradate,
TR­
4
(
 ,
 ,
 ,­
trifluoro­
5­
nitro­
N4,
N4­
dipropyl­
toluene­
3,4­
diamine)
was
reported
in
the
anaerobic
soil
metabolism
study.

4.3.2
Surface
Water
Monitoring
Data:
Surface
water
monitoring
data
for
trifluralin
were
obtained
from
the
USGS/
NAWQA
data
and
USGS/
EPA
pilot
reservoir
monitoring
program
data
(
Blomquist,
et
al.
2001).
Trifluralin
was
detected
in
15%
(
2,560
detections/
17,637
sampled)
of
surface
water
samples,
generally
associated
with
watersheds
with
agricultural
use
patterns.
The
peak
surface
water
concentration
of
trifluralin
from
the
monitoring
program
is
1.74
ppb,
from
the
San
Joaquin
Study
Unit.
The
highest
timeweighted
annual
mean
concentration
is
0.618
ppb,
also
from
the
San
Joaquin
Study
Unit.
Trifluralin
was
detected
in
the
USGS/
EPA
pilot
reservoir
monitoring
study
at
the
CA,
PA,
LA,
and
SD
reservoirs.
Detection
frequencies
of
trifluralin
were
low
in
both
intake
(
2.8%)
and
treated
(
2.2%)
water.
A
maximum
of
two
detections
were
found
in
the
intake
water
samples
at
the
PA
reservoir
in
2000
and
the
LA
reservoir
in
1999.

Modeling:
Modeling
was
completed
for
parent
as
well
as
combined
trifluralin
residues
(
i.
e.,
trifluralin
and
its
major
environmental
degradation
products
greater
than
10%
of
application)
observed
in
fate
studies.
Major
degradation
products
include
5­
trifluoromethyl­
3­
nitro­
1,2­
benzene
diamine
(
TR­
6),
2­
ethyl­
7­
nitro­
5­
trifluoromethyl
benzimidazole
(
TR­
15),
and
   ­
trifluoro­
5­
nitro­
N4,
N4­
dipropyltoluene­
3,4,
diamine
(
TR­
4).

Tier
I:
Tier
I
(
FIRST)
modeling
was
conducted
using
the
application
rate
for
sugar
cane
(
4.0
lbs
ai/
A);
selected
because
it
is
the
highest
application
rate
for
all
28
trifluralin
agricultural
uses.
The
daily
peak
concentration
is
not
likely
to
exceed
66.9
ppb.
The
annual
average
concentration
of
trifluralin
is
not
likely
to
exceed
6.6
ppb.
For
combined
trifluralin
residues
(
parent
and
degradation
products),
the
peak
daily
and
annual
average
concentrations
are
not
likely
to
exceed
72.5
and
17.6
ppb,
respectively.

Tier
II:
Since
trifluralin
is
registered
on
several
crops,
Tier
II
modeling
scenarios
were
selected
to
reflect
crops
with
the
highest
use
(
soybeans,
cotton),
the
maximum
application
rate
(
sugarcane),
and
availability
of
scenarios.
GIS
analysis
indicates
the
selected
scenarios
generally
represent
moderate
to
high
trifluralin
use
(
i.
e.,

11
lbs
ai/
mi2).
Among
the
crops
modeled
(
soybean,
cotton,
canola,
tomatoes,
wheat,
carrots,
cabbage,
sugarcane,
turf
and
ornamentals),
the
maximum
environmental
concentrations
were
obtained
for
sugarcane
applied
as
a
single
aerial
application
at
4.0
lbs
ai/
acre.
Trifluralin
is
a
volatile
pesticide
(
Henry
Constant
=
1.62E­
4
atm
m3/
mole
and
vapor
pressure=
1.10E­
4
Torr)
and
has
been
detected
in
both
rain
and
air
samples
in
environmental
monitoring
programs.
Modeling
of
volatilization
rates
from
soil,
as
modeled
by
PRZM,
were
assumed
to
be
captured
through
the
aerobic
soil
metabolism
half­
life.
In
the
reservoir,
volatilization
was
simulated
using
the
Henry's
Constant
and
vapor
pressure.

For
the
sugarcane
use,
the
1
in
10
year
daily
peak
concentration
is
not
likely
to
exceed
38
ppb.
The
1
in
10
year
annual
average
concentration
is
not
likely
to
exceed
1.9
ppb.
The
30
year
annual
average
concentration
is
not
likely
to
exceed
1.3
ppb.
For
combined
trifluralin
residues,
the
concentration
is
not
likely
to
exceed
38.4
ppb
for
the
1
in
10
year
daily
peak
concentration,
2.0
ppb
for
the
1
in
10
year
annual
average
concentration,
and
1.4
ppb
for
the
30
year
annual
average
concentration.

EEC
Estimates
for
Risk
Assessment:
The
two
major
agricultural
uses
of
trifluralin
are
soybean
and
cotton.
The
Agency
estimates
that
15%
of
the
soybean
crop
and
45%
of
the
cotton
crop
is
treated
with
trifluralin.
Since
a
higher
contamination
of
drinking
water
is
expected
with
soybean
use,
the
EEC
estimates
associated
with
soybean
is
used
for
risk
assessement.
The
EECs
for
assessment
are;
1)
7.0
ppb
for
acute;
2)
0.4
ppb
for
chronic
endpoints;
and
3)
0.3
ppb
for
assessing
carcinogenic
risk
(
note
that
the
estimate
for
carcinogenic
risk
is
intended
to
reflect
lifetime
exposure).
29
Table
6
Estimated
Concentrations
/
Surface
Water
Crop
Scenarios
1
in
10
year
Peak
Concentration
(
ppb)
1
in
10
year
Annual
Daily
Average
Concentration
(
ppb)
30­
year
Annual
Daily
Average
Concentration
(
ppb)

Trifluralin
Trifluralin
+
Degradates
1
Trifluralin
Trifluralin+
Degradates
1
Trifluralin
Trifluralin+
Degradates
1
SoybeansMS
2.0lbs
a.
i./
A,
1x
6.9
7.0
0.3
0.4
0.3
0.3
CottonMS
2.0lbs
a.
i./
A,
1x
4.2
4.2
0.3
0.3
0.2
0.2
CanolaND
1.0
lb
a.
i./
A,
1x
5.8
5.8
0.6
0.6
0.5
0.5
TomatoesFL
1.0
lb
a.
i./
A,
1x
7.1
7.1
0.3
0.4
0.3
0.3
WheatND
1.0
lb
a.
i./
A,
1x
4.1
4.1
0.4
0.5
0.4
0.4
CarrotsFL
1.0
lb
a.
i./
A,
1x
7.3
7.3
0.3
0.4
0.3
0.3
CabbageFL
1.0
lb
a.
i./
A,
1x
5.8
5.8
0.3
0.3
0.2
0.2
SugarcaneLA
4.0
lb
a.
i./
A,
1x
38.1
38.4
1.9
2.0
1.3
1.4
SugarcaneLA
2.0
lb
a.
i./
A,
2x,
180
days
intervals
22.9
23.1
1.9
2.0
1.4
1.5
TurfFL
1.0
lb
a.
i./
A,
2x
56
days
intervals
16.9
17.0
0.6
0.6
0.4
0.4
TurfPA
1.0
lb
a.
i./
A,
2x
56
days
intervals
6.9
7.0
0.4
0.4
0.3
0.3
OrnamentalsOR
4.0
lb
a.
i./
A,
1x
9.4
9.4
0.4
0.4
0.3
0.4
OrnamentalsOR
2.0
lb
a.
i./
A,
2x
56
days
intervals
4.9
5.0
0.4
0.5
0.4
0.4
1
Degradates
include
TR­
4
(
 ,
 ,
 ,­
trifluoro­
5­
nitro­
N4,
N4­
dipropyl
toluene­
3,4,
diamine),
TR­
6
(
5­
trifluoromethyl­
3­
nitro­
1,2­
benzene
diamine)
and
TR­
15
(
2­
ethyl­
7­
nitro­
5­
trifluoromethylbenzimidazole)

The
maximum
daily
peak
concentration
of
trifluralin
from
PRZM/
EXAMS
simulation
(
38.1
ppb)
is
greater
than
the
highest
concentration
in
the
USGS/
NAWQA
monitoring
database
(
1.74
ppb).
However,
the
maximum
annual
average
trifluralin
30
concentration
in
surface
water
(
1.9
ppb)
is
comparable
to
time
weighted
annual
mean
concentrations
in
USGS
monitoring
studies
(
0.62
ppb).

4.3.3
Ground
Water
Monitoring
Data:
Ground
water
monitoring
data
for
trifluralin
were
obtained
from
the
USGS
NAWQA
database.
Trifluralin
was
detected
in
0.5%
of
10,083
ground
water
samples
(
49
detections)
with
a
peak
ground
water
concentration
of
0.15
ppb.

Modeling:
SCI­
GROW
is
a
screening,
or
tier
1
model
for
pesticide
concentrations
in
ground
water.
SCI­
GROW
modeling
was
based
on
sugarcane
use
because
it
represents
the
highest
application
rate
(
4.0
lbs
ai/
acre).
The
estimated
shallow
ground
water
concentration
for
trifluralin
and
trifluralin
degradates
is
not
likely
to
exceed
0.035
ppb.
Predicted
concentrations
of
trifluralin
and
combined
trifluralin
residues
in
ground
water
are
the
same
because
major
degradation
products
of
trifluralin
were
formed
through
degradation
processes
(
e.
g.,
photodegradation).
Photodegradation
is
not
considered
in
the
SCI­
GROW
model.
The
maximum
trifluralin
concentration
in
shallow
ground
water
(
0.035
ppb),
as
predicted
through
SCI­
GROW,
is
lower
than
concentrations
in
the
NAWQA
ground
water
monitoring
database
(
0.15
ppb).

4.3.4
Data
/
Model
Characterization
There
are
no
aerobic
aquatic
degradation
data
for
trifluralin.
A
default
aerobic
aquatic
degradation
half­
life
was
calculated
as
twice
the
aerobic
soil
metabolism
halflife
Submission
of
aerobic
aquatic
metabolism
data
is
expected
to
reduce
uncertainties
in
the
aquatic
metabolism
of
trifluralin.
Volatilization
of
trifluralin
was
not
directly
modeled
in
the
PRZM
scenario,
but
because
the
aerobic
soil
metabolism
halflife
represents
both
degradation
and
volatilization,
the
aerobic
soil
metabolism
half­
life
was
used
to
jointly
describe
degradation
and
volatilization
processes.

Trifluralin
residue
modeling
accounted
for
only
major
degradation
products
(>
10%
of
the
applied
radioactivity)
identified
in
fate
studies.
The
major
degradation
products
were
identified
only
in
aqueous
photolysis
and
in
anaerobic
soil
metabolism
studies.
There
were
several
degradation
products
identified
in
aerobic
soil
metabolism,
but
none
of
these
are
classified
as
major
degradation
products.
The
uncertainty
in
the
predicted
EECs
arises
from
not
including
the
minor
degradation
products
(<
10%
of
applied
radioactivity)
in
the
drinking
water
exposure
assessment.
Also,
there
may
be
uncertainty
in
the
predicted
EECs
due
to
the
application
timing
used
for
modeling
since
EECs
are
expected
to
vary
according
to
the
date
of
application.
However,
model
simulations
are
based
on
a
fixed
application
date
of
March
1st.
Modeling
was
conducted
using
the
maximum
application
rate
for
specific
crops.
The
use
of
typical
application
rates
on
specific
crops
is
expected
to
lower
predicted
concentrations.
31
Tier
II
EECs
were
adjusted
for
percent
cropped
area
(
PCA)
in
the
watershed.
For
all
crops
modeled
except
soybean,
cotton
and
wheat,
a
default
percent
cropped
area
factor
of
0.87
was
used.
The
crop
specific
PCA
factors
were
available
for
soybean
(
0.46),
cotton
(
0.2)
and
wheat
(
0.56).
If
specific
PCA
factors
for
other
crops,
such
as
canola,
tomatoes,
carrots,
cabbage,
sugarcane,
turf,
and
ornamentals
were
available,
it
is
likely
to
lower
the
predicted
EECs
for
those
specific
crops.

No
monitoring
data
for
trifluralin
degradation
products
are
available
to
allow
for
a
comparison
of
predicted
concentrations
and
actual
concentrations
of
combined
trifluralin
residues.
Although
the
NAWQA
monitoring
stations
appear
to
be
located
(
based
on
county
level
data)
in
most
of
the
high
trifluralin
use
areas,
the
study
design
of
NAWQA
was
not
targeted
to
account
for
all
trifluralin
use
areas,
timing
of
application
and
other
factors
which
may
more
accurately
represent
spatially
and
temporally
dependent
variables
influencing
runoff
vulnerability.

4.3.5
Office
of
Water
Health
Advisory
Values
Based
on
the
2002
drinking
water
standards
and
Health
Advisories
(
HA),
no
MCL/
MCLG
is
available
for
trifluralin.
The
one­
day
and
10­
day
health
advisories
for
a
10
kilogram
child
are
80
ppb.
The
Lifetime
HA
is
the
concentration
of
a
chemical
in
drinking
water
that
is
not
expected
to
cause
any
adverse
non­
carcinogenic
effects
for
a
lifetime
exposure.
The
Lifetime
HA
for
trifluralin
is
5
ppb
and
is
based
on
the
exposure
of
a
70
kg
adult
consuming
2
liters
of
water,
per
day.
The
Drinking
Water
Equivalent
Level
(
DWEL)
is
reported
as
300
ppb.
DWEL
is
a
lifetime
exposure
concentration
protective
of
adverse,
non­
carcinogenic
health
effects
that
assumes
all
of
the
exposure
to
a
contaminant
is
from
drinking
water.
The
Cancer
Risk
Health
Advisory
is
reported
as
500
ppb
based
on
carcinogenic
risk
at
the
level
of
10­
4.

4.4
Dietary
(
Food
and
Drinking
Water)
Risk
Estimates
Acute
Dietary
Risk:
An
acute
dietary
assessment
was
not
conducted
for
the
general
U.
S.
population
or
other
population
sub­
groups
because
there
was
no
appropriate
single
dose
endpoint.
The
upper­
bound
risk
estimate
for
females
13­
49
years
of
age
(
designated
in
the
HIARC
report)
is
less
than
1%
of
the
aPAD
at
the
99.9th
exposure
percentile.
Results
of
the
Lifeline
analysis
are
fully
consistent
with
DEEMFCID
results
(<
1%
aPAD).

Chronic
Dietary
Risk:
Based
on
the
conclusions
of
the
HED
HIARC
committee,
dietary
risk
for
trifluralin
is
assessed
by
comparing
chronic
dietary
exposure
estimates
(
in
mg/
kg/
day)
to
the
trifluralin
cPAD,
with
dietary
risk
expressed
as
a
percent
of
the
cPAD.
The
cPAD
is
the
chronic
Population
Adjusted
Dose;
the
chronic
Reference
Dose
(
0.024
mg/
kg/
day)
modified
by
the
FQPA
safety
factor.
The
trifluralin
cPAD
is
0.024
mg/
kg/
day
based
on
a
RfD
of
0.024
mg/
kg/
day
(
see
Section
3.3.1,
Endpoint
32
Selection
Discussion),
and
incorporating
the
FQPA
safety
factor
of
1x
(
no
special
factor)
for
the
overall
U.
S.
population
or
any
population
sub­
groups.

The
cPAD
method
of
risk
assessment
is
applicable
to
the
oral
exposure
route
and
is
used
to
assess
both
food
and
drinking
water
exposure.
Exposure
estimates
that
are
less
than
100%
of
the
cPAD
indicate
a
determination
of
safety
can
be
concluded.
The
following
summarizes
the
Agency's
current
method
for
determining
exposure
due
to
use
on
food
commodities.
Chronic
dietary
risk
is
estimated
for
the
general
U.
S.
population
and
population
sub­
groups
defined
by
sex,
age,
region,
and
ethnicity.
Durations
of
chronic
exposure
vary
from
one­
year
as
represented
by
"
all
infants",
to
lifetime
exposure
as
represented
by
the
general
U.
S.
population,
which
combines
all
population
subgroups
to
form
a
mean
exposure
value.
It
should
be
noted
that
all
parameters
of
chronic
dietary
exposure
estimates
are
averaged
values
(
i.
e.
average
food
consumption,
average
residue,
etc.).
The
assessment
is
based
on
PDP,
field
trial
and
processing
data.
Dietary
exposure
estimates
are
also
factored
by
the
estimated
weighted
average
usage,
or
"
percent
crop
treated"
data.

Carcinogenic
dietary
risk
is
based
on
the
chronic
exposure
estimate
for
the
general
U.
S.
population
derived
from
the
same
residue,
percent
use,
and
averaged
consumption
data
summarized
above
for
the
cPAD
method.
Note
that
the
consumption
data
for
the
general
U.
S.
population
represents
all
age
groups,
all
geographic
areas,
all
ethnic
groups,
and
incorporates
reports
of
no
consumption
(
non­
user).
The
final
risk
estimate
is
calculated
by
multiplying
the
average
U.
S.
exposure
estimate
by
the
trifluralin
upper­
bound
potency
factor,
or
Q
1*.
The
risk
estimate
represents
the
probability
of
"
excess"
cancers
attributable
to
trifluralin.
In
general,
the
Agency
considers
carcinogenic
risk
estimates
of
10­
6,
or
less,
to
be
negligible.

Consumption
Data
/
DEEM
/
Lifeline:
The
trifluralin
chronic
dietary
exposure
assessment
was
conducted
using
the
Dietary
Exposure
Evaluation
Model
software
with
the
Food
Commodity
Intake
Database
(
DEEM­
FCID
 
,
Version
1.3)
which
incorporates
consumption
data
from
the
USDA
Continuing
Surveys
of
Food
Intakes
by
Individuals
(
CSFII),
1994­
1996
and
1998.
The
1994­
96,
98
data
are
based
on
the
reported
consumption
of
more
than
20,000
individuals
over
two
non­
consecutive
survey
days.
Foods
"
as
consumed"
are
linked
to
EPA­
defined
food
commodities
using
publicly
available
recipe
translation
files
(
developed
jointly
by
USDA/
ARS
and
EPA).
For
chronic
exposure
assessment,
consumption
data
are
averaged
for
the
entire
U.
S.
population
and
within
population
sub­
groups,
but
are
retained
as
individual
consumption
"
events"
for
acute
exposure
assessment.
Based
on
analysis
of
the
1994­
96,
98
CSFII
consumption
data
which
took
into
account
dietary
patterns
and
survey
respondents,
HED
concluded
that
it
is
appropriate
to
report
risk
for
the
following
population
subgroups:
the
general
U.
S.
population,
all
infants
(<
1
year
old),
children
1­
2,
children
3­
5,
children
6­
12,
youth
13­
19,
adults
20­
49,
females
13­
49,
and
adults
50+
years
old.
Exposure
estimates
(
Table
5)
are
expressed
in
mg/
kg
body
weight/
day
and
33
as
a
percent
of
the
cPAD.

Lifeline
Model:
Dietary
exposure
estimates
were
also
conducted
using
the
Lifeline
 
model
(
Version
2.0)
which
is
also
based,
in
part,
on
CSFII,
1994
­
1996
and
1998
consumption
data
with
FCID.
Lifeline
 
models
individual
dietary
exposures
over
a
season
by
selecting
a
new
CSFII
diary
each
day
from
a
set
of
similar
individuals,
based
on
age
and
season
attributes.
The
Lifeline
chronic
dietary
exposure
estimate
is
based
on
an
average
daily
exposure
from
a
profile
of
1,000
individuals
over
a
one
year
period.
Further
information
regarding
the
Lifeline
 
model
can
be
found
at
the
following
web
site:
www.
theLifeline
 
group.
org.
Chronic
dietary
risk
estimates
for
all
population
sub­
groups
are
less
than
1%
of
the
trifluralin
cPAD
(
0.024
mg/
kg/
day)
and
concern
for
this
route
of
exposure
is
not
indicated.
Carcinogenic
risk
is
estimated
to
be
10­
7
for
the
general
U.
S.
population.

Table
7
Dietary
Risk
Estimates
/
Food
and
Water
Combined
Acute
/
Chronic
Dietary
Exposure
and
Risk
Estimates
Population
Subgroup
PAD,
mg/
kg/
day
DEEM­
FCID
Lifeline
Exposure,
mg/
kg/
day
%
PAD
Exposure,
mg/
kg/
day
%
PAD
Acute
Dietary
Estimates
(
99.9th
Percentile
of
Exposure)

Females
13­
49
yrs
1
0.000262
0.000311
<
1
Chronic
PAD
Dietary
Estimates
U.
S.
Population
0.024
0.000030
<
1
0.000019
<
1
All
infants
(<
1
yr)
0.024
0.000062
<
1
0.000033
<
1
Children
1­
2
yrs
0.024
0.000073
<
1
0.000051
<
1
Children
3­
5
yrs
0.024
0.000062
<
1
0.000039
<
1
Children
6­
12
yrs
0.024
0.000041
<
1
0.000024
<
1
Youth
13­
19
yrs
0.024
0.000025
<
1
0.000016
<
1
Adults
20­
49
yrs
0.024
0.000025
<
1
0.000017
<
1
Adults
50+
yrs
0.024
0.000025
<
1
0.000017
<
1
Females
13­
49
yrs
0.024
0.000024
<
1
0.000017
<
1
Carcinogenic
Risk
Estimate
U.
S.
Population
Q
1*
0.0058
0.000028
10­
7
0.000019
10­
7
4.5
Residential
Exposure
/
Risk
Residential
risk
assessment
considers
all
potential
pesticide
exposure,
other
than
exposure
due
to
residues
in
foods
or
in
drinking
water.
Exposure
may
occur
during
and
after
application
at
homes;
or
after
applications
at
golf
courses,
parks,
schools,
etc.
Each
route
of
exposure
(
oral,
dermal,
inhalation)
is
assessed,
where
34
appropriate,
and
risk
is
expressed
as
a
Margin
of
Exposure
(
MOE),
which
is
the
ratio
of
estimated
exposure
to
an
appropriate
No­
Observed­
Adverse­
Effect­
Level
(
NOAEL)
dose.
For
trifluralin,
carcinogenic
risk
is
also
estimated
by
the
Q
1*
approach.

Trifluralin
products
are
marketed
for
homeowner
use
on
residential
lawns,
landscape
ornamentals,
trees,
and
vegetable
gardens.
Trifluralin
containing
products
are
also
marketed
for
use
by
professional
applicators
(
Pest
Control
Operators,
or
PCOs)
on
residential
turf,
on
golf
courses,
other
turf
such
as
recreational/
commercial
areas,
and
on
ornamental
plantings.
Based
on
these
uses,
trifluralin
is
assessed
for
the
residential
applicator
(
or
"
handler"),
for
children's
post­
application
oral
exposure
that
may
occur
from
turf
contact,
and
for
post­
application
dermal
contact.

4.5.1
Residential
Applicator
/
Systemic
Risk
(
MOE
Approach)

Homeowners
(
or
others)
may
be
exposed
to
trifluralin
while
treating
their
lawns,
ornamentals,
or
vegetable
gardens.
Trifluralin
may
be
in
a
granular
or
liquid
form,
and
applied
at
various
rates
from
3
lbs
ai/
A
on
turf,
to
20
lbs
ai/
A
on
ornamental
beds.
HED
has
developed
residential
exposure
scenarios
for
trifluralin
based
on
the
use
sites,
formulations,
application
rates,
and
the
various
equipment
that
may
be
used
during
applications.
The
quantitative
exposure/
risk
assessment
developed
for
residential
handlers
is
based
on
these
scenarios:

Granular
formulation:
mix/
load/
apply
with
belly
grinder
spreader
Granular
formulation:
mix/
load/
apply
with
push­
type
spreader
Granular
formulation:
mix/
load/
apply
with
shaker
can
(
by
hand)
Liquid
formulation:
mix/
load/
apply
with
hose­
end
sprayer
Liquid
formulation:
mix/
load/
apply
with
low
pressure
handwand
Liquid
formulation:
mix/
load/
apply
with
backpack
sprayer
Other:
applying
trifluralin
impregnated
fabric
squares
to
soil
Residential
risk
estimates
are
also
based
on
estimates
(
and
assumptions)
regarding
the
body
weight
of
a
typical
homeowner/
applicator,
the
area
treated
per
application,
and
the
seasonal
duration
(
in
days)
of
exposure.
Note
also
that
residential
applicators
are
assumed
to
complete
all
elements
of
an
application
(
mix/
load/
apply)
without
use
of
protective
equipment
(
assessments
are
based
on
an
assumption
that
individuals
will
be
wearing
short­
sleeved
shirts
and
short
pants).

Trifluralin­
specific
data
to
assess
the
above
exposure
scenarios
were
not
submitted
to
the
Agency
in
support
of
reregistration.
Instead,
exposure
estimates
for
these
scenarios
are
taken
from
the
Pesticide
Handlers
Exposure
Database
(
PHED,
Version
1.1
August
1998)
which
is
routinely
used
to
assess
handler
exposures
for
regulatory
actions
when
chemical­
specific
monitoring
data
are
not
available.
In
addition
to
PHED
data,
this
risk
assessment
relies
on
data
from
the
Outdoor
35
Residential
Exposure
Task
Force
(
ORETF)
and
proprietary
studies
(
see
appendix
for
study
descriptions).

Exposure
Factors
/
Other
Estimates:
For
risk
assessment,
the
average
body
weight
of
an
adult
applicator
is
set
at
70
kg
and
represents
the
general
adult
population
(
effects
identified
in
the
selected
toxicity
studies
were
not
sex
specific).
Other
factors
used
for
the
trifluralin
assessment
are
taken
from
the
HED
Science
Advisory
Committee
Policy
12:
Recommended
Revisions
To
The
Standard
Operating
Procedures
For
Residential
Exposure
Assessment
(
2/
22/
01)
and
include
the
amount/
area
treated
estimates
of:
1)
5
gallons
of
liquid
formulation
per
day
when
using
a
low­
pressure
handwand,
or
a
backpack
sprayer;
2)
1,000
ft2
for
ornamental
and
vegetable
garden
treatments,
using
liquid
formulations,
with
a
hose­
end
sprayer;
3)
0.5
acres
for
lawn
and
ornamental
treatments,
using
granular
formulations,
with
a
bellygrinder
spreader
or
push­
type
spreader;
4)
1,000
ft2
for
granular
spot
treatments
to
lawns
with
a
belly
grinder,
spoon,
measuring
scoop,
shaker
can,
or
by
hand;
and
5)
1,000
ft2
for
granular
treatments
to
flower
or
vegetable
gardens
with
a
belly
grinder,
spoon,
measuring
scoop,
shaker
can,
or
by
hand.

The
seasonal
duration
of
trifluralin
exposure
to
homeowner
applicators
is
thought
to
be
a
day,
or
a
few
days,
but
well
within
the
30
day
duration
defined
as
shortterm
for
the
purposes
of
risk
assessment.
Dermal
exposure
at
the
time
of
application
is
typically
assessed
for
pesticides,
but
in
the
case
of
trifluralin
systemic
toxicity
was
not
observed
at
the
limit
dose
of
1,000
mg/
kg
in
the
dermal
toxicity
study.
However,
inhalation
exposure
and
associated
systemic
toxicity
is
assessed
by
comparing
inhalation
exposure
estimates
to
the
NOAEL
(
81
mg/
kg/
day)
seen
in
the
30­
day
rat
inhalation
study.
A
margin
of
exposure
of
100
(
or
more)
is
considered
adequately
protective
for
this
route
of
exposure.

MOE
estimates
for
applicator
exposure
scenarios
are
presented
in
Table
6
below.
36
Table
8.
Residential
Applicator
Short­
Term
Inhalation
Exposure
/
Risk
Exposure
Scenario
(
Scenario
#)
Use
Site
Inhalation
Unit
Exposure
(

g/
lb
ai)
a
Application
Rateb
Amount
Used
or
Area
Treated
per
Dayc
Daily
Inhalation
Dose
(
mg/
day/
day)
d
Inhalation
MOEe
MIXER/
LOADER/
APPLICATOR
EXPOSURE
Loading/
applying
granulars
with
a
belly
grinder
(
1)
ornamental
(
pre­
plant)
62
20
lbs
ai/
acre
0.023
acres
4.10e­
03
2.00e+
05
ornamental
(

postplant
4.0
lbs
ai/
acre
0.023
acres
8.20e­
05
9.90e+
05
turf
3.0
lbs
ai/
acre
0.5
acres
1.30e­
03
6.10e+
04
vegetable
gardens
4.1
lbs
ai/
acre
0.023
acres
8.30e­
05
9.70e+
05
Loading/
applying
granulars
with
a
push­
type
spreader
(
2)
ornamental
(
pre­
plant)
0.88
20
lbs
ai/
acre
0.023
acres
5.80e­
06
1.40e+
07
ornamental
(

postplant
4.0
lbs
ai/
acre
0.023
acres
1.20e­
06
7.00e+
07
turf
3.0
lbs
ai/
acre
0.5
acres
1.90e­
05
4.30e+
06
vegetable
gardens
4.1
lbs
ai/
acre
0.023
acres
1.20e­
06
6.90e+
07
Loading/
applying
granulars
using
a
spoon,
measuring
scoop,
shaker
can,
or
by
hand(
3)
ornamental
(
pre­
plant)
45
20
lbs
ai/
acre
0.023
acres
3.00e­
04
2.70e+
05
ornamental
(

postplant
4.0
lbs
ai/
acre
0.023
acres
5.90e­
05
1.40e+
07
turf
3.0
lbs
ai/
acre
0.023
acres
4.40e­
05
1.80e+
06
vegetable
gardens
4.1
lbs
ai/
acre
0.023
acres
6.00e­
05
1.30e+
06
rose
bushes
0.00043
lbs
ai/
bush
50
bushes
1.40e­
05
5.90e+
06
Mixing/
loading/
applying
liquids
with
a
hose­
end
sprayer
(
4)
flowers,
trees
and
shrubs
1.5
4.1
lbs
ai/
acre
0.023
acres
2.00e­
06
4.00e+
07
vegetable
gardens
4.1
lbs
ai/
acre
0.023
acres
2.00e­
06
4.00e+
07
Mixing/
loading/
applying
liquids
with
low
pressure
hand
wand
(
5)
flowers,
trees,
and
shrubs
3.8
0.047
lbs
ai/
gallon
5
gallons
1.30e­
05
6.30e+
06
vegetable
gardens
0.047
lbs
ai/
gallon
5
gallons
1.30e­
05
6.30e+
06
Mixing/
loading/
applying
liquids
with
back
pack
sprayer
(
6)
flowers,
trees,
and
shrubs
30
0.047
lbs
ai/
gallon
5
gallons
1.00e­
04
8.00e+
05
vegetable
gardens
0.047
lbs
ai/
gallon
5
gallons
1.00e­
04
8.00e+
05
Applying
trifluralin
impregnated
fabric
squares
to
soil
(
7)
No
data
are
available
for
this
scenario.
37
Footnotes
below
38
Footnotes:

a
Inhalation
unit
exposure
values
from
PHED
represent
no
respirator.
7
b
Application
Rates
are
based
on
the
maximum
application
rates
listed
on
the
trifluralin
labels.
c
Amount
handled
per
day
are
from
EPA
estimates
of
acres
treated,
or
square
feet
treated,
in
a
single
day
based
on
the
application
method.
For
ready
to
use
formulations,
the
whole
container
is
assumed
to
be
used
in
one
day.
d
Daily
Inhalation
dose
(
mg/
kg/
day)
=
(
Inhalation
Unit
Exposure
(

g/
lb
ai)
x
(
1mg/
1000

g)
Conversion
Factor
x
Application
Rate
(
lb
ai/
A
or
lb
ai/
gal
or
lb
ai/
bush)
x
Area
Treated
per
day
(
acres,
gallons,
or
bushes))/
body
weight
(
70
kg).
e
Short­
term
Inhalation
MOE
=
Inhalation
NOAEL
(
81
mg/
kg/
day)/
Daily
Inhalation
Dose
(
mg/
kg/
day).

4.5.2
Residential
Applicator
/
Carcinogenic
Risk
(
Q
1*
Approach)

Trifluralin
has
been
classified
as
a
Category
C
("
possible")
human
carcinogen
with
carcinogenic
risk
quantified
by
the
Q
1*
approach.
The
Agency
considers
all
exposure
to
trifluralin,
including
the
dermal
and
inhalation
exposure
expected
for
homeowners,
to
have
an
associated
carcinogenic
risk.
Carcinogenic
risk
for
homeowner
applicators
is
assessed
based
on
the
rates
and
application
methods
outlined
above.
An
(
upper­
end)
assumption
is
made
that
the
users
assessed
will
apply
trifluralin
each
season,
as
labeled,
for
50
years
of
their
life.
Specific
methods
(
or
scenarios)
of
application
(
spreader,
sprayer,
etc.)
are
assessed
to
demonstrate
the
full
range
of
exposure
due
to
method
and
area
treated,
although
users
are
not
expected
to
use
one
method
for
50
years.
Carcinogenic
risk
for
homeowner
applicators
is
assessed
by
combining
dermal
exposure
(
adjusted
for
an
estimated
3%
absorption
based
on
ethalfluralin
data)
and
inhalation
exposure
(
100%
absorption),
calculating
this
exposure
on
a
per
day
basis
("
Lifetime
Average
Daily
Dose",
in
mg/
kg/
day),
and
then
quantifying
risk
by
multiplying
the
upper­
bound
carcinogenic
potency
factor
(
Q
1*)
of
5.8
x
10­
3
(
mg/
kg/
day)­
1
by
the
combined
exposure
estimate.

For
carcinogenic
risk
assessments,
the
Agency
considers
the
typical
application
rate
for
a
given
use
site,
if
known.
The
typical
application
rate
is
not
known
for
most
trifluralin
applications
in
residential
settings,
therefore,
with
one
exception,
the
maximum
labeled
application
rate
was
used
for
carcinogenic
risk
assessment.
However,
since
the
labeled
rate
for
established
ornamentals
is
2
to
4
lbs
ai/
A,
the
Agency
has
used
3
lbs
ai/
A
for
the
assessment
of
this
scenario.
Table
9.
Residential
Applicator
Carcinogenic
Risk
Exposure
Scenario
(
Scenario
#)
Use
Site
Application
Rate
a
Area
Treated
Dermal
Unit
Exposure
(
mg/
lb
ai)
Inhalation
Unit
Exposure
(
ug/
lb
ai)
Residential
Handler
Treatments
/
Year
b
Daily
Total
Dose
(
mg/
kg/
day)

c
Residential
Handler
Total
LADD
(
mg/
kg/
day)
d
Residential
Handler
Cancer
Risk
e
Combined
Residential
Handler
Cancer
Riskf
MIXER/
LOADER/
APPLICATOR
EXPOSURE
Loading/
applying
granulars
with
a
belly
grinder
(
1)
ornamental
(
pre)
20
lb
ai/
acre
0.023
acres
110
62
1
0.022
4.4E­
05
2.5E­
07
8.85E­
07
ornamental
(
post)
3
lb
ai/
acre
0.023
acres
110
62
1
0.0033
6.5E­
06
3.8E­
08
turf
3
lb
ai/
acre
0.5
acres
110
62
2
0.024
9.4E­
05
5.4E­
07
vegetable
gardens
4.1
lb
ai/
acre
0.023
acres
110
62
1
0.0045
8.8E­
06
5.1E­
08
Loading/
applying
granulars
with
a
push
type
spreader
(
2)
ornamental
(
pre)
20
lb
ai/
acre
0.023
acres
0.67
0.88
1
0.00014
2.7E­
07
1.6E­
09
5.52E­
09
ornamental
(
post)
3
lb
ai/
acre
0.023
acres
0.67
0.88
1
0.000021
4.0E­
08
2.3E­
10
turf
3
lb
ai/
acre
0.5
acres
0.67
0.88
2
0.00015
5.9E­
07
3.4E­
09
vegetable
gardens
4.1
lb
ai/
acre
0.023
acres
0.67
0.88
1
0.000028
5.5E­
08
3.2E­
10
Loading/
applying
granulars
using
a
spoon,
measuring
scoop,
shaker
can,
or
by
hand(
3)
ornamental
(
pre)
20
lb
ai/
acre
0.023
acres
3.5
45
1
0.00099
1.9E­
06
1.1E­
08
1.68E­
08
ornamental
(
post)
3
lb
ai/
acre
0.023
acres
3.5
45
1
0.00015
2.9E­
07
1.7E­
09
turf
3
lb
ai/
acre
0.023
acres
3.5
45
2
0.000049
1.9E­
07
1.1E­
09
vegetable
gardens
4.1
lb
ai/
acre
0.023
acres
3.5
45
1
0.0002
3.9E­
07
2.3E­
09
Mixing/
loading/
applying
liquids
with
a
hose­
end
sprayer
(
4)
flowers,
trees,
shrubs,

vegetable
gardens
4.1
lb
ai/
acre
0.023
acres
39
1.5
5
0.0016
1.5E­
05
8.9E­
08
Mixing/
loading/
applying
liquids
with
low
pressure
hand
wand
(
5)
flowers,
trees,
shrubs,

vegetable
gardens
0.047
lb
ai/
gal
5
gallons
56
3.8
5
0.0057
5.5E­
05
3.2E­
07
Mixing/
loading/
applying
liquids
with
back
pack
sprayer
(
6)
flowers,
trees,
shrubs,

vegetable
gardens
0.047
lb
ai/
gal
5
gallons
100
30
5
0.01
1.0E­
04
5.8E­
07
Applying
trifluralin
impregnated
fabric
squares
to
soil
(
7)
No
data
are
available
for
this
scenario.
40
a
Maximum
application
rates
were
utilized
for
all
use
sites
except
for
the
granular,
post­
plant
application.
The
label
rates
for
this
use
ranged
from
2
to
4
lb
ai/
acre
so
the
average
rate
of
3
lb
ai/
acre
was
utilized
for
the
cancer
assessment.
b
The
number
of
exposures
per
year
are
based
on
the
label
recommendations.
c
Total
Daily
Dose
(
mg/
kg/
day)
=
Daily
Dermal
Dose
(
mg/
kg/
day)
*
Dermal
Absorption
(
3%)
+
Daily
Inhalation
Dose
(
mg/
kg/
day).
d
LADD
(
mg/
kg/
day)
=
Total
Daily
Dose
(
mg/
kg/
day)
*
(#
days
of
exposure
per
year/
365
days/
year)
*
(
50
years
exposed/
70
years
in
a
lifetime).
e
Cancer
Risk
=
LADD
(
mg/
kg/
day)
*
Q1*
(
0.0058)
f
Combined
Cancer
Risk
by
Equipment
Type
=
Cancer
risks
for
each
crop
in
the
equipment
scenario
added
to
one
another.

4.5.3
Residential
Post­
Application
/
Systemic
Risk
(
MOE
Approach)

Exposure
to
trifluralin
occurs
in
the
residential
environment
following
applications
by
professionals,
or
non­
professionals,
to
lawns
and
ornamentals.
Exposure
to
trifluralin
also
occurs
following
applications
by
professionals
to
private
or
public
areas
such
as
golf
courses,
parkland,
etc.
Although
the
type
of
site
that
trifluralin
may
be
used
on
varies
from
golf
courses
to
ornamental
gardens,
the
scenario
chosen
for
risk
assessment
(
residential
turf
use)
represents
what
the
Agency
considers
the
likely
upper­
end
of
possible
exposure
and
risk.
For
this
assessment,
children
are
the
population
group
of
concern.
Since
systemic
toxicity
was
not
observed
in
a
dermal
toxicity
study,
up
to
a
dose
level
of
1,000
mg/
kg/
day,
the
risk
scenario
addressed
in
this
assessment
is
the
possible
oral
exposure
of
small
children
from
treated
turf,
or
from
treated
soil
(
i.
e.,
soil
ingestion,
granule
ingestion,
and
hand­/
object­
to­
mouth).
A
Margin
of
Exposure
of
100
(
or
more)
is
considered
adequately
protective
for
this
assessment.

Dose
from
hand­
to­
mouth
activity
from
treated
turf:
Post­
application
dose
among
children
from
the
"
incidental"
ingestion
of
pesticide
residues
on
treated
turf
from
hand­
to­
mouth
transfer
(
i.
e.,
those
residues
that
end
up
in
the
mouth
from
a
child
touching
turf
and
then
putting
their
hands
in
their
mouth);

Dose
from
object­
to­
mouth
activity
from
treated
turf:
Post­
application
dose
among
children
from
incidental
ingestion
of
pesticide
residues
on
treated
turf
from
object­
to­
mouth
transfer
(
i.
e.,
those
residues
that
end
up
in
the
mouth
from
a
child
mouthing
a
handful
of
treated
turf);

Dose
from
soil
ingestion
activity:
Post­
application
dose
among
children
from
incidental
ingestion
of
soil
in
a
treated
area;

Dose
from
ingestion
of
trifluralin
granules
from
treated
turf:
Post­
application
dose
among
children
from
the
"
episodic"
ingestion
of
pesticide
granules
picked
up
from
treated
turf.
This
assessment
is
not
needed
for
trifluralin
since
an
endpoint
and
dose
for
acute
oral
risk
assessment
for
children
was
not
identified
by
the
HIARC
and
repeated
exposure
of
this
nature
is
not
expected.
41
The
term
"
episodic"
is
used
to
denote
an
event
(
granule
ingestion)
that
is
infrequent
to
very
infrequent.
The
term
"
incidental"
is
used
to
denote
the
more
likely
oral
ingestion
that
may
occur
following
typical
lawn
treatments.
Both
terms
are
used
to
distinguish
the
seasonal
and
inadvertent
oral
exposure
associated
with
lawn
use,
from
the
chronic
exposure
associated
with
treated
foods,
or
from
residue
in
drinking
water.
The
exposure
estimates
of
the
oral
ingestion
scenarios
(
except
granule
ingestion)
are
combined
to
establish
the
possible
(
if
not
likely)
upper­
end
of
oral
exposure
from
lawn
(
or
similar)
use.

Residue
on
Turf:
The
registrant
submitted
a
"
transferable"
residue
study
of
benefin
and
trifluralin
on
turf
(
Dissipation
of
Transferable
Residues
of
Benefin
and
Trifluralin
on
Turf
Treated
with
a
Formulation
of
the
Pesticides).
This
study
measured
surface
residue
available
to
be
dermally
or
orally
transferred,
post­
application.
The
study
was
conducted
from
June
to
September,
1997
at
three
geographical
locations
(
California,
Indiana,
and
Mississippi)
that
are
said
to
be
representative
of
the
climatic
and
turf
growing
conditions
expected
in
the
intended
use­
areas.
Turf
was
mowed
to
its
normal
cutting
height
prior
to
pesticide
application
and
no
irrigation,
mowing,
or
maintenance
chemical
applications
were
performed
for
the
duration
of
the
study.
A
granular
product
containing
1.33%
benefin
and
0.67%
trifluralin
was
applied
to
the
turf
in
a
single
application
at
the
maximum
label
rate
of
two
pounds
benefin
active
ingredient
per
acre
and
one
pound
trifluralin
active
ingredient
per
acre
using
a
drop
granule
spreader,
or
an
air­
powered
granular
applicator.
Samples
were
collected
at
days
0,
1,
2,
4,
and
7
following
application.
For
trifluralin,
the
study
limit
of
detection
(
LOD)
was
0.001

g/
cm2
and
the
limit
of
quantitation
(
LOQ)
was
0.003

g/
cm2.
Initial
transferable
residues
of
trifluralin
were
less
than
the
LOQ
and
ranged
from
notdetectable
to
0.002

g/
cm2.
The
average
transferable
residues
at
day
0
were
0.0011

g/
cm2,
just
slightly
higher
than
the
limit
of
detection.
After
day
0,
no
residues
were
detectable.

Exposure
Factors
/
Other
Estimates:
1)
the
turf
transferable
residue
(
TTR)
value
at
day
zero
(
0.0011

g/
cm2)
from
the
trifluralin­
specific
study
was
used
in
each
scenario;
2)
3
year
old
children
are
expected
to
weigh
an
average
15
kg;
3)
hand­
tomouth
exposures
are
based
on
a
frequency
of
20
events/
hour
and
a
surface
area
per
event
of
20
cm2
representing
the
palmar
surfaces
of
three
fingers;
4)
saliva
extraction
efficiency
is
50%
(
meaning
that
every
time
the
hand
goes
in
the
mouth
approximately
½
of
the
residues
on
the
hand
are
removed);
5)
object­
to­
mouth
exposures
are
based
on
a
25
cm2
surface
area;
6)
exposure
durations
are
expected
to
be
2
hours
based
on
information
in
the
Agency's
Exposure
Factors
Handbook;
and
7)
soil
residues
are
contained
in
the
top
centimeter.
42
Table
10
Oral
Ingestion
Exposure
Scenario
Route
of
Exposure
Application
Ratea
Exposure
mg/
kg/
day
MOEb
Hand
to
Mouth
Activity
on
Turfc
Oral
3.0
lb
ai/
acre
0.000088
>
100
Object
to
Mouth
Activity
on
Turfd
Oral
3.0
lb
ai/
acre
0.0000055
>
100
Incidental
Soil
Ingestione
Oral
3.0
lb
ai/
acre
1.5x10­
8
>
100
Footnotes:

a
Application
rates
represent
maximum
label
rates
from
current
EPA
registered
labels
(
Granular
rate
is
3.0
lb
ai/
acre).
b
MOEs
calculated
using
residues
which
would
be
found
on
day
of
treatment.
Short­
term
Oral
MOE
(
S­
T)
=
Short­
term
Incidental
Oral
NOAEL
(
10
mg/
kg/
day
/
short­
term
Oral
Dose
(
mg/
kg/
day)
with
a
target
MOE
of
100;
c
Hand­
to­
mouth
Dose
Calculation:
oral
dose
to
child
(
1­
6
year
old)
on
the
day
of
treatment
(
mg/
kg/
day)
=
TTR
at
day
0
normalized
to
application
rate
(
0.0033
ug/
cm2)
x
median
surface
area
for
1­
3
fingers
(
20
cm2/
event)
x
hand­
to­
mouth
rate
(
20
events/
hour)
x
exposure
time
(
2
hr/
day)
x
50%
saliva
extraction
factor
x
0.001
mg/
µ
g]
/
bw
(
15
kg
child).
d
Object
to
Mouth
Activity
on
­
Turf
Dose
Calculation:
oral
dose
to
child
(
1­
6
year
old)
on
the
day
of
treatment
=
TTR
at
day
0
normalized
to
application
rate
(
0.0033
ug/
cm2)
x
median
surface
area
for
1­
3
fingers
(
25
cm2/
event)
x
hand­
to­
mouth
rate
(
20
events/
hour)
x
0.001
mg/
µ
g]]
/
bw
(
15
kg
child).
e
Incidental
Soil
ingestion
­
Dose
Calculation:
oral
dose
to
child
(
1­
6
year
old)
on
the
day
of
treatment
(
mg/
kg/
day)
=
[
TTR
at
day
0
normalized
to
application
rate
(
0.0033
ug/
cm2)
x
fraction
of
residue
retained
on
uppermost
1
cm
of
soil
(
100%
or
1.0/
cm)
x
0.67
cm3/
g
soil
conversion
factor]
x
100
mg/
day
ingestion
rate
x
1.0E­
06
g/

g
conversion
factor]
/
bw
(
15
kg).

Table
11
Oral
Ingestion
/
Combined
Exposure
Exposure
Scenario
Oral
MOE
Combined
Oral
MOE
Child
Granules
(
3
lb
ai/
acre)
on
turf
Hand
to
Mouth
>
100
110,000
Object
to
Mouth
>
100
Incidental
Soil
Ingestion
>
100
4.5.4
Residential
Post­
Application
/
Carcinogenic
Risk
(
Q
1*
Approach)
43
Carcinogenic
risk
estimates
are
based,
in
part,
on
estimates
of
days
per
year,
persons
are
exposed
to
treated
areas
following
trifluralin
use.
Based
on
the
transferable
residue
study,
post­
application
exposure
to
residential
turfgrass
and
golf
course
turfgrass
will
occur
on
the
day
of
application
(
day
zero)
following
two
applications,
each
year.
It
is
further
estimated
that
the
duration
of
exposure
will
be
two
hours
(
while
exercising)
on
a
treated
lawn
and
four
hours
of
exposure
while
playing
golf.
As
with
residential
applicators,
the
assessment
is
based
on
50
years
of
trifluralin
use
and
exposure.

Exposure
estimates
are
also
based
on
data
that
measured
the
transfer
of
residue
(
any
chemical)
from
the
surface
of
treated
turf
to
persons
while
doing
specific
activities.
These
estimates
are
termed
"
transfer
coefficents"
and
are
7,300
for
residential
turf
(
while
exercising)
and
500
for
golfing
(
this
is
the
transfer
coefficient
in
the
draft
standard
operating
procedure
for
golfer
exposure
assessment
for
adults
and
children,
and
used
in
other
golfer
exposure
assessments).
As
in
the
post­
application
oral
assessment,
the
transferable
residue
estimate
(
0.0033
ug/
cm2)
is
taken
from
the
trifluralin­
specific
study
and
is
the
average
transferable
residues
at
day
0
(
after
day
0,
no
residues
were
detectable)
and
accounts
for
the
higher
rate
(
3lb
ai/
A)
used
on
turf
than
used
in
the
study
(
1lb
ai/
A).
These
estimates
form
the
basis
for
the
"
Lifetime
Average
Daily
Dermal
Dose",
or
LADD,
used
with
the
Q
1*
to
estimate
(
lifetime)
carcinogenic
risk
for
trifluralin
users.
44
Table
12.
Residential
Post­
Application
Carcinogenic
Risk
Exposure
Scenario
Application
Rate
(
lb
ai/
acre)
a
TTR/
DFR
(

g/
cm2)
b
Transfer
Coefficient
(
Tc)

(
cm2/
hr)
Exposure
Time
(
ET)

(
hrs/
day)
ADD
(
mg/
kg/
day
)
c
Days
of
Exposure
LADD
(
mg/
kg/
day)
d
Cancer
Riske
Dermal
contact
with
turf
3.0
0.0033
(
at
day
0)
7300
2
2.06
x
10­
5
2
8.08
x
10­
8
4.7
x
10­
10
Dermal
contact
with
golf
course
turfgrass
0.0033
(
at
day
0)
500
4
2.83
x
10­
6
2
1.11
x
10­
8
6.4
x
10­
11
a
Application
rate
for
turf
is
the
maximum
label
rate
for
turfgrass
use
patterns;
application
rate
for
vegetable
gardens
is
maximum
label
rate
for
use
on
vegetable
gardens.

b
Turf
transfer
residue
at
day
zero
(

g/
cm2)
=
[
AR
(
3
lbs
ai/
A)
*
TTR
residue
on
day
0
from
the
trifluralin­
specific
study;
Dislodgeable
foliar
residue
for
vegetable
gardens
at
day
zero
(

g/
cm2)
=
[
AR
(
4
lbs
ai/
A)
*
TTR
residue
on
day
0
from
the
trifluralin­
specific
study;

c
Average
daily
dermal
dose
(
ADD)
(
mg/
kg/
day)
=
[
DFR/
TTR
(

g/
cm2)
*
TC
(
cm2/
hr)
*
mg/
1,000

g
*
ET
(
hrs/
day)
*
Dermal
Absorption
(
3%)]
/

[
BW
(
70
kg)]

d
Lifetime
average
daily
dose
(
LADD)
=
Average
Daily
Dermal
Dose
(
mg/
kg/
day)
*
(
number
of
days
of
exposure
per
year
/
365
days/
year)
*
(
50
years
exposed
/
70
years
in
a
lifetime).

e
Cancer
Risk
=
LADD
(
mg/
kg/
day)
x
Q1*
(
mg/
kg/
day)
where
Q1*
=
0.00579.
45
4.5.5
Dermal
Sensitization
The
Agency
is
concerned
about
dermal
sensitization
reactions
in
adults
and
children
due
to
trifluralin
exposure
in
residential
settings.
At
present,
HED
has
no
method
for
determining
a
quantitative
endpoint
for
skin
sensitization
and,
therefore,
has
no
means
of
quantitatively
assessing
the
risk
resulting
from
trifluralin's
sensitization
potential.
HED
recommends
a
SENSITIZATION
warning
statement
on
all
labels
and
a
recommendation
that
contact
with
skin
should
be
avoided.
Note
that
the
Agency's
current
policy
is
that
it
is
not
feasible
to
require
personal
protective
equipment
for
homeowner
pesticide
users
due
to
concerns
about
noncompliance.

4.5.6
Trifluralin
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,
groundboom
use
can
also
be
a
source
of
exposure.
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.
The
Agency
is
now
requiring
interim
mitigation
measures
for
aerial
applications
that
must
be
placed
on
product
labeling.
The
Agency
has
completed
its
evaluation
of
the
new
data
base
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
AgDRIFT
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
and
risks
associated
with
aerial
as
well
as
other
application
types
where
appropriate.

5.0
AGGREGATE
EXPOSURE
/
RISK
ASSESSMENT
As
part
of
the
reregistration
eligibility
decision,
the
Agency
is
required
by
the
Food
Quality
Protection
Act
to
ensure
"
that
there
is
reasonable
certainty
that
no
harm
will
result
from
aggregate
exposure
to
pesticide
chemical
residue,
including
all
anticipated
dietary
exposures
and
other
exposures
for
which
there
is
reliable
information."

Trifluralin
has
been
assessed
for
the
following;
1)
acute
exposure
from
food
and
water
by
the
aPAD
approach;
2)
chronic
exposure
from
food
and
water
by
the
cPAD
approach;
3)
chronic
exposure
from
food
and
water
by
the
Q
1*
approach;
4)
short­
term
inhalation
exposure
to
homeowner
applicators
by
the
MOE
approach;
5)
50­
year
combined
inhalation
and
dermal
exposure
to
homeowner
applicators
by
the
Q
1*
approach;
6)
short­
term
oral
exposure
to
children
post­
application
on
turf
by
the
MOE
approach;
and
7)
50­
year
(
lifetime)
dermal
exposure
to
persons
(
golfers,
etc.)
post­
46
application
on
turf
by
the
Q
1*
approach.
(
Note
that
this
assessment
calculates
trifluralin
exposure
due
to
drinking
water
directly,
based
on
the
consumption
data
of
the
USDA
Continuing
Surveys
of
Food
Intakes
by
Individuals
(
CSFII),
1994­
1996
and
1998).

Aggregate
exposure
assessment
is
based,
in
part,
on
the
assumption
that
there
is
a
predictable
level
of
chronic
pesticide
exposure,
attributable
to
food
and
drinking
water,
and
this
level
is
estimated
on
a
per
day
basis
(
mg/
kg/
day)
by
using
averaged
estimates
of
residue,
use,
and
consumption.
This
average,
or
"
background"
level
of
exposure
is
assumed
to
be
constant,
not
seasonal,
and
residential
or
other
exposures
are
additive
to
this
background.
For
trifluralin,
homewner
use
is
highly
seasonal
(
mostly
early
Spring)
and
this
exposure
will
likely
be
acute
(
one
day
of
golf)
or
shortterm
(
multiple
residential
applications).
The
route
of
exposure
may
be
oral
(
children
on
turf),
dermal
(
at
application
or
post­
application),
or
by
inhalation
(
at
application).

The
chronic
dietary
exposure
and
risk
estimates
presented
in
section
4.4
(
above)
for
the
general
U.
S.
and
population
sub­
groups,
are
aggregate
estimates
based
on
both
food
and
drinking
water
sources.
Also,
the
oral
exposure
estimates
for
3
specific
activities
of
children
on
treated
turf
have
been
aggregated
to
form
an
upperbound
estimate
(
in
the
interest
of
safety).
Carcinogenic
risk
estimates
for
residential
applicators
have
been
aggregated
to
include
dermal
and
inhalation
exposure
and
to
represent
those
making
multiple
applications
to
lawns,
ornamentals,
and
gardens
with
a
single
type
of
application
device.
Also,
residential
applicator
exposure
has
been
aggregated
with
post­
application
exposure
on
turf
(
although
it
is
thought
this
combination
may
exceed
the
upper­
end
of
likely
exposure).

Aggregate
Short­
Term
Risk:
The
aggregate
(
3
specific
exposure
scenarios)
incidental
oral
exposure
estimate
for
children
on
turf
is
0.00009
mg/
kg/
day.
When
combined
with
the
estimated
chronic
dietary
exposure
(
0.000051
mg/
kg/
day)
for
children
1­
2
years
old,
the
sum
is
0.00014
mg/
kg/
day.
Compared
to
the
appropriate
dose
(
10
mg/
kg/
day)
for
short­
term
incidental
oral
risk
assessment,
this
aggregate
exposure
estimate
is
much
greater
than
the
target
MOE
of
100,
and
a
conclusion
of
safety
can
be
made.

Aggregate
Carcinogenic
Risk:
When
using
the
Q
1*
approach
to
assess
a
pesticide,
the
Agency
considers
all
exposure
to
be
additive
to
aggregate
carcinogenic
risk,
regardless
of
exposure
route
or
exposure
duration
(
per
season).
For
trifluralin,
this
means
that
the
chronic
exposure
from
foods
(
0.000022
mg/
kg/
day)
is
added
to
chronic
exposure
due
to
drinking
water
(
0.000008
mg/
kg/
day)
and
this
in
turn
is
added
to
exposure
estimated
for
residential
use.
Based
on
this
assumption,
carcinogenic
risk
estimates
are
made
for
those
applying
trifluralin
themselves,
each
season,
throughout
adulthood
(
50
years).

As
seen
in
Table
7,
the
exposure
and
carcinogenic
risk
estimates
for
residential
47
applicators
varies
significantly
depending
on
the
application
method,
even
if
other
inputs
(
rate
and
area
treated)
remain
the
same.
Since
carcinogenic
risk
assessment
attempts
to
reflect
long­
term
exposure,
the
most
appropriate
exposure
estimate
would
be
based
on
the
most
common
application
method;
the
push­
type
spreader.
The
Lifetime
Average
Daily
Dose
estimated
for
this
application
method
is
negligible
(
0.0000006
mg/
kg/
day),
and
when
added
to
the
chronic
dietary
(
food
and
water)
exposure
the
aggregate
carcinogenic
risk
estimate
is
2x10­
7.

6.0
CUMULATIVE
EXPOSURE
ASSESSMENT
Section
408(
b)(
2)(
D)(
v)
of
the
FFDCA
requires
that,
when
considering
whether
to
establish,
modify,
or
revoke
a
tolerance,
the
Agency
consider
"
available
information"
concerning
the
cumulative
effects
of
a
particular
pesticide's
residues
and
"
other
substances
that
have
a
common
mechanism
of
toxicity."

EPA
does
not
have,
at
this
time,
available
data
to
determine
whether
trifluralin
has
a
common
mechanism
of
toxicity
with
other
substances.
Unlike
other
pesticides
for
which
EPA
has
followed
a
cumulative
risk
approach
based
on
a
common
mechanism
of
toxicity,
EPA
has
not
made
a
common
mechanism
of
toxicity
finding
as
to
trifluralin
and
any
other
substances.
For
the
purposes
of
this
tolerance
action,
therefore,
EPA
has
not
assumed
that
trifluralin
has
a
common
mechanism
of
toxicity
with
other
substances.
For
information
regarding
EPA's
efforts
to
determine
which
chemicals
have
a
common
mechanism
of
toxicity
and
to
evaluate
the
cumulative
effects
of
such
chemicals,
see
the
policy
statements
released
by
EPA's
Office
of
Pesticide
Programs
concerning
common
mechanism
determinations
and
procedures
for
cumulating
effects
from
substances
found
to
have
a
common
mechanism
on
EPA's
website
at
http://
www.
epa.
gov/
pesticides/
cumulative/.

7.0
HUMAN
INCIDENT
DATA
REVIEW
Based
on
California
data
and
the
Incident
Data
System,
it
appears
that
the
majority
of
cases
involved
skin
and
eye
illnesses.
Poison
Control
Center
data
would
tend
to
support
these
results,
dermal
and
ocular
effects
were
some
of
the
most
common
effects
reported.
Appropriate
protective
clothing
to
protect
the
skin
and
eyes
of
applicators
is
recommended.
The
following
data
bases
have
been
consulted
for
the
poisoning
incident
data
on
the
active
ingredient
trifluralin.

OPP
Incident
Data
System
(
IDS):
Reports
of
incidents
from
various
sources,
including
registrants,
other
federal
and
state
health
and
environmental
agencies
and
individual
consumers,
submitted
to
OPP
since
1992.
Reports
submitted
to
the
Incident
Data
System
represent
anecdotal
reports
or
allegations
only,
unless
otherwise
stated.
Typically
no
conclusions
can
be
drawn
implicating
the
pesticide
as
a
cause
of
any
of
the
reported
health
effects.
Nevertheless,
sometimes
with
enough
cases
and/
or
48
enough
documentation
risk
mitigation
measures
may
be
suggested.
Of
the
30
incidents
listed
in
the
IDS,
nine
involved
hives,
swelling,
itching,
shortness
of
breath,
or
asthma
suggesting
that
trifluralin
may
cause
an
allergic
reaction
or
asthmatic
reaction
in
susceptible
individuals.
The
other
most
common
complaints
were
dermal
effects
such
as
rash.

Poison
Control
Centers:
As
the
result
of
a
data
purchase
by
EPA,
OPP
received
Poison
Control
Center
data
covering
the
years
1993
through
1998
for
all
pesticides.
Most
of
the
national
Poison
Control
Centers
(
PCCs)
participate
in
a
national
data
collection
system,
the
Toxic
Exposure
Surveillance
System
which
obtains
data
from
about
65­
70
centers
at
hospitals
and
universities.
PCCs
provide
telephone
consultation
for
individuals
and
health
care
providers
on
suspected
poisonings,
involving
drugs,
household
products,
pesticides,
etc.

Subgroup
Exposures
Outcome
determined
Seen
in
Health
Care
Facility
Occupational:
adults
and
older
children
46
33
26
Non­
occupational:
adults
and
older
children
90
56
27
Children
under
age
six
64
35
4
In
general,
trifluralin
is
less
likely
to
cause
minor,
moderate,
or
life­
threatening
symptoms
than
other
pesticides
except
among
non­
occupational
cases
where
moderate
effects
are
more
likely.
There
were
no
major
or
life­
threatening
cases
or
cases
requiring
hospitalization
or
intensive
care
except
for
one
case
involving
a
child
that
was
hospitalized.
The
one
case
that
was
hospitalized
involved
an
ingestion
in
a
2
year
old
that
did
not
develop
any
symptoms.
It
appears
likely
this
case
was
kept
in
the
hospital
overnight
for
observation.
Symptoms
most
commonly
reported
in
ten
or
more
individuals
were
eye
irritation/
pain
(
25
reports),
nausea
(
16
reports),
vomiting
(
13
reports),
and
skin
irritation/
pain
(
10
reports).
Of
the
symptomatic
cases,
one­
quarter
involved
exposure
to
residue
rather
than
direct
spray
or
spill.

California
Department
of
Pesticide
Regulation:
California
has
collected
uniform
data
on
suspected
pesticide
poisonings
since
1982.
Physicians
are
required,
by
statute,
to
report
to
their
local
health
officer
all
occurrences
of
illness
suspected
of
being
related
to
exposure
to
pesticides.
The
majority
of
the
incidents
involve
workers.
Information
on
exposure
(
worker
activity),
type
of
illness
(
systemic,
eye,
skin,
eye/
skin
and
respiratory),
likelihood
of
a
causal
relationship,
and
number
of
days
off
work
and
in
the
hospital
are
provided.
49
The
California
data
indicates
that
handlers
(
applicators
and
mixer/
loaders)
were
associated
with
more
exposures
than
any
other
category.
These
illnesses
included
symptoms
of
conjunctivitis,
swollen
arms,
hand,
and
face
and
a
rash,
eye
irritation,
tearing
and
red
eyes,
headache,
skin
irritation,
and
abdominal
pain.
Effects
to
the
skin,
such
as
burning,
itching,
rash,
appeared
to
be
the
most
prevalent
problems
from
exposure
to
trifluralin.

National
Pesticide
Information
Center:
On
the
list
of
the
top
200
chemicals
for
which
NPIC
received
calls
from
1984­
1991
inclusively,
triflularin
was
ranked
53rd
with
75
incidents
in
humans
reported
and
17
in
animals
(
mostly
pets).
50
Appendix
A:
Pesticide
Handler
Exposure
Database
(
PHED)
Version
1.1
(
8/
98)

PHED
was
designed
by
a
task
force
of
representatives
from
the
U.
S.
EPA,
Health
Canada,
the
California
Department
of
Pesticide
regulation,
and
member
companies
of
the
American
Crop
Protection
Association.
PHED
is
a
software
system
consisting
of
two
parts
­­
a
database
of
measured
exposure
values
for
workers
involved
in
the
handling
of
pesticides
under
actual
field
conditions
and
a
set
of
computer
algorithms
used
to
subset
and
statistically
summarize
the
selected
data.
Currently,
the
database
contains
values
for
over
1,700
monitored
individuals
(
i.
e.,
replicates)

Users
select
criteria
to
subset
the
PHED
database
to
reflect
the
exposure
scenario
being
evaluated.
The
subsetting
algorithms
in
PHED
are
based
on
the
central
assumption
that
the
magnitude
of
handler
exposures
to
pesticides
are
primarily
a
function
of
activity
(
e.
g.,
mixing/
loading,
applying),
formulation
type
(
e.
g.,
wettable
powders,
granulars),
application
method
(
e.
g.,
aerial,
groundboom),
and
clothing
scenarios
(
e.
g.,
gloves,
double
layer
clothing).

Once
the
data
for
a
given
exposure
scenario
have
been
selected,
the
data
are
normalized
(
i.
e.,
divided
by)
by
the
amount
of
pesticide
handled
resulting
in
standard
unit
exposures
(
milligrams
of
exposure
per
pound
of
active
ingredient
handled).
Following
normalization,
the
data
are
statistically
summarized.
The
distribution
of
exposure
values
for
each
body
part
(
e.
g.,
chest
upper
arm)
is
categorized
as
normal,
lognormal,
or
"
other"
(
i.
e.,
neither
normal
nor
lognormal).
A
central
tendency
value
is
then
selected
from
the
distribution
of
the
exposure
values
for
each
body
part.
These
values
are
the
arithmetic
mean
for
normal
distributions,
the
geometric
mean
for
lognormal
distributions,
and
the
median
for
all
"
other"
distributions.
Once
selected,
the
central
tendency
values
for
each
body
part
are
composited
into
a
"
best
fit"
exposure
value
representing
the
entire
body.

The
unit
exposure
values
calculated
by
PHED
generally
range
from
the
geometric
mean
to
the
median
of
the
selected
data
set.
To
add
consistency
and
quality
control
to
the
values
produced
from
this
system,
the
PHED
Task
Force
has
evaluated
all
data
within
the
system
and
has
developed
a
set
of
grading
criteria
to
characterize
51
the
quality
of
the
original
study
data.
The
assessment
of
data
quality
is
based
on
the
number
of
observations
and
the
available
quality
control
data.
These
evaluation
criteria
and
the
caveats
specific
to
each
exposure
scenario
are
summarized
in
Appendix
A,
Table
A1.
While
data
from
PHED
provide
the
best
available
information
on
handler
exposures,
it
should
be
noted
that
some
aspects
of
the
included
studies
(
e.
g.,
duration,
acres
treated,
pounds
of
active
ingredient
handled)
may
not
accurately
represent
labeled
uses
in
all
cases.
HED
has
developed
a
series
of
tables
of
standard
unit
exposure
values
for
many
occupational
scenarios
that
can
be
utilized
to
ensure
consistency
in
exposure
assessments.
Unit
exposures
are
used
which
represent
different
levels
of
personal
protection
as
described
above.
Protection
factors
were
used
to
calculate
unit
exposure
values
for
varying
levels
of
personal
protection
if
data
were
not
available.

Appendix
B:
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
Handler
Studies
A
report
was
submitted
by
the
ORETF
(
EPA
MRID
44972201)
that
presented
data
in
which
the
application
of
various
products
used
on
turf
by
homeowners
and
lawncare
operators
(
LCOs)
was
monitored.
All
of
the
data
submitted
in
this
report
were
completed
in
a
series
of
studies.
The
study
that
monitored
homeowner
exposure
scenarios
using
a
push­
type
spreader
is
summarized
below.

Homeowner
Push­
Type
Spreader
(
OMA003):
A
mixer/
loader/
applicator
study
was
performed
by
the
Outdoor
Residential
Exposure
Task
Force
(
ORETF)
using
Dacthal
(
active
ingredient
DCPA,
dimethyl
tetrachloroterephthalate)
as
a
surrogate
compound
to
determine
"
generic"
exposures
of
individuals
applying
a
granular
pesticide
formulation
to
residential
lawns.
A
total
of
30
volunteers
were
monitored
using
passive
dosimetry
(
inner
and
outer
whole
body
dosimeters,
hand
washes,
face/
neck
wipes,
and
personal
inhalation
monitors).
Each
volunteer
carried,
loaded,
and
applied
two
25­
lb
bags
of
fertilizer
(
0.89%
active
ingredient)
with
a
rotary
type
spreader
to
a
lawn
covering
10,000
ft2.
The
target
application
rate
was
2
lb
ai/
acre
(
actual
rate
achieved
was
about
1.9
lbs
ai/
acre).
The
average
application
time
was
22
minutes,
including
loading
the
rotary
push
spreader
and
disposing
of
the
empty
bags.
Each
replicate
handled
approximately
0.45
lbs
ai.
Dermal
exposure
was
measured
using
inner
and
outer
whole
body
dosimeters,
hand
washes,
face/
neck
washes,
and
personal
air
monitoring
devices
with
OVS
tubes.
The
study
results
are
normalized
to
kg
ai
handled.
The
US
EPA
HED
typically
assumes
that
residential
applicators
wear
short
pants
and
short­
sleeved
shirts,
as
described
in
the
Residential
SOPs
(
1997).
Therefore,
the
table
reports
the
dermal
exposures
for
the
short
pants
and
short­
sleeve
shirt
clothing
scenario
only.

Homeowner
Hose­
end
and
Hand­
held
Sprayer:
(
EPA
MRID
44518501)
Applications
of
Sevin
Liquid
®
Carbaryl
insecticide
[
RP­
2
liquid
(
21%)]
were
made
by
52
volunteers
to
two
young
citrus
trees
and
two
shrubs
in
each
replicate
that
was
monitored
in
the
study.
The
test
field
was
located
only
in
Florida.
Twenty
(
20)
replicates
were
monitored
using
hose­
end
sprayer
(
Ortho
®
DIAL
or
Spray
®
hose
end
sprayer),
and
20
replicates
were
monitored
using
hand
held
pump
sprayers
(
low
pressure
handwands).

Each
replicate
opened
the
end­
use
product,
added
it
to
the
hose­
end
sprayer
or
hand
held
pump
and
then
applied
it
to
the
trees
and
shrubs.
After
application
to
two
trees
and
two
shrubs
dosimeters
were
collected.
Inhalation
exposure
was
monitored
with
personal
air
sampling
pumps
with
OVS
tubes
attached
to
the
shirt
collar
in
the
breathing
zone.
Dermal
exposure
was
assessed
by
extraction
of
carbaryl
from
inner
and
outer
100
percent
cotton
dosimeters.
The
inner
and
outer
dosimeters
were
segmented
into:
lower
and
upper
arms,
lower
and
upper
legs,
front
and
back
torso.
No
gloves
were
worn
therefore
hand
exposure
was
assessed
with
400
ml
handwash
with
0.01
percent
Aerosol
OT­
75
sodium
dioctyl
sulfosuccinate
(
OTS).
One
hundred
percent
cotton
handkerchiefs
wetted
with
25
ml
OTS
were
used
to
wipe
face
and
neck
to
determine
exposure.

Field
fortification
recoveries
for
passive
dosimeters
averaged
88.3
percent
for
inner
and
76.2
percent
for
outer
dosimeters.
Face
and
neck
wipe
fortifications
average
82.5
percent.
Handwash
and
inhalation
OVS
tube
field
fortification
averaged
>
90
percent.
Inner
and
outer
dosimeter
and
face
and
neck
wipe
residues
were
adjusted
for
field
fortification
results.
Handwash
and
inhalation
residues
were
not
adjusted.

Laboratory
method
validation
for
each
matrix
fell
within
the
acceptable
range
of
70
to
120
percent.
The
limit
of
quantitation
(
LOQ)
was
1.0

g/
sample
for
all
media
except
the
inhalation
monitors
where
the
LOQ
was
0.01

g/
sample.
The
limit
of
detection
(
LOD)
was
0.5

g/
sample
for
all
media
except
the
inhalation
monitors
where
the
LOQ
was
0.005

g/
sample.

For
use
in
reregistration
documents,
the
dermal
exposure
was
calculated
by
adding
the
values
from
the
hand
rinses,
face/
neck
wipes
to
the
outer
dosimeter
lower
legs
and
lower
arms
plus
the
inner
dosimeter
front
and
rear
torso,
upper
legs
and
upper
arms.
This
accounts
for
the
residential
handler
wearing
short­
sleeved
shirt
and
short
pants.
The
results
for
the
low
pressure
handwand
are
summarized
in
Table
3
below.

The
distribution
of
the
unit
exposure
values
is
categorized
as
normal,
lognormal,
or
"
other"
(
i.
e.,
neither
normal
nor
lognormal).
A
central
tendency
value
is
selected
from
the
distribution
of
the
exposure
values.
These
values
are
the
arithmetic
mean
for
normal
distributions,
the
geometric
mean
for
lognormal
distributions,
and
the
median
for
all
"
other"
distributions.
The
dermal
exposure
had
a
lognormal
distribution
so
the
geometric
mean
value
was
used
to
determine
dermal
exposure
to
trifluralin.
The
inhalation
exposure
had
neither
a
normal
or
lognormal
distribution
so
the
median
was
53
used
to
determine
inhalation
exposure
to
trifluralin.
54
APPENDIX
C:
Proprietary
Studies
Worker
Exposure
Study
Durin/
g
Application
of
Regent
20GR
In
Banana
Plantation
(
Fipronil):
Handler
exposure
data
from
a
proprietary
granular
mixer/
loader/
applicator
study
(
MRID
45250702)
in
bananas
using
fipronil
(
Regent
20GR)
were
used
in
place
of
PHED
data
for
the
"
loading/
applying
granulars
using
a
spoon,
measuring
scoop,
shaker
can
or
by
hand"
scenario.
This
fipronil
study
is
considered
to
be
an
appropriate
source
of
surrogate
handler
exposure
data
for
trifluralin
because
formulation
types
are
similar
(
granular)
and
application
methods
are
similar
(
applying
granulars
with
a
spoon).
The
study
is
considered
to
be
of
sufficient
quality
for
use
in
risk
assessment.
Data
compensation
for
these
data
should
be
determined.

Several
factors
should
be
considered
when
using
fipronil
data
in
the
trifluralin
exposure
assessment.
Protection
factors
used
to
calculate
trifluralin
dermal
unit
exposure
values,
based
on
the
fipronil
unit
exposure
values,
include
a
standard
50%
protection
factor
for
the
torso,
a
10%
protection
factor
for
legs,
based
on
shorts,
and
a
10%
protection
factor
for
arms,
based
on
a
short­
sleeved
shirt.
These
protection
factors
represent
the
typical
attire
assumed
to
be
worn
by
a
homeowner
during
pesticide
application
(
shorts
and
short­
sleeved
shirt).
The
10%
protection
factor
for
shorts
and
the
10%
protection
factor
for
a
short­
sleeved
shirt
are
not
standard
protection
factors
used
by
the
Agency;
rather,
these
values
are
based
on
the
best
professional
judgement
of
Agency
scientists
and
are
appropriate
for
calculating
rangefinding
estimates
only.
55
