Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
EPA
Registration
Division
Contact:
Mr.
J.
A.
Tompkins,
703­
305­
5697
1.
E.
I.
du
Pont
de
Nemours
and
Company
PP
No.
(
to
be
assigned)

EPA
has
received
a
pesticide
petition
(
PP
No.
to
be
assigned)
from
E.
I.
du
Pont
de
Nemours
and
Company,
DuPont
Crop
Protection,
Laurel
Run
Plaza,
P.
O.
Box
80038,
Wilmington,
DE
19880­
0038,
proposing
pursuant
to
section
408
(
d)
of
the
Federal
Food,
Drug,
and
Cosmetic
Act,
21
U.
S.
C.
346a
(
d),
to
amend
40
CFR
Part
180.439
by
establishing
a
tolerance
for
residues
of
the
herbicide
thifensulfuron
methyl
{
Methyl­
3­[[[[(
4­
methoxy­
6­
methyl­
1,3,5­
triazin­
2­
yl)
amino]
carbonyl]
amino]
sulfonyl]
­
2­
thiophenecarboxylate}
in
or
on
the
following
raw
agricultural
commodities:
Rice
grain
at
0.05
ppm,
Rice
straw
at
0.05
ppm,
Grain
sorghum
grain
at
0.05
ppm,
Grain
sorghum
forage
at
0.05
ppm,
and
Grain
sorghum
stover
at
0.05
ppm.
EPA
has
determined
that
the
petition
contains
data
or
information
regarding
the
elements
set
forth
in
section
408
(
d)
(
2)
of
the
FFDCA;
however,
EPA
has
not
fully
evaluated
the
sufficiency
of
the
submitted
data
at
this
time
or
whether
the
data
supports
granting
of
the
petition.
Additional
data
may
be
needed
before
EPA
rules
on
the
petition.

A.
Residue
Chemistry
1a.
Plant
Metabolism
The
qualitative
nature
of
the
residues
of
thifensulfuron
methyl
in
plants
is
adequately
understood.
Three
plant
metabolism
studies
 
in
wheat,
corn,
and
soybeans
­
were
conducted.
Crops
were
treated
with
[
thiophene­
2­
14C]
and
[
triazine­
2­
14C]
thifensulfuron
methyl
via
direct
foliage
application.
[
14C]
Thifensulfuron
methyl
was
rapidly
metabolized
in
all
three
crops,
and
the
nature
of
the
metabolites
was
essentially
the
same
regardless
of
the
crop.
In
all
three
crops,
metabolism
involved
cleavage
of
the
urea
bridge,
metabolism
(
O­
demethylation)
of
the
methoxy
group
on
the
triazine
ring,
and
hydrolysis
of
the
methyl
ester
group
on
the
thiophene
ring.
Minor
differences
in
the
formation
and
decline
of
short­
lived
intermediates
were
observed,
however
these
differences
were
not
environmentally
significant
because
of
the
low
levels
of
these
intermediate
metabolites
in
the
crops.

Metabolism
studies
conducted
with
14C­
thifensulfuron
methyl
on
wheat
(
at
a
rate
of
approximately
28­
30
g
ai/
acre)
under
field
conditions
showed
no
significant
residues
of
thifensulfuron
methyl
or
its
degradation
products
(
i.
e.,
all
less
than
0.01
ppm)
in
wheat
grain
at
maturity.
Mature
straw
total
residues
were
0.45
to
0.80
ppm
for
the
triazine
and
thiophenelabeled
tests,
respectively.
Metabolites
in
wheat
straw
included
thifensulfuron
methyl,
thifensulfuron
acid,
O­
demethyl
thifensulfuron
methyl,
2­
ester­
3­
sulfonamide,
2­
acid­
3­
sulfonamide,
triazine
urea,
triazine
amine,
and
O­
demethyl
triazine
amine.
Complete
breakdown
of
[
14C]
thifensulfuron
methyl
and/
or
metabolites
resulting
in
re­
incorporation
of
the
radiolabel
into
natural
plant
constituents
(
e.
g.,
sugars)
was
also
observed.
No
single
metabolite
was
greater
than
0.06
ppm
in
the
mature
wheat
straw.
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
Metabolism
studies
with
[
14C]
thifensulfuron
methyl
were
conducted
(
at
a
rate
of
approximately
14
g
ai/
acre)
in
field
grown
corn.
There
were
no
detectable
residues
of
thifensulfuron
methyl
or
its
transformation
products
in
corn
grain
(
i.
e.,
all
less
than
0.01
ppm)
or
foliage
(
i.
e.,
all
less
than
0.02
ppm)
at
maturity.
Analysis
of
non­
mature
foliar
samples
showed
rapid
and
extensive
metabolism
of
thifensulfuron
methyl.
Among
the
residues
detected
were
thifensulfuron
methyl,
2­
acid­
3­
sulfonamide,
triazine
urea,
triazine
amine,
O­
demethyl
triazine
urea,
and
O­
demethyl
triazine
amine.
Thifensulfuron
acid
and
2­
ester­
3­
sulfonamide,
which
are
metabolites
seen
in
other
plant
metabolism
studies
(
wheat
and
soybean),
were
not
detected,
but
were
most
likely
transient
intermediates
(
both
plausible
precursors
to
2­
acid­
3­
sulfonamide)
in
the
corn
plants.

Metabolism
studies
were
conducted
with
soybeans
under
greenhouse
conditions
(
at
rates
of
3
and
6
g
ai
per
acre).
There
were
no
detectable
residues
(
i.
e.,
all
less
than
0.01
ppm)
in
the
beans
or
pods
at
either
rate
at
final
harvest.
Analysis
of
non­
mature
foliar
samples
showed
extensive
metabolism
of
thifensulfuron
methyl.
Residues
detected
included
thifensulfuron
methyl,
thifensulfuron
acid,
2­
ester­
3­
sulfonamide,
2­
acid­
3­
sulfonamide,
triazine
amine,
and
O­
demethyl
triazine
amine.

1b.
Confined
Rotational
Crop
Studies
Two
different
crop
rotation
scenarios
were
investigated,
one
involving
a
bare
ground
application,
the
other
with
a
cover
crop
(
wheat).
No
significant
difference
in
metabolic
profile
was
observed
in
the
rotated
crops
(
beets,
peas,
and
sunflowers)
under
either
scenario.
No
thifensulfuron
methyl
(
i.
e.,
<
0.01
mg/
kg)
was
detected
in
any
food
or
feed
item
from
any
of
the
rotated
crops.

A
confined
greenhouse
crop
rotation
study
(
following
application
to
bare
soil)
was
conducted
with
thiophene­
14C
thifensulfuron
methyl
by
planting
beets,
peas,
and
sunflowers
at
either
a
30
or
120
day
treatment­
to­
planting
interval.
The
application
rate
used
was
35
­
38
g
ai/
acre.
Total
soil
residue
levels
at
planting
were
low,
0.01
 
0.02
mg/
kg
for
both
the
30­
and
120­
day
aging
periods.
Levels
of
thifensulfuron
methyl
at
planting
accounted
for
<
0.01
mg/
kg
at
the
end
of
each
aging
period.
There
were
no
significant
residues
(
i.
e.,
all
less
than
0.005
ppm)
in
food
items
(
beet
root,
peas,
sunflower
seeds)
in
crops
planted
30
or
120
days
following
soil
treatment.
There
were
minor
detectable
residues
(
0.02
to
0.05ppm)
in
animal
feed
items
(
beet
foliage
and
sunflower
foliage).
Thifensulfuron
methyl
was
only
identified
(<
0.01
ppm)
in
sunflower
foliage
73
days
after
treating
the
soil;
other
minor
components
observed
were
polar.

A
confined
greenhouse
crop
rotation
study
(
following
triazine­
14C
thifensulfuron
methyl
treated
wheat)
was
conducted
using
beet
root,
peas,
pea
pods,
and
sunflower
as
following
crops.
The
study
used
an
application
rate
of
15
g
ai/
acre,
and
a
45
or
75
day
treatment­
to­
planting
interval.
At
the
end
of
the
45­
and
75­
day
aging
periods
(
after
incorporation
of
the
cover
crop),
soil
residue
levels
were
0.01
 
0.02
mg
thifensulfuron
methyl
equivalents
per
kg
of
soil.
Thifensulfuron
methyl
was
not
detected
in
the
soil
after
45
days;
triazine
urea
was
the
principal
soil
component
at
the
45­
and
75­
day
planting
interval.
There
were
no
substantial
residues
(
i.
e.,
all
less
than
0.01
ppm)
in
food
items
(
beet
root,
peas,
pea
pods,
sunflower
(
seeds
and
heads)
in
crops
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
planted
45
or
75
days
following
treated
wheat
incorporation
into
the
soil.
There
were
minor
detectable
residues
in
animal
feed
items.
Sunflower
and
pea
foliage
contained
0.04
 
0.05
ppm
and
0.01
­
0.02
ppm
for
the
45
and
75
day
planting,
respectively.
Small
amounts
of
triazine
amine
(<
0.03
ppm),
triazine
urea,
and
O­
demethyl
triazine
amine
were
identified
in
these
fractions.

The
proposed
use
of
thifensulfuron
methyl
on
grain
sorghum
and
rice
is
supported
by
the
wheat
and
field
corn
metabolism
studies.

2.
Analytical
Methods
For
wheat,
barley,
and
soybeans,
the
analytical
methods
use
liquid
chromatography
and
a
photoconductivity
detector
for
thifensulfuron
methyl.
Coupled
with
extraction,
cleanup
and
isolation
procedures,
these
methods
provide
a
means
of
determining
thifensulfuron
methyl
in
soybeans,
and
in
wheat
and
barley
straw,
with
a
detection
limit
of
50
ppb
(
50
ng/
g),
based
on
a
5­
gram
sample
(
soybeans)
or
a
10­
gram
sample
(
wheat
and
barley).

For
corn
forage
and
whole
ears,
the
analytical
method
used
liquid
chromatography
and
a
photoconductivity
detector
for
thifensulfuron
methyl.
Coupled
with
extraction,
cleanup
and
isolation
procedures,
this
method
provides
a
means
of
determining
thifensulfuron
methyl
in
kernels
with
a
detection
limit
of
20
ppb
(
20
ng/
g),
based
on
a
25­
gram
sample,
and
50
ppm
(
50
ng/
g)
based
on
a
10
gram
sample
for
green
forage
and
whole
ears.
For
determination
of
thifensulfuron
methyl
residues
in
corn
processed
fractions
(
processed
corn
oil
and
processed
corn
meal),
the
method
uses
HPLC
with
UV
detection
at
254
nm.
This
method
provides
a
means
to
determine
thifensulfuron
methyl
at
levels
as
low
as
0.02
ppm,
based
on
a
10
gram
sample.

Thifensulfuron
methyl
residues
in
canola
and
flax
samples
were
determined
by
an
analytical
method
based
on
the
use
of
liquid
chromatography
with
eluent
and
column
switching
with
photometric
detection
at
254
nm
at
levels
as
low
as
0.02
ppm
(
limit
of
quantitation)
using
a
5
gram
sample.

Residues
in
cotton
seed
and
gin
trash
were
determined
based
on
the
use
of
column­
switching
liquid
chromatography
with
detection
via
positive
ion
electrospray
mass
spectroscopy.
The
limit
of
quantitation
was
determined
to
be
20
ng/
g
and
the
limit
of
detection
was
estimated
to
be
6
ng/
g,
based
on
a
5
gram
sample.

Residues
in
rice
commodities,
and
in
grain
sorghum
forage
and
stover,
were
determined
with
an
analytical
method
utilizing
sample
extraction
by
homogenization
in
a
potassium
phosphate
buffer
solution.
The
extracts
were
cleaned­
up
and
concentrated
by
solid­
phase
extraction.
Analysis
was
performed
by
reversed­
phase
HPLC
and
quantitatively
analyzed
by
tandem
mass
spectrometric
detection.
The
target
limit
of
quantitation
(
LOQ)
was
0.05
ppm
for
these
commodities.

Thifensulfuron
methyl
residues
in
grain
sorghum
grain
were
determined
by
an
analytical
method
utilizing
LC/
MS/
MS
analysis.
The
analytes
were
resolved
by
HPLC
chromatography
and
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
quantitatively
analyzed
by
tandem
mass
spectrometric
detection.
The
LOQ
was
0.05
ppm
for
grain
sorghum
grain.

3.
Magnitude
of
Residue
a.
Wheat
and
Barley
Grain
and
Straw
Field
tests
were
conducted
on
wheat
and
barley.
Residues
of
thifensulfuron
methyl
were
determined
in
wheat
and
barley
(
grain
and
straw)
after
single
postemergence
applications
of
thifensulfuron
methyl
at
rates
of
0
­
4
oz
ai/
acre
in
wheat
and
0
­
2
oz
ai/
acre
in
barley.
The
PHI
was
41­
140
days
for
the
wheat
grain
and
straw
samples,
49­
116
days
for
barley
grain,
and
60­
89
days
for
barley
straw.
No
quantifiable
residues
(
i.
e.,
all
less
than
0.02
ppm
for
grain
or
0.05
ppm
for
straw)
were
found
in
any
samples
at
normal
harvest.

In
separate
studies,
wheat
was
treated
with
thifensulfuron
methyl
at
a
rate
of
0.5
oz.
ai/
acre
or
higher,
and
harvested
at
PHIs
ranging
from
25­
42
days.
No
thifensulfuron
methyl
residues
were
detected
in
wheat
grain
or
straw
(
i.
e.,
all
less
than
0.02
ppm
or
0.05
ppm,
respectively)
in
any
of
the
trials
at
normal
harvest.
Barley
was
treated
with
thifensulfuron
methyl
at
a
rate
of
0.5
oz.
ai/
acre.
Samples
of
mature
barley
grain
and
straw
were
taken
from
the
test
plots
at
a
PHI
of
approximately
40
days
after
the
test
substance
was
applied.
All
results
were
below
0.05
ppm
for
grain
and
0.1
ppm
for
straw.

The
current
tolerance
for
thifensulfuron
methyl
on
wheat
and
barley
grain
is
0.05
ppm,
and
on
wheat
and
barley
straw
the
tolerance
is
0.1
ppm.

b.
Corn
Grain,
Forage
and
Fodder
Field
tests
were
conducted
at
sites
representative
of
the
major
U.
S.
corn
growing
regions.
Tests
included
two
decline
studies.
Residues
of
thifensulfuron
methyl
were
determined
in
corn
grain,
forage,
and
fodder
after
a
single
postemergent
application
of
thifensulfuron
methyl
at
rates
from
0
to
1
oz
ai/
acre.
PHIs
were
80­
154
days
for
the
grain
sample,
0­
97
days
for
forage,
and
82­
154
days
for
fodder.
No
residues
above
the
quantitation
limit
(
0.02
mg/
kg
for
grain,
0.05
mg/
kg
for
forage/
fodder)
were
found
in
any
grain
or
fodder
samples
at
normal
harvest.
Residues
in
forage
declined
very
rapidly
with
time.
Even
with
treatment
at
several
times
the
typical
use
rate,
residues
were
below
the
limit
of
quantitation
within
14
days
after
treatment.
In
another
study,
plots
were
treated
with
thifensulfuron
methyl
at
rates
of
0.5,
1.0,
and
2.0
oz.
ai/
acre.
No
thifensulfuron
methyl
was
detected
(
quantitation
limit
of
0.02
ppm)
in
grain
from
the
2.0
oz.
application
rate.
No
residues
of
thifensulfuron
methyl
were
detected
in
the
processed
fractions
(
corn
oil
and
corn
meal).

Field
tests
were
also
conducted
to
determine
residues
of
thifensulfuron
methyl
in
field
corn
commodities
after
a
pre­
plant
or
at­
planting,
exaggerated
rate
application.
The
analytical
method
limit
of
quantitation
(
LOQ)
was
0.05
ppm
and
the
limit
of
detection
(
LOD)
was
0.02
ppm.
In
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
these
exaggerated
rate
studies,
no
residues
were
detected
at
or
above
0.02
ppm
in
corn
forage,
grain,
or
stover.

The
current
tolerance
for
thifensulfuron
methyl
on
field
corn
grain
is
0.05
ppm,
and
on
field
corn
forage
and
stover
the
tolerance
is
0.1
ppm.
These
tolerances
are
adequate
to
support
both
the
current
and
proposed
uses
of
thifensulfuron
methyl
on
field
corn.

c.
Soybeans
A
study
was
conducted
to
evaluate
the
magnitude
of
residues
of
thifensulfuron
methyl
in
soybeans
at
either
0.125
oz.
ai/
acre
or
0.25
oz.
ai/
acre.
All
applications
were
made
approximately
60
days
before
harvest
and
were
postemergence
foliar
broadcast
treatments.
All
thifensulfuron
methyl
residues
in
treated
soybeans
were
below
the
limit
of
quantitation
of
0.05
ppm
at
normal
harvest.

Field
tests
were
also
conducted
to
determine
residues
of
thifensulfuron
methyl
in
soybean
seed
after
a
pre­
plant
or
at­
planting,
exaggerated
rate
application.
The
analytical
method
LOQ
was
0.05
ppm
and
the
LOD
was
0.02
ppm.
In
these
exaggerated
rate
studies,
no
residues
were
detected
at
or
above
0.02
ppm.

The
current
tolerance
for
thifensulfuron
methyl
on
soybean
(
seed)
is
0.1
ppm,
and
is
adequate
to
support
the
both
the
current
and
proposed
uses
of
thifensulfuron
methyl.

d.
Oat
Grain
and
Straw
In
a
study
using
either
0.45
oz
ai/
acre
or
0.90
oz
ai/
acre
thifensulfuron
methyl
on
oats,
samples
of
mature
oat
grain
and
straw
were
taken
from
plots
at
preharvest
intervals
ranging
from
39
to
57
days
after
the
application
of
the
test
substance.
Results
show
that
residues
of
thifensulfuron
methyl
from
9
field
tests
were
below
the
limit
of
detection
(
0.0055
ppm
for
oat
grain,
and
0.018
ppm
for
oat
straw).
Thifensulfuron
methyl
residues
in
2
treated
oat
straw
samples
at
a
California
test
site
showed
residues
of
0.041
and
0.30
mg/
kg,
which
is
above
the
LOQ
of
the
analytical
method.
No
detectable
residues
of
thifensulfuron
methyl
were
found
in
oat
grain
collected
at
that
same
site.

The
current
tolerance
for
thifensulfuron
methyl
on
oat
grain
is
0.05
ppm,
and
on
oat
straw
the
tolerance
is
0.1
ppm.

e.
Canola
and
Flax
Magnitude
of
residue
studies
were
conducted
on
a
variety
of
Canola
containing
the
"
Smart"
 
trait
at
fifteen
test
sites,
and
on
CDC
Triffid
Flax.
All
treatment
plots
received
an
application
at
a
rate
of
0.2
or
0.4
oz.
ai/
acre
as
a
broadcast
foliar
application.
The
canola
variety
containing
the
"
Smart"
 
trait
ranged
from
cotyledon
up
to
the
8
leaf
stage
at
application.
CDC
Triffid
Flax
staging
at
application
ranged
from
5
to
20
cm
in
height.
At
harvest,
no
thifensulfuron
methyl
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
residues
were
found
above
the
limit
of
quantitation
of
0.02
ppm
in
any
seed
samples
treated
with
the
test
substance.

The
current
tolerance
for
thifensulfuron
methyl
on
canola
and
flax
seed
is
0.02
ppm.

f.
Cotton
Seed
and
Gin
Trash
Magnitude
of
the
residue
studies
were
conducted
to
determine
residues
of
thifensulfuron
methyl
in
cotton
seed
and
cotton
gin
trash.
The
study
consisted
of
three
treatments.
Treatment
1:
One
broadcast
application
at
0.3
oz
ai/
A,
applied
approximately
14
days
prior
to
planting.
Treatment
2:
One
broadcast
application
at
0.3
oz
ai/
A,
applied
pre­
plant,
on
the
day
of
planting.
Treatment
3:
One
broadcast
application
at
1.5
oz
ai/
A
(
5X
exaggerated
use
rate),
applied
pre­
plant,
the
day
of
planting.
Pre­
harvest
intervals
(
PHIs)
ranged
from
123
to
196
days.
The
experimentally
determined
limit
of
quantitation
was
0.02
ppm.
The
limit
of
detection
was
estimated
to
be
0.006
ppm.
No
thifensulfuron
methyl
residues
were
found
above
the
limit
of
quantitation
of
0.02
ppm
in
any
cotton
seed
and
cotton
gin
trash
samples
treated
with
the
test
substance.

The
current
tolerance
for
thifensulfuron
methyl
on
cotton
seed
and
cotton
gin
by­
products
is
0.02
ppm.

g.
Rice
Grain
and
Straw
Studies
were
conducted
to
determine
residues
of
thifensulfuron
methyl
in
rice
grain
and
straw.
Two
test
plots
were
established
at
each
site.
One
plot
was
untreated
and
provided
control
samples
for
analysis.
The
other
plot
received
one
pre­
planting
or
at­
planting
application
of
thifensulfuron
methyl
at
a
rate
of
2.25
oz
ai/
acre,
which
was
five
times
the
maximum
expected
label
rate.
Rice
grain
and
straw
samples
were
collected
at
normal
harvest
(
106
­
129
days
after
application)
and
analyzed
for
residues
of
thifensulfuron
methyl.
In
these
exaggerated
rate
studies,
at
normal
harvest,
no
residues
were
detected
(
limit
of
detection
0.02
ppm)
in
any
untreated
control
or
treated
samples
analyzed.

The
proposed
tolerance
for
thifensulfuron
methyl
on
rice
grain
and
straw
is
0.05
ppm.

h.
Grain
Sorghum
Forage,
Stover
and
Grain
Studies
were
conducted
to
determine
residues
of
thifensulfuron
methyl
in
sorghum
forage,
stover,
and
grain.
Two
test
plots
were
established
at
each
site.
One
plot
was
untreated
and
provided
control
samples
for
analysis.
The
other
plot
received
one
pre­
planting
or
at­
planting
application
of
thifensulfuron
methyl
at
a
rate
of
2.25
oz
ai/
acre,
which
was
five
times
the
maximum
expected
label
rate.
Grain
sorghum
forage,
stover,
and
grain
samples
were
collected
at
normal
harvest
(
87­
103
days
after
application
for
forage,
and
133­
144
days
after
application
for
stover
and
grain)
and
analyzed
for
residues
of
thifensulfuron
methyl.
In
these
exaggerated
rate
studies,
at
normal
harvest,
no
residues
were
detected
(
limit
of
detection
0.02
ppm)
in
any
untreated
control
or
treated
samples
analyzed.
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
The
proposed
tolerance
for
thifensulfuron
methyl
on
grain
sorghum
forage,
stover,
and
grain
is
0.05
ppm.

B.
Toxicological
Profile
1.
Acute
Toxicity
Based
on
EPA
criteria,
technical
thifensulfuron
methyl
is
in
acute
toxicity
Category
IV
for
oral
and
inhalation
routes
of
exposure,
and
for
eye
irritation.
Thifensulfuron
methyl
is
in
acute
toxicity
Category
III
for
the
dermal
route
of
exposure
and
for
dermal
irritation.
It
is
not
a
skin
sensitizer.

Acute
oral
toxicity
in
rats
LD50
>
5000
mg/
kg
Acute
dermal
toxicity
in
rabbits
LD50
>
2000
mg/
kg
Acute
inhalation
toxicity
in
rats
LC50
>
7.9
mg/
L
Primary
eye
irritation
in
rabbits
Moderate
irritation
Primary
dermal
irritation
in
rabbits
Slight
irritation
Dermal
sensitization
in
guinea
pigs
Non­
sensitizer
2.
Genotoxicity
Technical
thifensulfuron
methyl
has
shown
no
genotoxic
or
mutagenic
activity
in
the
following
in
vitro
and
in
vivo
tests
:

In
vitro
Mutagenicity
Ames
Assay
Negative
In
vitro
Mutagenicity
CHO/
HPRT
Assay
Negative
In
vitro
Unscheduled
DNA
Synthesis
Negative
In
vivo
Micronuclei
Induction
(
Mouse)
Negative
In
vivo
Bone
Marrow
Chromosome
Aberrations
(
Rat)
Negative
Thifensulfuron
methyl
was
not
mutagenic,
with
or
without
metabolic
activation,
in
an
in
vitro
bacterial
gene
mutation
assay
using
Salmonella
typhimurium.
Thifensulfuron
methyl
also
was
not
mutagenic
in
the
in
vitro
CHO/
HPRT
assay
at
concentrations
up
to
2712
mg/
L
(
in
Chinese
hamster
ovary
cells).
In
cultured
primary
rat
hepatocytes,
thifensulfuron
methyl
was
negative
for
the
induction
of
unscheduled
DNA
synthesis
up
to
2712
mg/
L.

An
in
vivo
bone
marrow
micronucleus
test
was
conducted
in
mice.
There
was
no
increase
in
micronucleated
polychromatic
erythrocytes
(
MNPCE)
frequency
at
a
dose
of
5000
mg/
kg.
An
in
vivo
chromosome
aberration
study
was
conducted
on
rats.
This
included
the
assessment
of
chromosome
aberrations
by
metaphase
analysis
in
bone
marrow
of
male
and
female
rats.
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
Thifensulfuron
methyl
did
not
induce
cytogenic
damage
in
bone
marrow
cells
at
a
dose
of
5000
mg/
kg.

3.
Reproductive
and
Developmental
Toxicity
The
results
of
a
series
of
studies
indicated
that
there
were
no
reproductive,
developmental
or
teratogenic
hazards
associated
with
the
use
of
thifensulfuron
methyl.
In
a
1­
generation
reproduction
study
in
rats,
the
suggested
NOEL
was
7500
ppm
(
559
mg/
kg/
day
males,
697
mg/
kg/
day
females).
In
a
rat
multigeneration
reproduction
study,
the
NOEL
for
reproductive
effects
of
thifensulfuron
methyl
in
adult
rats
and
their
offspring
was
2500
ppm,
the
highest
dietary
level
tested.
This
level
was
based
on
the
absence
of
significant
compound
related
effects
observed
in
this
study,
and
is
equivalent
to
175­
180
mg/
kg/
day
in
adult
male
rats
and
212­
244
mg/
kg/
day
in
adult
female
rats.
There
were
no
effects
on
fertility,
lactation,
litter
size,
or
pup
survival.
Thifensulfuron
methyl
is
not
considered
a
reproductive
toxin.

In
studies
conducted
to
evaluate
developmental
toxicity
potential,
thifensulfuron
methyl
was
neither
teratogenic
nor
uniquely
toxic
to
the
conceptus
(
i.
e.,
not
considered
a
developmental
toxin).
In
the
rat
study,
there
was
no
evidence
of
maternal
toxicity
at
the
highest
dose
tested
(
800
mg/
kg/
day).
Therefore,
the
maternal
NOAEL
is
725
mg/
kg/
day
(
analytically
determined
dose).
The
developmental
NOAEL
for
rats
was
considered
to
be
the
200
mg/
kg/
day
dose
level
(
analytically
determined
and
set
by
EPA
as
159
mg/
kg/
day)
based
on
the
decrease
in
mean
fetal
body
weight
and
an
increase
in
the
incidence
of
small
renal
papillae.
In
the
rabbit
developmental
toxicity
study,
there
was
slight
maternal
toxicity
(
decreased
body
weight
gain)
at
a
dose
of
650
mg/
kg/
day.
No
significant
indications
of
maternal
toxicity
were
evident
at
the
mid­
dose
level
(
200
mg/
kg/
day).
No
compound­
related
effects
on
fetal
weights
or
the
incidences
of
malformations
or
variations
were
seen
at
any
dose.
The
maternal
NOEL
was
the
200
mg/
kg/
day
dose
(
analytically
determined
and
set
by
EPA
at
158
mg/
kg/
day)
and
the
developmental
NOEL
was
the
650
mg/
kg/
day
dose
level
(
analytically
determined
and
set
by
EPA
at
511
mg/
kg/
day)
for
rabbits
dosed
with
thifensulfuron
methyl
by
gavage
on
gestation
days
7­
19.

4.
Subchronic
Toxicity
The
most
sensitive
species
to
subchronic
exposure
of
thifensulfuron
methyl
was
the
rat.
The
NOEL
for
thifensulfuron
methyl
was
100
ppm
(
7
and
9
mg/
kg/
day)
for
male
and
female
rats,
respectively,
in
the
90­
day
dietary
study.
This
was
based
on
the
decreased
body
weight,
food
efficiency,
and
changes
in
clinical
chemistry
in
the
2500
and
7500
ppm
groups.
For
mice
in
both
the
4­
week
range­
finding
and
the
90­
day
studies,
the
NOEL
for
male
and
female
mice
under
the
conditions
of
this
study
was
7500
ppm.
This
was
based
on
the
lack
of
compound­
related
effects
at
the
highest
concentration,
equivalent
to
1427
mg/
kg/
day
in
male
mice
and
2287
mg/
kg/
day
in
female
mice.
EPA
concluded
the
NOEL
for
subchronic
(
90­
day
dietary)
exposure
in
dogs
was
1500
and
7500
ppm
in
males
and
females
(
equivalent
to
37.5
mg/
kg/
day
and
159.7
mg/
kg/
day)
respectively.
These
levels
were
based
on
lower
body
weight
and
adrenal
weight
in
males,
and
a
lack
of
adverse
effects
in
females
at
7500
ppm,
the
highest
concentration
tested.
No
compoundrelated
pathologic
lesions
were
observed
and
no
target
organ
was
identified
in
all
of
the
above
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
tests.

5.
Chronic
Toxicity/
Oncogenicity
The
NOEL
for
chronic
(
2­
year
dietary)
exposure
in
rats
was
500
ppm
(
20
mg/
kg/
day
for
males
and
26
mg/
kg/
day
for
females),
based
on
body
weight
effects
at
2500
ppm.
Thifensulfuron
methyl
was
not
an
oncogen
in
rats.

In
an
18­
month
study
in
mice,
conducted
at
dietary
levels
of
0,
25,
750,
and
7500
ppm,
EPA
concluded
the
NOEL
was
25
ppm
(
4.3
mg/
kg/
day)
based
on
decreased
body
weight
gains
in
female
mice
at
750
ppm
and
above,
and
in
male
mice
at
7500
ppm.
No
other
effects
were
observed
in
the
study.
Thifensulfuron
methyl
was
not
an
oncogen
in
mice.

In
a
1­
year
feeding
study
in
dogs,
the
NOEL
of
thifensulfuron
methyl
was
750
ppm
in
male
and
female
beagle
dogs
(
equivalent
to
approximately
18.75
mg/
kg/
day),
based
on
decreased
body
weights,
body
weight
gains,
and
food
efficiency
in
females
and
increased
liver
weights
in
males,
all
at
7500
ppm.
The
liver
weight
effects
in
males
in
the
absence
of
other
effects
including
histopathology
may
be
adaptive
rather
than
adverse.

6.
Animal
Metabolism
The
metabolic
pathway
for
thifensulfuron
methyl
in
animals
is
understood.
This
metabolic
pathway
involves
hydrolysis
of
the
urea
bridge,
deesterification,
and
O­
demethylation
reactions.
There
was
minimal
potential
for
retention
or
accumulation
of
thifensulfuron
methyl
or
its
metabolites
in
animal
tissues.
Low
levels
of
thifensulfuron
methyl
residues
were
found
in
goat
tissues
and
insignificant
tissue
levels
(
i.
e.,
less
than
0.1%
of
the
dose)
were
observed
in
the
rat.

Rats
were
dosed
with
two
radioactive
forms
of
thifensulfuron
methyl
(
14C­
thiophene
and
14Ctriazine
In
the
thiophene
study,
the
thifensulfuron
methyl
was
primarily
excreted
unchanged
by
rats
following
low
dose
(
20
mg/
kg),
low
dose
following
21
days
dietary
preconditioning
(
100
ppm),
and
high
dose
(
2,000
mg/
kg)
routines.
Approximately
70%
to
85%
of
the
excreted
radioactivity
was
thifensulfuron
methyl.
The
urine
was
the
primary
excretion
route
and
contained
71%
to
92%
of
the
original
dose
from
the
low
and
low­
dose
preconditioned
groups.
Combined
urinary
and
fecal
elimination
was
rapid,
with
over
90%
of
excretion
completed
by
48
hours
after
dosing
for
both
low­
dose
groups.
The
high­
dose
group
peak
elimination
was
delayed
by
approximately
24
hours
compared
to
the
other
dose
levels.
Tissue
radioactivity
levels
were
low
at
sacrifice
(
96
hours
after
dosing)
for
all
dosing
groups,
with
no
enhanced
retention
of
radioactivity
by
any
organ
or
tissue.
Thifensulfuron
methyl
was
the
primary
radiolabeled
excretion
product
with
thifensulfuron
acid,
2­
acid­
3­
sulfonamide,
2­
ester­
3­
sulfonamide,
and
thiophene
sulfonamide
identified
as
minor
metabolites.

In
the
triazine
study,
thifensulfuron
methyl
was
excreted
primarily
unchanged
in
urine
and
feces
by
male
and
female
rats
after
administration
of
approximately
2000
mg/
kg
by
oral
gavage.
Urine
was
the
primary
route
of
excretion,
averaging
58.7%
of
the
dose
in
males
and
75.5%
in
females.
Fecal
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
excretion
of
the
dose
averaged
21.2%
for
the
male
rats
and
15.8%
for
the
females.
Greater
than
50%
of
the
dose
was
excreted
by
48
hours
post­
dosing.
Essentially
no
elimination
of
the
dose
as
radiolabeled
CO2
or
volatile
compounds
occurred.
These
results
are
similar
to
those
reported
on
the
thiophene­
labeled
thifensulfuron
methyl.
Intact
thifensulfuron
methyl
was
identified
by
mass
spectrometry
as
the
principal
radioactive
compound
in
urine
(>
94%)
and
feces
(>
77%).
Three
minor
metabolites,
each
less
than
3%
of
the
dose,
were
identified
in
urine
and
feces
by
chromatographic
retention
comparison;
they
were
thifensulfuron
acid,
O­
demethyl
thifensulfuron
methyl,
and
triazine
amine.

Results
from
a
metabolism
study
with
two
radioactive
forms
of
thifensulfuron
methyl
(
14C­
triazine
and
14C­
thiophene)
in
lactating
goats
show
that
most
of
the
dosed
radioactivity
was
rapidly
excreted
(
primarily
in
the
urine)
and
recovered
as
intact
thifensulfuron
methyl.
Radioactivity
in
the
milk
(
0.1
­
0.2
ppm)
was
comprised
of
mostly
intact
thifensulfuron
methyl
and
a
small
amount
of
triazine
amine
and
several
very
minor
metabolites.
Radioactivity
did
not
accumulate
in
the
tissues.
After
absorption,
the
major
metabolic
pathway
involved
cleavage
of
the
carboxyl
ester
linkage,
resulting
in
the
formation
of
thifensulfuron
acid.
Oxidative
O­
demethylation
occurred
to
a
limited
extent.

There
were
no
significant
levels
of
unique
plant
metabolites
of
thifensulfuron
methyl
found
in
food
or
feed
products
at
crop
maturity.
Hence,
toxicity
testing
of
other
degradation
products
of
thifensulfuron
methyl
is
not
needed.

7.
Metabolite
Toxicology
There
is
no
evidence
that
the
metabolites
of
thifensulfuron
methyl,
as
identified
in
either
the
plant
or
animal
metabolism
studies,
are
of
any
toxicological
significance.

8.
Endocrine
Effects
No
special
studies
investigating
potential
estrogenic
or
other
endocrine
effects
of
thifensulfuron
methyl
have
been
conducted.
However,
the
standard
battery
of
required
toxicology
studies
has
been
completed.
These
include
an
evaluation
of
the
potential
effects
on
reproduction
and
development,
and
an
evaluation
of
the
pathology
of
the
endocrine
organs
following
repeated
or
long­
term
exposure
to
doses
that
far
exceed
likely
human
exposures.
Based
on
these
studies,
there
is
no
evidence
to
suggest
that
thifensulfuron
methyl
has
an
adverse
effect
on
the
endocrine
system.

C.
Aggregate
Exposure
Thifensulfuron
methyl
is
the
active
ingredient
in
a
number
of
DuPont
herbicides,
with
new
uses
being
proposed
for
pre­
plant
or
at­
planting
herbicidal
treatment
for
soybeans,
field
corn,
rice,
and
sorghum.
There
are
no
residential
uses
for
any
thifensulfuron
methyl
containing
herbicides.
1.
Dietary
Exposure
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
The
chronic
reference
dose
(
cRfD)
of
0.2
mg/
kg/
day
is
based
on
the
NOEL
of
20
mg/
kg/
day
from
a
two­
year
rat
feeding
study
and
a
100X
safety
factor.
The
acute
reference
dose
(
aRfD)
of
1.59
mg/
kg/
day
is
based
the
NOEL
of
159
mg/
kg/
day
from
a
rat
developmental
study
and
a
100X
safety
factor.

The
residue
of
concern,
as
listed
at
40
CFR
180.439,
is
parent
thifensulfuron
methyl
only.

2.
Food
a.
Chronic
Dietary
Exposure
Assessment
Dietary
exposure,
resulting
from
the
current
and
proposed
uses
of
thifensulfuron
methyl
on
barley,
canola,
cotton,
flax,
field
corn,
oats,
soybeans,
sorghum,
rice
and
wheat,
is
well
within
the
acceptable
limits
for
all
sectors
of
the
population,
as
predicted
by
both
the
Chronic
and
Acute
Modules
of
the
Dietary
Exposure
Evaluation
Model
(
DEEM,
Exponent,
Inc.,
2003
Version
7.87).
The
percentage
or
proportion
of
a
crop
that
is
treated
can
have
a
significant
effect
on
the
exposure
profile.
In
this
case,
it
was
assumed
for
all
crops
that
100%
was
treated
with
thifensulfuron
methyl.
Based
on
a
comparison
with
the
actual
use
profiles
for
herbicides
containing
thifensulfuron
methyl,
this
is
an
extremely
conservative
estimate.

The
predicted
chronic
exposure
for
the
U.
S.
population
subgroup
was
0.0000151
mg/
kg
bw/
day.
The
population
subgroup
with
the
highest
predicted
level
of
chronic
exposure
was
the
nonnursing
infants
subgroup
with
an
exposure
of
0.0000401
mg/
kg
bw/
day.
Based
on
a
chronic
NOEL
of
20
mg/
kg
bw/
day
and
a
100­
fold
safety
factor,
the
cRfD
would
be
0.2
mg/
kg
bw/
day.
For
the
U.
S.
population,
the
predicted
exposure
is
equivalent
to
less
than
1%
of
the
cRfD.
For
the
population
subgroup
with
the
highest
level
of
exposure
(
non­
nursing
infants),
the
exposure
would
also
be
equivalent
to
less
than
1%
of
the
cRfD.
Because
the
predicted
exposures,
expressed
as
percentages
of
the
cRfD,
are
well
below
100%,
there
is
reasonable
certainty
that
no
chronic
effects
would
result
from
dietary
exposure
to
thifensulfuron
methyl.

b.
Acute
Dietary
Exposure
The
predicted
acute
exposure
for
the
U.
S.
population
subgroup
was
0.000595
mg/
kg
bw/
day
(
95th
percentile).
The
population
subgroup
with
the
highest
predicted
level
of
acute
exposure
was
the
non­
nursing
infants
subgroup
with
an
exposure
of
0.001437
mg/
kg
bw/
day
(
95th
percentile).
Based
on
an
acute
NOEL
of
159
mg/
kg
bw/
day
and
a
100­
fold
safety
factor,
the
aRfD
would
be
1.59
mg/
kg
bw/
day.
For
the
U.
S.
population
the
predicted
exposure
(
at
the
95th
percentile)
is
equivalent
to
0.04%
of
the
aRfD.
For
the
population
subgroup
with
the
highest
level
of
exposure
(
non­
nursing
infants
subgroup),
the
exposure
(
at
the
95th
percentile)
would
be
equivalent
to
0.09%
of
the
aRfD.
Because
the
predicted
exposures,
expressed
as
percentages
of
the
aRfD,
are
well
below
100%,
there
is
reasonable
certainty
that
no
acute
effects
would
result
from
dietary
exposure
to
thifensulfuron
methyl.

3.
Drinking
Water
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
Surface
water
exposure
was
estimated
using
the
Generic
Expected
Environmental
Concentration
(
GENEEC)
model.
Groundwater
exposures
were
estimated
using
SCI­
GROW.

The
EPA
uses
drinking
water
levels
of
comparison
(
DWLOCs)
as
a
surrogate
measure
to
capture
risk
associated
with
exposure
to
pesticides
in
drinking
water.
A
DWLOC
is
the
concentration
of
a
pesticide
in
drinking
water
that
would
be
acceptable
as
an
upper
limit
in
light
of
total
aggregate
exposure
to
that
pesticide
from
food,
water,
and
residential
uses.
A
DWLOC
will
vary
depending
on
the
residue
level
in
foods,
the
toxicity
endpoint,
and
with
drinking
water
consumption
patterns
and
body
weights
for
specific
subpopulations.

The
acute
DWLOCs
are
56
ppm
(
parts
per
million)
for
adult
males,
48
ppm
for
adult
females,
and
16
ppm
for
the
subpopulation
with
the
highest
exposure
(
non­
nursing
infants).
The
estimated
maximum
concentration
of
thifensulfuron
methyl
in
surface
water
(
1.2
parts
per
billion,
or
ppb)
derived
from
GENEEC
is
much
lower
than
the
acute
DWLOCs.
Therefore,
one
can
conclude
with
reasonable
certainty
that
residues
of
thifensulfuron
methyl
in
drinking
water
do
not
contribute
significantly
to
the
aggregate
acute
human
health
risk.

The
chronic
DWLOCs
are
0.45
ppm
for
adult
males,
0.38
ppm
for
adult
females,
and
0.12
ppm
for
the
subpopulation
with
the
highest
exposure
(
non­
nursing
infants).
These
DWLOC
values
are
substantially
higher
than
the
GENEEC
56­
day
estimated
environmental
concentration
of
0.65
ppb
for
thifensulfuron
methyl
in
surface
water.
Therefore,
one
can
conclude
with
reasonable
certainty
that
residues
of
thifensulfuron
methyl
in
drinking
water
do
not
contribute
significantly
to
the
aggregate
chronic
human
health
risk.

4.
Non­
Dietary
Exposure
Thifensulfuron
methyl
is
not
registered
for
any
use
which
could
result
in
non­
occupational
or
nondietary
exposure
to
the
general
population.

D.
Cumulative
Effects
Thifensulfuron
methyl
belongs
to
the
sulfonylurea
class
of
crop
protection
chemicals.
Other
structurally
similar
compounds
in
this
class
are
registered
as
herbicides.
However,
the
herbicidal
activity
of
sulfonylureas
is
due
to
the
inhibition
of
acetolactate
synthase
(
ALS),
an
enzyme
found
only
in
plants.
This
enzyme
is
part
of
the
biosynthesis
pathway
leading
to
the
formation
of
branched
chain
amino
acids.
Animals
lack
ALS
and
this
biosynthetic
pathway.
This
lack
of
ALS
contributes
to
the
relatively
low
toxicity
of
sulfonylurea
herbicides
in
animals.
There
is
no
reliable
information
that
would
indicate
or
suggest
that
thifensulfuron
methyl
has
any
toxic
effects
on
mammals
that
would
be
cumulative
with
those
of
any
other
chemical.

E.
Safety
Determination
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
Based
on
data
and
information
submitted
by
DuPont,
EPA
previously
determined
that
the
establishment
of
tolerances
of
thifensulfuron
methyl
on
the
barley,
oats,
wheat,
field
corn,
cotton,
canola,
flax,
and
soybean
raw
agricultural
commodities
would
protect
the
public
health,
including
the
health
of
infants
and
children.

Establishment
of
new
tolerances
for
thifensulfuron
methyl
on
Rice
grain
at
0.05
ppm,
Rice
straw
at
0.05
ppm,
Grain
sorghum
grain
at
0.05
ppm,
Grain
sorghum
forage
at
0.05
ppm,
and
Grain
sorghum
stover
at
0.05
ppm
will
also
not
adversely
impact
public
health.

1.
U.
S.
Population
Based
on
the
completeness
and
reliability
of
the
toxicology
database,
and
using
the
conservative
assumptions
presented
earlier,
EPA
has
established
a
cRfD
of
0.2
mg/
kg/
day.
This
was
based
on
the
NOEL
for
the
chronic
rat
study,
20
mg/
kg/
day,
and
a
100­
fold
safety
factor.
It
has
been
concluded
that
the
chronic
dietary
exposure
was
less
than
1%
of
the
cRfD.
Generally,
exposures
below
100%
of
the
cRfD
are
of
no
concern
because
it
represents
the
level
at
or
below
which
daily
dietary
exposure
over
a
lifetime
will
not
pose
appreciable
risk
to
human
health.
Thus,
there
is
reasonable
certainty
that
no
harm
will
result
from
chronic
exposures
to
thifensulfuron
methyl
residues.

2.
Infants
and
Children
In
assessing
the
potential
for
additional
sensitivity
of
infants
and
children
to
residues
of
thifensulfuron
methyl,
data
from
the
previously
discussed
developmental
and
multigeneration
reproductive
toxicity
studies
were
considered.

Developmental
studies
are
designed
to
evaluate
adverse
effects
on
the
developing
organism
resulting
from
pesticide
exposure
during
pre­
natal
development.
Reproduction
studies
provide
information
relating
to
reproductive
and
other
effects
on
adults
and
offspring
from
pre­
natal
and
post­
natal
exposures
to
the
pesticide.
The
studies
with
thifensulfuron
methyl
demonstrated
no
evidence
of
developmental
toxicity
at
exposures
below
those
causing
maternal
toxicity.
This
indicates
that
developing
animals
are
not
more
sensitive
to
the
effects
of
thifensulfuron
methyl
administration
than
adults.

FFDCA
section
408
provides
that
EPA
may
apply
an
additional
uncertainty
factor
for
infants
and
children
in
the
case
of
threshold
effects
to
account
for
pre­
and
post­
natal
toxicity
and
the
completeness
of
the
database.
Based
on
current
toxicological
data
requirements,
the
database
for
thifensulfuron
methyl
relative
to
pre­
and
post­
natal
effects
for
children
is
complete.
In
addition,
the
NOEL
of
20
mg/
kg/
day
in
the
chronic
rat
study
(
and
upon
which
the
RfD
is
based)
is
much
lower
than
the
NOELs
defined
in
the
reproduction
and
developmental
toxicology
studies.
The
sub­
population
with
the
highest
level
of
exposure
was
Non­
Nursing
Infants
(<
1
yr),
where
exposure
was
less
than
1%
of
the
cRfD.
Based
on
these
conservative
analyses,
there
is
reasonable
certainty
that
no
harm
will
result
to
infants
and
children
from
aggregate
exposures
to
thifensulfuron
methyl.
Pesticide
Petition
for
Tolerances
for
AGRICULTURAL
COMMODITIES
Thifensulfuron
Methyl
Sorghum
and
Rice
Copyright
by
E.
I.
du
Pont
de
Nemours
and
Company
Wilmington,
DE
19880­
0038
(
August
2004)
F.
International
Tolerances
The
maximum
residue
limit
(
MRL)
in
Canada
for
thifensulfuron
methyl
on
canola
is
0.1
ppm.
The
MRLs
in
the
EU
(
European
Union)
are
0.05
ppm
for
barley,
field
corn
(
maize),
oats,
soybeans
(
soya
bean),
wheat,
canola
(
rapeseed),
cotton
seed,
flax
(
other
oilseeds),
rice,
sunflowers,
and
sorghum.

(
FR
Notice
 
Thifensulfuron,
Draft
1.
December
6,
2004)
