1
United
States
Prevention,
Pesticides
December
2004
Environmental
Protection
and
Toxic
Substances
Agency
(
7508C)

Report
of
the
Food
Quality
Protection
Act
(
FQPA)
Tolerance
Reassessment
Progress
and
Risk
Management
Decision
(
TRED)
for
Nicosulfuron
2
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
CERTIFIED
MAIL
Dear
Registrant:

This
is
the
Environmental
Protection
Agency's
(
hereafter
referred
to
as
EPA
or
the
Agency)
"
Report
of
the
Food
Quality
Protection
Act
(
FQPA)
Tolerance
Reassessment
Progress
and
Risk
Management
Decision
for
Nicosulfuron,"
which
was
approved
December
2004.
This
document
is
also
known
as
a
Tolerance
Reassessment
Decision,
or
TRED.
A
Notice
of
Availability
of
this
tolerance
reassessment
decision
will
be
published
shortly.

The
Federal
Food,
Drug
and
Cosmetic
Act
(
FFDCA),
as
amended
by
FQPA,
requires
EPA
to
reassess
all
the
tolerances
for
registered
chemicals
in
effect
on
or
before
the
enactment
of
the
FQPA
on
August
3,
1996.
In
reassessing
these
tolerances,
the
Agency
must
consider,
among
other
things,
aggregate
risks
from
non­
occupational
sources
of
pesticide
exposure,
whether
there
is
increased
susceptibility
to
infants
and
children,
and
the
cumulative
effects
of
pesticides
with
a
common
mechanism
of
toxicity.
Once
a
safety
finding
has
been
made,
the
tolerances
are
considered
reassessed.
Existing
tolerances
and
exemptions
associated
with
nicosulfuron
must
be
reassessed
in
accordance
with
FFDCA,
as
amended
by
FQPA.

The
Agency
has
evaluated
all
current
registered
uses
of
nicosulfuron
and
has
determined
that
there
is
a
reasonable
certainty
that
no
harm
to
any
population
subgroup
will
result
from
exposure
to
nicosulfuron
when
considering
dietary
exposure
and
all
other
non­
occupational
sources
of
pesticide
exposure
for
which
there
is
reliable
information.
Therefore,
no
mitigation
measures
are
needed
and
current
tolerances
at
40
CFR
180.454
for
nicosulfuron
are
now
considered
reassessed
under
section
408(
q)
of
the
FFDCA.
All
tolerances
were
reassessed
and
maintained
at
0.1
ppm.

Nicosulfuron
is
a
sulfonyl
urea
herbicide
registered
for
early­
postemergent
and
postemergent
use
on
corn.
It
may
be
used
alone
or
in
formulation
with
other
active
ingredients
to
control
annual
and
perennial
grasses
and
broadleaf
weeds.
Application
methods
include
band
treatment,
broadcast,
low
volume
spray
(
concentrate)
using
aircraft,
or
ground
equipment.
The
maximum
application
rate
is
0.06248
lb
a.
i./
acre.
The
highest
usage
of
nicosulfuron
is
on
corn
and
approximately
200,000
pounds
are
used
annually.
3
Nicosulfuron
is
in
Toxicity
Category
IV
for
acute
oral,
inhalation,
and
dermal
irritation.
It
is
Toxicity
Category
III
for
acute
dermal
and
acute
eye
irritation.
Nicosulfuron
is
not
likely
to
be
carcinogenic
based
on
bioassays
in
the
rat
and
mouse
and
lack
of
in
vitro
and
in
vivo
mutagenic
effects.
Nicosulfuron
showed
no
developmental
or
reproductive
effects
in
rats
and
developmental
effects
in
rabbits
only
at
high
doses.
There
were
no
indications
of
neurotoxic
effects
elicited
by
nicosulfuron
in
animal
tests.

For
acute
dietary,
an
endpoint
of
concern
attributable
to
a
single
dose
was
not
identified.
Acute
studies
showed
no
affect
at
high
doses.
Therefore,
a
risk
assessment
for
this
exposure
was
not
performed
and
a
toxic
endpoint
derived
from
a
chronic
study
was
considered
the
most
appropriate
for
risk
assessment
purposes.

For
the
chronic
dietary
risk
assessment,
a
chronic
dog
feeding
study
with
a
No
Observable
Adverse
Effect
Level
(
NOAEL)
of
125
mg/
kg/
day
and
a
Lowest
Observed
Adverse
Effect
Dose
(
LOAEL)
of
500
mg/
kg/
day
was
used.
All
population
subgroups'
Chronic
Population
Adjusted
Dose
(%
cPAD)
are
less
than
1%
which
is
below
the
Agency's
Level
of
Concern
(
LOC).

In
addition,
for
chronic
aggregate
exposure
(
food
+
water),
nicosulfuron
dietary
exposure
and
risk
is
below
EPA's
level
of
concern.
The
level
of
refinement
of
the
analyses
is
Tier
1
or
tolerance
level
without
any
percent
crop
treated
information.
EPA's
LOC
for
the
aggregate
is
not
exceeded
for
all
population
subgroups
including
the
general
U.
S.
population
for
the
chronic
analyses.
The
population
subgroup,
children
ages
3­
5,
utilizes
the
highest
percentage
of
the
cPAD
and
constitutes
less
than
1%.

There
are
no
residential
uses
that
might
contribute
to
aggregate
risks,
and
occupational
exposure
is
not
assessed
in
this
TRED.
There
are
no
unfulfilled
data
requirements
for
nicosulfuron.

The
nature
of
the
residue
in
plants
and
livestock
is
adequately
understood
based
on
metabolism
studies
with
corn
and
goats.
The
residue
of
concern
for
both
risk
assessment
and
tolerance
enforcement
purposes
is
nicosulfuron
per
se.
Seven
tolerances
for
corn
scenarios
(
all
set
at
0.1
ppm)
are
established
under
40
CFR
§
180.454
for
residues
of
nicosulfuron
[
3­
pyridinecarboxamide,
2­
((((
4,6­
dimethoxypyrimidin­
2­
yl)
aminocarbonyl)
aminosulfonyl))
­
N,
N­
dimethyl].
There
are
no
tolerances
established
for
nicosulfuron
residues
in
livestock
tissues,
milk
or
eggs
as
the
Agency
has
concluded
that
there
is
no
reasonable
expectation
of
finite
residues
(
40
CFR
§
180.6(
a)(
3))
of
nicosulfuron
in
livestock
commodities
based
on
the
current
registered
uses
in
or
on
livestock
feed
commodities
that
might
result
in
nicosulfuron
residues.
Therefore,
the
seven
existing
tolerances
for
nicosulfuron
are
considered
reassessed
under
Section
408(
q)
of
the
FFDCA.

FQPA
requires
that
EPA
consider
"
available
information"
concerning
the
cumulative
effects
of
a
particular
pesticide's
residues
and
"
other
substances
that
have
a
common
mechanism
of
toxicity."
The
Agency
considers
other
substances
because
low­
level
exposures
to
multiple
chemical
substances
that
cause
a
common
toxic
effect
by
a
common
mechanism
could
lead
to
the
same
adverse
health
4
effect,
as
would
a
higher
level
of
exposure
to
any
of
the
other
substances
individually.

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
nicosulfuron
and
any
other
substances
and
nicosulfuron
does
not
appear
to
produce
a
toxic
metabolite
produced
by
other
substances.
For
the
purposes
of
this
tolerance
action,
therefore,
EPA
has
not
assumed
that
nicosulfuron
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/.

Based
on
currently
available
data,
nicosulfuron
does
not
appear
to
be
an
endocrine
disruptor.
However,
when
the
appropriate
screening
and/
or
testing
protocols
being
considered
under
the
Agency's
Endocrine
Disruptor
Screening
Program
have
been
developed,
nicosulfuron
may
be
subjected
to
additional
screening
and/
or
testing
to
better
characterize
effects
related
to
endocrine
disruption.

This
document
summarizes
the
Agency's
decision
on
the
tolerance
reassessment
for
nicosulfuron.
Please
contact
Meghan
French
of
my
staff
with
any
questions
regarding
this
decision.
She
may
be
reached
by
phone
at
(
703)
308­
8004
or
by
e­
mail
at
french.
meghan@
epa.
gov.

Sincerely,

Debra
Edwards,
Ph.
D.
Director
Special
Review
and
Reregistration
Division
Enclosures:
Nicosulfuron
Risk
Assessment
Document
5
6
