Document ID: EPA-HQ-OPP-2004-0219-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-09-14T04:00Z

UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
DP
Barcode:
D330621
PC
Code:
118601
Date:
September
10,
2004
MEMORANDUM
SUBJECT:
Ecological
Risk
Assessment
in
Support
of
the
Reregistration
Eligibility
Decision
for
Chlorsulfuron
TO:
Susan
Jennings,
Chemical
Review
Manager
Michael
Goodis,
Product
Manager
Special
Review
and
Reregistration
Division
FROM:
Dirk
Y.
Young,
Ph.
D.,
Environmental
Engineer
Dan
Balluff,
Wildlife
Biologist
Environmental
Risk
Branch
4
THROUGH:
Elizabeth
Behl,
Chief
Environmental
Risk
Branch
4
Environmental
Fate
and
Effects
Division
The
Environmental
Fate
and
Effects
Division
(
EFED)
has
revised
its
ecological
risk
assessment
of
chlorsulfuron
in
response
to
the
30­
day
error
correction
comments
(
DP
Barcode
D295494)
received
from
the
technical
registrant.
Based
on
available
data,
exposure
to
terrestrial
or
aquatic
animals
is
not
expected
to
exceed
either
acute
or
chronic
levels
of
concern
(
LOC's).
However,
the
chlorsulfuron
uses
modeled
in
the
assessment
exceed
acute
risk
levels
of
concern
for
non­
target
plants
by
over
three
orders
of
magnitude
while
LOC's
for
threatened/
endangered
plants
are
exceeded
by
over
four
orders
of
magnitude.
Additionally,
estimated
peak
concentrations
in
surface
and
groundwater­
derived
drinking
water
are
1.9

g/
L
and
1.6

g/
L,
respectively.
If
you
have
any
questions
regarding
this
document,
please
do
not
hesitate
to
contract
the
risk
assessors.
Page
i
of
90
REGISTRATION
ELIGIBILITY
DECISION
September
10,
2004
(
revised)

ENVIRONMENTAL
FATE
AND
ECOLOGICAL
EFFECTS
RISK
ASSESSMENT
for
CHLORSULFURON
Environmental
Fate
and
Effects
Division,
Environmental
Risk
Branch
IV:

Dan
Balluff
Dirk
Young
Peer
Reviewers:

Leo
LaSota
Norman
Birchfield
Branch
Chief:

Elizabeth
Behl
DP
Barcode:
D330621
PC
Code:
118601
Page
ii
of
90
Table
of
Contents
EXECUTIVE
SUMMARY
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iv
Chlorsulfuron
Usage
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iv
Chlorsulfuron
Risk
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iv
Toxicity
and
Risk
to
Non­
target
and
Endangered
Plants
.
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iv
Field
Studies
and
Greenhouse
Studies
.
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v
Non­
target
Plant
Incident
Reports
.
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v
Endangered
Plant
Species
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.
v
Drinking
Water
Assessment
for
Human
Health
.
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v
PROBLEM
FORMULATION
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1
Conceptual
Model
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1
Identification
and
Mechanism
of
Action
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1
Use
Characterization
and
Formulations
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2
Rate
and
Method
of
Application
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2
Current
Label
Restrictions
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3
Assessment
Endpoints
and
Analysis
Plan
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5
ENVIRONMENTAL
FATE
CHARACTERIZATION
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6
Chlorsulfuron
Fate
Studies
.
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7
Hydrolysis
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7
Photodegradation
in
Water
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7
Soil
Photodegradation
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7
Aerobic
Soil
Metabolism
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7
Anaerobic
Aquatic
Metabolism
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8
Bioaccumulation
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8
Field
Dissipation
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8
Sorption
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8
Water
Resource
Assessment
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9
Ambient
Surface
Water
(
Farm
Pond)
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9
Drinking
Water
Assessment
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11
Surface
Water
Source
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11
Ground
Water
Source
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12
Drinking
Water
Estimated
Concentrations
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12
ECOLOGICAL
EFFECTS
CHARACTERIZATION
.
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13
Toxicological
Profile
for
Terrestrial
and
Aquatic
Animals
.
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13
Risk
Quotients
for
Terrestrial
and
Aquatic
Animals
.
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15
Birds
and
Mammals
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15
Freshwater
and
Marine/
estuarine
Fish
and
Invertebrates
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15
Page
iii
of
90
Risk
Characterization
for
Terrestrial
and
Aquatic
Wildlife
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16
Plant
Effects
Assessment
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16
Toxicological
Profile
for
Terrestrial
and
Aquatic
Plants
.
.
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.
16
Risk
Quotients
for
Aquatic
and
Terrestrial
Plants
.
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18
Aquatic
Plant
Assessment
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18
Terrestrial
Plant
Assessment
.
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18
Terrestrial
Plant
Assessment
for
Contaminated
Irrigation
Water
.
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25
Toxicity
Studies
(
from
Public
Literature)
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25
Fletcher
et
al.
1995
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26
Coyner
et
al.
2000
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26
Field
Studies,
Greenhouse
Studies,
and
Incident
Reports
.
.
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26
Field
Studies
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27
Fletcher
et
al.
1993
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27
Bhatti
et
al.
1995
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27
Greenhouse
Studies
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28
Non­
target
Plant
Incident
Reports
.
.
.
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29
Risk
Characterization
for
Terrestrial
and
Aquatic
Plants
.
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.
30
Plants
Exposed
to
Chlorsulfuron
Drift
.
.
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.
32
Plants
in
Semi­
Aquatic
Areas
(
Wetlands)
.
.
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.
33
Terrestrial
Plants
(
Seedling
Emergence)
.
.
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.
34
Terrestrial
Plants
(
Vegetative
Vigor)
.
.
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.
34
Plants
Exposed
to
Irrigation
Water
Containing
Chlorsulfuron
.
.
.
.
.
.
.
.
.
.
.
.
.
.
35
Aquatic
Plants
.
.
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.
.
36
Refined
Assessment
of
Spray
drift
on
non­
target
Terrestrial
Plants
.
.
.
.
.
.
.
.
.
.
36
ENDANGERED/
THREATENED
SPECIES
.
.
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50
REFERENCES
.
.
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.
51
APPENDIX
1.
PRZM
and
EXAMS
input
files
.
.
.
.
.
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.
53
APPENDIX
2.
SUMMARY
OF
CHLORSULFURON
TOXICITY
TESTS
FOR
TERRESTRIAL
AND
AQUATIC
ANIMALS.
.
.
.
.
.
.
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.
64
APPENDIX
3.
ESTIMATED
ENVIRONMENTAL
CONCENTRATIONS
ON
AVIAN
AND
MAMMALIAN
FOOD
ITEMS
(
ppm)
FOLLOWING
A
SINGLE
APPLICATION
AT
1
LB
a.
i./
A
.
.
.
.
.
.
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.
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.
67
APPENDIX
4.
NON­
TARGET
TERRESTRIAL
PLANT
SEEDLING
EMERGENCE
TOXICITY
(
TIER
II)
FOR
98.2%
CHLORSULFURON
WITH
BUFFER
AND
VALENT
X­
77
SURFACTANT
IN
SOME
SOLUTIONS.
.
.
.
.
.
.
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.
68
Page
iv
of
90
APPENDIX
5.
NON­
TARGET
TERRESTRIAL
PLANT
VEGETATIVE
VIGOR
TOXICITY
(
TIER
II)
FOR
98.2%
CHLORSULFURON
WITH
BUFFER
AND
VALENT
X­
77
SURFACTANT
IN
SOME
SOLUTIONS.
.
.
.
.
.
.
.
.
.
.
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.
69
APPENDIX
6.
RQ
CALCULATIONS
FOR
SURFACE
AND
GROUNDWATER
IRRIGATION
.
.
.
.
.
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.
70
APPENDIX
7.
FIRST
ORDER
DEGRADATION
FOR
CHLORSULFURON
.
.
.
.
.
.
.
.
.
.
.
.
71
APPENDIX
8.
TIER
1
DRINKING
WATER
ASSESSMENT
MEMORANDUM
.
.
.
.
.
.
.
.
.
72
APPENDIX
9a
SURVEY
OF
AERIAL
APPLICATORS
TO
DETERMINE
TYPICAL
AIRCRAFT
SETUPS
.
.
.
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.
81
APPENDIX
9b
PHYTOTOXICITY
RESULTING
FROM
SPRAY
DRIFT
DURING
A
MEDIUM
APPLICATION
RATE
.
.
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.
83
APPENDIX
9c
PHYTOTOXICITY
RESULTING
FROM
SPRAY
DRIFT
DURING
A
MEDIUM
APPLICATION
RATE
.
.
.
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89
Page
v
of
90
EXECUTIVE
SUMMARY
Chlorsulfuron
Usage
Chlorsulfuron
is
a
broad
spectrum,
pre­
emergent
and
post­
emergent
sulfonylurea
herbicide
used
on
small
grains
such
as
wheat,
barley
and
oats.
It
is
also
registered
for
use
on
pastures,
rangeland
and
fallow.
Non­
crop
sites
include:
unimproved
turf,
industrial
turf,
industrial
sites,
ornamentals,
and
noncrop
restoration.
Chlorsulfuron
is
applied
to
agricultural
crops
as
a
spray
by
aircraft
or
ground
equipment
at
single
application
rates
ranging
from
0.0078
to
0.0625
lbs
ai/
acre;
application
rates
to
non­
crop
sites
are
the
highest,
ranging
from
0.0078
to
0.25
lbs
ai/
acre(
Table
1).
Chlorsulfuron
may
be
tank­
mixed
with
other
sulfonylurea
herbicides.

Chlorsulfuron
Risk
The
results
of
this
screening
level
ecological
risk
assessment
indicate
that
chlorsulfuron
exceeds
EFED's
Levels
of
Concern
(
LOC)
for
non­
target
plants
by
over
three
orders
of
magnitude.
LOCs
for
endangered
plants
are
exceeded
by
over
four
orders
of
magnitude.
Risk
quotients
(
RQs)
were
calculated
using
seedling
emergence,
vegetative
vigor
and
aquatic
plant
laboratory
toxicity
tests.
Based
on
available
data,
exposure
to
mammals,
birds,
and
aquatic
organisms
are
not
expected
to
exceed
either
acute
or
chronic
risk
levels
of
concern
(
Table
8).
Exposure
scenarios
were
based
on
exposure
via
spray
drift,
surface
runoff,
and
irrigation.

Toxicity
and
Risk
to
Non­
target
and
Endangered
Plants
Chlorsulfuron
is
toxic
to
non­
target
plants
with
EC
25
equivalent
to
an
application
rate
4
x10
­
6
lbs
a.
i./
acre
and
an
EC
05
EC
05
equivalent
to
an
application
rate
4.6
x
10
­
8
lbs
a.
i.
/
acre
based
on
vegetative
vigor
studies
of
the
herbicide.
A
single
aerial
application
of
chlorsulfuron,
assuming
5%
of
the
applied
drifts
into
non­
target
areas,
results
in
screening
level
RQs
ranging
from
267
to
1042
for
non­
target
plants
and
from
17,532
to
68,488
for
endangered
plants
(
Tables
11
and
13).
Additionally,
for
fields
irrigated
with
ground
or
surface
water
contaminated
with
chlorsulfuron,
non­
endangered
plant
RQs
range
from
91
to
341
(
Table
14).
In
regions
where
chlorsulfuron
has
been
used
historically,
modeling
results
indicate
that
groundwater
and
surface
water
irrigation
may
result
in
damage
to
agricultural
crops
that
are
sensitive
to
chlorsulfuron.

The
risk
to
nontarget
plants
from
direct
application
of
chlorsulfuron
has
not
been
estimated
quantitatively
in
this
risk
assessment,
but
are
expected
to
be
higher
than
those
estimated
for
indirect
exposure
through
runoff
and
drift.
In
addition,
risk
from
use
on
golf
courses,
sod
farms,
and
nurseries
were
not
assessed
quantitatively
(
as
usage
is
low)
but
estimated
risk
would
be
higher
as
application
rates
for
those
uses
are
higher.

A
refined
assessment
was
conduced
on
effects
of
chlorsulfuron
spray
drift
on
non­
target
plants.
Refinements
are
intended
to
accurately
reflect
the
most
important
application
conditions
actually
used
in
applying
chlorsulfuron.
To
estimate
a
range
of
spray
drift
levels,
application
parameters
employed
by
aerial
applicators
in
Washington
and
Oregon
were
used;
ground
boom
configurations
were
Page
vi
of
90
assumed
to
include
the
range
of
values
available
in
the
AgDRIFT
model.
Risks
to
non­
target
plants
resulting
from
spray
drift
from
ground
and
aerial
applications
of
chlorsulfuron
are
dependent
upon
a
number
of
factors.
This
analysis
suggests
that
most
plant
species
are
likely
to
be
affected
at
low
levels
(
10%
reductions
in
shoot
weight)
more
than
1000
feet
downwind
of
applications
conducted
in
winds
speeds
of
10
mph.
Under
certain
conditions,
80%
effect
levels
may
occur
to
more
sensitive
species
at
1000
feet
or
more
downwind.
Higher
effect
levels
are
triggered
more
frequently
by
aerial
applications
than
with
ground
boom
applications
and
more
frequently
with
finer
sprays.

Field
Studies
and
Greenhouse
Studies
A
number
of
field
studies
have
been
conducted
with
chlorsulfuron
(
see
Section
3.7).
Several
researchers
have
concluded
that
small
quantities
of
the
chemical,
such
as
might
be
found
in
airborne
particles
traveling
long
distances,
may
affect
plant
reproduction
without
altering
vegetative
growth.
If
the
effect
of
chlorsulfuron
on
cherry
trees
is
characteristic
of
other
plant
species,
drift
may
severely
reduce
both
the
crop
yields
and
fruit
development
on
native
plants,
an
important
component
of
the
habitat
and
food
web
for
wildlife.
Reproductive
effects
from
chlorsulfuron
exposure
are
difficult
to
recognize
in
the
field
and
virtually
impossible
to
associate
with
chlorsulfuron
because
the
amounts
of
material
required
to
induce
yield
reduction
are
below
the
detection
level
of
conventional
chemical
analysis.

Non­
target
Plant
Incident
Reports
There
are
three
non­
target
plant
incidents
attributed
to
offsite
drift
of
chlorsulfuron
(
Glean
®
)
in
the
EPA's
EIIS
incident
database.
One
incident
occurred
in
the
spring
of
1990,
near
Benton
City
Washington,
orchard
growers
alleged
that
herbicides
applied
to
wheat
fields
in
Horse
Heaven
Hills
drifted
onto
orchards
in
Badger
Canyon
and
damaged
cherry,
apple,
plum,
and
apricot
crops.
Growers
contended
that
sulfonylurea
herbicides
were
most
likely
responsible
because
damage
of
this
magnitude
never
occurred
prior
to
the
use
of
sulfonylurea
herbicides
on
Horse
Heaven
Hills
(
see
Section
3.7.3).

Endangered
Plant
Species
Screening
level
(
Tier
1)
deterministic
risk
quotients
(
RQs)
for
direct
effects
to
endangered
plants
exceed
the
endangered
species
level
of
concern
(
LOC)
by
several
orders
of
magnitude.
For
aquatic
plants
RQs
for
endangered
species
range
from
18
to
31.
For
endangered
plants
in
wetlands
RQs
range
from
1200
to
5056.
RQs
for
endangered
terrestrial
plants
range
from
3507
for
ground
applications
to
wheat
to
68,488
from
spray
drift
resulting
from
aerial
applications
to
rangeland
and
pastures.

In
order
to
determine
the
potential
risk
of
chlorsulfuron
uses
to
endangered/
threatened
plants,
further
refinements
are
needed
in
the
risk
assessment.
Possible
areas
of
refinement
could
include:
investigating
the
extent
of
overlap
between
species
habitat
relative
to
chlorsulfuron
use
areas
and
refining
site­
specific
exposure
scenarios
for
runoff
and
spray
drift.
Drinking
Water
Assessment
for
Human
Health
Page
vii
of
90
Concentrations
of
parent
chlorsulfuron
in
drinking
water
sources
were
estimated
using
PRZM/
EXAMS
for
surface
sources.
Four
standard
EFED
agricultural
scenarios
(
PA
turf,
FL
turf,
ND
wheat,
TX
wheat)
were
selected
to
simulate
a
broad
range
of
chlorsulfuron
uses.
The
estimated
concentrations
include
a
reduction
by
the
percent
crop
area
(
PCA)
factor.
The
Florida
turf
scenario
gave
the
highest
concentrations.
Ground
water
concentrations
were
estimated
with
the
SciGrow
model.
Using
standard
operating
guidance
for
SciGrow
inputs,
the
estimated
the
groundwater
concentration
was
1.6
ppb.
The
1­
in­
10
year
concentrations
are
provided
below.

Drinking
Water
Estimated
Environmental
Concentrations
for
Chlorsulfuron
Acute
Concentration
(
upper
1­
in­
10
year
peak
concentration)
Chronic
Concentration
(
upper
1­
in­
10
year
annual
mean
concentration)

Surface
Water
1.9
µ
g/
L
0.96
µ
g/
L
Groundwater
1.6
µ
g/
L
1.6
µ
g/
L
Page
1
of
90
1.
PROBLEM
FORMULATION
1.1
Conceptual
Model
In
agricultural
ecosystems
there
is
a
patchwork
of
row
crops
intermixed
with
pasture
and
natural
plant
communities.
Chlorsulfuron
poses
a
potential
threat
to
vegetation
growing
on
adjacent
land
if
the
herbicide
is
applied
to
crop
land
and
inadvertently
drifts
and/
or
runs
off
into
non­
target
areas.
Adverse
consequences
of
such
an
event
will
vary
depending
on
the
extent
of
exposure
(
aerial
vs
ground
application),
plant
species
involved,
habitat
(
aquatic
vs
terrestrial),
plant
size,
and
stage
of
development
of
the
plant.
The
response
may
range
from
plant
death
to
no
apparent
alteration
of
plant
growth
and
development,
depending
on
different
combinations
of
these
variables.

It
is
often
difficult
to
distinguish
between
herbicide
damage
and
plant
damage
caused
by
insects,
pathogens,
frost,
and
nutrient
deficiency.
Positive
proof
of
drift
or
runoff
damage
on
many
occasions
requires
chemical
identification
of
the
suspected
herbicide
on
the
plants
and/
or
the
soil
at
the
nontarget
site.
Complaints
have
arisen
in
numerous
parts
of
the
country
that
herbicides
such
as
the
sulfonylureas
which
are
used
at
1/
20th
the
application
rate
of
older
herbicides
cause
plant
damage
at
chemical
concentrations
below
the
level
of
analytical
detection
(
Fletcher
1991).

1.2
Identification
and
Mechanism
of
Action
Chlorsulfuron
is
a
broad
spectrum
herbicide,
structurally
classified
as
a
sulfonylurea.
Its
mode
of
action
is
the
inhibition
of
amino
acid
synthesis
in
plants
through
inhibition
of
acetolactate
synthase
(
ALS).
Chlorsulfuron's
herbicidal
effect
results
from
its
inhibition
of
an
enzyme
involved
in
amino
acid
biosynthesis.
It
may
be
absorbed
either
through
the
roots
or
the
foliage
and
is
mobile
within
the
plant
and
binds
to
the
acetolactate
synthase
enzyme.
Inhibiting
this
process
adversely
affects
plant
growth
and
reproduction.
This
enzyme
pathway
does
not
exist
in
animals
making
the
herbicide
far
less
toxic
to
animals
than
plants.

Soil
moisture
increases
the
phytotoxicity
of
chlorsulfuron
by
increasing
availability
and
absorption
by
the
roots.
Although
chlorsulfuron
is
herbicidal
when
absorbed
by
roots,
herbicide
which
contacts
foliage
is
also
phytotoxic.
Foliar
absorption
may
increase
when
chlorsulfuron
is
tank
mixed
with
an
oil
or
surfactant.
Chlorsulfuron
may
be
applied
either
pre­
or
post
emergence.
Phytotoxicity
data
shows
that
chlorsulfuron
affects
plants
in
both
seedling
emergence
and
the
vegetative
vigor
tests
at
low
levels.
Chlorsulfuron
tolerant
plants,
such
as
grains,
resist
herbicidal
effects
by
metabolizing
the
herbicide
before
it
causes
toxicity
(
Weed
Science
Society
1989).
Chlorsulfuron
exposure
may
cause
visible
symptoms
in
days
or
weeks
or
delayed
effects
on
reproduction
(
fruit
and
seed
production)
may
occur
weeks
or
months
after
exposure.

Plants
that
have
absorbed
sufficient
chlorsulfuron
on
their
foliage,
in
the
short
term,
may
show
initial
symptoms
of
spotting,
and
leaf
puckering
or
twisting
(
Felsot
et
al
1996).
Exposed
plants
also
may
show
chlorosis
and
discolored
veins.
Chlorsulfuron
symptoms
may
become
more
pronounced
and
lead
to
plant
death
or
the
plant
may
outgrow
the
symptoms
in
1
to
2
months
depending
on
the
sensitivity
of
the
plant
and
the
magnitude
of
the
exposure.
Developmental/
reproductive
effects
of
Page
2
of
90
chlorsulfuron
exposure
may
not
be
apparent
for
three
or
more
months
after
exposure.
Reduced
seed
and
fruit
development
resulting
from
chlorsulfuron
exposure
has
been
documented
in
canola,
smartweed,
soybean,
and
sunflower
(
Fletcher
et
al
1996).
Because
reproductive
effects
may
occur
in
the
absence
of
other
more
immediate
symptoms
of
herbicide
exposure,
it
is
expected
to
be
difficult
to
recognize
delayed
chlorsulfuron
toxicity
in
the
field.

1.3
Use
Characterization
and
Formulations
Chlorsulfuron­
containing
products
were
first
registered
in
the
United
States
in
the
early
1980s.
There
are
six
products
currently
registered
for
use
in
the
U.
S.
including:
TELAR
DF
®
,
GLEAN
FC
®
,
FINESSE
®
,
Chlorulfuron
Technical
®
,
LANDMARK
MP
®
,
LANDMARK
II
MP
®
,
and
CORSAIR
®
.
Over
80%
of
chlorsulfuron
use
is
on
cereal
grains
(
wheat,
oats
and
barley)
to
control
a
wide
variety
of
weed
pests.
Over
5
million
acres
are
treated
annually.
Most
of
the
acreage
is
treated
with
0.01
lbs
ai/
acre
or
less.
The
vast
majority
of
chlorsulfuron
is
applied
to
winter
wheat.
The
remaining
use
is
primarily
spring
wheat,
and
oats.
Registered
use
sites
with
little
or
no
usage
include
lawn
and
ornamental
turf.
Most
chlorsulfuron
usage
is
in
Oklahoma,
Texas,
Washington,
Kansas,
Montana,
and
California.

For
cereal
grains,
the
greatest
chlorsulfuron
usage
is
in
Kansas,
followed
by
Oklahoma,
Montana,
Washington,
Texas,
Nebraska,
North
Dakota,
and
California.
For
the
non­
crop
market,
the
greatest
usage
is
in
Iowa,
followed
by
Washington,
Oregon,
Colorado,
Idaho,
Minnesota,
Mississippi,
and
Nebraska.
Chlorsulfuron
is
also
registered
for
use
on
pasture
and
rangeland.
The
non­
crop
land
and
industrial
turf
sites
includes
use
on
roadsides,
railroads,
industrial
sites,
rights
of
way,
airports,
fence
rows,
and
lumberyards
for
control
of
noxious
weeds.

1.4
Rate
and
Method
of
Application
Chlorsulfuron
is
used
predominately
on
grain
crops
such
as
barley,
wheat,
and
oats.
According
to
the
USGS
and
USDA,
this
use
accounts
for
more
than
98%
of
agricultural
chlorsulfuron
usage
(
http://
ca.
water.
usgs.
gov/
pnsp/
use92/
chlrsulf.
html).
Chlorsulfuron
may
be
broadcast
applied
by
air
or
ground
equipment
to
small
grains
at
application
rates
that
range
from
0.0078
to
0.023
lbs
ai/
acre.
Acreage
may
be
treated
once
per
crop
cycle
to
once
every
36
months.

Chlorsulfuron
may
be
broadcast
applied
by
air
or
ground
equipment
to
fallow,
pasture,
and
rangeland
at
rates
that
range
from
0.0078
to
0.0625
lbs
ai/
acre.
Other
non­
crop
uses
(
unimproved
turf,
noncrop
sod
farms,
ornamentals)
may
only
be
applied
by
ground
equipment.
Application
rates
range
from
0.012
to
0.25
lbs
ai/
acre.
Acreage
may
be
treated
twice
per
year
for
some
uses;
for
other
uses
labels
do
not
specify
a
maximum
number
of
applications
per
year.
Table
1
summarizes
application
methods
and
maximum
rates
for
chlorsulfuron.
Page
3
of
90
Table
1.
Chlorsulfuron
Use
Information
Crop
Application
Method
Application
Rate
(
lbs
ai/
acre)
Maximum
number
of
applications
per
season
Maximum
seasonal/
yearly
application
rate
Barley
Post­
emergent
Broadcast
aerial
or
ground
0.0078
­
0.016
Ranges
from
once
per
crop
season
to
once
every
36
months
(
Finesse
label
does
not
specify)
0.016
lbs
ai/
acre
(
Finesse
label
does
not
specify)

Oats
pre­
emergent
Broadcast
aerial
or
ground
Up
to
0.023
Range
of
once
per
crop
season
to
every
36
months
0.023
lbs
ai/
acre
Oats
Post­
emergent
Broadcast
aerial
or
ground
0.0078
­
0.016
Range
of
once
per
crop
season
to
once
every
36
months
0.016
lbs
ai/
acre
Wheat
Pre­
emergent
Broadcast
aerial
or
ground
0.0195
­
0.023
Range
of
once
per
crop
season
to
once
every
36
months
(
Finesse
label
does
not
specify)
0.023
lbs
ai/
acre
(
Finesse
label
does
not
specify)

Wheat
Post­
emergent
Broadcast
aerial
or
ground
0.0078
­
0.016
Range
of
once
per
crop
season
to
once
every
36
months
(
Finesse
label
does
not
specify)
0.016
lbs
ai/
acre
(
Finesse
label
does
not
specify)

Pastures
and
rangeland
Broadcast
aerial
or
ground
0.012
­
0.0625
Label
does
not
specify
0.0625
lbs
ai
per
acre
per
12
month
period
Fallow
Broadcast
aerial
or
ground
0.0078
­
0.016
Label
does
not
specify
Label
does
not
specify
Unimproved
turf
Broadcast
ground
only
0.012
Label
does
not
specify
0.023
lbs
ai/
acre/
year
Unimproved
industrial
turf
Broadcast
ground
only
0.012
­
0.0234
2
per
year
(
Telar
DF
label
does
not
specify)
0.0234
lbs
ai
per
acre
per
12­
month
period
Non­
crop
sites
Broadcast
ground
only
0.021
­
0.047
Label
does
not
specify
0.12
lbs
ai/
acre/
year
Non­
crop
(
industrial)
sites
Broadcast
ground
only
0.021
­
0.14
Label
does
not
specify
0.125
lbs
ai/
acre
(
Telar
DF
label
does
not
specify)

Non­
cropland
restoration
Broadcast
ground
only
0.021
­
0.031
Label
does
not
specify
0.125
lbs
ai/
acre/
year
Sod
farms
and
golf
courses
Handheld
or
boom
sprayer
0.047
­
0.25
2
per
year
(
60
day
interval)
0.50
lbs
ai/
acre/
year
Ornamentals/
fine
turf
Broadcast
ground
only
0.13
­
0.25
2
per
year
0.25
­
0.50
lbs
ai/
acre
per
year
1.5
Current
Label
Restrictions
Current
chlorsulfuron
labels
contain
a
number
of
restrictions
that
may
tend
to
mitigate
to
some
degree
the
potential
impacts
of
chlorsulfuron
on
non­
target
and
endangered
plant
species.
For
example,
statements
on
the
label
for
Finesse
®
(
EPA
Reg.
No.
352­
445)
indicate
that
"
Finesse
herbicide
is
recommended
for
use
on
land
primarily
dedicated
to
the
long­
term
production
of
wheat
and
barley".
This
recommendation
may
serve
to
decrease
the
likelihood
that
irrigation
water
contaminated
with
chlorsulfuron
will
be
inadvertently
applied
to
agricultural
crops
that
are
sensitive
to
chlorsulfuron.
Finesse
labels
provide
the
following
precaution:
"
Do
not
apply
to
irrigated
land
where
tailwater
will
Page
4
of
90
be
used
to
irrigate
other
cropland."
The
extent
to
which
this
statement
serves
to
decrease
chlorsulfuron
contamination
of
surface
water
used
for
irrigation
is
uncertain.

An
indication
of
the
persistence
of
chlorsulfuron
under
actual
field
conditions
is
provided
in
the
label
for
Finesse
®
,
in
the
table
on
rotation
intervals.
The
table
indicates
that
the
rotation
interval
for
noncereal
crops
in
non­
irrigated
land
ranges
from
11
months
for
field
corn
to
48
months
for
sorghum.
These
intervals
indicate
that
chlorsulfuron
may
persist
in
the
soil
at
levels
that
are
toxic
to
plants
for
extended
periods
of
time.
Additionally,
labels
for
Finesse
®
provide
the
following
precaution:
"
To
reduce
the
potential
for
movement
of
treated
soil
due
to
wind
erosion,
do
not
apply
to
powdery,
dry,
or
light
sandy
soil
until
they
have
been
stabilized
by
rainfall,
trashy
mulch,
reduced
tillage
or
other
cultural
practices.
Injury
to
adjacent
crops
may
result
when
treated
soil
is
blown
onto
land
used
to
produce
crops
other
than
cereal
grains."
The
extent
to
which
this
statement
serves
to
decrease
the
movement
of
chlorsulfuron
contaminated
soils
into
nearby
fields
in
which
non­
cereal
crops
are
grown
is
uncertain.

Several
labels
have
restrictions
based
on
soil
pH.
Primarily
these
restrictions
are
to
protect
replanted
crops
after
chlorsulfuron
application.
Several
labels
(
e.
g.,
Dupont
Glean
®
and
Finesse
®
)
prohibit
the
use
of
chlorsulfuron
on
soils
with
pH
greater
than
7.9
because
chlorsulfuron
is
quite
persistent
at
high
pH
and
re­
planting
may
suffer
the
effects
of
residual
chlorsulfuron.
In
certain
states
these
labels
require
a
field
bioassay
if
pH
is
above
6.5
to
determine
whether
planting
is
feasible.
Crop
rotation
intervals
are
pH
dependent
in
some
states.
Supplemental
labels
may
imply
that
the
maximum
pH
limitation
is
less
for
certain
state/
crop
conditions.
Some
labels
(
e.
g.,
Dupont
Telar
®
and
Landmark
MP
®
)
appear
not
to
restrict
the
use
chlorsulfuron
based
on
soil
pH,
but
instead
only
restrict
the
replanting
interval.
Other
labels
(
e.
g.,
Lesco
TFC
®
and
Riverdale
Corsair
®
)
specify
reduced
application
rates
on
soils
with
pH
above
7,
but
do
not
prohibit
use
at
any
specific
soil
pH.

Some
label
precautions
suggest
that
synergistic
effects
may
occur
if
chlorsulfuron
is
applied
to
fields
to
which
certain
other
insecticides
have
been
applied.
The
label
for
Finesse
®
states
that
"
Finesse
should
not
be
used
within
60
days
of
crop
emergence
if
an
organophosphate
insecticide
(
such
as
"
Di
Syston
®
"
)
was
used
as
an
in­
furrow
treatment,
or
crop
injury
may
result."
Presumably,
neither
of
these
two
pesticides
if
used
alone
will
cause
crop
injury
to
wheat
or
barley.
However,
the
Finesse
label
indicates
that
they
apparently
do
cause
crop
injury
when
used
together.
This
suggests
that
there
may
be
synergistic
effects
to
plants
when
chlorsulfuron
is
applied
to
fields
along
with
organophosphate
insecticides.
The
label
for
Finesse
®
also
indicates
that
"
Tank­
mix
applications
of
Finesse
®
plus
Assert
®
may
cause
temporary
crop
discoloration/
stunting
or
injury
when
heavy
rainfall
occurs
shortly
after
application."
Additionally,
the
label
restricts
the
use
of
Finesse
®
plus
Malathion
®
and
the
use
of
Finesse
®
plus
Lorsban
®
in
the
Northwest,
as
crop
injury
may
result.
The
Finesse
®
label
includes
the
following
statement
"
Do
not
apply
Finesse
during
the
boot
stage
or
early
heading
stage,
as
crop
injury
may
result."
This
statement
suggests
that
chlorsulfuron
may
adversely
effect
plant
reproduction.

Several
statements
have
been
placed
on
chlorsulfuron
labels
to
reduce
the
likelihood
of
spray
drift.
The
label
for
Finesse
®
provides
the
following
statement:
"
When
applying
Finesse
by
air
in
areas
near
sensitive
crops,
use
solid­
stream
nozzles
oriented
straight
back.
Adjust
swath
to
avoid
spray
drift
Page
5
of
90
damage
to
downwind
sensitive
crops
and/
or
use
ground
equipment
to
treat
border
edges
of
fields."
A
refined
analysis
of
effects
of
spray
drift
is
provided
in
this
assessment,
however,
the
extent
to
which
these
statements
reduce
risk
to
plants
from
spray
drift
cannot
be
determined
based
on
the
level
of
detail
provided.

1.6
Assessment
Endpoints
and
Analysis
Plan
Laboratory
toxicity
tests
indicate
that
chlorsulfuron
is
practically
nontoxic
to
terrestrial
and
aquatic
animals.
However,
results
of
toxicity
tests
for
non­
target
terrestrial
and
aquatic
plants
indicate
that
chlorsulfuron
is
acutely
toxic.
Very
little
data
exist
on
levels
that
cause
chronic
toxicity
to
plants.
Therefore,
the
screening
level
assessment
focuses
on
endpoints
related
to
acute
effects
to
plants.
For
terrestrial
plants,
endpoints
include
vegetative
vigor
and
seedling
emergence.
Effects
on
growth
is
the
endpoint
used
for
aquatic
plant
risk.
Chronic
(
reproductive)
endpoints
for
plants
were
not
used
in
the
assessment
because
current
plant
test
guidelines
include
only
acute
endpoints.
However,
results
of
field
studies
indicate
that
chlorsulfuron
may
adversely
affect
plant
reproduction
at
low
concentrations
(
Section
3.7).

In
this
screening­
level
assessment,
exposure
was
estimated
based
on
maximum
label
rates.
Acute
risk
quotients
for
terrestrial
and
endangered
plant
species
were
calculated
for
three
different
habitat
types
adjacent
to
application
sites:
aquatic
habitats,
wetlands,
and
terrestrial
areas.
PRZM/
EXAMS
modeling
was
utilized
to
evaluate
potential
exposure
to
aquatic
plants
(
Section
2.2).
For
non­
target
and
endangered
terrestrial
plant
spray
drift
exposure
values,
1
or
5%
of
the
application
rate
was
assumed,
depending
on
whether
the
application
method
was
aerial
or
with
ground
equipment.
When
runoff
was
included
in
the
RQ
calculations
for
semi­
aquatic/
wetland
exposures,
the
exposure
was
assumed
to
be
5%
of
the
application,
based
on
chlorsulfuron's
solubility.
Runoff
exposure
was
then
added
to
spray
drift
exposure.
For
the
pasture/
rangeland
use,
a
direct
application
scenario
was
not
assessed;
however,
exposure
would
be
expected
to
be
higher
than
that
estimated
to
result
from
spray
drift.

This
ecological
risk
assessment
focuses
on
the
small
grain,
turf,
rangeland,
and
pasture
use
sites
because
they
represent
the
use
sites
with
the
largest
amount
of
current
or
potential
chlorsulfuron
use.
However,
some
of
the
non­
crop
uses
have
higher
application
rates
than
the
crop
uses.
If
risk
quotients
were
to
be
calculated
for
the
chlorsulfuron
non­
crop
uses
with
the
higher
application
rates,
they
would
likely
result
in
higher
risk
estimates
than
were
calculated
for
the
crop
uses.
Several
of
the
chlorsulfuron
labels
do
not
specify
application
frequency.
This
risk
assessment
assumes
a
single
application
where
the
label
is
not
specific;
actual
exposure
may
be
substantially
higher.
Page
6
of
90
Figure
1.
Chemical
structure
of
chlorsulfuron.
2.0
ENVIRONMENTAL
FATE
CHARACTERIZATION
Chlorsulfuron
(
2­
chloro­
N­[[(
4­
methoxy­
6­
methyl­
1,3,5­
triazin­
2­
yl)
amino]
carbonyl]
benzenesulfonamide,
see
Figure
1)
is
persistent
and
highly
mobile
in
the
environment.
It
may
be
transported
by
runoff
or
spray
drift.
Degradation
by
hydrolysis
appears
to
be
the
most
significant
mechanism
for
degradation
of
chlorsulfuron,
but
is
only
significant
in
acidic
environments
(
23
day
half­
life
at
pH
=
5);
it
is
stable
to
hydrolysis
at
neutral
to
high
pH.
Degradation
half­
lives
in
soil
environments
were
quite
variable
and
ranged
from
14
to
320
days.
Page
7
of
90
2.1
Chlorsulfuron
Fate
Studies
2.1.1
Hydrolysis
Chlorsulfuron
degraded
with
a
half­
life
of
23
days
in
the
pH
5
solution,
but
was
stable
in
the
pH
7
and
9
solutions.
Hydrolysis
tests
(
MRID
421567­
01)
were
performed
in
buffered
solutions
at
pH
values
of
5,
7,
and
9
at
25o
C.
Buffered
solutions
were
made
from
Milli­
Q
water
and
acetate,
phosphate,
and
borate
buffers,
respectively.
Initial
chlorsulfuron
concentrations
were
5
mg/
L.
Chlorsulfuron
concentrations
were
measured
at
3,
7,
14,
21,
and
31
days.
Major
degradates
were
from
the
pH
5
test
were
chlorosulfonamide
(
33%
of
applied),
ring­
opened
chlorsulfuron
(
16%
of
applied),
o­
desmethylchlosulfuron
(
10%
of
applied),
and
lesser
amounts
of
triazine
and
dihydroxy
triazine.

2.1.2
Photodegradation
in
Water
Chlorsulfuron
does
not
readily
photodegrade
in
water.
Tests
were
conducted
at
pH
5,
7
and
9
at
temperature
of
25oC
over
31
days
(
MRID
421567­
02).

2.1.3
Soil
Photodegradation
Soil
photolysis
tests
(
MRID
421567­
03)
showed
that
chlorsulfuron
degraded
with
a
half­
life
of
65
days.
The
test
soil
was
a
Nora
silty
clay
(
20%
sand,
52%
silt,
29%
clay,
2%
organic
matter,
CEC
19.6
meq/
100
g,
pH
8).
Minor
degradates
were
observed
at
less
than
10%
of
the
applied
and
included:
dihydroxy
triazine,
triazine
amine,
triazine
urea,
and
o­
desmethyl
chlorsulfuron.

2.1.4
Aerobic
Soil
Metabolism
Soil
metabolism
tests
(
MRID
422142­
01)
conducted
at
25oC
showed
a
wide
range
in
variability
of
the
aerobic
soil
half
life
of
chlorsulfuron.
In
a
silt
loam
soil
(
21%
sand,
63%
silt,
17%
clay,
2.75%
organic
matter
and
a
of
pH
6.4),
chlorsulfuron
had
a
half­
life
of
14
days.
In
another
soil
(
24%
sand,
68%
silt,
8%
clay,
2.6%
loam,
pH
9,
CEC
15.03
meq/
100g),
chlorsulfuron
had
a
half­
life
of
11
months.
In
older
submitted
studies
(
MRID
0113­
0013
and
0113­
0024),
chlorsulfuron
half­
lives
were
1
to
2
months.
In
more
recent
publications,
Andersen
et
al.
(
2001)
reported
chlorsulfuron
half­
lives
of
50
days
for
soil
taken
from
30
to
35
cm
below
surface,
160
days
for
soil
taken
40
to
45
cm
below
surface
and
230
days
for
soil
taken
at
70­
75
cm
below
surface.
One
reason
for
the
decrease
in
degradation
rates
is
possibly
due
to
a
decrease
in
microbial
activity
with
depth.
Andersen
et
al.
(
2001)
did
not
report
near­
surface
soil
data
due
to
interference
problems.
Major
degradates
were
2­
chlorobenzenesulfonamide
(
30­
35%),
2­
amino­
4­
methoxy­
6­
methyl­
1,3,5­
triazine,
and
2­
chloro­
N­
[[(
4­
hydroxy­
6­
methyl­
1,3,5­
triazin­
2­
yl)
­
amino]
carbonyl]
benzenesulfonamide
(
15%).
In
all
of
the
studies,
it
is
not
clear
how
much
degradation
occurred
by
microbial
metabolism
or
by
hydrolysis.
Page
8
of
90
2.1.5
Anaerobic
Aquatic
Metabolism
Chlorsulfuron
is
relatively
stable
under
conditions
of
anaerobic
metabolism.
Controls
degraded
faster
than
test
systems.
Hydrolysis
was
likely
the
dominant
mechanism
in
the
system
(
MRID
421467­
04).
In
recent
literature,
Berger
and
Wolfe
(
1996)
found
an
anaerobic
sediment
half
life
of
89
days
and
301
days
for
unsterile
and
sterile
sediment
respectively;
however,
for
another
sediment
system
it
was
182
days
and
only
101
days
for
the
sterile
system.
These
counterintuitive
results
were
attributed
to
increased
hydrolysis
due
to
lowing
of
pH
during
heat
sterilization.

2.1.6
Bioaccumulation
Preliminary
fish
bioaccumulation
studies
(
MRID
422142­
04)
showed
channel
catfish
accumulation
factors
of
1.5X
in
edible
tissue,
12X
in
viscera,
and
7X
in
liver.
Residues
declined
by
90­
95%
during
the
depuration
phase.
In
preliminary
bluegill
sunfish
studies
the
bioaccumulation
was
4X
in
the
viscera
and
6X
in
the
liver
with
a
residue
decline
of
70­
90
%
in
the
depuration
phase.
Chlorsulfuron
has
a
relatively
low
K
ow
of
2.13
at
pH
5,
0.10
at
pH
7,
and
0.04
at
pH
9
at
25oC.
This
information
is
sufficient
to
indicate
that
chlorsulfuron
has
a
low
potential
to
bioaccumulate.

2.1.7
Field
Dissipation
Although
guideline
field
studies
were
not
submitted,
older
lysimeter
studies
were
available
and
provide
sufficient
information
to
evaluate
chlorsulfuron
field
dissipation
for
this
assessment.
In
the
field
lysimeter
studies
(
MRID
422142­
02),
estimated
half­
life
ranged
from
20
days
to
several
months.
MRID
422142­
02
is
a
compilation
of
several
studies
identified
by
the
registrant­
assigned
report
numbers
in
parenthesis
that
follow.
Lysimeter
studies
in
Delaware,
North
Dakota,
and
Nebraska
(
Report
No.
63­
82)
were
conducted
on
both
an
alkaline
and
an
acidic
soil.
For
the
acidic
soils
the
dissipation
half­
life
ranged
from
1
to
2
months,
and
for
the
alkaline
soils,
dissipation
half­
lives
were
reported
to
be
2
­
4
months.
Another
study
(
Report
No.
AMR
307­
84)
was
carried
out
in
the
Fall
in
Ohio,
Idaho,
North
Dakota,
and
in
the
Spring
in
Alberta,
Manitoba
and
Saskatchewan,
Canada.
Dissipation
half­
lives
were
reported
to
be
1
to
3
months
for
the
Spring
studies
and
5
to
11
months
for
the
Fall
studies.
Leaching
of
chlorsulfuron
was
apparent.
The
time
for
detectable
levels
of
chlorsulfuron
to
reach
22
­
35
cm
ranged
from
1
to
40
months.
In
another
lysimeter
study
(
Report
No.
AMR
1417­
89)
leaching
was
also
apparent
down
to
the
18­
24
inch
range.
The
reported
dissipation
half­
life
was
20
days.
In
all
the
studies,
only
minor
amounts
(<
10%)
of
two
degradates
(
2­
chlorobenzenesulfonamide
and
2­
amino­
4­
methoxy­
6­
methyl­
1,2,3,5­
triazine)
were
observed.

2.1.8
Sorption
A
summary
of
batch
sorption
tests
is
given
in
Table
2.
Batch
studies
(
MRID
421567­
05)
were
conducted
on
four
soils
with
an
equilibration
time
of
24
hours
at
25o
C.
From
the
sorption
parameters
chlorsulfuron
can
be
considered
mobile
(
Table
2).
It
is
expected
(
as
with
many
chemicals
that
become
increasingly
anionic
with
increasing
pH)
that
the
mobility
of
chlorsulfuron
will
increase
with
increasing
pH.
Page
9
of
90
Table
2.
Summary
of
Submitted
Sorption
Studies
Registrant's
Name
for
Soil
texture
%
sand
%
silt
%
clay
%
om
CEC
meq/
100g
soil
pH
K
f
mg/
l/(
mg/
kg)
1/
n
1/
n
Koc
a
(
ml/
g)

Madera
loam
48
35
17
0.8
19.6
8
0.28
0.9
60
Woodstone
sandy
loam
60
33
7
1.1
5.3
6.6
0.09
0.85
14
Keyport
silt
loam
20
39
21
1.9
6.4
5.7
0.38
0.88
34
Flanagan
silt
loam
2
81
17
4.3
21.1
5.4
0.91
0.91
36
a
K
oc
is
based
on
the
sorption
coefficient
at
1
mg/
L.

2.2
Water
Resource
Assessment
Due
to
its
mobility
and
persistence,
chlorsulfuron
may
contaminate
surface
and
groundwater.
Fate
studies
show
that
chlorsulfuron
is
mobile,
and
that
mobility
should
increase
as
the
environmental
pH
increases
(
chlorsulfuron
becomes
more
anionic
as
pH
increases,
see
for
example
the
variation
in
Kow
with
pH
in
the
bioaccumulation
section).
Chlorsulfuron
is
also
persistent,
and
its
persistence
should
also
increase
with
increasing
pH.

Few
monitoring
data
are
available
on
chlorsulfuron.
Due
to
its
very
low
application
rate
and
expected
low
concentrations
in
the
environment
it
is
not
often
included
as
a
analyte
in
monitoring
programs.
To
obtain
information
about
the
occurrence
of
sulfonylurea
(
SU),
sulfonamide
(
SA),
and
imidazolinone
(
IMI)
herbicides
in
the
Midwestern
United
States,
the
USGS
collected
212
water
samples
from
75
surface
water
sites
(
177
samples
taken)
and
25
ground­
water
sites
(
29
samples
taken)
in
1998
(
Battaglin
et
al.,
2000).
Samples
were
collected
from
streams,
large
rivers,
reservoir
outflows,
and
wells.
All
reconnaissance
samples
were
analyzed
for
16
different
herbicides.
The
75
surface
water
sites
were
located
in
the
Upper
Mississippi,
Missouri,
and
Ohio
River
basins.
Twenty
ground­
water
samples
were
collected
from
a
network
of
municipal
wells
in
Iowa.
The
depths
of
the
wells
ranged
from
6
to
83
m.
with
most
wells
less
than
30
m.
Samples
were
also
collected
from
five
observation
wells
in
Lower
Illinois;
these
wells
were
less
than
8
m
deep.

Of
the
130
samples
taken
from
Midwestern
rivers
and
streams,
only
one
sample
contained
chlorsulfuron
(
0.013

g/
L)
above
the
method
reporting
limit
of
0.01

g/
L.
The
USGS
scientists
reported
no
detections
of
chlorsulfuron
in
the
25
ground­
water
samples.
It
is
unclear
to
what
extent
the
location
of
sampling
sites
overlapped
with
areas
of
chlorsulfuron
usage.
Because
of
limitations
in
the
monitoring
data,
estimated
environmental
concentrations
in
this
assessment
were
calculated
using
the
models
PRZM/
EXAMS
and
SciGrow.

2.2.1
Ambient
Surface
Water
(
Farm
Pond)

Surface
water
concentrations
resulting
from
chlorsulfuron
application
to
wheat
and
turf
were
estimated
with
PRZM
(
version
3.12
beta)
coupled
to
EXAMS
(
version
2.98.04).
Four
scenarios
were
simulated
 
one
for
North
Dakota
wheat,
one
for
Texas
wheat,
one
for
Pennsylvania
turf,
and
Page
10
of
90
one
for
Florida
turf.
Application
timing
was
estimated
from
the
product
labels,
and
a
range
of
application
dates
were
used.
A
summary
of
chemical
properties
used
as
PRZM/
EXAMS
inputs
is
given
in
Table
3,
and
copies
of
input
files
are
in
Appendix
1.
Because
of
its
low
degradation
rate,
chlorsulfuron
concentrations
continually
increased
over
the
simulation
period
and
chronic
and
peak
concentrations
are
nearly
the
same
for
all
scenarios
tested.
Table
4
presents
the
peak
and
average
concentrations
for
the
simulated
farm
pond.
Note
that
the
standard
EFED
pond
is
confined
such
that
flushing
by
external
flows
does
not
occur,
and
therefore,
concentrations
may
accumulate
over
time
to
a
higher
degree
than
would
a
pond
with
flow
into
and
out
of
the
system.
The
date
chosen
for
the
application
had
a
small
(
absolute)
effect
on
the
output,
as
EEC
values
are
within
about
1
ppb
(
the
relative
difference
however
is
substantial
 
up
to
about
30%).
For
a
conservative
assessment,
the
highest
of
these
values
is
used.

Table
3.
Salient
Chemical
Properties
of
Chlorsulfuron
Used
for
PRZM/
EXAMS
Modeling
Parameter
Value
Notes
Molecular
Weight
357.8
Solubility
31800
mg/
l
Vapor
Pressure
4.6
e­
6
torr
K
oc
36
ml/
g
MRID
421567­
05
(
mean
of
values
in
Table
2)

Aerobic
Soil
half
life
320
days
90
%
ci
of
submitted
studies
(
half
life
data
:
14,
330,
60
days)
MRID
422142­
01
Aerobic
aquatic
half­
life
stable
MRID
421467­
04
Photodegradation
stable
MRID
421567­
052;
MRID
421567­
03
Anaerobic
metabolism
stable
assumption
Hydrolysis
stable
MRID
421567­
01
(
scenarios
are
performed
at
pH
=
7)
Page
11
of
90
Table
4.
Summary
of
Ecological
Concentrations
Modeled
with
PRZM/
EXAMS.
Chlorsulfuron
applied
once
per
season
at
maximum
labeled
rate.
All
values
in
ppb.

scenario
formulation
and
application
Date
Applied
peak
96
hr
21­
day
60­
day
90­
day
year
ND
wheat
Glean
0.023
lb/
acre
aerial
application
1­
Apr
4.2
4.2
4.2
4.2
4.2
4.2
1­
May
4.1
4.1
4.1
4.1
4.1
4.1
TX
wheat
Glean
0.023
lb/
acre
aerial
application
1­
Aug
5.5
5.5
5.5
5.5
5.5
5.5
1­
Sep
5.8
5.8
5.8
5.8
5.8
5.7
15­
Sep
6.0
6.0
6.0
6.0
6.0
5.9
1­
Oct
6.3
6.3
6.3
6.3
6.3
6.3
PA
turf
Telar
0.0625
lb/
acre
aerial
application
15­
Mar
4.0
4.0
4.0
4.0
4.0
4.0
1­
Apr
5.0
5.0
5.0
5.0
5.0
5.0
15­
Apr
4.5
4.5
4.5
4.5
4.5
4.5
1­
May
5.9
5.9
5.9
5.9
5.9
5.8
15­
May
5.2
5.2
5.2
5.2
5.2
5.0
FL
turf
Telar
0.0625
lb/
acre
aerial
application
1­
Mar
6.8
6.8
6.8
6.8
6.8
6.8
1­
Apr
9.5
9.5
9.5
9.5
9.5
9.5
1­
May
7.5
7.5
7.5
7.5
7.5
7.4
2.3
Drinking
Water
Assessment
2.3.1
Surface
Water
Source
This
drinking
water
assessment
estimates
exposure
to
parent
chlorsulfuron
only.
If
metabolites
of
concern
are
identified
a
revised
assessment
will
be
prepared.
EFED
previously
conducted
a
Tier
1
human
drinking
water
assessment
which
can
be
found
in
Appendix
8.
The
tier
1
drinking
water
estimates
for
ground
and
surface
water
source
drinking
water
used
higher
application
rates,
which
bracket
all
label
rates
in
Table
1.
Although
HED
did
not
indicate
problems
with
the
concentrations
from
the
Tier
1
assessment,
EFED
performed
a
Tier
2
human
drinking
water
assessment
in
order
to
be
consistent
with
the
Tier
2
ecological
water
assessment
described
above.
Concentrations
of
chlorsulfuron
in
drinking
water
sources
for
the
Tier
2
assessment
were
estimated
with
PRZM/
EXAMS
for
surface
sources.
Four
standard
scenarios
were
investigated..
Because
the
scenarios
are
the
same
as
those
used
for
the
ecological
assessments,
the
application
date
chosen
was
the
date
that
gave
the
highest
exposure
values,
as
determined
from
the
ecological
assessment
PRZM/
EXAMS
runs.
The
final
drinking
water
estimated
concentrations
reported
in
Table
5
are
reduced
by
the
percent
crop
area
(
PCA)
factors
reported
in
the
table.
Page
12
of
90
Table
5.
Summary
of
estimated
screening
level
surface
water
drinking
water
concentrations.
Based
on
one
application
scenario
formulation
PCA
application
date
peak
(
upper
1­
in­
10
year
peak
concentration)
[
ppb]
chronic
(
upper
1­
in­
10
year
annual
mean
concentration)
[
ppb]

ND
wheat
Glean
0.023
lb/
acre
0.56
May
1
0.32
0.23
TX
wheat
Glean
0.023
lb/
acre
0.56
Sep
15
0.95
0.25
PA
turf
Telar
0.0625
lb/
acre
1.0
April
1
1.5
1.1
FL
turf
Telar
0.0625
lb/
acre
1.0
April
1
2.2
1.1
2.3.2
Ground
Water
Source
Groundwater
concentrations
were
estimated
with
SciGrow,
which
is
EFED's
standard
model
for
estimating
groundwater
concentrations
of
pesticides.
For
further
information
on
this
model
see
the
EFED
water
model
website
at
http://
www.
epa.
gov/
oppefed1/
models/
water/.
The
following
model
inputs
were
used:
application
rate
=
0.0625
lb/
acre,
one
application
per
year,
half­
life
=
320
days,
and
K
oc
=
36.
With
these
inputs,
SciGrow
estimates
the
groundwater
concentration
to
be
1.6
ppb.

2.3.3
Drinking
Water
Estimated
Concentrations
The
surface
water
EECs
in
Table
6
were
based
on
a
PRZM/
EXAMS
simulation
using
EFED's
standard
Index
Reservoir.
The
Pennsylvania
turf
scenario
was
found
to
provide
the
highest
EECs
among
the
scenarios
tested.
For
groundwater,
the
SciGrow­
derived
model
estimated
concentration
of
1.6
µ
g/
L
was
derived
from
the
turf
scenario
(
see
previous
section).
Appendix
8
provides
additional
details
on
the
Tier
1
drinking
water
assessment
for
chlorsulfuron.

Table
6.
Drinking
Water
Estimated
Environmental
Concentrations
for
Chlorsulfuron.

Acute
Concentration
Chronic
Concentration
Surface
Water
2.2
µ
g/
L
1.1
µ
g/
L
Groundwater
1.6
µ
g/
L
1.6
µ
g/
L
Page
13
of
90
3.
ECOLOGICAL
EFFECTS
CHARACTERIZATION
This
screening
level
ecological
risk
assessment
was
performed
to
evaluate
the
potential
impact
to
nontarget
mammals,
birds,
fish,
and
aquatic
invertebrates
resulting
from
the
registered
uses
of
chlorsulfuron.
Based
on
available
toxicity
and
environmental
fate
data,
risks
to
mammals,
birds,
and
aquatic
organisms
are
not
expected
to
exceed
EFED's
Levels
of
Concern.
Thus
risks
to
birds
and
aquatic
animals
resulting
from
chlorsulfuron
use
are
expected
to
be
low.

3.1
Toxicological
Profile
for
Terrestrial
and
Aquatic
Animals
Table
7
provides
eco­
toxicity
values
for
terrestrial
and
aquatic
animals
that
were
used
to
calculate
acute
and
chronic
risk
quotients
for
non­
target
terrestrial
and
aquatic
animals.
Based
on
results
of
toxicity
testing,
chlorsulfuron
appears
to
be
practically
nontoxic
to
most
of
the
terrestrial
and
aquatic
animals
tested.

Adverse
reproductive
effects
were
observed
in
both
the
avian
(
northern
bobwhite)
and
mammalian
reproduction
studies,
although
at
test
concentrations
well
above
the
estimated
environmental
concentrations
(
EEC).
The
NOAEC
for
northern
bobwhite
was
determined
to
be
174
mg
ai/
kg
bw
diet
based
on
significant
reductions
in
female
body
weight,
14
day
old
survivors/
normal
hatchlings,
viable
embryos/
eggs
set,
and
14
day
hatchling
survival/
eggs
set
at
the
highest
treatment
level
when
compared
to
the
control.
Page
14
of
90
Table
7.
Chlorsulfuron
Toxicity
Tests
Used
to
Calculate
RQs
For
Terrestrial
and
Aquatic
Animals
.

Study
Type
(%
Active
Ingredient)
Species
Toxicity
Value
(
ai)
Toxicity
Category
MRID/
Acc.#
Author
(
Year)
Study
Classification
Dietary
LC
50
(
91%)
Mallard
duck
(
Anus
platyrhynchos)
LC
50>
5,000
ppm
Practically
nontoxic
099462
(
1979)
Core
Avian
Reproduction
(
97.5%)
Northern
bobwhite
(
Colinus
virginianus)
NOAE
=
174
ppm
LOEAL=
961
ppm
Not
applicable
42634001
Beavers,
J.
B.
et
al.
(
1992)
Core
Rat
two
generation
reproduction
Laboratory
rat
NOAEL
=
35
mg/
kg/
day
Not
applicable
40089316
Not
Applicable
Rat
acute
oral
Laboratory
rat
LD
50
=
5.5
g/
kg
Not
applicable
00031406
Not
Applicable
Acute
LC
50
(
91%)
Rainbow
trout
LC
50
>
250
ppm
Practically
nontoxic
099462
Core
Acute
LC
50
(
Technical)
Daphnia
magna
LC
50
>
370
ppm
Practically
nontoxic
099462
Core
Early
life­
stage
(
97.6%)
Rainbow
trout
NOAEC
=
32
mg/
l
Not
applicable
419764­
05
Pierson,
K.
B.
(
1991)
Core
Life­
cycle
(
95.4%)
Daphnia
magna
NOAEC
=
20
mg/
l
Not
applicable
419764­
08
Hutton,
D.
G.
(
1989)
Supplemental
1
Acute
LC
50
(
98.2%)
Mysid
(
Mysidopsis
bahia)
LC
50
=
89
mg/
l
slightly
toxic
419764­
02
Ward,
T.
J.
and
R.
L.
Boeri
(
1991)
Core
Acute
LC
50
(
98.2%)
Sheepshead
minnow
(
Cyprinodon
LC
50
>
980
mg/
l
practically
nontoxic
419764­
01
Ward,
T.
J.
and
R.
L.
Core
1/
This
study
is
scientifically
sound.
However,
it
does
not
fulfill
test
guideline
requirements.
It
is
repairable
if
additional
information
on
the
solvent
control
and
dilution
water
is
submitted.

A
summary
of
guideline
ecological
toxicity
studies
is
provided
in
Appendix
2.
Page
15
of
90
3.2
Risk
Quotients
for
Terrestrial
and
Aquatic
Animals
Table
8
provides
risk
quotient
values
for
terrestrial
and
aquatic
animals.

Table
8.
Chlorsulfuron
Risk
Quotients
for
Terrestrial
and
Aquatic
Animals.

Species
Toxicity
EEC
range
Risk
Quotients
acute
/
chronic
Birds
Acute
LC
50
>
5,000
ppm
Chronic
NOAEL
=
174
mg/
kg/
day
1.9
­
15
ppm
<
0.01
/
<
0.01
Mammals
Acute
LD
50
=
5,500
ppm
Chronic
NOAEC
=
35
mg/
kg/
day
1.9
­
15
ppm
<
0.01
/
<
0.01
Freshwater
fish
Acute
LC
50
=
>
50
ppm
Chronic
NOAEC
=
32
ppm
0.003
­
0.0096
ppm
<
0.01
/
<
0.01
Freshwater
invertebrate
Acute
LC
50
=
>
370
ppm
Chronic
NOAEC
=
20
ppm
0.003
­
0.0096
ppm
<
0.01
/
<
0.01
Marine
fish
Acute
LC
50
=
>
950
ppm
Chronic
NOAEC
=
N/
A
0.003
­
0.0096
ppm
<
0.01
/
N/
A
Marine
invertebrate
Acute
LC
50
=
89
ppm
Chronic
NOAEC
=
N/
A
0.003
­
0.0096
ppm
<
0.01
/
N/
A
Honey
bee
Acute
LD
50
>
25

g/
bee
N/
A
N/
A
3.2.1
Birds
and
Mammals
Acute
and
chronic
risk
quotients
do
not
exceed
Levels
of
Concern
(
LOC)
for
birds
and
mammals.
With
acute
toxicity
values
(
LC
50)
greater
than
5,000
ppm
and
relatively
low
EECs,
based
on
240
ppm
per
lb
ai
applied
(
Appendix
3)
chlorsulfuron
is
not
expected
to
pose
an
acute
risk
to
avian
species.
The
NOAEC
for
avian
reproduction
(
174
mg/
kg/
day)
is
more
than
an
order
of
magnitude
above
the
highest
EEC
(
15
ppm).
Because
of
low
acute
and
chronic
toxicity
to
laboratory
rats,
risk
quotients
do
not
exceed
the
LOCs
for
mammals.
Therefore,
chronic
risks
to
birds
and
mammals
are
not
expected
to
exceed
the
Levels
of
Concern.

3.2.2
Freshwater
and
Marine/
estuarine
Fish
and
Invertebrates
Acute
and
chronic
risk
quotients
do
not
exceed
the
LOC
for
freshwater
or
marine/
estuarine
fish
and
invertebrates.
With
acute
toxicity
values
(
LC
50)
greater
than
50
ppm
and
EECs
less
than
0.010
ppm,
chlorsulfuron
is
not
expected
to
pose
an
acute
risk
to
aquatic
animal
species.
Chronic
toxicity
tests
provide
NOAECs
that
are
greater
than
or
equal
to
20
ppm.
Therefore,
chlorsulfuron
is
expected
to
present
low
acute
or
chronic
risks
to
freshwater
and
marine/
estuarine
fish
and
invertebrates.
Page
16
of
90
3.3
Risk
Characterization
for
Terrestrial
and
Aquatic
Wildlife
Toxicity
tests
and
estimated
environmental
concentrations
indicate
those
chlorsulfuron
risks
resulting
from
direct
exposure
to
terrestrial
and
aquatic
animals
are
expected
to
be
low.
However,
the
potential
exists
for
indirect
impacts
because
animals
ultimately
depend
on
plants
and
plant
communities
for
survival.

3.4
Plant
Effects
Assessment
A
screening
level
risk
assessment
for
terrestrial
and
aquatic
plants
is
provided
below.
Laboratory
toxicity
values
for
plants
are
compared
with
estimated
environmental
concentrations
to
give
deterministic
risk
quotients.

3.4.1
Toxicological
Profile
for
Terrestrial
and
Aquatic
Plants
The
standard
toxicity
level
EFED
uses
for
calculating
risk
quotients
for
non­
endangered
terrestrial
plants
is
the
EC
25.
For
endangered
plants,
the
EC
05
or
the
no
observable
adverse
effect
level
(
NOAEL)
is
used.
The
EC
x
effect
level
represents
an
X%
effect
to
a
group
of
plants.
The
dose
required
to
cause
a
25%
reduction
in
the
average
shoot
height
of
a
group
of
plants
is
an
example
of
an
EC
25
toxicity
level.
Reduction
in
the
dry
weight
of
the
plant
can
also
be
used
in
calculating
the
EC
x.
Visual
effects,
such
as
spotting
or
chlorosis,
are
not
generally
assessed
because
of
difficulty
in
quantifying
the
magnitude
of
the
effect.

Table
9
provides
laboratory
toxicity
values
for
terrestrial
and
aquatic
plants.
Chlorsulfuron
is
toxic
to
nontarget
terrestrial
plants
with
EC
25
values
as
low
as
4
x
10
­
6
lbs
a.
i./
acre
and
an
EC
05
value
of
4.6
x
10
­
8
lbs
a.
i.
/
acre
(
vegetative
vigor).
Based
on
available
data,
the
slope
of
the
dose­
response
curve
for
chlorsulfuron
has
a
low
value;
toxicity
does
not
decrease
rapidly
with
decreasing
concentration.
As
a
result,
terrestrial
plant
treatment
concentrations
were
not
low
enough
in
the
seedling
emergence
and
vegetative
vigor
studies
to
determine
the
NOAEC
for
several
plant
species.
More
detailed
summaries
are
provided
in
Appendices
4
and
5.
Aquatic
plant
toxicity
ranged
from
practically
nontoxic
to
very
highly
toxic.
The
most
sensitive
aquatic
plant
was
Lemna
gibba
(
duckweed),
with
an
EC
50
of
0.00035
mg
ai/
L
and
a
NOAEC
of
0.00024
mg
ai/
L.

The
plants
used
in
phytotoxicity
tests
are
chosen
primarily
for
due
to
the
availability
of
validated
protocols
and
seed
sources.
Registrants
routinely
screen
potential
products
using
a
wide
variety
of
economically
important
plants
to
determine
if
phytotoxicity
concerns
exist.
The
Pesticide
Assessment
Guideline
Subdivision
J
(
EPA­
540/
9­
82­
020)
states
that
flexibility
is
allowed
in
choosing
species
in
order
to
maximize
use
of
"...
tests
that
are
normally
performed
by
the
developer/
registrant
during
screening
and
initial
field
testing...."
The
registrant
must
test
corn
and
soybeans
primarily
because
of
their
economic
importance
in
US
agricultural.
A
dicot
root
crop
must
also
be
tested
along
with
an
approximately
even
ratio
of
dicots
and
monocots.

Laboratory
toxicity
data
used
in
this
analysis
were
limited
to
effects
occurring
in
a
relatively
short
amount
of
time
after
a
single
exposure.
A
number
of
published
reports
suggest
that
chlorsulfuron,
Page
17
of
90
and
other
herbicides
with
the
same
mode
of
action,
may
result
in
delayed
effects
on
crop
yield
and
plant
reproduction
at
levels
lower
than
those
noted
to
cause
short­
term
visible
effects
(
for
a
review
see
Ferenc
2001).

Table
9.
Summary
of
Chlorsulfuron
Toxicity
Tests
for
Terrestrial
and
Aquatic
Plants.

Study
Type
(%
Active
Ingredient)
Species
Toxicity
Value
(
reported
application
rate)
MRID/
Acc.#
Author
(
Year)
Study
Classification
Seedling
emergence
and
Vegetative
vigor
(
98.2%
chlorsulfuron
purity)
All
chlorsulfuron
stock
and
test
solutions
were
prepared
in
pH
7
buffer
or
HPLC­
grade
acetone.
Valent
0.25%
X­
77
surfactant
was
used
in
some
test
solutions.
Seedling
emergence:
(
onion,
sugarbeet,
soybean,
sorghum,
pea,
rape,
cucumber,
corn,
and
tomato)

Vegetative
vigor:
(
Wheat,
onion,
sugarbeet,
soybean,
sorghum,
pea,
rape,
cucumber,
corn,
and
tomato)
Seedling
emerge:
(
sugarbeet,
shoot
height)
EC
25
=
3.06
x
10­
5
lbs
ai/
A
NOAEC
=
6.8
x
10­
6
lbs
ai/
A
Vegetative
Vigor:
(
onion,
shoot
weight)
EC
25
=
4.0
x
10­
6
lbs
ai/
A
EC
25
=
4.56
x
10
­
8
lbs
ai/
acre
425872­
01
and
422010­
01
McKelvey,
R.
A.,
and
H.
Kuratle
(
1992)
Supplemental
1
Aquatic
plant
growth
(
98.2%)
Selenastrum
capricornutum
EC
50
=
0.05
mg
ai/
L
NOAEC
=
0.0094
mg
ai/
L
421868­
01
Blasburg,
J.
et
al.
(
1991)
Supplemental
2
Aquatic
plant
growth
(
97.8%)
Skeletonema
costatum
NOAEC
=
126
mg
ai/
L
EC
50
>
126
mg
ai/
L
45832902
R.
L.
Boeri
et
al.
(
2001)
Core
Aquatic
plant
growth
(
97.8%)
Navicula
pelliculosa
NOAEC
=
126
mg
ai/
L
EC
50
>
126
mg
ai/
L
45832904
R.
L.
Boeri
et
al.
(
2001)
Core
Aquatic
plant
growth
(
97.8%)
Anabaena
flos­
aquae
NOAEC
=
0.236
mg
ai/
L
EC
50
=
0.609
mg
ai/
L
45832903
R.
L.
Boeri
et
al.
(
2001)
Core
Aquatic
plant
growth
(
97.8
%)
Lemna
gibba
NOAEC
=
0.00024
mg
ai/
L
EC
50
=
0.00035
mg
ai/
L
45832901
R.
L.
Boeri
et
al.
(
2001)
Supplemental
3
1/
This
study
is
scientifically
sound
but
does
not
fulfill
the
guideline
requirements
for
seedling
emergence
and
vegetative
vigor
studies
2/
This
study
could
be
upgraded
to
core
if
raw
data
are
submitted.

3/
This
study
was
conducted
under
static
conditions.

Because
of
deficiencies
in
the
plant
studies,
several
are
classified
as
supplemental
and
do
not
fulfill
data
requirements
for
plant
toxicity
testing.
However,
these
studies
were
determined
to
be
scientifically
sound
and
are
suitable
for
use
in
the
screening
level
risk
assessment
for
non­
target
and
endangered
plants.
Page
18
of
90
3.5
Risk
Quotients
for
Aquatic
and
Terrestrial
Plants
3.5.1
Aquatic
Plant
Assessment
Table
10
provides
screening
level
risk
quotients
for
non­
target
and
endangered/
threatened
aquatic
plants.
PRZM/
EXAMS
was
used
to
estimate
environmental
concentrations
(
EECs).
The
assumptions
used
in
this
modeling
are
provided
in
Section
2.2.
For
this
assessment
the
peak
EEC
was
used.
However,
as
Table
4
indicates,
the
EECs
after
a
year
are
essentially
the
same
as
the
peak
EECs.
The
duration
of
exposure
in
the
aquatic
plant
toxicity
testing
typically
ranges
from
5
to
14
days.
Therefore,
if
the
long­
term
EECs
were
used
instead
of
peak,
risk
quotients
would
remain
the
same.

The
Level
of
Concern
(
LOC)
for
non­
target
plants
is
1.0.
For
use
on
wheat,
non­
target
aquatic
plant
RQs
range
from
12
to
18
and
from
18
to
26
for
endangered
aquatic
plant
species.
For
use
on
turf
(
pasture/
rangeland
and
fallow),
RQs
range
from
17
to
27
for
non­
target
aquatic
plants
and
from
26
to
40
for
endangered
aquatic
plants.

Table
10.
Chlorsulfuron
Risk
Quotients
(
RQs)
for
Non­
target
and
Endangered/
Threatened
Aquatic
Plants
Using
a
E50
of
0.35

g/
L
and
a
NOAEC
of
0.24

g/
L
for
Lemna
gibba.
(
Single
Application).

Crop
(
state)
Application
rate
(
lbs
ai/
acre)
Peak
EEC
(
ppb)
(
PRZM/
EXAMS)
RQs
for
non­
target
aquatic
plants
1
RQs
for
endangered
aquatic
plants
2
Wheat
(
ND)
0.023
4.2
12
18
Wheat
(
TX)
0.023
6.3
18
26
Turf
(
PA)
0.0625
5.9
17
26
Turf
(
FL)
0.0625
9.5
27
40
1/
EEC/
E
50
2/
EEC/
NOAEC
Exposure
from
the
sod/
golf
course
and
nursery
uses
were
not
estimated
due
to
low
overall
usage;
however,
because
the
maximum
application
rates
for
those
uses
are
higher
than
for
the
uses
modeled,
the
LOCs
would
be
exceeded
for
these
uses
as
well.

3.5.2
Terrestrial
Plant
Assessment
The
screening
level
terrestrial
assessment
consists
of
the
following
four
scenarios:

1)
Off­
target
drift
and
runoff
of
chlorsulfuron
from
a
ten­
acre
application
site
to
an
adjacent
one
acre
semi­
aquatic
area
(
wetland)
using
seedling
emergence
toxicity
data
to
calculate
risk
quotients
(
Table
11),
based
on
a
single
application
of
chlorsulfuron.
Page
19
of
90
2)
Off­
target
drift
and
runoff
of
chlorsulfuron
from
a
one­
acre
application
site
to
an
adjacent
one
acre
terrestrial
area
using
seedling
emergence
toxicity
data
to
calculate
risk
quotients
(
Table
12),
based
on
a
single
application
of
chlorsulfuron.

3)
Off­
target
drift
and
no
runoff
of
chlorsulfuron
from
a
one­
acre
application
site
to
an
adjacent
one­
acre
terrestrial
area
using
vegetative
vigor
toxicity
data
to
calculate
risk
quotients
(
Table
13),
based
on
a
single
application
of
chlorsulfuron.

4)
Application
of
contaminated
irrigation
water
(
groundwater
or
surface
water
inadvertently
containing
chlorsulfuron)
using
the
vegetative
vigor
toxicity
data
to
calculate
risk
quotients
(
Table
14),
based
on
a
single
irrigation
event.

Table
11
provides
screening
level
RQs
for
semi­
aquatic
areas
(
wetlands)
resulting
from
off­
target
drift
(
concentrations
estimated
at
the
edge
of
the
treated
field)
and
runoff
of
chlorsulfuron
from
the
application
site
(
ten
acres
to
one
acre).
The
toxicity
endpoint
used
in
the
RQ
calculations
is
seedling
emergence.
A
ten­
acre
application
area
running
off
into
a
one­
acre
wetland
is
simulated
to
determine
the
estimated
environmental
concentrations
from
runoff
into
wetlands.

RQs
for
ground
application
of
chlorsulfuron
to
small
grains
(
wheat,
barley,
and
oats),
pasture
and
rangeland
range
from
267
to
1,042
for
non­
target
plants
and
from
1200
to
4,688
for
endangered/
threatened
plants.
RQs
for
aerial
application
to
small
grains,
pasture
and
rangeland
range
from
288
to
1123
for
non­
target
plants
and
from
1,294
to
5,056
for
endangered/
threatened
plants.
Therefore,
for
this
scenario,
(
which
assumes
10
acres
treated
to
one
acre
runoff),
risk
quotients
for
aerial
applications
are
approximately
8%
higher
than
the
risk
quotients
from
ground
applications.
Since
the
LOC
(
1.0)
is
exceeded
by
over
three
orders
of
magnitude,
the
application
of
chlorsulfuron
to
small
grains,
rangeland
and
pasture
greatly
exceeds
levels
of
concern
for
non­
target
and
endangered/
threatened
plants
found
in
semi­
aquatic
areas
(
wetlands).
The
highest
calculated
RQs
are
from
non­
crop
uses:
industrial
sites
and
pasture/
rangeland
Exposure
from
the
sod/
golf
course
and
nursery
uses
were
not
estimated
due
to
low
overall
usage;
however,
because
the
maximum
application
rates
for
those
uses
are
higher
than
for
the
uses
modeled,
the
LOCs
would
be
exceeded
for
these
uses
as
well.
Direct
exposure
scenarios
were
also
not
calculated,
but
RQs
for
plants
and
endangered
plants
would
be
higher
than
those
estimated
from
exposure
via
spray
drift
or
runoff.
Page
20
of
90
Table
11.
Chlorsulfuron
Risk
Quotients
(
RQs)
for
Non­
Target
Semi­
Aquatic
Areas
(
Wetlands)
Using
a
EC25
of
3.06
x
10
­
5
lbs
ai/
acre
for
Non­
Target
Plants
and
a
NOAEC
of
6.8
x
10
­
6
lbs
ai/
acre
for
Endangered
Plants
(
Using
Sugarbeets,
Seedling
Emergence,
Shoot
Height)
with
Ten
Acres
to
One
Acre
Runoff.

Crop
Appl.
rate
(
lbs
ai/
A)

Single
application
EEC
for
ground
appl.
1
(
lbs
ai/
A)
EEC
for
aerial
appl.
2
(
lbs
ai/
A)
RQs
for
ground
application
RQs
for
aerial
application
Non­
target
plants
3
Endangered
plants
4
Non­
target
plants
5
Endangered
plants
6
Barley
(
post
emergent)
0.016
0.00816
0.0088
267
1200
288
1294
Oats
(
preemergent
0.023
0.01173
0.01265
383
1725
413
1860
Oats
(
postemergent
0.016
0.00816
0.0088
267
1200
288
1294
Wheat
(
preemergent
0.023
0.01173
0.01265
383
1725
413
1860
Wheat
(
postemergent
0.016
0.00816
0.0088
267
1200
288
1294
Pastures
and
rangeland
0.0625
0.03188
0.03438
1042
4688
1123
5056
Fallow
0.016
0.00816
0.0088
267
1200
288
1294
Unimproved
turf
0.012
0.00612
N/
A
200
900
N/
A
N/
A
Unimproved
industrial
turf
0.023
0.01173
N/
A
383
1725
N/
A
N/
A
Non
crop
sites
0.047
0.024
N/
A
783
3530
N/
A
N/
A
Non­
crop
(
industrial
sites)
0.14
0.0714
N/
A
2333
10500
N/
A
N/
A
Non­
crop
land
restoration
0.031
0.01625
N/
A
531
2390
N/
A
N/
A
1/
EEC
for
ground
applications
=
drift
+
runoff
=
total
load
Drift
=
application
rate
(
lbs
ai/
acre)
x
0.01
(
drift)
Runoff
=
application
rate
(
lbs
ai/
acre)
x
0.05
(
based
on
solubility)
x
10
(
10
acres
to
one)
2/
EEC
for
aerial
applications
=
drift
+
runoff
=
total
load
Drift
=
application
rate
(
lbs
ai/
acre)
x
0.05
(
drift)
Runoff
=
application
rate
(
lbs
ai/
acre)
x
0.05
(
based
on
solubility)
x
10
(
10
acres
to
one)
3/
RQ
=
EEC
for
ground
application
/
EC25
4/
RQ
=
EEC
for
ground
application
/
NOAEC
5/
RQ
=
EEC
for
aerial
application
/
EC25
6/
RQ
=
EEC
for
aerial
application
/
NOAEC
Table
12
provides
risk
quotients
for
non­
target
and
endangered
terrestrial
plants.
This
scenario
uses
toxicity
endpoints
from
the
seedling
emergence
study
and
assumes
one
acre
to
one
acre
runoff.
Page
21
of
90
RQs
for
ground
application
of
chlorsulfuron
to
small
grains,
pasture
and
rangeland
range
from
31
to
123
for
non­
target
plants
and
from
141
to
551
for
endangered/
threatened
plants.
RQs
for
aerial
application
to
small
grains,
pasture
and
rangeland
range
from
52
to
204
for
non­
target
plants
and
from
235
to
919
for
endangered/
threatened
plants.
Therefore,
for
this
scenario,
(
which
assumes
one
acre
to
one
acre
runoff),
risk
quotients
for
aerial
applications
are
approximately
67%
higher
than
the
risk
quotients
for
ground
applications.

RQs
for
non­
target
plants
range
from
31
to
204
for
small
grains,
rangeland
and
pasture.
For
endangered
plants
they
range
from
141
to
919.
The
highest
RQs
are
for
non­
crop
industrial
sites
(
275
to
1,235).
The
LOC
for
non­
target
and
endangered
terrestrial
plants
is
1.0.
Therefore,
the
application
of
chlorsulfuron
to
small
grains,
rangeland,
pasture
and
non­
crop
sites
greatly
exceeds
LOCs
for
non­
target
and
endangered/
threatened
terrestrial
plants.
Exposure
from
the
sod/
golf
course
and
nursery
uses
were
not
estimated
due
to
low
overall
usage;
however,
because
the
maximum
application
rates
for
those
uses
are
higher
than
for
the
uses
modeled,
the
LOCs
would
be
exceeded
for
these
uses
as
well.
Direct
exposure
scenarios
were
also
not
calculated,
but
RQs
for
plants
and
endangered
plants
would
be
higher
than
those
estimated
from
exposure
via
spray
drift
or
runoff.
Page
22
of
90
Table
12.
Chlorsulfuron
Risk
Quotients
(
RQs)
for
Non­
Target
and
Endangered
Terrestrial
Plants
Using
an
EC25
of
3.06
x
10
­
5
lbs
ai/
acre
for
Non­
Target
Plants
and
a
NOAEC
of
6.8
x
10
­
6
lbs
ai/
acre
for
Endangered
Plants
(
Using
Sugarbeets,
Seedling
Emergence,
Shoot
Height)
with
One
Acre
to
One
Acre
Runoff.

Crop
Appl.
rate
(
lbs
ai/
A)

Single
application
EEC
for
ground
appl.
1
(
lbs
ai/
A)
EEC
for
aerial
appl.
2
(
lbs
ai/
A)
RQs
for
ground
application
RQs
for
aerial
application
Non­
target
plants
3
Endangered
plants
4
Non­
target
plants
5
Endangered
plants
6
Barley
(
post
emergent)
0.016
0.00096
0.0016
31
141
52
235
Oats
(
preemergent
0.023
0.00138
0.0023
45
203
75
338
Oats
(
postemergent
0.016
0.00096
0.0016
31
141
52
235
Wheat
(
preemergent
0.023
0.00138
0.0023
45
203
75
338
Wheat
(
postemergent
0.016
0.00096
0.0016
31
141
52
235
Pastures
and
rangeland
0.0625
0.00375
0.00625
123
551
204
919
Fallow
0.016
0.00096
0.0016
31
141
52
338
Unimproved
turf
0.012
0.00072
N/
A
24
106
N/
A
N/
A
Unimproved
industrial
turf
0.023
0.00138
N/
A
45
203
N/
A
N/
A
Non
crop
sites
0.047
0.0028
N/
A
92
412
N/
A
N/
A
Non­
crop
(
industrial
sites)
0.14
0.0084
N/
A
275
1235
N/
A
N/
A
Non­
crop
land
restoration
0.031
0.00186
N/
A
61
274
N/
A
N/
A
1/
EEC
for
ground
applications
=
drift
+
runoff
=
total
load
Drift
=
application
rate
(
lbs
ai/
acre)
x
0.01
(
drift)
Runoff
=
application
rate
(
lbs
ai/
acre)
x
0.05
(
based
on
solubility)
2/
EEC
for
aerial
applications
=
drift
+
runoff
=
total
load
Drift
=
application
rate
(
lbs
ai/
acre)
x
0.05
(
drift)
Runoff
=
application
rate
(
lbs
ai/
acre)
x
0.05
(
based
on
solubility)
3/
RQ
=
EEC
for
ground
application
/
EC25
4/
RQ
=
EEC
for
ground
application
/
NOAEC
5/
RQ
=
EEC
for
aerial
application
/
EC25
6/
RQ
=
EEC
for
aerial
application
/
NOAEC
Table
13
provides
RQs
for
non­
target
and
endangered
terrestrial
plants
resulting
from
spray
drift
alone
(
no
runoff).
RQs
resulting
from
aerial
application
of
chlorsulfuron
were
five
times
greater
than
for
ground
application.
RQs
for
non­
target
plants
range
from
40
to
156
for
ground
applications
to
small
grains,
rangeland
and
pasture.
For
endangered
plants
they
range
from
3,507
to
13,698.
For
Page
23
of
90
aerial
applications
RQs
for
non­
target
plants
range
from
200
to
800
for
small
grains,
rangeland
and
pasture.
For
endangered
plants
they
range
from
17,533
to
68,488.
The
toxicity
endpoint
used
in
these
RQ
calculations
was
the
shoot
weight
from
the
vegetative
vigor
study.
If
root
weight
was
used
instead,
the
risk
quotients
would
be
much
higher
(
Appendix
5).
Therefore,
the
application
of
chlorsulfuron
to
small
grains,
rangeland
and
pasture
exceeds
LOCs
for
non­
target
and
endangered/
threatened
terrestrial
plants
by
several
orders
of
magnitude.
For
this
scenario
(
which
assumes
no
runoff),
the
risk
quotients
for
aerial
applications
are
approximately
5
times
higher
than
for
ground
applications.
Exposure
from
the
sod/
golf
course
and
nursery
uses
were
not
estimated
due
to
low
overall
usage;
however,
because
the
maximum
application
rates
for
those
uses
are
higher
than
for
the
uses
modeled,
the
LOCs
would
be
exceeded
for
these
uses
as
well.
Direct
exposure
scenarios
were
also
not
calculated,
but
RQs
for
plants
and
endangered
plants
would
be
higher
than
those
estimated
from
exposure
via
spray
drift
or
runoff.
Page
24
of
90
Table
13.
Chlorsulfuron
Risk
Quotients
(
RQs)
for
Non­
Target
and
Endangered
Terrestrial
Plants
Resulting
From
Drift
Exposure
Alone
(
No
Runoff)
Using
a
EC25
of
4.0
x
10­
6
lbs
ai/
acre
for
Non­
Target
Plants
and
a
EC05
of
4.5625
x
10
­
8
lbs
ai/
acre
for
Endangered
Plants
(
Using
Vegetative
Vigor,
Onion
Shoot
Weight).

Crop
Appl.
rate
(
lbs
ai/
A)

Single
application
EEC
for
ground
appl.
1
(
lbs
ai/
A)
EEC
for
aerial
appl.
2
(
lbs
ai/
A)
RQs
for
ground
application
RQs
for
aerial
application
Non­
target
plants
3
Endangered
plants
4
Non­
target
plants
5
Endangered
plants
6
Barley
(
post
emergent)
0.016
1.6
x
10
­
4
8.0
x
10
­
4
40
3507
200
17533
Oats
(
preemergent
0.023
2.3
x
10
­
4
1.15
x10­
3
58
5040
290
25202
Oats
(
postemergent
0.016
1.6
x
10
­
4
8.0
x
10
­
4
40
3507
200
17533
Wheat
(
preemergent
0.023
2.3
x
10
­
4
1.15
x
10­
3
58
5040
290
25202
Wheat
(
postemergent
0.016
1.6
x
10
­
4
8.0
x
10
­
4
40
3507
200
17533
Pastures
and
rangeland
0.0625
6.25
x
10
­
4
3.13
x
10­
3
156
13698
800
68488
Fallow
0.016
1.6
x
10
­
4
8.0
x
10
­
4
40
3507
200
17533
Unimproved
turf
0.012
1.2
x
10
­
4
N/
A
30
2630
N/
A
N/
A
Unimproved
industrial
turf
0.023
2.3
x
10
­
4
N/
A
58
5040
N/
A
N/
A
Non
crop
sites
0.047
4.7
x
10
­
4
N/
A
118
10300
N/
A
N/
A
Non­
crop
(
industrial
sites)
0.14
1.4
x
10
­
3
N/
A
350
30683
N/
A
N/
A
Non­
crop
land
restoration
0.031
3.1
x
10
­
4
N/
A
78
6794
N/
A
N/
A
1/
EEC
for
ground
applications
=
drift
=
total
load
Drift
=
application
rate
(
lbs
ai/
acre)
x
0.01
(
drift)
2/
EEC
for
aerial
applications
=
drift
=
total
load
Drift
=
application
rate
(
lbs
ai/
acre)
x
0.05
(
drift)
3/
RQ
=
EEC
for
ground
application
/
EC25
4/
RQ
=
EEC
for
ground
application
/
EC05
5/
RQ
=
EEC
for
aerial
application
/
EC25
6/
RQ
=
EEC
for
aerial
application
/
EC05
Page
25
of
90
3.5.3
Terrestrial
Plant
Assessment
for
Contaminated
Irrigation
Water
Risk
quotients
were
also
calculated
to
evaluate
whether
there
is
a
potential
for
adverse
impacts
to
plants
if
exposed
to
irrigation
water
inadvertently
containing
chlorsulfuron.
Modeled
estimates
suggest
that
irrigation
water
from
groundwater
and
surface
water
sources
may
contain
high
enough
levels
of
chlorsulfuron
to
damage
non­
target
plants
and
sensitive
crops
within
irrigated
fields.

Table
14
provides
risk
quotients
for
non­
target
plants
resulting
from
exposure
to
irrigation
water
containing
1.6
ppb
of
chlorsulfuron
in
groundwater,
derived
from
SCIGROW
(
Table
6)
or
6.0
ppb
of
chlorsulfuron
in
surface
water,
generated
using
PRZM/
EXAMS.
The
6.0
ppb
estimate
roughly
covers
North
Dakota,
Texas,
and
Pennsylvania
scenarios,
although
Florida
could
be
as
high
as
9.5
ppb
(
Table
4).

Toxicity
endpoints
from
the
vegetative
vigor
study
were
used
in
the
RQ
calculations
because
it
was
assumed
that
non­
target
plants
are
exposed
to
chlorsulfuron
directly
from
irrigation
water.
This
screening­
level
assessment
indicates
that
irrigation
water
may
inadvertently
contain
high
enough
levels
of
chlorsulfuron
to
adversely
impact
sensitive
agricultural
crops
such
as
soybeans,
sugarbeets,
onions,
etc.
if
they
are
grown
in
fields
that
are
irrigated
with
water
containing
chlorsulfuron.
Risk
quotients
for
sensitive
crops
within
irrigated
fields
range
from
91
for
irrigation
using
groundwater
to
341
for
using
surface
water
to
irrigate
fields.
Since
the
LOC
for
plants
is
1.0,
the
risk
quotients
exceed
the
LOC
by
over
two
orders
of
magnitude.
Therefore,
in
regions
where
chlorsulfuron
has
been
used
historically,
agricultural
crops
grown
in
fields
irrigated
with
groundwater
or
surface
water
containing
chlorsulfuron
may
be
adversely
effected.
For
this
assessment
it
was
assumed
that
there
are
no
endangered
plants
that
occur
within
irrigated
fields.

Table
14.
Risk
Quotients
for
Non­
target
Plants
Resulting
From
Exposure
to
Irrigation
Water
Containing
1.6
ppb
Chlorsulfuron
in
Groundwater
or
6.0
ppb
in
Surface
Water
(
using
the
vegetative
vigor
EC25
of
4.0
x
10
­
6
for
non­
endangered
plants).

Location
EEC:
chlorsulfuron
in
irrigation
groundwater
and
surface
water
(
lbs
ai/
acre)
1
Risk
Quotients
for
groundwater
(
GW)
and
surface
water
(
SW)
irrigation
Non­
Endangered
plants2
(
EEC/
EC
25)

Within
the
irrigated
field1
Groundwater:
3.634
x
10­
4
Surface
water:
1.363
x
10­
3
GW:
91
SW:
341
1/
Estimated
Environmental
Concentration
assuming
1
inch
of
irrigation
water
is
applied
to
the
target
field.
2/
It
is
assumed
that
there
are
no
endangered
plants
within
agricultural
fields
that
are
irrigated.

3.6
Toxicity
Studies
(
from
Public
Literature)

A
number
of
published
reports
suggest
that
chlorsulfuron,
and
other
herbicides
with
the
same
mode
of
action,
may
result
in
delayed
effects
on
crop
yield
and
plant
reproduction
at
levels
lower
than
those
noted
to
cause
short­
term
visible
effects
(
for
a
review
see
Ferenc
2001).
Page
26
of
90
3.6.1
Fletcher
et
al.
1995
The
influence
of
chlorsulfuron
on
the
reproduction
of
green
pea
(
Pisum
sativum)
was
examined
by
exposing
plants
at
three
different
stages
of
development
to
three
different
exposure
levels
(
46,
92,
and
180
mg
ha­
1),
corresponding
to
2
x10­
3,
4
x
10­
3,
and
8
x
10­
3
of
the
recommended
field
application
rates
for
small
grain
crops.
The
most
susceptible
stage
of
development
was
when
plants
possessed
six
expanded
leaves
and
one
visible
flower
bud.
At
that
stage
an
application
rate
of
180
mg
ha­
1
(
0.8%
of
the
recommended
field
rate)
reduced
yield
of
treated
plants
by
99%
of
that
of
control
plants
without
severely
altering
height
or
appearance
of
mature
plants.

When
corresponding
low
application
rates
of
atrazine,
glyphosate,
and
2,4­
D
were
administered
at
this
same
development
stage
there
were
no
effects
on
either
growth
or
reproduction.
Thus
chlorsulfuron
had
an
influence
on
plant
reproduction
that
was
not
produced
by
other
herbicides
at
low
levels.
The
researchers
concluded
that
small
amounts
of
drifting
sulfonylureas
are
potentially
more
damaging
to
the
yield
of
non­
target
plants
than
that
of
other
commonly
used
herbicides.

3.6.2
Coyner
et
al.
2000
The
effect
of
chlorsulfuron
on
the
non­
target
freshwater
macrophyte,
Potamogeton
pectinatus
(
sago
pondweed)
was
evaluated
using
environmental
growth
chambers.
This
ecologically
important
submerged
plant
is
a
food
source
for
many
species
of
wildlife
such
as
ducks,
geese
and
swans,
as
well
as
marsh
and
shorebirds
(
Hurly,
1994).
P.
pectinatus
also
provides
habitat
and
nursery
area
for
many
fish
and
other
aquatic
life.
It
grows
in
regions
where
chlorsulfuron
is
used.

In
this
study
P.
pectinatius
was
exposed
to
chlorsulfuron
at
0.25,
0.50.
1.0
or
2.0
ppb
for
4
weeks.
Plants
exposed
to
0.25
ppb
chlorsulfuron
showed
a
76%
reduction
in
length
and
a
50%
reduction
of
stems
and
leaves
compared
to
control
plants.
Increased
mortality
was
observed
at
1.0
ppb
or
greater.
Correll
and
Wu
(
1982)
found
that
P.
pectinatus
exposed
to
650
ppb
atrazine
for
4
week
period
did
not
have
a
mortality
rate
higher
than
the
control
plants.

Comparing
the
test
results
from
this
study
to
those
from
the
guideline
aquatic
plant
studies
(
Table
9)
suggest
that
vascular
plants
such
as
duckweed
(
Lemna
gibba),
may
be
more
susceptible
to
chlorsulfuron
than
non­
vascular
plants
such
as
the
freshwater
diatom
Navicula
pelliculosa.
Results
of
risk
quotient
calculations
using
the
results
from
Coyner
et
al.
(
2000)
are
presented
in
Section
2.6.1.

3.7
Field
Studies,
Greenhouse
Studies,
and
Incident
Reports
Results
from
a
number
of
field
studies,
greenhouse
studies,
laboratory
studies
and
incident
reports
support
the
conclusion
that
chlorsulfuron
applied
at
labeled
rates
may
result
in
high
risk
to
non­
target
plants
grown
in
the
vicinity
of
application
sites.
Several
of
the
fields
studies
below
were
conducted
by
researchers
from
the
EPA
laboratory
in
Corvalis,
Oregon
and
one
of
the
non­
target
plant
incidents
(
at
Horse
Heaven
Hills)
was
investigated
by
a
researcher
from
the
same
EPA
laboratory.
Page
27
of
90
Several
researchers
have
concluded
that
these
studies
indicate
that
small
quantities
of
the
chemical,
such
as
might
be
found
in
airborne
particles
traveling
long
distances,
may
change
plant
reproduction
without
altering
vegetative
growth.
If
the
effect
of
chlorsulfuron
on
cherry
trees
is
characteristic
of
other
plant
species,
drifting
sulfonylureas
may
severely
reduce
both
the
crop
yields
and
fruit
development
on
native
plants,
an
important
component
of
the
habitat
and
food
web
for
wildlife.

Plant
reproductive
processes
may
be
more
sensitive
to
chlorsulfuron
than
growth
effects.
Low
levels
of
chlorsulfuron
appear
to
adversely
influence
plant
reproduction,
which
is
not
characteristic
of
many
common
herbicides.
If
such
events
are
occurring
in
agriculture,
not
only
will
it
be
difficult
to
recognize
them
but
it
will
be
virtually
impossible
to
prove
that
chlorsulfuron
was
responsible
for
the
episode,
because
the
amounts
of
chlorsulfuron
inducing
yield
reduction
are
often
below
the
detection
level
of
conventional
chemical
analysis.

3.7.1
Field
Studies
Fletcher
et
al.
1993
Researchers
at
the
Oregon
State
University
Lewis­
Brown
Horticulture
Farm
near
Corvallis,
Oregon
investigated
the
influence
of
chlorsulfuron
on
cherry
trees
during
the
fall
of
1991
and
the
spring
of
1992,
by
comparing
the
weight
of
fruit
collected
from
treated
and
control
branches.
Single
applications
of
chlorsulfuron
were
administered
until
wetness
with
a
dual
nozzle
spray
wand
at
five
concentrations
representing
0,
1/
1000th,
1/
500th,
1/
100th,
and
1/
10th
of
the
recommended
tank
mixture
rate
of
chlorsulfuron
for
use
on
small
grain
crops
in
Washington,
Oregon,
and
California.
Three
multiple
applications
experiments
were
also
conducted
at
1­
week
intervals.

Results
indicate
that
exposure
of
the
developing
buds
to
low
levels
of
chlorsulfuron
in
September
caused
the
next
spring's
yield
to
be
reduced
to
15%
of
the
controls.
Spring
treatment
resulted
in
yields
of
treated
branches
of
40%
that
of
controls.
Study
authors
determined
that
the
low
dose
herbicides
are
approximately
100
times
more
toxic
than
herbicides
used
prior
to
1982.
Significant
adverse
effects
on
yields
(
up
to
85%
yield
loss)
was
measured
following
treatment
at,
during,
or
shortly
after
bloom.
These
effects
on
the
full
grown,
woody
perennial
cherry
tree
occurred
from
the
use
of
1/
500th
the
maximum
label
rate
for
chlorsulfuron
herbicide
(
1/
500th
of
1/
3
oz.
ai/
acre).

The
researches
concluded
that
"
the
results
from
this
series
of
experiments
showed
that
at
low
levels
of
chlorsulfuron
(
4.6
x
10­
7
M),
reproduction
of
cherry
trees
was
reduced
without
visible
disruption
of
vegetative
organs.
The
high
sensitivity
cherry
trees
displayed
toward
chlorsulfuron
indicates
that
small
quantities
of
the
chemical,
such
as
might
be
found
in
airborne
particles
traveling
long
distances,
may
change
plant
reproduction
without
altering
vegetative
growth.
If
the
effect
of
chlorsulfuron
on
cherry
trees
is
characteristic
of
other
plants
species,
drifting
sulfonylureas
may
severely
reduce
both
the
crop
yields
and
fruit
development
on
native
plants,
an
important
component
of
the
habitat
and
food
web
for
wildlife".

Bhatti
et
al.
1995
Page
28
of
90
Field
experiments
were
conducted
at
the
Irrigated
Agricultural
Research
and
Extension
Center,
Prosser,
Washington
in
1992
and
1993
to
study
the
effects
of
simulated
chlorsulfuron
drift
by
treating
branches
of
three
cherry
(
Prunus
avium)
cultivars
at
different
growth
stages.
In
single
exposure
experiments,
the
yield
and
quality
of
fruit
decreased
significantly
with
the
increase
of
chlorsulfuron
concentrations.
The
concentrations
correspond
to
1/
900th,
1/
300th,
1/
100th
and
1/
10th
the
field
application
rates
(
23.34
g/
ha)
recommended
for
wheat.
In
multiple
exposure
experiments,
fruit
yield,
fruit
size,
and
color
was
significantly
reduced
with
increasing
chlorsulfuron
concentrations
and
numbers
of
exposures.
The
data
suggest
that
multiple
exposures
of
a
susceptible
cherry
cultivar
to
low
levels
of
chlorsulfuron
at
full
bloom
and
post
bloom
stages
can
reduce
yield
and
delay
maturity
of
cherries
while
increasing
firmness.

The
researchers
concluded
that
these
results
concur
with
the
observations
by
Fletcher
et
al.
(
1993),
in
that
the
toxicity
of
chlorsulfuron
to
cherries
was
correlated
with
concentration
and
reproductive
growth
stage
at
the
time
of
exposure.
However,
if
visible
symptoms
were
not
present,
there
were
no
yield
reductions.
Reproduction
in
cherry
trees
can
be
adversely
affected
by
exposure
to
concentrations
of
chlorsulfuron
substantially
lower
than
field
application
rates.

3.7.2
Greenhouse
Studies
The
influence
of
low
application
rates
of
chlorsulfuron
on
the
growth
and
reproduction
of
four
taxonomically
diverse
plant
species
(
canola,
smart
weed,
soybean,
and
sunflower)
were
examined
(
Fletcher
et
al.
1996).
Exposure
ranged
from
1
x10­
3
to
8
x
10­
3
of
the
recommended
field
rates
for
cereal
crops.
Each
species
received
a
single
application
at
one
of
the
three
different
stages
of
reproduction
development.
The
comparative
effects
of
four
different
herbicides
(
atrazine,
chlorsulfuron,
glyphosate,
and
2,4­
D)
were
determined
in
the
same
manner.

Chlorsulfuron
reduced
the
yields
of
all
plants
tested,
with
the
amount
of
reduction
depending
on
the
time
and
rate
of
application.
For
canola
and
soybean,
applications
of
9.2
x
10­
5
and
1.8
x
10­
4
kg/
ha,
respectively,
reduced
seed
yields
by
92
and
99%
as
compared
to
controls
without
causing
significant
changes
in
vegetative
growth.
These
low
application
rates
are
within
the
range
of
reported
herbicide
drift
levels
and
suggest
that
chlorsulfuron
may
cause
severe
reductions
in
the
yields
of
some
nontarget
crops
if
they
are
subject
to
exposure
at
critical
stages
of
development.
Application
of
other
herbicides
at
comparable
rates
and
stages
of
plant
development
had
no
influence
on
either
canola
or
soybean.

Researchers
concluded
that
chlorsulfuron
and
perhaps
other
sulfonylurea
herbicides
appear
to
have
influences
on
plant
reproduction
which
are
not
characteristic
of
many
common
herbicides.
Low
application
rates
of
chlorsulfuron
influenced
the
reproduction
of
four
taxonomically
diverse
species
in
a
manner
similar
to
that
shown
previously
for
cherries
and
green
pea
(
see
above).
In
this
study,
canola
and
soybean
were
the
most
sensitive
species
to
chlorsulfuron.
Smart
weed,
a
food
source
for
waterfowl,
was
moderately
sensitive
and
sunflower
was
insensitive
except
at
the
highest
application
rate
and
only
one
stage
in
development.
Page
29
of
90
Analysis
of
spray
drift
data
collected
under
field
conditions
have
been
reported
by
Bird
(
1992)
to
range,
depending
on
meteorological
conditions,
from
0.02
to
2%
of
application
at
a
distance
as
great
as
¼
mile
from
the
application
zone.
Since
the
application
rates
of
chlorsulfuron
used
in
this
investigation
fall
withing
this
range,
it
follows
that
there
may
be
occasions
where
chlorsulfuron
may
drift
onto
non­
target
vegetation
and
severely
curtail
yield
without
causing
noticeable
effects
on
the
vegetative
growth
or
foliar
appearance
of
the
non­
target
plants.
If
such
events
are
occurring
in
agriculture,
not
only
will
it
be
difficult
to
recognize
them
but
it
will
be
virtually
impossible
to
prove
that
chlorsulfuron
was
responsible
for
the
episode,
because
the
amounts
of
chlorsulfuron
inducing
yield
reduction
of
soybean
in
this
study
are
below
the
detection
level
of
conventional
chemical
analysis
(
Zahnow,
1982).
The
yield
reduction
that
chlorsulfuron
may
cause
in
crops
such
as
canola
and
soybean
would
not
be
expected
for
the
other
herbicides
examined
in
this
investigation.

Chlorsulfuron
and
other
sulfonylurea
herbicides
are
100
times
more
toxic
to
the
vegetative
growth
of
plants
than
older,
commonly
used
herbicides
such
as
atrazine
and
2,4­
D
(
Beyer,
et
al.
1988).
Results
of
this
greenhouse
study
suggest
that
sulfonylurea
herbicides
are
even
more
toxic
to
plant
reproduction.
If
certain
crops
such
as
soybean
are
exposed
to
chlorsulfuron
concentrations
of
1.8
x
10­
4
kg/
ha
or
higher
at
critical
stages
during
reproductive
development,
chlorsulfuron
may
be
as
much
as
10,000
times
more
toxic
to
yield
than
other
conventional
herbicides
such
as
atrazine
and
2,4­
D.

3.7.3
Non­
target
Plant
Incident
Reports
There
are
three
non­
target
plant
incidents
attributed
to
off­
site
drift
of
chlorsulfuron
(
Glean
®
)
in
the
EPA's
EIIS
incident
database.
One
incident
occurred
in
the
spring
of
1990,
near
Benton
City
Washington
(
Fletcher,
1991).
Orchard
growers
alleged
that
herbicides
applied
to
wheat
fields
in
Horse
Heaven
drifted
onto
orchards
in
Badger
Canyon
and
damaged
cherry,
apple,
plum,
and
apricot
crops.
On
numerous
occasions
between
May
2
and
June
5,
1990
investigators
employed
by
the
state
of
Washington
investigated
allegations
of
herbicide­
drift
damage
in
Badger
Canyon.

A
report
from
the
Washington
State
Dept.
of
Agriculture
(
Fletcher,
1991)
indicated
that
sulfonylureas,
Express
®
and
Glean
®
(
chlorsulfuron)
were
applied
within
a
5­
to
15­
mile
arc
south
and
west
of
Badger
Canyon
on
dates
ranging
from
March
26
to
April
14,
a
time
span
which
coincides
with
flowering
and
fruit
set
for
cherry
trees
in
Badger
Canyon.
The
report
also
indicated
that
the
wind
direction
and
velocity
favored
drift
of
Glean
herbicide
from
Horse
Heaven
Hills
toward
Badger
canyon.
Growers
contended
that
sulfonylurea
herbicides
were
most
likely
to
be
responsible
for
the
damage
because
damage
of
this
magnitude
never
occurred
prior
to
the
use
of
sulfonylurea
herbicides
on
Horse
Heaven
Hills.

Examinations
of
two
cherry
and
one
apricot
orchard
clearly
showed
that
the
crop
was
exceptionally
light
in
1990
with
some
trees
having
virtually
no
fruit.
There
appeared
to
be
less
fruit
on
the
west
side
of
the
orchards,
the
side
facing
Horse
Heaven
Hills.
One
orchard
had
numerous
young
apple
trees
with
leader
stems
showed
growth
abnormalities
typical
of
herbicide
damage.
Fletcher
concluded
that
some
of
the
damage
observed
in
the
orchards,
such
as
viral
infected
leaves,
was
not
due
to
herbicide
drift.
Fruit
loss
may
have
been
due
to
herbicide
drift.
However,
there
is
no
conclusive
evidence,
such
Page
30
of
90
as
analytical
data
showing
the
presence
of
a
sulfonylurea
compound
at
the
site
of
reported
plant
damage,
in
Badger
Canyon.

According
to
another
incident
report
(#
I000230­
001)
in
Benton
WA,
there
was
off­
target
drift
of
aerially
applied
chlorsulfuron
from
a
plateau
devoted
to
wheat
farming.
The
off­
target
movement
approximated
a
front
equivalent
to
one
land
section.
The
drift
allegedly
resulted
in
extensive
crop
damage
to
an
orchard.
Peach
trees
were
severely
damaged,
cherries
and
prunes
suffered
some
damage.
Young
and
old
plantings
were
damaged
alike.
Peaches
were
not
affected.

Consulting
agrologists
were
called
in
to
identify
the
source
of
the
damage.
They
were
able
to
duplicate
the
incident
with
the
original
resulting
damage
to
peaches,
cherries
and
prunes
without
damage
to
pears.
This
was
achieved
through
the
use
of
various
herbicides
and
simulated
drift.
They
were
able
to
narrow
the
herbicide
to
one,
to
pinpoint
the
location
of
the
treated
wheat
crop,
and
duplicate
the
drift
pattern.
The
date
of
this
event
was
not
recorded.
The
certainty
index
in
the
EIIS
report
indicates
that
it
is
highly
probable
that
this
incident
was
caused
by
chlorsulfuron.

A
third
incident
that
was
attributed
to
chlorsulfuron
(
Telar
®
)
and/
or
2,4­
D
occurred
in
Kentucky
during
April­
May,
1994
(#
I001473­
001).
The
report
indicates
that
the
state
highway
department
applied
two
herbicides
to
a
roadway.
Subsequently,
a
farmer
alleged
injury
to
tobacco
seedlings
in
a
nearby
greenhouse.
The
injury
was
described
as
turning
yellow
and
stopping
growth;
a
condition
referred
to
as
lance­
shaped
leaves.
The
EIIS
report
indicates
that
0.016
ppm
of
chlorsulfuron
was
found
in
samples
taken
during
the
incident.
The
certainty
index
indicates
that
this
incident
was
possibly
caused
by
chlorsulfuron
and/
or
2,4­
D.

It
is
often
difficult
to
determine
the
cause
of
plant
damage
because
many
symptoms
of
toxicity
in
plants
appear
similar
to
disease
and
nutrient
deficiencies.
Furthermore,
chlorsulfuron
adversely
effects
plant
growth
and
reproduction
at
such
low
levels
that
detecting
residues
in
plant
tissues
or
in
soil
samples
may
be
extremely
difficult
or
impossible
using
conventional
analytical
methods.

3.8
Risk
Characterization
for
Terrestrial
and
Aquatic
Plants
Chlorsulfuron
Estimated
Environmental
Concentrations
(
EECs)
resulting
from
labeled
use
rates
and
application
methods
greatly
exceed
LOCs
for
non­
target
and
endangered
plants.
Chlorsulfuron
is
very
highly
toxic
to
non­
target
plants,
as
measured
by
an
EC
25
of
4.0
x
10­
6
lbs
a.
i./
acre
and
an
EC
05
of
4.6
x10
­
8
lbs
a.
i.
per
acre
(
vegetative
vigor).
Based
on
available
data,
it
appears
that
the
dose
response
curve
for
chlorsulfuron
is
shallow.
Therefore,
test
concentrations
were
not
low
enough
in
the
seedling
emergence
and
vegetative
vigor
studies
to
determine
the
NOAEC
for
several
plant
species.
More
detailed
summaries
are
provided
in
Appendices
4
and
5.

The
representativeness
of
plants
used
in
phytotoxicity
testing
of
non­
target
naturally
occurring
plants
is
uncertain.
The
range
of
plants
used
in
testing
is
limited
to
annuals
despite
the
fact
that
woody
plants
and
other
perennials
are
commonly
found
in
agricultural
areas.
Moreover,
homogenous
crop
test
plant
seed
lots
lack
the
variation
that
occurs
in
natural
populations,
so
the
test
plants
are
likely
to
have
less
variation
in
response
than
would
be
expected
from
wild
populations.
Page
31
of
90
In
some
instances,
specific
test
species
may
be
indicative
of
an
effect
to
another
naturally
occurring
non­
target
species.
Native
plants
sharing
species,
genus
or
family
affinity
with
the
tested
crop
plant
may
show
similar
levels
of
sensitivity
to
a
pesticide.
For
instance
wild
onions
may
show
similar
sensitivity
to
commercially
grown
onions
to
a
particular
herbicide.
However,
given
the
intensive
breeding
and
selection
that
is
used
to
develop
commercial
strains
of
a
species,
it
is
possible
that
natural
and
commercial
plants
of
the
same
species
may
show
very
different
responses.

A
single
aerial
application
of
chlorsulfuron,
assuming
5%
of
the
applied
drifts
into
non­
target
areas,
results
in
EECs
as
high
as
0.003
lbs
ai/
acre.
Therefore,
RQs
for
cereal,
pasture/
rangeland,
and
fallow
use
sites
based
on
maximum
application
rates
range
up
to
1,042
for
non­
target
plants
and
up
to
68,488
for
endangered
plants.
The
toxicity
endpoint
used
in
these
RQ
calculations
was
the
shoot
weight
from
the
vegetative
vigor
study.
If
root
weight
was
used
instead,
the
risk
quotients
would
be
much
higher
(
Appendix
5).

Several
of
the
non­
agricultural
uses
have
multiple
applications
and
several
chlorsulfuron
product
labels
do
not
specify
important
information
on
maximum
application
rates,
numbers
of
applications,
and
methods
of
application.
The
risk
quotients
in
Tables
10
­
14
were
calculated
assuming
only
one
application
of
chlorsulfuron.
If
multiple
applications
are
assumed,
the
risk
quotients
would
be
higher.

Most
of
the
plant
risk
quotients
are
based
on
toxicity
values
derived
from
the
seedling
emergence
and
vegetative
vigor
study
(
MRID
4258720­
01).
However,
the
test
concentrations
in
this
study
were
not
low
enough
to
determine
the
NOAEC
for
some
endpoints
and
the
EC
25
was
calculated
to
be
lower
than
the
lowest
test
concentration.
Therefore,
the
EC
05
was
used
in
risk
quotients
for
endangered
species
and
the
accuracy
of
this
measurement
is
uncertain.

The
amount
of
time
that
the
LOC
is
exceeded
was
estimated
using
first
order
degradation.
The
results
indicate
that
based
on
maximum
application
rates
and
a
soil
dissipation
half­
life
for
chlorsulfuron
of
60
days
and
using
the
seedling
emergence
endpoint,
the
LOC
for
non­
target
plants
is
exceeded
for
approximately
300
days
following
a
single
application
of
0.016
lbs
ai/
acre
to
small
grains
and
for
well
over
a
year
for
plants
living
in
wetlands
(
Appendix
7).

While
EFED
guideline
laboratory
plant
toxicity
tests
required
by
the
EPA
do
not
include
reproduction
endpoints,
results
of
field
studies
and
green
house
studies
conducted
by
researchers
from
the
EPA
laboratory
in
Corvalis,
Oregon
(
Fletcher
et
al.
1993
and
Fletcher
et
al.
1996)
indicate
that
chlorsulfuron
adversely
effects
plant
reproduction
at
concentrations
likely
to
be
found
in
the
environment.

Additionally,
the
Dupont
Vegetation
Management
Report
of
2002
indicates
that
Telar
DF
®
(
chlorsulfuron)
herbicide
inhibits
seed
formation
and
the
production
of
viable
seed.
This
aspect
is
characteristic
of
Telar
DF
®
herbicide
when
applied
at
the
rosette­
bloom
stages
of
growth.
The
viability
of
weed
seed
is
greatly
reduced
or
eliminated
following
the
application
of
Telar
DF
®
herbicides
when
applied
prior
to
maturation
of
the
seed
embryo.
The
report
also
indicates
that
while
grasses
are
very
tolerant
to
Telar
DF
®
at
early
or
late
stages
of
growth,
it
should
not
be
used
on
grasses
grown
for
seed.
Field
research
and
practical
use
experience
have
demonstrated
that
numerous
Page
32
of
90
desirable
tree
and
shrub
species
(
established
plantings)
have
a
high
degree
of
tolerance
to
Telar
DF
®
from
incidental
soil
residual
contact
when
used
according
to
the
label.
However,
tolerances
to
this
product
varies
from
species
to
species
and
site
considerations.

Another
source
of
uncertainty
is
the
fact
that
current
product
labels
recommend
that
chlorsulfuron
be
tank
mixed
with
other
common
herbicides
to
ensure
that
resistant
weeds
are
killed,
which
may
result
in
synergistic
effects
to
non­
target
plants.
Toxicity
data
on
combinations
of
herbicides
are
lacking.
However,
current
label
precautions
appear
to
suggest
that
synergistic
effects
may
occur
if
chlorsulfuron
is
applied
to
fields
to
which
certain
other
insecticides
have
been
applied.
For
example,
the
label
for
Finesse
®
states
that
"
Finesse
should
not
be
used
within
60
days
of
crop
emergence
if
an
organophosphate
insecticide
(
such
as
"
Di
Syston
®
"
)
was
used
as
an
in­
furrow
treatment,
or
crop
injury
may
result."
Presumably,
neither
of
these
two
pesticides
if
used
alone
will
cause
crop
injury
to
wheat
or
barley.
However,
the
label
for
Finesse
®
indicates
that
they
apparently
do
cause
crop
injury
when
used
together.
The
label
restricts
the
use
of
Finesse
®
plus
Malathion
®
and
the
use
of
Finesse
®
plus
Lorsban
®
in
the
Northwest,
as
crop
injury
may
result.
This
suggests
that
there
may
be
synergistic
effects
to
plants
when
chlorsulfuron
is
applied
to
fields
along
with
organophosphate
insecticides.
The
Finesse
Label
also
indicates
that
"
Tank­
mix
applications
of
Finesse
plus
Assert
may
cause
temporary
crop
discoloration/
stunting
or
injury
when
heavy
rainfall
occurs
shortly
after
application".

Furthermore,
the
extent
to
which
indirect
effects
of
chlorsulfuron
occur
in
relation
to
endangered
terrestrial
and
aquatic
animals
is
uncertain.
Several
field
studies
have
documented
adverse
effects
of
chlorsulfuron
to
cherry
trees
and
other
non­
target
plant
species.
If
these
impacts
are
characteristic
of
native
plant
species,
drifting
chlorsulfuron
may
severely
reduce
growth
and
reproductive
development
of
native
plants,
an
important
component
of
the
habitat
and
food
web
for
endangered
wildlife.

3.8.1
Plants
Exposed
to
Chlorsulfuron
Drift
Non­
target
plants
in
areas
where
chlorsulfuron
is
applied
may
be
exposed
to
short
range
drift
(
1
m
to
1
km)
and/
or
longer
range
drift
(
greater
than
1
km).
Drift
may
result
from
fine
droplets
which
blow
off­
target
before
settling
(
spray
drift)
or
potentially
from
treated
soil
blowing
off­
target
(
secondary
drift).
Although
plants
growing
in
proximity
to
application
sites
are
expected
to
be
at
greatest
risk
of
experiencing
relatively
high
exposures
to
chlorsulfuron,
longer
range
drift
has
been
alleged
to
occur
and
cause
visible
effects
to
terrestrial
plants
(
Felsot
et
al.
1996).
Symptoms
of
chlorsulfuron
exposure
to
non­
target
plants
in
areas
away
from
application
sites
were
documented
during
the
same
time
period
as
spray
applications,
suggesting
that
drift
in
these
instances
was
mostly
due
to
the
movement
of
spray
droplets.

However,
chlorsulfuron
labels
(
e.
g.
Finesse)
include
the
following
precaution:
"
To
reduce
the
potential
for
movement
of
treated
soil
due
to
wind
erosion,
do
not
apply
to
powdery,
dry,
or
light
sandy
soil
until
they
have
been
stabilized
by
rainfall,
trashy
mulch,
reduced
tillage
or
other
cultural
practices.
Injury
to
adjacent
crops
may
result
when
treated
soil
is
blown
onto
land
used
to
produce
crops
other
than
cereal
grains."
Chlorsulfuron
is
persistent
on
soil
at
most
pH's
and
the
majority
of
Page
33
of
90
it
is
applied
to
winter
wheat
(
pre­
or
post­
plant),
which
is
commonly
grown
in
dry
regions.
Therefore,
the
potential
for
treated
soil
to
be
blown
off­
target
and
result
in
exposure
to
non­
target
plants,
should
not
be
discounted.

While
for
some
pesticides,
application
of
fine
sprays
is
important
for
control
of
target
pests,
chlorsulfuron's
solubility,
persistence,
relatively
low
soil
binding,
and
mobility
within
plants
(
Weed
Science
Society
1989)
suggests
that
covering
weeds
evenly
with
fine
droplets
is
not
necessary
to
control
them.
Because
chlorsulfuron
can
move
with
soil
water
and
be
taken
up
by
plant
roots
or
absorbed
through
plant
foliage
and
be
transported
systemically
throughout
the
weed,
relatively
large
droplets
of
chlorsulfuron
contacting
weeds
or
surrounding
soil
are
expected
to
be
effective
in
killing
weeds.
Coarse
sprays
minimize
drift
and
are
not
expected
to
reduce
efficacy.
Chlorsulfuron
product
labels
(
e.
g.
Finesse
®
)
provide
the
following
statement:
"
The
most
effective
way
to
reduce
drift
potential
is
to
apply
large
droplets
(>
150
­
200
microns).
The
best
drift
management
strategy
is
to
apply
the
largest
droplets
that
provide
sufficient
coverage
and
control."
The
language
which
is
standard
on
most
DuPont
pesticide
product
labels
provides
suggestions
of
particular
droplets
sizes
that
reduce
drift
but
do
no
require
the
applicator
to
use
a
specific
droplet
size
spectrum.
Although
a
range
of
droplet
diameters
is
mentioned,
chlorsulfuron
labels
do
not
describe
a
droplet
size
distribution
(
such
as
the
American
Society
of
Agricultural
Engineers
standard
definitions
for
droplet
size)
which
is
more
appropriate
for
describing
spray
quality
in
regard
to
spray
drift.
When
the
product
is
applied
according
to
the
label
directions,
many
fine,
driftable
droplets
may
be
produced
that
do
not
result
in
improved
weed
control
and
result
in
off
target
movement
and
potentially
in
nontarget
plant
damage.

The
distance
that
fine
spray
droplets
may
travel
is
largely
dependent
on
their
size,
release
height,
and
meteorological
conditions
like
wind
speed.
Larger
droplets
tend
to
deposit
in
the
application
area
or
nearby
while
smaller
droplets
may
be
blown
farther
downwind.
Droplet
settling
velocity,
the
speed
at
which
droplets
settle
in
air
without
turbulence,
can
be
useful
for
conveying
the
importance
of
droplet
size
on
off­
target
movement.
While
a
droplet
with
a
diameter
of
1000
µ
m
(
1
mm)
takes
1.3
seconds
to
fall
10
feet
and
would
travel
13.7­
feet
downwind,
in
a
10
mph
wind,
a
100
µ
m
droplet
takes
14
seconds
to
reach
the
ground
and
will
travel
185
feet,
and
a
10
µ
m
droplet
will
take
18
minutes
to
reach
the
ground
and
travel
2.7­
miles
downwind.
These
calculations
are
simplified
in
that
they
don't
take
into
account
vertical
mixing
in
the
atmosphere,
the
range
of
droplet
sizes
produced
by
a
nozzle,
or,
for
aerial
applications,
the
wake
of
aerial
application
equipment.
It
is
possible
to
use
spray
drift
models
better
account
for
these
aspects
of
off­
target
drift.

3.8.2
Plants
in
Semi­
Aquatic
Areas
(
Wetlands)

The
EC
25
for
non­
target
plants
is
3.1
x
10­
5
lbs
ai/
acre
and
the
NOAEC
for
endangered
species
is
6.8
x
10
­
6
lbs
ai/
acre
based
on
the
sugarbeet
seedling
emergence
tests
(
Table
11).
For
a
single
ground
application
of
chlorsulfuron
the
EECs
ranged
from
0.0082
lbs
ai/
acre
for
small
grains
(
wheat,
barley
and
oats)
to
0.032
lbs
ai/
acre
for
pastures
and
rangeland.
These
EECs
are
calculated
assuming
1.0
%
off­
site
drift
and
5.0%
runoff
(
ten
acres
to
one
acre).
Page
34
of
90
The
RQs
for
non­
target
plants
range
from
267
to
383
for
small
grains
up
to
1,042
for
pasture
and
rangeland
and
for
endangered
plants
RQs
range
from
1,200
to
1,725
for
small
grains
up
to
4,688
for
pasture
and
rangeland.
Therefore,
ground
application
of
chlorsulfuron
to
small
grains,
pastures
and
rangeland
greatly
exceed
LOCs
for
non­
target
and
endangered
plants
inhabiting
wetlands
located
near
application
sites.
Based
on
PRZM/
EXAMS
modeling,
estimated
environmental
concentrations
remain
constant;
therefore,
the
LOC
is
exceeded
for
well
over
a
year
(
Appendix
7).
To
calculate
the
EEC
for
aerial
applications,
5.0%
drift
and
5.0%
runoff
(
10
acres
to
one
acre)
are
assumed.
This
results
in
RQs
for
aerial
applications
that
are
approximately
9%
higher
than
for
ground
applications.

In
the
RQ
calculations
it
is
assumed
that
1.0
%
of
the
ground
applied
chlorsulfuron
drifts
to
offsite
areas
and
for
aerial
applications
5.0
%
drifts
offsite.
However,
field
studies
submitted
by
the
Spray
Drift
Task
Force
(
Hewitt
et
al.
2002)
and
others
reviewed
by
EPA
(
Bird
et
al.
1996)
suggest
that
downwind
deposition
from
spray
drift
can
be
higher
or
lower
than
these
values
depending
largely
on
droplet
size
applied,
release
height,
and
wind
speed.
RQs
would
be
higher
if
it
was
assumed
that
a
larger
percent
of
applied
chlorsulfuron
drifts
offsite.
Spray
drift
data
and
models
show
droplets
can
travel
more
than
a
thousand
feet
downwind
(
Teske
et
al.
2002).
Given
the
high
toxicity
of
chlorsulfuron
to
plants,
and
the
distances
that
spray
drift
can
travel,
the
potentially
affected
area
around
a
treated
field
may
be
very
large.

3.8.3
Terrestrial
Plants
(
Seedling
Emergence)

To
calculate
the
RQs
for
terrestrial
plants
the
EC
25
for
non­
target
plants
(
3.1
x
10
­
5
lbs
ai/
acre)
and
the
NOAEC
for
endangered
species
(
6.8
x
10
­
6
lbs
ai/
acre)
were
used
(
Table
12).
For
a
single
ground
application
of
chlorsulfuron
the
EECs
ranged
from
9.6
x
10
­
4
lbs
ai/
acre
for
small
grains
(
wheat,
barley
and
oats)
to
0.0038
lbs
ai/
acre
for
pastures
and
rangeland.
These
EECs
are
calculated
assuming
1.0
%
off­
site
drift
and
5.0%
runoff
(
one
acre
to
one
acre).
The
RQs
for
non­
target
plants
range
from
31
to
45
for
small
grains
up
to
123
for
pasture
and
rangeland.
For
endangered
plants
RQs
range
from
141
to
203
for
small
grains
up
to
551
for
pasture
and
rangeland.
Therefore,
ground
application
of
chlorsulfuron
to
small
grains,
pastures,
and
rangeland
greatly
exceed
risk
LOCs
for
non­
target
and
endangered
plants
inhabiting
areas
near
application
sites.

The
RQs
for
a
single
aerial
application
(
Table
12)
are
approximately
60%
higher
than
for
a
ground
application.
To
calculate
EECs
for
an
aerial
application
of
chlorsulfuron,
5.0%
drift
and
5.0%
runoff
(
one
acre
to
one
acre)
are
assumed.
The
RQs
for
non­
target
plants
range
from
52
to
75
for
small
grains
up
to
204
for
pasture
and
rangeland.
For
endangered
plants
RQs
range
from
235
to
338
for
small
grains
up
to
919
for
pasture
and
rangeland.
Therefore,
aerial
application
of
chlorsulfuron
to
small
grains,
pastures
and
rangeland
greatly
exceeds
risk
LOCs
for
non­
target
and
endangered
plants
inhabiting
areas
near
application
sites.
The
LOC
is
exceeded
for
well
over
a
year
following
chlorsulfuron
application.

3.8.4
Terrestrial
Plants
(
Vegetative
Vigor)

The
vegetative
vigor
EC
25
for
non­
target
plants
(
4.0
x
10
­
6
lbs
ai/
acre)
and
the
EC
05
for
endangered
species
(
4.6
x
10
­
8
lbs
ai/
acre)
were
used
to
calculate
the
RQs
for
terrestrial
plants
(
Table
13).
For
Page
35
of
90
a
single
ground
application
of
chlorsulfuron
the
EECs
ranged
from
1.6
x
10
­
4
lbs
ai/
acre
for
small
grains
(
wheat,
barley
and
oats)
to
6.3
x
10
­
4
lbs
ai/
acre
for
pastures
and
rangeland.
These
EECs
are
calculated
assuming
1.0
%
off­
site
drift
and
no
runoff.
The
risk
quotients
for
non­
target
plants
range
from
40
to
58
for
small
grains
up
to
156
for
pasture
and
rangeland.
For
endangered
plants
RQs
range
from
3,507
to
5,040
for
a
small
grains
up
to
13,698
for
pasture
and
rangeland.
Therefore,
ground
application
of
chlorsulfuron
to
small
grains,
pastures
and
rangeland
exceeds
LOCs
for
nontarget
and
endangered
plants
inhabiting
areas
near
application
sites.

The
RQs
for
a
single
aerial
application
(
Table
13)
are
five
times
higher
than
for
a
ground
application.
To
calculate
the
EEC
for
an
aerial
application,
5.0%
drift
and
no
runoff
was
assumed.
The
risk
quotients
for
non­
target
plants
range
from
200
to
290
for
small
grains
up
to
800
for
pasture
and
rangeland.
For
endangered
plants
RQs
range
from
17,533
to
25,202
for
a
small
grains
up
to
68,488
for
pasture
and
rangeland.
Therefore,
aerial
application
of
chlorsulfuron
to
small
grains,
pastures
and
rangeland
greatly
exceeds
LOCs
for
non­
target
and
endangered
plants
inhabiting
areas
near
application
sites.

Field
studies
conducted
by
researchers
from
the
EPA
laboratory
in
Corvalis
Oregon
have
determined
that
chlorsulfuron
adversely
effects
plant
reproduction
at
concentrations
likely
to
be
found
in
the
environment
(
Fletcher
et
al.
1993
and
Bahatti
et
al.
1995).
However,
laboratory
plant
toxicity
tests
required
by
the
EPA
do
not
include
reproduction
endpoints
and
available
data
evaluating
this
effect
are
very
limited.

Greenhouse
studies
provide
further
evidence
of
potential
adverse
effects
to
non­
target
plants.
Fletcher
et
al.
(
1996)
demonstrated
that
chlorsulfuron
applications
of
9.2
x
10­
5
and
1.8
x
10­
4
kg/
ha,
respectively,
reduced
seed
yields
of
canola
and
soybean
by
92
and
99%,
respectively,
as
compared
to
controls
without
causing
significant
changes
in
vegetative
growth.
These
low
application
rates
are
within
the
range
of
reported
herbicide
drift
levels
and
suggest
that
chlorsulfuron
may
cause
severe
reductions
in
the
yields
of
some
non­
target
crops
if
they
are
subject
to
exposure
at
critical
stages
of
development.
Application
of
other
herbicides
at
comparable
rates
and
stages
of
plant
development
had
no
influence
on
either
canola
or
soybean.

Additionally,
as
discussed
in
Section
3.7.3,
a
non­
target
plant
incident
report
from
the
Washington
State
Dept.
of
Agriculture
(
Fletcher,
1991)
indicates
that
growers
contended
that
sulfonylurea
herbicides,
Express
and
Glean
(
chlorsulfuron)
were
most
likely
responsible
for
damage
to
cherry
trees
in
Badger
Canyon
because
damage
of
this
magnitude
never
occurred
prior
to
the
use
of
sulfonylurea
herbicides
on
Horse
Heaven
Hills.

3.8.5
Plants
Exposed
to
Irrigation
Water
Containing
Chlorsulfuron
Results
of
ground
and
surface
water
modeling
indicate
that
in
regions
where
chlorsulfuron
is
historically
used,
irrigation
water
from
groundwater
or
surface
water
sources
may
contain
levels
of
chlorsulfuron
high
enough
to
adversely
effect
non­
target
plants.
We
are
aware
of
only
one
groundwater
monitoring
study
included
chlorsulfuron
as
an
analyte.
Chlorsulfuron
was
only
detected
in
one
Page
36
of
90
sample
at
the
limit
of
detection;
however,
the
extent
to
which
the
monitoring
occurred
in
the
highest
chlorsulfuron
use
area
was
not
determined.

Risk
quotients
were
also
calculated
for
sensitive
crops
within
irrigated
fields.
It
was
assumed
that
there
are
no
endangered
plants
within
the
irrigated
field.
The
RQs
for
crops
range
from
91
for
irrigation
using
groundwater
to
341
for
using
surface
water
to
irrigate
fields.
Therefore,
in
regions
where
chlorsulfuron
has
been
used
historically,
groundwater
and
surface
water
irrigation
may
result
in
damage
to
agricultural
crops
that
are
sensitive
to
chlorsulfuron.
Irrigation
using
surface
water
increases
the
risk
by
over
a
factor
of
3.

The
above
risk
quotients
were
calculated
assuming
a
one
time
exposure
to
irrigation
water
containing
chlorsulfuron.
If
multiple
irrigation
events
are
assumed,
the
risk
quotients
would
be
higher.
There
may
be
a
need
for
additional
plant
toxicity
tests
to
determine
how
toxicity
resulting
from
relatively
low
concentrations
(
i.
e
1.6
ppb)
of
chlorsulfuron
in
an
inch
of
simulated
irrigation
water
compares
to
the
toxicity
levels
demonstrated
in
the
vegetative
vigor
and
seedling
emergence
studies
that
have
already
been
conducted.

3.8.6
Aquatic
Plants
Several
chlorsulfuron
product
labels
do
not
specify
important
information
on
maximum
application
rates,
numbers
of
applications,
and
methods
of
application.
The
risk
quotients
calculated
in
the
assessment
were
based
on
a
single
application
of
chlorsulfuron
to
various
agricultural
crops.
If
multiple
applications
are
assumed,
risk
quotients
would
be
higher.

The
peak
EECs
(
PRZM/
EXAMS)
based
on
a
single
chlorsulfuron
application
range
from
4.2

g/
L
for
wheat
to
9.5

g/
L
for
turf
(
Table
4).
The
assumptions
used
in
this
modeling
are
provided
in
section
2.2.
The
EC
50
for
Lemna
gibba
is
0.35

g/
L
the
NOAEC
is
0.24

g/
L
(
Table
9).
The
RQs
for
non­
target
aquatic
plants
range
from
12
to
21
and
for
endangered
aquatic
plants
the
RQs
range
from
18
to
40
(
Table
10).
Therefore,
RQs
for
non­
target
and
endangered
aquatic
plants
found
in
water
bodies
adjacent
to
application
sites
exceed
the
LOCs.

Additionally,
results
of
Coyner
et
al.
(
2000)
indicate
that
P.
pectinatius,
exposed
to
chlorsulfuron
at
0.25
ppb
for
4
weeks
showed
a
76%
reduction
in
length
and
a
50%
reduction
of
stems
and
leaves
compared
to
control
plants.
Calculations
using
these
toxicity
values
and
the
above
EECs
result
in
risk
quotients
ranging
from
17
to
30
for
non­
target
aquatic
vascular
plants.

3.8.7
Refined
Assessment
of
Spray
drift
on
non­
target
Terrestrial
Plants
The
following
assessment
is
focused
primarily
on
chlorsulfuron
use
on
crops
and
is
intended
to
accurately
reflect
the
most
important
application
conditions
actually
used
in
applying
chlorsulfuron
to
assess
spray
drift
risks
to
non­
target
plants.
Application
parameters
used
by
aerial
applicators
in
Washington
and
Oregon
were
used
to
estimate
a
range
of
spray
drift
levels
in
this
assessment.
Reports
of
set
ups
for
ground
boom
applications
were
not
available
and
thus
ground
boom
configurations
were
assumed
to
include
the
range
of
values
available
in
the
AgDRIFT
model.
Page
37
of
90
Laboratory
toxicity
data
used
in
this
analysis
were
limited
to
effects
occurring
in
a
relatively
short
amount
of
time
after
a
single
exposure.
A
number
of
published
reports
suggest
that
chlorsulfuron,
and
other
herbicides
with
the
same
mode
of
action,
may
result
in
delayed
effects
on
crop
yield
and
plant
reproduction
at
levels
lower
than
those
noted
to
cause
short­
term
visible
effects
(
for
a
review
see
Ferenc
2001).
If
reproductive
effects
occur
at
similar
or
lower
levels
than
laboratory
phytotoxicity
data
used
in
this
analysis,
delayed
effects
may
occur
at
distances
substantially
greater
than
1000
feet
from
applications.

This
assessment
focuses
on
the
effects
of
spray
drift
on
non­
target
terrestrial
plants.
Exposure
from
chlorsulfuron
runoff
can
also
cause
phytotoxicity
to
non­
target
plants.
Chlorsulfuron's
mobility
and
persistence
in
soil
suggests
that
runoff
may
be
an
important
route
of
exposure
to
non­
target
plants
down
slope
of
application
areas.
Plants
in
up­
slope
areas
are
not
affected
by
runoff
but
may
be
damaged
by
spray
drift.

Use
Pattern
Evaluated
This
refined
assessment
focused
on
chlorsulfuron
use
on
grain
crops,
such
as
wheat.
According
to
the
USGS
and
USDA,
this
use
accounts
for
more
than
98%
of
agricultural
chlorsulfuron
usage.
The
maximum
application
rate
for
wheat
on
the
Glean
product
label
is
0.023
lbs
ai/
acre.
Product
label
rates
for
wheat
are
0.0078
to
0.016
lbs
ai
/
acre
with
application
per
crop
season
(
Finesse
product
label).
Up
to
0.0625
lbs
ai/
acre
may
be
used
on
pasture/
rangeland
and
higher
application
rates
are
allowed
for
industrial
areas.
Use
information
is
summarized
in
Table
1.

Chlorsulfuron
is
applied
as
a
liquid
spray
and,
for
most
uses,
may
be
applied
by
ground
or
air.
Directions
for
ground
applications
to
wheat
(
Glean
label)
suggest
that
spray
volume
should
be
at
least
3
gallons/
acre
for
flat
fan
nozzles
or
20
gallons/
acre
for
Raindrop
or
flood
jet
nozzles.
The
lower
volume
is
presumably
allowed
for
the
flat
fan
nozzle
because
this
commonly
used
nozzle
can
produce
a
fine
enough
spray
to
cover
the
field
with
the
low
volume
of
3
gallons/
acre.
With
a
volume
of
3
gallons/
acre,
a
relatively
coarse
spray
would
result
in
too
few
drops
per
unit
area
to
adequately
distribute
the
herbicide
and
control
weeds
in
that
area.
Raindrop
and
flood
jet
nozzles
are
two
models
of
nozzle
that
can
be
used
to
produce
coarser
sprays.
With
coarser
sprays,
higher
volumes
are
generally
necessary
to
result
in
adequate
coverage
of
treated
fields
and
weeds
for
control.
(
For
information
on
the
design
of
flat
fan
and
flood
jet
nozzles
and
their
relative
drift
levels
see
http://
www.
hardi­
international.
com/
Agronomy/
Educat
ion_
Material/
pdf/
04a.
pdf
or
http://
lancaster.
unl.
edu/
ag/
factsheets/
289.
htm).

DuPont
conducted
a
small
survey
of
aerial
applicators
as
an
indication
of
typical
aerial
application
parameters
(
see
Appendix
9a).
The
DuPont
survey
included
15
aircraft
set
ups
for
chlorsulfuron
applications
in
Washington
and
Oregon.
Reported
in
the
survey
is
the
application
volume
(
gallons
per
acre),
boom
length
(
relative
to
wingspan),
nozzle
type,
nozzle
angle,
aircraft
speed,
spray
pressure,
and
variables
that
were
assumed
in
order
to
calculate
spray
droplet
size.
The
droplets
size
spectra
estimated
from
the
equipment
variables
ranged
from
ASAE
medium
to
ASAE
coarse.
Page
38
of
90
Toxicity
Toxicity
tables
for
the
successive
plant
life
stages
(
seedling
emergence
and
vegetative
vigor)
are
in
Appendix
4
and
5.
The
most
sensitive
species
tested
were
sugarbeet
(
seedling
emergence,
EC
25
3.8
x
10­
5
lbs
ai/
acre)
and
onion
(
vegetative
vigor,
EC
25
4.4x10­
6
lbs/
ai
acre).
The
most
sensitive
effects
measured
in
these
tests
were
reductions
in
shoot
weight
and
plant
height.
The
phytotoxicity
data
was
limited
in
that
the
confidence
in
the
estimated
EC
05
and
NOAEL
was
low.

Non­
target
plants
exposed
to
herbicides
may
be
killed
outright
or
weakened,
reducing
their
fitness.
Non­
lethal
effects
could
cause
plants
to
become
more
susceptible
to
plant
pathogens,
become
less
effective
in
competing
with
sympatric
species,
or
reduce
reproductive
success.
In
instances
where
herbicide
exposure
effects
fertilization
or
seed
production,
reproduction
of
plants
in
the
wild
would
be
expected
to
be
reduced
and
population
level
changes
could
occur.

The
representativeness
of
plants
used
in
phytotoxicity
testing
of
non­
target
naturally
occurring
plants
is
uncertain.
The
range
of
plants
used
in
testing
is
limited
to
annuals
despite
the
fact
that
woody
plants
and
other
perennials
are
commonly
found
in
agricultural
areas.
Moreover,
homogenous
crop
test
plant
seed
lots
lack
the
variation
that
occurs
in
natural
populations,
so
the
test
plants
are
likely
to
have
less
variation
in
response
than
would
be
expected
from
wild
populations.

In
some
instances,
specific
test
species
may
be
indicative
of
an
effect
to
another
naturally
occurring
non­
target
species.
Native
plants
sharing
species,
genus
or
family
affinity
with
the
tested
crop
plant
may
show
similar
levels
of
sensitivity
to
a
pesticide.
For
instance
wild
onions
may
show
similar
sensitivity
to
commercially
grown
onions
to
a
particular
herbicide.
However,
given
the
intensive
breeding
and
selection
that
is
used
to
develop
commercial
strains
of
a
species,
it
is
possible
that
natural
and
commercial
plants
of
the
same
species
may
show
very
different
responses.

Phytotoxicity
Tests
and
Spray
Drift
Spray
drift
exposure
to
plants
away
from
field
edges
is
expected
to
result
in
relatively
few
concentrated
droplets
depositing
on
and
around
plants.
In
contrast,
laboratory
vegetative
vigor
and
seedling
emergence
phytotoxicity
tests,
use
relatively
high
volumes
of
spray
to
better
cover
the
test
plant
or
the
soil
surface.
In
instances
where
an
herbicide's
movement
in
plants
or
soil
is
limited,
the
test
conditions
of
the
phytotoxicity
studies
may
result
in
higher
measured
toxicity
than
would
result
from
spray
drift
away
from
the
field's
edge.
In
the
instance
of
herbicides
that
are
mobile
within
plants
and
soil,
such
as
chlorsulfuron
which
is
mobile
in
soil
and
can
be
transported
throughout
exposed
plants,
the
volume
of
spray
used
for
the
exposure
may
not
alter
the
magnitude
of
the
toxic
effect.

Exposure
Current
Label
Directions
relevant
to
Spray
Drift
Chlorsulfuron
product
labels
have
very
few
restrictions
on
how
and
under
what
conditions
the
product
may
be
applied.
For
instance
there
are
no
droplet
size,
wind
speed,
or
boom
height
Page
39
of
90
restrictions.
The
absence
of
bounds
makes
it
more
difficult
to
determine
what
conditions
should
be
used
for
risk
assessment.
The
absence
of
basic
mandatory
label
language
also
allows
applicators
to
make
unnecessarily
high
drift
applications.
Applicator
common
sense
would
prevent
worst
case
applications
but
may
not
result
in
optimal
applications.
For
instance
it
is
unlikely
that
an
applicator
would
make
a
ground
boom
application
with
a
high
boom
and
a
fine
spray
because
drifting
spray
would
be
visible
and
it
would
be
apparent
that
the
efficiency
of
the
application
was
low.
However,
without
proper
guidance
an
applicator
may
use
a
low
boom
but
a
finer
spray
than
necessary
to
achieve
control.
Under
this
scenario
drifting
spray
would
be
less
visible
but
still
unnecessarily
high.
Specifying
basic
spray
drift
control
measures
provides
applicators
with
the
necessary
information
to
perform
an
effective
and
low­
drift
application
and
risk
assessors
with
the
necessary
information
to
model
drift.

AgDRIFT
Background
AgDRIFT
is
a
computer
model
that
can
be
used
to
estimate
downwind
deposition
of
spray
drift
from
aerial,
ground
boom,
and
orchard
and
vineyard
airblast
applications.
The
model
contains
three
tiers
of
increasing
complexity.
In
Tier
1,
the
user
can
assess
downwind
deposition
from
a
single
application
from
all
three
application
methods
under
default
conditions.
The
current
version
of
AgDRIFT
only
allows
Tier
1
level
analyses
for
ground
and
airblast
application
methods.
In
higher
tiers
more
options
are
available
for
aerial
applications.
The
aerial
portion
of
the
model
is
based
on
a
mechanistic
US
Forest
Service
model
(
AGDISP.
Bilanin
et
al
1989).
The
ground
boom
and
orchard
airblast
portions
are
empirical
models
based
on
data
collected
by
the
Spray
Drift
Task
Force
(
SDTF).
The
SDTF
field
data
were
used
to
validate
the
aerial
portion
of
AgDRIFT
(
Bird
et
al
1996a
and
1996b).
AgDRIFT
was
developed
under
a
cooperative
research
and
development
agreement
between
EPA,
USDA,
and
the
SDTF.

Aerial
AgDRIFT:
The
most
important
factors
affecting
drift
from
aerial
applications
are
spray
quality
(
droplet
size),
release
height,
and
wind
speed.
The
aerial
part
of
the
model
predicts
mean
values
based
on
the
inputs
provided.
The
Tier
1
aerial
results
are
generated
using
the
specified
droplet
size
spectra,
10
foot
release
height,
and
a
10
mph
wind
speed.
When
wind
speed
and/
or
release
height
is
lower
than
the
modeled
values
the
spray
drift
levels
would
be
expected
to
be
lower.
Conversely,
in
instances
where
applications
may
be
made
in
higher
wind
speeds
or
at
a
higher
release
height
these
inputs
may
not
be
adequately
conservative
and
higher
tier
modeling
may
be
necessary.

Ground
boom
sprayers
in
AgDRIFT:
The
most
important
factors
affecting
drift
from
ground
boom
applications
are
spray
quality,
release
height,
and
wind
speed.
The
ground
boom
part
of
AgDRIFT
is
based
on
field
trial
data
from
bare
ground
applications.
The
results
of
the
model
reflect
the
quality
and
conditions
of
the
data
on
which
it
is
based.
The
data
from
the
field
trials
were
grouped
into
categories
by
spray
quality
(
droplet
size)
and
release
height.
Results
from
field
trials
conducted
with
different
wind
speeds
were
averaged.
The
average
wind
speed
over
all
the
trials
was
approximately
10
mph.
AgDRIFT
outputs
for
ground
boom
applications
estimate
the
50th
and
90th
percentile
of
data
collected
from
field
trials.
For
this
analysis
the
50th
percentile
data
was
used.
The
field
trial
data
were
not
corrected
for
incomplete
analytical
recoveries,
suggesting
the
true
mean
deposition
values
would
be
approximately
20%
higher
than
the
model's
deposition
results.
1
Toxicity
slopes
are
calculated
from
dose­
response
relationship
of
chlorsulfuron
on
of
the
test
plant
species.
Species
with
high
(
steep)
slopes
show
large
increases
in
toxicity
from
small
increases
in
exposure.
Species
with
low
(
shallow)
slopes
show
small
increases
in
toxicity
from
relatively
large
increases
in
exposure.

2
A
log
normal
toxicity
distribution
is
assumed.
The
following
equation
is
used
to
calculate
the
various
EC
x
levels:
[
EC
25
/
10­
0.67/
slope]
x
10­
a/
slope
=
EC
x
where
a
=
1.28,
0.84,
0.54,
0.25,
0,
­
0.25,
­
0.54,
­
0.84,
and
­
1.28
for
EC
10,
EC
20,
EC
30,
EC
40,
EC
50,
EC
60,
EC
70,
EC
80,
EC
90,
respectively.

Page
40
of
90
Phytotoxicity
and
Downwind
Distance
Using
the
AgDRIFT
model
(
version
2.01)
and
registrant
submitted
phytotoxicity
data
(
MRID
42587201,
McKelvey
and
Kuratle
1992)
it
is
possible
to
estimate
distances
downwind
from
application
areas
at
which
a
particular
toxic
effect
level
would
be
experienced
by
a
particular
tested
plant
species.
To
make
Figures
2
through
7
below,
EC
25
values
(
for
vegetative
vigor
shoot
weight)
of
the
tested
species
were
used
with
the
toxicity
slope1
from
each
species
to
calculate
EC
10,
EC
20,
EC
30,
to
EC
90
effect
levels2.
These
EC
x
values
were
entered
into
an
Excel
spreadsheet
with
Tier
1
AgDRIFT
(
version
2.01)
deposition
distance
results
and
the
maximum
chlorsulfuron
application
rate
for
pasture/
rangeland
(
0.0625
lbs
ai/
acre).
Excel
then
calculated
estimated
downwind
deposition
levels
for
chlorsulfuron
use
on
pasture/
rangeland
and
compared
the
deposition
values
to
the
EC
x
values
to
identify
the
downwind
distance
at
which
the
EC
x
values
would
be
reached.
Excel
arranged
the
distances
into
three
dimensional
bar
charts
showing
the
downwind
distance
at
which
a
particular
toxicity
level
for
each
species
is
expected
to
occur
under
the
Tier
1
AgDRIFT
conditions
with
the
specified
application
rate.

The
barcharts
shown
in
Figures
2
through
7
are
specific
to
the
maximum
application
rate
for
pasture/
rangeland
(
0.0625
lbs
ai/
acre).
Appendix
9b
contains
phytotoxicity
barcharts
for
a
middle
of
the
range
application
rate
from
the
Finesse
product
label
for
preemergent
spraying
to
wheat
(
0.012
lbs
ai/
acre).
Page
41
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Aerial:
Coarse
Spray
Figure
2.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
an
aerial
application
conducted
with
a
coarse
spray
in
a
10
mph
wind
with
a
10
foot
release
height
at
an
application
rate
of
0.0625
lbs
chlorsulfuron
per
acre.
The
plant
species
listed
on
the
bottom
right
axis
are
test
species
for
which
the
registrant
submitted
phytotoxicity
data
(
the
toxicity
slope
for
cucumber
was
unavailable
so
cucumber
results
are
not
shown).
Page
42
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Aerial:
Medium
Spray
Figure
3.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
an
aerial
application
conducted
with
a
medium
spray
in
a
10
mph
wind
with
a
10
foot
release
height
at
an
application
rate
of
0.0625
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
43
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Ground:
Low
Boom,
Medium­
Coarse
Spray
Figure
4.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium/
coarse
spray
in
an
approximate
10
mph
wind
with
a
2
foot
release
height
at
an
application
rate
of
0.0625
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
44
of
90
10
30
50
70
90
w
heat
t
omato
so
rg
hum
co
rn
p
ea
sug
arb
eet
so
yb
ean
rap
e
o
nion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Ground:
HIgh
Boom,
M
e
d
ium­
Coarse
Spray
Figure
5.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium/
coarse
spray
in
an
approximate
10
mph
wind
with
a
4
foot
release
height
at
an
application
rate
of
0.0625
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
45
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Ground:
Low
Boom,
Medium
Spray
Figure
6.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium
spray
in
an
approximate
10
mph
wind
with
a
2
foot
release
height
at
an
application
rate
of
0.0625
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
46
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Ground:
HIgh
Boom,
Medium
Spray
Figure
7.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium
spray
in
an
approximate
10
mph
wind
with
a
4
foot
release
height
at
an
application
rate
of
0.0625
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
47
of
90
Conclusions
Based
on
the
phytotoxicity
study
results
for
wheat
and
chlorsulfuron
use
sites
such
as
pasture/
range
land,
certain
grass
species
appear
to
be
tolerant
to
acute
chlorsulfuron
effects.
Some
tolerant
species
apparently
are
susceptible
to
reproductive
effects
from
single
exposures
based
on
product
claims
of
inhibiting
seed
head
formation
described
on
some
product
labels.
Because
of
lack
of
data,
reproductive
effects
cannot
be
evaluated
at
this
time.
Available
data
suggest
that
it
is
unlikely
that
field
edges
and
areas
downwind
comprised
of
grass
would
be
greatly
affect
by
acute
effects
of
chlorsulfuron.

Figures
2
through
7
above
show
the
phytotoxicity
downwind
of
chlorsulfuron
applications
is
expected
to
vary
based
on
a
number
of
parameter
including
application
method
(
ground
boom
versus
aerial),
the
droplet
size
spectrum,
and
the
release
height.

Figures
2
through
7
show
effects
(
EC
x
effect
levels)
by
distance,
but
do
not
show
at
what
distance
plants
are
likely
to
be
killed
outright.
When
plants
are
tested
by
pesticide
companies
for
efficacy
generally
a
70%
effect
level
is
considered
to
be
a
threshold
for
lethal
effects
to
a
healthy
weed
(
Pallett
2003).
Thus
the
EC
70
effect
level
can
serve
as
estimate
of
when
non­
target
plants
are
expected
to
have
a
high
likelihood
of
rapid
death
similar
to
the
desired
effect
for
weed
species.

Aerial
Applications
For
aerial
applications,
medium
and
coarse
sprays
are
apparently
the
most
commonly
used
sprays
by
aerial
applicators
in
Washington
and
Oregon
­
see
Appendix
9b.
Medium
spray
is
expected
to
produce
higher
drift
levels
than
coarse
sprays
resulting
in
greater
phytotoxicity
at
greater
downwind
distances.
Using
the
EC
70
as
an
estimate
for
an
exposure
that
would
lead
to
rapid
death,
Figure
3
shows
that
3
of
the
9
tested
species
downwind
of
an
application
with
a
medium
spray
would
be
expected
to
be
killed
soon
after
application
in
an
area
stretching
from
the
edge
of
the
treated
field
to
a
distance
exceeding
1000
feet
downwind
from
the
treatment
area.
Using
a
coarse
spray,
Figure
2
shows
that
2
of
the
9
tested
species
would
be
expected
to
be
killed
from
the
edge
of
the
field
to
a
distance
exceeding
1000
feet
downwind
from
the
treatment
area.
Aerial
applications
with
a
medium
spray
are
expected
to
affect
at
least
8
of
the
9
species
tested
at
the
EC
20
level
or
above
for
shoot
weight
greater
than
1000
feet
downwind
of
applications.
In
other
words,
a
20%
or
more
reduction
in
shoot
weight
would
be
expected
for
at
least
8
of
9
tested
species
for
over
1000
feet
downwind
of
applications
under
the
assumed
conditions.
With
a
coarse
spray,
under
the
same
conditions,
at
least
8
of
the
9
tested
species
are
expected
to
be
affected
at
the
EC
10
level
1000
feet
or
more
downwind
(
i.
e.
a
10%
reduction
in
shoot
weight
in
an
areas
stretching
for
more
than
1000
feet
downwind).

Ground
boom
Applications
In
all
instances
the
ground
boom
applications
modeled
resulted
in
lower
drift
deposition
levels
and
downwind
phytotoxicity
than
modeled
aerial
applications.
Ground
boom
deposition
values
were
affected
by
both
droplet
size
and
release
height.
Spray
drift
and
predicted
off­
target
effects
can
be
Page
48
of
90
reduced
by
lowering
the
release
height
and/
or
increasing
spray
droplet
size.

Under
the
lowest
ground
boom
drift
conditions
allowed
by
AgDRIFT
2.01
(
2
foot
boom
height
and
medium/
coarse
spray),
5
of
9
tested
species
would
be
expected
to
be
rapidly
killed
from
10
to
85
feet
downwind
the
treated
area
(
Fig.
4).
Under
the
same
conditions,
5
of
the
9
tested
species
would
be
affected
at
the
EC
10
level
in
the
area
stretching
for
the
edge
of
the
field
to
beyond
1000
feet
downwind.

Under
the
highest
ground
boom
drift
conditions
(
4
foot
boom
and
medium
spray),
plant
species
would
be
expected
to
be
killed
in
the
area
that
stretches
from
0
to
10
feet
(
for
8
of
9
tested
plants)
and
0
to
500
feet
(
for
the
most
sensitive
tested
plant)
downwind
of
the
treated
field
(
Fig.
7).
Under
the
same
conditions,
6­
7
of
the
10
tested
species
are
expected
to
be
affected
at
the
EC
10
level
at
distances
from
0
to
beyond
1000
feet
downwind.
Tested
species
are
expected
to
be
affected
at
the
90%
effect
level
at
10
feet
(
5
of
9
species)
to
150
feet
(
1
of
9
species)
downwind.

Risk
Characterization
Chlorsulfuron
is
a
selective
herbicide.
Some
species,
such
as
certain
grasses,
are
relatively
tolerant
to
chlorsulfuron
while
other
species
are
sensitive
to
acute
effects
and
reproductive
effects.
If
certain
plants
in
a
plant
community
consisting
of
many
species
are
consistently
selected
against
through
inhibiting
growth,
reducing
reproductive
success,
or
being
killed,
the
sensitive
plant
species
are
likely
to
be
removed
from
the
community.
Plants
under
selective
pressure
are
not
able
to
compete
as
successfully
with
other
plants
for
resources
such
as
light
and
water.
Thus
with
pressure
on
a
particular
group
of
species
other
species
would
be
likely
displace
the
sensitive
species
and
become
more
common.
Changes
in
the
species
composition
in
the
boundaries
of
herbicide­
treated
fields
have
been
noted
in
the
literature
(
Kleijn
and
Snoeijing
1997,
Jobin
et
al
1997).
Given
the
selectivity
of
chlorsulfuron
and
the
drift
potential
associated
with
spray
application
methods,
it
is
expected
that
chlorsulfuron
is
applying
selective
pressure
against
certain
species
downwind
of
application
areas.
The
magnitude
of
the
selective
pressure
is
expected
to
depend
on
the
level
of
drift
as
well
as
the
sensitivity
of
exposed
species.

The
results
of
this
analysis
suggest
that
placing
restrictions
on
droplet
size
for
aerial
applications
and
droplet
size
and
boom
height
for
ground
boom
application
may
reduce
risks
associated
with
chlorsulfuron
applications.
Typical
values
for
both
wind
speed
and
release
height
are
likely
to
vary
geographically
.
Aerial
applicators
balance
low
release
heights
with
flight
safety.
Aerial
applicators
will
generally
use
higher
release
heights
in
hilly
areas
or
fields
with
tall
windbreaks
at
their
boundaries.
For
ground
boom
applications,
high
release
heights
are
used
to
avoid
having
the
ends
of
the
spray
boom
hitting
the
ground
in
uneven
fields
or
when
relatively
high
sprayer
speed
is
desired.
Ground
boom
release
height
can
vary
from
less
than
2
feet
to
more
than
6
feet
above
the
ground
or
crop
canopy.
Average
wind
speed
for
chlorsulfuron
use
areas
vary
with
location
with
higher
wind
speed
occurring
in
plains
states.
Table
15
shows
wind
speeds
ranges
for
some
representative
areas.
Page
49
of
90
Table
15.
Wind
speeds
during
the
windiest
month
of
the
year
for
cities
in
high
agricultural
chlorsulfuron
use
areas.

City,
State
Approximate
location
in
state
Month
Wind
speed
(
mph)

75th
Percentile
50th
Percentile
25th
Percentile
Yakima,
WA
south
central
April
10
6
4.5
Pendleton,
OR
northwestern
April
10.5
6
4.5
North
Platte,
NE
central
southwestern
April
14
11
7
More
wind
speed
data
for
the
above
locations
are
in
Appendix
9c.

Uncertainty
and
Potential
Refinement
of
Risk
Estimates
A
number
of
uncertainties
exist
in
this
assessment
of
potential
effects
of
chlorsulfuron
spray
drift
to
plants.
With
additional
information
it
may
be
possible
to
further
refine
this
assessment.

1)
The
representativeness
of
tested
species
for
non­
target
plant
species
in
chlorsulfuron
use
areas.
In
chlorsulfuron
use
areas
woody
and
other
perennial
species
are
exposed
to
spray
drift
but
their
sensitivity
to
chlorsulfuron
is
uncertain.
Toxicity
data
on
a
wider
range
of
plants
could
be
used
to
reduce
uncertainty
as
to
the
potential
effects
of
chlorsulfuron
on
perennial
and
woody
species
at
field
edges
and
farther
downwind.

2)
The
duration
of
exposure.
Laboratory
data
is
based
on
single
exposures
to
plants
with
observation
continuing
for
two
weeks
after
dosing.
Non­
target
plants
in
chlorsulfuron
use
areas
may
be
exposed
to
multiple
pulses
of
chlorsulfuron.
Data
on
the
effect
of
repeat
exposures
at
environmentally
relevant
levels
could
be
used
to
determine
the
potential
impacts
to
plants
that
are
exposed
to
drift
from
multiple
applications.

3)
The
toxic
endpoint
measured.
Some
chlorsulfuron
product
labels
and
research
on
non­
target
plants
show
chlorsulfuron
negatively
affects
plant
reproduction.
Data
defining
what
exposure
levels
at
various
developmental
stages
result
in
impaired
plant
reproduction
could
be
used
for
assessing
potential
impacts
of
spray
drift
on
plant
reproduction.

4)
The
adequacy
of
laboratory
spraying
treatments
in
representing
spray
drift
far
from
field
boundaries.
Plants
in
laboratory
studies
are
exposed
to
herbicide
in
volumes
of
carrier
that
are
adequate
to
cover
the
test
plants.
Plants
exposed
to
spray
drift
away
from
field
boundaries
would
contact
the
same
amounts
of
herbicides
tested
in
the
laboratory
but
in
much
lower
volumes
of
carrier.
Plants
are
exposed
to
spray
drift
away
far
away
from
the
field
edge
in
discrete
spots
where
droplets
impact
the
plant
foliage
opposed
to
the
diffuse
coating
used
in
lab
studies.
The
effect
of
small
concentrated
exposures
relative
to
diffuse
exposure
is
uncertain.
Data
on
the
effect
of
exposure
volume
on
phytotoxicity
could
be
used
to
refine
effect
level
estimates.
Page
50
of
90
4.
ENDANGERED/
THREATENED
SPECIES
Available
data
indicate
that
chlorsulfuron
does
not
exceed
the
LOC
for
endangered/
threatened
terrestrial
or
aquatic
animals.
However,
the
screening
level
risk
assessment
for
endangered
species
indicates
that
chlorsulfuron
does
exceed
the
endangered
species
level
of
concern
for
endangered
and
threatened
terrestrial
and
vascular
aquatic
plants.
The
endangered
species
assessment
on
all
use
sites
will
be
refined
using
data
submitted
as
a
result
of
this
RED.
Further
analysis
regarding
the
overlap
of
individual
species
with
each
use
site
is
required
prior
to
determining
the
likelihood
of
potential
impact
to
listed
species.
After
the
new
data
are
reviewed,
the
risk
assessment
will
be
refined
and
exceedances
of
levels
of
concern
for
high
risks
to
endangered
species
will
be
addressed.

Chlorsulfuron
was
included
in
the
small
grains
cluster
consultation
with
the
Fish
and
Wildlife
Service
(
FWS)
in
1983.
As
chlorsulfuron's
risks
were
determined
to
be
a
"
no
effect"
determination
with
regard
to
aquatic
and
terrestrial
animals,
Reasonable
and
Prudent
Alternatives
and
Reasonable
and
Prudent
Measures
were
not
provided
for
this
pesticide.
Risks
to
endangered
plants
were
not
considered
in
this
Biological
Opinion.

The
current
risk
assessment
does
not
evaluate
risk
from
direct
application
to
plants.
However,
given
that
endangered
plant
risk
quotients
for
spray
drift
alone
from
aerial
applications
range
from
17.5
thousand
to
68
thousand,
it
is
likely
that
nontarget
plants
receiving
direct
applications
would
be
even
more
vulnerable
to
adverse
effects.

The
Office
of
Pesticide
Programs
recently
published
on
its
web
site
(
http://
www.
epa.
gov/
espp/
consultation/
index.
html),
an
overview
of
our
ecological
risk
assessment
process
for
threatened
and
endangered
species.
Because
of
the
timing
of
that
document
and
the
fact
that
it
still
may
undergo
slight
changes,
the
process
described
therein
was
not
fully
utilized
for
this
screening­
level
endangered
species
risk
assessment.
The
Agency
will
reassess
the
potential
risk
of
chlorsulfuron
use
to
endangered
species
using
the
new
process
at
a
later
date
and
consult
as
appropriate
with
the
U.
S.
Fish
and
Wildlife
Service
and
National
Marine
Fisheries
Service
at
that
time.
Page
51
of
90
5.0
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293­
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Kleijn,
D.,
and
GI
Snoeijing.
1997.
Field
boundary
vegetation
and
the
effects
of
agrochemical
drift:
botanical
change
caused
by
low
levels
of
herbicide
and
fertilizer.
Journal
of
Applied
Ecology
34:
1413­
1425.

Pallett,
K.
Efficacy
testing
processes
in
Industry:
relevance
for
NTTP
assessment.
Efficacy
Data
Workshop.
August
20,
2003.
Office
of
Pesticide
Programs,
Crystal
City,
Arlington,
VA.

Teske,
M.
E.,
S.
L.
Bird,
D.
M.
Esterly,
T.
B.
Curbishley,
S.
L.
Ray,
and
S.
G.
Perry.
AgDRIFT:
A
Model
for
Estimating
Near­
Field
Spray
Drift
from
Aerial
Applications.
Environmental
Toxicology
and
Chemistry.
21(
3)
659­
671.

Weed
Science
Society
of
America.
1989.
Herbicide
Handbook.
Published
by
the
Weed
Science
Society
of
America.
Champaign,
IL.

Zahnow,
E.
W.
1982.
Analysis
of
the
Herbicide
Chlorsulfuron
in
Soil
by
Liquid
Chromatography.
J.
Agric.
Food
Chem.
30:
854­
857.
Page
53
of
90
APPENDIX
1.
PRZM
and
EXAMS
input
files
PRZM
input
for
Florida
Turf
FL
8/
09/
2001
Osceola
County;
Representation
of
the
Lake
Kissimmee/
Indian
River
Region;
MLRA
156A;
Metfile:
W12834.
dvf
[
Daytona
Beach]
(
old:
Met156A.
met)
***
Record
3:
0.78
0
0
25
1
3
***
Record
6
­­
ERFLAG
4
***
Record
7:
0.04
0.303
1
172.8
4
2
600
***
Record
8
1
***
Record
9
1
0.1
10
100
3
74
74
74
0
5
***
Record
9a­
d
1
25
0101
1601
0102
1602
0103
1603
0104
1604
0105
1605
0106
1606
0107
1507
1607
0108
.023
.026
.030
.035
.042
.050
.056
.060
.063
.068
.074
.079
.082
.125
.148
.189
.023
.023
.023
.023
.023
.023
.023
.023
.023
.023
.023
.023
.023
.023
.023
.023
1608
0109
1609
0110
1610
0111
1611
0112
1612
.229
.265
.294
.314
.326
.017
.018
.019
.021
.023
.023
.023
.023
.023
.023
.023
.023
.023
***
Record
10
­­
NCPDS,
the
number
of
cropping
periods
30
***
Record
11
010261
150261
151261
1
010262
150262
151262
1
010263
150263
151263
1
010264
150264
151264
1
010265
150265
151265
1
010266
150266
151266
1
010267
150267
151267
1
010268
150268
151268
1
010269
150269
151269
1
010270
150270
151270
1
010271
150271
151271
1
010272
150272
151272
1
010273
150273
151273
1
010274
150274
151274
1
010275
150275
151275
1
010276
150276
151276
1
010277
150277
151277
1
010278
150278
151278
1
010279
150279
151279
1
010280
150280
151280
1
010281
150281
151281
1
010282
150282
151282
1
010283
150283
151283
1
010284
150284
151284
1
010285
150285
151285
1
010286
150286
151286
1
010287
150287
151287
1
010288
150288
151288
1
010289
150289
151289
1
010290
150290
151290
1
***
Record
12
­­
PTITLE
chlor
­
1
applications
@
0.0625
kg/
ha
***
Record
13
30
1
0
0
***
Record
15
­­
PSTNAM
chlor
***
Record
16
010461
0
2
0.00.0625
0.95
0.16
010462
0
2
0.00.0625
0.95
0.16
010463
0
2
0.00.0625
0.95
0.16
010464
0
2
0.00.0625
0.95
0.16
010465
0
2
0.00.0625
0.95
0.16
Page
54
of
90
010466
0
2
0.00.0625
0.95
0.16
010467
0
2
0.00.0625
0.95
0.16
010468
0
2
0.00.0625
0.95
0.16
010469
0
2
0.00.0625
0.95
0.16
010470
0
2
0.00.0625
0.95
0.16
010471
0
2
0.00.0625
0.95
0.16
010472
0
2
0.00.0625
0.95
0.16
010473
0
2
0.00.0625
0.95
0.16
010474
0
2
0.00.0625
0.95
0.16
010475
0
2
0.00.0625
0.95
0.16
010476
0
2
0.00.0625
0.95
0.16
010477
0
2
0.00.0625
0.95
0.16
010478
0
2
0.00.0625
0.95
0.16
010479
0
2
0.00.0625
0.95
0.16
010480
0
2
0.00.0625
0.95
0.16
010481
0
2
0.00.0625
0.95
0.16
010482
0
2
0.00.0625
0.95
0.16
010483
0
2
0.00.0625
0.95
0.16
010484
0
2
0.00.0625
0.95
0.16
010485
0
2
0.00.0625
0.95
0.16
010486
0
2
0.00.0625
0.95
0.16
010487
0
2
0.00.0625
0.95
0.16
010488
0
2
0.00.0625
0.95
0.16
010489
0
2
0.00.0625
0.95
0.16
010490
0
2
0.00.0625
0.95
0.16
***
Record
17
0
1
0
***
Record
18
0
0
0.5
***
Record
19
­­
STITLE
Adamsville
Sand;
Hydrologic
Group
C
***
Record
20
102
0
0
1
0
0
0
0
0
0
***
Record
26
0
0
0
***
Record
30
4
36
***
Record
33
4
1
2
0.37
0.47
0
0
0
0.0021660.002166
0
0.1
0.47
0.27
7.5
0
2
10
1.44
0.086
0
0
0
0.0021660.002166
0
0.1
0.086
0.036
0.58
0
3
10
1.44
0.086
0
0
0
0.0021660.002166
0
0.1
0.086
0.036
0.58
0
4
80
1.58
0.03
0
0
0
0.0021660.002166
0
5
0.03
0.023
0.116
0
***
Record
40
0
YEAR
10
YEAR
10
YEAR
10
1
1
1
­­­­­
7
YEAR
PRCP
TCUM
0
0
RUNF
TCUM
0
0
INFL
TCUM
1
1
ESLS
TCUM
0
0
1.0E3
RFLX
TCUM
0
0
1.0E5
EFLX
TCUM
0
0
1.0E5
RZFX
TCUM
0
0
1.0E5
PRZM
input
for
Pennsylvania
Turf
PA
Turf;
9/
28/
01
"
York
Co,
MLRA
148;
Metfile:
W14737.
dvf
(
old:
Met148.
met),
***
Record
3:
Page
55
of
90
0.76
0.3
0
12.5
1
3
***
Record
6
­­
ERFLAG
4
***
Record
7:
0.33
0.123
1
172.8
3
12
600
***
Record
8
1
***
Record
9
1
0.1
10
100
3
74
74
74
0
5
***
Record
9a­
d
1
26
0101
1601
0102
1602
0103
1503
1603
0104
1604
0105
1605
0106
1506
1606
0107
1607
.015
.015
.015
.015
.015
.017
.012
.006
.002
.007
.004
.002
.007
.005
.003
.001
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
0108
1608
0109
1609
0110
1610
0111
1611
0112
1612
.005
.003
.003
.005
.009
.013
.013
.014
.014
.015
.110
.110
.110
.110
.110
.110
.110
.110
.110
.110
***
Record
10
­­
NCPDS,
the
number
of
cropping
periods
30
***
Record
11
010461
150461
011161
1
010462
150462
011162
1
010463
150463
011163
1
010464
150464
011164
1
010465
150465
011165
1
010466
150466
011166
1
010467
150467
011167
1
010468
150468
011168
1
010469
150469
011169
1
010470
150470
011170
1
010471
150471
011171
1
010472
150472
011172
1
010473
150473
011173
1
010474
150474
011174
1
010475
150475
011175
1
010476
150476
011176
1
010477
150477
011177
1
010478
150478
011178
1
010479
150479
011179
1
010480
150480
011180
1
010481
150481
011181
1
010482
150482
011182
1
010483
150483
011183
1
010484
150484
011184
1
010485
150485
011185
1
010486
150486
011186
1
010487
150487
011187
1
010488
150488
011188
1
010489
150489
011189
1
010490
150490
011190
1
***
Record
12
­­
PTITLE
chlor
­
1
applications
@
0.0625
kg/
ha
***
Record
13
30
1
0
0
***
Record
15
­­
PSTNAM
chlor
***
Record
16
010461
0
2
0.00.0625
0.95
0.16
010462
0
2
0.00.0625
0.95
0.16
010463
0
2
0.00.0625
0.95
0.16
010464
0
2
0.00.0625
0.95
0.16
010465
0
2
0.00.0625
0.95
0.16
010466
0
2
0.00.0625
0.95
0.16
010467
0
2
0.00.0625
0.95
0.16
010468
0
2
0.00.0625
0.95
0.16
010469
0
2
0.00.0625
0.95
0.16
010470
0
2
0.00.0625
0.95
0.16
010471
0
2
0.00.0625
0.95
0.16
010472
0
2
0.00.0625
0.95
0.16
010473
0
2
0.00.0625
0.95
0.16
010474
0
2
0.00.0625
0.95
0.16
010475
0
2
0.00.0625
0.95
0.16
Page
56
of
90
010476
0
2
0.00.0625
0.95
0.16
010477
0
2
0.00.0625
0.95
0.16
010478
0
2
0.00.0625
0.95
0.16
010479
0
2
0.00.0625
0.95
0.16
010480
0
2
0.00.0625
0.95
0.16
010481
0
2
0.00.0625
0.95
0.16
010482
0
2
0.00.0625
0.95
0.16
010483
0
2
0.00.0625
0.95
0.16
010484
0
2
0.00.0625
0.95
0.16
010485
0
2
0.00.0625
0.95
0.16
010486
0
2
0.00.0625
0.95
0.16
010487
0
2
0.00.0625
0.95
0.16
010488
0
2
0.00.0625
0.95
0.16
010489
0
2
0.00.0625
0.95
0.16
010490
0
2
0.00.0625
0.95
0.16
***
Record
17
0
1
0
***
Record
18
0
0
0.5
***
Record
19
­­
STITLE
"
Glenville,
Silt
Loam,
HYDG:
C"
***
Record
20
102
0
0
1
0
0
0
0
0
0
***
Record
26
0
0
0
***
Record
30
4
36
***
Record
33
4
1
2
0.37
0.47
0
0
0
0.0021660.002166
0
0.1
0.47
0.27
7.5
0
2
10
1.4
0.254
0
0
0
0.0021660.002166
0
0.1
0.254
0.094
1.74
0
3
12
1.4
0.254
0
0
0
0.0021660.002166
0
2
0.254
0.094
1.74
0
4
78
1.8
0.201
0
0
0
0.0021660.002166
0
2
0.201
0.121
0.174
0
***
Record
40
0
YEAR
10
YEAR
10
YEAR
10
1
1
1
­­­­­
7
YEAR
PRCP
TCUM
0
0
RUNF
TCUM
0
0
INFL
TCUM
1
1
ESLS
TCUM
0
0
1.0E3
RFLX
TCUM
0
0
1.0E5
EFLX
TCUM
0
0
1.0E5
RZFX
TCUM
0
0
1.0E5
Page
57
of
90
PRZM
input
for
North
Dakota
Wheat
North
Dakota
Spring
Wheat
MLRA
F56
Cass
County
Bearden
silty
clay
loam
"
Red
River
Valley
of
the
North
MLRA
56
MN,
ND,
SD
1948­
1983;
Metfile:
W14914.
dvf
(
old:
Met56.
met),
***
Record
3:
0.75
0.5
0
12
1
1
***
Record
6
­­
ERFLAG
4
***
Record
7:
0.28
0.17
1
172.8
3
1.5
600
***
Record
8
1
***
Record
9
1
0.1
22
100
1
91
85
87
0
100
***
Record
9a­
d
1
28
0101
1601
0102
1602
0103
1603
0104
1604
2004
0105
0505
1605
0106
1606
0107
1607
.583
.581
.579
.577
.574
.574
.575
.575
.611
.617
.610
.562
.468
.268
.092
.064
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
0108
0508
1008
1608
0109
1609
0110
1610
0111
1611
0112
1612
.065
.036
.098
.110
.126
.139
.152
.162
.168
.170
.171
.171
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
***
Record
10
­­
NCPDS,
the
number
of
cropping
periods
30
***
Record
11
150561
250761
050861
1
150562
250762
050862
1
150563
250763
050863
1
150564
250764
050864
1
150565
250765
050865
1
150566
250766
050866
1
150567
250767
050867
1
150568
250768
050868
1
150569
250769
050869
1
150570
250770
050870
1
150571
250771
050871
1
150572
250772
050872
1
150573
250773
050873
1
150574
250774
050874
1
150575
250775
050875
1
150576
250776
050876
1
150577
250777
050877
1
150578
250778
050878
1
150579
250779
050879
1
150580
250780
050880
1
150581
250781
050881
1
150582
250782
050882
1
150583
250783
050883
1
150584
250784
050884
1
150585
250785
050885
1
150586
250786
050886
1
150587
250787
050887
1
150588
250788
050888
1
150589
250789
050889
1
150590
250790
050890
1
***
Record
12
­­
PTITLE
chlor
­
1
applications
@
0.023
kg/
ha
***
Record
13
30
1
0
0
***
Record
15
­­
PSTNAM
chlor
***
Record
16
050161
0
2
0.0
0.023
0.95
0.16
050162
0
2
0.0
0.023
0.95
0.16
050163
0
2
0.0
0.023
0.95
0.16
050164
0
2
0.0
0.023
0.95
0.16
050165
0
2
0.0
0.023
0.95
0.16
050166
0
2
0.0
0.023
0.95
0.16
050167
0
2
0.0
0.023
0.95
0.16
050168
0
2
0.0
0.023
0.95
0.16
050169
0
2
0.0
0.023
0.95
0.16
050170
0
2
0.0
0.023
0.95
0.16
Page
58
of
90
050171
0
2
0.0
0.023
0.95
0.16
050172
0
2
0.0
0.023
0.95
0.16
050173
0
2
0.0
0.023
0.95
0.16
050174
0
2
0.0
0.023
0.95
0.16
050175
0
2
0.0
0.023
0.95
0.16
050176
0
2
0.0
0.023
0.95
0.16
050177
0
2
0.0
0.023
0.95
0.16
050178
0
2
0.0
0.023
0.95
0.16
050179
0
2
0.0
0.023
0.95
0.16
050180
0
2
0.0
0.023
0.95
0.16
050181
0
2
0.0
0.023
0.95
0.16
050182
0
2
0.0
0.023
0.95
0.16
050183
0
2
0.0
0.023
0.95
0.16
050184
0
2
0.0
0.023
0.95
0.16
050185
0
2
0.0
0.023
0.95
0.16
050186
0
2
0.0
0.023
0.95
0.16
050187
0
2
0.0
0.023
0.95
0.16
050188
0
2
0.0
0.023
0.95
0.16
050189
0
2
0.0
0.023
0.95
0.16
050190
0
2
0.0
0.023
0.95
0.16
***
Record
17
0
1
0
***
Record
18
0
0
0.5
***
Record
19
­­
STITLE
Bearden
silty
clay
loam;
HTDG:
C
***
Record
20
100
0
0
1
0
0
0
0
0
0
***
Record
26
0
0
0
***
Record
30
4
36
***
Record
33
3
1
10
1.4
0.377
0
0
0
0.0021660.002166
0
0.1
0.377
0.207
1.74
0
2
52
1.5
0.292
0
0
0
0.0021660.002166
0
1
0.292
0.132
0.116
0
3
38
1.8
0.285
0
0
0
0.0021660.002166
0
2
0.285
0.125
0.058
0
***
Record
40
0
YEAR
10
YEAR
10
YEAR
10
1
1
1
­­­­­
7
YEAR
PRCP
TCUM
0
0
RUNF
TCUM
0
0
INFL
TCUM
1
1
ESLS
TCUM
0
0
1.0E3
RFLX
TCUM
0
0
1.0E5
EFLX
TCUM
0
0
1.0E5
RZFX
TCUM
0
0
1.0E5
Page
59
of
90
PRZM
input
for
Texas
Wheat
TX
wheat;
8/
13/
2001
"
Winter
wheat
in
Blacklands
prairie
section
of
Texas
grown
on
benchmark
Crockett
soil.
HGRP:
D;
MLRA
87;
Metfile:
W13958.
dvf
(
old:
Met87.
met),
Waco
met
station
"
***
Record
3:
0.71
0.5
0
10
1
3
***
Record
6
­­
ERFLAG
4
***
Record
7:
0.43
0.103
1
172.8
1
3
600
***
Record
8
1
***
Record
9
1
0.1
110
99
3
94
87
88
0
90
***
Record
9a­
d
1
28
0101
1601
0102
1602
0103
1603
0104
1604
0105
1605
0106
1606
2006
0107
1607
0108
.125
.111
.101
.094
.074
.043
.044
.046
.080
.083
.086
.087
.026
.027
.029
.031
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
1608
0109
1009
1609
2009
2509
0110
1610
0111
1611
0112
1612
.033
.035
.110
.119
.266
.318
.318
.293
.218
.187
.163
.136
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
.014
***
Record
10
­­
NCPDS,
the
number
of
cropping
periods
30
***
Record
11
101061
300461
170661
1
101062
300462
170662
1
101063
300463
170663
1
101064
300464
170664
1
101065
300465
170665
1
101066
300466
170666
1
101067
300467
170667
1
101068
300468
170668
1
101069
300469
170669
1
101070
300470
170670
1
101071
300471
170671
1
101072
300472
170672
1
101073
300473
170673
1
101074
300474
170674
1
101075
300475
170675
1
101076
300476
170676
1
101077
300477
170677
1
101078
300478
170678
1
101079
300479
170679
1
101080
300480
170680
1
101081
300481
170681
1
101082
300482
170682
1
101083
300483
170683
1
101084
300484
170684
1
101085
300485
170685
1
101086
300486
170686
1
101087
300487
170687
1
101088
300488
170688
1
101089
300489
170689
1
101090
300490
170690
1
***
Record
12
­­
PTITLE
chlor
­
1
applications
@
0.023
kg/
ha
***
Record
13
30
1
0
0
***
Record
15
­­
PSTNAM
chlor
***
Record
16
150961
0
2
0.0
0.023
0.95
0.16
150962
0
2
0.0
0.023
0.95
0.16
150963
0
2
0.0
0.023
0.95
0.16
150964
0
2
0.0
0.023
0.95
0.16
150965
0
2
0.0
0.023
0.95
0.16
150966
0
2
0.0
0.023
0.95
0.16
150967
0
2
0.0
0.023
0.95
0.16
150968
0
2
0.0
0.023
0.95
0.16
150969
0
2
0.0
0.023
0.95
0.16
Page
60
of
90
150970
0
2
0.0
0.023
0.95
0.16
150971
0
2
0.0
0.023
0.95
0.16
150972
0
2
0.0
0.023
0.95
0.16
150973
0
2
0.0
0.023
0.95
0.16
150974
0
2
0.0
0.023
0.95
0.16
150975
0
2
0.0
0.023
0.95
0.16
150976
0
2
0.0
0.023
0.95
0.16
150977
0
2
0.0
0.023
0.95
0.16
150978
0
2
0.0
0.023
0.95
0.16
150979
0
2
0.0
0.023
0.95
0.16
150980
0
2
0.0
0.023
0.95
0.16
150981
0
2
0.0
0.023
0.95
0.16
150982
0
2
0.0
0.023
0.95
0.16
150983
0
2
0.0
0.023
0.95
0.16
150984
0
2
0.0
0.023
0.95
0.16
150985
0
2
0.0
0.023
0.95
0.16
150986
0
2
0.0
0.023
0.95
0.16
150987
0
2
0.0
0.023
0.95
0.16
150988
0
2
0.0
0.023
0.95
0.16
150989
0
2
0.0
0.023
0.95
0.16
150990
0
2
0.0
0.023
0.95
0.16
***
Record
17
0
1
0
***
Record
18
0
0
0.5
***
Record
19
­­
STITLE
"
Crockett
fine
sandy
loam
­
Fine,
smectic,
thermic
Udertic
Paleustalf
"
***
Record
20
110
0
0
1
0
0
0
0
0
0
***
Record
26
0
0
0
***
Record
30
4
36
***
Record
33
3
1
10
1.6
0.17
0
0
0
0.0021660.002166
0
0.1
0.17
0.06
1.16
0
2
10
1.6
0.17
0
0
0
0.0021660.002166
0
10
0.17
0.06
1.16
0
3
90
1.7
0.247
0
0
0
0.0021660.002166
0
10
0.247
0.127
0.29
0
***
Record
40
0
YEAR
10
YEAR
10
YEAR
10
1
1
1
­­­­­
7
YEAR
PRCP
TCUM
0
0
RUNF
TCUM
0
0
INFL
TCUM
1
1
ESLS
TCUM
0
0
1.0E3
RFLX
TCUM
0
0
1.0E5
EFLX
TCUM
0
0
1.0E5
RZFX
TCUM
0
0
1.0E5
Page
61
of
90
Typical
EXAMS
input
file
(
index
reservoir
shown
here,
farm
pond
differs
only
by
setting
STFLO
to
zero)

set
mode
=
3
set
outfil(
4)
to
Y
set
outfil(
2)
to
N
READ
ENV
C:\
models\
INPUTS\
EXAMSenv\
ir298.
exv
READ
MET
C:\
models\
INPUTS\
Metfiles\
w12834.
dvf
SET
YEAR1
=
1961
recall
chem
1
chemical
name
is
chlor
set
MWT(
1)
=
357.8
set
VAPR(
1)
=
4.6e­
6
set
SOL(
1,1)
=
31800
set
KOC(
1)
=
36
set
QTBAS(*,
1,1)
=
2
set
QTBAW(*,
1,1)
=
2
READ
PRZM
P2E­
C1.
D61
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
RUN
READ
PRZM
P2E­
C1.
D62
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D63
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D64
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D65
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D66
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D67
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D68
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
Page
62
of
90
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D69
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D70
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D71
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D72
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D73
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D74
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D75
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D76
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D77
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D78
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
Page
63
of
90
READ
PRZM
P2E­
C1.
D79
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D80
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D81
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D82
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D83
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D84
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D85
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D86
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D87
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D88
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D89
SET
STFLO(
1,*)
=
22.2104590672629
Page
64
of
90
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
READ
PRZM
P2E­
C1.
D90
SET
STFLO(
1,*)
=
22.2104590672629
set
EVAP(*,*)
=
0.0
set
NPSFL(*,*)=
0.0
set
NPSED(*,*)=
0.0
set
RAIN(*)
=
0.0
CONTINUE
QUIT
Page
65
of
90
APPENDIX
2.
SUMMARY
OF
CHLORSULFURON
TOXICITY
TESTS
FOR
TERRESTRIAL
AND
AQUATIC
ANIMALS.

Study
Type
(%
Active
Ingredient)
Species
Toxicity
Value
(
ai)
Toxicity
Category
MRID/
Acc.#
Author
(
Year)
Study
Classification
Dietary
LC
50
Mallard
duck
(
Anus
platyrhynchos)
LC
50>
5,000
ppm
Practically
nontoxic
099462
(
1979)
Core
Dietary
LC
50
Northern
bobwhite
(
Colinus
virginianus)
LC
50
>
5,000
ppm
Practically
nontoxic
099462
(
1979)
Invalid
1
Acute
Oral
LD
50
Northern
bobwhite
(
Colinus
virginianus)
LD
50>
5,000
mg/
kg
Practically
nontoxic
099462
(
1980)
Core
Acute
Oral
LD
50
Mallard
duck
(
Anus
platyrhynchos)
LD
50>
5,000
mg/
kg
Practically
nontoxic
099462
(
1980)
Core
Avian
Reproduction
Mallard
duck
(
Anus
platyrhynchos)
NOAEL
>
961
ppm
LOAEL
>
961
ppm
N/
A
42634002
Beavers,
J.
B.
et
al.
(
1992)
Core
Avian
Reproduction
Northern
bobwhite
(
Colinus
virginianus)
NOAEL
=
174
ppm
LOAEL
=
961
ppm
N/
A
42634001
Beavers,
J.
B.
et
al.
(
1992)
Core
Rat
two
generation
reproduction
Laboratory
rat
NOAEL
=
35
mg/
kg/
day
N/
A
40089316
N/
A
Rat
acute
oral
Laboratory
rat
LD
50
=
5.5
g/
kg
N/
A
00031406
N/
A
Acute
LC
50
Blue
gill
sunfish
LC
50
>
300
ppm
practically
nontoxic
099462
Core
Acute
LC
50
Channel
catfish
LC
50
>
50
ppm
Practically
nontoxic
099462
Core
Acute
LC
50
Fathead
minnow
LC
50
>
300
ppm
Practically
nontoxic
099462
Core
Acute
LC
50
Rainbow
trout
LC
50
>
250
ppm
Practically
nontoxic
099462
Core
Acute
LC
50
Daphnia
magna
LC
50
>
370
ppm
Practically
nontoxic
099462
Core
Early
life­
stage
Rainbow
trout
NOAEC
=
32
mg/
l
N/
A
419764
Pierson,
K.
B.
(
1991)
Core
Life­
cycle
Daphnia
magna
NOAEC
=
20
mg/
l
N/
A
419764­
08
Hutton,
D.
G.
(
1989)
Supplemental
3
Acute
LC
50
Mysid
(
Mysidopsis
b
LC
50
=
89
mg/
l
slightly
419764­
02
Core
Acute
LC
50
Sheepshead
minnow
(
Cyprinodon
LC
50
>
980
mg/
l
practically
nontoxic
419764­
01
Ward,
T.
J.
and
R.
L.
Core
Embryo­
larvae
Eastern
Oyster
EC
50
=
376
mg/
l
practically
419764­
03
Supplemental
4
Embryo­
larvae
Eastern
Oyster
(
Crassostrea
virginica
EC
50
=
384
ppm
Practically
nontoxic
423286­
01
Ward,
T.
J.
and
R.
L.
Boeri
(
1991)
Core
Acute
contact
Honey
bees
LD
50
>
25
ug/
bee
Practically
421299­
02
Core
Page
66
of
90
1/
Due
to
mortality
in
the
controls,
this
study
is
invalid
and
does
not
fulfil
test
guideline
requirements.
2/
Although
the
reproduction
study
is
unacceptable,
a
NOAEL
was
determined
for
the
effect
of
concern
(
still
births)
and
the
LOAEL
was
356
mg/
kg/
day.
Reproductive
toxicity
was
observed
in
both
generations/
both
litters,
as
evidenced
by
decreased
fertility
of
the
dams.
No
parental
toxicity
was
observed.

3/
This
study
does
not
fulfill
test
guidelines
requirements.
It
is
repairable
if
additional
information
on
the
solvent
control
and
dilution
water
is
submitted.

4/
This
study
does
not
fulfill
test
guideline
requirements
because
mortality
data
were
not
provided
in
the
report.
Page
67
of
90
APPENDIX
3.
ESTIMATED
ENVIRONMENTAL
CONCENTRATIONS
ON
AVIAN
AND
MAMMALIAN
FOOD
ITEMS
(
ppm)
FOLLOWING
A
SINGLE
APPLICATION
AT
1
LB
a.
i./
A
Food
Items
EEC
(
ppm)
Predicted
Maximum
Residue1
EEC
(
ppm)
Predicted
Mean
Residue1
Short
grass
240
85
Tall
grass
110
36
Broadleaf/
forage
plants
and
small
insects
135
45
Fruits,
pods,
seeds,
and
large
insects
15
7
1
Predicted
maximum
and
mean
residues
are
for
a
1
lb
ai/
a
application
rate
and
are
based
on
Hoerger
and
Kenaga
(
1972)
as
modified
by
Fletcher
et
al.
(
1994).
Page
68
of
90
APPENDIX
4.
NON­
TARGET
TERRESTRIAL
PLANT
SEEDLING
EMERGENCE
TOXICITY
(
TIER
II)
FOR
98.2%
CHLORSULFURON
WITH
BUFFER
AND
VALENT
X­
77
SURFACTANT
IN
SOME
SOLUTIONS.

Species
%
ai
Endpoints
NOAEL
/
EC
25
(
lbs
ai/
A)
MRID
No.
Author/
Year
Study
Classification
Cucumber
98.2
Plant
height
Emergence
0.000035
/
0.00025
>
0.00439
/
ND
42587201
McKelvey,
R.
A.,
and
Kuratle,
H.
1992
Supplemental
Pea
Plant
height
Emergence
0.000035
/
0.000113
0.000176
/
0.000281
Rape
Plant
height
Emergence
0.000035
/
0.000113
>
0.00439
/
ND
Soybean
Plant
height
Emergence
0.000875
/
0.0015
>
0.00439
/
ND
Sugarbeet
*
Plant
height
Emergence
0.0000068
/
0.000038
0.000176
/
0.000281
Tomato
Plant
height
Emergence
0.0000351
/
0.000169
>
0.02194
/
ND
Corn
Plant
height
Emergence
<
0.00035
/
0.0003
0.00439
/
0.05
Onion
Plant
height
Emergence
0.000035
/
0.000163
0.000035
/
0.000413
Sorgum
Plant
height
Emergence
0.000163
/
0.00138
>
0.0219
/
ND
*
Used
in
RQ
calculations
Page
69
of
90
APPENDIX
5.
NON­
TARGET
TERRESTRIAL
PLANT
VEGETATIVE
VIGOR
TOXICITY
(
TIER
II)
FOR
98.2%
CHLORSULFURON
WITH
BUFFER
AND
VALENT
X­
77
SURFACTANT
IN
SOME
SOLUTIONS.

Species
%
ai
Endpoints
NOAEL
/
EC
25
(
lbs
ai/
A)
MRID
No.
Author/
Year
Study
Classification
Cucumber
98.2
Plant
height
Shoot
weight
0.000225
/
0.001875
0.001125
/
0.006125
42587201
McKelvey,
R.
A.,
and
Kuratle,
H.
1992
Supplemental
Pea
Plant
height
Shoot
weight
00.00045
/
0.00025
0.000045
/
0.000181
Rape
Plant
height
Shoot
weight
0.000045
/
0.0001
0.0000087
/
0.0002
Soybean
Plant
height
Shoot
weight
0.000045
/
0.0000443
0.0000087
/
0.0000193
Sugarbeet
Plant
height
Shoot
weight
0.0000087
/
0.0002062
0.0000087
/
0.0000268
Tomato
Plant
height
Shoot
weight
0.000045
/
0.002
0.000045
/
0.0005562
Corn
Plant
height
Shoot
weight
0.000225
/
0.000625
0.000225
/
0.0001937
Onion
Plant
height
Shoot
weight
*
0.0000087
/
0.0000368
0.0000087
/
0.0000044
Sorgum
Plant
height
Shoot
weight
0.000225
/
0.002625
<
0.000720
/
0.0001562
Wheat
Plant
height
Shoot
weight
0.001125
/
0.05563
0.02813
/
0.005813
*
The
most
sensitive
parameter
in
the
vegetative
vigor
toxicity
study
was
the
sugarbeet
root
weight
(
EC05
=
1.94
x
10­
8
lbs
ai/
acre
).
However,
the
EC05
for
onion
shoot
weight
(
4.56
x
10­
8
lbs
ai/
acre)
was
used
in
the
risk
assessment
for
endangered
species.
Page
70
of
90
APPENDIX
6.
RQ
CALCULATIONS
FOR
SURFACE
AND
GROUNDWATER
IRRIGATION
To
calculate
risk
quotients
for
plants
when
groundwater
contaminated
by
chlorsulfuron
is
applied
to
crops,
the
following
method
was
used.

If
a
one
acre
field
is
irrigated
with
one
inch
of
water
containing
1.6
ppb
chlorsulfuron,
the
effective
mass
of
chlorsulfuron
applied
to
the
field
is
0.00036
lbs
chlorsulfuron/
acre,
calculated
as
follows:

1.6
µ
g
chlorsulfuron
x
1
kg
x
1
#
x
1
Acre
x
4.356
x
104
ft2
x
1
ft
x
28.32
Liter
Liter
109
µ
g
0.4536
kg
Acre
12
ft3
Therefore,
the
risk
quotients
for
sensitive
crops
within
the
field
that
is
irrigated
with
groundwater
containing
1.6
ppb
chlorsulfuron
and
surface
water
containing
6.0
ppb
are
calculated
as
follows:

Ground
water:
EEC/
EC
25
for
vegetative
vigor
=
0.00036
lbs
ai/
acre
=
91
0.000004
lbs
ai/
acre
Surface
water:
EEC/
EC
25
for
vegetative
vigor
=
0.00136
lbs
ai/
acre
=
341
0.000004
lbs
ai/
acre
Page
71
of
90
APPENDIX
7.
FIRST
ORDER
DEGRADATION
FOR
CHLORSULFURON
Simulation
1.

Initial
test
concentration:
0.00096
(
Based
on
a
single
0.16
lbs
ai/
acre
ground
application
for
small
grains,
5%
drift
and
one
acre
to
one
acre
runoff)

Soil
dissipation
Half­
life:
60
days
Length
of
simulation:
365
days
Day
0
=
0.00096
Day
100
=
3.02E­
04
Day
200
=
9.52E­
05
Day
298
=
3.11E­
05
Day
300
=
3.0E­
05
Day
365
=
1.42E­
05
Maximum
residue
=
9.6E­
04
Average
residue
=
2.25E­
04
Day
298
EEC
=
0.000031
and
the
EC
25
=
0.0000306
(
seedling
emergence)
Day
298
RQ
=
1.0
Therefore,
the
LOC
is
exceeded
for
298
days.

Simulation
2.

Initial
test
concentration:
0.00816
(
Based
on
a
single
0.16
lbs
ai/
acre
application
for
small
grains,
5%
drift
and
ten
acre
to
one
acre
runoff
to
wetlands)

Soil
dissipation
Half­
life:
60
days;
Length
of
simulation:
365
days
Day
0
=
8.16E­
03
Day
100
=
2.57E­
03
Day
200
=
8.10E­
04
Day
300
=
2.55E­
04
Day
365
=
1.20E­
04
Maximum
residue
=
8.16E­
03
Average
residue
=
1.91E­
04
Day
365
EEC
=
0.00012
and
the
EC
25
=
0.0000306
(
seedling
emergence)
Day
365
RQ
=
3.9
Therefore,
the
LOC
is
exceeded
for
well
over
365
days.
Page
72
of
90
APPENDIX
8.
TIER
1
DRINKING
WATER
ASSESSMENT
MEMORANDUM
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES,
AND
TOXIC
SUBSTANCES
PC
Code:
118601
DP
Barcode:
D266073
MEMORANDUM
June
25,
2002
SUBJECT:
Drinking
Water
Assessment
to
Support
TRED
for
Chlorsulfuron
FROM:
Lucy
Shanaman,
Chemist
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
THROUGH:
R.
David
Jones,
Senior
Agronomist
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
Betsy
Behl,
Chief
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
TO:
Jim
Tompkins,
Product
Manager
25
Herbicide
Branch,
Registration
Division
This
memo
presents
the
Tier
I
Drinking
Water
Assessment
for
the
parent
compound,
chlorsulfuron,
calculated
using
FIRST
(
surface
water;
version
1.0,
8/
1/
01)
and
SCIGROW
(
groundwater;
version
1.0,
11/
12/
97)
for
use
in
the
human
health
risk
assessment.
This
assessment
does
not
encompass
degradation
products
of
chlorsulfuron.
For
drinking
water
derived
from
surface
water
sources,
the
acute
(
peak)
value
is
46.8

g/
L
(
ppb),
and
the
chronic
(
average
annual)
value
is
16.4

g/
L
(
ppb),
for
non­
crop,
non­
residential
turf.
The
groundwater
screening
concentrations
for
both
acute
and
chronic
exposure
values
are
3.5

g/
L
(
ppb)
for
non­
crop,
non­
residential
turf.
These
concentrations
were
predicted
from
maximum
label
use
information.
The
reported
values
represent
upper­
bound
estimates
of
the
concentrations
that
might
be
found
in
locations
vulnerable
to
pesticide
contamination,
for
either
surface
water
used
for
drinking
water,
or
in
groundwater,
due
to
the
use
of
chlorsulfuron
on
non­
residential
turf.
Modeling
was
also
done
using
label
information
for
application
to
wheat
crops.
Should
the
results
of
this
assessment
indicate
a
need
for
further
refinement,
or
if
any
degradation
products
become
of
toxicological
concern,
please
contact
us
as
soon
as
possible
so
that
we
may
schedule
a
Tier
II
assessment.
A
more
conservative
estimate
which
included
the
degradation
products,
assuming
both
stability
and
mobility
equal
to
the
parent
compound,
was
also
made.

Table
1.
Modeling
Results
Based
on
Low
Pressure
Ground
Spray
Application
of
Chlorsulfuron
3Concentration
of
Selected
Sulfonylurea,
Sulfonamide,
and
Imidazolinone
Herbicides,
Other
Pesticides,
and
Nutrients
in
71
Streams,
5
Reservoir
Outflows,
and
25
Wells
in
the
Midwestern
United
States,
1998;
Battaglin
WA,
Furlong
ET,
Burkhardt
MR;
U.
S.
Department
of
the
Interior,
U.
S.
Geological
Survey,
Water­
Resources
Investigations
Report
00­
4225,
Denver,
Colorado;
2001.

Page
73
of
90
Model
Concentration
From
Use
on
Wheat
Concentration
From
Use
on
Non­
Residential
Turf
FIRST
Surface
Water
Peak
Day
(
Acute)
1.6
ppb
46.8
ppb
FIRST
Surface
Water
Annual
Average
(
Chronic)
0.55
ppb
16.4
ppb
SCIGROW
Ground
Water
(
Acute
and
Chronic)
Value
0.16
ppb
3.5
ppb
Monitoring
Data:

Chlorsulfuron
was
not
an
analyte
in
the
USGS,
NAWQA
monitoring
program.
Pesticides
in
Groundwater
Database,
A
Compilation
Of
Monitoring
Studies:
1971­
1991
National
Summary,
US
EPA
September
1992,
entries
indicate
that
of
eight
wells
tested,
there
were
no
recorded
detections
of
chlorsulfuron.
An
article
from
the
open
literature
examining
streams,
reservoir
outflows,
and
wells
in
the
Midwestern
United
States3
indicates
that
chlorsulfuron
was
detected
in
5
%,
or
fewer,
of
the
71
streams
tested,
only
detected
in
one
of
the
outflow
samples
from
the
five
reservoirs,
and
was
not
detected
in
groundwater
samples
collected
from
25
wells.
Maximum
concentrations,
measured
using
high
performance
liquid
chromatography
in
tandem
with
mass
spectroscopy
(
HPLC­
MS),
were
less
than
one
µ
g/
L
(
ppb).
The
estimated
reporting
limit
(
MRL)
was
0.010
µ
g/
L.

Environmental
Fate:

Chlorsulforon
is
expected
to
be
very
mobile
in
the
environment.
Laboratory
data
(
soil
thin
layer
chromatography)
indicates
that
the
degradation
product
sulfonamide
is
less
mobile
than
chlorsulfuron,
and
that
triazine
amine
is
less
mobile
than
both
the
parent
compound,
chlorsulfuron,
and
the
degradation
product,
sulfonamide.
However,
a
precise
estimate
of
the
specific
degree
of
mobility
which
can
be
attributed
to
either
of
these
degradation
products
is
undetermined.
Laboratory
studies
indicate
that
chlorsulfuron
is
not
expected
to
be
highly
persistent
in
the
environment.
With
some
exceptions,
reported
concentrations
of
degradation
products
peaked
at
study
termination.
Triazine
amine
concentrations
were
reported
to
peak
relatively
early
in
aerobic
soil
metabolism
studies,
transforming
into
hydroxy
triazine
amine
with
concentrations
increasing
steadily
throughout
the
study.

Drinking
Water
Treatment
Effects:

Primary
water
treatment
is
not
expected
to
remove
chlorsulfuron
from
drinking
water.
The
predicted
high
mobility
of
chlorsulfuron
means
that
it
is
not
expected
to
sorb
appreciably
to
soil
and/
or
sediment,
indicating
that
it
would
not
be
expected
to
be
removed
from
drinking
water
by
either
sedimentation
or
flocculation.
Additionally,
water
treatment
processes
are
more
likely
to
raise
the
pH
during
treatment,
therefore,
hydrolysis
is
not
expected
to
be
a
primary
degradation
pathway.
4http://
www.
epa.
gov/
oppefed1/
models/
water/
index.
htm
5http://
www.
epa.
gov/
oppefed1/
models/
water/
index.
htm
Page
74
of
90
Background
Information
on
FIRST:

FIRST4
is
a
screening
model
designed
by
the
Office
of
Pesticide
Programs
to
estimate
the
concentrations
found
in
drinking
water
from
surface
water
sources
for
use
in
human
health
risk
assessment.
As
such,
it
provides
upper
bound
values
on
the
concentrations
that
might
be
found
in
drinking
water
due
to
the
use
of
a
pesticide.
It
was
designed
to
be
simple
to
use
and
to
only
require
data
which
is
typically
available
early
in
the
pesticide
registration
process.
FIRST
is
a
single
event
model
(
one
runoff
event),
but
can
account
for
spray
drift
from
multiple
applications.
FIRST
is
hardwired
to
represent
the
Index
Reservoir,
a
standard
water
body
used
by
the
Office
of
Pesticide
Programs
to
assess
drinking
water
exposure
(
Hetrick
et
al,
1998).
It
is
based
on
a
real
reservoir
in
Illinois
that
is
known
to
vulnerable
to
pesticide
contamination.
The
single
runoff
event
moves
a
maximum
of
8%
of
the
applied
pesticide
into
the
pond.
This
amount
can
be
reduced
due
to
degradation
on
the
field
and
the
effects
of
binding
to
soil
in
the
field.

Background
Information
on
SCIGROW:

SCIGROW5
(
version
1.0,
November
12,
1997)
provides
a
Tier
1,
groundwater
screening
exposure
value
to
be
used
in
determining
the
potential
risk
to
human
health
from
drinking
water
contaminated
with
the
pesticide.
SCIGROW
estimates
likely
groundwater
concentrations
if
the
pesticide
is
used
at
the
maximum
allowable
rate
in
areas
where
groundwater
is
vulnerable
to
contamination.
In
most
cases,
a
large
majority
of
the
use
area
will
have
groundwater
that
is
less
vulnerable
to
contamination
than
the
areas
used
to
drive
the
SCIGROW
estimate.

Modeling
Inputs
and
Results:

A
conservative
estimate
of
surface
water
EEC's
and
drinking
water
concentrations
were
made
which
would
included
any
possible
degradation
products.
While
laboratory
data
did
indicate
that
some
of
the
degradation
products
were
less
mobile
than
the
parent,
the
results
were
unquantified.
A
conservative
estimate
of
degradate
mobility
equal
to
that
of
the
parent
compound,
chlorsulfuron,
was
made.
In
the
absence
of
any
quantified
biotic
or
abiotic
degradation
date
for
the
transformation
products,
which
generally
reached
the
reported
maximum
at
study
termination,
complete
stability
was
assumed
for
both
parent
and
the
degradates.
This
assumption
assured
that
both
the
parent
compound
and
the
degradation
products
would
be
included
in
the
estimated
surface
water
concentrations.
The
modeling
results
from
FIRST,
using
these
assumed
parameters,
estimates
pre­
treatment
surface
water
concentrations
of
total
chlorsulfuron
residues
(
both
parent
and
degradation
products),
resulting
from
two
applications,
at
60
day
intervals,
of
the
maximum
use
rate
of
LESCO
TFC
Dispersible
Granule
Turf
Herbicide
®
,
at
an
acute
(
peak)
value
of
59.7

g/
L
(
ppb),
and
a
chronic
(
average
annual)
value
of
41.3

g/
L
(
ppb).
Please
note
that
these
values
for
parent,
and
any
possible
degradation
products,
are
more
conservative,
and
replace
the
values
which
were
included
in
the
FQPA
memo.
The
values
reported
at
the
beginning
of
this
memo
are
for
parent
only,
as
Health
Effects
Division
has
indicated
that
only
the
parent
compound
is
of
toxicological
concern.

Table
2
and
Table
3
summarize
the
general
input
values
used
in
the
model
runs
for
FIRST
and
SCIGROW
for
chlorsulfuron,
applied
two
times
by
low
pressure
ground
spray
and
incorporated
to
a
depth
of
3
to
4
inches
for
wheat
crops,
at
a
rate
of
0.0156
pounds
of
active
ingredient
per
acre
for
wheat
crops
and
0.333
pounds
of
active
ingredient
per
acre
for
non­
crop,
non­
residential
turf.
Labeled
non­
crop,
non­
residential
turf
uses
include
industrial
turf
grass
areas
such
as:
airports,
military
installations,
fence
rows,
roadsides,
right­
of­
ways,
lumberyards,
tank
farms,
pipeline
and
utility
right­
ofways
pumping
installations,
railroads,
storage
areas,
plant
sites,
and
other
similar
areas.
Input
parameter
values
were
selected
in
accordance
with
US
EPA
OPP
EFED
water
model
parameter
selection
guidelines,
Guidance
for
Selecting
Input
6
http://
www.
epa.
gov/
oppefed1/
models/
water/
index.
htm
Page
75
of
90
Parameters
in
Modeling
the
Environmental
Fate
and
Transport
of
Pesticides,
Version
II,
February
28,
20026.
In
the
absence
of
anaerobic
metabolism
data,
that
value
was
multiplied
by
two,
as
outlined
in
the
guidelines,
to
generate
an
anaerobic
metabolism
half­
life
of
160
days.
Application
rates
were
obtained
from
submitted
labels.

FIRST
predicted
surface
water
acute
peak
concentrations
of
1.6
ppb
for
wheat
and
46.8
ppb
for
non­
residential
turf.
Chronic
(
average
annual)
concentrations
were
0.55
ppb
for
wheat
and
16.4
ppb
for
non­
residential
turf.
SCIGROW
predicted
groundwater
concentration
s
of
0.16
ppb
for
wheat
and
3.5
ppb
for
non­
residential
turf.
Modeling
results
appear
in
Table
2
and
Table
3.
FIRST
and
SCIGROW
output
files
have
been
appended
to
this
document.

Table
2.
Input
Parameters
for
FIRST
Parameter
Wheat
Crops
Non­
Residential
Turf
Chemical
chlorsulfuron
chlorsulfuron
Water
Solubility
(
pH
7;
25

C)
31,800
mg/
L
31,800
mg/
L
Hydrolysis
Half­
Life
(
pH7)
stable
stable
Aerobic
Soil
Metabolism
Half­
Life
80
days
80
days
Aerobic
Aquatic
Metabolism
Half­
Life
160
days
(
2
x
aerobic
soil
halflife
160
days
(
2
x
aerobic
soil
halflife

Photolysis
Half­
Life
stable
stable
Organic
Carbon
Adsorption
Coefficient
(
Koc)
21
L/
kg
21
L/
kg
Application
Method
ground
spray,
incorporate
3
inches
low
pressure
ground
spray
Application
Rate
0.0156
lbs.
a.
i./
acre
0.33
lbs.
a.
i./
acre
Application
Frequency
2
per
year
2
per
year
Interval
Between
Applications
30
days
60
days
Table
3.
Input
Parameters
for
SCIGROW
Parameter
Wheat
Crops
Non­
Residential
Turf
Chemical
chlorsulfuron
chlorsulfuron
Organic
Carbon
Adsorption
Coefficient
(
Koc)
21
L/
kg
21
L/
kg
Aerobic
Soil
Metabolism
Half­
Life
80
days
80
days
Page
76
of
90
Application
Rate
0.0156
lbs.
a.
i./
acre
0.333
lbs.
a.
i./
acre
Application
Frequency
2
per
year
2
per
year
Page
77
of
90
APPENDIX
I
FIRST
SURFACE
WATER
MODELING
RESULTS
FOR
CHLORSULFURON
OUTPUT
TABLES
FOR
CHLORSULFURON
ON
WHEAT
RUN
No.
1
FOR
CHLORSULFURON
ON
WHEAT
*
INPUT
VALUES
*
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
RATE
(#/
AC)
No.
APPS
&
SOIL
SOLUBIL
APPL
TYPE
%
CROPPED
INCORP
ONE(
MULT)
INTERVAL
Koc
(
PPM
)
(%
DRIFT)
AREA
(
IN)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
.016(
.028)
2
30
21.031800.0
GROUND(
6.4)
56.0
.0
FIELD
AND
RESERVOIR
HALFLIFE
VALUES
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
METABOLIC
DAYS
UNTIL
HYDROLYSIS
PHOTOLYSIS
METABOLIC
COMBINED
(
FIELD)
RAIN/
RUNOFF
(
RESERVOIR)
(
RES.­
EFF)
(
RESER.)
(
RESER.)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
80.00
2
N/
A
.00­
.00
160.00
160.00
UNTREATED
WATER
CONC
(
MICROGRAMS/
LITER
(
PPB))
Ver
1.0
AUG
1,
2001
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
PEAK
DAY
(
ACUTE)
ANNUAL
AVERAGE
(
CHRONIC)
CONCENTRATION
CONCENTRATION
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
1.566
.550
Page
78
of
90
FIRST
SURFACE
WATER
MODELING
RESULTS
FOR
CHLORSULFURON
OUTPUT
TABLES
FOR
CHLORSULFURON
ON
NON­
RESIDENTIAL
TURF
RUN
No.
2
FOR
CHLORSULFURON
ON
NON_
RESIDE
*
INPUT
VALUES
*
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
RATE
(#/
AC)
No.
APPS
&
SOIL
SOLUBIL
APPL
TYPE
%
CROPPED
INCORP
ONE(
MULT)
INTERVAL
Koc
(
PPM
)
(%
DRIFT)
AREA
(
IN)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
.333(
.531)
2
60
21.031800.0
GROUND(
6.4)
87.0
.0
FIELD
AND
RESERVOIR
HALFLIFE
VALUES
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
METABOLIC
DAYS
UNTIL
HYDROLYSIS
PHOTOLYSIS
METABOLIC
COMBINED
(
FIELD)
RAIN/
RUNOFF
(
RESERVOIR)
(
RES.­
EFF)
(
RESER.)
(
RESER.)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
80.00
2
N/
A
.00­
.00
160.00
160.00
UNTREATED
WATER
CONC
(
MICROGRAMS/
LITER
(
PPB))
Ver
1.0
AUG
1,
2001
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
PEAK
DAY
(
ACUTE)
ANNUAL
AVERAGE
(
CHRONIC)
CONCENTRATION
CONCENTRATION
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
46.811
16.446
Page
79
of
90
FIRST
SURFACE
WATER
MODELING
RESULTS
FOR
CHLORSULFURON
AND
DEGRADATION
PRODUCTS
OUTPUT
TABLES
FOR
BOTH
CHLORSULFURON
AND
DEGRADATE
RESIDUES
ON
NON­
RESIDENTIAL
TURF
RUN
No.
1
FOR
chlorsulfuron
and
degradates
ON
industrial
turf
*
INPUT
VALUES
*
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
RATE
(#/
AC)
No.
APPS
&
SOIL
SOLUBIL
APPL
TYPE
%
CROPPED
INCORP
ONE(
MULT)
INTERVAL
Koc
(
PPM
)
(%
DRIFT)
AREA
(
IN)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
.333(
.666)
2
60
21.030000.0
GROUND(
6.4)
87.0
.0
FIELD
AND
RESERVOIR
HALFLIFE
VALUES
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
METABOLIC
DAYS
UNTIL
HYDROLYSIS
PHOTOLYSIS
METABOLIC
COMBINED
(
FIELD)
RAIN/
RUNOFF
(
RESERVOIR)
(
RES.­
EFF)
(
RESER.)
(
RESER.)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
.00
2
N/
A
.00­
.00
.00
.00
UNTREATED
WATER
CONC
(
MICROGRAMS/
LITER
(
PPB))
Ver
1.0
AUG
1,
2001
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
PEAK
DAY
(
ACUTE)
ANNUAL
AVERAGE
(
CHRONIC)
CONCENTRATION
CONCENTRATION
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
59.566
41.344
Page
80
of
90
APPENDIX
II
SCIGROW
GROUND
WATER
MODELING
RESULTS
FOR
CHLORSULFURON
OUTPUT
TABLES
FOR
CHLORSULFURON
ON
NON­
RESIDENTIAL
TURF
RUN
No.
1
FOR
chlorsulfuron
INPUT
VALUES
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
APPL
(#/
AC)
APPL.
URATE
SOIL
SOIL
AEROBIC
RATE
NO.
(#/
AC/
YR)
KOC
METABOLISM
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
.016
2
.031
21.0
80.0
GROUND­
WATER
SCREENING
CONCENTRATIONS
IN
PPB
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
.162135
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
A=
75.000
B=
26.000
C=
1.875
D=
1.415
RILP=
4.847
F=
.716
G=
5.197
URATE=
.031
GWSC=
.162135
SCIGROW
GROUND
WATER
MODELING
RESULTS
FOR
CHLORSULFURON
OUTPUT
TABLES
FOR
CHLORSULFURON
ON
NON­
RESIDENTIAL
TURF
RUN
No.
2
FOR
chlorsulfuron
INPUT
VALUES
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
APPL
(#/
AC)
APPL.
URATE
SOIL
SOIL
AEROBIC
RATE
NO.
(#/
AC/
YR)
KOC
METABOLISM
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
.333
2
.666
21.0
80.0
GROUND­
WATER
SCREENING
CONCENTRATIONS
IN
PPB
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
3.460952
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
A=
75.000
B=
26.000
C=
1.875
D=
1.415
RILP=
4.847
F=
.716
G=
5.197
URATE=
.666
GWSC=
3.460952
Attachment
from
5/
12/
2003
email
from
Jake
Vukich
(
DuPont)
to
Tyler
Lane
(
Chemical
Review
Manager,
Special
Review
and
Reregistration
Division,
OPP,
EPA)
Page
81
of
90
APPENDIX
9a
SURVEY
OF
AERIAL
APPLICATORS
TO
DETERMINE
TYPICAL
AIRCRAFT
SETUPS
Non­
Confidential
Version
of
Attachment
A
to
DuPont
Letter
to
USEPA
Dated
May
2,
2003
In
previous
correspondence
with
EPA
regarding
the
droplet
size
spectrum
expected
for
typical
aerial
applications
of
chlorsulfuron
products,
we
proposed
a
small,
informal
survey
of
aerial
applicators
to
determine
typical
aircraft
setups.
To
that
end,
we
have
obtained
descriptions
of
the
spray
setups
used
on
fifteen
aircraft
from
fourteen
applicators
in
Washington
and
Oregon.

To
minimize
drift,
the
Glean
FC
and
Finesse
labels
specify
the
use
of
solid
stream
nozzles
oriented
straight
back
when
the
product
is
applied
by
air
in
the
vicinity
of
sensitive
crops.
As
shown
in
the
attached
table,
most
of
the
aircraft
were
fitted
with
solid
stream
nozzles
with
a
nozzle
angle
of
0,
as
recommended
on
the
label.

The
drop
size
distribution
was
determined
by
the
USDA
 
ARS
model
implemented
in
AgDRIFT

version
2.04.
The
model
provides
a
drop
size
spectrum
for
a
spray
solution
of
water
containing
0.25%
Triton
X­
100.
In
general,
we
expect
the
drop
size
distribution
from
the
model
to
be
shifted
toward
the
fine
size
distribution
as
compared
to
the
size
distribution
for
typical
agricultural
products.
The
inputs
to
the
model
­
nozzle
type,
orientation
angle,
air
speed,
and
pressure
­
were
supplied
by
the
applicators
or
representative
values
were
selected
as
indicated
in
the
attached
table.

The
drop
size
distributions
were
evenly
split
between
ASAE
medium,
medium
to
coarse,
and
coarse.
The
intent
of
the
label
recommendations
is
to
produce
a
drop
size
spectrum
that
will
minimize
drift,
and
we
anticipated
that
most
of
the
solid
stream
nozzles
and
spray
settings
would
produce
a
coarse
size
distribution.
We
attribute
the
difference
between
our
expectations
and
the
model
results
primarily
to
the
higher
than
expected
air
speed
used
for
applications.
We
expected
that
air
speeds
would
be
in
the
range
of
100­
110
mph,
as
it
was
for
aircraft
14
and
15
in
the
attached
table.
In
contrast,
10
of
the
15
applicators
fly
at
a
speed
of
120
mph
or
higher.
The
droplet
size
distribution
shifts
toward
the
fine
distribution
at
higher
speeds.
For
example,
aircraft
4
flown
at
135
mph
produces
a
medium
to
coarse
size
distribution,
while
at
100
mph
would
produce
a
very
coarse
to
extremely
coarse
size
distribution,
according
to
the
USDA
model.

Since
the
USDA
model
simulates
drop
size
distributions
for
a
spray
solution
with
low
surface
tension,
those
distributions
are
likely
to
show
a
greater
volume
of
fine
droplets
than
would
be
expected
for
typical
products.
Our
experience
in
the
Pacific
Northwest
suggests
that
the
label
recommendations
have
been
successful
in
reducing
drift,
as
compared
to
the
potential
indicated
by
the
drop
size
distributions
predicted
by
the
USDA
model.
Page
82
of
90
Aircraft
Setups
for
Application
of
Chlorsulfuron
Products
in
Washington
and
Oregon
Aircraft
Setup
GPA
Boomlength
Nozzle
type
Angle
Speed
Aircraft
Pressure
Assumed
Variables
Droplet
spectrum
(
ASAE)

1
7
65%
CP
30
deg
plate
0
90­
110
188
Cessna
15
psi
all
orifices,
20­
40psi,
90­

110
mph
Medium
2
5
75%
CP
30
deg
plate
0
110­
120
Airtractor
AT
400
&
502
all
orifices,
20­
40psi,
110­

120
mph
Medium
3
5
75%
D­
8
0
115
Thrush
S2R­
6
DC46
core,
40
psi
Coarse
4
3
68%
Lund
multi­
tip
8
0
135
Turbine
Thrush
40
psi
Medium
to
coarse
5
3
70%
CP
0
deg
0
125­
130
Super
Doer
Thrush
all
orifices,
40
psi
Medium
to
coarse
6
3
68%
Lund
multi­
tip
­
8
0
130
502
&
802
Air
Tractor
40
psi
Medium
to
coarse
7
5
68%
D­
8
0,10
100­
110
Agcat
G164
Super
B
40
psi
Coarse
8
3
68%
CP
Straight
Stream
0
135
Super
Doer
1200
Wright
1820
40
psi
Medium
to
coarse
9
3
68%
Spray
Systems
D­

7
no
core
0
120­
125
Cessna
Husky
20
psi
Medium
10
3
to
5
68%
D8,
10,
or
12
35
120
Airtractor
AT502
­

turbine
DC46
core,
40
psi
Medium
11
5
67%
CP
.171
15deg
plate
15
120
Agcat
25
psi
used
5
°
plate,
15
not
in
model
Medium
12
5
67%
D10/
46
0
120
Airtractor
AT502
­

turbine
30
psi
Medium
to
coarse
13
5
67%
D10
0
120
Airtractor
AT502
­

turbine
DC46
core,
40
psi
Coarse
14
3
68%
CP
solid
stream,

no
plate
0
115
Air
tractor
40
psi
Coarse
Page
83
of
90
10
20
30
40
50
60
70
80
90
w
heat
tomato
sorghum
c
orn
pea
sugarbee
t
s
oybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
P
erc
ent
Effe
c
t
No
­
Spr
ay
Z
on
e
(
f
t
)
Ae
rial:
C
oarse
Spray
15
7.5
60%
CP
solid
stream,

no
plate
0
105­
115
Turbo
Agcat
22
psi
Coarse
APPENDIX
9b
PHYTOTOXICITY
RESULTING
FROM
SPRAY
DRIFT
DURING
A
MEDIUM
APPLICATION
RATE
Finesse
product
applications
to
preemergent
wheat.
The
application
ranges
from
0.0078
to
0.016
lbs
ai/
acre.
The
mean
of
the
high
and
low
values
was
used
for
these
graphs.

Figure
8.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
an
aerial
application
conducted
with
a
coarse
spray
in
a
10
mph
wind
with
a
10
foot
release
height
at
an
application
rate
of
0.012
lbs
chlorsulfuron
per
acre.
The
plant
species
listed
on
the
bottom
right
axis
are
test
species
for
which
the
registrant
submitted
phytotoxicity
data
(
the
toxicity
slope
for
cucumber
was
unavailable
so
cucumber
results
are
not
shown).
Page
84
of
90
10
20
30
40
50
60
70
80
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
200
400
600
800
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Aerial:
Medium
Spray
Figure
2.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
an
aerial
application
conducted
with
a
medium
spray
in
a
10
mph
wind
with
a
10
foot
release
height
at
an
application
rate
of
0.012
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
85
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Ground:
Low
Boom,
Medium­
Coarse
Spray
Figure
3.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium/
coarse
spray
in
an
approximate
10
mph
wind
with
a
2
foot
release
height
at
an
application
rate
of
0.012
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
86
of
90
10
30
50
70
90
w
heat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Ground:
HIgh
Boom,
Medium­
Coarse
Spray
Figure
4.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium/
coarse
spray
in
an
approximate
10
mph
wind
with
a
4
foot
release
height
at
an
application
rate
of
0.012
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
87
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effec
t
No­
Spray
Zone
(
ft)
Ground:
Low
Boom,
Medium
Spray
Figure
5.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium
spray
in
an
approximate
10
mph
wind
with
a
2
foot
release
height
at
an
application
rate
of
0.012
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
88
of
90
10
30
50
70
90
wheat
tomato
sorghum
corn
pea
sugarbeet
soybean
rape
onion
0
100
200
300
400
500
600
700
800
900
1000
Percent
Effect
No­
Spray
Zone
(
ft)
Ground:
HIgh
Boom,
Medium
Spray
Figure
6.
Predicted
phytotoxicity
levels
and
associated
downwind
distances
from
a
ground
boom
application
conducted
with
a
medium
spray
in
an
approximate
10
mph
wind
with
a
4
foot
release
height
at
an
application
rate
of
0.012
lbs
chlorsulfuron
per
acre.
The
toxicity
slope
for
cucumber
was
unavailable.
Page
89
of
90
APPENDIX
9c
PHYTOTOXICITY
RESULTING
FROM
SPRAY
DRIFT
DURING
A
MEDIUM
APPLICATION
RATE
Estimated
agricultural
usage
of
chlorsulfuron
from
the
US
Geological
Survey
(
http://
ca.
water.
usgs.
gov/
pnsp/
use92/
chlrsulf.
html):

Wind
speed
data
for
three
representative
cities
in
areas
where
chlorsulfuron
is
used
agriculturally.
Graphs
show
75th,
50th,
and
25th
percentile
wind
speeds
for
each
month.
Wind
speed
data
is
from
SAMSON
weather
monitoring
stations.

Yakima,
south
central
Washington:
Page
90
of
90
Pendleton,
northwestern
Oregon:

North
Platte,
central
southwestern
Nebraska: