(
Phase
III
3/
07/
06)
Environmental
Fate
and
Ecological
Risk
Assessment
for
the
Reregistration
of
MCPB
and
MCPB
Sodium
for
Use
on
Peas
Marie
Janson,
Environmental
Scientist
Alex
Clem,
Environmental
Scientist
Reviewed
and
Approved
by:
Ed
Odenkirchen,
SeniorScientist
Kevin
Costello,
Acting
Branch
Chief
Environmental
Risk
Branch
I
United
States
Environmental
Protection
Agency
Office
of
Pesticide
Programs
Environmental
Fate
and
Effects
Division
Environmental
Risk
Branch
I
Ariel
Rios
Building
1200
Pennsylvania
Ave.,
NW
Mail
Code
7507C
Washington,
DC
20460
(
Phase
III
3/
07/
06)
i
TABLE
OF
CONTENTS
LIST
OF
TABLES.....................................................................................................................
iii
LIST
OF
FIGURES
...................................................................................................................
iv
I.
EXECUTIVE
SUMMARY...................................................................................................
1
A.
Nature
of
Chemical
Stressor
............................................................................................
1
B.
Potential
Risks
to
Non­
target
Organisms..........................................................................
2
C.
Conclusions
­
Exposure
Characterization.........................................................................
6
D.
Conclusions
­
Effects
Characterization.............................................................................
6
E.
Uncertainties
and
Data
Gaps............................................................................................
7
II.
PROBLEM
FORMULATION
............................................................................................
10
A.
Stressor
Source
and
Distribution....................................................................................
10
1.
Source
and
Intensity.................................................................................................
10
2.
Physical/
Chemical/
Fate
and
Transport
Properties
.....................................................
10
3.
Pesticide
Type,
Class,
Mode
of
Action.....................................................................
14
4.
Overview
of
Pesticide
Usage....................................................................................
15
B.
Receptors
......................................................................................................................
15
1.
Aquatic
Effects
........................................................................................................
15
2.
Terrestrial
Effects
...................................................................................................
15
3.
Ecosystems
at
Risk
..................................................................................................
16
C.
Assessment
Endpoints
...................................................................................................
16
D.
Conceptual
Model
.........................................................................................................
16
1.
Risk
Hypothesis
.......................................................................................................
16
2.
Diagram...................................................................................................................
18
E.
Analysis
Plan
.................................................................................................................
19
1.
Preliminary
Identification
of
Data
Gaps
and
Methods
...............................................
20
2.
Measures
to
Evaluate
Risk
Hypotheses
and
Conceptual
Model
................................
21
III.
ANALYSIS.........................................................................................................................
22
A.
Use
Characterization......................................................................................................
22
B.
Exposure
Characterization.............................................................................................
23
1.
Environmental
Fate
and
Transport
Study
Summaries................................................
23
2.
Measures
of
Aquatic
Exposure.................................................................................
25
3.
Measures
of
Terrestrial
Exposure.............................................................................
27
C.
Ecological
Effects
Characterization................................................................................
28
1.
Aquatic
Effects
Characterization..............................................................................
28
2.
Terrestrial
Effects
Characterization
..........................................................................
33
IV.
RISK
CHARACTERIZATION...........................................................................................
40
A.
Risk
Estimation
­
Integration
of
Exposure
and
Effects
Data
...........................................
40
1.
Non­
target
Aquatic
Animals
and
Plants
....................................................................
40
2.
Non­
target
Terrestrial
Animals
and
Plants
................................................................
42
(
Phase
III
3/
07/
06)
ii
TABLE
OF
CONTENTS
(
CONT.)

B.
Risk
Description
......................................................................................................
47
1.
Risks
to
Aquatic
Organisms
.....................................................................................
47
2.
Risks
to
Terrestrial
Organisms
.................................................................................
47
3.
Review
of
Incident
Data
..........................................................................................
51
4.
Federally
Threatened
and
Endangered
(
Listed)
Species
Concerns
.............................
51
C.
Description
of
Assumptions,
Limitations,
Uncertainties,
Strengths
and
Data
Gaps
...............
58
APPENDIX
A:
Environmental
Fate
Studies
..............................................................................
59
APPENDIX
B:
Aquatic
Exposure
Model
Results
......................................................................
69
APPENDIX
C:
Terrestrial
Bird
and
Mammal
Model
Results
.....................................................
85
APPENDIX
D:
TerrPlant
and
AgDrift
Model
and
Results
.........................................................
92
APPENDIX
E:
Ecological
Effects
Data.....................................................................................
98
APPENDIX
F:
Data
Requirements..........................................................................................
104
APPENDIX
G:
Environmental
Fate
Bibliography....................................................................
108
APPENDIX
H:
Ecotoxicity
Bibliography
................................................................................
110
(
Phase
III
3/
07/
06)
iii
APPENDIX
I:
Locates
Endangered
Species
....................................................................................................................
114
APPENDIX
J:
MCPA/
MCPB
Calculations
Acute
to
Chronic
Ratio
Aquatic
Organisms........
137
(
Phase
III
3/
07/
06)
iv
TABLE
OF
CONTENTS
(
CONT.)

LIST
OF
TABLES
I.
a.
Summary
of
Environmental
Risk
Conclusions
for
Aquatic
Organisms
and
Plants
for
label
use
application
rate
(
1.5
ae).
..................................................................................
3
I.
b.
Summary
of
Environmental
Risk
Conclusions
for
Terrestrial
Organisms
and
Plants
for
label
use
application
rate
(
1.5
ae)
...................................................................................
4
I.
c.
Environmental
Fate
Data
Requirements
...............................................................................
7
I.
d.
Ecological
Toxicity
Data
Requirements...............................................................................
8
II.
a.
Some
Physical­
Chemical
and
Other
Properties
of
MCPB...................................................
13
II.
b.
Some
Physical­
Chemical
and
Other
Properties
of
MCPB
Sodium......................................
14
II.
c.
Use
of
MCPB
and
MCPB
Sodium
on
Peas........................................................................
15
II.
d.
Risk
Presumptions
for
Terrestrial
Animals
(
birds
and
wild
mammals)
................................
19
II.
e.
Risk
Presumptions
for
Aquatic
Animals.............................................................................
19
II.
f.
Risk
Presumptions
for
Terrestrial
and
Semi­
Aquatic
Plants
...............................................
19
II.
g.
Risk
Presumptions
for
Aquatic
Plants
...............................................................................
20
III.
a.
PRZM/
EXAMS
Input
Parameters
for
MCPB....................................................................
26
III.
b.
Estimated
Environmental
Concentrations
(
µ
g
ae/
L)
of
MCPB
+
Metabolites
in
Surface
Water(
PRZM­
EXAMS)
from
All
Uses
for
Ecological
Assessment.
27
III.
c.
Estimated
Environmental
Concentrations
(
ppm
ae)
of
MCPB
Acid
on
Terrestrial
Food
Items
from
Use
on
Peas....................................................................................................
27
III.
d.
Summary
of
Endpoints
for
MCPB
Acute
and
Chronic
Aquatic
Toxicity
Studies
for
RQ
Evaluation
.....................................................................................................................
30
III.
e.
Freshwater
Fish
Acute
Toxicity
for
MCPB
Sodium..........................................................
31
III.
f.
Freshwater
Invertebrate
Acute
Toxicity
for
MCPB
Sodium.
.............................................
31
III.
g.
Non­
target
Aquatic
Plant
Toxicity
for
MCPB
Sodium.
....................................................
33
III.
h.
Avian
Acute
Oral
Toxicity
for
MCPB
Sodium.
................................................................
34
III.
i.
Avian
Acute
Dietary
Studies
for
MCPB
Sodium..............................................................
34
III.
j.
Mammalian
Acute
Toxicity
for
MCPB.............................................................................
35
III.
k.
Mammalian
Chronic
and
Developmental/
Reproductive
Toxicity
for
MCPB
.....................
36
III.
l.
Non­
target
Insects
­
Acute
Contact.
................................................................................
37
III.
m.
Terrestrial
Non­
target
Plant
Toxicity.
..............................................................................
39
IV.
a.
Summarized
Acute
Aquatic
Organism
Risk
Quotients
for
MCPB
Acid
............................
40
IV.
b.
Summarized
Acute
Aquatic
Plant
Risk
Quotients
for
MCPB
Acid
..................................
41
IV.
c.
Summary
of
endpoints
for
MCPB
acute
terrestrial
toxicity
studies
...................................
42
IV.
d.
Avian
Acute
Risk
Quotient
Summary
.............................................................................
43
IV.
e.
Mammalian
Acute
Risk
Quotient
Summary
.....................................................................
44
IV.
f.
Mammalian
Chronic
Risk
Quotient
Summary
..................................................................
45
IVg.
Summarized
Terrestrial
Plant
Risk
Quotients...................................................................
46
IV.
h.
Distance
of
Disposition
of
MCPB
Equivalent
to
Rates
Tested
in
Vegetative
Vigor
Study....................................................................................................
50
IV.
i.
Summarized
Data
from
LOCATES
..................................................................................
58
Data
Requirement
Tables
for
MCPB
..............................................................................
103
(
Phase
III
3/
07/
06)
v
TABLE
OF
CONTENTS
(
CONT.)

LIST
OF
FIGURES
Figure
II.
a.
Chemical
structures
of
MCPB
and
MCPB
sodium..................................................
13
Figure
II.
b.
Conceptual
Model..................................................................................................
18
(
Phase
III
3/
07/
06)
    
1
  
147
I.
EXECUTIVE
SUMMARY
A.
Nature
of
Chemical
Stressor
Use,
Application
Rate,
Mode
of
Action
MCPB
[
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid]
is
an
acidic
phenoxy
herbicide
that
is
currently
registered
only
for
use
on
peas
(
field,
canned,
and
dried)
to
control
or
suppress
Canada
thistle
and
certain
other
broadleaf
weeds.
It
is
applied
when
the
peas
are
tolerant
to
the
herbicide,
which
is
from
the
time
of
shoot
emergence
until
about
three
leaf
nodes
before
flowering
(
typically
6
to
12
nodes).

MCPB
is
formulated
as
its
sodium
salt
(
sometimes
designated
as
MCPB
sodium),
which
can
be
applied
once
annually
through
direct
aerial
or
ground
spray.
The
maximum
application
rate
for
the
salt
is
1.6
lbs/
acre
(
1.79
kg/
ha);
or,
in
terms
of
acid
equivalents
(
ae),
this
rate
converts
to
1.5
lbs/
acre
(
1.68
kg/
ha)
of
MCPB
acid.

Information
from
the
published
literature
(
Dexter
et
al.
1994,
Heimann
and
Neman
1997)
concerning
the
mode
of
action
of
phenoxy
herbicides
indicates
that
they
are
systemic
growth
regulating
hormones
that
act
at
multiple
sites
in
a
plant
to
disrupt
hormone
(
auxin)
balance
and
protein
synthesis.
The
result
is
plant
growth
abnormalities.
Uptake
of
phenoxy
herbicides
is
said
to
be
primarily
through
the
foliage,
but
root
and
seed
uptake
are
also
said
to
occur.

Environmental
Fate
Summary
Based
on
laboratory
studies
and
physicochemical
properties,
MCPB
is
not
volatile,
not
persistent,
and
not
likely
to
bioconcentrate.
Its
acidic/
anionic
nature,
physicochemical
properties,
and
relatively
low
sorption
to
soil
(
average
soil
sorption
coefficient
of
0.85
mL/
g),
indicate
that
MCPB
is
prone
to
leach
and
runoff.
Field
dissipation
studies
are
not
available.

In
addition
to
MCPB,
two
by­
products
of
its
aerobic
soil
metabolism,
although
minor
(<
10%)
in
concentration,
are
also
of
potential
concern
because
of
their
chemical
structural
similarity
to
parent.
These
are:
(
1)
MCPA
[(
4­
chloro­
2­
methylphenoxy)
acetic
acid],
which
is
another
registered
herbicide
of
the
phenoxy
class,
and
(
2)
the
closely
related
CHPA­
hexose
conjugate
[(
4­
chloro­
2­
methylphenoxy)­
2­
 ­
glucopyranoside
acetic
acid].
Chemical
structures
of
these
compounds
are
in
Appendix
A.
In
the
single
aerobic
soil
metabolism
study
available,
these
two
compounds
were
each
detected
at
average
maxima
of
approximately
6­
7%
of
applied
radioactivity
during
the
first
3
to
15
days
of
incubation,
with
both
decreasing
to
less
than
2%
by
the
end
of
a
120­
day
study.
The
only
major
identified
transformation
product
was
carbon
dioxide.

The
MCPA
metabolite,
as
previously
documented
in
its
USEPA
Reregistration
Eligibility
Document
(
dated
September
30,
2004)
and
evidenced
in
fate
studies
of
MCPB,
is
similar
to
MCPB
in
all
available
characteristics.
Although
we
do
not
have
such
information
for
the
CHPA­
hexose
conjugate,
based
on
its
chemical
structure,
it
is
reasonable
to
assume
that
it
also
shares
the
same
general
chemical
profile.
As
it
so
happens,
because
of
their
relatively
minor
presence
and
lack
of
persistence,
whether
we
included
or
excluded
these
two
metabolites
had
little
influence
on
the
overall
risk
assessment.
Their
inclusion
makes
(
Phase
III
3/
07/
06)
    
2
  
147
negligible
difference
in
terrestrial
exposure
and
in
acute
aquatic
exposure.
Excluding
the
two
metabolites
from
the
longest
(
60
day)
chronic
aquatic
exposure
assessment
results
in
a
decrease
in
aquatic
concentration
of
only
approximately
10%,
an
amount
well
within
the
variation
in
natural
processes
and
experimental
error.
Nevertheless,
we
included
both
metabolites
in
combination
with
parent
MCPB
as
total
toxic
residues
with
a
combined
or
overall
half­
life
of
26
days,
and
assumed
toxicities
and
environmental
fate
properties
equivalent
to
parent.

MCPB
was
essentially
stable
to
hydrolysis
(
extrapolated
half­
life
greater
than
500
days
based
on
a
study
lasting
only
30
days),
but
photolyzed
in
laboratory
water
under
optimal
light
exposure
conditions
with
half­
lives
of
approximately
2
to
3
days.
Phototransformation
products
included
4
­(
4­
hydroxy­
o­
tolyloxy)
butyric
acid;
2,4­
dihyroxyphenyl
formate;
ocresol
benzoic
acid;
and
2­
hydroxyphenyl
formate.
Specific
study
information
is
not
available
concerning
the
fate
of
these
products,
and
we
have
not
included
any
potential
effects
of
aqueous
photolysis
products
in
the
risk
assessment.
However,
based
on
their
chemical
structure,
these
are
not
expected
to
be
persistent.
Furthermore,
should
there
be
any
concerns
for
toxicity,
we
can
conclude
that,
either
singly
or
in
summation,
these
products
would
be
in
aquatic
concentrations
below
the
maximum
concentrations
estimated
for
parent.
Additional
exposure
refinements
could
be
pursued,
if
warranted
by
any
toxicological
concerns.

B.
Potential
Risks
to
Non­
target
Organisms
The
risk
assessment
indicates
the
potential
acute
risks
to
non­
target
terrestrial
plants,
birds,
and
mammals.
Also,
this
risk
assessment
indicates
potential
chronic
(
developmental/
reproductive)
risk
to
mammals,
and
potential
risks
to
endangered
species
from
MCPB
usage
on
peas.
Tables
Ia
and
Table
Ib
summarize
risks
and
uncertainties
for
aquatic
and
terrestrial
organisms
and
plants.
No
estuarine
marine
fish
or
invertebrate
data
were
submitted.
Because
peas
may
be
planted
near
estuarine
marine
environments
this
data
would
be
of
significant
value
for
the
evaluation
of
estuarine
marine
organisms.
Potential
chronic
risks
for
aquatic
organisms
cannot
be
evaluated
due
to
lack
of
submitted
data.
Consequently,
it
is
not
possible
to
discount
possible
risks
to
these
organisms
until
further
data
is
submitted.

Table
I.
a.
Summary
of
Environmental
Risk
Conclusions
for
Aquatic
Organisms
and
Plants
for
label
use
application
rate
(
1.5ae/
A)
(
Phase
III
3/
07/
06)
    
3
  
147
Assessment
Endpoint
Summarized
Risk
Characterization
and
Important
Uncertainties
Acute
Risk
to
Freshwater
Fish
No
exceedences
occurred
for
acute
freshwater
fish
,
acute
restricted
use
or
endangered
species
LOCs
for
ground
or
aerial
spray
applications.

Chronic
Risk
to
Freshwater
Fish
No
chronic
freshwater
fish
toxicity
data
were
submitted
for
the
TGAI.
Therefore,
it
is
not
possible
to
discount
possible
chronic
risks
to
freshwater
fish
until
further
data
is
submitted.

Acute
Risk
to
Freshwater
Invertebrates
No
exceedences
occurred
for
acute
freshwater
invertebrates
,
acute
restricted
use
or
endangered
species
LOCs
for
ground
or
aerial
spray
applications.

Chronic
Risk
to
Freshwater
Invertebrates
No
chronic
freshwater
invertebrate
toxicity
data
were
submitted
for
the
TGAI.
Therefore,
it
is
not
possible
to
discount
possible
chronic
risks
freshwater
invertebrates
until
further
data
is
submitted.

Acute
Risk
to
Estuarine/
Marine
Fish
No
acute
estuarine/
marine
fish
toxicity
data
were
submitted
for
the
TGAI.
Therefore,
it
is
not
possible
to
discount
possible
acute
and
endangered
species
risks
estuarine/
marine
fish
until
further
data
is
submitted.

Chronic
Risk
to
Estuarine/
Marine
Fish
No
chronic
estuarine/
marine
fish
toxicity
data
were
submitted
for
the
TGAI.
Therefore,
it
is
not
possible
to
discount
possible
chronic
risks
estuarine/
marine
fish
until
further
data
is
submitted.

Acute
Risk
to
Estuarine/
Marine
Invertebrates
No
acute
estuarine/
marine
invertebrate
data
was
submitted
for
the
TGAI.
Therefore,
it
is
not
possible
to
discount
possible
acute
and
endangered
species
risks
estuarine/
marine
invertebrates
until
further
data
is
submitted.

Chronic
Risk
to
Estuarine/
Marine
Invertebrates
No
chronic
estuarine/
marine
invertebrate
toxicity
data
was
submitted
for
the
TGAI.
Therefore,
it
is
not
possible
to
discount
possible
chronic
risks
estuarine/
marine
fish
until
further
data
is
submitted.

Risk
to
Aquatic
Vascular
Plants
No
exceedences
occurred
for
acute
non­
endangered
aquatic
vascular
plants.
Endangered
vascular
plants
can
not
be
assessed
due
to
non­
discreet
NOEC
value.

Risk
to
Aquatic
Non­
vascular
Plants
No
exceedences
occurred
for
acute
non­
endangered
aquatic
non­
vascular
plants.
(
Phase
III
3/
07/
06)
    
4
  
147
Table
I.
b.
Summary
of
Environmental
Risk
Conclusions
for
Terrestrial
Organisms
and
Plants
for
label
use
application
rate
(
1.5ae/
A)

Assessment
Endpoint
Summarized
Risk
Characterization
and
Important
Uncertainties
Acute
Risk
to
Birds
Acute
risk,
acute
restricted
use
and
endangered
species
LOCs
were
exceeded
for
20
g
and
100g
birds.
Acute
restricted
use
and
endangered
species
LOCs
were
exceeded
for
1000g
birds.

Chronic
Risk
to
Birds
No
chronic
bird
toxicity
data
were
submitted
for
MCPB.
However,
the
chronic
bird
study
from
MCPA
was
substituted
for
MCPB.
No
exceedences
occurred
for
chronic
risk
to
birds.

Acute
Risk
to
Mammals
No
exceedences
occurred
for
acute
or
acute
restricted
use
mammal
LOCs..
Endangered
species
LOCs
were
exceeded
for
15g
and
35g
mammals
Chronic
Risk
to
Mammals
Chronic
risk
LOCs
were
exceeded
in
all
weight
classes(
15g,
35g,
and
1000g)
of
mammals
Terrestrial
Plants
Acute
non­
endangered
and
acute
endangered
species
LOCs
are
exceeded
for
monocots
and
dicots
from
both
aerial
and
ground
applications.

Non­
target
Insects
Based
on
acute
contact
toxicity
studies
on
honeybees,
MCPB
is
classified
as
non­
toxic
to
these
receptors.

The
results
of
this
risk
assessment
indicate
that
MCPB
applied
at
the
maximum
application
rate
according
to
label
directions,
as
a
liquid
spray
for
ground
or
aerial
applications,
will
impact
nontarget
plants
for
some
distance
from
the
application
site.
At
the
label
application
rate
of
1.5
lbs
ae/
acre,
model­
estimated
RQs
exceeded
acute
risk
LOCs
for
non­
target
monocots
and
dicots
located
in
dryland
and
semi­
aquatic
areas
adjacent
to
treated
areas,
both
as
a
result
of
combined
runoff
and
spray
drift,
and
from
spray
drift
alone.
.

Risk
quotients
for
birds
exceed
the
acute
risk
LOC
from
consumption
of
short
grass
(
all
avian
weight
classes),
broadleaf
forage/
small
insects
(
20
g
and
100
g
birds)
and
tall
grass
(
20
g
birds)
feed
items.
Because
these
acute
lethality
risks
were
calculated
based
on
a
laboratory
method
of
dosing
and
not
actual
feeding
habits
in
the
field,
they
represent
a
conservative
estimation
of
risk
The
laboratory
method
is
a
gavage
dose
which
represents
a
very
short­
term
high
intensity
exposure,
whereas
dietary
exposure
may
be
of
a
more
prolonged
nature.
The
dietary
approach
assumes
that
animals
in
the
field
are
consuming
food
at
a
rate
similar
to
that
of
confined
laboratory
animals.
The
strength
of
this
assumption
is
uncertain,
because
energy
content
in
food
items
differs
between
the
field
and
in
the
laboratory,
as
do
the
energy
requirements
of
wild
and
captive
animals.
However,
because
acute
effects
were
observed
in
both
studies,
including
the
dietary
study
at
doses
>
569
ppm
ae,
acute
risks
to
avian
species
using
the
treated
fields
or
inhabiting
adjacent
edge
or
riparian
communities
could
result
from
the
labeled
use
of
MCPB.

Assuming
maximum
and
mean
residue
levels
at
the
maximum
application
rate,
chronic
risk
LOCs
were
exceeded
in
all
weight
classes
(
15
g,
35
g,
and
1000g)
of
mammals
for
consumption
of
short
grass,
tall
grass
and
broadleaf
forage/
small
insects.
Assuming
maximum
residue
levels
at
the
maximum
application
rate,
chronic
risk
LOCs
were
exceeded
in
15
g
and
35g
mammals
for
consumption
of
fruit
and
large
insects.
However,
because
the
chronic
LOCs
are
exceeded
for
multiple
food
categories,
potential
exposure
may
still
be
high
enough
to
warrant
concern.
Based
(
Phase
III
3/
07/
06)
    
5
  
147
on
effects
seen
in
the
chronic
mammalian
toxicity
studies,
MCPB
may
be
classified
as
a
potential
endocrine
disruptor.
When
the
appropriate
screening
and/
or
testing
protocols
being
considered
under
the
Agency's
Endocrine
Disruptor
Screening
Program
have
been
developed,
MCPB
may
be
subjected
to
additional
screening
and/
or
testing
to
better
characterize
effects
related
to
endocrine
disruption.

The
preliminary
risk
assessment
for
endangered
species
indicates
that
MCPB
exceeds
the
endangered
species
LOCs
for
the
single
application
per
year
for
peas
grown
with
an
application
rate
of
1.5
lbs
ae/
acre
for
the
following
taxonomic
groups:

·
small
20g,
medium
100g
and
large
1000
g
birds
feeding
on
short
grass,
tall
grass,
and
broadleaf
forage/
small
insects;
small
birds
feeding
on
fruits
pods
seeds,
and
large
insects
·
small
15g
and
medium
35g
mammals
feeding
on
short
grass;
small
mammals
(
15
g)
feeding
on
broadleaf
forage/
small
insects.

·
non­
target
terrestrial
plants
­
monocots
and
dicots
adjacent
to
treated
areas
and
semi­
aquatic.

Information
from
LOCATES
indicates
that
several
species
of
birds,
mammals
and
plants
are
potentially
affected
by
use
of
MCPB
on
peas.

Exposure
to
MCPB
results
in
direct
effects
to
plant
species
that
could
result
in
effects
at
the
higher
levels
of
organization
(
i.
e.
population,
trophic
level,
community,
ecosystem).
Consequently,
there
may
be
a
concern
for
potential
indirect
effects
to
listed
species
dependent
upon
birds
that
consume
feed
items
contaminated
with
MCPB
residues,
such
as
predatory
birds
and
mammals.
The
guideline
terrestrial
plant
studies
indicate
direct
adverse
effects
to
seedling
emergence
as
well
as
non­
lethal
effects
including
brown
leaf
tips,
necrosis,
chlorosis,
stem
tumors,
leaf
curl,
and
decrease
in
size.
In
the
guideline
aquatic
vascular
plant
studies,
concentrations
as
low
as
0.16
mg
ae/
L
resulted
in
chlorosis,
curling,
and
decreased
root
formation
in
the
plant.
In
terrestrial
and
shallow­
water
aquatic
communities,
plants
are
the
primary
producers
upon
which
the
succeeding
trophic
levels
depend.
If
the
available
plant
material
is
impacted
due
to
the
effects
of
MCPB,
this
may
have
negative
effects
not
only
on
the
herbivores,
but
throughout
the
food
chain.
Also,
depending
on
the
severity
of
impacts
to
the
plant
communities
(
edge
and
riparian
vegetation),
community
assemblages
and
ecosystem
stability
may
be
altered
(
i.
e.
reduced
bird
populations
in
edge
habitats;
reduced
riparian
vegetation
resulting
in
increased
light
penetration
and
temperature
in
aquatic
habitats).
Furthermore,
reduction
of
upstream
riparian
vegetation
that
would
otherwise
supply
downstream
habitats
could
result
not
only
in
a
loss
of
a
significant
component
of
food
for
aquatic
herbivores
and
detritivores,
but
also
of
habitat
(
i.
e.
leaf
packs,
materials
for
case­
building
for
invertebrates).
This
assessment
of
risk
to
aquatic
receptors
provides
toxicity
data
on
freshwater
systems
only
due
to
lack
of
submitted
estuarine/
marine
toxicity
data.

The
risk
assessment
indicates
that
there
are
no
acute
risks
to
fish,
fresh
water
aquatic
invertebrates,
algae
or
mammals.
There
were
no
exceedances
of
the
aquatic
Acute
Risk,
Acute
Restricted
Use,
and
Endangered
Species
LOCs
for
freshwater
fish
and
aquatic
invertebrates.
There
were
also
no
exceedances
of
the
non­
endangered
Acute
Risk
LOC
for
aquatic
algae
and
vascular
plants.
(
Phase
III
3/
07/
06)
    
6
  
147
Consequently,
freshwater
fish,
freshwater
invertebrates,
algae
and
vascular
plants
inhabiting
surface
waters
adjacent
to
an
MCPB
treated
field
would
not
be
at
risk
for
adverse
acute
effects
to
growth
and
survival
when
exposed
to
residues
in
surface
runoff
and
spray
drift
as
a
result
of
ground
and/
or
aerial
spray
application.
Acute
Risk
LOCs
were
not
exceeded
for
mammals
consuming
short
grass,
tall
grass,
broadleaf
forage
and
small
insects,
fruit
and
large
insects,
or
seeds
and
pods
with
maximum
or
mean
residue
levels.
EFED
currently
does
not
quantify
risks
to
terrestrial
non­
target
insects.

C.
Conclusions
­
Exposure
Characterization
Routes
of
exposure
evaluated
in
this
risk
assessment
focused
on
deposition,
runoff
and
spray
drift
from
ground
and
aerial
spray
applications
of
MCPB
for
peas.
Based
on
the
physical
and
chemical
properties
as
well
as
the
laboratory
fate
studies,
MCPB
will
predominately
exist
in
the
ionic
or
salt
form
at
ambient
environmental
pHs.
In
addition,
the
only
registered
formulation
for
field
application
is
the
MCPB
sodium
salt.
MCPB
salt
is
highly
soluble
(
200,000
mg/
L)
in
water
and
mobile
in
aqueous
environmental
systems.
MCPB
degrades
rapidly
via
photolysis
(
half­
life
of
2.6
days)
and
is
readily
biodegraded
in
aerobic
and
anaerobic
soils;
thus
long
term
persistence
in
soils
is
not
likely.
The
low
octanol­
water
partition
coefficient
(
1.33)
indicates
that
MCPB
would
have
a
low
tendency
to
bioaccumulate.
In
addition,
based
on
its
tendency
not
to
persist
in
the
environment
and
the
single
application
per
year,
long­
term
persistence
in
the
environment
is
not
likely.
No
information
is
available
on
aquatic
biodegradation
of
MCPB.

A
review
of
ground
water
and
surface
water
monitoring
data
indicated
no
detection
of
MCPB
and
there
were
no
reported
incidents
from
MCPB
usage.

D.
Conclusions
­
Effects
Characterization
Available
acute
toxicity
data
indicate
that
MCPB
sodium
is
moderately
toxic
to
rainbow
trout
and
slightly
toxic
to
bluegill
sunfish
and
daphnids.
No
toxicity
studies
have
been
conducted
to
determine
potential
chronic
effects
to
fish
and
aquatic
invertebrates.
Laboratory
studies
indicate
that
MCPB
is
toxic
to
algae
and
aquatic
vascular
plant
species,
based
on
observed
adverse
effects
on
growth
and
development.

Available
acute
toxicity
data
indicate
that
MCPB
sodium
is
practically
non­
toxic
to
bobwhite
quail
and
mallard
ducks
in
the
diet.
However,
an
oral
gavage
study
with
bobwhite
quail
indicates
that
MCPB
sodium
was
moderately
toxic.
MCPB
is
classified
as
practically
non­
toxic
to
small
mammals
on
an
acute
oral
basis.
However,
a
13­
week
chronic
oral
study
in
dogs
reported
reproductive
effects,
including
testicular
and
prostate
atrophy
and
curtailment
of
spermatogenic
activity.
In
developmental
studies
with
rats
and
rabbits,
maternal
toxicity
was
observed
at
doses
ranging
from
20
­
100
mg/
kg/
day
(
NOAEL
rabbit
=
5
mg
ai/
kg/
day;
4.55
mg
ae/
kg/
day)
and
developmental
effects
were
observed
in
rats
at
a
dose
of
100
mg/
kg/
day.
An
acute
contact
study
indicates
that
MCPB
sodium
is
relatively
non­
toxic
to
honey
bees.
No
toxicity
studies
have
been
conducted
to
determine
the
effect
of
residues
to
pollinators.
An
MCPA
chronic
bird
study
was
substituted
for
MCPB
which
resulted
in
a
NOAEC
of
1000
mg/
kg­
diet.

Terrestrial
plant
toxicity
studies
indicate
that
MCPB
sodium
negatively
impacts
seedling
emergence
and
vegetative
vigor
in
monocots
and
dicots.
Non­
lethal
effects
included
brown
leaf
(
Phase
III
3/
07/
06)
    
7
  
147
tips,
necrosis,
decrease
in
size,
leaf
curling,
chlorosis,
and
stem
tumors.
Consequently,
exposure
to
MCPB
presents
a
potential
risk
to
non­
target
plants
inhabiting
edge
habitats
adjacent
to
target
fields
and
riparian
vegetation
along
streams
and/
or
ponds
in
close
proximity
to
sprayed
fields.

E.
Uncertainties
and
Data
Gaps
There
are
a
few
areas
of
uncertainty
in
the
terrestrial
and
the
aquatic
organism
risk
assessments
that
could
potentially
cause
an
underestimation
of
risk.
First,
MCPB
chronic
toxicity
data
for
aquatic
organisms
are
not
available.
MCPB
acute
toxicity
data
for
estuarine
marine
fish
and
invertebrates
are
not
available;
thus
the
potential
risk
to
estuarine
marine
fish
and
estuarine
marine
invertebrates
cannot
be
precluded.
Because
the
potential
for
risk
to
these
taxa
cannot
be
evaluated,
this
risk
assessment
should
be
considered
incomplete.

Additional
uncertainty
results
from
the
lack
of
information
and/
or
data
in
several
components
of
this
ecological
risk
assessment.
For
instance,
this
assessment
accounts
only
for
exposure
of
nontarget
organisms
to
MCPB,
but
not
to
its
degradates.
Data
are
not
available
concerning
the
fate
and
toxicity
of
the
photolytic
degradation
products
of
MCPB.
MCPA
is
a
product
of
anaerobic
biodegradation
in
soil
and
this
assessment
provides
available
toxicity
data
for
MCPA
that
indicates
that
the
toxicity
of
MCPA
acid
is
very
similar
to
that
of
MCPB
(
Reregistration
Eligibility
Decision
for
MCPA,
2004).

Tables
I.
c.
and
I.
d.
summarize
data
gaps
and
environmental
fate
and
ecological
toxicity
data
requirements
submitted
respectively.

TABLE
I.
c.
of
Environmental
Fate
Data
Requirements
Guideline
#
Data
Requirement
MRID
#
Study
Classification
Is
more
data
needed?

161­
1
Hydrolysis
42574301
Acceptable
no
161­
2
Photodegradation
in
Water
42574302
Acceptable
no
161­
3
Photodegradation
on
Soil
43829901
Invalid
no
161­
4
Photodegradation
in
Air
N/
A
no
162­
1
Aerobic
Soil
Metabolism
43247601
Acceptable
no
162­
2
Anaerobic
Soil
Metabolism
43015501
Acceptable
no
162­
3
Anaerobic
Aquatic
Metabolism
No
study
submitted
no
162­
4
Aerobic
Aquatic
Metabolism
No
study
submitted
(
not
at
this
time)

163­
1
Leaching­
Adsorption/
Desorption
42693701
43466401
Acceptable
no
163­
2
Laboratory
Volatility
N/
A
163­
3
Field
Volatility
N/
A
164­
1
Terrestrial
Field
Dissipation
No
study
submitted
yes
164­
2
Aquatic
Field
Dissipation
N/
A
164­
3
Forestry
Dissipation
N/
A
(
Phase
III
3/
07/
06)
    
8
  
147
TABLE
I.
c.
of
Environmental
Fate
Data
Requirements
Guideline
#
Data
Requirement
MRID
#
Study
Classification
Is
more
data
needed?

165­
4
Accumulation
in
Fish
N/
A
165­
5
Accumulation­
aquatic
nontarget
N/
A
166­
1
Ground
Water­
small
prospective
N/
A
166­
2
Groundwater
­
small
retrospective
N/
A
201­
1
Droplet
Size
Spectrum
N/
A
202­
1
Drift
Field
Evaluation
N/
A
TABLE
I.
d.
of
Ecological
Toxicity
Data
Requirements
Guideline
#
Data
Requirement
MRID
#
Classification
Is
more
data
needed?

71­
1
Avian
acute
oral
LD50
(
bobwhite
quail)
42560801
Acceptable
No
71­
2
Avian
acute
dietary
LC50
(
bobwhite
quail)
(
mallard
duck)
42560802
42560803
Acceptable
Acceptable
No
71­
4
Avian
reproduction
(
bobwhite
quail)
(
mallard
duck)
43505201
MCPA
Acceptable
No
72­
1
Freshwater
fish
acute
LC500
(
rainbow
trout)
(
bluegill
sunfish)
42532608
42532601
Acceptable
Acceptable
No
72­
2
Freshwater
invertebrate
acute
EC50
(
daphnia)
42532602
Acceptable
No
72­
3a
Estuarine/
marine
fish
acute
LC50
(
sheepshead
minnow)
N/
A
Yes
72­
3b
Estuarine/
marine
invertebrate
acute
EC50
(
eastern
oyster)
N/
A
Yes
72­
4a
Estuarine
marine
fish
early
life
stage
N/
A
reserved
72­
4a
Freshwater
fish
early
life
stage
(
fathead
minnow)
N/
A
Yes
72­
4b
Freshwater
invertebrate
life
cycle
(
daphnia)
N/
A
Yes
72­
4d
Estuarine/
marine
life
cycle
(
mysid)
N/
A
reserved
72­
5
Freshwater
fish
full
life
cycle
N/
A
reserved
72­
7
Aquatic
Field
Study
N/
A
No
81­
1
Acute
mammalian
oral
LD50
(
rat)
144801
Acceptable
No
(
Phase
III
3/
07/
06)
    
9
  
147
82­
1(
a)
82­
1(
b)
Mammalian
chronic
(
dog)
(
rat)

116345
116344
Acceptable­
minimum
Acceptable
­
minimum
No
83­
3
Mammalian
Developmental
(
rat)
(
rabbit)
40865401
40865402
Acceptable
Acceptable
No
83­
4
MCPB
Mammalian
Reproduction
N/
A
Yes
83­
4
MPCA
Mammalian
Reproduction
40041701
Acceptable
No
123­
1(
a)
Seedling
Emergence
­
Tier
II
42560804
Acceptable
No
122­
1(
b)
Vegetative
Vigor
­
Tier
I
42560804
Acceptable
No
123­
1(
b)
Vegetative
Vigor
­
Tier
II
42560804
Acceptable
No
122­
2
Aquatic
plant
algae
(
green
algae)
(
blue­
green
algae)
(
diatom)
(
marine
diatom)
42532605
42532603
42532609
42532606
Acceptable
Acceptable
Acceptable
Acceptable
No
123­
2
Aquatic
plant
acute
EC50
(
duckweed)
42532604
Acceptable
No
141­
1
Acute
honey
bee
contact
LD50
42532607
Acceptable
No
141­
2
Honey
Bee
Residue
on
Foliage
N/
A
Yes
141­
5
Honey
Bee
Field
Testing
for
Pollinator
N/
A
Yes
(
Phase
III
3/
07/
06)
    
10
  
147
II.
PROBLEM
FORMULATION
The
purpose
of
the
ecological
risk
assessment
(
ERA)
is
to
evaluate
and
address
ecological
risks
associated
with
the
reregistration
of
the
herbicide
MCPB
[
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid]
for
use
on
peas;
including
field,
canned
and
dried
peas.
The
current
registration
allows
nationwide
use
on
peas
to
control
Canada
thistle
and
other
broadleaf
weeds.

A.
Stressor
Source
and
Distribution
1.
Source
and
Intensity:
MCPB
is
a
phenoxy
herbicide
that
is
currently
registered
for
use
on
peas
(
field,
canned,
and
dried)
to
control
or
suppress
Canada
thistle
and
certain
other
broadleaf
weeds.
It
is
formulated
only
as
its
sodium
salt
(
MCPB
sodium).
It
is
applied
once
annually
through
direct
aerial
(
fine­
medium
and
coarse
spray)
or
ground
spray
application
at
a
maximum
rate
of
1.6
lbs
ai/
acre
(
1.5
pounds
acid
equivalent
per
acre).
Exposure
to
MCPB
can
occur
by
ground
deposition,
indirect
spray
drift,
and
surface
water
runoff.

2.
Physical/
Chemical/
Fate
and
Transport
Properties:
A
summary
of
selected
physical
and
chemical
properties
for
MCPB
and
MCPB
sodium
are
presented
below
in
Tables
II.
a
and
b,
respectively.
Section
III.
B.
1
and
Appendix
A
have
more
detail
on
specific
environmental
fate
studies.

Only
laboratory
environmental
fate
studies
are
available
for
MCPB.
Field
dissipation
studies
are
not
available.
No
study
data
(
laboratory
or
field)
are
available
for
biodegradation
in
water
(
aerobic
or
anaerobic
aquatic
metabolism).
In
the
absence
of
aquatic
biodegradation
data,
for
simulation
modeling
purposes
EFED
substitutes
soil
metabolism
data
with
adjustment
factors
to
allow
for
natural
substrate
variation.

As
can
be
seen
from
Tables
IIa
and
IIb,
MCPB
is
an
acidic
compound
(
pKa
values
of
4.6
and
4.8).
(
This
acid
strength
is
comparable
to
that
for
acetic
acid,
which
is
the
essential
component
present
at
a
concentration
of
5%
in
vinegar.)
Because
of
its
acidity,
MCPB
will
exist
predominately
in
the
ionic
(
anionic)
or
salt
form
at
typical
environmental
pHs.
The
calculated
degree
of
ionization
corresponding
to
MCPB's
acid
strength
is
greater
than
99%
at
pH
7,
and
ranges
from
approximately
70%
to
99.99+%
from
pH
5
to
9,
respectively.
In
all
formulations
registered
for
field
application,
MCPB
is
added
as
its
sodium
salt,
which
has
a
solubility
in
water
of
approximately
200,000
mg/
L
(
200
g/
L).

The
relatively
low
Henry's
Law
Constant
and
vapor
pressure
for
MCPB
and
collateral
evidence
showing
its
absence
in
traps
for
volatile
organic
compounds
in
various
laboratory
studies
indicate
that
it
is
non­
volatile.

Based
on
laboratory
studies,
MCPB
biodegrades
in
soil.
In
the
only
soil
tested
for
aerobic
metabolism,
MCPB
had
a
half­
life
of
approximately
18
days.
The
major
identified
transformation
product
was
carbon
dioxide.
Two
by­
products
of
aerobic
soil
metabolism,
(
Phase
III
3/
07/
06)
    
11
  
147
although
minor
(<
10%)
in
concentration,
are
also
of
potential
concern
because
of
their
chemical
structural
similarity
to
parent.
These
are:
(
1)
MCPA
[(
4­
chloro­
2­
methylphenoxy)
acetic
acid],
which
is
another
registered
herbicide
of
the
phenoxy
class,
and
(
2)
the
closely
related
CHPA­
hexose
conjugate
[(
4­
chloro­
2­
methylphenoxy)­
2­
 ­
glucopyranoside
acetic
acid].
Chemical
structures
of
these
compounds
are
in
Appendix
A.
In
the
single
aerobic
soil
metabolism
study
available,
these
two
compounds
were
each
detected
at
average
maxima
of
approximately
6­
7%
of
applied
radioactivity
during
the
first
3
to
15
days
of
incubation,
with
both
decreasing
to
less
than
2%
by
the
end
of
a
120­
day
study.

The
MCPA
metabolite,
as
previously
documented
in
its
USEPA
Reregistration
Eligibility
Document
(
dated
September
30,
2004)
and
evidenced
in
fate
studies
of
MCPB,
is
similar
to
MCPB
in
all
available
characteristics.
Although
we
do
not
have
such
information
for
the
CHPA­
hexose
conjugate,
based
on
its
chemical
structure,
it
is
reasonable
to
assume
that
it
also
shares
the
same
general
chemical
profile.
As
it
so
happens,
because
of
their
relatively
minor
presence
and
lack
of
persistence,
whether
we
included
or
excluded
these
two
metabolites
had
little
influence
on
the
overall
risk
assessment.
Their
inclusion
makes
negligible
difference
in
terrestrial
exposure
and
in
acute
aquatic
exposure.
Excluding
the
two
metabolites
from
the
longest
(
60
day)
chronic
aquatic
exposure
assessment
results
in
a
decrease
in
aquatic
concentration
of
only
approximately
10%,
an
amount
well
within
the
variation
in
natural
processes
and
experimental
error.
Nevertheless,
we
included
both
metabolites
in
combination
with
parent
MCPB
as
total
toxic
residues
with
a
combined
or
overall
half­
life
of
26
days,
and
assumed
toxicities
and
environmental
fate
properties
equivalent
to
parent.
(
For
modeling
purposes,
in
order
to
allow
for
natural
variation
in
the
microbiological
activity
of
soils,
EFED
uses
three
times
a
single
soil
value
as
a
reasonable
upper
confidence
bound
for
an
average
halflife
which
in
this
case
is
approximately
78
days).

In
the
only
soil
tested
for
anaerobic
metabolism,
MCPB
had
a
system
half­
life
of
approximately
11
days.
(
Again,
for
modeling
purposes,
in
order
to
allow
for
natural
variation
in
microbiological
activity
of
soils,
EFED
uses
three
times
a
single
soil
value
as
a
reasonable
upper
confidence
bound
for
an
average
half­
life,
which
in
this
case
is
approximately
34
days.)
The
major
transformation
product
in
the
aerobic
phase
of
this
anaerobic
soil
metabolism
study
was
again
MCPA
[(
4­
chloro­
2­
methylphenoxy)
acetic
acid].
Within
experimental
error,
this
product
did
not
appear
to
form
during
the
anaerobic
phase.

MCPB
was
essentially
stable
to
hydrolysis
(
extrapolated
half­
life
greater
than
500
days
based
on
a
study
lasting
only
30
days),
but
photolyzed
in
laboratory
water
under
optimal
light
exposure
conditions
with
half­
lives
of
approximately
2
to
3
days.
[
When
input
directly
into
current
EFED
aquatic
models,
these
photolysis
half­
lives
translate
into
effective
half­
lives
approximately
124
times
longer
(
250
to
400
days)
based
on
scenario
water
depths,
clarity,
and
other
factors.]
Phototransformation
products
included
4
­(
4­
hydroxy­
o­
tolyloxy)
butyric
acid;
2,4­
dihyroxyphenyl
formate;
o­
cresol;
benzoic
acid;
and
2­
hydroxyphenyl
formate.
Specific
study
information
is
not
available
concerning
the
fate
of
these
products,
and
we
have
not
included
any
potential
effects
of
aqueous
photolysis
products
in
the
risk
assessment.
However,
based
on
their
chemical
structure,
these
are
not
expected
to
be
persistent.
Furthermore,
should
there
be
any
concerns
for
toxicity,
we
can
conclude
that,
either
singly
or
in
summation,
these
products
would
be
in
aquatic
concentrations
below
the
maximum
concentrations
estimated
for
parent.
Additional
exposure
refinements
could
be
pursued,
if
warranted
by
any
toxicological
(
Phase
III
3/
07/
06)
    
12
  
147
concerns.

Adsorption/
desorption
(
batch
equilibrium)
of
MCPB
in
four
soils
and
one
sediment
indicate
that
MCPB
is
mobile.
Mean
adsorption
coefficients
(
Kads)
measured
for
each
of
the
soils
were
1.69,
0.26,
0.65,
and
0.78
mL/
g
(
median
of
0.72,
average
of
0.85
mL/
g);
respective
textures
of
these
soils
were
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam.
The
sediment
was
a
sandy
loam
(
pH
of
5.95
and
2.85%
organic
carbon)
for
which
the
mean
Kads
was
10.58
mL/
g.
Adsorption
coefficients
normalized
for
organic
carbon
(
K
oc
)
were
129.57,
47.91,
85.54,
31.27,
and
371.17
mL/
g
organic
carbon
for
the
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam
soils
and
sandy
loam
sediment,
respectively
(
average
K
oc
for
the
five
values
of
130
mL/
g
organic
carbon,
median
of
86
mL/
g
organic
carbon).
The
study
was
not
consistent
with
guidelines
in
that
the
soils
used
in
the
study
were
not
the
same
as
those
used
in
the
aerobic
soil
metabolism
studies.

Based
on
its
acid
nature
and
consistent
correlations
among
relatively
high
solubility,
relatively
low
octanol­
to­
water
partitioning
ratio
(
1.33
at
pH
7),
and
relatively
low
sorption
to
soil,
MCPB
would
be
prone
to
leach
to
ground
water
and
runoff
to
surface
water.
Judging
from
these
factors
and
its
lack
of
persistence
in
soil,
bioconcentration
of
MCPB
is
not
expected.
Figure
II.
a.
Chemical
structures
of
MCPB
and
MCPB
sodium
MCPB
MCPB
Sodium
(
Phase
III
3/
07/
06)
    
13
  
147
TABLE
II.
a.
Some
Physical­
Chemical
and
Other
Properties
of
MCPB.

CAS
Name
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
IUPAC
Name
4
­(
4­
chloro­
o­
tolyloxy)
butyric
acid
CAS
No
94­
81­
5
PC
Code
019201
Empirical
Formula
C11H13ClO3
Molecular
Weight
228.6
Common
Name
MCPB
Formulated
Product
Thristrol
Pesticide
Type
Herbicide
Chemical
Family
Phenoxy
Color/
Form
Brown
flakes;
white
crystalline
solid
(
purified
technical
­
99.5%
pure)

Odor
Slightly
phenolic
Melting
Point
101.5
­
103.0
°
C
Flash
Point
Not
flammable
Relative
Density
1.26
g/
ml
(
at
20
°
C)

Water
Solubility
(
at
20
°
C)
60.4
mg/
L
(
purified
technical
substance
in
purified
water)
29.9
mg/
L
at
pH
4
3.83
mg/
L
at
pH
7
>
250
g/
L
at
pH
10
(
Podall
2002)

Solubility
in
other
solvents
n­
Heptane
0.414
g/
L
at
20
°
C;
Xylene
37.6
g/
L
at
20
°
C
dichloromethane
69.9
g/
L
at
20
°
C;
Methanol
>
250
g/
L
at
20
°
C
n­
Octanol
71.6g/
L
at
20
°
C;
Acetone
>
250
g/
L
at
20
°
C
Ethyl
acetate
144
g/
L
at
20
°
C
(
Podall
2002)

Vapor
Pressure
4.0
x10­
7
torr
(
for
purified
technical
at
25
°
C)
(
Podall
2002)

Henry's
Law
Constant
3.42
x
10­
9
atm
x
m3/
mol;
estimated
at
25
°
C
(
Howard
and
Meylan,
1997)

pKa
4.6
at
20
°
C
(
Podall
2002)

log
Pow
1.33
(
at
pH
7
and
20
°
C)
3.45
(
at
pH
4
and
20
°
C)
­
0.21
(
at
pH
10
and
20
°
C)
(
Podall
2002)

Redraw
to
be
configuration
shown
for
MCPB;
move
Na
to
end
of
carboxyl
group;
show
Na
with
positive
charge
and
COO
with
negative
charge.
(
Phase
III
3/
07/
06)
    
14
  
147
TABLE
II.
b.
Some
Physical­
Chemical
and
Other
Properties
of
MCPB
Sodium.

CAS
Name
Sodium
4­(
2­
methyl­
4­
chlorophenoxy)
butyrate
IUPAC
Name
N/
A
CAS
No
6062­
26­
6
PC
Code
019202
Empirical
Formula
C11H12ClNaO3
Molecular
Weight
250.65677
Common
Name
MCPB
sodium
salt
Formulated
Product
Thristrol
Pesticide
Type
Herbicide
Chemical
Family
Phenoxy
Color/
Form
Colorless
liquid
with
phenolic
odor
Odor
Slightly
phenolic
Melting
Point
N/
A
Flash
Point
Not
flammable
Relative
Density
N/
A
Water
Solubility
200,000
mg/
L
@
25
°
C
(
WSSA
1994)

Solubility
in
other
solvents
(
g/
L
at
20
°
C)
N/
A
3.
Pesticide
Type,
Class,
Mode
of
Action:
MCPB
is
a
phenoxy
herbicide
that
is
used
for
control
of
broadleaf
weeds.
Information
from
the
published
literature
(
NDSU
1994,
Heimann
and
Neman
1997)
concerning
the
mode
of
action
of
phenoxy
herbicides
indicates
that
they
are
systemic
growth
regulating
hormones
that
act
at
multiple
sites
in
a
plant
to
disrupt
hormone
(
auxin)
balance
and
protein
synthesis,
resulting
in
plant
growth
abnormalities.
Cell
division
is
affected
and
can
result
in
changes
in
cell
size
and
shape
and
the
cessation
of
tissue
growth.
Uptake
of
phenoxy
herbicides
is
primarily
through
the
foliage
but
root
and
seed
uptake
can
also
occur.
It
is
then
translocated
to
areas
of
new
plant
growth
by
the
xylem
and
phloem..

Damage
may
include
petiole
twisting
(
epinasty),
fused
petioles
(
trumpeting),
crinkling
and
cupping
of
leaf
margins,
thickening
and
flattening
of
stems
(
fasciation),
and
proliferation
and
distortion
of
roots
and
flowering
parts.
Roots
may
lose
the
ability
to
take
up
soil
nutrients
and
the
xylem
and
phloem
in
stems
may
not
be
able
to
transport
nutrients
throughout
the
plant.
The
extent
of
damage
is
dependent
upon
the
concentration
and
duration
of
exposure.
Nontarget
plants
that
do
not
receive
a
lethal
dose
may
continue
to
grow
normally
beyond
the
affected
parts
unless
tissue
damage
occurs
while
the
plant
is
immature,
thus
retarding
terminal
growth.
Phenoxy
herbicides
are
also
known
to
affect
photosynthesis
and
root
absorption.
Examples
of
sensitive
or
susceptible
plants
include
cotton,
tomatoes,
grapes,
corn,
soybeans,
sugarbeets,
sugarcane,
and
ornamentals.
(
Phase
III
3/
07/
06)
    
15
  
147
4.
Overview
of
Pesticide
Usage:
MCPB
sodium
salt
is
currently
registered
for
use
on
peas
(
including
field,
canned,
and
dried),
and
no
other
agricultural
crop.
It
is
used
postemergent
primarily
to
suppress
Canada
thistle
bud
formation.
MCPB
is
applied
when
the
peas
are
tolerant
to
the
herbicide,
from
shoot
emergence
until
about
three
leaf
nodes
before
flowering
(
typically
6
to
12
nodes).
Canada
thistle
reduces
pea
yields
through
competition
and
presents
problems
during
harvesting.
The
buds
are
difficult
to
remove
from
the
harvested
crop
resulting
in
loss
of
crop
quality
and
profit
to
the
grower.
During
the
canning
and/
or
freeze
processing
of
peas,
the
unopened
Canada
thistle
buds
contaminate
the
product.
Other
target
pests
include
buttercup,
mustard,
lambsquarters,
purslane,
ragweed,
smartweed,
and
pigweed.
Table
II.
c.
summarizes
the
application
rates
from
the
various
product
labels
for
all
proposed
applications.

TABLE
II.
c.
Use
of
MCPB
and
MCPB
Sodium
on
Peas.

Crop
Product
Appl.
Rate
(
lb
ai/
A)
Appl.
Rate
(
lb
ae/
A)
Max
#
Appl/
Yr
Application
Methods
Peas
Thistrol
®
Herbicide
1.6
1.5
1
Spray/
ground
and
aerial
Peas
Sodium
MCPB
Solution
1.6
1.5
1
Spray/
ground
and
aerial
There
are
two
registered
products:
Thistrol
®
Herbicide
(
71368­
5)
and
Sodium
MCPB
Solution
(
71368­
7).
The
registrants
include
A.
H.
Marks
and
Company
Ltd.,
Nufarm
BV
and
Nufarm,
Inc.
The
product
label
for
Thistrol
®
lists
the
active
ingredient
(
23.5%)
as
sodium
salt
of
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
and
76.5%
inert
ingredients
(
not
provided).

B.
Receptors
1.
Aquatic
Effects:
The
emphasis
of
the
risk
assessment
is
to
address
risk
to
non­
target
aquatic
species
that
may
be
exposed
to
residual
MCPB
and
MCPB
sodium.
Spray
drift
and
runoff
to
adjacent
bodies
of
water
are
the
most
likely
sources
of
MCPB
and
MCPB
sodium
exposure
to
nontarget
aquatic
organisms,
including
endangered
and
threatened
species.
Aquatic
organisms
downstream
from
application
areas
could
also
potentially
be
exposed.

2.
Terrestrial
Effects:
Ground
deposition
and
spray
drift
with
resulting
residues
on
animal
feed
items
are
the
most
likely
sources
of
MCPB
and
MCPB
sodium
exposure
to
nontarget
terrestrial
organisms,
including
endangered
and
threatened
species.
Additional
sources
of
exposure
to
MCPB
sodium
could
be
from
water
drunk
from
puddles
in
treated
fields,
ingested
from
feathers
or
fur
through
preening
or
grooming
or
from
inhalation
at
the
time
of
spraying.
However,
this
screening
assessment
only
estimates
potential
dietary
exposure.

Spray
drift
and
runoff
from
treated
fields
present
a
potential
exposure
route
for
non­
target
plants
in
edge
habitats
adjacent
to
target
fields
and
riparian
vegetation
along
streams
and/
or
ponds
in
close
proximity
to
sprayed
fields.

3.
Ecosystems
at
Risk:
Because
peas
can
be
grown
throughout
the
country,
a
variety
of
ecosystems
may
be
exposed.
The
crop
profile
for
Maryland
peas
indicates
that
peas
are
grown
in
estuarine
watershed.
Other
crop
profiles
such
as
Delaware
suggest
that
MCPB
may
be
used
in
(
Phase
III
3/
07/
06)
    
16
  
147
estuarine
as
well
as
freshwater
environments.
In
terrestrial
and
shallow­
water
aquatic
communities,
plants
are
the
primary
producers
upon
which
the
succeeding
trophic
levels
depend.
If
the
available
plant
material
is
impacted
due
to
the
effects
of
MCPB
and
MCPB
sodium,
this
may
have
negative
effects
not
only
on
the
herbivores,
but
throughout
the
food
chain.
Also,
depending
on
the
severity
of
impacts
to
the
plant
communities
(
i.
e.,
edge
habitats,
algal
biomass,
riparian
vegetation),
community
assemblages
and
ecosystem
stability
may
be
altered
(
i.
e.
reduced
bird
populations
in
edge
habitats;
reduced
riparian
vegetation
resulting
in
increased
light
penetration
and
temperature
in
aquatic
habitats).
Furthermore,
reduction
of
upstream
riparian
vegetation
that
would
otherwise
supply
downstream
habitats
could
result
not
only
in
a
loss
of
a
significant
component
of
food
for
aquatic
herbivores
and
detritivores,
but
also
of
habitat
(
i.
e.
leaf
packs,
materials
for
case­
building
for
invertebrates).

C.
Assessment
Endpoints
The
major
assessment
endpoints
related
to
aquatic
environments
are:

(
a).
Direct
effects
to
survival,
reproduction
and
growth
of
fish
and
aquatic
invertebrates
in
the
water
column
via
acute
and/
or
chronic
toxicity.
(
b).
Direct
effects
to
growth
and
development
of
algae
and
vascular
plants
via
acute
toxicity.
(
c).
Direct
effects
to
endangered/
threatened
aquatic
species
via
acute
and/
or
chronic
toxicity.

The
major
endpoints
related
to
terrestrial
environments
at
issue
are:

(
a).
Direct
effects
to
growth
and
development
of
non­
target
plants.
(
b).
Direct
effects
on
survival,
growth
and
reproduction
of
birds,
mammals,
and
by
extension
amphibians
and
reptiles
via
acute
and/
or
chronic
toxicity.

D.
Conceptual
Model
1.
Risk
Hypothesis:

The
Office
of
Pesticide
Programs
uses
a
screening
risk
hypothesis
for
its
initial
risk
assessments.

The
risk
hypothesis
is
that
the
use
of
MCPB
in
accordance
with
the
label
results
in
adverse
effects
on
survival
and/
or
fecundity
of
non­
target
terrestrial
and/
or
aquatic
animals;
and
that
the
use
of
MCPB
according
to
the
label
results
in
adverse
effects
on
survival,
reproduction
and/
or
growth
on
aquatic,
semi­
aquatic
and
terrestrial
plants.
2.
Diagram:
Based
on
an
examination
of
the
physical/
chemical
properties
of
MCPB
and
MCPB
sodium,
the
fate
and
disposition
in
the
environment,
and
mode
of
application
(
e.
g.,
ground
and
aerial
spray
application);
a
conceptual
model
(
Figure
II.
b)
was
developed
that
represents
the
possible
relationships
between
the
stressor,
ecological
endpoints,
and
the
measurement
endpoints.
Risk
to
non­
target
animals
is
also
possible
from
dermal
contact
or
inhalation,
but
because
these
are
not
considered
in
the
risk
assessment,
they
are
not
shown
in
the
diagram
below.
(
Phase
III
3/
07/
06)
    
17
  
147
Figure
II
.
b.
Conceptual
Model
Fig
(
Phase
III
3/
07/
06)
    
19
  
147
E.
Analysis
Plan
This
screening
assessment
uses
a
risk
quotient
(
ratio
of
exposure
concentration
to
effects
concentration)
approach
to
evaluate
the
potential
for
adverse
effects
on
non­
target
terrestrial
and
aquatic
animals.
Calculated
risk
quotients
are
compared
to
predetermined
levels­
of­
concern
(
LOCs)
to
provide
a
preliminary
indication
of
the
potential
for
risk.
Although
risk,
in
the
context
intended
here,
is
often
defined
as
the
likelihood
and
magnitude
of
adverse
ecological
effects,
the
risk
quotient­
based
approach
does
not
provide
a
quantitative
estimate
of
likelihood
and/
or
magnitude
of
an
adverse
effect.
Such
estimates
may
be
possible
through
a
more
refined,
probabilistic
assessment.

Risk
presumptions,
along
with
the
corresponding
RQs,
equations,
and
LOC s
are
summarized
in
Tables
II­
d
to
II­
g.
The
exposure
estimates
in
this
screening
assessment
are
derived
using
maximum
label
rates
and
minimum
application
intervals
for
each
use.

Table
II­
d.
Risk
presumptions
for
terrestrial
animals
(
birds
and
wild
mammals).

Risk
Presumption
RQ
LOC
Acute
EEC1/(
LC50
or
LD50/
ft2
or
LD50/
day)
0.5
Acute
Restricted
Use
EEC1/(
LC50
or
LD50/
ft2
or
LD50/
day)
(
or
LD50
<
50
mg/
kg)
0.2
Acute
Endangered
Species
EEC1/(
LC50
or
LD50/
ft2
or
LD50/
day)
0.1
Chronic
Risk
EEC/
NOEC
1
1
abbreviation
for
Estimated
Environmental
Concentration
(
ppm)
on
avian/
mammalian
food
items
Table
II­
e.
Risk
presumptions
for
aquatic
animals.

Risk
Presumption
RQ
LOC
Acute
EEC1/(
LC50
or
EC50)
0.5
Acute
Restricted
Use
EEC/(
LC50
or
EC50)
0.1
Acute
Endangered
Species
EEC/(
LC50
or
EC50)
0.05
Chronic
Risk
EEC/
NOEC
1
1EEC
=
(
ppm
or
ppb)
in
water
Table
II­
f.
Risk
presumptions
for
terrestrial
and
semi­
aquatic
plants.

Risk
Presumption
RQ
LOC
Acute
Risk
EEC1/
EC25
1
Acute
Endangered
Species
EEC/(
EC05
or
NOEC)
1
(
Phase
III
3/
07/
06)
    
20
  
147
1
EEC
=
lbs
ai/
A
Table
II­
g.
Risk
presumptions
for
aquatic
plants.

Risk
Presumption
RQ
LOC
Acute
High
Risk
EEC1/
EC50
1
Acute
Endangered
Species
EEC/(
EC05
or
NOEC)
1
1
EEC
=
(
ppb/
ppm)
in
water
Three
measures
are
used
to
evaluate
the
risk
hypotheses
developed
in
the
conceptual
model
for
MCPB
usage.
First,
the
measures
of
exposure
are
derived
as
estimated
environmental
concentrations
(
EECs)
based
on
Prism
Exam
model
predictions
and
environmental
fate
data.
Second,
the
measures
of
effect
characterize
the
assessment
endpoints
and
are
based
on
toxicity
data
that
describe
the
effects
of
MCPB
on
individuals
and
species
through
terrestrial
models
such
as;
Trex
(
version
1.1),
Agdrift
(
version
2.01)
and
Terrplant
version
1.0).
Third,
the
measures
of
ecosystem
and
receptor
characteristics
describe
the
attributes
of
the
receptors
and/
or
ecosystems
that
may
be
affected
by
exposure
to
the
stressor
(
i.
e.
behavior
and
life
history
characteristics).
This
analysis
plan
also
identifies
the
data
gaps
and
uncertainties
for
conducting
the
risk
assessment
and
suggests
recommendations
for
new
data
collection.

1.
Preliminary
Identification
of
Data
Gaps
and
Methods:
Environmental
fate
data
are
available
concerning
the
hydrolysis
and
photodegradation
of
MCPB
in
water,
the
biodegradation
of
MCPB
in
soil,
and
the
mobility
of
MCPB
in
soil.
However,
information
is
not
available
concerning
the
fate
of
the
aqueous
phototransformation
products.
There
are
no
acceptable
study
data
on
soil
photolysis
and
aerobic
or
anaerobic
aquatic
biodegradation.

Toxicity
studies
are
available
to
determine
the
potential
acute
effects
to
fish
and
aquatic
invertebrates;
however,
no
toxicity
studies
have
been
conducted
to
determine
potential
chronic
effects
to
fish
and
aquatic
invertebrates.
The
following
chronic
studies
have
not
been
submitted:
early
life­
cycle
fish
study,
full
life­
cycle
fish
study,
and
full
life­
cycle
aquatic
invertebrate
study.
Therefore,
chronic
risk
to
these
taxa
cannot
be
evaluated
and
the
risk
assessment
should
be
considered
incomplete.
Chronic
risk
to
non­
endangered
and
listed
aquatic
animals
cannot
be
dismissed.

Toxicity
studies
are
available
to
determine
the
potential
acute
effects
to
birds,
mammals
and
honey
bees
and
the
potential
reproductive/
developmental
effects
to
mammals.
MCPB
residues
may
affect
the
foraging
behavior
of
herbivores
(
birds,
mammals)
and
of
pollinators.
However,
data
are
not
available
to
determine
the
potential
exposure
levels
from
residues
in
foliage,
flowers
and
seeds.
The
only
residue
study
(
MRID
44754101)
available
examined
residues
on
peas
at
harvest.
Therefore,
the
level
of
residues
that
occurred
directly
after
application
(
which
would
represent
the
highest
concentration
to
which
animals
could
be
exposed)
was
not
specified.
No
toxicity
studies
have
been
conducted
(
Phase
III
3/
07/
06)
    
21
  
147
to
determine
the
effect
of
residues
to
pollinators.
An
MCPA
chronic
bird
study
was
substituted
for
MCPB
which
resulted
in
a
NOAEC
of
1000
mg/
kg­
diet.

Spray
drift
presents
a
potential
risk
to
non­
target
plants
inhabiting
edge
habitats
adjacent
to
target
fields
and
riparian
vegetation
along
streams
and/
or
ponds
in
close
proximity
to
sprayed
fields.
However,
no­
effect
levels
in
the
vegetative
vigor
tests
were
not
established
for
terrestrial
plants.
Also,
the
NOECs
for
aquatic
plants
were
not
determined.
Therefore,
the
magnitude
of
spray
drift
that
would
cause
effects
to
plants
is
not
known.

Potential
risk
to
estuarine/
marine
species
cannot
be
determined
because
studies
were
not
submitted
by
the
registrant.

2.
Measures
to
Evaluate
Risk
Hypotheses
and
Conceptual
Model
Measures
of
Exposure
Based
on
the
conceptual
model
presented
above,
the
potential
exposure
pathways
for
aquatic
species
include
runoff/
leaching,
spray
drift,
and
residues
in
sediments.
The
potential
exposure
pathways
for
terrestrial
species
include
ground
deposition,
runoff/
leaching
and
spray
drift
resulting
in
residues
on
non­
target
plants.
The
exposure
assessment
for
this
risk
assessment
of
MCPB
will
use
Tier
II
models
to
provide
a
more
realistic
characterization
that
reflects
actual
labeled
use.
The
Tier
II
PRZM/
EXAMS
models
will
be
used
to
predict
EECs
in
surface
water.
This
model
provides
peak
concentrations
in
a
variety
of
scenarios
for
ponds
adjacent
to
treated
areas,
and
can
be
used
to
vary
the
level
of
spray
drift
and
surface
runoff
from
a
single
large
rain
event.
No
transformation
products
were
considered
in
the
aquatic
assessment
as
the
environmental
fate
database
was
incomplete
for
degradates.

As
part
of
the
terrestrial
assessment,
EFED
modeled
exposure
concentrations
of
MCPB
to
nontarget
terrestrial
plants
and
animals
following
the
proposed
application
rates
provided
by
the
registrant.
For
terrestrial
birds
and
mammals,
estimates
of
initial
levels
of
MCPB
residues
on
various
food
items,
which
may
be
contacted
or
consumed
by
wildlife,
were
determined
using
the
Kenega­
Fletcher
nomogram
followed
by
a
first
order
decline
model
TREX
1.1.
Exposure
concentrations
for
nontarget
plants
were
estimated
using
the
TerrPlant
1.0
model.
AgDrift
2.0.1
model
provides
further
refinement
of
spray
drift
dispersion
and
deposition
to
terrestrial
plants
located
in
proximity
to
treated
fields.

Measures
of
Effect
Measures
of
effect
are
obtained
from
a
suite
of
registrant­
submitted
guideline
studies
conducted
with
a
limited
number
of
surrogate
species.
The
test
species
are
not
intended
to
be
representative
of
the
most
sensitive
species,
but
rather
were
selected
based
on
their
ability
to
thrive
under
laboratory
conditions.
Consistent
with
EPA
test
guidelines,
the
registrant
has
provided
ecological
effect
data.
Acceptable
guideline
studies
are
available
to
assess
the
acute
toxicity
of
MCPB
sodium
to
aquatic
fish
and
invertebrates,
algae,
(
Phase
III
3/
07/
06)
    
22
  
147
aquatic
vascular
plants,
birds,
mammals,
honey
bees,
and
terrestrial
plants,
including
monocots
and
dicots.
Acceptable
guideline
studies
are
available
to
assess
the
subchronic
and
developmental
effects
to
mammals.

Acute
measures
of
effect
are
the
concentrations
that
produce
50%
mortality
or
growth
reduction
in
the
test
organisms
(
LC
50
s
and
EC
50
s,
respectively).
The
measure
of
effect
for
terrestrial
plants
is
the
EC
25
.
Chronic
effects
endpoints
for
listed
and
non­
listed
plants
are
the
highest
test
concentration
where
there
is
no
observed
adverse
effect
(
NOAECs)
on
survival
and
growth
of
terrestrial
and
aquatic
plants.

III.
ANALYSIS
Analysis
is
a
process
that
examines
the
two
primary
components
of
risk,
exposure
and
effects,
and
their
relationships
between
each
other
and
site
characteristics.
The
objective
is
to
provide
the
ingredients
necessary
for
determining
or
predicting
ecological
responses
to
pesticide
uses
under
exposure
conditions
of
interest.
The
products
of
analysis
provide
the
basis
for
estimating
and
describing
risks
in
risk
characterization.
The
MCPB
analysis
consists
of
evaluating
environmental
fate
data,
modeling
exposure
concentrations
and
evaluating
toxicity
information
to
formulate
potential
risks
to
the
defined
endpoints
shown
in
Figure
II.
b.
The
analysis
is
based
on
Tier
II
modeling
of
estimated
exposure
concentrations
combined
with
toxicity
information
from
MCPB
toxicity
studies.

A.
Use
Characterization
MCPB
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
)
is
formulated
as
a
sodium
salt
in
aqueous
solution.
Methods
of
application
include
controlled
droplet
applicator,
high
volume
ground
sprayer,
low
volume
ground
sprayer,
hand
held
sprayer,
high
volume
spray
(
dilute),
low
volume
spray
(
concentrate),
aerial
and
ground
broadcast,
and
spot
treatment.
Timing
of
application
for
the
one
registered
use
for
peas
is
when
shoots
emerge
until
about
three
leaf
nodes
before
flowering.

Supported
formulations
of
MCPB
are
Thistrol
®
Herbicide
(
71368­
5)
and
Sodium
MCPB
Solution
(
71368­
7).
Copies
of
all
labels
may
be
found
at
http://
www.
cdpr.
ca.
gov/
docs/
epa/
m2.
htm.

The
labels
for
MCPB
do
not
contain
specific
requirements
to
minimize
spray
drift;
only
a
broad
statement
is
included
to
avoid
spray
drift
to
prevent
injury
to
susceptible
crops.
The
exception
is
the
state
of
Florida,
which
has
promulgated
a
rule
(
Organo­
Auxin
Herbicide
Rule)
that
stipulates
that
buffer
zones
up
to
a
half­
mile
wide
be
observed
when
spraying
phenoxy
herbicides.
The
width
of
the
required
buffer
zone
is
dependent
on
the
wind
speed
and
direction,
and
whether
aerial
or
ground
spray
equipment
is
used.
This
has
the
potential
to
reduce
the
exposure
susceptible
non­
target
plants
to
spray
drift.

MCPB
can
be
used
on
green
and
dry
peas.
The
USDA
crop
profiles
suggest
that
as
a
result,
MCPB
may
be
used
throughout
the
country.
For
instance,
USDA
crop
profiles
indicate
dry
and
green
peas
are
grown
in
the
following
states:
Delaware,
Idaho
(
green
peas);
Idaho,
Montana,
Washington
(
dry
peas)
and
Maryland,
Minnesota,
New
York,
Oregon
and
Wisconsin
(
peas).
(
Phase
III
3/
07/
06)
    
23
  
147
The
USGS
also
indicates
MCPB
usage
on
peas
in
Illinios,
Michigan,
Pennsylvania,
New
Jersey
and
Maine.

Because
peas
can
be
grown
throughout
the
country,
a
variety
of
ecosystems
may
be
exposed.
The
crop
profile
for
Maryland
peas
indicates
that
peas
are
grown
in
estuarine
watersheds
which
include
Dorchester
and
Caroline
counties.
Other
crop
profiles
such
as
Delaware
suggest
that
MCPB
may
be
used
in
estuarine
as
well
as
freshwater
environments.
USDA
crop
profiles
and
USGS
1992
use
map
can
be
accessed
through
the
following
websites.
http://
pestdata.
ncsu.
edu/
cropprofiles/
cropprofiles.
cfm
http://
ca.
water.
usgs.
gov/
pnsp/
use92/
mcpb.
html.

B.
Exposure
Characterization
The
MCPB
exposure
characterization
in
this
assessment
combines
the
environmental
fate
data
with
Tier
II
exposure
models
to
estimate
environmental
exposure
concentrations
(
EECs).
Exposure
models
estimate
EECs
following
the
conceptual
diagram
of
MCPB
usage
and
potential
exposure
shown
in
Figure
II.
b.
EECs
for
aquatic
endpoints
are
developed
using
the
Tier
II
surface
water
models
PRZM/
EXAMS.
These
models
are
more
comprehensive
and
determine
EECs
based
on
geographic
areas
nationwide
and
product
use
sites
in
close
proximity
to
water
bodies.
EECs
for
birds
and
terrestrial
mammals
are
estimated
using
the
T­
REX
1.1
model,
and
EECs
for
non­
target
plants
are
estimated
by
the
TerrPlant
1.0
model.

1.
Environmental
Fate
and
Transport
Study
Summaries:
Laboratory
environmental
fate
data
indicate
that
MCPB
is
likely
to
be
mobile,
but
not
persistent
in
the
environment.
Adsorption/
desorption
studies
of
MCPB
and
a
low
octanol­
water
partition
coefficient
indicate
MCPB
to
be
mobile
in
soil
and
soil:
water
systems.
However,
soil
half­
lives
indicate
that
MCPB
would
be
relatively
short­
lived
and
not
likely
to
persist
for
extended
periods
in
soils.
Under
aerobic
soil
conditions,
the
overall
half­
life
was
27
days
and
the
major
transformation
product
was
volatilized
14CO
2.
The
half­
life
for
the
anaerobic
biodegradation
of
[
14C]
MCPB
in
sandy
loam
soil
was
7.8
days
and
the
major
transformation
product
was
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA).

Based
on
the
physical
and
chemical
properties,
MCPB
will
exist
predominately
in
the
ionic
or
salt
form
at
ambient
environmental
pHs.
Based
on
simple
chemical
equilibrium
calculation
for
MCPB
(
a
monobasic
acid
with
a
pKa
of
approximately
4.6),
the
degree
of
ionization
of
MCPB
at
pH
7
is
99.6%,
and
ranges
from
approximately
70%
to
99.99+%
at
pHs
5
and
9,
respectively.
The
only
registered
formulation
for
field
application
is
the
sodium
salt.

The
hydrolysis
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
(
MCPB)
was
studied
in
the
dark
at
25
±
1
°
C
in
sterile
aqueous
0.1
M
buffer
solutions
adjusted
to
pH
5
(
acetate),
pH
7
(
phosphate)
and
pH
9
(
borate)
for
30
days
in
this
acceptable
study.
The
concentration
of
[
14C]
MCPB
decreased
from
94.4%
at
day
0
to
91.5%
of
the
applied
at
study
termination
in
the
pH
5
solution,
from
95.8%
to
91.9%
at
pH
7,
and
from
(
Phase
III
3/
07/
06)
    
24
  
147
95.7%
to
93.2%
of
the
applied
at
pH
9.
No
major
transformation
product
was
detected
in
any
of
the
solutions.
Because
less
than
4%
of
MCPB
hydrolyzed
at
any
pH
tested
during
a
30­
day
period,
MCPB
is
essentially
stable
to
hydrolysis
for
environmental
fate
purposes
(
that
is,
half­
lives
are
indeterminately
long
during
a
30­
day
test
period).
Gross
extrapolation
indicates
half­
lives
to
be
greater
than
500
days
(
MRID
42574301).
The
aqueous
phototransformation
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)

butyric
acid(
MCPB)
was
studied
at
25
±
1
°
C
in
sterile
aqueous
acetate,
phosphate
and
borate
buffer
solutions
at
pH
5,
7
and
9,
respectively.
Irradiation
was
for
30
days
(
12
hours
light/
12
hours
dark)
with
a
filtered
xenon
arc
lamp
light
source.
The
concentrations
of
[
14C]
MCPB
decreased
from
94.4%
at
day
0
to
0.2%
of
the
applied
at
day
30
in
the
pH
5
solution,
from
95.9%
to
<
0.1%
at
pH
7,
and
from
95.7%
to
<
0.1%
at
pH
9.
Five
transformation
products
were
isolated
at
>
10%
of
the
applied:
4
­(
4­
hydroxy­
o­
tolyloxy)
butyric
acid;
2,4­
dihyroxyphenyl
formate;
o­
cresol;
benzoic
acid;
and
2­
hydroxyphenyl
formate.
The
half­
lives
of
MCPB
in
the
irradiated
pH
5,
7
and
9
buffer
solutions
measured
in
this
acceptable
study
were
2.2,
2.6
and
2.4
days,
respectively.
Because
the
wavelengths
and
intensity
of
the
filtered
xenon
arc
lamp
used
in
the
laboratory
experiment
were
equivalent
to
sunlight
and
there
was
no
degradation
in
the
dark
control,
no
adjustments
to
the
half­
lives
are
necessary
(
MRID
42574302).

The
adsorption/
desorption
characteristics
of
phenyl
ring­
labeled
[
14C]
MCPB
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
dissolved
in
methanol
were
studied
in
sterile
sandy
clay
loam
soil
[
pH­
6.09,
organic
carbon
­
1.3%]
from
France,
and
the
following
three
soils
and
one
sediment
from
England:
sand
soil
[
pH
­
7.93,
organic
carbon
­
0.53%],
sandy
loam
soil
[
pH
­
6.08,
organic
carbon
­
0.76%],
clay
loam
soil
[
pH
­
7.6,
organic
carbon
­
2.49%],
and
sandy
loam
aquatic
sediment
[
pH
­
5.95,
organic
carbon
­
2.85%]
in
a
batch
equilibrium
experiment.
The
mean
adsorption
Kads
values
calculated
from
this
acceptable
study
were
1.69,
0.26,
0.65,
0.78,
and
10.58
mL/
g
for
the
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam
soils
and
sandy
loam
sediment,
respectively.
Adsorption
Koc
values
were
129.57,
47.91,
85.54,
31.27,
and
371.17
mL/
g
for
the
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam
soils
and
sandy
loam
sediment,
respectively.
At
the
end
of
the
desorption,
64.0%,
32.18%,
60.22%,
60.59%,
and
24.63%
of
the
adsorbed
amount
was
desorbed
in
the
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam
soils
and
sandy
loam
sediment,
respectively
(
MRID
42693701).

The
aerobic
soil
metabolism
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
(
MCPB)
was
studied
in
sandy
loam
soil
(
pH
in
water
5.38,
organic
carbon
2.3%)
from
the
United
Kingdom
for
120
days
under
aerobic
conditions
in
darkness
at
22
±
1
°
C
and
soil
moisture
of
75%
of
1/
3
bar.
The
major
transformation
product
of
[
14C]
MCPB
was
volatilized
14CO2
which
increased
to
a
maximum
64.9
±
0.6%
of
the
applied
at
65
days
and
was
54.5­
61.8%
at
90­
120
days;
no
organic
volatiles
were
detected.
The
overall
aerobic
half­
life
in
this
acceptable
study
was
27.0
days
(
r2
=
0.774,
0­
120
days)
with
an
initial
half­
life
of
9.1
days
(
r2
=
0.952,
0­
29
days)
and
a
secondary
half­
life
of
79
days
(
r2
=
0.659,
29­
120
days).
Two
minor
transformation
products
identified
in
soil
extracts
were
the
hexose
conjugate
of
(
4­
chloro­
2­
methylphenoxy)­
2­
 ­
glucopyranoside
acetic
acid
minor
(
CHPA)
and
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA),
which
were
detected
at
maximums
of
9.5%
(
8
days)
and
7.2%
(
15
days)
of
the
applied
radioactivity,
respectively,
with
both
decreasing
to
 
2.1%
by
120
days.
Five
additional
unidentified
[
14C]
compounds
were
each
 
5.3%
of
the
applied
at
any
sampling
interval.
(
Phase
III
3/
07/
06)
    
25
  
147
The
registrant
proposed
a
biotransformation
pathway
for
the
degradation
of
MCPB
in
aerobic
soil
indicating
degradation
of
MCPB
to
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA),
which
degrades
to
(
4­
chloro­
2­
methylphenoxy)­
2­
 ­
glucopyranoside
acetic
acid
minor
(
CHPA)
and
conjugates
with
hexose;
and
significant
production
of
CO2.
(
MRID
43247601).

The
anaerobic
soil
metabolism
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
(
MCPB)
was
studied
in
sandy
loam
soil
(
pH
in
water
7.7,
organic
carbon
0.3%)
incubated
for
62
days
under
anaerobic
conditions
(
flooding
plus
nitrogen
atmosphere)
in
darkness
at
25
±
1
°
C
following
4
days
of
aerobic
incubation.
Anaerobic
half­
life
values
of
[
14C]
MCPB
in
the
water,
soil
and
entire
system
using
least
squares
linear
regression
analysis,
based
on
first­
order
kinetics,
of
[
14C]
MCPB
recovered
in
each
sample
were
18.9,
7.8
and
11.4
days,
respectively.
The
major
transformation
product
of
[
14C]
MCPB
was
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA)
detected
at
maximums
of
34.8%
in
the
soil
at
4
days
just
prior
to
flooding,
33.4%
in
the
water
after
14
days
of
anaerobic
incubation,
and
46.9%
in
the
total
soil:
water
system
after
29
days.
After
62
days
of
anaerobic
incubation,
[
14C]
MCPA
was
6.6
±
2.1%
of
the
applied
in
the
soil,
27.8
±
4.8%
in
the
water
and
34.3
±
2.7%
in
the
entire
soil:
water
system
(
MRID
43015501).
This
study
was
classified
as
"
acceptable".

Valid
terrestrial
field
dissipation
and
soil
photolysis
studies
are
not
available.

2.
Measures
of
Aquatic
Exposure
Aquatic
Exposure
Modeling
Aquatic
exposure
concentrations
for
MCPB
in
the
standard
field
pond
were
estimated
using
the
PRZM
3.12
and
EXAMS
2.98
models
in
tandem.
PRZM/
EXAMS
is
a
Tier
II
screening
model
designed
to
estimate
pesticide
concentrations
found
in
water
at
the
edge
of
a
treated
field.
As
such,
it
provides
high­
end
values
of
the
pesticide
concentrations
that
might
be
found
in
ecologically
sensitive
environments
following
pesticide
application.

PRZM/
EXAMS
is
a
multi­
year
runoff
model
that
also
accounts
for
spray
drift
from
single
and
multiple
applications.
In
the
ecological
exposure
assessment,
PRZM/
EXAMS
simulates
a
10
hectare
(
ha)
field
immediately
adjacent
to
a
1
ha
pond,
2
meters
deep
with
no
outlet.
The
geographic
location
of
the
field
is
specific
to
the
crop
being
simulated
using
site
specific
information
on
the
soils,
weather,
cropping,
and
management
factors
associated
with
the
scenario.
The
crop/
location
scenario
is
intended
to
represent
a
highend
vulnerable
site
on
which
the
crop
is
normally
grown.
Based
on
historical
rainfall
patterns,
the
pond
receives
multiple
runoff
events
during
the
years
simulated.

Acute
risk
assessments
are
performed
using
1
in
10
year
peak
EEC
values
for
single
applications
of
MCPB.
Chronic
risk
assessments
for
aquatic
invertebrates
and
fish
are
performed
using
the
average
21­
day
and
60­
day
EECs,
respectively.

Table
III.
a.
presents
the
input
parameters
used
in
the
Tier
II
PRZM/
EXAMS
modeling
for
ecological
assessment
of
MCPB
for
surface
water
sources.
To
simulate
field
application
of
MCPB
to
peas,
two
scenarios
were
selected
representing
different
MCPB
usage
areas
based
on
geography
and
weather.
A
California
lettuce
and
an
Oregon
snap
(
Phase
III
3/
07/
06)
    
26
  
147
bean
scenario
were
chosen
as
representative
of
the
agricultural
practices
and
areas
in
which
peas
are
grown.
The
EECs
for
the
two
scenarios
are
presented
in
Table
III.
b.
The
Oregon
scenario
represents
the
typical
use
of
MCPB
application
to
peas,
and
the
California
scenario
represents
a
reasonable
upper
bound
estimate.
Results
for
the
two
cases
are
similar.
We
also
investigated
several
other
possible
scenarios
(
approximately
six
others),
and
found
all
EECs
to
be
rather
tightly
grouped
in
a
range
from
approximately
15
to
40
µ
g
ae/
L.
The
PRZM/
EXAMS
input
and
output
files
from
the
California
and
Oregon
aquatic
ecological
exposure
assessments
are
presented
in
Appendix
B.

TABLE
III.
a.
PRZM/
EXAMS
Input
Parameters
for
MCPB.

Model
Parameter
Value
Comments
Source
Application
Rate
per
Event
1.68
kg
ae/
acre
(
1.5
lbs
ae/
acre)
application
to
peas
by
ground
and
aerial
spray
application
Label
Number
of
Applications
per
Crop
Season
1
application
per
year;
assumes
one
planting
season
per
year
Label
Spray
Application
Efficiencies
ground
aerial
0.99
0.95
EFED
Guidance,
2002
Spray
Drift
Fraction
ground
aerial
0.01
0.05
EFED
Guidance,
2002
Aerobic
Soil
Metabolism
t
½
78
days
1
estimated
upper
90
th
percentile
MRID
43247601
Anaerobic
Soil
Metabolism
t
½
34
days
2
estimated
upper
90
th
percentile
MRID
43015501
Aerobic
Aquatic
Degradation
t
½
156
days
3
estimated
(
2x
aerobic
soil
metabolism
half­
life)
EFED
Guidance,
2002
Anaerobic
Aquatic
Degradation
t
½
68
days
4
estimated
(
2x
anaerobic
soil
metabolism
half­
life)
EFED
Guidance,
2002
Aqueous
Photolysis
t
½
2.6
days
pH
7
MRID
42574302
Hydrolysis
t
½
stable
MRID
42574301
Kd/
Koc
0.85
mL/
g
5
Average
Kd
MRID
42693701
Molecular
Weight
228.6
Chemical
Formula
Water
Solubility
600
mg/
L
10
x
solubility
Product
Chemistry
Vapor
Pressure
4.0E­
7
torr
Product
Chemistry
Henry's
Law
Constant
(
estimated
at
25
°
C)
3.42
x
10­
9
atmm3
mol
(
Howard
and
Meylan,
1997)
(
Phase
III
3/
07/
06)
    
27
  
147
1
Upper
90th
Percentile
based
on
three
times
the
single
value
for
the
combined/
total
aerobic
soil
metabolism
half
life
of
26
days
for
MCPB,
MCPA,
and
CHPA/
CHPA
hexose
conjugate.
2
Upper
90th
Percentile
based
on
three
times
the
single
anaerobic
soil
metabolism
half
life
of
11.4
days.
3
2x
aerobic
soil
metabolism
half­
life
(
EFED
Modeling
Input
Parameter
Guidance,
2002).
4
2x
anaerobic
soil
metabolism
half­
life
(
EFED
Modeling
Input
Parameter
Guidance,
2002).
5
From
adsorption/
desorption
data
including
Kd
values
of
1.69,
0.26,
0.65,
and
0.78
mL/
g
from
MRID
42693701.

TABLE
III.
b.
Estimated
Environmental
Concentrations
(
µ
g
ae/
L)
of
MCPB
+
Metabolites
(
MCPA
and
CHPA/
CHPA­
hexose)
in
Surface
Water
(
PRZM­
EXAMS)
from
All
Uses
for
Ecological
Assessment.

Simulation
Scenario
Concentration
(
µ
g
ae/
L)

Crop
and
Location
Application
rate
1
in
10
year
Peak
21
Day
Max.
60
Day
Max.

Lettuce
(
CA)
(
Surrogate
for
Peas)
1
.5
lbs
ae/
acre
(
1.68
kg
ae/
ha)
ground
spray
aerial
spray
40.4
43.2
39.0
41.7
36.4
38.9
Snap
Beans
(
OR)
(
Surrogate
for
Peas)
1
.5
lbs
ae/
acre
(
1.68
kg
ae/
ha)
ground
spray
aerial
spray
29.5
33.1
29.0
32.5
28.1
31.5
The
following
surrogate
scenarios
are
among
those
available
in
PRZM/
EXAMS
to
simulate
peas
grown
in
different
regions
of
the
US:
California
lettuce
scenario
represents
a
reasonable
upper
bound
estimate
for
areas
in
which
peas
are
or
may
be
grown.
Oregon
snap
bean
scenario
represents
a
typical
use
scenario
for
areas
in
which
peas
are
grown.
Input
and
output
for
PRZM3.12/
EXAMS2.98
modeling
is
in
Appendix
B.

Aquatic
Exposure
Monitoring
and
Field
Data
Surface
water
and
groundwater
monitoring
data
were
not
available
for
evaluation
in
this
risk
assessment.

3.
Measures
of
Terrestrial
Exposure
Terrestrial
Exposure
Modeling
For
birds
and
mammals,
MCPB
concentrations
on
food
items,
based
on
data
from
Hoerger
and
Kenaga
(
1972)
and
Fletcher
et
al.
(
1994),
are
predicted
using
a
first­
order
residue
decline
method.
EFEDs
T­
REX
(
Ver.
1.1)
model
predicts
maximum
and
mean
EECs
resulting
from
the
single
application
of
MCPB.
Acute
and
Chronic
RQs
are
calculated
using
these
EECs
and
appropriate
toxicity
data.

TABLE
III.
c.
Estimated
Environmental
Concentrations
(
ppm
ae)
of
MCPB
Acid
on
Terrestrial
Food
Items
from
Use
on
Peas.

Simulation
Scenario
Concentration
(
ppm
ae)

Crop
Food
item
Maximum
Mean
Peas
Short
Grass
Tall
Grass
Broadleaf
Plants/
Small
Insects
360
165
202.5
127.5
54
67.5
(
Phase
III
3/
07/
06)
    
28
  
147
TABLE
III.
c.
Estimated
Environmental
Concentrations
(
ppm
ae)
of
MCPB
Acid
on
Terrestrial
Food
Items
from
Use
on
Peas.

Simulation
Scenario
Concentration
(
ppm
ae)

Crop
Food
item
Maximum
Mean
Fruits/
Pods/
Seeds/
Large
Insects
22.5
10.5
Effects
on
non­
target
terrestrial
plants
are
most
likely
to
occur
as
a
result
of
spray
drift
from
aerial
and
ground
applications
of
the
liquid
formulation.
Spray
drift
is
an
important
factor
in
characterizing
the
risk
of
MCPB
to
non­
target
plants.
The
TerrPlant
(
Ver.
1.0)
model
predicts
EECs
for
terrestrial
plants
located
adjacent
to
the
treated
field.
MCPB
applied
according
to
label
directions
as
a
liquid
spray
for
ground
or
aerial
applications
may
impact
non­
target
plants
for
some
distance
from
the
application
site
depending
on
droplet
size,
wind
speed,
and
other
factors.
The
MCPB
product
label
does
not
specify
a
required
or
recommended
droplet
size
for
spray
applications.
MCPB
applied
as
a
fine
or
medium
spray
has
the
potential
to
damage
off­
target
plants.
In
addition
to
the
TerrPlant
modeling
of
EECs,
refinement
of
spray
drift
from
treated
fields
was
assessed
with
the
AgDrift
(
Ver.
2.0.1)
model.
The
AgDrift
model
provides
estimates
of
drift
dispersion
and
deposition
as
the
result
of
ground
and
aerial
spray
droplet
and
nozzle
size,
wind
speed
and
distance
from
the
treated
field.

Residue
Studies
No
residues
of
MCPB
or
its
primary
degradate,
MCPA,
were
detected
on
peas
and
pods
at
harvest
after
broadcast
treatment
of
Thistrol
(
1.5
lbs.
ae/
acre)
in
eight
field
trials
conducted
in
1999
(
MRID
44754101).
Succulent
peas
and
pods
were
sampled
29­
34
days
after
treatment
with
MCPB
(
1.5
lbs.
ae/
acre)
and
dried
peas
were
sampled
42­
64
days
after
MCPB
treatment
and
analyzed
for
residues.
The
maximum
residue
to
which
animals
could
be
exposed
would
occur
directly
after
application.
The
decline
of
residues
from
this
maximum
level
was
therefore
not
measured.
To
assess
the
potential
risk
to
birds
and
terrestrial
animals
from
exposure
to
residues
immediately
following
application
to
pea
plants,
EFED
modeled
exposure
concentrations
using
TRex
(
ver.
1.1).
These
modeled
residue
concentrations
on
pea
plants
provide
the
avian
and
terrestrial
mammal
EECs
for
risk
calculations.
Since
the
foliar
dissipation
half­
life
could
not
be
determined
from
the
residue
study,
a
default
value
of
35
days
was
used.

C.
Ecological
Effects
Characterization
1.
Aquatic
Effects
Characterization
The
following
tables
present
measures
of
effect
both
in
terms
of
active
ingredient
and
acid
equivalents.
Conversion
from
active
ingredient
to
acid
equivalents
was
made
in
accordance
with
molecular
weight
differences.
One
gram­
mole
of
MCPB
acid
has
a
mass
of
228.67
grams
and
one
gram­
mole
of
MCPB
sodium
salt
has
a
mass
of
250.66
grams;
therefore,
one
unit
of
the
salt
would
be
equivalent
to
0.912
units
of
the
acid.
Hence,
the
LC50
values
from
the
toxicity
tests
with
MCPB
sodium
were
converted
to
acid
equivalents
by
multiplying
the
values
by
0.91.
(
Phase
III
3/
07/
06)
    
29
  
147
TABLE
III.
d.
Summary
of
endpoints
for
MCPB
acute
and
chronic
aquatic
toxicity
studies
for
RQ
evaluation
Endpoint
Environment/
Species
Toxicity
Value
Used
in
Risk
Assessment
MRID#
Comment
Freshwater
Rainbow
Trout
(
TGAI)
96­
hr
LC50
=
3.9
mg
ae/
L
4253260
8
Acceptable
Acute
Toxicity
to
Fish
Estuarine/
mari
ne
No
data
(
TGAI)
No
data
NA
No
studies
were
submitted
Freshwater
No
data
(
TGAI)
No
data
NA
No
studies
were
submitted
Chronic
Toxicity
to
Fish
Estuarine/
mari
ne
No
data
No
data
NA
No
studies
were
submitted
Freshwater
Daphnia
magna
(
TGAI)
48­
hr
EC50
=
50.0
mg
ae/
L
4253260
2
Acceptable
Acute
Toxicity
to
Invertebrates
Estuarine/
mari
ne
No
data
(
TGAI)
No
data
NA
No
studies
were
submitted
Freshwater
No
data
(
TGAI)
No
data
NA
No
studies
were
submitted
Chronic
Toxicity
to
Invertebrates
Estuarine/
mari
No
data
NA
No
studies
were
submitted
(
Phase
III
3/
07/
06)
    
30
  
147
Endpoint
Environment/
Species
Toxicity
Value
Used
in
Risk
Assessment
MRID#
Comment
ne
No
data
Toxicity
to
Aquatic
Plants
Vascular
Duckweed
(
TGAI)
NonVascular
Green
Algae
(
TGAI)
EC50
=
0.21
mg
ae/
L
NOEC
=
<.
01mg
ae/
L*
EC50
=
0.38
mg
ae/
L
NOEC
=
<.
31mg
ae/
L*
4.25e+
15
Based
on
frond
production
Based
on
reduced
cell
density
*
NOEC
can
not
be
determined
due
to
non­
discreet
toxicity
value
therefore
definitive
endangered
species
RQs
can
not
be
calculated.
EC05
was
not
available.

Freshwater
Fish,
Acute
Fish
toxicity
studies
for
two
freshwater
species
using
the
TGAI
are
required
to
establish
the
acute
toxicity
of
MCPB
to
fish.
The
preferred
test
species
are
rainbow
trout
(
a
coldwater
fish)
and
bluegill
sunfish
(
a
warmwater
fish).
The
acute
studies
that
were
submitted
that
tested
the
parent
compound
showed
that
MCPB
sodium
is
moderately
toxic
to
the
more
sensitive
coldwater
rainbow
trout
(
LC
50
3.9
mg
ae/
L)
and
slightly
toxic
to
the
warmwater
bluegill
(
LC
50
12.7
mg
ae/
L).
EFED
will
use
(
LC
50
3.9
mg
ae/
L)
for
evaluating
acute
risk
to
freshwater
fish.
The
guideline
(
72­
1)
is
fulfilled
(
MRID
42532608;
MRID
42532601).

TABLE
III.
e.
Freshwater
Fish
Acute
Toxicity
for
MCPB
Sodium.

Species
96­
hour
LC50
(
mg
ai/
L)
(
nominal)
96­
hour
LC50
(
mg
ae/
L)
(
nominal)
Toxicity
Category
MRID
No.
Author/
Year
Study
Classification
Bluegill
sunfish
(
Lepomis
macrochirus)
14
12.7
Slightly
toxic
42532601
Bettencourt,
1992
Acceptable
Rainbow
trout
(
Oncorhynchus
mykiss)
4.3
3.9
Moderately
toxic
42532608
Bettencourt,
1992
Acceptable
Studies
performed
by
the
registrant
for
the
anaerobic
soil
degradate
MCPA
indicate
that
it
is
less
toxic
to
fish
(
LC
50
values
ranging
from
>
68
­
>
79
mg
ae/
L).

Freshwater
Invertebrates,
Acute
(
Phase
III
3/
07/
06)
    
31
  
147
A
freshwater
aquatic
invertebrate
toxicity
test
using
the
TGAI
is
required
to
establish
the
toxicity
of
MCPB
to
aquatic
invertebrates.
The
preferred
test
species
is
Daphnia
magna.
The
data
that
were
submitted
that
tested
the
parent
compound
showed
that
MCPB
sodium
is
slightly
toxic
to
Daphnia
magna
with
an
acute
48­
hour
EC
50
value
of
50
mg
ae/
L.
EFED
will
use
this
value
for
evaluating
acute
risk
to
freshwater
invertebrates.
The
guideline
requirement
(
72­
2)
for
acute
invertebrate
toxicity
is
fulfilled
(
MRID
42532602).

TABLE
III.
f.
Freshwater
Invertebrate
Acute
Toxicity
for
MCPB
Sodium.

Species
48­
hour
EC50
(
mg
ai/
L)
48­
hour
EC50
(
mg
ae/
L)
Toxicity
category
MRID
No.
Author/
Year
Study
Classificatio
n
Waterflea
(
Daphnia
magna)
55
50
Slightly
toxic
42532602
Putt,
1992
Acceptable
A
study
performed
by
the
registrant
for
MCPA
indicates
that
the
degradate
is
practically
non­
toxic
to
aquatic
invertebrates
with
an
EC
50
of
>
184
mg
ae/
L.

Freshwater
Fish,
Chronic
A
freshwater
fish
early
life­
stage
test
and
life
cycle
fish
test
using
the
TGAI
were
not
submitted
by
the
registrant.
Therefore,
the
guidelines
(
72­
4a;
72­
5)
were
not
fulfilled.

Freshwater
Invertebrate,
Chronic
A
freshwater
aquatic
invertebrate
life­
cycle
test
using
the
TGAI
was
not
submitted
by
the
registrant.
The
preferred
test
is
a
21­
day
life
cycle
study
with
Daphnia
magna.
The
guideline
(
72­
4b)
was
not
fulfilled.

Freshwater
Field
Studies
Aquatic
field
studies
were
not
submitted.

Estuarine/
Marine
Fish
and
Invertebrate,
Acute
and
Chronic
Estuarine/
marine
studies
were
not
submitted
by
the
registrant.
Therefore,
the
following
guidelines
were
not
fulfilled:
(
72­
3a
for
acute
fish
­
sheepshead
minnow;
72­
3b
for
acute
invertebrate
­
eastern
oyster;
72­
4d
for
mysid
life
cycle).

Aquatic
Plants
Several
aquatic
plant
toxicity
studies
using
the
TGAI
were
submitted
to
establish
the
toxicity
of
MCPB
to
non­
target
aquatic
plants.
The
recommendation
is
for
testing
of
five
species:
freshwater
green
alga
(
Selenastrum
capricornutum),
duckweed
(
Lemna
gibba),
marine
diatom
(
Skeletonema
costatum),
blue­
green
algae
(
Anabaena
flos­
aquae),
and
a
freshwater
diatom.
The
EC
50
for
the
freshwater
vascular
plant
(
duckweed)
is
0.21
mg
(
Phase
III
3/
07/
06)
    
32
  
147
ae/
L,
based
on
reduced
frond
production;
and
the
lowest
EC
50
for
freshwater
nonvascular
plants
is
0.38
mg
ae/
L,
based
on
reduced
cell
density
in
the
green
algae
study.
Studies
submitted
for
the
algal
species
indicate
that
the
green
algae
is
more
sensitive
to
MCPB
sodium
than
the
blue­
green
algae
causing
reductions
in
cell
density
at
the
lowest
level
tested
(
0.31
mg
ae/
L).
The
freshwater
diatom
was
more
sensitive
to
MCPB
sodium
than
the
marine
diatom
causing
reductions
in
cell
density
at
test
levels
as
low
as
0.12
mg
ae/
L.
The
aquatic
vascular
plant,
duckweed
was
the
most
sensitive
of
the
five
aquatic
species
tested.
Concentrations
as
low
as
0.15
mg
ae/
L
resulted
in
chlorosis,
curling,
and
decreased
root
formation
in
the
plant.
In
addition,
frond
biomass
was
significantly
reduced
at
0.42
mg
ae/
L.
The
guideline
requirements
(
122­
2
and
123­
2)
are
fulfilled;
MRID
42532603;
MRID
42532604;
MRID
42532605;
MRID
42532606;
and
MRID
42532609)
for
the
five
required
species.

TABLE
III.
g.
Non­
target
Aquatic
Plant
Toxicity
for
MCPB
Sodium.(
ai)/
MCPB
acid
(
ae)

Species
[
Study
Type]
EC50/
NOEC
(
mg
ai/
L)
EC50/
NOEC
(
mg
ae/
L)
Endpoints
Affected
MRID
No.
Author,
Year
Study
Classification
Duckweed
(
Lemna
gibba)
[
Tier
I]
0.23/<
0.011
1.7/
0.17
0.21/<
0.01*

1.55/
0.15
Frond
production
Frond
biomass
42532604
Hoberg,
1992
Acceptable
Green
Algae
(
Selenastrum
capricornutum)
[
Tier
I]
0.42/<
0.34
0.38/<
0.31*
Cell
density
42532605
Hoberg,
1992
Acceptable
Blue­
green
Algae
(
Anabaena
flosaquae
[
Tier
I]
>
2.1/
2.1
>
1.9/
1.9
Cell
density
42532603
Hoberg,
1992
Acceptable
Diatom
(
Navicula
pelliculosa)
[
Tier
I
&
II]
0.71/
0.048
0.65/
0.044
Cell
density
42532609
Hoberg,
1992
Acceptable
Diatom
(
Skeletonema
costatum)
[
Tier
I
&
II]
1.5/<
0.11
1.36/
0.10
Cell
density
42532606
Hoberg,
1992
Acceptable
*
Can
not
determine
a
NOEC
due
to
a
non­
discreet
toxicity
value.
Endangered
species
risk
quotient
can
not
be
calculated
without
a
NOEC.

Aquatic
plant
studies
with
the
anaerobic
soil
degradate
MCPA
acid
indicate
that
the
toxicity
is
very
similar
to
MCPB
with
the
EC
50
for
the
freshwater
vascular
plant
(
duckweed)
of
0.17
mg
ae/
L
(
MRID
43126501)
and
the
lowest
EC
50
for
the
freshwater
non­
vascular
plant
(
diatom)
of
0.63
mg
ae/
L
(
MRID
43083202).

2.
Terrestrial
Effects
Characterization
The
following
tables
present
measures
of
effect
both
in
terms
of
active
ingredient
and
acid
equivalents.
Conversion
from
active
ingredient
to
acid
equivalents
was
made
in
accordance
with
molecular
weight
differences.
One
gram­
mole
of
MCPB
acid
has
a
mass
of
228.67
grams
and
one
gram­
mole
of
MCPB
sodium
salt
has
a
mass
of
250.66
grams;
therefore,
one
unit
of
the
salt
would
be
equivalent
to
0.912
units
of
the
acid.
(
Phase
III
3/
07/
06)
    
33
  
147
Hence,
the
LC50
values
from
the
toxicity
tests
with
MCPB
sodium
were
converted
to
acid
equivalents
by
multiplying
the
values
by
0.91.

Birds,
Acute
An
oral
toxicity
study
using
the
technical
grade
of
the
active
ingredient
(
TGAI)
is
required
to
establish
the
acute
toxicity
of
MCPB
to
birds.
The
preferred
guideline
test
species
is
either
mallard
duck
(
a
waterfowl)
or
bobwhite
quail
(
an
upland
gamebird).
The
data
that
were
submitted
report
that
the
14­
day
oral
LD
50
is
257
mg
ae/
kg.
The
NOEL
was
not
determined
due
to
abnormal
effects
at
the
lowest
level
tested.
Observed
effects
including
lethargy,
dyspnea,
loss
of
righting
reflex
and
diarrhea.
Gross
necropsy
showed
white
areas/
film
on
the
heart,
liver,
gizzard,
gallbladder,
crop
or
intestines.
Based
on
these
results,
MCPB
is
categorized
as
moderately
toxic
to
avian
species
on
an
acute
oral
basis;
the
guideline
(
71­
1)
is
fulfilled
(
MRID
42560801).

TABLE
III.
h.
Avian
Acute
Oral
Gavage
Toxicity
for
MCPB
Sodium.
(
ai)/
MCPB
Acid
(
ae)

Species
LD50
(
mg
LD50
(
mg
Toxicity
Category
MRID
No.
Author,
Year
Study
Classification
Northern
bobwhite
quail
(
Colinus
virginianus)
282
257
Moderately
toxic
42560801
Pederson
and
Helsten,
1992
Acceptable
Two
dietary
studies
using
the
TGAI
are
required
to
establish
the
acute
toxicity
of
MCPB
to
birds.
The
preferred
test
species
are
mallard
duck
and
bobwhite
quail.
The
data
that
were
submitted
show
that
the
8­
day
acute
dietary
LC
50
for
both
species
was
>
4,550
ppm
ae;
therefore,
MCPB
sodium
is
categorized
as
practically
non­
toxic
to
avian
species
on
an
acute
dietary
basis.
The
8­
day
NOELs
for
each
species
based
on
sublethal
effects
(
reduced
body
weight
gain)
were
1138
ppm
ae.
In
addition,
gross
necropsy
revealed
white
spots
on
the
liver
of
one
bird
and
a
dark
red
spot
on
the
liver
of
another
bird.
The
guideline
(
71­
2)
is
fulfilled
(
MRID
42560802;
MRID
42560803).

TABLE
III.
i.
Avian
Acute
Dietary
Studies
for
MCPB
Sodium
(
ai)/
MCPB
Acid
(
ae)

Species
8­
Day
LC50
(
ppm
ai)
8­
Day
LC50
(
ppm
ae)
Toxicity
Category
MRID
No.
Author,
Year
Study
Classification
Northern
bobwhite
quail
(
Colinus
virginianus)
>
5,000
>
4,550
Practically
non­
toxic
42560802
Pederson
and
Helsten,
1992
Acceptable
Mallard
duck
(
Anas
platyrhynchos)
>
5,000
>
4,550
Practically
non­
toxic
42560803
Pederson
and
Helsten,
1992
Acceptable
Avian
toxicity
studies
performed
to
determine
the
toxicity
of
the
anaerobic
soil
degradate
MCPA
indicate
similar
results
to
MCPB
sodium
(
oral
LD
50
221
to
377
mg
ae/
kg­
bw
in
bobwhite
quail;
acute
dietary
LC
50
>
4,680
mg
ae/
kg­
diet
for
both
bobwhite
quail
and
mallard
duck).
(
Phase
III
3/
07/
06)
    
34
  
147
Birds,
Chronic
Avian
reproduction
studies
using
the
TGAI
are
usually
required
for
pesticide
registration
because
birds
may
be
subject
to
repeated
or
continuous
exposure
to
the
pesticide,
especially
preceding
or
during
the
breeding
season.
The
preferred
test
species
are
mallard
duck
and
bobwhite
quail.
No
chronic
bird
studies
were
submitted
for
MCPB.
EFED
considered
MCPA
as
a
substitute
for
MCPB
for
chronic
risk
to
birds,
because
the
LD50
for
bobwhite
quail
suggests
that
the
acute
potency
of
MCPB
lies
within
the
range
of
toxicity
for
acid
equivalent
MCPA.
Also,
rapid
dissociation
of
MCPB
to
MCPA
is
expected
to
occur
in
the
bird
gut
due
to
the
chemical
properties
of
MCPB.
The
chronic
bird
study
for
MCPA
with
bobwhite
quail
has
a
NOAEC
of
1000
mg/
kg­
diet
(
MRID
#
435052­
01)
.
No
further
studies
are
required
for
chronic
risk
to
birds
for
MCPB
at
this
time.

Mammals,
Acute
Wild
mammal
testing
is
required
on
a
case­
by­
case
basis,
depending
on
the
results
of
lower
tier
laboratory
mammalian
studies,
intended
use
pattern
and
pertinent
environmental
fate
characteristics.
In
most
cases,
rat
or
mouse
toxicity
values
obtained
from
the
Agency's
Health
Effects
Division
(
HED)
substitute
for
wild
mammal
testing.
These
toxicity
values
are
reported
below.

The
results
indicate
that
MCPB
is
categorized
as
slightly
toxic
to
practically
non­
toxic
to
small
mammals
on
an
acute
oral
basis
(
LD
50
values
range
from
912
­
7,400
mg
ai/
kg/
day).
The
guideline
81­
1
is
fulfilled
(
MRID
116340;
MRID
144801).

TABLE
III.
j.
Mammalian
Acute
Toxicity
for
MCPB.

Species
%
Purity
Test
Type
Toxicity
Affected
Endpoints
MRID
No.
Study
author
Classification
Rat
(
Rattus
norvegicus)
Tech
Acute
oral
LD50
=
3100­
5800mg
ai/
kg/
day
(
males)
LD50
=
3800­
74
00mg
ai/
kg/
day
(
females)
Mortality
144801
Kynoch,
1985
Acceptable
Rat
(
Rattus
norvegicus)
Tech
Acute
oral
LD50
=
912­
2700
mg
ai/
kg/
day
(
males)
LD50
=
969­
2981
mg
ai/
kg/
day
(
females)
Mortality
116340
Holsing,
1969
Acceptable
Mammals,
Subchronic
and
Developmental/
Reproductive
Three
subchronic
feeding
studies
were
performed
with
MCPB.
In
the
two
dog
studies,
reproductive
effects,
including
testicular
and
prostate
atrophy
and
curtailment
of
spermatogenic
activity,
were
observed.
In
the
acceptable
dog
study
(
MRID
42883603),
the
LOAEL
was
44
mg
ai/
kg/
day
based
on
reduced
testes
weights
and
physiological
changes
in
clinical
chemistry.
The
NOAEL
was
25
mg
ai/
kg/
day.
Clinical
chemistry
changes
in
these
studies
(
increase
in
creatinine
and
urea
nitrogen)
were
also
related
to
MCPB
exposure.
In
the
rat
study,
the
decreased
food
consumption
and
body
weight
gains
were
attributed
to
the
lack
of
palatability
of
MCPB
in
the
feed.
Because
no
microscopic
effects
were
observed
in
the
rat
study,
the
other
effects
were
considered
not
to
be
toxicologically
significant.
The
guidelines
82­
1a
and
82­
1b
are
fulfilled
(
MRID
42883602;
MRID
42883603).
(
Phase
III
3/
07/
06)
    
35
  
147
In
developmental
toxicity
studies
with
rats
and
rabbits,
maternal
toxicity
was
observed
at
doses
ranging
from
20
­
100
mg/
kg/
day.
In
the
rat
study,
the
maternal
toxicity
observed
at
100
mg
ai/
kg/
day
included
decreased
body
weights
and
body
weight
gains
during
gestation.
In
the
rabbit
study,
maternal
toxicity
observed
at
20
mg
ai/
kg/
day
included
maternal
deaths,
clinical
signs
of
toxicity,
decrease
in
body
weight
gain
during
treatment,
and
change
in
color
of
liver
and
kidneys.

Developmental
effects
were
observed
in
rats
at
a
dose
of
100
mg
ai/
kg/
day,
including
decreased
mean
body
weights/
litter
for
males
and
females,
increases
in
unossified
or
poorly
ossified
sites
and
increases
in
several
other
skeletal
variations.
No
malformations
or
variations
were
observed
in
the
rabbit
fetuses
at
the
highest
dose
tested,
20
mg
ai/
kg/
day.
EFED
will
use
the
NOAEL
for
maternal
toxicity
of
5
mg
ai/
kg/
day
from
the
rabbit
study
for
evaluating
the
developmental
toxicity
of
MCPB
acid
to
mammals.
The
guideline
83­
3
is
fulfilled
(
MRID
40865401;
MRID
40865402).

Maternal
toxicity
and
developmental
effects
were
also
observed
in
a
2­
generation
reproduction
study
with
rats
exposed
to
the
degradate
MCPA
(
MRID
40041701).
The
NOAEL
for
maternal
toxicity
was
7.5
mg
ai/
kg/
day
and
the
LOAEL
was
22.5
mg
ai/
kg/
day
based
on
increased
absolute
and
relative
ovary
weights.
No
maternal
mortality
was
observed
with
exposure
to
MCPA.
The
LOAEL
for
offspring
toxicity
was
22.5
mg
ai/
kg/
day
based
on
decreased
pup
weight
gain
during
lactation;
the
NOAEL
was
7.5
mg
ai/
kg/
day.
No
LOAEL
was
established
for
developmental
toxicity.

TABLE
III.
k.
Mammalian
Chronic
and
Developmental/
Reproductive
Toxicity
for
MCPB.

Species
%
Purity
Test
Type
Toxicity
ai
Affected
Endpoints
MRID
No.
Study
author
Classification
Dog
NA
Subchronic
feeding
­
13
weeks
NOEL
=
480
ppm
LOEL
=
1600
ppm
Reproduction1
116345
Rhodia,
1970
Supplemental
Dog
91.1
Subchronic
feeding
­
13
weeks
NOEL
=
25
mg
ai/
kg/
day
LOEL
=
44
mg
ai/
kg/
day
Reproduction2
42883603
Dalgard,
1993
Acceptableminimum
Rat
91.1
Subchronic
feeding
­
13
weeks
NOEL
=
158
mg
ai/
kg/
day
No
effects
42883602;
42883601
Trutter,
1993
Acceptableminimum
Rat
97.6
Development
al
NOAEL/
LOAEL
=
25/
100
mg
ai/
kg/
day
NOAEL/
LOAEL=
25/
100
mg
ai/
kg/
day
Maternal
tox3
Developmental
40865402
Tyl,
1988
Acceptable
Rabbit
97.6
Development
al
NOAEL/
LOAEL
=
5/
20
mg
ai/
kg/
day
NOAEL
=
20
mg
ai/
kg/
day
Maternal
tox4
Developmental
40865401
Tyl
&
Neeper­
Bradley,
1988
Acceptable
Rat
(
MCPA)
94.8%
Reproduction
NOAEL/
LOAEL
=
7.5/
22.5
mg
ai/
kg/
day
NOAEL/
LOAEL
=
7.5/
22.5
mg
ai/
kg/
day
NOAEL
=
22.5
mg
ai/
kg/
day
Maternal
tox5
Offspring
tox
Developmental
40041701
MacKenzie,
1986
Acceptable
(
Phase
III
3/
07/
06)
    
36
  
147
1
Testicular
and
prostate
atrophy;
curtailment
of
spermatogenic
activity.

2
Reduced
testes
weights;
physiological
changes
in
clinical
chemistry.

3
Maternal
toxicity
­
Decreased
body
weight
and
body
weight
gain
during
gestation.
Developmental
toxicity
­
Decreased
mean
body
weights/
litter;
increases
in
unossified
or
poorly
ossified
sites;
skeletal
variations.

4
Maternal
toxicity
­
Death,
clinical
signs
of
toxicity,
decrease
in
body
weight
gain,
change
in
color
of
liver
and
kidneys.
Developmental
toxicity
­
No
malformations
or
variations
were
observed
in
the
fetuses.
5Maternal
toxicity
­
Increased
absolute
and
relative
ovary
weights
Offspring
toxicity
­
Decreased
pup
weight
gain
during
lactation.
Developmental
toxicity
­
No
malformations
were
observed
in
the
fetuses.

Insects,
Acute
Contact
A
honey
bee
acute
contact
study
using
the
TGAI
is
required
for
MCPB
because
its
foliar
application
treatment
use
will
result
in
honey
bee
exposure.
The
acute
contact
LD
50
,
using
the
honey
bee,
Apis
mellifera,
is
an
acute
contact,
single­
dose
laboratory
study
designed
to
estimate
the
quantity
of
toxicant
required
to
cause
50%
mortality
in
a
test
population
of
bees.
The
acute
contact
LD
50
for
MCPB
sodium
is
>
23
µ
g
ae/
bee
and
it
is,
therefore,
classified
as
practically
non­
toxic
to
bees
on
a
contact
exposure
basis.
The
guideline
(
141­
1)
is
fulfilled
(
MRID
42532607).
No
acute
contact
studies
were
available
for
the
degradate
MCPA.

TABLE
III.
l.
Non­
target
Insects
­
Acute
Contact
for
MCPB
Sodium
(
ai)/
MCPB
Acid
(
ae)

Species
LD50
(
µ
g
ai/
bee)
LD50
(
µ
g
ae/
bee)
Toxicity
Category
MRID
No.
Author/
Year
Study
Classification
Honey
Bee
(
Apis
mellifera)
>
25
>
23
Relatively
non­
toxic
42532607
Maggi,
1992
Acceptable
Insects,
Residual
Contact
A
honey
bee
toxicity
of
residues
on
foliage
study
is
required
on
an
end­
use
product
for
any
pesticide
intended
for
outdoor
application
when
the
proposed
use
pattern
indicates
that
honey
bees
may
be
exposed
to
the
pesticide
and
when
the
formulation
contains
one
or
more
active
ingredients
having
an
acute
contact
honey
bee
LD
50
which
falls
in
the
moderately
toxic
or
highly
toxic
range.
The
purpose
of
this
guideline
study
is
to
develop
data
on
the
residual
toxicity
to
honey
bees.
Bee
mortality
determinations
are
made
from
bees
exposed
to
treated
foliage
harvested
at
various
time
periods
after
treatment.
No
residue
toxicity
study
was
submitted
by
the
registrant;
however,
the
acute
contact
honey
bee
LD
50
falls
in
the
relatively
non­
toxic
range.

Terrestrial
Plants
Terrestrial
Tier
II
studies
are
required
for
any
pesticide
showing
a
negative
response
equal
to
or
greater
than
25%
in
Tier
I
studies.
Tier
I
and
II
terrestrial
plant
toxicity
studies
were
conducted
to
establish
the
toxicity
of
MCPB
to
non­
target
terrestrial
plants.
The
recommendations
for
seedling
emergence
and
vegetative
vigor
studies
are
for
testing
of
(
1)
six
species
of
at
least
four
dicotyledonous
families,
one
species
of
which
is
soybean
(
Glycine
max)
and
the
second
of
which
is
a
root
crop,
and
(
2)
four
species
of
at
least
two
monocotyledonous
families,
one
of
which
is
corn
(
Zea
mays).
The
guidelines
(
122­
1a;
122­
1b;
123­
1a;
123­
1b)
are
fulfilled
(
MRID
42560804).
The
guideline
study
met
(
Phase
III
3/
07/
06)
    
37
  
147
the
requirements
for
Tier
II
seedling
emergence
testing
for
all
ten
required
species;
for
Tier
II
vegetative
vigor
testing
for
cabbage,
cucumber,
lettuce,
onion,
ryegrass,
radish,
soybean,
and
tomato;
and
for
Tier
I
vegetative
vigor
testing
for
corn
and
oat.
Tier
II
vegetative
vigor
testing
was
not
required
for
corn
and
oat
because
results
from
Tier
I
testing
showed
that
<
25%
detrimental
effects
were
observed
from
the
maximum
label
rate.

These
studies
indicate
that
the
most
sensitive
monocot
species
in
seedling
emergence
tests
was
the
onion
with
the
lowest
EC
25
of
0.02
lb
ae/
A
based
on
shoot
length.
This
value
represents
0.093%
of
the
maximum
application
rate
for
MCPB
sodium.
The
most
sensitive
dicot
species
tested
was
cabbage
with
an
EC
25
of
0.016
lb
ae/
A
in
the
seedling
emergence
study
based
on
shoot
length.
The
most
sensitive
monocot
in
the
vegetative
vigor
test
was
also
onion,
with
an
EC25
of
0.016
lb
ae/
A
based
on
shoot
weight.
The
most
sensitive
dicot
species
tested
was
tomato
with
an
extrapolated
EC
25
of
0.0017
lb
ae/
A
in
the
seedling
emergence
study
based
on
shoot
weight.

The
observed
non­
lethal
effects
included
brown
leaf
tips
in
cabbage,
corn,
onion,
ryegrass,
radish,
and
soybean;
necrosis
in
corn,
radish,
onion,
and
soybean;
chlorosis
in
onion,
cucumber,
and
lettuce;
stem
tumors
in
soybean
and
tomato;
leaf
curl
in
tomato,
and
decreased
size
in
cabbage,
cucumber,
lettuce,
onion,
and
ryegrass.

There
is
significant
uncertainty
in
the
vegetative
vigor
EC
25
values
for
dicots,
because
they
were
extrapolated
below
the
lowest
dose
tested
in
the
study.
Furthermore,
the
NOEC
values
reported
in
the
original
study
were
reported
as
being
higher
than
the
EC
25
values.
Further
extrapolation
of
the
data
needs
to
be
done
to
derive
EC
05
values
from
the
dose
response
curves
for
the
vegetative
vigor
study.
The
uncertainty
in
these
EC
05
values
will
be
high;
new
data
with
lower
application
rates
which
bracket
observed
EC
25
and
EC
05
levels
would
improve
the
assessment
of
potential
risks
to
nonendangered
and
endangered/
listed
terrestrial
plants.

Results
of
Tier
II
toxicity
tests
with
the
soil
degradate
MCPA
indicate
that
it
also
adversely
affects
seedling
emergence
and
vegetative
vigor
in
monocots
and
dicots.
As
with
MCPB,
onion
was
the
most
sensitive
monocot
tested
with
the
lowest
EC
25
of
0.028
lb
ae/
A
in
the
seedling
emergence
test.
The
most
sensitive
dicot
species
tested
was
cabbage
with
an
EC
25
of
0.008
lb
ae/
A
in
the
seedling
emergence
study.
The
most
sensitive
dicot
in
the
vegetative
vigor
test
were
the
lettuce
and
turnip
with
an
EC
25
of
0.013
lb
ae/
A
(
MRID
43083205).

Terrestrial
Field
Studies
The
requirement
for
terrestrial
field
studies
was
waived.
TABLE
III.
m.
Terrestrial
Non­
target
Plant
Toxicity.*

Seedling
Emergence
Vegetative
Vigor
Shoot
length
Root
weight
Shoot
length
Shoot
weight
Species
EC25/
NOEC
(
lb
ai/
A)
EC25/
NOEC
(
lb
ae/
A)
EC25/

NOEC
(
lb
ai/
A)
EC25/

NOEC
(
lb
ae/
A)
EC25/
NOEC
(
lb
ai/
A)
EC25/
NOEC
(
lb
ae/
A)
EC25/
NOEC
(
lb
ai/
A)
EC25/
NOEC
(
lb
ae/
A)

Monocots
Corn
0.23/
0.19
0.21/
0.17
 
 
 
 
 
 

Oat
0.12/
0.093
0.11/
0.08
 
 
 
 
 
 

Onion
0.021/
0.012
0.02/
0.01
 
 
 
 
0.018/<
0.088
0.016/<
0.08
Ryegrass
0.48/**
0.44/**
 
 
 /
1.3
 /
1.18
 
 

Dicots
Cabbage
0.017/
0.012
0.016/
0.01
 /
0.088
 /
0.080
0.24/­­
0.21/­­
0.0079/­­
0.0072/ 

Cucumber
0.10/
0.093
0.091/
0.085
 
 
0.53/
0.34
0.48/
0.31
 
 

Lettuce
0.059/**
0.054/**
0.027/ 
­­
0.025/ 
0.055/ 
0.050/­­
0.017/**
0.015/**

Radish
0.045/**
0.041/**
 
 
0.22/
0.043
0.20/
0.039
 
 

Soybean
0.13/
0.048
0.12/
0.044
0.14/­­
0.13/­­
0.45/ 
0.41/ 
0.072/**
0.066/**

Tomato
0.17/
0.093
0.15/
0.085
 
­­
0.45/ 
0.41/ 
0.0017/**
0.0015/**

*
MRID
42560804,
Study
author:
K.
Christensen,
1992,
38.9%
active
ingredient.

*
NOEC
reported
in
study
higher
than
EC25.
Further
statistical
analysis
needed
to
establish
EC05
for
endangered
species
assessment.
39
(
Phase
III
3/
07/
06)
    
40
  
147
IV.
RISK
CHARACTERIZATION
Risk
characterization
provides
the
final
step
in
the
risk
assessment
process.
In
this
step,
exposure
and
effects
characterization
are
integrated
to
provide
an
estimate
of
risk
relative
to
established
levels
of
concern
(
LOCs).
The
results
are
then
interpreted
for
the
risk
manager
through
a
risk
description
and
synthesized
into
an
overall
conclusion.

A.
Risk
Estimation
­
Integration
of
Exposure
and
Effects
Data
1.
Non­
target
Aquatic
Animals
and
Plants
Estimated
environmental
concentrations
(
EECs)
from
ground
and
aerial
spray
scenarios
were
calculated
using
the
PRZM
3.12/
EXAMS
2.98
Oregon
snap
bean
scenario
and
California
lettuce
scenario.
As
described
in
the
exposure
characterization,
the
input
parameters
were
adjusted
to
account
for
degradates
MCPA
and
CHPA­
hexose,
which
accounted
for
a
maximum
of
6
­
7%
of
MCPB
in
the
aerobic
soil
metabolism
study.
Since
MCPA
has
been
shown
to
be
less
toxic
to
aquatic
organisms
than
parent
MCPB,
and
the
toxicity
of
CHPA­
hexose
is
not
known,
the
inclusion
of
these
residues
in
the
aquatic
exposure
modeling
may
be
a
conservative
assumption.

Fish
and
Invertebrates
For
ground
and
aerial
spray
scenarios
using
the
PRZM
3.12/
EXAMS
2.98
Oregon
snap
bean
scenario
and
California
lettuce
scenario,
the
aquatic
Acute
Risk,
Acute
Restricted
Use,
and
Endangered
Species
LOCs
were
not
exceeded
for
freshwater
fish
and
invertebrates
with
the
assumption
of
the
maximum
estimated
concentration
of
MCPB
acid
in
the
water
body
under
consideration.
Table
IV.
a.
has
summarized
the
risk
quotients
for
freshwater
fish
and
invertebrates
with
Oregon
and
California
PRZM
3.12/
EXAMS
2.98
scenarios.

TABLE
IV.
a.
Summarized
Acute
Aquatic
Organism
Risk
Quotients
for
MCPB
Acida,
b,
c,
d
Application/
Scenario
Freshwat
er
Fish
Freshwater
Invertebrates
Peas
(
ground
spray
application)
Oregon
<
0.01
<
0.01
Peas
(
aerial
spray
application)
Oregon
<
0.01
<
0.01
Peas
(
ground
spray
application)
California
0.01
<.
0.01
Peas
(
aerial
spray
application)
California
0.01
<
0.01
a
Detailed
calculations
of
PRZM
3.12/
EXAMS
2.98
modeling
for
peas
grown
in
Oregon
and
California
are
provided
in
Appendix
B.

b
Acute
toxicity
thresholds
(
LC50
or
EC50)
were
3.9
and
50
mg
ae/
L
for
freshwater
fish
and
freshwater
invertebrates,
respectively.

C
EECs
for
Oregon
bean
Scenario
were
29.7
and
33.4
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.
DEECs
for
California
lettuce
Scenario
were
40.6
and
43.4
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.
(
Phase
III
3/
07/
06)
    
41
  
147
Chronic
risk
to
freshwater
and
estuarine
marine
fish
and
invertebrates
cannot
be
assessed
because
chronic
toxicity
data
have
not
been
submitted.

Aquatic
Plants
For
MCPB
acid
runoff/
drift,
there
were
no
exceedances
of
the
non­
endangered
Acute
Risk
LOC
for
the
pea
scenarios
that
were
modeled
(
Table
IV.
b.).
However,
the
LOCs
for
endangered
freshwater
vascular
plants
could
not
be
assessed
due
to
a
non­
discreet
NOEC
value.

TABLE
IV.
b.
Summarized
Acute
Aquatic
Plant
Risk
Quotients
for
MCPB
Acid
Non­
endangered
Application/
Scenario
Endangere
d
freshwater
vascular
Freshwater
vascular
Freshwater
non­
vascular
Peas
(
ground
spray
application)
Oregon
N/
A
0.14
0.08
Peas
(
aerial
spray
application)
Oregon
N/
A
0.16
0.09
Peas
(
ground
spray
application)
California
N/
A
0.19
0.10
Peas
(
aerial
spray
application)
California
N/
A
0.21
0.11
2.
Non­
target
Terrestrial
Animals
and
Plants
The
following
Table
IV.
c.
summarizes
the
endpoints
used
in
this
assessment
for
RQ
evaluation
for
non­
target
terrestrial
animals
and
plants:

TABLE
IV.
c.
Summary
of
endpoints
for
MCPB
acute
terrestrial
toxicity
studies
for
RQ
evaluationa
Species
toxicity
value
used
in
risk
assessment
in
ae
MRID#

bird
(
oral
gavage
dose),
LD
50
,
mg
ae/
kg­
bw
257
42560801
mammal,
LD
50
,
mg
ae/
kg­
bw
832
116340
honey
bee,
LD
50
,
µ
g
ae/
bee
23
42532607
(
Phase
III
3/
07/
06)
    
42
  
147
terrestrial
monocots
emergence,
EC
25
,
lbs
ae/
ac
0.02
42560804
terrestrial
dicots
emergence,
EC
25
,
lbs
ae/
ac
0.016
42560804
terrestrial
monocots
vegetative
vigor,
EC
25
,
lbs
ae/
ac
0.018
42560804
terrestrial
dicots
vegetative
vigor,
EC
25
,
lbs
ae/
ac
0.0017
42560804
a
Details
for
each
study
are
presented
in
earlier
sections
of
this
document
and
in
Appendix
F.

Birds
Acute
avian
RQs
were
calculated
using
the
oral
gavage
study
with
bobwhite
quail,
which
resulted
in
a
14­
day
LD
50
of
257
mg
ae/
kg­
bw
(
MRID
42560801).
Assuming
the
maximum
application
rate
(
1.5
lbs
ae/
acre)
and
maximum
predicted
residue
levels,
acute
risk,
acute
restricted
use
and
endangered
species
LOCs
were
exceeded
for
20
g
and
100g
birds.
Acute
restricted
use
and
endangered
species
LOCs
were
exceeded
for
1000g
birds.

As
shown
in
Table
IV.
d.,
the
acute
LOC
is
exceeded
for
20
g
and
100
g
birds
for
short
grass
and
broadleaf
forage
and
small
insect
feed
items.
The
acute
LOC
is
also
exceeded
for
20
g
birds
for
tall
grass
feed,
and
nearly
so
for
100
g
birds.
The
endangered
species
LOC
is
exceeded
for
all
weight
classes
for
short
grass,
broadleaf
forage
and
small
insects,
and
tall
grass
feed
items.
The
endangered
species
LOC
is
also
exceeded
for
20
g
birds
consuming
fruits,
pods,
seeds,
and
large
insects.
The
endangered
species
LOC
is
exceeded
for
short
grass
even
if
mean
residues
are
considered.

RQs
were
not
calculated
based
on
the
acute
dietary
studies
because
no
mortalities
occurred
at
the
highest
concentration
tested
(
LC
50
>
4550
mg
ae/
kg­
diet).
In
addition,
the
data
evaluation
records
noted
inconsistencies
in
the
reporting
of
the
measured
concentrations
of
the
chemical
in
the
diet.
Because
of
the
lack
of
mortality
in
the
acute
dietary
study,
there
is
some
uncertainty
in
the
overall
finding
of
potential
acute
risk
to
birds.

TABLE
IV.
d.
Avian
Acute
Risk
Quotient
Summary
a,
b,
c,
d
1.5
lbs
ae/
acre
Acute
RQd
Food
type
Weight
class
(
g)
predicted
maximum
residues
predicted
mean
residues
short
grass
20
2.26***
0.80***
(
Phase
III
3/
07/
06)
    
43
  
147
100
1.01***
0.36**

1000
0.32**
0.11*

20
1.03***
0.34**

100
0.46**
0.15*

tall
grass
1000
0.15*
0.05
20
1.27***
0.42**

100
0.57***
0.19*

broadleaf
forage,
small
insects
1000
0.18*
0.06
20
0.14*
0.07
100
0.06
0.03
fruit,
pods,
seeds,
large
insects
1000
0.02
0.01
RQ
values
are
dose
base
calculations
*
indicates
an
exceedance
of
Endangered
Species
Level
of
Concern
(
LOC);
RQ
>
0.10.
**
indicates
an
exceedance
of
Acute
Restricted
Use
LOC;
RQ
>
0.20.
***
indicates
an
exceedance
of
Acute
Risk
LOC;
RQ
>
0.50.

Mammals
To
evaluate
the
acute
risk
to
mammals,
RQs
were
calculated
using
the
minimum
LD
50
obtained
from
the
acute
oral
studies
(
832
mg
ae/
kg­
bwt,
MRID
116340)
at
the
maximum
labeled
rate
of
1.5
lbs
ae/
acre.
To
evaluate
the
chronic
(
developmental/
reproductive)
risk
to
mammals,
RQs
were
calculated
using
the
NOAEL
for
maternal
toxicity
obtained
from
the
rabbit
developmental
toxicity
study
with
MCPB
acid
equivalent
(
NOAEL=
4.56
mg
ae/
kg/
day,
MRID
40865401).
The
exposure
model
T­
REX
is
set
up
to
calculate
RQs
for
the
laboratory
rat,
which
is
the
typical
surrogate
species
for
environmental
risk
assessments.
Because
the
toxicity
study
for
rabbit
was
used
in
this
case,
the
toxicity
values
for
the
rabbit
study
were
adjusted
for
a
3000
g
rabbit
in
T­
REX
model.
The
RQs
are
detailed
in
Tables
IV.
e.
and
IV.
f.
and
they
are
summarized
in
Appendix
F.

Assuming
maximum
residue
levels
at
the
maximum
single
application
rate
(
1.5
lbs
ae/
acre),
the
Acute
Endangered
Species
Risk
LOC
was
exceeded
for
small
mammals
(
15
g
and
35g)
consuming
short
grass
(
RQ
=
0.19
and
0.16,
respectively)
and
for
small
mammals
(
15
g)
consuming
broadleaf
forage
and
small
insects
(
RQ
=
0.11).
Acute
and
acute
restricted
use
LOCs
were
not
exceeded.
There
were
no
exceedences
of
the
risk
LOCs
by
mammals
consuming
foods
at
the
predicted
mean
MCPB
residue
levels.

TABLE
IV.
e.
Mammalian
Acute
Risk
Quotient
Summary
1.5
lbs
ae/
acre
Food
type
Weight
class
(
g)
Predicted
maximum
residues
Predicted
mean
residues
(
Phase
III
3/
07/
06)
    
44
  
147
15
0.19*
0.07
35
0.16*
0.06
short
grass
1000
0.08
0.03
15
0.09
0.03
35
0.07
0.02
tall
grass
1000
0.04
0.01
15
0.11*
0.04
35
0.09
0.03
broadleaf
forage,
small
insects
1000
0.05
0.02
15
0.01
0.01
35
0.01
<
0.01
fruit,
large
insects
1000
0.01
<
0.01
15
<
0.01
<
0.01
35
<
0.01
<
0.01
seeds,
pods
1000
<
0.01
<
0.01
*
indicates
an
exceedance
of
Endangered
Species
Level
of
Concern
(
LOC);
RQ
>
0.10.

Assuming
maximum
and
mean
residue
levels
at
the
maximum
application
rate,
Chronic
Risk
LOCs
were
exceeded
in
all
weight
classes
(
15
g,
35
g,
and
1000g)
of
mammals
for
consumption
of
short
grass,
tall
grass
and
broadleaf
forage/
small
insects.
Assuming
maximum
residue
levels
at
the
maximum
application
rate,
Chronic
Risk
LOCs
were
exceeded
in
15
g
and
35g
mammals
for
consumption
of
fruit
and
large
insects.

TABLE
IV.
f.
Mammalian
Chronic
Risk
Quotient
Summary
1.5
lbs
ae/
acre
Food
type
Weight
class
(
g)
Predicted
maximum
residues
Predicted
mean
residues
15
19.94*
6.44*

35
17.12*
5.53*

short
grass
1000
9.00*
2.91*

15
9.14*
2.73*

35
7.85*
2.34*

tall
grass
1000
4.12*
1.23*

broadleaf
forage,
small
i
15
11.22*
3.41*
(
Phase
III
3/
07/
06)
    
45
  
147
35
9.63*
2.93*

1000
5.06*
1.54*

15
1.25*
0.53
35
1.07*
0.46
fruit,
large
insects
1000
0.56
0.24
15
0.47
0.12
35
0.24
0.1
seeds,
pods
1000
0.11
0.08
*
indicates
an
exceedance
of
Chronic
LOC,
RQ
>
1.0.

Terrestrial
Non­
Target
Insects
EFED
currently
does
not
quantify
risks
to
terrestrial
non­
target
insects;
therefore,
risk
quotients
are
not
calculated
for
these
organisms.
Risks
are
qualitatively
discussed
in
the
Terrestrial
Organism
Risk
Characterization
section
of
this
document.

3.
Non­
target
Terrestrial
Plants
in
Dryland
and
Semi­
aquatic
Areas:
An
analysis
of
the
results
indicates
exceedance
of
the
Acute
Risk
LOC
for
non­
endangered
monocots
and
dicots
in
dryland
and
semi­
aquatic
areas
located
adjacent
to
treated
areas,
both
as
a
result
of
combined
runoff
and
spray
drift,
and
from
spray
drift
alone.
(
Table
IV.
g).
The
Endangered
Species
LOC
was
exceeded
for
monocots
and
dicots
located
adjacent
to
treated
areas
and
in
semi­
aquatic
areas
and
for
dicots
as
a
result
of
spray
drift.
The
most
sensitive
seedling
emergence
EC
25
values
were
0.02
and
0.016
lb
ae/
acre
for
monocots
and
dicots,
respectively.
These
values
are
used
to
calculate
risk
quotients
for
exposure
from
combined
runoff
and
spray
drift
to
adjacent
fields.

Risk
to
terrestrial
plants
from
spray
drift
alone
is
evaluated
by
comparing
the
estimated
exposure
from
drift
to
the
most
sensitive
EC
25
calculated
from
vegetative
vigor
laboratory
tests.
Among
monocot
species
tested,
only
onion
showed
sensitivity
to
MCPB
in
the
vegetative
vigor
test,
with
an
EC
25
of
0.016
a.
e/
acre,
based
on
reductions
in
shoot
weight.
Based
on
this
value,
the
acute
LOC
for
monocots
is
exceeded.
A
NOEC
could
not
be
established
in
this
study,
but
the
exceedence
of
the
LOC
for
nonendangered
plants
indicates
that
risk
to
endangered
and
listed
monocots
is
also
a
concern.
The
fact
that
effects
(
and
therefore
risk)
were
indicated
for
only
one
of
four
monocots
tested
suggests
that
only
a
subset
of
non­
target
monocots
may
be
at
risk.
The
fact
that
monocots
are
not
broadly
sensitive
is
consistent
with
the
fact
that
MCPA
is
an
herbicide
used
to
control
broadleaf
weeds.

Reduction
in
shoot
weight
was
the
most
sensitive
endpoint
for
the
four
most
sensitive
dicots
tested
in
the
vegetative
vigor
study.
However,
the
magnitude
of
the
EC
25
values
is
uncertain
because
they
were
extrapolated
below
the
lowest
dose
tested
in
the
study.
For
instance,
although
the
calculated
EC
25
for
MCPB
on
tomato
is
0.0015
lb
ae/
acre,
the
lowest
application
rate
tested
in
this
study
was
0.08
lb
ai/
acre.
Similarly,
the
EC
25
of
(
Phase
III
3/
07/
06)
    
46
  
147
0.015
for
lettuce
was
extrapolated
below
the
lowest
application
rate
of
0.039.
Based
on
these
EC
25
values,
however,
the
RQs
exceed
the
level
of
concern.

Because
RQs
based
on
the
EC
25
values
exceed
the
acute
LOC,
and
exposure
can
be
expected
which
would
cause
greater
than
a
25%
effect,
risk
to
endangered
plants
is
also
a
concern.
However,
risk
quotients
with
which
to
evaluate
risk
from
spray
drift
to
endangered
plants
were
not
calculated
because
the
NOEC
values
in
the
vegetative
vigor
study
for
the
dicots
were
reported
as
being
higher
than
the
EC
25
values.
A
NOEC
could
not
be
determined
for
onion,
the
only
monocot
tested
which
was
sensitive
to
MCPB.
Therefore,
a
RQ
could
not
be
derived
for
comparison
to
the
endangered
species
LOC.

Further
extrapolation
of
the
data
needs
to
be
done
to
derive
EC
05
values
from
the
dose
response
curves
for
the
vegetative
vigor
study.
The
uncertainty
in
these
EC
05
values
will
be
high;
new
data
with
lower
application
rates
which
bracket
observed
EC
25
and
EC
05
levels
would
improve
the
assessment
of
potential
risks
to
nonendangered
and
endangered/
listed
terrestrial
plants.

Detailed
calculations
for
plant
risk
quotients
are
presented
in
Appendix
F.

TABLE
IV.
g.
Summarized
Terrestrial
Plant
Risk
Quotients
Acute
Non­
endangered
RQs
Acute
Endangered
RQs
Scenari
o
Adjacent
to
treated
sites
Semiaquatic
areas
Drift
Adjacent
to
treated
sites
Semiaquatic
areas
Drift
Ground
spray
application
(
1.5
lbs
ae/
acre)

Monocot
4.50***
38.25***
0.94
9.00*
76.50*
­­

Dicot
5.63***
47.81***
2.08***
9.00*
76.50*
­­

Aerial
spray
application
(
1.5
lbs
ae/
acre)

Monocot
6.00***
26.25***
4.69***
12.00*
52.50*
­­

Dicot
7.50***
32.81***
10.42***
12.00*
52.50*
­­

*
indicates
an
exceedance
of
the
Endangered
Species
Level
of
Concern
(
LOC).
***
indicates
an
exceedance
of
the
Acute
Risk
LOC.

B.
Risk
Description
1.
Risks
to
Aquatic
Organisms:
In
the
conceptual
model,
spray
drift
and
runoff
to
adjacent
bodies
of
water
were
predicted
as
the
most
likely
sources
of
MCPB
and
MCPB
sodium
exposure
to
nontarget
aquatic
organisms.

Fish
and
Invertebrates
Based
on
acute
risk
quotients
below
the
levels
of
concern,
freshwater
fish
and
invertebrates
inhabiting
surface
waters
adjacent
to
MCPB
treated
fields
do
not
appear
to
(
Phase
III
3/
07/
06)
    
47
  
147
be
at
risk
for
adverse
acute
effects
on
growth
and
survival.
Toxicity
studies
are
not
available
to
determine
the
potential
chronic
effects
to
fish
and
invertebrates
and
acute
risks
to
estuarine
marine
fish
and
estuarine
marine
invertebrates.
Therefore,
a
complete
risk
assessment
cannot
be
done
for
fish
and
invertebrates,
and
it
is
not
possible
to
certify
that
MCPB
use
is
 
not
likely
to
adversely
affect 
listed
fish
and
invertebrates.

Aquatic
Plants
Toxicity
studies
with
aquatic
plant
species
indicate
that
exposure
to
MCPB
results
in
significantly
adverse
effects
to
growth
and
development.
The
EC
50
for
the
freshwater
vascular
plant
(
duckweed)
is
0.21
mg
ae/
L,
based
on
reduced
frond
production;
and
the
lowest
EC
50
for
the
freshwater
non­
vascular
plant
(
green
algae)
is
0.38
mg
ae/
L,
based
on
reduced
cell
density.
Concentrations
as
low
as
0.13
mg
ae/
L
resulted
in
chlorosis,
curling,
and
decreased
root
formation
in
the
aquatic
vascular
plant,
duckweed.
In
addition,
frond
biomass
was
significantly
reduced
at
0.42
mg
ae/
L.

For
MCPB
acid
runoff/
drift,
there
were
no
exceedances
of
the
non­
endangered
Acute
Risk
LOC
for
the
pea
scenarios
that
were
modeled
(
Table
IV.
b.).
However,
it
is
not
possible
to
calculate
risk
quotients
to
compare
to
the
endangered
species
LOC,
since
a
definitive
NOEC
was
not
determined
for
duckweed
and
green
algae.

2.
Risks
to
Terrestrial
Organisms:
In
the
conceptual
model,
ground
deposition
and
spray
drift
with
resulting
residues
on
foliage,
on
flowers
and
seeds,
and
soil
invertebrates
were
predicted
as
the
most
likely
sources
of
MCPB
and
MCPB
sodium
exposure
to
nontarget
terrestrial
organisms.
An
additional
predicted
source
of
exposure
to
MCPB
sodium
was
in
puddled
water
on
treated
fields
through
preening
and
grooming,
involving
the
oral
ingestion
of
material
from
the
feathers
or
fur.

Risks
to
terrestrial
organisms
(
i.
e.
birds,
mammals,
and
plants)
were
assessed
based
on
modeled
Estimated
Environmental
Concentrations
(
EECs)
and
available
toxicity
data.
As
part
of
the
terrestrial
assessment,
EFED
modeled
exposure
concentrations
of
MCPB
to
nontarget
terrestrial
plants
and
animals
following
the
proposed
application
rates
provided
by
the
registrant.
For
terrestrial
birds
and
mammals,
estimates
of
initial
levels
of
MCPB
residues
on
various
food
items,
which
may
be
contacted
or
consumed
by
wildlife,
were
determined
using
the
Kenega­
Fletcher
nomogram
followed
by
a
first
order
decline
model
TREX
1.1.
Likewise,
the
TerrPlant
1.0
model
estimated
exposure
to
nontarget
plants
and
the
AgDrift
2.0.1
model
provided
further
refinement
of
spray
drift
dispersion
and
deposition
to
terrestrial
plants
located
in
proximity
to
treated
fields.

Birds
MCPB
is
categorized
as
moderately
toxic
to
avian
species
on
an
acute
oral
basis
(
14­
day
LD
50
257
mg
ae/
kg);
but
is
practically
non­
toxic
to
avian
species
on
an
acute
dietary
basis
(
8­
day
LD
50
>
4,550
ppm
ae).
In
the
oral
study,
the
bobwhite
quail
exhibited
sublethal
effects;
including
reduced
body
weight
gain
(
dietary
exposure),
lethargy,
dyspnea,
loss
of
righting
reflex
and
diarrhea.
Gross
necropsy
of
birds
in
both
the
oral
gavage
and
dietary
studies
showed
white
areas/
film
on
(
Phase
III
3/
07/
06)
    
48
  
147
the
heart,
liver
(
dietary
exposure),
gizzard,
gallbladder,
crop
or
intestines.
The
8­
day
NOELs
for
each
species
in
the
dietary
study,
based
on
sublethal
effects
(
reduced
body
weight
gain),
were
1138
ppm
ae.

Based
on
these
acute
toxicity
data,
there
is
a
large
differential
in
the
acute
lethality
when
MCPB
is
administered
as
a
single
gavage
or
when
mixed
in
the
feed.
However,
there
are
limitations
to
both
the
dose­
based
and
dietary­
based
method
of
calculating
risk
quotients.
The
dose­
based
approach
assumes
that
the
uptake
and
absorption
kinetics
of
a
gavage
toxicity
study
approximate
the
absorption
associated
with
uptake
from
a
dietary
matrix.
Toxic
response
is
a
function
of
duration
and
intensity
of
exposure
and
the
importance
of
absorption
kinetics
across
the
gut
and
enzymatic
activation/
deactivation
of
a
toxicant
may
be
important
and
are
likely
to
be
variable
across
chemicals
and
species.

For
many
compounds
a
gavage
dose
represents
a
very
short­
term
high
intensity
exposure,
whereas
dietary
exposure
may
be
of
a
more
prolonged
nature.
The
dietary
approach
assumes
that
animals
in
the
field
are
consuming
food
at
a
rate
similar
to
that
of
confined
laboratory
animals.
The
strength
of
this
assumption
is
uncertain,
because
energy
content
in
food
items
differs
between
the
field
and
in
the
laboratory,
as
do
the
energy
requirements
of
wild
and
captive
animals.

In
any
case,
because
sublethal
effects
were
observed
in
both
studies,
including
the
dietary
study
at
doses
>
569
ppm
ae,
sublethal
risks
to
avian
species
using
the
treated
fields
or
inhabiting
adjacent
edge
or
riparian
communities
could
result
from
the
labeled
use
of
MCPB.

Avian
reproduction
studies
using
the
TGAI
are
usually
required
for
pesticide
registration
because
birds
may
be
subject
to
repeated
or
continuous
exposure
to
the
pesticide,
especially
preceding
or
during
the
breeding
season.
The
preferred
test
species
are
mallard
duck
and
bobwhite
quail.
No
chronic
bird
studies
were
submitted
for
MCPB.
EFED
considered
MCPA
as
a
substitute
for
MCPB
for
chronic
risk
to
birds,
because
the
LD50
for
bobwhite
quail
suggests
that
the
acute
potency
of
MCPB
lies
within
the
range
of
toxicity
for
acid
equivalent
MCPA.
Also,
rapid
dissociation
of
MCPB
to
MCPA
is
expected
to
occur
in
the
bird
gut
due
to
the
chemical
properties
of
MCPB.
The
chronic
bird
study
for
MCPA
with
bobwhite
quail
has
a
NOAEC
of
1000
mg/
kg­
diet
(
MRID
#
435052­
01)
.
No
further
studies
are
required
for
chronic
risk
to
birds
for
MCPB
at
this
time.

Mammals
MCPB
is
classified
as
slightly
toxic
to
practically
non­
toxic
to
small
mammals
on
an
acute
oral
basis
(
LD
50
values
range
from
912
­
7,400
mg
ai/
kg/
day).
(
Phase
III
3/
07/
06)
    
49
  
147
Reproductive
effects
were
observed
in
dogs
at
44
mg
ai/
kg/
day
based
on
reduced
testes
weights
and
physiological
changes
in
clinical
chemistry.
In
developmental
studies
with
rats
and
rabbits,
maternal
toxicity
was
observed
at
doses
ranging
from
20
­
100
mg
ai/
kg/
day.
In
the
rat
study,
the
maternal
toxicity
observed
at
100
mg
ai/
kg/
day
included
decreased
body
weights
and
body
weight
gains
during
gestation.
In
the
rabbit
study,
maternal
toxicity
observed
at
20
mg
ai/
kg/
day
included
maternal
deaths,
clinical
signs
of
toxicity,
decrease
in
body
weight
gain
during
treatment,
and
change
in
color
of
liver
and
kidneys.
The
maternal
toxicity
NOAEL
for
this
study
was
5
mg
ai/
kg/
day.
Developmental
effects
were
observed
in
rats
at
a
dose
of
100
mg/
kg/
day,
including
decreased
mean
body
weights/
litter
for
males
and
females,
increases
in
unossified
or
poorly
ossified
sites
and
increases
in
several
other
skeletal
variations.

The
risk
assessment
and
calculated
RQs
assume
100%
of
the
diet
is
relegated
to
single
food
types
foraged
only
from
treated
fields.
However,
because
the
Chronic
LOCs
are
exceeded
for
multiple
food
categories,
potential
exposure
may
still
be
high
enough
to
warrant
concern.
Other
exposure
routes
are
possible
for
animals
residing
in
or
moving
through
treated
areas.
Ingestion
of
contaminated
soils,
dermal
contact,
and
inhalation
are
not
considered
in
this
screening
assessment,
and
represent
potential
routes
of
exposure.
Consumption
of
drinking
water
would
appear
to
be
inconsequential
if
water
concentrations
were
equivalent
to
the
concentrations
from
PRZM/
EXAMS;
however,
concentrations
in
puddled
water
sources
on
treated
fields
may
be
higher
than
concentrations
in
modeled
ponds.
Preening
and
grooming
exposures,
involving
the
oral
ingestion
of
material
from
the
feathers
or
fur
remains
an
unquantified,
but
potentially
important,
exposure
route.
Consequently;
based
on
these
results,
mammals
may
be
subject
to
developmental/
reproductive
effects
and
direct
effects
on
foraging
behavior
when
chronically
exposed
to
MCPB
as
a
result
of
the
labeled
use
of
the
herbicide.

Based
on
possible
endocrine­
related
effects
related
to
mammals
(
via
reproductive
effects)
MRID
116345
and
MRID
42883603,
MCPB
may
be
classified
as
a
potential
endocrine
disruptor.
EPA
is
required
under
the
Federal
Food,
Drug,
and
Cosmetic
Act
(
FFDCA),
as
amended
by
the
Food
Quality
Protection
Act
(
FQPA),
to
develop
a
screening
program
to
determine
whether
certain
substances
(
including
all
pesticide
active
and
other
ingredients)
 
may
have
an
effect
in
humans
that
is
similar
to
an
effect
produced
by
a
naturally
occurring
estrogen,
or
other
such
endocrine
effects
as
the
Administrator
may
designate. 
Following
the
recommendations
of
its
Endocrine
Disruptor
Screening
and
Testing
Advisory
Committee
(
EDSTAC),
EPA
determined
that
there
was
a
scientific
basis
for
including,
as
part
of
the
program,
the
androgen
and
thyroid
hormone
systems,
in
addition
to
the
estrogen
hormone
system.
EPA
also
adopted
EDSTAC s
recommendation
that
the
Program
include
evaluations
of
potential
effects
in
wildlife.
For
pesticide
chemicals,
EPA
will
use
the
Federal
Insecticide,
Fungicide,
and
Rodenticide
Act
(
FIFRA)
and,
to
the
extent
that
effects
in
wildlife
may
help
determine
whether
a
substance
may
have
an
effect
in
humans,
FFDCA
authority
to
require
the
wildlife
evaluations.
As
the
science
develops
and
resources
allow,
screening
of
additional
hormone
systems
may
be
added
to
the
Endocrine
Disruptor
Screening
Program
(
EDSP).
When
the
appropriate
screening
and/
or
testing
protocols
being
considered
under
the
(
Phase
III
3/
07/
06)
    
50
  
147
Agency s
EDSP
have
been
developed,
MCPB
may
be
subjected
to
additional
screening
and/
or
testing
to
better
characterize
effects
related
to
endocrine
disruption.

Terrestrial
Non­
target
Insects
EFED
currently
does
not
quantify
risks
to
terrestrial
non­
target
insects.
Risk
quotients
are
therefore
not
calculated
for
these
organisms.
MCPB
was
practically
non­
toxic
to
honey
bees
(
LD
50
of
>
23
µ
g
ae/
bee)
in
an
acute
contact
study,
but
potential
exposure
has
not
been
quantified.

Terrestrial
Plants
in
Dryland
and
Semi­
aquatic
Areas
An
analysis
of
the
results
indicates
exceedance
of
the
Acute
Risk
LOC
for
nonendangered
monocots
and
dicots
located
adjacent
to
treated
areas,
in
semiaquatic
areas,
and
as
a
result
of
spray
drift.
(
Table
IV.
g).
The
Endangered
Species
LOC
was
exceeded
for
monocots
and
dicots
located
in
dryland
and
semi­
aquatic
areas
adjacent
to
treated
areas
and
for
dicots
as
a
result
of
spray
drift.
The
potential
risk
to
endangered
terrestrial
plants
will
be
discussed
in
greater
detail
in
Section
IV.
B.
4.

In
spite
of
the
uncertainty
in
the
magnitude
of
the
EC
25
values
used
to
calculate
the
RQs
for
MCPB,
other
data
in
the
vegetative
vigor
studies
indicate
the
potential
for
risk
to
non­
target
dicots
from
spray
drift
alone.
Using
the
spray
drift
model
AgDrift,
the
distances
were
calculated
at
which
exposure
would
be
equivalent
to
the
lowest
application
rates
tested
in
the
vegetative
vigor
study
which
led
to
adverse
effects.
This
Tier
1
AgDrift
assessment
assumed
a
fine
to
medium
droplet
size
spectrum,
and
an
aerial
application.
Table
IV.
h.
shows
these
rates
for
each
crop,
the
level
of
effect
seen
at
that
rate,
and
the
distance
at
which
that
deposition
would
occur.

TABLE
IV.
h.
­
Distance
of
Deposition
of
MCPB
Equivalent
to
Rates
Tested
in
Vegetative
Vigor
Study
Crop
Lowest
Rate
Tested
with
Adverse
Effect
(
lb
ae/
acre)
%
Effect
to
Shoot
Weight
at
that
Rate
Distance
of
Deposition
at
that
Rate
(
ft)

Cabbage
0.08
49
177
Lettuce
0.039
26
361
Soybean
0.17
53
85
Tomato
0.08
43
177
Highly
active
herbicides,
such
as
the
growth
regulators,
present
the
greatest
drift
hazard
because
extremely
small
amounts
can
cause
severe
problems.
Even
if
only
a
small
surface
area
of
the
plant
is
exposed
to
MCPB,
or
a
seedling
is
exposed
to
MCPB
as
it
breaks
through
the
soil
surface,
there
is
a
possibility
that
the
plant
may
be
severely
damaged
or
die
as
a
result.
In
the
vegetative
vigor
test,
effects
observed
included
mortality
(
one
cucmber
plant,
two
radish
plants),
leaf
necrosis,
decreased
plant
size,
leaf
curl,
and
stem
tumors.
Such
damage,
even
if
only
minor,
(
Phase
III
3/
07/
06)
    
51
  
147
may
be
sufficient
to
prevent
the
plant
from
competing
successfully
with
other
plants
for
resources
and
water.

Currently,
the
labels
for
the
registered
MCPB
herbicides
do
not
place
restrictions
on
droplet
size
or
wind
speed
during
application.
The
exception
is
the
state
of
Florida,
which
has
promulgated
a
rule
(
Organo­
Auxin
Herbicide
Rule)
that
stipulates
that
buffer
zones
up
to
a
half­
mile
wide
be
observed
when
spraying
phenoxy
herbicides.
The
width
of
the
required
buffer
zone
is
dependent
on
the
wind
speed
and
direction,
and
whether
aerial
or
ground
spray
equipment
is
used.
This
has
the
potential
to
reduce
the
exposure
susceptible
non­
target
plants
to
spray
drift.
However,
since
the
vegetative
vigor
tests
could
not
determine
a
noeffect
application
rate
for
MCPB,
the
effectiveness
of
these
buffers
to
eliminate
risk
to
plants
cannot
be
evaluated.

Direct
effects
to
plant
species
could
result
in
indirect
effects
at
the
higher
levels
of
organization
(
i.
e.
population,
trophic
level,
community,
ecosystem).
In
terrestrial
and
shallow­
water
aquatic
communities,
plants
are
the
primary
producers
upon
which
the
succeeding
trophic
levels
depend.
If
the
available
plant
material
is
impacted
due
to
the
effects
of
MCPB
and
MCPB
sodium,
this
may
have
negative
effects
not
only
on
the
herbivores,
but
throughout
the
food
chain.
Also,
depending
on
the
severity
of
impacts
to
the
plant
communities
(
edge
and
riparian
vegetation),
community
assemblages
and
ecosystem
stability
may
be
altered
(
i.
e.
reduced
bird
populations
in
edge
habitats;
reduced
riparian
vegetation
resulting
in
increased
light
penetration
and
temperature
in
aquatic
habitats).
Furthermore,
reduction
of
upstream
riparian
vegetation
that
would
otherwise
supply
downstream
habitats
could
result
not
only
in
a
loss
of
a
significant
component
of
food
for
aquatic
herbivores
and
detritivores,
but
also
of
habitat
(
i.
e.
leaf
packs,
materials
for
case­
building
for
invertebrates).
The
assessment
of
risk
to
aquatic
receptors
will
focus
on
freshwater
systems
and
exclude
saltwater/
estuarine
systems
based
on
the
regional
use
patterns
of
the
herbicide.
Field
studies
are
not
available
to
quantify
actual
risk
to
plant
and
animal
communities
in
edge
and
riparian
habitats;
however,
the
potential
for
adverse
effects
may
occur.

3.
Review
of
Incident
Data:
FIFRA
6(
a)(
2)
incident
data
add
lines
of
evidence
to
provide
evidence
that
the
risk
predictions
from
the
screening
level
assessment
are
substantiated
with
actual
effects
in
the
field.
No
aquatic
or
terrestrial
incidents
have
been
reported
to
the
Agency
for
MCPB
as
of
March
1,
2005.
The
lack
of
reported
incidents
cannot
be
considered
as
evidence
of
lack
of
hazard.
Incident
reporting
is
a
voluntary
process.
At
the
present
time,
the
lack
of
mortality
incidents
in
the
Ecological
Incident
Information
System
(
EIIS)
database
cannot
be
considered
as
evidence
of
a
lack
of
hazard
to
aquatic
and/
or
terrestrial
organisms.

4.
Federally
Threatened
and
Endangered
(
Listed)
Species
Concerns
Action
Area
(
Phase
III
3/
07/
06)
    
52
  
147
For
listed
species
assessment
purposes,
the
action
area
is
considered
to
be
the
area
affected
directly
or
indirectly
by
the
Federal
action
and
not
merely
the
immediate
area
involved
in
the
action.
At
the
initial
screening­
level,
the
risk
assessment
considers
broadly
described
taxonomic
groups
and
so
conservatively
assumes
that
listed
species
within
those
broad
groups
are
collocated
with
the
pesticide
treatment
area.
This
means
that
terrestrial
plants
and
wildlife
are
assumed
to
be
located
on
or
adjacent
to
the
treated
site
and
aquatic
organisms
are
assumed
to
be
located
in
a
surface
water
body
adjacent
to
the
treated
site.
The
assessment
also
assumes
that
the
listed
species
are
located
within
an
assumed
area
which
has
the
relatively
highest
potential
exposure
to
the
pesticide,
and
that
exposures
are
likely
to
decrease
with
distance
from
the
treatment
area.
Section
II.
A.
4.
of
this
risk
assessment
presents
the
pesticide
use
sites
that
are
used
to
establish
initial
collocation
of
species
with
treatment
areas.

If
the
assumptions
associated
with
the
screening­
level
action
area
result
in
RQs
that
are
below
the
listed
species
LOCs,
direct
effects
to
listed
species
are
not
expected
for
that
taxon.
Furthermore,
RQs
below
the
listed
species
LOCs
for
a
given
taxonomic
group
indicate
no
concern
for
indirect
effects
upon
listed
species
that
depend
upon
the
taxonomic
group
covered
by
the
RQ
as
a
resource.
However,
in
situations
where
the
screening
assumptions
lead
to
RQs
in
excess
of
the
listed
species
LOCs
for
a
given
taxonomic
group,
a
potential
for
a
"
may
affect"
conclusion
exists
and
may
be
associated
with
direct
effects
on
listed
species
belonging
to
that
taxonomic
group
or
may
extend
to
indirect
effects
upon
listed
species
that
depend
upon
that
taxonomic
group
as
a
resource.
In
addition,
if
no
toxicity
data
are
available
on
which
to
calculate
RQs,
then
risk
to
listed
species
in
a
particular
taxon
cannot
be
dismissed.

If
it
is
not
possible
to
come
to
a
 
not
likely
to
adversely
affect 
conclusion,
additional
information
on
the
biology
of
listed
species,
the
locations
of
these
species,
and
the
locations
of
use
sites
could
be
considered
along
with
available
information
on
the
fate
and
transport
properties
of
the
pesticide
to
determine
the
extent
to
which
screening
assumptions
regarding
an
action
area
apply
to
a
particular
listed
organism.
These
subsequent
refinement
steps
could
consider
how
this
information
would
impact
the
action
area
for
a
particular
listed
organism
and
may
potentially
include
areas
of
exposure
that
are
downwind
and
downstream
of
the
pesticide
use
site.

Taxonomic
Groups
Potentially
at
Risk
The
preliminary
risk
assessment
for
endangered
species
indicates
that
MCPB
exceeds
the
Endangered
Species
LOCs
for
the
single
application
per
year
for
peas
with
an
application
rate
of
1.5
lbs
ae/
acre:
·
freshwater
vascular
plants
·
small
(
20g),
medium
(
100
g)
and
large
birds
(
1000
g)
feeding
on
short
grass,
tall
grass,
and
broadleaf
forage/
small
insects;
small
birds
feeding
on
fruit,
pods,
seeds,
and
large
insects
·
(
15
and
35
g)
mammals
feeding
on
short
grass;
small
mammals
(
15
g)
feeding
on
broadleaf
forage/
small
insects.
(
Phase
III
3/
07/
06)
    
53
  
147
·
non­
target
terrestrial
plants
­
monocots
and
dicots
adjacent
to
treated
areas
and
semi­
aquatic.

Discussion
of
Risk
Quotients
The
Agency s
LOC
for
listed
freshwater
vascular
plants,
birds,
mammals,
and
nontarget
terrestrial
plants
is
exceeded
for
the
use
of
MCPB
as
outlined
in
previous
sections.
Should
estimated
exposure
levels
occur
in
proximity
to
listed
resources,
the
available
screening
level
information
suggests
a
potential
concern
for
direct
effects
on
listed
species
within
these
taxonomic
groups
listed
above
associated
with
the
use
of
MCPB
as
described
in
Section
II.
A.
4.
The
registrant
must
provide
information
on
the
proximity
of
Federally
listed
freshwater
vascular
plants,
small
and
large
birds,
small
mammals,
and
non­
target
terrestrial
plants
to
the
MCPB
use
sites.
This
requirement
may
be
satisfied
in
one
of
three
ways:
1)
having
membership
in
the
FIFRA
Endangered
Species
Task
Force
(
Pesticide
Registration
[
PR]
Notice
2000­
2);
2)
citing
FIFRA
Endangered
Species
Task
Force
data;
or
3)
independently
producing
these
data,
provided
the
information
is
of
sufficient
quality
to
meet
FIFRA
requirements.
The
information
will
be
used
by
the
OPP
Endangered
Species
Protection
Program
to
develop
recommendations
to
avoid
adverse
effects
to
listed
species.

Use
of
Probit
Slope
Response
Relationship
to
Provide
Information
on
the
Endangered
Species
Levels
of
Concern
The
Agency
uses
the
probit
dose
response
relationship
as
a
tool
for
providing
additional
information
on
the
listed
animal
species
acute
levels
of
concern.
The
acute
listed
species
LOCs
of
0.1
and
0.05
are
used
for
terrestrial
and
aquatic
animals,
respectively.
As
part
of
the
risk
characterization,
an
interpretation
of
acute
LOCs
for
listed
species
is
discussed.
This
interpretation
is
presented
in
terms
of
the
chance
of
an
individual
event
(
i.
e.,
mortality
or
immobilization)
should
exposure
at
the
estimated
environmental
concentration
actually
occur
for
a
species
with
sensitivity
to
difenoconazole
on
par
with
the
acute
toxicity
endpoint
selected
for
RQ
calculation.
To
accomplish
this
interpretation,
the
Agency
uses
the
slope
of
the
dose
response
relationship
available
from
the
toxicity
study
used
to
establish
the
acute
toxicity
measurement
endpoints
for
each
taxonomic
group.
The
individual
effects
probability
associated
with
the
LOCs
is
based
on
the
mean
estimate
of
the
slope
and
an
assumption
of
a
probit
dose
response
relationship.
In
addition
to
a
single
effects
probability
estimate
based
on
the
mean,
upper
and
lower
estimates
of
the
effects
probability
are
also
provided
to
account
for
variance
in
the
slope.
The
upper
and
lower
bounds
of
the
effects
probability
are
based
on
available
information
on
the
95%
confidence
interval
of
the
slope.
A
statement
regarding
the
confidence
in
the
applicability
of
the
assumed
probit
dose
response
relationship
for
predicting
individual
event
probabilities
is
also
included.
Studies
with
good
probit
fit
characteristics
(
i.
e.,
statistically
appropriate
for
the
data
set)
are
associated
with
a
high
degree
of
confidence.
Conversely,
a
low
degree
of
confidence
is
associated
with
data
from
studies
that
do
not
statistically
support
a
probit
dose
response
relationship.
In
addition,
confidence
in
the
data
set
may
be
reduced
by
high
variance
in
the
slope
(
i.
e.,
large
95%
confidence
intervals),
despite
good
probit
fit
characteristics.
(
Phase
III
3/
07/
06)
    
54
  
147
Individual
effect
probabilities
are
calculated
based
on
an
Excel
spreadsheet
tool
IECV1.1
(
Individual
Effect
Chance
Model
Version
1.1)
developed
by
the
U.
S.
EPA,
OPP,
Environmental
Fate
and
Effects
Division
(
June
22,
2004).
The
model
allows
for
such
calculations
by
entering
the
mean
slope
estimate
(
and
the
95%
confidence
bounds
of
that
estimate)
as
the
slope
parameter
for
the
spreadsheet.
In
addition,
the
LOC
(
0.1
for
terrestrial
animals
and
0.05
for
aquatic
animals)
is
entered
as
the
desired
threshold.

Probit
Slope
Analysis
The
probit
slope
response
relationship
is
evaluated
to
calculate
the
change
of
an
individual
event
corresponding
to
the
listed
species
acute
LOCs.
If
information
is
unavailable
to
estimate
a
slope
for
a
particular
study,
a
default
slope
assumption
of
4.5
is
used
as
per
original
Agency
assumptions
of
typical
slope
cited
in
Urban
and
Cook
(
1986).

Freshwater
Fish
The
following
calculations
were
calculated
by
the
probit
method.
Analysis
of
raw
data
from
the
rainbow
trout
LC
50
3.9
mg
ae/
L
study
(
MRID
42532608)
estimate
a
slope
of
9.39(
95%
C.
I.
5.46­
13.33)
Based
on
this
slope,
and
taking
into
account
the
RQs
that
occur
for
aquatic
species
at
1.5
ae/
A
application
rate
for
MCPB
the
individual
mortality
associated
with
the
maximum
calculated
RQ
value
(.
01)
results
in
an
estimated
chance
of
individual
mortality
of
1
in
1.00E
+
16.
RQ s
exceedences
do
not
occur
for
freshwater
fish
species
at
MCPB
application
1.5
ae/
A.
The
corresponding
estimated
chance
of
individual
mortality
associated
with
the
listed
species
LOC
of
0.05
is
1
in
1.00E
+
16.

Freshwater
Invertebrates
Analysis
of
raw
data
from
the
daphnid
acute
LC
50
50.0study
(
MRID
42532602)
estimates
a
slope
of
9.22(
95%
C.
I.
5.41­
13.03).
Based
on
this
slope,
and
taking
into
account
the
RQs
that
occur
for
aquatic
species
for
MCPB
at
1.5ae/
A
application
rate
the
individual
mortality
associated
with
the
maximum
calculated
RQ
values
(.
01)
result
in
an
estimated
chance
of
individual
mortality
of
1
in
1.00E
+
16.
RQ s
exceedences
do
not
occur
for
freshwater
invertebrate
species
at
1.5
ae/
A
application
rate
.
The
corresponding
estimated
chance
of
individual
mortality
associated
with
the
listed
species
LOC
of
0.05
is
1
in
1.00E
+
16.

Estuarine
and
Marine
Fish
No
probit
dose
can
be
determined
due
to
lack
of
submitted
data.

Estuarine
and
Marine
Invertebrates
No
probit
dose
can
be
determined
due
to
lack
of
submitted
data.

Avian
Analysis
of
raw
data
from
the
bobwhite
quail
LD50
257
study
(
MRID
42560801)
estimates
a
slope
of
5.68
(
95%
C.
I.
3.12
­
8.25).
Based
on
this
slope,
and
taking
into
(
Phase
III
3/
07/
06)
    
55
  
147
account
the
RQs
that
occur
for
avian
terrestrial
species
at
MCPB
application
rate
of
1.5ae/
A,
the
individual
mortality
associated
with
the
maximum
calculated
RQ
value
(
2.26)
for
a
20
gram
bird
eating
short
grass
results
is
an
estimated
chance
of
individual
mortality
of
1
in
1.02E
+
00
.
RQ s
exceedances
do
not
occur
for
avian
species
at
all
food
type
scenarios.
The
corresponding
estimated
chance
of
individual
mortality
associated
with
the
listed
species
LOC
of
0.1
is
1
in
1.48E
+
08.

Mammals
Raw
data
is
not
provided
in
the
rat
acute
LD
50
832
ae
mg
/
kg­
bwt
study
(
MRID
116340)
to
calculate
a
slope.
The
default
slope
of
4.5
was
used
in
the
probit
analysis.
Based
on
this
slope,
and
taking
into
account
the
RQs
that
occur
for
mammal
terrestrial
species
at
MCPB
application
rate
1.5ae/
A
,
the
individual
mortality
associated
with
the
maximum
RQ
value
(
15
gram
mammal
and
35
gram
mammal),
respectively
eating
short
grass,
calculated
RQ
values
(.
17
and
.15)
result
in
an
estimated
chance
of
individual
mortality
of
1
in
3.74E
+
03
and
1
in
9.56E
+
03,
respectively.
RQ s
exceedences
do
not
occur
for
mammal
species
at
all
food
type
scenarios.
The
corresponding
estimated
chance
of
individual
mortality
associated
with
the
listed
species
LOC
of
0.1
is
1
in
4.17E
+
08
.

Data
Related
to
Under­
represented
Taxa:
Additional
effects
data
from
other
analyzed
sources
(
ECOTOX
Database)
requires
further
evaluation
for
data
related
to
under­
represented
taxa
and
support
study
data
for
MCPB.

Implications
of
Sublethal
Effects:
Chronic
studies
were
not
available
for
freshwater
and
estuarine
marine
aquatic
species
and
for
birds.
RQs
did
exceed
Chronic
LOCs
for
mammals
in
all
weight
classes
(
15
g,
35
g,
and
1000g)
for
consumption
of
short
grass,
tall
grass
and
broadleaf
forage/
small
insects
and
in
15
g
and
35g
mammals
for
consumption
of
fruit
and
large
insects.
Maternal
toxicity
observed
in
a
rat
developmental
toxicity
study
(
MRID
40865402)
included
decreased
body
weight
and
body
weight
gain
during
gestation
and
developmental
toxicity
observed
in
the
same
study
included
decreased
mean
body
weights/
litter,
increases
in
unossified
or
poorly
ossified
sites,
and
skeletal
variations.
Maternal
toxicity
observed
in
a
rabbit
developmental
toxicity
study
(
MRID
40865401)
included
death,
clinical
signs
of
toxicity,
decrease
in
body
weight
gain,
and
change
in
color
of
liver
and
kidneys.
It
should
be
noted
that
in
acute
bird
guideline
studies,
discolorations
on
several
organs,
including
white
areas/
film
on
the
heart,
liver,
gizzard,
gallbladder,
crop
and
intestines
were
also
observed.
In
addition,
sublethal
effects
in
subchronic
feeding
studies
(
13
weeks)
with
dogs
included
testicular
and
prostate
atrophy
and
curtailment
of
spermatogenic
activity
(
MRID
116345);
reduced
testes
weights
and
physiological
changes
in
clinical
chemistry
(
MRID
42883603).
The
reproductive
and
developmental
effects
observed
in
these
studies
may
lead
to
a
potential
concern
for
impacts
to
populations
of
mammals
consuming
feed
items
contaminated
with
MCPB
and
to
the
predators
that
feed
on
them.

Indirect
Effects
Analysis
(
Phase
III
3/
07/
06)
    
56
  
147
Acute
Risk
and
Acute
Restricted
Use
LOCs
were
exceeded
for
birds
(
20,
100,
and
1000
g)
consuming
the
various
feed
items
and
results
of
the
probit
dose
analysis
for
bobwhite
quail
indicated
a
1
in
15
chance
of
mortality
based
on
the
maximum
use
scenario
EEC.
Consequently,
there
may
be
a
concern
for
potential
indirect
effects
to
listed
species
dependent
upon
birds
that
consume
feed
items
(
short
and
tall
grasses;
broadleaf
plants;
small
and/
or
large
insects;
and
fruits,
seeds,
and
pods)
contaminated
with
MCPB
residues;
such
as
predatory
birds
and
mammals.

The
Acute
Risk
LOCs
for
non­
target
monocots
and
dicots
were
exceeded
for
plants
located
adjacent
to
treated
areas
and
in
semi­
aquatic
areas.
Exposure
to
MCPB
results
in
direct
effects
to
plant
species
that
could
result
in
indirect
effects
at
the
higher
levels
of
organization
(
i.
e.
population,
trophic
level,
community,
ecosystem).
The
guideline
terrestrial
plant
studies
indicate
direct
adverse
effects
to
seedling
emergence
as
well
as
non­
lethal
effects
including
brown
leaf
tips
in
cabbage,
corn,
onion,
ryegrass,
radish,
and
soybean;
necrosis
in
corn,
radish,
onion,
and
soybean;
chlorosis
in
onion,
cucumber,
and
lettuce;
stem
tumors
in
soybean
and
tomato;
leaf
curl
in
tomato,
and
decrease
in
size
in
cabbage,
cucumber,
lettuce,
onion,
and
ryegrass.
In
the
guideline
aquatic
vascular
plant
studies,
concentrations
as
low
as
0.16
mg
ae/
L
resulted
in
chlorosis,
curling,
and
decreased
root
formation
in
the
plant.
In
terrestrial
and
shallow­
water
aquatic
communities,
plants
are
the
primary
producers
upon
which
the
succeeding
trophic
levels
depend.

If
the
available
plant
material
is
impacted
due
to
the
effects
of
MCPB,
this
may
have
negative
effects
not
only
on
the
herbivorous
animals,
but
throughout
the
food
chain.
Also,
depending
on
the
severity
of
impacts
to
the
plant
communities
(
edge
and
riparian
vegetation),
community
assemblages
and
ecosystem
stability
may
be
altered
(
i.
e.
reduced
bird
populations
in
edge
habitats;
reduced
riparian
vegetation
resulting
in
increased
light
penetration
and
temperature
in
aquatic
habitats).
Furthermore,
reduction
of
upstream
riparian
vegetation
that
would
otherwise
supply
downstream
habitats
could
result
not
only
in
a
loss
of
a
significant
component
of
food
for
aquatic
herbivores
and
detritivores,
but
also
of
habitat
(
i.
e.
leaf
packs,
materials
for
case­
building
for
invertebrates).
The
assessment
of
risk
to
aquatic
receptors
both
freshwater
and
saltwater/
estuarine
systems
is
also
of
potential
concern.

Critical
Habitat
In
the
evaluation
of
pesticide
effects
on
designated
critical
habitat,
consideration
is
given
to
the
physical
and
biological
features
(
constituent
elements)
of
a
critical
habitat
identified
by
the
U.
S
Fish
and
Wildlife
and
National
Marine
Fisheries
Services
as
essential
to
the
conservation
of
a
listed
species
and
which
may
require
special
management
considerations
or
protection.
The
evaluation
of
impacts
for
a
screening
level
pesticide
risk
assessment
focuses
on
the
biological
features
that
are
constituent
elements
and
is
accomplished
using
the
screening­
level
taxonomic
analysis
(
risk
quotients,
RQs)
and
listed
species
levels
of
concern
(
LOCs)
that
are
used
to
evaluate
direct
and
indirect
effects
to
listed
organisms.
(
Phase
III
3/
07/
06)
    
57
  
147
The
screening­
level
risk
assessment
has
identified
potential
concerns
for
indirect
effects
on
listed
species
for
those
organisms
dependent
upon
birds,
small
mammals,
aquatic
vascular
plants,
and
terrestrial
and
semi­
aquatic
plants.
In
light
of
the
potential
for
indirect
effects,
the
next
step
for
EPA
and
the
Service(
s)
is
to
identify
which
listed
species
and
critical
habitat
are
potentially
implicated.
Analytically,
the
identification
of
such
species
and
critical
habitat
can
occur
in
either
of
two
ways.
First,
the
agencies
could
determine
whether
the
action
area
overlaps
critical
habitat
or
the
occupied
range
of
any
listed
species.
If
so,
EPA
would
examine
whether
the
pesticide's
potential
impacts
on
non­
endangered
species
would
affect
the
listed
species
indirectly
or
directly
affect
a
constituent
element
of
the
critical
habitat.
Alternatively,
the
agencies
could
determine
which
listed
species
depend
on
biological
resources,
or
have
constituent
elements
that
fall
into,
the
taxa
that
may
be
directly
or
indirectly
impacted
by
the
pesticide.
Then
EPA
would
determine
whether
use
of
the
pesticide
overlaps
the
critical
habitat
or
the
occupied
range
of
those
listed
species.
At
present,
the
information
reviewed
by
EPA
does
not
permit
use
of
either
analytical
approach
to
make
a
definitive
identification
of
species
that
are
potentially
impacted
indirectly
or
critical
habitats
that
is
potentially
impacted
directly
by
the
use
of
the
pesticide.
EPA
and
the
Service(
s)
are
working
together
to
conduct
the
necessary
analysis.

This
screening­
level
risk
assessment
for
critical
habitat
provides
a
listing
of
potential
biological
features
that,
if
they
are
constituent
elements
of
one
or
more
critical
habitats,
would
be
of
potential
concern.
These
correspond
to
the
taxa
identified
above
as
being
of
potential
concern
for
indirect
effects
and
include
the
following:
birds,
small
mammals,
aquatic
vascular
plants,
and
terrestrial
and
semi­
aquatic
plants.
This
list
should
serve
as
an
initial
step
in
problem
formulation
for
further
assessment
of
critical
habitat
impacts
outlined
above,
should
additional
work
be
necessary.

Co­
occurrence
Analysis
Because
the
Endangered
Species
LOCs
for
freshwater
vascular
plants
and
for
terrestrial
monocots
and
dicots
are
exceeded
for
the
use
of
MCPB,
the
LOCATES
was
run
for
all
taxonomic
groups.
Therefore,
a
potential
concern
exists
with
species
that
are
obligates
and
have
very
specific
habitats
or
feeding
requirements.
For
terrestrial
monocots
and
dicots,
both
the
Acute
Risk
LOCs
for
nonendangered
species
and
the
Endangered
Species
LOCs
were
exceeded;
consequently
a
potential
concern
arises
for
species
with
both
narrow
and
general
dependencies.
In
addition,
Endangered
Species
LOCs
were
exceeded
for
small
(
20g)
medium
(
100
g)
and
large
birds
(
1000
g)
feeding
on
short
grass,
tall
grass,
and
broadleaf
forage/
small
insects;
small
birds
feeding
on
fruit
and
large
insects;
small
(
15
and
35
g)
mammals
feeding
on
short
grass;
and
small
mammals
(
15
g)
feeding
on
broadleaf
forage/
small
insects.
Information
from
LOCATES,
as
presented
in
Table
IV.
i.
below,
indicates
that
several
potentially
affected
species
of
birds,
mammals
and
plants
appear
to
be
co­
located
with
pesticide
use
areas.
Results
of
the
probit
dose
analysis
for
bobwhite
quail
indicated
a
1
in
15
chance
of
mortality
based
on
the
maximum
use
scenario
EEC.
Consequently,
there
may
be
a
concern
for
potential
indirect
effects
to
listed
species
dependent
upon
birds
that
consume
feed
items
(
short
and
tall
grasses;
broadleaf
plants;
small
and/
or
large
(
Phase
III
3/
07/
06)
    
58
  
147
insects;
and
fruits,
seeds,
and
pods)
contaminated
with
MCPB
residues;
such
as
predatory
birds
and
mammals.
In
addition,
there
may
be
a
potential
concern
for
indirect
effects
related
to
plants
that
require
birds
and/
or
mammals
for
pollination
or
seed
dispersal
and
for
animals
that
use
burrows
for
shelter
or
breeding
habitat.
Results
of
this
risk
assessment
indicate
no
direct
risk
to
freshwater
fish
and
invertebrates;
however,
these
species
may
be
dependent
on
aquatic
plants
for
survival.

Table
IV
.
i.
Tabulation
by
taxonomic
group
and
crop
of
listed
species
that
occur
in
MCPB
use
areas
summarized
by
Locates
Taxonomic
Group
Bir
ds
Ma
mma
ls
Re
pti
les
A
mp
hib
ian
s
Fis
h
Cr
ust
ac
ea
ns
A
ra
c
h
ni
ds
Ins
ect
s
Sn
ail
s
Cl
am
s
Pla
nts
Peas
(
all
varieties)
48
38
21
10
39
11
1
27
10
37
35
0
Total
States
39
36
12
5
22
5
1
14
5
20
37
C.
Description
of
Assumptions,
Limitations,
Uncertainties,
Strengths
and
Data
Gaps
Uncertainties
and
assumptions
related
to
selection
of
parent
toxicity
data
and
expsoure
estimates
related
to
MCPB
the
degradate
MCPA.

The
risk
assessment
for
aquatic
organisms
estimated
exposure
concentrations
on
the
basis
of
residual
MCPB
plus
the
degradate
MCPA.
If
both
are
assumed
to
be
of
equal
toxic
potency,
no
bias
has
been
introduced
to
the
risk
assessment
by
this
assumption.
However,
A
comparison
of
MCPB
toxicity
data
with
the
available
toxicity
for
MCPA
published
in
the
EPA
RED
chapter
for
that
compound,
indicates
that
some
differences
in
(
Phase
III
3/
07/
06)
    
59
  
147
toxic
potency
may
exist
for
the
two
compounds.
Using
common
aquatic
species
tested
for
each
compound
(
acid
equivalent)
the
following
comparisons
can
be
made:

Species
Test
Type
MCPB
Result
MCPA
Result
Rainbow
trout
96­
h
LC50
3.9
mg
ae/
L
96
mg
ae/
L
Daphnid
48­
h
LC50
50
mg
ae/
L
82
mg
ae/
L
The
aquatic
organism
comparisons
would
suggest
that
MCPA
(
acid
equivalent)
is
less
toxic
that
the
MCPB.
Therefore,
assuming
equal
potency
between
the
two
compounds,
and
adding
the
exposures
together
would
likely
overestimate
risk
for
aquatic
organisms.
This
finding,
however,
does
not
alter
the
conclusions
of
the
aquatic
risk
assessment,
which
suggests
no
concern
for
acute
effects
in
freshwater
aquatic
organisms.
Chronic
data
for
risks
to
freshwater
fish,
freshwater
invertebrates,
estuarine
marine
fish
and
acute
estuarine
marine
fish
for
MCPB
were
calculated
via
acute
to
chronic
ratios
from
MCPA
data
due
to
lack
of
submitted
data
for
MCPB.

There
were
no
LOC
exceedences
for
chronic
risks
to
freshwater
fish,
freshwater
invertebrates,
estuarine
marine
fish
and
acute
estuarine
marine
fish
for
MCPB
based
on
values
calculated
from
MCPA
on
a
acute
to
chronic
ratio
for
both
Oregon
and
California
scenarios.

However,
there
is
low
confidence
in
these
numbers
due
to
interspecies
differences
and
toxicity
differences
between
MCPB
and
MCPA
for
freshwater
fish
and
invertebrates.
Higher
uncertainty
exists
with
estuarine
marine
acute
and
chronic
fish.
Estuarine
marine
invertebrates
were
calculated
with
acute
to
chronic
ratio
but
with
little
confidence.
LOCs
were
exceeded
for
acute
estuarine
marine
invertebrates
(
RQs
0.07
­
0.01)
for
acute
restricted
use
and
acute
endangered
species.

Therefore,
acute
estuarine
marine
fish
and
acute
estuarine
marine
invertebrates
for
MCPB
are
requested
because
no
estuarine
marine
studies
were
submitted
for
MCPB,
low
confidence
in
estuarine
marine
and
invertebrate
calculations
from
acute
to
chronic
ratios
and
the
apparent
differences
in
endpoints
for
MCPA
and
MCPB.
These
endpoint
differences
are
as
follows:
MCPA
is
less
toxic
to
acute
freshwater
fish
(
96
mg
ae/
L)
than
MCPB
(
3.9
mg
ae/
L)
However,
MCPB
is
more
toxic
to
acute
freshwater
invertebrates
(
50
mg
ae/
L)
than
MCPA
(
82
mg
ae/
L).
Therefore,
chronic
studies
for
freshwater
fish
and
invertebrates
will
be
requested
due
to
endpoint
differences
and
low
confidence
in
acute
to
chronic
ratios
as
mentioned
above.
The
chronic
studies
for
estuarine
marine
fish
and
estuarine
invertebrates
are
reserved
based
on
the
outcome
of
acute
estuarine
marine
fish
and
invertebrate
submitted
studies.
Input
values
and
calculations
on
the
acute
to
chronic
ratios
for
MCPA
and
MCPB
are
located
in
Appendix
J.

Terrestrial
wildlife
exposures
were
conducted
solely
on
the
exposure
for
MCPB.
MCPA
was
not
included
in
the
exposure
assessment.
A
comparison
of
MCPB
toxicity
data
with
the
available
toxicity
for
MCPA
published
in
the
EPA
RED
chapter
for
that
compound,
indicates
that
some
differences
in
toxic
potency
may
exist
for
the
two
compounds.
Using
common
terrestrial
species
tested
for
each
compound
(
acid
equivalent)
the
following
comparisons
can
be
made:

Species
Test
Type
MCPB
Result
MCPA
Result
Bobwhite
LD50
257
mg
ae/
kg­
bw
221­
377
mg
ae/
kg­
bw
(
Phase
III
3/
07/
06)
    
60
  
147
Rat
LD50
832
mg
ae/
kg­
bw
1383
mg
ae/
kg­
bw
The
comparison
for
bobwhite
quail
would
suggest
that
the
acute
potency
of
MCPB
lies
within
the
range
of
toxicity
for
acid
equivalent
MCPA.
Relying
solely
on
MCPB,
may
underestimate
the
contribution
of
MCPA
residues
to
overall
toxic
exposure.
However,
the
fact
that
the
exposure
model
incorporates
a
35­
day
halflife
assumption
tends
to
offset
this
potential
under
estimation.

EFED
is
aware
that
HED
is
considering
both
MCPB
and
MCPA
exposure
in
its
human
health
risk
assessment
and
treating
the
two
compounds
as
equally
toxic.
EFED,
as
per
the
approach
with
birds,
has
only
considered
the
MCPB
exposure.
However,
the
selection
of
the
long
35­
day
foliar
half­
life
would
suggest
that
any
contribution
of
MCPA
would
be
low.
Consequently,
EFED
does
not
believe
that
the
current
mammalian
wildlife
risk
assessment
has
any
extensive
bias
in
this
regard.

Uncertainties,
assumptions,
and
limitations
associated
with
models
Extrapolating
the
risk
conclusions
from
the
standard
pond
scenario
modeled
by
PRZM/
EXAMS
may
either
underestimate
or
overestimate
the
potential
risks.
Major
uncertainties
with
the
standard
runoff
scenario
are
associated
with
the
physical
construct
of
the
watershed
and
representation
of
vulnerable
aquatic
environments
for
different
geographic
regions.
The
physicochemical
properties
(
pH,
redox
conditions,
etc.)
of
the
standard
farm
pond
are
based
on
a
Georgia
farm
pond.
These
properties
are
likely
to
be
regionally
specific
because
of
local
hydrogeological
conditions.
Any
alteration
in
water
quality
parameters
may
impact
the
environmental
behavior
of
the
pesticide.
The
farm
pond
represents
a
well
mixed,
static
water
body.
Because
the
farm
pond
is
a
static
water
body
(
no
flow
through),
it
does
not
account
for
pesticide
removal
through
flow
through
or
accidental
water
releases.
However,
the
lack
of
water
flow
in
the
farm
pond
provides
an
environmental
condition
for
accumulation
of
persistent
pesticides.
The
assumption
of
uniform
mixing
does
not
account
for
stratification
due
to
thermoclines
(
e.
g.,
seasonal
stratification
in
deep
water
bodies).
Additionally,
the
physical
construct
of
the
standard
runoff
scenario
assumes
a
watershed:
pond
area
ratio
of
10.
This
ratio
is
recommended
to
maintain
a
sustainable
pond
in
the
Southeastern
United
States.
The
use
of
higher
watershed:
pond
ratios
(
as
recommended
for
sustainable
ponds
in
drier
regions
of
the
United
States)
may
lead
to
higher
pesticide
concentrations
when
compared
to
the
standard
watershed:
pond
ratio.

The
standard
pond
scenario
assumes
that
uniform
environmental
and
management
conditions
exist
over
the
standard
10
hectare
watershed.
Soils
can
vary
substantially
across
even
small
areas,
and
thus,
this
variation
is
not
reflected
in
the
model
simulations.
Additionally,
the
impact
of
unique
soil
characteristics
(
e.
g.,
fragipan)
and
soil
management
practices
(
e.
g.,
tile
drainage)
are
not
considered
in
the
standard
runoff
scenario.
The
assumption
of
uniform
site
and
management
conditions
is
not
expected
to
represent
some
site­
specific
conditions.
Extrapolating
the
risk
conclusions
from
the
standard
pond
scenario
to
other
aquatic
habitats
(
e.
g.,
marshes,
streams,
creeks,
and
shallow
rivers,
(
Phase
III
3/
07/
06)
    
61
  
147
intermittent
aquatic
areas)
may
either
underestimate
or
overestimate
the
potential
risks
in
those
habitats.

Uncertainties
and
data
gaps
associated
with
the
environmental
fate
and
toxicity
data
There
are
a
number
of
areas
of
uncertainty
in
the
terrestrial
and
the
aquatic
organism
risk
assessments
that
could
potentially
cause
an
underestimation
of
risk.
First,
this
assessment
accounts
only
for
exposure
of
non­
target
organisms
to
MCPB,
but
not
to
its
degradates.
The
risks
presented
in
this
assessment
could
be
underestimated
if
degradates
also
exhibit
toxicity
under
the
conditions
of
use
proposed
on
the
label.
Data
are
not
available
concerning
the
fate
and
toxicity
of
the
photolytic
degradation
products
of
MCPB.
MCPA
is
a
degradation
product
of
biodegradation
in
soil
and
this
assessment
provides
available
toxicity
data
for
MCPA
that
indicates
that
the
toxicity
of
MCPA
acid
is
very
similar
to
that
of
MCPB
(
Reregistration
Eligibility
Decision
for
MCPA,
2004).
Second,
the
risk
assessment
only
considers
the
most
sensitive
species
tested
and
only
considers
a
subset
of
possible
use
scenarios.
For
the
aquatic
organism
risk
assessment,
there
are
uncertainties
associated
with
the
PRZM/
EXAMS
model,
input
values,
and
scenarios
including
the
use
of
surrogate
scenarios,
however
these
uncertainties
cannot
be
quantified.
The
potential
impacts
of
these
uncertainties
are
outlined
in
the
Aquatic
Exposure
and
Risk
Assessment
and
the
Terrestrial
Exposure
and
Risk
Assessment
sections
of
this
document.

Additional
uncertainty
results
from
the
lack
of
information
and/
or
data
in
several
components
of
this
ecological
risk
assessment.
First,
MCPB
chronic
toxicity
data
for
birds
and
aquatic
organisms
are
not
available,
thus
the
potential
risk
due
to
prolonged
exposures
cannot
be
estimated.
Second,
data
are
unavailable
concerning
residue
levels
in
foliage,
flowers,
and
seeds
to
accurately
predict
potential
risks
to
terrestrial
organisms
which
may
contact
MCPB
residues
after
application.
Third,
estuarine/
marine
fish
and
invertebrate
data
are
not
available.
Finally,
aerobic
and
anaerobic
aquatic
metabolism
and
terrestrial
field
dissipation
studies
have
not
been
submitted
for
MCPB.
APPENDIX
A:
Environmental
Fate
Studies
and
Selected
Chemical
Structures
(
Phase
III
3/
07/
06)
    
63
  
147
MCPB
(
acid)

MCPB
(
sodium
salt)

MCPA
(
Phase
III
3/
07/
06)
    
64
  
147
CHPA
(
transient
intermediate)

CHPA­
hexose
conjugate
(
Phase
III
3/
07/
06)
    
65
  
147
Environmental
Fate
Studies
Hydrolysis
Das,
Y.
T.
1992.
Hydrolysis
of
[
14C]
MCPB
in
aqueous
solutions
buffered
at
pH
5,
7
and
9.
Unpublished
study
performed
by
Innovative
Scientific
Services,
Inc.,
Piscataway,
NJ
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Lyon
Cedex,
France.
ISSI
Study
Number
92010;
Rhone­
Poulenc
Study
Number
92­
06.
Study
was
initiated
on
February
17,
1992
and
completed
on
September
23,
1992.
MRID
42574301
The
hydrolysis
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
(
MCPB),
at
10.3
mg
a.
i/
L,
was
studied
in
the
dark
at
25
±
1
°
C
in
sterile
aqueous
0.1
M
buffer
solutions
adjusted
to
pH
5
(
acetate),
pH
7
(
phosphate)
and
pH
9
(
borate)
for
30
days.
The
experiment
was
conducted
in
accordance
with
the
US
EPA
Pesticide
Assessment
Guidelines,
Subdivision
N,
Section
161­
1
and
in
compliance
with
40
CFR
160
(
FIFRA
Good
Laboratory
Practice
Standards).
Samples
were
analyzed
for
MCPB
and
its
transformation
products
without
extraction
or
concentration
using
HPLC.
Identification
was
made
by
comparison
to
unlabeled
reference
standards
and
confirmed
by
GC­
MS.

Total
radiocarbon
recovery
in
the
pH
5
solution
averaged
(
n
=
14)
99.8
±
0.6%
of
the
applied,
in
the
pH
7
solution
averaged
101.0
±
0.4%,
and
in
the
pH
9
solution
averaged
102.1
±
0.4%.
The
concentration
of
[
14C]
MCPB
decreased
from
94.4%
at
day
0
to
91.5%
of
the
applied
at
study
termination
in
the
pH
5
solution,
from
95.8%
to
91.9%
at
pH
7,
and
from
95.7%
to
93.2%
of
the
applied
at
pH
9.
No
major
transformation
product
was
detected
in
any
of
the
pH
solutions.
Five
[
14C]
compounds
were
isolated
at
maximum
concentrations
of
1.6­
5.2%
of
the
recovered;
one
was
tentatively
identified
as
4­(
otolyloxy
butyric
acid.
Volatiles
were
not
measured.
Half­
life
values
were
not
calculated.
Since
<
5%
of
the
applied
MCPB
degraded
during
the
30
days,
the
slope
of
the
regression
line
was
not
significantly
different
from
zero
(
a
grossly
extrapolated
half­
life
would
be
approximately
500
days).

Photolysis
Das,
Y.
T.
1992.
Photodegradation
of
[
14C]
MCPB
in
aqueous
solutions
buffered
at
pH
5,
7
and
9
under
artificial
sunlight.
Unpublished
study
performed
by
Innovative
Scientific
Services,
Inc.,
Piscataway,
NJ
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Lyon
Cedex,
France.
ISSI
Study
Number
92011;
Rhone­
Poulenc
Study
Number
92­
07.
Study
was
initiated
on
February
17,
1992,
and
completed
on
September
23,
1992.
MRID
42574302
The
aqueous
phototransformation
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)

butyric
acid
(
MCPB)
was
studied
at
25
±
1
°
C
in
sterile
aqueous
acetate,
phosphate
and
borate
buffer
solutions
at
pH
5,
7
and
9,
respectively
at
an
initial
concentration
of
10.3
mg
a.
i/
L
under
irradiation
using
a
filtered
xenon
arc
lamp
for
30
days
(
12
hours
light/
12
hours
dark).
Test
vessels
were
not
connected
to
traps
for
the
collection
of
CO
2
and
organic
volatiles
in
the
definitive
study.
Irradiated
and
dark
control
samples
were
sampled
at
0,
1,
2,
3,
4,
7,
14
and
30
days;
and
0,
1,
3,
7,
14,
21
and
30
days,
respectively.
Samples
were
analyzed
for
MCPB
and
its
transformation
products
without
extraction
or
concentration
using
HPLC.
(
Phase
III
3/
07/
06)
    
66
  
147
Identification
was
made
by
comparison
to
unlabeled
reference
standards
and
confirmed
by
GC­
MS.
In
the
irradiated
samples,
total
radiocarbon
recovery
total
radiocarbon
recovery
in
the
pH
5
solution
averaged
(
n
=
14)
96.9
±
1.6%,
in
the
pH
7
solution
averaged
98.3
±
1.5%,
and
in
the
pH
9
solution
averaged
99.3
±
1.6%
of
the
applied
amount
at
pH
5,
7
and
9,
respectively.
The
reviewer­
calculated
concentrations
of
[
14C]
MCPB
decreased
from
94.4%
at
day
0
to
0.2%
of
the
applied
at
day
30
in
the
pH
5
solution,
from
95.9%
to
<
0.1%
at
pH
7,
and
from
95.7%
to
<
0.1%
at
pH
9.
Five
transformation
products
were
isolated
at
>
10%
of
the
applied:
4
­(
4­
hydroxy­
otolyloxy
butyric
acid;
2,4­
dihyroxyphenyl
formate;
o­
cresol;
benzoic
acid;
and
2­
hydroxyphenyl
formate.
4­(
4­
Hydroxy­
o­
tolyloxy)
butyric
acid
was
a
mean
maximum
of
32.0%
of
the
applied
at
4
days
and
decreased
to
4.8%
by
30
days
in
the
pH
5
solution;
was
27.5%
at
7
days
and
decreased
to
5.1%
in
the
pH
7
solution;
and
was
17.4%
at
30
days
in
pH
9
solution.
2,4­
Dihyroxyphenyl
formate
was
a
maximum
mean
concentration
of
39.5%
of
the
applied
at
30
days
in
the
pH
5
solution;
was
33.0­
35.3%
at
14­
30
days
in
the
pH
7
solution;
and
was
22.8%
at
30
days
in
the
pH
9
solution.
o­
Cresol
was
a
maximum
mean
concentration
of
17.1%,
47.3%
and
25.7%
of
the
applied
at
30
days
in
pH
5,
7
and
9
solutions,
respectively.
Benzoic
acid
was
at
a
maximum
mean
concentration
of
13.1%
at
30
days
inthe
pH
5
solution,
1.6%
at
7
days
in
the
pH
7
solution,
and
7.2%
at
30
days
in
the
pH
9
solution.
2­
Hydroxyphenyl
formate
was
a
maximum
mean
concentration
of
10.0%,
4.7%
and
14.0%
of
the
applied
at
14
days
in
pH
5,
7
and
9
solutions,
respectively,
and
decreased
in
all
solutions
by
30
days.
There
were
two
minor
transformation
products:
4­(
o­
tolyloxy)
butyric
acid
at
a
maximum
mean
1.5­
2.5%
of
the
applied
and
4­
chloro­
ocresol
(
pH
5
and
9
only)
at
a
maximum
3.6­
5.1%.
Volatiles
were
not
measured.
Eight
unidentified
[
14C]
compounds,
each
a
maximum
of
 
8.8%
of
the
applied,
totaled
<
14.3%
at
all
sampling
intervals.
Volatiles
were
not
measured.

In
the
nonirradiated
samples,
total
radiocarbon
recovery
in
the
pH
5
solution
averaged
(
n
=
14)
99.8
±
0.6%
of
the
applied,
in
the
pH
7
solution
averaged
101.0
±
0.4%,
and
in
the
pH
9
solution
averaged
102.1
±
0.4%.
The
reviewer­
calculated
concentrations
of
[
14C]
MCPB
decreased
from
94.4%
at
day
0
to
91.5%
of
the
applied
at
day
30
in
the
pH
5
solution,
from
95.8%
to
91.9%
at
pH
7,
and
from
95.7%
to
93.2%
of
the
applied
at
pH
9.
No
major
transformation
product
was
detected
in
any
of
the
pH
solutions.
Fifteen
[
14C]
compounds
were
isolated,
of
which
five
were
detected
at
maximum
concentrations
of
1.6­
5.2%
of
the
recovered.
Volatiles
were
not
measured.

The
half­
lives
of
MCPB
in
the
irradiated
pH
5,
7
and
9
buffer
solutions
were
calculated
assuming
pseudo
first­
order
reaction
kinetics.
Respective
values
were
determined
to
be
2.2,
2.6
and
2.4
days,
respectively.
There
was
no
statistically
significant
difference
between
the
rate
of
degradation
at
different
pHs.
Since
there
was
no
degradation
in
the
dark
control,
the
phototransformation
halflives
do
not
need
to
be
adjusted
for
degradation
in
the
controls.
Likewise,
since
the
wavelengths
and
intensity
of
the
light
source
were
equivalent
to
sunlight,
no
adjustments
for
light
source
are
necessary.

Transformation
Products:
In
the
irradiated
samples,
five
transformation
products
were
isolated
at
>
10%
of
the
applied:
4
­(
4­
hydroxy­
o­
tolyloxy)
butyric
acid;
2,4­
dihyroxyphenyl
formate;
o­
cresol;
benzoic
acid;
and
2­
hydroxyphenyl
formate.
4­(
4­
Hydroxy­
o­
tolyloxy)
butyric
acid
was
a
mean
maximum
of
32.0%
of
the
applied
at
4
days
and
decreased
to
4.8%
by
30
days
in
the
pH
5
solution;
was
27.5%
at
7
days
and
decreased
to
5.1%
in
the
pH
7
solution;
and
was
17.4%
at
30
days
in
pH
9
solution.
2,4­
Dihyroxyphenyl
formate
was
a
maximum
mean
concentration
of
39.5%
of
the
applied
at
30
days
in
the
pH
5
solution;
was
33.0­
35.3%
at
14­
30
days
in
the
pH
7
solution;
(
Phase
III
3/
07/
06)
    
67
  
147
and
was
22.8%
at
30
days
in
the
pH
9
solution.
o­
Cresol
was
a
maximum
mean
concentration
of
17.1%,
47.3%
and
25.7%
of
the
applied
at
30
days
in
pH
5,
7
and
9
solutions,
respectively.
Benzoic
acid
was
at
a
maximum
mean
concentration
of
13.1%
at
30
days
in
the
pH
5
solution,
1.6%
at
7
days
in
the
pH
7
solution,
and
7.2%
at
30
days
in
the
pH
9
solution.
2­
Hydroxyphenyl
formate
was
a
maximum
mean
concentration
of
10.0%,
4.7%
and
14.0%
of
the
applied
at
14
days
in
pH
5,
7
and
9
solutions,
respectively,
and
decreased
in
all
solutions
by
30
days.
There
were
two
minor
transformation
products:
4­(
o­
tolyloxy)
butyric
acid
at
a
maximum
mean
1.5­
2.5%
of
the
applied
and
4­
chloro­
o­
cresol
(
pH
5
and
9
only)
at
a
maximum
3.6­
5.1%.
Volatiles
were
not
measured.
Eight
unidentified
[
14C]
compounds,
each
a
maximum
of
 
8.8%
of
the
applied,
totaled
<
14.3%
at
all
sampling
intervals.
Volatiles
were
not
measured.

In
the
non­
irradiated
samples,
no
major
transformation
product
was
detected
in
any
of
the
pH
solutions.
Fifteen
[
14C]
compounds
were
isolated,
of
which
five
were
detected
at
maximum
concentrations
of
1.6­
5.2%
of
the
recovered.
Volatiles
were
not
measured.

Pathway:
It
was
proposed
that
at
all
pHs,
MCPB
was
dechlorinated
then
hydroxylated,
resulting
in
the
formation
of
4­(
4­
hydroxy­
o­
tolyloxy)
butyric
acid
(
p.
33,
Figure
80,
p.
138,
MRID
42574302).

Aqueous
Photolysis
Summary
Half­
lives
for
irradiated
samples:
2.2
days
(
pH
5),
2.6
days
(
pH
7)
and
2.4
days
(
pH
9)

Major
identified
transformation
products:
4­(
4­
hydroxy­
o­
tolyloxy)
butyric
acid,
2,4­
dihyroxyphenyl
formate,
o­
cresol,
benzoic
acid
and
2­
hydroxyphenyl
formate.

Minor
identified
transformation
products:
4­(
o­
tolyloxy)
butyric
acid
and
4­
chloro­
o­
cresol.

Adsorption/
Desorption
in
Soil
Robson,
M.
M.
1993.
Determination
of
adsorption/
desorption
characteristics
of
4­(
2­
methyl,
4­
chlorophenoxy)
butyric
acid
(
MCPB)
in
soil.
Unpublished
study
performed
by
Hazleton
UK,
North
Yorkshire,
England.
HUK
Study
No.
68/
127.
Study
sponsored
by
Rhône­
Poulenc
Agriculture,
Essex,
England.
Study
initiated
April
3,
1992
and
completed
February
10,
1993.
MRID
42693701
The
adsorption/
desorption
characteristics
of
phenyl
ring­
labeled
[
14C]
MCPB
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
dissolved
in
methanol
was
studied
in
sterile
sandy
clay
loam
soil
[
pH­
6.09,
organic
carbon
­
1.3%]
from
France,
and
the
following
three
soils
and
one
sediment
from
England:
sand
soil
[
pH
­
7.93,
organic
carbon
­
0.53%],
sandy
loam
soil
[
pH
­
6.08,
organic
carbon
­
0.76%],
clay
loam
soil
[
pH
­
7.6,
organic
carbon
­
2.49%],
and
sandy
loam
aquatic
sediment
[
pH
­
5.95,
organic
carbon
­
2.85%]
in
a
batch
equilibrium
experiment.
The
soils
and
sediment
were
sterilized
using
gamma
irradiation
(
25
kGy).
The
adsorption
phase
of
the
study
was
carried
out
by
equilibrating
sterilized
soil
with
[
14C]
MCPB
at
nominal
concentrations
of
0.04,
0.2,
1.0,
and
5.0
µ
g/
mL
at
ambient
temperature
(
19­
23
°
C)
for
48
hours;
lighting
conditions
were
not
reported.
The
equilibrating
solution
used
was
0.01
M
CaCl2,
with
soil/
solution
ratios
of
1:
5
(
w:
v)
for
the
four
soils
and
one
sediment.
The
desorption
phase
of
the
study
was
carried
out
by
replacing
the
adsorption
solution
with
an
equivalent
volume
of
sterilized,
pesticide
(
Phase
III
3/
07/
06)
    
68
  
147
free
0.01
M
CaCl2
solution
and
equilibrating
once
for
48
hours
at
19­
23
°
C.
The
desorption
phase
was
conducted
once.

After
48
hours
of
equilibration,
0.33­
13.99,
0.05­
11.20,
0.09­
11.99,
0.13­
11.11,
and
0.69­
76.33
µ
g/
g
of
the
applied
[
14C]
MCPB
was
adsorbed
to
the
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam
soils
and
sediment,
respectively.
The
mean
adsorption
Kads
values
were
1.69,
0.26,
0.65,
0.78,
and
10.58
mL/
g
for
the
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam
soils
and
sandy
loam
sediment,
respectively.
Adsorption
Koc
values
were
129.57,
47.91,
85.54,
31.27,
and
371.17
mL/
g
for
the
sandy
clay
loam,
sand,
sandy
loam,
and
clay
loam
soils
and
sandy
loam
sediment,
respectively.
At
the
end
of
the
desorption,
64.0%,
32.18%,
60.22%,
60.59%,
and
24.63%
of
the
adsorbed
amount
was
desorbed
in
the
sandy
clay
loam,
sandy,
sandy
loam,
and
clay
loam
soils
and
sandy
loam
sediment,
respectively.
The
desorption
Koc
and
Kd
values
were
not
provided.

Anaerobic
Biotransformation
in
Soil
Goodyear,
A.
1993.
(
14C)­
MCPB:
anaerobic
soil
metabolism.
Unpublished
study
performed
by
Hazleton
UK,
North
Yorkshire,
England,
and
sponsored
by
MCPB
Task
Force,
c/
o
Rhône­
Poulenc
Agricultural
Limited,
Essex,
England.
Laboratory
Study
No.
68/
131
and
Report
No.
68/
131­
1015.
MRID
43015501
The
biotransformation
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
(
MCPB)
was
studied
in
sandy
loam
soil
(
pH
in
water
7.7,
organic
carbon
0.3%)
incubated
for
62
days
under
anaerobic
conditions
(
flooding
plus
nitrogen
atmosphere)
in
darkness
at
25
±
1
°
C
following
4
days
of
aerobic
incubation.
[
14C]
MCPB
was
applied
at
a
nominal
rate
of
3.4
mg
a.
i./
kg
soil
(
equivalent
to
3.8
kg
a.
i./
ha).
Soil
samples
were
analysed
after
0
and
4
days
of
aerobic
incubation
and
after
8,
14,
29
and
62
days
of
anaerobic
incubation
(
12,
18,
33
and
66
days
posttreatment).

Overall
material
balance
averaged
99.6
±
5.9%
(
range
91.1­
110.3%,
n
=
2)
of
the
applied
radioactivity,
with
material
balances
declining
from
109.6
±
0.7%
at
day
0
to
91.7
±
0.6%
(
91.1­
92.3%)
after
29
days
of
anaerobic
incubation
(
33
days
posttreatment),
then
increasing
to
96.2
±
0.5%
after
62
days
(
66
days
posttreatment,
final
sampling
interval).
Distribution
ratios
for
[
14C]
residues
between
the
soil
and
water
layer
were
5:
1
after
8
days
of
anaerobic
incubation,
10:
1
after
29
days
and
7:
1
after
62
days
(
Attachment
2).

In
the
sandy
loam
soil:
water
systems,
[
14C]
MCPB
decreased
from
an
average
40.9
±
2.6%
of
the
applied
at
4
days
posttreatment
just
prior
to
flooding
to
17.7
±
1.8%
after
14
days
of
anaerobic
incubation
(
18
days
posttreatment)
and
7.8
±
0.1%
after
29
days
(
33
days
posttreatment),
then
increased
to
22.5
±
4.9%
after
62
days
(
66
days
posttreatment).
[
14C]
MCPB
in
the
soil
decreased
from
106.3
±
0.0%
of
the
applied
at
day
0
to
40.9
±
2.6%
at
4
days
just
prior
to
flooding,
17.0
±
2.3%
after
8
days
of
anaerobic
incubation,
3.0
±
0.7%
after
29
days,
then
increased
to
14.2
±
1.5%
after
62
days.
[
14C]
MCPB
in
the
water
decreased
from
11.9
±
5.0%
of
the
applied
after
8
days
of
anaerobic
incubation
(
12
days
post.)
to
4.7
±
0.7%
after
29
days,
then
increased
to
8.3
±
3.4%
after
62
days.

The
major
transformation
product
of
[
14C]
MCPB
was
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA)
detected
at
maximums
of
34.8%
in
the
soil
at
4
days
just
prior
to
flooding,
33.4%
in
the
water
after
14
days
of
anaerobic
incubation,
and
46.9%
in
the
total
soil:
water
system
after
29
days.
(
Phase
III
3/
07/
06)
    
69
  
147
After
62
days
of
anaerobic
incubation,
[
14C]
MCPA
was
6.6
±
2.1%
of
the
applied
in
the
soil,
27.8
±
4.8%
in
the
water
and
34.3
±
2.7%
in
the
entire
soil:
water
system.

Half­
life:
Half­
life
values
of
[
phenyl­
U­
14C]
MCPB
in
the
total
soil:
water
system
were
determined
by
the
registrant
using
linear
regression
analysis
and
the
Timme­
Freshe
square­
root
of
first
order
decay
model
of
the
mean
[
14C]
MCPB
recovered
at
the
8­,
14­
and
33­
day
anaerobic
intervals
(
12­
to
33­
day
posttreatment
intervals;
pp.
25,
28,
31,
see
Reviewer's
Comment
no.
1).
Half­
life
values
of
[
14C]
MCPB
in
the
water,
soil
and
entire
system
were
determined
by
the
Dynamac
reviewer
using
least
squares
linear
regression
analysis,
based
on
first­
order
kinetics,
of
[
14C]
MCPB
recovered
in
each
sample
as
calculated
by
Corel
Quattro
Pro
8
software
(
Attachment
2).

Table
7:
Half­
life
(
t1/
2)
values
of
MCPB
in
sandy
loam
soil
under
62
days
of
anaerobic
conditions
following
4
days
of
aerobic
incubation.

half­
life
(
days)

Regression
Equation
System
Intervals
used
(
days
posttreatment)
t1/
2
r2
water
12­
33
18.9
0.520
soil
4­
33
7.8
0.975
entire
system
4­
33
11.9
0.946
First
Order
­
linear
least
squares
regression.
Linear
form
y
=
mx
+
b
as
lnC=
­
kt
+
lnC0;
lnC0
is
initial
concentration
(
b
=
y
intercept),
lnC
is
concentration
at
time
t
(
y),
k
is
the
slope
(
m),
t
is
time
(
x)
or
kt
=
lnC0
­
lnC.
Half­
life
(
t
½
)
=
­(
ln
2/
k).
entire
system
12­
33
11.4
0.996
Timme­
Freshe
­
computer
model
fits
data
to
1st,
1.5
and
2nd
order
decay
curves;
a
square­
root
of
the
1st
order
decline
curve
was
utilized.
entire
system
12­
33
9.5
not
reported
Transformation
Products:
The
major
transformation
product
of
[
14C]
MCPB
was
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA)
detected
at
maximums
of
34.8%
in
the
soil
at
4
days
just
prior
to
flooding,
33.4%
in
the
water
after
14
days
of
anaerobic
incubation,
and
46.9%
in
the
total
soil:
water
system
after
29
days
(
pp.
41­
43).
After
62
days
of
anaerobic
incubation,
[
14C]
MCPA
was
6.6
±
2.1%
(
4.5­
8.6%)
of
the
applied
in
the
soil,
27.8
±
4.8%
(
23.0­
32.6%)
in
the
water,
and
34.3
±
2.7%
(
31.6­
37.0%)
in
the
entire
system.

Aerobic
Soil
Biotransformation
John,
A.,
et
al.
1994.
MCPB:
aerobic
soil
metabolism.
Unpublished
study
performed
and
sponsored
by
MCPB
Task
Force,
c/
o
Rhône­
Poulenc
Agricultural
Limited,
Essex,
England.
Laboratory
Project
and
Study
ID:
P
93/
194.
MRID
43247601
The
biotransformation
of
[
phenyl­
U­
14C]­
labeled
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid
(
MCPB)
was
studied
in
sandy
loam
soil
(
pH
in
water
5.38,
organic
carbon
2.3%)
from
the
United
Kingdom
for
120
days
under
aerobic
conditions
in
darkness
at
22
±
1
°
C
and
soil
moisture
of
75%
of
1/
3
bar.
[
14C]
MCPB
was
applied
at
a
nominal
rate
of
3.4
mg
a.
i./
kg
soil
(
equivalent
to
3.8
kg
a.
i./
ha).
The
test
system
consisted
of
flasks
(
not
described)
containing
treated
soil
attached
in
(
Phase
III
3/
07/
06)
    
70
  
147
series
to
a
flow­
through
apparatus
with
traps
for
the
collection
of
CO2
and
volatile
organics.
Soil
samples
were
analysed
after
0,
1,
3,
8,
15,
21,
29,
65,
90
and
120
days
of
incubation.

The
major
transformation
product
of
[
14C]
MCPB
was
volatilized
14CO2
which
increased
to
a
maximum
64.9
±
0.6%
of
the
applied
at
65
days
and
was
54.5­
61.8%
at
90­
120
days;
no
organic
volatiles
were
detected.
Two
minor
transformation
products
identified
in
soil
extracts
were
the
hexose
conjugate
of
(
4­
chloro­
2­
methylphenoxy)­
2­
 ­
glucopyranoside
acetic
acid
minor
(
CHPA)
and
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA),
which
were
each
detected
at
maximums
of
9.5%
(
8
days)
and
7.2%
(
15
days)
of
the
applied
radioactivity,
respectively,
with
both
decreasing
to
 
2.1%
by
120
days.
Five
unidentified
[
14C]
compounds
(
Metabolites
3­
7)
were
each
 
5.3%
of
the
applied
at
any
sampling
interval.
Extractable
[
14C]
residues
decreased
from
99.7
±
1.9%
of
the
applied
at
day
0
to
4.9­
5.8%
at
65­
120
days.
Non­
extractable
residues
increased
from
1.0%
at
day
0
to
41.5
±
1.3%
at
29
days,
then
gradually
decreased
to
30.9
±
0.2%
at
120
days.
In
8­
and
120­
day
extracted
soil,
6.2­
9.5%,
9.9­
13.8%,
and
7.7­
10%
of
the
applied
was
associated
with
the
fulvic
acid,
humic
acid,
and
humin
fractions,
respectively.

Soil
type:
United
Kingdom
(
Essex)
sandy
loam.
First­
order
half­
life
for
parent
MCPB*:
18
days
(
data
from
0­
120
days)
Combined
first­
order
half­
life
for
MCPB,
MCPA,
and
CHPA­
hexose
conjugate:
26
days
(
data
from
0­
120
days)

*
Note:
There
was
an
error
in
the
calculation
of
half­
life
of
MCPB
in
the
original
Data
Evaluation
Report
(
DER).
In
the
original
DER
the
half­
life
for
the
120­
day
period
was
incorrectly
calculated
to
be
approximately
27
days.

Major
transformation
product:
CO2.

Minor
transformation
products:
(
4­
Chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA)
(
4­
chloro­
2­
methylphenoxy)­
2­
 ­
glucopyranoside
acetic
acid
(
CHPA,
as
hexose
conjugate)
Five
unidentified
[
14C]
compounds.

A
biotransformation
pathway
for
the
degradation
of
MCPB
in
aerobic
soil
was
proposed
by
the
registrant
(
p.
42).
The
putative
path
was
MCPB
degradation
to
(
4­
chloro­
2­
methylphenoxy)
acetic
acid
(
MCPA),
which
degrades
to
(
4­
chloro­
2­
methylphenoxy)­
2­
 ­
glucopyranoside
acetic
acid
minor
(
CHPA)
and
conjugates
with
hexose.
There
was
significant
production
of
CO2
and
soil
bound
residues.

Soil
Leaching
John,
A.
E.,
M.
K.
Jones
and
P.
Lowden.
1994.
MCPB:
Fresh
and
aged
leaching
study
in
five
soils.
Laboratory
Project
ID.
P
92/
333.
Unpublished
study
performed
and
submitted
by
Rhône­
Poulenc
Agriculture
Limited,
Essex,
England.
Laboratory
Project
ID:
P
92/
333.
MRID
43466401
(
Phase
III
3/
07/
06)
    
71
  
147
This
column
leaching
study
was
previously
considered
supplemental
because
the
CEC
of
the
test
soils
and
sediment
was
not
reported,
and,
for
the
aging
portion
of
the
study,
degradates
were
not
identified
after
aging
and
prior
to
leaching.
In
the
course
of
the
current
fate
assessment,
we
again
evaluated
the
results
of
this
study
for
possible
utility
in
characterization
of
mobility.
We
noted
that
missing
from
the
report
was
the
concentration
of
MCPB,
if
any,
in
any
of
the
leachates.
Therefore,
although
ostensible
Kd
values
were
reported
in
the
study,
it
is
unclear
what
these
values
and
their
method
of
computation
represent
or
whether
these
reasonably
approximate
equilibrium
values.
Therefore,
the
reported
Kd
values
are
presently
of
indeterminate
value.
However,
since
the
Agency
does
not
rely
on
column
leaching
studies
for
quantitative
exposure
assessments,
and
since
we
do
have
an
acceptable
batch
equilibrium
study
(
see
adsorption­
desorption
study
above,
MRID
42693701),
which
is
the
preferred
method
for
quantitative
modeling
purposes,
results
from
the
column
leaching
study
are
not
needed
for
MCPB.
Therefore,
if
the
registrant
so
chooses,
no
further
work
is
required
for
this
study.
APPENDIX
B:
Aquatic
Exposure
Model
Results
(
Phase
III
3/
07/
06)
    
73
  
147
Aquatic
Exposure
Modeling
PRZM
3.12
and
EXAMS
2.98
models
in
tandem
Aquatic
exposure
concentrations
for
MCPB
in
the
standard
field
pond
were
estimated
using
the
PRZM
3.12
and
EXAMS
2.98
models
in
tandem.
PRZM/
EXAMS
is
a
Tier
II
screening
model
designed
to
estimate
pesticide
concentrations
found
in
water
at
the
edge
of
a
treated
field.
As
such,
it
provides
high­
end
values
of
the
pesticide
concentrations
that
might
be
found
in
ecologically
sensitive
environments
following
pesticide
application.

PRZM/
EXAMS
is
a
multi­
year
runoff
model
that
also
accounts
for
spray
drift
from
single
and
multiple
applications.
In
the
ecological
exposure
assessment,
PRZM/
EXAMS
simulates
a
10
hectare
(
ha)
field
immediately
adjacent
to
a
1
ha
pond,
2
meters
deep
with
no
outlet.
The
geographic
location
of
the
field
is
specific
to
the
crop
being
simulated
using
site
specific
information
on
the
soils,
weather,
cropping,
and
management
factors
associated
with
the
scenario.
The
crop/
location
scenario
is
intended
to
represent
a
high­
end
vulnerable
site
on
which
the
crop
is
normally
grown.
Based
on
historical
rainfall
patterns,
the
pond
receives
multiple
runoff
events
during
the
years
simulated.

Acute
risk
assessments
are
performed
using
1
in
10
year
peak
EEC
values
for
single
applications
of
MCPB.
Chronic
risk
assessments
for
aquatic
invertebrates
and
fish
are
performed
using
the
average
21­
day
and
60­
day
EECs,
respectively.

Table
B.
1.
presents
the
input
parameters
used
in
the
Tier
II
PRZM/
EXAMS
modeling
for
ecological
assessment
of
MCPB
for
surface
water
sources.
To
simulate
field
application
of
MCPB
to
peas,
two
scenarios
were
selected
representing
different
MCPB
usage
areas
based
on
geography
and
weather.
A
California
lettuce
and
an
Oregon
snap
bean
scenario
were
chosen
as
representative
of
the
agricultural
practices
and
areas
in
which
peas
are
grown.
The
EECs
for
the
two
scenarios
are
presented
in
Table
B.
2.
The
Oregon
scenario
represents
the
typical
use
of
MCPB
application
to
peas,
and
the
California
scenario
represents
a
reasonable
upper
bound
estimate.
Results
for
the
two
cases
are
similar.
We
also
investigated
several
other
possible
scenarios
(
approximately
six
others),
and
found
all
EECs
to
be
rather
tightly
grouped
in
a
range
from
approximately
15
to
40
µ
g
ae/
L.
The
PRZM/
EXAMS
input
and
output
files
from
the
California
and
Oregon
aquatic
ecological
exposure
assessments
for
aerial
and
ground
applications
are
presented
in
Tables
B.
3.,
B.
4.,
B.
5.
and
B.
6.

TABLE
B.
1.
PRZM/
EXAMS
Input
Parameters
for
MCPB.

Model
Parameter
Value
Comments
Source
Application
Rate
per
Event
1.68
kg
ae/
acre
(
1.5
lbs
ae/
acre)
application
to
peas
by
ground
and
aerial
spray
application
Label
Number
of
Applications
per
Crop
1
application
per
(
Phase
III
3/
07/
06)
    
74
  
147
TABLE
B.
1.
PRZM/
EXAMS
Input
Parameters
for
MCPB.

Season
year;
assumes
one
planting
season
per
year
Label
Spray
Application
Efficiencies
ground
aerial
0.99
0.95
EFED
Guidance,
2002
Spray
Drift
Fraction
ground
aerial
0.01
0.05
EFED
Guidance,
2002
Aerobic
Soil
Metabolism
t
½
78
days
1
estimated
upper
90
th
percentile
MRID
43247601
Anaerobic
Soil
Metabolism
t
½
34
days
2
estimated
upper
90
th
percentile
MRID
43015501
Aerobic
Aquatic
Degradation
t
½
156
days
3
estimated
(
2x
aerobic
soil
metabolism
half­
life)
EFED
Guidance,
2002
Anaerobic
Aquatic
Degradation
t
½
68
days
4
estimated
(
2x
anaerobic
soil
metabolism
half­
life)
EFED
Guidance,
2002
Aqueous
Photolysis
t
½
2.6
days
pH
7
MRID
42574302
Hydrolysis
t
½
stable
MRID
42574301
Kd/
Koc
0.85
mL/
g
5
Average
Kd
MRID
42693701
Molecular
Weight
228.6
Chemical
Formula
Water
Solubility
600
mg/
L
10
x
solubility
Product
Chemistry
Vapor
Pressure
4.0E­
7
torr
Product
Chemistry
Henry's
Law
Constant
(
estimated
at
25
°
C)
3.42
x
10­
9
atmm3
mol
(
Howard
and
Meylan,
1997)

1
Upper
90th
Percentile
based
on
three
times
the
single
value
for
the
combined/
total
aerobic
soil
metabolism
half
life
of
26
days
for
MCPB,
MCPA,
and
CHPA/
CHPA
hexose
conjugate.
2
Upper
90th
Percentile
based
on
three
times
the
single
anaerobic
soil
metabolism
half
life
of
11.4
days.
3
2x
aerobic
soil
metabolism
half­
life
(
EFED
Modeling
Input
Parameter
Guidance,
2002).
4
2x
anaerobic
soil
metabolism
half­
life
(
EFED
Modeling
Input
Parameter
Guidance,
2002).
5
From
adsorption/
desorption
data
including
Kd
values
of
1.69,
0.26,
0.65,
and
0.78
mL/
g
from
MRID
42693701.

TABLE
B.
2.
Estimated
Environmental
Concentrations
(
µ
g
ae/
L)
of
MCPB
+
Metabolites
(
MCPA
and
CHPA/
CHPA­
hexose)
in
Surface
Water
(
PRZM­
EXAMS)
from
All
Uses
for
Ecological
Assessment.

Simulation
Scenario
Concentration
(
µ
g
ae/
L)

Crop
and
Location
Application
rate
1
in
10
year
Peak
21
Day
Max.
60
Day
Max.

Lettuce
(
CA)
(
Surrogate
for
Peas)
1
.5
lbs
ae/
acre
(
1.68
kg
ae/
ha)
ground
spray
aerial
spray
40.4
43.2
39.0
41.7
36.4
38.9
(
Phase
III
3/
07/
06)
    
75
  
147
TABLE
B.
2.
Estimated
Environmental
Concentrations
(
µ
g
ae/
L)
of
MCPB
+
Metabolites
(
MCPA
and
CHPA/
CHPA­
hexose)
in
Surface
Water
(
PRZM­
EXAMS)
from
All
Uses
for
Ecological
Assessment.

Simulation
Scenario
Concentration
(
µ
g
ae/
L)

Crop
and
Location
Application
rate
1
in
10
year
Peak
21
Day
Max.
60
Day
Max.

Snap
Beans
(
OR)
(
Surrogate
for
Peas)
1.5
lbs
ae/
acre
(
1.68
kg
ae/
ha)
ground
spray
aerial
spray
29.5
33.1
29.0
32.5
28.1
31.5
The
following
surrogate
scenarios
are
among
those
available
in
PRZM/
EXAMS
to
simulate
peas
grown
in
different
regions
of
the
US:
California
lettuce
scenario
represents
a
reasonable
upper
bound
estimate
for
areas
in
which
peasare
or
may
be
grown.
Oregon
snap
bean
scenario
represents
a
typical
use
scenario
for
areas
in
which
peas
are
grown.

TABLE
B.
3.
Prism/
Exams
Output
California
Lettuce
Scenario
Aerial
Application
(
Phase
III
3/
07/
06)
    
76
  
147
stored
as
MCPBCAa1.
o
ut
Chemical:
MCPB_
CA_
lettuce_
NEW_
aerial
PRZM
environment:
CAlettuceC.
tx
t
modified
Monday,
11
October
2004
at
16:
23:
40
EXAMS
environment:
pond298.
exv
modified
Thuday,
29
August
2002
at
16:
33:
30
Metfile:
w23273.
dvf
modified
Wedday,
3
July
2002
at
09:
04:
22
Water
segment
concentrations
(
ppb)

Year
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
1961
4.2
4.154
4.051
3.799
3.598
2.235
1962
7.448
7.396
7.179
6.72
6.385
4.147
1963
24.08
23.9
23.18
22.21
21.21
12.61
1964
15.23
15.12
14.82
14.03
13.37
9.328
1965
8.774
8.711
8.525
8.26
7.947
5.532
1966
6.675
6.625
6.416
5.967
5.65
3.851
1967
9.819
9.748
9.562
9.12
8.687
5.602
1968
13.05
12.94
12.55
11.75
11.11
6.992
1969
10.97
10.88
10.52
9.773
9.254
6.351
1970
29.48
29.23
28.21
26.09
24.69
14.91
1971
11.81
11.73
11.37
10.77
10.42
8.076
1972
7.908
7.846
7.591
7.05
6.668
4.785
1973
11.5
11.45
11.11
10.35
9.881
6.413
1974
45.33
45.09
44.28
41.48
39.31
23.36
1975
25.37
25.19
24.46
22.86
21.7
14.91
1976
16.15
16.03
15.51
14.69
14.09
9.64
1977
20.08
19.92
19.27
18.11
17.72
11.5
1978
30.72
30.48
29.77
27.78
26.28
16.12
1979
12.8
12.74
12.38
11.89
11.47
8.159
1980
11.46
11.37
11.05
10.29
9.765
6.318
Year
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
1981
47.84
47.48
46.21
43.17
40.99
23.96
1982
17.61
17.49
17.07
16.2
15.56
11.28
1983
23.98
23.83
23.12
21.61
20.49
12.42
1984
10.05
9.973
9.658
9.242
8.776
5.989
1985
7.51
7.455
7.232
6.807
6.468
4.185
1986
18.29
18.17
17.72
16.68
15.83
9.474
1987
44.61
44.39
43.06
40.08
37.91
22.61
1988
19.15
19.01
18.5
17.25
16.29
12.38
1989
10.12
10.07
9.77
9.091
8.599
6.005
1990
6.794
6.744
6.54
6.095
5.776
3.858
Sorted
results
Prob.
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
0.032258065
47.84
47.48
46.21
43.17
40.99
23.96
0.064516129
45.33
45.09
44.28
41.48
39.31
23.36
0.096774194
44.61
44.39
43.06
40.08
37.91
22.61
(
Phase
III
3/
07/
06)
    
77
  
147
0.129032258
30.72
30.48
29.77
27.78
26.28
16.12
0.161290323
29.48
29.23
28.21
26.09
24.69
14.91
0.193548387
25.37
25.19
24.46
22.86
21.7
14.91
0.225806452
24.08
23.9
23.18
22.21
21.21
12.61
0.258064516
23.98
23.83
23.12
21.61
20.49
12.42
0.290322581
20.08
19.92
19.27
18.11
17.72
12.38
0.322580645
19.15
19.01
18.5
17.25
16.29
11.5
0.35483871
18.29
18.17
17.72
16.68
15.83
11.28
0.387096774
17.61
17.49
17.07
16.2
15.56
9.64
0.419354839
16.15
16.03
15.51
14.69
14.09
9.474
0.451612903
15.23
15.12
14.82
14.03
13.37
9.328
0.483870968
13.05
12.94
12.55
11.89
11.47
8.159
0.516129032
12.8
12.74
12.38
11.75
11.11
8.076
0.548387097
11.81
11.73
11.37
10.77
10.42
6.992
0.580645161
11.5
11.45
11.11
10.35
9.881
6.413
0.612903226
11.46
11.37
11.05
10.29
9.765
6.351
0.64516129
10.97
10.88
10.52
9.773
9.254
6.318
0.677419355
10.12
10.07
9.77
9.242
8.776
6.005
0.709677419
10.05
9.973
9.658
9.12
8.687
5.989
0.741935484
9.819
9.748
9.562
9.091
8.599
5.602
0.774193548
8.774
8.711
8.525
8.26
7.947
5.532
0.806451613
7.908
7.846
7.591
7.05
6.668
4.785
0.838709677
7.51
7.455
7.232
6.807
6.468
4.185
0.870967742
7.448
7.396
7.179
6.72
6.385
4.147
0.903225806
6.794
6.744
6.54
6.095
5.776
3.858
0.935483871
6.675
6.625
6.416
5.967
5.65
3.851
0.967741935
4.2
4.154
4.051
3.799
3.598
2.235
0.1
43.221
42.999
41.731
38.85
36.747
21.96
1
Average
of
yearly
averages:
9.766
667
Inputs
generated
by
pe4.
pl
­
8­
August­
2003
Data
used
for
this
run:
Output
File:
MCPBCAa1
Metfile:
w23273.
dvf
PRZM
scenario:
CAlettuceC.
t
xt
EXAMS
environment
file:
pond298.
exv
Chemical
Name:
MCPB_
CA_
lettuce_
NEW_
aerial
Description
Variable
Name
Value
Units
Comments
Molecular
weight
mwt
228.6
g/
mol
Henry's
Law
Const.
henry
3.42E­
09
atm­
m^
3/
mol
(
Phase
III
3/
07/
06)
    
78
  
147
Vapor
Pressure
vapr
4.00E­
07
torr
Solubility
sol
600
mg/
L
Kd
Kd
0.85
mg/
L
Koc
Koc
mg/
L
Photolysis
half­
life
kdp
2.6
days
Half­
life
Aerobic
Aquatic
Metabolism
kbacw
156
days
Halfife
Anaerobic
Aquatic
Metabolism
kbacs
68
days
Halfife
Aerobic
Soil
Metabolism
asm
78
days
Halfife
Hydrolysis:
pH
7
0
days
Half­
life
Method:
CAM
1
integer
See
PRZM
manual
Incorporation
Depth:
DEPI
0
cm
Application
Rate:
TAPP
1.68
kg/
ha
Application
Efficiency:
APPEFF
0.95
fraction
Spray
Drift
DRFT
0.05
fraction
of
application
rate
applied
to
pond
Application
Date
Date
3­
Jan
dd/
mm
or
dd/
mmm
or
dd­
mm
or
ddmmm
Record
17:
FILTRA
IPSCND
1
UPTKF
Record
18:
PLVKRT
PLDKRT
FEXTRC
0.5
Flag
for
Index
Res.
Run
IR
Pond
Flag
for
runoff
calc.
RUNOFF
none
none,
monthly
or
total(
average
of
entire
run)
(
Phase
III
3/
07/
06)
    
79
  
147
TABLE
B.
4.
Prism/
Exams
Output
California
Lettuce
Scenario
Ground
Application
stored
as
MCPBCAg1.
out
Chemical:
MCPB_
CA_
lettuce_
NEW_
ground
PRZM
environment:
CAlettuceC.
txt
modified
Monday,
11
October
2004
at
16:
23:
40
EXAMS
environment:
pond298.
exv
modified
Thuday,
29
August
2002
at
16:
33:
30
Metfile:
w23273.
dvf
modified
Wedday,
3
July
2002
at
09:
04:
22
Water
segment
concentrations
(
ppb)

Year
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
1961
2.02
2.008
1.949
1.406
1.06
0.6341
1962
3.426
3.402
3.304
3.081
2.919
1.995
1963
20.89
20.73
20.1
19.2
18.35
10.65
1964
11.66
11.57
11.27
10.71
10.21
7.169
1965
4.57
4.546
4.469
4.335
4.227
3.181
1966
2.199
2.183
2.116
1.972
1.869
1.471
1967
5.77
5.728
5.612
5.408
5.165
3.271
1968
9.071
9
8.728
8.212
7.771
4.791
1969
7.345
7.287
7.046
6.54
6.191
4.118
1970
26.08
25.85
24.95
23.06
21.79
13.06
1971
8.319
8.262
8.024
7.522
7.411
5.876
1972
3.499
3.473
3.364
3.131
3.072
2.473
1973
7.576
7.542
7.32
6.806
6.437
4.151
1974
42.5
42.29
41.57
38.96
36.93
21.79
1975
21.81
21.65
21.03
19.66
18.67
12.97
1976
12.12
12.03
11.65
11.11
10.7
7.54
1977
16.53
16.4
15.85
14.95
14.76
9.52
1978
27.41
27.19
26.6
24.83
23.49
14.34
1979
9.092
9.046
8.786
8.236
7.981
6.015
1980
7.354
7.298
7.085
6.607
6.276
4.096
1981
45.23
44.89
43.69
40.82
38.72
22.5
1982
13.96
13.86
13.53
12.7
12.48
9.261
1983
20.3
20.17
19.58
18.31
17.35
10.48
1984
6.079
6.034
5.845
5.528
5.353
3.885
1985
3.34
3.316
3.218
3
2.85
1.964
1986
14.67
14.57
14.21
13.34
12.67
7.416
1987
41.87
41.67
40.42
37.63
35.59
21.06
1988
16.17
16.05
15.6
14.55
13.75
10.44
1989
6.001
5.961
5.795
5.463
5.496
3.79
1990
2.415
2.398
2.328
2.173
2.065
1.571
Sorted
results
Prob.
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
(
Phase
III
3/
07/
06)
    
80
  
147
0.032258
45.23
44.89
43.69
40.82
38.72
22.5
0.064516
42.5
42.29
41.57
38.96
36.93
21.79
0.096774
41.87
41.67
40.42
37.63
35.59
21.06
0.129032
27.41
27.19
26.6
24.83
23.49
14.34
0.16129
26.08
25.85
24.95
23.06
21.79
13.06
0.193548
21.81
21.65
21.03
19.66
18.67
12.97
0.225806
20.89
20.73
20.1
19.2
18.35
10.65
0.258065
20.3
20.17
19.58
18.31
17.35
10.48
Prob.
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
0.290323
16.53
16.4
15.85
14.95
14.76
10.44
0.322581
16.17
16.05
15.6
14.55
13.75
9.52
0.354839
14.67
14.57
14.21
13.34
12.67
9.261
0.387097
13.96
13.86
13.53
12.7
12.48
7.54
0.419355
12.12
12.03
11.65
11.11
10.7
7.416
0.451613
11.66
11.57
11.27
10.71
10.21
7.169
0.483871
9.092
9.046
8.786
8.236
7.981
6.015
0.516129
9.071
9
8.728
8.212
7.771
5.876
0.548387
8.319
8.262
8.024
7.522
7.411
4.791
0.580645
7.576
7.542
7.32
6.806
6.437
4.151
0.612903
7.354
7.298
7.085
6.607
6.276
4.118
0.645161
7.345
7.287
7.046
6.54
6.191
4.096
0.677419
6.079
6.034
5.845
5.528
5.496
3.885
0.709677
6.001
5.961
5.795
5.463
5.353
3.79
0.741935
5.77
5.728
5.612
5.408
5.165
3.271
0.774194
4.57
4.546
4.469
4.335
4.227
3.181
0.806452
3.499
3.473
3.364
3.131
3.072
2.473
0.83871
3.426
3.402
3.304
3.081
2.919
1.995
0.870968
3.34
3.316
3.218
3
2.85
1.964
0.903226
2.415
2.398
2.328
2.173
2.065
1.571
0.935484
2.199
2.183
2.116
1.972
1.869
1.471
0.967742
2.02
2.008
1.949
1.406
1.06
0.6341
0.1
40.424
40.22
2
39.038
36.35
34.38
20.388
Average
of
yearly
averages:
7.715937
Inputs
generated
by
pe4.
pl
­
8­
August­
2003
Data
used
for
this
run:
Output
File:
MCPBCAg1
Metfile:
w23273.
d
vf
PRZM
scenario:
CAlettuceC.
txt
EXAMS
environment
file:
pond298.
exv
Chemical
Name:
MCPB_
CA_
lettuce_
NEW_
ground
Description
Variable
Name
Value
Units
Comment
s
Molecular
weight
mwt
228.6
g/
mol
Henry's
Law
Const.
henry
3.42E
­
09
atm­
m^
3/
mol
Vapor
Pressure
vapr
4.00E
­
07
torr
(
Phase
III
3/
07/
06)
    
81
  
147
Solubility
sol
600
mg/
L
Kd
Kd
0.85
mg/
L
Koc
Koc
mg/
L
Photolysis
halflife
kdp
2.6
days
Half­
life
Aerobic
Aquatic
Metabolism
kbacw
156
days
Halfife
Anaerobic
Aquatic
Metabolism
kbacs
68
days
Halfife
Aerobic
Soil
Metabolism
asm
78
days
Halfife
Hydrolysis:
pH
7
0
days
Half­
life
Method:
CAM
1
integer
See
PRZM
manual
Incorporation
Depth:
DEPI
0
cm
Application
Rate:
TAPP
1.68
kg/
ha
Application
Efficiency:
APPEFF
0.99
fraction
Spray
Drift
DRFT
0.01
fraction
of
application
rate
applied
to
pond
Application
Date
Date
3­
Jan
dd/
mm
or
dd/
mmm
or
dd­
mm
or
dd­
mmm
Record
17:
FILTRA
IPSCND
1
UPTKF
Record
18:
PLVKRT
PLDKRT
FEXTRC
0.5
Flag
for
Index
Res.
Run
IR
Pond
Flag
for
runoff
calc.
RUNOFF
none
none,
monthly
or
total(
average
of
entire
run)
(
Phase
III
3/
07/
06)
    
82
  
147
TABLE
B.
5.
Prism/
Exams
Output
Oregon
Bean
Scenario
Aerial
Application
stored
as
MCPBORa1.
out
Chemical:
MCPB_
OR_
snapbean_
NEW_
aerial
PRZM
environme
nt:
ORsnbean
sC.
txt
modified
Satday,
12
October
2002
at
17:
20:
58
EXAMS
environme
nt:
pond298.
e
xv
modified
Thuday,
29
August
2002
at
16:
33:
30
Metfile:
w24232.
dv
f
modified
Wedday,
3
July
2002
at
09:
06:
10
Water
segment
concentrations
(
ppb)

Year
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
1961
39.96
39.78
39.16
37.25
35.7
21.12
1962
18.43
18.33
18.14
17.61
16.99
12.51
1963
14.98
14.93
14.63
13.96
13.54
9.535
1964
19.47
19.39
19
18.24
17.57
11.51
1965
11.6
11.54
11.27
10.96
10.78
7.885
1966
25.77
25.62
25.15
23.75
22.71
14.12
1967
15.06
15.02
14.75
14.05
13.54
9.435
1968
13.02
12.94
12.71
12.06
11.56
7.818
1969
13.17
13.09
12.82
12.24
11.68
7.82
1970
16.94
16.87
16.49
15.74
15.1
9.766
1971
25.85
25.76
25.26
24.12
23.23
14.93
1972
37.5
37.38
37.06
35.37
33.94
21.53
1973
27.86
27.71
27.48
26.45
25.38
17.23
1974
23.75
23.63
23.19
22.04
21.21
14.33
1975
16.66
16.6
16.26
15.44
14.77
10.37
1976
13.63
13.56
13.28
12.59
12.04
8.439
1977
17.95
17.89
17.56
16.63
15.94
10.31
1978
11.13
11.06
10.9
10.42
10.19
7.179
1979
22.32
22.18
21.7
20.53
19.61
12.14
1980
19.67
19.56
19.2
18.16
17.4
11.71
1981
33.45
33.25
32.84
31.87
30.68
19.47
1982
27.84
27.73
27.31
26.01
24.93
16.67
1983
26.25
26.13
25.62
24.29
23.2
15.34
1984
16.72
16.67
16.35
15.53
14.89
10.52
1985
14.75
14.7
14.4
13.62
13
8.816
1986
22.81
22.67
22.37
21.61
20.74
13.1
1987
21.24
21.12
20.74
19.77
18.92
12.39
1988
15.01
14.92
14.63
14.23
13.71
9.378
1989
29.8
29.68
29.33
27.86
26.6
16.58
1990
22.58
22.49
22.01
20.78
19.9
13.45
(
Phase
III
3/
07/
06)
    
83
  
147
Sorted
results
Prob.
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
0.032258
39.96
39.78
39.16
37.25
35.7
21.53
0.064516
37.5
37.38
37.06
35.37
33.94
21.12
0.096774
33.45
33.25
32.84
31.87
30.68
19.47
0.129032
29.8
29.68
29.33
27.86
26.6
17.23
0.16129
27.86
27.73
27.48
26.45
25.38
16.67
0.193548
27.84
27.71
27.31
26.01
24.93
16.58
0.225806
26.25
26.13
25.62
24.29
23.23
15.34
Prob.
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
0.258065
25.85
25.76
25.26
24.12
23.2
14.93
0.290323
25.77
25.62
25.15
23.75
22.71
14.33
0.322581
23.75
23.63
23.19
22.04
21.21
14.12
0.354839
22.81
22.67
22.37
21.61
20.74
13.45
0.387097
22.58
22.49
22.01
20.78
19.9
13.1
0.419355
22.32
22.18
21.7
20.53
19.61
12.51
0.451613
21.24
21.12
20.74
19.77
18.92
12.39
0.483871
19.67
19.56
19.2
18.24
17.57
12.14
0.516129
19.47
19.39
19
18.16
17.4
11.71
0.548387
18.43
18.33
18.14
17.61
16.99
11.51
0.580645
17.95
17.89
17.56
16.63
15.94
10.52
0.612903
16.94
16.87
16.49
15.74
15.1
10.37
0.645161
16.72
16.67
16.35
15.53
14.89
10.31
0.677419
16.66
16.6
16.26
15.44
14.77
9.766
0.709677
15.06
15.02
14.75
14.23
13.71
9.535
0.741935
15.01
14.93
14.63
14.05
13.54
9.435
0.774194
14.98
14.92
14.63
13.96
13.54
9.378
0.806452
14.75
14.7
14.4
13.62
13
8.816
0.83871
13.63
13.56
13.28
12.59
12.04
8.439
0.870968
13.17
13.09
12.82
12.24
11.68
7.885
0.903226
13.02
12.94
12.71
12.06
11.56
7.82
0.935484
11.6
11.54
11.27
10.96
10.78
7.818
0.967742
11.13
11.06
10.9
10.42
10.19
7.179
0.1
33.085
32.893
32.489
31.469
30.272
19.24
6
Average
of
yearly
averages
:
12.51
337
Inputs
generated
by
pe4.
pl
­
8­
August­
2003
Data
used
for
this
run:
Output
File:
MCPBORa1
Metfile:
w24232.
dvf
PRZM
scenario:
ORsnbeansC.
txt
EXAMS
environme
nt
file:
pond298.
exv
Chemical
Name:
MCPB_
OR_
snapbean_
NEW_
aerial
Descriptio
Variable
Value
Units
Comme
(
Phase
III
3/
07/
06)
    
84
  
147
n
Name
nts
Molecular
weight
mwt
228.6
g/
mol
Henry's
Law
Const.
henry
3.42E­
09
atm­
m^
3/
mol
Vapor
Pressure
vapr
4.00E­
07
torr
Solubility
sol
600
mg/
L
Kd
Kd
0.85
mg/
L
Koc
Koc
mg/
L
Photolysis
half­
life
kdp
2.6
days
Half­
life
Aerobic
Aquatic
Metabolis
m
kbacw
156
days
Halfife
Anaerobic
Aquatic
Metabolis
m
kbacs
68
days
Halfife
Aerobic
Soil
Metabolis
m
asm
78
days
Halfife
Hydrolysis:
pH
7
0
days
Half­
life
Method:
CAM
1
integer
See
PRZM
manual
Incorporati
on
Depth:
DEPI
0
cm
Application
Rate:
TAPP
1.68
kg/
ha
Application
Efficiency:
APPEFF
0.95
fraction
Spray
Drift
DRFT
0.05
fraction
of
application
rate
applied
to
pond
Application
Date
Date
3­
Jan
dd/
mm
or
dd/
mmm
or
dd­
mm
or
dd­
mmm
Record
17:
FILTRA
IPSCND
1
UPTKF
Record
18:
PLVKRT
PLDKRT
FEXTRC
0.5
Flag
for
Index
Res.
Run
IR
Pond
Flag
for
runoff
calc.
RUNOFF
none
none,
monthly
or
total(
average
of
entire
run)
(
Phase
III
3/
07/
06)
    
85
  
147
TABLE
B.
6.
Prism/
Exams
Output
Oregon
Bean
Scenario
Ground
Application
stored
as
MCPBORg1.
out
Chemical:
MCPB_
OR_
snapbean_
NEW_
ground
PRZM
environment:
ORsnbeans
C.
txt
modified
Satday,
12
October
2002
at
17:
20:
58
EXAMS
environment:
pond298.
exv
modified
Thuday,
29
August
2002
at
16:
33:
30
Metfile:
w24232.
dvf
modified
Wedday,
3
July
2002
at
09:
06:
10
Water
segment
concentrations
(
ppb)

Year
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
1961
38.19
38.03
37.42
35.6
34.13
20.18
1962
14.67
14.6
14.45
14.07
13.64
10.39
1963
10.95
10.91
10.69
10.17
9.749
6.991
1964
15.25
15.19
14.89
14.27
13.72
8.96
1965
7.58
7.536
7.367
6.997
6.81
5.206
1966
21.78
21.65
21.28
20.09
19.18
11.74
1967
10.75
10.72
10.54
10.05
9.628
6.903
1968
8.725
8.677
8.52
8.086
7.741
5.231
1969
8.776
8.722
8.571
8.214
7.847
5.177
1970
12.65
12.59
12.3
11.78
11.3
7.21
1971
21.89
21.81
21.38
20.37
19.62
12.52
1972
33.99
33.89
33.56
32.05
30.76
19.42
1973
23.96
23.84
23.61
22.78
21.87
14.96
1974
19.74
19.64
19.26
18.31
17.58
11.93
1975
12.44
12.41
12.17
11.55
11.05
7.803
1976
9.316
9.275
9.087
8.601
8.231
5.754
1977
13.61
13.57
13.33
12.63
12.1
7.728
1978
6.75
6.713
6.64
6.389
6.113
4.515
1979
18.1
17.98
17.58
16.64
15.9
9.694
1980
15.53
15.45
15.17
14.36
13.74
9.225
1981
29.9
29.72
29.41
28.5
27.46
17.31
1982
23.87
23.76
23.44
22.35
21.43
14.41
1983
22.33
22.23
21.82
20.68
19.75
13.03
1984
12.52
12.48
12.24
11.64
11.16
7.997
1985
10.54
10.5
10.27
9.716
9.274
6.221
1986
18.96
18.84
18.42
17.9
17.19
10.72
1987
17.17
17.08
16.76
15.93
15.27
10.03
1988
10.93
10.87
10.65
10.28
9.931
6.886
1989
26.1
25.99
25.65
24.39
23.29
14.36
(
Phase
III
3/
07/
06)
    
86
  
147
1990
18.53
18.46
18.08
17.07
16.33
11.11
Sorted
results
Prob.
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
0.032258
38.19
38.03
37.42
35.6
34.13
20.18
0.064516
33.99
33.89
33.56
32.05
30.76
19.42
0.096774
29.9
29.72
29.41
28.5
27.46
17.31
0.129032
26.1
25.99
25.65
24.39
23.29
14.96
0.16129
23.96
23.84
23.61
22.78
21.87
14.41
0.193548
23.87
23.76
23.44
22.35
21.43
14.36
0.225806
22.33
22.23
21.82
20.68
19.75
13.03
0.258065
21.89
21.81
21.38
20.37
19.62
12.52
0.290323
21.78
21.65
21.28
20.09
19.18
11.93
Prob.
Peak
96
hr
21
Day
60
Day
90
Day
Yearly
0.322581
19.74
19.64
19.26
18.31
17.58
11.74
0.354839
18.96
18.84
18.42
17.9
17.19
11.11
0.387097
18.53
18.46
18.08
17.07
16.33
10.72
0.419355
18.1
17.98
17.58
16.64
15.9
10.39
0.451613
17.17
17.08
16.76
15.93
15.27
10.03
0.483871
15.53
15.45
15.17
14.36
13.74
9.694
0.516129
15.25
15.19
14.89
14.27
13.72
9.225
0.548387
14.67
14.6
14.45
14.07
13.64
8.96
0.580645
13.61
13.57
13.33
12.63
12.1
7.997
0.612903
12.65
12.59
12.3
11.78
11.3
7.803
0.645161
12.52
12.48
12.24
11.64
11.16
7.728
0.677419
12.44
12.41
12.17
11.55
11.05
7.21
0.709677
10.95
10.91
10.69
10.28
9.931
6.991
0.741935
10.93
10.87
10.65
10.17
9.749
6.903
0.774194
10.75
10.72
10.54
10.05
9.628
6.886
0.806452
10.54
10.5
10.27
9.716
9.274
6.221
0.83871
9.316
9.275
9.087
8.601
8.231
5.754
0.870968
8.776
8.722
8.571
8.214
7.847
5.231
0.903226
8.725
8.677
8.52
8.086
7.741
5.206
0.935484
7.58
7.536
7.367
6.997
6.81
5.177
0.967742
6.75
6.713
6.64
6.389
6.113
4.515
0.1
29.52
29.347
29.034
28.089
27.043
17.075
Average
of
yearly
average
s:
10.1203
7
Inputs
generated
by
pe4.
pl
­
8­
August­
2003
Data
used
for
this
run:
Output
File:
MCPBORg1
Metfile:
w24232.
dvf
PRZM
scenario:
ORsnbeansC.
txt
EXAMS
environment
file:
pond298.
exv
Chemical
Name:
MCPB_
OR_
snapbean_
NEW_
gro
und
(
Phase
III
3/
07/
06)
    
87
  
147
Description
Variable
Name
Value
Units
Comm
ents
Molecular
weight
mwt
228.6
g/
mol
Henry's
Law
Const.
henry
3.42E­
09
atm­
m^
3/
mol
Vapor
Pressure
vapr
4.00E­
07
torr
Solubility
sol
600
mg/
L
Kd
Kd
0.85
mg/
L
Koc
Koc
mg/
L
Photolysis
half­
life
kdp
2.6
days
Halflife
Aerobic
Aquatic
Metabolism
kbacw
156
days
Halfife
Anaerobic
Aquatic
Metabolism
kbacs
68
days
Halfife
Aerobic
Soil
Metabolism
asm
78
days
Halfife
Hydrolysis:
pH
7
0
days
Halflife
Method:
CAM
1
integer
See
PRZM
manual
Incorporation
Depth:
DEPI
0
cm
Application
Rate:
TAPP
1.68
kg/
ha
Application
Efficiency:
APPEFF
0.99
fraction
Spray
Drift
DRFT
0.01
fraction
of
application
rate
applied
to
pond
Application
Date
Date
3­
Jan
dd/
mm
or
dd/
mmm
or
dd­
mm
or
dd­
mmm
Record
17:
FILTRA
IPSCND
1
UPTKF
Record
18:
PLVKR
T
PLDKR
T
FEXTR
C
0.5
Flag
for
Index
Res.
Run
IR
Pond
Flag
for
runoff
calc.
RUNOF
F
none
none,
monthly
or
total(
average
of
entire
run)
(
Phase
III
3/
07/
06)
    
88
  
147
APPENDIX
C:
Terrestrial
Bird
and
Mammal
TREX
Version
1.1
Model
Results
(
Phase
III
3/
07/
06)
    
89
  
147
TREX
(
Version1.1)

As
part
of
the
terrestrial
assessment,
EFED
modeled
exposure
concentrations
of
MCPB
to
non­
target
animals
following
the
proposed
application
rates
provided
by
the
registrant.
For
terrestrial
birds
and
mammals,
estimates
of
initial
levels
of
MCPB
residues
on
various
food
items,
which
may
be
contacted
or
consumed
by
wildlife,
were
determined
using
the
Kenega­
Fletcher
nomogram
followed
by
a
first
order
decline
model
TREX
1.1.
Upper
bound
Kenega­
Fletcher
values
were
used
for
RQ
calculations
(
Phase
III
3/
07/
06)
    
90
  
147
1.
Upper
Bound
Kenaga
Residues
for
RQ
Calculations
Birds
and
Mammals
TREX
Version
1.1
Model
(
May
25,
2005)

INPUT
VALUES
Chemical
Name:
MCPB
Use
Peas
Formulation
MCPB
sodium
salt
Application
Rate
1.5
lbs
a.
e./
acre
Half­
life
35
days
Application
Interval
1
days
Maximum
#
Apps./
Year
1
Length
of
Simulation
1
year
Concentration
of
Concern
0.00
(
ppm)
Name
of
Concentration
of
Concern
Avian
acute
LC50
Endpoints
Avian
Bobwhite
quail
LD50
(
mg/
kg­
bw)
257
Bobwhite
quail
LC50
(
mg/
kg­
diet)
Bobwhite
quail
NOAEL
(
mg/
kg­
bw)
0
Bobwhite
quail
NOAEC
(
mg/
kg­
diet)
1000
Mammals
LD50
(
mg/
kg­
bw)
832
LC50
(
mg/
kg­
diet)
0
NOAEL
(
mg/
kg­
bw)
4.56
NOAEC
(
mg/
kg­
diet)
91.2
EECs
(
ppm)
Kenaga
Values
Short
Grass
360
Tall
Grass
165
Broadleafplants/
sminsects
202.5
Fruits/
pods/
seeds/
lg
insects
22.50
(
Phase
III
3/
07/
06)
    
91
  
147
Avian
Results
Upper
Bound
Kenaga
Avian
Body
%
body
wgt
Adjusted
Class
Weight
consumed
LD50
Small
20
114
182
Mid
100
65
232
Large
1000
29
327
EEC
equivalent
dose
(
mg/
kg­
bw)
Avian
Classes
and
Body
Weights
small
mid
large
20
g
100
g
1000
g
Short
Grass
410
234
104
Tall
Grass
188
107
48
Broadleaf
plants/
sm
insects
231
132
59
Fruits/
pods/
lg
insects
26
15
7
Dose­
based
RQs
(
daily
dose/
LD50)
Avian
Acute
RQs
20
g
100
g
1000
g
Short
Grass
2.26
1.01
0.32
Tall
Grass
1.03
0.46
0.15
Broadleaf
plants/
sm
insects
1.27
0.57
0.18
Fruits/
pods/
lg
insects
0.14
0.06
0.02
Dietary­
based
RQs
(
dietary­
based
EEC/
LD50)
RQs
Acute
Chronic
Short
Grass
0.36
Tall
Grass
0.17
Broadleaf
plants/
sm
insects
0.20
Fruits/
pods/
lg
insects
0.02
(
Phase
III
3/
07/
06)
    
92
  
147
Mammalian
Results
Upper
Bound
Kenaga
Mammalian
Body
%
body
wgt
Adjusted
Adjusted
Class
Weight
consumed
LD50
NOAEL
15
95
1829
17
Herbivores/
35
66
1480
14
insectivores
1000
15
640
6
15
21
1829
10
Grainvores
35
15
1480
14
1000
3
640
6
EEC
equivalent
dose
(
mg/
kg­
bw)
Mammalian
Classes
and
Body
weight
Herbivores/
insectivores
Granivores
15
g
35
g
1000
g
15
g
35
g
1000
g
Short
Grass
342
238
54
Tall
Grass
157
109
25
Broadleaf
plants/
sm
Insects
192
134
30
Fruits/
pods/
seed/
lg
insects
21
15
3
5
3
1
Dose­
based
RQs
(
daily
dose/
LD50
or
NOAEL)
15
g
mammal
35
g
mammal
1000
g
mammal
Acute
Chronic
Acute
Chronic
Acute
Chronic
Short
Grass
0.19
19.94
0.16
17.12
0.08
9
Tall
Grass
0.09
9.14
0.07
7.85
0.04
4.12
Broadleaf
plants/
sm
insects
0.11
11.22
0.09
9.63
0.05
5.06
Fruits/
pods/
lg
insects
0.01
1.25
0.01
1.07
0.01
0.56
Seeds
(
granivore)
0.00
0.47
0
0.24
0.00
0.11
(
Phase
III
3/
07/
06)
    
93
  
147
2.
.
Mean
Kenaga
Residues
for
Risk
Characterization
only
Birds
and
Mammals
TREX
model
version
1.1
Avian
Results
Mean
Kenaga
Residues
Avian
Body
%
body
wgt
Adjusted
Class
Weight
consumed
LD50
Small
20
114
182
Mid
100
65
232
Large
1000
29
327
EEC
equivalent
dose
(
mg/
kg­
bw)
Avian
Classes
and
Body
Weights
small
mid
large
20
g
100
g
1000
g
Short
Grass
145
83
37
Tall
Grass
62
35
16
Broadleaf
plants/
sm
insects
77
44
20
Fruits/
pods/
lg
insects
12
7
3
Dose­
based
Rqs
(
daily
dose/
LD50)
Avian
Acute
RQs
20
g
100
g
1000
g
Short
Grass
0.8
0.36
0.11
Tall
Grass
0.34
0.15
0.05
Broadleaf
plants/
sm
insects
0.42
0.19
0.06
Fruits/
pods/
lg
insects
0.07
0.03
0.01
Dietary­
based
RQs
(
EEC/
LC50
or
NOAEC)
RQs
Acute
Chronic
Short
Grass
0.13
Tall
Grass
0.05
Broadleaf
plants/
sm
Insects
0.07
Fruits/
pods/
lg
insects
0.01
(
Phase
III
3/
07/
06)
    
94
  
147
Mammalian
Results
Mean
Kenaga
Residues
Mammalian
Body
%
body
wgt
Adjusted
Adjusted
Class
Weight
consumed
LD50
NOAEL
15
95
1829
19
Herbivores
35
66
1480
15
insectivores
1000
15
640
7
15
21
1829
19
Grainvores
35
15
1480
15
1000
3
640
4
EEC
equivalent
dose
(
mg/
kg­
bw)
Mammalian
Classes
and
Body
weight
Herbivores/
insectivores
Granivores
15
g
35
g
1000
g
15
g
35
g
1000
g
Short
Grass
121
84
19
Tall
Grass
51
36
8
Broadleafplants/
sm
Insects
64
45
10
Fruits/
pods/
seeds/
lg
insects
10
7
2
2
2
0
Dose­
based
RQs
(
daily
dose/
LD50
or
NOAEL)
15
g
mammal
35
g
mammal
1000
g
mammal
Acute
Chronic
Acute
Chronic
Acute
Chronic
Short
Grass
0.07
6.44
0.06
5.53
0.03
2.91
Tall
Grass
0.03
2.73
0.02
2.34
0.01
1.23
Broadleaf
plants/
sm
insects
0.04
3.41
0.03
2.93
0.02
1.54
Fruits/
pods/
lg
insects
0.01
0.53
0
0.46
0.00
0.24
Seeds
(
granivore)
0.00
0.12
0
0.1
0.00
0.08
APPENDIX
D:
TerrPlant
and
AgDrift
Model
and
Results
(
Phase
III
3/
07/
06)
    
96
  
147
TERRPLANT
MODEL
Version
1.0
Terrestrial
plant
exposure
characterization
employs
runoff
and
spray
drift
scenarios
contained
in
OPP s
Terrplant
model.
Exposure
calculations
are
based
on
a
pesticide s
water
solubility
and
the
amount
of
pesticide
present
on
the
surface
soil
within
the
first
inch
of
depth.
For
dry
areas,
the
loading
of
pesticide
active
ingredient
or
acid
equivalent
from
runoff
to
an
adjacent
non­
target
area
is
assumed
to
occur
from
one
acre
of
treatment
to
one
acre
of
non­
target
area.
For
terrestrial
plants
inhabiting
semi­
aquatic
(
wetland)
areas,
runoff
is
considered
to
occur
from
a
larger
source
area
with
active
ingredient
loading
originating
from
10
acres
of
treated
area
to
a
single
acre
of
non­
target
wetland.
Default
spray
drift
assumptions
are
1%
for
ground
applications
and
5%
for
aerial,
forced
air
(
i.
e.,
air
pressure
within
a
spray
tank
that
forces
the
spray
liquid
through
the
boom
nozzles),
and
chemigation
applications.
Predicted
EECs
resulting
from
spray
drift
and
aerial
applications
are
derived
for
non­
granular
applications
only.
Terrestrial
Plant
EECs
and
Acute
Non
Endangered
RQs
(
8/
8/
01;
version
1.0))
Chemical:
MCPB
Input
Values
Application
Rate
(
lb
a.
e./
acre)
1.5
Estimated
Environmental
Concentrations
(
EECs)
for
NON­
GRANULAR
formulation
applications
(
lbs
a.
i./
acre)
Risk
Quotients
(
RQs)
for
NON­
GRANULAR
formulation
applications
Runoff
Value
(
0.01,
0.02,
or
0.05
if
chemical
solubility
<
10,
10­

100,
or
>
100
ppm,

respectively)
0.05
Application
Method
Total
Loading
to
Adjacent
Areas
(
EEC
=
Sheet
Runoff
+
Drift)
Total
Loading
to
Semiaquatic
Areas
(
EEC
=
Channelize
d
Runoff
+

Drift)
DRIFT
EEC
(
for
ground:

application
rate
x
0.01)

(
for
aerial:
application
rate
x
0.05)
Emergence
RQs,

Adjacent
Areas
RQ
=
EEC/
Seedling
Emergence
EC25
Emergence
RQs,

Semiaquatic
Areas
RQ
=
EEC/
Seedling
Emergence
EC25
Drift
Rqs
RQ
=
Drift
EEC/
Vegetative
Vigor
EC25
Emergence
Minimum
Incorporation
Depth
(
inches)
0
Monocot
Dicot
Monocot
Dicot
Monocot
Dicot
Ground
Unincorp.
0.0900
0.765
0.0150
4.50
5.63
38.25
47.81
0.94
10
Seed
Emerg
Monocot
EC25
(
lb
a.
e./
acre)
0.02
Seed
Emerg
Dicot
EC25
(
lb
a.
e./
acre)
0.016
Aerial,

Airblast,
Spray
Chemigatio
n
0.1200
0.525
0.0750
6
7.50
26.25
32.81
4.69
50
Veg
Vigor
Monocot
EC25
(
lb
a.
e./
acre)
0.016
Veg
Vigor
Dicot
EC25
(
lb
a.
e./
acre)
0.002
Terrestrial
Plant
EECs
and
Acute
Endangered
RQs
(
8/
8/
01;
version
1.0)
Chemical:
MCPB
Input
Values
Application
Rate
(
lb
a.
e./
acre)
1.5
Estimated
Environmental
Concentrations
(
EECs)
for
NON­
GRANULAR
formulation
applications
(
lbs
a.
i./
acre)
Risk
Quotients
(
RQs)
for
NON­
GRANULAR
formulation
applications
Runoff
Value
(
0.01,
0.02,
or
0.05
if
chemical
solubility
<
10,
10­
100,
or
>
100
ppm,
respectively)
0.05
Application
Method
Total
Loading
to
Adjacent
Areas
(
EEC
=

Sheet
Runoff
+
Drift)
Total
Loading
to
Semiaquatic
Areas
(
EEC
=

(
Channelize
d
Runoff
+

Drift)
DRIFT
EEC
(
for
ground:

application
rate
x
0.01)
(
for
aerial:
application
rate
x
0.05)
Emergence
RQs,

Adjacent
Areas
RQ
=
EEC/
Seedling
Emergence
EC05
or
NOAEC
Emergence
RQs,

Semiaquatic
areas
RQ
=
EEC/
Seedling
Emergence
EC05
or
NOAEC
Drift
Rqs
RQ
=

EEC/
Vegetative
Vigor
EC05
or
NOAEC
Minimum
Incorporation
Depth
(
inches)
0
Monocot
Dicot
Monocot
Dicot
Monocot
Dicot
Ground
Unincorp.
0.0900
0.7650
0.0150
9.00
9.00
76.50
76.50
Seed
Emerg
Monocot
EC05
or
NOAEC
(
lb
a.
e./
acre)
0.01
Seed
Emerg
Dicot
EC05
or
NOAEC
(
lb
a.
e./
acre)
0.01
Aerial,

Airblast,
Spray
Chemigation
0.1200
0.5250
0.0750
12.00
12.00
52.50
52.50
Veg
Vigor
Monocot
EC05
or
NOAEC
(
lbs
a../
acre)
­­­­­­­­­

Veg
Vigor
Dicot
EC05
or
NOAEC
(
lb
a.
e./
acre)
­­­­­­­­­
(
Phase
III
3/
07/
06)
    
99
  
147
AGDRIFT
Model
(
Version
2.01)

The
AgDRIFT
model
(
Version
2.01)
was
used
to
refine
the
spray
drift
exposure
estimate
for
terrestrial
plants.
Downwind
spray
drift
buffers
were
developed
for
possible
use
in
mitigating
risks
for
endangered
terrestrial
plants
that
grow
in
close
proximity
to
agricultural
and
non­
agricultural
fields
that
may
be
treated
with
liquid
spray
applications
of
MCPB.
The
model
was
used
to
estimate
spray
buffer
distances
for
ground
and
aerial
application
to
reach
the
NOAEC
and
EC
25
doses
for
the
most
sensitive
monocot
and
dicot
species
in
the
seedling
emergence
and
the
vegetative
vigor
studies.
The
standard
toxicity
level
EFED
uses
for
calculating
risk
quotients
for
non­
endangered
terrestrial
plants
is
the
EC
25
.
For
endangered
plants,
the
NOAEC
(
or
EC
05
if
a
NOAEC
value
is
not
available)
is
used.
Seedling
emergence
endpoints
are
representative
of
exposure
through
soil
to
germinating
plants,
while
vegetative
vigor
endpoints
are
representative
of
foliar
exposure.
The
terrestrial
plant
measurement
endpoints
used
in
the
model
are
specified
in
Table
D­
1.

Aerial
Application
The
most
important
factors
affecting
drift
from
aerial
applications
are
spray
droplet
size,
release
height,
and
wind
speed.
The
aerial
part
of
the
AgDRIFT
model
predicts
mean
dissipation
distances
based
on
the
inputs
provided.
For
aerial
applications,
the
model
contains
three
tiers
of
increasing
complexity.
However,
only
Tier
1
Aerial
Model
was
used
to
estimate
spray
buffer
distances
for
an
initial
screening
.

Tier
I
Aerial
Modeling
The
AgDRIFT
Tier
I
model
for
aerial
application
limits
the
input
parameters
to
droplet
size
only.
The
output
of
the
Tier
I
AgDRIFT
model
provides
distances
required
to
dissipate
spray
drift
to
the
NOAEC
and
EC
25
levels.

An
analysis
of
the
results
indicates
exceedance
of
the
Acute
Risk
LOC
for
nonendangered
monocots
and
dicots
located
adjacent
to
treated
areas,
in
semi­
aquatic
areas,
and
as
a
result
of
spray
drift..
The
Endangered
Species
LOC
was
exceeded
for
monocots
and
dicots
located
in
dryland
and
semi­
aquatic
areas
adjacent
to
treated
areas
and
for
dicots
as
a
result
of
spray
drift.

In
spite
of
the
uncertainty
in
the
magnitude
of
the
EC
25
values
used
to
calculate
the
RQs
for
MCPB,
other
data
in
the
vegetative
vigor
studies
indicate
the
potential
for
risk
to
non­
target
dicots
from
spray
drift
alone.
Using
the
spray
drift
model
AgDrift,
the
distances
were
calculated
at
which
exposure
would
be
equivalent
to
the
lowest
application
rates
tested
in
the
vegetative
vigor
study
which
led
to
adverse
effects.
This
Tier
1
AgDrift
assessment
assumed
a
fine
to
medium
droplet
size
spectrum,
and
an
aerial
application.
Table
D
.2..
shows
these
rates
for
each
crop,
the
fraction
of
the
applied,
and
the
distance
at
which
that
deposition
would
occur.
(
Phase
III
3/
07/
06)
    
100
  
147
Highly
active
herbicides,
such
as
the
growth
regulators,
present
the
greatest
drift
hazard
because
extremely
small
amounts
can
cause
severe
problems.
Even
if
only
a
small
surface
area
of
the
plant
is
exposed
to
MCPB,
or
a
seedling
is
exposed
to
MCPB
as
it
breaks
through
the
soil
surface,
there
is
a
possibility
that
the
plant
may
be
severely
damaged
or
die
as
a
result.
In
the
vegetative
vigor
test,
effects
observed
included
mortality
(
one
cucmber
plant,
two
radish
plants),
leaf
necrosis,
decreased
plant
size,
leaf
curl,
and
stem
tumors.
Such
damage,
even
if
only
minor,
may
be
sufficient
to
prevent
the
plant
from
competing
successfully
with
other
plants
for
resources
and
water.
However,
since
the
vegetative
vigor
tests
could
not
determine
a
no­
effect
application
rate
for
MCPB,
the
effectiveness
of
these
buffers
to
eliminate
risk
to
plants
cannot
be
evaluated.

TABLE
D.
2.
Input
and
Output
Parameters
AGDRIFT
to
Estimate
Distance
of
Deposition
of
MCPB
Equivalent
to
Rates
Tested
in
Vegetative
Vigor
Study
Crop
input
parameter
initial
average
disposition
(
lb
ae/
acre)
input
parameter
active
rate
lb
ae/
acre
output
parameter
fraction
of
the
applied
output
parameter
Distance
of
Deposition
Cabbage
0.08
1.5
0.0533
177
Lettuce
0.039
1.5
0.026
361
Soybean
0.17
1.5
0.1134
85
Tomato
0.08
1.5
0.0533
177
APPENDIX
E:
Ecological
Effects
Data
(
Phase
III
3/
07/
06)
    
102
  
147
Ecological
Effects
Data
71­
1
Avian
Acute
Oral
Bobwhite
Quail.
MRID
42560801
(
Acceptable).
In
a
14­
day
oral
gavage
study,
MCPB
sodium
was
determined
to
be
moderately
toxic
to
bobwhite
quail
with
an
LD
50
of
282
mg
ai/
kg
(
95%
confidence
interval
241­
330
mg
ai/
kg).
The
NOEL
was
not
determined
due
to
abnormal
effects
at
the
lowest
test
level.
The
study
is
scientifically
sound
and
follows
the
guideline
protocols.
Study
design:
10
birds,
five
males
and
five
females
were
assigned
to
each
treatment
level,
including
the
controls.
Observations
for
mortality
and
sublethal
effects
were
made
once
a
day
for
14
days
post
dosing.
Body
weights
were
measured
at
test
initiation,
and
on
days
3,
7,
and
14.
Average
estimated
feed
consumption
was
determined
for
each
group
for
days
0­
3,
4­
7,
and
8­
14.
Reported
results:
Bobwhite
were
exposed
to
six
nominal
concentrations
of
MCPB:
0,
147,
215,
316,
464
and
681
mg
ai/
kg.
There
were
10
mortalities
(
100%)
at
the
681
level,
9
at
464
level,
6
at
316
level,
2
at
215
level
and
1
at
147
level.
Signs
of
toxicity
were
observed
at
all
test
groups.
Birds
in
the
681mg/
kg
group
appeared
lethargic,
and
exhibited
dyspnea
(
gasping),
loss
of
righting
reflex
and
diarrhea.
Birds
in
the
other
treatment
groups
exhibited
lethargy
and
diarrhea.
Gross
necropsis
were
performed
on
all
28
birds
that
died
and
all
showed
abnormalities
such
as;
white
areas
and
or
white
film
on
the
heart,
liver,
gizzard,
gallbladder,
crop
or
intestines.
Also
clear
fluid
from
the
beak
was
observed.

71­
2
Avian
Acute
Dietary
Bobwhite
Quail.
MRID
42560802
(
Acceptable).
In
an
8­
day
dietary
study,
MCPB
sodium
was
determined
to
be
practically
non­
toxic
to
bobwhite
quail
with
an
LC
50
>
5000
ppm
ai
(
nominal
concentration).
The
NOEL
was
1250
ppm
ai
(
nominal
concentration).
The
study
is
scientifically
sound
and
generally
followed
guideline
protocols.
Study
design:
Ten
birds
were
assigned
to
each
treatment
level,
including
five
vehicle
control
groups.
Reported
Results:
Bobwhite
were
exposed
to
five
nominal
concentrations
of
MCPBNA
312,
625,
1250,
2500
and
5000
ppm.
There
were
no
mortalities
at
any
test
level
or
in
control
groups.
There
were
no
clinical
signs
of
toxicity
at
any
test
level.
The
gross
necropsis
revealed
abnormal
findings
in
2
birds.
Three
white
spots
were
present
on
the
liver
of
1
bird
in
the
1250
ppm
ai
group
and
a
dark
red
spot
was
found
on
the
liver
at
the
5000
ppm
ai
group.

Mallard.
MRID
42560803
(
Acceptable).
In
an
8­
day
dietary
study,
MCPB
sodium
was
determined
to
be
practically
non­
toxic
to
mallard
ducklings
with
an
LC
50
>
5000
ppm
ai
(
nominal
concentration).
The
NOEL
was
1250
ppm
ai
(
nominal
concentration).
The
study
is
scientifically
sound
and
generally
followed
guideline
protocols.
Study
design:
Ten
birds
were
assigned
to
each
treatment
level,
including
five
vehicle
control
groups.
Reported
Results:
Mallard
were
exposed
to
five
nominal
concentrations
of
MCPB­
NA:
312,
625,
1250,
2500
and
5000
ppm.
There
were
no
mortalities
at
any
test
level
or
in
control
groups.
There
were
no
clinical
signs
of
toxicity
at
any
test
level.
The
gross
necropsis
revealed
no
abnormal
findings.

72­
1
Freshwater
Fish
Acute
(
Phase
III
3/
07/
06)
    
103
  
147
Rainbow
Trout.
MRID
42532608
(
Acceptable).
In
a
96­
hour
flow­
through
test,
MCPB
sodium
was
determined
to
be
moderately
toxic
to
rainbow
trout
with
an
LC
50
of
4.3
mg
ai/
L.
The
NOEC
was
determined
to
be
1.0
mg
ai/
L.
The
study
is
scientifically
sound
and
meets
guideline
protocols.
Study
design:
Six
concentrations
of
chemical
and
dilution
water
control
were
used,
each
with
two
replicates
of
ten
fish.
Observations
for
mortality
and
sublethal
effects
were
made
daily
throughout
the
exposure
period.
Reported
results:
The
mean
measured
concentrations
of
MCPB
NA
were:
0(
control),
8.0,
4.9,
2.8,
1.8,
1.0,
and
0.60
mg
ai/
L.
Sublethal
effects
(
eg.
Loss
of
equilibrium
and
darkening)
were
observed
in
surviving
fish
at
the
4.9,
2.8,
and
1.8
mg
ai/
L;
there
were
no
other
abnormal
effects
at
any
other
test
levels.
There
was
100%
mortality
at
the
8.0
mg
ai/
L
level
within
48
hours,
70%
mortality
at
4.9
mg
ai/
L
level
by
96
hours,
and
5%
at
2.8
mg
ai/
L
at
96
hours.

Bluegill
Sunfish.
MRID
42532601
(
Acceptable).
In
a
96­
hour
flow­
through
test,
MCPB
sodium
was
determined
to
be
slightly
toxic
to
bluegill
sunfish
with
an
LC
50
of
14
mg
ai/
L.
The
NOEC
was
determined
to
be
8.9
mg
ai/
L.
The
study
is
scientifically
sound
and
meets
guideline
protocols.
Study
design:
Six
concentrations
of
chemical
and
dilution
water
control
were
used,
each
with
two
replicates
of
10
fish.
Observations
for
mortality
and
sublethal
effects
were
made
daily
throughout
the
exposure
period.
Reported
results:
The
mean
measured
concentrations
of
MCPB
NA
were:
0(
control),
29,
16,
8.9,
56.4,
3.5
and
2
mg
ai/
L.
Sublethal
effects
(
eg.
Loss
of
equilibrium
and
darkening)
were
observed
in
surviving
fish
at
the
16
mg
ai/
L
level;
There
were
no
other
sublethal
abnormal
effects
at
any
other
test
levels.
There
was
100%
mortality
at
the
25
mg
ai/
L
within
72
hours,
and
75%
mortality
at
the
16
mg
ai
/
L
level
by
96
hours.
There
was
a
single
mortality
at
the
3.5
mg
ai/
L
level,
but
this
was
not
considered
treatment
related
as
there
were
no
mortalities
at
the
next
highest
level
(
8.9
mgai/
L).

72­
2
Freshwater
Invertebrate
Acute
Daphnia.
MRID
42532602
(
Acceptable).
In
a
48­
hour
flow­
through
test,
MCPB
sodium
was
determined
to
be
slightly
toxic
to
daphnids
with
an
EC
50
of
55
mg
ai/
L
(
95%
confidence
interval
of
49
­
63
mg
ai/
L).
The
NOEC
was
determined
to
be
20
mg
ai/
L.
The
study
is
scientifically
sound
and
meets
guideline
protocols.
Study
design:
Five
concentrations
of
chemical
and
dilution
water
control
were
used,
each
with
two
replicates
of
20
daphnids.
Observations
for
mortality
and
sublethal
effects
were
made
daily
throughout
the
exposure
period.
Reported
results:
The
mean
measured
concentrations
of
MCPB
NA
were:
0(
control),
87,
51,
33,
20,
and
12
mg
ai/
L.
Sublethal
effects
(
e.
g.
lethargy
an
carapace)
were
observed
in
all
surviving
daphnids
at
87
and
51
mg
ai/
L,
and
in
15%
of
the
daphnids
at
33
mg
ai/
L.
There
was
95%
mortality
at
the
87
mg
ai/
L
and
45%
mortality
at
51
mg
ai/
L
by
the
end
of
the
test
period.
81­
1
Acute
Mammalian
Oral
Rat.
MRID
144801
(
Acceptable).
In
an
acute
oral
study,
MCPB
acid
was
determined
to
have
a
low
toxicity
(
Toxicity
Category
III)
to
rats
with
LD
50
'
s
of
4.7
(
3.8
­
6.0)
g/
kg
for
males
and
females
combined.
The
study
is
scientifically
sound
and
meets
guideline
protocols.
(
Phase
III
3/
07/
06)
    
104
  
147
Rat.
MRID
116340
(
Acceptable).
In
an
acute
oral
study,
MCPB
acid
was
determined
to
have
a
low
toxicity
(
Toxicity
Category
III)
to
rats
with
LD
50
'
s
of
1570
(
912
­
2700)
mg/
kg
in
males
and
1700
(
969
­
2981)
mg/
kg
in
females.
The
study
is
scientifically
sound
and
meets
guideline
protocols.

82­
1
Mammalian
Chronic
Dog.
MRID
116345
(
Supplemental).
In
a
90­
day
feeding
study,
MCPB
acid
was
determined
to
produce
reproductive
effects
(
testicular
and
prostate
atrophy;
curtailment
of
spermatogenic
activitiy)
in
dogs
with
a
LOEL
of
1600
ppm
and
the
NOEL
of
480
ppm.
This
study
was
considered
supplemental
because
little
data
was
provided
on
the
concentration
and
stability
of
the
test
material
in
the
diet
and
the
pathological
examination
was
insufficient.

Dog.
MRID
42883603
(
Acceptable).
In
a
13­
week
feeding
study,
MCPB
acid
was
determined
to
produce
sublethal
and
reproductive
effects
(
reduced
testes
weights;
physiological
changes
in
clinical
chemistry)
in
dogs
with
a
LOAEL
of
44
mg/
kg/
day
and
a
NOAEL
of
25
mg/
kg/
day.
The
study
is
scientifically
sound
and
meets
the
guideline
protocols.

Rat.
MRID
42883602
(
Acceptable).
In
a
13­
week
feeding
study,
MCPB
acid
did
not
produce
any
toxicologically
significant
effects
to
rat;
consequently,
the
NOAEL
was
determined
to
be
158
mg/
kg/
day,
the
highest
dose
tested.
The
study
is
scientifically
sound
and
meets
the
guideline
protocols.

83­
3
Mammalian
Developmental
Rat.
MRID
40865402
(
Acceptable).
In
a
developmental
toxicity
study,
MCPB
acid
produced
maternal
toxicity
and
developmental
toxicity
in
Sprague
Dawley
rats
at
100
mg
ai/
kg/
day
(
LOAEL).
The
NOAEL
for
both
was
25
mg
ai/
kg/
day.
The
study
is
scientifically
sound
and
meets
guideline
protocols.

Rabbit.
MRID
40865401
(
Acceptable).
In
a
developmental
toxicity
study,
MCPB
acid
produced
maternal
toxicity
(
death)
at
20
mg
ai/
kg/
day
(
LOAEL)
in
New
Zealand
white
rabbits.
The
NOAEL
for
maternal
toxicity
was
5
mg
ai/
kg/
day
the
NOAEL
for
developmental
toxicity
was
20
mg
ai/
kg/
day.
The
study
is
scientifically
sound
and
meets
guideline
protocols.

83­
4
Mammalian
Reproduction
­
MCPA
Rat.
MRID
40041701
(
Acceptable).
In
a
2­
generation
reproduction
study,
MCPA
acid
produced
maternal
and
offspring
toxicity
at
22.5
mg
ai/
kg/
day
(
LOAEL)
in
Crl:
CD
(
SD)
rats.
The
NOAEL
for
maternal
and
offspring
toxicity
was
7.5
mg
ai/
kg/
day.
There
were
no
treatment­
related
developmental
effects
to
the
fetuses.
The
study
is
scientifically
sound
and
meets
guideline
protocols.
(
Phase
III
3/
07/
06)
    
105
  
147
122­
1(
b)
Vegetative
Vigor
­
Tier
I
Corn
and
Oats.
MRID
42560804
(
Acceptable).
In
a
Tier
I
vegetative
vigor
test,
corn
and
oats
had
<
25%
detrimental
effects.
The
NOECs
for
the
corn
and
oats
were
1.5
lb
ai/
acre
and
1.3
lb
ai/
acre,
respectively.
The
study
is
scientifically
sound
and
meets
the
guideline
protocols.

122­
2
Aquatic
Plant
Algae
Blue­
green
algae.
MRID
42532603
(
Acceptable).
In
a
Tier
I
toxicity
test
with
blue­
green
algae,
the
EC
50
for
cell
density
was
>
2.1
mg
ai/
L.
Tier
II
testing
was
not
required
for
this
species
because
the
NOEC
exceeded
the
maximum
label
rate
of
1.5
lb
ai/
acre.
The
study
is
scientifically
sound
and
meets
the
guideline
protocols.

Green
algae.
MRID
42532605
(
Acceptable).
In
a
Tier
I
toxicity
test
with
green
algae,
the
120­
hour
EC
50
for
cell
density
was
0.42
mg
ai/
L.
The
study
is
scientifically
sound
and
meets
the
guideline
protocols.

Marine
diatom.
MRID
42532606
(
Acceptable).
In
a
Tier
I
and
II
toxicity
test
with
the
marine
diatom,
the
120­
hour
EC
50
for
cell
density
was
1.5
mg
ai/
L.
The
study
is
scientifically
sound
and
meets
the
guideline
protocols.

Diatom.
MRID
42532609
(
Acceptable).
In
a
Tier
I
and
II
toxicity
test
with
the
diatom,
the
120­
hour
EC
50
for
cell
density
was
0.71
mg
ai/
L
with
a
95%
confidence
limit
of
(
0.11
­
4.6),
The
NOEC
was
.048mg
ai/
L.
The
study
is
scientifically
sound
and
meets
the
guideline
protocols
123­
1(
a)
Seedling
Emergence
­
Tier
II
Monocots
(
5
species)
and
Dicots
(
5
species).
MRID
42560804
(
Acceptable).
In
a
Tier
II
seedling
emergence
study,
mortality
and
morphological
abnormalities
were
observed
in
all
species
tested
(
cabbage,
corn,
cucumber,
lettuce,
oats,
onion,
ryegrass,
radish,
soybean,
and
tomato)
with
shoot
length
being
the
most
sensitive
parameter
tested
and
cabbage
the
most
sensitive
species
(
EC
25
0.017
lb
ai/
acre,
NOEC
0.012
lb
ai/
acre).
The
study
is
scientifically
sound
and
meets
guideline
protocols.

123­
1(
b)
Vegetative
Vigor
­
Tier
II
Monocots
(
3
species)
and
Dicots
(
5
species).
MRID
42560804
(
Acceptable).
In
a
Tier
II
vegetative
vigor
study,
mortality
and
morphological
abnormalities
were
observed
in
all
species
tested
(
cabbage,
cucumber,
lettuce,
onion,
ryegrass,
radish,
soybean,
and
tomato)
with
shoot
weight
being
the
most
sensitive
parameter
tested
and
tomato
the
most
sensitive
species
(
EC
25
0.0017
lb
ai/
L).
There
is
uncertainty
in
the
vegetative
vigor
EC
25
values
for
dicots,
because
they
were
extrapolated
below
the
lowest
dose
tested
in
the
study.
Furthermore,
the
NOEC
values
reported
in
the
original
study
were
reported
as
being
higher
than
the
EC
25
values.
Further
extrapolation
of
the
data
needs
to
be
done
to
derive
EC
05
values
from
the
dose
response
curves
for
the
vegetative
vigor
study.
The
study
is
scientifically
sound
and
meets
guideline
protocols.
(
Phase
III
3/
07/
06)
    
106
  
147
123­
2
Aquatic
Plant
Acute
Duckweed.
MRID
42532604
(
Acceptable).
In
a
14­
day
toxicity
test
with
duckweed,
the
EC
50
for
frond
production
was
0.23
mg
ai/
L
and
the
EC
50
for
frond
biomass
was
1.7
mg
ai/
L.
The
study
is
scientifically
sound
and
meets
guideline
protocols.

141­
1
Acute
Honey
Bee
Contact
Honey
Bee.
MRID
42532607
(
Acceptable).
In
a
48­
hour
acute
contact
study
with
the
honey
bee,
the
LD
50
was
>
25
µ
g/
bee
classifies
MCPB
as
relatively
non­
toxic
to
honey
bees.
.
The
study
is
scientifically
sound
and
meets
guideline
protocols.
Design
and
Dose:
Three
replicates
of
25
bees
each
were
used
for
each
treatment
and
the
controls.
One
treatment
level
(
25
µ
g/
bee)
was
used.
Reported
results:
There
was
15%
mortality
(
11)
bees
in
the
treated
bees
after
48
hours.
No
other
significant
effects
were
reported.
APPENDIX
F:
Data
Requirements
(
Phase
III
3/
07/
06)
    
108
  
147
Appendix
F:
Data
Requirement
Tables
for
MCPB
TABLE
of
Environmental
Fate
Data
Requirements
Guideline
#
Data
Requirement
MRID
#
Study
Classification
Is
more
data
needed?

161­
1
Hydrolysis
4257430
1
Acceptable
no
161­
2
Photodegradation
in
Water
4257430
2
Acceptable
no
161­
3
Photodegradation
on
Soil
4382990
1
Invalid
no
161­
4
Photodegradation
in
Air
N/
A
no
162­
1
Aerobic
Soil
Metabolism
4324760
1
Acceptable
no
162­
2
Anaerobic
Soil
Metabolism
43015501
Acceptable
no
162­
3
Anaerobic
Aquatic
Metabolism
No
study
submitte
d
no
162­
4
Aerobic
Aquatic
Metabolism
No
study
submitte
d
(
not
at
this
time)

163­
1
Leaching­
Adsorption/
Desorption
4269370
1
4346640
1
Acceptable
no
163­
2
Laboratory
Volatility
N/
A
163­
3
Field
Volatility
N/
A
164­
1
Terrestrial
Field
Dissipation
No
study
submitte
d
yes
164­
2
Aquatic
Field
Dissipation
N/
A
164­
3
Forestry
Dissipation
N/
A
165­
4
Accumulation
in
Fish
N/
A
165­
5
Accumulation­
aquatic
non­
target
N/
A
166­
1
Ground
Water­
small
prospective
N/
A
166­
2
Groundwater
­
small
retrospective
N/
A
201­
1
Droplet
Size
Spectrum
N/
A
202­
1
Drift
Field
Evaluation
N/
A
(
Phase
III
3/
07/
06)
    
109
  
147
TABLE
of
Ecological
Toxicity
Data
Requirements
Guideline
#
Data
Requirement
MRID
#
Classification
Is
more
data
needed?

71­
1
Avian
acute
oral
LD50
(
bobwhite
quail)
42560801
Acceptable
No
71­
2
Avian
acute
dietary
LC50
(
bobwhite
quail)
(
mallard
duck)
42560802
42560803
Acceptable
Acceptable
No
71­
4
Avian
reproduction
(
bobwhite
quail)
(
mallard
duck)
43505201
(
MCPA)
Acceptable
No
72­
1
Freshwater
fish
acute
LC500
(
rainbow
trout)
(
bluegill
sunfish)
42532608
42532601
Acceptable
Acceptable
No
72­
2
Freshwater
invertebrate
acute
EC50
(
daphnia)
42532602
Acceptable
No
72­
3a
Estuarine/
marine
fish
acute
LC50
(
sheepshead
minnow)
N/
A
Yes
72­
3b
Estuarine/
marine
invertebrate
acute
EC50
(
eastern
oyster)
N/
A
Yes
72­
4a
Estuarine
marine
fish
early
life
stage
N/
A
Reserved
72­
4a
Freshwater
fish
early
life
stage
(
fathead
minnow)
N/
A
Yes
72­
4b
Freshwater
invertebrate
life
cycle
(
daphnia)
N/
A
Yes
72­
4d
Estuarine/
marine
life
cycle
(
mysid)
N/
A
Reserved
72­
5
Freshwater
fish
full
life
cycle
N/
A
Reserved
72­
7
Aquatic
Field
Study
N/
A
No
81­
1
Acute
mammalian
oral
LD50
(
rat)
144801
116340
Acceptable
No
82­
1(
a)
82­
1(
b)
Mammalian
chronic
(
dog)
(
rat)
1.16345e+
11
Acceptableminimum
Acceptableminimum
No
83­
1(
a)
83­
1(
b)
Mammalian
Chronic
N/
A
Reserved
83­
3
Mammalian
Developmental
(
rat)
(
rabbit)
408654
Acceptable
Acceptable
No
83­
4
MCPB
Mammalian
Reproduction
N/
A
Yes
83­
4
MPCA
Mammalian
Reproduction
40041701
Acceptable
No
123­
1(
a)
Seedling
Emergence
­
Tier
II
42560804
Acceptable
No
122­
1(
b)
Vegetative
Vigor
­
Tier
I
42560804
Acceptable
No
(
Phase
III
3/
07/
06)
    
110
  
147
123­
1(
b)
Vegetative
Vigor
­
Tier
II
42560804
Acceptable
No
122­
2
Aquatic
plant
algae
(
green
algae)
(
blue­
green
algae)
(
diatom)
(
marine
diatom)
42532605
42532603
42532609
42532606
Acceptable
Acceptable
Acceptable
Acceptable
No
123­
2
Aquatic
plant
acute
EC50
(
duckweed)
42532604
Acceptable
No
141­
1
Acute
honey
bee
contact
LD50
42532607
Acceptable
No
141­
2
Honey
Bee
Residue
on
Foliage
N/
A
Yes
141­
5
Honey
Bee
Field
Testing
for
Pollinator
N/
A
Yes
APPENDIX
G:
Environmental
Fate
Bibliography
(
Phase
III
3/
07/
06)
    
112
  
147
Environmental
Fate
Bibliography
Das,
Y.
T.
1992.
Hydrolysis
of
[
14C]
MCPB
in
aqueous
solutions
buffered
at
pH
5,
7
and
9.
Unpublished
study
performed
by
Innovative
Scientific
Services,
Inc.,
Piscataway,
NJ
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Lyon
Cedex,
France.
ISSI
Study
Number
92010;
Rhone­
Poulenc
Study
Number
92­
06.
September
23,
1992.
MRID
42574301
Das,
Y.
T.
1992.
Photodegradation
of
[
14C]
MCPB
in
aqueous
solutions
buffered
at
pH
5,
7
and
9
under
artificial
sunlight.
Unpublished
study
performed
by
Innovative
Scientific
Services,
Inc.,
Piscataway,
NJ
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Lyon
Cedex,
France.
ISSI
Study
Number
92011;
Rhone­
Poulenc
Study
Number
92­
07.
September
23,
1992.
MRID
42574302
Robson,
M.
M.
1993.
Determination
of
adsorption/
desorption
characteristics
of
4­(
2­
methyl,
4­
chlorophenoxy)
butyric
acid
(
MCPB)
in
soil.
Unpublished
study
performed
by
Hazleton
UK,
North
Yorkshire,
England.
HUK
Study
No.
68/
127.
Study
sponsored
by
Rhône­
Poulenc
Agriculture,
Essex,
England.
February
10,
1993.
MRID
42693701
Goodyear,
A.
1993.
(
14C)­
MCPB:
anaerobic
soil
metabolism.
Unpublished
study
performed
by
Hazleton
UK,
North
Yorkshire,
England,
and
sponsored
by
MCPB
Task
Force,
c/
o
Rhône­
Poulenc
Agricultural
Limited,
Essex,
England.
Laboratory
Study
No.
68/
131
and
Report
No.
68/
131­
1015.
MRID
43015501
Howard,
P.
H.
and
W.
M.
Meylan.
1997.
Handbook
of
Physical
Properties
of
Organic
Chemicals.
Lewis
Publishers,
New
York.
p.
121.

John,
A.,
et
al.
1994.
MCPB:
aerobic
soil
metabolism.
Unpublished
study
performed
and
sponsored
by
MCPB
Task
Force,
c/
o
Rhône­
Poulenc
Agricultural
Limited,
Essex,
England.
Laboratory
Project
and
Study
ID:
P
93/
194.
MRID
43247601
John,
A.
E.,
M.
K.
Jones
and
P.
Lowden.
1994.
MCPB:
Fresh
and
aged
leaching
study
in
five
soils.
Laboratory
Project
ID.
P
92/
333.
Unpublished
study
performed
and
submitted
by
Rhône­
Poulenc
Agriculture
Limited,
Essex,
England.
Laboratory
Project
ID:
P
92/
333.
MRID
43466401
Ferreira,
E.
M.,
A.
E.
John,
P.
Lowden,
and
D.
J.
Austin.
1992.
MCPB
soil
photolysis
study.
Laboratory
Project
ID:
P92/
126.
Unpublished
study
performed
and
submitted
by
Rhône­
Poulenc
Agriculture
Limited,
Ongar,
Essex,
England.
MRID
43829901
Podall,
H.
2002.
CBI
Product
Chemistry
Review.
March
8,
2002.

Tomlin,
C.
D.
S.,
ed.
1997.
The
Pesticide
Manual
­
#
65
MCPB
Sodium
Salt.
British
Crop
Protection
Council,
11th
ed,
Farnham,
Surrey,
UK.
p.
254.

WSSA
(
Weed
Science
Society
of
America).
1994.
Herbicide
Handbook.
Ahrens
W.
H.,
Ed.,
Champaign,
IL.
p.
352.
APPENDIX
H:
Ecotoxicity
Bibliography
(
Phase
III
3/
07/
06)
    
114
  
147
Ecotoxicity
Bibliography
Bettencourt,
M.
J.
1992.
MCPB
Sodium
­
Acute
toxicity
to
rainbow
trout
(
Oncorhynchus
mykiss)
under
flow­
through
conditions.
Unpublished
study
performed
by
Springborn
Laboratories,
Inc.,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
SLI
Report
Number
92­
7­
4228.
MRID
42532608
Bettencourt,
M.
J.
1992.
MCPB
Sodium
­
Acute
toxicity
to
bluegill
sunfish
(
Lepomis
macrochirus)
under
flow­
through
conditions.
Unpublished
study
performed
by
Springborn
Laboratories,
Inc.,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
SLI
Report
Number
92­
8­
4263.
MRID
42532601
Christensen,
K.
P.
1992.
MCPB
Sodium
­
Determination
of
effects
on
seed
germination,
seedling
emergence
and
vegetative
vigor
of
ten
plant
species.
Unpublished
study
performed
by
Springborn
Laboratories,
Inc.,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Number
HWA
656­
172.
July
14,
1993.
MRID
42560804
Corley,
J.
and
D.
L.
Kunkel.
1999.
MCPB:
Magnitude
of
the
residue
on
pea
(
reregistration).
Unpublished
study
performed
by
Environmental
Toxicology
Laboratory,
University
of
California,
Davis,
CA
and
sponsored
by
Rutgers
University,
North
Brunswick,
NJ.
Study
Number
05470.94­
CAR23.
MRID
44754101
Dalgard,
D.
W.
1993.
13­
Week
dietary
toxicity
study
with
MCPB
in
dogs.
Unpublished
study
performed
by
Hazleton
Washington,
Inc.,
Vienna,
VA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
SLI
Report
Number
92­
8­
4263.
MRID
42883603
Dexter,
A.
G.,
J.
L.
Gunsolus,
and
W.
S.
Curran.
1994.
Herbicide
Mode
of
Action
and
Sugarbeet
Injury
Symptoms.
North
Dakota
State
University
of
Agriculture
and
Applied
Science,
Fargo,
ND.

Ferrell,
J.
A.,
G.
E.
MacDonald,
B.
J.
Brecke,
A.
C.
Bennett,
and
J.
Tredaway
Ducar.
2005.
Florida s
Organo­
Auxin
Herbicide
Rule
­
2005.
University
of
Florida,
Institute
of
Food
and
Agricultural
Sciences,
Gainesville,
FL.

Heimann,
M.
F.
and
R.
C.
Newman.
1997.
Plant
injury
due
to
turfgrass
broadleaf
weed
herbicides.
University
of
Wisconsin
­
Cooperative
Extension,
Madison,
WI.

Hoberg,
J.
R.
1992.
MCPB
Sodium
­
Toxicity
to
the
freshwater
blue­
green
alga,
Anabaena
flos­
aquae.
Unpublished
study
performed
by
Springborn
Laboratories,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Number
10566.0392.6230.420.
MRID
42532603
Hoberg,
J.
R.
1992.
MCPB
Sodium
­
Toxicity
to
the
green
alga,
Selenastrum
capricornutum.
Unpublished
study
performed
by
Springborn
Laboratories,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Report
Number
92­
8­
4361.
MRID
42532605
(
Phase
III
3/
07/
06)
    
115
  
147
Hoberg,
J.
R.
1992.
MCPB
Sodium
­
Toxicity
to
the
freshwater
diatom,
Navicula
pelliculosa
Unpublished
study
performed
by
Springborn
Laboratories,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Number
10566.0392.6230.440.
MRID
42532609
Hoberg,
J.
R.
1992.
MCPB
Sodium
­
Toxicity
to
the
marine
diatom,
Skeletonema
costatum.
Unpublished
study
performed
by
Springborn
Laboratories,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Report
Number
92­
8­
4372.
MRID
42532606
Hoberg,
J.
R.
1992.
MCPB
Sodium
­
Toxicity
to
the
duckweed,
Lemna
gibba.
Unpublished
study
performed
by
Springborn
Laboratories,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Report
Number
92­
8­
4368.
MRID
42532604
Holsing,
G.
1969.
Acute
Oral
­
Rats
­
MCPB
Technical.
Unpublished
study
performed
by
TRW,
Inc.
and
sponsored
by
Rhodia,
Inc.
Project
Report
Number
517­
102.
MRID
116340
Kynoch,
S.
1985.
Acute
oral
toxicity
to
rats
of
MCPB
Technical
Acid.
Unpublished
study
performed
by
Huntingdon
Research
Center.
MRID
144801
Lingenfelter,
D.
D.
and
N.
L.
Hartwig.
2003.
Introduction
to
Weeds
and
Herbicides.
Penn
State
College
of
Agricultural
Sciences
­
Agricultural
Research
and
Cooperative
Extension.
Pp.
1
­
20.

MacKenzie,
K.
1986.
Two­
generation
reproduction
study
with
MCPA
in
rats.
Unpublished
study
performed
by
Hazleton
Laboratories
America,
Inc.,
Madison,
WI.
Laboratory
Study
Number
6148­
100.
MRID
40041701
Maggi,
V.
L.
1992.
Acute
contact
toxicity
of
MCPB
sodium
salt
to
honey
bees
(
Apis
mellifera).
Unpublished
study
performed
by
California
Agricultural
Research,
Inc.,
Kerman,
CA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Laboratory
Study
Number
CAR
169­
92.
MRID
42532607
Pedersen,
C.
A.
and
B.
R.
Helsten.
1992.
MCPB
Sodium:
14­
Day
acute
oral
LD50
study
in
bobwhite
quail.
Unpublished
study
performed
by
BioLife
Associates,
Ltd.,
Neillsville,
WI
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Number
BLAL
108­
016­
03.
MRID
42560801
Pedersen,
C.
A.
and
B.
R.
Helsten.
1992.
MCPB
Sodium:
8­
Day
acute
dietary
study
in
bobwhite
quail.
Unpublished
study
performed
by
BioLife
Associates,
Ltd.,
Neillsville,
WI
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Number
BLAL
108­
014­
01.
MRID
42560802
Pedersen,
C.
A.
and
B.
R.
Helsten.
1992.
MCPB
Sodium:
8­
Day
acute
dietary
study
in
mallard
ducklings.
Unpublished
study
performed
by
BioLife
Associates,
Ltd.,
Neillsville,
WI
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Number
BLAL
108­
015­
04.
MRID
42560803
(
Phase
III
3/
07/
06)
    
116
  
147
Putt,
A.
E.
1992.
MCPB
Sodium
­
Acute
toxicity
to
daphnids
(
Daphnia
magna)
under
flow­
through
conditions.
Unpublished
study
performed
by
Springborn
Laboratories,
Wareham,
MA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Report
Number
92­
7­
4351.
MRID
42532602
Trutter,
J.
A.
1993.
13­
Week
dietary
toxicity
study
with
MCPB
in
rats.
Unpublished
study
performed
by
Hazleton
Washington,
Inc.,
Vienna,
VA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Number
HWA
656­
174.
MRID
42883602
Tyl,
R.
W.
1988.
Developmental
toxicity
evaluation
of
MCPB
administered
by
gavage
to
CD
(
Sprague
Dawley)
Rats.
Unpublished
study
performed
by
Bushy
Run
Research
Center,
Export,
PA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Report
Number
51­
532.
MRID
40865402
Tyl,
R.
W.
and
T.
L.
Neeper­
Bradley
1988.
Developmental
toxicity
evaluation
of
MCPB
administered
by
gavage
to
New
Zealand
White
Rabbits.
Unpublished
study
performed
by
Bushy
Run
Research
Center,
Export,
PA
and
sponsored
by
Rhône­
Poulenc
Agrochemie,
Research
Triangle
Park,
NC.
Study
Report
Number
51­
547.
MRID
40865401
(
Phase
III
3/
07/
06)
    
117
  
147
APPENDIX
I:
Locates
Endangered
Species
(
Phase
III
3/
07/
06)
    
118
  
147
Unique
Taxa
Count
by
State
for
Selected
Crops
Reporting
for
>
1
Acres
Cowpeas
and
southern
peas,
dry
(
53),
Peas,
dry
edible
(
55),
Cowpeas
and
southern
peas,
green
(
78),
Peas,
green,
excluding
cowpeas
(
81),
Peas,
all
(
312)

Cowpeas
and
southern
peas,
dry
Bird
Fish
MammalAmphibianCrustacean
Reptile
Arachnids
InsectsPlant
Snails
Clam
Affected
Counties:
27
17
14
13
12
13
12
14
1
2
Affected
States:
5
3
4
5
2
2
0
2
3
1
2
Affected
Species:
15
11
10
4
5
4
5
33
1
6
Cowpeas
and
southern
peas,
green
Bird
Fish
MammalAmphibianCrustacean
Reptile
Arachnids
InsectsPlant
Snails
Clam
Affected
Counties:
162
60
52
18
2
61
6
65
4
37
Affected
States:
12
9
12
4
2
9
0
3
12
2
10
Affected
Species:
16
17
8
4
2
12
2
56
4
31
Peas,
all
Bird
Fish
MammalAmphibianCrustacean
Reptile
Arachnids
InsectsPlant
Snails
Clam
Affected
Counties:
408
152
188
37
22
91
52
204
8
60
Affected
States:
39
22
36
5
5
12
1
14
37
5
20
Affected
Species:
48
39
38
10
11
21
1
27
350
10
37
Peas,
dry
edible
Bird
Fish
MammalAmphibianCrustacean
Reptile
Arachnids
InsectsPlant
Snails
Clam
Affected
Counties:
64
28
13
3
9
2
Affected
States:
7
6
6
2
0
0
0
0
4
1
0
Affected
Species:
5
6
4
2
4
4
Peas,
green,
excluding
cowpeas
Bird
Fish
MammalAmphibianCrustacean
Reptile
Arachnids
InsectsPlant
Snails
Clam
Thursday,
June
09,
2005
Page
1
of
20
(
Phase
III
3/
07/
06)
    
119
  
147
Peas,
green,
excluding
cowpeas
Bird
Fish
MammalAmphibianCrustacean
Reptile
Arachnids
InsectsPlant
Snails
Clam
Affected
Counties:
196
65
123
11
6
29
33
137
2
32
Affected
States:
35
18
29
4
2
9
0
10
32
2
17
Affected
Species:
21
19
23
5
4
13
19
130
3
24
Thursday,
June
09,
2005
Page
2
of
20
(
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III
3/
07/
06)
    
120
  
147
Grand
Summary
Bird
Fish
MammalAmphibianCrustacean
Reptile
Arachnids
Insects
PlantSnails
Clam
Total
Counties:
408
152
188
37
22
91
1
52
204
8
60
Total
States:
39
22
36
5
5
12
1
14
37
5
20
Unique
Species
Totals:
48
39
38
10
11
21
1
27
350
10
37
Species
Affected:

FROG,
MOUNTAIN
YELLOW­
LEGGED
Rana
muscosa
Amphibian
TREEFROG,
PINE
BARRENS
Hyla
andersonii
Amphibian
TOAD,
HOUSTON
Bufo
houstonensis
Amphibian
TOAD,
ARROYO
SOUTHWESTERN
Bufo
californicus
(=
microscaphus)
Amphibian
FROG,
CALIFORNIA
RED­
LEGGED
Rana
aurora
draytonii
Amphibian
SALAMANDER,
CALIFORNIA
TIGER
Ambystoma
californiense
Amphibian
SALAMANDER,
DESERT
SLENDER
Batrachoseps
aridus
Amphibian
SALAMANDER,
FLATWOODS
Ambystoma
cingulatum
Amphibian
SALAMANDER,
SANTA
CRUZ
Ambystoma
macrodactylum
croceum
Amphibian
LONG­
TOED
SALAMANDER,
RED
HILLS
Phaeognathus
hubrichti
Amphibian
SPIDER,
KAUAI
CAVE
WOLF
Adelocosa
anops
Arachnid
TERN,
CALIFORNIA
LEAST
Sterna
antillarum
browni
Bird
SPARROW,
FLORIDA
GRASSHOPPER
Ammodramus
savannarum
floridanus
Bird
SHEARWATER,
NEWELL'S
Puffinus
auricularis
newelli
Bird
TOWNSEND'S
CAHOW
Pterodroma
cahow
Bird
THRUSH,
LARGE
KAUAI
Myadestes
myadestinus
Bird
CURLEW,
ESKIMO
Numenius
borealis
Bird
PLOVER,
PIPING
Charadrius
melodus
Bird
PLOVER,
WESTERN
SNOWY
Charadrius
alexandrinus
nivosus
Bird
CROW,
HAWAIIAN
('
ALALA)
Corvus
hawaiiensis
Bird
CREEPER,
HAWAII
Oreomystis
mana
Bird
CRANE,
WHOOPING
Grus
americana
Bird
CONDOR,
CALIFORNIA
Gymnogyps
californianus
Bird
TERN,
INTERIOR
(
POPULATION)
Sterna
antillarum
Bird
COOT,
HAWAIIAN
(=
ALAE
KEO
Fulica
americana
alai
Bird
HAWK,
HAWAIIAN
(
IO)
Buteo
solitarius
Bird
CARACARA,
AUDUBON'S
CRESTED
Polyborus
plancus
audubonii
Bird
THRUSH,
SMALL
KAUAI
(
PUAIOHI)
Myadestes
palmeri
Bird
Thursday,
June
09,
2005
Page
3
of
20
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3/
07/
06)
    
121
  
147
RAIL,
CALIFORNIA
CLAPPER
Rallus
longirostris
obsoletus
Bird
RAIL,
LIGHT­
FOOTED
CLAPPER
Rallus
longirostris
levipes
Bird
RAIL,
YUMA
CLAPPER
Rallus
longirostris
yumanensis
Bird
GNATCATCHER,
COASTAL
Polioptila
californica
californica
Bird
CALIFORNIA
STORK,
WOOD
Mycteria
americana
Bird
STILT,
HAWAIIAN
(=
AE'O)
Himantopus
mexicanus
knudseni
Bird
GOOSE,
HAWAIIAN
(
NENE)
Branta
(=
Nesochen)
sandvicensis
Bird
TERN,
ROSEATE
Sterna
dougallii
dougallii
Bird
KITE,
EVERGLADE
SNAIL
Rostrhamus
sociabilis
plumbeus
Bird
'
AKIA
POLA'AU
(
HEMIGNATHUS
Hemignathus
munroi
Bird
MUNROI)

OWL,
NORTHERN
SPOTTED
Strix
occidentalis
caurina
Bird
PALILA
Loxioides
bailleui
Bird
DUCK,
HAWAIIAN
(
KOLOA)
Anas
wyvilliana
Bird
VIREO,
BLACK­
CAPPED
Vireo
atricapilla
Bird
VIREO,
LEAST
BELL'S
Vireo
bellii
pusillus
Bird
PELICAN,
BROWN
Pelecanus
occidentalis
Bird
'
O'U
(
HONEYCREEPER)
Psittirostra
psittacea
Bird
PETREL,
HAWAIIAN
DARK­
RUMPED
Pterodroma
phaeopygia
sandwichensis
Bird
OWL,
MEXICAN
SPOTTED
Strix
occidentalis
lucida
Bird
'
AKEPA,
HAWAII
Loxops
coccineus
coccineus
Bird
'
AKIA
LOA,
KAUAI
(
HEMIGNATHUS
Hemignathus
procerus
Bird
PROCERUS)

NUKU
PU'U
Hemignathus
lucidus
Bird
FALCON,
NORTHERN
APLOMADO
Falco
femoralis
septentrionalis
Bird
WOODPECKER,
RED­
COCKADED
Picoides
borealis
Bird
JAY,
FLORIDA
SCRUB
Aphelocoma
coerulescens
Bird
'
O'O,
KAUAI
(='
A'A)
Moho
braccatus
Bird
WARBLER
(
WOOD),
Dendroica
chrysoparia
Bird
GOLDEN­
CHEEKED
EAGLE,
BALD
Haliaeetus
leucocephalus
Bird
MURRELET,
MARBLED
Brachyramphus
marmoratus
marmoratus
Bird
FLYCATCHER,
SOUTHWESTERN
Empidonax
traillii
extimus
Bird
WILLOW
MOORHEN,
HAWAIIAN
COMMON
Gallinula
chloropus
sandvicensis
Bird
MUSSEL,
DWARF
WEDGE
Alasmidonta
heterodon
Clam
MUSSEL,
SCALESHELL
Leptodea
leptodon
Clam
RIFFLESHELL,
NORTHERN
Epioblasma
torulosa
rangiana
Clam
STIRRUP
SHELL
Quadrula
stapes
Clam
COMBSHELL,
SOUTHERN
Epioblasma
penita
Clam
(=
PENITENT
MUSSEL)

Thursday,
June
09,
2005
Page
4
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20
(
Phase
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147
MOCCASINSHELL,
ALABAMA
Medionidus
acutissimus
Clam
FANSHELL
Cyprogenia
stegaria
Clam
FATMUCKET,
ARKANSAS
Lampsilis
powelli
Clam
MUSSEL,
WINGED
MAPLELEAF
Quadrula
fragosa
Clam
KIDNEYSHELL,
TRIANGULAR
Ptychobranchus
greeni
Clam
SLABSHELL,
CHIPOLA
Elliptio
chipolaensis
Clam
SPINYMUSSEL,
TAR
RIVER
Elliptio
steinstansana
Clam
ROCK­
POCKETBOOK,
OUACHITA
Arkansia
wheeleri
Clam
(=
WHEELER'S
PM)

PIGTOE,
CUMBERLAND
Pleurobema
gibberum
Clam
(=
CUMBERLAND
PIGTOE
MUSSEL
PIGTOE,
DARK
Pleurobema
furvum
Clam
PIGTOE,
FINE­
RAYED
Fusconaia
cuneolus
Clam
PIGTOE,
FLAT
(=
MARSHALL'S
Pleurobema
marshalli
Clam
MUSSEL)

PIGTOE,
HEAVY
(=
JUDGE
TAIT'S
Pleurobema
taitianum
Clam
MUSSEL)

PIGTOE,
OVAL
Pleurobema
pyriforme
Clam
PIGTOE,
ROUGH
Pleurobema
plenum
Clam
CLUBSHELL,
OVATE
Pleurobema
perovatum
Clam
HEELSPLITTER,
INFLATED
Potamilus
inflatus
Clam
CLUBSHELL
Pleurobema
clava
Clam
BANKCLIMBER,
PURPLE
Elliptoideus
sloatianus
Clam
PIGTOE,
SOUTHERN
Pleurobema
georgianum
Clam
THREERIDGE,
FAT
Amblema
neislerii
Clam
PEARLYMUSSEL,
PINK
MUCKET
Lampsilis
abrupta
Clam
PEARLYMUSSEL,
ORANGE­
FOOTED
Plethobasus
cooperianus
Clam
PEARLYMUSSEL,
HIGGINS'
EYE
Lampsilis
higginsii
Clam
POCKETBOOK,
FAT
Potamilus
capax
Clam
POCKETBOOK,
FINE­
LINED
Lampsilis
altilis
Clam
POCKETBOOK,
SHINY­
RAYED
Lampsilis
subangulata
Clam
MUCKET,
ORANGE­
NACRE
Lampsilis
perovalis
Clam
MOCCASINSHELL,
GULF
Medionidus
penicillatus
Clam
CLUBSHELL,
SOUTHERN
Pleurobema
decisum
Clam
PIGTOE,
SHINY
Fusconaia
cor
Clam
HEELSPLITTER,
CAROLINA
Lasmigona
decorata
Clam
SHRIMP,
ALABAMA
CAVE
Palaemonias
alabamae
Crustacean
SHRIMP,
VERNAL
POOL
TADPOLE
Lepidurus
packardi
Crustacean
SHRIMP,
VERNAL
POOL
FAIRY
Branchinecta
lynchi
Crustacean
SHRIMP,
SQUIRREL
CHIMNEY
CAVE
Palaemonetes
cummingi
Crustacean
SHRIMP,
SAN
DIEGO
FAIRY
Branchinecta
sandiegonensis
Crustacean
Thursday,
June
09,
2005
Page
5
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20
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06)
    
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147
SHRIMP,
RIVERSIDE
FAIRY
Streptocephalus
woottoni
Crustacean
SHRIMP,
CONSERVANCY
FAIRY
Branchinecta
conservatio
Crustacean
SHRIMP,
CALIFORNIA
FRESHWATER
Syncaris
pacifica
Crustacean
SHRIMP,
LONGHORN
FAIRY
Branchinecta
longiantenna
Crustacean
ISOPOD,
MADISON
CAVE
Antrolana
lira
Crustacean
AMPHIPOD,
KAUAI
CAVE
Spelaeorchestia
koloana
Crustacean
SALMON,
CHUM
(
HOOD
CANAL
Oncorhynchus
(=
Salmo)
keta
Fish
SUMMER
POPULATION)

SALMON,
ATLANTIC
Salmo
salar
Fish
SALMON,
CHINOOK
(
CALIFORNIA
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
COASTAL
ESU)

SALMON,
CHINOOK
(
CENTRAL
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
VALLEY
SPRING
RUN)

SALMON,
CHINOOK
(
LOWER
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
COLUMBIA
RIVER)

SALMON,
CHINOOK
(
PUGET
SOUND)
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
SALMON,
CHINOOK
(
SACRAMENTO
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
RIVER
WINTER
RUN)

SALMON,
CHINOOK
(
SNAKE
RIVER
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
FALL
RUN)

SALMON,
CHINOOK
(
SNAKE
RIVER
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
SPRING/
SUMMER)

SALMON,
CHINOOK
(
UPPER
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
COLUMBIA
RIVER
SPRING)

STEELHEAD,
UPPER
COLUMBIA
Oncorhynchus
(=
Salmo)
mykiss
Fish
RIVER
POPULATION
SALMON,
CHUM
(
COLUMBIA
RIVER
Oncorhynchus
(=
Salmo)
keta
Fish
POPULATION)

CHUB,
MOHAVE
TUI
Gila
bicolor
mohavensis
Fish
SALMON,
COHO
(
CENTRAL
Oncorhynchus
(=
Salmo)
kisutch
Fish
CALIFORNIA
COAST
POP)

SALMON,
COHO
(
OREGON
COAST
Oncorhynchus
(=
Salmo)
kisutch
Fish
POPULATION)

SALMON,
COHO
(
SOUTHERN
Oncorhynchus
(=
Salmo)
kisutch
Fish
OR/
NORTHERN
CA
COAST)

SALMON,
SOCKEYE
(
SNAKE
RIVER
Oncorhynchus
(=
Salmo)
nerka
Fish
POPULATION)

STEELHEAD,
SOUTHERN
Oncorhynchus
(=
Salmo)
mykiss
Fish
CALIFORNIA
POPULATION
SAWFISH,
SMALLTOOTH
Pristis
pectinata
Fish
STEELHEAD,
SOUTH­
CENTRAL
Oncorhynchus
(=
Salmo)
mykiss
Fish
CALIFORNIA
POP
SALMON,
CHINOOK
(
UPPER
Oncorhynchus
(=
Salmo)
tshawytscha
Fish
WILLAMETTE
RIVER)

TROUT,
BULL
Salvelinus
confluentus
Fish
DARTER,
SNAIL
Percina
tanasi
Fish
Thursday,
June
09,
2005
Page
6
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147
DARTER,
SLACKWATER
Etheostoma
boschungi
Fish
DARTER,
OKALOOSA
Etheostoma
okaloosae
Fish
DARTER,
LEOPARD
Percina
pantherina
Fish
DARTER,
ETOWAH
Etheostoma
etowahae
Fish
DARTER,
CHEROKEE
Etheostoma
scotti
Fish
DARTER,
BAYOU
Etheostoma
rubrum
Fish
TROUT,
PAIUTE
CUTTHROAT
Oncorhynchus
clarki
seleniris
Fish
STEELHEAD,
UPPER
WILLAMETTE
Oncorhynchus
(=
Salmo)
mykiss
Fish
RIVER
POPULATION
TROUT,
LAHONTAN
CUTTHROAT
Oncorhynchus
clarki
henshawi
Fish
STEELHEAD,
SNAKE
RIVER
BASIN
Oncorhynchus
(=
Salmo)
mykiss
Fish
POPULATION
PUPFISH,
DESERT
Cyprinodon
macularius
Fish
SUCKER,
SANTA
ANA
Catostomus
santaanae
Fish
SUCKER,
RAZORBACK
Xyrauchen
texanus
Fish
STURGEON,
SHORTNOSE
Acipenser
brevirostrum
Fish
STURGEON,
PALLID
Scaphirhynchus
albus
Fish
STURGEON,
GULF
Acipenser
oxyrinchus
desotoi
Fish
STURGEON,
ALABAMA
Scaphirhynchus
suttkusi
Fish
CHUB,
OREGON
Oregonichthys
crameri
Fish
STICKLEBACK,
UNARMORED
Gasterosteus
aculeatus
williamsoni
Fish
THREESPINE
TROUT,
LITTLE
KERN
GOLDEN
Oncorhynchus
aguabonita
whitei
Fish
STEELHEAD,
CALIFORNIA
CENTRAL
Oncorhynchus
(=
Salmo)
mykiss
Fish
VALLEY
POP
SMELT,
DELTA
Hypomesus
transpacificus
Fish
MADTOM,
SCIOTO
Noturus
trautmani
Fish
GOBY,
TIDEWATER
Eucyclogobius
newberryi
Fish
SILVERSIDE,
WACCAMAW
Menidia
extensa
Fish
SQUAWFISH,
COLORADO
Ptychocheilus
lucius
Fish
STEELHEAD,
CENTRAL
CALIFORNIA
Oncorhynchus
(=
Salmo)
mykiss
Fish
POPULATION
STEELHEAD,
LOWER
COLUMBIA
Oncorhynchus
(=
Salmo)
mykiss
Fish
RIVER
POPULATION
CHUB,
BONYTAIL
Gila
elegans
Fish
STEELHEAD,
MIDDLE
COLUMBIA
Oncorhynchus
(=
Salmo)
mykiss
Fish
RIVER
POPULATION
SHINER,
TOPEKA
Notropis
topeka
(=
tristis)
Fish
SHINER,
CAPE
FEAR
Notropis
mekistocholas
Fish
SHINER,
CAHABA
Notropis
cahabae
Fish
SHINER,
ARKANSAS
RIVER
Notropis
girardi
Fish
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June
09,
2005
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STEELHEAD,
NORTHERN
Oncorhynchus
(=
Salmo)
mykiss
Fish
CALIFORNIA
POPULATION
SHINER,
BLUE
Cyprinella
caerulea
Fish
BUTTERFLY,
SAINT
FRANCIS'
SATYR
Neonympha
mitchellii
francisci
Insect
BUTTERFLY,
QUINO
CHECKERSPOT
Euphydryas
editha
quino
(=
E.
e.
wrighti)
Insect
BUTTERFLY,
BEHREN'S
SILVERSPOT
Speyeria
zerene
behrensii
Insect
BUTTERFLY,
BAY
CHECKERSPOT
Euphydryas
editha
bayensis
Insect
BUTTERFLY,
MITCHELL'S
SATYR
Neonympha
mitchellii
mitchellii
Insect
MOTH,
BLACKBURN'S
SPHINX
Manduca
blackburni
Insect
BUTTERFLY,
KARNER
BLUE
Lycaeides
melissa
samuelis
Insect
BUTTERFLY,
SAN
BRUNO
ELFIN
Callophrys
mossii
bayensis
Insect
BUTTERFLY,
LOTIS
BLUE
Lycaeides
argyrognomon
lotis
Insect
BEETLE,
PURITAN
TIGER
Cicindela
puritana
Insect
SKIPPER,
LAGUNA
MOUNTAIN
Pyrgus
ruralis
lagunae
Insect
MOTH,
KERN
PRIMROSE
SPHINX
Euproserpinus
euterpe
Insect
BUTTERFLY,
MISSION
BLUE
Icaricia
icarioides
missionensis
Insect
BEETLE,
VALLEY
ELDERBERRY
Desmocerus
californicus
dimorphus
Insect
LONGHORN
BEETLE,
DELTA
GREEN
GROUND
Elaphrus
viridis
Insect
BUTTERFLY,
CALLIPPE
SILVERSPOT
Speyeria
callippe
callippe
Insect
BUTTERFLY,
FENDER'S
BLUE
Icaricia
icarioides
fenderi
Insect
BEETLE,
OHLONE
TIGER
Cicindela
ohlone
Insect
BEETLE,
NORTHEASTERN
BEACH
Cicindela
dorsalis
dorsalis
Insect
TIGER
FLY,
DELHI
SANDS
FLOWER­
LOVING
Rhaphiomidas
terminatus
abdominalis
Insect
BEETLE,
HUNGERFORD'S
CRAWLING
Brychius
hungerfordi
Insect
WATER
BUTTERFLY,
SMITH'S
BLUE
Euphilotes
enoptes
smithi
Insect
BUTTERFLY,
MYRTLE'S
SILVERSPOT
Speyeria
zerene
myrtleae
Insect
BEETLE,
AMERICAN
BURYING
Nicrophorus
americanus
Insect
GRASSHOPPER,
ZAYANTE
Trimerotropis
infantilis
Insect
BAND­
WINGED
DRAGONFLY,
HINES
EMERALD
Somatochlora
hineana
Insect
BEETLE,
MOUNT
HERMON
JUNE
Polyphylla
barbata
Insect
BAT,
HAWAIIAN
HOARY
Lasiurus
cinereus
semotus
Mammal
BAT,
INDIANA
Myotis
sodalis
Mammal
FOX,
SANTA
CRUZ
ISLAND
Urocyon
littoralis
santacruzae
Mammal
FOX,
SANTA
ROSA
ISLAND
Urocyon
littoralis
santarosae
Mammal
BAT,
OZARK
BIG­
EARED
Corynorhinus
(=
Plecotus)
townsendii
Mammal
KANGAROO
RAT,
FRESNO
Dipodomys
nitratoides
exilis
Mammal
KANGAROO
RAT,
STEPHENS'
Dipodomys
stephensi
(
incl.
D.
cascus)
Mammal
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June
09,
2005
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FERRET,
BLACK­
FOOTED
Mustela
nigripes
Mammal
KANGAROO
RAT,
SAN
BERNARDINO
Dipodomys
merriami
parvus
Mammal
KANGAROO
RAT,
MORRO
BAY
Dipodomys
heermanni
morroensis
Mammal
WOODRAT,
RIPARIAN
Neotoma
fuscipes
riparia
Mammal
WOLF,
RED
Canis
rufus
Mammal
WOLF,
GRAY
Canis
lupus
Mammal
OCELOT
Leopardus
(=
Felis)
pardalis
Mammal
OTTER,
SOUTHERN
SEA
Enhydra
lutris
nereis
Mammal
KANGAROO
RAT,
GIANT
Dipodomys
ingens
Mammal
LYNX,
CANADA
Lynx
canadensis
Mammal
FOX,
SAN
JOAQUIN
KIT
Vulpes
macrotis
mutica
Mammal
MOUSE,
SALT
MARSH
HARVEST
Reithrodontomys
raviventris
Mammal
MOUSE,
PACIFIC
POCKET
Perognathus
longimembris
pacificus
Mammal
BEAR,
LOUISIANA
BLACK
Ursus
americanus
luteolus
Mammal
MOUSE,
CHOCTAWHATCHEE
BEACH
Peromyscus
polionotus
allophrys
Mammal
FOX,
SAN
MIGUEL
ISLAND
Urocyon
littoralis
littoralis
Mammal
MOUNTAIN
BEAVER,
POINT
ARENA
Aplodontia
rufa
nigra
Mammal
DEER,
COLUMBIAN
WHITE­
TAILED
Odocoileus
virginianus
leucurus
Mammal
WHALE,
NORTHERN
RIGHT
Eubalaena
glacialis
Mammal
CARIBOU,
WOODLAND
Rangifer
tarandus
caribou
Mammal
SQUIRREL,
DELMARVA
PENINSULA
Sciurus
niger
cinereus
Mammal
FOX
RABBIT,
PYGMY
Brachylagus
idahoensis
Mammal
RABBIT,
RIPARIAN
BRUSH
Sylvilagus
bachmani
riparius
Mammal
SHREW,
BUENA
VISTA
Sorex
ornatus
relictus
Mammal
SHEEP,
PENINSULAR
BIGHORN
Ovis
canadensis
Mammal
BAT,
VIRGINIA
BIG­
EARED
Corynorhinus
(=
Plecotus)
townsendii
Mammal
virginianus
SEAL,
GUADALUPE
FUR
Arctocephalus
townsendi
Mammal
SEAL,
HAWAIIAN
MONK
Monachus
schauinslandi
Mammal
KANGAROO
RAT,
TIPTON
Dipodomys
nitratoides
nitratoides
Mammal
MANATEE,
WEST
INDIAN
Trichechus
manatus
Mammal
BEAR,
GRIZZLY
Ursus
arctos
horribilis
Mammal
GOLDENROD,
HOUGHTON'S
Solidago
houghtonii
Plant
GOLDFIELDS,
BURKE'S
Lasthenia
burkei
Plant
GOLDEN
SUNBURST,
HARTWEG'S
Pseudobahia
bahiifolia
Plant
IRIS,
DWARF
LAKE
Iris
lacustris
Plant
HAHA
(
CYANEA
COPELANDII
SSP.
Cyanea
copelandii
ssp.
copelandii
Plant
COPELANDII)

HA'IWALE
(
CYRTANDRA
Cyrtandra
limahuliensis
Plant
LIMAHULIENSIS)

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June
09,
2005
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HA'IWALE
(
CYRTANDRA
GIFFARDII)
Cyrtandra
giffardii
Plant
HAHA
(
CYANEA
SHIPMANII)
Cyanea
shipmannii
Plant
JEWELFLOWER,
CALIFORNIA
Caulanthus
californicus
Plant
IPOMOPSIS,
HOLY
GHOST
Ipomopsis
sancti­
spiritus
Plant
HAHA
(
CYANEA
STICTOPHYLLA)
Cyanea
stictophylla
Plant
HAHA
(
CYANEA
HAMATIFLORA
SSP.
Cyanea
hamatiflora
carlsonii
Plant
CARLSONII)

KAMAKAHALA
(
LABORDIA
Labordia
lydgatei
Plant
LYDGATEI)

HAHA
(
CYANEA
REMYI)
Cyanea
remyi
Plant
KAMAKAHALA
(
LABORDIA
Labordia
tinifolia
var.
wahiawaensis
Plant
TINIFOLIA
VAR.
WAHIAWAEN
GOLDFIELDS,
CONTRA
COSTA
Lasthenia
conjugens
Plant
GOOSEBERRY,
MICCOSUKEE
Ribes
echinellum
Plant
(
FLORIDA)

GOUANIA
MEYENII
(
NCN)
Gouania
meyenii
Plant
GRASS,
CALIFORNIA
ORCUTT
Orcuttia
californica
Plant
GRASS,
COLUSA
Neostapfia
colusana
Plant
FOUR­
O'CLOCK,
MACFARLANE'S
Mirabilis
macfarlanei
Plant
GRASS,
HAIRY
ORCUTT
Orcuttia
pilosa
Plant
JOINT­
VETCH,
SENSITIVE
Aeschynomene
virginica
Plant
HEAU
(
EXOCARPOS
LUTEOLUS)
Exocarpos
luteolus
Plant
FRITILLARY,
GENTNER'S
Fritillaria
gentneri
Plant
HAPLOSTACHYS
HAPLOSTACHYA
Haplostachys
haplostachya
Plant
(
NCN)

HALA
PEPE
(
PLEOMELE
Pleomele
hawaiiensis
Plant
FRINGEPOD,
SANTA
CRUZ
ISLAND
Thysanocarpus
conchuliferus
Plant
HARPERELLA
Ptilimnium
nodosum
Plant
HAU
KAUHIWI
(
HIBISCADELPHUS
Hibiscadelphus
woodii
Plant
WOODI)

FRINGE
TREE,
PYGMY
Chionanthus
pygmaeus
Plant
GEOCARPON
MINIMUM
Geocarpon
minimum
Plant
GERARDIA,
SANDPLAIN
Agalinis
acuta
Plant
HAU
KUAHIWI
(
HIBISCADELPHUS
Hibiscadelphus
distans
Plant
DISTANS)

GILIA,
HOFFMANN'S
Gilia
tenuiflora
ssp.
hoffmannii
Plant
SLENDER­
FLOWERED
GRASS,
SACRAMENTO
ORCUTT
Orcuttia
viscida
Plant
HYPERICUM,
HIGHLANDS
SCRUB
Hypericum
cumulicola
Plant
HEARTLEAF,
DWARF­
FLOWERED
Hexastylis
naniflora
Plant
ILIAU
(
WILKESIA
HOBDYI)
Wilkesia
hobdyi
Plant
HEDYOTIS
ST.­
JOHNII
(
NCN)
Hedyotis
st.­
johnii
Plant
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June
09,
2005
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HESPEROMANNIA
LYDGATEI
(
NCN)
Hesperomannia
lydgatei
Plant
HIBISCUS,
CLAY'S
Hibiscus
clayi
Plant
GRASS,
SLENDER
ORCUTT
Orcuttia
tenuis
Plant
HAHA
(
CYANEA
RECTA)
Cyanea
recta
Plant
GRASS,
SOLANO
Tuctoria
mucronata
Plant
HAHA
(
CYANEA
PLATYPHYLLA)
Cyanea
platyphylla
Plant
GILIA,
MONTEREY
Gilia
tenuiflora
ssp.
arenaria
Plant
HILO
ISCHAEMUM
(
ISCHAEMUM
Ischaemum
byrone
Plant
BYRONE)

HAHA
(
CYANEA
ASARIFOLIA)
Cyanea
asarifolia
Plant
HOLEI
(
OCHROSIA
KILAUEAENSIS)
Ochrosia
kilaueaensis
Plant
HOWELLIA,
WATER
Howellia
aquatilis
Plant
HAREBELLS,
AVON
PARK
Crotalaria
avonensis
Plant
GRASS,
SAN
JOAQUIN
VALLEY
Orcuttia
inaequalis
Plant
ORCUTT
BIRD'S­
BEAK,
PENNELL'S
Cordylanthus
tenuis
ssp.
capillaris
Plant
AUPAKA
(
ISODENDRION
Isodendrion
longifolium
Plant
LONGIFOLIUM)

'
AWIWI
(
CENTAURIUM
Centaurium
sebaeoides
Plant
'
AWIWI
(
HEDYOTIS
COOKIANA)
Hedyotis
cookiana
Plant
BACCHARIS,
ENCINITAS
Baccharis
vanessae
Plant
BARBARA'S
BUTTONS,
MOHR'S
Marshallia
mohrii
Plant
BARBERRY,
ISLAND
Berberis
pinnata
ssp.
insularis
Plant
BARBERRY,
NEVIN'S
Berberis
nevinii
Plant
BEAKED­
RUSH,
KNIESKERN'S
Rhynchospora
knieskernii
Plant
BEARGRASS,
BRITTON'S
Nolina
brittoniana
Plant
BONAMIA,
FLORIDA
Bonamia
grandiflora
Plant
BIRD'S­
BEAK,
PALMATE­
BRACTED
Cordylanthus
palmatus
Plant
ASTER,
FLORIDA
GOLDEN
Chrysopsis
floridana
Plant
BIRD'S­
BEAK,
SALT
MARSH
Cordylanthus
maritimus
ssp.
maritimus
Plant
BIRD'S­
BEAK,
SOFT
Cordylanthus
mollis
ssp.
mollis
Plant
BLADDERPOD,
MISSOURI
Lesquerella
filiformis
Plant
BLADDERPOD,
WHITE
Lesquerella
pallida
Plant
BLAZING
STAR,
SCRUB
Liatris
ohlingerae
Plant
BLUEGRASS,
HAWAIIAN
Poa
sandvicensis
Plant
BLUEGRASS,
MANN'S
(
POA
MANNII)
Poa
mannii
Plant
BLUEGRASS,
SAN
BERNARDINO
Poa
atropurpurea
Plant
CHECKER­
MALLOW,
NELSON'S
Sidalcea
nelsoniana
Plant
BEDSTRAW,
ISLAND
Galium
buxifolium
Plant
ALOPECURUS,
SONOMA
Alopecurus
aequalis
var.
sonomensis
Plant
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June
09,
2005
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ADOBE
SUNBURST,
SAN
JOAQUIN
Pseudobahia
peirsonii
Plant
A'E
(
ZANTHOXYLUM
DIPETALUM
Zanthoxylum
dipetalum
var.
tomentosum
Plant
VAR.
TOMENTOSUM)

A'E
(
ZANTHOXYLUM
HAWAIIENSE)
Zanthoxylum
hawaiiense
Plant
'
AIEA
(
NOTHOCESTRUM
Nothocestrum
breviflorum
Plant
BREVIFLORUM)

'
AIEA
(
NOTHOCESTRUM
Nothocestrum
peltatum
Plant
'
AKOKO
(
EUPHORBIA
Euphorbia
haeleeleana
Plant
ALANI
(
MELICOPE
HAUPUENSIS)
Melicope
haupuensis
Plant
ALANI
(
MELICOPE
KNUDSENII)
Melicope
knudsenii
Plant
ALANI
(
MELICOPE
PALLIDA)
Melicope
pallida
Plant
AUPAKA
(
ISODENDRION
Isodendrion
laurifolium
Plant
LAURIFOLIUM)

ALANI
(
MELICOPE
Melicope
zahlbruckneri
Plant
AUPAKA
(
ISODENDRION
HOSAKAE)
Isodendrion
hosakae
Plant
ALSINIDENDRON
VISCOSUM
(
NCN)
Alsinidendron
viscosum
Plant
AMARANTH,
SEABEACH
Amaranthus
pumilus
Plant
AMBROSIA,
SAN
DIEGO
Ambrosia
pumila
Plant
Amole,
Camatta
Canyon
Chlorogalum
purpureum
var.
reductum
Plant
AMOLE,
PURPLE
Chlorogalum
purpureum
var.
purpureum
Plant
AMPHIANTHUS,
LITTLE
Amphianthus
pusillus
Plant
'
ANUNU
(
SICYOS
ALBA)
Sicyos
alba
Plant
ASPLENIUM
FRAGILE
VAR.
Asplenium
fragile
var.
insulare
Plant
INSULARE
(
NCN)

ASTER,
DECURRENT
FALSE
Boltonia
decurrens
Plant
BRODIAEA,
THREAD­
LEAVED
Brodiaea
filifolia
Plant
ALANI
(
MELICOPE
Melicope
quadrangularis
Plant
QUADRANGULARIS)

DROPWORT,
CANBY'S
Oxypolis
canbyi
Plant
CROWNSCALE,
SAN
JACINTO
Atriplex
coronata
var.
notatior
Plant
CYANEA
UNDULATA
(
NCN)
Cyanea
undulata
Plant
CYPRESS,
GOWEN
Cupressus
goveniana
ssp.
goveniana
Plant
CYPRESS,
SANTA
CRUZ
Cupressus
abramsiana
Plant
DAISY,
LAKESIDE
Hymenoxys
herbacea
Plant
DAISY,
PARISH'S
Erigeron
parishii
Plant
DAISY,
WILLAMETTE
Erigeron
decumbens
var.
decumbens
Plant
DAWN­
FLOWER,
TEXAS
PRAIRIE
Hymenoxys
texana
Plant
(=
TEXAS
BITTERWEED
DELISSEA
RHYTODISPERMA
(
NCN)
Delissea
rhytidosperma
Plant
BONAMIA
MENZIESII
(
NCN)
Bonamia
menziesii
Plant
DIELLIA
PALLIDA
(
NCN)
Diellia
pallida
Plant
CLOVER,
SHOWY
INDIAN
Trifolium
amoenum
Plant
Thursday,
June
09,
2005
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DUBAUTIA
LATIFOLIA
Dubautia
latifolia
Plant
DUBAUTIA
PAUCIFLORULA
Dubautia
pauciflorula
Plant
DUDLEYA,
MARCESCENT
Dudleya
cymosa
ssp.
marcescens
Plant
DUDLEYA,
SANTA
CLARA
VALLEY
Dudleya
setchellii
Plant
DUDLEYA,
SANTA
CRUZ
ISLAND
Dudleya
nesiotica
Plant
EVENING­
PRIMROSE,
ANTIOCH
Oenothera
deltoides
ssp.
howellii
Plant
DUNES
FERN,
AMERICAN
HART'S­
TONGUE
Asplenium
scolopendrium
var.
Plant
FERN,
PENDANT
KIHI
Adenophorus
periens
Plant
(
ADENOPHORUS
PERIENS)

FIDDLENECK,
LARGE­
FLOWERED
Amsinckia
grandiflora
Plant
DIELLIA
ERECTA
(
NCN)
Diellia
erecta
Plant
CHAFFSEED,
AMERICAN
Schwalbea
americana
Plant
BUCKWHEAT,
SCRUB
Eriogonum
longifolium
var.
Plant
BULRUSH,
NORTHEASTERN
Scirpus
ancistrochaetus
Plant
(=
BARBED
BRISTLE)

BUSH­
CLOVER,
PRAIRIE
Lespedeza
leptostachya
Plant
BUSHMALLOW,
SANTA
CRUZ
Malacothamnus
fasciculatus
var.
Plant
BUTTON­
CELERY,
SAN
DIEGO
Eryngium
aristulatum
var.
parishii
Plant
CACTUS,
BAKERSFIELD
Opuntia
treleasei
Plant
CACTUS,
UINTA
BASIN
HOOKLESS
Sclerocactus
glaucus
Plant
CAMPION,
FRINGED
Silene
polypetala
Plant
CATCHFLY,
SPALDING'S
Silene
spaldingii
Plant
CROWN­
BEARD,
BIG­
LEAVED
Verbesina
dissita
Plant
CEANOTHUS,
VAIL
LAKE
Ceanothus
ophiochilus
Plant
CONEFLOWER,
SMOOTH
Echinacea
laevigata
Plant
CHAMAESYCE
HALEMANUI
Chamaesyce
halemanui
Plant
CHECKER­
MALLOW,
KECK'S
Sidalcea
keckii
Plant
CHECKER­
MALLOW,
KENWOOD
Sidalcea
oregana
ssp.
valida
Plant
MARSH
CLADONIA,
FLORIDA
PERFORATE
Cladonia
perforata
Plant
CLARKIA,
PISMO
Clarkia
speciosa
ssp.
immaculata
Plant
CLARKIA,
SPRINGVILLE
Clarkia
springvillensis
Plant
CLARKIA,
VINE
HILL
Clarkia
imbricata
Plant
CLOVER,
MONTEREY
Trifolium
trichocalyx
Plant
CLOVER,
RUNNING
BUFFALO
Trifolium
stoloniferum
Plant
FLANNELBUSH,
MEXICAN
Fremontodendron
mexicanum
Plant
CEANOTHUS,
COYOTE
Ceanothus
ferrisae
Plant
SCHIEDEA
NUTTALLII
(
NCN)
Schiedea
nuttallii
Plant
REMYA
KAUAIENSIS
(
NCN)
Remya
kauaiensis
Plant
REMYA
MONTGOMERYI
(
NCN)
Remya
montgomeryi
Plant
Thursday,
June
09,
2005
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ROCK­
CRESS,
HOFFMANN'S
Arabis
hoffmannii
Plant
ROCK­
CRESS,
MCDONALD'S
Arabis
mcdonaldiana
Plant
ROSEMARY,
SHORT­
LEAVED
Conradina
brevifolia
Plant
ROSEROOT,
LEEDY'S
Sedum
integrifolium
ssp.
leedyi
Plant
SANDLACE
Polygonella
myriophylla
Plant
SAND­
VERBENA,
LARGE­
FRUITED
Abronia
macrocarpa
Plant
SANDWORT,
MARSH
Arenaria
paludicola
Plant
SCHIEDEA
HELLERI
(
NCN)
Schiedea
helleri
Plant
PHYLLOSTEGIA
KNUDSENII
(
NCN)
Phyllostegia
knudsenii
Plant
SCHIEDEA
MEMBRANACEA
(
NCN)
Schiedea
membranacea
Plant
QUILLWORT,
BLACK­
SPORED
Isoetes
melanospora
Plant
SCHIEDEA
SPERGULINA
VAR.
Schiedea
spergulina
var.
leiopoda
Plant
LEIOPODA
(
NCN)

SCHIEDEA
SPERGULINA
VAR.
Schiedea
spergulina
var.
spergulina
Plant
SPERGULINA
(
NCN)

SEA­
BLITE,
CALIFORNIA
Suaeda
californica
Plant
SEDGE,
WHITE
Carex
albida
Plant
SILENE
HAWAIIENSIS
(
NCN)
Silene
hawaiiensis
Plant
SILENE
LANCEOLATA
(
NCN)
Silene
lanceolata
Plant
SILVERSWORD,
KA'U
Argyroxiphium
kauense
Plant
(
ARGYROXIPHIUM
KAUENSE)

SILVERSWORD,
MAUNA
KEA
Argyroxiphium
sandwicense
ssp.
Plant
('
AHINAHINA)
sandwicense
SNEEZEWEED,
VIRGINIA
Helenium
virginicum
Plant
SPERMOLEPIS
HAWAIIENSIS
(
NCN)
Spermolepis
hawaiiensis
Plant
SCHIEDEA
KAUAIENSIS
(
NCN)
Schiedea
kauaiensis
Plant
KAUILA
(
COLUBRINA
Colubrina
oppositifolia
Plant
PHYLLOSTEGIA
VELUTINA
(
NCN)
Phyllostegia
velutina
Plant
PHYLLOSTEGIA
WAIMEAE
(
NCN)
Phyllostegia
waimeae
Plant
PHYLLOSTEGIA
WARSHAUERI
(
NCN)
Phyllostegia
warshaueri
Plant
PHYLLOSTEGIA
WAWRANA
(
NCN)
Phyllostegia
wawrana
Plant
PINK,
SWAMP
Helonias
bullata
Plant
PINKROOT,
GENTIAN
Spigelia
gentianoides
Plant
PIPERIA,
YADON'S
Piperia
yadonii
Plant
PITCHER­
PLANT,
ALABAMA
Sarracenia
rubra
alabamensis
Plant
CANEBRAKE
PITCHER­
PLANT,
GREEN
Sarracenia
oreophila
Plant
PLATANTHERA
HOLOCHILA
(
NCN)
Platanthera
holochila
Plant
RATTLEWEED,
HAIRY
Baptisia
arachnifera
Plant
POA
SIPHONOGLOSSA
(
NCN)
Poa
siphonoglossa
Plant
QUILLWORT,
LOUISIANA
Isoetes
louisianensis
Plant
Thursday,
June
09,
2005
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POGONIA,
SMALL
WHORLED
Isotria
medeoloides
Plant
MINT,
OTAY
MESA
Pogogyne
nudiuscula
Plant
POLYGONUM,
SCOTT'S
VALLEY
Polygonum
hickmanii
Plant
PONDBERRY
Lindera
melissifolia
Plant
POPOLO
'
AIAKEAKUA
(
SOLANUM
Solanum
sandwicense
Plant
SANDWICENSE)

POPOLO
KU
MAI
(
SOLANUM
Solanum
incompletum
Plant
INCOMPLETUM)

POTATO­
BEAN,
PRICE'S
Apios
priceana
Plant
POTENTILLA,
HICKMAN'S
Potentilla
hickmanii
Plant
PUSSYPAWS,
MARIPOSA
Calyptridium
pulchellum
Plant
PU'UKA'A
(
CYPERUS
Cyperus
trachysanthos
Plant
TRACHYSANTHOS)

SPINEFLOWER,
MONTEREY
Chorizanthe
pungens
var.
pungens
Plant
PLUM,
SCRUB
Prunus
geniculata
Plant
WATERCRESS,
GAMBEL'S
Rorippa
gambellii
Plant
SPINEFLOWER,
BEN
LOMOND
Chorizanthe
pungens
var.
hartwegiana
Plant
TORREYA,
FLORIDA
Torreya
taxifolia
Plant
TRILLIUM,
RELICT
Trillium
reliquum
Plant
TUCTORIA,
GREEN'S
Tuctoria
greenei
Plant
UHIUHI
(
CAESALPINIA
KAVAIENSIS)
Caesalpinia
kavaiense
Plant
VETCH,
HAWAIIAN
(
VICIA
Vicia
menziesii
Plant
VIGNA
O­
WAHUENSIS
(
NCN)
Vigna
o­
wahuensis
Plant
VIOLA
HELENAE
(
NCN)
Viola
helenae
Plant
WAHINE
NOHO
KULA
Isodendrion
pyrifolium
Plant
(
ISODENDRION
PYRIFOLIUM)

WALLFLOWER,
BEN
LOMOND
Erysimum
teretifolium
Plant
THORNMINT,
SAN
DIEGO
Acanthomintha
ilicifolia
Plant
WAREA,
WIDE­
LEAF
Warea
amplexifolia
Plant
THISTLE,
SUISUN
Cirsium
hydrophilum
var.
hydrophilum
Plant
WATER­
PLANTAIN,
KRAL'S
Sagittaria
secundifolia
Plant
WAWAE'IOLE
(
PHLEGMARIURUS
Huperzia
mannii
Plant
(=
HUPERZIA)
MANNII)

WAWAE'IOLE
(
PHLEGMARIURUS
Lycopodium
(=
Phlegmariurus)
nutans
Plant
(=
LYCOPODIUM)
NUTAN
WHITLOW­
WORT,
PAPERY
Paronychia
chartacea
Plant
WILD­
BUCKWHEAT,
CLAY­
LOVING
Eriogonum
pelinophilum
Plant
WINGS,
PIGEON
Clitoria
fragrans
Plant
WIREWEED
Polygonella
basiramia
Plant
WOOLLY­
STAR,
SANTA
ANA
RIVER
Eriastrum
densifolium
ssp.
sanctorum
Plant
WOOLLY­
THREADS,
SAN
JOAQUIN
Monolopia
(=
Lembertia)
congdonii
Plant
XYLOSMA
CRENATUM
(
NCN)
Xylosma
crenatum
Plant
Thursday,
June
09,
2005
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YERBA
SANTA,
LOMPOC
Eriodictyon
capitatum
Plant
WALLFLOWER,
MENZIE'S
Erysimum
menziesii
Plant
SUNFLOWER,
EGGERT'S
Helianthus
eggertii
Plant
PO'E
(
PORTULACA
SCLEROCARPA)
Portulaca
sclerocarpa
Plant
SPINEFLOWER,
ORCUTT'S
Chorizanthe
orcuttiana
Plant
SPINEFLOWER,
ROBUST
Chorizanthe
robusta
(
incl.
vars.
robusta
Plant
and
hartwegii)

SPINEFLOWER,
SCOTTS
VALLEY
Chorizanthe
robusta
var.
hartwegii
Plant
SPINEFLOWER,
SLENDER­
HORNED
Dodecahema
leptoceras
Plant
SPINEFLOWER,
SONOMA
Chorizanthe
valida
Plant
SPURGE,
HOOVER'S
Chamaesyce
hooveri
Plant
STENOGYNE
ANGUSTIFOLIA
(
NCN)
Stenogyne
angustifolia
var.
angustifolia
Plant
STENOGYNE
CAMPANULATA
(
NCN)
Stenogyne
campanulata
Plant
STICKYSEED,
BAKER'S
Blennosperma
bakeri
Plant
THORNMINT,
SAN
MATEO
Acanthomintha
obovata
ssp.
duttonii
Plant
SUMAC,
MICHAUX'S
Rhus
michauxii
Plant
SPINEFLOWER,
HOWELL'S
Chorizanthe
howellii
Plant
SUNFLOWER,
SAN
MATEO
WOOLLY
Eriophyllum
latilobum
Plant
SUNFLOWER,
SCHWEINITZ'S
Helianthus
schweinitzii
Plant
TARPLANT,
GAVIOTA
Deinandra
increscens
ssp.
villosa
Plant
TARPLANT,
OTAY
Deinandra
(=
Hemizonia)
conjugens
Plant
TARPLANT,
SANTA
CRUZ
Holocarpha
macradenia
Plant
TETRAMOLOPIUM
ARENARIUM
Tetramolopium
arenarium
Plant
THELYPODY,
HOWELL'S
Thelypodium
howellii
spectabilis
Plant
SPECTACULAR
THISTLE,
CHORRO
CREEK
BOG
Cirsium
fontinale
var.
obispoense
Plant
THISTLE,
FOUNTAIN
Cirsium
fontinale
var.
fontinale
Plant
THISTLE,
LA
GRACIOSA
Cirsium
loncholepis
Plant
THISTLE,
PITCHER'S
Cirsium
pitcheri
Plant
STONECROP,
LAKE
COUNTY
Parvisedum
leiocarpum
Plant
LYSIMACHIA
FILIFOLIA
(
NCN)
Lysimachia
filifolia
Plant
MARISCUS
FAURIEI
(
NCN)
Mariscus
fauriei
Plant
LOMATIUM,
BRADSHAW'S
Lomatium
bradshawii
Plant
LOMATIUM,
COOK'S
Lomatium
cookii
Plant
LOOSESTRIFE,
ROUGH­
LEAVED
Lysimachia
asperulaefolia
Plant
LOULU
(
PRITCHARDIA
AFFINIS)
Pritchardia
affinis
Plant
LOULU
(
PRITCHARDIA
Pritchardia
napaliensis
Plant
LOULU
(
PRITCHARDIA
Pritchardia
schattaueri
Plant
LOULU
(
PRITCHARDIA
VISCOSA)
Pritchardia
viscosa
Plant
LOUSEWORT,
FURBISH
Pedicularis
furbishiae
Plant
Thursday,
June
09,
2005
Page
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06)
    
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147
LUPINE,
CLOVER
Lupinus
tidestromii
Plant
LOBELIA
NIIHAUENSIS
(
NCN)
Lobelia
niihauensis
Plant
LUPINE,
SCRUB
Lupinus
aridorum
Plant
LIVEFOREVER,
SANTA
BARBARA
Dudleya
traskiae
Plant
ISLAND
MAHOE
(
ALECTRYON
Alectryon
macrococcus
Plant
MACROCOCCUS)

MAKOU
(
PEUCEDANUM
Peucedanum
sandwicense
Plant
SANDWICENSE)

MALACOTHRIX,
ISLAND
Malacothrix
squalida
Plant
MALACOTHRIX,
SANTA
CRUZ
Malacothrix
indecora
Plant
MALLOW,
KERN
Eremalche
kernensis
Plant
MANZANITA,
DEL
MAR
Arctostaphylos
glandulosa
ssp.
crassifolia
Plant
MANZANITA,
MORRO
Arctostaphylos
morroensis
Plant
POLYGALA,
LEWTON'S
Polygala
lewtonii
Plant
MA'O
HAU
HELE
(
HIBISCUS
Hibiscus
brackenridgei
Plant
BRACKENRIDGEI)

PHLOX,
TEXAS
TRAILING
Phlox
nivalis
ssp.
texensis
Plant
MAPELE
(
CYRTANDRA
Cyrtandra
cyaneoides
Plant
LUPINE,
NIPOMO
MESA
Lupinus
nipomensis
Plant
LAU'EHU
(
PANICUM
NIIHAUENSE)
Panicum
niihauense
Plant
KAULU
(
PTERALYXIA
KAUAIENSIS)
Pteralyxia
kauaiensis
Plant
KIO'ELE
(
HEDYOTIS
CORIACEA)
Hedyotis
coriacea
Plant
KIPONAPONA
(
PHYLLOSTEGIA
Phyllostegia
racemosa
Plant
RACEMOSA)

KOKI'O
(
KOKIA
DRYNARIOIDES)
Kokia
drynarioides
Plant
KOKI'O
(
KOKIA
KAUAIENSIS)
Kokia
kauaiensis
Plant
KOKI'O
KE'OKE'O
(
HIBISCUS
Hibiscus
waimeae
ssp.
hannerae
Plant
WAIMEAE
SSP.
HANNER
KOLEA
(
MYRSINE
LINEARIFOLIA)
Myrsine
linearifolia
Plant
KO'OLOA'ULA
(
ABUTILON
Abutilon
menziesii
Plant
KUAWAWAENOHU
Alsinidendron
lychnoides
Plant
(
ALSINIDENDRON
LYCHNOIDES)

LADIES'­
TRESSES,
NAVASOTA
Spiranthes
parksii
Plant
LOCOWEED,
FASSETT'S
Oxytropis
campestris
var.
chartacea
Plant
LARKSPUR,
YELLOW
Delphinium
luteum
Plant
MA'OLI'OLI
(
SCHIEDEA
Schiedea
apokremnos
Plant
LAUKAHI
KUAHIWI
(
PLANTAGO
Plantago
hawaiensis
Plant
HAWAIENSIS)

LAUKAHI
KUAHIWI
(
PLANTAGO
Plantago
princeps
Plant
PRINCEPS)

LAULIHILIHI
(
SCHIEDEA
Schiedea
stellarioides
Plant
STELLARIOIDES)

Thursday,
June
09,
2005
Page
17
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06)
    
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147
LAYIA,
BEACH
Layia
carnosa
Plant
LEATHER­
FLOWER,
ALABAMA
Clematis
socialis
Plant
LEATHER­
FLOWER,
MOREFIELD'S
Clematis
morefieldii
Plant
LESSINGIA,
SAN
FRANCISCO
Lessingia
germanorum
(=
L.
g.
var.
Plant
germanorum)

LILY,
MINNESOTA
TROUT
Erythronium
propullans
Plant
LILY,
PITKIN
MARSH
Lilium
pardalinum
ssp.
pitkinense
Plant
LILY,
WESTERN
Lilium
occidentale
Plant
LIPOCHAETA
VENOSA
(
NCN)
Lipochaeta
venosa
Plant
LADIES'­
TRESSES,
UTE
Spiranthes
diluvialis
Plant
'
OHA
WAI
(
CLERMONTIA
Clermontia
drepanomorpha
Plant
DREPANOMORPHA)

ZIZIPHUS,
FLORIDA
Ziziphus
celata
Plant
MONKEY­
FLOWER,
MICHIGAN
Mimulus
glabratus
var.
michiganensis
Plant
MONKSHOOD,
NORTHERN
WILD
Aconitum
noveboracense
Plant
MOUNTAINBALM,
INDIAN
KNOB
Eriodictyon
altissimum
Plant
'
OHA
WAI
(
CLERMONTIA
PELEANA)
Clermontia
peleana
Plant
'
OHA
WAI
(
CLERMONTIA
Clermontia
lindseyana
Plant
LINDSEYANA)

MUNROIDENDRON
RACEMOSUM
Munroidendron
racemosum
Plant
(
NCN)

MUSTARD,
CARTER'S
Warea
carteri
Plant
NANI
WAI'ALE'ALE
(
VIOLA
Viola
kauaiensis
var.
wahiawaensis
Plant
KAUAENSIS
VAR.
WAHIAW
ACHYRANTHES
MUTICA
(
NCN)
Achyranthes
mutica
Plant
NAVARRETIA,
MANY­
FLOWERED
Navarretia
leucocephala
ssp.
plieantha
Plant
MINT,
SAN
DIEGO
MESA
Pogogyne
abramsii
Plant
'
OHA
(
DELISSEA
UNDULATA)
Delissea
undulata
Plant
MANZANITA,
SANTA
ROSA
ISLAND
Arctostaphylos
confertiflora
Plant
NAVARRETIA,
SPREADING
Navarretia
fossalis
Plant
NEHE
(
LIPOCHAETA
FAURIEI)
Lipochaeta
fauriei
Plant
NEHE
(
LIPOCHAETA
MICRANTHA)
Lipochaeta
micrantha
Plant
'
OHA
(
DELISSEA
RIVULARIS)
Delissea
rivularis
Plant
NOHOANU
(
GERANIUM
Geranium
multiflorum
Plant
MULTIFLORUM)

NEHE
(
LIPOCHAETA
WAIMEAENSIS)
Lipochaeta
waimeaensis
Plant
NERAUDIA
OVATA
(
NCN)
Neraudia
ovata
Plant
NERAUDIA
SERICEA
(
NCN)
Neraudia
sericea
Plant
NAVARRETIA,
FEW­
FLOWERED
Navarretia
leucocephala
ssp.
pauciflora
Plant
(=
N.
pauciflora)

MEADOWFOAM,
SEBASTOPOL
Limnanthes
vinculans
Plant
PHACELIA,
ISLAND
Phacelia
insularis
ssp.
insularis
Plant
Thursday,
June
09,
2005
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06)
    
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147
PENTACHAETA,
WHITE­
RAYED
Pentachaeta
bellidiflora
Plant
PENNY­
CRESS,
KNEELAND
PRAIRIE
Thlaspi
californicum
Plant
PAINTBRUSH,
TIBURON
Castilleja
affinis
ssp.
neglecta
Plant
PAINTBRUSH,
SOFT­
LEAVED
Castilleja
mollis
Plant
PAINTBRUSH,
GOLDEN
Castilleja
levisecta
Plant
OWL'S­
CLOVER,
FLESHY
Castilleja
campestris
ssp.
succulenta
Plant
ORCHID,
WESTERN
PRAIRIE
Platanthera
praeclara
Plant
ORCHID,
EASTERN
PRAIRIE
Platanthera
leucophaea
Plant
MONARDELLA,
WILLOWY
Monardella
linoides
ssp.
viminea
Plant
MARISCUS
PENNATIFORMIS
(
NCN)
Mariscus
pennatiformis
Plant
MINT,
LONGSPURRED
Dicerandra
cornutissima
Plant
'
OHAI
(
SESBANIA
TOMENTOSA)
Sesbania
tomentosa
Plant
MILK­
VETCH,
TRIPLE­
RIBBED
Astragalus
tricarinatus
Plant
ONION,
MUNZ'S
Allium
munzii
Plant
'
OHA
WAI
(
CLERMONTIA
Clermontia
pyrularia
Plant
MEADOWRUE,
COOLEY'S
Thalictrum
cooleyi
Plant
MILK­
VETCH,
JESUP'S
Astragalus
robbinsii
var.
jesupi
Plant
MILK­
VETCH,
COASTAL
DUNES
Astragalus
tener
var.
titi
Plant
MILK­
VETCH,
COACHELLA
VALLEY
Astragalus
lentiginosus
var.
coachellae
Plant
MILK­
VETCH,
CLARA
HUNT'S
Astragalus
clarianus
Plant
'
OLULU
(
BRIGHAMIA
INSIGNIS)
Brighamia
insignis
Plant
MEHAMEHAME
(
FLUEGGEA
Flueggea
neowawraea
Plant
NEOWAWRAEA)

LIZARD,
ISLAND
NIGHT
Xantusia
riversiana
Reptile
TURTLE,
YELLOW­
BLOTCHED
MAP
Graptemys
flavimaculata
Reptile
TURTLE,
RINGED
SAWBACK
Graptemys
oculifera
Reptile
TURTLE,
PLYMOUTH
RED­
BELLIED
Pseudemys
rubriventris
bangsi
Reptile
TURTLE,
OLIVE
(
PACIFIC)
RIDLEY
Lepidochelys
olivacea
Reptile
TORTOISE,
DESERT
Gopherus
agassizii
Reptile
LIZARD,
BLUNT­
NOSED
LEOPARD
Gambelia
silus
Reptile
SNAKE,
SAN
FRANCISCO
GARTER
Thamnophis
sirtalis
tetrataenia
Reptile
TURTLE,
LOGGERHEAD
SEA
Caretta
caretta
Reptile
SNAKE,
GIANT
GARTER
Thamnophis
gigas
Reptile
SNAKE,
EASTERN
INDIGO
Drymarchon
corais
couperi
Reptile
SKINK,
BLUE­
TAILED
MOLE
Eumeces
egregius
lividus
Reptile
LIZARD,
COACHELLA
VALLEY
Uma
inornata
Reptile
FRINGE­
TOED
SKINK,
SAND
Neoseps
reynoldsi
Reptile
TORTOISE,
GOPHER
Gopherus
polyphemus
Reptile
TURTLE,
ALABAMA
RED­
BELLIED
Pseudemys
alabamensis
Reptile
Thursday,
June
09,
2005
Page
19
of
20
(
Phase
III
3/
07/
06)
    
137
  
147
TURTLE,
FLATTENED
MUSK
Sternotherus
depressus
Reptile
TURTLE,
GREEN
SEA
Chelonia
mydas
Reptile
TURTLE,
HAWKSBILL
SEA
Eretmochelys
imbricata
Reptile
TURTLE,
LEATHERBACK
SEA
Dermochelys
coriacea
Reptile
SNAKE,
CONCHO
WATER
Nerodia
paucimaculata
Reptile
SNAIL,
NEWCOMB'S
Erinna
newcombi
Snail
SNAIL,
SNAKE
RIVER
PHYSA
Physa
natricina
Snail
SNAIL,
BLISS
RAPIDS
Taylorconcha
serpenticola
Snail
SPRINGSNAIL,
IDAHO
Fontelicella
idahoensis
Snail
SNAIL,
MORRO
SHOULDERBAND
Helminthoglypta
walkeriana
Snail
SNAIL,
TULOTOMA
Tulotoma
magnifica
Snail
SPRINGSNAIL,
BRUNEAU
HOT
Pyrgulopsis
bruneauensis
Snail
ROCKSNAIL,
PLICATE
Leptoxis
plicata
Snail
ROCKSNAIL,
PAINTED
Leptoxis
taeniata
Snail
SHAGREEN,
MAGAZINE
MOUNTAIN
Mesodon
magazinensis
Snail
No
species
were
excluded.

Thursday,
June
09,
2005
Page
20
of
20
(
Phase
III
3/
07/
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138
  
147
APPENDIX
J:
MCPA/
MCPB
Calculations
Acute
to
Chronic
Ratio
Aquatic
Organisms
(
Phase
III
3/
07/
06)
    
139
  
147
Summary
of
endpoints
(
LC50
or
EC50,
mg
ae/
L)
for
MCPA
acute
and
chronic
aquatic
toxicity
studies
ORGANISM
GROUP
MCPA
(
acute)
MCPB
(
acute
)
MCPA
(
chroni
c)
MCPB
(
chronic
)

freshwater
fish
(
rainbow
trout)
96
(
MCPA
DMAS)
3.9
No
data
No
data
freshwater
fish
(
fathead
minnow)
only
chronic
freshwater
fish
study
for
MCPA
No
data
No
data
12
No
data
freshwater
inverts
(
Daphnid)
only
one
study
chronic
freshwater
invertebrate
study
for
MCPA
82
(
MCPA
DMAS)
50
11
No
data
estuarine/
marine
fish
Atlantic
Silverside
179
(
MCPA
Acid)
No
data
No
data
No
data
estuarine/
marine
inverts
eastern
oyster
4.9
(
MCPA
sodium
salt)
No
data
No
data
No
data
Summary
of
endpoints
(
LC50
or
EC50,
mg
ae/
L)
determined
by
acute
and
chronic
ratios
ORGANISM
GROUP
MCPB
(
acute)
MCPB
(
chronic
)

freshwater
fish
3.9
.5
a
Acute
to
chronic
ratio
freshwater
inverts
50
6.7b
Acute
to
chronic
ratio
estuarine/
marine
fish
7.3c
Acute
to
chronic
.9d
Acute
to
chronic
estuarine/
marine
invert
2.9e
Freshwate
r/
estuarin
e
marine
ratio
.4f
aMCPB
Freshwater
fish
(
chronic)
.5=
[
12(
chronic
freshwater
fish
MCPA
)
/
96(
acute
freshwater
fish
MCPA)]
x3.9(
acute
freshwater
fish
MCPB)
b
MCPB
Freshwater
invertebrate
(
chronic)
6.7=[
11(
chronic
freshwater
invertebrate
MCPA
)
/
96(
acute
freshwater
invertebrate
MCPA)]
x
50(
acute
freshwater
invertebrate
MCPB)
cMCPB
Estuarine
marine
fish
(
acute)
7.3=[
96(
acute
freshwater
fish
MCPA
)
/
179(
acute
estuarine
marine
fish
MCPA)]
x
3.9(
acute
freshwater
fish
MCPB)
(
Phase
III
3/
07/
06)
    
140
  
147
dMCPB
Estuarine
marine
fish
(
chronic)
.9=(.
5
chronic
freshwater
fish
MCPB
)
/
3.9(
acute
freshwater
fish
MCPB)]
x
7.3(
acute
estuarine
marine
fish
MCPB)
eMCPB
Estuarine
marine
invertebrates
(
acute)
2.9=[
50(
acute
freshwater
invertebrate
MCPB
)
/
82(
acute
freshwater
invertebrates
MCPA)]
x
4.9(
acute
estuarine
marine
invertebrates
MCPA)
FMCPB
Estuarine
marine
invertebrates
(
chronic)
.4
=[
50(
acute
freshwater
invertebrate
MCPB
)
/
82(
acute
freshwater
invertebrates
MCPA)]
x
4.9(
acute
estuarine
marine
invertebrates
MCPA)
x[
11(
chronic
freshwater
invertebrate
MCPA
)
/
82(
acute
freshwater
invertebrates
MCPA)]
(
Phase
III
3/
07/
06)
    
141
  
147
Summarized
Chronic
Aquatic
Organism
Risk
Quotients
for
MCPB
Acid
a,
b
Application/
Scenario
Freshwater
Fishc,
d
Freshwater
Invertebrates
e,
f
Estuarine
Fishc,
d
Estuarine
Invertebrates
e,
f
Peas
(
ground
spray
application)
Oregon
0.06
<.
01
0.03
0.07
Peas
(
aerial
spray
application)
Oregon
0.06
<.
01
0.04
0.08
Peas
(
ground
spray
application)
California
0.07
<.
01
0.04
0.10
Peas
(
aerial
spray
application)
California
0.07
<.
01
0.04
0.10
a
Detailed
calculations
of
PRZM
3.12/
EXAMS
2.98
modeling
for
peas
grown
in
Oregon
and
California
are
provided
in
Appendix
B.

bChronic
toxicity
thresholds
(
LC50
or
EC50)
calculated
by
acute
to
chronic
ratio
with
values
from
MCPA
were
.5
and
6.7
mg
ae/
L
for
freshwater
fish
and
freshwater
invertebrates,
respectively.
Chronic
toxicity
thresholds
(
LC50
or
EC50)
calculated
by
acute
to
chronic
ratio
with
values
from
MCPA
were
.9
and
.4
mg
ae/
L
for
estuarine
marine
fish
and
estuarine
marine
invertebrates,
respectively.

Chronic
Fish
C
EECs
for
Oregon
bean
Scenario
were
28.1
and
31.5
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.
DEECs
for
California
lettuce
Scenario
were
36.4
and
38.9
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.

Chronic
Invertebrates
eEECs
for
Oregon
bean
Scenario
were
29.0
and
32.5
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.
FEECs
for
California
lettuce
Scenario
were
39.0
and
41.7
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.

Summarized
Acute
Aquatic
Organism
Risk
Quotients
for
MCPB
Acid
a,
b
Application/
Scenario
Freshwater
Fisha,
b
Freshwater
Invertebrates
a,
b
Estuarine
Fisha,
b
Estuarine
Invertebrates
a,
b
Peas
(
ground
spray
application)
Oregon
<
0.01
<
0.01
<
0.01
0.07
Peas
(
aerial
spray
application)
Oregon
<
0.01
<
0.01
<
0.01
0.08
Peas
(
ground
spray
application)
California
0.01
<
0.01
<
0.01
0.10
Peas
(
aerial
spray
application)
California
0.01
<
0.01
<
0.01
0.10
For
an
estuarine
marine
and
freshwater
ratio
MCPB
and
MCPA:
Acute
toxicity
thresholds
(
LC50
or
EC50)
calculated
with
acute
estuarine
marine
fish
and
estuarine
invertebrate
values
from
MCPA
179
and
4.9
respectively;
Values
from
MCPB
were
3.9
and
50
mg
ae/
L
for
acute
freshwater
fish
and
freshwater
invertebrates,
respectively.

Acute
Fish
and
Invertebrates
a
EECs
for
Oregon
bean
Scenario
were
29.5
and
33.1
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.
BEECs
for
California
lettuce
Scenario
were
40.4
and
43.2
µ
g/
L
for
ground
spray
and
aerial
spray,
respectively.
