­

1
­

UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
PC
Code
No.
129111
DP
Barcode:
D330783
Date:
July
28,
2006
MEMORANDUM
SUBJECT:
EFED
Drinking
Water
Assessment
for
the
IR­
4
Tolerance
Petition
for
Use
of
Kresoxim
Methyl
on
Curcurbit
Vegetables
[
Second
revision]

TO:
Tamue
Gibson,
Risk
Manager
Reviewer
Mary
Waller,
Risk
Manager
Registration
Division
Sara
Levy,
Chemist
Health
Effects
Division
FROM:
Cheryl
A.
Sutton,
Ph.
D.,
Environmental
Scientist
Roxolana
Kashuba,
Environmental
Scientist
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
(
7507C)

REVIEWED
BY:
R.
David
Jones,
Ph.
D.
Senior
Agronomist
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
(
7507C)

APPROVED
BY:
Elizabeth
Behl,
Branch
Chief
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
(
7507C)

The
Environmental
Fate
and
Effects
Division
(
EFED)
has
completed
its
drinking
water
assessment
[
second
revision]
in
support
of
the
IR­
4
tolerance
petition
for
the
use
of
kresoxim
methyl
(
Sovran
®
Fungicide:
50.0%
active
ingredient
by
mass;
PC
Code
129111)
as
a
wettable
granule
fungicide
on
cucurbit
vegetables
to
control
gummy
stem
blight
(
Didymella
bryoniae)
or
powdery
mildew
(
Sphaerotheca
fulginea,
Erysiphe
cichoracearum).
Sovran
®
is
proposed
for
use
as
ground
and
aerial
sprays
as
well
as
through
irrigation
systems.
The
proposed
application
rate
is
0.15
lb
ai/
A/
application
(
4.8
oz
Sovran
®
/
A,
by
mass),
with
up
to
4
applications
a
season,
for
a
total
maximum
seasonal
rate
of
0.6
lb
ai/
A
(
19.2
oz
Sovran
®
/
A,
by
mass).
[
The
first
revision
of
this
drinking
water
assessment
(
D326550)
was
conducted
using
unrevised
label
rates
of
0.2
lb
ai/
A/
application.
RD
has
since
submitted
EFED
a
revised
label.]
Generally,
cucurbits
such
as
field
cucumbers
are
planted
twice
a
year,
once
in
spring
and
once
in
the
fall,
and,
thus,
have
two
seasons
per
year.
For
the
purposes
of
determining
Estimated
Drinking
Water
Concentrations
(
EDWC),
EFED
assumes
that
the
label
rate
expressed
in
terms
of
"
per
season"
results
in
two
sets
of
(
four)
applications
per
year
(
for
a
total
of
eight
applications
per
year),
as,
in
some
locations,
there
may
be
two
growing
seasons
per
year
for
cucurbit
vegetables.
Therefore,
the
modeling
scenario
used
to
determine
EDWCs
for
this
assessment
simulates
the
use
of
kresoxim
methyl
on
two
crops
of
a
specific
­

2
­

cucurbit
vegetable
(
both
a
spring
planting
and
a
fall
planting)
at
a
single
site
for
a
total
maximum
yearly
rate
of
1.2
lb
ai/
A
(
38.4
oz
Sovran
®
/
A,
by
mass).

The
"
EFED
Risk
Assessment
for
the
Section
3
Registration
of
Kresoxim
Methyl
on
Apples,
Grapes,
and
Pecans"
(
DP
Barcodes
D244862,
D248122,
D248123,
D248359,
D245119,
D246782,
D246987,
D250295)
was
completed
in
1999.
In
the
Section
3
chapter,
EFED
stated
that:

"
Based
on
the
environmental
fate
properties
for
kresoxim
methyl,
with
consideration
of
the
product
formulation
and
application
rates,
EFED
believes
that
the
rapidly
degraded
parent
compound
is
unlikely
to
have
adverse
effects
on
the
environment.
However,
since
the
major
acid
degradate
(
BF
490­
1)
has
the
physical/
chemical
characteristics
in
common
with
those
pesticides
that
are
known
to
leach
to
ground
water
or
to
move
offsite
to
surface
water,
the
potential
for
BF
490­
1
to
reach
ground
water
and
surface
water
exists,
especially
when
it
is
applied
to
fields
with
one
or
more
of
the
following
characteristics:
alkaline
soils,
low
organic
matter,
high
sand,
shallow
ground
water
table,
and
nearby
bodies
of
water."

Thus,
this
current
assessment
includes
both
the
parent
and
the
major
degradate
BF­
490­
1.
To
model
concentrations
of
BF
490­
1,
full
conversion
to
the
degradate
from
the
rapidly
degrading
parent
compound
was
assumed.
Also,
as
stated
by
EFED
in
the
Section
3
chapter,
"
Because
of
the
concerns
raised
by
HED
with
regard
to
cancer
risk
to
mammals,
a
tier
II
drinking
water
assessment
was
conducted."
No
monitoring
data
are
available.

Although
the
proposed
rates
are
less
than
the
rate
modeled
previously,
new
Tier
II
EDWCs
were
estimated
because
the
initial
risk
assessment
was
conducted
based
on
a
ground
spray
application
and
the
proposed
new
use
includes
aerial
spray
applications.
Also,
the
newer
values
are
based
on
input
parameter
guidance
for
Tier
II
modeling
that
was
developed
in
2002.
Finally,
based
on
new
use­
related
information
from
the
Biological
and
Economic
Analysis
Division
(
BEAD),
two
seasons
of
cucurbits
per
year
are
modeled
in
this
assessment.
Previously,
only
one
season
per
year
was
modeled.
The
groundwater
EDWCs
are
approximately
1.5X
higher
than
those
in
the
previous
assessment
done
for
apples,
grapes
and
pecans.
In
the
previous
assessment,
the
groundwater
concentration
values
reported
for
use
in
the
human
health
risk
assessment
were
2.57x10­
4
µ
g/
L
for
parent
kresoxim
methyl
and
4.2
µ
g/
L
for
BF
490­
1.
The
surface
water
EDWCs
are
approximately
3­
10X
higher
for
acute
and
2­
20X
higher
for
chronic
than
those
in
the
previous
assessment
done
for
apples,
grapes
and
pecans.
In
the
previous
assessment,
the
surface
water
concentration
values
reported
for
use
in
the
acute
human
health
risk
assessment
were
1.2
µ
g/
L
for
parent
kresoxim
methyl
and
13.8
µ
g/
L
for
BF
490­
1.
The
surface
water
values
for
the
chronic
and
cancer
human
health
risk
assessments
were
reported
in
the
previous
assessment
as
the
"
long
term
average
values
of
5.8
ng/
L
for
parent
kresoxim
methyl
and
5.0
µ
g/
L
for
BF
490­
1."
New
Tier
II
values
for
the
proposed
use
of
kresoxim
methyl
on
curcurbit
vegetables
are
reported
below
in
Table
1.
The
input
parameter
values
used
in
Tier
I
modeling
(
SCI­
GROW2)
to
determine
the
groundwater
EDWC
and
in
Tier
II
modeling
(
PRZM/
EXAMS)
to
determine
the
surface
water
EDWCs
are
presented
in
Tables
2
and
3,
respectively.
The
source
environmental
fate
and
physical/
chemical
property
data
are
presented
in
Appendix
A.
Output
files
for
Tier
I
modeling
are
presented
in
Appendix
B.
Input
and
output
files
for
Tier
II
modeling
are
presented
in
129111
D330783
DWA.
zip,
as
follows:

Parent
input 
KresoximMethyl.
pzr
(
file
dated
07/
17/
2006)
Degradate
input 
BF490­
1deg.
pzr
(
file
dated
07/
17/
2006)
Parent
and
degradate
output 
129111
D330783
DWA
output.
doc
(
file
dated
07/
17/
2006)
Parent
and
degradate
time
series 
129111
D330783
DWA
time
series.
xls
(
file
dated
07/
17/
2006)
­

3
­

In
determining
EDWCs
for
drinking
water
exposure
assessment,
EFED
utilizes
a
standard
EXAMS
scenario
referred
to
as
the
"
index
reservoir"
in
Tier
II
modeling
with
PRZM
(
v.
3.12
beta;
input
generated
by
PE4VO1.
pl,
dated
8/
8/
03)
and
EXAMS
(
2.98.04).
Scenarios
simulate
a
173­
hectare
watershed
draining
into
a
5.3­
hectare
flow­
through
reservoir
that
is
2.3­
meters.
The
reservoir
serves
as
a
surrogate
for
a
variety
of
small
water
bodies
used
for
drinking
water.
It
is
assumed
that
runoff
is
equally
likely
to
flow
into
the
reservoir
from
all
areas
of
the
treated
field,
and
the
applied
Percent
Crop
Area
(
PCA)
accounts
for
the
portion
of
the
watershed
that
is
cropped
and
treated.
Additional
information
on
the
models
PRZM
and
EXAMS
can
be
located
at:
http://
www.
epa.
gov/
oppefed1/
models/
water/.

The
standard
PRZM/
EXAMS
scenario
selected
for
modeling
is
Florida
cucumbers,
modified
for
two
seasons
per
year.
The
standard
Florida
cucumbers
scenario
represents
one
fall
season
of
cucumbers
per
year,
with
emergence
date
of
10/
10/
61,
maturation
date
of
12/
05/
61,
and
harvest
date
of
12/
10/
61.
A
spring
season
of
cucumbers
was
added
to
the
modified
scenario
with
emergence
date
of
04/
10/
61,
maturation
date
of
06/
05/
61,
and
harvest
date
of
06/
10/
61
(
Record
11).
The
number
of
different
crops
(
NDC)
in
the
simulation
(
Record
8)
was
changed
from
1
to
2.
Additionally,
to
adjust
runoff
parameters
associated
with
cropped
land
for
the
spring
season,
RUSLE
numbers
(
Record
9C)
for
dates
(
format
MM/
DD)
01/
04,
16/
04,
01/
05,
15/
05,
16/
05,
25/
05,
01/
06,
and
16/
06
were
changed
from
0.881,
0.881,
0.880,
0.836,
0.849,
0.938,
0.840,
and
0.572
to
0.636,
0.683,
0.715,
0.743,
0.768,
and
0.793,
respectively.
Record
9
was
repeated
twice
(
ie.,
NDC
times).
The
modified
scenario,
FLcucumberCnew.
txt
(
file
dated
07/
05/
2006),
can
be
found
in
129111
D330783
DWA.
zip.
The
use
scenario
reflects
twice
the
proposed
maximum
seasonal
application
rate
on
the
label.
An
aerial
use
is
selected
over
a
ground
spray
use
to
maximize
potential
spray
drift
to
surface
water
bodies.
Application
dates
are
chosen
based
on
label
information,
as
well
as
on
crop­
specific
information
presented
in
EFED's
PRZM/
EXAMS
standard
scenario
metadata
files
and
the
USDA
agricultural
crop
profiles
(
www.
pestdata.
ncsu.
edu/
cropprofiles).
This
scenario
was
chosen
as
it
is
expected
to
be
more
vulnerable
than
most
areas
in
the
US
used
to
grow
cucurbits
A
default
PCA
of
0.87
is
used
for
this
assessment
as
there
is
no
crop
specific
PCA
for
cucumbers.

Chemical
property
input
values
are
chosen
according
to
the
current
EFED
standard
guidance
document
(
Input
Parameters
in
Modeling
the
Environmental
Fate
and
Transport
of
Pesticides,
Version
II,
February
28,
2002).
Per
this
guidance,
the
Koc
of
the
parent
input
value
and
the
Koc
of
the
degradate
input
value
for
PRZM­
EXAMS
surface
water
modeling
are
each
the
mean
of
4
values
in
four
different
soils.
As
there
was
only
a
single
aerobic
soil
metabolism
measurement
available
each
for
parent
and
degradate,
the
aerobic
soil
metabolism
input
values
are
these
single
half­
lives
multiplied
by
3
to
account
for
uncertainty.
The
aerobic
aquatic
metabolism
input
value
for
parent
is
the
90th
percentile
value
on
the
mean
of
2
values.
The
aerobic
aquatic
metabolism
input
value
for
the
degradate
is
assumed
stable
(
as
the
two
available
halflives
are
reported
only
as
>>
100
days).
[
The
aerobic
aquatic
metabolism
degradate
input
value
has
been
changed
from
the
input
value
used
in
previous
kresoxim­
methyl
assessments
(
300
days).
The
assumption
of
degradate
stability
to
aerobic
aquatic
metabolism,
however,
only
increased
surface
water
drinking
water
concentrations
by
1­
23%.
For
chemicals
with
half­
lives
longer
than
the
reservoir
turnover
rate
(
approximately
three
times
a
year),
reservoir
turnover
decreases
DWECs
via
dissipation
more
than
degradation
decreases
DWECs.
The
assumption
of
degradate
stability
to
aerobic
aquatic
metabolism
was
made
after
the
kresoxim­
methyl
cucurbits
ecological
exposure
assessment
(
D326550)
was
completed.
Therefore,
environmental
surface
water
concentrations
used
in
the
kresoxim­
methyl
cucurbits
ecological
exposure
assessment
are
calculated
using
the
degradate
aerobic
aquatic
metabolism
input
value
of
300
days.]
The
anaerobic
aquatic
metabolism
input
value
for
parent
is
the
90th
percentile
value
on
the
mean
of
2
values.
In
the
absence
of
data,
it
is
assumed
that
the
degradate
is
stable
to
anaerobic
aquatic
metabolism.

For
further
details
on
the
environmental
fate
of
kresoxim
methyl
and
its
acid
degradate
BF
490­
1,
please
see
the
complete
risk
assessment.
If
additional
refinements
of
this
new
use
drinking
water
assessment
are
requested,
please
notify
Cheryl
Sutton
(
308­
6168)
or
Betsy
Behl
(
308­
6128).
­

4
­

Table
1.
EDWCs
for
the
drinking
water
assessment
based
on
the
aerial
application
of
kresoxim
methyl
to
cucurbits
at
the
maximum
annual
rate
of
1.2
lb
ai/
A
(
0.6
lb
ai/
A
per
season
for
two
seasons).

Surface
water
drinking
water
sources
Parent
Acute
1­
in­
10
year
peak
:
11.7
µ
g/
L
(
ppb)
1
Chronic
1­
in­
10­
year
annual
mean:
0.11
µ
g/
L
(
ppb)
30­
year
mean:
0.07
µ
g/
L
(
ppb)
BF
490­
1
Acute
1­
in­
10
year
peak:
46.3
µ
g/
L
(
ppb)
1
Chronic:
1­
in­
10­
year
annual
mean:
14.8
µ
g/
L
(
ppb)
30­
year
mean:
7.81
µ
g/
L
(
ppb)

Groundwater
drinking
water
sources
3.85
x
10­
4
µ
g/
L
(
ppb)
6.27
µ
g/
L
(
ppb)

1All
surface
water
values
are
corrected
for
the
national
default
percent
crop
area
(
PCA)
factor
of
0.87.

Table
2.
SCI­
GROW2
input
parameter
values
kresoxim
methyl
applied
to
cucurbits.
Parameter
Value
Source/
Comment
Maximum
Application
Rate
(
lb
a.
i./
A/
application)
0.15
lb
ai/
A/
application
Label
Maximum
Number
of
Applications
per
Year
8
Label
Aerobic
Soil
Metabolism
Half­
life
(
days)
<
1
(
parent)

131
(
BF
490­
1)
MRIDs
43864269,
43864270,
43864271
Organic
Carbon
Partition
Coefficient
(
Koc;
mL/
g)
431
(
parent)

44
(
BF
490­
1)
MRID
43864276;
input
value
represents
the
median
of
four
values
MRID
44341034;
input
value
is
the
median
of
three
values
­

5
­

Table
3.
PRZM/
EXAMS
input
parameter
values
for
the
drinking
water
assessment
for
kresoxim
methyl
applied
to
cucumbers
in
Florida
by
aerial
spray.
Parameter
Value
Source/
Comment
Application
Rate
0.15
lb
ai/
A/
application
(
0.168
kg
ai/
ha/
application)
Label.

Number
of
Applications
4
per
season
(
8
per
year)
Label
and
BEAD
personal
communication
(
6/
29/
2006).

Date
of
First
Application
May
1
USDA
Crop
Profiles
Information.

Interval
Between
Apps.
(
days)
7
w/
n
season;
160
b/
w
seasons
Label.

Organic
Carbon­
Normalized
Soil
Partition
Coefficient
(
Koc;
mL/
g)
419
(
parent)

49
(
BF
490­
1)
MRID
43864276;
input
value
is
mean
of
4
values
(
parent),
MRID
44341034;
input
value
is
mean
of
3
values
(
degradate).

Aerobic
Soil
Metabolism
Halflife
(
days)
3
(
parent)

393
(
BF
490­
1)
MRIDs
43864269,
43864270,
43864271;
input
values
are
single
half­
lives
multiplied
by
3.

Spray
Drift
Fraction
(
aerial
spray)
0.16
EFED
Input
Parameter
Guidance.

Application
Efficiency
(
aerial
spray)
0.95
EFED
Input
Parameter
Guidance.

Percent
Cropped
Area
0.87
EFED
Input
Parameter
Guidance.

Molecular
Weight
313.4
(
parent)
299.3
(
BF
490­
1)
Phys/
chem.
property
data
(
Section
3).

Solubility
in
Water
(
ppm;
@
20
C)
2
(
parent)

3661
(
BF
490­
1)
Phys/
chem.
property
data
(
Section
3).

Estimated
based
on
Koc
Vapor
Pressure
(@
20
C)
1.7x10­
9
torr
(
parent)
Phys/
chem.
property
data
(
Section
3);
parent
data
used
as
default
for
degradate.

Henry's
Law
Constant
3.5x10­
10
atm
m3/
mol
(
parent)
Phys/
chem.
property
data
(
Section
3);
parent
data
used
as
default
for
degradate.

Aerobic
Aquatic
Metabolism
Half­
life
(
days)
1.4
(
parent)

stable
(
BF
490­
1)
MRID
43864273;
input
value
is
90th
percentile
value
on
the
mean
of
2
values
(
parent);
assumed
stability
(
degradate).

Anaerobic
Aquatic
Metabolism
Half­
life
(
days)
1.7
(
parent)

stable
(
BF
490­
1)
MRID
43864272;
input
values
are
90th
percentile
value
on
mean
of
2
values
(
parent);
assumed
stability
(
degradate).

Hydrolysis
Half­
life
@
pH
5
=
stable
(
parent)

@
pH
7
=
34
days
(
parent)

@
pH
9
=
7
hours
(
parent)

@
pH
5,
7,
9
=
stable
(
BF
490­
1)
MRID
43864268.

Aquatic
Photolysis
Half­
life
@
pH
5
(
days)
29.8
(
parent)

stable
(
BF
490­
1)
MRID
44341031.
­

6
­

APPENDIX
A
PHYSICAL
AND
CHEMICAL
PROPERTY
VALUES
FOR
KRESOXIM
METHYL
AND
BF
490­
1
Parameter
Value
Source/
Comment
Molecular
Weight
313.4
(
parent)

299.3
(
BF
490­
1)
Phys/
chem.
property
data
(
Section
3)

Solubility
in
Water
(
ppm;
@
20
C)
2
(
parent)

3661
(
BF
490­
1)
Phys/
chem.
property
data
(
Section
3)

Estimated
based
on
Koc
Vapor
Pressure
(@
20
C)
1.7x10­
9
torr
(
parent)
Phys/
chem.
property
data
(
Section
3)

Henry's
Law
Constant
3.5x10­
10
atm
m3/
mol
(
parent)
Phys/
chem.
property
data
(
Section
3)

Hydrolysis
Half­
life
@
pH
5
=
stable
(
parent)

@
pH
7
=
34
days
(
parent)

@
pH
9
=
7
hours
(
parent)

@
pH
5,
7,
9
=
stable
(
BF
490­
1)
MRID
43864268
Aquatic
Photolysis
Half­
life
@
pH
5
(
days)
29.8
(
parent)

stable
(
BF
490­
1)
MRID
44341031
Soil
Photolysis
Half­
life
(
days)
70.4
(
parent)

stable
(
BF
490­
1)
MRID
44341033
Soil
Partition
Coefficient
(
Kd;
mL/
g)
0.93,
3.45,
6.49,
10.52
(
parent)

0.44,
0.79,
0.87
(
BF
490­
1)
MRID
43864276
MRID
44341034
Organic
Carbon­
Normalized
Soil
Partition
Coefficient
(
Koc;
mL/
g)
249,
320,
541,
567
(
parent)

33,
44,
69
(
BF
490­
1)
MRID
43864276
MRID
44341034
Aerobic
Soil
Metabolism
Half­
life
(
days)
<
1
(
parent)

131
(
BF
490­
1)
MRIDs
43864269,
43864270,
43864271
Anaerobic
Aquatic
Metabolism
Half­
life
(
days)
0.9,
1.3
(
parent)
MRID
43864272
Aerobic
Aquatic
Metabolism
Half­
life
(
days)
1.2,
1.3
(
parent)

>>
100
(
BF
490­
1)
MRID
43864273
BCF
in
Fish
220X
MRID
44341037
­

7
­

APPENDIX
B
SCI­
GROW2
MODELING
OUTPUT
FILES
1)
Kresoxim
Methyl
EDWC
SCIGROW
VERSION
2.3
ENVIRONMENTAL
FATE
AND
EFFECTS
DIVISION
OFFICE
OF
PESTICIDE
PROGRAMS
U.
S.
ENVIRONMENTAL
PROTECTION
AGENCY
SCREENING
MODEL
FOR
AQUATIC
PESTICIDE
EXPOSURE
SciGrow
version
2.3
chemical:
Kresoxim­
methyl
time
is
6/
29/
2006
10:
52:
22
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
Application
Number
of
Total
Use
Koc
Soil
Aerobic
rate
(
lb/
acre)
applications
(
lb/
acre/
yr)
(
ml/
g)
metabolism
(
days)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
0.150
8.0
1.200
4.31E+
02
1.0
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
groundwater
screening
conc
(
ppb)
=
3.85E­
04
**
See
note
below.
************************************************************************
**
Values
below
0.006
ppb
(
6
ng/
L)
are
beyond
the
scope
of
the
regression
data
in
SCIGROW
2.3
and
have
not
been
verified.
If
concerns
are
raised
by
exposures
of
less
than
0.006
ppb,
a
higher_
tier
ground_
water
exposure
assessment
should
be
considered,
regardless
of
how
low
a
screening
concentration
is
returned
by
SCIGROW.

2)
BF
490­
1
EDWC
SCIGROW
VERSION
2.3
ENVIRONMENTAL
FATE
AND
EFFECTS
DIVISION
OFFICE
OF
PESTICIDE
PROGRAMS
U.
S.
ENVIRONMENTAL
PROTECTION
AGENCY
SCREENING
MODEL
FOR
AQUATIC
PESTICIDE
EXPOSURE
SciGrow
version
2.3
chemical:
BF
490­
1
time
is
6/
29/
2006
10:
51:
46
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
Application
Number
of
Total
Use
Koc
Soil
Aerobic
rate
(
lb/
acre)
applications
(
lb/
acre/
yr)
(
ml/
g)
metabolism
(
days)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
0.150
8.0
1.200
4.40E+
01
131.0
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
groundwater
screening
conc
(
ppb)
=
6.27E+
00
************************************************************************
