­

1
­

UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
PC
Code
No.
055459
DP
Barcode:
D314492
D321332
D321334
Date:
March
23,
2006
MEMORANDUM
SUBJECT:
EFED
Drinking
Water
Assessment
for
the
IR­
4
Tolerance
Petition
for
Use
of
Quinoxyfen
on
Lettuce,
Strawberries,
Melons,
Peppers
(
Bell
and
Non­
bell),
and
Eggplants
TO:
Sidney
Jackson,
Risk
Manager
Reviewer
Daniel
Rosenblatt,
Risk
Manager
Registration
Division
FROM:
Cheryl
A.
Sutton,
Ph.
D.,
Environmental
Scientist
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
in
support
of
the
IR­
4
tolerance
petition
for
the
use
of
quinoxyfen
(
Quintec
7
22.58%
active
ingredient;
2.08
lb
ai/
gal.;
PC
Code
055459)
as
a
fungicide
on
lettuce,
strawberries,
melons,
peppers
(
bell
and
non­
bell),
and
eggplant
to
control
powdery
mildew
(
Erysiphe
cichoracearum,
Sphaerotheca
macularis,
Sphaerotheca
fuliginea,
or
Leveillula
taurica
).
Quinoxyfen
is
proposed
for
use
as
a
ground
spray/
foliar
application
with
up
to
4
applications
of
0.097
lbs
a.
i./
A
(
6
oz.
Quintec)
with
a
10­
day
minimum
re­
application
interval,
for
a
maximum
total
application
rate
of
0.39
lbs
a.
i./
A/
crop
(
24
oz.
Quintec).
For
the
purposes
of
determining
EDWC's,
EFED
has
made
the
assumption
that
the
label
rate
expressed
in
terms
of
"
per
crop"
is
synonymous
with
an
annual
rate.
The
use
of
quinoxyfen
on
multiple
crops
of
lettuce
or
other
agricultural
commodity
at
a
single
site
during
the
year
may
require
an
additional
assessment.

The
A
EFED
Risk
Assessment
for
the
Section
3
Registration
of
Quinoxyfen
@

(
DP
Barcodes:
D278515,
D285770,
D286376)
was
completed
in
August
2003;
uses
included
in
the
assessment
were
grapes,
hops
and
cherries.
In
that
assessment,
estimated
drinking
water
concentrations
(
EDWC)
for
use
in
the
human
health
risk
assessment
were
determined
using
a
maximum
annual
application
rate
for
cherries
of
0.55
lb
a.
i./
A
(
five
­

2
­

applications
of
0.114
lb
a.
i./
A/
application).
Because
the
label
did
not
provide
for
a
minimum
application
interval
at
the
time
the
assessment
was
conducted,
a
default
of
1
day
was
utilized.

Because
maximum
application
rates
for
the
proposed
uses
on
lettuce,
strawberries,
melons,
peppers,
and
eggplants
do
not
exceed
the
previous
maximum
application
rate
for
any
crop,
and
because
the
previous
HED
assessment
indicated
that
the
previously
estimated
drinking
water
levels
(
at
a
higher
application
rate
and
shorter
re­
application
interval)
were
not
a
concern,
the
EDWC
=

s
generated
for
the
Section
3
Risk
Assessment
(
dated
8/
4/
2003),
presented
below
in
Table
1,
are
still
current
and
are
recommended
for
use
in
HED
=

s
risk
assessment.
All
input
parameter
values
used
for
modeling
are
presented
below
in
Tables
2
and
3.
Other
details
of
the
Tier
I
(
used
for
groundwater)
and
Tier
II
(
used
for
surface
water)
modeling
processes
can
be
located
in
the
Section
3
Risk
Assessment.
For
further
details
on
the
environmental
fate
of
quinoxyfen,
please
see
the
complete
risk
assessment.
If
additional
refinements
of
this
new
use
drinking
water
assessment
are
requested,
please
notify
EFED.

Table
1.
EDWC's
for
the
drinking
water
assessment
based
on
quinoxyfen
use
on
cherries.

Surface
water
drinking
water
sources
acute:
13.34
ug/
L
(
ppb)
1
1­
in­
10­
years
(
chronic):
8.35
ug/
L
(
ppb)
30­
year
average:
5.95
ug/
L
(
ppb)
Groundwater
drinking
water
sources
0.00600
ug/
L
(
ppb)
or
6.00
ng/
L
(
parts
per
trillion)
1EDWC
values
were
generated
using
the
PRZM/
EXAMS
model
with
an
orchard
airblast
spray
to
cherries
in
Michigan
application
scenario
which
represents
the
highest
annual
application
rate
among
the
registered
uses.

Table
2.
SCI­
GROW2
input
parameter
values
for
quinoxyfen
applied
to
cherries.
Parameter
Value
Source/
Comment
Maximum
Application
Rate
(
lb
a.
i./
A/
application)
0.11375
1
label
Maximum
Number
of
Applications
per
Year
5
label
Aerobic
Soil
Metabolism
Half­
life
(
days)
465.5
Represents
the
median
value
of
eight
values
ranging
from
210
to
648,
based
on
concentration
data
for
the
parent
plus
3­
OH
quinoxyfen.
MRIDs
45360626
&
45360627
Organic
Carbon
Partition
Coefficient
(
Koc)
18339
Represents
the
lowest
value
of
eight
values
ranging
from
18339
to
75930
for
the
parent
compound
only.
MRID
45360703
1Numbers
were
generated
using
the
SCI­
GROW2
model
with
a
cherries
application
scenario
which
represents
the
highest
annual
application
rate
among
the
proposed
uses.
­

3
­

Table
3.
PRZM/
EXAMS
input
parameter
values
for
the
drinking
water
assessment
for
quinoxyfen
applied
to
cherries
in
Michigan
by
orchard
airblast
spray.
Parameter
Value
Source/
Comment
Application
Rate
(
lb
a.
i./
A/
application)
0.114
label
Number
of
Applications
5
label
Date
of
First
Application
May
30
USDA
Crop
Profiles
information
Interval
Between
Applications
(
days)
1
label
Soil
Partition
Coefficient
(
Kd;
mL/
g)
146
Represents
the
lowest
non­
sand
value
among
8
values
ranging
from
73
to
1803.
MRID
45360703
Aerobic
Soil
Metabolism
Half­
life
(
days)
554
Value
calculated
from
data
for
parent
plus
3­
OH
quinoxyfen.
Represents
the
90th
percentile
of
the
upper
confidence
bound
on
the
mean
of
8
half­
life
values.
MRIDs
45360626
&
45360627
Spray
Drift
Fraction
(
orchard
airblast
spray)
0.041
EFED
Input
Parameter
Guidance.

Application
Efficiency
0.95
EFED
Input
Parameter
Guidance.

Percent
Cropped
Area
0.87
EFED
Input
Parameter
Guidance.

Molecular
Weight
308.14
g/
mole
Phys/
chem.
property
data
Solubility
in
Water
(
ppm)
0.116
Phys/
chem.
property
data
Aerobic
Aquatic
Metabolism
Half­
life
(
days)
495
Input
value
was
determined
by
multiplying
the
calculated
half­
life
by
3
to
account
for
the
uncertainty
associated
with
using
a
single
value,
per
EFED
model
input
parameter
guidance.
MRID
45360630
Anaerobic
Aquatic
Metabolism
Half­
life
(
days)
2013
Due
to
its
magnitude,
the
half­
life
was
used
as
reported,
as
multiplying
it
by
3
would
not
provide
an
additional
measure
of
conservatism
nor
decrease
the
uncertainty
surrounding
its
use.
MRID
45360629
Hydrolysis
Half­
life
@
pH
7
(
days)
stable
MRID
45360620
Aquatic
Photolysis
Half­
life
@
pH
7
(
days)
1
day
Input
value
is
based
only
on
parent
data.
Separate
data
were
not
available
for
3­
OH
quinoxyfen,
and
the
degradate
was
not
detected
in
the
irradiated
test
solutions.
While
the
half­
life
was
reported
as
"<
1day,"
for
modeling,
the
input
value
is
1
day.
MRIDs
­

4
­

45360623,
45360624
As
part
of
the
current
IR­
4
drinking
water
assessment,
EFED
reviewed
four
magnitude
of
residues
studies
(
on
cantaloupe,
MRID
46612001;
lettuce,
MRID
46611501;
strawberries,
MRID
46611502;
and
peppers,
MRID
46053101).
None
of
the
four
studies
met
EFED's
criteria
for
use
of
the
results
in
estimating
a
foliar
dissipation
rate.
Some
of
the
criteria
not
met
were
that
the
entire
plant
was
not
analyzed,
data
were
not
reported
for
at
least
3
sampling
periods,
and
that
sampling
was
not
conducted
immediately
following
application
(
i.
e.,
there
were
no
time
0
samples).
