Document ID: EPA-HQ-OPP-2002-0055-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2002-06-27T04:00Z

March
6,
2002
MEMORANDUM
SUBJECT:
DISULFOTON:
Aggregate
Risk
Assessment
(February,
2002
Revision)
PC
Code:
032501
DP
Barcode:
D280669
FROM:
Christina
Jarvis,
Environmental
Protection
Specialist
Richard
Griffin,
Biologist
Reregistration
Branch
2
Health
Effects
Division
(7509C)

THROUGH:
Alan
Nielsen,
Branch
Senior
Scientist
Reregistration
Branch
2
Health
Effects
Division
(7509C)

TO:
Christina
Scheltema,
Chemical
Review
Manager
Reregistration
Branch
3
Special
Review
and
Reregistration
Division
(7508W)

**
THIS
DOCUMENT
SUPERCEDES
ALL
PREVIOUS
AGGREGATE
RISK
ASSESSMENT
DOCUMENTS**

The
Agency,
as
part
of
the
disulfoton
interim
reregistration
eligibility
decision,
is
required
by
the
Food
Quality
Protection
Act
to
ensure
"that
there
is
reasonable
certainty
that
no
harm
will
result
from
aggregate
exposure
to
pesticide
chemical
residue,
including
all
anticipated
dietary
exposures
and
other
exposures
for
which
there
is
reliable
information."

The
following
aggregate
risk
assessment
integrates
the
assessments
that
HED
has
completed
for
disulfoton
dietary
and
residential
exposure,
and
has
used
the
combined
exposure
estimates
to
evaluate
the
estimates
of
drinking
water
contamination
modeled
by
the
Environmental
Fate
and
Effects
Division
(EFED).
All
routes
of
disulfoton
exposure
have
been
2
considered
including
oral
(food
and
water
consumption),
dermal
(applying
granules
to
ornamental
plants),
and
inhalation
(also
during
application
to
ornamental
plants).
The
possibility
of
children
ingesting
treated
soil
around
ornamental
plants
has
also
been
considered
in
this
assessment.
This
aggregate
risk
assessment
also
considers
the
probable
duration(
s)
of
exposure
to
disulfoton
and
how
these
intervals
of
exposure
may
coincide.
The
intervals
of
exposure
considered
in
the
disulfoton
aggregate
risk
assessment
are
acute
(one­
day),
short­
term
(one­
day
to
one­
month),
and
chronic
(one­
year
or
more).

The
Agency
notes
that
this
assessment
may
include
uses
that
have
been
or
will
be
deleted
in
the
future
by
the
registrant,
such
as
the
homeowner
use
on
vegetable
gardens.

Aggregate
risk,
and
related
drinking
water
levels
of
comparison
(DWLOC)
estimates
have
been
made
in
accord
with
the
HED
interim
guidance
(Updated
"Interim
Guidance
for
Incorporating
Drinking
Water
Exposure
into
Aggregate
Risk
Assessments,"
8/
1/
99).

Basis
for
Revision
The
aggregate
risk
assessment
section
of
the
February
7,
2000
HED
risk
assessment
chapter
(D.
Anderson
memo,
02/
07/
00)
did
not
include
exposure
from
residential
sources,
as
exposure
from
the
residential
pathway
alone
exceeded
the
Agency's
level
of
concern.
Since
that
time,
HED
has
revised
the
residential
risk
estimates
for
disulfoton,
based
on
new
toxicity
and
exposure
data,
label
changes,
and
revisions
to
the
Residential
Standard
Operating
Procedures.
New
toxicity
and
exposure
data
were
submitted
by
the
registrant
to
support
the
currently
marketed
residential
product
(Bayer
Advanced
Garden
2­
in­
1
Systemic
Rose
and
Flower
Care®).
However,
since
other
products
marketed
by
registrants
other
than
Bayer
are
currently
available,
this
aggregate
risk
assessment
will
consider
these
products
as
well
as
the
Bayer
1%
a.
i.
product.

Dietary
risk
estimates
for
disulfoton
have
not
been
revised
for
this
aggregate
assessment.
Estimated
concentrations
of
disulfoton
in
surface
and
ground
water
are
derived
from
the
EFED
memo
dated
02/
25/
2002
(J.
Wolfe
memo,
D280670).
This
memo
differs
from
the
aggregate
risk
assessment
dated
6/
27/
2001
in
that
the
estimated
concentrations
of
disulfoton
in
drinking
water
have
been
recently
revised.

Recent
Data
Submitted
by
Bayer
Toxicity
Data:
Based
on
the
results
of
the
newly
submitted
3­
day
dermal
toxicity
study
in
rats
(MRID
45239602),
the
HED
Hazard
Identification
Assessment
Review
Committee
(HIARC)
amended
the
dose
level
used
to
estimate
risk
for
short­
term
residential
dermal
exposure.
The
dose
level
for
short­
term
dermal
risk
estimates
has
been
revised
from
0.4
mg/
kg/
day
to
0.5
mg/
kg/
day
(NOAEL)
based
on
plasma
and
brain
cholinesterase
inhibition
observed
in
female
rats
at
1.0
mg/
kg/
day
(LOAEL).
The
Agency
requires
a
margin
of
exposure
(MOE)
of
100
for
short­
term
risk
based
on
an
uncertainty
factor
of
100
(10x
for
interspecies
extrapolation
and
10x
for
intraspecies
variability).
Following
an
evaluation
of
the
disulfoton
3
toxicity
database,
the
FQPA
Safety
Factor
Committee
concluded
(1/
24/
00)
that
the
additional
safety
factor
of
10x
required
by
the
FQPA
should
be
reduced
to
1x.

Exposure
Data:
The
registrant
also
submitted
a
dermal
and
inhalation
exposure
study
(MRID
45333401)
for
the
residential
application
of
Bayer
Advanced
Garden
2­
in­
1
Systemic
Rose
and
Flower
Care®.
The
Agency
has
found
this
study
to
be
acceptable
(on
an
interim
basis
pending
clarification
of
several
issues
by
the
registrant),
and
has
used
the
results
of
the
study
to
estimate
possible
exposure
during
application.
Note
that
aggregate
risk
estimates
are
based
on
residential
dermal
exposure
only,
since
data
indicate
that
inhalation
exposure
is
negligible
(all
samples
were
either
non­
detectable
or
less
than
the
level
of
quantitation).

Exposure/
Risk
Estimates
for
Food
Uses
Disulfoton
is
currently
used
on
a
variety
of
food
crops
including
asparagus,
barley,
soybeans,
wheat,
sorghum,
potatoes,
cotton,
cabbage,
lettuce,
cole
crops,
beans,
peppers,
and
peas.
The
greatest
use,
estimated
by
the
Agency
in
lbs
a.
i.
applied
from
1987­
98,
is
on
cotton,
wheat,
potatoes,
and
peanuts.
Dietary
risk
estimates
for
disulfoton
are
based
on
residue/
usage
estimates
for
the
above
crops
and
on
the
following
dose
levels:

aPAD:
The
disulfoton
acute
population
adjusted
dose
(aPAD)
is
0.0025
mg/
kg
based
on
a
NOAEL
of
0.25
mg/
kg
and
an
uncertainty
factor
of
100
(10x
for
interspecies
extrapolation
and
10x
for
intraspecies
variability).
No
additional
FQPA
safety
factor
is
required,
based
on
a
1/
24/
00
decision
by
the
FQPA
Safety
Factor
Committee.
Toxicological
endpoints
are
signs
of
neurotoxicity,
and
plasma/
erythrocyte
cholinesterase
inhibition
in
female
rats.

cPAD:
The
disulfoton
chronic
population
adjusted
dose
(cPAD)
is
0.00013
mg/
kg/
day
based
on
a
NOAEL
of
0.013
mg/
kg/
day
and
an
uncertainty
factor
of
100
(10x
for
interspecies
extrapolation
and
10x
for
intraspecies
variability).
No
additional
FQPA
safety
factor
is
required,
based
on
a
1/
24/
00
decision
by
the
FQPA
Safety
Factor
Committee.
Toxicological
endpoints
are
depressed
plasma,
erythrocyte
and
corneal
cholinesterase
levels
in
both
sexes
and
depressed
brain
and
retinal
cholinesterase
levels
in
females.

Dietary
risk
estimates
were
completed
February
7,
2000
(W.
O.
Smith
memo
to
D.
Anderson)
and
have
not
been
revised
since
that
time.
The
dietary
risk
assessment
used
all
available
information
including
usage
data
(percent
crop
treated),
PDP
and
FDA
monitoring
data,
and
processing
data
submitted
by
the
registrant.
The
2/
7/
2000
dietary
risk
assessment
is
considered
a
refined
(tier
3)
assessment
that
cannot
be
amended
to
any
significant
degree
(unless
new
data
is
submitted).

In
the
acute
(one­
day)
dietary
exposure
analysis
the
highest
exposure
estimate
for
any
population
subgroup
is
0.000239
mg/
kg
(children
1­
6
years
old)
and
is
taken
from
the
99.9th
percentile
of
exposure
since
the
assessment
used
a
probabilistic
(Monte
Carlo)
approach.
The
exposure
estimate
for
children
(1­
6)
is
10%
of
the
disulfoton
aPAD,
or
if
expressed
as
a
margin
of
exposure;
MOE
=1,044.
The
general
U.
S.
population
is
estimated
to
be
exposed
at
the
level
of
4
0.000176
mg/
kg
(7%
of
the
aPAD).

In
the
chronic
(one­
year
to
lifetime)
dietary
exposure
analysis
the
highest
exposure
estimate
for
any
population
subgroup
is
0.000005
mg/
kg/
day
(children
1­
6
years
old).
The
exposure
estimate
for
children
(1­
6)
is
4%
of
the
disulfoton
cPAD,
or
if
expressed
as
a
margin
of
exposure;
MOE
=
2,600.
The
general
U.
S.
population
is
estimated
to
be
exposed
at
the
level
of
0.000003
mg/
kg/
day
(2%
of
the
cPAD).

Exposure/
Risk
Estimates
for
Residential
Use
Residential
exposure
scenarios
(notably
application
by
a
belly
grinder)
with
MOE
values
of
less
than
100
are
not
considered
in
the
aggregate
risk
assessment.
This
also
includes
the
use
of
disulfoton
spikes
that
cannot
be
assessed
for
potential
exposure
due
to
a
lack
of
data.

The
disulfoton
short­
term
aggregate
risk
assessment
refers
to
three
exposure
scenarios
from
the
5/
30/
01
residential
risk
assessment:
1)
an
adult
applying
a
granular
product
with
a
spoon,
measuring
scoop,
shaker
can,
or
by
hand
at
the
rate
of
0.069
lb
a.
i./
1,000
ft
2
to
vegetables,
2)
an
adult
applying
Bayer
Advanced
Garden
2­
in­
1
Systemic
Rose
and
Flower
Care®
with
a
measuring
cup/
lid
to
25
shrubs
at
the
label
rate
of
0.01
lb
a.
i./
4
ft
shrub,
and
3)
a
small
child
(toddler)
ingesting
soil
treated
with
disulfoton.
Residential
exposure
scenarios
are
expected
to
occur
within
the
short­
term
(1­
30
day)
interval.

The
dermal
exposure
estimate
for
application
to
vegetables
is
0.0034
mg/
kg/
day
(MOE
=
150)
and
represents
the
upper­
end
of
exposure
scenarios
other
than
those
with
estimated
MOEs
of
less
than
100.
The
dermal
exposure
estimate
for
applying
Bayer
Advanced
Garden
2­
in­
1
Systemic
Rose
and
Flower
Care®
to
25
shrubs
at
0.01
lb
a.
i./
4
ft.
shrub
is
0.00033
mg/
kg/
day
(MOE
=
1,500).

The
incidental
oral
exposure
estimate
for
soil
ingestion
by
a
child
following
treatment
is
0.00013
mg/
kg/
day
(MOE
=
230),
based
on
the
maximum
application
rate
of
0.3
lb
ai/
1000
ft
2
to
flowerbeds,
and
represents
the
upper­
end
of
exposure
scenarios
other
than
those
with
estimated
MOEs
of
less
than
100.
The
incidental
oral
exposure
estimate
for
soil
ingestion
by
a
child,
based
on
the
application
of
Bayer
Advanced
Garden
2­
in­
1
Systemic
Rose
and
Flower
Care®
to
flowerbeds
at
the
maximum
rate
of
0.21
lb
ai/
1000
ft
2
,
is
0.0000917
mg/
kg/
day
(MOE
=
330).

Drinking
Water
Contamination
Information
Data
indicate
that
both
parent
disulfoton
and
its
degradates
may
be
found
in
groundwater
and
surface
water.
However,
the
Agency
does
not
consider
the
available
groundwater
and
surface
water
monitoring
data
for
disulfoton
adequate
for
the
purposes
of
risk
assessment.
Instead,
estimates
of
the
potential
contamination
of
groundwater
and
surface
water
by
disulfoton
and
the
sulfone
and
sulfoxide
degradates
are
based
on
current
Agency
models,
and
are
generally
considered
a
screening
tool
rather
than
a
predictor
of
residues
in
finished
drinking
water.
5
Groundwater
estimated
drinking
water
concentrations
(EDWCs)
for
total
disulfoton
residues
(parent
plus
the
sulfoxide
and
sulfone
degradates)
were
calculated
using
the
Agency's
SCI­
GROW
screening
model.
Using
a
scenario
where
disulfoton
was
applied
to
cotton
once
per
season
at
the
maximum
use
rate
of
3
lb
a.
i./
A,
the
maximum
concentration
of
total
residues
in
ground
water
was
estimated
to
be
1.2
ug/
L.

For
surface
water,
the
Agency
has
used
a
Tier
II
(PRZM­
EXAMS)
model
with
index
reservoir
and
percent
cropped
area
(PCA)
factors
to
estimate
levels
of
disulfoton
and
sulfoxide/
sulfone
degradates
in
surface
water
at
vulnerable
(high
run­
off)
sites.
Surface
water
modeling
scenarios
chosen
for
disulfoton
are
representative
of
high
run­
off
sites
and
are
based
on
the
highest
use
rates
proposed
by
the
registrant.
The
sites
chosen
are
expected
to
represent
the
upper
10
th
percentile
for
run­
off
potential.

For
this
aggregate
assessment,
HED
refers
to
the
peak
(acute)
and
annual
average
(chronic)
surface
water
run­
off
EDWC
estimates
modeled
by
EFED
for
potatoes,
spring
wheat,
barley,
and
cotton.
Peak
EDWCs
for
parent
and
degradates
range
from
approximately
8
ug/
L
in
spring
wheat
to
39
ug/
L
in
barley,
and
annual
average
EDWCs
for
parent
and
degradates
range
from
approximately
2
ug/
L
in
cotton
to
17
ug/
L
in
potatoes.
It
should
be
noted
that
the
disulfoton
Quantitative
Usage
Analysis
(S.
Nako
memo,
5/
5/
99)
estimates
that
the
major
use
of
disulfoton
is
on
cotton
(with
a
weighted
average
of
420,000
lbs
a.
i./
year
and
an
estimated
maximum
of
840,000
lbs
a.
i./
year).
Potatoes
are
also
a
major
use
of
disulfoton
(with
a
weighted
average
of
120,000
lbs
a.
i./
year
and
an
estimated
maximum
of
195,000
lbs
a.
i./
year).

HED
notes
that
the
peak
EDWC
value
for
cotton
of
55
ug/
L
is
higher
than
the
peak
EDWC
value
for
barley
of
39
ug/
L
that
is
used
in
this
assessment.
However,
it
is
noted
that
the
Agency
default
PCA
factor
for
cotton
is
0.20.
Cotton
without
an
adjustment
for
PCA,
or
0.87,
would
overestimate
the
EDWC.
Since
the
value
of
55
ug/
L
is
not
adjusted
for
PCA
(0.87
instead
of
0.20),
the
peak
EDWC
of
39
ug/
L
is
a
more
accurate
reflection
of
the
highest
likely
acute
EDWC
value.

Drinking
Water
Levels
of
Comparison
HED
uses
Drinking
Water
Levels
of
Comparison
(DWLOC)
values
as
surrogate
measures
of
exposure.
As
part
of
aggregate
risk
assessment,
HED
compares
the
calculated
DWLOC
to
the
EDWC(
s)
estimated
for
surface
water
and
ground
water.
If
the
DWLOC
is
greater
than
the
estimated
surface
and
ground
water
concentration
(i.
e.,
if
the
DWLOC
>
EDWC)
a
determination
of
safety
can
be
made
by
the
Agency
for
aggregate
exposure
to
a
particular
pesticide.
If
the
DWLOC
values
are
not
greater
than
the
EDWC
values,
the
Agency
may
require
additional
data
concerning
water
contamination.

The
following
equations
were
used
to
calculate
the
acute,
chronic,
and
short­
term
DWLOC
values
required
for
disulfoton
aggregate
risk
assessment:

Acute:
6
DWLOCacute
(µg/
L)
=
[allowable
acute
water
exposure
(mg/
kg/
day)
x
(kg
body
weight)]
[consumption
(L/
day)
x
10
­3
mg/
µg]

where
"allowable"
acute
water
exposure
(mg/
kg/
day)
=
[aPAD
­
acute
food
(mg/
kg/
day)].

Chronic:

DWLOCchronic
(µg/
L)
=
[allowable
chronic
water
exposure
(mg/
kg/
day)
x
(kg
body
weight)]
[consumption
(L/
day)
x
10
­3
mg/
µg]

where
allowable
chronic
water
exposure
(mg/
kg/
day)
=
[cPAD
­
(chronic
food
exposure
(mg/
kg/
day)
+
chronic
non­
occupational
exposure
(mg/
kg/
day))].

Short­
term:

A
short­
term
DWLOC
for
residential
applicators
and
a
short­
term
DWLOC
for
soil
ingestion
were
calculated
using
the
reciprocal
MOE
approach.
This
approach
was
selected
as
the
required
MOEs
are
identical
for
all
MOEs
in
the
equation
(i.
e.,
MOE
=
100).

1
Aggregate
MOE
=
1
+
1
+
1
+
1
+
1
MOEFOOD
MOEWATER
MOEORAL
MOEDERMAL
MOEINHALATION
Where
the
aggregate
MOE
is
equal
to
the
required
MOE
of
100;
the
MOEFOOD
is
based
on
the
dietary
exposure
from
average
food
residues
(chronic
dietary
exposure)
compared
to
the
acute
dietary
NOAEL
of
0.25
mg/
kg/
day;
the
MOEORAL
is
based
on
the
calculated
hand­
to­
mouth
residential
exposure
compared
to
the
intermediate­
term
oral
NOAEL
of
0.03
mg/
kg/
day
(based
on
a
special
six­
month
oral
study
in
the
rat),
the
MOEDERMAL
is
based
on
the
calculated
high­
end
dermal
residential
exposures
compared
to
the
short­
term
dermal
NOAEL
of
0.5
mg/
kg/
day;
and
the
MOEWATER
is
based
on
allowable
short­
term
water
exposure
from
average
drinking
residues
compared
to
the
acute
dietary
NOAEL
of
0.25
mg/
kg/
day.
The
MOEINHALATION
is
not
included
in
this
calculation
as
exposure
via
the
inhalation
route
of
exposure
is
considered
negligible
(i.
e.,
all
residue
was
non­
detectable,
or
below
the
level
of
quantitation).

After
solving
for
the
term
MOEWATER,
allowable
short­
term
water
exposure
can
be
calculated
as
follows,
where
the
acute
dietary
NOAEL
is
0.25
mg/
kg/
day.

MOEWATER
=
Short­
term
oral
or
acute
dietary
NOAEL
Allowable
Short­
Term
Water
Exposure
Using
the
allowable
short­
term
water
exposure
value,
short­
term
DWLOC
values
are
calculated
as
follows:
7
DWLOCshort­
term
(µg/
L)
=
[allowable
short­
term
water
exposure
(mg/
kg/
day)
x
(kg
body
weight)]
[consumption
(L/
day)
x
10
­3
mg/
µg]

Acute
Aggregate
Risk
The
acute
aggregate
risk
assessment
for
disulfoton
addresses
exposure
from
food
and
drinking
water
only.
Acute
dietary
risk
estimates
are
well
below
the
Agency's
level
of
concern
(
#
100%
of
the
aPAD)
for
the
general
U.
S.
population
and
all
population
subgroups.
An
acute
DWLOC
was
calculated
for
disulfoton
based
on
acute
dietary
food
exposure
and
default
body
weight
and
water
consumption
figures.

As
shown
in
Table
1
below,
the
EDWC
for
ground
water
(1.2
µg/
L)
is
below
the
acute
DWLOC
for
all
population
subgroups.
The
peak
EDWCs
for
surface
water
range
from
approximately
8
µg/
L
to
39
µg/
L,
depending
on
the
crop
they
were
modeled
on,
and
are
below
the
acute
DWLOC
for
the
U.
S.
population,
females
13­
50,
and
seniors
55
and
older.
The
peak
EDWC
for
surface
water
(39
µg/
L;
based
on
barley)
exceeds
the
DWLOC
for
children
1­
6
and
may
cause
an
acute
aggregate
risk
of
concern.
8
Table
1:
Acute
Drinking
Water
Levels
of
Comparison
Acute
Surface
and
Ground
water
Population
Subgroup
1
PRZM/
EXAMS
(µg/
L)
SCIGROW
(µg/
L)
aPAD
(mg/
kg/
d)
Acute
Food
Exposure
(mg/
kg/
d)
Allowable
Acute
Water
Exposure
(mg/
kg/
d)
DWLOCacute
(µg/
L)

U.
S.
Population
8
­
39
1.2
0.
0025
0.000176
0.00232
81
Children
(1­
6
years
old)
8
­
39
1.2
0.
0025
0.000239
0.00226
23
Females
(13­
50
years
old)
8
­
39
1.2
0.
0025
0.000084
0.00242
72
Seniors
(55+
years
old)
8
­
39
1.2
0.
0025
0.000184
0.00232
81
1
Population
subgroups
chosen
were
U.
S.
population
(70
kg.
body
weight
assumed,
2
liters
water/
day),
the
infant/
child
subgroup
with
the
highest
food
exposure
(10
kg.
body
weight
assumed,
1
liter
water/
day),
the
female
subgroup
with
the
highest
food
exposure
(60
kg.
body
weight
assumed,
2
liters
water/
day),
and
the
seniors
55+
subgroup
(70
kg
body
weight
assumed,
2
liters
water/
day)
which
has
a
higher
dietary
exposure
than
the
U.
S.
population.

Chronic
Aggregate
Risk
The
chronic
aggregate
risk
for
disulfoton
addresses
exposure
from
food
and
drinking
water
only.
Chronic
residential
exposures
(i.
e.,
>180
days
exposure)
to
disulfoton
are
not
expected
and
therefore
are
not
included
in
this
chronic
aggregate
assessment.
Chronic
dietary
risk
estimates
are
below
the
Agency's
level
of
concern
(
#
100%
of
the
cPAD)
for
the
general
U.
S.
population
and
all
population
subgroups.
A
chronic
DWLOC
was
calculated
for
disulfoton
based
on
chronic
dietary
food
exposure
and
default
body
weight
and
water
consumption
figures.

As
shown
in
Table
2
below,
the
chronic
EDWC
for
ground
water
(1.2
µg/
L)
is
below
the
chronic
DWLOC
for
the
U.
S.
population,
females
13­
50
years
old,
and
children
1­
6
years
old.
Chronic
aggregate
risks
from
disulfoton
residues
in
ground
water
are
not
expected
to
be
of
concern.

The
chronic
EDWCs
for
surface
water
range
from
approximately
2
µg/
L
to
17
µg/
L,
depending
on
the
crop
they
were
modeled
on.
The
highest
EDWC
of
17
µg/
L
(based
on
potatoes)
exceeds
the
chronic
DWLOC
values
for
all
population
subgroups
and
would
result
in
a
chronic
aggregate
risk
of
concern.
The
lowest
EDWC
of
2
µg/
L
(based
on
cotton)
would
still
result
in
a
chronic
aggregate
risk
of
concern
for
children
1­
6
years
old,
but
not
for
the
U.
S.
population
and
females
13­
50.
9
Table
2:
Chronic
Drinking
Water
Levels
of
Comparison
Chronic
Surface
and
Ground
water
Population
Subgroup
1
PRZM/
EXAMS
(µg/
L)
SCIGROW
(µg/
L)
cPAD
(mg/
kg/
d)
Chronic
Food
Exposure
(mg/
kg/
d)
Allowable
Chronic
Water
Exposure
(mg/
kg/
d)
DWLOCchronic
(µg/
L)

U.
S.
Population
2
­
17
1.2
0.
00013
0.000003
0.000127
4.5
Children
(1­
6
years
old)
2
­
17
1.2
0.
00013
0.000005
0.000125
1.3
Females
(13­
50
years
old)
2
­
17
1.2
0.
00013
0.000003
0.000127
3.8
1
Population
subgroups
chosen
were
U.
S.
population
(70
kg.
body
weight
assumed,
2
liters
water/
day),
the
infant/
child
subgroup
with
the
highest
food
exposure
(10
kg.
body
weight
assumed,
1
liter
water/
day),
and
the
female
subgroup
with
the
highest
food
exposure
(60
kg.
body
weight
assumed,
2
liters
water/
day).

Short­
term
Aggregate
Risk
The
short­
term
aggregate
risk
for
disulfoton
addresses
exposure
from
food
uses,
residential
use,
and
drinking
water
contamination.
Residential
use
is
assessed
for
dermal
exposure
to
adult
handlers
and
oral
exposure
to
children
through
incidental
soil
ingestion.
Inhalation
exposure
is
not
part
of
the
short­
term
aggregate
assessment
as
data
indicate
negligible
exposure.
Short­
term
DWLOC
estimates
are
calculated
for
disulfoton
based
on
chronic
dietary
(food)
exposure
estimates
and
default
body
weight
and
water
consumption
values.

Short­
term
DWLOC
estimates
are
presented
in
Tables
3A
and
3B
below.
Table
3A
presents
the
DWLOC
estimates
based
on
short­
term
dermal
and
incidental
oral
exposure
to
the
non­
Bayer
supported
homeowner
products.
Table
3B
presents
the
DWLOC
estimates
based
on
short­
term
dermal
and
incidental
oral
exposure
to
the
Bayer
Advanced
Garden
2­
in­
1
Systemic
Rose
and
Flower
Care®.

It
should
be
noted
that
the
short­
term
DWLOC
values
are
based
on
dermal
exposure
values
from
exposure
scenarios
that
have
individual
MOEs
greater
than
100
only.
Exposure
scenarios
with
MOEs
less
than
100
were
not
included
in
the
short­
term
aggregate
assessment.
These
scenarios
include
the
following:

(1)
loading/
applying
granulars
with
a
belly
grinder
for
flower
and
vegetable
gardens
(pre­
planting)
using
an
application
rate
of
0.3
lb
ai/
1000
ft
2
(flower
gardens,
MOE
=
1.1)
and
0.069
lb
ai/
1000
ft
2
(vegetable
gardens,
MOE
=
4.6)

(3)
loading/
applying
granulars,
using
a
spoon,
measuring
scoop,
shaker
can
or
by
hand,
to
flower
gardens
and
ornamental
shrubs/
small
trees
using
an
application
rate
of
0.3
lb
ai/
1000
10
ft
2
(flower
gardens,
MOE
=
34)
and
0.01
lb
ai/
four
foot
shrub
(shrubs/
small
trees,
MOE
=
41).

The
EDWC
for
ground
water
(1.2
µg/
L)
is
below
the
short­
term
DWLOC
for
all
population
subgroups.
EDWCs
in
surface
water
range
from
approximately
2
µg/
L
(based
on
cotton)
to
17
µg/
L
(based
on
potatoes,
east
of
the
Rockies).
The
highest
EDWC
of
17
µg/
L
would
slightly
exceed
the
short­
term
DWLOC
for
children
1­
6
years
old,
when
considering
the
use
of
non­
Bayer
supported
products.
Short­
term
aggregate
exposure
for
children
1­
6
years
old
may
be
of
concern
for
non­
Bayer
supported
products.
Short­
term
aggregate
exposure
is
not
of
concern
for
any
population
subgroup
for
the
Bayer­
supported
1%
granular
formulation.
11
Table
3a:
Short­
term
Drinking
Water
Levels
of
Comparison
for
the
Non­
Bayer
Supported
Products
Population
Subgroup
1
PRZM/
EXAMS
(µg/
L)
SCI
GROW
(µg/
L)
High­
end
Dermal
Exposure
2
(mg/
kg/
d)
High­
end
Inhalation
Exposure
(mg/
kg/
d)
Hand­
to­
mouth
Oral
Exposure
(mg/
kg/
d)
3
Chronic
Food
Exposure
(mg/
kg/
d)
Allowable
Short­
Term
Water
Exposure
(mg/
kg/
d)
DWLOC
short

term
(µg/
L)

U.
S.
Population
2
­
17
1.2
0.
0034
negligible
n/
a
0.
000003
0.000797
28
Children
(1­
6
years
old)
2
­
17
1.2
n/
a
negligible
0.00013
0.000005
0.00141
14
Females
(13­
50
years
old)
2
­
17
1.2
0.
0034
negligible
n/
a
0.
000003
0.000797
24
1
Population
subgroups
chosen
were
U.
S.
population
(70
kg.
body
weight
assumed,
2
liters
water/
day),
the
infant/
child
subgroup
with
the
highest
food
exposure
(10
kg.
body
weight
assumed,
1
liter
water/
day),
and
the
female
subgroup
with
the
highest
food
exposure
(60
kg.
body
weight
assumed,
2
liters
water/
day).

2
High­
end
dermal
exposure
value
of
0.0034
mg/
kg/
d
is
based
on
the
"loading/
applying
granulars
using
a
spoon,
measuring
scoop,
shaker
can,
or
by
hand"
to
vegetable
gardens
scenario.

3
Hand­
to­
mouth
oral
exposure
value
of
0.00013
mg/
kg/
d
is
based
on
incidental
soil
ingestion
for
flowerbeds.
12
Table
3b:
Short­
term
Drinking
Water
Levels
of
Comparison
for
the
Bayer­
Supported
1%
Granular
Formulation
Population
Subgroup
1
PRZM/
EXAMS
(µg/
L)
SCI
GROW
(µg/
L)
High­
end
Dermal
Exposure
2
(mg/
kg/
d)
High­
end
Inhalation
Exposure
(mg/
kg/
d)
Hand­
to­
mouth
Oral
Exposure
3
(mg/
kg/
d)
Chronic
Food
Exposure
(mg/
kg/
d)
Allowable
Short­
Term
Water
Exposure
(mg/
kg/
d)
DWLOC
short

term
(µg/
L)

U.
S.
Population
2
­
17
1.2
0.
00033
negligible
n/
a
0.
000003
0.002332
82
Children
(1­
6
years
old)
2
­
17
1.2
n/
a
negligible
0.0000917
0.000005
0.00173
17
Females
(13­
50
years
old)
2
­
17
1.2
0.
00033
negligible
n/
a
0.
000003
0.002332
70
1
Population
subgroups
chosen
were
U.
S.
population
(70
kg.
body
weight
assumed,
2
liters
water/
day),
the
infant/
child
subgroup
with
the
highest
food
exposure
(10
kg.
body
weight
assumed,
1
liter
water/
day),
and
the
female
subgroup
with
the
highest
food
exposure
(60
kg.
body
weight
assumed,
2
liters
water/
day).

2
High­
end
dermal
exposure
value
of
0.00033
mg/
kg/
d
is
based
on
the
"loading/
applying
Bayer
Advanced
Garden
2­
in­
1
Systemic
Rose
and
Flower
Care®

Disulfoton
1%
granulars
using
a
measuring
cup/
lid"
to
shrubs
scenario.

3
Hand­
to­
mouth
oral
exposure
value
of
0.0000917
mg/
kg/
d
is
based
on
incidental
soil
ingestion
for
flowerbeds.
13
Conclusion
The
Agency's
aggregate
risk
assessment
for
disulfoton
is
based
on
exposure
estimates
for
food
and
residential
uses
and
provides
a
screening
level
assessment
of
modeled
estimates
for
drinking
water
contamination
.
Dietary
risk
estimates
are
based
on
a
refined
assessment
that
incorporates
percent
crop
treated
data,
monitoring
data,
and
processing
data.
It
is
unlikely
that
this
dietary
assessment
can
be
refined
to
any
significant
degree.
Residential
risk
estimates
are
based,
in
part,
on
a
registrant­
submitted
homeowner
garden
study
that
was
conducted
specifically
for
the
Bayer
1%
granular
formulation.
It
is
also
unlikely
that
the
residential
assessment
(for
the
1%
granular
product)
can
be
refined
to
any
significant
degree.
Further
refinements
to
the
residential
assessment
for
the
non­
Bayer
supported
products
may
be
possible
through
exposure
studies
or
improved
use
information.
However,
the
drinking
water
assessment
is
based
on
limited
monitoring
data
and
modeled
estimates,
and
is
not
considered
a
refined
estimate
that
represents
actual
disulfoton
contamination
in
finished
tapwater.

The
Agency
has
drawn
the
following
conclusions
from
its
aggregate
risk
analysis
for
disulfoton:

°
The
EDWC
estimates
for
disulfoton
residues
in
surface
water
exceed
the
Agency's
estimated
acute
DWLOC
value
for
children
1­
6
years
old,
when
the
highest
peak
EDWC
value
from
the
use
on
barley
is
considered.

°
When
the
highest
annual
EDWC
value
from
the
use
on
potatoes
(east
of
the
Rockies)
is
considered,
the
chronic
DWLOC
value
is
exceeded
for
all
population
subgroups.
When
the
lowest
annual
EDWC
value
from
the
use
on
cotton
is
considered,
the
chronic
DWLOC
value
is
exceeded
for
children
1­
6
years
old
only.

°
When
the
highest
EDWC
value
from
the
use
of
potatoes
(east
of
the
Rockies)
is
considered,
the
short­
term
DWLOC
value
is
exceeded
for
children
1­
6
years
old
when
considering
the
non­
Bayer
supported
products.
The
lowest
EDWC
value
from
the
use
on
cotton
does
not
exceed
the
short­
term
DWLOC
value
for
any
population
subgroup.

Based
on
all
available
information,
the
Agency
is
unable
to
conclude
with
reasonable
certainty
that
residues
of
disulfoton
in
drinking
water,
when
considered
along
with
exposures
from
food
and
residential
uses,
will
not
result
in
an
aggregate
risk
of
concern.
However,
since
a
range
of
EDWC
values
were
used
in
this
assessment,
and
the
exceedance
of
the
DWLOC
value
often
resulted
from
the
use
of
the
highest
EDWC
value,
any
deletion
of
use
or
reduction
in
application
rates
by
the
registrant
may
improve
the
findings
of
this
aggregate
assessment.