UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
PC
Code:
206600
DP
Barcode
D282389,
D284487
DATE:
July
31,
2002
MEMORANDUM
SUBJECT:
Updated
Drinking
Water
Assessment
to
Support
TRED
for
Fenarimol
FROM:
Norman
Birchfield,
Ph.
D.
Biologist
Environmental
Risk
Branch
IV
Environmental
Fate
and
Effects
Division
(
7507C)

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

TO:
Barry
O'Keefe,
Risk
Assessor
(
7508C)
Health
Effects
Division
Tom
Myers,
Product
Manager
Special
Review
and
Reregistration
Division
(
7508C)

This
memo
presents
revised
Tier
I
surface
water
and
groundwater
Estimated
Environmental
Concentrations
(
EECs)
for
fenarimol
and
its
aquatic
photodegradates.
This
assessment
updates
the
August
6,
2000
Drinking
Water
Assessment
from
E.
Laurence
Libelo
(
D276622).
Submissions
from
the
registrant
(
MRID
45716301,
45716302,
45716303,
45716304)
were
considered
in
this
revision.

The
surface
water
values
presented
here
were
calculated
using
FIRST
(
surface
water)
modeling
of
applications
to
turf.
The
FIRST
inputs
in
this
assessment
are
identical
to
the
previous
assessment,
except
aquatic
concentrations
were
estimated
assuming
no
aqueous
photolysis,
which
appears
to
be
fenarimol's
most
significant
route
of
dissipation,
and
minor
corrections
were
made
to
the
application
rate
and
interval.
The
result
is
intended
to
provide
a
screening
level
estimate
of
combined
concentrations
of
fenarimol
and
its
aquatic
degradates.
Although
the
combined
exposure
estimates
presented
for
parent
and
degradates
are
expected
to
be
conservative,
there
is
substantial
uncertainty
as
to
the
identity,
fate,
and
behavior
of
photolysis
degradates
due
to
shortcomings
in
the
environmental
fate
studies.
Page
2
of
7
The
surface
water
acute
EEC
for
fenarimol
and
degradates
is
261
ppb.
The
surface
water
chronic
EEC
for
fenarimol
and
degradates
is
84
ppb.
These
values
represent
the
1­
in­
10
year
peak
surface
water
concentration
and
1­
in­
10
year
mean
yearly
concentration.
Fenarimol
is
generally
stable
(
except
in
water
exposed
to
sunlight)
and
moderately
mobile
in
the
environment.
Based
on
its
chemical
properties
it
is
likely
that
fenarimol
will
accumulate
in
the
environment.
The
fate,
persistence,
and
identity
of
fenarimol's
degradates
are
largely
unknown.

The
groundwater
values
presented
were
calculated
using
the
SCIGROW
model
and
the
application
rate
to
turf.
The
SCIGROW
inputs
are
identical
to
the
previous
assessment
except
the
application
rate
was
increased
slightly
to
be
consistent
with
labeled
rates.
The
concentration
estimates
for
groundwater
are
for
parent
fenarimol
only.
The
aqueous
photoproducts
which
may
occur
in
surface
water
are
unlikely
to
be
present
in
groundwater
at
a
significant
level.

The
groundwater
acute
and
chronic
estimated
concentration
for
fenarimol
is
16
ppb.

As
stated
in
the
previous
assessment,
these
concentration
estimates
are
based
on
environmental
fate
studies
conducted
in
the
1970s
and
early
1980s.
The
quality
of
the
data
provided
by
these
studies
is
significantly
lower
then
currently
required.
By
current
standards
most
of
these
studies
would
not
be
considered
acceptable
and
the
results
would
not
be
considered
of
sufficient
quality
to
allow
an
acceptable
assessment
of
the
environmental
fate
of
this
compound.
Therefore
the
EECs
presented
here
are
somewhat
uncertain,
and
may
change
if
additional
data
become
available.

Based
on
usage
information
from
USGS
(
see
Figure
1)
and
provided
by
the
registrant,
annual
fenarimol
usage
for
turf
and
agriculture
is
well
under
100,000
pounds
per
year
distributed
across
several
states.

Figure
1.
Agricultural
fenarimol
usage
estimates
from
the
USGS.
These
estimates
do
not
include
turf
usage.
(
http://
ca.
water.
usgs.
gov/
pnsp/
use92/
fenarml.
html)
Page
3
of
7
EFED
surface
water
modeling
for
drinking
water
uses
a
percent
cropped
area
factor
(
PCA).
The
PCA
represents
the
fraction
of
a
watershed
that
is
cropped
and
treated
with
the
pesticide
being
modeled.
In
the
absence
of
having
a
PCA
factor
for
a
particular
crop
a
default
PCA
of
0.87
is
used.
The
0.87
factor
represents
the
maximum
fraction
of
a
watershed
in
the
US
that
is
agriculturally
cropped.
This
default
was
used
for
fenarimol
modeling
on
turf.
EFED
is
currently
attempting
better
define
PCA
factors
for
turf
scenarios
but
recognizes
that
it
is
unlikely
that
87%
of
a
watershed
used
for
drinking
water
would
be
treated
with
fenarimol
at
the
maximum
rate
allowed
only
for
turf
applications.

The
percent
cropped
area
factor
used
in
fenarimol
modeling
is
most
likely
overestimated
and
adds
to
the
conservatism
of
the
surface
water
assessment.
The
model
estimates
for
fenarimol
drinking
water
exposure
assume
that
87%
of
a
watershed
are
treated
at
the
maximum
application
rate
for
turf
(
the
highest
rate
allowed
on
the
RubiganTM
AS
product
label).
Given
the
relatively
low
usage
of
fenarimol
across
the
country
it
is
highly
unlikely
that
the
amount
applied
to
the
watershed
in
the
model
will
be
concentrated
in
any
real
watershed
used
to
derive
drinking
water.

The
groundwater
concentration
estimates
are
not
expected
to
be
as
conservative
as
the
surface
water
estimate.
Groundwater
used
for
drinking
water
is
more
likely
to
be
affected
by
fenarimol
use
in
the
immediate
area.
Therefore,
the
relatively
low
usage
of
fenarimol
across
the
US
would
1
From
RubiganTM
AS
label
dated
03/
31/
2000.

Page
4
of
7
be
expected
to
reduce
the
number
of
people
exposed
but
not
the
magnitude
of
exposure.
Fenarimol's
chemical
properties
(
long
persistence,
moderate
mobility)
suggest
that
groundwater
contamination
is
likely
to
occur
as
a
result
of
use
of
this
chemical.
The
magnitude
of
groundwater
contamination
would
be
expected
depend
on
the
application
rate,
the
number
of
applications,
the
soil
type,
and
the
amount
of
rainfall
and
irrigation
at
the
site.

In
summary,
the
surface
water
EECs
are
not
likely
to
underestimate
exposure
to
fenarimol
and
its
degradates
based
on
the
conservative
inputs
to
the
model
(
i.
e.,
default
PCA,
no
decay
via
the
major
degradation
pathway,
and
the
concentrated
application
scenario
modeled
is
unlikely
to
occur
in
a
real
watershed
where
drinking
water
is
derived).
The
uncertainties
related
to
the
aqueous
photoproducts
would
likely
be
addressed
through
completion
of
a
satisfactory
guideline
aqueous
photolysis
study
(
161­
2,
835.2240).
Other
uncertainties
would
likely
be
addressed
through
the
completion
of
satisfactory
guideline
studies
shown
in
Table
3.
If
modeled
groundwater
concentrations
exceed
levels
of
concern
a
prospective
groundwater
monitoring
study
should
be
conducted.

Table
1.
Model
Input
Parameters
for
Fenarimol
Water
Solubility
(
25

C)
14
mg/
L
Hydrolysis
Half­
Life
(
pH7)
stable
Aerobic
Soil
Metabolism
Half­
Life
1515
days
Aerobic
Aquatic
Metabolism
Stable
Photolysis
Half­
Life
Stable
(
in
the
previous
assessment
for
fenarimol
alone
the
input
was
3
days)

Adsorption
Coefficient
­
Kd
(
Koc)
Kd
=
6.35
(
Koc
=
400)

Application
Method
low
pressure
ground
spray
Wetted
in
Yes
Application
Rate
2.73
lbs.
a.
i./
acre1
(
2.53
lbs.
a.
i./
acre
in
previous
assessment)

Application
Frequency
2
apps
30
days
apart1
(
2
apps
7
days
apart
in
previous
assessment)
2
No
MRID
is
listed
for
this
submission:
"
Photodegradation
Study
of
C14­
Fenarimol
on
Soil
Surface"
Kent
Kabler
and
Mark
Carpenter.
September
30,
1988.
ABC
amended
final
report
#
36924.
Soil
photodegradate
concentrations
continued
to
increase
through
the
30
day
duration
of
the
study.
An
unknown
photodegradate
was
present
at
5.9%
at
study
termination.

Page
5
of
7
Table
2.
Modeling
Results
for
Application
of
Fenarimol
to
Turf
Model
Concentration
(
ppb)

current
assessment
previous
assessment
FIRST
Peak
Day
(
Acute)
261
242
FIRST
Annual
Average
(
Chronic)
84
59
SCIGROW
Ground
Water
Value
16
14
Table
3.
Status
of
Environmental
Fate
Data
Requirements
Guideline
#
Data
Requirement
MRID
/
ACC.#
Status
161­
1
Hydrolysis
84916
Fulfilled
161­
2
Photodegradation
­
water
129103
Unfulfilled
161­
3
Photodegradation
­
soil
00129102
00084918
Kabler
and
Carpenter
19882
Unfulfilled
162­
1
Aerobic
soil
metabolism
248702
Fulfilled
162­
3
Anaerobic
aquatic
metabolism
248702
Unfulfilled
162­
4
Aerobic
aquatic
metabolism
Not
available
Unfulfilled
163­
1
Aged
leaching
Adsorption/
desorption
133472
142483
Unfulfilled
Unfulfilled
163­
2
Volatility
­
lab
149384
Fulfilled
164­
1
Terrestrial
field
dissipation
117511
Unfulfilled
165­
4
Fish
Bio
Acc.
Not
available
Unfulfilled
Page
6
of
7
FIRST
MODEL
RUN
Previous
assessment:

RUN
No.
1
FOR
fenarimol
ON
turf
*
INPUT
VALUES
*
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
RATE
(#/
AC)
No.
APPS
&
SOIL
SOLUBIL
APPL
TYPE
%
CROPPED
INCORP
ONE(
MULT)
INTERVAL
Kd
(
PPM
)
(%
DRIFT)
AREA
(
IN)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
2.530(
5.052)
2
7
6.3
14.0
GROUND(
6.4)
87.0
.0
FIELD
AND
RESERVOIR
HALFLIFE
VALUES
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
METABOLIC
DAYS
UNTIL
HYDROLYSIS
PHOTOLYSIS
METABOLIC
COMBINED
(
FIELD)
RAIN/
RUNOFF
(
RESERVOIR)
(
RES.­
EFF)
(
RESER.)
(
RESER.)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
1515.00
2
N/
A
3.00­
372.00
.00
372.00
UNTREATED
WATER
CONC
(
MICROGRAMS/
LITER
(
PPB))
Ver
1.0
MAY
16,
2001
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
PEAK
DAY
(
ACUTE)
ANNUAL
AVERAGE
(
CHRONIC)
CONCENTRATION
CONCENTRATION
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
242.271
58.904
Current
assessment:

RUN
No.
1
FOR
fenarimol
ON
turf
*
INPUT
VALUES
*
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
RATE
(#/
AC)
No.
APPS
&
SOIL
SOLUBIL
APPL
TYPE
%
CROPPED
INCORP
ONE(
MULT)
INTERVAL
Kd
(
PPM
)
(%
DRIFT)
AREA
(
IN)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
2.730(
5.423)
2
30
6.3
14.0
GROUND(
6.4)
87.0
.0
FIELD
AND
RESERVOIR
HALFLIFE
VALUES
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
METABOLIC
DAYS
UNTIL
HYDROLYSIS
PHOTOLYSIS
METABOLIC
COMBINED
(
FIELD)
RAIN/
RUNOFF
(
RESERVOIR)
(
RES.­
EFF)
(
RESER.)
(
RESER.)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
1515.00
0
N/
A
.00­
.00
.00
.00
UNTREATED
WATER
CONC
(
MICROGRAMS/
LITER
(
PPB))
Ver
1.0
MAY
16,
2001
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
PEAK
DAY
(
ACUTE)
ANNUAL
AVERAGE
(
CHRONIC)
CONCENTRATION
CONCENTRATION
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
260.719
83.523
Page
7
of
7
SCIGROW
MODEL
RUNS
Previous
assessment:

RUN
No.
1
FOR
fenarimol
INPUT
VALUES
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
APPL
(#/
AC)
APPL.
URATE
SOIL
SOIL
AEROBIC
RATE
NO.
(#/
AC/
YR)
KOC
METABOLISM
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
2.530
2
5.060
400.0
1515.0
GROUND­
WATER
SCREENING
CONCENTRATIONS
IN
PPB
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
14.490690
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
A=
1500.000
B=
405.000
C=
3.176
D=
2.607
RILP=
4.423
F=
.457
G=
2.864
URATE=
5.060
GWSC=
14.490690
Current
assessment:

SCIGROW
VERSION
2.1
MAY
1,
2001
RUN
No.
1
FOR
fenarimol
**
INPUT
VALUES
**
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
APP
RATE
APPS/
TOTAL/
SOIL
AEROBIC
SOIL
METAB
(
LBS/
AC)
YEAR
SEASON
KOC
HALFLIFE
(
DAYS)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
2.730
2
5.460
400.0
1515.00
GROUND­
WATER
SCREENING
CONCENTRATION
(
IN
PPB)
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
15.5444
­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­
