Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
1
of
10
Date
21­
December­
2005
Primary
Evaluator
Tom
Bloem,
Chemist
Registration
Action
Branch
1
(
RAB1)
Health
Effects
Division
(
HED;
7509C)

Approved
by
George
F.
Kramer,
Ph.
D.,
Chemist
RAB1/
HED
(
7509C)

In
the
absence
of
signatures,
this
document
is
considered
to
be
a
draft
with
deliberative
material
for
internal
use
only.

STUDY
REPORT:

MRID
46007101.
Corely,
J.
(
2003).
Terbacil:
Magnitude
of
the
Residues
on
Watermelon.
IR­
4
PR
No.
02841.
Unpublished
study
prepared
by
IR­
4
(
North
Brunswick,
NJ).
262
p.

EXECUTIVE
SUMMARY:

Five
watermelon
trials
were
conducted
in
Regions
2
(
n=
2),
3
(
n=
1),
6
(
n=
1),
and
10
(
n=
1).
At
each
field
trial,
the
plants
were
treated
with
a
single
broadcast
spray
application
of
a
80%
wettable
powder
(
WP)
terbacil
formulation
at
0.248­
0.297
lb
ai/
acre
(
23­
40
gallons/
acre
(
GPA)).
Applications
were
made
after
planting
but
prior
to
crop
emergence.
Duplicate
control
and
treated
samples
were
collected
at
maturity,
69­
94
days
after
application.

The
harvested
samples
were
analyzed
for
residues
of
terbacil
and
metabolites
A,
B,
and
C
using
the
Dupont
method
AMR­
1719­
90
(
see
attachment
1
for
structures).
Acceptable
method
validation
and
concurrent
recovery
data
were
provided.
Based
on
the
lowest
method
validation
level
which
resulted
in
acceptable
recoveries,
the
limit
of
quantitation
(
LOQ)
for
terbacil,
metabolite
B,
and
metabolite
C
is
0.10
ppm
and
the
LOQ
for
metabolite
A
is
0.30
ppm
(
unacceptable
recoveries
at
0.10
ppm).
Since
terbacil
residues
in/
on
control
samples
from
the
field
trials
ranged
from
<
0.001­
0.182
ppm
(<
0.001
ppm
(
n=
2),
0.047­
0.078
ppm
(
n=
8),
0.134
ppm,
and
0.182
ppm),
the
study
indicated
a
LOQ
of
0.50
ppm
for
terbacil
(
acceptable
recoveries
were
attained
at
0.50
ppm
in
the
storage
stability
data
submitted
with
this
study;
see
below).
The
study
indicated
that
it
is
possible
that
the
controls
samples
which
resulted
in
terbacil
residues
of
0.134
ppm
and
0.182
ppm
may
have
been
treated
samples
but
were
mislabeled
as
untreated;
no
evidence
to
confirm
this
suspicion
is
available.
HED
notes
that
if
the
0.134
ppm
and
0.182
ppm
control
samples
are
excluded
and
based
on
the
residues
in/
on
the
remaining
control
samples,
a
terbacil
LOQ
of
at
least
0.20
ppm
would
be
established
(
assumes
LOQ
=
3x
the
background).

The
maximum
storage
interval
from
harvest
to
analysis
was
268
days.
As
part
of
the
current
study,
the
petitioner
submitted
watermelon
storage
stability
data
which
resulted
in
acceptable
recoveries
of
terbacil,
metabolites
A,
B,
and
C
following
279
days
of
storage.
However,
the
data
did
not
include
a
0­
day
analysis
to
confirm
the
fortification
level.
Adequate
storage
stability
data
have
been
previously
submitted
and
reviewed
for
terbacil
and
metabolites
A,
B,
and
C
in/
on
alfalfa
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
2
of
10
(
24
months),
apples
(
6
months),
blueberry
(
6
months),
mint
(
18
months),
milk
(
1
month),
and
sugarcane
(
6
months;
HED
Reregistration
Eligibility
Document
(
RED),
D.
Miller,
18­
Dec­
1996).
HED
concludes
that
the
combination
of
the
watermelon
storage
stability
data
submitted
with
this
study
and
the
previously
reviewed
storage
stability
data
are
sufficient
to
validate
the
current
study.

Residues
of
terbacil,
metabolite
A,
metabolite
B,
and
metabolite
C
were
<
LOQ
in/
on
all
samples
(<
0.50
ppm,
<
0.30
ppm,
<
0.10
ppm,
and
<
0.10
ppm,
respectively).
Since
the
terbacil
LOQ
is
based
on
the
detection
of
terbacil
residues
in/
on
field
trial
control
samples
at
0.134
ppm
and
0.182
ppm
and
since
the
study
indicated
that
these
samples
may
have
been
treated
samples
mislabeled
as
untreated
samples,
terbacil
residues
which
were
<
LOQ
are
reported
(<
0.001­
0.230
ppm).

STUDY/
WAIVER
ACCEPTABILITY/
DEFICIENCIES/
CLARIFICATIONS:

Provided
HED
determines
that
the
method
is
sufficiently
sensitive
(
LOQs
=
0.10­
0.50
ppm),
the
field
trial
residue
data
may
be
classified
as
scientifically
acceptable.
The
acceptability
of
this
study
for
regulatory
purposes
is
addressed
in
the
forthcoming
U.
S.
EPA
Residue
Chemistry
Summary
Document
(
D313911).

COMPLIANCE:

The
in­
life
phase
of
the
study
was
conducted
by
several
companies
and
the
analytical
phase
of
the
study
was
conducted
by
PTRL
West
Inc.
(
Richmond,
CA).
Signed
and
dated
Good
Laboratory
Practices
(
GLP),
Quality
Assurance,
and
Data
Confidentiality
statements
were
provided.
No
deviations
from
regulatory
requirements
were
reported
which
would
have
an
impact
on
the
validity
of
the
study.
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
3
of
10
N
HN
O
C(
CH3)
3
O
Cl
H3C
A.
BACKGROUND
INFORMATION
Terbacil
provides
control
of
annual
grasses
and
broadleaf
weeds
via
photosynthesis
inhibition
(
inhibition
of
photosystem
II).
Terbacil
is
readily
absorbed
by
roots
and
translocated
upward;
when
absorbed
by
leaves,
translocation
is
minimal.

Table
A.
1.
Test
Compound
Nomenclature.

Chemical
structure
Common
name
terbacil
Company
experimental
name
DPX­
D0732
IUPAC
name
3­
tert­
butyl­
5­
chloro­
6­
methyluracil
CAS
name
5­
chloro­
3­(
1,1­
dimethylethyl)­
6­
methyl­
2,4(
1H,
3H)­
pyrimidinedione
CAS
registry
number
5902­
51­
2
End­
use
product
(
EP)
Sinbar
®
80WP
(
wettable
powder
80%
terbacil
by
weigth)

Table
A.
2.
Physicochemical
Properties
of
the
Technical
Grade
Test
Compound.

Parameter
Value
Reference
Melting
point/
range
175­
177
°
C
Terbacil
Reregistration
Standard
(
8­
Mar­
1989,
R.
Schmitt)
pH
not
available
Density
1.34
g/
cm3
(
25
/

C)

Water
solubility
(
mg/
L
(
25
°
C))
710
Solvent
solubility
(
mg/
mL
(
25
°
C))
dimethylformamide
33.7
cyclohexane
22
methyl
isobutyl
ketone
13.8
butyl
acetate
9.7
Xylene
6.5
Vapor
pressure
4.7
x
10­
7
mm
Hg
(
29.5
/

C)

Dissociation
constant,
pKa
not
available
Octanol/
water
partition
coefficient
(
KOW)
81.9
UV/
visible
absorption
spectrum
not
available
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
4
of
10
B.
EXPERIMENTAL
DESIGN
B.
1.
Study
Site
Information
Temperature
and
rainfall
recordings
were
not
provided
at
any
of
the
field
trial
sites.
The
study
did
indicate
that
the
weather
was
warmer
and
wetter
than
normal
at
the
Westlaco,
TX
field
trial
and
warmer
and
drier
than
normal
at
the
Salisbury,
MD
field
trial.
Table
B.
1.1
is
a
summary
of
the
field
trial
site
conditions;
Table
B.
1.2
is
a
summary
of
the
use
pattern;
Table
B.
1.3
is
a
summary
of
the
geographical
distribution
of
the
submitted
watermelon
field
trials
and
the
suggested
geographical
distribution
for
a
US
watermelon
registration
Table
B.
1.1.
Trial
Site
Conditions.

Trial
Identification
(
City,
State;
Year;
EPA
Region)
Soil
characteristics
Meteorological
data
Type
%
Organic
Matter
pH
CEC
(
meq/
g)
1
Overall
monthly
rainfall
range
(
inches)
Overall
temperature
range
(
°
C)

Holyville,
CA;
1997;
Region
10
silty
clay
loam
0.79
7.9
not
reported
not
reported
Gainesville,
FL;
1997;
Region
3
sand
not
reported
not
reported
Tifton,
GA;
1997;
Region
2
loamy
sand
0.85
6.2
not
reported
not
reported
Salisbury,
MD;
1997;
Region
2
loamy
sand
0.92
6
not
reported
not
reported
Weslaco,
TX;
1997;
Region
62
clay
not
reported
8.3
not
reported
not
reported
1
cation­
exchange
capacity
(
milliequivalents
per
gram)
2
study
indicate
two
field
trials
conducted
in
Weslaco,
TX;
HED
considers
this
as
a
single
field
trial
as
they
were
conducted
on
the
same
farm
using
the
same
application
date,
equipment,
and
watermelon
variety
Table
B.
1.2.
Study
Use
Pattern.

Trial
Identification
(
City,
State;
Year;
EPA
Region)
EP1
Application
Tank
Mix
Adjuvants
Method;
Timing
Vol.
(
GPA)
Rate
(
lb
ai/
A)
RTI3
(
days)
Total
Rate
(
lb
ai/
A)

Holtville,
CA;
1997;
Region
10
80WP
broadcast
spray
postplanting
pre­
emergence
30
0.297
­­
0.297
none
Gainesville,
FL;
1997;
Region
3
80WP
broadcast
spray
postplanting
pre­
emergence
29
0.245
­­
0.245
none
Tifton,
GA;
1997;
Region
2
80WP
broadcast
spray
postplanting
pre­
emergence
30
0.254
­­
0.254
none
Salisbury,
MD;
1997;
Region
2
80WP
broadcast
spray
postplanting
pre­
emergence
23
0.253
­­
0.253
none
Weslaco,
TX;
1997;
Region
62
80WP
broadcast
spray
postplanting
pre­
emergence
39­
40
0.248­
0.251
­­
0.25
none
1
EP=
End­
use
Product
2
study
indicate
two
field
trials
conducted
in
Weslaco,
TX;
HED
considers
this
as
a
single
field
trial
as
they
were
conducted
on
the
same
farm
using
the
same
application
date,
equipment,
and
watermelon
variety
3
RTI
=
retreatment
interval
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
5
of
10
Table
B.
1.3.
Trial
Numbers
and
Geographical
Locations.

NAFTA
Growing
Region
watermelon
Submitted
Requested
1
2
2
2/
2
3
1
2/
1
4
5
1/
0
6
1
2/
2
7
8
9
10
1
1/
1
11
12
13
Total
5
8/
6
1
The
second
number
is
for
situations
where
a
25%
reduction
in
the
number
of
trials
is
possible
due
to
residues
<
LOQ
or
due
to
the
crop
being
a
representative
crop
used
to
obtain
a
crop
group
tolerance.

B.
2.
Sample
Handling
and
Preparation
Duplicate
treated
and
untreated
samples
were
collected
69­
94
days
after
application.
A
minimum
of
twelve
watermelons
were
collected
per
sample;
the
samples
were
reduced
by
cutting
and
sampling
a
longitudinal
section,
approximately
1­
2
inches
thick,
from
each
watermelon.
The
samples
were
placed
in
frozen
storage
within
1
hour
of
collection
and
were
shipped
frozen
to
PTRL
West
Inc.
(
Richmond,
CA)
for
analysis
via
an
ACDS
freezer
truck
or
on
dry
ice
via
overnight
delivery.
Upon
arrival
at
the
analytical
facility,
the
samples
were
stored
frozen
until
analysis.

B.
3.
Analytical
Methodology
The
samples
were
analyzed
by
PTRL
West
Inc.
(
Richmond,
CA)
for
residues
of
terbacil
and
metabolites
A,
B,
and
C
using
the
Dupont
method
AMR­
1719­
90.
Briefly,
samples
are
extracted
with
chloroform.
Water
is
added
to
the
extract
and
the
chloroform
is
evaporated.
The
aqueous
extract
is
transferred
to
separatory
funnel
along
with
acetonitrile
and
partitioned
with
hexane.
The
acetonitrile
phase
is
collected,
reduced
to
dryness,
reconstituted
in
0.1%
NaOH,
transferred
to
a
separatory
funnel,
and
partitioned
with
ethyl
acetate.
The
ethyl
acetate
phases
are
collected
and
dervatized
with
bis(
trimethylsilyl)
trifluoroacetamide
(
BSTFA)
and
1%
trimethylchlorosilane
(
TMCS;
16
hours,
room
temperature).
Water
is
added
to
the
derivatized
extract
and
the
upper
phase
is
collected
and
placed
on
top
of
a
sodium
sulfate
clean­
up
column.
The
residues
are
eluted
from
the
sodium
sulfate
column
with
ethyl
acetate,
concentrated
to
dryness,
reconstituted
in
ethyl
acetate/
hexane,
and
passed
through
a
florisil
clean­
up
column.
Residues
are
eluted
from
the
florisil
column
with
ethyl
acetate/
hexane
and
methanol/
ethyl
acetate/
toluene,
concentrated
to
dryness,
reconstituted
in
ethyl
acetate,
and
analyzed
via
gas
chromatograph/
nitrogen
phosphorus
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
6
of
10
detection
(
GC/
NPD).
Based
on
the
lowest
method
validation
level,
the
LOQ
was
0.10
ppm
for
terbacil,
metabolite
A,
and
Metabolite
C
and
0.30
ppm
for
metabolite
A
(
recoveries
of
metabolite
A
at
0.10
ppm
were
unacceptable).

C.
RESULTS
AND
DISCUSSION
Five
watermelon
trials
were
conducted
in
Regions
2
(
n=
2),
3
(
n=
1),
6
(
n=
1),
and
10
(
n=
1).
At
each
field
trial,
the
plants
were
treated
with
a
single
broadcast
spray
application
of
a
80%
WP
terbacil
formulation
at
0.248­
0.297
lb
ai/
acre.
Applications
were
made
after
planting
but
prior
to
crop
emergence.
Duplicate
control
and
treated
samples
were
collected
at
maturity,
69­
94
days
after
application.

The
harvested
samples
were
analyzed
for
residues
of
terbacil,
metabolite
A,
metabolite
B,
and
metabolite
C
using
the
Dupont
method
AMR­
1719­
90.
Concurrent
method
recovery
data
are
presented
in
Table
C.
1.
Based
on
the
lowest
method
validation
level
which
resulted
in
acceptable
recoveries,
the
LOQ
for
terbacil,
metabolite
B,
and
metabolite
C
is
0.10
ppm
and
the
LOQ
for
metabolite
A
is
0.30
ppm
(
unacceptable
recoveries
at
0.10
ppm
see
table
C.
1).
Since
terbacil
residues
in/
on
control
samples
from
the
field
trials
ranged
from
<
0.001­
0.182
ppm
(<
0.001
ppm
(
n=
2),
0.047­
0.078
ppm
(
n=
8),
0.134
ppm,
and
0.182
ppm),
the
study
indicated
a
LOQ
of
0.50
ppm
for
terbacil
(
acceptable
recoveries
were
attained
at
0.50
ppm
in
the
storage
stability
data
submitted
with
this
study;
see
below).
The
study
indicated
that
it
is
possible
that
the
controls
samples
which
resulted
in
terbacil
residues
of
0.134
ppm
and
0.182
ppm
may
have
been
treated
samples
but
were
mislabeled
as
untreated;
no
evidence
to
confirm
this
suspicion
is
available.
HED
notes
that
if
the
0.134
ppm
and
0.182
ppm
control
samples
are
excluded
and
based
on
the
residues
in/
on
the
remaining
control
samples,
a
terbacil
LOQ
of
at
least
0.20
ppm
would
be
established
(
assumes
LOQ
=
3x
the
background).

Sample
storage
conditions
and
intervals
are
summarized
in
Table
C.
2.
The
maximum
storage
interval
from
harvest
to
analysis
was
268
days.
As
part
of
the
current
study,
the
petitioner
submitted
watermelon
storage
stability
data
which
resulted
in
acceptable
recoveries
of
terbacil
and
metabolites
A,
B,
and
C
following
279
days
of
storage
(
see
Table
C.
4).
However,
the
data
did
not
include
a
0­
day
analysis
to
confirm
the
fortification
level.
Adequate
storage
stability
data
have
been
previously
submitted
and
reviewed
for
terbacil
and
metabolites
A,
B,
and
C
in/
on
alfalfa
(
24
months),
apples
(
6
months),
blueberry
(
6
months),
mint
(
18
months),
milk
(
1
month),
and
sugarcane
(
6
months;
HED
RED,
D.
Miller,
18­
Dec­
1996).
HED
concludes
that
the
combination
of
the
watermelon
storage
stability
data
submitted
with
this
study
and
the
previously
reviewed
storage
stability
data
are
sufficient
to
validate
the
current
study.

Residues
of
terbacil,
metabolite
A,
metabolite
B,
and
metabolite
C
were
<
LOQ
in/
on
all
samples
(<
0.50
ppm,
<
0.30
ppm,
<
0.10
ppm,
and
<
0.10
ppm,
respectively;
see
Tables
C.
5
and
C.
6).
Since
the
terbacil
LOQ
is
based
on
the
detection
of
terbacil
residues
in/
on
field
trial
control
samples
at
0.134
ppm
and
0.182
ppm
and
since
the
study
indicated
that
these
samples
may
have
been
treated
samples
mislabeled
as
untreated
samples,
Table
C.
5
includes
terbacil
residues
which
were
<
LOQ
(<
0.001­
0.230
ppm).
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
7
of
10
Table
C.
1.
Summary
of
Method
Validation
Recoveries
of
Terbacil
and
Metabolites
A­
C
from
Watermelon.

Matrix
Spike
level
(
ppm)
Sample
size
(
n)
Recoveries
(%)
Mean
±
std
dev
Watermelon
terbacil
0.10
3
83,
96,
137
111
±
19
1.0
3
118,
120,
111
metabolite
A
0.10
3
151,
139,
125
138
±
13
0.30
3
97,
124,
139
118
±
14
1.0
3
116,
118,
111
metabolite
B
0.10
3
61,
82,
85
76
±
13
1.0
3
51,
51,
45
49
±
3
metabolite
C
0.10
3
110,
85,
82
91
±
11
1.0
3
91,
96,
84
Table
C.
2.
Summary
of
Concurrent
Recoveries
of
Terbacil
and
Metabolites
A­
C
from
Watermelon.

Matrix
Spike
level
(
ppm)
Sample
size
(
n)
Recoveries
(%)
Mean
±
std
dev
Watermelon
terbacil
1.0
6
97,
102,
109,
119,
122,
137
114
±
15
metabolite
A
1.0
6
91,
98,
100,
103,
104,
108
101
±
6
metabolite
B
1.0
6
62,
71,
85,
87,
89,
99
80
±
11
metabolite
C
1.0
6
73,
77,
96,
100,
102,
105
92
±
14
Table
C.
3.
Summary
of
Storage
Conditions.

Matrix
(
RAC
or
Extract)
Storage
Temp.
(
°
C)
Storage
Duration
1
Interval
of
Demonstrated
Storage
Stability
watermelon,
fruit
frozen
268
days
The
petitioner
submitted
watermelon
storage
stability
data
(
see
Table
C.
4);
these
data
did
not
include
a
0­
day
analysis,
and,
therefore,
are
unacceptable.
However,
when
these
data
are
considered
with
previously
submitted
and
reviewed
terbacil,
metabolite
A,
metabolite
B,
and
metabolite
C
storage
stability
data
(
see
next
paragraph),
HED
concludes
that
the
storage
interval
for
the
watermelon
samples
has
been
validated.

Adequate
storage
stability
data
have
been
submitted
for
terbacil
and
metabolites
A,
B,
and
C
in/
on
alfalfa
(
24
months),
apples
(
6
months),
blueberry
(
6
months),
mint
(
18
months),
milk
(
1
month),
and
sugarcane
(
6
months;
HED
RED,
D.
Miller,
18­
Dec­
1996).

1
Storage
duration
from
collection
to
analysis.
All
samples
were
analyzed
within
4
days
of
extraction;
no
data
have
been
submitted
demonstrating
the
stability
of
terbacil
and
metabolites
A­
C
in
the
extracts;
since
the
fortified
samples
run
concurrent
to
the
field
trial
samples
resulted
in
acceptable
recoveries
and
since
the
fortified
samples
were
stored
in
the
same
matter
and
duration
as
the
field
trial
samples,
HED
concludes
that
the
storage
conditions
and
intervals
for
the
extracts
has
been
validated.

Table
C.
4.
Storage
Stability
Data
Submitted
with
the
Current
Study
Matrix
Analyte
Fortification
Level
(
ppm)
Storage
interval
(
days)
%
Recovery
for
Concurrent
Samples1
%
Recovery
for
Stored
Samples
Corrected
%
Recovery2
watermelon
terbacil
0.5
279
67,
71
(
69)
107,
108,
110
155,
157,
159
metabolite
A
0.5
279
84,
94
(
89)
93,
92,
93
104,
103,
104
metabolite
B
0.5
279
86,
97
(
92)
92,
93,
96
100,
101,
104
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
8
of
10
metabolite
C
0.5
279
81,
92
(
86)
93,
90,
90
108,
105,
105
1
average
in
parenthesis
2
corrected
%
recovery
=
(%
recovery
for
stored
sample)
÷
(
avg
%
recovery
for
concurrent
sample)

Table
C.
5.
Residue
Data
from
the
Watermelon
Crop
Field
Trials.

Trial
Identification
(
City,
State;
Year;
EPA
Region)
Crop;
Variety
Commodity
Total
Rate
(
lb
ai/
acre)
PHI
(
days)
Residues
(
ppm)

Terbacil1
Metabolite
A
Metabolite
B
Metabolite
C
Holtville,
CA;
1997;
Region
10
watermelon;
Calsweet
mature
fruit
1
x
0.297
94
<
0.502,
<
0.502
(
0.091,
0.046)
<
0.30,
<
0.30
<
0.10,
<
0.10
<
0.10,
<
0.10
Gainesville,
FL;
1997;
Region
3
watermelon;
Mickylee
mature
fruit
1
x
0.245
70
<
0.503,
<
0.503
(
0.028,
0.041)
<
0.30,
<
0.30
<
0.10,
<
0.10
<
0.10,
<
0.10
Tifton,
GA;
1997;
Region
2
watermelon;
Crimson
Sweet
mature
fruit
1
x
0.254
90
<
0.504,
<
0.504
(
0.039,
0.045)
<
0.30,
<
0.30
<
0.10,
<
0.10
<
0.10,
<
0.10
Salisbury,
MD;
1997;
Region
2
watermelon;
Jade
Star
mature
fruit
1
x
0.253
69
<
0.505,
<
0.505
(
0.048,
<
0.001)
<
0.30,
<
0.30
<
0.10,
<
0.10
<
0.10,
<
0.10
Weslaco,
TX;
1997;
Region
68
watermelon;
Sugar
Baby
mature
fruit
1
x
0.248­
0.251
71
<
0.506,
<
0.506
(
0.230,
0.056)
<
0.507,
<
0.507
(
0.054,
0.050)
<
0.30,
<
0.30
<
0.30,
<
0.30
<
0.10,
<
0.10
<
0.10,
<
0.10
<
0.10,
<
0.10
<
0.10,
<
0.10
1
quantified
residues
<
LOQ
are
presented
in
parenthesis
2
terbacil
residues
of
0.047
ppm
and
<
0.001
ppm
were
found
in/
on
controls
3
terbacil
residues
of
0.050
ppm
and
<
0.001
ppm
were
found
in/
on
controls
4
terbacil
residues
of
0.056
ppm
and
0.057
ppm
were
found
in/
on
controls
5
terbacil
residues
of
0.134
ppm
and
0.074
ppm
were
found
in/
on
controls;
the
study
stated
that
it
is
possible
that
the
treated
samples
were
labeled
as
untreated
and
the
untreated
samples
were
labeled
as
treated
(
there
is
no
evidence
to
confirm
this
suspicion)
6
terbacil
residues
of
0.078
ppm
and
0.074
ppm
were
found
in/
on
controls
7
terbacil
residues
of
0.182
ppm
and
0.062
ppm
were
found
in/
on
controls;
the
study
stated
that
it
is
possible
that
the
treated
samples
were
labeled
as
untreated
and
the
untreated
samples
were
labeled
as
treated
(
there
is
no
evidence
to
confirm
this
suspicion)
8
study
indicate
two
field
trials
conducted
in
Weslaco,
TX;
HED
considers
this
as
a
single
field
trial
as
they
were
conducted
on
the
same
farm
using
the
same
application
date,
equipment,
and
watermelon
variety
Table
C.
6.
Summary
of
Residue
Data
from
Crop
Field
Trials
with
Metaflumizone
Commodity
App.
Rate
(
lb
ai/
acre)
PHI
(
days)
Analyte
Residue
Levels
in
Metaflumizone
Equivalents
(
ppm)
1
n
Min.
Max.
HAFT3
Median
Mean
Std.
Dev.

water
melon
1
x
0.248­
0.297
69­
94
terbacil1
12
<
0.50
<
0.50
<
0.50
<
0.50
<
0.50
­­
metabolite
A2
12
<
0.30
<
0.30
<
0.30
<
0.30
<
0.30
­­
metabolite
B
12
<
0.10
<
0.10
<
0.10
<
0.10
<
0.10
­­
metabolite
C
12
<
0.10
<
0.10
<
0.10
<
0.10
<
0.10
­­
1
The
terbacil
LOQ
was
0.50
ppm
due
to
residues
in/
on
controls
collected
from
the
field
trials
of
<
0.001­
0.182
ppm
(<
0.001
ppm
(
n=
2),
0.047­
0.078
ppm
(
n=
8),
0.134
ppm,
and
0.182
ppm);
the
petitioner
indicated
that
it
is
possible
that
the
controls
samples
which
resulted
in
terbacil
residues
of
0.134
ppm
and
0.182
ppm
may
have
been
treated
samples
but
were
mislabeled
as
untreated;
no
evidence
to
confirm
this
suspicion
is
available.
HED
notes
that
if
the
0.134
ppm
and
0.182
ppm
control
samples
are
excluded
and
based
on
the
residues
in/
on
the
remaining
control
samples,
a
terbacil
LOQ
of
at
least
0.20
ppm
would
be
established
(
assumes
LOQ
=
3x
the
background).
2
The
LOQ
for
metabolite
A
was
0.30
ppm
due
to
unacceptable
recoveries
at
0.10
ppm
(
see
Table
C.
1).
3
HAFT
=
Highest
Average
Field
Trial.
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
9
of
10
D.
CONCLUSION
Five
watermelon
trials
were
conducted
in
Regions
2
(
n=
2),
3
(
n=
1),
6
(
n=
1),
and
10
(
n=
1).
At
each
field
trial,
the
plants
were
treated
with
a
single
broadcast
spray
application
of
a
80%
WP
terbacil
formulation
at
0.248­
0.297
lb
ai/
acre.
Applications
were
made
after
planting
but
prior
to
crop
emergence.
Duplicate
control
and
treated
samples
were
collected
at
maturity,
69­
94
days
after
application.

The
harvested
samples
were
analyzed
for
residues
of
terbacil,
metabolite
A,
metabolite
B,
and
metabolite
C
using
an
adequately
validated
method.
Based
on
the
lowest
method
validation
level
which
resulted
in
acceptable
recoveries,
the
LOQ
for
terbacil,
metabolite
B,
and
metabolite
C
is
0.10
ppm
and
the
LOQ
for
metabolite
A
is
0.30
ppm
(
unacceptable
recoveries
at
0.10
ppm).
Since
significant
terbacil
residues
were
found
in/
on
control
samples
from
the
field
trials
(<
0.001
ppm
(
n=
2),
0.047­
0.078
ppm
(
n=
8),
0.134
ppm,
and
0.182
ppm),
the
study
indicated
a
LOQ
of
0.50
ppm
for
terbacil.
The
study
indicated
that
it
is
possible
that
the
controls
samples
which
resulted
in
terbacil
residues
of
0.134
ppm
and
0.182
ppm
may
have
been
treated
samples
but
were
mislabeled
as
untreated;
no
evidence
to
confirm
this
suspicion
is
available.
HED
notes
that
if
the
0.134
ppm
and
0.182
ppm
control
samples
are
excluded
and
based
on
the
residues
in/
on
the
remaining
control
samples,
a
terbacil
LOQ
of
at
least
0.20
ppm
would
be
established
(
assumes
LOQ
=
3x
the
background).
Adequate
storage
stability
data
are
available
to
validate
the
storage
intervals.

Residues
of
terbacil,
metabolite
A,
metabolite
B,
and
metabolite
C
were
<
LOQ
in/
on
all
samples
(<
0.50
ppm,
<
0.30
ppm,
<
0.10
ppm,
and
<
0.10
ppm,
respectively).
Since
the
terbacil
LOQ
is
based
on
the
detection
of
terbacil
residues
in/
on
field
trial
control
samples
at
0.134
ppm
and
0.182
ppm
and
since
the
study
indicated
that
these
samples
may
have
been
treated
samples
mislabeled
as
untreated
samples,
terbacil
residues
which
were
<
LOQ
are
reported
(<
0.001­
0.230
ppm).

E.
REFERENCES
HED
RED,
D.
Miller,
18­
Dec­
1996
F.
DOCUMENT
TRACKING
RDI:
RAB1
Chemists
(
21­
Dec­
2005)
T.
Bloem:
806R:
CM#
2:
703­
605­
0217:
7590C
Template
Version
September
2003
Attachment
1:
Chemical
Structures
Terbacil/
PC
Code
012701/
Dupont
DACO
7.4.1/
OPPTS
860.1500/
OECD
IIA
6.3.1,
6.3.2,
6.3.3
and
IIIA
8.3.1,
8.3.2,
8.3.3
Crop
Field
Trial
­
watermelon
DP
Barcode:
D313911
MRID
No.
46007101
Page
10
of
10
N
HN
O
C(
CH3)
3
O
Cl
H3C
N
HN
O
C(
CH3)
3
O
Cl
HOH2C
N
N
O
Cl
HOH2C
O
H3C
CH3
N
N
O
Cl
H3C
O
H3C
CH3
Attachment
1:
Chemical
Structures
Name
Structure
terbacil
3­
tert­
butyl­
5­
chloro­
6­
methyluracil
5­
chloro­
3­(
1,1­
dimethylethyl)­
6­
methyl­
2,4(
1H,
3H)­
pyrimidinedi
one
metabolite
A
3­
tert­
butyl­
5­
chloro­
6­
hydroxymethyluracil
metabolite
B
6­
chloro­
2,3­
dihydro­
7­
hydroxymethyl­
3,3­
dimethyl­
5Hoxazolo
(
3,2­
a)
pyrimidin­
5­
one
metabolite
C
6­
chloro­
2,3­
dihydro­
3,3,7­
trimethyl­
5H­
oxazolo
(
3,2­
a)
pyrimidin­
5­
one
