1
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
PC
Code:
006304,
006308,
006321
DP
Barcode:
D315682
Date:
June
12,
2006
MEMORANDUM
SUBJECT:
ADDENDUM
to
the
Tier
I
Drinking
Water
Exposure
Assessment
of
Oxytetracycline
Supporting
the
Reassessment
Under
FQPA
of
Pear
and
Peach
&
Nectarine
Use
Patterns
and
the
Assessment
of
the
New
Use
Pattern,
Apple.

TO:
Lance
Wormell,
Chemical
Review
Manager
RB2/
SRRD
(
7508P)

Stephen
Schaible,
Product
Manager
RSB/
RD
(
7505P)

FROM:
Greg
Orrick,
Environmental
Scientist
ERB4/
EFED
(
7507P)

APPROVED
R.
David
Jones,
Ph.
D.,
Senior
Agronomist
BY:
Elizabeth
Behl,
Chief
ERB4/
EFED
(
7507P)

This
is
an
addendum
to
clarify
the
physical
property
and
chemical
fate
data
gaps
for
the
oxytetracycline
TRED
uses
(
pear,
peach
&
nectarine)
and
new
use
(
apple)
assessed
for
drinking
water
exposure
(
DP
Barcode:
D315682).
As
noted
in
Table
1
below,
submission
of
the
entire
fate
data
set
is
necessary
to
bring
registration
of
oxytetracycline
into
full
compliance
with
current
regulations.
Within
this
data
set,
five
studies
in
particular
 
hydrolysis,
aqueous
photolysis,
aerobic
soil
metabolism,
aerobic
aquatic
metabolism,
and
adsorption/
desorption
 
would
substantially
decrease
the
uncertainty
in
the
current
ecological
risk
assessment
and
drinking
water
exposure
assessment
and
should
be
of
higher
priority.

Due
to
limited
use
patterns
in
the
1990'
s
and
low
estimated
risk,
environmental
fate
(
Subdivision
N)
requirements
for
oxytetracycline
were
waived
in
the
reregistration
process.
The
following
table
identifies
current
outstanding
guideline
data
requirements
and
whether
or
not
current
actions
necessitate
data
submission
in
support
of
drinking
water
exposure
assessment.
2
TABLE
1.
Environmental
fate
data
gaps
table.

OPP
Guideline
#
Data
Requirement
Satisfied
Submitted
Studies
Current
Additional
Data
Need
161­
1
Hydrolysis
No
None
Hydrolysis
data
in
terms
of
oxytetracycline
equivalents
are
necessary
to
evaluate
exposure
to
the
biologically
active
ingredient.

161­
2
Aqueous
photolysis
No
None
Aqueous
photolysis
data
in
terms
of
oxytetracycline
equivalents
are
necessary
to
evaluate
exposure
to
the
biologically
active
ingredient.

161­
3
Soil
photolysis
No
None
Soil
photolysis
data
are
required
for
registration,
but
not
necessary
to
evaluate
Tier
I
drinking
water
exposure.

162­
1
Aerobic
soil
metabolism
No
None
Aerobic
soil
metabolism
data
in
terms
of
oxytetracycline
equivalents
are
necessary
to
evaluate
exposure
to
the
biologically
active
ingredient.

162­
2
Anaerobic
soil
metabolism
No
None
None
162­
3
Anaerobic
aquatic
metabolism
No
None
Anaerobic
aquatic
metabolism
data
are
required
for
registration,
but
not
necessary
to
evaluate
Tier
I
drinking
water
exposure.

162­
4
Aerobic
aquatic
metabolism
No
None
Aerobic
aquatic
metabolism
data
in
terms
of
oxytetracycline
equivalents
are
necessary
to
evaluate
exposure
to
the
biologically
active
ingredient.

163­
1
Aged
leaching/
adsorption/
desorption
No
None
Batch
equilibrium
data
in
terms
of
oxytetracycline
base
(
PC
Code
006304)
are
necessary
to
evaluate
drinking
water
exposure.

163­
2
Volatility
­
lab
No
None
Volatility
data
are
required
for
registration,
but
not
necessary
to
evaluate
Tier
I
drinking
water
exposure.

164­
1
Terrestrial
field
dissipation
No
None
Terrestrial
field
dissipation
data
are
required
for
registration,
but
not
necessary
to
evaluate
Tier
I
drinking
water
exposure.

165­
4
Fish
bioaccumulation
No
None
Fish
bioaccumulation
data
are
required
for
registration,
but
not
necessary
to
evaluate
Tier
I
drinking
water
exposure.

Satisfaction
of
these
data
requirements
is
required
by
40
CFR
Pt.
158.290
and
can
be
achieved
with
submission
of
GLP­
compliant
studies
that
include
oxytetracycline
equivalents
as
parent
compound.
Degradation
studies
of
hydroxytetracycline
monohydrochloride
(
PC
Code
006308),
oxytetracycline
calcium
salt
or
oxytetracycline
calcium
complex
(
PC
Code
006321)
that
treat
oxytetracycline
base
and/
or
other
formulations
of
the
biologically
active
ingredient
as
transformation
products
are
not
acceptable.
Such
studies
may
be
supplemental
if
accompanied
by
acceptable
degradation
studies
that
include
all
formulations
of
the
biologically
active
ingredient
as
parent
compound.
