Document ID: EPA-HQ-OPP-2004-0005-0058
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-03-31T05:00Z

1
Introduction
to
Questions
to
the
Panel
Level
II,

Terrestrial
Investigation
Model,

Version
2.0
2
1.
Guild
Parameters
Used
for
Defining
Generic
Species
The
process
for
defining
generic
species
described
in
this
document
separated
species
into
guilds
based
on
three
parameters:

°
feeding
substrate,

°
nesting
substrate,
and
°
food
type.
3
Question
1
cont'd
a.
Please
comment
on
the
representative
guilds
used
to
define
the
generic
organisms.

b.
Are
there
any
additional
parameters
that
need
to
be
considered
when
defining
the
guilds
and
associated
generic
representatives
for
a
Level
II
assessment?
If
so,
please
identify.

c.
Please
provide
direction
on
the
appropriate
application
of
the
additional
parameter(
s)
in
defining
the
generic
species
and
provide
discussion
on
how
the
additional
parameters
will
improve
the
characterization
of
the
uncertainty
in
risk
estimate.
4
2.
Assigning
Values
to
Generic
Species
Variables
Four
variables
were
used
to
define
a
generic
species:
body
weight,
frequency
on
field,
food
type
and
persistence
factor.
Values
for
each
variable
were
established
as
follows:

°
Body
Weight:
Selected
as
the
smallest
species
within
each
guild
°
Frequency
on
Field:
Selected
as
the
95th
percentile
of
available
observations
for
species
within
the
guild
5
Question
2
cont'd
°
Food
Type:
Assumed
obligate
feeders
for
granivore,
insectivore,
and
herbivore
acknowledging
that
omnivore
exposures
would
be
bracketed
by
these
groups.

°
Persistence
Factor:
Values
assigned
to
reflect
past
SAP
comments
that
repetitive
behavior
patterns
be
included
in
the
assessment.
6
Question
2
cont'd
a.
Please
comment
on
whether
the
methods
used
for
establishing
values
and
their
results
appear
to
be
appropriate
for
generic
species
for
a
Level
II
assessment.

b.
Does
the
SAP
believe
that
more
rigorous
analysis
is
necessary
or
indeed
possible
for
generic
species?
Or,
should
such
an
in­
depth
analysis
be
more
appropriately
applied
at
the
species­
specific
level
of
assessment?
Please
explain.
7
3.
Bimodal
Feeding
Pattern
&
Serial
Correlation
of
Foraging
Events
The
model
was
modified
to
incorporate
hourly
choices
for
foraging
areas,
a
bimodal
feeding
pattern,
and
to
account
for
serial
correlation
in
sequential
foraging
events.

a.
Please
comment
on
the
strengths
and
weaknesses
of
the
modified
algorithm
in
representing
avian
feeding
behavior
for
the
more
vulnerable
species
in
agro­
ecosystems.

b.
Please
provide
additional
suggestions
for
modifications
in
the
algorithm
to
more
closely
represent
avian
activity
patterns.
8
c.
Please
provide
direction
on
the
appropriate
application
of
the
additional
modifications
and
provide
discussion
on
how
the
modifications
will
improve
the
characterization
of
the
uncertainty
in
risk
estimates.
9
4.
New
Puddle
Algorithm
A
new
puddle
algorithm
was
developed
to
account
for
a
number
of
parameters
that
affect
puddling
after
a
rainfall
event
in
agro­
environments.
The
new
algorithm
addresses
rainfall
amount,
rainfall
duration,
soil
infiltration
rates,
evaporation,

degradation
and
the
stochastic
nature
of
field
topography
and
its
relation
to
puddle
formation
and
duration.
10
Question
4
cont'd
a.
Please
comment
on
the
overall
model
structure
in
relation
to
mimicking
puddles
in
agroenvironments
including
any
suggestions
on
modifications
or
additional
parameters
to
considered
that
would
improve
pesticide
concentration
estimates
in
this
environmental
media.

b.
Please
provide
suggestions
for
assigning
values
to
puddle
input
variables
and
for
locating
additional
sources
of
information
that
may
help
in
defining
these
values.
11
5.
Air
Concentration
Estimation
The
model
currently
employs
an
equilibrium­
based
two
compartmental
model,
for
estimating
pesticide
air
concentration
in
the
plant
canopy.

°
Please
comment
on
the
merits
and
limitations
of
this
approaches.

°
Would
the
SAP
provide
suggestions
on
additional
alternatives
for
estimating
vapor
phase
concentrations
that
would
be
consistent
with
the
physical/
chemical
property
and
environmental
fate
data
available
to
the
Agency
as
guideline
information?
Please
comment
on
the
merits
and
limitations
of
these
additional
approaches.
12
6.
Relating
Inhalation
Exposure
to
Oral
Exposure
Toxicity
Endpoints
The
absence
of
avian
inhalation
toxicity
data
and
the
need
to
track
all
exposure
routes
simultaneously
has
lead
to
the
development
of
a
method
to
relate
inhalation
exposures
to
oraldose
equivalents.
The
method
uses
the
relationship
between
mammalian
inhalation
and
oral
acute
toxicity
endpoints
along
with
an
adjustment
factor
to
account
for
some
basic
physiological
differences
between
the
mammalian
and
avian
lungs
assumed
important
to
inhaled
pesticide
bioavailability.
13
Question
6
cont'd
a.
Please
comment
on
whether
OPP's
proposed
approach
for
relating
inhalation
exposure
to
oraldose
equivalents
addresses
SAP's
previous
comments
concerning
the
use
of
the
mammalian
inhalation/
oral
relationship
for
estimating
toxicity
in
birds.

b.
Please
provide
suggestions
on
alternatives
for
estimating
avian
inhalation
toxicity
that
would
be
consistent
with
the
kinds
of
toxicity
data
generally
available
to
the
Agency.
14
7.
Estimating
Dermal
Exposure
The
incidental
dermal
contact
model
relies
on
methods
currently
employed
by
the
OPP's
Health
Effects
Division
that
rely
on
estimates
of
foliar
contact
and
dislodgeable
foliar
residues
to
estimate
an
external
dermal
dose.

a.
Please
comment
on
applying
this
general
approach
to
birds
and
whether
any
other
model
alternatives
have
been
used
for
wildlife
dermal
exposure.
15
b.
If
alternative
models
for
estimating
dermal
exposure
for
birds
are
available,
please
discuss
their
advantages
and
limitations
in
comparison
to
the
proposed
model.
16
Question
7
cont'd
c.
Please
comment
on
the
following:

1.)
The
reliance
on
the
lower
leg
and
foot
as
the
significant
contact
area
for
birds.
Are
other
portions
of
avian
anatomy
significant?
If
so,

which
other
areas
should
be
included?

2.)
Recognizing
that
the
use
of
human
foliar
contact
data
has
limitations,
can
the
SAP
share
any
insights
on
available
data
that
would
allow
for
a
more
specific
foliar
contact
rate
estimate
for
birds?

3.)
Is
the
SAP
aware
of
any
data
specific
to
pesticide
foliar
residue
transfer
coefficients
for
wildlife?
If
so,
please
identify.
17
8.
Relating
Dermal
Exposure
to
Oral
Exposure
Toxicity
Endpoints
The
general
absence
of
avian
dermal
toxicity
data
and
the
need
to
track
all
exposure
routes
simultaneously
have
lead
to
the
development
of
a
method
to
relate
dermal
exposures
to
oraldose
equivalents.
The
method
uses
existing
avian
dermal
toxicity
for
a
subset
of
pesticides
to
establish
a
relationship
between
avian
dermal
18
Question
8
cont'd
approach
and
oral
acute
toxicity
endpoints.
It
is
recognized
that
this
is
statistically
limited
with
regards
to
the
strength
of
that
relationship,
and
that
this
method
is
constrained
by
the
limited
number
of
pesticide
modes
of
action
considered.

°
Please
provide
suggestions
regarding
other
route
normalization
techniques.
19
9.
Physiologically­
based
TK
Modeling
The
methods
developed
to
estimate
risk
from
multimedia
and
different
routes
of
exposure
are
based
on
external
dose
estimates
that
do
not
directly
account
for
physiological,
morphological,

and
biochemical
processes
that
underlie
the
TK
behavior
of
a
pesticide.
In
human
health
and
aquatic
life
risk
assessments
for
drugs,
and
in
some
cases
environmental
contaminants,
use
of
20
Question
9
cont'd
physiologically­
based
PB­
TK
models,
are
beginning
to
be
employed
to
derive
internal
dose
estimates
for
more
refined
dose­
response
analyses
and
to
support
route­
to­
route
and
interspecies
extrapolation.
In
this
regard,
PB­
TK
modeling
was
mentioned
by
the
SAP
during
the
2001
review
of
the
case
studies.
21
Question
9
cont'd
a.
If
you
are
aware
of
any
developmental
work
on
avian
PB­
TK
models
since
2001,
please
discuss.

Is
the
SAP
aware
of
information
sources
that
have
compiled
measured
physiological,

morphological,
and/
or
biochemical
parameters
that
are
required
to
develop
avian
PB­
TK
models?
If
so,
please
comment.
22
Question
9
cont'd
b.
Recognizing
that
research
to
support
PB­
TK
models
is
a
long­
term
and
collaborative
endeavor
across
the
Agency
and
the
scientific
community,
identifying
potential
applications
in
a
risk
assessment
context
can
provide
insights
for
prioritizing
developmental
efforts.
In
this
regard,

any
suggestions
by
the
SAP
in
terms
of
an
incremental
application
of
physiologically­
based
perspectives
in
problem
formulation,
analysis
23
Question
9
cont'd
and/
or
the
risk
characterization
phases
of
an
assessment
would
be
welcomed.
In
addition,

any
suggestions
that
may
be
helpful
to
the
broader
scientific
community
in
terms
of
research
priorities
to
develop
avian
PB­
TK
models
would
be
appreciated.