Document ID: EPA-HQ-OPP-2004-0005-0007
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-03-08T05:00Z

Chapter
V,
Page
1
of
6
Chapter
V.
Next
Steps
This
chapter
discusses
the
steps
needed
to
finalize
the
Level
II
models
(
Version
2.0)
along
with
some
of
the
steps
necessary
to
move
toward
implementation
of
these
models,
such
as
training
and
outreach.
The
chapter
concludes
with
ideas
for
building
partnerships
with
organizations
outside
of
OPP
to
refine
the
Level
II
models.
Several
projects,
which
focus
on
reducing
some
of
the
uncertainties
associated
with
the
models,
are
discussed
as
well.

A.
Finalizing
the
Level
II
Models
(
Version
2.0)

After
receiving
the
SAP's
comments
and
recommendations,
OPP
will
consider
and
incorporate
them,
as
appropriate,
and
further
develop
and
refine
the
models.
Finalizing
the
Level
II
models
will
involve
the
following
steps:

°
Terrestrial
Level
II
Model
­
Conduct
further
sensitivity
analysis
to
define
the
relationship
of
the
input
parameters
to
the
estimates
of
risk.
The
inhalation
and
puddle
modules
of
the
model
will
also
be
calibrated
with
existing
data.

°
QA/
QC
Plan
­
Complete
documenting
the
models
according
to
EFED's
internal
QA/
QC
guidance
and
procedures
to
ensure
that
models
are
properly
documented
and
of
adequate
quality
to
assess
the
effects
of
pesticides
on
fish
and
wildlife
with
specified
levels
of
reliability.
This
includes
the
selection
of
the
appropriate
standards
by
which
the
level
of
model
performance
can
be
judged
(
e.
g.,
does
the
model
calculate
aerobic
half­
life
as
it
was
designed
to
do).
This
internal
QA/
QC
guidance
has
been
approved
by
the
OPP
Quality
Assurance
Manager
and
is
currently
in
use
in
EFED
(
Appendix
L).

°
Beta­
Testing
­
Conduct
beta
testing,
focusing
on
rigorous
case
studies
which
will
test
all
of
the
features
and
components
of
the
models.
In
these
studies,
different
pesticide
examples
will
be
used
with
varying
amounts
of
data
and
levels
of
risk.
The
results
of
beta­
testing
will
also
be
compared
for
consistency,
and
the
adequacy
of
the
instructions
for
using
the
model
will
be
evaluated.
Participants
will
include
EFED
scientists,
but
may
be
expanded
to
other
OPP
divisions
and
other
EPA
offices
to
provide
an
outside
perspective.

°
Model
Maintanance
­
Develop
procedures
and
mechanisms
for
maintaining
the
models.
As
the
models
are
used,
additional
modifications
may
be
necessary.

B.
Training
Training
for
risk
assessors
and
risk
managers
is
critical
to
implementing
the
Level
II
models.
Risk
assessors
will
need
to
know
how
and
when
to
conduct
a
Level
II
probabilistic
assessment
and
how
to
develop
a
transparent,
clear,
consistent
and
reasonable
risk
characterization.
Risk
managers
will
also
need
to
participate
in
training
to
ensure
they
fully
Chapter
V,
Page
2
of
6
understand
the
basic
components
of
the
models,
the
resulting
risk
characterization,
and
when
probabilistic
assessments
should
be
conducted.

1.
Risk
Assessors
Training
will
include
background
information
on
the
use
of
risk
assessment
software,
basic
and
advanced
statistics,
and
how
to
conduct
a
probabilistic
assessment.
Once
the
background
courses
have
been
completed,
training
will
focus
on
the
use
of
the
Level
II
models.
The
course
will
include
a
training
manual/
user's
guide,
which
will
be
the
primary
source
of
information
for
using
the
Level
II
models.
This
comprehensive
guide
will
include
an
overview
of
the
model
and
the
various
modules,
system
resource
requirements,
guidance
regarding
input
parameters,
reporting
results,
and
other
related
topics.
The
training
will
include
case
studies
and
a
risk
assessment
exercise.

Training
will
also
include
information
on
developing
a
robust
risk
characterization
for
communicating
the
key
findings
of
the
assessment,
strengths
and
weaknesses,
and
a
description
of
the
uncertainties
and
assumptions.
Emphasis
will
be
placed
on
developing
risk
characterizations
that
are
transparent,
clear,
consistent,
and
reasonable.

Training
for
scientists
outside
of
OPP
has
been
discussed
and
may
include
short
courses
at
professional
meetings
such
as
the
Society
for
Environmental
Toxicology
and
Chemistry.

2.
Risk
Managers
The
Division
plans
to
provide
briefings
that
include
an
overview
and
demonstration
workshops.
The
workshops
may
include
an
overview
of
Level
II
models
and
case
studies
to
illustrate
how
the
models
work
with
a
comparison
to
the
probabilistic
assessments
conducted
for
human
health.

It
is
critical
that
a
discussion
of
risk
characterization
be
included
in
both
briefings
and
workshops.
Risk
managers
need
to
thoroughly
understand
this
final
component
of
the
risk
assessment
process
because
it
synthesizes
the
conclusions
and
provides
a
summary
of
assumptions,
scientific
uncertainties,
and
the
strengths
and
weaknesses
of
the
analysis.

3.
Risk
Assessors
and
Risk
Managers
A
workshop
focusing
on
when
to
conduct
a
probabilistic
assessment
using
the
Level
II
models
is
also
being
planned.
Workshop
participants
will
use
a
problem
formulation
case
study
and
participate
in
a
planning
dialogue
which
considers
management
goals
and
options,
the
scope
and
complexity
of
the
risk
assessment,
timeframe,
and
available
resources.
To
maximize
the
benefit
of
this
workshop,
risk
managers
and
risk
assessors,
who
are
both
critical
to
the
problem
formulation
stage
of
a
risk
assessment,
will
be
invited
to
participate.
Chapter
V,
Page
3
of
6
C.
Outreach
Outreach
is
an
essential
element
in
implementing
a
probabilistic
approach
to
ecological
risk
assessment.
Keeping
other
government
agencies,
academia,
contract
laboratories,
environmental
advocacy
groups,
and
industry
informed
provides
an
open
and
transparent
process.
One
of
the
key
tools
that
OPP
will
use
to
inform
the
public
is
the
following
Web
site
for
this
initiative.

http://
www.
epa.
gov/
oppefed1/
ecorisk/
index.
htm
Access
to
the
Level
II
models
and
presentations
to
professional
societies
will
be
available
on
this
Web
site.
In
the
near
future,
OPP
plans
to
expand
the
Web
site
to
include
an
overview
of
the
screening
level
assessment,
which
is
conducted
at
Level
I.

To
inform
the
states
and
other
stakeholders,
OPP
plans
to
provide
updates
on
the
Level
II
models
to
the
Pesticide
Program
Dialogue
Committee
and
the
State
FIFRA
Issues
Research
and
Evaluation
Group.
OPP
is
also
planning
a
series
of
briefings
for
other
federal
agencies,
such
as
the
U.
S.
Fish
and
Wildlife
Service
and
the
U.
S.
National
Oceanic
and
Atmospheric
Administration.
Another
outreach
venue
will
be
the
EPA
Probabilistic
Risk
Assessment
Colloquium,
which
will
occur
later
this
year
and
involve
other
EPA
offices
such
as
the
Office
of
Water,
Office
of
Research
and
Development,
Office
of
Solid
Waste
and
Emergency
Response,
and
EPA
Regions.

To
ensure
maximum
scientific
exchange
and
discussion,
the
Agency
plans
to
participate
in
nationally
recognized
professional
meetings,
such
as
the
Society
for
Environmental
Toxicology
and
Chemistry
as
well
as
international
workshops,
such
as
the
European
Workshop
on
Probabilistic
Risk
Assessments
for
the
Environmental
Effects
of
Plant
Protection
Products
(
EUFRAM),
and
meetings
with
the
Organization
for
Economic
Cooperation
and
Development
(
OECD)
Ad
Hoc
Risk
Assessment
Advisory
Body,
and
Canada's
Pest
Management
Regulatory
Agency.

D.
Building
Partnerships
and
Future
Directions
By
continuing
to
build
on
existing
partnerships,
OPP
will
be
better
positioned
to
refine
the
Level
II
models
and
create
synergies
with
other
Agency
programs
to
reach
common
goals.
For
example,
OPP
has
been
collaborating
with
EPA's
Office
of
Research
and
Development
(
ORD)
on
several
projects
of
interest,
which
focus
on
reducing
significant
model
uncertainties.
Both
offices
plan
to
participate
in
a
meeting
with
the
SAP
in
the
future
to
discuss
the
progress
and
findings
of
these
projects
and
receive
feedback
on
future
directions.
OPP
also
hopes
to
expand
its
collaboration
efforts
to
include
other
agencies
and
stakeholders
as
well.

1.
Addressing
Uncertainties
Related
to
Effects
Characterization
Chapter
V,
Page
4
of
6
a.
Extrapolation
Research
for
Predicting
Toxicological
Responses
Currently
the
Level
II
Aquatic
Model
uses
standardized
aquatic
toxicity
tests
and
a
classical
statistical
method
(
e.
g.,
normal
distribution
of
Log
LC50'
s)
to
determine
species
sensitivity
distributions.
A
key
area
of
uncertainty
results
when
not
enough
data
are
available
to
use
a
classical
statistical
method.
The
extrapolation
methods
currently
available
are
limited
and
a
comprehensive
review
of
newer
data
sets
is
needed
to
establish
more
realistic
and
less
uncertain
extrapolation
factors.

In
response
to
this
need,
ORD
began
to
work
on
identifying
and
compiling
a
collection
of
data
sets
on
acute
and
chronic
toxicity,
across
chemical
modes
of
action,
to
aquatic
species
that
would
be
relevant
and
applicable
to
the
standardized
aquatic
toxicity
tests
currently
used
to
support
pesticide
registration.
These
data
sets
have
been
identified,
and
the
distribution
of
toxicity
across
taxa
and
the
inter­
and
intra­
species
variability
in
toxicity
is
being
evaluated
for
its
utility
to
establish
distributions
for
relevant
taxa.

ORD's
Aquatic
Stressors
Research
Plan
(
EPA­
600­
R­
02­
074),
which
describes
ORD
research
supporting
EPA's
Office
of
Water
(
OW),
includes
similar
or
identical
approaches
for
developing
methods
for
extrapolating
chemical
toxicity
data
across
endpoints,
life
stages
and
species.
Integration
of
ORD's
research
related
to
reducing
extrapolation
uncertainties
across
program
offices
will
result
in
greater
harmonization
of
general
approaches
and
the
state­
of­
thescience
techniques
applied
within
OPP
and
OW.
Additional
harmonization
in
the
development
and
application
of
extrapolation
methods
and
tools
will
result
from
OPP's
collaboration
with
ORD
and
OW
scientists
in
an
on­
going
effort
to
revise
the
OW's
guidelines
for
deriving
ambient
water
quality
criteria.

b.
Advancing
Techniques
for
Assessing
Risk
of
Pesticides
A
major
area
of
uncertainty
not
currently
addressed
by
the
terrestrial
Level
II
model
is
avian
reproduction
impairment.
This
area
of
uncertainty
has
been
discussed
since
ECOFRAM
was
convened
early
in
the
initiative.
During
the
ECOFRAM
deliberations
and
in
subsequent
discussion,
there
was
a
consensus
that
the
current
avian
reproduction
test
would
need
to
be
redesigned
for
use
in
probabilistic
assessments.
These
tests
need
to
provide
a
dose­
response
relationship
based
on
the
ingested
daily
dose
instead
of
the
current
use
of
hypothesis
testing
to
determine
dietary
concentration.

ORD
has
been
examining
the
overall
approach
for
evaluating
pesticide
effects
on
avian
reproduction
and
what
laboratory
testing
can
and
cannot
provide.
OPP
will
be
working
with
ORD
to
discuss
their
findings
regarding
technical
issues
involved
with
methods
for
defining
doseresponse
relationships,
what
information
is
needed
to
address
questions
about
the
magnitude
of
pesticide
effects
to
wild
birds,
and
the
potential
for
modified
avian
reproduction
tests
to
achieve
these
goals.
Chapter
V,
Page
5
of
6
In
the
future,
assessment
techniques
will
also
need
to
be
explored
for
addressing
mortality
and
chronic
effects
to
mammals
and
amphibians.

2.
Addressing
Exposure
Uncertainties
a.
Database
of
Regional
Small
Surface
Water
Body
Characteristics
An
area
of
uncertainty
in
the
exposure
component
of
the
aquatic
Level
II
model
concerns
the
input
values
for
the
model.
These
values
include
watershed
size,
volume,
depth,
pH,
and
other
key
characteristics
that
influence
the
representation
or
extrapolation
of
the
exposure
model
for
these
waters.
To
reduce
this
uncertainty
and
to
improve
the
accuracy
of
exposure
predictions,
field
data
are
needed.
Once
the
data
are
collected,
a
database
of
regional
small
surface
water
body
(
e.
g.,
depressional
wetlands,
temporary
and
permanent
pools
and
ponds)
characteristics
will
be
developed.

In
response
to
this
need,
ORD
is
exploring
a
census
and
landscape
indicator
approach
for
deriving
these
input
values
for
small
surface
water
bodies
in
specific
hydrological
landscapes
in
the
Midwest.
This
project
is
part
of
a
larger
landscape
indicator
approach
for
pesticides
and
nutrients
in
stream
water
and
in
streambed
sediments
and
aquatic
biological
conditions
in
selected
small
streams
in
specific
hydrological
landscapes
in
the
Midwest.
Although
limited
in
scale,
the
data
generated
should
provide
useful
empirical
information
to
refine
components
of
the
exposure
model
and
potentially
provide
a
method(
s)
to
extrapolate
these
characteristics
and
their
distributions
on
a
broad
scale.

b.
Initial
Application
Date
The
aquatic
Level
II
model
will
be
refined
to
incorporate
an
initial
application
date
as
a
uniform
distribution
rather
than
a
single
input
date.
This
change
will
be
incorporated
to
reduce
the
uncertainty
about
application
date
due
to
the
sensitivity
of
the
exposure
output
to
the
selection
of
the
initial
application
day.
For
example,
random
selection
of
the
initial
application
date,
within
a
two
week
window
for
three
pesticides
with
different
environmental
half­
lives,
resulted
in
differences
between
the
smallest
and
highest
annual
peak
for
a
given
year
of
3.8
fold
for
a
relatively
non­
persistent
to
moderately
persistent
pesticides
and
only
about
1.4
fold
for
a
persistent
pesticide.

c.
Development
of
Uncertainty
and
Extrapolation
Factors
for
Metabolism
Rate
Constants
for
Use
in
Modeling
Generally
limited
data
are
available
to
estimate
the
metabolic
rate
constants
for
input
into
OPP's
runoff
and
surface
water
models,
which
leads
to
high
uncertainty
in
the
results
of
the
modeling.
As
a
result,
extrapolation
and
uncertainty
factors
are
used.
However,
they
are
based
on
a
fairly
limited
data
set
and
a
formal
evaluation
of
the
underlying
distributions
or
effect
of
the
number
of
studies
on
the
magnitude
of
uncertainty
has
not
been
conducted.
Analyses
of
a
large
Chapter
V,
Page
6
of
6
data
base
of
rate
constants
needs
to
be
evaluated
to
determine
the
nature
of
the
distributions
of
each
kind
of
metabolism
data.
The
magnitude
of
the
variability
in
each
type
of
data,
the
amount
of
uncertainty
incurred
by
using
a
limited
number
of
data
sets,
and
the
nature
of
the
correlations
between
study
types
also
need
to
be
evaluated.
The
results
of
these
analyses
will
be
used
to
reevaluate
the
extrapolation
and
uncertainty
factors
currently
used.

3.
Predictions
of
Population
Dynamics
Risk
managers,
who
determine
how
a
pesticide
will
be
regulated,
are
interested
in
receiving
information
concerning
the
probability
and
magnitude
of
population
impacts
from
the
use
of
a
pesticide.
Working
in
collaboration
with
OPP,
ORD
will
develop
tools
that
will
provide
risk
managers
with
spatially­
explicit,
population­
level
risk
assessments.
These
tools
will
allow
the
Agency
to
(
1)
extrapolate
toxicological
data
across
species
and
exposure
scenarios
of
concern,
(
2)
predict
population­
level
responses
and
for
identifying
the
responses
at
the
individual
level
that
have
the
greatest
influence
on
a
population
response,
(
3)
assess
the
relative
risk
of
chemical
and
non­
chemical
stressors
on
populations
across
large
areas,
and
(
4)
refine
exposure
estimates
to
provide
spatially­
explicit,
probabilistic
exposure
models.