Document ID: EPA-HQ-OPP-2008-0550-0033
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-10-24T04:00Z

AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)

	OPEN MEETING

	

October 28 – 31, 2008

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket Number: EPA-HQ- OPP-2008-0550

U.S. Environmental Protection Agency

Conference Center - Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202 

Selected Issues Associated with the Risk Assessment Process for
Pesticides with Persistent, Bioaccumulative and Toxic Characteristics

Please note that all times are approximate 

(See note at the end of the Agenda)

Tuesday, October 28, 2008

8:30 A.M.	Opening of Meeting and Administrative Procedures by Designated
Federal Official – Myrta Christian, M.S., Designated Federal Official,
Office of Science Coordination and Policy, EPA

8:35 A.M.	Introduction and Identification of Panel Members - Steven G.
Heeringa, Ph.D., FIFRA Scientific Advisory Panel Chair

8:45 A.M.	Welcome – Frank Sanders, Director, Office of Science
Coordination and Policy, EPA

8:50 A.M.	Welcome and Opening Remarks – Steven Bradbury, Ph.D.,
Division Director, Special Review and Reregistration Division, Office of
Pesticide Programs, EPA

9:00 A.M.	Goals and Objectives – Donald Brady, Ph.D., Division
Director, Environmental Fate and Effects Division, Office of Pesticide
Programs, EPA 

9:15 A.M	Background and Overview:  Issues Associated with Assessing
Ecological Risks of Pesticides with Persistence, Bioaccumulation, and
Toxic Characteristics - Keith Sappington, M.S., Environmental Fate and
Effects Division, Office of Pesticide Programs, EPA

9:45 A.M.	Background and Overview:  Aquatic Ecological Exposure
Assessments:  Rapid Overview of Current Methods - Ronald Parker, Ph.D.,
Environmental Fate and Effects Division, Office of Pesticide Programs,
EPA 

10:15 A.M.	Break

10:30 A.M.	Environmental Persistence Issues – Mohammed Ruhman, Ph.D., 

		Environmental Fate and Effects Division, Office of Pesticide Programs,
			EPA 

11:15 A.M.	Introduction - Donald Brady, Ph.D., Division Director,
Environmental Fate and Effects Division, Office of Pesticide Programs,
EPA 

11:30 A.M.	Current EFED Methods of Modeling Soil and Sediment Dynamics
– Ronald Parker, Ph.D., Environmental Fate and Effects Division,
Office of Pesticide Programs, EPA

12:15 P.M.	Lunch

1:15 P.M.	Overview of the AGRO Model for Pesticides - Donald Mackay,
Ph.D., 			Canadian Environmental Modeling Centre, Trent University

2:00 P.M.	Application of Environmental Fate and Food Web Bioaccumulation
			Models for Assessing Ecological Risks of PBT-type Pesticides - 		
Frank Gobas, Ph.D., School of Resource and Environmental 				Management,
Simon Fraser University 

2:45 P.M.	Sediment Transport Processes in Pesticide Models – Robert B.
			Ambrose, Jr., P.E., Ecosystems Research Division, National Exposure 	
	Research Laboratory, Office of Research and Development, EPA

3:30 P.M.	Break

3:45 P.M.	Conclusions:  Simulating Sediment Dynamics for Pesticide
Aquatic Ecological Exposure Assessments - Ronald Parker, Ph.D.,
Environmental Fate and Effects Division, Office of Pesticide Programs,
EPA

4:15 P.M.	Assessing Pesticide Bioaccumulation in Aquatic Food Webs -
Keith 			Sappington, M.S., Environmental Fate and Effects Division,
Office of 			Pesticide Programs, EPA

5:15 P.M.	Adjourn

AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)

	OPEN MEETING

	

October 28 - 31, 2008

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket Number: EPA-HQ- OPP-2008-0550

U.S. Environmental Protection Agency

Conference Center - Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202

Selected Issues Associated with the Risk Assessment Process for
Pesticides with Persistent, Bioaccumulative and Toxic Characteristics

Wednesday, October 29, 2008

8:30 A.M.	Opening of Meeting - Administrative Procedures by Designated
Federal Official - Myrta Christian, M.S., Designated Federal Official,
Office of Science Coordination and Policy, EPA

8:35 A.M.	Introduction and Identification of Panel Members - 

		Steven G. Heeringa, Ph.D., FIFRA Scientific Advisory Panel Chair

8:50 A.M.	Assessing Terrestrial Bioaccumulation - Kristina Garber, M.S.,
				Environmental Fate and Effects Division, Office of Pesticide 
Programs, 			EPA

9:30 A.M.	Assessing Long-range Transport – Faruque Khan, Ph.D., 				
Environmental Fate and Effects Division, Office of Pesticide Programs, 	
	EPA 

10:15 A.M.	Break

10:30 A.M.	Evaluating Aquatic Toxicity of Persistent, Bioaccumulative 		
	Pesticides - Brian Anderson, M.E.M., Environmental Fate and Effects 		
Division, Office of Pesticide Programs, EPA 

11:15 A.M. 	Conclusions and Path Forward – Keith Sappington, M.S.,
Environmental Fate and Effects Division, Office of Pesticide Programs,
EPA 

12:00 P.M.	Lunch

1:00 P.M.	Public Comment

3:30 P.M.	Break

3:45 P.M.	Charge to Panel – Question 1

Assessing Environmental Persistence

1.	Assessing Exposure to Parent and Degradation Products.   When
assessing the potential ecological risks of proposed pesticide uses, the
Agency is charged with considering both the parent compound and any
degradation products of concern.  In several of the case studies
presented in this White Paper, the Agency has illustrated three
approaches for assessing the PBT characteristics and exposure to parent
and degradation products. When parent and degradates are considered
sufficiently similar in their environmental fate and toxicological
properties or when these properties were unknown for the degradates, the
Agency has used the Total Residue (TR) method (i.e., the Agency modeled
the combined parent and degradate using a common set of environmental
fate and toxicological data). In situations where the environmental fate
and toxicological properties of the parent and degradate are available
and considered sufficiently dissimilar, the Agency has modeled the
environmental fate separately using the Residue Summation (RS) or
Formation/Degradation kinetics (FD) methods (i.e., modeling individual
residues from the parent and degradation products).  

Please comment on the Agency’s characterization of the strengths and
limitations of these methods and the conditions under which each method
should be applied.

To what extent does the Agency’s use of the total residue (TR) and
individual residue methods (RS, FD) reflect the current state of the
science for assessing exposure to combined parent and degradate
compounds?  

Please identify any methods the SAP would recommend for addressing
combined exposure to parent and degradate compounds based on the data
typically available for pesticide ecological risk assessments as
described in this White Paper.  

4:45 P.M.	Charge to Panel – Question 2

2.   Interpretation of Aquatic Degradation Rates for Persistent
Pesticides with High Sediment Sorption Coefficients.   The environmental
fate of persistent pesticides with high sediment sorption coefficients
is often influenced by dissipation processes (e.g., sorption on
sediment) rather than degradation processes (e.g., hydrolysis,
metabolism, photolysis).  In aquatic metabolism studies, the sorption
process can be a most important process in removing pesticide from the
water column.  This removal process, however, is not considered as a
degradation pathway because the pesticide is simply transferred from the
water column to the sediment.  Therefore, the total system half-life of
the pesticide in aquatic metabolism studies is used to represent the
most accurate degradation rate in aquatic environments.  

Considering the environmental fate data typically available to support
pesticide registration decisions, please comment on the strengths and
limitations of the Agency’s approach of using total system half-life
for assessing pesticide persistence in aquatic metabolism studies.

6:00 P.M.	Adjournment

 AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)

	OPEN MEETING

	

October 28 - 31, 2008

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket Number: EPA-HQ- OPP-2008-0550

U.S. Environmental Protection Agency

Conference Center - Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202

Selected Issues Associated with the Risk Assessment Process for
Pesticides with Persistent, Bioaccumulative and Toxic Characteristics 

Thursday, October 30, 2008

8:30 A.M.	Opening of Meeting - Administrative Procedures by Designated
Federal Official - Myrta Christian, M.S., Designated Federal Official,
Office of Science Coordination and Policy, EPA

8:35 A.M.	Introduction and Identification of Panel Members - 

		Steven G. Heeringa, Ph.D., FIFRA Scientific Advisory Panel Chair

8:50 A.M.	Follow-up from Previous Day’s Discussion – Donald Brady,
Ph.D., Division Director, Environmental Fate and Effects Division,
Office of Pesticide Programs, EPA 

9:15 A.M.	Charge to Panel – Question 3

3.  	Sediment Dynamics.  As part of its baseline ecological risk
assessment process, OPP uses environmental fate and transport computer
models to generate estimated environmental concentrations (EECs) of a
pesticide in surface water, pore water and sediment. The EECs are
generated using the EXAMS model parameterized to represent a static farm
pond receiving pesticide mass in runoff from a treated agricultural
field simulated by PRZM. It is assumed by OPP that EECs generated from
this scenario are conservative representations of expected pesticide
concentrations not only in this farm pond but also in small first and
second order streams that receive runoff-containing pesticide residues
from many fields.  Currently, the OPP modeling approach accounts for
movement of pesticide mass between the water column and benthic region
using a set of “lumped” parameters (PRBEN) and a mass transfer
coefficient.  These parameters are intended to implicitly account for
pesticide mass transfer due to processes such as diffusion, settling,
resuspension and other processes that tend to mix the sediment layer
with the water column. The current OPP modeling approach does not
include inflow of sediment to the water body which could lead to burial
of sediment containing pesticide through deposition.

Please comment on the strengths and limitations of OPP’s current
approach for modeling pesticide transport between the water column and
benthic region which relies on the use of lumped parameters to represent
multiple transport mechanisms (e.g., diffusion, settling, resuspension)
in static ponds.

In the context of screening-level and refined assessments, please
comment on the strengths and limitations of simulating pesticide burial
by sediment in static ponds as a process that renders pesticide
permanently unavailable for biological interaction (i.e., not
bioavailable).

Please comment on the strengths and limitations of models described in
the White Paper with respect to modeling pesticide transport via
sediment dynamics.  Which processes associated with sediment-based
pesticide transport (e.g., sediment enrichment, settling, re-suspension,
burial, bioperturbation, pore water diffusion, scour, bank erosion)
would be most important to consider in static ponds?  Which processes
would be most important in flowing water systems?

10:30 A.M.	Break

10:45 A.M.	Charge to Panel - Question 4

Assessing Bioaccumulation Potential

4.	Aquatic Bioaccumulation Methods. Traditionally, OPP’s assessment of
pesticide bioaccumulation potential in aquatic organisms has relied
extensively on the use of bioconcentration factors (BCFs).  BCFs
consider direct chemical uptake through aqueous exposure routes only.
For organic chemicals with PBT characteristics, bioaccumulation from
non-aqueous exposure routes (e.g., diet and sediment) can be
substantial.  For these chemicals, risk assessments in other Agency
programs (e.g., Office of Water ambient water quality criteria,
Superfund site risk assessments, Office of Research and Development
ecological risk assessments) have used a combination of laboratory-,
field- and model-based methods for incorporating bioaccumulation via
multiple exposure routes. In the pesticides program, a similar
integrative approach is being considered for assessing the
bioaccumulation potential of organic pesticides with PBT
characteristics. This approach considers the type and quantity of data
typically available for pesticide ecological risk assessments, relative
strengths and limitations of each bioaccumulation assessment method, and
uncertainty associated with bioaccumulation predictions using each
method. 

Please comment on the need to consider alternatives to the BCF method
for assessing the bioaccumulation potential of organic pesticides with
PBT characteristics.

Please comment on the applicability of the Agency’s approach of using
multiple methods (including laboratory-, field- and model-based methods)
for assessing bioaccumulation potential of organic pesticides as
illustrated in the White Paper.

12:00 P.M.	Lunch

1:00 P.M.	Charge to Panel – Question 5

5.	Terrestrial Bioaccumulation in Terrestrial Food Webs.  The Agency
currently assesses risks to terrestrial vertebrates that result from
direct deposition of pesticides on food items that inhabit the treatment
area.  In general, this assessment is considered to provide relatively
“high end” estimates of acute exposure through the ingestion
pathway. At this time, however, the Agency does not routinely assess
pesticide bioaccumulation in terrestrial food webs in non-target sites,
in part, because the methods and tools for assessing bioaccumulation in
terrestrial food webs are not as developed compared to those for aquatic
food webs. 

Please comment on factors (e.g., physico-chemical properties) the Agency
can consider to identify when bioaccumulation potential in terrestrial
food webs may be important to consider in its pesticide ecological risk
assessments?

Please comment on the current state of the science underlying existing
terrestrial food web bioaccumulation models and their relative strengths
and limitations. 

2:00 P.M.	Charge to Panel – Question 6

Assessing Toxicity

6.	Incorporating Multiple Exposure Routes.  For a number of organic
chemicals with PBT profiles, aquatic organism exposure via non-aqueous
routes (diet, sediment) can be important relative to direct exposure
from water.  Most standard aquatic toxicity test studies submitted to
the Agency for pesticide registration do not incorporate realistic
chemical exposure through the diet (e.g., water only exposures). 
Therefore, toxicity reference values (TRVs) from these studies may
underestimate actual environmental effects. To address this concern,
other Programs within the Agency have proposed using a tissue residue
approach (TRA) for quantifying chemical toxicity (e.g., Office of Water,
Office of Research and Development).  For quantifying toxicity of
organic pesticides with PBT characteristics, the Agency is also
considering the use of the TRA.

 

Please comment on the strengths and limitations of the tissue residue
approach for addressing pesticide toxicity from multiple exposure routes
and other methods the SAP deems appropriate.  

In the context of the tissue residue approach, please comment on the
strengths and limitations of using measured and predicted tissue
residue-effect relationships that are derived from water-only exposures
in laboratory toxicity tests.

3:00 P.M.	Break

3:15 P.M.	Charge to Panel – Question 7

Assessing Long-Range Transport 

7.	Screening for Long-Range Transport Potential.  For some pesticides
with PBT characteristics, long-range transport (i.e., transcontinental
and intercontinental transport) has been well documented.  Currently,
OPP’s ecological risk assessment process relies heavily on monitoring
data for assessing long-range transport concerns.  However, this process
does not a priori screen for long-range transport potential prior to
pesticide release in the environment.  Difficulties in linking local use
patterns of pesticides to far-field (e.g., intercontinental) deposition
and exposure in a modeling framework is considered a major challenge in
screening and assessing long-range transport potential.

Please comment on the strengths and limitations of available tools for
screening the long-range transport potential of pesticides (e.g., the
OECD screening tool for long-range transport). 

4:15 P.M.	Charge to Panel – Question 8

Cross-Cutting Questions 

8. 	PBT Risk Assessment Issues:  In this White Paper, the Agency
describes a number of issues associated it has encountered when
assessing persistence, bioaccumulation, toxicity and long-range
transport in its aquatic and terrestrial ecological risk assessments
involving pesticides with PBT profiles.  In addition, the Agency has
identified various methods and approaches that it is considering for
refining its ecological risk assessment process specifically to address
these PBT and LRT-related issues.  Please comment on:

The extent to which the Agency has identified and characterized the
unique or problematic issues associated with assessing ecological risks
of pesticides with PBT characteristics,

The need for the Agency to incorporate refinements in the tools and
methods it uses to assess ecological risks of these compounds

5:30 P.M.	Adjournment

AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)

	OPEN MEETING

	

October 28 - 31, 2008

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket Number: EPA-HQ- OPP-2008-0550

U.S. Environmental Protection Agency

Conference Center - Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202

Selected Issues Associated with the Risk Assessment Process for
Pesticides with Persistent, Bioaccumulative and Toxic Characteristics

Please note that all times are approximate (see note at end of Agenda).

Friday, October 31, 2008

8:30 A.M.	Opening of Meeting - Administrative Procedures by Designated
Federal Official - Myrta Christian, M.S., Designated Federal Official,
Office of Science Coordination and Policy, EPA

8:35 A.M.	Introduction and Identification of Panel Members - 

		Steven G. Heeringa, Ph.D., FIFRA Scientific Advisory Panel Chair

8:50 A.M. 	Follow-up from Previous Day’s Discussion – Donald Brady,
Ph.D., 			Division Director, Environmental Fate and Effects Division,
Office of 			Pesticide Programs, EPA

9:15 A.M.	Charge to Panel – Question 9

9. 	Example Pesticide Assessments. In this White Paper, the Agency
provides examples of how it has assessed the environmental persistence,
bioaccumulation, toxicity and long-range transport of several
unidentified pesticides using refinements to its ecological risk
assessment methods.  Given the data available, as illustrated in the
pesticide examples provided in the White Paper, please comment on:

Whether the Agency has used these data appropriately to the fullest
extent possible in assessing ecological risks of pesticides with PBT
characteristics

Methods it has used to characterize environmental persistence,
bioaccumulation, toxicity and long-range transport potential of the
example pesticides.

10:15 A.M.	Break

10:30 A.M.	Charge to Panel - Question 10

Future PBT-Related Refinements 

10.	The Agency is considering refinements to its problem formulation
process to improve the ecological risk assessment of pesticides with PBT
characteristics, as outlined in Chapter 8 of the White Paper.   In
particular, please comment on: 

The Agency’s proposed process for identifying (screening) pesticides
for potential PBT risk assessment issues that need to be addressed  

The priority for developing new models, methods, and information for
addressing PBT issues. 

11:30 A.M.	Adjournment

Please be advised that agenda times are approximate; when the discussion
for one topic is completed, discussions for the next topic will begin. 
For further information, please contact the Designated Federal Official
for this meeting, Myrta R. Christian, M.S., via telephone: (202)
564-8498; fax: (202) 564-8382; or email: christian.myrta@epa.gov

`

 PAGE   

 PAGE   7