                                PUBLIC AGENDA 
                     FIFRA SCIENTIFIC ADVISORY PANEL (SAP)
                                 OPEN MEETING
                              October 25-26, 2011
                                       
              FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/
                     OPP Docket Telephone: (703) 305-5805
                     Docket Number: EPA-HQ- OPP-2011-0582
                                       
                     U.S. Environmental Protection Agency
                         Conference Center Lobby Level
                        One Potomac Yard (South Bldg.)
                  2777 S. Crystal Drive, Arlington, VA 22202
                                       
The Two-dimensional Exposure Rainfall-Runoff Assessment (TERRA) Watershed Model and its Use in the FIFRA Ecological Risk Assessment for Antimicrobial Uses of Copper 
                                       
Please note that all times are approximate (see note at end of Agenda).

Tuesday, October 25, 2011

9:00 A.M. 	Opening of Meeting and Administrative Procedures
            Dr. Fred Jenkins, Designated Federal Official, Office of Science Coordination and Policy (OSCP, EPA)
            
9:05 A.M. 	Introduction and Identification of Panel Members
      Dr. Kenneth Portier, Chair, FIFRA Scientific Advisory Panel

9:15 A.M. 	Welcome and Opening Remarks
      Dr. Steven Bradbury, Director, Office of Pesticide Programs (OPP, EPA) 
            
9:30 A.M. 	Introduction to the Office of Pesticide Program's Environmental Exposure Modeling and Assessment
		Dr. James Hetrick and Dr. Siroos Mostaghimi (OPP, EPA)

10:30 A.M. 	Break 

10:40 A.M. 	Overview of the Two-dimensional Exposure Rainfall-Runoff Assessment (TERRA) Model
		Dr. Mark Velleux, American Chemical Council (ACC)

12:10 P.M. 	Lunch 



1:10 P.M. 	Overview of the Two-dimensional Exposure Rainfall-Runoff Assessment (TERRA) Model (Cont'd)

1:30 P.M. 	TERRA Model as Applied to the Antimicrobial Copper Risk Assessment
	Dr. Mark Velleux (ACC)

2:50 P.M.	 Break

3:05 P.M.	EPA's Review of TERRA Model as Applied to the Antimicrobial Copper Risk Assessment 
		Dr. Stephen Wente (OPP, EPA)

3:30 P.M.	Public Comment 

4:30 P.M.	Presentation of Charge Questions 
		Donna Randall (OPP, EPA)

Discussion of Charge Questions

Charge Question 1

The three most prevalent antimicrobial uses of copper include antifoulant paints, roofing shingles
and wood preservatives. The Antimicrobials Division used a basic field scale modeling
approach, including maximum use rates, realistic heavy rainfall events, the assumption of high
leaching rates, and storm-water conveyance via impervious surfaces, to estimate potential high
end aquatic exposure from copper's use as an antimicrobial pesticide in roofing shingles and
treated wood. The American Chemistry Council (ACC) has proposed the TERRA Model as an
alternative and more refined way to assess aquatic exposure due to the two major urban
antimicrobial uses of copper, in wood preservatives and in roofing shingles, on a watershed scale
level.

a) What does the Panel believe are the advantages and/or limitations of assessing
antimicrobial uses of copper from roofing shingles and wood preservatives with TERRA, a
spatially-explicit, watershed scale model? Are there other models that the Panel feels
should be considered for use by OPP in estimating exposure to copper from its use as an
antimicrobial pesticide, specifically in roofing shingles and wood preservative?

b) In the opinion of the Panel, what attributes of an urban watershed model are the most
critical and why does the Panel regard these attributes as critical? Does the TERRA model
possess these attributes?

5:30 P.M.	ADJOURN 





Wednesday, October 26, 2011
9:00 A.M.	Opening of Meeting and Administrative Procedures 
            Dr. Fred Jenkins, Designated Federal Official, Office of Science Coordination and Policy, EPA

9:05 A.M.	Introduction and Identification of Panel Members
      Dr. Kenneth Portier, Chair, FIFRA Scientific Advisory Panel

9:15 A.M.	Discussion of Charge Questions 

Charge Question 1 (Cont'd)

c) Please discuss whether TERRA has the modeling capabilities necessary for it to be applied
to other urban metal exposure assessments for antimicrobial pesticides as well as what
modifications, if any, would be needed to assess exposure to other metals used as
pesticides.

d) In the opinion of the Panel what further development and/or assessment is necessary to
prepare the TERRA model for use as an exposure assessment tool by the EPA?

11:00 A.M.	Break 

11:10 A.M.	Discussion of Charge Questions (Cont'd)

Charge Question 2

EPA employs a tiered strategy to assess aquatic exposure. The first tier facilitates the rapid
screening of pesticide uses for potential risk issues, while the second tier refines exposure
estimates by utilizing a field scale model and site specific properties. This process is designed to
incorporate additional data (e.g., site specific properties) for each progressive tier. EPA has
historically employed field scale models to assess aquatic exposure in support of national
pesticide registrations. The TERRA model, unlike other models used by OPP, is a fully
distributed, spatially-explicit watershed model. It has model capabilities of distributing
differences in hydrology, meteorology, soil properties, and pesticide uses across a watershed.
These model capabilities require consideration in terms of the proper scale of the exposure
assessment.

a) Are the appropriate pathways (e.g. engineered water conveyance structures) for modeling
urban antimicrobial uses of copper within the Goodwin Creek scenario currently included
in the framework of the TERRA model? What, if any, additional pathways are necessary
to appropriately estimate exposure concentrations?


12:00 P.M.	Lunch

1:00 P.M.	Discussion of Charge Questions (Cont'd)

Charge Question 2 (Cont'd)

b) What are the most important attributes to consider when selecting and designing an urban
watershed modeling scenario? In the opinion of the Panel, where does the Goodwin
Creek watershed fall within a distribution of the nation's urban watersheds? Also, given
that the model does not account for storm drains, how does this compare to watersheds
nationwide?

1:45 P.M.	Discussion of Charge Questions (Cont'd)

Charge Question 3

Watershed-scale models require calibration to account for complex watershed-dependent
hydrology and environmental fate processes. Model calibrations have been conducted by
altering saturated hydraulic conductivity, Mannings N, soil erodibility factors, land cover factors,
and chemical partitioning coefficients. In contrast, the OPP field-scale models such as
PRZM/EXAMS are not calibrated for site-specific hydrology, etc.
The TERRA model utilizes a simulated urban watershed that was calibrated to the hydrology and
sediment loads of Goodwin Creek. Because the Goodwin Creek watershed is a predominately
pastured/forested watershed, the EPA has concerns that the calibration processes may not
adequately represent urban hydrologic and chemical transport processes.

a) Please discuss the implications of watershed land use patterns on model calibration.
What types of impacts could these have on the estimated exposure concentrations of
copper?

3:15 P.M.	Break

3:30 P.M.	Discussion of Charge Questions (Cont'd)

Charge Question 3 (Cont'd)

b) Please indicate any unique calibration issues that should be considered when simulating
an urban, residential watershed.

5:00 P.M.	ADJOURN 

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, Dr. Fred Jenkins, via telephone: (202) 564-3327; fax: (202) 564-8382; or email: jenkins.fred@epa.gov.




