SEPTEMBER 9-10, 2004 Meeting Agenda

September 02, 2004

AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)
OPEN MEETING
SEPTEMBER 9 - 10, 2004
FIFRA SAP WEB SITE https://www.epa.gov/scipoly/sap/
OPP Docket Telephone: (703-305-5805)
Docket Number: OPP-2004-0242

THURSDAY, SEPTEMBER 9, 2004
Holiday Inn - National Airport
2650 Jefferson Davis Highway
Arlington, VA 22202
Telephone: (703-684-7200)

Fumigant Bystander Exposure Model Review: SOil Fumigant Exposure Assessment System (SOFEA©) Using Telone as a Case Study

• 8:30AM Introduction and Identification of Panel Members - Steven Heeringa, Ph.D. (FIFRA SAP Session Chair)
• 8:45 AM Administrative Procedures by Designated Federal Official - Mr. Joseph E. Bailey
• 8:50 AM Welcome - Mr. Joseph J. Merenda, Jr. (Director, Office of Science Coordination and Policy)
• 8:55 AM Introduction and Opening Remarks - Randolph Perfetti, Ph.D. (Office of Pesticide Programs)
• 9:00 AM Goals and Objectives - Mr. Jeffrey Dawson (Office of Pesticide Programs, EPA)
• 9:15 AM SOil Fumigant Exposure Assessment System (SOFEA©) - Steven A. Cryer, Ph.D. (Dow AgroScience, LLC), Ian van Wesenbeeck, Ph.D. (Dow AgroSciences, LLC), and Bruce A. Houtman, CIH (Dow AgroSciences, LLC)
• 10:15 AM BREAK
• 10:30 AM SOil Fumigant Exposure Assessment System (SOFEA©) - Steven A. Cryer, Ph.D. (Dow AgroScience, LLC), Ian van Wesenbeeck, Ph.D. (Dow AgroSciences, LLC), and Bruce A. Houtman, CIH (Dow AgroSciences, LLC)\
• 12:00 AM LUNCH
• 1:00 PM Public Comments
• 2:00 PM Panel Discussion

Critical Element 1: Documentation

Question 1: The background information presented to the SAP panel by the SOFEA developers provides both user guidance, a technical overview of the system, and a series of case studies.
(A) Please comment on the detail and clarity of these documents.
(B) Are the descriptions of the specific model components accurate?
(C) Do the algorithms in the annotated code perform the functions as defined in this document?
(D) Please discuss any difficulties encountered with respect to loading the software and evaluating the system including the presented case study.

• 3:00 PM BREAK
• 3:15 PM Panel Discussion (continued)

Critical Element 2: System Design/Inputs

Question 2: In the background documents, a series of detailed individual processes and components included in SOFEA are presented. The key processes include (1) incorporation of ISCST3 into SOFEA, (2) probabilistic scaling of flux rates; (3) defining source placement within an airshed; (4) development of receptor grids within airsheds; and (5) generation of probability distribution functions based on use patterns and application parameters.
(A) Please comment on these proposed processes, the nature of the components included in SOFEA and the data needed to generate an analysis using SOFEA.
(B) Are there any other potential critical sources of data or methodologies that should be considered?

• 4:30 PM ADJOURNMENT
FIFRA SCIENTIFIC ADVISORY PANEL (SAP)
OPEN MEETING
SEPTEMBER 9 - 10, 2004
FIFRA SAP WEB SITE https://www.epa.gov/scipoly/sap/
OPP Docket Telephone: (703-305-5805)
Docket Number: OPP-2004-0242

FRIDAY, SEPTEMBER 10, 2004
Holiday Inn - National Airport
2650 Jefferson Davis Highway
Arlington, VA 22202
Telephone: (703-684-7200)

Fumigant Bystander Exposure Model Review: SOil Fumigant Exposure Assessment System (SOFEA©) Using Telone as a Case Study

• 8:30AM Introduction and Identification of Panel Members - Steven Heeringa, Ph.D. (FIFRA SAP Session Chair)
• 8:35 AM Administrative Procedures by Designated Federal Official - Mr. Joseph E. Bailey
• 8:40 AM Follow-up from Previous Day’s Discussion - Mr. Jeffrey Dawson (Office of Pesticide Programs)
• 9:00 AM Panel Discussion (continued)

Question 3: The determination of appropriate flux/emission rates is critical to the proper use of the SOFEA model as these values define the source of fumigants in the air that can lead to exposures. Upon its review of how flux rates can be calculated, the Agency has identified a number of questions it would like the panel to consider. In SOFEA, measured flux rates specific to the conditions at the time of the monitoring studies used are adjusted based upon incorporation depth and seasonal differences to account for varying application conditions. Emissions of 1,3-dichloropropene are sensitive to soil temperature and incorporation depth. Incorporation depth is addressed using the EPA model PRZM3 and also the USDA model CHAIN-2D. Scaling factors were used to address temperature differences.
(A) What, if any, refinements are needed for this process including the manner in which flux values were directly monitored and calculated using the aerodynamic flux approach? (B) SOFEA can easily be modified to probabilistically vary flux rate for each application based on variability in field flux measurements (e.g., application method or temperature) or model generated flux. Please comment on this potential modification.
(C) How appropriate is it to use a flux/emission factor from a single monitoring study (or small number of studies) and apply it to different situations such as for the same crop in a different region of the country?
(D) Please comment on SOFEA’s capability to adequately consider multiple, linked application events on an airshed basis as well as single source scenarios.
(E) Does SOFEA appropriately address situations where data are missing?

• 10:30 AM BREAK
• 10:45 AM Panel Discussion (continued)

Question 4: The integration of meteorological data into ISCST3 is one of the key components that separates the SOFEA methodology from that being employed by the Agency in its current assessment. This information, coupled with GIS (Geographical Information Systems) data such as the amount of ag-capable land cover, elevation, and population densities are optional inputs for SOFEA.
(A) Can the panel comment on the value of adding this information for conducting spatially realistic simulations?
(B) There are several potential sources of meteorological and GIS data (e.g., National Weather Service and California Irrigation Management Information System or CIMIS). Please comment on the methods used to select these data including locations for meteorological stations.
(C) What criteria should be used to identify airsheds for analysis and how should data be selected to address each airshed? Please comment on the manner in which these data are processed.
(D) Data quality and uncertainty associated with these data vary with the source. Does the panel agree with the approaches used to characterize these factors?
(E) Anemometer sampling height has been identified as a concern by the Agency in preparation for this meeting. What are the potential impacts of using data collected with different anemometer heights in an analysis of this nature?
(F) Does SOFEA treat meteorological stability class inputs appropriately?
(G) Does SOFEA appropriately calculate bounding air concentration estimates?

• 12:00 AM LUNCH
• 1:00 PM Panel Discussion

Question 5: The Agency model, ISCST3 is critical component of the SOFEA approach. This model has been peer reviewed and is commonly used for regulatory purposes by the Agency. SOFEA also uses other Agency systems such as PCRAMMET and PRZM3 as well as the USDA model CHAIN-2D.
(A) Please recommend any parameters that should be altered to optimize the manner that they are used in SOFEA.
(B) ISCST3, as integrated into SOFEA, was run in regulatory mode which includes the use of the “calms” processing routine. Does the panel concur with this approach? If not, please suggest a suitable alternative.

Critical Element 3: Results

Question 6: Soil fumigants can be used in different regions of the country under different conditions and they can be applied with a variety of equipment.
(A) Please comment on to what extent the methodologies in SOFEA can be applied generically in order to assess a wide variety of fumigant uses? What considerations with regard to data needs and model inputs should be considered for such an effort?

• 2:30 PM BREAK
• 2:45 PM Panel Discussion (continued)

Question 7:
(A) Please comment on whether SOFEA adequately identifies and quantifies airborne concentrations of soil fumigants that have migrated from treated fields to sensitive receptors.
(B) The Agency is particularly concerned about air concentrations in the upper ends of the distribution. Are these results presented in a clear and concise manner that would allow for appropriate characterization of exposures that could occur at such levels?
(C) Please comment on SOFEA’s approach for calculating and presenting probability distributions of moving average concentrations for differing durations of exposure.
(D) Please comment on the types of monitoring data that would be required to define the accuracy of simulations made with SOFEA for differing durations of exposure.

Question 8:
(A) What types of sensitivity/uncertainty analyses of SOFEA are recommended by the panel to be the most useful in making scientifically sound, regulatory decisions?
(B) What should be routinely reported as part of a SOFEA assessment with respect to inputs and outputs? Are there certain tables and graphs that should be reported?
(C) Does the panel recommend any further steps to evaluate SOFEA and if so, what?
(D) SOFEA uses a Monte Carlo based approach based on varied random number streams for each simulation. Can the panel comment on the appropriate statistical techniques that should be used to define differences between outputs for different scenarios?

• 4:30 PM ADJOURNMENT

Please be advised that agenda times are approximate. For further information, please contact the Designated Federal Official for the meeting, Joseph E. Bailey, via telephone: (202) 564-8450; fax (202) 564-8382; or email: bailey.joseph@epa.gov

SEPTEMBER 9-10, 2004 Meeting Agenda

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