AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)

OPEN MEETING

May 12-15, 2009

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

OPP Docket Telephone: (703) 305-5805

Docket Number: EPA-HQ-OPP-2009-0104

U.S. Environmental Protection Agency

Conference Center - Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202

Scientific Issues Associated with The Ecological Significance of

Atrazine Effects on Primary Producers in Surface Water Streams in the
Corn

and Sorghum Growing Region of the United States (Part II)

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

Tuesday, May 12, 2009

 

  9:00 A.M.	Opening of Meeting and Administrative Procedures –
Sharlene Matten, Ph.D., Designated Federal Official, Office of Science
Coordination and Policy, EPA

  9:10 A.M. 	Introduction and Identification of Panel Members – Steven
Heeringa, Ph.D., FIFRA Scientific Advisory Panel Chair, Daniel Schlenk,
Ph.D., FIFRA Scientific Advisory Panel Session Chair

  9:20 A.M.	Welcome and Opening Remarks – Steven Bradbury, Ph.D.,
Deputy Director, Office of Pesticide Programs (OPP), EPA 

  9:30 A.M.	Goals and Objectives – Donald Brady, Ph.D., Director,
Environmental Fate and Effects Division (EFED), OPP, EPA

  9:40 A.M.	Introduction and Background – Mark Corbin, M.S., Senior
Environmental Scientist, EFED, OPP, EPA

10:10 A.M.	BREAK

10:25 A.M.  	Method for Assessing Ecological Levels of Concerns for
Atrazine Exposures in Freshwater Systems – Russell Erickson, Ph.D.,
Research Chemist, Mid-Continent Ecology Division, Office of Research and
Development, EPA

12:00 P.M.	LUNCH 

 1:00  P.M.	Analysis of the AEEMP: Characteristics and Extent of
Watersheds that Exceed the Atrazine LOC – Nelson Thurman, M.S., Senior
Science Advisor, EFED, OPP, EPA

  2:15 P.M.	Examination of an Approach for Translating Plant Assemblage
Toxicity Index Risk Factors into Water Quality Criteria Concentrations
– Charles Delos, M.S., Environmental Scientist, Health and Ecological
Criteria Division (HECD), Office of Science and Technology (OST), Office
of Water (OW), EPA 

 2:45 P.M.	BREAK

 3:00 P.M.  	PUBLIC COMMENTS

 5:30 P.M.     ADJOURN	 



AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)

OPEN MEETING

May 12-15, 2009

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

OPP Docket Telephone: (703) 305-5805

Docket Number: EPA-HQ-OPP-2009-0104

U.S. Environmental Protection Agency

Conference Center - Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202

Scientific Issues Associated with The Ecological Significance of

Atrazine Effects on Primary Producers in Surface Water Streams in the
Corn

and Sorghum Growing Region of the United States (Part II)

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

Wednesday, May 13, 2009

  9:00 A.M.	Opening of Meeting and Administrative Procedures 

Sharlene Matten, Ph.D., Designated Federal Official, Office of Science
Coordination and Policy, EPA 

  9:05 A.M. 	Introduction and Identification of Panel Members 

	Daniel Schlenk, Ph.D., FIFRA Scientific Advisory Panel Session Chair

  9:15 A.M.    PUBLIC COMMENTS Cont’d

10:15 A.M.	BREAK 

10:30 A.M.	PUBLIC COMMENTS Cont’d 

12:00 P.M.	LUNCH

  1:00 P.M. 	CHARGE TO PANEL: Model Effects Index (MEI) (Questions 1-3)

The foundation of the US EPA methodology for specifying levels of
concern (LOCs) for atrazine exposures in natural freshwater systems is
the relationship of atrazine exposure to effects on aquatic plant
community structure and function in microcosm and mesocosm (cosm)
studies.  Comparing effects among the different atrazine exposure
time-series in the cosm studies and extrapolating effects to other
exposure time-series in natural systems requires an effects model that
can be applied to any exposure time-series to provide a consistent,
quantitative index for toxic effects on the plant community (Model
Effects Index, MEI).  MEI values for cosm exposures are used to develop
an LOC for the MEI (LOCMEI) that best discriminates between cosm
exposures with and without significant effects.  MEI values for
exposures in natural systems can then be evaluated relative to this
LOCMEI.  

Question 1:  The effects models considered in this document require
effects concentrations (ECs) from single-species plant toxicity tests
with atrazine that are consistent with respect to the nature and
magnitude of the toxic effects.  Reports on and reviews of such tests
provide ECs that vary widely in meaning, so a new review was conducted
and test results were used to develop a compilation of plant specific
growth rate vs. concentration relationships (Section IV.B).  Please
comment on the strengths and limitations of this review and synthesis of
plant toxicity tests for providing toxicity sensitivity distributions
for use in the atrazine assessment methodology.

  2:30 P.M.	BREAK

  2:45 P.M.	CHARGE TO PANEL: QUESTION 2

Question 2:  One source considered for the desired MEI is the
Comprehensive Aquatic Systems Model (CASM), a community simulation
model.  In response to a previous SAP review, this model was modified to
give a more realistic, dynamic simulation of a Midwestern stream
(CASMATZ2).  Sensitivity analyses for this revised model were conducted,
including some additional analyses suggested in the previous SAP review.
 These analyses indicated considerable sensitivity of risk
determinations to the selection of species toxicity parameters and to
various physicochemical variables (Section IV.C).  This indicates that
CASMATZ2 is more suitable for a site-specific, data-intensive assessment
than the generic application that is desired for these atrazine
assessments.  Please comment on the advisability and value of using
CASMATZ2 for generic assessments given these findings and on the nature
and feasibility of additional development efforts that would be needed
to implement this model.

  4:00 P.M.	CHARGE TO PANEL: QUESTION 3

Question 3:  An alternative source considered for the desired MEI was an
index of the severity of toxic impact on a plant assemblage (Plant
Assemblage Toxicity Index, PATI) based directly on single-species plant
toxicity relationships (Section IV.D).  Please comment on the merits and
limitations of this source for the MEI.  Based on the coherence of risk
evaluations between the PATI-based and the CASM-based methodologies, EPA
has concluded that the additional processes included in CASM are not
needed for the assessment methodology and that the PATI-based
methodology should be adopted.  Please comment on the merits of this
conclusion.  

  5:30 P.M.	ADJOURN



AGENDA

FIFRA SCIENTIFIC ADVISORY PANEL (SAP)

OPEN MEETING

May 12-15, 2009

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

OPP Docket Telephone: (703) 305-5805

Docket Number: EPA-HQ-OPP-2009-0104

U.S. Environmental Protection Agency

Conference Center - Lobby Level

One Potomac Yard (South Bldg.)

2777 S. Crystal Drive, Arlington, VA 22202

Scientific Issues Associated with The Ecological Significance of

Atrazine Effects on Primary Producers in Surface Water Streams in the
Corn

and Sorghum Growing Region of the United States (Part II)

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

Thursday, May 14, 2009

  9:00 A.M.	Opening of Meeting and Administrative Procedures 

Sharlene Matten, Ph.D., Designated Federal Official, Office of Science
Coordination and Policy, EPA 

  9:05 A.M. 	Introduction and Identification of Panel Members 

	Daniel Schlenk, Ph.D., FIFRA Scientific Advisory Panel Session Chair

  9:10 A.M. 	Follow-up from Previous Day’s Discussion 

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

  9:30 A.M.	CHARGE TO PANEL: Agency’s Watershed Analysis (Questions
4-5)

The Agency identified three sites that exceeded the PATI LOCMEI in
multiple years and six sites that exceeded the LOCMEI in one year
(Section V).  Based on the results of the Agency’s watershed analysis
in Section VI to identify additional sites that might exceed the
atrazine LOC, US EPA proposes two questions for the SAP:

Question 4: Based on an analysis of watershed characteristics of the 40
monitoring sites, the US EPA concluded that the presence of soils that
either have a high runoff potential or are in hydrologic soil group C or
D, and have a shallow layer with a moderately low saturated hydraulic
conductivity best distinguish sites that exceed the LOC in multiple
years from those that do not exceed the LOC.  Please comment on the
merits of the watershed criteria the Agency used to identify watersheds
that might exceed the atrazine LOC.  

10:30 A.M.	BREAK  

10:45 A.M.	Discussion of Charge Question 4 Cont’d

12:00 P.M.	LUNCH

  1:00 P.M.	CHARGE TO PANEL: QUESTION 5

Question 5: Neither atrazine use intensity or rainfall data (annual or
monthly) correlate positively with watersheds that exceed the LOC. The
Agency noted that the monitoring site selection already focused on areas
with sufficient atrazine use to potentially result in high atrazine
exposures in streams.  Please comment on the Agency’s proposed
approach to establish a minimum criteria for atrazine use intensity (>
0.1 lb ai/A) and rainfall (>23 inches annually).

  2:30 P.M. 	BREAK

  2:45 P.M.  	Panel Discussion

  5:30 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, Sharlene Matten, via telephone: (202) 564-0130; fax:
(202) 564-8382; or email: matten.sharlene@epa.gov

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