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V ^% v UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
1 WASHINGTON, D.C. 20460
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Septembur 29, 1995
CDA CAD CC(~ r*r™yi oc nnc ^ OFFICE OF THE ADMINISTRATOR
EPA-SAB-EEC-COM-95-005 *" SCIENCE ADVISORY BOARD
Honorable Carol M. Browner
Administrator
U.S. Environmental Protection Agency
401 M Street SW
Washington, DC 20460
SUBJECT: Commentary on Appropriateness of SAB Reviews of
Computer Environmental Transport and Fate Models
. Developed for Regulatory Decisionmaking
Dear Ms. Browner:
The Environmental Engineering Committee (EEC) of the Science Advisory Board
(SAB) presents this Commentary in order to clarify its role as peer reviewer of new and
modified computer models developed by the Agency. Specifically, the EEC plans to
focus on the peer review of the following:
a) Substantially new models;
b) Technically significant advances/adaptations of existing models;
c) Novel and/or controversial applications of existing models; and
d) Situations in which applications of models could have significant impact on
major regulatory decisions.
The Committee will work with the Agency to identify those fundamental models and
model developments that should receive close scrutiny by the SAB. At the same time,
an even larger number of more evolutionary developments will be identified for review
by alternative peer review mechanisms. This type of distinction-with the SAB
maintaining a "right of first refusal"-was first envisioned ia the Board's favorable 1993
review of the Agency's proposed model review process (EPA-SAB-EEC-LTR-93-008,
July 1993).
The Environmental Engineering Committee has nearly a decade of experience in
reviewing computer transport and fate models for the Agency. This Commentary is a
result of that experience, including deliberations and discussions associated with the
EEC's most recent report: Review ofEPA's Composite Model forLeachate Migration,
Including Transformation Products (EPA-SAB-EEC-95-010, August 1995).
U.S. Environmental Protection Agency
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77 West Jackson Boulevard, 12tn Floor ry TN p*** <»,>«>«•«,« conu*i*
Chicago, IL 60604-3590
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In sum, the EEC continues to believe that mathematical models are important
tools for incorporating scientific understanding of environmental processes into
regulatory decisionmaking.
The EEC has rendered model-specific advice on several different computer
-transport and fate models. In addition, the Committee has offered generic advice (e.g.,
the Board's very first commentary-EPA-SAB-EEC-89-012) on how the Agency could
organize itself to review models-and improvements in models-in a more systematic
manner. Recently, the Committee favorably reviewed the Agency's generic approach
for conducting peer review of such models (EPA-SAB-EEC-LTR-93-008), which
includes reviewing the mathematical equations, verification processes, and real-world
applications of models for regulatory decisions. In an associated action, the Agency
has moved forward with the implementation of the Agency's Peer Review Policy for all
majqr scientific and technical workproducts (issued in July, 1994), including computer
models.
In light of these developments and the increasing number of alterations in and
applications of existing models, the EEC perceives its future institutional role as
focusing on the peer review of the following:
a) Substantially new models.
b) Technically significant advances/adaptations of existing models.
c) Novel and/or controversial applications of existing models.
d) Situations in which applications of models could have significant impact on
major regulatory decisions.
Other matters related to models are likely to be more incremental and evolutionary in
nature and should be reviewed through other mechanisms described in the Peer
Review Policy.
For the next several months, the Committee would like to work with the Agency
in making these distinctions. Such an exercise would enable the SAB and the Agency
to generate a common understanding of the types of issues that should come to the
Board and those that should be handled by some other mechanism.
In addition, the Committee would like to be kept informed of--and, as warranted,
provide advice on-the process and progress of the alternative peer review mechanisms
established for models.
In short, the EEC compliments the Agency on the steps it has taken to respond
to recommendations concerning peer review of computer environmental transport and
fate models used in regulatory decisionmaking. The Committee will work with the
Agency to exercise those new mechanisms, while focusing EEC involvement on the
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most significant issues. At the same time, the EEC has a continuing commitment to
insuring that there is adequate and appropriate peer review of major changes/
applications of such models.
The Committee looks forward to working with the Agency on these issues and to
your reaction to the projected future role of EEC in peer review of computer models.
Sincerely,
-Til.
Dr. Genevieve M. Matanoski, Chair Dr. Ishwar P. Murarka, Chair
Executive Committee Environmental Engineering
Science Advisory Board Committee
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NOTICE
This report has been written as part of the activities of the Science Advisory
Board, a public advisory group providing extramural scientific information and advice to
the Administrator and other officials of the Environmental Protection Agency. The
Board is structured to provide balanced, expert assessment of scientific matters related
to problems facing the Agency. This report has not been reviewed for approval by the
Agency and, hence, the contents of this report do not necessarily represent the views
and policies of the Environmental Protection Agency, nor of other agencies in the
Executive Branch of the Federal government, nor does mention of trade names or
commercial products constitute a recommendation for use.
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t
V
U.S. ENVIRONMENTAL PROTECTION AGENCY
Science Advisory Board
Environmental Engineering Committee
CHAIR
Dr. Ishwar P. Murarka, Electric Power Research Institute, Palo Alto, CA
MEMBERS
Dr. Linda M. Abriola, Dept. of Civil and Environmental Engineering, University of Michigan,
Ann Arbor, MI
Dr. Calvin C. Chien, duPont Company, Corporate Remediation, Wilmington, DE
Dr. Hilary I. Inyang, Department of Civil Engineering, University of Massachusetts, Lowell, MA
Dr. James H. Johnson, Jr., School of Engineering, Howard University, Washington, DC
Dr. Wayne M. Kachel, Martin Marietta Corporation, Oak Ridge, TN
Dr. Jo Ann Lighty, Department of Chemical and Fuels Engineering, University of Utah, Salt
Lake City, UT
Dr. James W. Mercer, GeoTrans, Inc., Sterling, VA
Dr. Frederick G. Pohland, Department of Civil and Environmental Engineering, University of
Pittsburgh, Pittsburgh, PA
Dr. Robert B. Pojasek, Cambridge Environmental, Inc., Cambridge, MA
Dr. Wm. Randall Seeker, Energy & Environmental Research Corp., Irvine, CA
SCIENCE ADVISORY BOARD STAFF
Mrs. Kathleen W. Conway, Designated Federal Official, U.S. EPA, Science Advisory Board,
401 M Street, SW (HOOF), Washington, DC 20460
Mrs. Dorothy M. Clark, Staff Secretary, U.S. EPA, Science Advisory Board, 401 M Street, SW
(HOOF), Washington, DC 20460
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