IJLJL 1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
I
'• „ WASHINGTON, D.C. 20460
April 27, 1988 SAB^MC-88-026
OFFICE OF
Honorable Lee Mi
Administrator
U* S. Environmental Protection. Agency
401 M Street, SW
Washington, B.C. 20460
Dear Mr. Thomas:
The purpose of this letter is to reiterate the Science Advisory Board
Radiation Advisory Committee's position on the use of the effective dose
equivalent concept of the International Commission on Radiological
Protection in deriving risk estimates and establishing regulations related
to exposures to humans from radionuelldes in the environment. Although
the Committee has recommended adoption of the effective dose equivalent
methodology during its review of EPA reports, the Agency has not been
consistent in its use of the effective dose equivalent concept or the
weighting factors applied in quantifying dose. More importantly, the
Radiation Advisory Committee is uncertain regarding the Agency's intentions
for Implementation of effective dose equivalent in the future,
As a specific example, the Radiation Advisory Committee undertook a
review of the Office of Drinking Water's Assessment of Radionuclides In
Drinking Water during 1987. One recommendation was "the documents should
include a clearer exposition of the basis for the risk estimates used,
the concept of effective dose equivalent and the weighting factors employed*
Although your letter of August. 21, 1987 in response to our review Indicated
the Agency would improve this aspect of the report, it did not definitively
outline how this would carried out. A briefing by a staff member from
the Office of Drinking Water also left the Committee wondering what the
Agency intended to do about this critical issue.
The Committee believes that effective does equivalent, rather than
dose equivalent to specific organs, should applied as the basis for
regulations dealing with radiation exposure. . The Radiation Advisory
Committee strongly1 encourages the Agency to examine carefully its position
on the effective dose equivalent concept, the numerical value of organ-
specific weighting factors, and the application of effective dose
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equivalent ia.iestabllshing regulations, with particular emphasis on insuring
consistency i^fctliin the EPA,, and between the Agency and other government,
national, and'international organizations. Weighting factors recommended
by the International Comnlssion on Radiological Protection should be
applied. This recommendation is entirely consistent with your Memorandum
for the President titled "Federal Radiation Protection Guidance for
Occupational Exposure" of January 27, 1987.
The Radiation Advisory Committee requests a formal response to this
letter and a summary of the Agency's findings and Intentions regarding
the use of effective dose equivalent in developing background information
documents and in setting radiation standards.
Sincerely,
Norton Nelson, Chairman
Executive Committee
Science Advisory Board
William J, Sehull,/Chairman
Radiation Advisoryxjoramittee
Science Advisory Board
cc: Richard Guimond, Director, Office of Radiation Programs
J. Craig Potter, Assistant Administrator for Air and Radiation
Michael Bt Cook, Director, Office of Drinking Water
Rebecca Hanmer, Acting Assistant Administrator for Water
Donald G» Barnes, Director, Science Advisory Board
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