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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