NRC comments on FGR-13 & EPA replies

["Tsurikov, Nick" <ntsuriko@rgc.com.au>]

>Dear Radsafers,

>In case you missed it:
>Five NRC comments on the EPA FGR-13 were posted on the EPA website some
time ago.
>The discussion in regards to the LNT hypothesis in presented in point
three:
>>>>>>>>>>>>>>>>>>>>>>
>NRC Comment 3:
>NRC, as well as many within the scientific community, is concerned that
the
>uncertainties associated with estimating risks from radiation at low
doses and low
>dose rates are significant, and that there is significant disagreement
among scientists
>regarding the magnitude of the actual health effects at these levels.
This scientific
>uncertainty occurs because evidence of radiation dose health effects
has only been
>observed at high dose levels and dose rates and significant uncertainty
is introduced
>when extrapolating to estimate the health effects at very low dose
levels and dose
>rates. NRC believes that because the FGR has radiogenic risks that are
expressed as
>"mortality or morbidity per becquerel," as Tables 2.3a and 2.3b state,
there is an
>implied scientific certainty down to these minute levels, when, in
fact, there is
>substantial uncertainty and lack of reliability.
>>>>>>>>>>>>>>>>>>>>>
>EPA Response: 
>The comment appears to question use of the linear no-threshold
hypothesis for
>estimating the carcinogenic effects of radiation. 
>We believe there is a strong scientific consensus that
>this approach is appropriate as the basis for decisions for protection
of 
>the public from most carcinogens, including radiation. 
>The purpose of FGR 13 is to assist such decisions. 
>This approach is endorsed for the specific case of radiation by the
National 
>Academy of Sciences, ICRP, National Council on Radiation Protection 
>and Measurements, United Nations Scientific Committee on the
>Effects of Atomic Radiation, EPA's Science Advisory Board, 
>and many other groups. We find no scientific or public policy basis for

>departure from this approach. (We note also that the NRC
explicitly endorsed this approach in the latest revision of its basic
standards 
>for protection against radiation (56 FR 23360, May 21, 1991).)

>Kind regards
>Nick Tsurikov
>Radiation Safety Officer
>RGC Mineral Sands, Eneabba, Western Australia
>ntsuriko@rgc.com.au
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