ML20029B992
| ML20029B992 | |
| Person / Time | |
|---|---|
| Issue date: | 01/02/1990 |
| From: | NRC |
| To: | Carr K NRC COMMISSION (OCM) |
| Shared Package | |
| ML20029B990 | List: |
| References | |
| FOIA-90-415 NUDOCS 9103220141 | |
| Download: ML20029B992 (3) | |
Text
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= Note to Chairman Carr Steveqds\\/q Margyret,qph
SUBJECT:
SUMMARY
OF BEIR V PRESS CONFERENCE, DECEMBER 19, 1989 On Tuesday. December 19 I attended a press conterence by the National Research Council on the conclusions of the BEIR V (Biological Effects of Ionizing Radiation) Panel.
The Panel was chaired by Dr. Arthur Upton, who presented a brief summary statement and conducted a question and answer session that followed.
Dr. Upton was accompanied by several members of the Panel.
This note i
summarizes the Panel's remarks during the conference.
Dr. Upton characterized the BEIR V study as a comprehensive review of the risks associated with internal and external sources of radiation.
The Panel focused on risks associated with gamma, beta, neutron, and
-x-ray radiation; the BEIR IV_ Panel concluded its review of the risks associated with exposure to alpna radiat3on in 1988.
The BEIR V effort consisted of_8 formal meetings of the Panel and numerous
. subgroup meetings over a 30-month period.
The Panel solicited public
. comments at a meeting in_ March 1987.
Dr. Upton summarized the conclusions of the Panel as follows:
(1) Estimated risks of radie. tion-induced fatal cancers in-adults are-3 to 4 times higher than estimated in BEIR III.
(2) The risk of radiation-induced mental retardation in embryo / fetuses _is somewhat larger than previously estimated.
i (3) There are no demonstrable,' radiation-induced hereditary l
. effects in-survivors of the atomic bomb explosions; this conclusionLendorses the genetic risk estimates in BEIR III.
1Dr..Upton stated that the Panel's conclusions were based on more
- sophisticated dose / risk modeling than previously used and on reassessment'of the Hiroshima.and. Nagasaki; dosimetry.
He stated.that over the last decade more excess cancers have developed in the atom bomb survivors than had been predicted.
The increase in latent--
cancers-indicates a relative (or' multiplies +.ive ) risk model may be more appropriate for estimating ~ risk assocs3.ed with radiation dose.
6 Dr. Upton cautioned, however, that radiaticn induced cancer risks.
cannot-be estimated-using a' single model.
The Panel prefers:a l
combination approach employing-both the additive and multiplicative risk models to account _for-both:the. age at which exposure occurs and the time after exposure.
He noted that the BEIR VLrisk cancer estimates.are not significantly greater than those~of BEIR I,:which used'a multiplicative risk _model.-
He also noted that'the BEIR V risk-estimates are-bracketed by the risk _ estimates of the UNSCEAR 1988-
. study, which employed both' types of risk models.
Dr. Upton. stated That the public should not bo_ greatly concerned about the conclusions of BEIR V.
_Important lessons for members of rf theigeneral public from BEIR V include (1) scientists are-unsure g_
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BECKER 90-415 PDR l
whether there is a threshold below which humans incur no risk from radiation doses. (2) it is importan+- to estimate the risks at small doses of radiation and set radiation protection standards accordingly, (3) doses should be minimized, and (4) unnecessary doses should not be tolerated.
The first two points endorse the continued use of the no threshold, linear hypothesis in estimating risks and setting radiation protection standards.
His last two points embrace the concepts of optimization (ALARA) and justification of practice.
In response to repeated questions about whether radiation protecti,n standards would need to be reduced by 3 to 4 times because of the increase in risk estimates, Dr. Upton stated that the Panel did not examine the adequacy of radiation protection standards and that Federal agencies are responsible for making these decisions.
He commented that promulgation of standards involves a balancing of the risks and benefits that the Panel was not prepared or requasted to perform.
He steted that responsible agencies are currently reassessing the adequacy of existing radiation protection standards and that he personally expected some changes in the standards.
Other statements made by the Panel in response to questions during the conference included:
- Scientists will probably never know whether a dose threshold exists, below which no risk is incurred; standards need to be established to protect numans at the upper limit of risks.
- The National Research Council is conducting a study of nuclear l
utility workers to assess the occupationa' risk; the World Health Organization is performing a similar study that includes assessment of DOE health effects data.
Results from these studies should be released in 1990 or 1991.
- A dose over a long period of time is less effective, less risky-than the same dose in a short period of time.
- However, I
the Panel was unable to quantify the magnitude of this "dese rate effectiveness factor " which was estimated to be about 2.5 4
in BEIR III.
- Although individual risks at low doses may be insignificant.
y population riske for widespread exposure at the same doses may l
be significant.
This comment endorses consideration of collective doses.
- The Panel considered 10 rem to be a low dose because of the paucity of data at doses below 10 rem, which results in large uncertainties in risk estimates at the very low doses and dose rates typical of public exposures.
Based on the Panel's summary and remsrks at the conference. I do not expect that the BEIR V conclusions will significantly impact the Commission's activities because NRC has been using the more conservative UNSCEAR risk estimates in developing the technical bases for rules, policies, and regulatory guidance (e.g.,
BRC policy).
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=.-_
4 Nevertheless, we need to review the BEIR V report and assess its ramifications for NRC's programs.
The SRM on the Contaminated Materials Sites Cleanup Briefing (12/21/89) directs staff to conduct a preliminary assossment.
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