UNITED STATES ENVIRONMENTAL PROTfCTION AGENCY
WASHINGTON, 0,C. 20460
EPA-SAB-RAC-COM-92-002 January 9, 1992
Honorable William K. Reilly
Administrator • omceoF
U.S. Environmental Protection Agency THE ADMINISTRATOR
401 M Street, S.W.
Washington, D,C. 20460
Subject.- Commentary on Residual Radioactivity
Dear Mr. Reilly:
Upon the recommendation of its Radiation Advisory Committee, the Science
Advisory Board urges the Agency to develop Federal radiation protection guidance
specifically for removal or remediation actions for radioactive substances at various
locations, including Superfund sites and Federal facilities. No radiation guidance
directed to allowable residual radioactivity contamination at such sites currently
exists. This recommendation is directed toward residual radioactivity resulting
from human activities, not naturally occurring distributions of radionuclides.
The present guidelines available for assessing cancer risk focus mainly on
chemical contamination at Superfund sites. These use risk-based goals frequently
augmented by reference to Applicable Relevant and Appropriate Requirements
(ARARs), which are specific numerical guidelines derived from regulatory limits
used elsewhere. For radioactive substances ARARs either do not exist or were
developed for purposes distinctly different from those contemplated for residual
radioactivity.. For example, the Agency commonly selects a radionuclide standard
for finished drinking water to use as an ARAB for leachate or contaminated
groundwater at such sites; this practice imposes an unnecessarily high restriction
in areas wherein such water is not being used for human consumption.
Both the Department of Energy and the Superfund program must deal with
radioactive contaminants at more than a hundred sites of various types. The
number is likely to increase, perhaps substantially, as federal site evaluations
proceed, and as radioactivity sources not previously considered gain public
attention. Examples of this latter category are accumulation of naturally occurring
radioactive materials in wastes from oil drilling and pipeline activities and in
municipal water treatment residues. The Congress has recognized this potential
problem by directing the Agency to address this issue in a recent appropriation
bill. The Agency previously issued an Advance Notice of Proposed Rule-Making
for residual radioactivity in 1986 (51 FR 22264) but the Agency has made little
progress in finalizing this notice.
PrmltdOn &ic\c.
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States and Federal agencies do not now have specific criteria for residual
radioactivity to follow in assessing sites, or for designing and implementing
remedial actions. This lack of clearly defined and consistent requirements leads to
considerable variation in approach from site to site and, at times, selection of
costly clean-up procedures that may not be justifiable from a cost/risk point of
view.
The technical issues that should be considered in developing guidance
should include at least the following:
1. the types and forms of radioactive substances at sites;
2, a consistent protocol for exposure assessment and risk estimation that
recognizes both spatial and temporal factors and the attendant uncertainties
associated with human exposures to radiological contaminants at or from these
sites;
3, the digree to which other contaminants and biota may enhance or
inhibit the on-site and off-site migration of radionuclides; and
4. consideration of technical approaches for implementation of guidelines
through managing radionuclide contaminants, and the effectiveness, costs, and
cost/risk balancing for selected remedial actions.
Such guidance could include residual contamination levels for individual
radionuclides that should not be exceeded, or perhaps set forth decision-making
processes for establishing such levels. Current Suparfund guidance suggests that
any lifetime risk in excess of one in ten thousand is an obligatory (de maximus)
basis for consideration of the feasibility of removal or remediation action. • Once an
action has begun, the risk goal may be as low as one in a million, which may
represent a de minimis level for which no further action is indicated. However,
the radiation exposures that would produce such risks are far below variations in
the natural background level. Measurement of the corresponding nuclide
concentrations is difficult and the reliable estimation of the net effects independent
of natural background is difficult if not impossible to verify. The Agency thus
must establish whether the de maximus and dejtninimis values used for Superfund
actions for chemicals are justified for radionuclides as well, and if it is determined
that these levels are not justified, such values and ARARs for radionuclides must
be established.
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The Board will continue to follow the Environmental Protection Agency's
progress on residual radioactivity. We shall be happy to elaborate on the need for
Federal guidance at your convenience. We look forward to hearing your thoughts
on an approach to this important issue.
Sincerely,
Raymond C. Loehr, Chair
Executive Committee
Science Advisory Board
Oddvar F. Nygaard, Chair
Radiation Advisory Committee
Enclosure; Committee roster
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U.S. ENVIRONMENTAL PROTECTION AGENCY
SCIENCE ADVISORY BOARD
RADIATION ADVISORY COMMITTEE
ROSTER
CHAIRMAN
Dr. Oddvar F. Nygaard
Division of Biochemical Oncology
Department of Radiology
University Hospitals of Cleveland
2058 Abington Road
Cleveland, Ohio 44106
MEMBERS
Dr. Kelly H. Clifton
Department of Human Oncology and Radiology
University of Wisconsin Clinical Cancer Center
K4/330, Clinical Science Center
600 Highland Avenue
Madison, Wisconsin 53792
Dr. James E. Martin
Assistant Professor of Radiological Health
University of Michigan
School of Public Health
Ann Arbor, Michigan 48109
Dr. Genevieve M. Matanoski .
Professor of Epidemiology
The Johns Hoplcins University
School of Hygiene and Public Health
Department of Epidemiology
524 North Broadway, Room 280
Baltimore, Maryland 21205
Dr. H. Robert Meyer
C.N.S.I.
750 East Park 'Drive
Suite 200.
Harrisburg, Pennsylvania 17111
Dr. Richard G. Sextro
Building Ventilation and
Indoor Air Quality Program
Lawrence Berkeley Laboratory
Building 90, Room 3058
Berkeley, California 94720
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