Management of Commercially Generated Radioactive Waste - U.S. ...

E.1
APPENDIX E
RADIOLOGICALLY RELATED HEALTH EFFECTS
The radiation dose to man from ingestion, inhalation, or external exposure to specified
quantities of radionuclides can be calculated with reasonable confidence. Estimates of the
amounts of radioactive material that may be released from Commercial Waste Management (CWM)
operations, however, and fractions reaching man via various environmental pathways are not
as well defined. The relationship of dose to so-called "health effects" is even less well
defined. Thus, estimates of "health effects" that may result from radiation exposure con-
sequent to CWM activities can derive only from a chain of estimates of varying uncertainty.
The usual practice in making these estimates is that if an error is to be made, it will be
made in a way intended to overprotect the individual. As a result, if the chain of esti-
mates is long, there may be considerable conservatism in the final value.
Because expected releases of radioactive materials are small, and the radiation dose
to any individual is small, the effects considered are long-delayed somatic and genetic
effects; these will occur, if at all, in a very small fraction of the persons exposed.
Except as a consequence of the unusually severe accident involving larger doses, no possi-
bility exists for an acute radiation effect. The effects that must be considered are
1) cancers that may result from whole body exposures, and more specifically, from
radioactive materials deposited in lung, bone, and thyroid; and 2) genetic effects that are
reflected in future generations because of exposure of the germ cells.
Knowledge of these delayed effects of low doses of radiation is necessarily indirect.
This is because their incidence is too low to be observed against the much higher background
incidence of similar effects from other causes. Thus, for example, it is not possible to
attribute any specific number of human lung cancers to the plutonium present in everyone's
lungs from weapons-test fallout, because lung cancers are known to be caused by other mate-
rials present in much more hazardous concentrations, and because lung cancers occurred
before there was any plutonium. Even in controlled studies with experimental animals, one
reaches a low incidence of effect that cannot be distinguished from the level of effect in
unexposed animals, at exposure levels far higher than those predicted to result from CWM
activities. Hence, one can only estimate a relationship between health effect and radiation
dose, basing this estimate upon observations made at very much higher exposure levels, where
effects have been observed in man, and carefully studied animal experiments. In this con-
text the National Council on Radiation Protection and Measurements has said (NCRP 1975):
"The NCRP wishes to caution governmental policy-making agencies of the unreasonableness of
interpreting or assuming 'upper limit' estimates of carcinogenic risks at low radiation