N-5
The sequence of safety recommendations and guides has run as follows. |
(a) In 1954 the National Bureau of Standards Handbook 59 presented
the recommendations of the NCRP. The maximum permissible dose to the
bone marrow (and hence to the entirebody) was 0.3 rem per week.
(b) In January, 1957, the whole-body dose for the general
population was lowered to .5 rem per year by the NCRP. This was
published as an insert into the Bureau's Handbook 59. The AEC also
published this and other recommendations in Appendix 10, p. 400 of its
22nd Semiannual Report to the Congress.
(c)
In 1960, the Federal Radiation Council defined two guides for
the general population.
(Federal Register, May 22, 1965, pp. 6953-55)
The “radiation protection guide" for the general population under
normal circumstances was .170 rem per year.
The “protective action guide (category 3)" was defined to cover the
long-term harm by cesium-137 and strontium-90 acting through the food web
after the first year of a contaminating event. The FRC recognized the
great diversity of such situations.
It concluded that protective action
must be determined on a case-by-case basis when the annual dose to the
bone marrow after the first year would exceed 0.5 rem to individuals or
0.2 rem to a suitable sample of the population.
{Such an evaluation involves cost-benefit analysis. Suppose that
the excess bone-marrow dose over a l0-year period is estimated to be 15%.
Would this be sufficient to warrant a population giving up the use of its
homes and land? Obviously, the excess dose would be trivial from the
point of view of harm, whereas the personal loss measured in terms of
social values would be considerable. To emphasize the need for judgement
of this kind, the Federal Radiation Council instituted the tern
protective action guide rather than standard.)
(d) In 1979, ICRP Publication 30 subsequently nodified for the
transuranics in Publication 48, 1986, provided annual limits for the
intake of radionuclides by workers. Divided by 30, they are equal to a
committed effective dose equivalent per year of .170 ren.
((e)
Dr. Alan Richardson of EPA (Guides & Criteria Branch) has
informed me (2/8/89) that representatives of EPA, the Food & Drug
Administration and the Department of Agriculture have begun to discuss
possible revisions in the general population guides, and that a paper for
public discussion should be ready sometime next winter.]
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