An overall genetic risk assessment for radiological protection purposes.

Risks of serious hereditary damage in the first and second generations after low level radiation exposure and at equilibrium were calculated by using a doubling dose of 100 rem (based on experimental work with the mouse) and by considering separately the various categories of genic and chromosomal defect. Prenatal lethality has not been included. It is estimated that after the exposure of a population of future parents to a collective dose of 1 million man-rem, about 125 extra cases of serious genetic ill health would appear in children and grandchildren. In all future generations, a total of about 320 cases is expected, provided the population remains of constant size. It is emphasised, however, that a number of major assumptions have to be made in order to arrive at any overall genetic risk estimate, so that the confidence limits of these figures are bound to be wide.