fron these observations about the mochanism of contamination,
and then Dz. Dunning is soing to cupoly soe of the context her
the Antorprotntion both in terms of the natural backsrotnd
radiation levels
which ere found and aiso tho levols of radia-
tion which are generally considored to have wowe biolosic ad
hazard implication.
Thora aro rany vericties of radiation hagard including the
sternal radiation both beta and ganna, and tho pessibilitses
going +o select two or threo Walch we consider the most
important
and I will spend my time on those
5{ate
Obrservations have boon mace by ours New York Overations
Office on the amounts of radioactive fallout in tho castern part
of the United States and elsewhere fron vadeh it is possible to
dctermine roughnly the external gamma and beta radiation which
are found in envircnments as a fuaction of time during the last
few years.
The dose levels have, of course,
fluctuated with the
weapons test, and i am not going to try to go into ecotail on
that.
They have put out oan crticie in Science
a few weoks aso,
and you can get more catails thore.
Generally speaking,
to nail down a fow nunbers,
calculate that the order of
one can
magnitude of the bsia radiation dose