Seae
-
37
#
reported by Park, et al, the beagle dog with the smallest
lung burden,
i.e., 0.2 uCi, developed
lung cancer.°"
The
highest burden in Table V is comparable to the lowest
beagle exposure; the lowest exposure in Table V, the 19
cases with lung burdens in the 0.024 uCi range are only an
order of magnitude less than the lowest beagle exposure.
We would suggest that this is potentially a serious situation.
_ As of this time, none of these individuals has developed
"
lung eancer.°”
However, it is only9 years since the exposure
and there is good reason to suggest that the latent period
(the time between exposure and the development of cancer)
is much longer than this.
In the beagle dog experiments,
the lowest lung burden was associatea with a latent period
of li years.
The latent period may be longer in man and
particularly at these lower dosages and the small number of
cases involved.
Therefore, while these exposed individuals
will be expected to supply pertinent data relative to this
hot particle cancer risk over the next 10 to 20 years,
these exposures give us no information at this time that would
Warrant modifying the risk per particle or the critical
particle activity.
64/
Park, J.F., et al, Wealth Physics, On.
65/
Richmond, Chet, Op.
cit., p.
320.
cit.
p.
805.