Re: linear hypothesis

[scherer@uiuc.edu (David Scherer)]

I think a few points are in order in this discussion.

(1) The linear hypothesis applies to stochastic risks.  Drug overdoses are
presumably nonstochastic.  I believe that a linear, non-threshold model is
used for Pb exposure as the basis of the current drinking water standards,
so it isn't only radiation.

(2)  Public health rules almost never wait for a potential hazard to be
proven before they are controlled.  When drugs or medical devices are
developed, they must be proven to be safe, not the other way around.  The
onus is not on proving radiation risks.

(3)  The linear hypothesis simply says that risks are observed to be linear
at high doses, so they should be presumed to be linear at low doses.  A
simple statement of the state of knowledge and uncertainity.  It seems to me
that the main rub is not this principle, but its societal application, the
ALARA principle.  The debate should be this: How do we apply the ALARA
principle at very low doses?  I think BRC is a sensible approach, somewhere
in the 10s of mrem/y range.

(4)  I don't think we should play with scientific interpretation to achieve
changes in ALARA.  Ultimately this approach is likely to be
counterproductive, especially if the radiation biologists do not sign on.
Credibility is our only stock in trade.  Environmental groups have it while
industry does not.  Let's not make matters worse.

(5)  The public does not always demand absolute safety, especially when they
perceive some benefit from the risk.  In the lower 50, we no longer have a
national 55 mph (88 km/h) speed limit, even though the death rate is
expected to rise.  It is our job to show the public and their leaders how
they benefit from radiation sources, and what the efffects of excessive
regulation are.

Dave Scherer
scherer@uiuc.edu