Re: linear hypothesis

["ALDEN N TSCHAECHE" <XAT@inel.gov>]

I meant 5 REM not 5 mrem. Remember, the human experience is that the
background dose rate has been decreasing for as long as humans have been
a species. The dose rates millions of years ago were significantly
higher than they are now because, in millions of years, at least some of
the natually occurring radioactive material existing then has decayed to
what we see now. And who knows what changes in the cosmic ray exposure
rate have taken place in the past. By-the-by, is there any way to
measure the cosmic ray dose change as a function of time in the past??
Any one out there have any data?

  So, I think humans can tolerate a significant annual dose, otherwise
we'd all be dead by now. Al.

*** Reply to note of 10/18/95 22:24

From: Ron L. Kathren
To: RADSAFE --INELMAIL RADSAFE

Subject: Re: linear hypothesis
Al --

Did you really mean 5 rem (50 mSv) to be the BRC value?  Isn't 5 mrem
(0.05 mSv) per year more what you had in mind?

Ron
On Tue, 17 Oct 1995, ALDEN N TSCHAECHE wrote:

>
> Thanks for your 5 points. Yes, the linear hypothesis is used for other
> potentially harmful agents, particularly chemicals, by the EPA
> especially. However, ALARA is not. Just wait until EPA mandates ALARA
> for chemicals. One can't "prove" safety if the background is too high.
> Most chemicals don't have a natural background so it is easier to
> "prove" safety than for radiation where the background gets in the way.
>
> Yes, the debate is about ALARA at BRC doses. I'm suggesting 5 rem per
> year is the BRC dose. Use ALARA ABOVE that value, not below. Then study
> prospectively those whose doses exceed the BRC value to see if there are
> any harmful effects.
>
> The linear hypothesis is NOT scientific interpretation to my mind. It is
> only that, an hypothesis, undemonstrated and with some evidence that it
> is not valid. I was always taught that, when just one piece of data did
> not fit a particular hypothesis (or theory), that one piece of data is
> enough to disprove the hypothesis and the hypothesis should be revised
> or discarded. Is not what others were taught?
>
>  The Eagle Alliance was formed to do exactly what you are suggesting,
> tell the public about the benefits of the nuclear industry, among other
> things. Have you read the Declaration of Interdependence? Ask the ANS
> for a copy. By-the-by, does anyone know what the Eagle Alliance is doing
> these days. I haven't seen anything about it since the Summer, 95 ANS
> meeting.
>
> You're right. It is up to us to show the public the benefits of the
> nuclear industry. What would you be willing to do to do that? Al.
>
> *** Reply to note of 10/17/95 11:47
>
> From: David Scherer
> To: RADSAFE --INELMAIL RADSAFE
>
> Subject: Re: linear hypothesis
> 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
>
>