Re: LNT

[William V Lipton <liptonw@DTEENERGY.COM>]

If I remember correctly, the only radiation protection standard based on

human data was for radium and other bone seekers.  A cohort of dial

painters was followed, and it was found that no individual with a body

burden of less than 1 uCi  suffered any ill effects from the uptake. 

Throw in a safety factor of 10, and the ICRP 2 standard was 0.1 uCi. 

This was then expanded to other bone seekers, based on energy, QF, and

distribution factors.  This was a sensible standard that held until

ICRP 30 and the new 10 CFR20.  Where did we go wrong?

The opinions expressed are strictly mine.
It's not about dose, it's about trust.

Bill Lipton
liptonw@dteenergy.com

RuthWeiner@AOL.COM wrote:

At least for now I would go with the HPS statement that at less than 1 rem/year (I am not sure of this number)  the cancer risk should be treated as a distribution whose lower end is zero (those are not the exact words -- I am paraphrasing from memory).

What strikes me as ridiculous is multplying a population dose of, say, 15 mrem/year (the EPA air standard) by 0.0005 and saying that an individual exposed to this has one chance in 100,000 (it's actually 7.5E-6) of a "latent cancer fatality" from that exposure.  Even worse, that in an urban population of a million persons with an average exposure of 15 mrem, there will be 7.5 "latent cancer fatalities"  attributable to that exposure.  It's the blind application of a linear extrapolation to zero that is simplistic and I think misleading.

The literature, including Health Physics, increasingly shows evidence of thresholds (and I am not talking about Bernie Cohen's papers).  One recent article on the atom bomb survivors seemed to show a threshold for cancer of 20 Gy!  I am not touting this -- I think we need to keep studying this and come up with the same kind of completely credible threshold that EPA has set for, for example, the common air pollutants.

Ruth Weiner, Ph. D.
ruthweiner@aol.com