Re: LNT, Collective Dose

[Tom Mohaupt <tom.mohaupt@wright.edu>]

A good example of LNT is the number of cancer deaths purported by the EPA.
They say that 7,000 to 30,000 people in the US die from radon each year.
BEIR VI states that if everyone in the US brought their radon levels to
below 4 pCi/L (about 148 Bq/m^3) this number (pick one) would be cut by
1/3. In other words, if smoking does not change and everyone in the US
mitigate their radon levels down to below the EPA action level, there would
not likely be a statistical reduction in lung cancer rates. Most lung
cancers projected by the BEIR committee, and subsequently the EPA, come
from a calculated small risk projected on a huge genuine population exposed
to very low levels of radon. I've heard EPA staff state that if something
is a known carcinogen they have to apply the LNT. What strikes me as
bizarre is that of all the "known" carcinogens for lung cancer, the LNT is
essentially the only one applied to radon. From the studies I've read while
trying to make sense of the radon issue, the LNT is not applied to second
hand smoke, pulmonary fibrosis, diet, or even smoking.

Tom

Ted de Castro wrote:
> 
> Harry Hinks wrote:
> >
> > Mr. DeCastro,
> >
> > I may be mistaken, but I think you are mixing up LNT and collective dose
> > assumptions.
> 
> In a linear risk situation its the same thing!  That is PRECISELY the
> point that many are trying to make here - the summing of person
> microREMs into populational REMs and then declaring cancer deaths!
> 
> >
> > In studies where you collect data at each house, you do not have to make
> > either LNT or the collective dose assumptions.  Assume you go out to the
> > nearest town and randomly choose 3 homes to test their radon in their
> > basement.  Again assume you get readings at the 3 houses of 24
> > pCuries/liter, 2 pCuries/liter and 1 pCuries/liter.  With summary data using
> > the collective dose assumptions, you would assume the basement concentration
> > for each individual in that town is 9 pCuries/liter, correct?  But in
> > reality, you know the basements were 24, 2 and 1.   In studies using data
> > from individual houses, you have the readings.  In summary data studies, you
> > do a poor job of measuring the actual concentrations.
> >
> 
> Well I'll try once again.
> 
> If the risk is LINEAR it is proportional to dose.
> 
> If that risk is R then in house 1  the risk is 24R in 2 its 2R in 3 its
> 1R.
> 
> Risk for that population is then the sum of the individual risks
> 
> = 24R+2R+1R = 27R
> 
> For LNT the average exposure is as you say 9 - thus the average risk is
> 9R thus the total risk for the population of 3 is 27R!!!
> 
> With LNT the prediction is NOT WHO - BUT HOW MANY!
> 
> This is precisely what LINEAR means.
> 
> I think this is what Jim means to by "missing the point".  I'm not
> saying this in a mean way or suggesting any purposeful intent.
> 
> Its is simple math - its is the definition of a linear co-efficient.
> 
> IF this doesn't work - then it is NOT linear!
> 
> I'm not disagreeing with how you suggest the risk should be apportioned
> - I infact do agree - I agree it isn't linear!
> 
> All you arguments are predicated on a supposition that it is NOT linear.
> 
> I don't know your math or statistics background so I cannot comment
> further - but there is nothing magical or mysterious about it.
> 
> THINK about it for a minute.
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-- 
Thomas Mohaupt, M.S., CHP
University Radiation Safety Officer

104 Health Sciences Bldg
Wright State University
Dayton, Ohio 45435
tom.mohaupt@wright.edu
(937) 775-2169
(937) 775-3761 (fax)

"An investment in knowledge gains the best interest." Ben Franklin
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