AW: [ RadSafe ] Re: Residential radon risk

[Philippe Duport]

Dear Dr. Cohen,

Why do mines depend solely on WL?  This is a typical case of searching under 
the lamp post!  Measuring Rn gas concentration or WL is much easier than 
measuring something (what, how?) truly representative of lung dose, IF lung 
dose is itself a measure of lung cancer risk at very low dose rates of alpha 
radiation.  I wish some day a group is assembled to put all the cards on the 
table and to look, without prejudice and a priories, at the logical 
implications of ALL the assumptions used so far in the estimation of Rn risk 
at today's indoor and workplace Rn concentration.

Philippe Duport



----- Original Message ----- 
From: "Bernard Cohen" <blc+ at pitt.edu>
To: "Philippe Duport" <pduport at uottawa.ca>
Cc: "Bernard Cohen" <blc at pitt.edu>; <GELSG at aol.com>; <radsafe at radlab.nl>
Sent: Thursday, June 02, 2005 9:57 AM
Subject: Re: AW: [ RadSafe ] Re: Residential radon risk


> Dear Philippe:
> Many thanks for this info. If the variation of unattached fraction is so 
> large, why do mines depend solely on WL? In any case, the variation in 
> homes can be very much larger because of systems for dust removal in 
> common use.
>
> Philippe Duport wrote:
>
>> Dear Dr. Cohen,
>>
>> More recent data on the unattached fraction in U mines:
>> Keng Wu-Tu, Isabel M. Fisenne and Adam R. Hutter.  SHORT - AND LONG-LIVED 
>> RADIONUCLIDE PARTICLE SIZE
>> MEASUREMENTS IN A URANIUM MINE.  DOE-EML Report EML-588, April 1997
>>
>>
>>
>>
>>
>> Unattached fraction : 0.3 % to 23.9 % in a Canadian uranium mines in 1995
>>
>>
>>
>> Wu-Tu et al data confirm, independently, those obtained in French U mines 
>> some 30 years ago.
>>
>> Dr. Cohen, you may have a point, the unattached fraction may be quite 
>> variable and the raw WL value may not be the right parameter to 
>> characterize the risk of lung cancer due to radon decay products, and 
>> upon which to base lung dose calculations.
>>
>>
>>
>> Wu-Tu et al found also a sizable amount of ultrafine long-lived aerosols 
>> (elements of the U 238-235 decay series other than short-lived Rn decay 
>> products) between 10 and 100 nm (mode at 30 nm).  These were never taken 
>> into account in lung dosimetry.
>>
>>
>>
>> P Duport
>>
>>
>> ----- Original Message ----- From: "Bernard Cohen" <blc+ at pitt.edu>
>> To: "Philippe Duport" <pduport at uottawa.ca>
>> Cc: <GELSG at aol.com>; <radsafe at radlab.nl>; "Bernard L Cohen" 
>> <blc at pitt.edu>
>> Sent: Wednesday, June 01, 2005 11:55 AM
>> Subject: Re: AW: [ RadSafe ] Re: Residential radon risk
>>
>>
>>>
>>>
>>> Philippe Duport wrote:
>>>
>>>> Please see "Determination de la fraction libre d'activité existant sous 
>>>> forme de RaA non attaché dans l'atmosphère d'une mine d'uranium" by A. 
>>>> Chapuis, A. Lopez, J. Fontan, Health Physics Vol. 25, pp. 59-65 (1973). 
>>>> At that time, Health Physics accepted papers in French!  The fact that 
>>>> some papers were published in French or in languages other than English 
>>>> does not imply that the research has not been done and the information 
>>>> does not exist.
>>>>
>>>> Chapuis et al report unattached fraction values from 1 or 2% close to 
>>>> an active stope, up to 15 to 20% without, or far enough from, active 
>>>> mining operations.  Miners do not spend all their time in close 
>>>> proximity to active mining operations.
>>>>
>>>> I measured  unattached fraction values of the order of 30% in an 
>>>> isolated, inactive part of an underground uranium mine with forced 
>>>> ventilation (P. Duport, G. Madelaine, A. Renoux. Mesure de la fraction 
>>>> libre dans l'air d'une mine d'uranium laboratoire, Chemosphere 
>>>> 4(5):283-288, 1975) - sorry, another paper in French.
>>>>
>>>> The unattached fraction is of course very sensitive to aerosol 
>>>> concentration, but it is a serious mistake to assume that it is always 
>>>> negligible in mines.
>>>>
>>>> Philippe Duport
>>>
>>>
>>>       ----My apologies for aaying unattached fractions were close to 
>>> zero in mines. The point is that they are presumably small enough and 
>>> have little enough variability that they do not affect the radiation 
>>> dose. If they did, it would not make sense to use WL as an index of 
>>> radiation in mines
>>>
>>