[ RadSafe ] RE: Toxic Countertops

Dan W McCarn hotgreenchile at gmail.com
Thu Jul 24 14:24:11 CDT 2008


It all depends on the permeability of the granite!  Even relatively active
granites usually have very low primary permeability so radon is retained
within the mineral grains and rock itself to a great degree.  That's why
granites are usually in secular equilibrium with all uranium daughters
because they retain radon until it decays.  Most of the activity measured by
a scintillation counter comes from the Bi-214 decay at the end of the chain.
At a larger scale, where granites are fractured and faulted and develop
significant secondary permeability, is there a good likelihood that radon in
significant quantities will be fluxed via changes in barometric pressure to
the surface, and these examples are noteworthy.

But in countertops, chosen to avoid fractures, that is unlikely.  Most of
the radon would be only from the very near surface.  The radon from deeper
inside would have virtually no chance of diffusing to the surface.

My opinion only!

Dan ii

Dan W. McCarn, Geologist; 3118 Pebble Lake Drive; Sugar Land, TX 77479; USA 
HotGreenChile at gmail.com   UConcentrate at gmail.com

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
Of Bob Cherry
Sent: Thursday, July 24, 2008 1:30 PM
To: 'Chris Cherry'
Cc: 'radsafelist'
Subject: [ RadSafe ] RE: Toxic Countertops

Good point about the cemeteries! I will remember this and try to avoid
spending a lot of time in one as long as I can.

-----Original Message-----
From: Chris Cherry [mailto:cpdcherry@] 
Sent: Thursday, July 24, 2008 1:24 PM
To: Bob Cherry
Subject: RE: Toxic Countertops

I'm sure more people are harmed in quarrying the stone and installing it
than get cancer from its radioactivity.  

Someone on the medphys list mentioned that cemeteries are full of both
granite and dead people.  This may not be a coincidence.


--- On Thu, 7/24/08, Bob Cherry wrote:

> From: Bob Cherry 
> Subject: RE: Toxic Countertops
> To: "'Chris Cherry'" 
> Date: Thursday, July 24, 2008, 1:18 PM 
> Old news. We almost got a 
> consulting job on this.
> -----Original Message-----
> From: Chris Cherry 
> Sent: Thursday, July 24, 2008 1:15 PM
> To: Bob Cherry
> Subject: Toxic Countertops
> The article mentions the guy at Rice.
> -CC

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