[ RadSafe ] Radioactivity in Granite Countertops

[John R Johnson]

Stewart

I assume "NO" means "not any", and not nitrous oxide!

John

On Mon, Feb 27, 2012 at 10:39 AM, Stewart Farber <SAFarber at optonline.net>wrote:

> Does anyone know if there some types of granite that contain NO enhanced
> levels of natural radioactivity? This has never been my experience, but I'm
> no geologist.
>
>
>
> I've done studies with high-pressure ionization chambers in many places
> showing clearly elevated levels of radioactivity contained in granite in
> construction throughout the Northeastern US as indicated by elevated gamma
> dose rates of 20 micro-R/hr [200 nSv/hr] or more  [ in close proximity to
> granite walls -approx. 1 foot distant] vs. typical background dose rates
>  of
> about 8 micro-R/hr [ 80 nSv/hr] for the area.
>
>
>
> Every HPIC measurement near granite I've made around Boston [ at the
> Christian Science Church, South Station, Bunker Hill Monument, steps of the
> MA Statehouse, granite Colonial era wharf buildings]  or all around
> Westerly, RI [a town where almost every building is made of granite], or in
> NH or Maine, or  the Harrisburg, PA Capitol granite steps,  has shown about
> a doubling of background dose rate measured with a HPIC a  foot  or so from
> the granite used in construction.
>
>
>
> Another interesting measurement was of a doubling of background dose rate
> near a large piece of Aswan red granite from Egypt which was used to make a
> sarcophagus for a princess many thousands of  years ago. This ancient
> granite ceremonial Egyptian coffin is currently displayed in front of the
> Boston, MA Museum of Science.
>
>
>
> All  granite mentioned  above would show greatly elevated count rates when
> measured on contact with a standard pancake GM like an Ludlum 44-9 or
> HP-360.
>
>
>
> However, a friend has recently installed granite countertops which shows
> background rad levels on contact. So has my friend purchased "real" granite
> with all the  natural radioactivity it "should" contain or has she been
> cheated of her little bit of residual elevated U-238, Th-232, and K-40
> radioactivity from the Big Bang?
>
>
>
> Thoughts?
>
>
>
>
>
> Stewart Farber
>
>
>
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