Re: SB: SB- fly ash articles

[Sherwood Botsford <sbotsford@sjsa.ab.ca>]

On Thursday 29 August 2002 02:15 pm, W wrote:
: In addition for the potential for naturally occuring uranium
: ending up in your walls, slab floor,etc (via fly-ash), I
: understand that "low-level" radioactive waste is often
: disposed of in concrete blocks used for construction.  People
: who have found radioactivity seeping into their homes from the
: basement/crawlspace often have concrete block foundations.
:  Makes me wonder about the relationship between cheap concrete
: block housing projects and environmental racism/classism...
: ---


Let's get some perspective on this:
Uranium occours in dirt at a typical level of 9 ppm.  That's 9 
grams per metric ton, or about 15 grams per cubic yard.  Often 
there is a similar amount of thorium..

There is a fair amount of variation in this from place to place. 
 
Depending on the qualify of the coal, this will be concentrated 
by a factor of 4 to 20.  

The chief concern in basements is radon, which is part of the 
decay process of radioacative heavy metals.  Radon, ulike the 
others, is a gas, and hence can move around.

Thus having a basement dug into an open pore substace (gravel, 
sand) allows you access to all the radon produced for many feet 
around your basement, while having a basement with no air 
exchange with the subsoil has very little.

Concrete block is intrisically more porous than poured concrete. 
Adding a good vapour barier and setting up reasonable air 
exchange should be all that is required.

Remember too, when getting all excited about radiation:
1.  There is always a degree of natural radiation.
2.  Radioactive substances gradually lose there toxicity.
3.  Chemical toxins, unless there is a chemical breakdown 
process stay toxic forever.

Even highly radioactive substances, such as spent fuel rods 
within a few years (5? 15?) cool off to the point that they are 
about as radioactive as the original ore.  (This doesn't make 
them as safe as the original ore, since ores tend to be water 
insoluble, while decay products have the potential of moving
with the water.
-- 
Sherwood Botsford				1-780-848-2881 Ext 134
St. John's School of Alberta			RR - 5 Stony Plain, Alberta TZ7 
1X5
Alternate address sgbotsford@yahoo . com

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