Granite Counters: Uranium Ore In Disguise?
Cathy Woods’ new granite counters were radioactive. They contained as much uranium as commercial uranium ore. The showroom that sold Cathy her Jupurana Bordeaux granite did not warn her that some granite is radioactive.
When I contacted the salesman, posing as a customer, he assured me their granite “is no more radioactive than soil or water”. However, Cathy’s granite emitted gamma radiation at many times background. The radon gas emitted by the stone tripled the radon concentration in her kitchen.
Jupurana Bordeaux is one of the granites that are likely to be radioactive. Just weeks after having her counters installed, Cathy learned of the possibility and enlisted the assistance of professionals to assess her exposure to radiation and radon gas.
Radon is a daughter product of uranium, so granites containing uranium will emit radon. According to the EPA, radon is the leading cause of lung cancer in non-smokers. Cathy and her husband both have family histories of cancer, so they were very concerned about elevated radiation and radon in their kitchen.
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Some granite quarries are near uranium mines. Most granite does not contain large amounts of uranium, but some granite can have more uranium than a homeowner would want in the home. Cathy and I measured radiation from about 1,000 slabs of granite in showrooms around the San Francisco Bay Area. Most of the granite was only slightly radioactive. However, a small percentage emitted gamma radiation (penetrating radiation) at many times background.
We found Jupurana Bordeaux emitting gamma radiation at nearly 100 times background in the very showroom that claimed none of their stone was radioactive. When Cathy confronted the owner about his granite, he said he had no intention of warning buyers.
Cathy fell in love with Volga Blue granite to replace her Jupurana Bordeaux. It is mostly black with shiny crystals and iridescent “blue eyes”. Gamma emission was barely above background, one of the least radioactive granites we had seen.
We were left with many questions about radioactive granite we saw in showrooms. How much radioactive granite is installed in homes? How many of those homes have young children or pregnant women? Why don’t granite showrooms warn their customers?
Oh, I had better exlain to Terri/Alex about the (sic) addition to your quote. I wasn’t commenting about mental or health issues, I was marking the spelling in the comment as being exactly as you wrote it.
Exlain?? Explain… how funny.
[...] Granite Counters: Uranium Ore In Disguise? [...]
HI Again,
I haven’t had time to check back lately.
So I understand correctly the amount of radiation emitted is what is of concern.
“The EPA “action level” for radon is 4 pCi/L.” This is airborne levels when measured however it is measured, right?
“Some granites emit several hundred pCi/hr of radon from each square foot” What does this translate into an airborne level.
In my reading I have found that water levels translates to 10000pCi/L in water to 1pCi/L in air.
http://www.bae.ncsu.edu/programs/extension/publicat/wqwm/he396.html
Is there an effective way to determine the effect “xxx pCi/L” in each square foot of granite will have in my home?
Or even better since we cant determine variables like ventilation, Is it possible to determine how much granite it would take in a sealed room of xxx sqft emitting xxx pCi/L to make it surpass the standard of 4pCi/L airborne.
Thanks in advance!
Tim
Tim,
those are good questions.
4 pCi/L is the airborne level that the EPA recomends action at. However, the EPA bases their 21,000 radon deaths per year in the U.S. at only 1.3 pCi/L, so that tells you that there is no safe level of radon. Congress stated that the long term goal is to reduce radon to outdoor air levels, .40 pCi/L.
An effective way to test your granite would require setting a meter under an accumulator (we use aquarium tanks) on every square foot of your granite, but the bottom of the granite usually puts out more than the polished top. I ran a test yesterday, got almost 10 times more radon from the bottom accumulator than the top accumulator. It would be easiest to close off the room the kitchen is in, then do a CO2 test alongside a radon test for 48 hours to get the amount of radon coming off the stone.
We have a radon room running, 36 square feet of low radiation (26 uR/hr average radiation per 3″ square grid, just 1 uR/hr over our maximum allowed radiation level for fabrication) can put the room over 30 pCi/L in just a day if the weather is calm. We then used forced ventilation, 90 liters per minute (.22 ACH meaning the air was changed out completely every 4 to 5 hours) and the radon fluctuates between 2 and 4 pCi/L during a 48 hour test. That .22 ACH is about average for a newer home, not a super tight energy efficient home though and not an older, leaky home.
XXX pci/L of radon risk? The EPA used to say that 8 pCi/L is like smoking a pack a day. Turns out it is a bit more complicated, but that is a way of explaining things that is both simple and effective.
Great article. Thank You!
As a prospector who has spent a day running up and down a mountain range looking for rock outcrops besides granite hoping to find gold, I can tell you that if there is uranium to be found, it is found in Granite. In all the rock outcrops I found in the area I was at, all the outcrops were granite, and all carried uranium ore, to the extent of having been commercially mined in the past.
So it should be no surprise to get radioactive counter tops when having granite brought in… If you want a chance for gold or silver instead, go for slate…
Sounds like stainless steel countertops should be alot more popular. S/S is a true green and recyclable product (and there are no health issues).
Joe