There really isn’t any need to check for Radon on granite counter tops. Even the EPA came out with a position paper (about 2 years ago I think) on it saying it is not necessary. I can’t find the doc but I read it once.
Even if they weren’t the only radon that could escape would be that coming from radium that is on the surface. Anything inside would be trapped there.
As was mentioned earlier there is an epa paper done in conjunction with the National Radon Proficiency Program (NRPP)… (or maybe it was AARST I don’t recall) that stated that the primary concern is the air.
You should test the air, and if elevated, then mitigate soil gasses and re-test.
Any radon inside the granite that was released from decay from radium would undoubtably escape in short order. The question becomes one of degree- if there is in fact enough granite within the structure to appreciably elevate the level within the structure then possibly it could be a concern. But then wouldn’t a standard testing protocol indicate that as a problem? Why test the granite only? The only time I could see this as useful would be when other sources of elevated levels were eliminated and there was a whole load of natural stone in the house.
I don’t think they’re sealed to the particles and radiation emitted by the radioactive uranium, etc. I’m not concerned with radon off gassing and the very small contribution to overall radon levels in a house but with the alpha & beta particles plus gamma radiation that are emitted just at genital level when you’re standing at the counter. If there happens to be a hot spot along the edge…what’s happening?
No one seems to have considered this…but when mentioned to a doctor whose house I was at last year…he screwed up his brow and said “Hmm, never considered that!!”
Some interesting high emissions measurements mentioned in this 2 year old article.
Note that EPA and AARST, in their position statements, only talk about radon in the air and not about the particle and gamma emanating from the counters…
“It’s pretty easy to understand why tile, granite, and kitty litter are radioactive. They contain low levels of minerals that naturally decay. Bananas are radioactive for a similar reason. The fruit contains high levels of potassium. Radioactive K-40 has an isotopic abundance of 0.01% and a half-life of 1.25 billion years. The average banana contains around 450 mg of potassium and will experience about 14 decays each second. It’s no big deal. You already have potassium in your body, 0.01% as K-40. You are fine. Your body can handle low levels of radioactivity. The element is essential for proper nutrition. If you have a banana in your car for your lunch you aren’t going to set off a Geiger counter. If you carry a produce truck full of them, you might encounter some problems. Ditto for a truck of potatoes or potassium fertilizer.”
Q1: A: Don’t know, probably
Q2: A: Don’t know, not a chemist, but probably.
Q3: A: I got the information by passing a Geiger counter over a banana. (Actually I didn’t do it, but I watched it being done.)
Have you ever passed a geiger counter over a hot spot in a granite countertop?
If not, we then have no comparison with the little bit of natural background radioactivity in a banana and our bodies. Like I said, I’m not concerned about the radon in air contributions from granite but potential hot spots along a counters edge.
[FONT=Verdana][size=1][size=2] "Granite countertops are the latest trend for bathrooms and kitchens, but Rice University’s professor William Llope has discovered some radioactive countertops made out of granite. Llope says radiation is all around us. It is in the soil and even in every day household items like smoke detectors and granite countertops. Most of them give off harmless amounts of radiation. Llope calls it a part of the “natural background.” However, he has found high levels of radiation in some of the granite samples he has collected. Llope says the radiation doses are hundreds if not thousands of times the natural background. He says exposure to these levels of radiation over time can potentially cause cancer."
Radiation is measured in units called millirems (mrems), with the average annual dose per person estimated at 360 mrems or 0.04 mrem per hour. According to tests performed on natural stone countertops by W.J. Llope, associate professor of physics at Rice University’s Bonner Nuclear Laboratory, most natural stone countertops emitted radiation “at 0.1 to 0.3 mrem per hour,” and were “not a significant risk.” However, “a handful of samples” emitted 3 to 4 mrem per hour, a rate “the EPA would consider dangerous assuming long-term exposure and would recommend remediation.”
I would not attempt to disagree with professor Lope in his assertion that exposure to those levels over time can potentially cause cancer. I believe him. But I don’t believe that is the entire story either.
I take what I believe to be a very practical approach to this. A) Most granite is harmless (as stated by your professor). B) No one sleeps on a granite countertop. So your chances of having a “bad” one is small, and even if you do have one, you would have to have prolonged exposure to it to have an affect.
All in all, based on the studies I’ve read, along with my own deduction, I think this hubub is much ado about nothing.
BTW, I don’t pay any attention to the “hype” on either side of the issue. The granite countertop manufactures claim there is nothing to it (obviously biased). On the other side of the issue, most of the articles I’ve seen claiming the sky is falling, ultimately come from two sources…composite counter top manufacturers, and radon/radiation testing companies. So both sides are biased. I’ve based my conclusions on some independent university studies that I have read. (and no, since you are about to ask, I don’t remember where they were, or what the exact details of them were to quote for you. Sorry.)