Yes, some granites and quartzes contain uranium, a radioactive element. You are safe from significant exposure to the uranium while it is locked in the granite and/or if it is present at very low levels within the installed materials.
Your main exposure risk comes not from the uranium but from its radioactive decay product, radon, a noble gas that also radioactively decays, emitting alpha, beta and gamma radioactivity. Radon emission varies from place to place, and from material to material, but is commonly found in hot springs, caves, mines, petroleum products, natural gas, slate and granite stone, and throughout the atmosphere.
Radon decays to other less radioactive compounds, with a half-life of 3.8 days, and because its evolution is dependent on the mass of the emitting materials, the less of it you have and the more a space is ventilated, the less exposure you have to the radiation.
- The most serious exposures happen in unventilated areas like uranium mines, and basements, where radon, being heavier than air, will tend to accumulate in an area.
- Where the stone for your granite or quartz countertop was quarried from will determine the amount of uranium and radon and your relative potential exposure levels. Obviously, nobody can tell you this except the manufacturer or mining company for your specific stone. As a prerequisite to purchase, ask them to provide testing data showing the radiation levels from the stone.
- There are tests you can buy -- or depending on where you live, can sometimes get free -- that will tell you the radon exposure levels in your house, or even in an open field. They are cheap and take 2-7 days.
I think we should all be concerned about cancer, but the real problem is what exposure to potentially carcinogenic or mutagenic agents is deemed an acceptable amount. The human organism and most other biological organisms are amazing machines, that through millions of years of evolution have developed redundant fail-safe mechanisms to stop diseases like cancer from killing us.
Cancer, actually a family of diseases characterized by the uncontrolled growth of cells, is the result of a multiple genetic mutations to several of the fail-safe mechanisms. Genetic mutations happen in essentially three ways.
- They are passed down from your parents,
- They are the result of errors in your cellular pathways responsible for cell division and DNA replication, or
- The DNA is mutated at some point in your life, through exposure to chemicals or radiation that directly or indirectly cause mutations.
You cannot control the first two, but you can control the last one. This is your only opportunity to at least partially control your destiny, by changing how or where you live.
The problem is that we live in polluted cities, drinking polluted water, breathing polluted air and eating polluted, chemically fertilized, pesticide-laden foods. Our technologies are now able to build things out of materials that our bodies are not meant to be exposed to, like plastics, paint thinner, VOCs, cigarette smoke, and a multitude of other chemical entities. The result is that we are getting cancer at faster and faster rates because we are being exposed to DNA-mutating agents at greater and greater rates and concentrations.
But what has to give to be exposed to no mutagens at all? Daylight, more specifically ultraviolet light, is a potent carcinogen, so we wear sunscreen, but did you ever notice that not everybody buys the highest rating SPF that they can get? If we really didn't want any chance of getting skin cancer, we would never go outside with exposed skin. Yet we do. How many people do you know who smoke? How many people do you know who drink alcohol, which increases the risk of over half a dozen different types of cancer? What are we willing to cut out to decrease our risk of getting cancer?
So now back to your question. When you get the radiation information back from a manufacturer, only you can decide what is an acceptable amount of radiation to expose yourself or your family to. Is it none at all, or is it more than absolutely nothing because you know that your house is big and you keep it well ventilated, so the exposure potential will always be very low?
Now, have you tested your crawlspace, basement, or house for radon emitted from the ground in your area? There is a lot more earth under your house than quartz in your kitchen.
For more information:
You should also read Bill Bradbury's Ask A Pro Q&A, "Where can I find radon testing equipment for granite countertops? And what are safe levels?"