Is there really radon in soil?

As we close up our homes more as chilly weather sets in around the northern US, we also lose access to much of the fresh air we’ve been enjoying all summer and fall. And with this change, comes a risk – but one that can be lessened with proper ventilation. That risk is exposure to radon.

Radon is the second leading cause of lung cancer in the U.S. Lung cancer (1, 2) costs us $2 billion per year in health care costs (3). Why is radon hanging around in your home? Is it in the soil?

11-01-16 radon graphic nick

Well, radon isn’t in the soil, but its parent material, uranium, is. And uranium is radioactive. It’s a natural element of the soil found most everywhere. Fortunately, it is generally found in very low concentrations and makes up part of the natural background radiation that we all experience. But there are situations where uranium is found at much higher levels, particularly around phosphate deposits.

This naturally-occurring uranium decays and turns into other elements. As shown in Figure 1, over millennia, uranium continually becomes radium, which is also radioactive. The radium decays and becomes radon – which is only stable for a few days. But, since the process is continuous, if your home has a high concentration, it usually has a quite steady flow of this toxic substance.

Why is radon exposure worse than exposure to uranium or radium? Because it’s a gas. The other elements associated with uranium decay are solid.

basement foundation plain
Cracks in foundations, around pipes, etc., can be sources of radon leaking into homes. However, newer homes with tight sealing can also be at risk. Radon testing is accurate and inexpensive.

Radon can move as a gas through the soil and enter your house through holes in the foundation. These holes might be found in places like the shower, toilet, other drains, etc. Any dust particles you have floating around your house collect radon – which you can then inhale. And, it’s not just radon you might be inhaling. You could be inhaling all of the elements that radon becomes once it decays – like radioactive lead (see Fig 1). You breathe in the particles which can settle in your lungs leaving a source of radiation within them……not a pleasant story.

If cigarette smoke is also in your home, the risk for lung cancer is compounded. Exposure to both radon and cigarette smoke represents close to 90% of radon-related deaths. With cigarette smoke in the air, radon – and its decayed “siblings” – have many more particles to attach to.

finished basement recreation room
The basement and first floor of homes are at most risk of high radon levels – in areas that have higher radon.

You might think that only older homes are at risk for radon. However, newer homes are sealed very tightly – good for the environment. That leaves less room for radon gas to escape. And, they might also be built on very disturbed soil where uranium has been brought closer to the surface. So, it’s best to have any new home purchase tested for radon. Finished basements are also at higher risk for radon exposure, because they have more contact with the soil around your home. There are treatments that can improve the airflow in your home and lower the exposure to background levels.

Over 30 states have laws or regulations requiring radon disclosure in buying and selling real estate. If you are buying or selling a house and are concerned about radon, you can have most of your questions answered here:

Radon is naturally-occurring. We’re exposed to it daily. Since some homes have higher levels, it’s best to know your risks. Knowledge is power, so give yourself some peace of mind. Have your house tested for radon. The typical cost is less than $50 – money well spent to protect you and your family from this lung cancer risk!

Answered by Nick Comerford, University of Florida

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2 thoughts on “Is there really radon in soil?

  1. hi, I’m a high school student who would like to cite something that you published and I was wondering (if it okay with you) if i could get your name to use on the bibliography -Thanks

  2. Hi Marly, thanks for reading…you can see Nick’s name and institution at the end of the blog post! The organization that sponsors this blog is the Soil Science Society of America, as disclosed under “about us.” Nick is a member, but also a professor at U FL. SF

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