Geology plays an important role in water and air quality. Naturally occurring radioactive elements such as radium and and uranium are found in small amounts in most rocks. If rocks with greater than normal concentrations of these elements form an aquifer or are present in the soil around a building, the local groundwater or air inside the building may contain unacceptable levels of radioactivity.

One of the most common hazards from the presence of these natural elements in soil or water is radon gas, a byproduct of the radioactive decay of radium. Decay of uranium into radium is part of its natural decay series. The Environmental Protection Agency (EPA) has established the maximum safe levels of this radioactive gas, and simple, inexpensive testing can determine if it is an issue in your home or business.
Here is a general map of the radon potential of soils in the United States:

From “The Citizen’s Guide to Geologic Hazards” published by the American Institute of Professional Geologists (AIPG), Arvada, Colorado

Fortunately, the remediation of this hazard is generally simple and inexpensive. Proper sealing and ventilation of foundations and basements will handle most soil hazards, and filtration and aeration of water will control most water hazards.

The following professional reference materials provide detailed information about this geological hazard and the steps that may be taken to remediate or remove radon gas: