Answer to Question #1880 Submitted to "Ask the Experts"

Q

The building material made from coal ash will give a higher radiation level. Why and how can I measure it?

A

Coal, like everything else, contains naturally occurring radionuclides. In coal, the key radionuclides are members of the uranium series, the thorium series, and ⁴⁰K. When coal is burnt, this radioactive material concentrates in the ash. The resulting concentration is usually high enough for radiation measurements performed on the ash with a simple survey meter to be distinguishable from background. The same is true for the ash produced by burning wood. If you have a radiation survey meter, you might be able to detect an increased count rate when the detector is in direct contact with the building material. If you want to perform a quantitative measurement of the radioactive material in the building material, you must send a sample to a laboratory set up to perform this type of analysis. The most likely type of analysis, gamma spectroscopy, involves counting the number of gamma rays emitted from a known mass of the sample using a sodium iodide, or better yet, germanium detector. The different gamma-emitting nuclides in the sample can be quantified independently because they emit gamma rays of different energies.

Paul Frame, CHP, PhD