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.	2010 HPS Midyear Topical Meeting Radiation Risk Communication to the Public 24-27 January 2010 Albuquerque, NM
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07 November 2009

Answer to Question #5868 Submitted to "Ask the Experts"

Category: Environmental and Background Radiation — Building and Construction Material

The following question was answered by an expert in the appropriate field:

I received a call from an agitated individual who wanted to know why concrete is chosen as a radiation shielding material when it is known to contain naturally occurring radioactive material. My response at the time was that (a) concrete is a very practical and cost-effective material to use, (b) its natural radionuclides are at low concentrations, and (c) internal radiation self-absorption processes are at work. Unfortunately this caller was not satisfied with this answer, so I turn to Ask the Experts for a more thorough, authoritative response.

I really don't know how you can give a much better answer except to point out that everything—even the agitated caller—contains some radioactivity and that it is impossible to achieve a zero radiation dose. As you pointed out, the radioactivity in concrete is present in trace amounts and does not pose a hazard and can only be measured with very sensitive analytical techniques. But concrete is a good absorber for penetrating external radiations such as gamma and x rays, and thus can be used to reduce the unwanted radiation doses emanating from x-ray machines used in medicine and industry, as well as gamma-ray sources which have many beneficial uses, including radiotherapy.

Ron Kathren, CHP

Answer posted on 16 November 2006. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.