Answer to Question #11848 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation — Radiation effects to embryo/fetus

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


I recently visited a health spa in Pavel Banya, Bulgaria, and spent about 1.5 hours (h) in an indoor swimming pool containing hot spring water. Only afterwards did I find out that the water was hailed as "healing water" because it contains a mixture of substances, including radioactive radon at a concentration of 843.6 becquerels per liter (Bq L-1). I am extremely concerned, as I am three to four weeks pregnant. I am very worried that my inhalation of radon-contaminated air and my presence in this environment has caused damage to the fetus, leading to birth defects or miscarriage. My husband and three-year-old child also spent a total of 2.5–3 h in this swimming pool. We did not drink any of the hot spring water. Could you please provide some assessment of this scenario?


I can appreciate your concern in discovering that you and your unborn child were exposed unwittingly to radiation in the form of radon gas. However, based on the information you provided, I can assure you that the additional radiation exposure that you received at the health spa should not result in any health risks to you, your unborn child, or your family members. Let me explain.

First, all of us inhale radon gas and its radioactive daughters all the time, no matter where we are on the planet. So your exposure at the spa was not different from your normal exposure to radon in terms of the type of radiation you were exposed to. The only difference was in the rate of exposure, which at the spa was certainly higher than normal. The good news is that you were only exposed for 1.5 h, your family about twice as long.

I calculated that the amount of radiation dose that you and your unborn child received at the spa amounted to an increase in radiation dose from radon during the year of less than 1% of what we all normally receive from natural background. This increase is too small to result in any increase in risk, even though it was all received during a brief period of time. Therefore, please be assured that you did not expose yourself or your baby to levels of radiation that you should worry about.

Raymond A. Guilmette, PhD

Answer posted on 1 February 2017. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, 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. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.