Radon exhalation and emanation assessments in the Transdanubian Central Mountain in Hungary

Objective

To determine the radium-226 activity concentration, the massic radon exhalation rate and emanation factor of 55 soil samples from the Central Transdanubian Mountains in Hungary as well as possible radon exhalation hotspots in the sampling area were determined. Further indoor measurements are planned to investigate the possible exposure to radon of the inhabitants.

Methods

The radium-226 activity concentration measurements were carried out with a semiconductor HPGe gamma-ray spectrometer. The massic radon exhalation rate and emanation factor were determined by measuring the radon activity concentrations using the accumulation method with a system developed by our department based on an AlphaGUARD DF2000 portable radon monitor.

Results

The activity concentrations of radium-226 were between (11.4 ​± ​2.5) and (118.2 ​± ​3.0) Bq/kg, while their average was 39.51 Bq/kg. The massic radon exhalation rates were between (1.02 ​± ​3.64) mBq⋅kg^−1⋅h⁻¹ and (275.63 ​± ​4.05) mBq⋅kg⁻¹⋅h⁻¹, while their average was 39.51 mBq⋅kg⁻¹⋅h⁻¹. Finally, the emanation factors were between (0.01 ​± ​0.04) and (0.80 ​± ​0.03) with an average of 0.30.

Conclusions

In our study, the results recorded from the bedrock at the sampling sites were analyzed. 9 samples were taken from sites comprised of limestone bedrock, moreover, the average radium-226 activity concentrations and massic radon exhalation rates at these sampling sites were higher than average. It was also concluded that although no regional correlation can be seen from the results, a possible smaller radon hotspot was identified from our measurements where further sampling will be carried out.