Radon concentration in soil gas and radon exhalation rate in some areas of Ramsar in the north of Iran (high levels of natural radiation areas)

The present paper carried out the measurements of radon activity concentration in soil gas, radon exhalation rate from ground and gamma dose rate. The radon measurements were carried out using the AlphaGuard equipment, and potable survey meter GR-130 was applied for gamma dose rate measurements. The ranges of the obtained results are as follows: 5 - >2000 kBqm-3 for radon concentration (CRn), 0.04 - 2 Bqm-2s-1 for radon exhalation rate (ERn), and 0.08 - 35 μSv h-1 for gamma dose rate. The concentrations of 222Rn in soil gas were found to be higher than the estimated mean worldwide flux of 222Rn of 0.016 Bq m-2s-1 (UNSCEAR 2000). Measurements of exhalation rates of radon from soil show variability that reflects the variability of radon concentrations in near-surface pore spaces. Concentrations of 222Rn in soil gas vary over many orders of magnitude from place to place and show significant time variations at any given site. The study is planned to be continued with measurements being carried out at a number of additional points