Results of the radon concentration survey in Sibiu county underground water

In November 2000 a survey of radon (222 Rn) concentration in Sibiu county underground water was conducted. The radon concentration was measured with a A LUK 3A. The radon gas was extracted from water using the LUK VR device that works with LUK 3A. All samples were taken in 0.5 l recipients that were filled and sealed. Samples from eighteen cities and villages were taken. Special care was taken for the samples to be carefully brought to room temperature and not to be agitated or stirred before measuring the radon concentration. In measuring the radon concentration corrections like the solubility coefficient variation with temperature, the radon concentration increase in air in time and the background correction were applied. Results reveal that the underground water radon concentration is bigger in wells located in mountainous area, has an average value in wells from hilly region and is considerable lower in wells located in plain area. Another thing we noticed is that the samples taken from the city water pipe system present lower radon concentration values than the samples taken from home drilled wells. The minimum radon concentration value was found in the drinking water of Sibiu city, 1.6 Bq/l and in Sadu village, 1.965 Bq/l. The highest measured values are 28.1 Bq/l in Rasinari, a village located at the bottom of the mountains and 26.4 Bq/l, in Sibiel, a village 30 km away from the first one. These results reveal that the radon concentration values measured in Sibiu county are comparable with the measured values reported in literature and well below the maximum acceptable values. (authors)