[Radon 222 in drinking water from Jelenia Gora area].

In the last decade one can observe an increasing interest in the study of 222Rn levels in water samples. In Poland, radon concentration is measured continuously and routinely only in mineral and medical waters from springs located in the area of health resorts in the Sudety Mountains. The reason for these studies is the fact that waters present in this area have a high radon concentration. Radon--222 concentration in surface water, wells water and tap water in Jelenia Góra has been quantitative determined. The measurements were performed using the alpha liquid scintillation counting method. "Grabarów", the main waterworks in Jelenia Góra is supplied with the mixed water consisting from the surface water (river Bóbr), which main characteristic is low radon concentration (below 11 Bq/l), and from ground water with the radon concentration from 179.6 Bq/l to 289.0 Bq/l in it. Also, waterworks "Ceglana", "Pod Karpaczem", "Sniezne Kotły" is supplied with the ground water have a high radon concentration: from 93.2 Bq/l to 216.4 Bq/l. The next waterworks: "Podgórzyn", "Leśniczówka", "Kamienna Wieza", "Górzyniec" and "Centrum-Jelchem" is supplied with the surface water in which the radon concentration is low: from 1.1 Bq/l to 7.5 Bq/l. The annual effective dose to an individual from an intake of radon-222 via ingestion of drinking water is calculated by the Crawford-Brown's biokinetic model. In the present study it was found to be about 0.9 mSv/y (222Rn concentration level in drinking waters about 200 Bq/l).