Radon measurement from touristic underground waters in maramures county

Three different methods were used to measure radon concentration in groundwater near Baia Mare andin other places of touristic interest from Maramures, the northest district of Romania. The majority ofthe samples have been measured using two methods of alpha detection. The Radon Emanometermethod has a sensibility ofl 0.074 Bq/l (2 pCi/l) and it uses a device of Russian provenience. We madeseventy (70) different measurements with this device. From these 70 measurements, ten were alsomade with the second method, which used a device of Czech provenience, LUK-3A, which has astandard deviation of 10% and a sensibility of 0.56 Bq/l (15 pCi/l). We also measured radonconcentration in five different underground waters by absorbing radon on charcoal and using gammaspectrometry. The methods have been compared and we have used the first two methods to evaluatethe accuracy of the third one (the sensibility was estimated to be about 2.962 Bq/l or 80 pCi/l). Thevariation domain of our measurements goes from 1 Bq/l to 35 Bq/l, their graphic representationindicating a log-normal distribution. The geometric mean of this log-normal distribution, GM=5.785Bq/l, is lower than the same value of the domestic water supplies from Iran (10-20 Bq/l) butcomparable with that for the South -Central Texas Water supplies (5-7 Bq/l). Some of our values arehigher than EPA proposed drinking water standard of 300 pCi/l (11 Bq/l). The measurement of radiumproved that radium concentration in these underground waters is negligible. We have also put underobservation one of the springs in order to point out the temporal fluctuations of radon concentrationboth in summertime and wintertime and we concluded that rainfalls are an important factor whichinfluences the 222Rn content.