Radon-222 measurements in Tanta ground water supplies

The 222Rn concentrations in about one hundred samples of ground water collected from 44 wells through 12 drinking water sources of Tanta city were measured. The water samples collected carefully in four liters Marinelli beaker were immediately transported to the laboratory and measured with a low-background gamma-ray spectrometer employing a 50% HPGe detector. The radon concentration was derived from the gamma-ray measurement of its short-lived daughters 214Pb and 214Bi. The measurement was started about 4 hours later than the sampling time to attain a radioactive equilibrium between the 222Rn and its daughters. The samples were then measured for several days in order to check that both radionuclides decay with the half-life of 222Rn. All ground water samples have low radon levels with a weighted average concentration of 0.35(5) Bq/L. The222Rn concentrations ranged from 0.13 to 0.63 Bq/L. The results are discussed and compared with the reported ones