Abstract
Radon, a naturally occurring radioactive noble gas, is the main source of the natural radiation received by population. It is derived from the activities of naturally occurring radio-nuclides of uranium- and thorium series, specifically of radium in rocks and can diffuse directly or as solution in water to the earth's surface. Measurements of Rn-222 concentrations in 21 water samples collected from groundwater wells in Buraydah city, Saudi Arabia (SA) were investigated. Most of the raw-water radon was removed by plant treatment processes. Aeration and filtration resulted in 60% radon removal compared to about 79 similar to 97 % removal in treatment plants by reverse osmosis-or electro-dialysis processes along with aeration. The concentrations of Rn-222 were measured by gamma-ray spectrometry using HPGe detector with relative efficiency of 50%. The radon activity concentration was determined by taking the average concentrations derived from gamma-ray lines associated with Pb-214 and Bi-214 decay. It was found that the concentrations of Rn-222 ranged between 1.79 +/- 0.5 to 9.28 +/- 1.17 Bq l(-1). These values are below 11.1 Bq l(-1), recommended as maximum level according to the proposed national limits.