Occurrence of radon in the central region groundwater of Saudi Arabia

Radon levels were measured in eight water supply municipalities of the Central Region of Saudi Arabia. Samples were collected from 77 wells and 6 treatment plants supplying drinking water to over 500 000 inhabitants. The well water radon level was in the range of 0.89– 35.44 Bq/l with an overall weighted geometric mean value of 8.80 Bq/l. Most of the raw water radon was removed by the plants’ treatment processes. Aeration and filtration resulted in 60.5% radon removal compared to a removal in the range of 78.7–96.5% in treatment plants containing reverse osmosis or electrodialysis processes along with aeration. The plants’ product water contains radon levels in the range of 0.15–5.71 Bq/l whereas two water systems with no treatment contain levels of 2.07 and 1.19 Bq/l.