2.4. Radiation dose estimation
In order to assess radiological risk, external exposure to radiation arising from naturally occurring radionuclides can be determined in terms of the absorbed dose rate in air at 1 m above the ground surface. The mean activity concentrations of 238U, 232Th and 40K (in Bq/kg) in soil samples were used, applying the conversion factor given by Beck and UNSCEAR as follows [1] and [24]: