Author(s)

A. A. Al-Zahrany & K. S. Al-Mogabes

Abstract

Measurement of concentrations of naturally occurring radio nuclides together with Cs-137 deposited in soil have been carried out in the Al-Baha region of the Kingdom of Saudi Arabia. Soil samples collected from about fifty locations have been analyzed using high resolution hyper pure germanium spectrometers. Concentrations of the gamma emitting radio nuclides from naturally occurring uranium-radium and thorium series, Potassium-40, and Cesium-137 have been determined for the selected locations. Gamma-ray dose rates have been calculated from the measured concentrations of natural radioactivity in soil. Keywords: natural radioactivity, Cs-137 fallout, NORM, radioactivity level in soil, Saudi Arabia. 1 Introduction Naturally occurring radioactive material (NORM), arising from the decay of uranium-radium and thorium series and potassium-40, has been found in the earth’s crust and soil, the underground water and even in living tissues and organs of any living organism. This presence has been recognized since the early 1930’s. However it received minimal attention until the last few decades, when the role of terrestrial radiation as the main contributor to the collective effective dose of the world’s populations has been recognized UNSCEAR [1–3]. Moreover, measurement of concentrations of some man-made radio nuclides such as Cs-137 and others in soil is too important to evaluate the contribution of

Keywords

natural radioactivity, Cs-137 fallout, NORM, radioactivity level in soil, Saudi Arabia