Distribution of Gamma-Emitting Radionuclides in the Soils of the Neudamm Campus of the University of Namibia, Windhoek, Namibia

Abstract

The concentrations of naturally occurring radionuclides40K,232Th and238U in soil samplestaken from the Neudamm campus of the University of Namibia, Windhoek, Namibia have beendetermined and used to calculate a mean annual effective dose for the campus. The concen-trations were measured using a sensitive gamma-ray spectroscopic system consisting of a highpurity germanium detector and associated equipment.40K was found to have the highest specificconcentration varying between 229.1±13.5 Bq kg−1and 499.0±16.5 Bq kg−1with a meanvalue of 364.5±79.3 Bq kg−1while the concentration of232T hvaries between 10.4±2.8 Bqkg−1and 38.5±3.8 Bq kg−1with a mean value of 28.0±9.2 Bq kg−1and the concentration of238U varies between 11.7±1.3 Bq kg−1and 24.7±2.1 Bq kg−1with a mean value of 18.5±4.8Bq kg−1. The value of 0.05±0.01 mSv y−1obtained for the mean annual effective dose is wellbelow the limit of 1 mSv y−1recommended for the public by the International Commission onRadiological Protection. This result indicates that radiation hazard is negligible on the campus