Determination of natural radioactivity in soils of Henties Bay, Namibia.

Abstract

The concentrations of naturally occurring radionuclides 40K, 238U and 232Th in soil samples collected across the town of Henties Bay in Western Namibia have been determined and used to estimate a baseline natural radiation level in the town. These concentrations were measured using an HPGe detector and found to vary from 790.2±31.6 Bq kg−1 to 1039.0±38.7 Bq kg−1 with a mean of 936.1±68.5 Bq kg−1 for 40K, 36.2±2.6 Bq kg−1 to 153.4±4.8 Bq kg−1 with a mean of 62.2±20.0 Bq kg−1 for 238U and 50.4±4.5 Bq kg−1 to 323.6±12.7 Bq kg−1 with a mean of 97.1±44.7 Bq kg−1 for 232Th. The corresponding effective dose rate obtained from the radionuclides is 0.16±0.04 mSv y−1. This dose rate is well below the limit of 1.0 mSv y−1 recommended for the public by the International Commission on Radiological Protection (ICRP) and indicates that the town has a normal background radiation.