Natural Radioactivity and Associated Radiation Hazards in Samples of Maize Available to the People of KwaZulu-Natal, South Africa

Abstract

Ingestion of foods and drinking water is considered the leading cause of human exposure to radioactive elements that guide to internal radiation doses. The concentrations and distributions of natural radionuclides 238U, 232Th, and 40K in samples of yellow maize directly consumed in the KwaZulu-Natal province of South Africa were determined to estimate possible radiological hazards to human health. Representative samples collected from towns in six regions of the province were analyzed using a Canberra-supplied broad energy hyper pure germanium (HPGe) detector. The mean activity concentrations were 21.3, 26.0, 21.0, 52.0, 53.3, and 80.7 Bq/kg for 238U, and 203.3, 386.7, 183.3, 336.7, 320.0, and 526.7 Bq/kg for 40K. 232Th was not detected in any of the maize samples from the studied locations. The estimated effective ingestion doses and the lifetime cancer risks due to 238U and 40K were within internationally recommended limits of 1 mSv and 10–3 for members of the public. However, the values obtained seem high in some locations, particularly for a single diet intake. This finding is part of the radiological baseline information of the KwaZulu-Natal province and, in general, South Africa from maize consumption.