New articles published: V. 14 n. 2 (2026)
Assessment of Terrestrial Radionuclides and Radiological Risk within Indigenous Construction Materials: A Case Study from the Liwale District, Tanzania
Abstract:Prolonged indoor exposure to radiation presents a public health concern, primarily due to building materials containing significant concentrations of natural radionuclides. This study was initiated in response to a documented case of elevated indoor gamma radiation in the Liwale District. The research aims to assess natural radioactivity levels in building materials sourced from this district, which is characterized by Hypoluvic Arenosols and Profondic/Arenic Luvisols derived from continental Neogene sandstone deposits, and to evaluate their potential radiological hazards. The radionuclide levels in 25 samples comprising sand, clay, and gravel were analyzed using a gamma-ray spectrometer coupled with a high-purity germanium (HPGe) detector. The average activity concentrations of 226Ra, 232Th, and 40K were 40.8±2.5 Bq kg-1, 114.9±4.1 Bq kg-1, and 311.9±14.5 Bq kg-1, respectively; Whilst 40K levels were typical, the values for 226Ra and 232Th exceeded the UNSCEAR world averages. Moreover, average values for radiological hazard indices were: Raeq, 229.1±9.6 Bq kg-1; Hex, 0.6; I, 0.8, and Eff, 0.5 mSv y-1. Notably, the average values of all indices were within their internationally recommended limits, indicating a low overall radiological risk. Nevertheless, 20% of the samples (5 out of 25) exceeded the safety thresholds for Raeq, Hex, and I, whilst 16% (4 out of 25) surpassed the limit for Eff. This signifies potential lithogenic hazards associated with the use of these building materials. Therefore, this study strongly recommends implementing stringent regulatory screening and control measures for local building materials sourced from these specific geological formations. Read full article.
