Assessment of Natural Radioactivity and Associated Radiological Risks in Cements Produced and Used as Building Materials in Malawi

Aeron M A Nahuku, Alinue Musopole, Samson Nyirenda, Fabiano G D Thulu, Estiner W Katengeza, Bernard Thole, and Chikumbusko C Kaonga
2026-05-22 6 views 0 downloads

 

This study assessed the natural radioactivity and associated radiological health risks of commercially available cement brands produced and distributed in Malawi to evaluate compliance with international radiation safety standards for building materials. Cement samples were analyzed for 226Ra, 232Th, and 40K activity concentrations using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were 29.9 ± 4.6, 17.3 ± 2.8, and 309.7 ± 34.8 Bq kg?1, respectively, all below the UNSCEAR recommended limits. The mean radium equivalent activity (Raeq) was 78.4 ± 8.5 Bq kg?1, significantly lower than the recommended limit of 370 Bq kg?1. Calculated radiological hazard indices, including external hazard index, internal hazard index, gamma index, and alpha index, were all below the recommended safety threshold of unity. The mean outdoor and indoor absorbed dose rates were 36.2 ± 8.5 and 72.5 ± 7.5 nGy h?1, respectively, while the corresponding annual effective doses were 0.044 ± 0.0046 and 0.178 ± 0.019 mSv y?1. The evaluated excess life cancer risk values were well below internationally accepted reference limits. These results demonstrate that the investigated cement products do not pose significant radiological hazards to the public and are safe for use as construction material. However, periodic assessment and monitoring of these natural radionuclides in cements and other building materials in Malawi are highly recommended.

 

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