Health risk evaluation of radon progeny exposure in Nigerian traditional mud houses

Abstract

In a study of 56 randomly selected Traditional Mud Houses (TMHs) in Nigeria, the radiation health impacts of radon progeny were evaluated using CR-39 radon detectors within a rainy season. The measured radon concentration ranged from 17 to 174 Bq m-3, with an average value of 76 Bq m-3 (SD = 36). This was lower than the WHO’s recommended reference level of 100 Bq m-3. However, 24% of the surveyed houses exceeded this level, indicating potential health risks. The estimated Potential Alpha Energy Concentration (PAEC) due to its progeny ranged from 1.84 to 18.81 mWL with an average value of 8.24 mWL (SD=3.91). The computed annual effective doses yielded an average value of 3.06 ± 1.44 mSv y1, which is far less than the recommended reference level of 10 mSv y1 by the International Commission on Radiological Protection. The lifetime excess absolute risks varied from 0.4 × 104 to 3.9 × 104, with an average of 1.7 ± 0.8 × 104. Improved the ventilation systems, the application of cements plaster and distempers to the building walls and floor were recommended for older TMHs with ages greater than 50 y to mitigate radon exposure. This data can inform potential policy measures for indoor radon progeny control in Nigeria.