Assessment of radon exhalation rates in mineral rocks used in building decoration in Nigeria

The recent interest in the applications of mineral rocks for interior building decoration has been a major concern from the radiological perspective because the breaking down of rocks into various shapes and sizes releases radioactive gaseous element that is harmful to human health. Hence, this study assessed the radon exhalation rates of different rock types in Nigeria and their implications on human health. A total of 45 samples comprising five samples per rock type were prepared, packed, and sealed inside a modified closed can and thereafter subjected to radon concentration measurement using a RAD7 detector. The results of the study showed that granite and limestone rock types had high radon concentrations and exhalation rates as compared to other rock samples assessed. The radon concentration for granite and limestone rockfalls within the action level limit. Thus, effort should be made to ensure adequate ventilation of any building that uses these rock types in building decoration. The results obtained can be used as baseline data for future investigation of the rock types in any locality.