Radiological assessment of cement and clay based building materials from southern coastal region of Kerala

372-376Building materials are one of the potential sources of indoor radioactivity because of the naturally occurring radio nuclides in them. External as well as internal exposures are the two pathways of radiation dose imparted to the human beings from the building materials. Natural clay is the main raw material for the production of bricks and tiles. In the present study, samples of cement, bricks, floor and wall tiles have been analyzed for the primordial radio nuclides namely, uranium, thorium and potassium using gamma ray spectrometry. Radon exhalation rates of these materials were also measured. Among the samples analyzed, the minimum radium equivalent activity was found in bricks (66.08 Bqkg−1) and the maximum was found in cement (225.46 Bqkg−1). External gamma dose, effective dose equivalent, internal and external hazard indexes resulting from the radio nuclides were also determined. The radon exhalation rates from building materials were found to vary between 10.5±2.8 and 82.8±8.2 mBqh−1m−2