Natural radionuclide analysis in building materials used in Bursa

Building materials are one of the important sources that affect the level of natural radiation exposure in indoor environments, and the naturally occurring radionuclides present in these materials may pose potential radiological risks to human health. In this study, a total of 27 samples were randomly collected in Bursa, construction materials such as cement, brick, sand and plaster as well as surface finished like marble, tile and joint filler. Activity concentrations of 226Ra, 232Th and 40K in the samples were measured using a 3"x3" NaI (Tl) gamma-ray spectrometer. It was determined that the activity concentrations of 226Ra, 232Th and 40K activity concentrations in building materials analyzed within scope of the study ranged below detection limit (BDL)-81.16 Bqkg-1, BDL-94.22 Bqkg-1, BDL-781.26 Bqkg-1, respectively. The highest average activity concentrations of 226Ra and 232Th were found in the cement samples, with 33.6 Bqkg-1 and 43.2 Bqkg-1, respectively, while the highest average value measured for 40K belongs to brick samples with 771.2 Bqkg-1. In addition, to evaluate the radiological hazards in the samples, the activity concentrations obtained were used to calculate the radium equivalent activity (Raeq), the absorbed dose rate in the indoor air (Din), the annual effective dose equivalent (AEDE), external hazard index (Hex), the internal hazard index (Hin) and the gamma index (Iγ). The Raeq values are below the internationally recognized limit value of 370 Bqkg-1. Except for the Cement 2, Cement 4 and Cement 7 samples, the Din values of all other building materials are within the acceptable limit. The calculated AEDE, Hin, Hex and Iγ values for these building materials are below the recommended unit limit and do not pose a radiological risk. Considering these properties, the materials in question are suitable for use as building materials.