A set of 8 groups with 239 samples of a total of 49 types of different materials representative of the most commonly used construction materials in low-income dwellings in Brazil was collected from construction materials stores in the state of Rio de Janeiro (Brazil). The radiometric analysis of the NORMs radionuclides (226Ra, 235U, 232Th, and 40K) in the samples was performed by gamma radiation spectrometry. The results of the specific concentrations of the gamma-ray spectra in the area under investigation using a High Purity Germanium (HPGe) detector with 30% efficiency were 26.0 ± 1.1, 25.3 ± 0.4, and 223 ± 14 Bq kg−1 for 226Ra, 232Th, and 40K, respectively. The average values are below the world limit of 50, 50, and 500 Bq kg-1 for 226Ra, 232Th, and 40K, respectively. Only the granite, marble, and quartz samples showed measurable values of 235U, and it was below 5 Bq kg−1. The hazard index for gamma radiation due to the use of Brazilian construction materials (IBRA) was formulated. The average IBRA value was 0.23 ± 0.01. The highest average values above 1 in the IBRA were found in sand, bricks, and gravel, due to the high background of the locations where their raw materials were extracted. Most samples presented an effective dose below the permissible limit value of 1.0 mSv y−1. In general, the materials analyzed in this study can be used in dwelling construction without great radiological risk to the health of the inhabitants.

中文翻译：

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巴西建筑材料新危害指数 （IBRA） 的辐射分析和实施


从里约热内卢州（巴西）的建筑材料商店收集了一组 8 组，共 239 个样本，共 49 种不同材料，代表了巴西低收入住宅中最常用的建筑材料。通过伽马辐射光谱法对样品中的 NORMs 放射性核素 （226Ra、235U、232Th 和 40K） 进行辐射分析。对于226Ra、232Th和40K，使用高纯锗（HPGe）检测器±效率为26.0 Ra、232Th和40K±1.1、25.3 ± 0.4和223 Bq kg-1。对于 50Ra、50Th、232T 和 40K，平均值分别低于 232、232 和 40 Bq kg-1 的世界极限。只有花岗岩、大理石和石英样品显示出 235U 的可测量值，并且低于 5 Bq kg-1。制定了由于使用巴西建筑材料 （IBRA） 引起的伽马辐射的危害指数。平均 IBRA 值为 0.23 ± 0.01。在 IBRA 中，高于 1 的最高平均值出现在沙子、砖块和砾石中，因为其原材料的提取地点具有高背景。大多数样品的有效剂量低于 1.0 mSv y-1 的允许限值。一般来说，本研究中分析的材料可用于住宅建设，对居民的健康没有很大的放射性风险。