Abstract
The change of natural ionizing radiation and the radon exhalation rates from typical building materials in underground parking lots are presented in the article. The activity concentration of natural radionuclides 232Th, 226Ra, and 40K in six important types of construction materials, which are mostly used in Lithuania, were analyzed using high-resolution gamma spectroscopy. The highest values were found in concrete and ferroconcrete samples: 226Ra 44 and 90 Bq kg−1; 232Th 29 and 34 Bq kg−1; 40K 581 and 603 Bq kg−1. A strong positive correlation (0.88) was observed between radium activity concentration and radon concentration. The activity indexes (Iα and Iγ) and radium equivalent activity (Req) evaluating the suitability of materials for such constructions from the view of radiation safety were determined. The average values of the calculated absorbed dose rate in samples ranged from 18.24 nGy h−1 in the sand to 87.26 nGy h−1 in ferroconcrete. The calculated annual effective dose was below the limit of 1.0 mSv y−1. The values of the external and internal hazards index (Hex and Hin) were all below unity, and the values of Iγ and Iα were below the recommended levels of 0.5 and 1. Dosimetric analysis of underground parking lots was carried out. It was determined that the external equivalent dose rate caused by the 222Rn progeny radiation in the underground car parking lots varies from 17 to 30% of the total equivalent dose rate.
Highlights
Ionizing radiation is one of the factors that can have a negative impact on human health
The results show that radium equivalent activity index (Raeq) of different building materials can vary significantly
Activity concentrations of 40 K, 232 Th, and 226 Ra in the building materials used for construction underground parking lots were determined
Summary
Ionizing radiation is one of the factors that can have a negative impact on human health. Natural radiation such as cosmic radiation, radionuclides in the soil and construction materials, radon gas are the highest sources of human radiation exposure. Even low doses of ionizing radiation can cause chronic diseases, cancer can lead to various negative health effects. 226 Ra, 232 Th, and 40 K in construction materials is an important source of human exposure [1,2]. Gamma radiation of these natural radionuclides causes external exposure
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