Assessment of natural radioactivity and its radiological hazards in several types of cement used in Senegal
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Assessment of natural radioactivity and its radiological hazards in several types of cement used in Senegal Ousmane Ndour1 · Coumba Thiandoume1 · Alassane Traore2 · Xavier Cagnat3 · Papa Mbaye Diouf1 · Maurice Ndeye4 · Ababacar Sadikhe Ndao2 · Adams Tidjani1 Received: 28 August 2020 / Accepted: 18 November 2020 © Springer Nature Switzerland AG 2020
Abstract In this study, the activity concentrations of 226Ra, 232Th and 40K in twenty cement samples of four types (CEM, CEM II, CEM III, and CEM IV) collected from building material suppliers in Senegal were measured using a low-background digital gamma-ray spectrometer equipped with broad energy germanium detector. The activity concentrations of 226Ra, 232Th and 40K varied from 7.1–150.3 Bq kg−1, 3.7–16.1 Bq kg−1, and 48.7–133.9 Bq kg−1, respectively. Also, possible radiological risks from the usage of these materials were assessed by estimating external and internal index, indoor absorbed gamma dose rate and the corresponding annual effective dose, effective dose rate to different body organs and tissus, and excess lifetime cancer risk. The estimated radiological hazard indices were revised in light of the relevant national and international legislation and guidance. The values of the radiological hazard indices were found to be within relevant all limit values for structural building materials. Keywords Natural radiouclides · Gamma-ray spectrometry · Activity concentrations · radiological hazards indices · Cement
1 Introduction Humans are continuously exposed to natural radiation which comes from cosmogenic radionuclides and primordial radionuclides [1]. The cosmogenic radionuclides are continuously produced in the upper part of the atmosphere by the interaction of the cosmic radiation with atoms or molecules. The primordial radionuclides are the uranium series with as parent the 238U, 235U series or actinium series, thorium (232Th) series, and 40K which is a non-series of disintegration. When dealing with naturally occurring radioactive material (NORM), only the primordial radionuclides are of radiological interest. Depending on the geological origin of the raw materials (rocks, soil, and industrial products), the building materials may
contain different amounts of natural radionuclides [2, 3]. As cement is most used in building material, it can become a health and environmental problem for the population. According to Mansoor et al., individuals spend 80% of their time at home or office indoor [4]. It is then important to estimate the natural radioactivity in cement. There are different exposition ways of humans by radionuclides content in cement: internal and external exposure. Internal exposure is due to the inhalation of radon (222Rn) which emanates from the building material [5]. During the inhalation, radon may decay in the track respiratory conducting to the deposition of its progenies and becomes a permanent source of internal exposure [6]. External exposure is due to the emission of γ-rays by
* Ousmane Ndour, [email protected] | 1Natural an
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