Natural Radioactivity Measurements in Soil, External Dose and Radiological Hazard Assessment in the Uranium and Thorium Bearing Region of Lolodorf, Cameroon

Nkoulou, Joseph Emmanuel Ndjana; Talla, Simplice Feutseu; Bineng, Guillaume Samuel; Manga, André; Siaka, Yvette Flore Tchuente; Saïdou, -

doi:10.3769/radioisotopes.67.435

Cited by 12 publications

(7 citation statements)

References 22 publications

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“…The characteristics of the dwellings selected in this study also justify their high values. In addition, previous study carried out in the same study areas of this study revealed the presence of the anomaly of 232 Th and 238 U at some specific points in the region (24,27,28). However, the literature (29) has revealed a strong link between EETC on the one hand, and type of architecture, geology, climate and people's lifestyle on the other.…”

Section: Radon Thoron and Thoron Progeny Concentrationssupporting

confidence: 41%

The Importance of Direct Progeny Measurements for Correct Estimation of Effective Dose Due to Radon and Thoron

Bineng

Saïdou

Tokonami

et al. 2020

Front. Public Health

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Radon (Rn), thoron (Tn), and thoron progeny (TnP) were measured in seven inhabited areas of the uranium and thorium bearing region of Lolodorf, located in southwestern Cameroon. Then the equilibrium factor (F Tn ) between thoron and its progeny was determined in order to show the importance of direct progeny measurements for correct estimation of effective dose due to radon, thoron and their progenies. A total of 220 RADUET detectors were used to measure indoor radon and thoron and 130 TnP monitors for thoron progeny indoors. The arithmetic and geometric mean concentrations of Rn, Tn, and TnP were 103 and 89 Bq m −3 , 173, and 118 Bq m −3 , 10.7, and 7.4 Bq m −3 , respectively. Total effective dose determined from radon, thoron, and their progenies was estimated at 4.2 ± 0.5 mSv y −1 . Thoron equilibrium factor varied according to seasons, the type of dwelling, building materials and localities. Thoron (Tn and TnP) contribution to effective dose ranged between 3 and 80% with the average value of 53%. Total effective dose estimated from the world average equilibrium factor of 0.02 given by UNSCEAR was 2.7 ± 0.2 mSv y −1 . The effective dose due to thoron varied greatly according to the different values taken by F Tn and was different from that determined directly using TnP concentrations. Thus, effective dose due to thoron determined from the equilibrium factor is unreliable. Therefore, the risk of public exposure due to thoron (Tn and TnP) may therefore be higher than that of radon (Rn and RnP) in many parts of the world if F Tn is no longer used in estimating total effective dose. This is not in contradiction with the UNSCEAR conclusions. It is therefore important to directly measure the radon and thoron progeny for a correct estimate of effective dose.

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Section: Radon Thoron and Thoron Progeny Concentrationssupporting

confidence: 41%

The Importance of Direct Progeny Measurements for Correct Estimation of Effective Dose Due to Radon and Thoron

Bineng

Saïdou

Tokonami

et al. 2020

Front. Public Health

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“…The longer experiment, the more accurate spectrum and thus better assessment of the radioactivity concentration. Typical time e.g., for soil radioactivity measurements varies from several up to 72 h, see [20,[36][37][38].…”

Section: Discussionmentioning

confidence: 99%

“…The dried dust was sieved through 2 mm sieves. This procedure assures quite good homogeneity of the samples for testing the radioactivity concentrations, [15][16][17][18][19][20]. The samples prepared in this way were then poured into 1.5 dm 3 cylindrical Marinelli beakers, then placed under the spectrometer probe.…”

Section: Sample Preparation For Gamma Spectrometrymentioning

confidence: 99%

Assessment of the Natural Radioactivity of Polish and Foreign Granites Used for Road and Lapidary Constructions in Poland

et al. 2020

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The measurements of the specific activity of natural radioactive isotopes of radium (226Ra), thorium (232Th) and potassium (40K) in chosen samples of imported (China, Finland, Spain, India, Sweden) and Polish (Izerski, Karkonosze, Siedlimowicki, Strzegomski, Strzelinski) granites were performed. The measurements were carried out with 2 × 2” NaI(Tl) scintillation detector. The measured specific activity on natural radioactive isotopes were within the following ranges: 5.8–312 [Bq kg−1], 5.5–189 [Bq kg−1] and 109–1590 [Bq kg−1] for 226Ra, 232Th and 40K, respectively. Obtained concentrations of radioactive isotopes allowed to perform the analysis of the exposure of the humans from the ionizing radiation emitted by the granites. The determination of the exposure consisted in the calculation of absorbed gamma dose rate (D) [nGy h−1] for each sample, which fell in the range between 20 and 511 [nGy h−1], annual effective dose rate (AED) [mSv year−1] ranging between 0.10 and 2.50 [mSv year−1], radium equivalent activity (Raeq) [Bq kg−1] with values between 22 and 570 [Bq kg−1], external and internal hazard indices (Hex) and (Hin) falling in the ranges 0.06−1.53 and 0.08–2.41 respectively, as well as gamma (Iγ) and alpha (Iα), representative level indices with values 0.08–2.0 and 0.029–1.56, respectively. Moreover, obtained results were compared with the international standard values given by the European Commission (EC), the United Nations Scientific Committee on the Effects of Atomic Radiation given in UNSCEAR Reports, and the results of research from other laboratories.

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“…It was stated that the construction year of the building had the highest impact on the difference in indoor radon concentration among schools. According to the results of indoor radon measurements conducted in Cameroon, the average indoor radon concentration value exhibited a low-risk level compared to the permissible limits, with a value of 42 Bqm −3 [241]. The annual arithmetic average of the radon concentration in Beijing obtained was 42 ± 13.7 Bqm −3 [242].…”

Section: Indoor Radon Concentrationmentioning

confidence: 97%

Radon, Concrete, Buildings and Human Health—A Review Study

Bulut,

Şahin

2024

Buildings

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A comprehensive evaluation of the results obtained according to the measurement of radon gas in buildings and concrete, which is the most consumed material in the world after water, in accessible studies carried out in the last 40 years is the main objective of this study. The paper additionally aims to address the gap in the literature by comparatively determining which parameters affect radon–concrete and radon–building relationships. The scientific knowledge compiled within the scope of this article was presented under the main headings of radon and radon gas measurements in concrete and buildings. Radon gas, also known as the “invisible killer”, is considered the second most important cause of lung cancer after smoking (the gas is responsible for 3–14% of lung cancer cases in the world). The results determined that radon concentration limits have been applied in the range of 100–400 Bqm−3 in houses and 100–3700 Bqm−3 in workplaces. Studies conducted on the exhalation rate of radon showed that the radon exhalation rate of concrete may be in the range of 0.23–510 Bqm−2 h−1. The results of indoor radon concentration measurements revealed that values between 4.6 Bqm−3 and 583 Bqm−3 were obtained. Despite the existing literature, some researchers state that there is an urgent need for an improved and widely accepted protocol based on reliable measurement techniques to standardize measurements of the radon exhalation rate of construction materials and the indoor radon concentration of buildings.

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Natural Radioactivity Measurements in Soil, External Dose and Radiological Hazard Assessment in the Uranium and Thorium Bearing Region of Lolodorf, Cameroon

Cited by 12 publications

References 22 publications

The Importance of Direct Progeny Measurements for Correct Estimation of Effective Dose Due to Radon and Thoron

The Importance of Direct Progeny Measurements for Correct Estimation of Effective Dose Due to Radon and Thoron

Assessment of the Natural Radioactivity of Polish and Foreign Granites Used for Road and Lapidary Constructions in Poland

Radon, Concrete, Buildings and Human Health—A Review Study

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