Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon
Indoor radon, thoron and thoron progeny concentrations, along with the equilibrium factor for thoron progeny and soil gas radon concentrations, have been measured to assess radiological risks in the centre and south regions of Cameroon. Indoor radon and thoron concentrations were estimated using rad...
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MDPI AG
2023-11-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/14/12/1708 |
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| author | Atangana Bingana Martin Serge Takoukam Soh Serge Didier Bineng Guillaume Samuel Chutima Kranrod Yasutaka Omori Masahiro Hosoda Saïdou Shinji Tokonami |
| author_facet | Atangana Bingana Martin Serge Takoukam Soh Serge Didier Bineng Guillaume Samuel Chutima Kranrod Yasutaka Omori Masahiro Hosoda Saïdou Shinji Tokonami |
| author_sort | Atangana Bingana Martin Serge |
| collection | DOAJ |
| description | Indoor radon, thoron and thoron progeny concentrations, along with the equilibrium factor for thoron progeny and soil gas radon concentrations, have been measured to assess radiological risks in the centre and south regions of Cameroon. Indoor radon and thoron concentrations were estimated using radon–thoron discriminative detectors (RADUET), while thoron progeny monitors measured the equilibrium equivalent thoron concentration (EETC). Radon concentrations in the soil were determined using a MARKUS 10 detector. It was found that radon, thoron and thoron progeny concentrations range between 19 and 62 Bq m<sup>−3</sup>, 10 and 394 Bq m<sup>−3</sup> and 0.05 and 21.8 Bq m<sup>−3</sup>, with geometric means of 32 Bq m<sup>−3</sup>, 98 Bq m<sup>−3</sup> and 4.9 Bq m<sup>−3</sup>, respectively. The thoron equilibrium factor ranges between 0.007 and 0.24, with an arithmetic mean of 0.06 ± 0.03; this is higher than the world average value of 0.02 provided by the United Nations Scientific Commission on the Effects of Atomic Radiation(UNSCEAR, New York, USA). The level of the soil radon concentration ranges from 4.8 to 57.3 kBq m<sup>−3</sup>, with a geometric mean of 12.1 kBq m<sup>−3</sup> at a depth of 0.7 m. Of the sampling points, 66% fall within normal radon risk areas, and 3% of the sampling areas are high radon risk areas exceeding 50 kBq m<sup>−3</sup>. The annual effective dose was found to be 0.03 ± 0.01 mSv for radon, 0.08 ± 0.05 mSv for thoron, 0.63 ± 0.12 mSv for radon progeny and 1.40 ± 0.84 mSv for thoron progeny. The total dose is estimated to be 2.14 mSv y<sup>−1</sup>. The mean estimated indoor excess lifetime cancer risk values due to radon, thoron, radon progeny and thoron progeny are 0.12 × 10<sup>−3</sup>, 0.31 × 10<sup>−3</sup>, 2.51 × 10<sup>−3</sup> and 5.58 × 10<sup>−3</sup>, respectively. Thoron progeny contributed 60% to the effective dose. Thus, thoron progeny cannot be neglected in dose assessments, in order to avoid biased results in radio-epidemiological studies. |
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| spelling | doaj.art-96594d18fcbf45d09ed9788cb7fc2e632023-12-22T13:52:37ZengMDPI AGAtmosphere2073-44332023-11-011412170810.3390/atmos14121708Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of CameroonAtangana Bingana Martin Serge0Takoukam Soh Serge Didier1Bineng Guillaume Samuel2Chutima Kranrod3Yasutaka Omori4Masahiro Hosoda5Saïdou6Shinji Tokonami7Physics Laboratory, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 812, CameroonUniversity Institute of Wood Technology, University of Yaounde I, Mbalmayo P.O. Box 306, CameroonPhysics Laboratory, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 812, CameroonInstitute of Radiation Emergency Medicine, Hirosaki University, Hirosaki City, Aomori 036-8564, JapanInstitute of Radiation Emergency Medicine, Hirosaki University, Hirosaki City, Aomori 036-8564, JapanInstitute of Radiation Emergency Medicine, Hirosaki University, Hirosaki City, Aomori 036-8564, JapanPhysics Laboratory, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 812, CameroonInstitute of Radiation Emergency Medicine, Hirosaki University, Hirosaki City, Aomori 036-8564, JapanIndoor radon, thoron and thoron progeny concentrations, along with the equilibrium factor for thoron progeny and soil gas radon concentrations, have been measured to assess radiological risks in the centre and south regions of Cameroon. Indoor radon and thoron concentrations were estimated using radon–thoron discriminative detectors (RADUET), while thoron progeny monitors measured the equilibrium equivalent thoron concentration (EETC). Radon concentrations in the soil were determined using a MARKUS 10 detector. It was found that radon, thoron and thoron progeny concentrations range between 19 and 62 Bq m<sup>−3</sup>, 10 and 394 Bq m<sup>−3</sup> and 0.05 and 21.8 Bq m<sup>−3</sup>, with geometric means of 32 Bq m<sup>−3</sup>, 98 Bq m<sup>−3</sup> and 4.9 Bq m<sup>−3</sup>, respectively. The thoron equilibrium factor ranges between 0.007 and 0.24, with an arithmetic mean of 0.06 ± 0.03; this is higher than the world average value of 0.02 provided by the United Nations Scientific Commission on the Effects of Atomic Radiation(UNSCEAR, New York, USA). The level of the soil radon concentration ranges from 4.8 to 57.3 kBq m<sup>−3</sup>, with a geometric mean of 12.1 kBq m<sup>−3</sup> at a depth of 0.7 m. Of the sampling points, 66% fall within normal radon risk areas, and 3% of the sampling areas are high radon risk areas exceeding 50 kBq m<sup>−3</sup>. The annual effective dose was found to be 0.03 ± 0.01 mSv for radon, 0.08 ± 0.05 mSv for thoron, 0.63 ± 0.12 mSv for radon progeny and 1.40 ± 0.84 mSv for thoron progeny. The total dose is estimated to be 2.14 mSv y<sup>−1</sup>. The mean estimated indoor excess lifetime cancer risk values due to radon, thoron, radon progeny and thoron progeny are 0.12 × 10<sup>−3</sup>, 0.31 × 10<sup>−3</sup>, 2.51 × 10<sup>−3</sup> and 5.58 × 10<sup>−3</sup>, respectively. Thoron progeny contributed 60% to the effective dose. Thus, thoron progeny cannot be neglected in dose assessments, in order to avoid biased results in radio-epidemiological studies.https://www.mdpi.com/2073-4433/14/12/1708<sup>222</sup>Rn<sup>220</sup>Rnsoil gas radoninhalation doseequilibrium factorexcess lifetime cancer risk (ELCR) |
| spellingShingle | Atangana Bingana Martin Serge Takoukam Soh Serge Didier Bineng Guillaume Samuel Chutima Kranrod Yasutaka Omori Masahiro Hosoda Saïdou Shinji Tokonami Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon Atmosphere <sup>222</sup>Rn <sup>220</sup>Rn soil gas radon inhalation dose equilibrium factor excess lifetime cancer risk (ELCR) |
| title | Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon |
| title_full | Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon |
| title_fullStr | Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon |
| title_full_unstemmed | Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon |
| title_short | Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon |
| title_sort | assessment of radiological risks due to indoor radon thoron and progeny and soil gas radon in thorium bearing areas of the centre and south regions of cameroon |
| topic | <sup>222</sup>Rn <sup>220</sup>Rn soil gas radon inhalation dose equilibrium factor excess lifetime cancer risk (ELCR) |
| url | https://www.mdpi.com/2073-4433/14/12/1708 |
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