Gamma-ray spectroscopy based on a 100% efficiency hyper-pure germanium detector was used to evaluate the activity concentrations of <sup>226</sup>Ra, <sup>232</sup>Th, and <sup>40</sup...Gamma-ray spectroscopy based on a 100% efficiency hyper-pure germanium detector was used to evaluate the activity concentrations of <sup>226</sup>Ra, <sup>232</sup>Th, and <sup>40</sup>K natural radionuclides in sedimentary, conglomerate, igneous and sedi-ments rock samples collected from four different locations in Eastern desert in Egypt. The obtained activity concentrations are used to evaluate the radi-ological hazards indices, absorbed dose rate, annual effective dose equivalent in air, radium equivalent, external and internal hazard index, radiation level index, annual gonadal dose equivalent, excess lifetime cancer risk and expo-sure rate. The results show that 1) the absorbed dose rate depends on the rock type, 2) the annual effective dose equivalent in air in 71% of sample below 20 mSvy<sup>-1</sup> (permissible limit for workers), 3) the conglomerate rocks show low radioactivity level, 4) sedimentary rocks are rich in radium while igneous rocks are rich in thorium and the sediments rocks are rich in both radium and thorium.展开更多
Twenty-eight environmental samples (eight well water, sixteen granitic rocks and four soils) were collected from different parts of Adham governorate (Adham, Haqal and Al-Jaizah), to assess the radiological hazard and...Twenty-eight environmental samples (eight well water, sixteen granitic rocks and four soils) were collected from different parts of Adham governorate (Adham, Haqal and Al-Jaizah), to assess the radiological hazard and cancer risk from different perspectives. Adham is situated in a valley between two granitic mountain chains, where much of water supply for drinking, house use and irrigation comes from wells collecting water rains. The activity concentrations of naturally occurring <sup>40</sup>K, <sup>226</sup>Ra and <sup>232</sup>Th and radionuclides were measured by gamma-ray spectrometry for all samples using RGK-1, RGU-1 and RGTh-1, IAEA reference standards issued by the International Atomic Energy Agency, for detector efficiency calibration. The measured values were utilized to evaluate the internal and external exposures both outdoors and indoors. Different standard room models were adopted for this respect to evaluate the indoor gamma-rays exposure from construction materials as well as internal exposure to radon gas emanating from them. Radon concentration indoors, exceeded the upper reference level in dwellings set at 300 Bq/m<sup>3</sup> by the world health organization, in many scenarios. The mean value of the total excess lifetime cancer risk (due to external exposure from gamma-rays) was 2.29 × 10<sup>-3</sup>, above the world average value of 1.45 × 10<sup>-3</sup>. Furthermore, the measured radon concentrations in all water samples exceeded the EPA (Environmental Protection Agency) 11.1 Bq·L<sup>-1</sup> standard for drinking water, ranging from 12 to 38 Bq·L<sup>-1</sup> with a mean value of 27 Bq·L<sup>-1</sup>. The total annual effective dose (due to inhalation and ingestion) from radon in water, ranged from 58 to 192 μSv/y (for adults) exceeding the international permissible limit of 100 μSv/y, in seven out of eight samples. According to obtained results, the internal exposure from radon in directly used water from wells, might be the major reason of any suspected radiological health haza展开更多
The Uranium-238 (<sup>238</sup>U), Thorium-232 (<sup>232</sup>Th) families and Potassium-40 (<sup>40</sup>K) are of terrestrial origin and contribute generally to an individual’s e...The Uranium-238 (<sup>238</sup>U), Thorium-232 (<sup>232</sup>Th) families and Potassium-40 (<sup>40</sup>K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides<sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.展开更多
Fourteen samples of marble were collected from different factories in Egypt. The samples were crushed, dried in controlled furnace for around twenty four hours, and then stored for five weeks in plastic Marinelli beak...Fourteen samples of marble were collected from different factories in Egypt. The samples were crushed, dried in controlled furnace for around twenty four hours, and then stored for five weeks in plastic Marinelli beakers. Concentrations and the U- and Th-bearing minerals were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS).The gamma radiation of the samples was measured, employing high resolution γ-ray spectroscopy with an accumulating time for about 80000 sec. each. From the measured γ -ray spectra, activity concentrations were determined for marble samples 226Ra (37. 6 ± 1.7 - 100.54 ± 3.2 Bq/kg), 232Th (3.57 ± 0.64 - 9.37 ± 1.80 Bq/kg) and 40K (30.68 ± 1.1 – 1196 ± 4.9 Bq/kg). The absorbed dose rates, annual effective dose rates, radium equivalent activities as well as the radiation hazard indices were estimated. The radium equivalent activities (Raeq) are lower than the limit of 370 Bq kg?1 set by the Organization for Economic Cooperation and Development (Exposure to radiation from the natural radioactivity in building materials. Report by a Group of Experts of the OECD, Nuclear Energy Agency, OECD, Paris, 1979) [1]. All obtained results referred to the fact that all the concentrations were within the allowed limits to domestic use. Comparing the results in this work with those published by International Atomic Energy Agency and local and universal researches, it was found that these concentrations were within the allowed limits for agricultural and domestic uses.展开更多
文摘Gamma-ray spectroscopy based on a 100% efficiency hyper-pure germanium detector was used to evaluate the activity concentrations of <sup>226</sup>Ra, <sup>232</sup>Th, and <sup>40</sup>K natural radionuclides in sedimentary, conglomerate, igneous and sedi-ments rock samples collected from four different locations in Eastern desert in Egypt. The obtained activity concentrations are used to evaluate the radi-ological hazards indices, absorbed dose rate, annual effective dose equivalent in air, radium equivalent, external and internal hazard index, radiation level index, annual gonadal dose equivalent, excess lifetime cancer risk and expo-sure rate. The results show that 1) the absorbed dose rate depends on the rock type, 2) the annual effective dose equivalent in air in 71% of sample below 20 mSvy<sup>-1</sup> (permissible limit for workers), 3) the conglomerate rocks show low radioactivity level, 4) sedimentary rocks are rich in radium while igneous rocks are rich in thorium and the sediments rocks are rich in both radium and thorium.
文摘Twenty-eight environmental samples (eight well water, sixteen granitic rocks and four soils) were collected from different parts of Adham governorate (Adham, Haqal and Al-Jaizah), to assess the radiological hazard and cancer risk from different perspectives. Adham is situated in a valley between two granitic mountain chains, where much of water supply for drinking, house use and irrigation comes from wells collecting water rains. The activity concentrations of naturally occurring <sup>40</sup>K, <sup>226</sup>Ra and <sup>232</sup>Th and radionuclides were measured by gamma-ray spectrometry for all samples using RGK-1, RGU-1 and RGTh-1, IAEA reference standards issued by the International Atomic Energy Agency, for detector efficiency calibration. The measured values were utilized to evaluate the internal and external exposures both outdoors and indoors. Different standard room models were adopted for this respect to evaluate the indoor gamma-rays exposure from construction materials as well as internal exposure to radon gas emanating from them. Radon concentration indoors, exceeded the upper reference level in dwellings set at 300 Bq/m<sup>3</sup> by the world health organization, in many scenarios. The mean value of the total excess lifetime cancer risk (due to external exposure from gamma-rays) was 2.29 × 10<sup>-3</sup>, above the world average value of 1.45 × 10<sup>-3</sup>. Furthermore, the measured radon concentrations in all water samples exceeded the EPA (Environmental Protection Agency) 11.1 Bq·L<sup>-1</sup> standard for drinking water, ranging from 12 to 38 Bq·L<sup>-1</sup> with a mean value of 27 Bq·L<sup>-1</sup>. The total annual effective dose (due to inhalation and ingestion) from radon in water, ranged from 58 to 192 μSv/y (for adults) exceeding the international permissible limit of 100 μSv/y, in seven out of eight samples. According to obtained results, the internal exposure from radon in directly used water from wells, might be the major reason of any suspected radiological health haza
文摘The Uranium-238 (<sup>238</sup>U), Thorium-232 (<sup>232</sup>Th) families and Potassium-40 (<sup>40</sup>K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides<sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.
文摘Fourteen samples of marble were collected from different factories in Egypt. The samples were crushed, dried in controlled furnace for around twenty four hours, and then stored for five weeks in plastic Marinelli beakers. Concentrations and the U- and Th-bearing minerals were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS).The gamma radiation of the samples was measured, employing high resolution γ-ray spectroscopy with an accumulating time for about 80000 sec. each. From the measured γ -ray spectra, activity concentrations were determined for marble samples 226Ra (37. 6 ± 1.7 - 100.54 ± 3.2 Bq/kg), 232Th (3.57 ± 0.64 - 9.37 ± 1.80 Bq/kg) and 40K (30.68 ± 1.1 – 1196 ± 4.9 Bq/kg). The absorbed dose rates, annual effective dose rates, radium equivalent activities as well as the radiation hazard indices were estimated. The radium equivalent activities (Raeq) are lower than the limit of 370 Bq kg?1 set by the Organization for Economic Cooperation and Development (Exposure to radiation from the natural radioactivity in building materials. Report by a Group of Experts of the OECD, Nuclear Energy Agency, OECD, Paris, 1979) [1]. All obtained results referred to the fact that all the concentrations were within the allowed limits to domestic use. Comparing the results in this work with those published by International Atomic Energy Agency and local and universal researches, it was found that these concentrations were within the allowed limits for agricultural and domestic uses.
