Annual Gonadal Dose Equivalent Research Articles

Assessment of natural radioactivity levels in soil samples from some areas in Assiut, Egypt

The natural radioactivity of soil samples from Assiut city, Egypt, was studied. The activity concentrations of 28 samples were measured with a NaI(Tl) detector. The radioactivity concentrations of (226)Ra, (232)Th, and (40)K showed large variations, so the results were classified into two groups (A and B) to facilitate the interpretation of the results. Group A represents samples collected from different locations in Assiut and characterized by low activity concentrations with average values of 46.15 ± 9.69, 30.57 ± 4.90, and 553.14 ± 23.19 for (226)Ra, (232)Th, and (40)K, respectively. Group B represents samples mainly collected from the area around Assiut Thermal Power Plant and characterized by very high activity concentrations with average values of 3,803 ± 145, 1,782 ± 98, and 1,377 ± 78 for (226)Ra, (232)Th, and (40)K, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose rate (E), the external hazard index (H ex), and the annual gonadal dose equivalent (AGDE) have been calculated and compared with the internationally approved values. For group A, the calculated averages of these parameters are in good agreement with the international recommended values except for the absorbed dose rate and the AGDE values which are slightly higher than the international recommended values. However, for group B, all obtained averages of these parameters are much higher by several orders of magnitude than the international recommended values. The present work provides a background of radioactivity concentrations in the soil of Assiut.

Evaluation of NORM and Dose Assessment in an Aluminium Industry in Nigeria

The activity concentrations of natural radionuclides 226Ra, 232Th and 40K in bauxite ore, alumina, dross tailing, aluminium scraps and soil samples collected from an aluminium industry in Nigeria were determined by gamma ray spectroscopy method. The mean values of 226Ra, 232Th and 40K content of the samples ranged from 16 ± 6 (alumina) to 31 ± 10 (scrap), 41 ± 0.12 (scrap) to 134 ± 21(bauxite) and 47 ± 14 (bauxite) to 354 ± 8 (scrap) Bq·kg-1, respectively. The mean activity concentrations of 226Ra and 40K in all the samples are lower than the world average for soil while 232Th is higher with the exception of alumina and scrap. As a measure of radiation hazard to the occupational workers and the members of the public, the radium equivalent activities and external gamma dose rates due to the radionuclides at 1 m above ground surface were calculated. The radium equivalent activities which varied between 88 ± 10 (alumina) and 222 ± 34 (bauxite) Bq·kg-1 are within the safety recommended limit of 370 Bq·kg-1. The mean annual effective doses calculated from the absorbed dose rates in air were between 54 ± 6 (alumina) and 134 ± 20 (bauxite) μSv·y-1, which is lower than the 1 mSv·y-1 recommended for the general public. The annual gonadal dose equivalent of all the samples with the exception of alumina was higher than the world average for soil.

Determination of naturally radioactive elements in chalk sticks by means of gamma spectroscopy

The radiation hazards due to ingestion of chalkboard dust were investigated. Sixteen samples from three different origin fabricates were used. The estimation of radiation hazard indices were based on the evaluation of the concentration activities of the natural radionuclides 238U, 232Th and 40K. The radium equivalent activity, external hazard index, internal hazard index and the annual dose equivalent associated with the radionuclides were calculated and compared with international recommended values to assess the radiation hazard. The values of internal and external radiation hazard indices were found to be less than unity. The annual effective dose rate obtained, E eff, and the annual gonadal dose equivalent (AGDE) are found to be less than the limit of the doses recommended by the International Commission on Radiological Protection for the general public. The analytical results show that besides the main calcium content, some toxic elements, S, Mo and Pb and Ni and Pb, in the Egyptian and imported chalk stocks, respectively, existed.

Assessment of the natural radioactivity using two techniques for the measurement of radionuclide concentration in building materials used in Japan

The specific activities of 238U, 232Th, and 40K in selected building materials used in Japan were measured using a high-purity germanium detector. The uranium and thorium concentrations were determined from same samples using inductively coupled plasma mass spectrometry. There was a good agreement between the measurement of uranium and thorium with both methods (R2 = 0.94, and 0.97, respectively). Based on the specific activities, we have estimated some hazard indexes such as radium equivalent activities (Raeq), external hazard index (Hex), internal hazard index (Hin), annual gonadal equivalent dose (AGED), internal alpha dose, mass exhalation rate and emanation coefficient of radon.

Exposure to high background radiation level in the tin mining area of Jos Plateau,Nigeria

The present work deals with the radioactivity of samples of tin tailings collected from amining site in Jos, Nigeria. The activity concentrations of the samples were measured usinga gamma-ray spectrometer with a hyper-pure germanium detector. In situ dose rates atthe site were also measured using a precalibrated survey meter. Potassium-40was not detected in any of the studied samples. The activity concentrations of238U and232Th rangedfrom 17.1 × 102 to 16.6 × 103 Bq kg−1 andfrom 52.9 × 102 to47.5 × 103 Bq kg−1, with meanvalues of 72.2 × 102 and 16.8 × 103 Bq kg−1, respectively. The absorbed dose rates were between 4.0 and36.3 µGy h−1, with amean value of 13.5 µGy h−1, which is much higher than the world average of0.06 µGy h−1 for soil. The calculated effective dose rates varied between 2.8 and25.4 µSv h−1, with amean value of 9.4 µSv h−1, whereas the effective dose rates obtained for the in situ measurement varied between 6.0 and28.0 µSv h−1. The annual gonadal dose equivalent was calculated as 92.4 mSv. This is muchhigher than the world average dose equivalent rate to individuals from soil(0.30 mSv y−1).

Determination of radioactivity levels and hazards of soil and sediment samples in Fırtına Valley (Rize, Turkey)

The natural radioactivity levels in soil and sediment samples of Fırtına Valley have been determined. To our knowledge, there seems to be no information about radioactivity level in the Fırtına Valley soils and sediments so far. For this reason, soil and sediment samples were collected along the Fırtına Valley and analysis on the collected samples were carried out to determine 238U, 232Th, 40K and 137Cs radioisotopes using high purity germanium detector. The activity concentrations obtained for 226Ra, 214Pb, 214Bi, 228Ac, 208Tl, 40K and 137Cs are given in the unit of Bq/kg. The results have been compared with other radioactivity measurements in different country's soils and sediments. The radium equivalent activity (Ra eq), the absorbed dose rate ( D), the external hazard index ( H ex), the annual gonadal dose equivalent (AGDE) and the annual effective dose equivalent (AEDE) were also calculated and compared with the international recommended values.

Radiometric analysis and radiological hazards of Chinese commercial marble

The activity concentrations of 226Ra, 232Th and 40K in commercial marble materials have been determined using a NaI(Tl) γ-ray spectrometer with a matrix-inversion-based spectral stripping technique. Knowledge of radioactivity present in marble materials enables one to assess any possible radiological risks to human health. The concentrations of 226Ra, 232Th and 40K in Chinese commercial marble range from 8.4 to 157.4, 5.6 to 165.5 and 44.1 to 1352.7 Bq kg−1, respectively. The natural radionuclide concentration varied with color and production site of commercial marble. The activity concentrations of 226Ra, 232Th and 40K in white, gray, black, green and yellow marble samples are comparatively smaller than those in brown and red marble samples. The radium equivalent activity (Raeq), the external hazard index (H ex), the internal hazard index (H in) and the annual gonadal dose equivalent were also calculated and compared with the internationally recommended values. One type of brown commercial marble (TSB) of China does not satisfy the universal standards.

Radiometric analysis of Chinese commercial granites

Due to the widespread use of granites as building and ornamental materials, measurements of 226Ra, 232Th and 40K activities in commercial granites have been carried out using a NaI(Tl)g-ray spectrometer with a matrix-inversion-based spectral stripping technique. The concentrations of 226Ra, 232Th and 40K in Chinese commercial granite range from 14.5 to 204.7 Bq. kg-1, 16.7 to 186.7 Bq. kg-1and 185.7 to 1745.6 Bq. kg-1, respectively. The mean values of the activity concentrations of 226Ra, 232Th and 40K in red and pink commercial granites are all higher than those in black and gray commercial ones. The radium equivalent activity (Raeq), the external hazard index (H ex), the internal hazard index (H in ) and the annual gonadal dose equivalent (AGDE) were also calculated and compared to the international recommended values. Six types of red commercial granites (CBR, MLR, QXR, PBR, JXR, LQR, YDR and TSR) of China do not satisfy the universal standards.

Exposure to radiation from the natural radioactivity in Jordanian building materials

The natural radioactivity due to the presence of (226)Ra, (232)Th and (40)K in selected building materials used in Jordanian building constructions has been measured using gamma-ray spectrometer with a Hyper Pure germanium detector. The average activity concentrations observed in different building materials ranged from 27.7 +/- 7.5 to 70.4 +/- 2.8, 5.9 +/- 0.67 to 32.9 +/- 3.9 and 30.8 +/- 0.87 to 58.5 +/- 1.5 for (226)Ra, (232)Th and (40)K, respectively. The activity concentrations of (226)Ra measured in fine aggregates was found to be among the highest values obtained in this work. The ranges of the calculated Ra-equivalent were found to be lower than those values recommended for construction materials (370 Bq kg(-1)). The average internal and external hazard indices were found to be <1. The average of the calculated annual gonadal equivalent dose was found to be 198 microSv y(-1). Results indicate no significant radiological hazards arise from using such materials in building construction.

Part 8 Some photos during the conference

The gamma spectrometric analysis of different brands of cement used as building and construction material in Nigeria has been carried out in this study. Samples of 12 brands of gray Ordinary Portland Cement (OPC) and 5 brands of white cement of six samples each were collected and analyzed for their radiological content using gamma spectrometry method. The average value of 226Ra, 232Th, and 40K for OPC is 30.2 ± 10.4 Bq kg− 1, 24.6 ± 7.1 Bq kg− 1, and 251.3 ± 27.6 Bq kg− 1 respectively and the average value for the white cement is 41.9 ± 16.7 Bq kg− 1, 30.1 ± 9.4 Bq kg− 1 and 340.2 ± 37.7 Bq kg− 1 respectively. The total average content of 226Ra, 232Th, and 40K for all the cement brand samples are 36.1 ± 13.6 Bq kg− 1, 27.4 ± 8.3 Bq kg− 1, and 295.8 ± 32.7 Bq kg− 1 respectively. These values obtained are lower when compared to the world average values (226Ra-50 Bq kg− 1, 232Th-50 Bq kg− 1 and 40K-500 Bq kg− 1) for building materials. The estimated radium equivalent activities (Raeq), representative index (Iγ), average absorbed γ-dose rate (D), the annual effective dose rate (AEDE), annual gonadal dose equivalent (AGDE) external and internal hazard indices and the Excess life cancer risk (ELCR) were lower than the recommended safe limit and are comparable with results from similar studies conducted in other countries. The evaluated mean gonadal dose equivalents of three cement brand samples were found to be higher than the world average for building material while others are less than the world average. A comparison of the average activity values obtained in Nigeria cement and other countries of the world show that those countries with history of high radionuclide solid minerals have activity concentration far above that of Nigerian cement, while these values agreed with those obtained in other countries.

Specific activity and hazards of granite samples collected from the Eastern Desert of Egypt

Fifty granitic rock samples were collected from different plutons in the central part of the Eastern Desert of Egypt and were analyzed for specific concentrations of 238U, 232Th and 40K radionuclei. The measurements were carried out using a high performance and stability Nomad Plus spectroscopy system attached to a 1.7 keV (FWHM) HPGe detector. The spectra were analyzed using the direct gamma counting comparison method as well as the traditional absolute efficiency curve method. The highest average value of 238U concentration (1184 Bq kg −1) was observed at EI Misikat region whereas the highest average values of 40K and 232Th concentration (2301.8 and 162.5 Bq kg −1 respectively), were detected at Gabal Homret Waggat area. The radium equivalent activity (Ra eq), the absorbed dose rate ( D), the external hazard index ( H ex) and the annual gonadal dose equivalent were also calculated and compared to the international recommended values. Radon exhalation rate from the rock samples were measured using the activated charcoal canister method. The average value of radon exhalation varies from 0.052 to 0.69 Bq m −2 h −1 and depends on the specific concentration of uranium.